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linux/fs/btrfs/transaction.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include <linux/uuid.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "locking.h"
#include "tree-log.h"
#include "inode-map.h"
#include "volumes.h"
#include "dev-replace.h"
#include "qgroup.h"
#define BTRFS_ROOT_TRANS_TAG 0
static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
[TRANS_STATE_RUNNING] = 0U,
[TRANS_STATE_BLOCKED] = __TRANS_START,
[TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
[TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN),
[TRANS_STATE_UNBLOCKED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
__TRANS_JOIN_NOLOCK),
[TRANS_STATE_COMPLETED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
__TRANS_JOIN_NOLOCK),
};
void btrfs_put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(refcount_read(&transaction->use_count) == 0);
if (refcount_dec_and_test(&transaction->use_count)) {
BUG_ON(!list_empty(&transaction->list));
WARN_ON(!RB_EMPTY_ROOT(
&transaction->delayed_refs.href_root.rb_root));
if (transaction->delayed_refs.pending_csums)
btrfs_err(transaction->fs_info,
"pending csums is %llu",
transaction->delayed_refs.pending_csums);
/*
* If any block groups are found in ->deleted_bgs then it's
* because the transaction was aborted and a commit did not
* happen (things failed before writing the new superblock
* and calling btrfs_finish_extent_commit()), so we can not
* discard the physical locations of the block groups.
*/
while (!list_empty(&transaction->deleted_bgs)) {
struct btrfs_block_group_cache *cache;
cache = list_first_entry(&transaction->deleted_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&cache->bg_list);
btrfs_put_block_group_trimming(cache);
btrfs_put_block_group(cache);
}
WARN_ON(!list_empty(&transaction->dev_update_list));
kfree(transaction);
}
}
static noinline void switch_commit_roots(struct btrfs_transaction *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root, *tmp;
down_write(&fs_info->commit_root_sem);
list_for_each_entry_safe(root, tmp, &trans->switch_commits,
dirty_list) {
list_del_init(&root->dirty_list);
free_extent_buffer(root->commit_root);
root->commit_root = btrfs_root_node(root);
if (is_fstree(root->root_key.objectid))
btrfs_unpin_free_ino(root);
extent_io_tree_release(&root->dirty_log_pages);
btrfs_qgroup_clean_swapped_blocks(root);
}
/* We can free old roots now. */
spin_lock(&trans->dropped_roots_lock);
while (!list_empty(&trans->dropped_roots)) {
root = list_first_entry(&trans->dropped_roots,
struct btrfs_root, root_list);
list_del_init(&root->root_list);
spin_unlock(&trans->dropped_roots_lock);
btrfs_drop_and_free_fs_root(fs_info, root);
spin_lock(&trans->dropped_roots_lock);
}
spin_unlock(&trans->dropped_roots_lock);
up_write(&fs_info->commit_root_sem);
}
static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
unsigned int type)
{
if (type & TRANS_EXTWRITERS)
atomic_inc(&trans->num_extwriters);
}
static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
unsigned int type)
{
if (type & TRANS_EXTWRITERS)
atomic_dec(&trans->num_extwriters);
}
static inline void extwriter_counter_init(struct btrfs_transaction *trans,
unsigned int type)
{
atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
}
static inline int extwriter_counter_read(struct btrfs_transaction *trans)
{
return atomic_read(&trans->num_extwriters);
}
/*
* either allocate a new transaction or hop into the existing one
*/
static noinline int join_transaction(struct btrfs_fs_info *fs_info,
unsigned int type)
{
struct btrfs_transaction *cur_trans;
spin_lock(&fs_info->trans_lock);
loop:
/* The file system has been taken offline. No new transactions. */
if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
spin_unlock(&fs_info->trans_lock);
return -EROFS;
}
cur_trans = fs_info->running_transaction;
if (cur_trans) {
if (cur_trans->aborted) {
spin_unlock(&fs_info->trans_lock);
return cur_trans->aborted;
}
if (btrfs_blocked_trans_types[cur_trans->state] & type) {
spin_unlock(&fs_info->trans_lock);
return -EBUSY;
}
refcount_inc(&cur_trans->use_count);
atomic_inc(&cur_trans->num_writers);
extwriter_counter_inc(cur_trans, type);
spin_unlock(&fs_info->trans_lock);
return 0;
}
spin_unlock(&fs_info->trans_lock);
/*
* If we are ATTACH, we just want to catch the current transaction,
* and commit it. If there is no transaction, just return ENOENT.
*/
if (type == TRANS_ATTACH)
return -ENOENT;
/*
* JOIN_NOLOCK only happens during the transaction commit, so
* it is impossible that ->running_transaction is NULL
*/
BUG_ON(type == TRANS_JOIN_NOLOCK);
cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
if (!cur_trans)
return -ENOMEM;
spin_lock(&fs_info->trans_lock);
if (fs_info->running_transaction) {
/*
* someone started a transaction after we unlocked. Make sure
* to redo the checks above
*/
kfree(cur_trans);
goto loop;
} else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
spin_unlock(&fs_info->trans_lock);
kfree(cur_trans);
return -EROFS;
}
cur_trans->fs_info = fs_info;
atomic_set(&cur_trans->num_writers, 1);
extwriter_counter_init(cur_trans, type);
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->state = TRANS_STATE_RUNNING;
/*
* One for this trans handle, one so it will live on until we
* commit the transaction.
*/
refcount_set(&cur_trans->use_count, 2);
cur_trans->flags = 0;
cur_trans->start_time = ktime_get_seconds();
memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
atomic_set(&cur_trans->delayed_refs.num_entries, 0);
/*
* although the tree mod log is per file system and not per transaction,
* the log must never go across transaction boundaries.
*/
smp_mb();
if (!list_empty(&fs_info->tree_mod_seq_list))
WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
atomic64_set(&fs_info->tree_mod_seq, 0);
spin_lock_init(&cur_trans->delayed_refs.lock);
INIT_LIST_HEAD(&cur_trans->pending_snapshots);
INIT_LIST_HEAD(&cur_trans->dev_update_list);
INIT_LIST_HEAD(&cur_trans->switch_commits);
INIT_LIST_HEAD(&cur_trans->dirty_bgs);
INIT_LIST_HEAD(&cur_trans->io_bgs);
INIT_LIST_HEAD(&cur_trans->dropped_roots);
mutex_init(&cur_trans->cache_write_mutex);
spin_lock_init(&cur_trans->dirty_bgs_lock);
INIT_LIST_HEAD(&cur_trans->deleted_bgs);
spin_lock_init(&cur_trans->dropped_roots_lock);
list_add_tail(&cur_trans->list, &fs_info->trans_list);
extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
fs_info->generation++;
cur_trans->transid = fs_info->generation;
fs_info->running_transaction = cur_trans;
cur_trans->aborted = 0;
spin_unlock(&fs_info->trans_lock);
return 0;
}
/*
* this does all the record keeping required to make sure that a reference
* counted root is properly recorded in a given transaction. This is required
* to make sure the old root from before we joined the transaction is deleted
* when the transaction commits
*/
static int record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
int force)
{
struct btrfs_fs_info *fs_info = root->fs_info;
if ((test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
root->last_trans < trans->transid) || force) {
WARN_ON(root == fs_info->extent_root);
WARN_ON(!force && root->commit_root != root->node);
/*
* see below for IN_TRANS_SETUP usage rules
* we have the reloc mutex held now, so there
* is only one writer in this function
*/
set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
/* make sure readers find IN_TRANS_SETUP before
* they find our root->last_trans update
*/
smp_wmb();
spin_lock(&fs_info->fs_roots_radix_lock);
if (root->last_trans == trans->transid && !force) {
spin_unlock(&fs_info->fs_roots_radix_lock);
return 0;
}
radix_tree_tag_set(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&fs_info->fs_roots_radix_lock);
root->last_trans = trans->transid;
/* this is pretty tricky. We don't want to
* take the relocation lock in btrfs_record_root_in_trans
* unless we're really doing the first setup for this root in
* this transaction.
*
* Normally we'd use root->last_trans as a flag to decide
* if we want to take the expensive mutex.
*
* But, we have to set root->last_trans before we
* init the relocation root, otherwise, we trip over warnings
* in ctree.c. The solution used here is to flag ourselves
* with root IN_TRANS_SETUP. When this is 1, we're still
* fixing up the reloc trees and everyone must wait.
*
* When this is zero, they can trust root->last_trans and fly
* through btrfs_record_root_in_trans without having to take the
* lock. smp_wmb() makes sure that all the writes above are
* done before we pop in the zero below
*/
btrfs_init_reloc_root(trans, root);
smp_mb__before_atomic();
clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
}
return 0;
}
void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
/* Add ourselves to the transaction dropped list */
spin_lock(&cur_trans->dropped_roots_lock);
list_add_tail(&root->root_list, &cur_trans->dropped_roots);
spin_unlock(&cur_trans->dropped_roots_lock);
/* Make sure we don't try to update the root at commit time */
spin_lock(&fs_info->fs_roots_radix_lock);
radix_tree_tag_clear(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&fs_info->fs_roots_radix_lock);
}
int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
return 0;
/*
* see record_root_in_trans for comments about IN_TRANS_SETUP usage
* and barriers
*/
smp_rmb();
if (root->last_trans == trans->transid &&
!test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
return 0;
mutex_lock(&fs_info->reloc_mutex);
record_root_in_trans(trans, root, 0);
mutex_unlock(&fs_info->reloc_mutex);
return 0;
}
static inline int is_transaction_blocked(struct btrfs_transaction *trans)
{
return (trans->state >= TRANS_STATE_BLOCKED &&
trans->state < TRANS_STATE_UNBLOCKED &&
!trans->aborted);
}
/* wait for commit against the current transaction to become unblocked
* when this is done, it is safe to start a new transaction, but the current
* transaction might not be fully on disk.
*/
static void wait_current_trans(struct btrfs_fs_info *fs_info)
{
struct btrfs_transaction *cur_trans;
spin_lock(&fs_info->trans_lock);
cur_trans = fs_info->running_transaction;
if (cur_trans && is_transaction_blocked(cur_trans)) {
refcount_inc(&cur_trans->use_count);
spin_unlock(&fs_info->trans_lock);
wait_event(fs_info->transaction_wait,
cur_trans->state >= TRANS_STATE_UNBLOCKED ||
cur_trans->aborted);
btrfs_put_transaction(cur_trans);
} else {
spin_unlock(&fs_info->trans_lock);
}
}
static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
{
if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
return 0;
if (type == TRANS_START)
return 1;
return 0;
}
static inline bool need_reserve_reloc_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
if (!fs_info->reloc_ctl ||
!test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
root->reloc_root)
return false;
return true;
}
static struct btrfs_trans_handle *
start_transaction(struct btrfs_root *root, unsigned int num_items,
unsigned int type, enum btrfs_reserve_flush_enum flush,
bool enforce_qgroups)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
struct btrfs_trans_handle *h;
struct btrfs_transaction *cur_trans;
u64 num_bytes = 0;
u64 qgroup_reserved = 0;
bool reloc_reserved = false;
int ret;
/* Send isn't supposed to start transactions. */
ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
return ERR_PTR(-EROFS);
if (current->journal_info) {
WARN_ON(type & TRANS_EXTWRITERS);
h = current->journal_info;
refcount_inc(&h->use_count);
WARN_ON(refcount_read(&h->use_count) > 2);
h->orig_rsv = h->block_rsv;
h->block_rsv = NULL;
goto got_it;
}
/*
* Do the reservation before we join the transaction so we can do all
* the appropriate flushing if need be.
*/
if (num_items && root != fs_info->chunk_root) {
struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
u64 delayed_refs_bytes = 0;
qgroup_reserved = num_items * fs_info->nodesize;
ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
enforce_qgroups);
if (ret)
return ERR_PTR(ret);
/*
* We want to reserve all the bytes we may need all at once, so
* we only do 1 enospc flushing cycle per transaction start. We
* accomplish this by simply assuming we'll do 2 x num_items
* worth of delayed refs updates in this trans handle, and
* refill that amount for whatever is missing in the reserve.
*/
num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
if (delayed_refs_rsv->full == 0) {
delayed_refs_bytes = num_bytes;
num_bytes <<= 1;
}
/*
* Do the reservation for the relocation root creation
*/
if (need_reserve_reloc_root(root)) {
num_bytes += fs_info->nodesize;
reloc_reserved = true;
}
ret = btrfs_block_rsv_add(root, rsv, num_bytes, flush);
if (ret)
goto reserve_fail;
if (delayed_refs_bytes) {
btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
delayed_refs_bytes);
num_bytes -= delayed_refs_bytes;
}
} else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
!delayed_refs_rsv->full) {
/*
* Some people call with btrfs_start_transaction(root, 0)
* because they can be throttled, but have some other mechanism
* for reserving space. We still want these guys to refill the
* delayed block_rsv so just add 1 items worth of reservation
* here.
*/
ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
if (ret)
goto reserve_fail;
}
again:
h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
if (!h) {
ret = -ENOMEM;
goto alloc_fail;
}
/*
* If we are JOIN_NOLOCK we're already committing a transaction and
* waiting on this guy, so we don't need to do the sb_start_intwrite
* because we're already holding a ref. We need this because we could
* have raced in and did an fsync() on a file which can kick a commit
* and then we deadlock with somebody doing a freeze.
*
* If we are ATTACH, it means we just want to catch the current
* transaction and commit it, so we needn't do sb_start_intwrite().
*/
if (type & __TRANS_FREEZABLE)
sb_start_intwrite(fs_info->sb);
if (may_wait_transaction(fs_info, type))
wait_current_trans(fs_info);
do {
ret = join_transaction(fs_info, type);
if (ret == -EBUSY) {
wait_current_trans(fs_info);
if (unlikely(type == TRANS_ATTACH))
ret = -ENOENT;
}
} while (ret == -EBUSY);
if (ret < 0)
goto join_fail;
cur_trans = fs_info->running_transaction;
h->transid = cur_trans->transid;
h->transaction = cur_trans;
h->root = root;
refcount_set(&h->use_count, 1);
h->fs_info = root->fs_info;
h->type = type;
h->can_flush_pending_bgs = true;
INIT_LIST_HEAD(&h->new_bgs);
smp_mb();
if (cur_trans->state >= TRANS_STATE_BLOCKED &&
may_wait_transaction(fs_info, type)) {
current->journal_info = h;
btrfs_commit_transaction(h);
goto again;
}
if (num_bytes) {
trace_btrfs_space_reservation(fs_info, "transaction",
h->transid, num_bytes, 1);
h->block_rsv = &fs_info->trans_block_rsv;
h->bytes_reserved = num_bytes;
h->reloc_reserved = reloc_reserved;
}
got_it:
btrfs_record_root_in_trans(h, root);
if (!current->journal_info)
current->journal_info = h;
return h;
join_fail:
if (type & __TRANS_FREEZABLE)
sb_end_intwrite(fs_info->sb);
kmem_cache_free(btrfs_trans_handle_cachep, h);
alloc_fail:
if (num_bytes)
btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
num_bytes);
reserve_fail:
btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
return ERR_PTR(ret);
}
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
unsigned int num_items)
{
return start_transaction(root, num_items, TRANS_START,
BTRFS_RESERVE_FLUSH_ALL, true);
}
struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
struct btrfs_root *root,
unsigned int num_items,
int min_factor)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_trans_handle *trans;
u64 num_bytes;
int ret;
/*
* We have two callers: unlink and block group removal. The
* former should succeed even if we will temporarily exceed
* quota and the latter operates on the extent root so
* qgroup enforcement is ignored anyway.
*/
trans = start_transaction(root, num_items, TRANS_START,
BTRFS_RESERVE_FLUSH_ALL, false);
if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
return trans;
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return trans;
num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv,
num_bytes, min_factor);
if (ret) {
btrfs_end_transaction(trans);
return ERR_PTR(ret);
}
trans->block_rsv = &fs_info->trans_block_rsv;
trans->bytes_reserved = num_bytes;
trace_btrfs_space_reservation(fs_info, "transaction",
trans->transid, num_bytes, 1);
return trans;
}
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
true);
}
struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
BTRFS_RESERVE_NO_FLUSH, true);
}
/*
* btrfs_attach_transaction() - catch the running transaction
*
* It is used when we want to commit the current the transaction, but
* don't want to start a new one.
*
* Note: If this function return -ENOENT, it just means there is no
* running transaction. But it is possible that the inactive transaction
* is still in the memory, not fully on disk. If you hope there is no
* inactive transaction in the fs when -ENOENT is returned, you should
* invoke
* btrfs_attach_transaction_barrier()
*/
struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_ATTACH,
BTRFS_RESERVE_NO_FLUSH, true);
}
/*
* btrfs_attach_transaction_barrier() - catch the running transaction
*
* It is similar to the above function, the difference is this one
* will wait for all the inactive transactions until they fully
* complete.
*/
struct btrfs_trans_handle *
btrfs_attach_transaction_barrier(struct btrfs_root *root)
{
struct btrfs_trans_handle *trans;
trans = start_transaction(root, 0, TRANS_ATTACH,
BTRFS_RESERVE_NO_FLUSH, true);
if (trans == ERR_PTR(-ENOENT))
btrfs_wait_for_commit(root->fs_info, 0);
return trans;
}
/* wait for a transaction commit to be fully complete */
static noinline void wait_for_commit(struct btrfs_transaction *commit)
{
wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
}
int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
{
struct btrfs_transaction *cur_trans = NULL, *t;
int ret = 0;
if (transid) {
if (transid <= fs_info->last_trans_committed)
goto out;
/* find specified transaction */
spin_lock(&fs_info->trans_lock);
list_for_each_entry(t, &fs_info->trans_list, list) {
if (t->transid == transid) {
cur_trans = t;
refcount_inc(&cur_trans->use_count);
ret = 0;
break;
}
if (t->transid > transid) {
ret = 0;
break;
}
}
spin_unlock(&fs_info->trans_lock);
/*
* The specified transaction doesn't exist, or we
* raced with btrfs_commit_transaction
*/
if (!cur_trans) {
if (transid > fs_info->last_trans_committed)
ret = -EINVAL;
goto out;
}
} else {
/* find newest transaction that is committing | committed */
spin_lock(&fs_info->trans_lock);
list_for_each_entry_reverse(t, &fs_info->trans_list,
list) {
if (t->state >= TRANS_STATE_COMMIT_START) {
if (t->state == TRANS_STATE_COMPLETED)
break;
cur_trans = t;
refcount_inc(&cur_trans->use_count);
break;
}
}
spin_unlock(&fs_info->trans_lock);
if (!cur_trans)
goto out; /* nothing committing|committed */
}
wait_for_commit(cur_trans);
btrfs_put_transaction(cur_trans);
out:
return ret;
}
void btrfs_throttle(struct btrfs_fs_info *fs_info)
{
wait_current_trans(fs_info);
}
static int should_end_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
if (btrfs_check_space_for_delayed_refs(fs_info))
return 1;
return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
}
int btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_transaction *cur_trans = trans->transaction;
smp_mb();
if (cur_trans->state >= TRANS_STATE_BLOCKED ||
cur_trans->delayed_refs.flushing)
return 1;
return should_end_transaction(trans);
}
static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
if (!trans->block_rsv) {
ASSERT(!trans->bytes_reserved);
return;
}
if (!trans->bytes_reserved)
return;
ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
trace_btrfs_space_reservation(fs_info, "transaction",
trans->transid, trans->bytes_reserved, 0);
btrfs_block_rsv_release(fs_info, trans->block_rsv,
trans->bytes_reserved);
trans->bytes_reserved = 0;
}
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
int throttle)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
int lock = (trans->type != TRANS_JOIN_NOLOCK);
int err = 0;
if (refcount_read(&trans->use_count) > 1) {
refcount_dec(&trans->use_count);
trans->block_rsv = trans->orig_rsv;
return 0;
}
btrfs_trans_release_metadata(trans);
trans->block_rsv = NULL;
btrfs_create_pending_block_groups(trans);
btrfs_trans_release_chunk_metadata(trans);
if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
if (throttle)
return btrfs_commit_transaction(trans);
else
wake_up_process(info->transaction_kthread);
}
if (trans->type & __TRANS_FREEZABLE)
sb_end_intwrite(info->sb);
WARN_ON(cur_trans != info->running_transaction);
WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
atomic_dec(&cur_trans->num_writers);
extwriter_counter_dec(cur_trans, trans->type);
cond_wake_up(&cur_trans->writer_wait);
btrfs_put_transaction(cur_trans);
if (current->journal_info == trans)
current->journal_info = NULL;
if (throttle)
btrfs_run_delayed_iputs(info);
if (trans->aborted ||
test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
wake_up_process(info->transaction_kthread);
err = -EIO;
}
kmem_cache_free(btrfs_trans_handle_cachep, trans);
return err;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans)
{
return __btrfs_end_transaction(trans, 0);
}
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
{
return __btrfs_end_transaction(trans, 1);
}
/*
* when btree blocks are allocated, they have some corresponding bits set for
* them in one of two extent_io trees. This is used to make sure all of
* those extents are sent to disk but does not wait on them
*/
int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
struct extent_io_tree *dirty_pages, int mark)
{
int err = 0;
int werr = 0;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
struct extent_state *cached_state = NULL;
u64 start = 0;
u64 end;
atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
while (!find_first_extent_bit(dirty_pages, start, &start, &end,
mark, &cached_state)) {
bool wait_writeback = false;
err = convert_extent_bit(dirty_pages, start, end,
EXTENT_NEED_WAIT,
mark, &cached_state);
/*
* convert_extent_bit can return -ENOMEM, which is most of the
* time a temporary error. So when it happens, ignore the error
* and wait for writeback of this range to finish - because we
* failed to set the bit EXTENT_NEED_WAIT for the range, a call
* to __btrfs_wait_marked_extents() would not know that
* writeback for this range started and therefore wouldn't
* wait for it to finish - we don't want to commit a
* superblock that points to btree nodes/leafs for which
* writeback hasn't finished yet (and without errors).
* We cleanup any entries left in the io tree when committing
* the transaction (through extent_io_tree_release()).
*/
if (err == -ENOMEM) {
err = 0;
wait_writeback = true;
}
if (!err)
err = filemap_fdatawrite_range(mapping, start, end);
if (err)
werr = err;
else if (wait_writeback)
werr = filemap_fdatawait_range(mapping, start, end);
free_extent_state(cached_state);
cached_state = NULL;
cond_resched();
start = end + 1;
}
atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
return werr;
}
/*
* when btree blocks are allocated, they have some corresponding bits set for
* them in one of two extent_io trees. This is used to make sure all of
* those extents are on disk for transaction or log commit. We wait
* on all the pages and clear them from the dirty pages state tree
*/
static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
struct extent_io_tree *dirty_pages)
{
int err = 0;
int werr = 0;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
struct extent_state *cached_state = NULL;
u64 start = 0;
u64 end;
while (!find_first_extent_bit(dirty_pages, start, &start, &end,
EXTENT_NEED_WAIT, &cached_state)) {
/*
* Ignore -ENOMEM errors returned by clear_extent_bit().
* When committing the transaction, we'll remove any entries
* left in the io tree. For a log commit, we don't remove them
* after committing the log because the tree can be accessed
* concurrently - we do it only at transaction commit time when
* it's safe to do it (through extent_io_tree_release()).
*/
err = clear_extent_bit(dirty_pages, start, end,
EXTENT_NEED_WAIT, 0, 0, &cached_state);
if (err == -ENOMEM)
err = 0;
if (!err)
err = filemap_fdatawait_range(mapping, start, end);
if (err)
werr = err;
free_extent_state(cached_state);
cached_state = NULL;
cond_resched();
start = end + 1;
}
if (err)
werr = err;
return werr;
}
int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
struct extent_io_tree *dirty_pages)
{
bool errors = false;
int err;
err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
errors = true;
if (errors && !err)
err = -EIO;
return err;
}
int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
{
struct btrfs_fs_info *fs_info = log_root->fs_info;
struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
bool errors = false;
int err;
ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
if ((mark & EXTENT_DIRTY) &&
test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
errors = true;
if ((mark & EXTENT_NEW) &&
test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
errors = true;
if (errors && !err)
err = -EIO;
return err;
}
/*
* When btree blocks are allocated the corresponding extents are marked dirty.
* This function ensures such extents are persisted on disk for transaction or
* log commit.
*
* @trans: transaction whose dirty pages we'd like to write
*/
static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
{
int ret;
int ret2;
struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
struct btrfs_fs_info *fs_info = trans->fs_info;
struct blk_plug plug;
blk_start_plug(&plug);
ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
blk_finish_plug(&plug);
ret2 = btrfs_wait_extents(fs_info, dirty_pages);
extent_io_tree_release(&trans->transaction->dirty_pages);
if (ret)
return ret;
else if (ret2)
return ret2;
else
return 0;
}
/*
* this is used to update the root pointer in the tree of tree roots.
*
* But, in the case of the extent allocation tree, updating the root
* pointer may allocate blocks which may change the root of the extent
* allocation tree.
*
* So, this loops and repeats and makes sure the cowonly root didn't
* change while the root pointer was being updated in the metadata.
*/
static int update_cowonly_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_root_bytenr;
u64 old_root_used;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *tree_root = fs_info->tree_root;
old_root_used = btrfs_root_used(&root->root_item);
while (1) {
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
if (old_root_bytenr == root->node->start &&
old_root_used == btrfs_root_used(&root->root_item))
break;
btrfs_set_root_node(&root->root_item, root->node);
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
&root->root_item);
if (ret)
return ret;
old_root_used = btrfs_root_used(&root->root_item);
}
return 0;
}
/*
* update all the cowonly tree roots on disk
*
* The error handling in this function may not be obvious. Any of the
* failures will cause the file system to go offline. We still need
* to clean up the delayed refs.
*/
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
struct list_head *io_bgs = &trans->transaction->io_bgs;
struct list_head *next;
struct extent_buffer *eb;
int ret;
eb = btrfs_lock_root_node(fs_info->tree_root);
ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
0, &eb);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
if (ret)
return ret;
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
return ret;
ret = btrfs_run_dev_stats(trans);
if (ret)
return ret;
ret = btrfs_run_dev_replace(trans);
if (ret)
return ret;
ret = btrfs_run_qgroups(trans);
if (ret)
return ret;
ret = btrfs_setup_space_cache(trans);
if (ret)
return ret;
/* run_qgroups might have added some more refs */
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
return ret;
again:
while (!list_empty(&fs_info->dirty_cowonly_roots)) {
struct btrfs_root *root;
next = fs_info->dirty_cowonly_roots.next;
list_del_init(next);
root = list_entry(next, struct btrfs_root, dirty_list);
clear_bit(BTRFS_ROOT_DIRTY, &root->state);
if (root != fs_info->extent_root)
list_add_tail(&root->dirty_list,
&trans->transaction->switch_commits);
ret = update_cowonly_root(trans, root);
if (ret)
return ret;
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
return ret;
}
while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
ret = btrfs_write_dirty_block_groups(trans);
if (ret)
return ret;
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
return ret;
}
if (!list_empty(&fs_info->dirty_cowonly_roots))
goto again;
list_add_tail(&fs_info->extent_root->dirty_list,
&trans->transaction->switch_commits);
/* Update dev-replace pointer once everything is committed */
fs_info->dev_replace.committed_cursor_left =
fs_info->dev_replace.cursor_left_last_write_of_item;
return 0;
}
/*
* dead roots are old snapshots that need to be deleted. This allocates
* a dirty root struct and adds it into the list of dead roots that need to
* be deleted
*/
void btrfs_add_dead_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
spin_lock(&fs_info->trans_lock);
if (list_empty(&root->root_list))
list_add_tail(&root->root_list, &fs_info->dead_roots);
spin_unlock(&fs_info->trans_lock);
}
/*
* update all the cowonly tree roots on disk
*/
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *gang[8];
int i;
int ret;
int err = 0;
spin_lock(&fs_info->fs_roots_radix_lock);
while (1) {
ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
(void **)gang, 0,
ARRAY_SIZE(gang),
BTRFS_ROOT_TRANS_TAG);
if (ret == 0)
break;
for (i = 0; i < ret; i++) {
struct btrfs_root *root = gang[i];
radix_tree_tag_clear(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&fs_info->fs_roots_radix_lock);
btrfs_free_log(trans, root);
btrfs_update_reloc_root(trans, root);
btrfs_save_ino_cache(root, trans);
/* see comments in should_cow_block() */
clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
smp_mb__after_atomic();
if (root->commit_root != root->node) {
list_add_tail(&root->dirty_list,
&trans->transaction->switch_commits);
btrfs_set_root_node(&root->root_item,
root->node);
}
err = btrfs_update_root(trans, fs_info->tree_root,
&root->root_key,
&root->root_item);
spin_lock(&fs_info->fs_roots_radix_lock);
if (err)
break;
btrfs_qgroup_free_meta_all_pertrans(root);
}
}
spin_unlock(&fs_info->fs_roots_radix_lock);
return err;
}
/*
* defrag a given btree.
* Every leaf in the btree is read and defragged.
*/
int btrfs_defrag_root(struct btrfs_root *root)
{
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_trans_handle *trans;
int ret;
if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
return 0;
while (1) {
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
ret = btrfs_defrag_leaves(trans, root);
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(info);
cond_resched();
if (btrfs_fs_closing(info) || ret != -EAGAIN)
break;
if (btrfs_defrag_cancelled(info)) {
btrfs_debug(info, "defrag_root cancelled");
ret = -EAGAIN;
break;
}
}
clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
return ret;
}
/*
* Do all special snapshot related qgroup dirty hack.
*
* Will do all needed qgroup inherit and dirty hack like switch commit
* roots inside one transaction and write all btree into disk, to make
* qgroup works.
*/
static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
struct btrfs_root *src,
struct btrfs_root *parent,
struct btrfs_qgroup_inherit *inherit,
u64 dst_objectid)
{
struct btrfs_fs_info *fs_info = src->fs_info;
int ret;
/*
* Save some performance in the case that qgroups are not
* enabled. If this check races with the ioctl, rescan will
* kick in anyway.
*/
if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
return 0;
/*
* Ensure dirty @src will be committed. Or, after coming
* commit_fs_roots() and switch_commit_roots(), any dirty but not
* recorded root will never be updated again, causing an outdated root
* item.
*/
record_root_in_trans(trans, src, 1);
/*
* We are going to commit transaction, see btrfs_commit_transaction()
* comment for reason locking tree_log_mutex
*/
mutex_lock(&fs_info->tree_log_mutex);
ret = commit_fs_roots(trans);
if (ret)
goto out;
ret = btrfs_qgroup_account_extents(trans);
if (ret < 0)
goto out;
/* Now qgroup are all updated, we can inherit it to new qgroups */
ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
inherit);
if (ret < 0)
goto out;
/*
* Now we do a simplified commit transaction, which will:
* 1) commit all subvolume and extent tree
* To ensure all subvolume and extent tree have a valid
* commit_root to accounting later insert_dir_item()
* 2) write all btree blocks onto disk
* This is to make sure later btree modification will be cowed
* Or commit_root can be populated and cause wrong qgroup numbers
* In this simplified commit, we don't really care about other trees
* like chunk and root tree, as they won't affect qgroup.
* And we don't write super to avoid half committed status.
*/
ret = commit_cowonly_roots(trans);
if (ret)
goto out;
switch_commit_roots(trans->transaction);
ret = btrfs_write_and_wait_transaction(trans);
if (ret)
btrfs_handle_fs_error(fs_info, ret,
"Error while writing out transaction for qgroup");
out:
mutex_unlock(&fs_info->tree_log_mutex);
/*
* Force parent root to be updated, as we recorded it before so its
* last_trans == cur_transid.
* Or it won't be committed again onto disk after later
* insert_dir_item()
*/
if (!ret)
record_root_in_trans(trans, parent, 1);
return ret;
}
/*
* new snapshots need to be created at a very specific time in the
* transaction commit. This does the actual creation.
*
* Note:
* If the error which may affect the commitment of the current transaction
* happens, we should return the error number. If the error which just affect
* the creation of the pending snapshots, just return 0.
*/
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
struct btrfs_pending_snapshot *pending)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_key key;
struct btrfs_root_item *new_root_item;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *root = pending->root;
struct btrfs_root *parent_root;
struct btrfs_block_rsv *rsv;
struct inode *parent_inode;
struct btrfs_path *path;
struct btrfs_dir_item *dir_item;
struct dentry *dentry;
struct extent_buffer *tmp;
struct extent_buffer *old;
struct timespec64 cur_time;
int ret = 0;
u64 to_reserve = 0;
u64 index = 0;
u64 objectid;
u64 root_flags;
uuid_le new_uuid;
ASSERT(pending->path);
path = pending->path;
ASSERT(pending->root_item);
new_root_item = pending->root_item;
pending->error = btrfs_find_free_objectid(tree_root, &objectid);
if (pending->error)
goto no_free_objectid;
/*
* Make qgroup to skip current new snapshot's qgroupid, as it is
* accounted by later btrfs_qgroup_inherit().
*/
btrfs_set_skip_qgroup(trans, objectid);
btrfs_reloc_pre_snapshot(pending, &to_reserve);
if (to_reserve > 0) {
pending->error = btrfs_block_rsv_add(root,
&pending->block_rsv,
to_reserve,
BTRFS_RESERVE_NO_FLUSH);
if (pending->error)
goto clear_skip_qgroup;
}
key.objectid = objectid;
key.offset = (u64)-1;
key.type = BTRFS_ROOT_ITEM_KEY;
rsv = trans->block_rsv;
trans->block_rsv = &pending->block_rsv;
trans->bytes_reserved = trans->block_rsv->reserved;
trace_btrfs_space_reservation(fs_info, "transaction",
trans->transid,
trans->bytes_reserved, 1);
dentry = pending->dentry;
parent_inode = pending->dir;
parent_root = BTRFS_I(parent_inode)->root;
record_root_in_trans(trans, parent_root, 0);
cur_time = current_time(parent_inode);
/*
* insert the directory item
*/
ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
BUG_ON(ret); /* -ENOMEM */
/* check if there is a file/dir which has the same name. */
dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
btrfs_ino(BTRFS_I(parent_inode)),
dentry->d_name.name,
dentry->d_name.len, 0);
if (dir_item != NULL && !IS_ERR(dir_item)) {
pending->error = -EEXIST;
goto dir_item_existed;
} else if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
btrfs_abort_transaction(trans, ret);
goto fail;
}
btrfs_release_path(path);
/*
* pull in the delayed directory update
* and the delayed inode item
* otherwise we corrupt the FS during
* snapshot
*/
ret = btrfs_run_delayed_items(trans);
if (ret) { /* Transaction aborted */
btrfs_abort_transaction(trans, ret);
goto fail;
}
record_root_in_trans(trans, root, 0);
btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
btrfs_check_and_init_root_item(new_root_item);
root_flags = btrfs_root_flags(new_root_item);
if (pending->readonly)
root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
else
root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
btrfs_set_root_flags(new_root_item, root_flags);
btrfs_set_root_generation_v2(new_root_item,
trans->transid);
uuid_le_gen(&new_uuid);
memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
memcpy(new_root_item->parent_uuid, root->root_item.uuid,
BTRFS_UUID_SIZE);
if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
memset(new_root_item->received_uuid, 0,
sizeof(new_root_item->received_uuid));
memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
btrfs_set_root_stransid(new_root_item, 0);
btrfs_set_root_rtransid(new_root_item, 0);
}
btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
btrfs_set_root_otransid(new_root_item, trans->transid);
old = btrfs_lock_root_node(root);
ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
if (ret) {
btrfs_tree_unlock(old);
free_extent_buffer(old);
btrfs_abort_transaction(trans, ret);
goto fail;
}
btrfs_set_lock_blocking_write(old);
ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
/* clean up in any case */
btrfs_tree_unlock(old);
free_extent_buffer(old);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
/* see comments in should_cow_block() */
set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
smp_wmb();
btrfs_set_root_node(new_root_item, tmp);
/* record when the snapshot was created in key.offset */
key.offset = trans->transid;
ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
btrfs_tree_unlock(tmp);
free_extent_buffer(tmp);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
/*
* insert root back/forward references
*/
ret = btrfs_add_root_ref(trans, objectid,
parent_root->root_key.objectid,
btrfs_ino(BTRFS_I(parent_inode)), index,
dentry->d_name.name, dentry->d_name.len);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
key.offset = (u64)-1;
pending->snap = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(pending->snap)) {
ret = PTR_ERR(pending->snap);
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = btrfs_reloc_post_snapshot(trans, pending);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
/*
* Do special qgroup accounting for snapshot, as we do some qgroup
* snapshot hack to do fast snapshot.
* To co-operate with that hack, we do hack again.
* Or snapshot will be greatly slowed down by a subtree qgroup rescan
*/
ret = qgroup_account_snapshot(trans, root, parent_root,
pending->inherit, objectid);
if (ret < 0)
goto fail;
ret = btrfs_insert_dir_item(trans, dentry->d_name.name,
dentry->d_name.len, BTRFS_I(parent_inode),
&key, BTRFS_FT_DIR, index);
/* We have check then name at the beginning, so it is impossible. */
BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
dentry->d_name.len * 2);
parent_inode->i_mtime = parent_inode->i_ctime =
current_time(parent_inode);
ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = btrfs_uuid_tree_add(trans, new_uuid.b, BTRFS_UUID_KEY_SUBVOL,
objectid);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
BTRFS_UUID_KEY_RECEIVED_SUBVOL,
objectid);
if (ret && ret != -EEXIST) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
}
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
fail:
pending->error = ret;
dir_item_existed:
trans->block_rsv = rsv;
trans->bytes_reserved = 0;
clear_skip_qgroup:
btrfs_clear_skip_qgroup(trans);
no_free_objectid:
kfree(new_root_item);
pending->root_item = NULL;
btrfs_free_path(path);
pending->path = NULL;
return ret;
}
/*
* create all the snapshots we've scheduled for creation
*/
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
{
struct btrfs_pending_snapshot *pending, *next;
struct list_head *head = &trans->transaction->pending_snapshots;
int ret = 0;
list_for_each_entry_safe(pending, next, head, list) {
list_del(&pending->list);
ret = create_pending_snapshot(trans, pending);
if (ret)
break;
}
return ret;
}
static void update_super_roots(struct btrfs_fs_info *fs_info)
{
struct btrfs_root_item *root_item;
struct btrfs_super_block *super;
super = fs_info->super_copy;
root_item = &fs_info->chunk_root->root_item;
super->chunk_root = root_item->bytenr;
super->chunk_root_generation = root_item->generation;
super->chunk_root_level = root_item->level;
root_item = &fs_info->tree_root->root_item;
super->root = root_item->bytenr;
super->generation = root_item->generation;
super->root_level = root_item->level;
if (btrfs_test_opt(fs_info, SPACE_CACHE))
super->cache_generation = root_item->generation;
if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
super->uuid_tree_generation = root_item->generation;
}
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
struct btrfs_transaction *trans;
int ret = 0;
spin_lock(&info->trans_lock);
trans = info->running_transaction;
if (trans)
ret = (trans->state >= TRANS_STATE_COMMIT_START);
spin_unlock(&info->trans_lock);
return ret;
}
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
struct btrfs_transaction *trans;
int ret = 0;
spin_lock(&info->trans_lock);
trans = info->running_transaction;
if (trans)
ret = is_transaction_blocked(trans);
spin_unlock(&info->trans_lock);
return ret;
}
/*
* wait for the current transaction commit to start and block subsequent
* transaction joins
*/
static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info,
struct btrfs_transaction *trans)
{
wait_event(fs_info->transaction_blocked_wait,
trans->state >= TRANS_STATE_COMMIT_START || trans->aborted);
}
/*
* wait for the current transaction to start and then become unblocked.
* caller holds ref.
*/
static void wait_current_trans_commit_start_and_unblock(
struct btrfs_fs_info *fs_info,
struct btrfs_transaction *trans)
{
wait_event(fs_info->transaction_wait,
trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted);
}
/*
* commit transactions asynchronously. once btrfs_commit_transaction_async
* returns, any subsequent transaction will not be allowed to join.
*/
struct btrfs_async_commit {
struct btrfs_trans_handle *newtrans;
struct work_struct work;
};
static void do_async_commit(struct work_struct *work)
{
struct btrfs_async_commit *ac =
container_of(work, struct btrfs_async_commit, work);
/*
* We've got freeze protection passed with the transaction.
* Tell lockdep about it.
*/
if (ac->newtrans->type & __TRANS_FREEZABLE)
__sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS);
current->journal_info = ac->newtrans;
btrfs_commit_transaction(ac->newtrans);
kfree(ac);
}
int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
int wait_for_unblock)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_async_commit *ac;
struct btrfs_transaction *cur_trans;
ac = kmalloc(sizeof(*ac), GFP_NOFS);
if (!ac)
return -ENOMEM;
INIT_WORK(&ac->work, do_async_commit);
ac->newtrans = btrfs_join_transaction(trans->root);
if (IS_ERR(ac->newtrans)) {
int err = PTR_ERR(ac->newtrans);
kfree(ac);
return err;
}
/* take transaction reference */
cur_trans = trans->transaction;
refcount_inc(&cur_trans->use_count);
btrfs_end_transaction(trans);
/*
* Tell lockdep we've released the freeze rwsem, since the
* async commit thread will be the one to unlock it.
*/
if (ac->newtrans->type & __TRANS_FREEZABLE)
__sb_writers_release(fs_info->sb, SB_FREEZE_FS);
schedule_work(&ac->work);
/* wait for transaction to start and unblock */
if (wait_for_unblock)
wait_current_trans_commit_start_and_unblock(fs_info, cur_trans);
else
wait_current_trans_commit_start(fs_info, cur_trans);
if (current->journal_info == trans)
current->journal_info = NULL;
btrfs_put_transaction(cur_trans);
return 0;
}
static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
WARN_ON(refcount_read(&trans->use_count) > 1);
btrfs_abort_transaction(trans, err);
spin_lock(&fs_info->trans_lock);
/*
* If the transaction is removed from the list, it means this
* transaction has been committed successfully, so it is impossible
* to call the cleanup function.
*/
BUG_ON(list_empty(&cur_trans->list));
list_del_init(&cur_trans->list);
if (cur_trans == fs_info->running_transaction) {
cur_trans->state = TRANS_STATE_COMMIT_DOING;
spin_unlock(&fs_info->trans_lock);
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
spin_lock(&fs_info->trans_lock);
}
spin_unlock(&fs_info->trans_lock);
btrfs_cleanup_one_transaction(trans->transaction, fs_info);
spin_lock(&fs_info->trans_lock);
if (cur_trans == fs_info->running_transaction)
fs_info->running_transaction = NULL;
spin_unlock(&fs_info->trans_lock);
if (trans->type & __TRANS_FREEZABLE)
sb_end_intwrite(fs_info->sb);
btrfs_put_transaction(cur_trans);
btrfs_put_transaction(cur_trans);
trace_btrfs_transaction_commit(trans->root);
if (current->journal_info == trans)
current->journal_info = NULL;
btrfs_scrub_cancel(fs_info);
kmem_cache_free(btrfs_trans_handle_cachep, trans);
}
/*
* Release reserved delayed ref space of all pending block groups of the
* transaction and remove them from the list
*/
static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *block_group, *tmp;
list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
btrfs_delayed_refs_rsv_release(fs_info, 1);
list_del_init(&block_group->bg_list);
}
}
static inline int btrfs_start_delalloc_flush(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
/*
* We use writeback_inodes_sb here because if we used
* btrfs_start_delalloc_roots we would deadlock with fs freeze.
* Currently are holding the fs freeze lock, if we do an async flush
* we'll do btrfs_join_transaction() and deadlock because we need to
* wait for the fs freeze lock. Using the direct flushing we benefit
* from already being in a transaction and our join_transaction doesn't
* have to re-take the fs freeze lock.
*/
if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) {
writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
} else {
struct btrfs_pending_snapshot *pending;
struct list_head *head = &trans->transaction->pending_snapshots;
/*
* Flush dellaloc for any root that is going to be snapshotted.
* This is done to avoid a corrupted version of files, in the
* snapshots, that had both buffered and direct IO writes (even
* if they were done sequentially) due to an unordered update of
* the inode's size on disk.
*/
list_for_each_entry(pending, head, list) {
int ret;
ret = btrfs_start_delalloc_snapshot(pending->root);
if (ret)
return ret;
}
}
return 0;
}
static inline void btrfs_wait_delalloc_flush(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) {
btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
} else {
struct btrfs_pending_snapshot *pending;
struct list_head *head = &trans->transaction->pending_snapshots;
/*
* Wait for any dellaloc that we started previously for the roots
* that are going to be snapshotted. This is to avoid a corrupted
* version of files in the snapshots that had both buffered and
* direct IO writes (even if they were done sequentially).
*/
list_for_each_entry(pending, head, list)
btrfs_wait_ordered_extents(pending->root,
U64_MAX, 0, U64_MAX);
}
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_transaction *prev_trans = NULL;
int ret;
/* Stop the commit early if ->aborted is set */
if (unlikely(READ_ONCE(cur_trans->aborted))) {
ret = cur_trans->aborted;
btrfs_end_transaction(trans);
return ret;
}
btrfs_trans_release_metadata(trans);
trans->block_rsv = NULL;
/* make a pass through all the delayed refs we have so far
* any runnings procs may add more while we are here
*/
ret = btrfs_run_delayed_refs(trans, 0);
if (ret) {
btrfs_end_transaction(trans);
return ret;
}
cur_trans = trans->transaction;
/*
* set the flushing flag so procs in this transaction have to
* start sending their work down.
*/
cur_trans->delayed_refs.flushing = 1;
smp_wmb();
btrfs_create_pending_block_groups(trans);
ret = btrfs_run_delayed_refs(trans, 0);
if (ret) {
btrfs_end_transaction(trans);
return ret;
}
if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
int run_it = 0;
/* this mutex is also taken before trying to set
* block groups readonly. We need to make sure
* that nobody has set a block group readonly
* after a extents from that block group have been
* allocated for cache files. btrfs_set_block_group_ro
* will wait for the transaction to commit if it
* finds BTRFS_TRANS_DIRTY_BG_RUN set.
*
* The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
* only one process starts all the block group IO. It wouldn't
* hurt to have more than one go through, but there's no
* real advantage to it either.
*/
mutex_lock(&fs_info->ro_block_group_mutex);
if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
&cur_trans->flags))
run_it = 1;
mutex_unlock(&fs_info->ro_block_group_mutex);
if (run_it) {
ret = btrfs_start_dirty_block_groups(trans);
if (ret) {
btrfs_end_transaction(trans);
return ret;
}
}
}
spin_lock(&fs_info->trans_lock);
if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
spin_unlock(&fs_info->trans_lock);
refcount_inc(&cur_trans->use_count);
ret = btrfs_end_transaction(trans);
wait_for_commit(cur_trans);
if (unlikely(cur_trans->aborted))
ret = cur_trans->aborted;
btrfs_put_transaction(cur_trans);
return ret;
}
cur_trans->state = TRANS_STATE_COMMIT_START;
wake_up(&fs_info->transaction_blocked_wait);
if (cur_trans->list.prev != &fs_info->trans_list) {
prev_trans = list_entry(cur_trans->list.prev,
struct btrfs_transaction, list);
if (prev_trans->state != TRANS_STATE_COMPLETED) {
refcount_inc(&prev_trans->use_count);
spin_unlock(&fs_info->trans_lock);
wait_for_commit(prev_trans);
ret = prev_trans->aborted;
btrfs_put_transaction(prev_trans);
if (ret)
goto cleanup_transaction;
} else {
spin_unlock(&fs_info->trans_lock);
}
} else {
spin_unlock(&fs_info->trans_lock);
}
extwriter_counter_dec(cur_trans, trans->type);
ret = btrfs_start_delalloc_flush(trans);
if (ret)
goto cleanup_transaction;
ret = btrfs_run_delayed_items(trans);
if (ret)
goto cleanup_transaction;
wait_event(cur_trans->writer_wait,
extwriter_counter_read(cur_trans) == 0);
/* some pending stuffs might be added after the previous flush. */
ret = btrfs_run_delayed_items(trans);
if (ret)
goto cleanup_transaction;
btrfs_wait_delalloc_flush(trans);
btrfs_scrub_pause(fs_info);
/*
* Ok now we need to make sure to block out any other joins while we
* commit the transaction. We could have started a join before setting
* COMMIT_DOING so make sure to wait for num_writers to == 1 again.
*/
spin_lock(&fs_info->trans_lock);
cur_trans->state = TRANS_STATE_COMMIT_DOING;
spin_unlock(&fs_info->trans_lock);
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
/* ->aborted might be set after the previous check, so check it */
if (unlikely(READ_ONCE(cur_trans->aborted))) {
ret = cur_trans->aborted;
goto scrub_continue;
}
/*
* the reloc mutex makes sure that we stop
* the balancing code from coming in and moving
* extents around in the middle of the commit
*/
mutex_lock(&fs_info->reloc_mutex);
/*
* We needn't worry about the delayed items because we will
* deal with them in create_pending_snapshot(), which is the
* core function of the snapshot creation.
*/
ret = create_pending_snapshots(trans);
if (ret) {
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
/*
* We insert the dir indexes of the snapshots and update the inode
* of the snapshots' parents after the snapshot creation, so there
* are some delayed items which are not dealt with. Now deal with
* them.
*
* We needn't worry that this operation will corrupt the snapshots,
* because all the tree which are snapshoted will be forced to COW
* the nodes and leaves.
*/
ret = btrfs_run_delayed_items(trans);
if (ret) {
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret) {
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
/*
* make sure none of the code above managed to slip in a
* delayed item
*/
btrfs_assert_delayed_root_empty(fs_info);
WARN_ON(cur_trans != trans->transaction);
/* btrfs_commit_tree_roots is responsible for getting the
* various roots consistent with each other. Every pointer
* in the tree of tree roots has to point to the most up to date
* root for every subvolume and other tree. So, we have to keep
* the tree logging code from jumping in and changing any
* of the trees.
*
* At this point in the commit, there can't be any tree-log
* writers, but a little lower down we drop the trans mutex
* and let new people in. By holding the tree_log_mutex
* from now until after the super is written, we avoid races
* with the tree-log code.
*/
mutex_lock(&fs_info->tree_log_mutex);
ret = commit_fs_roots(trans);
if (ret) {
mutex_unlock(&fs_info->tree_log_mutex);
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
/*
* Since the transaction is done, we can apply the pending changes
* before the next transaction.
*/
btrfs_apply_pending_changes(fs_info);
/* commit_fs_roots gets rid of all the tree log roots, it is now
* safe to free the root of tree log roots
*/
btrfs_free_log_root_tree(trans, fs_info);
/*
* commit_fs_roots() can call btrfs_save_ino_cache(), which generates
* new delayed refs. Must handle them or qgroup can be wrong.
*/
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret) {
mutex_unlock(&fs_info->tree_log_mutex);
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
/*
* Since fs roots are all committed, we can get a quite accurate
* new_roots. So let's do quota accounting.
*/
ret = btrfs_qgroup_account_extents(trans);
if (ret < 0) {
mutex_unlock(&fs_info->tree_log_mutex);
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
ret = commit_cowonly_roots(trans);
if (ret) {
mutex_unlock(&fs_info->tree_log_mutex);
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
/*
* The tasks which save the space cache and inode cache may also
* update ->aborted, check it.
*/
if (unlikely(READ_ONCE(cur_trans->aborted))) {
ret = cur_trans->aborted;
mutex_unlock(&fs_info->tree_log_mutex);
mutex_unlock(&fs_info->reloc_mutex);
goto scrub_continue;
}
btrfs_prepare_extent_commit(fs_info);
cur_trans = fs_info->running_transaction;
btrfs_set_root_node(&fs_info->tree_root->root_item,
fs_info->tree_root->node);
list_add_tail(&fs_info->tree_root->dirty_list,
&cur_trans->switch_commits);
btrfs_set_root_node(&fs_info->chunk_root->root_item,
fs_info->chunk_root->node);
list_add_tail(&fs_info->chunk_root->dirty_list,
&cur_trans->switch_commits);
switch_commit_roots(cur_trans);
ASSERT(list_empty(&cur_trans->dirty_bgs));
ASSERT(list_empty(&cur_trans->io_bgs));
update_super_roots(fs_info);
btrfs_set_super_log_root(fs_info->super_copy, 0);
btrfs_set_super_log_root_level(fs_info->super_copy, 0);
memcpy(fs_info->super_for_commit, fs_info->super_copy,
sizeof(*fs_info->super_copy));
btrfs_commit_device_sizes(cur_trans);
clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
btrfs_trans_release_chunk_metadata(trans);
spin_lock(&fs_info->trans_lock);
cur_trans->state = TRANS_STATE_UNBLOCKED;
fs_info->running_transaction = NULL;
spin_unlock(&fs_info->trans_lock);
mutex_unlock(&fs_info->reloc_mutex);
wake_up(&fs_info->transaction_wait);
ret = btrfs_write_and_wait_transaction(trans);
if (ret) {
btrfs_handle_fs_error(fs_info, ret,
"Error while writing out transaction");
mutex_unlock(&fs_info->tree_log_mutex);
goto scrub_continue;
}
ret = write_all_supers(fs_info, 0);
/*
* the super is written, we can safely allow the tree-loggers
* to go about their business
*/
mutex_unlock(&fs_info->tree_log_mutex);
if (ret)
goto scrub_continue;
btrfs_finish_extent_commit(trans);
if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
btrfs_clear_space_info_full(fs_info);
fs_info->last_trans_committed = cur_trans->transid;
/*
* We needn't acquire the lock here because there is no other task
* which can change it.
*/
cur_trans->state = TRANS_STATE_COMPLETED;
wake_up(&cur_trans->commit_wait);
clear_bit(BTRFS_FS_NEED_ASYNC_COMMIT, &fs_info->flags);
spin_lock(&fs_info->trans_lock);
list_del_init(&cur_trans->list);
spin_unlock(&fs_info->trans_lock);
btrfs_put_transaction(cur_trans);
btrfs_put_transaction(cur_trans);
if (trans->type & __TRANS_FREEZABLE)
sb_end_intwrite(fs_info->sb);
trace_btrfs_transaction_commit(trans->root);
btrfs_scrub_continue(fs_info);
if (current->journal_info == trans)
current->journal_info = NULL;
kmem_cache_free(btrfs_trans_handle_cachep, trans);
return ret;
scrub_continue:
btrfs_scrub_continue(fs_info);
cleanup_transaction:
btrfs_trans_release_metadata(trans);
btrfs_cleanup_pending_block_groups(trans);
btrfs_trans_release_chunk_metadata(trans);
trans->block_rsv = NULL;
btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
if (current->journal_info == trans)
current->journal_info = NULL;
cleanup_transaction(trans, ret);
return ret;
}
/*
* return < 0 if error
* 0 if there are no more dead_roots at the time of call
* 1 there are more to be processed, call me again
*
* The return value indicates there are certainly more snapshots to delete, but
* if there comes a new one during processing, it may return 0. We don't mind,
* because btrfs_commit_super will poke cleaner thread and it will process it a
* few seconds later.
*/
int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
{
int ret;
struct btrfs_fs_info *fs_info = root->fs_info;
spin_lock(&fs_info->trans_lock);
if (list_empty(&fs_info->dead_roots)) {
spin_unlock(&fs_info->trans_lock);
return 0;
}
root = list_first_entry(&fs_info->dead_roots,
struct btrfs_root, root_list);
list_del_init(&root->root_list);
spin_unlock(&fs_info->trans_lock);
btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
btrfs_kill_all_delayed_nodes(root);
if (btrfs_header_backref_rev(root->node) <
BTRFS_MIXED_BACKREF_REV)
ret = btrfs_drop_snapshot(root, NULL, 0, 0);
else
ret = btrfs_drop_snapshot(root, NULL, 1, 0);
return (ret < 0) ? 0 : 1;
}
void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
{
unsigned long prev;
unsigned long bit;
prev = xchg(&fs_info->pending_changes, 0);
if (!prev)
return;
bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
if (prev & bit)
btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
prev &= ~bit;
bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
if (prev & bit)
btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
prev &= ~bit;
bit = 1 << BTRFS_PENDING_COMMIT;
if (prev & bit)
btrfs_debug(fs_info, "pending commit done");
prev &= ~bit;
if (prev)
btrfs_warn(fs_info,
"unknown pending changes left 0x%lx, ignoring", prev);
}
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