mirror of https://gitee.com/openkylin/linux.git
5917 lines
152 KiB
C
5917 lines
152 KiB
C
/*
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* Copyright (C) 2007,2008 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/rbtree.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "print-tree.h"
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#include "locking.h"
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static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, struct btrfs_path *path, int level);
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static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, struct btrfs_key *ins_key,
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struct btrfs_path *path, int data_size, int extend);
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static int push_node_left(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct extent_buffer *dst,
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struct extent_buffer *src, int empty);
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static int balance_node_right(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct extent_buffer *dst_buf,
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struct extent_buffer *src_buf);
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static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
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int level, int slot);
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static int tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
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struct extent_buffer *eb);
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struct btrfs_path *btrfs_alloc_path(void)
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{
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struct btrfs_path *path;
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path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
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return path;
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}
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/*
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* set all locked nodes in the path to blocking locks. This should
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* be done before scheduling
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*/
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noinline void btrfs_set_path_blocking(struct btrfs_path *p)
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{
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int i;
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for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
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if (!p->nodes[i] || !p->locks[i])
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continue;
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btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]);
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if (p->locks[i] == BTRFS_READ_LOCK)
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p->locks[i] = BTRFS_READ_LOCK_BLOCKING;
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else if (p->locks[i] == BTRFS_WRITE_LOCK)
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p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING;
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}
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}
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/*
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* reset all the locked nodes in the patch to spinning locks.
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*
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* held is used to keep lockdep happy, when lockdep is enabled
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* we set held to a blocking lock before we go around and
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* retake all the spinlocks in the path. You can safely use NULL
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* for held
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*/
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noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
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struct extent_buffer *held, int held_rw)
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{
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int i;
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if (held) {
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btrfs_set_lock_blocking_rw(held, held_rw);
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if (held_rw == BTRFS_WRITE_LOCK)
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held_rw = BTRFS_WRITE_LOCK_BLOCKING;
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else if (held_rw == BTRFS_READ_LOCK)
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held_rw = BTRFS_READ_LOCK_BLOCKING;
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}
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btrfs_set_path_blocking(p);
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for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
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if (p->nodes[i] && p->locks[i]) {
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btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]);
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if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING)
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p->locks[i] = BTRFS_WRITE_LOCK;
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else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING)
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p->locks[i] = BTRFS_READ_LOCK;
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}
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}
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if (held)
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btrfs_clear_lock_blocking_rw(held, held_rw);
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}
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/* this also releases the path */
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void btrfs_free_path(struct btrfs_path *p)
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{
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if (!p)
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return;
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btrfs_release_path(p);
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kmem_cache_free(btrfs_path_cachep, p);
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}
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/*
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* path release drops references on the extent buffers in the path
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* and it drops any locks held by this path
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*
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* It is safe to call this on paths that no locks or extent buffers held.
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*/
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noinline void btrfs_release_path(struct btrfs_path *p)
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{
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int i;
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for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
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p->slots[i] = 0;
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if (!p->nodes[i])
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continue;
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if (p->locks[i]) {
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btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
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p->locks[i] = 0;
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}
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free_extent_buffer(p->nodes[i]);
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p->nodes[i] = NULL;
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}
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}
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/*
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* safely gets a reference on the root node of a tree. A lock
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* is not taken, so a concurrent writer may put a different node
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* at the root of the tree. See btrfs_lock_root_node for the
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* looping required.
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*
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* The extent buffer returned by this has a reference taken, so
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* it won't disappear. It may stop being the root of the tree
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* at any time because there are no locks held.
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*/
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struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
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{
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struct extent_buffer *eb;
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while (1) {
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rcu_read_lock();
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eb = rcu_dereference(root->node);
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/*
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* RCU really hurts here, we could free up the root node because
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* it was cow'ed but we may not get the new root node yet so do
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* the inc_not_zero dance and if it doesn't work then
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* synchronize_rcu and try again.
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*/
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if (atomic_inc_not_zero(&eb->refs)) {
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rcu_read_unlock();
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break;
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}
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rcu_read_unlock();
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synchronize_rcu();
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}
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return eb;
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}
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/* loop around taking references on and locking the root node of the
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* tree until you end up with a lock on the root. A locked buffer
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* is returned, with a reference held.
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*/
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struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
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{
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struct extent_buffer *eb;
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while (1) {
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eb = btrfs_root_node(root);
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btrfs_tree_lock(eb);
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if (eb == root->node)
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break;
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btrfs_tree_unlock(eb);
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free_extent_buffer(eb);
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}
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return eb;
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}
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/* loop around taking references on and locking the root node of the
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* tree until you end up with a lock on the root. A locked buffer
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* is returned, with a reference held.
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*/
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static struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
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{
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struct extent_buffer *eb;
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while (1) {
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eb = btrfs_root_node(root);
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btrfs_tree_read_lock(eb);
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if (eb == root->node)
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break;
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btrfs_tree_read_unlock(eb);
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free_extent_buffer(eb);
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}
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return eb;
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}
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/* cowonly root (everything not a reference counted cow subvolume), just get
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* put onto a simple dirty list. transaction.c walks this to make sure they
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* get properly updated on disk.
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*/
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static void add_root_to_dirty_list(struct btrfs_root *root)
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{
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if (test_bit(BTRFS_ROOT_DIRTY, &root->state) ||
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!test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state))
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return;
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spin_lock(&root->fs_info->trans_lock);
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if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
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/* Want the extent tree to be the last on the list */
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if (root->objectid == BTRFS_EXTENT_TREE_OBJECTID)
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list_move_tail(&root->dirty_list,
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&root->fs_info->dirty_cowonly_roots);
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else
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list_move(&root->dirty_list,
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&root->fs_info->dirty_cowonly_roots);
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}
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spin_unlock(&root->fs_info->trans_lock);
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}
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/*
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* used by snapshot creation to make a copy of a root for a tree with
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* a given objectid. The buffer with the new root node is returned in
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* cow_ret, and this func returns zero on success or a negative error code.
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*/
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int btrfs_copy_root(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct extent_buffer *buf,
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struct extent_buffer **cow_ret, u64 new_root_objectid)
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{
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struct extent_buffer *cow;
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int ret = 0;
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int level;
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struct btrfs_disk_key disk_key;
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WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
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trans->transid != root->fs_info->running_transaction->transid);
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WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
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trans->transid != root->last_trans);
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level = btrfs_header_level(buf);
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if (level == 0)
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btrfs_item_key(buf, &disk_key, 0);
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else
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btrfs_node_key(buf, &disk_key, 0);
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cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,
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&disk_key, level, buf->start, 0);
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if (IS_ERR(cow))
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return PTR_ERR(cow);
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copy_extent_buffer(cow, buf, 0, 0, cow->len);
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btrfs_set_header_bytenr(cow, cow->start);
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btrfs_set_header_generation(cow, trans->transid);
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btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
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btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
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BTRFS_HEADER_FLAG_RELOC);
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if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
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btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
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else
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btrfs_set_header_owner(cow, new_root_objectid);
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write_extent_buffer(cow, root->fs_info->fsid, btrfs_header_fsid(),
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BTRFS_FSID_SIZE);
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WARN_ON(btrfs_header_generation(buf) > trans->transid);
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if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
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ret = btrfs_inc_ref(trans, root, cow, 1);
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else
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ret = btrfs_inc_ref(trans, root, cow, 0);
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if (ret)
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return ret;
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btrfs_mark_buffer_dirty(cow);
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*cow_ret = cow;
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return 0;
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}
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enum mod_log_op {
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MOD_LOG_KEY_REPLACE,
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MOD_LOG_KEY_ADD,
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MOD_LOG_KEY_REMOVE,
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MOD_LOG_KEY_REMOVE_WHILE_FREEING,
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MOD_LOG_KEY_REMOVE_WHILE_MOVING,
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MOD_LOG_MOVE_KEYS,
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MOD_LOG_ROOT_REPLACE,
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};
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struct tree_mod_move {
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int dst_slot;
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int nr_items;
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};
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struct tree_mod_root {
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u64 logical;
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u8 level;
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};
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struct tree_mod_elem {
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struct rb_node node;
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u64 index; /* shifted logical */
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u64 seq;
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enum mod_log_op op;
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/* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
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int slot;
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/* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
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u64 generation;
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/* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
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struct btrfs_disk_key key;
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u64 blockptr;
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/* this is used for op == MOD_LOG_MOVE_KEYS */
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struct tree_mod_move move;
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/* this is used for op == MOD_LOG_ROOT_REPLACE */
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struct tree_mod_root old_root;
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};
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static inline void tree_mod_log_read_lock(struct btrfs_fs_info *fs_info)
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{
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read_lock(&fs_info->tree_mod_log_lock);
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}
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static inline void tree_mod_log_read_unlock(struct btrfs_fs_info *fs_info)
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{
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read_unlock(&fs_info->tree_mod_log_lock);
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}
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static inline void tree_mod_log_write_lock(struct btrfs_fs_info *fs_info)
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{
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write_lock(&fs_info->tree_mod_log_lock);
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}
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static inline void tree_mod_log_write_unlock(struct btrfs_fs_info *fs_info)
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{
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write_unlock(&fs_info->tree_mod_log_lock);
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}
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/*
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* Pull a new tree mod seq number for our operation.
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*/
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static inline u64 btrfs_inc_tree_mod_seq(struct btrfs_fs_info *fs_info)
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{
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return atomic64_inc_return(&fs_info->tree_mod_seq);
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}
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/*
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* This adds a new blocker to the tree mod log's blocker list if the @elem
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* passed does not already have a sequence number set. So when a caller expects
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* to record tree modifications, it should ensure to set elem->seq to zero
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* before calling btrfs_get_tree_mod_seq.
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* Returns a fresh, unused tree log modification sequence number, even if no new
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* blocker was added.
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*/
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u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
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struct seq_list *elem)
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{
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tree_mod_log_write_lock(fs_info);
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spin_lock(&fs_info->tree_mod_seq_lock);
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if (!elem->seq) {
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elem->seq = btrfs_inc_tree_mod_seq(fs_info);
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list_add_tail(&elem->list, &fs_info->tree_mod_seq_list);
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}
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spin_unlock(&fs_info->tree_mod_seq_lock);
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tree_mod_log_write_unlock(fs_info);
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return elem->seq;
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}
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void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
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struct seq_list *elem)
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{
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struct rb_root *tm_root;
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struct rb_node *node;
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struct rb_node *next;
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struct seq_list *cur_elem;
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struct tree_mod_elem *tm;
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u64 min_seq = (u64)-1;
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u64 seq_putting = elem->seq;
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if (!seq_putting)
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return;
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spin_lock(&fs_info->tree_mod_seq_lock);
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list_del(&elem->list);
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elem->seq = 0;
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list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) {
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if (cur_elem->seq < min_seq) {
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if (seq_putting > cur_elem->seq) {
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/*
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* blocker with lower sequence number exists, we
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* cannot remove anything from the log
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*/
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spin_unlock(&fs_info->tree_mod_seq_lock);
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return;
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}
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min_seq = cur_elem->seq;
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}
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}
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spin_unlock(&fs_info->tree_mod_seq_lock);
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/*
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* anything that's lower than the lowest existing (read: blocked)
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* sequence number can be removed from the tree.
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*/
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tree_mod_log_write_lock(fs_info);
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tm_root = &fs_info->tree_mod_log;
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for (node = rb_first(tm_root); node; node = next) {
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next = rb_next(node);
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tm = container_of(node, struct tree_mod_elem, node);
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if (tm->seq > min_seq)
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continue;
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rb_erase(node, tm_root);
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kfree(tm);
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}
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tree_mod_log_write_unlock(fs_info);
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}
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/*
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* key order of the log:
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* index -> sequence
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*
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* the index is the shifted logical of the *new* root node for root replace
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* operations, or the shifted logical of the affected block for all other
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* operations.
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*
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* Note: must be called with write lock (tree_mod_log_write_lock).
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*/
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static noinline int
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__tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
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{
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struct rb_root *tm_root;
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struct rb_node **new;
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struct rb_node *parent = NULL;
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struct tree_mod_elem *cur;
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BUG_ON(!tm);
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tm->seq = btrfs_inc_tree_mod_seq(fs_info);
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tm_root = &fs_info->tree_mod_log;
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new = &tm_root->rb_node;
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while (*new) {
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cur = container_of(*new, struct tree_mod_elem, node);
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parent = *new;
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if (cur->index < tm->index)
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new = &((*new)->rb_left);
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else if (cur->index > tm->index)
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new = &((*new)->rb_right);
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else if (cur->seq < tm->seq)
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new = &((*new)->rb_left);
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else if (cur->seq > tm->seq)
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new = &((*new)->rb_right);
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else
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return -EEXIST;
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}
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rb_link_node(&tm->node, parent, new);
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rb_insert_color(&tm->node, tm_root);
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return 0;
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}
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/*
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* Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
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* returns zero with the tree_mod_log_lock acquired. The caller must hold
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* this until all tree mod log insertions are recorded in the rb tree and then
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* call tree_mod_log_write_unlock() to release.
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*/
|
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static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
|
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struct extent_buffer *eb) {
|
|
smp_mb();
|
|
if (list_empty(&(fs_info)->tree_mod_seq_list))
|
|
return 1;
|
|
if (eb && btrfs_header_level(eb) == 0)
|
|
return 1;
|
|
|
|
tree_mod_log_write_lock(fs_info);
|
|
if (list_empty(&(fs_info)->tree_mod_seq_list)) {
|
|
tree_mod_log_write_unlock(fs_info);
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
|
|
static inline int tree_mod_need_log(const struct btrfs_fs_info *fs_info,
|
|
struct extent_buffer *eb)
|
|
{
|
|
smp_mb();
|
|
if (list_empty(&(fs_info)->tree_mod_seq_list))
|
|
return 0;
|
|
if (eb && btrfs_header_level(eb) == 0)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static struct tree_mod_elem *
|
|
alloc_tree_mod_elem(struct extent_buffer *eb, int slot,
|
|
enum mod_log_op op, gfp_t flags)
|
|
{
|
|
struct tree_mod_elem *tm;
|
|
|
|
tm = kzalloc(sizeof(*tm), flags);
|
|
if (!tm)
|
|
return NULL;
|
|
|
|
tm->index = eb->start >> PAGE_CACHE_SHIFT;
|
|
if (op != MOD_LOG_KEY_ADD) {
|
|
btrfs_node_key(eb, &tm->key, slot);
|
|
tm->blockptr = btrfs_node_blockptr(eb, slot);
|
|
}
|
|
tm->op = op;
|
|
tm->slot = slot;
|
|
tm->generation = btrfs_node_ptr_generation(eb, slot);
|
|
RB_CLEAR_NODE(&tm->node);
|
|
|
|
return tm;
|
|
}
|
|
|
|
static noinline int
|
|
tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
|
|
struct extent_buffer *eb, int slot,
|
|
enum mod_log_op op, gfp_t flags)
|
|
{
|
|
struct tree_mod_elem *tm;
|
|
int ret;
|
|
|
|
if (!tree_mod_need_log(fs_info, eb))
|
|
return 0;
|
|
|
|
tm = alloc_tree_mod_elem(eb, slot, op, flags);
|
|
if (!tm)
|
|
return -ENOMEM;
|
|
|
|
if (tree_mod_dont_log(fs_info, eb)) {
|
|
kfree(tm);
|
|
return 0;
|
|
}
|
|
|
|
ret = __tree_mod_log_insert(fs_info, tm);
|
|
tree_mod_log_write_unlock(fs_info);
|
|
if (ret)
|
|
kfree(tm);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static noinline int
|
|
tree_mod_log_insert_move(struct btrfs_fs_info *fs_info,
|
|
struct extent_buffer *eb, int dst_slot, int src_slot,
|
|
int nr_items, gfp_t flags)
|
|
{
|
|
struct tree_mod_elem *tm = NULL;
|
|
struct tree_mod_elem **tm_list = NULL;
|
|
int ret = 0;
|
|
int i;
|
|
int locked = 0;
|
|
|
|
if (!tree_mod_need_log(fs_info, eb))
|
|
return 0;
|
|
|
|
tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), flags);
|
|
if (!tm_list)
|
|
return -ENOMEM;
|
|
|
|
tm = kzalloc(sizeof(*tm), flags);
|
|
if (!tm) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
|
|
tm->index = eb->start >> PAGE_CACHE_SHIFT;
|
|
tm->slot = src_slot;
|
|
tm->move.dst_slot = dst_slot;
|
|
tm->move.nr_items = nr_items;
|
|
tm->op = MOD_LOG_MOVE_KEYS;
|
|
|
|
for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
|
|
tm_list[i] = alloc_tree_mod_elem(eb, i + dst_slot,
|
|
MOD_LOG_KEY_REMOVE_WHILE_MOVING, flags);
|
|
if (!tm_list[i]) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
}
|
|
|
|
if (tree_mod_dont_log(fs_info, eb))
|
|
goto free_tms;
|
|
locked = 1;
|
|
|
|
/*
|
|
* When we override something during the move, we log these removals.
|
|
* This can only happen when we move towards the beginning of the
|
|
* buffer, i.e. dst_slot < src_slot.
|
|
*/
|
|
for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
|
|
ret = __tree_mod_log_insert(fs_info, tm_list[i]);
|
|
if (ret)
|
|
goto free_tms;
|
|
}
|
|
|
|
ret = __tree_mod_log_insert(fs_info, tm);
|
|
if (ret)
|
|
goto free_tms;
|
|
tree_mod_log_write_unlock(fs_info);
|
|
kfree(tm_list);
|
|
|
|
return 0;
|
|
free_tms:
|
|
for (i = 0; i < nr_items; i++) {
|
|
if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
|
|
rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
|
|
kfree(tm_list[i]);
|
|
}
|
|
if (locked)
|
|
tree_mod_log_write_unlock(fs_info);
|
|
kfree(tm_list);
|
|
kfree(tm);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static inline int
|
|
__tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
|
|
struct tree_mod_elem **tm_list,
|
|
int nritems)
|
|
{
|
|
int i, j;
|
|
int ret;
|
|
|
|
for (i = nritems - 1; i >= 0; i--) {
|
|
ret = __tree_mod_log_insert(fs_info, tm_list[i]);
|
|
if (ret) {
|
|
for (j = nritems - 1; j > i; j--)
|
|
rb_erase(&tm_list[j]->node,
|
|
&fs_info->tree_mod_log);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static noinline int
|
|
tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
|
|
struct extent_buffer *old_root,
|
|
struct extent_buffer *new_root, gfp_t flags,
|
|
int log_removal)
|
|
{
|
|
struct tree_mod_elem *tm = NULL;
|
|
struct tree_mod_elem **tm_list = NULL;
|
|
int nritems = 0;
|
|
int ret = 0;
|
|
int i;
|
|
|
|
if (!tree_mod_need_log(fs_info, NULL))
|
|
return 0;
|
|
|
|
if (log_removal && btrfs_header_level(old_root) > 0) {
|
|
nritems = btrfs_header_nritems(old_root);
|
|
tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *),
|
|
flags);
|
|
if (!tm_list) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
for (i = 0; i < nritems; i++) {
|
|
tm_list[i] = alloc_tree_mod_elem(old_root, i,
|
|
MOD_LOG_KEY_REMOVE_WHILE_FREEING, flags);
|
|
if (!tm_list[i]) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
}
|
|
}
|
|
|
|
tm = kzalloc(sizeof(*tm), flags);
|
|
if (!tm) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
|
|
tm->index = new_root->start >> PAGE_CACHE_SHIFT;
|
|
tm->old_root.logical = old_root->start;
|
|
tm->old_root.level = btrfs_header_level(old_root);
|
|
tm->generation = btrfs_header_generation(old_root);
|
|
tm->op = MOD_LOG_ROOT_REPLACE;
|
|
|
|
if (tree_mod_dont_log(fs_info, NULL))
|
|
goto free_tms;
|
|
|
|
if (tm_list)
|
|
ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
|
|
if (!ret)
|
|
ret = __tree_mod_log_insert(fs_info, tm);
|
|
|
|
tree_mod_log_write_unlock(fs_info);
|
|
if (ret)
|
|
goto free_tms;
|
|
kfree(tm_list);
|
|
|
|
return ret;
|
|
|
|
free_tms:
|
|
if (tm_list) {
|
|
for (i = 0; i < nritems; i++)
|
|
kfree(tm_list[i]);
|
|
kfree(tm_list);
|
|
}
|
|
kfree(tm);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct tree_mod_elem *
|
|
__tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq,
|
|
int smallest)
|
|
{
|
|
struct rb_root *tm_root;
|
|
struct rb_node *node;
|
|
struct tree_mod_elem *cur = NULL;
|
|
struct tree_mod_elem *found = NULL;
|
|
u64 index = start >> PAGE_CACHE_SHIFT;
|
|
|
|
tree_mod_log_read_lock(fs_info);
|
|
tm_root = &fs_info->tree_mod_log;
|
|
node = tm_root->rb_node;
|
|
while (node) {
|
|
cur = container_of(node, struct tree_mod_elem, node);
|
|
if (cur->index < index) {
|
|
node = node->rb_left;
|
|
} else if (cur->index > index) {
|
|
node = node->rb_right;
|
|
} else if (cur->seq < min_seq) {
|
|
node = node->rb_left;
|
|
} else if (!smallest) {
|
|
/* we want the node with the highest seq */
|
|
if (found)
|
|
BUG_ON(found->seq > cur->seq);
|
|
found = cur;
|
|
node = node->rb_left;
|
|
} else if (cur->seq > min_seq) {
|
|
/* we want the node with the smallest seq */
|
|
if (found)
|
|
BUG_ON(found->seq < cur->seq);
|
|
found = cur;
|
|
node = node->rb_right;
|
|
} else {
|
|
found = cur;
|
|
break;
|
|
}
|
|
}
|
|
tree_mod_log_read_unlock(fs_info);
|
|
|
|
return found;
|
|
}
|
|
|
|
/*
|
|
* this returns the element from the log with the smallest time sequence
|
|
* value that's in the log (the oldest log item). any element with a time
|
|
* sequence lower than min_seq will be ignored.
|
|
*/
|
|
static struct tree_mod_elem *
|
|
tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start,
|
|
u64 min_seq)
|
|
{
|
|
return __tree_mod_log_search(fs_info, start, min_seq, 1);
|
|
}
|
|
|
|
/*
|
|
* this returns the element from the log with the largest time sequence
|
|
* value that's in the log (the most recent log item). any element with
|
|
* a time sequence lower than min_seq will be ignored.
|
|
*/
|
|
static struct tree_mod_elem *
|
|
tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
|
|
{
|
|
return __tree_mod_log_search(fs_info, start, min_seq, 0);
|
|
}
|
|
|
|
static noinline int
|
|
tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
|
|
struct extent_buffer *src, unsigned long dst_offset,
|
|
unsigned long src_offset, int nr_items)
|
|
{
|
|
int ret = 0;
|
|
struct tree_mod_elem **tm_list = NULL;
|
|
struct tree_mod_elem **tm_list_add, **tm_list_rem;
|
|
int i;
|
|
int locked = 0;
|
|
|
|
if (!tree_mod_need_log(fs_info, NULL))
|
|
return 0;
|
|
|
|
if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0)
|
|
return 0;
|
|
|
|
tm_list = kcalloc(nr_items * 2, sizeof(struct tree_mod_elem *),
|
|
GFP_NOFS);
|
|
if (!tm_list)
|
|
return -ENOMEM;
|
|
|
|
tm_list_add = tm_list;
|
|
tm_list_rem = tm_list + nr_items;
|
|
for (i = 0; i < nr_items; i++) {
|
|
tm_list_rem[i] = alloc_tree_mod_elem(src, i + src_offset,
|
|
MOD_LOG_KEY_REMOVE, GFP_NOFS);
|
|
if (!tm_list_rem[i]) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
|
|
tm_list_add[i] = alloc_tree_mod_elem(dst, i + dst_offset,
|
|
MOD_LOG_KEY_ADD, GFP_NOFS);
|
|
if (!tm_list_add[i]) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
}
|
|
|
|
if (tree_mod_dont_log(fs_info, NULL))
|
|
goto free_tms;
|
|
locked = 1;
|
|
|
|
for (i = 0; i < nr_items; i++) {
|
|
ret = __tree_mod_log_insert(fs_info, tm_list_rem[i]);
|
|
if (ret)
|
|
goto free_tms;
|
|
ret = __tree_mod_log_insert(fs_info, tm_list_add[i]);
|
|
if (ret)
|
|
goto free_tms;
|
|
}
|
|
|
|
tree_mod_log_write_unlock(fs_info);
|
|
kfree(tm_list);
|
|
|
|
return 0;
|
|
|
|
free_tms:
|
|
for (i = 0; i < nr_items * 2; i++) {
|
|
if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
|
|
rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
|
|
kfree(tm_list[i]);
|
|
}
|
|
if (locked)
|
|
tree_mod_log_write_unlock(fs_info);
|
|
kfree(tm_list);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static inline void
|
|
tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
|
|
int dst_offset, int src_offset, int nr_items)
|
|
{
|
|
int ret;
|
|
ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset,
|
|
nr_items, GFP_NOFS);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
|
|
static noinline void
|
|
tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info,
|
|
struct extent_buffer *eb, int slot, int atomic)
|
|
{
|
|
int ret;
|
|
|
|
ret = tree_mod_log_insert_key(fs_info, eb, slot,
|
|
MOD_LOG_KEY_REPLACE,
|
|
atomic ? GFP_ATOMIC : GFP_NOFS);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
|
|
static noinline int
|
|
tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
|
|
{
|
|
struct tree_mod_elem **tm_list = NULL;
|
|
int nritems = 0;
|
|
int i;
|
|
int ret = 0;
|
|
|
|
if (btrfs_header_level(eb) == 0)
|
|
return 0;
|
|
|
|
if (!tree_mod_need_log(fs_info, NULL))
|
|
return 0;
|
|
|
|
nritems = btrfs_header_nritems(eb);
|
|
tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS);
|
|
if (!tm_list)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; i < nritems; i++) {
|
|
tm_list[i] = alloc_tree_mod_elem(eb, i,
|
|
MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS);
|
|
if (!tm_list[i]) {
|
|
ret = -ENOMEM;
|
|
goto free_tms;
|
|
}
|
|
}
|
|
|
|
if (tree_mod_dont_log(fs_info, eb))
|
|
goto free_tms;
|
|
|
|
ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
|
|
tree_mod_log_write_unlock(fs_info);
|
|
if (ret)
|
|
goto free_tms;
|
|
kfree(tm_list);
|
|
|
|
return 0;
|
|
|
|
free_tms:
|
|
for (i = 0; i < nritems; i++)
|
|
kfree(tm_list[i]);
|
|
kfree(tm_list);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static noinline void
|
|
tree_mod_log_set_root_pointer(struct btrfs_root *root,
|
|
struct extent_buffer *new_root_node,
|
|
int log_removal)
|
|
{
|
|
int ret;
|
|
ret = tree_mod_log_insert_root(root->fs_info, root->node,
|
|
new_root_node, GFP_NOFS, log_removal);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
|
|
/*
|
|
* check if the tree block can be shared by multiple trees
|
|
*/
|
|
int btrfs_block_can_be_shared(struct btrfs_root *root,
|
|
struct extent_buffer *buf)
|
|
{
|
|
/*
|
|
* Tree blocks not in refernece counted trees and tree roots
|
|
* are never shared. If a block was allocated after the last
|
|
* snapshot and the block was not allocated by tree relocation,
|
|
* we know the block is not shared.
|
|
*/
|
|
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
|
|
buf != root->node && buf != root->commit_root &&
|
|
(btrfs_header_generation(buf) <=
|
|
btrfs_root_last_snapshot(&root->root_item) ||
|
|
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
|
|
return 1;
|
|
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
|
|
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
|
|
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
|
|
return 1;
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct extent_buffer *buf,
|
|
struct extent_buffer *cow,
|
|
int *last_ref)
|
|
{
|
|
u64 refs;
|
|
u64 owner;
|
|
u64 flags;
|
|
u64 new_flags = 0;
|
|
int ret;
|
|
|
|
/*
|
|
* Backrefs update rules:
|
|
*
|
|
* Always use full backrefs for extent pointers in tree block
|
|
* allocated by tree relocation.
|
|
*
|
|
* If a shared tree block is no longer referenced by its owner
|
|
* tree (btrfs_header_owner(buf) == root->root_key.objectid),
|
|
* use full backrefs for extent pointers in tree block.
|
|
*
|
|
* If a tree block is been relocating
|
|
* (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
|
|
* use full backrefs for extent pointers in tree block.
|
|
* The reason for this is some operations (such as drop tree)
|
|
* are only allowed for blocks use full backrefs.
|
|
*/
|
|
|
|
if (btrfs_block_can_be_shared(root, buf)) {
|
|
ret = btrfs_lookup_extent_info(trans, root, buf->start,
|
|
btrfs_header_level(buf), 1,
|
|
&refs, &flags);
|
|
if (ret)
|
|
return ret;
|
|
if (refs == 0) {
|
|
ret = -EROFS;
|
|
btrfs_std_error(root->fs_info, ret);
|
|
return ret;
|
|
}
|
|
} else {
|
|
refs = 1;
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
|
|
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
|
|
flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
|
else
|
|
flags = 0;
|
|
}
|
|
|
|
owner = btrfs_header_owner(buf);
|
|
BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
|
|
!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
|
|
|
|
if (refs > 1) {
|
|
if ((owner == root->root_key.objectid ||
|
|
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
|
|
!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
|
|
ret = btrfs_inc_ref(trans, root, buf, 1);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
|
|
if (root->root_key.objectid ==
|
|
BTRFS_TREE_RELOC_OBJECTID) {
|
|
ret = btrfs_dec_ref(trans, root, buf, 0);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
ret = btrfs_inc_ref(trans, root, cow, 1);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
}
|
|
new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
|
} else {
|
|
|
|
if (root->root_key.objectid ==
|
|
BTRFS_TREE_RELOC_OBJECTID)
|
|
ret = btrfs_inc_ref(trans, root, cow, 1);
|
|
else
|
|
ret = btrfs_inc_ref(trans, root, cow, 0);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
}
|
|
if (new_flags != 0) {
|
|
int level = btrfs_header_level(buf);
|
|
|
|
ret = btrfs_set_disk_extent_flags(trans, root,
|
|
buf->start,
|
|
buf->len,
|
|
new_flags, level, 0);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
} else {
|
|
if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
|
|
if (root->root_key.objectid ==
|
|
BTRFS_TREE_RELOC_OBJECTID)
|
|
ret = btrfs_inc_ref(trans, root, cow, 1);
|
|
else
|
|
ret = btrfs_inc_ref(trans, root, cow, 0);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
ret = btrfs_dec_ref(trans, root, buf, 1);
|
|
BUG_ON(ret); /* -ENOMEM */
|
|
}
|
|
clean_tree_block(trans, root->fs_info, buf);
|
|
*last_ref = 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* does the dirty work in cow of a single block. The parent block (if
|
|
* supplied) is updated to point to the new cow copy. The new buffer is marked
|
|
* dirty and returned locked. If you modify the block it needs to be marked
|
|
* dirty again.
|
|
*
|
|
* search_start -- an allocation hint for the new block
|
|
*
|
|
* empty_size -- a hint that you plan on doing more cow. This is the size in
|
|
* bytes the allocator should try to find free next to the block it returns.
|
|
* This is just a hint and may be ignored by the allocator.
|
|
*/
|
|
static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct extent_buffer *buf,
|
|
struct extent_buffer *parent, int parent_slot,
|
|
struct extent_buffer **cow_ret,
|
|
u64 search_start, u64 empty_size)
|
|
{
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *cow;
|
|
int level, ret;
|
|
int last_ref = 0;
|
|
int unlock_orig = 0;
|
|
u64 parent_start;
|
|
|
|
if (*cow_ret == buf)
|
|
unlock_orig = 1;
|
|
|
|
btrfs_assert_tree_locked(buf);
|
|
|
|
WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
|
|
trans->transid != root->fs_info->running_transaction->transid);
|
|
WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
|
|
trans->transid != root->last_trans);
|
|
|
|
level = btrfs_header_level(buf);
|
|
|
|
if (level == 0)
|
|
btrfs_item_key(buf, &disk_key, 0);
|
|
else
|
|
btrfs_node_key(buf, &disk_key, 0);
|
|
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
|
|
if (parent)
|
|
parent_start = parent->start;
|
|
else
|
|
parent_start = 0;
|
|
} else
|
|
parent_start = 0;
|
|
|
|
cow = btrfs_alloc_tree_block(trans, root, parent_start,
|
|
root->root_key.objectid, &disk_key, level,
|
|
search_start, empty_size);
|
|
if (IS_ERR(cow))
|
|
return PTR_ERR(cow);
|
|
|
|
/* cow is set to blocking by btrfs_init_new_buffer */
|
|
|
|
copy_extent_buffer(cow, buf, 0, 0, cow->len);
|
|
btrfs_set_header_bytenr(cow, cow->start);
|
|
btrfs_set_header_generation(cow, trans->transid);
|
|
btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
|
|
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
|
|
BTRFS_HEADER_FLAG_RELOC);
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
|
|
btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
|
|
else
|
|
btrfs_set_header_owner(cow, root->root_key.objectid);
|
|
|
|
write_extent_buffer(cow, root->fs_info->fsid, btrfs_header_fsid(),
|
|
BTRFS_FSID_SIZE);
|
|
|
|
ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, root, ret);
|
|
return ret;
|
|
}
|
|
|
|
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
|
|
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, root, ret);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
if (buf == root->node) {
|
|
WARN_ON(parent && parent != buf);
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
|
|
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
|
|
parent_start = buf->start;
|
|
else
|
|
parent_start = 0;
|
|
|
|
extent_buffer_get(cow);
|
|
tree_mod_log_set_root_pointer(root, cow, 1);
|
|
rcu_assign_pointer(root->node, cow);
|
|
|
|
btrfs_free_tree_block(trans, root, buf, parent_start,
|
|
last_ref);
|
|
free_extent_buffer(buf);
|
|
add_root_to_dirty_list(root);
|
|
} else {
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
|
|
parent_start = parent->start;
|
|
else
|
|
parent_start = 0;
|
|
|
|
WARN_ON(trans->transid != btrfs_header_generation(parent));
|
|
tree_mod_log_insert_key(root->fs_info, parent, parent_slot,
|
|
MOD_LOG_KEY_REPLACE, GFP_NOFS);
|
|
btrfs_set_node_blockptr(parent, parent_slot,
|
|
cow->start);
|
|
btrfs_set_node_ptr_generation(parent, parent_slot,
|
|
trans->transid);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
if (last_ref) {
|
|
ret = tree_mod_log_free_eb(root->fs_info, buf);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, root, ret);
|
|
return ret;
|
|
}
|
|
}
|
|
btrfs_free_tree_block(trans, root, buf, parent_start,
|
|
last_ref);
|
|
}
|
|
if (unlock_orig)
|
|
btrfs_tree_unlock(buf);
|
|
free_extent_buffer_stale(buf);
|
|
btrfs_mark_buffer_dirty(cow);
|
|
*cow_ret = cow;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* returns the logical address of the oldest predecessor of the given root.
|
|
* entries older than time_seq are ignored.
|
|
*/
|
|
static struct tree_mod_elem *
|
|
__tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
|
|
struct extent_buffer *eb_root, u64 time_seq)
|
|
{
|
|
struct tree_mod_elem *tm;
|
|
struct tree_mod_elem *found = NULL;
|
|
u64 root_logical = eb_root->start;
|
|
int looped = 0;
|
|
|
|
if (!time_seq)
|
|
return NULL;
|
|
|
|
/*
|
|
* the very last operation that's logged for a root is the replacement
|
|
* operation (if it is replaced at all). this has the index of the *new*
|
|
* root, making it the very first operation that's logged for this root.
|
|
*/
|
|
while (1) {
|
|
tm = tree_mod_log_search_oldest(fs_info, root_logical,
|
|
time_seq);
|
|
if (!looped && !tm)
|
|
return NULL;
|
|
/*
|
|
* if there are no tree operation for the oldest root, we simply
|
|
* return it. this should only happen if that (old) root is at
|
|
* level 0.
|
|
*/
|
|
if (!tm)
|
|
break;
|
|
|
|
/*
|
|
* if there's an operation that's not a root replacement, we
|
|
* found the oldest version of our root. normally, we'll find a
|
|
* MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
|
|
*/
|
|
if (tm->op != MOD_LOG_ROOT_REPLACE)
|
|
break;
|
|
|
|
found = tm;
|
|
root_logical = tm->old_root.logical;
|
|
looped = 1;
|
|
}
|
|
|
|
/* if there's no old root to return, return what we found instead */
|
|
if (!found)
|
|
found = tm;
|
|
|
|
return found;
|
|
}
|
|
|
|
/*
|
|
* tm is a pointer to the first operation to rewind within eb. then, all
|
|
* previous operations will be rewinded (until we reach something older than
|
|
* time_seq).
|
|
*/
|
|
static void
|
|
__tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
|
|
u64 time_seq, struct tree_mod_elem *first_tm)
|
|
{
|
|
u32 n;
|
|
struct rb_node *next;
|
|
struct tree_mod_elem *tm = first_tm;
|
|
unsigned long o_dst;
|
|
unsigned long o_src;
|
|
unsigned long p_size = sizeof(struct btrfs_key_ptr);
|
|
|
|
n = btrfs_header_nritems(eb);
|
|
tree_mod_log_read_lock(fs_info);
|
|
while (tm && tm->seq >= time_seq) {
|
|
/*
|
|
* all the operations are recorded with the operator used for
|
|
* the modification. as we're going backwards, we do the
|
|
* opposite of each operation here.
|
|
*/
|
|
switch (tm->op) {
|
|
case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
|
|
BUG_ON(tm->slot < n);
|
|
/* Fallthrough */
|
|
case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
|
|
case MOD_LOG_KEY_REMOVE:
|
|
btrfs_set_node_key(eb, &tm->key, tm->slot);
|
|
btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
|
|
btrfs_set_node_ptr_generation(eb, tm->slot,
|
|
tm->generation);
|
|
n++;
|
|
break;
|
|
case MOD_LOG_KEY_REPLACE:
|
|
BUG_ON(tm->slot >= n);
|
|
btrfs_set_node_key(eb, &tm->key, tm->slot);
|
|
btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
|
|
btrfs_set_node_ptr_generation(eb, tm->slot,
|
|
tm->generation);
|
|
break;
|
|
case MOD_LOG_KEY_ADD:
|
|
/* if a move operation is needed it's in the log */
|
|
n--;
|
|
break;
|
|
case MOD_LOG_MOVE_KEYS:
|
|
o_dst = btrfs_node_key_ptr_offset(tm->slot);
|
|
o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot);
|
|
memmove_extent_buffer(eb, o_dst, o_src,
|
|
tm->move.nr_items * p_size);
|
|
break;
|
|
case MOD_LOG_ROOT_REPLACE:
|
|
/*
|
|
* this operation is special. for roots, this must be
|
|
* handled explicitly before rewinding.
|
|
* for non-roots, this operation may exist if the node
|
|
* was a root: root A -> child B; then A gets empty and
|
|
* B is promoted to the new root. in the mod log, we'll
|
|
* have a root-replace operation for B, a tree block
|
|
* that is no root. we simply ignore that operation.
|
|
*/
|
|
break;
|
|
}
|
|
next = rb_next(&tm->node);
|
|
if (!next)
|
|
break;
|
|
tm = container_of(next, struct tree_mod_elem, node);
|
|
if (tm->index != first_tm->index)
|
|
break;
|
|
}
|
|
tree_mod_log_read_unlock(fs_info);
|
|
btrfs_set_header_nritems(eb, n);
|
|
}
|
|
|
|
/*
|
|
* Called with eb read locked. If the buffer cannot be rewinded, the same buffer
|
|
* is returned. If rewind operations happen, a fresh buffer is returned. The
|
|
* returned buffer is always read-locked. If the returned buffer is not the
|
|
* input buffer, the lock on the input buffer is released and the input buffer
|
|
* is freed (its refcount is decremented).
|
|
*/
|
|
static struct extent_buffer *
|
|
tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
|
|
struct extent_buffer *eb, u64 time_seq)
|
|
{
|
|
struct extent_buffer *eb_rewin;
|
|
struct tree_mod_elem *tm;
|
|
|
|
if (!time_seq)
|
|
return eb;
|
|
|
|
if (btrfs_header_level(eb) == 0)
|
|
return eb;
|
|
|
|
tm = tree_mod_log_search(fs_info, eb->start, time_seq);
|
|
if (!tm)
|
|
return eb;
|
|
|
|
btrfs_set_path_blocking(path);
|
|
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
|
|
|
|
if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
|
|
BUG_ON(tm->slot != 0);
|
|
eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start);
|
|
if (!eb_rewin) {
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
return NULL;
|
|
}
|
|
btrfs_set_header_bytenr(eb_rewin, eb->start);
|
|
btrfs_set_header_backref_rev(eb_rewin,
|
|
btrfs_header_backref_rev(eb));
|
|
btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb));
|
|
btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));
|
|
} else {
|
|
eb_rewin = btrfs_clone_extent_buffer(eb);
|
|
if (!eb_rewin) {
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
btrfs_clear_path_blocking(path, NULL, BTRFS_READ_LOCK);
|
|
btrfs_tree_read_unlock_blocking(eb);
|
|
free_extent_buffer(eb);
|
|
|
|
extent_buffer_get(eb_rewin);
|
|
btrfs_tree_read_lock(eb_rewin);
|
|
__tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
|
|
WARN_ON(btrfs_header_nritems(eb_rewin) >
|
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info->tree_root));
|
|
|
|
return eb_rewin;
|
|
}
|
|
|
|
/*
|
|
* get_old_root() rewinds the state of @root's root node to the given @time_seq
|
|
* value. If there are no changes, the current root->root_node is returned. If
|
|
* anything changed in between, there's a fresh buffer allocated on which the
|
|
* rewind operations are done. In any case, the returned buffer is read locked.
|
|
* Returns NULL on error (with no locks held).
|
|
*/
|
|
static inline struct extent_buffer *
|
|
get_old_root(struct btrfs_root *root, u64 time_seq)
|
|
{
|
|
struct tree_mod_elem *tm;
|
|
struct extent_buffer *eb = NULL;
|
|
struct extent_buffer *eb_root;
|
|
struct extent_buffer *old;
|
|
struct tree_mod_root *old_root = NULL;
|
|
u64 old_generation = 0;
|
|
u64 logical;
|
|
|
|
eb_root = btrfs_read_lock_root_node(root);
|
|
tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
|
|
if (!tm)
|
|
return eb_root;
|
|
|
|
if (tm->op == MOD_LOG_ROOT_REPLACE) {
|
|
old_root = &tm->old_root;
|
|
old_generation = tm->generation;
|
|
logical = old_root->logical;
|
|
} else {
|
|
logical = eb_root->start;
|
|
}
|
|
|
|
tm = tree_mod_log_search(root->fs_info, logical, time_seq);
|
|
if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
|
|
btrfs_tree_read_unlock(eb_root);
|
|
free_extent_buffer(eb_root);
|
|
old = read_tree_block(root, logical, 0);
|
|
if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) {
|
|
if (!IS_ERR(old))
|
|
free_extent_buffer(old);
|
|
btrfs_warn(root->fs_info,
|
|
"failed to read tree block %llu from get_old_root", logical);
|
|
} else {
|
|
eb = btrfs_clone_extent_buffer(old);
|
|
free_extent_buffer(old);
|
|
}
|
|
} else if (old_root) {
|
|
btrfs_tree_read_unlock(eb_root);
|
|
free_extent_buffer(eb_root);
|
|
eb = alloc_dummy_extent_buffer(root->fs_info, logical);
|
|
} else {
|
|
btrfs_set_lock_blocking_rw(eb_root, BTRFS_READ_LOCK);
|
|
eb = btrfs_clone_extent_buffer(eb_root);
|
|
btrfs_tree_read_unlock_blocking(eb_root);
|
|
free_extent_buffer(eb_root);
|
|
}
|
|
|
|
if (!eb)
|
|
return NULL;
|
|
extent_buffer_get(eb);
|
|
btrfs_tree_read_lock(eb);
|
|
if (old_root) {
|
|
btrfs_set_header_bytenr(eb, eb->start);
|
|
btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
|
|
btrfs_set_header_owner(eb, btrfs_header_owner(eb_root));
|
|
btrfs_set_header_level(eb, old_root->level);
|
|
btrfs_set_header_generation(eb, old_generation);
|
|
}
|
|
if (tm)
|
|
__tree_mod_log_rewind(root->fs_info, eb, time_seq, tm);
|
|
else
|
|
WARN_ON(btrfs_header_level(eb) != 0);
|
|
WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root));
|
|
|
|
return eb;
|
|
}
|
|
|
|
int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
|
|
{
|
|
struct tree_mod_elem *tm;
|
|
int level;
|
|
struct extent_buffer *eb_root = btrfs_root_node(root);
|
|
|
|
tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq);
|
|
if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
|
|
level = tm->old_root.level;
|
|
} else {
|
|
level = btrfs_header_level(eb_root);
|
|
}
|
|
free_extent_buffer(eb_root);
|
|
|
|
return level;
|
|
}
|
|
|
|
static inline int should_cow_block(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct extent_buffer *buf)
|
|
{
|
|
if (btrfs_test_is_dummy_root(root))
|
|
return 0;
|
|
|
|
/* ensure we can see the force_cow */
|
|
smp_rmb();
|
|
|
|
/*
|
|
* We do not need to cow a block if
|
|
* 1) this block is not created or changed in this transaction;
|
|
* 2) this block does not belong to TREE_RELOC tree;
|
|
* 3) the root is not forced COW.
|
|
*
|
|
* What is forced COW:
|
|
* when we create snapshot during commiting the transaction,
|
|
* after we've finished coping src root, we must COW the shared
|
|
* block to ensure the metadata consistency.
|
|
*/
|
|
if (btrfs_header_generation(buf) == trans->transid &&
|
|
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
|
|
!(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
|
|
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
|
|
!test_bit(BTRFS_ROOT_FORCE_COW, &root->state))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* cows a single block, see __btrfs_cow_block for the real work.
|
|
* This version of it has extra checks so that a block isn't cow'd more than
|
|
* once per transaction, as long as it hasn't been written yet
|
|
*/
|
|
noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct extent_buffer *buf,
|
|
struct extent_buffer *parent, int parent_slot,
|
|
struct extent_buffer **cow_ret)
|
|
{
|
|
u64 search_start;
|
|
int ret;
|
|
|
|
if (trans->transaction != root->fs_info->running_transaction)
|
|
WARN(1, KERN_CRIT "trans %llu running %llu\n",
|
|
trans->transid,
|
|
root->fs_info->running_transaction->transid);
|
|
|
|
if (trans->transid != root->fs_info->generation)
|
|
WARN(1, KERN_CRIT "trans %llu running %llu\n",
|
|
trans->transid, root->fs_info->generation);
|
|
|
|
if (!should_cow_block(trans, root, buf)) {
|
|
*cow_ret = buf;
|
|
return 0;
|
|
}
|
|
|
|
search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
|
|
|
|
if (parent)
|
|
btrfs_set_lock_blocking(parent);
|
|
btrfs_set_lock_blocking(buf);
|
|
|
|
ret = __btrfs_cow_block(trans, root, buf, parent,
|
|
parent_slot, cow_ret, search_start, 0);
|
|
|
|
trace_btrfs_cow_block(root, buf, *cow_ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper function for defrag to decide if two blocks pointed to by a
|
|
* node are actually close by
|
|
*/
|
|
static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
|
|
{
|
|
if (blocknr < other && other - (blocknr + blocksize) < 32768)
|
|
return 1;
|
|
if (blocknr > other && blocknr - (other + blocksize) < 32768)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* compare two keys in a memcmp fashion
|
|
*/
|
|
static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
|
|
{
|
|
struct btrfs_key k1;
|
|
|
|
btrfs_disk_key_to_cpu(&k1, disk);
|
|
|
|
return btrfs_comp_cpu_keys(&k1, k2);
|
|
}
|
|
|
|
/*
|
|
* same as comp_keys only with two btrfs_key's
|
|
*/
|
|
int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
|
|
{
|
|
if (k1->objectid > k2->objectid)
|
|
return 1;
|
|
if (k1->objectid < k2->objectid)
|
|
return -1;
|
|
if (k1->type > k2->type)
|
|
return 1;
|
|
if (k1->type < k2->type)
|
|
return -1;
|
|
if (k1->offset > k2->offset)
|
|
return 1;
|
|
if (k1->offset < k2->offset)
|
|
return -1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this is used by the defrag code to go through all the
|
|
* leaves pointed to by a node and reallocate them so that
|
|
* disk order is close to key order
|
|
*/
|
|
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct extent_buffer *parent,
|
|
int start_slot, u64 *last_ret,
|
|
struct btrfs_key *progress)
|
|
{
|
|
struct extent_buffer *cur;
|
|
u64 blocknr;
|
|
u64 gen;
|
|
u64 search_start = *last_ret;
|
|
u64 last_block = 0;
|
|
u64 other;
|
|
u32 parent_nritems;
|
|
int end_slot;
|
|
int i;
|
|
int err = 0;
|
|
int parent_level;
|
|
int uptodate;
|
|
u32 blocksize;
|
|
int progress_passed = 0;
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
parent_level = btrfs_header_level(parent);
|
|
|
|
WARN_ON(trans->transaction != root->fs_info->running_transaction);
|
|
WARN_ON(trans->transid != root->fs_info->generation);
|
|
|
|
parent_nritems = btrfs_header_nritems(parent);
|
|
blocksize = root->nodesize;
|
|
end_slot = parent_nritems - 1;
|
|
|
|
if (parent_nritems <= 1)
|
|
return 0;
|
|
|
|
btrfs_set_lock_blocking(parent);
|
|
|
|
for (i = start_slot; i <= end_slot; i++) {
|
|
int close = 1;
|
|
|
|
btrfs_node_key(parent, &disk_key, i);
|
|
if (!progress_passed && comp_keys(&disk_key, progress) < 0)
|
|
continue;
|
|
|
|
progress_passed = 1;
|
|
blocknr = btrfs_node_blockptr(parent, i);
|
|
gen = btrfs_node_ptr_generation(parent, i);
|
|
if (last_block == 0)
|
|
last_block = blocknr;
|
|
|
|
if (i > 0) {
|
|
other = btrfs_node_blockptr(parent, i - 1);
|
|
close = close_blocks(blocknr, other, blocksize);
|
|
}
|
|
if (!close && i < end_slot) {
|
|
other = btrfs_node_blockptr(parent, i + 1);
|
|
close = close_blocks(blocknr, other, blocksize);
|
|
}
|
|
if (close) {
|
|
last_block = blocknr;
|
|
continue;
|
|
}
|
|
|
|
cur = btrfs_find_tree_block(root->fs_info, blocknr);
|
|
if (cur)
|
|
uptodate = btrfs_buffer_uptodate(cur, gen, 0);
|
|
else
|
|
uptodate = 0;
|
|
if (!cur || !uptodate) {
|
|
if (!cur) {
|
|
cur = read_tree_block(root, blocknr, gen);
|
|
if (IS_ERR(cur)) {
|
|
return PTR_ERR(cur);
|
|
} else if (!extent_buffer_uptodate(cur)) {
|
|
free_extent_buffer(cur);
|
|
return -EIO;
|
|
}
|
|
} else if (!uptodate) {
|
|
err = btrfs_read_buffer(cur, gen);
|
|
if (err) {
|
|
free_extent_buffer(cur);
|
|
return err;
|
|
}
|
|
}
|
|
}
|
|
if (search_start == 0)
|
|
search_start = last_block;
|
|
|
|
btrfs_tree_lock(cur);
|
|
btrfs_set_lock_blocking(cur);
|
|
err = __btrfs_cow_block(trans, root, cur, parent, i,
|
|
&cur, search_start,
|
|
min(16 * blocksize,
|
|
(end_slot - i) * blocksize));
|
|
if (err) {
|
|
btrfs_tree_unlock(cur);
|
|
free_extent_buffer(cur);
|
|
break;
|
|
}
|
|
search_start = cur->start;
|
|
last_block = cur->start;
|
|
*last_ret = search_start;
|
|
btrfs_tree_unlock(cur);
|
|
free_extent_buffer(cur);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* The leaf data grows from end-to-front in the node.
|
|
* this returns the address of the start of the last item,
|
|
* which is the stop of the leaf data stack
|
|
*/
|
|
static inline unsigned int leaf_data_end(struct btrfs_root *root,
|
|
struct extent_buffer *leaf)
|
|
{
|
|
u32 nr = btrfs_header_nritems(leaf);
|
|
if (nr == 0)
|
|
return BTRFS_LEAF_DATA_SIZE(root);
|
|
return btrfs_item_offset_nr(leaf, nr - 1);
|
|
}
|
|
|
|
|
|
/*
|
|
* search for key in the extent_buffer. The items start at offset p,
|
|
* and they are item_size apart. There are 'max' items in p.
|
|
*
|
|
* the slot in the array is returned via slot, and it points to
|
|
* the place where you would insert key if it is not found in
|
|
* the array.
|
|
*
|
|
* slot may point to max if the key is bigger than all of the keys
|
|
*/
|
|
static noinline int generic_bin_search(struct extent_buffer *eb,
|
|
unsigned long p,
|
|
int item_size, struct btrfs_key *key,
|
|
int max, int *slot)
|
|
{
|
|
int low = 0;
|
|
int high = max;
|
|
int mid;
|
|
int ret;
|
|
struct btrfs_disk_key *tmp = NULL;
|
|
struct btrfs_disk_key unaligned;
|
|
unsigned long offset;
|
|
char *kaddr = NULL;
|
|
unsigned long map_start = 0;
|
|
unsigned long map_len = 0;
|
|
int err;
|
|
|
|
while (low < high) {
|
|
mid = (low + high) / 2;
|
|
offset = p + mid * item_size;
|
|
|
|
if (!kaddr || offset < map_start ||
|
|
(offset + sizeof(struct btrfs_disk_key)) >
|
|
map_start + map_len) {
|
|
|
|
err = map_private_extent_buffer(eb, offset,
|
|
sizeof(struct btrfs_disk_key),
|
|
&kaddr, &map_start, &map_len);
|
|
|
|
if (!err) {
|
|
tmp = (struct btrfs_disk_key *)(kaddr + offset -
|
|
map_start);
|
|
} else {
|
|
read_extent_buffer(eb, &unaligned,
|
|
offset, sizeof(unaligned));
|
|
tmp = &unaligned;
|
|
}
|
|
|
|
} else {
|
|
tmp = (struct btrfs_disk_key *)(kaddr + offset -
|
|
map_start);
|
|
}
|
|
ret = comp_keys(tmp, key);
|
|
|
|
if (ret < 0)
|
|
low = mid + 1;
|
|
else if (ret > 0)
|
|
high = mid;
|
|
else {
|
|
*slot = mid;
|
|
return 0;
|
|
}
|
|
}
|
|
*slot = low;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* simple bin_search frontend that does the right thing for
|
|
* leaves vs nodes
|
|
*/
|
|
static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
|
|
int level, int *slot)
|
|
{
|
|
if (level == 0)
|
|
return generic_bin_search(eb,
|
|
offsetof(struct btrfs_leaf, items),
|
|
sizeof(struct btrfs_item),
|
|
key, btrfs_header_nritems(eb),
|
|
slot);
|
|
else
|
|
return generic_bin_search(eb,
|
|
offsetof(struct btrfs_node, ptrs),
|
|
sizeof(struct btrfs_key_ptr),
|
|
key, btrfs_header_nritems(eb),
|
|
slot);
|
|
}
|
|
|
|
int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
|
|
int level, int *slot)
|
|
{
|
|
return bin_search(eb, key, level, slot);
|
|
}
|
|
|
|
static void root_add_used(struct btrfs_root *root, u32 size)
|
|
{
|
|
spin_lock(&root->accounting_lock);
|
|
btrfs_set_root_used(&root->root_item,
|
|
btrfs_root_used(&root->root_item) + size);
|
|
spin_unlock(&root->accounting_lock);
|
|
}
|
|
|
|
static void root_sub_used(struct btrfs_root *root, u32 size)
|
|
{
|
|
spin_lock(&root->accounting_lock);
|
|
btrfs_set_root_used(&root->root_item,
|
|
btrfs_root_used(&root->root_item) - size);
|
|
spin_unlock(&root->accounting_lock);
|
|
}
|
|
|
|
/* given a node and slot number, this reads the blocks it points to. The
|
|
* extent buffer is returned with a reference taken (but unlocked).
|
|
* NULL is returned on error.
|
|
*/
|
|
static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
|
|
struct extent_buffer *parent, int slot)
|
|
{
|
|
int level = btrfs_header_level(parent);
|
|
struct extent_buffer *eb;
|
|
|
|
if (slot < 0)
|
|
return NULL;
|
|
if (slot >= btrfs_header_nritems(parent))
|
|
return NULL;
|
|
|
|
BUG_ON(level == 0);
|
|
|
|
eb = read_tree_block(root, btrfs_node_blockptr(parent, slot),
|
|
btrfs_node_ptr_generation(parent, slot));
|
|
if (IS_ERR(eb) || !extent_buffer_uptodate(eb)) {
|
|
if (!IS_ERR(eb))
|
|
free_extent_buffer(eb);
|
|
eb = NULL;
|
|
}
|
|
|
|
return eb;
|
|
}
|
|
|
|
/*
|
|
* node level balancing, used to make sure nodes are in proper order for
|
|
* item deletion. We balance from the top down, so we have to make sure
|
|
* that a deletion won't leave an node completely empty later on.
|
|
*/
|
|
static noinline int balance_level(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct extent_buffer *right = NULL;
|
|
struct extent_buffer *mid;
|
|
struct extent_buffer *left = NULL;
|
|
struct extent_buffer *parent = NULL;
|
|
int ret = 0;
|
|
int wret;
|
|
int pslot;
|
|
int orig_slot = path->slots[level];
|
|
u64 orig_ptr;
|
|
|
|
if (level == 0)
|
|
return 0;
|
|
|
|
mid = path->nodes[level];
|
|
|
|
WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
|
|
path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
|
|
WARN_ON(btrfs_header_generation(mid) != trans->transid);
|
|
|
|
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
|
|
|
|
if (level < BTRFS_MAX_LEVEL - 1) {
|
|
parent = path->nodes[level + 1];
|
|
pslot = path->slots[level + 1];
|
|
}
|
|
|
|
/*
|
|
* deal with the case where there is only one pointer in the root
|
|
* by promoting the node below to a root
|
|
*/
|
|
if (!parent) {
|
|
struct extent_buffer *child;
|
|
|
|
if (btrfs_header_nritems(mid) != 1)
|
|
return 0;
|
|
|
|
/* promote the child to a root */
|
|
child = read_node_slot(root, mid, 0);
|
|
if (!child) {
|
|
ret = -EROFS;
|
|
btrfs_std_error(root->fs_info, ret);
|
|
goto enospc;
|
|
}
|
|
|
|
btrfs_tree_lock(child);
|
|
btrfs_set_lock_blocking(child);
|
|
ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
|
|
if (ret) {
|
|
btrfs_tree_unlock(child);
|
|
free_extent_buffer(child);
|
|
goto enospc;
|
|
}
|
|
|
|
tree_mod_log_set_root_pointer(root, child, 1);
|
|
rcu_assign_pointer(root->node, child);
|
|
|
|
add_root_to_dirty_list(root);
|
|
btrfs_tree_unlock(child);
|
|
|
|
path->locks[level] = 0;
|
|
path->nodes[level] = NULL;
|
|
clean_tree_block(trans, root->fs_info, mid);
|
|
btrfs_tree_unlock(mid);
|
|
/* once for the path */
|
|
free_extent_buffer(mid);
|
|
|
|
root_sub_used(root, mid->len);
|
|
btrfs_free_tree_block(trans, root, mid, 0, 1);
|
|
/* once for the root ptr */
|
|
free_extent_buffer_stale(mid);
|
|
return 0;
|
|
}
|
|
if (btrfs_header_nritems(mid) >
|
|
BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
|
|
return 0;
|
|
|
|
left = read_node_slot(root, parent, pslot - 1);
|
|
if (left) {
|
|
btrfs_tree_lock(left);
|
|
btrfs_set_lock_blocking(left);
|
|
wret = btrfs_cow_block(trans, root, left,
|
|
parent, pslot - 1, &left);
|
|
if (wret) {
|
|
ret = wret;
|
|
goto enospc;
|
|
}
|
|
}
|
|
right = read_node_slot(root, parent, pslot + 1);
|
|
if (right) {
|
|
btrfs_tree_lock(right);
|
|
btrfs_set_lock_blocking(right);
|
|
wret = btrfs_cow_block(trans, root, right,
|
|
parent, pslot + 1, &right);
|
|
if (wret) {
|
|
ret = wret;
|
|
goto enospc;
|
|
}
|
|
}
|
|
|
|
/* first, try to make some room in the middle buffer */
|
|
if (left) {
|
|
orig_slot += btrfs_header_nritems(left);
|
|
wret = push_node_left(trans, root, left, mid, 1);
|
|
if (wret < 0)
|
|
ret = wret;
|
|
}
|
|
|
|
/*
|
|
* then try to empty the right most buffer into the middle
|
|
*/
|
|
if (right) {
|
|
wret = push_node_left(trans, root, mid, right, 1);
|
|
if (wret < 0 && wret != -ENOSPC)
|
|
ret = wret;
|
|
if (btrfs_header_nritems(right) == 0) {
|
|
clean_tree_block(trans, root->fs_info, right);
|
|
btrfs_tree_unlock(right);
|
|
del_ptr(root, path, level + 1, pslot + 1);
|
|
root_sub_used(root, right->len);
|
|
btrfs_free_tree_block(trans, root, right, 0, 1);
|
|
free_extent_buffer_stale(right);
|
|
right = NULL;
|
|
} else {
|
|
struct btrfs_disk_key right_key;
|
|
btrfs_node_key(right, &right_key, 0);
|
|
tree_mod_log_set_node_key(root->fs_info, parent,
|
|
pslot + 1, 0);
|
|
btrfs_set_node_key(parent, &right_key, pslot + 1);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
}
|
|
}
|
|
if (btrfs_header_nritems(mid) == 1) {
|
|
/*
|
|
* we're not allowed to leave a node with one item in the
|
|
* tree during a delete. A deletion from lower in the tree
|
|
* could try to delete the only pointer in this node.
|
|
* So, pull some keys from the left.
|
|
* There has to be a left pointer at this point because
|
|
* otherwise we would have pulled some pointers from the
|
|
* right
|
|
*/
|
|
if (!left) {
|
|
ret = -EROFS;
|
|
btrfs_std_error(root->fs_info, ret);
|
|
goto enospc;
|
|
}
|
|
wret = balance_node_right(trans, root, mid, left);
|
|
if (wret < 0) {
|
|
ret = wret;
|
|
goto enospc;
|
|
}
|
|
if (wret == 1) {
|
|
wret = push_node_left(trans, root, left, mid, 1);
|
|
if (wret < 0)
|
|
ret = wret;
|
|
}
|
|
BUG_ON(wret == 1);
|
|
}
|
|
if (btrfs_header_nritems(mid) == 0) {
|
|
clean_tree_block(trans, root->fs_info, mid);
|
|
btrfs_tree_unlock(mid);
|
|
del_ptr(root, path, level + 1, pslot);
|
|
root_sub_used(root, mid->len);
|
|
btrfs_free_tree_block(trans, root, mid, 0, 1);
|
|
free_extent_buffer_stale(mid);
|
|
mid = NULL;
|
|
} else {
|
|
/* update the parent key to reflect our changes */
|
|
struct btrfs_disk_key mid_key;
|
|
btrfs_node_key(mid, &mid_key, 0);
|
|
tree_mod_log_set_node_key(root->fs_info, parent,
|
|
pslot, 0);
|
|
btrfs_set_node_key(parent, &mid_key, pslot);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
}
|
|
|
|
/* update the path */
|
|
if (left) {
|
|
if (btrfs_header_nritems(left) > orig_slot) {
|
|
extent_buffer_get(left);
|
|
/* left was locked after cow */
|
|
path->nodes[level] = left;
|
|
path->slots[level + 1] -= 1;
|
|
path->slots[level] = orig_slot;
|
|
if (mid) {
|
|
btrfs_tree_unlock(mid);
|
|
free_extent_buffer(mid);
|
|
}
|
|
} else {
|
|
orig_slot -= btrfs_header_nritems(left);
|
|
path->slots[level] = orig_slot;
|
|
}
|
|
}
|
|
/* double check we haven't messed things up */
|
|
if (orig_ptr !=
|
|
btrfs_node_blockptr(path->nodes[level], path->slots[level]))
|
|
BUG();
|
|
enospc:
|
|
if (right) {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
if (left) {
|
|
if (path->nodes[level] != left)
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Node balancing for insertion. Here we only split or push nodes around
|
|
* when they are completely full. This is also done top down, so we
|
|
* have to be pessimistic.
|
|
*/
|
|
static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct extent_buffer *right = NULL;
|
|
struct extent_buffer *mid;
|
|
struct extent_buffer *left = NULL;
|
|
struct extent_buffer *parent = NULL;
|
|
int ret = 0;
|
|
int wret;
|
|
int pslot;
|
|
int orig_slot = path->slots[level];
|
|
|
|
if (level == 0)
|
|
return 1;
|
|
|
|
mid = path->nodes[level];
|
|
WARN_ON(btrfs_header_generation(mid) != trans->transid);
|
|
|
|
if (level < BTRFS_MAX_LEVEL - 1) {
|
|
parent = path->nodes[level + 1];
|
|
pslot = path->slots[level + 1];
|
|
}
|
|
|
|
if (!parent)
|
|
return 1;
|
|
|
|
left = read_node_slot(root, parent, pslot - 1);
|
|
|
|
/* first, try to make some room in the middle buffer */
|
|
if (left) {
|
|
u32 left_nr;
|
|
|
|
btrfs_tree_lock(left);
|
|
btrfs_set_lock_blocking(left);
|
|
|
|
left_nr = btrfs_header_nritems(left);
|
|
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
|
|
wret = 1;
|
|
} else {
|
|
ret = btrfs_cow_block(trans, root, left, parent,
|
|
pslot - 1, &left);
|
|
if (ret)
|
|
wret = 1;
|
|
else {
|
|
wret = push_node_left(trans, root,
|
|
left, mid, 0);
|
|
}
|
|
}
|
|
if (wret < 0)
|
|
ret = wret;
|
|
if (wret == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
orig_slot += left_nr;
|
|
btrfs_node_key(mid, &disk_key, 0);
|
|
tree_mod_log_set_node_key(root->fs_info, parent,
|
|
pslot, 0);
|
|
btrfs_set_node_key(parent, &disk_key, pslot);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
if (btrfs_header_nritems(left) > orig_slot) {
|
|
path->nodes[level] = left;
|
|
path->slots[level + 1] -= 1;
|
|
path->slots[level] = orig_slot;
|
|
btrfs_tree_unlock(mid);
|
|
free_extent_buffer(mid);
|
|
} else {
|
|
orig_slot -=
|
|
btrfs_header_nritems(left);
|
|
path->slots[level] = orig_slot;
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
}
|
|
return 0;
|
|
}
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
}
|
|
right = read_node_slot(root, parent, pslot + 1);
|
|
|
|
/*
|
|
* then try to empty the right most buffer into the middle
|
|
*/
|
|
if (right) {
|
|
u32 right_nr;
|
|
|
|
btrfs_tree_lock(right);
|
|
btrfs_set_lock_blocking(right);
|
|
|
|
right_nr = btrfs_header_nritems(right);
|
|
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
|
|
wret = 1;
|
|
} else {
|
|
ret = btrfs_cow_block(trans, root, right,
|
|
parent, pslot + 1,
|
|
&right);
|
|
if (ret)
|
|
wret = 1;
|
|
else {
|
|
wret = balance_node_right(trans, root,
|
|
right, mid);
|
|
}
|
|
}
|
|
if (wret < 0)
|
|
ret = wret;
|
|
if (wret == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_node_key(right, &disk_key, 0);
|
|
tree_mod_log_set_node_key(root->fs_info, parent,
|
|
pslot + 1, 0);
|
|
btrfs_set_node_key(parent, &disk_key, pslot + 1);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
|
|
if (btrfs_header_nritems(mid) <= orig_slot) {
|
|
path->nodes[level] = right;
|
|
path->slots[level + 1] += 1;
|
|
path->slots[level] = orig_slot -
|
|
btrfs_header_nritems(mid);
|
|
btrfs_tree_unlock(mid);
|
|
free_extent_buffer(mid);
|
|
} else {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
return 0;
|
|
}
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* readahead one full node of leaves, finding things that are close
|
|
* to the block in 'slot', and triggering ra on them.
|
|
*/
|
|
static void reada_for_search(struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int level, int slot, u64 objectid)
|
|
{
|
|
struct extent_buffer *node;
|
|
struct btrfs_disk_key disk_key;
|
|
u32 nritems;
|
|
u64 search;
|
|
u64 target;
|
|
u64 nread = 0;
|
|
u64 gen;
|
|
int direction = path->reada;
|
|
struct extent_buffer *eb;
|
|
u32 nr;
|
|
u32 blocksize;
|
|
u32 nscan = 0;
|
|
|
|
if (level != 1)
|
|
return;
|
|
|
|
if (!path->nodes[level])
|
|
return;
|
|
|
|
node = path->nodes[level];
|
|
|
|
search = btrfs_node_blockptr(node, slot);
|
|
blocksize = root->nodesize;
|
|
eb = btrfs_find_tree_block(root->fs_info, search);
|
|
if (eb) {
|
|
free_extent_buffer(eb);
|
|
return;
|
|
}
|
|
|
|
target = search;
|
|
|
|
nritems = btrfs_header_nritems(node);
|
|
nr = slot;
|
|
|
|
while (1) {
|
|
if (direction < 0) {
|
|
if (nr == 0)
|
|
break;
|
|
nr--;
|
|
} else if (direction > 0) {
|
|
nr++;
|
|
if (nr >= nritems)
|
|
break;
|
|
}
|
|
if (path->reada < 0 && objectid) {
|
|
btrfs_node_key(node, &disk_key, nr);
|
|
if (btrfs_disk_key_objectid(&disk_key) != objectid)
|
|
break;
|
|
}
|
|
search = btrfs_node_blockptr(node, nr);
|
|
if ((search <= target && target - search <= 65536) ||
|
|
(search > target && search - target <= 65536)) {
|
|
gen = btrfs_node_ptr_generation(node, nr);
|
|
readahead_tree_block(root, search);
|
|
nread += blocksize;
|
|
}
|
|
nscan++;
|
|
if ((nread > 65536 || nscan > 32))
|
|
break;
|
|
}
|
|
}
|
|
|
|
static noinline void reada_for_balance(struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
int slot;
|
|
int nritems;
|
|
struct extent_buffer *parent;
|
|
struct extent_buffer *eb;
|
|
u64 gen;
|
|
u64 block1 = 0;
|
|
u64 block2 = 0;
|
|
|
|
parent = path->nodes[level + 1];
|
|
if (!parent)
|
|
return;
|
|
|
|
nritems = btrfs_header_nritems(parent);
|
|
slot = path->slots[level + 1];
|
|
|
|
if (slot > 0) {
|
|
block1 = btrfs_node_blockptr(parent, slot - 1);
|
|
gen = btrfs_node_ptr_generation(parent, slot - 1);
|
|
eb = btrfs_find_tree_block(root->fs_info, block1);
|
|
/*
|
|
* if we get -eagain from btrfs_buffer_uptodate, we
|
|
* don't want to return eagain here. That will loop
|
|
* forever
|
|
*/
|
|
if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
|
|
block1 = 0;
|
|
free_extent_buffer(eb);
|
|
}
|
|
if (slot + 1 < nritems) {
|
|
block2 = btrfs_node_blockptr(parent, slot + 1);
|
|
gen = btrfs_node_ptr_generation(parent, slot + 1);
|
|
eb = btrfs_find_tree_block(root->fs_info, block2);
|
|
if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
|
|
block2 = 0;
|
|
free_extent_buffer(eb);
|
|
}
|
|
|
|
if (block1)
|
|
readahead_tree_block(root, block1);
|
|
if (block2)
|
|
readahead_tree_block(root, block2);
|
|
}
|
|
|
|
|
|
/*
|
|
* when we walk down the tree, it is usually safe to unlock the higher layers
|
|
* in the tree. The exceptions are when our path goes through slot 0, because
|
|
* operations on the tree might require changing key pointers higher up in the
|
|
* tree.
|
|
*
|
|
* callers might also have set path->keep_locks, which tells this code to keep
|
|
* the lock if the path points to the last slot in the block. This is part of
|
|
* walking through the tree, and selecting the next slot in the higher block.
|
|
*
|
|
* lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
|
|
* if lowest_unlock is 1, level 0 won't be unlocked
|
|
*/
|
|
static noinline void unlock_up(struct btrfs_path *path, int level,
|
|
int lowest_unlock, int min_write_lock_level,
|
|
int *write_lock_level)
|
|
{
|
|
int i;
|
|
int skip_level = level;
|
|
int no_skips = 0;
|
|
struct extent_buffer *t;
|
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
|
|
if (!path->nodes[i])
|
|
break;
|
|
if (!path->locks[i])
|
|
break;
|
|
if (!no_skips && path->slots[i] == 0) {
|
|
skip_level = i + 1;
|
|
continue;
|
|
}
|
|
if (!no_skips && path->keep_locks) {
|
|
u32 nritems;
|
|
t = path->nodes[i];
|
|
nritems = btrfs_header_nritems(t);
|
|
if (nritems < 1 || path->slots[i] >= nritems - 1) {
|
|
skip_level = i + 1;
|
|
continue;
|
|
}
|
|
}
|
|
if (skip_level < i && i >= lowest_unlock)
|
|
no_skips = 1;
|
|
|
|
t = path->nodes[i];
|
|
if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
|
|
btrfs_tree_unlock_rw(t, path->locks[i]);
|
|
path->locks[i] = 0;
|
|
if (write_lock_level &&
|
|
i > min_write_lock_level &&
|
|
i <= *write_lock_level) {
|
|
*write_lock_level = i - 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This releases any locks held in the path starting at level and
|
|
* going all the way up to the root.
|
|
*
|
|
* btrfs_search_slot will keep the lock held on higher nodes in a few
|
|
* corner cases, such as COW of the block at slot zero in the node. This
|
|
* ignores those rules, and it should only be called when there are no
|
|
* more updates to be done higher up in the tree.
|
|
*/
|
|
noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
|
|
{
|
|
int i;
|
|
|
|
if (path->keep_locks)
|
|
return;
|
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
|
|
if (!path->nodes[i])
|
|
continue;
|
|
if (!path->locks[i])
|
|
continue;
|
|
btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
|
|
path->locks[i] = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* helper function for btrfs_search_slot. The goal is to find a block
|
|
* in cache without setting the path to blocking. If we find the block
|
|
* we return zero and the path is unchanged.
|
|
*
|
|
* If we can't find the block, we set the path blocking and do some
|
|
* reada. -EAGAIN is returned and the search must be repeated.
|
|
*/
|
|
static int
|
|
read_block_for_search(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct btrfs_path *p,
|
|
struct extent_buffer **eb_ret, int level, int slot,
|
|
struct btrfs_key *key, u64 time_seq)
|
|
{
|
|
u64 blocknr;
|
|
u64 gen;
|
|
struct extent_buffer *b = *eb_ret;
|
|
struct extent_buffer *tmp;
|
|
int ret;
|
|
|
|
blocknr = btrfs_node_blockptr(b, slot);
|
|
gen = btrfs_node_ptr_generation(b, slot);
|
|
|
|
tmp = btrfs_find_tree_block(root->fs_info, blocknr);
|
|
if (tmp) {
|
|
/* first we do an atomic uptodate check */
|
|
if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
|
|
*eb_ret = tmp;
|
|
return 0;
|
|
}
|
|
|
|
/* the pages were up to date, but we failed
|
|
* the generation number check. Do a full
|
|
* read for the generation number that is correct.
|
|
* We must do this without dropping locks so
|
|
* we can trust our generation number
|
|
*/
|
|
btrfs_set_path_blocking(p);
|
|
|
|
/* now we're allowed to do a blocking uptodate check */
|
|
ret = btrfs_read_buffer(tmp, gen);
|
|
if (!ret) {
|
|
*eb_ret = tmp;
|
|
return 0;
|
|
}
|
|
free_extent_buffer(tmp);
|
|
btrfs_release_path(p);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* reduce lock contention at high levels
|
|
* of the btree by dropping locks before
|
|
* we read. Don't release the lock on the current
|
|
* level because we need to walk this node to figure
|
|
* out which blocks to read.
|
|
*/
|
|
btrfs_unlock_up_safe(p, level + 1);
|
|
btrfs_set_path_blocking(p);
|
|
|
|
free_extent_buffer(tmp);
|
|
if (p->reada)
|
|
reada_for_search(root, p, level, slot, key->objectid);
|
|
|
|
btrfs_release_path(p);
|
|
|
|
ret = -EAGAIN;
|
|
tmp = read_tree_block(root, blocknr, 0);
|
|
if (!IS_ERR(tmp)) {
|
|
/*
|
|
* If the read above didn't mark this buffer up to date,
|
|
* it will never end up being up to date. Set ret to EIO now
|
|
* and give up so that our caller doesn't loop forever
|
|
* on our EAGAINs.
|
|
*/
|
|
if (!btrfs_buffer_uptodate(tmp, 0, 0))
|
|
ret = -EIO;
|
|
free_extent_buffer(tmp);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper function for btrfs_search_slot. This does all of the checks
|
|
* for node-level blocks and does any balancing required based on
|
|
* the ins_len.
|
|
*
|
|
* If no extra work was required, zero is returned. If we had to
|
|
* drop the path, -EAGAIN is returned and btrfs_search_slot must
|
|
* start over
|
|
*/
|
|
static int
|
|
setup_nodes_for_search(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct btrfs_path *p,
|
|
struct extent_buffer *b, int level, int ins_len,
|
|
int *write_lock_level)
|
|
{
|
|
int ret;
|
|
if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
|
|
BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
|
|
int sret;
|
|
|
|
if (*write_lock_level < level + 1) {
|
|
*write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
btrfs_set_path_blocking(p);
|
|
reada_for_balance(root, p, level);
|
|
sret = split_node(trans, root, p, level);
|
|
btrfs_clear_path_blocking(p, NULL, 0);
|
|
|
|
BUG_ON(sret > 0);
|
|
if (sret) {
|
|
ret = sret;
|
|
goto done;
|
|
}
|
|
b = p->nodes[level];
|
|
} else if (ins_len < 0 && btrfs_header_nritems(b) <
|
|
BTRFS_NODEPTRS_PER_BLOCK(root) / 2) {
|
|
int sret;
|
|
|
|
if (*write_lock_level < level + 1) {
|
|
*write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
btrfs_set_path_blocking(p);
|
|
reada_for_balance(root, p, level);
|
|
sret = balance_level(trans, root, p, level);
|
|
btrfs_clear_path_blocking(p, NULL, 0);
|
|
|
|
if (sret) {
|
|
ret = sret;
|
|
goto done;
|
|
}
|
|
b = p->nodes[level];
|
|
if (!b) {
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
BUG_ON(btrfs_header_nritems(b) == 1);
|
|
}
|
|
return 0;
|
|
|
|
again:
|
|
ret = -EAGAIN;
|
|
done:
|
|
return ret;
|
|
}
|
|
|
|
static void key_search_validate(struct extent_buffer *b,
|
|
struct btrfs_key *key,
|
|
int level)
|
|
{
|
|
#ifdef CONFIG_BTRFS_ASSERT
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_cpu_key_to_disk(&disk_key, key);
|
|
|
|
if (level == 0)
|
|
ASSERT(!memcmp_extent_buffer(b, &disk_key,
|
|
offsetof(struct btrfs_leaf, items[0].key),
|
|
sizeof(disk_key)));
|
|
else
|
|
ASSERT(!memcmp_extent_buffer(b, &disk_key,
|
|
offsetof(struct btrfs_node, ptrs[0].key),
|
|
sizeof(disk_key)));
|
|
#endif
|
|
}
|
|
|
|
static int key_search(struct extent_buffer *b, struct btrfs_key *key,
|
|
int level, int *prev_cmp, int *slot)
|
|
{
|
|
if (*prev_cmp != 0) {
|
|
*prev_cmp = bin_search(b, key, level, slot);
|
|
return *prev_cmp;
|
|
}
|
|
|
|
key_search_validate(b, key, level);
|
|
*slot = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
|
|
u64 iobjectid, u64 ioff, u8 key_type,
|
|
struct btrfs_key *found_key)
|
|
{
|
|
int ret;
|
|
struct btrfs_key key;
|
|
struct extent_buffer *eb;
|
|
|
|
ASSERT(path);
|
|
ASSERT(found_key);
|
|
|
|
key.type = key_type;
|
|
key.objectid = iobjectid;
|
|
key.offset = ioff;
|
|
|
|
ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
eb = path->nodes[0];
|
|
if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
|
|
ret = btrfs_next_leaf(fs_root, path);
|
|
if (ret)
|
|
return ret;
|
|
eb = path->nodes[0];
|
|
}
|
|
|
|
btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
|
|
if (found_key->type != key.type ||
|
|
found_key->objectid != key.objectid)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* look for key in the tree. path is filled in with nodes along the way
|
|
* if key is found, we return zero and you can find the item in the leaf
|
|
* level of the path (level 0)
|
|
*
|
|
* If the key isn't found, the path points to the slot where it should
|
|
* be inserted, and 1 is returned. If there are other errors during the
|
|
* search a negative error number is returned.
|
|
*
|
|
* if ins_len > 0, nodes and leaves will be split as we walk down the
|
|
* tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
|
|
* possible)
|
|
*/
|
|
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_key *key, struct btrfs_path *p, int
|
|
ins_len, int cow)
|
|
{
|
|
struct extent_buffer *b;
|
|
int slot;
|
|
int ret;
|
|
int err;
|
|
int level;
|
|
int lowest_unlock = 1;
|
|
int root_lock;
|
|
/* everything at write_lock_level or lower must be write locked */
|
|
int write_lock_level = 0;
|
|
u8 lowest_level = 0;
|
|
int min_write_lock_level;
|
|
int prev_cmp;
|
|
|
|
lowest_level = p->lowest_level;
|
|
WARN_ON(lowest_level && ins_len > 0);
|
|
WARN_ON(p->nodes[0] != NULL);
|
|
BUG_ON(!cow && ins_len);
|
|
|
|
if (ins_len < 0) {
|
|
lowest_unlock = 2;
|
|
|
|
/* when we are removing items, we might have to go up to level
|
|
* two as we update tree pointers Make sure we keep write
|
|
* for those levels as well
|
|
*/
|
|
write_lock_level = 2;
|
|
} else if (ins_len > 0) {
|
|
/*
|
|
* for inserting items, make sure we have a write lock on
|
|
* level 1 so we can update keys
|
|
*/
|
|
write_lock_level = 1;
|
|
}
|
|
|
|
if (!cow)
|
|
write_lock_level = -1;
|
|
|
|
if (cow && (p->keep_locks || p->lowest_level))
|
|
write_lock_level = BTRFS_MAX_LEVEL;
|
|
|
|
min_write_lock_level = write_lock_level;
|
|
|
|
again:
|
|
prev_cmp = -1;
|
|
/*
|
|
* we try very hard to do read locks on the root
|
|
*/
|
|
root_lock = BTRFS_READ_LOCK;
|
|
level = 0;
|
|
if (p->search_commit_root) {
|
|
/*
|
|
* the commit roots are read only
|
|
* so we always do read locks
|
|
*/
|
|
if (p->need_commit_sem)
|
|
down_read(&root->fs_info->commit_root_sem);
|
|
b = root->commit_root;
|
|
extent_buffer_get(b);
|
|
level = btrfs_header_level(b);
|
|
if (p->need_commit_sem)
|
|
up_read(&root->fs_info->commit_root_sem);
|
|
if (!p->skip_locking)
|
|
btrfs_tree_read_lock(b);
|
|
} else {
|
|
if (p->skip_locking) {
|
|
b = btrfs_root_node(root);
|
|
level = btrfs_header_level(b);
|
|
} else {
|
|
/* we don't know the level of the root node
|
|
* until we actually have it read locked
|
|
*/
|
|
b = btrfs_read_lock_root_node(root);
|
|
level = btrfs_header_level(b);
|
|
if (level <= write_lock_level) {
|
|
/* whoops, must trade for write lock */
|
|
btrfs_tree_read_unlock(b);
|
|
free_extent_buffer(b);
|
|
b = btrfs_lock_root_node(root);
|
|
root_lock = BTRFS_WRITE_LOCK;
|
|
|
|
/* the level might have changed, check again */
|
|
level = btrfs_header_level(b);
|
|
}
|
|
}
|
|
}
|
|
p->nodes[level] = b;
|
|
if (!p->skip_locking)
|
|
p->locks[level] = root_lock;
|
|
|
|
while (b) {
|
|
level = btrfs_header_level(b);
|
|
|
|
/*
|
|
* setup the path here so we can release it under lock
|
|
* contention with the cow code
|
|
*/
|
|
if (cow) {
|
|
/*
|
|
* if we don't really need to cow this block
|
|
* then we don't want to set the path blocking,
|
|
* so we test it here
|
|
*/
|
|
if (!should_cow_block(trans, root, b))
|
|
goto cow_done;
|
|
|
|
/*
|
|
* must have write locks on this node and the
|
|
* parent
|
|
*/
|
|
if (level > write_lock_level ||
|
|
(level + 1 > write_lock_level &&
|
|
level + 1 < BTRFS_MAX_LEVEL &&
|
|
p->nodes[level + 1])) {
|
|
write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
btrfs_set_path_blocking(p);
|
|
err = btrfs_cow_block(trans, root, b,
|
|
p->nodes[level + 1],
|
|
p->slots[level + 1], &b);
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
}
|
|
cow_done:
|
|
p->nodes[level] = b;
|
|
btrfs_clear_path_blocking(p, NULL, 0);
|
|
|
|
/*
|
|
* we have a lock on b and as long as we aren't changing
|
|
* the tree, there is no way to for the items in b to change.
|
|
* It is safe to drop the lock on our parent before we
|
|
* go through the expensive btree search on b.
|
|
*
|
|
* If we're inserting or deleting (ins_len != 0), then we might
|
|
* be changing slot zero, which may require changing the parent.
|
|
* So, we can't drop the lock until after we know which slot
|
|
* we're operating on.
|
|
*/
|
|
if (!ins_len && !p->keep_locks) {
|
|
int u = level + 1;
|
|
|
|
if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
|
|
btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]);
|
|
p->locks[u] = 0;
|
|
}
|
|
}
|
|
|
|
ret = key_search(b, key, level, &prev_cmp, &slot);
|
|
|
|
if (level != 0) {
|
|
int dec = 0;
|
|
if (ret && slot > 0) {
|
|
dec = 1;
|
|
slot -= 1;
|
|
}
|
|
p->slots[level] = slot;
|
|
err = setup_nodes_for_search(trans, root, p, b, level,
|
|
ins_len, &write_lock_level);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
b = p->nodes[level];
|
|
slot = p->slots[level];
|
|
|
|
/*
|
|
* slot 0 is special, if we change the key
|
|
* we have to update the parent pointer
|
|
* which means we must have a write lock
|
|
* on the parent
|
|
*/
|
|
if (slot == 0 && ins_len &&
|
|
write_lock_level < level + 1) {
|
|
write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
unlock_up(p, level, lowest_unlock,
|
|
min_write_lock_level, &write_lock_level);
|
|
|
|
if (level == lowest_level) {
|
|
if (dec)
|
|
p->slots[level]++;
|
|
goto done;
|
|
}
|
|
|
|
err = read_block_for_search(trans, root, p,
|
|
&b, level, slot, key, 0);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
|
|
if (!p->skip_locking) {
|
|
level = btrfs_header_level(b);
|
|
if (level <= write_lock_level) {
|
|
err = btrfs_try_tree_write_lock(b);
|
|
if (!err) {
|
|
btrfs_set_path_blocking(p);
|
|
btrfs_tree_lock(b);
|
|
btrfs_clear_path_blocking(p, b,
|
|
BTRFS_WRITE_LOCK);
|
|
}
|
|
p->locks[level] = BTRFS_WRITE_LOCK;
|
|
} else {
|
|
err = btrfs_tree_read_lock_atomic(b);
|
|
if (!err) {
|
|
btrfs_set_path_blocking(p);
|
|
btrfs_tree_read_lock(b);
|
|
btrfs_clear_path_blocking(p, b,
|
|
BTRFS_READ_LOCK);
|
|
}
|
|
p->locks[level] = BTRFS_READ_LOCK;
|
|
}
|
|
p->nodes[level] = b;
|
|
}
|
|
} else {
|
|
p->slots[level] = slot;
|
|
if (ins_len > 0 &&
|
|
btrfs_leaf_free_space(root, b) < ins_len) {
|
|
if (write_lock_level < 1) {
|
|
write_lock_level = 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
btrfs_set_path_blocking(p);
|
|
err = split_leaf(trans, root, key,
|
|
p, ins_len, ret == 0);
|
|
btrfs_clear_path_blocking(p, NULL, 0);
|
|
|
|
BUG_ON(err > 0);
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
}
|
|
if (!p->search_for_split)
|
|
unlock_up(p, level, lowest_unlock,
|
|
min_write_lock_level, &write_lock_level);
|
|
goto done;
|
|
}
|
|
}
|
|
ret = 1;
|
|
done:
|
|
/*
|
|
* we don't really know what they plan on doing with the path
|
|
* from here on, so for now just mark it as blocking
|
|
*/
|
|
if (!p->leave_spinning)
|
|
btrfs_set_path_blocking(p);
|
|
if (ret < 0 && !p->skip_release_on_error)
|
|
btrfs_release_path(p);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Like btrfs_search_slot, this looks for a key in the given tree. It uses the
|
|
* current state of the tree together with the operations recorded in the tree
|
|
* modification log to search for the key in a previous version of this tree, as
|
|
* denoted by the time_seq parameter.
|
|
*
|
|
* Naturally, there is no support for insert, delete or cow operations.
|
|
*
|
|
* The resulting path and return value will be set up as if we called
|
|
* btrfs_search_slot at that point in time with ins_len and cow both set to 0.
|
|
*/
|
|
int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
|
|
struct btrfs_path *p, u64 time_seq)
|
|
{
|
|
struct extent_buffer *b;
|
|
int slot;
|
|
int ret;
|
|
int err;
|
|
int level;
|
|
int lowest_unlock = 1;
|
|
u8 lowest_level = 0;
|
|
int prev_cmp = -1;
|
|
|
|
lowest_level = p->lowest_level;
|
|
WARN_ON(p->nodes[0] != NULL);
|
|
|
|
if (p->search_commit_root) {
|
|
BUG_ON(time_seq);
|
|
return btrfs_search_slot(NULL, root, key, p, 0, 0);
|
|
}
|
|
|
|
again:
|
|
b = get_old_root(root, time_seq);
|
|
level = btrfs_header_level(b);
|
|
p->locks[level] = BTRFS_READ_LOCK;
|
|
|
|
while (b) {
|
|
level = btrfs_header_level(b);
|
|
p->nodes[level] = b;
|
|
btrfs_clear_path_blocking(p, NULL, 0);
|
|
|
|
/*
|
|
* we have a lock on b and as long as we aren't changing
|
|
* the tree, there is no way to for the items in b to change.
|
|
* It is safe to drop the lock on our parent before we
|
|
* go through the expensive btree search on b.
|
|
*/
|
|
btrfs_unlock_up_safe(p, level + 1);
|
|
|
|
/*
|
|
* Since we can unwind eb's we want to do a real search every
|
|
* time.
|
|
*/
|
|
prev_cmp = -1;
|
|
ret = key_search(b, key, level, &prev_cmp, &slot);
|
|
|
|
if (level != 0) {
|
|
int dec = 0;
|
|
if (ret && slot > 0) {
|
|
dec = 1;
|
|
slot -= 1;
|
|
}
|
|
p->slots[level] = slot;
|
|
unlock_up(p, level, lowest_unlock, 0, NULL);
|
|
|
|
if (level == lowest_level) {
|
|
if (dec)
|
|
p->slots[level]++;
|
|
goto done;
|
|
}
|
|
|
|
err = read_block_for_search(NULL, root, p, &b, level,
|
|
slot, key, time_seq);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
|
|
level = btrfs_header_level(b);
|
|
err = btrfs_tree_read_lock_atomic(b);
|
|
if (!err) {
|
|
btrfs_set_path_blocking(p);
|
|
btrfs_tree_read_lock(b);
|
|
btrfs_clear_path_blocking(p, b,
|
|
BTRFS_READ_LOCK);
|
|
}
|
|
b = tree_mod_log_rewind(root->fs_info, p, b, time_seq);
|
|
if (!b) {
|
|
ret = -ENOMEM;
|
|
goto done;
|
|
}
|
|
p->locks[level] = BTRFS_READ_LOCK;
|
|
p->nodes[level] = b;
|
|
} else {
|
|
p->slots[level] = slot;
|
|
unlock_up(p, level, lowest_unlock, 0, NULL);
|
|
goto done;
|
|
}
|
|
}
|
|
ret = 1;
|
|
done:
|
|
if (!p->leave_spinning)
|
|
btrfs_set_path_blocking(p);
|
|
if (ret < 0)
|
|
btrfs_release_path(p);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper to use instead of search slot if no exact match is needed but
|
|
* instead the next or previous item should be returned.
|
|
* When find_higher is true, the next higher item is returned, the next lower
|
|
* otherwise.
|
|
* When return_any and find_higher are both true, and no higher item is found,
|
|
* return the next lower instead.
|
|
* When return_any is true and find_higher is false, and no lower item is found,
|
|
* return the next higher instead.
|
|
* It returns 0 if any item is found, 1 if none is found (tree empty), and
|
|
* < 0 on error
|
|
*/
|
|
int btrfs_search_slot_for_read(struct btrfs_root *root,
|
|
struct btrfs_key *key, struct btrfs_path *p,
|
|
int find_higher, int return_any)
|
|
{
|
|
int ret;
|
|
struct extent_buffer *leaf;
|
|
|
|
again:
|
|
ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
|
|
if (ret <= 0)
|
|
return ret;
|
|
/*
|
|
* a return value of 1 means the path is at the position where the
|
|
* item should be inserted. Normally this is the next bigger item,
|
|
* but in case the previous item is the last in a leaf, path points
|
|
* to the first free slot in the previous leaf, i.e. at an invalid
|
|
* item.
|
|
*/
|
|
leaf = p->nodes[0];
|
|
|
|
if (find_higher) {
|
|
if (p->slots[0] >= btrfs_header_nritems(leaf)) {
|
|
ret = btrfs_next_leaf(root, p);
|
|
if (ret <= 0)
|
|
return ret;
|
|
if (!return_any)
|
|
return 1;
|
|
/*
|
|
* no higher item found, return the next
|
|
* lower instead
|
|
*/
|
|
return_any = 0;
|
|
find_higher = 0;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
} else {
|
|
if (p->slots[0] == 0) {
|
|
ret = btrfs_prev_leaf(root, p);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (!ret) {
|
|
leaf = p->nodes[0];
|
|
if (p->slots[0] == btrfs_header_nritems(leaf))
|
|
p->slots[0]--;
|
|
return 0;
|
|
}
|
|
if (!return_any)
|
|
return 1;
|
|
/*
|
|
* no lower item found, return the next
|
|
* higher instead
|
|
*/
|
|
return_any = 0;
|
|
find_higher = 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
} else {
|
|
--p->slots[0];
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* adjust the pointers going up the tree, starting at level
|
|
* making sure the right key of each node is points to 'key'.
|
|
* This is used after shifting pointers to the left, so it stops
|
|
* fixing up pointers when a given leaf/node is not in slot 0 of the
|
|
* higher levels
|
|
*
|
|
*/
|
|
static void fixup_low_keys(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
struct btrfs_disk_key *key, int level)
|
|
{
|
|
int i;
|
|
struct extent_buffer *t;
|
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
|
|
int tslot = path->slots[i];
|
|
if (!path->nodes[i])
|
|
break;
|
|
t = path->nodes[i];
|
|
tree_mod_log_set_node_key(fs_info, t, tslot, 1);
|
|
btrfs_set_node_key(t, key, tslot);
|
|
btrfs_mark_buffer_dirty(path->nodes[i]);
|
|
if (tslot != 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* update item key.
|
|
*
|
|
* This function isn't completely safe. It's the caller's responsibility
|
|
* that the new key won't break the order
|
|
*/
|
|
void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *new_key)
|
|
{
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *eb;
|
|
int slot;
|
|
|
|
eb = path->nodes[0];
|
|
slot = path->slots[0];
|
|
if (slot > 0) {
|
|
btrfs_item_key(eb, &disk_key, slot - 1);
|
|
BUG_ON(comp_keys(&disk_key, new_key) >= 0);
|
|
}
|
|
if (slot < btrfs_header_nritems(eb) - 1) {
|
|
btrfs_item_key(eb, &disk_key, slot + 1);
|
|
BUG_ON(comp_keys(&disk_key, new_key) <= 0);
|
|
}
|
|
|
|
btrfs_cpu_key_to_disk(&disk_key, new_key);
|
|
btrfs_set_item_key(eb, &disk_key, slot);
|
|
btrfs_mark_buffer_dirty(eb);
|
|
if (slot == 0)
|
|
fixup_low_keys(fs_info, path, &disk_key, 1);
|
|
}
|
|
|
|
/*
|
|
* try to push data from one node into the next node left in the
|
|
* tree.
|
|
*
|
|
* returns 0 if some ptrs were pushed left, < 0 if there was some horrible
|
|
* error, and > 0 if there was no room in the left hand block.
|
|
*/
|
|
static int push_node_left(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct extent_buffer *dst,
|
|
struct extent_buffer *src, int empty)
|
|
{
|
|
int push_items = 0;
|
|
int src_nritems;
|
|
int dst_nritems;
|
|
int ret = 0;
|
|
|
|
src_nritems = btrfs_header_nritems(src);
|
|
dst_nritems = btrfs_header_nritems(dst);
|
|
push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
|
|
WARN_ON(btrfs_header_generation(src) != trans->transid);
|
|
WARN_ON(btrfs_header_generation(dst) != trans->transid);
|
|
|
|
if (!empty && src_nritems <= 8)
|
|
return 1;
|
|
|
|
if (push_items <= 0)
|
|
return 1;
|
|
|
|
if (empty) {
|
|
push_items = min(src_nritems, push_items);
|
|
if (push_items < src_nritems) {
|
|
/* leave at least 8 pointers in the node if
|
|
* we aren't going to empty it
|
|
*/
|
|
if (src_nritems - push_items < 8) {
|
|
if (push_items <= 8)
|
|
return 1;
|
|
push_items -= 8;
|
|
}
|
|
}
|
|
} else
|
|
push_items = min(src_nritems - 8, push_items);
|
|
|
|
ret = tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
|
|
push_items);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, root, ret);
|
|
return ret;
|
|
}
|
|
copy_extent_buffer(dst, src,
|
|
btrfs_node_key_ptr_offset(dst_nritems),
|
|
btrfs_node_key_ptr_offset(0),
|
|
push_items * sizeof(struct btrfs_key_ptr));
|
|
|
|
if (push_items < src_nritems) {
|
|
/*
|
|
* don't call tree_mod_log_eb_move here, key removal was already
|
|
* fully logged by tree_mod_log_eb_copy above.
|
|
*/
|
|
memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
|
|
btrfs_node_key_ptr_offset(push_items),
|
|
(src_nritems - push_items) *
|
|
sizeof(struct btrfs_key_ptr));
|
|
}
|
|
btrfs_set_header_nritems(src, src_nritems - push_items);
|
|
btrfs_set_header_nritems(dst, dst_nritems + push_items);
|
|
btrfs_mark_buffer_dirty(src);
|
|
btrfs_mark_buffer_dirty(dst);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* try to push data from one node into the next node right in the
|
|
* tree.
|
|
*
|
|
* returns 0 if some ptrs were pushed, < 0 if there was some horrible
|
|
* error, and > 0 if there was no room in the right hand block.
|
|
*
|
|
* this will only push up to 1/2 the contents of the left node over
|
|
*/
|
|
static int balance_node_right(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct extent_buffer *dst,
|
|
struct extent_buffer *src)
|
|
{
|
|
int push_items = 0;
|
|
int max_push;
|
|
int src_nritems;
|
|
int dst_nritems;
|
|
int ret = 0;
|
|
|
|
WARN_ON(btrfs_header_generation(src) != trans->transid);
|
|
WARN_ON(btrfs_header_generation(dst) != trans->transid);
|
|
|
|
src_nritems = btrfs_header_nritems(src);
|
|
dst_nritems = btrfs_header_nritems(dst);
|
|
push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
|
|
if (push_items <= 0)
|
|
return 1;
|
|
|
|
if (src_nritems < 4)
|
|
return 1;
|
|
|
|
max_push = src_nritems / 2 + 1;
|
|
/* don't try to empty the node */
|
|
if (max_push >= src_nritems)
|
|
return 1;
|
|
|
|
if (max_push < push_items)
|
|
push_items = max_push;
|
|
|
|
tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems);
|
|
memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
|
|
btrfs_node_key_ptr_offset(0),
|
|
(dst_nritems) *
|
|
sizeof(struct btrfs_key_ptr));
|
|
|
|
ret = tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
|
|
src_nritems - push_items, push_items);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, root, ret);
|
|
return ret;
|
|
}
|
|
copy_extent_buffer(dst, src,
|
|
btrfs_node_key_ptr_offset(0),
|
|
btrfs_node_key_ptr_offset(src_nritems - push_items),
|
|
push_items * sizeof(struct btrfs_key_ptr));
|
|
|
|
btrfs_set_header_nritems(src, src_nritems - push_items);
|
|
btrfs_set_header_nritems(dst, dst_nritems + push_items);
|
|
|
|
btrfs_mark_buffer_dirty(src);
|
|
btrfs_mark_buffer_dirty(dst);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper function to insert a new root level in the tree.
|
|
* A new node is allocated, and a single item is inserted to
|
|
* point to the existing root
|
|
*
|
|
* returns zero on success or < 0 on failure.
|
|
*/
|
|
static noinline int insert_new_root(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
u64 lower_gen;
|
|
struct extent_buffer *lower;
|
|
struct extent_buffer *c;
|
|
struct extent_buffer *old;
|
|
struct btrfs_disk_key lower_key;
|
|
|
|
BUG_ON(path->nodes[level]);
|
|
BUG_ON(path->nodes[level-1] != root->node);
|
|
|
|
lower = path->nodes[level-1];
|
|
if (level == 1)
|
|
btrfs_item_key(lower, &lower_key, 0);
|
|
else
|
|
btrfs_node_key(lower, &lower_key, 0);
|
|
|
|
c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
|
|
&lower_key, level, root->node->start, 0);
|
|
if (IS_ERR(c))
|
|
return PTR_ERR(c);
|
|
|
|
root_add_used(root, root->nodesize);
|
|
|
|
memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
|
|
btrfs_set_header_nritems(c, 1);
|
|
btrfs_set_header_level(c, level);
|
|
btrfs_set_header_bytenr(c, c->start);
|
|
btrfs_set_header_generation(c, trans->transid);
|
|
btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
|
|
btrfs_set_header_owner(c, root->root_key.objectid);
|
|
|
|
write_extent_buffer(c, root->fs_info->fsid, btrfs_header_fsid(),
|
|
BTRFS_FSID_SIZE);
|
|
|
|
write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
|
|
btrfs_header_chunk_tree_uuid(c), BTRFS_UUID_SIZE);
|
|
|
|
btrfs_set_node_key(c, &lower_key, 0);
|
|
btrfs_set_node_blockptr(c, 0, lower->start);
|
|
lower_gen = btrfs_header_generation(lower);
|
|
WARN_ON(lower_gen != trans->transid);
|
|
|
|
btrfs_set_node_ptr_generation(c, 0, lower_gen);
|
|
|
|
btrfs_mark_buffer_dirty(c);
|
|
|
|
old = root->node;
|
|
tree_mod_log_set_root_pointer(root, c, 0);
|
|
rcu_assign_pointer(root->node, c);
|
|
|
|
/* the super has an extra ref to root->node */
|
|
free_extent_buffer(old);
|
|
|
|
add_root_to_dirty_list(root);
|
|
extent_buffer_get(c);
|
|
path->nodes[level] = c;
|
|
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
|
|
path->slots[level] = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* worker function to insert a single pointer in a node.
|
|
* the node should have enough room for the pointer already
|
|
*
|
|
* slot and level indicate where you want the key to go, and
|
|
* blocknr is the block the key points to.
|
|
*/
|
|
static void insert_ptr(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct btrfs_path *path,
|
|
struct btrfs_disk_key *key, u64 bytenr,
|
|
int slot, int level)
|
|
{
|
|
struct extent_buffer *lower;
|
|
int nritems;
|
|
int ret;
|
|
|
|
BUG_ON(!path->nodes[level]);
|
|
btrfs_assert_tree_locked(path->nodes[level]);
|
|
lower = path->nodes[level];
|
|
nritems = btrfs_header_nritems(lower);
|
|
BUG_ON(slot > nritems);
|
|
BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root));
|
|
if (slot != nritems) {
|
|
if (level)
|
|
tree_mod_log_eb_move(root->fs_info, lower, slot + 1,
|
|
slot, nritems - slot);
|
|
memmove_extent_buffer(lower,
|
|
btrfs_node_key_ptr_offset(slot + 1),
|
|
btrfs_node_key_ptr_offset(slot),
|
|
(nritems - slot) * sizeof(struct btrfs_key_ptr));
|
|
}
|
|
if (level) {
|
|
ret = tree_mod_log_insert_key(root->fs_info, lower, slot,
|
|
MOD_LOG_KEY_ADD, GFP_NOFS);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
btrfs_set_node_key(lower, key, slot);
|
|
btrfs_set_node_blockptr(lower, slot, bytenr);
|
|
WARN_ON(trans->transid == 0);
|
|
btrfs_set_node_ptr_generation(lower, slot, trans->transid);
|
|
btrfs_set_header_nritems(lower, nritems + 1);
|
|
btrfs_mark_buffer_dirty(lower);
|
|
}
|
|
|
|
/*
|
|
* split the node at the specified level in path in two.
|
|
* The path is corrected to point to the appropriate node after the split
|
|
*
|
|
* Before splitting this tries to make some room in the node by pushing
|
|
* left and right, if either one works, it returns right away.
|
|
*
|
|
* returns 0 on success and < 0 on failure
|
|
*/
|
|
static noinline int split_node(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct extent_buffer *c;
|
|
struct extent_buffer *split;
|
|
struct btrfs_disk_key disk_key;
|
|
int mid;
|
|
int ret;
|
|
u32 c_nritems;
|
|
|
|
c = path->nodes[level];
|
|
WARN_ON(btrfs_header_generation(c) != trans->transid);
|
|
if (c == root->node) {
|
|
/*
|
|
* trying to split the root, lets make a new one
|
|
*
|
|
* tree mod log: We don't log_removal old root in
|
|
* insert_new_root, because that root buffer will be kept as a
|
|
* normal node. We are going to log removal of half of the
|
|
* elements below with tree_mod_log_eb_copy. We're holding a
|
|
* tree lock on the buffer, which is why we cannot race with
|
|
* other tree_mod_log users.
|
|
*/
|
|
ret = insert_new_root(trans, root, path, level + 1);
|
|
if (ret)
|
|
return ret;
|
|
} else {
|
|
ret = push_nodes_for_insert(trans, root, path, level);
|
|
c = path->nodes[level];
|
|
if (!ret && btrfs_header_nritems(c) <
|
|
BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
|
|
return 0;
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
c_nritems = btrfs_header_nritems(c);
|
|
mid = (c_nritems + 1) / 2;
|
|
btrfs_node_key(c, &disk_key, mid);
|
|
|
|
split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
|
|
&disk_key, level, c->start, 0);
|
|
if (IS_ERR(split))
|
|
return PTR_ERR(split);
|
|
|
|
root_add_used(root, root->nodesize);
|
|
|
|
memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
|
|
btrfs_set_header_level(split, btrfs_header_level(c));
|
|
btrfs_set_header_bytenr(split, split->start);
|
|
btrfs_set_header_generation(split, trans->transid);
|
|
btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
|
|
btrfs_set_header_owner(split, root->root_key.objectid);
|
|
write_extent_buffer(split, root->fs_info->fsid,
|
|
btrfs_header_fsid(), BTRFS_FSID_SIZE);
|
|
write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
|
|
btrfs_header_chunk_tree_uuid(split),
|
|
BTRFS_UUID_SIZE);
|
|
|
|
ret = tree_mod_log_eb_copy(root->fs_info, split, c, 0,
|
|
mid, c_nritems - mid);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, root, ret);
|
|
return ret;
|
|
}
|
|
copy_extent_buffer(split, c,
|
|
btrfs_node_key_ptr_offset(0),
|
|
btrfs_node_key_ptr_offset(mid),
|
|
(c_nritems - mid) * sizeof(struct btrfs_key_ptr));
|
|
btrfs_set_header_nritems(split, c_nritems - mid);
|
|
btrfs_set_header_nritems(c, mid);
|
|
ret = 0;
|
|
|
|
btrfs_mark_buffer_dirty(c);
|
|
btrfs_mark_buffer_dirty(split);
|
|
|
|
insert_ptr(trans, root, path, &disk_key, split->start,
|
|
path->slots[level + 1] + 1, level + 1);
|
|
|
|
if (path->slots[level] >= mid) {
|
|
path->slots[level] -= mid;
|
|
btrfs_tree_unlock(c);
|
|
free_extent_buffer(c);
|
|
path->nodes[level] = split;
|
|
path->slots[level + 1] += 1;
|
|
} else {
|
|
btrfs_tree_unlock(split);
|
|
free_extent_buffer(split);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* how many bytes are required to store the items in a leaf. start
|
|
* and nr indicate which items in the leaf to check. This totals up the
|
|
* space used both by the item structs and the item data
|
|
*/
|
|
static int leaf_space_used(struct extent_buffer *l, int start, int nr)
|
|
{
|
|
struct btrfs_item *start_item;
|
|
struct btrfs_item *end_item;
|
|
struct btrfs_map_token token;
|
|
int data_len;
|
|
int nritems = btrfs_header_nritems(l);
|
|
int end = min(nritems, start + nr) - 1;
|
|
|
|
if (!nr)
|
|
return 0;
|
|
btrfs_init_map_token(&token);
|
|
start_item = btrfs_item_nr(start);
|
|
end_item = btrfs_item_nr(end);
|
|
data_len = btrfs_token_item_offset(l, start_item, &token) +
|
|
btrfs_token_item_size(l, start_item, &token);
|
|
data_len = data_len - btrfs_token_item_offset(l, end_item, &token);
|
|
data_len += sizeof(struct btrfs_item) * nr;
|
|
WARN_ON(data_len < 0);
|
|
return data_len;
|
|
}
|
|
|
|
/*
|
|
* The space between the end of the leaf items and
|
|
* the start of the leaf data. IOW, how much room
|
|
* the leaf has left for both items and data
|
|
*/
|
|
noinline int btrfs_leaf_free_space(struct btrfs_root *root,
|
|
struct extent_buffer *leaf)
|
|
{
|
|
int nritems = btrfs_header_nritems(leaf);
|
|
int ret;
|
|
ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
|
|
if (ret < 0) {
|
|
btrfs_crit(root->fs_info,
|
|
"leaf free space ret %d, leaf data size %lu, used %d nritems %d",
|
|
ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
|
|
leaf_space_used(leaf, 0, nritems), nritems);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* min slot controls the lowest index we're willing to push to the
|
|
* right. We'll push up to and including min_slot, but no lower
|
|
*/
|
|
static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int data_size, int empty,
|
|
struct extent_buffer *right,
|
|
int free_space, u32 left_nritems,
|
|
u32 min_slot)
|
|
{
|
|
struct extent_buffer *left = path->nodes[0];
|
|
struct extent_buffer *upper = path->nodes[1];
|
|
struct btrfs_map_token token;
|
|
struct btrfs_disk_key disk_key;
|
|
int slot;
|
|
u32 i;
|
|
int push_space = 0;
|
|
int push_items = 0;
|
|
struct btrfs_item *item;
|
|
u32 nr;
|
|
u32 right_nritems;
|
|
u32 data_end;
|
|
u32 this_item_size;
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
if (empty)
|
|
nr = 0;
|
|
else
|
|
nr = max_t(u32, 1, min_slot);
|
|
|
|
if (path->slots[0] >= left_nritems)
|
|
push_space += data_size;
|
|
|
|
slot = path->slots[1];
|
|
i = left_nritems - 1;
|
|
while (i >= nr) {
|
|
item = btrfs_item_nr(i);
|
|
|
|
if (!empty && push_items > 0) {
|
|
if (path->slots[0] > i)
|
|
break;
|
|
if (path->slots[0] == i) {
|
|
int space = btrfs_leaf_free_space(root, left);
|
|
if (space + push_space * 2 > free_space)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (path->slots[0] == i)
|
|
push_space += data_size;
|
|
|
|
this_item_size = btrfs_item_size(left, item);
|
|
if (this_item_size + sizeof(*item) + push_space > free_space)
|
|
break;
|
|
|
|
push_items++;
|
|
push_space += this_item_size + sizeof(*item);
|
|
if (i == 0)
|
|
break;
|
|
i--;
|
|
}
|
|
|
|
if (push_items == 0)
|
|
goto out_unlock;
|
|
|
|
WARN_ON(!empty && push_items == left_nritems);
|
|
|
|
/* push left to right */
|
|
right_nritems = btrfs_header_nritems(right);
|
|
|
|
push_space = btrfs_item_end_nr(left, left_nritems - push_items);
|
|
push_space -= leaf_data_end(root, left);
|
|
|
|
/* make room in the right data area */
|
|
data_end = leaf_data_end(root, right);
|
|
memmove_extent_buffer(right,
|
|
btrfs_leaf_data(right) + data_end - push_space,
|
|
btrfs_leaf_data(right) + data_end,
|
|
BTRFS_LEAF_DATA_SIZE(root) - data_end);
|
|
|
|
/* copy from the left data area */
|
|
copy_extent_buffer(right, left, btrfs_leaf_data(right) +
|
|
BTRFS_LEAF_DATA_SIZE(root) - push_space,
|
|
btrfs_leaf_data(left) + leaf_data_end(root, left),
|
|
push_space);
|
|
|
|
memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
|
|
btrfs_item_nr_offset(0),
|
|
right_nritems * sizeof(struct btrfs_item));
|
|
|
|
/* copy the items from left to right */
|
|
copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
|
|
btrfs_item_nr_offset(left_nritems - push_items),
|
|
push_items * sizeof(struct btrfs_item));
|
|
|
|
/* update the item pointers */
|
|
right_nritems += push_items;
|
|
btrfs_set_header_nritems(right, right_nritems);
|
|
push_space = BTRFS_LEAF_DATA_SIZE(root);
|
|
for (i = 0; i < right_nritems; i++) {
|
|
item = btrfs_item_nr(i);
|
|
push_space -= btrfs_token_item_size(right, item, &token);
|
|
btrfs_set_token_item_offset(right, item, push_space, &token);
|
|
}
|
|
|
|
left_nritems -= push_items;
|
|
btrfs_set_header_nritems(left, left_nritems);
|
|
|
|
if (left_nritems)
|
|
btrfs_mark_buffer_dirty(left);
|
|
else
|
|
clean_tree_block(trans, root->fs_info, left);
|
|
|
|
btrfs_mark_buffer_dirty(right);
|
|
|
|
btrfs_item_key(right, &disk_key, 0);
|
|
btrfs_set_node_key(upper, &disk_key, slot + 1);
|
|
btrfs_mark_buffer_dirty(upper);
|
|
|
|
/* then fixup the leaf pointer in the path */
|
|
if (path->slots[0] >= left_nritems) {
|
|
path->slots[0] -= left_nritems;
|
|
if (btrfs_header_nritems(path->nodes[0]) == 0)
|
|
clean_tree_block(trans, root->fs_info, path->nodes[0]);
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[1] += 1;
|
|
} else {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
return 0;
|
|
|
|
out_unlock:
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* push some data in the path leaf to the right, trying to free up at
|
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise
|
|
*
|
|
* returns 1 if the push failed because the other node didn't have enough
|
|
* room, 0 if everything worked out and < 0 if there were major errors.
|
|
*
|
|
* this will push starting from min_slot to the end of the leaf. It won't
|
|
* push any slot lower than min_slot
|
|
*/
|
|
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_path *path,
|
|
int min_data_size, int data_size,
|
|
int empty, u32 min_slot)
|
|
{
|
|
struct extent_buffer *left = path->nodes[0];
|
|
struct extent_buffer *right;
|
|
struct extent_buffer *upper;
|
|
int slot;
|
|
int free_space;
|
|
u32 left_nritems;
|
|
int ret;
|
|
|
|
if (!path->nodes[1])
|
|
return 1;
|
|
|
|
slot = path->slots[1];
|
|
upper = path->nodes[1];
|
|
if (slot >= btrfs_header_nritems(upper) - 1)
|
|
return 1;
|
|
|
|
btrfs_assert_tree_locked(path->nodes[1]);
|
|
|
|
right = read_node_slot(root, upper, slot + 1);
|
|
if (right == NULL)
|
|
return 1;
|
|
|
|
btrfs_tree_lock(right);
|
|
btrfs_set_lock_blocking(right);
|
|
|
|
free_space = btrfs_leaf_free_space(root, right);
|
|
if (free_space < data_size)
|
|
goto out_unlock;
|
|
|
|
/* cow and double check */
|
|
ret = btrfs_cow_block(trans, root, right, upper,
|
|
slot + 1, &right);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
free_space = btrfs_leaf_free_space(root, right);
|
|
if (free_space < data_size)
|
|
goto out_unlock;
|
|
|
|
left_nritems = btrfs_header_nritems(left);
|
|
if (left_nritems == 0)
|
|
goto out_unlock;
|
|
|
|
if (path->slots[0] == left_nritems && !empty) {
|
|
/* Key greater than all keys in the leaf, right neighbor has
|
|
* enough room for it and we're not emptying our leaf to delete
|
|
* it, therefore use right neighbor to insert the new item and
|
|
* no need to touch/dirty our left leaft. */
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
path->nodes[0] = right;
|
|
path->slots[0] = 0;
|
|
path->slots[1]++;
|
|
return 0;
|
|
}
|
|
|
|
return __push_leaf_right(trans, root, path, min_data_size, empty,
|
|
right, free_space, left_nritems, min_slot);
|
|
out_unlock:
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* push some data in the path leaf to the left, trying to free up at
|
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise
|
|
*
|
|
* max_slot can put a limit on how far into the leaf we'll push items. The
|
|
* item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
|
|
* items
|
|
*/
|
|
static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int data_size,
|
|
int empty, struct extent_buffer *left,
|
|
int free_space, u32 right_nritems,
|
|
u32 max_slot)
|
|
{
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *right = path->nodes[0];
|
|
int i;
|
|
int push_space = 0;
|
|
int push_items = 0;
|
|
struct btrfs_item *item;
|
|
u32 old_left_nritems;
|
|
u32 nr;
|
|
int ret = 0;
|
|
u32 this_item_size;
|
|
u32 old_left_item_size;
|
|
struct btrfs_map_token token;
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
if (empty)
|
|
nr = min(right_nritems, max_slot);
|
|
else
|
|
nr = min(right_nritems - 1, max_slot);
|
|
|
|
for (i = 0; i < nr; i++) {
|
|
item = btrfs_item_nr(i);
|
|
|
|
if (!empty && push_items > 0) {
|
|
if (path->slots[0] < i)
|
|
break;
|
|
if (path->slots[0] == i) {
|
|
int space = btrfs_leaf_free_space(root, right);
|
|
if (space + push_space * 2 > free_space)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (path->slots[0] == i)
|
|
push_space += data_size;
|
|
|
|
this_item_size = btrfs_item_size(right, item);
|
|
if (this_item_size + sizeof(*item) + push_space > free_space)
|
|
break;
|
|
|
|
push_items++;
|
|
push_space += this_item_size + sizeof(*item);
|
|
}
|
|
|
|
if (push_items == 0) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
WARN_ON(!empty && push_items == btrfs_header_nritems(right));
|
|
|
|
/* push data from right to left */
|
|
copy_extent_buffer(left, right,
|
|
btrfs_item_nr_offset(btrfs_header_nritems(left)),
|
|
btrfs_item_nr_offset(0),
|
|
push_items * sizeof(struct btrfs_item));
|
|
|
|
push_space = BTRFS_LEAF_DATA_SIZE(root) -
|
|
btrfs_item_offset_nr(right, push_items - 1);
|
|
|
|
copy_extent_buffer(left, right, btrfs_leaf_data(left) +
|
|
leaf_data_end(root, left) - push_space,
|
|
btrfs_leaf_data(right) +
|
|
btrfs_item_offset_nr(right, push_items - 1),
|
|
push_space);
|
|
old_left_nritems = btrfs_header_nritems(left);
|
|
BUG_ON(old_left_nritems <= 0);
|
|
|
|
old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
|
|
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
|
|
u32 ioff;
|
|
|
|
item = btrfs_item_nr(i);
|
|
|
|
ioff = btrfs_token_item_offset(left, item, &token);
|
|
btrfs_set_token_item_offset(left, item,
|
|
ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size),
|
|
&token);
|
|
}
|
|
btrfs_set_header_nritems(left, old_left_nritems + push_items);
|
|
|
|
/* fixup right node */
|
|
if (push_items > right_nritems)
|
|
WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
|
|
right_nritems);
|
|
|
|
if (push_items < right_nritems) {
|
|
push_space = btrfs_item_offset_nr(right, push_items - 1) -
|
|
leaf_data_end(root, right);
|
|
memmove_extent_buffer(right, btrfs_leaf_data(right) +
|
|
BTRFS_LEAF_DATA_SIZE(root) - push_space,
|
|
btrfs_leaf_data(right) +
|
|
leaf_data_end(root, right), push_space);
|
|
|
|
memmove_extent_buffer(right, btrfs_item_nr_offset(0),
|
|
btrfs_item_nr_offset(push_items),
|
|
(btrfs_header_nritems(right) - push_items) *
|
|
sizeof(struct btrfs_item));
|
|
}
|
|
right_nritems -= push_items;
|
|
btrfs_set_header_nritems(right, right_nritems);
|
|
push_space = BTRFS_LEAF_DATA_SIZE(root);
|
|
for (i = 0; i < right_nritems; i++) {
|
|
item = btrfs_item_nr(i);
|
|
|
|
push_space = push_space - btrfs_token_item_size(right,
|
|
item, &token);
|
|
btrfs_set_token_item_offset(right, item, push_space, &token);
|
|
}
|
|
|
|
btrfs_mark_buffer_dirty(left);
|
|
if (right_nritems)
|
|
btrfs_mark_buffer_dirty(right);
|
|
else
|
|
clean_tree_block(trans, root->fs_info, right);
|
|
|
|
btrfs_item_key(right, &disk_key, 0);
|
|
fixup_low_keys(root->fs_info, path, &disk_key, 1);
|
|
|
|
/* then fixup the leaf pointer in the path */
|
|
if (path->slots[0] < push_items) {
|
|
path->slots[0] += old_left_nritems;
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = left;
|
|
path->slots[1] -= 1;
|
|
} else {
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
path->slots[0] -= push_items;
|
|
}
|
|
BUG_ON(path->slots[0] < 0);
|
|
return ret;
|
|
out:
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* push some data in the path leaf to the left, trying to free up at
|
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise
|
|
*
|
|
* max_slot can put a limit on how far into the leaf we'll push items. The
|
|
* item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
|
|
* items
|
|
*/
|
|
static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_path *path, int min_data_size,
|
|
int data_size, int empty, u32 max_slot)
|
|
{
|
|
struct extent_buffer *right = path->nodes[0];
|
|
struct extent_buffer *left;
|
|
int slot;
|
|
int free_space;
|
|
u32 right_nritems;
|
|
int ret = 0;
|
|
|
|
slot = path->slots[1];
|
|
if (slot == 0)
|
|
return 1;
|
|
if (!path->nodes[1])
|
|
return 1;
|
|
|
|
right_nritems = btrfs_header_nritems(right);
|
|
if (right_nritems == 0)
|
|
return 1;
|
|
|
|
btrfs_assert_tree_locked(path->nodes[1]);
|
|
|
|
left = read_node_slot(root, path->nodes[1], slot - 1);
|
|
if (left == NULL)
|
|
return 1;
|
|
|
|
btrfs_tree_lock(left);
|
|
btrfs_set_lock_blocking(left);
|
|
|
|
free_space = btrfs_leaf_free_space(root, left);
|
|
if (free_space < data_size) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
|
|
/* cow and double check */
|
|
ret = btrfs_cow_block(trans, root, left,
|
|
path->nodes[1], slot - 1, &left);
|
|
if (ret) {
|
|
/* we hit -ENOSPC, but it isn't fatal here */
|
|
if (ret == -ENOSPC)
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
|
|
free_space = btrfs_leaf_free_space(root, left);
|
|
if (free_space < data_size) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
|
|
return __push_leaf_left(trans, root, path, min_data_size,
|
|
empty, left, free_space, right_nritems,
|
|
max_slot);
|
|
out:
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* split the path's leaf in two, making sure there is at least data_size
|
|
* available for the resulting leaf level of the path.
|
|
*/
|
|
static noinline void copy_for_split(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct extent_buffer *l,
|
|
struct extent_buffer *right,
|
|
int slot, int mid, int nritems)
|
|
{
|
|
int data_copy_size;
|
|
int rt_data_off;
|
|
int i;
|
|
struct btrfs_disk_key disk_key;
|
|
struct btrfs_map_token token;
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
nritems = nritems - mid;
|
|
btrfs_set_header_nritems(right, nritems);
|
|
data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
|
|
|
|
copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
|
|
btrfs_item_nr_offset(mid),
|
|
nritems * sizeof(struct btrfs_item));
|
|
|
|
copy_extent_buffer(right, l,
|
|
btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
|
|
data_copy_size, btrfs_leaf_data(l) +
|
|
leaf_data_end(root, l), data_copy_size);
|
|
|
|
rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
|
|
btrfs_item_end_nr(l, mid);
|
|
|
|
for (i = 0; i < nritems; i++) {
|
|
struct btrfs_item *item = btrfs_item_nr(i);
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(right, item, &token);
|
|
btrfs_set_token_item_offset(right, item,
|
|
ioff + rt_data_off, &token);
|
|
}
|
|
|
|
btrfs_set_header_nritems(l, mid);
|
|
btrfs_item_key(right, &disk_key, 0);
|
|
insert_ptr(trans, root, path, &disk_key, right->start,
|
|
path->slots[1] + 1, 1);
|
|
|
|
btrfs_mark_buffer_dirty(right);
|
|
btrfs_mark_buffer_dirty(l);
|
|
BUG_ON(path->slots[0] != slot);
|
|
|
|
if (mid <= slot) {
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[0] -= mid;
|
|
path->slots[1] += 1;
|
|
} else {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
|
|
BUG_ON(path->slots[0] < 0);
|
|
}
|
|
|
|
/*
|
|
* double splits happen when we need to insert a big item in the middle
|
|
* of a leaf. A double split can leave us with 3 mostly empty leaves:
|
|
* leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
|
|
* A B C
|
|
*
|
|
* We avoid this by trying to push the items on either side of our target
|
|
* into the adjacent leaves. If all goes well we can avoid the double split
|
|
* completely.
|
|
*/
|
|
static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int data_size)
|
|
{
|
|
int ret;
|
|
int progress = 0;
|
|
int slot;
|
|
u32 nritems;
|
|
int space_needed = data_size;
|
|
|
|
slot = path->slots[0];
|
|
if (slot < btrfs_header_nritems(path->nodes[0]))
|
|
space_needed -= btrfs_leaf_free_space(root, path->nodes[0]);
|
|
|
|
/*
|
|
* try to push all the items after our slot into the
|
|
* right leaf
|
|
*/
|
|
ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (ret == 0)
|
|
progress++;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]);
|
|
/*
|
|
* our goal is to get our slot at the start or end of a leaf. If
|
|
* we've done so we're done
|
|
*/
|
|
if (path->slots[0] == 0 || path->slots[0] == nritems)
|
|
return 0;
|
|
|
|
if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
|
|
return 0;
|
|
|
|
/* try to push all the items before our slot into the next leaf */
|
|
slot = path->slots[0];
|
|
ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (ret == 0)
|
|
progress++;
|
|
|
|
if (progress)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* split the path's leaf in two, making sure there is at least data_size
|
|
* available for the resulting leaf level of the path.
|
|
*
|
|
* returns 0 if all went well and < 0 on failure.
|
|
*/
|
|
static noinline int split_leaf(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_key *ins_key,
|
|
struct btrfs_path *path, int data_size,
|
|
int extend)
|
|
{
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *l;
|
|
u32 nritems;
|
|
int mid;
|
|
int slot;
|
|
struct extent_buffer *right;
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
int ret = 0;
|
|
int wret;
|
|
int split;
|
|
int num_doubles = 0;
|
|
int tried_avoid_double = 0;
|
|
|
|
l = path->nodes[0];
|
|
slot = path->slots[0];
|
|
if (extend && data_size + btrfs_item_size_nr(l, slot) +
|
|
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
|
|
return -EOVERFLOW;
|
|
|
|
/* first try to make some room by pushing left and right */
|
|
if (data_size && path->nodes[1]) {
|
|
int space_needed = data_size;
|
|
|
|
if (slot < btrfs_header_nritems(l))
|
|
space_needed -= btrfs_leaf_free_space(root, l);
|
|
|
|
wret = push_leaf_right(trans, root, path, space_needed,
|
|
space_needed, 0, 0);
|
|
if (wret < 0)
|
|
return wret;
|
|
if (wret) {
|
|
wret = push_leaf_left(trans, root, path, space_needed,
|
|
space_needed, 0, (u32)-1);
|
|
if (wret < 0)
|
|
return wret;
|
|
}
|
|
l = path->nodes[0];
|
|
|
|
/* did the pushes work? */
|
|
if (btrfs_leaf_free_space(root, l) >= data_size)
|
|
return 0;
|
|
}
|
|
|
|
if (!path->nodes[1]) {
|
|
ret = insert_new_root(trans, root, path, 1);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
again:
|
|
split = 1;
|
|
l = path->nodes[0];
|
|
slot = path->slots[0];
|
|
nritems = btrfs_header_nritems(l);
|
|
mid = (nritems + 1) / 2;
|
|
|
|
if (mid <= slot) {
|
|
if (nritems == 1 ||
|
|
leaf_space_used(l, mid, nritems - mid) + data_size >
|
|
BTRFS_LEAF_DATA_SIZE(root)) {
|
|
if (slot >= nritems) {
|
|
split = 0;
|
|
} else {
|
|
mid = slot;
|
|
if (mid != nritems &&
|
|
leaf_space_used(l, mid, nritems - mid) +
|
|
data_size > BTRFS_LEAF_DATA_SIZE(root)) {
|
|
if (data_size && !tried_avoid_double)
|
|
goto push_for_double;
|
|
split = 2;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
if (leaf_space_used(l, 0, mid) + data_size >
|
|
BTRFS_LEAF_DATA_SIZE(root)) {
|
|
if (!extend && data_size && slot == 0) {
|
|
split = 0;
|
|
} else if ((extend || !data_size) && slot == 0) {
|
|
mid = 1;
|
|
} else {
|
|
mid = slot;
|
|
if (mid != nritems &&
|
|
leaf_space_used(l, mid, nritems - mid) +
|
|
data_size > BTRFS_LEAF_DATA_SIZE(root)) {
|
|
if (data_size && !tried_avoid_double)
|
|
goto push_for_double;
|
|
split = 2;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (split == 0)
|
|
btrfs_cpu_key_to_disk(&disk_key, ins_key);
|
|
else
|
|
btrfs_item_key(l, &disk_key, mid);
|
|
|
|
right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
|
|
&disk_key, 0, l->start, 0);
|
|
if (IS_ERR(right))
|
|
return PTR_ERR(right);
|
|
|
|
root_add_used(root, root->nodesize);
|
|
|
|
memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
|
|
btrfs_set_header_bytenr(right, right->start);
|
|
btrfs_set_header_generation(right, trans->transid);
|
|
btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
|
|
btrfs_set_header_owner(right, root->root_key.objectid);
|
|
btrfs_set_header_level(right, 0);
|
|
write_extent_buffer(right, fs_info->fsid,
|
|
btrfs_header_fsid(), BTRFS_FSID_SIZE);
|
|
|
|
write_extent_buffer(right, fs_info->chunk_tree_uuid,
|
|
btrfs_header_chunk_tree_uuid(right),
|
|
BTRFS_UUID_SIZE);
|
|
|
|
if (split == 0) {
|
|
if (mid <= slot) {
|
|
btrfs_set_header_nritems(right, 0);
|
|
insert_ptr(trans, root, path, &disk_key, right->start,
|
|
path->slots[1] + 1, 1);
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[0] = 0;
|
|
path->slots[1] += 1;
|
|
} else {
|
|
btrfs_set_header_nritems(right, 0);
|
|
insert_ptr(trans, root, path, &disk_key, right->start,
|
|
path->slots[1], 1);
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[0] = 0;
|
|
if (path->slots[1] == 0)
|
|
fixup_low_keys(fs_info, path, &disk_key, 1);
|
|
}
|
|
btrfs_mark_buffer_dirty(right);
|
|
return ret;
|
|
}
|
|
|
|
copy_for_split(trans, root, path, l, right, slot, mid, nritems);
|
|
|
|
if (split == 2) {
|
|
BUG_ON(num_doubles != 0);
|
|
num_doubles++;
|
|
goto again;
|
|
}
|
|
|
|
return 0;
|
|
|
|
push_for_double:
|
|
push_for_double_split(trans, root, path, data_size);
|
|
tried_avoid_double = 1;
|
|
if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
|
|
return 0;
|
|
goto again;
|
|
}
|
|
|
|
static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int ins_len)
|
|
{
|
|
struct btrfs_key key;
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_file_extent_item *fi;
|
|
u64 extent_len = 0;
|
|
u32 item_size;
|
|
int ret;
|
|
|
|
leaf = path->nodes[0];
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
|
|
key.type != BTRFS_EXTENT_CSUM_KEY);
|
|
|
|
if (btrfs_leaf_free_space(root, leaf) >= ins_len)
|
|
return 0;
|
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
if (key.type == BTRFS_EXTENT_DATA_KEY) {
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
struct btrfs_file_extent_item);
|
|
extent_len = btrfs_file_extent_num_bytes(leaf, fi);
|
|
}
|
|
btrfs_release_path(path);
|
|
|
|
path->keep_locks = 1;
|
|
path->search_for_split = 1;
|
|
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
|
|
path->search_for_split = 0;
|
|
if (ret > 0)
|
|
ret = -EAGAIN;
|
|
if (ret < 0)
|
|
goto err;
|
|
|
|
ret = -EAGAIN;
|
|
leaf = path->nodes[0];
|
|
/* if our item isn't there, return now */
|
|
if (item_size != btrfs_item_size_nr(leaf, path->slots[0]))
|
|
goto err;
|
|
|
|
/* the leaf has changed, it now has room. return now */
|
|
if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len)
|
|
goto err;
|
|
|
|
if (key.type == BTRFS_EXTENT_DATA_KEY) {
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
struct btrfs_file_extent_item);
|
|
if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
|
|
goto err;
|
|
}
|
|
|
|
btrfs_set_path_blocking(path);
|
|
ret = split_leaf(trans, root, &key, path, ins_len, 1);
|
|
if (ret)
|
|
goto err;
|
|
|
|
path->keep_locks = 0;
|
|
btrfs_unlock_up_safe(path, 1);
|
|
return 0;
|
|
err:
|
|
path->keep_locks = 0;
|
|
return ret;
|
|
}
|
|
|
|
static noinline int split_item(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *new_key,
|
|
unsigned long split_offset)
|
|
{
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_item *item;
|
|
struct btrfs_item *new_item;
|
|
int slot;
|
|
char *buf;
|
|
u32 nritems;
|
|
u32 item_size;
|
|
u32 orig_offset;
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
leaf = path->nodes[0];
|
|
BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
|
|
|
|
btrfs_set_path_blocking(path);
|
|
|
|
item = btrfs_item_nr(path->slots[0]);
|
|
orig_offset = btrfs_item_offset(leaf, item);
|
|
item_size = btrfs_item_size(leaf, item);
|
|
|
|
buf = kmalloc(item_size, GFP_NOFS);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
|
|
path->slots[0]), item_size);
|
|
|
|
slot = path->slots[0] + 1;
|
|
nritems = btrfs_header_nritems(leaf);
|
|
if (slot != nritems) {
|
|
/* shift the items */
|
|
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
|
|
btrfs_item_nr_offset(slot),
|
|
(nritems - slot) * sizeof(struct btrfs_item));
|
|
}
|
|
|
|
btrfs_cpu_key_to_disk(&disk_key, new_key);
|
|
btrfs_set_item_key(leaf, &disk_key, slot);
|
|
|
|
new_item = btrfs_item_nr(slot);
|
|
|
|
btrfs_set_item_offset(leaf, new_item, orig_offset);
|
|
btrfs_set_item_size(leaf, new_item, item_size - split_offset);
|
|
|
|
btrfs_set_item_offset(leaf, item,
|
|
orig_offset + item_size - split_offset);
|
|
btrfs_set_item_size(leaf, item, split_offset);
|
|
|
|
btrfs_set_header_nritems(leaf, nritems + 1);
|
|
|
|
/* write the data for the start of the original item */
|
|
write_extent_buffer(leaf, buf,
|
|
btrfs_item_ptr_offset(leaf, path->slots[0]),
|
|
split_offset);
|
|
|
|
/* write the data for the new item */
|
|
write_extent_buffer(leaf, buf + split_offset,
|
|
btrfs_item_ptr_offset(leaf, slot),
|
|
item_size - split_offset);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
|
|
kfree(buf);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function splits a single item into two items,
|
|
* giving 'new_key' to the new item and splitting the
|
|
* old one at split_offset (from the start of the item).
|
|
*
|
|
* The path may be released by this operation. After
|
|
* the split, the path is pointing to the old item. The
|
|
* new item is going to be in the same node as the old one.
|
|
*
|
|
* Note, the item being split must be smaller enough to live alone on
|
|
* a tree block with room for one extra struct btrfs_item
|
|
*
|
|
* This allows us to split the item in place, keeping a lock on the
|
|
* leaf the entire time.
|
|
*/
|
|
int btrfs_split_item(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *new_key,
|
|
unsigned long split_offset)
|
|
{
|
|
int ret;
|
|
ret = setup_leaf_for_split(trans, root, path,
|
|
sizeof(struct btrfs_item));
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = split_item(trans, root, path, new_key, split_offset);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This function duplicate a item, giving 'new_key' to the new item.
|
|
* It guarantees both items live in the same tree leaf and the new item
|
|
* is contiguous with the original item.
|
|
*
|
|
* This allows us to split file extent in place, keeping a lock on the
|
|
* leaf the entire time.
|
|
*/
|
|
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *new_key)
|
|
{
|
|
struct extent_buffer *leaf;
|
|
int ret;
|
|
u32 item_size;
|
|
|
|
leaf = path->nodes[0];
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
|
|
ret = setup_leaf_for_split(trans, root, path,
|
|
item_size + sizeof(struct btrfs_item));
|
|
if (ret)
|
|
return ret;
|
|
|
|
path->slots[0]++;
|
|
setup_items_for_insert(root, path, new_key, &item_size,
|
|
item_size, item_size +
|
|
sizeof(struct btrfs_item), 1);
|
|
leaf = path->nodes[0];
|
|
memcpy_extent_buffer(leaf,
|
|
btrfs_item_ptr_offset(leaf, path->slots[0]),
|
|
btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
|
|
item_size);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* make the item pointed to by the path smaller. new_size indicates
|
|
* how small to make it, and from_end tells us if we just chop bytes
|
|
* off the end of the item or if we shift the item to chop bytes off
|
|
* the front.
|
|
*/
|
|
void btrfs_truncate_item(struct btrfs_root *root, struct btrfs_path *path,
|
|
u32 new_size, int from_end)
|
|
{
|
|
int slot;
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_item *item;
|
|
u32 nritems;
|
|
unsigned int data_end;
|
|
unsigned int old_data_start;
|
|
unsigned int old_size;
|
|
unsigned int size_diff;
|
|
int i;
|
|
struct btrfs_map_token token;
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
|
|
old_size = btrfs_item_size_nr(leaf, slot);
|
|
if (old_size == new_size)
|
|
return;
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
data_end = leaf_data_end(root, leaf);
|
|
|
|
old_data_start = btrfs_item_offset_nr(leaf, slot);
|
|
|
|
size_diff = old_size - new_size;
|
|
|
|
BUG_ON(slot < 0);
|
|
BUG_ON(slot >= nritems);
|
|
|
|
/*
|
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size
|
|
*/
|
|
/* first correct the data pointers */
|
|
for (i = slot; i < nritems; i++) {
|
|
u32 ioff;
|
|
item = btrfs_item_nr(i);
|
|
|
|
ioff = btrfs_token_item_offset(leaf, item, &token);
|
|
btrfs_set_token_item_offset(leaf, item,
|
|
ioff + size_diff, &token);
|
|
}
|
|
|
|
/* shift the data */
|
|
if (from_end) {
|
|
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
|
|
data_end + size_diff, btrfs_leaf_data(leaf) +
|
|
data_end, old_data_start + new_size - data_end);
|
|
} else {
|
|
struct btrfs_disk_key disk_key;
|
|
u64 offset;
|
|
|
|
btrfs_item_key(leaf, &disk_key, slot);
|
|
|
|
if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
|
|
unsigned long ptr;
|
|
struct btrfs_file_extent_item *fi;
|
|
|
|
fi = btrfs_item_ptr(leaf, slot,
|
|
struct btrfs_file_extent_item);
|
|
fi = (struct btrfs_file_extent_item *)(
|
|
(unsigned long)fi - size_diff);
|
|
|
|
if (btrfs_file_extent_type(leaf, fi) ==
|
|
BTRFS_FILE_EXTENT_INLINE) {
|
|
ptr = btrfs_item_ptr_offset(leaf, slot);
|
|
memmove_extent_buffer(leaf, ptr,
|
|
(unsigned long)fi,
|
|
BTRFS_FILE_EXTENT_INLINE_DATA_START);
|
|
}
|
|
}
|
|
|
|
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
|
|
data_end + size_diff, btrfs_leaf_data(leaf) +
|
|
data_end, old_data_start - data_end);
|
|
|
|
offset = btrfs_disk_key_offset(&disk_key);
|
|
btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
|
|
btrfs_set_item_key(leaf, &disk_key, slot);
|
|
if (slot == 0)
|
|
fixup_low_keys(root->fs_info, path, &disk_key, 1);
|
|
}
|
|
|
|
item = btrfs_item_nr(slot);
|
|
btrfs_set_item_size(leaf, item, new_size);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
if (btrfs_leaf_free_space(root, leaf) < 0) {
|
|
btrfs_print_leaf(root, leaf);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* make the item pointed to by the path bigger, data_size is the added size.
|
|
*/
|
|
void btrfs_extend_item(struct btrfs_root *root, struct btrfs_path *path,
|
|
u32 data_size)
|
|
{
|
|
int slot;
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_item *item;
|
|
u32 nritems;
|
|
unsigned int data_end;
|
|
unsigned int old_data;
|
|
unsigned int old_size;
|
|
int i;
|
|
struct btrfs_map_token token;
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
data_end = leaf_data_end(root, leaf);
|
|
|
|
if (btrfs_leaf_free_space(root, leaf) < data_size) {
|
|
btrfs_print_leaf(root, leaf);
|
|
BUG();
|
|
}
|
|
slot = path->slots[0];
|
|
old_data = btrfs_item_end_nr(leaf, slot);
|
|
|
|
BUG_ON(slot < 0);
|
|
if (slot >= nritems) {
|
|
btrfs_print_leaf(root, leaf);
|
|
btrfs_crit(root->fs_info, "slot %d too large, nritems %d",
|
|
slot, nritems);
|
|
BUG_ON(1);
|
|
}
|
|
|
|
/*
|
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size
|
|
*/
|
|
/* first correct the data pointers */
|
|
for (i = slot; i < nritems; i++) {
|
|
u32 ioff;
|
|
item = btrfs_item_nr(i);
|
|
|
|
ioff = btrfs_token_item_offset(leaf, item, &token);
|
|
btrfs_set_token_item_offset(leaf, item,
|
|
ioff - data_size, &token);
|
|
}
|
|
|
|
/* shift the data */
|
|
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
|
|
data_end - data_size, btrfs_leaf_data(leaf) +
|
|
data_end, old_data - data_end);
|
|
|
|
data_end = old_data;
|
|
old_size = btrfs_item_size_nr(leaf, slot);
|
|
item = btrfs_item_nr(slot);
|
|
btrfs_set_item_size(leaf, item, old_size + data_size);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
if (btrfs_leaf_free_space(root, leaf) < 0) {
|
|
btrfs_print_leaf(root, leaf);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* this is a helper for btrfs_insert_empty_items, the main goal here is
|
|
* to save stack depth by doing the bulk of the work in a function
|
|
* that doesn't call btrfs_search_slot
|
|
*/
|
|
void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
|
|
struct btrfs_key *cpu_key, u32 *data_size,
|
|
u32 total_data, u32 total_size, int nr)
|
|
{
|
|
struct btrfs_item *item;
|
|
int i;
|
|
u32 nritems;
|
|
unsigned int data_end;
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *leaf;
|
|
int slot;
|
|
struct btrfs_map_token token;
|
|
|
|
if (path->slots[0] == 0) {
|
|
btrfs_cpu_key_to_disk(&disk_key, cpu_key);
|
|
fixup_low_keys(root->fs_info, path, &disk_key, 1);
|
|
}
|
|
btrfs_unlock_up_safe(path, 1);
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
data_end = leaf_data_end(root, leaf);
|
|
|
|
if (btrfs_leaf_free_space(root, leaf) < total_size) {
|
|
btrfs_print_leaf(root, leaf);
|
|
btrfs_crit(root->fs_info, "not enough freespace need %u have %d",
|
|
total_size, btrfs_leaf_free_space(root, leaf));
|
|
BUG();
|
|
}
|
|
|
|
if (slot != nritems) {
|
|
unsigned int old_data = btrfs_item_end_nr(leaf, slot);
|
|
|
|
if (old_data < data_end) {
|
|
btrfs_print_leaf(root, leaf);
|
|
btrfs_crit(root->fs_info, "slot %d old_data %d data_end %d",
|
|
slot, old_data, data_end);
|
|
BUG_ON(1);
|
|
}
|
|
/*
|
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size
|
|
*/
|
|
/* first correct the data pointers */
|
|
for (i = slot; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
item = btrfs_item_nr( i);
|
|
ioff = btrfs_token_item_offset(leaf, item, &token);
|
|
btrfs_set_token_item_offset(leaf, item,
|
|
ioff - total_data, &token);
|
|
}
|
|
/* shift the items */
|
|
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
|
|
btrfs_item_nr_offset(slot),
|
|
(nritems - slot) * sizeof(struct btrfs_item));
|
|
|
|
/* shift the data */
|
|
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
|
|
data_end - total_data, btrfs_leaf_data(leaf) +
|
|
data_end, old_data - data_end);
|
|
data_end = old_data;
|
|
}
|
|
|
|
/* setup the item for the new data */
|
|
for (i = 0; i < nr; i++) {
|
|
btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
|
|
btrfs_set_item_key(leaf, &disk_key, slot + i);
|
|
item = btrfs_item_nr(slot + i);
|
|
btrfs_set_token_item_offset(leaf, item,
|
|
data_end - data_size[i], &token);
|
|
data_end -= data_size[i];
|
|
btrfs_set_token_item_size(leaf, item, data_size[i], &token);
|
|
}
|
|
|
|
btrfs_set_header_nritems(leaf, nritems + nr);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
if (btrfs_leaf_free_space(root, leaf) < 0) {
|
|
btrfs_print_leaf(root, leaf);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Given a key and some data, insert items into the tree.
|
|
* This does all the path init required, making room in the tree if needed.
|
|
*/
|
|
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct btrfs_key *cpu_key, u32 *data_size,
|
|
int nr)
|
|
{
|
|
int ret = 0;
|
|
int slot;
|
|
int i;
|
|
u32 total_size = 0;
|
|
u32 total_data = 0;
|
|
|
|
for (i = 0; i < nr; i++)
|
|
total_data += data_size[i];
|
|
|
|
total_size = total_data + (nr * sizeof(struct btrfs_item));
|
|
ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
|
|
if (ret == 0)
|
|
return -EEXIST;
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
slot = path->slots[0];
|
|
BUG_ON(slot < 0);
|
|
|
|
setup_items_for_insert(root, path, cpu_key, data_size,
|
|
total_data, total_size, nr);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Given a key and some data, insert an item into the tree.
|
|
* This does all the path init required, making room in the tree if needed.
|
|
*/
|
|
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_key *cpu_key, void *data, u32
|
|
data_size)
|
|
{
|
|
int ret = 0;
|
|
struct btrfs_path *path;
|
|
struct extent_buffer *leaf;
|
|
unsigned long ptr;
|
|
|
|
path = btrfs_alloc_path();
|
|
if (!path)
|
|
return -ENOMEM;
|
|
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
|
|
if (!ret) {
|
|
leaf = path->nodes[0];
|
|
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
|
|
write_extent_buffer(leaf, data, ptr, data_size);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
}
|
|
btrfs_free_path(path);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* delete the pointer from a given node.
|
|
*
|
|
* the tree should have been previously balanced so the deletion does not
|
|
* empty a node.
|
|
*/
|
|
static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
|
|
int level, int slot)
|
|
{
|
|
struct extent_buffer *parent = path->nodes[level];
|
|
u32 nritems;
|
|
int ret;
|
|
|
|
nritems = btrfs_header_nritems(parent);
|
|
if (slot != nritems - 1) {
|
|
if (level)
|
|
tree_mod_log_eb_move(root->fs_info, parent, slot,
|
|
slot + 1, nritems - slot - 1);
|
|
memmove_extent_buffer(parent,
|
|
btrfs_node_key_ptr_offset(slot),
|
|
btrfs_node_key_ptr_offset(slot + 1),
|
|
sizeof(struct btrfs_key_ptr) *
|
|
(nritems - slot - 1));
|
|
} else if (level) {
|
|
ret = tree_mod_log_insert_key(root->fs_info, parent, slot,
|
|
MOD_LOG_KEY_REMOVE, GFP_NOFS);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
|
|
nritems--;
|
|
btrfs_set_header_nritems(parent, nritems);
|
|
if (nritems == 0 && parent == root->node) {
|
|
BUG_ON(btrfs_header_level(root->node) != 1);
|
|
/* just turn the root into a leaf and break */
|
|
btrfs_set_header_level(root->node, 0);
|
|
} else if (slot == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_node_key(parent, &disk_key, 0);
|
|
fixup_low_keys(root->fs_info, path, &disk_key, level + 1);
|
|
}
|
|
btrfs_mark_buffer_dirty(parent);
|
|
}
|
|
|
|
/*
|
|
* a helper function to delete the leaf pointed to by path->slots[1] and
|
|
* path->nodes[1].
|
|
*
|
|
* This deletes the pointer in path->nodes[1] and frees the leaf
|
|
* block extent. zero is returned if it all worked out, < 0 otherwise.
|
|
*
|
|
* The path must have already been setup for deleting the leaf, including
|
|
* all the proper balancing. path->nodes[1] must be locked.
|
|
*/
|
|
static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct extent_buffer *leaf)
|
|
{
|
|
WARN_ON(btrfs_header_generation(leaf) != trans->transid);
|
|
del_ptr(root, path, 1, path->slots[1]);
|
|
|
|
/*
|
|
* btrfs_free_extent is expensive, we want to make sure we
|
|
* aren't holding any locks when we call it
|
|
*/
|
|
btrfs_unlock_up_safe(path, 0);
|
|
|
|
root_sub_used(root, leaf->len);
|
|
|
|
extent_buffer_get(leaf);
|
|
btrfs_free_tree_block(trans, root, leaf, 0, 1);
|
|
free_extent_buffer_stale(leaf);
|
|
}
|
|
/*
|
|
* delete the item at the leaf level in path. If that empties
|
|
* the leaf, remove it from the tree
|
|
*/
|
|
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
struct btrfs_path *path, int slot, int nr)
|
|
{
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_item *item;
|
|
int last_off;
|
|
int dsize = 0;
|
|
int ret = 0;
|
|
int wret;
|
|
int i;
|
|
u32 nritems;
|
|
struct btrfs_map_token token;
|
|
|
|
btrfs_init_map_token(&token);
|
|
|
|
leaf = path->nodes[0];
|
|
last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
|
|
|
|
for (i = 0; i < nr; i++)
|
|
dsize += btrfs_item_size_nr(leaf, slot + i);
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
if (slot + nr != nritems) {
|
|
int data_end = leaf_data_end(root, leaf);
|
|
|
|
memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
|
|
data_end + dsize,
|
|
btrfs_leaf_data(leaf) + data_end,
|
|
last_off - data_end);
|
|
|
|
for (i = slot + nr; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
item = btrfs_item_nr(i);
|
|
ioff = btrfs_token_item_offset(leaf, item, &token);
|
|
btrfs_set_token_item_offset(leaf, item,
|
|
ioff + dsize, &token);
|
|
}
|
|
|
|
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
|
|
btrfs_item_nr_offset(slot + nr),
|
|
sizeof(struct btrfs_item) *
|
|
(nritems - slot - nr));
|
|
}
|
|
btrfs_set_header_nritems(leaf, nritems - nr);
|
|
nritems -= nr;
|
|
|
|
/* delete the leaf if we've emptied it */
|
|
if (nritems == 0) {
|
|
if (leaf == root->node) {
|
|
btrfs_set_header_level(leaf, 0);
|
|
} else {
|
|
btrfs_set_path_blocking(path);
|
|
clean_tree_block(trans, root->fs_info, leaf);
|
|
btrfs_del_leaf(trans, root, path, leaf);
|
|
}
|
|
} else {
|
|
int used = leaf_space_used(leaf, 0, nritems);
|
|
if (slot == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_item_key(leaf, &disk_key, 0);
|
|
fixup_low_keys(root->fs_info, path, &disk_key, 1);
|
|
}
|
|
|
|
/* delete the leaf if it is mostly empty */
|
|
if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
|
|
/* push_leaf_left fixes the path.
|
|
* make sure the path still points to our leaf
|
|
* for possible call to del_ptr below
|
|
*/
|
|
slot = path->slots[1];
|
|
extent_buffer_get(leaf);
|
|
|
|
btrfs_set_path_blocking(path);
|
|
wret = push_leaf_left(trans, root, path, 1, 1,
|
|
1, (u32)-1);
|
|
if (wret < 0 && wret != -ENOSPC)
|
|
ret = wret;
|
|
|
|
if (path->nodes[0] == leaf &&
|
|
btrfs_header_nritems(leaf)) {
|
|
wret = push_leaf_right(trans, root, path, 1,
|
|
1, 1, 0);
|
|
if (wret < 0 && wret != -ENOSPC)
|
|
ret = wret;
|
|
}
|
|
|
|
if (btrfs_header_nritems(leaf) == 0) {
|
|
path->slots[1] = slot;
|
|
btrfs_del_leaf(trans, root, path, leaf);
|
|
free_extent_buffer(leaf);
|
|
ret = 0;
|
|
} else {
|
|
/* if we're still in the path, make sure
|
|
* we're dirty. Otherwise, one of the
|
|
* push_leaf functions must have already
|
|
* dirtied this buffer
|
|
*/
|
|
if (path->nodes[0] == leaf)
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
free_extent_buffer(leaf);
|
|
}
|
|
} else {
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* search the tree again to find a leaf with lesser keys
|
|
* returns 0 if it found something or 1 if there are no lesser leaves.
|
|
* returns < 0 on io errors.
|
|
*
|
|
* This may release the path, and so you may lose any locks held at the
|
|
* time you call it.
|
|
*/
|
|
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
|
|
{
|
|
struct btrfs_key key;
|
|
struct btrfs_disk_key found_key;
|
|
int ret;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
|
|
|
|
if (key.offset > 0) {
|
|
key.offset--;
|
|
} else if (key.type > 0) {
|
|
key.type--;
|
|
key.offset = (u64)-1;
|
|
} else if (key.objectid > 0) {
|
|
key.objectid--;
|
|
key.type = (u8)-1;
|
|
key.offset = (u64)-1;
|
|
} else {
|
|
return 1;
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
btrfs_item_key(path->nodes[0], &found_key, 0);
|
|
ret = comp_keys(&found_key, &key);
|
|
/*
|
|
* We might have had an item with the previous key in the tree right
|
|
* before we released our path. And after we released our path, that
|
|
* item might have been pushed to the first slot (0) of the leaf we
|
|
* were holding due to a tree balance. Alternatively, an item with the
|
|
* previous key can exist as the only element of a leaf (big fat item).
|
|
* Therefore account for these 2 cases, so that our callers (like
|
|
* btrfs_previous_item) don't miss an existing item with a key matching
|
|
* the previous key we computed above.
|
|
*/
|
|
if (ret <= 0)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* A helper function to walk down the tree starting at min_key, and looking
|
|
* for nodes or leaves that are have a minimum transaction id.
|
|
* This is used by the btree defrag code, and tree logging
|
|
*
|
|
* This does not cow, but it does stuff the starting key it finds back
|
|
* into min_key, so you can call btrfs_search_slot with cow=1 on the
|
|
* key and get a writable path.
|
|
*
|
|
* This does lock as it descends, and path->keep_locks should be set
|
|
* to 1 by the caller.
|
|
*
|
|
* This honors path->lowest_level to prevent descent past a given level
|
|
* of the tree.
|
|
*
|
|
* min_trans indicates the oldest transaction that you are interested
|
|
* in walking through. Any nodes or leaves older than min_trans are
|
|
* skipped over (without reading them).
|
|
*
|
|
* returns zero if something useful was found, < 0 on error and 1 if there
|
|
* was nothing in the tree that matched the search criteria.
|
|
*/
|
|
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
|
|
struct btrfs_path *path,
|
|
u64 min_trans)
|
|
{
|
|
struct extent_buffer *cur;
|
|
struct btrfs_key found_key;
|
|
int slot;
|
|
int sret;
|
|
u32 nritems;
|
|
int level;
|
|
int ret = 1;
|
|
int keep_locks = path->keep_locks;
|
|
|
|
path->keep_locks = 1;
|
|
again:
|
|
cur = btrfs_read_lock_root_node(root);
|
|
level = btrfs_header_level(cur);
|
|
WARN_ON(path->nodes[level]);
|
|
path->nodes[level] = cur;
|
|
path->locks[level] = BTRFS_READ_LOCK;
|
|
|
|
if (btrfs_header_generation(cur) < min_trans) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
while (1) {
|
|
nritems = btrfs_header_nritems(cur);
|
|
level = btrfs_header_level(cur);
|
|
sret = bin_search(cur, min_key, level, &slot);
|
|
|
|
/* at the lowest level, we're done, setup the path and exit */
|
|
if (level == path->lowest_level) {
|
|
if (slot >= nritems)
|
|
goto find_next_key;
|
|
ret = 0;
|
|
path->slots[level] = slot;
|
|
btrfs_item_key_to_cpu(cur, &found_key, slot);
|
|
goto out;
|
|
}
|
|
if (sret && slot > 0)
|
|
slot--;
|
|
/*
|
|
* check this node pointer against the min_trans parameters.
|
|
* If it is too old, old, skip to the next one.
|
|
*/
|
|
while (slot < nritems) {
|
|
u64 gen;
|
|
|
|
gen = btrfs_node_ptr_generation(cur, slot);
|
|
if (gen < min_trans) {
|
|
slot++;
|
|
continue;
|
|
}
|
|
break;
|
|
}
|
|
find_next_key:
|
|
/*
|
|
* we didn't find a candidate key in this node, walk forward
|
|
* and find another one
|
|
*/
|
|
if (slot >= nritems) {
|
|
path->slots[level] = slot;
|
|
btrfs_set_path_blocking(path);
|
|
sret = btrfs_find_next_key(root, path, min_key, level,
|
|
min_trans);
|
|
if (sret == 0) {
|
|
btrfs_release_path(path);
|
|
goto again;
|
|
} else {
|
|
goto out;
|
|
}
|
|
}
|
|
/* save our key for returning back */
|
|
btrfs_node_key_to_cpu(cur, &found_key, slot);
|
|
path->slots[level] = slot;
|
|
if (level == path->lowest_level) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
btrfs_set_path_blocking(path);
|
|
cur = read_node_slot(root, cur, slot);
|
|
BUG_ON(!cur); /* -ENOMEM */
|
|
|
|
btrfs_tree_read_lock(cur);
|
|
|
|
path->locks[level - 1] = BTRFS_READ_LOCK;
|
|
path->nodes[level - 1] = cur;
|
|
unlock_up(path, level, 1, 0, NULL);
|
|
btrfs_clear_path_blocking(path, NULL, 0);
|
|
}
|
|
out:
|
|
path->keep_locks = keep_locks;
|
|
if (ret == 0) {
|
|
btrfs_unlock_up_safe(path, path->lowest_level + 1);
|
|
btrfs_set_path_blocking(path);
|
|
memcpy(min_key, &found_key, sizeof(found_key));
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void tree_move_down(struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int *level, int root_level)
|
|
{
|
|
BUG_ON(*level == 0);
|
|
path->nodes[*level - 1] = read_node_slot(root, path->nodes[*level],
|
|
path->slots[*level]);
|
|
path->slots[*level - 1] = 0;
|
|
(*level)--;
|
|
}
|
|
|
|
static int tree_move_next_or_upnext(struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int *level, int root_level)
|
|
{
|
|
int ret = 0;
|
|
int nritems;
|
|
nritems = btrfs_header_nritems(path->nodes[*level]);
|
|
|
|
path->slots[*level]++;
|
|
|
|
while (path->slots[*level] >= nritems) {
|
|
if (*level == root_level)
|
|
return -1;
|
|
|
|
/* move upnext */
|
|
path->slots[*level] = 0;
|
|
free_extent_buffer(path->nodes[*level]);
|
|
path->nodes[*level] = NULL;
|
|
(*level)++;
|
|
path->slots[*level]++;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[*level]);
|
|
ret = 1;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Returns 1 if it had to move up and next. 0 is returned if it moved only next
|
|
* or down.
|
|
*/
|
|
static int tree_advance(struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int *level, int root_level,
|
|
int allow_down,
|
|
struct btrfs_key *key)
|
|
{
|
|
int ret;
|
|
|
|
if (*level == 0 || !allow_down) {
|
|
ret = tree_move_next_or_upnext(root, path, level, root_level);
|
|
} else {
|
|
tree_move_down(root, path, level, root_level);
|
|
ret = 0;
|
|
}
|
|
if (ret >= 0) {
|
|
if (*level == 0)
|
|
btrfs_item_key_to_cpu(path->nodes[*level], key,
|
|
path->slots[*level]);
|
|
else
|
|
btrfs_node_key_to_cpu(path->nodes[*level], key,
|
|
path->slots[*level]);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int tree_compare_item(struct btrfs_root *left_root,
|
|
struct btrfs_path *left_path,
|
|
struct btrfs_path *right_path,
|
|
char *tmp_buf)
|
|
{
|
|
int cmp;
|
|
int len1, len2;
|
|
unsigned long off1, off2;
|
|
|
|
len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
|
|
len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
|
|
if (len1 != len2)
|
|
return 1;
|
|
|
|
off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
|
|
off2 = btrfs_item_ptr_offset(right_path->nodes[0],
|
|
right_path->slots[0]);
|
|
|
|
read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
|
|
|
|
cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
|
|
if (cmp)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
#define ADVANCE 1
|
|
#define ADVANCE_ONLY_NEXT -1
|
|
|
|
/*
|
|
* This function compares two trees and calls the provided callback for
|
|
* every changed/new/deleted item it finds.
|
|
* If shared tree blocks are encountered, whole subtrees are skipped, making
|
|
* the compare pretty fast on snapshotted subvolumes.
|
|
*
|
|
* This currently works on commit roots only. As commit roots are read only,
|
|
* we don't do any locking. The commit roots are protected with transactions.
|
|
* Transactions are ended and rejoined when a commit is tried in between.
|
|
*
|
|
* This function checks for modifications done to the trees while comparing.
|
|
* If it detects a change, it aborts immediately.
|
|
*/
|
|
int btrfs_compare_trees(struct btrfs_root *left_root,
|
|
struct btrfs_root *right_root,
|
|
btrfs_changed_cb_t changed_cb, void *ctx)
|
|
{
|
|
int ret;
|
|
int cmp;
|
|
struct btrfs_path *left_path = NULL;
|
|
struct btrfs_path *right_path = NULL;
|
|
struct btrfs_key left_key;
|
|
struct btrfs_key right_key;
|
|
char *tmp_buf = NULL;
|
|
int left_root_level;
|
|
int right_root_level;
|
|
int left_level;
|
|
int right_level;
|
|
int left_end_reached;
|
|
int right_end_reached;
|
|
int advance_left;
|
|
int advance_right;
|
|
u64 left_blockptr;
|
|
u64 right_blockptr;
|
|
u64 left_gen;
|
|
u64 right_gen;
|
|
|
|
left_path = btrfs_alloc_path();
|
|
if (!left_path) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
right_path = btrfs_alloc_path();
|
|
if (!right_path) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
tmp_buf = kmalloc(left_root->nodesize, GFP_NOFS);
|
|
if (!tmp_buf) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
left_path->search_commit_root = 1;
|
|
left_path->skip_locking = 1;
|
|
right_path->search_commit_root = 1;
|
|
right_path->skip_locking = 1;
|
|
|
|
/*
|
|
* Strategy: Go to the first items of both trees. Then do
|
|
*
|
|
* If both trees are at level 0
|
|
* Compare keys of current items
|
|
* If left < right treat left item as new, advance left tree
|
|
* and repeat
|
|
* If left > right treat right item as deleted, advance right tree
|
|
* and repeat
|
|
* If left == right do deep compare of items, treat as changed if
|
|
* needed, advance both trees and repeat
|
|
* If both trees are at the same level but not at level 0
|
|
* Compare keys of current nodes/leafs
|
|
* If left < right advance left tree and repeat
|
|
* If left > right advance right tree and repeat
|
|
* If left == right compare blockptrs of the next nodes/leafs
|
|
* If they match advance both trees but stay at the same level
|
|
* and repeat
|
|
* If they don't match advance both trees while allowing to go
|
|
* deeper and repeat
|
|
* If tree levels are different
|
|
* Advance the tree that needs it and repeat
|
|
*
|
|
* Advancing a tree means:
|
|
* If we are at level 0, try to go to the next slot. If that's not
|
|
* possible, go one level up and repeat. Stop when we found a level
|
|
* where we could go to the next slot. We may at this point be on a
|
|
* node or a leaf.
|
|
*
|
|
* If we are not at level 0 and not on shared tree blocks, go one
|
|
* level deeper.
|
|
*
|
|
* If we are not at level 0 and on shared tree blocks, go one slot to
|
|
* the right if possible or go up and right.
|
|
*/
|
|
|
|
down_read(&left_root->fs_info->commit_root_sem);
|
|
left_level = btrfs_header_level(left_root->commit_root);
|
|
left_root_level = left_level;
|
|
left_path->nodes[left_level] = left_root->commit_root;
|
|
extent_buffer_get(left_path->nodes[left_level]);
|
|
|
|
right_level = btrfs_header_level(right_root->commit_root);
|
|
right_root_level = right_level;
|
|
right_path->nodes[right_level] = right_root->commit_root;
|
|
extent_buffer_get(right_path->nodes[right_level]);
|
|
up_read(&left_root->fs_info->commit_root_sem);
|
|
|
|
if (left_level == 0)
|
|
btrfs_item_key_to_cpu(left_path->nodes[left_level],
|
|
&left_key, left_path->slots[left_level]);
|
|
else
|
|
btrfs_node_key_to_cpu(left_path->nodes[left_level],
|
|
&left_key, left_path->slots[left_level]);
|
|
if (right_level == 0)
|
|
btrfs_item_key_to_cpu(right_path->nodes[right_level],
|
|
&right_key, right_path->slots[right_level]);
|
|
else
|
|
btrfs_node_key_to_cpu(right_path->nodes[right_level],
|
|
&right_key, right_path->slots[right_level]);
|
|
|
|
left_end_reached = right_end_reached = 0;
|
|
advance_left = advance_right = 0;
|
|
|
|
while (1) {
|
|
if (advance_left && !left_end_reached) {
|
|
ret = tree_advance(left_root, left_path, &left_level,
|
|
left_root_level,
|
|
advance_left != ADVANCE_ONLY_NEXT,
|
|
&left_key);
|
|
if (ret < 0)
|
|
left_end_reached = ADVANCE;
|
|
advance_left = 0;
|
|
}
|
|
if (advance_right && !right_end_reached) {
|
|
ret = tree_advance(right_root, right_path, &right_level,
|
|
right_root_level,
|
|
advance_right != ADVANCE_ONLY_NEXT,
|
|
&right_key);
|
|
if (ret < 0)
|
|
right_end_reached = ADVANCE;
|
|
advance_right = 0;
|
|
}
|
|
|
|
if (left_end_reached && right_end_reached) {
|
|
ret = 0;
|
|
goto out;
|
|
} else if (left_end_reached) {
|
|
if (right_level == 0) {
|
|
ret = changed_cb(left_root, right_root,
|
|
left_path, right_path,
|
|
&right_key,
|
|
BTRFS_COMPARE_TREE_DELETED,
|
|
ctx);
|
|
if (ret < 0)
|
|
goto out;
|
|
}
|
|
advance_right = ADVANCE;
|
|
continue;
|
|
} else if (right_end_reached) {
|
|
if (left_level == 0) {
|
|
ret = changed_cb(left_root, right_root,
|
|
left_path, right_path,
|
|
&left_key,
|
|
BTRFS_COMPARE_TREE_NEW,
|
|
ctx);
|
|
if (ret < 0)
|
|
goto out;
|
|
}
|
|
advance_left = ADVANCE;
|
|
continue;
|
|
}
|
|
|
|
if (left_level == 0 && right_level == 0) {
|
|
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
|
|
if (cmp < 0) {
|
|
ret = changed_cb(left_root, right_root,
|
|
left_path, right_path,
|
|
&left_key,
|
|
BTRFS_COMPARE_TREE_NEW,
|
|
ctx);
|
|
if (ret < 0)
|
|
goto out;
|
|
advance_left = ADVANCE;
|
|
} else if (cmp > 0) {
|
|
ret = changed_cb(left_root, right_root,
|
|
left_path, right_path,
|
|
&right_key,
|
|
BTRFS_COMPARE_TREE_DELETED,
|
|
ctx);
|
|
if (ret < 0)
|
|
goto out;
|
|
advance_right = ADVANCE;
|
|
} else {
|
|
enum btrfs_compare_tree_result result;
|
|
|
|
WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
|
|
ret = tree_compare_item(left_root, left_path,
|
|
right_path, tmp_buf);
|
|
if (ret)
|
|
result = BTRFS_COMPARE_TREE_CHANGED;
|
|
else
|
|
result = BTRFS_COMPARE_TREE_SAME;
|
|
ret = changed_cb(left_root, right_root,
|
|
left_path, right_path,
|
|
&left_key, result, ctx);
|
|
if (ret < 0)
|
|
goto out;
|
|
advance_left = ADVANCE;
|
|
advance_right = ADVANCE;
|
|
}
|
|
} else if (left_level == right_level) {
|
|
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
|
|
if (cmp < 0) {
|
|
advance_left = ADVANCE;
|
|
} else if (cmp > 0) {
|
|
advance_right = ADVANCE;
|
|
} else {
|
|
left_blockptr = btrfs_node_blockptr(
|
|
left_path->nodes[left_level],
|
|
left_path->slots[left_level]);
|
|
right_blockptr = btrfs_node_blockptr(
|
|
right_path->nodes[right_level],
|
|
right_path->slots[right_level]);
|
|
left_gen = btrfs_node_ptr_generation(
|
|
left_path->nodes[left_level],
|
|
left_path->slots[left_level]);
|
|
right_gen = btrfs_node_ptr_generation(
|
|
right_path->nodes[right_level],
|
|
right_path->slots[right_level]);
|
|
if (left_blockptr == right_blockptr &&
|
|
left_gen == right_gen) {
|
|
/*
|
|
* As we're on a shared block, don't
|
|
* allow to go deeper.
|
|
*/
|
|
advance_left = ADVANCE_ONLY_NEXT;
|
|
advance_right = ADVANCE_ONLY_NEXT;
|
|
} else {
|
|
advance_left = ADVANCE;
|
|
advance_right = ADVANCE;
|
|
}
|
|
}
|
|
} else if (left_level < right_level) {
|
|
advance_right = ADVANCE;
|
|
} else {
|
|
advance_left = ADVANCE;
|
|
}
|
|
}
|
|
|
|
out:
|
|
btrfs_free_path(left_path);
|
|
btrfs_free_path(right_path);
|
|
kfree(tmp_buf);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this is similar to btrfs_next_leaf, but does not try to preserve
|
|
* and fixup the path. It looks for and returns the next key in the
|
|
* tree based on the current path and the min_trans parameters.
|
|
*
|
|
* 0 is returned if another key is found, < 0 if there are any errors
|
|
* and 1 is returned if there are no higher keys in the tree
|
|
*
|
|
* path->keep_locks should be set to 1 on the search made before
|
|
* calling this function.
|
|
*/
|
|
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
|
|
struct btrfs_key *key, int level, u64 min_trans)
|
|
{
|
|
int slot;
|
|
struct extent_buffer *c;
|
|
|
|
WARN_ON(!path->keep_locks);
|
|
while (level < BTRFS_MAX_LEVEL) {
|
|
if (!path->nodes[level])
|
|
return 1;
|
|
|
|
slot = path->slots[level] + 1;
|
|
c = path->nodes[level];
|
|
next:
|
|
if (slot >= btrfs_header_nritems(c)) {
|
|
int ret;
|
|
int orig_lowest;
|
|
struct btrfs_key cur_key;
|
|
if (level + 1 >= BTRFS_MAX_LEVEL ||
|
|
!path->nodes[level + 1])
|
|
return 1;
|
|
|
|
if (path->locks[level + 1]) {
|
|
level++;
|
|
continue;
|
|
}
|
|
|
|
slot = btrfs_header_nritems(c) - 1;
|
|
if (level == 0)
|
|
btrfs_item_key_to_cpu(c, &cur_key, slot);
|
|
else
|
|
btrfs_node_key_to_cpu(c, &cur_key, slot);
|
|
|
|
orig_lowest = path->lowest_level;
|
|
btrfs_release_path(path);
|
|
path->lowest_level = level;
|
|
ret = btrfs_search_slot(NULL, root, &cur_key, path,
|
|
0, 0);
|
|
path->lowest_level = orig_lowest;
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
c = path->nodes[level];
|
|
slot = path->slots[level];
|
|
if (ret == 0)
|
|
slot++;
|
|
goto next;
|
|
}
|
|
|
|
if (level == 0)
|
|
btrfs_item_key_to_cpu(c, key, slot);
|
|
else {
|
|
u64 gen = btrfs_node_ptr_generation(c, slot);
|
|
|
|
if (gen < min_trans) {
|
|
slot++;
|
|
goto next;
|
|
}
|
|
btrfs_node_key_to_cpu(c, key, slot);
|
|
}
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* search the tree again to find a leaf with greater keys
|
|
* returns 0 if it found something or 1 if there are no greater leaves.
|
|
* returns < 0 on io errors.
|
|
*/
|
|
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
|
|
{
|
|
return btrfs_next_old_leaf(root, path, 0);
|
|
}
|
|
|
|
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
|
|
u64 time_seq)
|
|
{
|
|
int slot;
|
|
int level;
|
|
struct extent_buffer *c;
|
|
struct extent_buffer *next;
|
|
struct btrfs_key key;
|
|
u32 nritems;
|
|
int ret;
|
|
int old_spinning = path->leave_spinning;
|
|
int next_rw_lock = 0;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]);
|
|
if (nritems == 0)
|
|
return 1;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
|
|
again:
|
|
level = 1;
|
|
next = NULL;
|
|
next_rw_lock = 0;
|
|
btrfs_release_path(path);
|
|
|
|
path->keep_locks = 1;
|
|
path->leave_spinning = 1;
|
|
|
|
if (time_seq)
|
|
ret = btrfs_search_old_slot(root, &key, path, time_seq);
|
|
else
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
path->keep_locks = 0;
|
|
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]);
|
|
/*
|
|
* by releasing the path above we dropped all our locks. A balance
|
|
* could have added more items next to the key that used to be
|
|
* at the very end of the block. So, check again here and
|
|
* advance the path if there are now more items available.
|
|
*/
|
|
if (nritems > 0 && path->slots[0] < nritems - 1) {
|
|
if (ret == 0)
|
|
path->slots[0]++;
|
|
ret = 0;
|
|
goto done;
|
|
}
|
|
/*
|
|
* So the above check misses one case:
|
|
* - after releasing the path above, someone has removed the item that
|
|
* used to be at the very end of the block, and balance between leafs
|
|
* gets another one with bigger key.offset to replace it.
|
|
*
|
|
* This one should be returned as well, or we can get leaf corruption
|
|
* later(esp. in __btrfs_drop_extents()).
|
|
*
|
|
* And a bit more explanation about this check,
|
|
* with ret > 0, the key isn't found, the path points to the slot
|
|
* where it should be inserted, so the path->slots[0] item must be the
|
|
* bigger one.
|
|
*/
|
|
if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) {
|
|
ret = 0;
|
|
goto done;
|
|
}
|
|
|
|
while (level < BTRFS_MAX_LEVEL) {
|
|
if (!path->nodes[level]) {
|
|
ret = 1;
|
|
goto done;
|
|
}
|
|
|
|
slot = path->slots[level] + 1;
|
|
c = path->nodes[level];
|
|
if (slot >= btrfs_header_nritems(c)) {
|
|
level++;
|
|
if (level == BTRFS_MAX_LEVEL) {
|
|
ret = 1;
|
|
goto done;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (next) {
|
|
btrfs_tree_unlock_rw(next, next_rw_lock);
|
|
free_extent_buffer(next);
|
|
}
|
|
|
|
next = c;
|
|
next_rw_lock = path->locks[level];
|
|
ret = read_block_for_search(NULL, root, path, &next, level,
|
|
slot, &key, 0);
|
|
if (ret == -EAGAIN)
|
|
goto again;
|
|
|
|
if (ret < 0) {
|
|
btrfs_release_path(path);
|
|
goto done;
|
|
}
|
|
|
|
if (!path->skip_locking) {
|
|
ret = btrfs_try_tree_read_lock(next);
|
|
if (!ret && time_seq) {
|
|
/*
|
|
* If we don't get the lock, we may be racing
|
|
* with push_leaf_left, holding that lock while
|
|
* itself waiting for the leaf we've currently
|
|
* locked. To solve this situation, we give up
|
|
* on our lock and cycle.
|
|
*/
|
|
free_extent_buffer(next);
|
|
btrfs_release_path(path);
|
|
cond_resched();
|
|
goto again;
|
|
}
|
|
if (!ret) {
|
|
btrfs_set_path_blocking(path);
|
|
btrfs_tree_read_lock(next);
|
|
btrfs_clear_path_blocking(path, next,
|
|
BTRFS_READ_LOCK);
|
|
}
|
|
next_rw_lock = BTRFS_READ_LOCK;
|
|
}
|
|
break;
|
|
}
|
|
path->slots[level] = slot;
|
|
while (1) {
|
|
level--;
|
|
c = path->nodes[level];
|
|
if (path->locks[level])
|
|
btrfs_tree_unlock_rw(c, path->locks[level]);
|
|
|
|
free_extent_buffer(c);
|
|
path->nodes[level] = next;
|
|
path->slots[level] = 0;
|
|
if (!path->skip_locking)
|
|
path->locks[level] = next_rw_lock;
|
|
if (!level)
|
|
break;
|
|
|
|
ret = read_block_for_search(NULL, root, path, &next, level,
|
|
0, &key, 0);
|
|
if (ret == -EAGAIN)
|
|
goto again;
|
|
|
|
if (ret < 0) {
|
|
btrfs_release_path(path);
|
|
goto done;
|
|
}
|
|
|
|
if (!path->skip_locking) {
|
|
ret = btrfs_try_tree_read_lock(next);
|
|
if (!ret) {
|
|
btrfs_set_path_blocking(path);
|
|
btrfs_tree_read_lock(next);
|
|
btrfs_clear_path_blocking(path, next,
|
|
BTRFS_READ_LOCK);
|
|
}
|
|
next_rw_lock = BTRFS_READ_LOCK;
|
|
}
|
|
}
|
|
ret = 0;
|
|
done:
|
|
unlock_up(path, 0, 1, 0, NULL);
|
|
path->leave_spinning = old_spinning;
|
|
if (!old_spinning)
|
|
btrfs_set_path_blocking(path);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
|
|
* searching until it gets past min_objectid or finds an item of 'type'
|
|
*
|
|
* returns 0 if something is found, 1 if nothing was found and < 0 on error
|
|
*/
|
|
int btrfs_previous_item(struct btrfs_root *root,
|
|
struct btrfs_path *path, u64 min_objectid,
|
|
int type)
|
|
{
|
|
struct btrfs_key found_key;
|
|
struct extent_buffer *leaf;
|
|
u32 nritems;
|
|
int ret;
|
|
|
|
while (1) {
|
|
if (path->slots[0] == 0) {
|
|
btrfs_set_path_blocking(path);
|
|
ret = btrfs_prev_leaf(root, path);
|
|
if (ret != 0)
|
|
return ret;
|
|
} else {
|
|
path->slots[0]--;
|
|
}
|
|
leaf = path->nodes[0];
|
|
nritems = btrfs_header_nritems(leaf);
|
|
if (nritems == 0)
|
|
return 1;
|
|
if (path->slots[0] == nritems)
|
|
path->slots[0]--;
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
|
if (found_key.objectid < min_objectid)
|
|
break;
|
|
if (found_key.type == type)
|
|
return 0;
|
|
if (found_key.objectid == min_objectid &&
|
|
found_key.type < type)
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* search in extent tree to find a previous Metadata/Data extent item with
|
|
* min objecitd.
|
|
*
|
|
* returns 0 if something is found, 1 if nothing was found and < 0 on error
|
|
*/
|
|
int btrfs_previous_extent_item(struct btrfs_root *root,
|
|
struct btrfs_path *path, u64 min_objectid)
|
|
{
|
|
struct btrfs_key found_key;
|
|
struct extent_buffer *leaf;
|
|
u32 nritems;
|
|
int ret;
|
|
|
|
while (1) {
|
|
if (path->slots[0] == 0) {
|
|
btrfs_set_path_blocking(path);
|
|
ret = btrfs_prev_leaf(root, path);
|
|
if (ret != 0)
|
|
return ret;
|
|
} else {
|
|
path->slots[0]--;
|
|
}
|
|
leaf = path->nodes[0];
|
|
nritems = btrfs_header_nritems(leaf);
|
|
if (nritems == 0)
|
|
return 1;
|
|
if (path->slots[0] == nritems)
|
|
path->slots[0]--;
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
|
if (found_key.objectid < min_objectid)
|
|
break;
|
|
if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
|
|
found_key.type == BTRFS_METADATA_ITEM_KEY)
|
|
return 0;
|
|
if (found_key.objectid == min_objectid &&
|
|
found_key.type < BTRFS_EXTENT_ITEM_KEY)
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|