![Jan Kara](/assets/img/avatar_default.png)
Toshiyuki Okajima found out that when running for ((i=0; i < 100000; i++)); do if ((i%2 == 0)); then chattr +j /mnt/file else chattr -j /mnt/file fi echo "0" >> /mnt/file done process sometimes hangs indefinitely in jbd2_journal_lock_updates(). Toshiyuki identified that the following race happens: jbd2_journal_lock_updates() |jbd2_journal_stop() ---------------------------------------+--------------------------------------- write_lock(&journal->j_state_lock) | . ++journal->j_barrier_count | . spin_lock(&tran->t_handle_lock) | . atomic_read(&tran->t_updates) //not 0 | | atomic_dec_and_test(&tran->t_updates) | // t_updates = 0 | wake_up(&journal->j_wait_updates) prepare_to_wait() | // no process is woken up. spin_unlock(&tran->t_handle_lock) | write_unlock(&journal->j_state_lock) | schedule() // never return | We fix the problem by first calling prepare_to_wait() and only after that checking t_updates in jbd2_journal_lock_updates(). Reported-and-analyzed-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2273 lines
68 KiB
C
2273 lines
68 KiB
C
/*
|
|
* linux/fs/jbd2/transaction.c
|
|
*
|
|
* Written by Stephen C. Tweedie <sct@redhat.com>, 1998
|
|
*
|
|
* Copyright 1998 Red Hat corp --- All Rights Reserved
|
|
*
|
|
* This file is part of the Linux kernel and is made available under
|
|
* the terms of the GNU General Public License, version 2, or at your
|
|
* option, any later version, incorporated herein by reference.
|
|
*
|
|
* Generic filesystem transaction handling code; part of the ext2fs
|
|
* journaling system.
|
|
*
|
|
* This file manages transactions (compound commits managed by the
|
|
* journaling code) and handles (individual atomic operations by the
|
|
* filesystem).
|
|
*/
|
|
|
|
#include <linux/time.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/jbd2.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/hrtimer.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/bug.h>
|
|
#include <linux/module.h>
|
|
|
|
static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
|
|
static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
|
|
|
|
/*
|
|
* jbd2_get_transaction: obtain a new transaction_t object.
|
|
*
|
|
* Simply allocate and initialise a new transaction. Create it in
|
|
* RUNNING state and add it to the current journal (which should not
|
|
* have an existing running transaction: we only make a new transaction
|
|
* once we have started to commit the old one).
|
|
*
|
|
* Preconditions:
|
|
* The journal MUST be locked. We don't perform atomic mallocs on the
|
|
* new transaction and we can't block without protecting against other
|
|
* processes trying to touch the journal while it is in transition.
|
|
*
|
|
*/
|
|
|
|
static transaction_t *
|
|
jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
|
|
{
|
|
transaction->t_journal = journal;
|
|
transaction->t_state = T_RUNNING;
|
|
transaction->t_start_time = ktime_get();
|
|
transaction->t_tid = journal->j_transaction_sequence++;
|
|
transaction->t_expires = jiffies + journal->j_commit_interval;
|
|
spin_lock_init(&transaction->t_handle_lock);
|
|
atomic_set(&transaction->t_updates, 0);
|
|
atomic_set(&transaction->t_outstanding_credits, 0);
|
|
atomic_set(&transaction->t_handle_count, 0);
|
|
INIT_LIST_HEAD(&transaction->t_inode_list);
|
|
INIT_LIST_HEAD(&transaction->t_private_list);
|
|
|
|
/* Set up the commit timer for the new transaction. */
|
|
journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires);
|
|
add_timer(&journal->j_commit_timer);
|
|
|
|
J_ASSERT(journal->j_running_transaction == NULL);
|
|
journal->j_running_transaction = transaction;
|
|
transaction->t_max_wait = 0;
|
|
transaction->t_start = jiffies;
|
|
|
|
return transaction;
|
|
}
|
|
|
|
/*
|
|
* Handle management.
|
|
*
|
|
* A handle_t is an object which represents a single atomic update to a
|
|
* filesystem, and which tracks all of the modifications which form part
|
|
* of that one update.
|
|
*/
|
|
|
|
/*
|
|
* Update transaction's maximum wait time, if debugging is enabled.
|
|
*
|
|
* In order for t_max_wait to be reliable, it must be protected by a
|
|
* lock. But doing so will mean that start_this_handle() can not be
|
|
* run in parallel on SMP systems, which limits our scalability. So
|
|
* unless debugging is enabled, we no longer update t_max_wait, which
|
|
* means that maximum wait time reported by the jbd2_run_stats
|
|
* tracepoint will always be zero.
|
|
*/
|
|
static inline void update_t_max_wait(transaction_t *transaction,
|
|
unsigned long ts)
|
|
{
|
|
#ifdef CONFIG_JBD2_DEBUG
|
|
if (jbd2_journal_enable_debug &&
|
|
time_after(transaction->t_start, ts)) {
|
|
ts = jbd2_time_diff(ts, transaction->t_start);
|
|
spin_lock(&transaction->t_handle_lock);
|
|
if (ts > transaction->t_max_wait)
|
|
transaction->t_max_wait = ts;
|
|
spin_unlock(&transaction->t_handle_lock);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* start_this_handle: Given a handle, deal with any locking or stalling
|
|
* needed to make sure that there is enough journal space for the handle
|
|
* to begin. Attach the handle to a transaction and set up the
|
|
* transaction's buffer credits.
|
|
*/
|
|
|
|
static int start_this_handle(journal_t *journal, handle_t *handle,
|
|
gfp_t gfp_mask)
|
|
{
|
|
transaction_t *transaction, *new_transaction = NULL;
|
|
tid_t tid;
|
|
int needed, need_to_start;
|
|
int nblocks = handle->h_buffer_credits;
|
|
unsigned long ts = jiffies;
|
|
|
|
if (nblocks > journal->j_max_transaction_buffers) {
|
|
printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
|
|
current->comm, nblocks,
|
|
journal->j_max_transaction_buffers);
|
|
return -ENOSPC;
|
|
}
|
|
|
|
alloc_transaction:
|
|
if (!journal->j_running_transaction) {
|
|
new_transaction = kzalloc(sizeof(*new_transaction), gfp_mask);
|
|
if (!new_transaction) {
|
|
/*
|
|
* If __GFP_FS is not present, then we may be
|
|
* being called from inside the fs writeback
|
|
* layer, so we MUST NOT fail. Since
|
|
* __GFP_NOFAIL is going away, we will arrange
|
|
* to retry the allocation ourselves.
|
|
*/
|
|
if ((gfp_mask & __GFP_FS) == 0) {
|
|
congestion_wait(BLK_RW_ASYNC, HZ/50);
|
|
goto alloc_transaction;
|
|
}
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
jbd_debug(3, "New handle %p going live.\n", handle);
|
|
|
|
/*
|
|
* We need to hold j_state_lock until t_updates has been incremented,
|
|
* for proper journal barrier handling
|
|
*/
|
|
repeat:
|
|
read_lock(&journal->j_state_lock);
|
|
BUG_ON(journal->j_flags & JBD2_UNMOUNT);
|
|
if (is_journal_aborted(journal) ||
|
|
(journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
|
|
read_unlock(&journal->j_state_lock);
|
|
kfree(new_transaction);
|
|
return -EROFS;
|
|
}
|
|
|
|
/* Wait on the journal's transaction barrier if necessary */
|
|
if (journal->j_barrier_count) {
|
|
read_unlock(&journal->j_state_lock);
|
|
wait_event(journal->j_wait_transaction_locked,
|
|
journal->j_barrier_count == 0);
|
|
goto repeat;
|
|
}
|
|
|
|
if (!journal->j_running_transaction) {
|
|
read_unlock(&journal->j_state_lock);
|
|
if (!new_transaction)
|
|
goto alloc_transaction;
|
|
write_lock(&journal->j_state_lock);
|
|
if (!journal->j_running_transaction) {
|
|
jbd2_get_transaction(journal, new_transaction);
|
|
new_transaction = NULL;
|
|
}
|
|
write_unlock(&journal->j_state_lock);
|
|
goto repeat;
|
|
}
|
|
|
|
transaction = journal->j_running_transaction;
|
|
|
|
/*
|
|
* If the current transaction is locked down for commit, wait for the
|
|
* lock to be released.
|
|
*/
|
|
if (transaction->t_state == T_LOCKED) {
|
|
DEFINE_WAIT(wait);
|
|
|
|
prepare_to_wait(&journal->j_wait_transaction_locked,
|
|
&wait, TASK_UNINTERRUPTIBLE);
|
|
read_unlock(&journal->j_state_lock);
|
|
schedule();
|
|
finish_wait(&journal->j_wait_transaction_locked, &wait);
|
|
goto repeat;
|
|
}
|
|
|
|
/*
|
|
* If there is not enough space left in the log to write all potential
|
|
* buffers requested by this operation, we need to stall pending a log
|
|
* checkpoint to free some more log space.
|
|
*/
|
|
needed = atomic_add_return(nblocks,
|
|
&transaction->t_outstanding_credits);
|
|
|
|
if (needed > journal->j_max_transaction_buffers) {
|
|
/*
|
|
* If the current transaction is already too large, then start
|
|
* to commit it: we can then go back and attach this handle to
|
|
* a new transaction.
|
|
*/
|
|
DEFINE_WAIT(wait);
|
|
|
|
jbd_debug(2, "Handle %p starting new commit...\n", handle);
|
|
atomic_sub(nblocks, &transaction->t_outstanding_credits);
|
|
prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
tid = transaction->t_tid;
|
|
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);
|
|
schedule();
|
|
finish_wait(&journal->j_wait_transaction_locked, &wait);
|
|
goto repeat;
|
|
}
|
|
|
|
/*
|
|
* The commit code assumes that it can get enough log space
|
|
* without forcing a checkpoint. This is *critical* for
|
|
* correctness: a checkpoint of a buffer which is also
|
|
* associated with a committing transaction creates a deadlock,
|
|
* so commit simply cannot force through checkpoints.
|
|
*
|
|
* We must therefore ensure the necessary space in the journal
|
|
* *before* starting to dirty potentially checkpointed buffers
|
|
* in the new transaction.
|
|
*
|
|
* The worst part is, any transaction currently committing can
|
|
* reduce the free space arbitrarily. Be careful to account for
|
|
* those buffers when checkpointing.
|
|
*/
|
|
|
|
/*
|
|
* @@@ AKPM: This seems rather over-defensive. We're giving commit
|
|
* a _lot_ of headroom: 1/4 of the journal plus the size of
|
|
* the committing transaction. Really, we only need to give it
|
|
* committing_transaction->t_outstanding_credits plus "enough" for
|
|
* the log control blocks.
|
|
* Also, this test is inconsistent with the matching one in
|
|
* jbd2_journal_extend().
|
|
*/
|
|
if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) {
|
|
jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle);
|
|
atomic_sub(nblocks, &transaction->t_outstanding_credits);
|
|
read_unlock(&journal->j_state_lock);
|
|
write_lock(&journal->j_state_lock);
|
|
if (__jbd2_log_space_left(journal) < jbd_space_needed(journal))
|
|
__jbd2_log_wait_for_space(journal);
|
|
write_unlock(&journal->j_state_lock);
|
|
goto repeat;
|
|
}
|
|
|
|
/* OK, account for the buffers that this operation expects to
|
|
* use and add the handle to the running transaction.
|
|
*/
|
|
update_t_max_wait(transaction, ts);
|
|
handle->h_transaction = transaction;
|
|
atomic_inc(&transaction->t_updates);
|
|
atomic_inc(&transaction->t_handle_count);
|
|
jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n",
|
|
handle, nblocks,
|
|
atomic_read(&transaction->t_outstanding_credits),
|
|
__jbd2_log_space_left(journal));
|
|
read_unlock(&journal->j_state_lock);
|
|
|
|
lock_map_acquire(&handle->h_lockdep_map);
|
|
kfree(new_transaction);
|
|
return 0;
|
|
}
|
|
|
|
static struct lock_class_key jbd2_handle_key;
|
|
|
|
/* Allocate a new handle. This should probably be in a slab... */
|
|
static handle_t *new_handle(int nblocks)
|
|
{
|
|
handle_t *handle = jbd2_alloc_handle(GFP_NOFS);
|
|
if (!handle)
|
|
return NULL;
|
|
memset(handle, 0, sizeof(*handle));
|
|
handle->h_buffer_credits = nblocks;
|
|
handle->h_ref = 1;
|
|
|
|
lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
|
|
&jbd2_handle_key, 0);
|
|
|
|
return handle;
|
|
}
|
|
|
|
/**
|
|
* handle_t *jbd2_journal_start() - Obtain a new handle.
|
|
* @journal: Journal to start transaction on.
|
|
* @nblocks: number of block buffer we might modify
|
|
*
|
|
* We make sure that the transaction can guarantee at least nblocks of
|
|
* modified buffers in the log. We block until the log can guarantee
|
|
* that much space.
|
|
*
|
|
* This function is visible to journal users (like ext3fs), so is not
|
|
* called with the journal already locked.
|
|
*
|
|
* Return a pointer to a newly allocated handle, or an ERR_PTR() value
|
|
* on failure.
|
|
*/
|
|
handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask)
|
|
{
|
|
handle_t *handle = journal_current_handle();
|
|
int err;
|
|
|
|
if (!journal)
|
|
return ERR_PTR(-EROFS);
|
|
|
|
if (handle) {
|
|
J_ASSERT(handle->h_transaction->t_journal == journal);
|
|
handle->h_ref++;
|
|
return handle;
|
|
}
|
|
|
|
handle = new_handle(nblocks);
|
|
if (!handle)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
current->journal_info = handle;
|
|
|
|
err = start_this_handle(journal, handle, gfp_mask);
|
|
if (err < 0) {
|
|
jbd2_free_handle(handle);
|
|
current->journal_info = NULL;
|
|
handle = ERR_PTR(err);
|
|
}
|
|
return handle;
|
|
}
|
|
EXPORT_SYMBOL(jbd2__journal_start);
|
|
|
|
|
|
handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
|
|
{
|
|
return jbd2__journal_start(journal, nblocks, GFP_NOFS);
|
|
}
|
|
EXPORT_SYMBOL(jbd2_journal_start);
|
|
|
|
|
|
/**
|
|
* 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 = transaction->t_journal;
|
|
int result;
|
|
int wanted;
|
|
|
|
result = -EIO;
|
|
if (is_handle_aborted(handle))
|
|
goto out;
|
|
|
|
result = 1;
|
|
|
|
read_lock(&journal->j_state_lock);
|
|
|
|
/* Don't extend a locked-down transaction! */
|
|
if (handle->h_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_read(&transaction->t_outstanding_credits) + nblocks;
|
|
|
|
if (wanted > journal->j_max_transaction_buffers) {
|
|
jbd_debug(3, "denied handle %p %d blocks: "
|
|
"transaction too large\n", handle, nblocks);
|
|
goto unlock;
|
|
}
|
|
|
|
if (wanted > __jbd2_log_space_left(journal)) {
|
|
jbd_debug(3, "denied handle %p %d blocks: "
|
|
"insufficient log space\n", handle, nblocks);
|
|
goto unlock;
|
|
}
|
|
|
|
handle->h_buffer_credits += nblocks;
|
|
atomic_add(nblocks, &transaction->t_outstanding_credits);
|
|
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);
|
|
out:
|
|
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.
|
|
*/
|
|
int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
|
|
{
|
|
transaction_t *transaction = handle->h_transaction;
|
|
journal_t *journal = transaction->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;
|
|
|
|
/*
|
|
* 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 (atomic_dec_and_test(&transaction->t_updates))
|
|
wake_up(&journal->j_wait_updates);
|
|
spin_unlock(&transaction->t_handle_lock);
|
|
|
|
jbd_debug(2, "restarting handle %p\n", handle);
|
|
tid = transaction->t_tid;
|
|
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 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;
|
|
journal_t *journal;
|
|
int error;
|
|
char *frozen_buffer = NULL;
|
|
int need_copy = 0;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EROFS;
|
|
|
|
transaction = handle->h_transaction;
|
|
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. */
|
|
|
|
lock_buffer(bh);
|
|
jbd_lock_bh_state(bh);
|
|
|
|
/* 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 (jh->b_jlist == BJ_Shadow) {
|
|
DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow);
|
|
wait_queue_head_t *wqh;
|
|
|
|
wqh = bit_waitqueue(&bh->b_state, BH_Unshadow);
|
|
|
|
JBUFFER_TRACE(jh, "on shadow: sleep");
|
|
jbd_unlock_bh_state(bh);
|
|
/* commit wakes up all shadow buffers after IO */
|
|
for ( ; ; ) {
|
|
prepare_to_wait(wqh, &wait.wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
if (jh->b_jlist != BJ_Shadow)
|
|
break;
|
|
schedule();
|
|
}
|
|
finish_wait(wqh, &wait.wait);
|
|
goto repeat;
|
|
}
|
|
|
|
/* Only do the copy if the currently-owning transaction
|
|
* still needs it. If it is on the Forget list, the
|
|
* committing transaction is past that stage. The
|
|
* buffer had better remain locked during the kmalloc,
|
|
* but that should be true --- we hold the journal lock
|
|
* still and the buffer is already on the BUF_JOURNAL
|
|
* list so won't be flushed.
|
|
*
|
|
* 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_Forget || 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_EMERG
|
|
"%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, KM_USER0);
|
|
/* 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, KM_USER0);
|
|
|
|
/*
|
|
* 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 = transaction->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;
|
|
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);
|
|
spin_lock(&journal->j_list_lock);
|
|
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");
|
|
__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");
|
|
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_EMERG "%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 = bh2jh(bh);
|
|
|
|
jh->b_triggers = type;
|
|
}
|
|
|
|
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 = transaction->t_journal;
|
|
struct journal_head *jh = bh2jh(bh);
|
|
int ret = 0;
|
|
|
|
jbd_debug(5, "journal_head %p\n", jh);
|
|
JBUFFER_TRACE(jh, "entry");
|
|
if (is_handle_aborted(handle))
|
|
goto out;
|
|
if (!buffer_jbd(bh)) {
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
|
|
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;
|
|
J_ASSERT_JH(jh, handle->h_buffer_credits > 0);
|
|
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_EMERG "JBD: %s: "
|
|
"jh->b_transaction (%llu, %p, %u) != "
|
|
"journal->j_running_transaction (%p, %u)",
|
|
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)) {
|
|
printk(KERN_EMERG "JBD: %s: "
|
|
"jh->b_transaction (%llu, %p, %u) != "
|
|
"journal->j_committing_transaction (%p, %u)",
|
|
journal->j_devname,
|
|
(unsigned long long) bh->b_blocknr,
|
|
jh->b_transaction,
|
|
jh->b_transaction ? jh->b_transaction->t_tid : 0,
|
|
journal->j_committing_transaction,
|
|
journal->j_committing_transaction ?
|
|
journal->j_committing_transaction->t_tid : 0);
|
|
ret = -EINVAL;
|
|
}
|
|
if (unlikely(jh->b_next_transaction != transaction)) {
|
|
printk(KERN_EMERG "JBD: %s: "
|
|
"jh->b_next_transaction (%llu, %p, %u) != "
|
|
"transaction (%p, %u)",
|
|
journal->j_devname,
|
|
(unsigned long long) bh->b_blocknr,
|
|
jh->b_next_transaction,
|
|
jh->b_next_transaction ?
|
|
jh->b_next_transaction->t_tid : 0,
|
|
transaction, transaction->t_tid);
|
|
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, handle->h_transaction, BJ_Metadata);
|
|
spin_unlock(&journal->j_list_lock);
|
|
out_unlock_bh:
|
|
jbd_unlock_bh_state(bh);
|
|
out:
|
|
JBUFFER_TRACE(jh, "exit");
|
|
WARN_ON(ret); /* All errors are bugs, so dump the stack */
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* jbd2_journal_release_buffer: undo a get_write_access without any buffer
|
|
* updates, if the update decided in the end that it didn't need access.
|
|
*
|
|
*/
|
|
void
|
|
jbd2_journal_release_buffer(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
BUFFER_TRACE(bh, "entry");
|
|
}
|
|
|
|
/**
|
|
* 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 = transaction->t_journal;
|
|
struct journal_head *jh;
|
|
int drop_reserve = 0;
|
|
int err = 0;
|
|
int was_modified = 0;
|
|
|
|
BUFFER_TRACE(bh, "entry");
|
|
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
|
|
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 wether 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 == handle->h_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.
|
|
*/
|
|
|
|
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;
|
|
}
|
|
}
|
|
} 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);
|
|
jh->b_next_transaction = NULL;
|
|
|
|
/*
|
|
* only drop a reference if this transaction modified
|
|
* the buffer
|
|
*/
|
|
if (was_modified)
|
|
drop_reserve = 1;
|
|
}
|
|
}
|
|
|
|
not_jbd:
|
|
spin_unlock(&journal->j_list_lock);
|
|
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 = transaction->t_journal;
|
|
int err, wait_for_commit = 0;
|
|
tid_t tid;
|
|
pid_t pid;
|
|
|
|
J_ASSERT(journal_current_handle() == handle);
|
|
|
|
if (is_handle_aborted(handle))
|
|
err = -EIO;
|
|
else {
|
|
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
|
|
err = 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);
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
pid = current->pid;
|
|
if (handle->h_sync && journal->j_last_sync_writer != pid) {
|
|
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);
|
|
|
|
jbd2_free_handle(handle);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* int jbd2_journal_force_commit() - force any uncommitted transactions
|
|
* @journal: journal to force
|
|
*
|
|
* For synchronous operations: force any uncommitted transactions
|
|
* to disk. May seem kludgy, but it reuses all the handle batching
|
|
* code in a very simple manner.
|
|
*/
|
|
int jbd2_journal_force_commit(journal_t *journal)
|
|
{
|
|
handle_t *handle;
|
|
int ret;
|
|
|
|
handle = jbd2_journal_start(journal, 1);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
} else {
|
|
handle->h_sync = 1;
|
|
ret = jbd2_journal_stop(handle);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
*
|
|
* 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_iobuf_list, 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. The journal may not be locked.
|
|
*/
|
|
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_IO:
|
|
list = &transaction->t_iobuf_list;
|
|
break;
|
|
case BJ_Shadow:
|
|
list = &transaction->t_shadow_list;
|
|
break;
|
|
case BJ_LogCtl:
|
|
list = &transaction->t_log_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)
|
|
goto out;
|
|
|
|
spin_lock(&journal->j_list_lock);
|
|
if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
|
|
/* written-back checkpointed metadata buffer */
|
|
if (jh->b_jlist == BJ_None) {
|
|
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)
|
|
{
|
|
transaction_t *transaction;
|
|
struct journal_head *jh;
|
|
int may_free = 1;
|
|
int ret;
|
|
|
|
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
|
|
* buffer 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.
|
|
*/
|
|
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");
|
|
ret = __dispose_buffer(jh,
|
|
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 ret;
|
|
} 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");
|
|
ret = __dispose_buffer(jh,
|
|
journal->j_committing_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 ret;
|
|
} 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. So 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:
|
|
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);
|
|
bh->b_bdev = NULL;
|
|
return may_free;
|
|
}
|
|
|
|
/**
|
|
* void jbd2_journal_invalidatepage()
|
|
* @journal: journal to use for flush...
|
|
* @page: page to flush
|
|
* @offset: length of page to invalidate.
|
|
*
|
|
* Reap page buffers containing data after offset in page.
|
|
*
|
|
*/
|
|
void jbd2_journal_invalidatepage(journal_t *journal,
|
|
struct page *page,
|
|
unsigned long offset)
|
|
{
|
|
struct buffer_head *head, *bh, *next;
|
|
unsigned int curr_off = 0;
|
|
int may_free = 1;
|
|
|
|
if (!PageLocked(page))
|
|
BUG();
|
|
if (!page_has_buffers(page))
|
|
return;
|
|
|
|
/* 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 (offset <= curr_off) {
|
|
/* This block is wholly outside the truncation point */
|
|
lock_buffer(bh);
|
|
may_free &= journal_unmap_buffer(journal, bh);
|
|
unlock_buffer(bh);
|
|
}
|
|
curr_off = next_off;
|
|
bh = next;
|
|
|
|
} while (bh != head);
|
|
|
|
if (!offset) {
|
|
if (may_free && try_to_free_buffers(page))
|
|
J_ASSERT(!page_has_buffers(page));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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_IO:
|
|
list = &transaction->t_iobuf_list;
|
|
break;
|
|
case BJ_Shadow:
|
|
list = &transaction->t_shadow_list;
|
|
break;
|
|
case BJ_LogCtl:
|
|
list = &transaction->t_log_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 = transaction->t_journal;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return -EIO;
|
|
|
|
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;
|
|
}
|