mirror of https://gitee.com/openkylin/linux.git
2488 lines
75 KiB
C
2488 lines
75 KiB
C
/*
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* linux/fs/jbd2/transaction.c
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*
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* Written by Stephen C. Tweedie <sct@redhat.com>, 1998
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*
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* Copyright 1998 Red Hat corp --- All Rights Reserved
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*
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License, version 2, or at your
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* option, any later version, incorporated herein by reference.
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*
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* Generic filesystem transaction handling code; part of the ext2fs
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* journaling system.
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*
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* This file manages transactions (compound commits managed by the
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* journaling code) and handles (individual atomic operations by the
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* filesystem).
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/jbd2.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/timer.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/hrtimer.h>
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#include <linux/backing-dev.h>
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#include <linux/bug.h>
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#include <linux/module.h>
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#include <trace/events/jbd2.h>
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static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
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static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
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static struct kmem_cache *transaction_cache;
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int __init jbd2_journal_init_transaction_cache(void)
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{
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J_ASSERT(!transaction_cache);
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transaction_cache = kmem_cache_create("jbd2_transaction_s",
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sizeof(transaction_t),
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0,
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SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
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NULL);
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if (transaction_cache)
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return 0;
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return -ENOMEM;
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}
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void jbd2_journal_destroy_transaction_cache(void)
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{
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if (transaction_cache) {
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kmem_cache_destroy(transaction_cache);
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transaction_cache = NULL;
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}
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}
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void jbd2_journal_free_transaction(transaction_t *transaction)
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{
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if (unlikely(ZERO_OR_NULL_PTR(transaction)))
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return;
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kmem_cache_free(transaction_cache, transaction);
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}
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/*
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* jbd2_get_transaction: obtain a new transaction_t object.
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*
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* Simply allocate and initialise a new transaction. Create it in
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* RUNNING state and add it to the current journal (which should not
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* have an existing running transaction: we only make a new transaction
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* once we have started to commit the old one).
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*
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* Preconditions:
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* The journal MUST be locked. We don't perform atomic mallocs on the
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* new transaction and we can't block without protecting against other
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* processes trying to touch the journal while it is in transition.
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*
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*/
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static transaction_t *
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jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
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{
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transaction->t_journal = journal;
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transaction->t_state = T_RUNNING;
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transaction->t_start_time = ktime_get();
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transaction->t_tid = journal->j_transaction_sequence++;
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transaction->t_expires = jiffies + journal->j_commit_interval;
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spin_lock_init(&transaction->t_handle_lock);
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atomic_set(&transaction->t_updates, 0);
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atomic_set(&transaction->t_outstanding_credits,
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atomic_read(&journal->j_reserved_credits));
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atomic_set(&transaction->t_handle_count, 0);
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INIT_LIST_HEAD(&transaction->t_inode_list);
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INIT_LIST_HEAD(&transaction->t_private_list);
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/* Set up the commit timer for the new transaction. */
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journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires);
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add_timer(&journal->j_commit_timer);
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J_ASSERT(journal->j_running_transaction == NULL);
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journal->j_running_transaction = transaction;
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transaction->t_max_wait = 0;
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transaction->t_start = jiffies;
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transaction->t_requested = 0;
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return transaction;
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}
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/*
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* Handle management.
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*
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* A handle_t is an object which represents a single atomic update to a
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* filesystem, and which tracks all of the modifications which form part
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* of that one update.
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*/
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/*
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* Update transaction's maximum wait time, if debugging is enabled.
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*
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* In order for t_max_wait to be reliable, it must be protected by a
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* lock. But doing so will mean that start_this_handle() can not be
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* run in parallel on SMP systems, which limits our scalability. So
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* unless debugging is enabled, we no longer update t_max_wait, which
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* means that maximum wait time reported by the jbd2_run_stats
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* tracepoint will always be zero.
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*/
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static inline void update_t_max_wait(transaction_t *transaction,
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unsigned long ts)
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{
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#ifdef CONFIG_JBD2_DEBUG
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if (jbd2_journal_enable_debug &&
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time_after(transaction->t_start, ts)) {
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ts = jbd2_time_diff(ts, transaction->t_start);
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spin_lock(&transaction->t_handle_lock);
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if (ts > transaction->t_max_wait)
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transaction->t_max_wait = ts;
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spin_unlock(&transaction->t_handle_lock);
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}
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#endif
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}
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/*
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* Wait until running transaction passes T_LOCKED state. Also starts the commit
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* if needed. The function expects running transaction to exist and releases
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* j_state_lock.
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*/
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static void wait_transaction_locked(journal_t *journal)
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__releases(journal->j_state_lock)
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{
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DEFINE_WAIT(wait);
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int need_to_start;
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tid_t tid = journal->j_running_transaction->t_tid;
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prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
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TASK_UNINTERRUPTIBLE);
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need_to_start = !tid_geq(journal->j_commit_request, tid);
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read_unlock(&journal->j_state_lock);
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if (need_to_start)
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jbd2_log_start_commit(journal, tid);
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schedule();
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finish_wait(&journal->j_wait_transaction_locked, &wait);
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}
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static void sub_reserved_credits(journal_t *journal, int blocks)
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{
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atomic_sub(blocks, &journal->j_reserved_credits);
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wake_up(&journal->j_wait_reserved);
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}
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/*
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* Wait until we can add credits for handle to the running transaction. Called
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* with j_state_lock held for reading. Returns 0 if handle joined the running
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* transaction. Returns 1 if we had to wait, j_state_lock is dropped, and
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* caller must retry.
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*/
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static int add_transaction_credits(journal_t *journal, int blocks,
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int rsv_blocks)
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{
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transaction_t *t = journal->j_running_transaction;
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int needed;
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int total = blocks + rsv_blocks;
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/*
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* If the current transaction is locked down for commit, wait
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* for the lock to be released.
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*/
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if (t->t_state == T_LOCKED) {
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wait_transaction_locked(journal);
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return 1;
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}
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/*
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* If there is not enough space left in the log to write all
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* potential buffers requested by this operation, we need to
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* stall pending a log checkpoint to free some more log space.
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*/
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needed = atomic_add_return(total, &t->t_outstanding_credits);
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if (needed > journal->j_max_transaction_buffers) {
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/*
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* If the current transaction is already too large,
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* then start to commit it: we can then go back and
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* attach this handle to a new transaction.
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*/
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atomic_sub(total, &t->t_outstanding_credits);
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wait_transaction_locked(journal);
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return 1;
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}
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/*
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* The commit code assumes that it can get enough log space
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* without forcing a checkpoint. This is *critical* for
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* correctness: a checkpoint of a buffer which is also
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* associated with a committing transaction creates a deadlock,
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* so commit simply cannot force through checkpoints.
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*
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* We must therefore ensure the necessary space in the journal
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* *before* starting to dirty potentially checkpointed buffers
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* in the new transaction.
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*/
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if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) {
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atomic_sub(total, &t->t_outstanding_credits);
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read_unlock(&journal->j_state_lock);
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write_lock(&journal->j_state_lock);
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if (jbd2_log_space_left(journal) < jbd2_space_needed(journal))
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__jbd2_log_wait_for_space(journal);
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write_unlock(&journal->j_state_lock);
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return 1;
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}
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/* No reservation? We are done... */
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if (!rsv_blocks)
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return 0;
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needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits);
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/* We allow at most half of a transaction to be reserved */
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if (needed > journal->j_max_transaction_buffers / 2) {
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sub_reserved_credits(journal, rsv_blocks);
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atomic_sub(total, &t->t_outstanding_credits);
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read_unlock(&journal->j_state_lock);
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wait_event(journal->j_wait_reserved,
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atomic_read(&journal->j_reserved_credits) + rsv_blocks
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<= journal->j_max_transaction_buffers / 2);
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return 1;
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}
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return 0;
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}
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/*
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* start_this_handle: Given a handle, deal with any locking or stalling
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* needed to make sure that there is enough journal space for the handle
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* to begin. Attach the handle to a transaction and set up the
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* transaction's buffer credits.
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*/
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static int start_this_handle(journal_t *journal, handle_t *handle,
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gfp_t gfp_mask)
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{
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transaction_t *transaction, *new_transaction = NULL;
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int blocks = handle->h_buffer_credits;
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int rsv_blocks = 0;
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unsigned long ts = jiffies;
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/*
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* 1/2 of transaction can be reserved so we can practically handle
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* only 1/2 of maximum transaction size per operation
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*/
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if (WARN_ON(blocks > journal->j_max_transaction_buffers / 2)) {
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printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
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current->comm, blocks,
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journal->j_max_transaction_buffers / 2);
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return -ENOSPC;
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}
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if (handle->h_rsv_handle)
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rsv_blocks = handle->h_rsv_handle->h_buffer_credits;
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alloc_transaction:
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if (!journal->j_running_transaction) {
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new_transaction = kmem_cache_zalloc(transaction_cache,
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gfp_mask);
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if (!new_transaction) {
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/*
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* If __GFP_FS is not present, then we may be
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* being called from inside the fs writeback
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* layer, so we MUST NOT fail. Since
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* __GFP_NOFAIL is going away, we will arrange
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* to retry the allocation ourselves.
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*/
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if ((gfp_mask & __GFP_FS) == 0) {
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congestion_wait(BLK_RW_ASYNC, HZ/50);
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goto alloc_transaction;
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}
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return -ENOMEM;
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}
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}
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jbd_debug(3, "New handle %p going live.\n", handle);
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/*
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* We need to hold j_state_lock until t_updates has been incremented,
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* for proper journal barrier handling
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*/
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repeat:
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read_lock(&journal->j_state_lock);
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BUG_ON(journal->j_flags & JBD2_UNMOUNT);
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if (is_journal_aborted(journal) ||
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(journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
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read_unlock(&journal->j_state_lock);
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jbd2_journal_free_transaction(new_transaction);
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return -EROFS;
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}
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/*
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* Wait on the journal's transaction barrier if necessary. Specifically
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* we allow reserved handles to proceed because otherwise commit could
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* deadlock on page writeback not being able to complete.
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*/
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if (!handle->h_reserved && journal->j_barrier_count) {
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read_unlock(&journal->j_state_lock);
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wait_event(journal->j_wait_transaction_locked,
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journal->j_barrier_count == 0);
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goto repeat;
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}
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if (!journal->j_running_transaction) {
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read_unlock(&journal->j_state_lock);
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if (!new_transaction)
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goto alloc_transaction;
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write_lock(&journal->j_state_lock);
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if (!journal->j_running_transaction &&
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(handle->h_reserved || !journal->j_barrier_count)) {
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jbd2_get_transaction(journal, new_transaction);
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new_transaction = NULL;
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}
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write_unlock(&journal->j_state_lock);
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goto repeat;
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}
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transaction = journal->j_running_transaction;
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if (!handle->h_reserved) {
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/* We may have dropped j_state_lock - restart in that case */
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if (add_transaction_credits(journal, blocks, rsv_blocks))
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goto repeat;
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} else {
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/*
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* We have handle reserved so we are allowed to join T_LOCKED
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* transaction and we don't have to check for transaction size
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* and journal space.
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*/
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sub_reserved_credits(journal, blocks);
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handle->h_reserved = 0;
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}
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/* OK, account for the buffers that this operation expects to
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* use and add the handle to the running transaction.
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*/
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update_t_max_wait(transaction, ts);
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handle->h_transaction = transaction;
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handle->h_requested_credits = blocks;
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handle->h_start_jiffies = jiffies;
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atomic_inc(&transaction->t_updates);
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atomic_inc(&transaction->t_handle_count);
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jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n",
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handle, blocks,
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atomic_read(&transaction->t_outstanding_credits),
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jbd2_log_space_left(journal));
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read_unlock(&journal->j_state_lock);
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current->journal_info = handle;
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lock_map_acquire(&handle->h_lockdep_map);
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jbd2_journal_free_transaction(new_transaction);
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return 0;
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}
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static struct lock_class_key jbd2_handle_key;
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/* Allocate a new handle. This should probably be in a slab... */
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static handle_t *new_handle(int nblocks)
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{
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handle_t *handle = jbd2_alloc_handle(GFP_NOFS);
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if (!handle)
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return NULL;
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handle->h_buffer_credits = nblocks;
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handle->h_ref = 1;
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lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
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&jbd2_handle_key, 0);
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return handle;
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}
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|
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/**
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* handle_t *jbd2_journal_start() - Obtain a new handle.
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* @journal: Journal to start transaction on.
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* @nblocks: number of block buffer we might modify
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*
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* We make sure that the transaction can guarantee at least nblocks of
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* modified buffers in the log. We block until the log can guarantee
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* that much space. Additionally, if rsv_blocks > 0, we also create another
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* handle with rsv_blocks reserved blocks in the journal. This handle is
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* is stored in h_rsv_handle. It is not attached to any particular transaction
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* and thus doesn't block transaction commit. If the caller uses this reserved
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* handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop()
|
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* on the parent handle will dispose the reserved one. Reserved handle has to
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* be converted to a normal handle using jbd2_journal_start_reserved() before
|
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* it can be used.
|
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*
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* Return a pointer to a newly allocated handle, or an ERR_PTR() value
|
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* on failure.
|
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*/
|
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handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks,
|
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gfp_t gfp_mask, unsigned int type,
|
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unsigned int line_no)
|
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{
|
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handle_t *handle = journal_current_handle();
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int err;
|
|
|
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if (!journal)
|
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return ERR_PTR(-EROFS);
|
|
|
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if (handle) {
|
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J_ASSERT(handle->h_transaction->t_journal == journal);
|
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handle->h_ref++;
|
|
return handle;
|
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}
|
|
|
|
handle = new_handle(nblocks);
|
|
if (!handle)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (rsv_blocks) {
|
|
handle_t *rsv_handle;
|
|
|
|
rsv_handle = new_handle(rsv_blocks);
|
|
if (!rsv_handle) {
|
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jbd2_free_handle(handle);
|
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return ERR_PTR(-ENOMEM);
|
|
}
|
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rsv_handle->h_reserved = 1;
|
|
rsv_handle->h_journal = journal;
|
|
handle->h_rsv_handle = rsv_handle;
|
|
}
|
|
|
|
err = start_this_handle(journal, handle, gfp_mask);
|
|
if (err < 0) {
|
|
if (handle->h_rsv_handle)
|
|
jbd2_free_handle(handle->h_rsv_handle);
|
|
jbd2_free_handle(handle);
|
|
return ERR_PTR(err);
|
|
}
|
|
handle->h_type = type;
|
|
handle->h_line_no = line_no;
|
|
trace_jbd2_handle_start(journal->j_fs_dev->bd_dev,
|
|
handle->h_transaction->t_tid, type,
|
|
line_no, nblocks);
|
|
return handle;
|
|
}
|
|
EXPORT_SYMBOL(jbd2__journal_start);
|
|
|
|
|
|
handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
|
|
{
|
|
return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, 0, 0);
|
|
}
|
|
EXPORT_SYMBOL(jbd2_journal_start);
|
|
|
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void jbd2_journal_free_reserved(handle_t *handle)
|
|
{
|
|
journal_t *journal = handle->h_journal;
|
|
|
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WARN_ON(!handle->h_reserved);
|
|
sub_reserved_credits(journal, handle->h_buffer_credits);
|
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jbd2_free_handle(handle);
|
|
}
|
|
EXPORT_SYMBOL(jbd2_journal_free_reserved);
|
|
|
|
/**
|
|
* int jbd2_journal_start_reserved(handle_t *handle) - start reserved handle
|
|
* @handle: handle to start
|
|
*
|
|
* Start handle that has been previously reserved with jbd2_journal_reserve().
|
|
* This attaches @handle to the running transaction (or creates one if there's
|
|
* not transaction running). Unlike jbd2_journal_start() this function cannot
|
|
* block on journal commit, checkpointing, or similar stuff. It can block on
|
|
* memory allocation or frozen journal though.
|
|
*
|
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* Return 0 on success, non-zero on error - handle is freed in that case.
|
|
*/
|
|
int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
|
|
unsigned int line_no)
|
|
{
|
|
journal_t *journal = handle->h_journal;
|
|
int ret = -EIO;
|
|
|
|
if (WARN_ON(!handle->h_reserved)) {
|
|
/* Someone passed in normal handle? Just stop it. */
|
|
jbd2_journal_stop(handle);
|
|
return ret;
|
|
}
|
|
/*
|
|
* Usefulness of mixing of reserved and unreserved handles is
|
|
* questionable. So far nobody seems to need it so just error out.
|
|
*/
|
|
if (WARN_ON(current->journal_info)) {
|
|
jbd2_journal_free_reserved(handle);
|
|
return ret;
|
|
}
|
|
|
|
handle->h_journal = NULL;
|
|
/*
|
|
* GFP_NOFS is here because callers are likely from writeback or
|
|
* similarly constrained call sites
|
|
*/
|
|
ret = start_this_handle(journal, handle, GFP_NOFS);
|
|
if (ret < 0) {
|
|
jbd2_journal_free_reserved(handle);
|
|
return ret;
|
|
}
|
|
handle->h_type = type;
|
|
handle->h_line_no = line_no;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(jbd2_journal_start_reserved);
|
|
|
|
/**
|
|
* int jbd2_journal_extend() - extend buffer credits.
|
|
* @handle: handle to 'extend'
|
|
* @nblocks: nr blocks to try to extend by.
|
|
*
|
|
* Some transactions, such as large extends and truncates, can be done
|
|
* atomically all at once or in several stages. The operation requests
|
|
* a credit for a number of buffer modications in advance, but can
|
|
* extend its credit if it needs more.
|
|
*
|
|
* jbd2_journal_extend tries to give the running handle more buffer credits.
|
|
* It does not guarantee that allocation - this is a best-effort only.
|
|
* The calling process MUST be able to deal cleanly with a failure to
|
|
* extend here.
|
|
*
|
|
* Return 0 on success, non-zero on failure.
|
|
*
|
|
* return code < 0 implies an error
|
|
* return code > 0 implies normal transaction-full status.
|
|
*/
|
|
int jbd2_journal_extend(handle_t *handle, int nblocks)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
int result;
|
|
int wanted;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EROFS;
|
|
journal = transaction->t_journal;
|
|
|
|
result = 1;
|
|
|
|
read_lock(&journal->j_state_lock);
|
|
|
|
/* Don't extend a locked-down transaction! */
|
|
if (transaction->t_state != T_RUNNING) {
|
|
jbd_debug(3, "denied handle %p %d blocks: "
|
|
"transaction not running\n", handle, nblocks);
|
|
goto error_out;
|
|
}
|
|
|
|
spin_lock(&transaction->t_handle_lock);
|
|
wanted = atomic_add_return(nblocks,
|
|
&transaction->t_outstanding_credits);
|
|
|
|
if (wanted > journal->j_max_transaction_buffers) {
|
|
jbd_debug(3, "denied handle %p %d blocks: "
|
|
"transaction too large\n", handle, nblocks);
|
|
atomic_sub(nblocks, &transaction->t_outstanding_credits);
|
|
goto unlock;
|
|
}
|
|
|
|
if (wanted + (wanted >> JBD2_CONTROL_BLOCKS_SHIFT) >
|
|
jbd2_log_space_left(journal)) {
|
|
jbd_debug(3, "denied handle %p %d blocks: "
|
|
"insufficient log space\n", handle, nblocks);
|
|
atomic_sub(nblocks, &transaction->t_outstanding_credits);
|
|
goto unlock;
|
|
}
|
|
|
|
trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,
|
|
transaction->t_tid,
|
|
handle->h_type, handle->h_line_no,
|
|
handle->h_buffer_credits,
|
|
nblocks);
|
|
|
|
handle->h_buffer_credits += nblocks;
|
|
handle->h_requested_credits += nblocks;
|
|
result = 0;
|
|
|
|
jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
|
|
unlock:
|
|
spin_unlock(&transaction->t_handle_lock);
|
|
error_out:
|
|
read_unlock(&journal->j_state_lock);
|
|
return result;
|
|
}
|
|
|
|
|
|
/**
|
|
* int jbd2_journal_restart() - restart a handle .
|
|
* @handle: handle to restart
|
|
* @nblocks: nr credits requested
|
|
*
|
|
* Restart a handle for a multi-transaction filesystem
|
|
* operation.
|
|
*
|
|
* If the jbd2_journal_extend() call above fails to grant new buffer credits
|
|
* to a running handle, a call to jbd2_journal_restart will commit the
|
|
* handle's transaction so far and reattach the handle to a new
|
|
* transaction capabable of guaranteeing the requested number of
|
|
* credits. We preserve reserved handle if there's any attached to the
|
|
* passed in handle.
|
|
*/
|
|
int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
tid_t tid;
|
|
int need_to_start, ret;
|
|
|
|
/* If we've had an abort of any type, don't even think about
|
|
* actually doing the restart! */
|
|
if (is_handle_aborted(handle))
|
|
return 0;
|
|
journal = transaction->t_journal;
|
|
|
|
/*
|
|
* First unlink the handle from its current transaction, and start the
|
|
* commit on that.
|
|
*/
|
|
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
|
|
J_ASSERT(journal_current_handle() == handle);
|
|
|
|
read_lock(&journal->j_state_lock);
|
|
spin_lock(&transaction->t_handle_lock);
|
|
atomic_sub(handle->h_buffer_credits,
|
|
&transaction->t_outstanding_credits);
|
|
if (handle->h_rsv_handle) {
|
|
sub_reserved_credits(journal,
|
|
handle->h_rsv_handle->h_buffer_credits);
|
|
}
|
|
if (atomic_dec_and_test(&transaction->t_updates))
|
|
wake_up(&journal->j_wait_updates);
|
|
tid = transaction->t_tid;
|
|
spin_unlock(&transaction->t_handle_lock);
|
|
handle->h_transaction = NULL;
|
|
current->journal_info = NULL;
|
|
|
|
jbd_debug(2, "restarting handle %p\n", handle);
|
|
need_to_start = !tid_geq(journal->j_commit_request, tid);
|
|
read_unlock(&journal->j_state_lock);
|
|
if (need_to_start)
|
|
jbd2_log_start_commit(journal, tid);
|
|
|
|
lock_map_release(&handle->h_lockdep_map);
|
|
handle->h_buffer_credits = nblocks;
|
|
ret = start_this_handle(journal, handle, gfp_mask);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(jbd2__journal_restart);
|
|
|
|
|
|
int jbd2_journal_restart(handle_t *handle, int nblocks)
|
|
{
|
|
return jbd2__journal_restart(handle, nblocks, GFP_NOFS);
|
|
}
|
|
EXPORT_SYMBOL(jbd2_journal_restart);
|
|
|
|
/**
|
|
* void jbd2_journal_lock_updates () - establish a transaction barrier.
|
|
* @journal: Journal to establish a barrier on.
|
|
*
|
|
* This locks out any further updates from being started, and blocks
|
|
* until all existing updates have completed, returning only once the
|
|
* journal is in a quiescent state with no updates running.
|
|
*
|
|
* The journal lock should not be held on entry.
|
|
*/
|
|
void jbd2_journal_lock_updates(journal_t *journal)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
|
|
write_lock(&journal->j_state_lock);
|
|
++journal->j_barrier_count;
|
|
|
|
/* Wait until there are no reserved handles */
|
|
if (atomic_read(&journal->j_reserved_credits)) {
|
|
write_unlock(&journal->j_state_lock);
|
|
wait_event(journal->j_wait_reserved,
|
|
atomic_read(&journal->j_reserved_credits) == 0);
|
|
write_lock(&journal->j_state_lock);
|
|
}
|
|
|
|
/* Wait until there are no running updates */
|
|
while (1) {
|
|
transaction_t *transaction = journal->j_running_transaction;
|
|
|
|
if (!transaction)
|
|
break;
|
|
|
|
spin_lock(&transaction->t_handle_lock);
|
|
prepare_to_wait(&journal->j_wait_updates, &wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
if (!atomic_read(&transaction->t_updates)) {
|
|
spin_unlock(&transaction->t_handle_lock);
|
|
finish_wait(&journal->j_wait_updates, &wait);
|
|
break;
|
|
}
|
|
spin_unlock(&transaction->t_handle_lock);
|
|
write_unlock(&journal->j_state_lock);
|
|
schedule();
|
|
finish_wait(&journal->j_wait_updates, &wait);
|
|
write_lock(&journal->j_state_lock);
|
|
}
|
|
write_unlock(&journal->j_state_lock);
|
|
|
|
/*
|
|
* We have now established a barrier against other normal updates, but
|
|
* we also need to barrier against other jbd2_journal_lock_updates() calls
|
|
* to make sure that we serialise special journal-locked operations
|
|
* too.
|
|
*/
|
|
mutex_lock(&journal->j_barrier);
|
|
}
|
|
|
|
/**
|
|
* void jbd2_journal_unlock_updates (journal_t* journal) - release barrier
|
|
* @journal: Journal to release the barrier on.
|
|
*
|
|
* Release a transaction barrier obtained with jbd2_journal_lock_updates().
|
|
*
|
|
* Should be called without the journal lock held.
|
|
*/
|
|
void jbd2_journal_unlock_updates (journal_t *journal)
|
|
{
|
|
J_ASSERT(journal->j_barrier_count != 0);
|
|
|
|
mutex_unlock(&journal->j_barrier);
|
|
write_lock(&journal->j_state_lock);
|
|
--journal->j_barrier_count;
|
|
write_unlock(&journal->j_state_lock);
|
|
wake_up(&journal->j_wait_transaction_locked);
|
|
}
|
|
|
|
static void warn_dirty_buffer(struct buffer_head *bh)
|
|
{
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
printk(KERN_WARNING
|
|
"JBD2: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). "
|
|
"There's a risk of filesystem corruption in case of system "
|
|
"crash.\n",
|
|
bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
|
|
}
|
|
|
|
/*
|
|
* If the buffer is already part of the current transaction, then there
|
|
* is nothing we need to do. If it is already part of a prior
|
|
* transaction which we are still committing to disk, then we need to
|
|
* make sure that we do not overwrite the old copy: we do copy-out to
|
|
* preserve the copy going to disk. We also account the buffer against
|
|
* the handle's metadata buffer credits (unless the buffer is already
|
|
* part of the transaction, that is).
|
|
*
|
|
*/
|
|
static int
|
|
do_get_write_access(handle_t *handle, struct journal_head *jh,
|
|
int force_copy)
|
|
{
|
|
struct buffer_head *bh;
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
int error;
|
|
char *frozen_buffer = NULL;
|
|
int need_copy = 0;
|
|
unsigned long start_lock, time_lock;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EROFS;
|
|
journal = transaction->t_journal;
|
|
|
|
jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
|
|
|
|
JBUFFER_TRACE(jh, "entry");
|
|
repeat:
|
|
bh = jh2bh(jh);
|
|
|
|
/* @@@ Need to check for errors here at some point. */
|
|
|
|
start_lock = jiffies;
|
|
lock_buffer(bh);
|
|
jbd_lock_bh_state(bh);
|
|
|
|
/* If it takes too long to lock the buffer, trace it */
|
|
time_lock = jbd2_time_diff(start_lock, jiffies);
|
|
if (time_lock > HZ/10)
|
|
trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev,
|
|
jiffies_to_msecs(time_lock));
|
|
|
|
/* We now hold the buffer lock so it is safe to query the buffer
|
|
* state. Is the buffer dirty?
|
|
*
|
|
* If so, there are two possibilities. The buffer may be
|
|
* non-journaled, and undergoing a quite legitimate writeback.
|
|
* Otherwise, it is journaled, and we don't expect dirty buffers
|
|
* in that state (the buffers should be marked JBD_Dirty
|
|
* instead.) So either the IO is being done under our own
|
|
* control and this is a bug, or it's a third party IO such as
|
|
* dump(8) (which may leave the buffer scheduled for read ---
|
|
* ie. locked but not dirty) or tune2fs (which may actually have
|
|
* the buffer dirtied, ugh.) */
|
|
|
|
if (buffer_dirty(bh)) {
|
|
/*
|
|
* First question: is this buffer already part of the current
|
|
* transaction or the existing committing transaction?
|
|
*/
|
|
if (jh->b_transaction) {
|
|
J_ASSERT_JH(jh,
|
|
jh->b_transaction == transaction ||
|
|
jh->b_transaction ==
|
|
journal->j_committing_transaction);
|
|
if (jh->b_next_transaction)
|
|
J_ASSERT_JH(jh, jh->b_next_transaction ==
|
|
transaction);
|
|
warn_dirty_buffer(bh);
|
|
}
|
|
/*
|
|
* In any case we need to clean the dirty flag and we must
|
|
* do it under the buffer lock to be sure we don't race
|
|
* with running write-out.
|
|
*/
|
|
JBUFFER_TRACE(jh, "Journalling dirty buffer");
|
|
clear_buffer_dirty(bh);
|
|
set_buffer_jbddirty(bh);
|
|
}
|
|
|
|
unlock_buffer(bh);
|
|
|
|
error = -EROFS;
|
|
if (is_handle_aborted(handle)) {
|
|
jbd_unlock_bh_state(bh);
|
|
goto out;
|
|
}
|
|
error = 0;
|
|
|
|
/*
|
|
* The buffer is already part of this transaction if b_transaction or
|
|
* b_next_transaction points to it
|
|
*/
|
|
if (jh->b_transaction == transaction ||
|
|
jh->b_next_transaction == transaction)
|
|
goto done;
|
|
|
|
/*
|
|
* this is the first time this transaction is touching this buffer,
|
|
* reset the modified flag
|
|
*/
|
|
jh->b_modified = 0;
|
|
|
|
/*
|
|
* If there is already a copy-out version of this buffer, then we don't
|
|
* need to make another one
|
|
*/
|
|
if (jh->b_frozen_data) {
|
|
JBUFFER_TRACE(jh, "has frozen data");
|
|
J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
|
|
jh->b_next_transaction = transaction;
|
|
goto done;
|
|
}
|
|
|
|
/* Is there data here we need to preserve? */
|
|
|
|
if (jh->b_transaction && jh->b_transaction != transaction) {
|
|
JBUFFER_TRACE(jh, "owned by older transaction");
|
|
J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
|
|
J_ASSERT_JH(jh, jh->b_transaction ==
|
|
journal->j_committing_transaction);
|
|
|
|
/* There is one case we have to be very careful about.
|
|
* If the committing transaction is currently writing
|
|
* this buffer out to disk and has NOT made a copy-out,
|
|
* then we cannot modify the buffer contents at all
|
|
* right now. The essence of copy-out is that it is the
|
|
* extra copy, not the primary copy, which gets
|
|
* journaled. If the primary copy is already going to
|
|
* disk then we cannot do copy-out here. */
|
|
|
|
if (buffer_shadow(bh)) {
|
|
JBUFFER_TRACE(jh, "on shadow: sleep");
|
|
jbd_unlock_bh_state(bh);
|
|
wait_on_bit_io(&bh->b_state, BH_Shadow,
|
|
TASK_UNINTERRUPTIBLE);
|
|
goto repeat;
|
|
}
|
|
|
|
/*
|
|
* Only do the copy if the currently-owning transaction still
|
|
* needs it. If buffer isn't on BJ_Metadata list, the
|
|
* committing transaction is past that stage (here we use the
|
|
* fact that BH_Shadow is set under bh_state lock together with
|
|
* refiling to BJ_Shadow list and at this point we know the
|
|
* buffer doesn't have BH_Shadow set).
|
|
*
|
|
* Subtle point, though: if this is a get_undo_access,
|
|
* then we will be relying on the frozen_data to contain
|
|
* the new value of the committed_data record after the
|
|
* transaction, so we HAVE to force the frozen_data copy
|
|
* in that case.
|
|
*/
|
|
if (jh->b_jlist == BJ_Metadata || force_copy) {
|
|
JBUFFER_TRACE(jh, "generate frozen data");
|
|
if (!frozen_buffer) {
|
|
JBUFFER_TRACE(jh, "allocate memory for buffer");
|
|
jbd_unlock_bh_state(bh);
|
|
frozen_buffer =
|
|
jbd2_alloc(jh2bh(jh)->b_size,
|
|
GFP_NOFS);
|
|
if (!frozen_buffer) {
|
|
printk(KERN_ERR
|
|
"%s: OOM for frozen_buffer\n",
|
|
__func__);
|
|
JBUFFER_TRACE(jh, "oom!");
|
|
error = -ENOMEM;
|
|
jbd_lock_bh_state(bh);
|
|
goto done;
|
|
}
|
|
goto repeat;
|
|
}
|
|
jh->b_frozen_data = frozen_buffer;
|
|
frozen_buffer = NULL;
|
|
need_copy = 1;
|
|
}
|
|
jh->b_next_transaction = transaction;
|
|
}
|
|
|
|
|
|
/*
|
|
* Finally, if the buffer is not journaled right now, we need to make
|
|
* sure it doesn't get written to disk before the caller actually
|
|
* commits the new data
|
|
*/
|
|
if (!jh->b_transaction) {
|
|
JBUFFER_TRACE(jh, "no transaction");
|
|
J_ASSERT_JH(jh, !jh->b_next_transaction);
|
|
JBUFFER_TRACE(jh, "file as BJ_Reserved");
|
|
spin_lock(&journal->j_list_lock);
|
|
__jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
|
|
spin_unlock(&journal->j_list_lock);
|
|
}
|
|
|
|
done:
|
|
if (need_copy) {
|
|
struct page *page;
|
|
int offset;
|
|
char *source;
|
|
|
|
J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)),
|
|
"Possible IO failure.\n");
|
|
page = jh2bh(jh)->b_page;
|
|
offset = offset_in_page(jh2bh(jh)->b_data);
|
|
source = kmap_atomic(page);
|
|
/* Fire data frozen trigger just before we copy the data */
|
|
jbd2_buffer_frozen_trigger(jh, source + offset,
|
|
jh->b_triggers);
|
|
memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size);
|
|
kunmap_atomic(source);
|
|
|
|
/*
|
|
* Now that the frozen data is saved off, we need to store
|
|
* any matching triggers.
|
|
*/
|
|
jh->b_frozen_triggers = jh->b_triggers;
|
|
}
|
|
jbd_unlock_bh_state(bh);
|
|
|
|
/*
|
|
* If we are about to journal a buffer, then any revoke pending on it is
|
|
* no longer valid
|
|
*/
|
|
jbd2_journal_cancel_revoke(handle, jh);
|
|
|
|
out:
|
|
if (unlikely(frozen_buffer)) /* It's usually NULL */
|
|
jbd2_free(frozen_buffer, bh->b_size);
|
|
|
|
JBUFFER_TRACE(jh, "exit");
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
|
|
* @handle: transaction to add buffer modifications to
|
|
* @bh: bh to be used for metadata writes
|
|
*
|
|
* Returns an error code or 0 on success.
|
|
*
|
|
* In full data journalling mode the buffer may be of type BJ_AsyncData,
|
|
* because we're write()ing a buffer which is also part of a shared mapping.
|
|
*/
|
|
|
|
int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
struct journal_head *jh = jbd2_journal_add_journal_head(bh);
|
|
int rc;
|
|
|
|
/* We do not want to get caught playing with fields which the
|
|
* log thread also manipulates. Make sure that the buffer
|
|
* completes any outstanding IO before proceeding. */
|
|
rc = do_get_write_access(handle, jh, 0);
|
|
jbd2_journal_put_journal_head(jh);
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
* When the user wants to journal a newly created buffer_head
|
|
* (ie. getblk() returned a new buffer and we are going to populate it
|
|
* manually rather than reading off disk), then we need to keep the
|
|
* buffer_head locked until it has been completely filled with new
|
|
* data. In this case, we should be able to make the assertion that
|
|
* the bh is not already part of an existing transaction.
|
|
*
|
|
* The buffer should already be locked by the caller by this point.
|
|
* There is no lock ranking violation: it was a newly created,
|
|
* unlocked buffer beforehand. */
|
|
|
|
/**
|
|
* int jbd2_journal_get_create_access () - notify intent to use newly created bh
|
|
* @handle: transaction to new buffer to
|
|
* @bh: new buffer.
|
|
*
|
|
* Call this if you create a new bh.
|
|
*/
|
|
int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
struct journal_head *jh = jbd2_journal_add_journal_head(bh);
|
|
int err;
|
|
|
|
jbd_debug(5, "journal_head %p\n", jh);
|
|
err = -EROFS;
|
|
if (is_handle_aborted(handle))
|
|
goto out;
|
|
journal = transaction->t_journal;
|
|
err = 0;
|
|
|
|
JBUFFER_TRACE(jh, "entry");
|
|
/*
|
|
* The buffer may already belong to this transaction due to pre-zeroing
|
|
* in the filesystem's new_block code. It may also be on the previous,
|
|
* committing transaction's lists, but it HAS to be in Forget state in
|
|
* that case: the transaction must have deleted the buffer for it to be
|
|
* reused here.
|
|
*/
|
|
jbd_lock_bh_state(bh);
|
|
J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
|
|
jh->b_transaction == NULL ||
|
|
(jh->b_transaction == journal->j_committing_transaction &&
|
|
jh->b_jlist == BJ_Forget)));
|
|
|
|
J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
|
|
J_ASSERT_JH(jh, buffer_locked(jh2bh(jh)));
|
|
|
|
if (jh->b_transaction == NULL) {
|
|
/*
|
|
* Previous jbd2_journal_forget() could have left the buffer
|
|
* with jbddirty bit set because it was being committed. When
|
|
* the commit finished, we've filed the buffer for
|
|
* checkpointing and marked it dirty. Now we are reallocating
|
|
* the buffer so the transaction freeing it must have
|
|
* committed and so it's safe to clear the dirty bit.
|
|
*/
|
|
clear_buffer_dirty(jh2bh(jh));
|
|
/* first access by this transaction */
|
|
jh->b_modified = 0;
|
|
|
|
JBUFFER_TRACE(jh, "file as BJ_Reserved");
|
|
spin_lock(&journal->j_list_lock);
|
|
__jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
|
|
} else if (jh->b_transaction == journal->j_committing_transaction) {
|
|
/* first access by this transaction */
|
|
jh->b_modified = 0;
|
|
|
|
JBUFFER_TRACE(jh, "set next transaction");
|
|
spin_lock(&journal->j_list_lock);
|
|
jh->b_next_transaction = transaction;
|
|
}
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
|
|
/*
|
|
* akpm: I added this. ext3_alloc_branch can pick up new indirect
|
|
* blocks which contain freed but then revoked metadata. We need
|
|
* to cancel the revoke in case we end up freeing it yet again
|
|
* and the reallocating as data - this would cause a second revoke,
|
|
* which hits an assertion error.
|
|
*/
|
|
JBUFFER_TRACE(jh, "cancelling revoke");
|
|
jbd2_journal_cancel_revoke(handle, jh);
|
|
out:
|
|
jbd2_journal_put_journal_head(jh);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* int jbd2_journal_get_undo_access() - Notify intent to modify metadata with
|
|
* non-rewindable consequences
|
|
* @handle: transaction
|
|
* @bh: buffer to undo
|
|
*
|
|
* Sometimes there is a need to distinguish between metadata which has
|
|
* been committed to disk and that which has not. The ext3fs code uses
|
|
* this for freeing and allocating space, we have to make sure that we
|
|
* do not reuse freed space until the deallocation has been committed,
|
|
* since if we overwrote that space we would make the delete
|
|
* un-rewindable in case of a crash.
|
|
*
|
|
* To deal with that, jbd2_journal_get_undo_access requests write access to a
|
|
* buffer for parts of non-rewindable operations such as delete
|
|
* operations on the bitmaps. The journaling code must keep a copy of
|
|
* the buffer's contents prior to the undo_access call until such time
|
|
* as we know that the buffer has definitely been committed to disk.
|
|
*
|
|
* We never need to know which transaction the committed data is part
|
|
* of, buffers touched here are guaranteed to be dirtied later and so
|
|
* will be committed to a new transaction in due course, at which point
|
|
* we can discard the old committed data pointer.
|
|
*
|
|
* Returns error number or 0 on success.
|
|
*/
|
|
int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
int err;
|
|
struct journal_head *jh = jbd2_journal_add_journal_head(bh);
|
|
char *committed_data = NULL;
|
|
|
|
JBUFFER_TRACE(jh, "entry");
|
|
|
|
/*
|
|
* Do this first --- it can drop the journal lock, so we want to
|
|
* make sure that obtaining the committed_data is done
|
|
* atomically wrt. completion of any outstanding commits.
|
|
*/
|
|
err = do_get_write_access(handle, jh, 1);
|
|
if (err)
|
|
goto out;
|
|
|
|
repeat:
|
|
if (!jh->b_committed_data) {
|
|
committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS);
|
|
if (!committed_data) {
|
|
printk(KERN_ERR "%s: No memory for committed data\n",
|
|
__func__);
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
jbd_lock_bh_state(bh);
|
|
if (!jh->b_committed_data) {
|
|
/* Copy out the current buffer contents into the
|
|
* preserved, committed copy. */
|
|
JBUFFER_TRACE(jh, "generate b_committed data");
|
|
if (!committed_data) {
|
|
jbd_unlock_bh_state(bh);
|
|
goto repeat;
|
|
}
|
|
|
|
jh->b_committed_data = committed_data;
|
|
committed_data = NULL;
|
|
memcpy(jh->b_committed_data, bh->b_data, bh->b_size);
|
|
}
|
|
jbd_unlock_bh_state(bh);
|
|
out:
|
|
jbd2_journal_put_journal_head(jh);
|
|
if (unlikely(committed_data))
|
|
jbd2_free(committed_data, bh->b_size);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* void jbd2_journal_set_triggers() - Add triggers for commit writeout
|
|
* @bh: buffer to trigger on
|
|
* @type: struct jbd2_buffer_trigger_type containing the trigger(s).
|
|
*
|
|
* Set any triggers on this journal_head. This is always safe, because
|
|
* triggers for a committing buffer will be saved off, and triggers for
|
|
* a running transaction will match the buffer in that transaction.
|
|
*
|
|
* Call with NULL to clear the triggers.
|
|
*/
|
|
void jbd2_journal_set_triggers(struct buffer_head *bh,
|
|
struct jbd2_buffer_trigger_type *type)
|
|
{
|
|
struct journal_head *jh = jbd2_journal_grab_journal_head(bh);
|
|
|
|
if (WARN_ON(!jh))
|
|
return;
|
|
jh->b_triggers = type;
|
|
jbd2_journal_put_journal_head(jh);
|
|
}
|
|
|
|
void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data,
|
|
struct jbd2_buffer_trigger_type *triggers)
|
|
{
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
if (!triggers || !triggers->t_frozen)
|
|
return;
|
|
|
|
triggers->t_frozen(triggers, bh, mapped_data, bh->b_size);
|
|
}
|
|
|
|
void jbd2_buffer_abort_trigger(struct journal_head *jh,
|
|
struct jbd2_buffer_trigger_type *triggers)
|
|
{
|
|
if (!triggers || !triggers->t_abort)
|
|
return;
|
|
|
|
triggers->t_abort(triggers, jh2bh(jh));
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
* int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata
|
|
* @handle: transaction to add buffer to.
|
|
* @bh: buffer to mark
|
|
*
|
|
* mark dirty metadata which needs to be journaled as part of the current
|
|
* transaction.
|
|
*
|
|
* The buffer must have previously had jbd2_journal_get_write_access()
|
|
* called so that it has a valid journal_head attached to the buffer
|
|
* head.
|
|
*
|
|
* The buffer is placed on the transaction's metadata list and is marked
|
|
* as belonging to the transaction.
|
|
*
|
|
* Returns error number or 0 on success.
|
|
*
|
|
* Special care needs to be taken if the buffer already belongs to the
|
|
* current committing transaction (in which case we should have frozen
|
|
* data present for that commit). In that case, we don't relink the
|
|
* buffer: that only gets done when the old transaction finally
|
|
* completes its commit.
|
|
*/
|
|
int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
struct journal_head *jh;
|
|
int ret = 0;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EROFS;
|
|
journal = transaction->t_journal;
|
|
jh = jbd2_journal_grab_journal_head(bh);
|
|
if (!jh) {
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
jbd_debug(5, "journal_head %p\n", jh);
|
|
JBUFFER_TRACE(jh, "entry");
|
|
|
|
jbd_lock_bh_state(bh);
|
|
|
|
if (jh->b_modified == 0) {
|
|
/*
|
|
* This buffer's got modified and becoming part
|
|
* of the transaction. This needs to be done
|
|
* once a transaction -bzzz
|
|
*/
|
|
jh->b_modified = 1;
|
|
if (handle->h_buffer_credits <= 0) {
|
|
ret = -ENOSPC;
|
|
goto out_unlock_bh;
|
|
}
|
|
handle->h_buffer_credits--;
|
|
}
|
|
|
|
/*
|
|
* fastpath, to avoid expensive locking. If this buffer is already
|
|
* on the running transaction's metadata list there is nothing to do.
|
|
* Nobody can take it off again because there is a handle open.
|
|
* I _think_ we're OK here with SMP barriers - a mistaken decision will
|
|
* result in this test being false, so we go in and take the locks.
|
|
*/
|
|
if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) {
|
|
JBUFFER_TRACE(jh, "fastpath");
|
|
if (unlikely(jh->b_transaction !=
|
|
journal->j_running_transaction)) {
|
|
printk(KERN_ERR "JBD2: %s: "
|
|
"jh->b_transaction (%llu, %p, %u) != "
|
|
"journal->j_running_transaction (%p, %u)\n",
|
|
journal->j_devname,
|
|
(unsigned long long) bh->b_blocknr,
|
|
jh->b_transaction,
|
|
jh->b_transaction ? jh->b_transaction->t_tid : 0,
|
|
journal->j_running_transaction,
|
|
journal->j_running_transaction ?
|
|
journal->j_running_transaction->t_tid : 0);
|
|
ret = -EINVAL;
|
|
}
|
|
goto out_unlock_bh;
|
|
}
|
|
|
|
set_buffer_jbddirty(bh);
|
|
|
|
/*
|
|
* Metadata already on the current transaction list doesn't
|
|
* need to be filed. Metadata on another transaction's list must
|
|
* be committing, and will be refiled once the commit completes:
|
|
* leave it alone for now.
|
|
*/
|
|
if (jh->b_transaction != transaction) {
|
|
JBUFFER_TRACE(jh, "already on other transaction");
|
|
if (unlikely(((jh->b_transaction !=
|
|
journal->j_committing_transaction)) ||
|
|
(jh->b_next_transaction != transaction))) {
|
|
printk(KERN_ERR "jbd2_journal_dirty_metadata: %s: "
|
|
"bad jh for block %llu: "
|
|
"transaction (%p, %u), "
|
|
"jh->b_transaction (%p, %u), "
|
|
"jh->b_next_transaction (%p, %u), jlist %u\n",
|
|
journal->j_devname,
|
|
(unsigned long long) bh->b_blocknr,
|
|
transaction, transaction->t_tid,
|
|
jh->b_transaction,
|
|
jh->b_transaction ?
|
|
jh->b_transaction->t_tid : 0,
|
|
jh->b_next_transaction,
|
|
jh->b_next_transaction ?
|
|
jh->b_next_transaction->t_tid : 0,
|
|
jh->b_jlist);
|
|
WARN_ON(1);
|
|
ret = -EINVAL;
|
|
}
|
|
/* And this case is illegal: we can't reuse another
|
|
* transaction's data buffer, ever. */
|
|
goto out_unlock_bh;
|
|
}
|
|
|
|
/* That test should have eliminated the following case: */
|
|
J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
|
|
|
|
JBUFFER_TRACE(jh, "file as BJ_Metadata");
|
|
spin_lock(&journal->j_list_lock);
|
|
__jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
|
|
spin_unlock(&journal->j_list_lock);
|
|
out_unlock_bh:
|
|
jbd_unlock_bh_state(bh);
|
|
jbd2_journal_put_journal_head(jh);
|
|
out:
|
|
JBUFFER_TRACE(jh, "exit");
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* void jbd2_journal_forget() - bforget() for potentially-journaled buffers.
|
|
* @handle: transaction handle
|
|
* @bh: bh to 'forget'
|
|
*
|
|
* We can only do the bforget if there are no commits pending against the
|
|
* buffer. If the buffer is dirty in the current running transaction we
|
|
* can safely unlink it.
|
|
*
|
|
* bh may not be a journalled buffer at all - it may be a non-JBD
|
|
* buffer which came off the hashtable. Check for this.
|
|
*
|
|
* Decrements bh->b_count by one.
|
|
*
|
|
* Allow this call even if the handle has aborted --- it may be part of
|
|
* the caller's cleanup after an abort.
|
|
*/
|
|
int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
struct journal_head *jh;
|
|
int drop_reserve = 0;
|
|
int err = 0;
|
|
int was_modified = 0;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EROFS;
|
|
journal = transaction->t_journal;
|
|
|
|
BUFFER_TRACE(bh, "entry");
|
|
|
|
jbd_lock_bh_state(bh);
|
|
|
|
if (!buffer_jbd(bh))
|
|
goto not_jbd;
|
|
jh = bh2jh(bh);
|
|
|
|
/* Critical error: attempting to delete a bitmap buffer, maybe?
|
|
* Don't do any jbd operations, and return an error. */
|
|
if (!J_EXPECT_JH(jh, !jh->b_committed_data,
|
|
"inconsistent data on disk")) {
|
|
err = -EIO;
|
|
goto not_jbd;
|
|
}
|
|
|
|
/* keep track of whether or not this transaction modified us */
|
|
was_modified = jh->b_modified;
|
|
|
|
/*
|
|
* The buffer's going from the transaction, we must drop
|
|
* all references -bzzz
|
|
*/
|
|
jh->b_modified = 0;
|
|
|
|
if (jh->b_transaction == transaction) {
|
|
J_ASSERT_JH(jh, !jh->b_frozen_data);
|
|
|
|
/* If we are forgetting a buffer which is already part
|
|
* of this transaction, then we can just drop it from
|
|
* the transaction immediately. */
|
|
clear_buffer_dirty(bh);
|
|
clear_buffer_jbddirty(bh);
|
|
|
|
JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
|
|
|
|
/*
|
|
* we only want to drop a reference if this transaction
|
|
* modified the buffer
|
|
*/
|
|
if (was_modified)
|
|
drop_reserve = 1;
|
|
|
|
/*
|
|
* We are no longer going to journal this buffer.
|
|
* However, the commit of this transaction is still
|
|
* important to the buffer: the delete that we are now
|
|
* processing might obsolete an old log entry, so by
|
|
* committing, we can satisfy the buffer's checkpoint.
|
|
*
|
|
* So, if we have a checkpoint on the buffer, we should
|
|
* now refile the buffer on our BJ_Forget list so that
|
|
* we know to remove the checkpoint after we commit.
|
|
*/
|
|
|
|
spin_lock(&journal->j_list_lock);
|
|
if (jh->b_cp_transaction) {
|
|
__jbd2_journal_temp_unlink_buffer(jh);
|
|
__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
|
|
} else {
|
|
__jbd2_journal_unfile_buffer(jh);
|
|
if (!buffer_jbd(bh)) {
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
__bforget(bh);
|
|
goto drop;
|
|
}
|
|
}
|
|
spin_unlock(&journal->j_list_lock);
|
|
} else if (jh->b_transaction) {
|
|
J_ASSERT_JH(jh, (jh->b_transaction ==
|
|
journal->j_committing_transaction));
|
|
/* However, if the buffer is still owned by a prior
|
|
* (committing) transaction, we can't drop it yet... */
|
|
JBUFFER_TRACE(jh, "belongs to older transaction");
|
|
/* ... but we CAN drop it from the new transaction if we
|
|
* have also modified it since the original commit. */
|
|
|
|
if (jh->b_next_transaction) {
|
|
J_ASSERT(jh->b_next_transaction == transaction);
|
|
spin_lock(&journal->j_list_lock);
|
|
jh->b_next_transaction = NULL;
|
|
spin_unlock(&journal->j_list_lock);
|
|
|
|
/*
|
|
* only drop a reference if this transaction modified
|
|
* the buffer
|
|
*/
|
|
if (was_modified)
|
|
drop_reserve = 1;
|
|
}
|
|
}
|
|
|
|
not_jbd:
|
|
jbd_unlock_bh_state(bh);
|
|
__brelse(bh);
|
|
drop:
|
|
if (drop_reserve) {
|
|
/* no need to reserve log space for this block -bzzz */
|
|
handle->h_buffer_credits++;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* int jbd2_journal_stop() - complete a transaction
|
|
* @handle: tranaction to complete.
|
|
*
|
|
* All done for a particular handle.
|
|
*
|
|
* There is not much action needed here. We just return any remaining
|
|
* buffer credits to the transaction and remove the handle. The only
|
|
* complication is that we need to start a commit operation if the
|
|
* filesystem is marked for synchronous update.
|
|
*
|
|
* jbd2_journal_stop itself will not usually return an error, but it may
|
|
* do so in unusual circumstances. In particular, expect it to
|
|
* return -EIO if a jbd2_journal_abort has been executed since the
|
|
* transaction began.
|
|
*/
|
|
int jbd2_journal_stop(handle_t *handle)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
int err = 0, wait_for_commit = 0;
|
|
tid_t tid;
|
|
pid_t pid;
|
|
|
|
if (!transaction) {
|
|
/*
|
|
* Handle is already detached from the transaction so
|
|
* there is nothing to do other than decrease a refcount,
|
|
* or free the handle if refcount drops to zero
|
|
*/
|
|
if (--handle->h_ref > 0) {
|
|
jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
|
|
handle->h_ref);
|
|
return err;
|
|
} else {
|
|
if (handle->h_rsv_handle)
|
|
jbd2_free_handle(handle->h_rsv_handle);
|
|
goto free_and_exit;
|
|
}
|
|
}
|
|
journal = transaction->t_journal;
|
|
|
|
J_ASSERT(journal_current_handle() == handle);
|
|
|
|
if (is_handle_aborted(handle))
|
|
err = -EIO;
|
|
else
|
|
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
|
|
|
|
if (--handle->h_ref > 0) {
|
|
jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
|
|
handle->h_ref);
|
|
return err;
|
|
}
|
|
|
|
jbd_debug(4, "Handle %p going down\n", handle);
|
|
trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,
|
|
transaction->t_tid,
|
|
handle->h_type, handle->h_line_no,
|
|
jiffies - handle->h_start_jiffies,
|
|
handle->h_sync, handle->h_requested_credits,
|
|
(handle->h_requested_credits -
|
|
handle->h_buffer_credits));
|
|
|
|
/*
|
|
* Implement synchronous transaction batching. If the handle
|
|
* was synchronous, don't force a commit immediately. Let's
|
|
* yield and let another thread piggyback onto this
|
|
* transaction. Keep doing that while new threads continue to
|
|
* arrive. It doesn't cost much - we're about to run a commit
|
|
* and sleep on IO anyway. Speeds up many-threaded, many-dir
|
|
* operations by 30x or more...
|
|
*
|
|
* We try and optimize the sleep time against what the
|
|
* underlying disk can do, instead of having a static sleep
|
|
* time. This is useful for the case where our storage is so
|
|
* fast that it is more optimal to go ahead and force a flush
|
|
* and wait for the transaction to be committed than it is to
|
|
* wait for an arbitrary amount of time for new writers to
|
|
* join the transaction. We achieve this by measuring how
|
|
* long it takes to commit a transaction, and compare it with
|
|
* how long this transaction has been running, and if run time
|
|
* < commit time then we sleep for the delta and commit. This
|
|
* greatly helps super fast disks that would see slowdowns as
|
|
* more threads started doing fsyncs.
|
|
*
|
|
* But don't do this if this process was the most recent one
|
|
* to perform a synchronous write. We do this to detect the
|
|
* case where a single process is doing a stream of sync
|
|
* writes. No point in waiting for joiners in that case.
|
|
*
|
|
* Setting max_batch_time to 0 disables this completely.
|
|
*/
|
|
pid = current->pid;
|
|
if (handle->h_sync && journal->j_last_sync_writer != pid &&
|
|
journal->j_max_batch_time) {
|
|
u64 commit_time, trans_time;
|
|
|
|
journal->j_last_sync_writer = pid;
|
|
|
|
read_lock(&journal->j_state_lock);
|
|
commit_time = journal->j_average_commit_time;
|
|
read_unlock(&journal->j_state_lock);
|
|
|
|
trans_time = ktime_to_ns(ktime_sub(ktime_get(),
|
|
transaction->t_start_time));
|
|
|
|
commit_time = max_t(u64, commit_time,
|
|
1000*journal->j_min_batch_time);
|
|
commit_time = min_t(u64, commit_time,
|
|
1000*journal->j_max_batch_time);
|
|
|
|
if (trans_time < commit_time) {
|
|
ktime_t expires = ktime_add_ns(ktime_get(),
|
|
commit_time);
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
|
|
}
|
|
}
|
|
|
|
if (handle->h_sync)
|
|
transaction->t_synchronous_commit = 1;
|
|
current->journal_info = NULL;
|
|
atomic_sub(handle->h_buffer_credits,
|
|
&transaction->t_outstanding_credits);
|
|
|
|
/*
|
|
* If the handle is marked SYNC, we need to set another commit
|
|
* going! We also want to force a commit if the current
|
|
* transaction is occupying too much of the log, or if the
|
|
* transaction is too old now.
|
|
*/
|
|
if (handle->h_sync ||
|
|
(atomic_read(&transaction->t_outstanding_credits) >
|
|
journal->j_max_transaction_buffers) ||
|
|
time_after_eq(jiffies, transaction->t_expires)) {
|
|
/* Do this even for aborted journals: an abort still
|
|
* completes the commit thread, it just doesn't write
|
|
* anything to disk. */
|
|
|
|
jbd_debug(2, "transaction too old, requesting commit for "
|
|
"handle %p\n", handle);
|
|
/* This is non-blocking */
|
|
jbd2_log_start_commit(journal, transaction->t_tid);
|
|
|
|
/*
|
|
* Special case: JBD2_SYNC synchronous updates require us
|
|
* to wait for the commit to complete.
|
|
*/
|
|
if (handle->h_sync && !(current->flags & PF_MEMALLOC))
|
|
wait_for_commit = 1;
|
|
}
|
|
|
|
/*
|
|
* Once we drop t_updates, if it goes to zero the transaction
|
|
* could start committing on us and eventually disappear. So
|
|
* once we do this, we must not dereference transaction
|
|
* pointer again.
|
|
*/
|
|
tid = transaction->t_tid;
|
|
if (atomic_dec_and_test(&transaction->t_updates)) {
|
|
wake_up(&journal->j_wait_updates);
|
|
if (journal->j_barrier_count)
|
|
wake_up(&journal->j_wait_transaction_locked);
|
|
}
|
|
|
|
if (wait_for_commit)
|
|
err = jbd2_log_wait_commit(journal, tid);
|
|
|
|
lock_map_release(&handle->h_lockdep_map);
|
|
|
|
if (handle->h_rsv_handle)
|
|
jbd2_journal_free_reserved(handle->h_rsv_handle);
|
|
free_and_exit:
|
|
jbd2_free_handle(handle);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
*
|
|
* List management code snippets: various functions for manipulating the
|
|
* transaction buffer lists.
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* Append a buffer to a transaction list, given the transaction's list head
|
|
* pointer.
|
|
*
|
|
* j_list_lock is held.
|
|
*
|
|
* jbd_lock_bh_state(jh2bh(jh)) is held.
|
|
*/
|
|
|
|
static inline void
|
|
__blist_add_buffer(struct journal_head **list, struct journal_head *jh)
|
|
{
|
|
if (!*list) {
|
|
jh->b_tnext = jh->b_tprev = jh;
|
|
*list = jh;
|
|
} else {
|
|
/* Insert at the tail of the list to preserve order */
|
|
struct journal_head *first = *list, *last = first->b_tprev;
|
|
jh->b_tprev = last;
|
|
jh->b_tnext = first;
|
|
last->b_tnext = first->b_tprev = jh;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove a buffer from a transaction list, given the transaction's list
|
|
* head pointer.
|
|
*
|
|
* Called with j_list_lock held, and the journal may not be locked.
|
|
*
|
|
* jbd_lock_bh_state(jh2bh(jh)) is held.
|
|
*/
|
|
|
|
static inline void
|
|
__blist_del_buffer(struct journal_head **list, struct journal_head *jh)
|
|
{
|
|
if (*list == jh) {
|
|
*list = jh->b_tnext;
|
|
if (*list == jh)
|
|
*list = NULL;
|
|
}
|
|
jh->b_tprev->b_tnext = jh->b_tnext;
|
|
jh->b_tnext->b_tprev = jh->b_tprev;
|
|
}
|
|
|
|
/*
|
|
* Remove a buffer from the appropriate transaction list.
|
|
*
|
|
* Note that this function can *change* the value of
|
|
* bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or
|
|
* t_reserved_list. If the caller is holding onto a copy of one of these
|
|
* pointers, it could go bad. Generally the caller needs to re-read the
|
|
* pointer from the transaction_t.
|
|
*
|
|
* Called under j_list_lock.
|
|
*/
|
|
static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
|
|
{
|
|
struct journal_head **list = NULL;
|
|
transaction_t *transaction;
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
|
|
transaction = jh->b_transaction;
|
|
if (transaction)
|
|
assert_spin_locked(&transaction->t_journal->j_list_lock);
|
|
|
|
J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
|
|
if (jh->b_jlist != BJ_None)
|
|
J_ASSERT_JH(jh, transaction != NULL);
|
|
|
|
switch (jh->b_jlist) {
|
|
case BJ_None:
|
|
return;
|
|
case BJ_Metadata:
|
|
transaction->t_nr_buffers--;
|
|
J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0);
|
|
list = &transaction->t_buffers;
|
|
break;
|
|
case BJ_Forget:
|
|
list = &transaction->t_forget;
|
|
break;
|
|
case BJ_Shadow:
|
|
list = &transaction->t_shadow_list;
|
|
break;
|
|
case BJ_Reserved:
|
|
list = &transaction->t_reserved_list;
|
|
break;
|
|
}
|
|
|
|
__blist_del_buffer(list, jh);
|
|
jh->b_jlist = BJ_None;
|
|
if (test_clear_buffer_jbddirty(bh))
|
|
mark_buffer_dirty(bh); /* Expose it to the VM */
|
|
}
|
|
|
|
/*
|
|
* Remove buffer from all transactions.
|
|
*
|
|
* Called with bh_state lock and j_list_lock
|
|
*
|
|
* jh and bh may be already freed when this function returns.
|
|
*/
|
|
static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
|
|
{
|
|
__jbd2_journal_temp_unlink_buffer(jh);
|
|
jh->b_transaction = NULL;
|
|
jbd2_journal_put_journal_head(jh);
|
|
}
|
|
|
|
void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
|
|
{
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
/* Get reference so that buffer cannot be freed before we unlock it */
|
|
get_bh(bh);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
__jbd2_journal_unfile_buffer(jh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
__brelse(bh);
|
|
}
|
|
|
|
/*
|
|
* Called from jbd2_journal_try_to_free_buffers().
|
|
*
|
|
* Called under jbd_lock_bh_state(bh)
|
|
*/
|
|
static void
|
|
__journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
|
|
{
|
|
struct journal_head *jh;
|
|
|
|
jh = bh2jh(bh);
|
|
|
|
if (buffer_locked(bh) || buffer_dirty(bh))
|
|
goto out;
|
|
|
|
if (jh->b_next_transaction != NULL || jh->b_transaction != NULL)
|
|
goto out;
|
|
|
|
spin_lock(&journal->j_list_lock);
|
|
if (jh->b_cp_transaction != NULL) {
|
|
/* written-back checkpointed metadata buffer */
|
|
JBUFFER_TRACE(jh, "remove from checkpoint list");
|
|
__jbd2_journal_remove_checkpoint(jh);
|
|
}
|
|
spin_unlock(&journal->j_list_lock);
|
|
out:
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* int jbd2_journal_try_to_free_buffers() - try to free page buffers.
|
|
* @journal: journal for operation
|
|
* @page: to try and free
|
|
* @gfp_mask: we use the mask to detect how hard should we try to release
|
|
* buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to
|
|
* release the buffers.
|
|
*
|
|
*
|
|
* For all the buffers on this page,
|
|
* if they are fully written out ordered data, move them onto BUF_CLEAN
|
|
* so try_to_free_buffers() can reap them.
|
|
*
|
|
* This function returns non-zero if we wish try_to_free_buffers()
|
|
* to be called. We do this if the page is releasable by try_to_free_buffers().
|
|
* We also do it if the page has locked or dirty buffers and the caller wants
|
|
* us to perform sync or async writeout.
|
|
*
|
|
* This complicates JBD locking somewhat. We aren't protected by the
|
|
* BKL here. We wish to remove the buffer from its committing or
|
|
* running transaction's ->t_datalist via __jbd2_journal_unfile_buffer.
|
|
*
|
|
* This may *change* the value of transaction_t->t_datalist, so anyone
|
|
* who looks at t_datalist needs to lock against this function.
|
|
*
|
|
* Even worse, someone may be doing a jbd2_journal_dirty_data on this
|
|
* buffer. So we need to lock against that. jbd2_journal_dirty_data()
|
|
* will come out of the lock with the buffer dirty, which makes it
|
|
* ineligible for release here.
|
|
*
|
|
* Who else is affected by this? hmm... Really the only contender
|
|
* is do_get_write_access() - it could be looking at the buffer while
|
|
* journal_try_to_free_buffer() is changing its state. But that
|
|
* cannot happen because we never reallocate freed data as metadata
|
|
* while the data is part of a transaction. Yes?
|
|
*
|
|
* Return 0 on failure, 1 on success
|
|
*/
|
|
int jbd2_journal_try_to_free_buffers(journal_t *journal,
|
|
struct page *page, gfp_t gfp_mask)
|
|
{
|
|
struct buffer_head *head;
|
|
struct buffer_head *bh;
|
|
int ret = 0;
|
|
|
|
J_ASSERT(PageLocked(page));
|
|
|
|
head = page_buffers(page);
|
|
bh = head;
|
|
do {
|
|
struct journal_head *jh;
|
|
|
|
/*
|
|
* We take our own ref against the journal_head here to avoid
|
|
* having to add tons of locking around each instance of
|
|
* jbd2_journal_put_journal_head().
|
|
*/
|
|
jh = jbd2_journal_grab_journal_head(bh);
|
|
if (!jh)
|
|
continue;
|
|
|
|
jbd_lock_bh_state(bh);
|
|
__journal_try_to_free_buffer(journal, bh);
|
|
jbd2_journal_put_journal_head(jh);
|
|
jbd_unlock_bh_state(bh);
|
|
if (buffer_jbd(bh))
|
|
goto busy;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
|
|
ret = try_to_free_buffers(page);
|
|
|
|
busy:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This buffer is no longer needed. If it is on an older transaction's
|
|
* checkpoint list we need to record it on this transaction's forget list
|
|
* to pin this buffer (and hence its checkpointing transaction) down until
|
|
* this transaction commits. If the buffer isn't on a checkpoint list, we
|
|
* release it.
|
|
* Returns non-zero if JBD no longer has an interest in the buffer.
|
|
*
|
|
* Called under j_list_lock.
|
|
*
|
|
* Called under jbd_lock_bh_state(bh).
|
|
*/
|
|
static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction)
|
|
{
|
|
int may_free = 1;
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
if (jh->b_cp_transaction) {
|
|
JBUFFER_TRACE(jh, "on running+cp transaction");
|
|
__jbd2_journal_temp_unlink_buffer(jh);
|
|
/*
|
|
* We don't want to write the buffer anymore, clear the
|
|
* bit so that we don't confuse checks in
|
|
* __journal_file_buffer
|
|
*/
|
|
clear_buffer_dirty(bh);
|
|
__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
|
|
may_free = 0;
|
|
} else {
|
|
JBUFFER_TRACE(jh, "on running transaction");
|
|
__jbd2_journal_unfile_buffer(jh);
|
|
}
|
|
return may_free;
|
|
}
|
|
|
|
/*
|
|
* jbd2_journal_invalidatepage
|
|
*
|
|
* This code is tricky. It has a number of cases to deal with.
|
|
*
|
|
* There are two invariants which this code relies on:
|
|
*
|
|
* i_size must be updated on disk before we start calling invalidatepage on the
|
|
* data.
|
|
*
|
|
* This is done in ext3 by defining an ext3_setattr method which
|
|
* updates i_size before truncate gets going. By maintaining this
|
|
* invariant, we can be sure that it is safe to throw away any buffers
|
|
* attached to the current transaction: once the transaction commits,
|
|
* we know that the data will not be needed.
|
|
*
|
|
* Note however that we can *not* throw away data belonging to the
|
|
* previous, committing transaction!
|
|
*
|
|
* Any disk blocks which *are* part of the previous, committing
|
|
* transaction (and which therefore cannot be discarded immediately) are
|
|
* not going to be reused in the new running transaction
|
|
*
|
|
* The bitmap committed_data images guarantee this: any block which is
|
|
* allocated in one transaction and removed in the next will be marked
|
|
* as in-use in the committed_data bitmap, so cannot be reused until
|
|
* the next transaction to delete the block commits. This means that
|
|
* leaving committing buffers dirty is quite safe: the disk blocks
|
|
* cannot be reallocated to a different file and so buffer aliasing is
|
|
* not possible.
|
|
*
|
|
*
|
|
* The above applies mainly to ordered data mode. In writeback mode we
|
|
* don't make guarantees about the order in which data hits disk --- in
|
|
* particular we don't guarantee that new dirty data is flushed before
|
|
* transaction commit --- so it is always safe just to discard data
|
|
* immediately in that mode. --sct
|
|
*/
|
|
|
|
/*
|
|
* The journal_unmap_buffer helper function returns zero if the buffer
|
|
* concerned remains pinned as an anonymous buffer belonging to an older
|
|
* transaction.
|
|
*
|
|
* We're outside-transaction here. Either or both of j_running_transaction
|
|
* and j_committing_transaction may be NULL.
|
|
*/
|
|
static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
|
|
int partial_page)
|
|
{
|
|
transaction_t *transaction;
|
|
struct journal_head *jh;
|
|
int may_free = 1;
|
|
|
|
BUFFER_TRACE(bh, "entry");
|
|
|
|
/*
|
|
* It is safe to proceed here without the j_list_lock because the
|
|
* buffers cannot be stolen by try_to_free_buffers as long as we are
|
|
* holding the page lock. --sct
|
|
*/
|
|
|
|
if (!buffer_jbd(bh))
|
|
goto zap_buffer_unlocked;
|
|
|
|
/* OK, we have data buffer in journaled mode */
|
|
write_lock(&journal->j_state_lock);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
|
|
jh = jbd2_journal_grab_journal_head(bh);
|
|
if (!jh)
|
|
goto zap_buffer_no_jh;
|
|
|
|
/*
|
|
* We cannot remove the buffer from checkpoint lists until the
|
|
* transaction adding inode to orphan list (let's call it T)
|
|
* is committed. Otherwise if the transaction changing the
|
|
* buffer would be cleaned from the journal before T is
|
|
* committed, a crash will cause that the correct contents of
|
|
* the buffer will be lost. On the other hand we have to
|
|
* clear the buffer dirty bit at latest at the moment when the
|
|
* transaction marking the buffer as freed in the filesystem
|
|
* structures is committed because from that moment on the
|
|
* block can be reallocated and used by a different page.
|
|
* Since the block hasn't been freed yet but the inode has
|
|
* already been added to orphan list, it is safe for us to add
|
|
* the buffer to BJ_Forget list of the newest transaction.
|
|
*
|
|
* Also we have to clear buffer_mapped flag of a truncated buffer
|
|
* because the buffer_head may be attached to the page straddling
|
|
* i_size (can happen only when blocksize < pagesize) and thus the
|
|
* buffer_head can be reused when the file is extended again. So we end
|
|
* up keeping around invalidated buffers attached to transactions'
|
|
* BJ_Forget list just to stop checkpointing code from cleaning up
|
|
* the transaction this buffer was modified in.
|
|
*/
|
|
transaction = jh->b_transaction;
|
|
if (transaction == NULL) {
|
|
/* First case: not on any transaction. If it
|
|
* has no checkpoint link, then we can zap it:
|
|
* it's a writeback-mode buffer so we don't care
|
|
* if it hits disk safely. */
|
|
if (!jh->b_cp_transaction) {
|
|
JBUFFER_TRACE(jh, "not on any transaction: zap");
|
|
goto zap_buffer;
|
|
}
|
|
|
|
if (!buffer_dirty(bh)) {
|
|
/* bdflush has written it. We can drop it now */
|
|
goto zap_buffer;
|
|
}
|
|
|
|
/* OK, it must be in the journal but still not
|
|
* written fully to disk: it's metadata or
|
|
* journaled data... */
|
|
|
|
if (journal->j_running_transaction) {
|
|
/* ... and once the current transaction has
|
|
* committed, the buffer won't be needed any
|
|
* longer. */
|
|
JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget");
|
|
may_free = __dispose_buffer(jh,
|
|
journal->j_running_transaction);
|
|
goto zap_buffer;
|
|
} else {
|
|
/* There is no currently-running transaction. So the
|
|
* orphan record which we wrote for this file must have
|
|
* passed into commit. We must attach this buffer to
|
|
* the committing transaction, if it exists. */
|
|
if (journal->j_committing_transaction) {
|
|
JBUFFER_TRACE(jh, "give to committing trans");
|
|
may_free = __dispose_buffer(jh,
|
|
journal->j_committing_transaction);
|
|
goto zap_buffer;
|
|
} else {
|
|
/* The orphan record's transaction has
|
|
* committed. We can cleanse this buffer */
|
|
clear_buffer_jbddirty(bh);
|
|
goto zap_buffer;
|
|
}
|
|
}
|
|
} else if (transaction == journal->j_committing_transaction) {
|
|
JBUFFER_TRACE(jh, "on committing transaction");
|
|
/*
|
|
* The buffer is committing, we simply cannot touch
|
|
* it. If the page is straddling i_size we have to wait
|
|
* for commit and try again.
|
|
*/
|
|
if (partial_page) {
|
|
jbd2_journal_put_journal_head(jh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
write_unlock(&journal->j_state_lock);
|
|
return -EBUSY;
|
|
}
|
|
/*
|
|
* OK, buffer won't be reachable after truncate. We just set
|
|
* j_next_transaction to the running transaction (if there is
|
|
* one) and mark buffer as freed so that commit code knows it
|
|
* should clear dirty bits when it is done with the buffer.
|
|
*/
|
|
set_buffer_freed(bh);
|
|
if (journal->j_running_transaction && buffer_jbddirty(bh))
|
|
jh->b_next_transaction = journal->j_running_transaction;
|
|
jbd2_journal_put_journal_head(jh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
write_unlock(&journal->j_state_lock);
|
|
return 0;
|
|
} else {
|
|
/* Good, the buffer belongs to the running transaction.
|
|
* We are writing our own transaction's data, not any
|
|
* previous one's, so it is safe to throw it away
|
|
* (remember that we expect the filesystem to have set
|
|
* i_size already for this truncate so recovery will not
|
|
* expose the disk blocks we are discarding here.) */
|
|
J_ASSERT_JH(jh, transaction == journal->j_running_transaction);
|
|
JBUFFER_TRACE(jh, "on running transaction");
|
|
may_free = __dispose_buffer(jh, transaction);
|
|
}
|
|
|
|
zap_buffer:
|
|
/*
|
|
* This is tricky. Although the buffer is truncated, it may be reused
|
|
* if blocksize < pagesize and it is attached to the page straddling
|
|
* EOF. Since the buffer might have been added to BJ_Forget list of the
|
|
* running transaction, journal_get_write_access() won't clear
|
|
* b_modified and credit accounting gets confused. So clear b_modified
|
|
* here.
|
|
*/
|
|
jh->b_modified = 0;
|
|
jbd2_journal_put_journal_head(jh);
|
|
zap_buffer_no_jh:
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
write_unlock(&journal->j_state_lock);
|
|
zap_buffer_unlocked:
|
|
clear_buffer_dirty(bh);
|
|
J_ASSERT_BH(bh, !buffer_jbddirty(bh));
|
|
clear_buffer_mapped(bh);
|
|
clear_buffer_req(bh);
|
|
clear_buffer_new(bh);
|
|
clear_buffer_delay(bh);
|
|
clear_buffer_unwritten(bh);
|
|
bh->b_bdev = NULL;
|
|
return may_free;
|
|
}
|
|
|
|
/**
|
|
* void jbd2_journal_invalidatepage()
|
|
* @journal: journal to use for flush...
|
|
* @page: page to flush
|
|
* @offset: start of the range to invalidate
|
|
* @length: length of the range to invalidate
|
|
*
|
|
* Reap page buffers containing data after in the specified range in page.
|
|
* Can return -EBUSY if buffers are part of the committing transaction and
|
|
* the page is straddling i_size. Caller then has to wait for current commit
|
|
* and try again.
|
|
*/
|
|
int jbd2_journal_invalidatepage(journal_t *journal,
|
|
struct page *page,
|
|
unsigned int offset,
|
|
unsigned int length)
|
|
{
|
|
struct buffer_head *head, *bh, *next;
|
|
unsigned int stop = offset + length;
|
|
unsigned int curr_off = 0;
|
|
int partial_page = (offset || length < PAGE_CACHE_SIZE);
|
|
int may_free = 1;
|
|
int ret = 0;
|
|
|
|
if (!PageLocked(page))
|
|
BUG();
|
|
if (!page_has_buffers(page))
|
|
return 0;
|
|
|
|
BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
|
|
|
|
/* We will potentially be playing with lists other than just the
|
|
* data lists (especially for journaled data mode), so be
|
|
* cautious in our locking. */
|
|
|
|
head = bh = page_buffers(page);
|
|
do {
|
|
unsigned int next_off = curr_off + bh->b_size;
|
|
next = bh->b_this_page;
|
|
|
|
if (next_off > stop)
|
|
return 0;
|
|
|
|
if (offset <= curr_off) {
|
|
/* This block is wholly outside the truncation point */
|
|
lock_buffer(bh);
|
|
ret = journal_unmap_buffer(journal, bh, partial_page);
|
|
unlock_buffer(bh);
|
|
if (ret < 0)
|
|
return ret;
|
|
may_free &= ret;
|
|
}
|
|
curr_off = next_off;
|
|
bh = next;
|
|
|
|
} while (bh != head);
|
|
|
|
if (!partial_page) {
|
|
if (may_free && try_to_free_buffers(page))
|
|
J_ASSERT(!page_has_buffers(page));
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* File a buffer on the given transaction list.
|
|
*/
|
|
void __jbd2_journal_file_buffer(struct journal_head *jh,
|
|
transaction_t *transaction, int jlist)
|
|
{
|
|
struct journal_head **list = NULL;
|
|
int was_dirty = 0;
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
|
|
assert_spin_locked(&transaction->t_journal->j_list_lock);
|
|
|
|
J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
|
|
J_ASSERT_JH(jh, jh->b_transaction == transaction ||
|
|
jh->b_transaction == NULL);
|
|
|
|
if (jh->b_transaction && jh->b_jlist == jlist)
|
|
return;
|
|
|
|
if (jlist == BJ_Metadata || jlist == BJ_Reserved ||
|
|
jlist == BJ_Shadow || jlist == BJ_Forget) {
|
|
/*
|
|
* For metadata buffers, we track dirty bit in buffer_jbddirty
|
|
* instead of buffer_dirty. We should not see a dirty bit set
|
|
* here because we clear it in do_get_write_access but e.g.
|
|
* tune2fs can modify the sb and set the dirty bit at any time
|
|
* so we try to gracefully handle that.
|
|
*/
|
|
if (buffer_dirty(bh))
|
|
warn_dirty_buffer(bh);
|
|
if (test_clear_buffer_dirty(bh) ||
|
|
test_clear_buffer_jbddirty(bh))
|
|
was_dirty = 1;
|
|
}
|
|
|
|
if (jh->b_transaction)
|
|
__jbd2_journal_temp_unlink_buffer(jh);
|
|
else
|
|
jbd2_journal_grab_journal_head(bh);
|
|
jh->b_transaction = transaction;
|
|
|
|
switch (jlist) {
|
|
case BJ_None:
|
|
J_ASSERT_JH(jh, !jh->b_committed_data);
|
|
J_ASSERT_JH(jh, !jh->b_frozen_data);
|
|
return;
|
|
case BJ_Metadata:
|
|
transaction->t_nr_buffers++;
|
|
list = &transaction->t_buffers;
|
|
break;
|
|
case BJ_Forget:
|
|
list = &transaction->t_forget;
|
|
break;
|
|
case BJ_Shadow:
|
|
list = &transaction->t_shadow_list;
|
|
break;
|
|
case BJ_Reserved:
|
|
list = &transaction->t_reserved_list;
|
|
break;
|
|
}
|
|
|
|
__blist_add_buffer(list, jh);
|
|
jh->b_jlist = jlist;
|
|
|
|
if (was_dirty)
|
|
set_buffer_jbddirty(bh);
|
|
}
|
|
|
|
void jbd2_journal_file_buffer(struct journal_head *jh,
|
|
transaction_t *transaction, int jlist)
|
|
{
|
|
jbd_lock_bh_state(jh2bh(jh));
|
|
spin_lock(&transaction->t_journal->j_list_lock);
|
|
__jbd2_journal_file_buffer(jh, transaction, jlist);
|
|
spin_unlock(&transaction->t_journal->j_list_lock);
|
|
jbd_unlock_bh_state(jh2bh(jh));
|
|
}
|
|
|
|
/*
|
|
* Remove a buffer from its current buffer list in preparation for
|
|
* dropping it from its current transaction entirely. If the buffer has
|
|
* already started to be used by a subsequent transaction, refile the
|
|
* buffer on that transaction's metadata list.
|
|
*
|
|
* Called under j_list_lock
|
|
* Called under jbd_lock_bh_state(jh2bh(jh))
|
|
*
|
|
* jh and bh may be already free when this function returns
|
|
*/
|
|
void __jbd2_journal_refile_buffer(struct journal_head *jh)
|
|
{
|
|
int was_dirty, jlist;
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
|
|
if (jh->b_transaction)
|
|
assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
|
|
|
|
/* If the buffer is now unused, just drop it. */
|
|
if (jh->b_next_transaction == NULL) {
|
|
__jbd2_journal_unfile_buffer(jh);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* It has been modified by a later transaction: add it to the new
|
|
* transaction's metadata list.
|
|
*/
|
|
|
|
was_dirty = test_clear_buffer_jbddirty(bh);
|
|
__jbd2_journal_temp_unlink_buffer(jh);
|
|
/*
|
|
* We set b_transaction here because b_next_transaction will inherit
|
|
* our jh reference and thus __jbd2_journal_file_buffer() must not
|
|
* take a new one.
|
|
*/
|
|
jh->b_transaction = jh->b_next_transaction;
|
|
jh->b_next_transaction = NULL;
|
|
if (buffer_freed(bh))
|
|
jlist = BJ_Forget;
|
|
else if (jh->b_modified)
|
|
jlist = BJ_Metadata;
|
|
else
|
|
jlist = BJ_Reserved;
|
|
__jbd2_journal_file_buffer(jh, jh->b_transaction, jlist);
|
|
J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
|
|
|
|
if (was_dirty)
|
|
set_buffer_jbddirty(bh);
|
|
}
|
|
|
|
/*
|
|
* __jbd2_journal_refile_buffer() with necessary locking added. We take our
|
|
* bh reference so that we can safely unlock bh.
|
|
*
|
|
* The jh and bh may be freed by this call.
|
|
*/
|
|
void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
|
|
{
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
/* Get reference so that buffer cannot be freed before we unlock it */
|
|
get_bh(bh);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
__jbd2_journal_refile_buffer(jh);
|
|
jbd_unlock_bh_state(bh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
__brelse(bh);
|
|
}
|
|
|
|
/*
|
|
* File inode in the inode list of the handle's transaction
|
|
*/
|
|
int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EROFS;
|
|
journal = transaction->t_journal;
|
|
|
|
jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
|
|
transaction->t_tid);
|
|
|
|
/*
|
|
* First check whether inode isn't already on the transaction's
|
|
* lists without taking the lock. Note that this check is safe
|
|
* without the lock as we cannot race with somebody removing inode
|
|
* from the transaction. The reason is that we remove inode from the
|
|
* transaction only in journal_release_jbd_inode() and when we commit
|
|
* the transaction. We are guarded from the first case by holding
|
|
* a reference to the inode. We are safe against the second case
|
|
* because if jinode->i_transaction == transaction, commit code
|
|
* cannot touch the transaction because we hold reference to it,
|
|
* and if jinode->i_next_transaction == transaction, commit code
|
|
* will only file the inode where we want it.
|
|
*/
|
|
if (jinode->i_transaction == transaction ||
|
|
jinode->i_next_transaction == transaction)
|
|
return 0;
|
|
|
|
spin_lock(&journal->j_list_lock);
|
|
|
|
if (jinode->i_transaction == transaction ||
|
|
jinode->i_next_transaction == transaction)
|
|
goto done;
|
|
|
|
/*
|
|
* We only ever set this variable to 1 so the test is safe. Since
|
|
* t_need_data_flush is likely to be set, we do the test to save some
|
|
* cacheline bouncing
|
|
*/
|
|
if (!transaction->t_need_data_flush)
|
|
transaction->t_need_data_flush = 1;
|
|
/* On some different transaction's list - should be
|
|
* the committing one */
|
|
if (jinode->i_transaction) {
|
|
J_ASSERT(jinode->i_next_transaction == NULL);
|
|
J_ASSERT(jinode->i_transaction ==
|
|
journal->j_committing_transaction);
|
|
jinode->i_next_transaction = transaction;
|
|
goto done;
|
|
}
|
|
/* Not on any transaction list... */
|
|
J_ASSERT(!jinode->i_next_transaction);
|
|
jinode->i_transaction = transaction;
|
|
list_add(&jinode->i_list, &transaction->t_inode_list);
|
|
done:
|
|
spin_unlock(&journal->j_list_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* File truncate and transaction commit interact with each other in a
|
|
* non-trivial way. If a transaction writing data block A is
|
|
* committing, we cannot discard the data by truncate until we have
|
|
* written them. Otherwise if we crashed after the transaction with
|
|
* write has committed but before the transaction with truncate has
|
|
* committed, we could see stale data in block A. This function is a
|
|
* helper to solve this problem. It starts writeout of the truncated
|
|
* part in case it is in the committing transaction.
|
|
*
|
|
* Filesystem code must call this function when inode is journaled in
|
|
* ordered mode before truncation happens and after the inode has been
|
|
* placed on orphan list with the new inode size. The second condition
|
|
* avoids the race that someone writes new data and we start
|
|
* committing the transaction after this function has been called but
|
|
* before a transaction for truncate is started (and furthermore it
|
|
* allows us to optimize the case where the addition to orphan list
|
|
* happens in the same transaction as write --- we don't have to write
|
|
* any data in such case).
|
|
*/
|
|
int jbd2_journal_begin_ordered_truncate(journal_t *journal,
|
|
struct jbd2_inode *jinode,
|
|
loff_t new_size)
|
|
{
|
|
transaction_t *inode_trans, *commit_trans;
|
|
int ret = 0;
|
|
|
|
/* This is a quick check to avoid locking if not necessary */
|
|
if (!jinode->i_transaction)
|
|
goto out;
|
|
/* Locks are here just to force reading of recent values, it is
|
|
* enough that the transaction was not committing before we started
|
|
* a transaction adding the inode to orphan list */
|
|
read_lock(&journal->j_state_lock);
|
|
commit_trans = journal->j_committing_transaction;
|
|
read_unlock(&journal->j_state_lock);
|
|
spin_lock(&journal->j_list_lock);
|
|
inode_trans = jinode->i_transaction;
|
|
spin_unlock(&journal->j_list_lock);
|
|
if (inode_trans == commit_trans) {
|
|
ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping,
|
|
new_size, LLONG_MAX);
|
|
if (ret)
|
|
jbd2_journal_abort(journal, ret);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|