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jbd2: add fast commit machinery

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This functions adds necessary APIs needed in JBD2 layer for fast
commits.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-5-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Harshad Shirwadkar 2020-10-15 13:37:56 -07:00 committed by Theodore Ts'o
parent 6866d7b3f2
commit ff780b91ef
4 changed files with 268 additions and 1 deletions
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8
fs/ext4/fast_commit.c
View File

@ -8,11 +8,19 @@
* Ext4 fast commits routines.
*/
#include "ext4_jbd2.h"
/*
* Fast commit cleanup routine. This is called after every fast commit and
* full commit. full is true if we are called after a full commit.
*/
static void ext4_fc_cleanup(journal_t *journal, int full)
{
}
void ext4_fc_init(struct super_block *sb, journal_t *journal)
{
if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
return;
journal->j_fc_cleanup_callback = ext4_fc_cleanup;
if (jbd2_fc_init(journal, EXT4_NUM_FC_BLKS)) {
pr_warn("Error while enabling fast commits, turning off.");
ext4_clear_feature_fast_commit(sb);

44
fs/jbd2/commit.c
View File

@ -206,6 +206,30 @@ int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
return generic_writepages(mapping, &wbc);
}
/* Send all the data buffers related to an inode */
int jbd2_submit_inode_data(struct jbd2_inode *jinode)
{
if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
return 0;
trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
return jbd2_journal_submit_inode_data_buffers(jinode);
}
EXPORT_SYMBOL(jbd2_submit_inode_data);
int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
{
if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
!jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
return 0;
return filemap_fdatawait_range_keep_errors(
jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
jinode->i_dirty_end);
}
EXPORT_SYMBOL(jbd2_wait_inode_data);
/*
* Submit all the data buffers of inode associated with the transaction to
* disk.
@ -415,6 +439,20 @@ void jbd2_journal_commit_transaction(journal_t *journal)
J_ASSERT(journal->j_running_transaction != NULL);
J_ASSERT(journal->j_committing_transaction == NULL);
write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
DEFINE_WAIT(wait);
prepare_to_wait(&journal->j_fc_wait, &wait,
TASK_UNINTERRUPTIBLE);
write_unlock(&journal->j_state_lock);
schedule();
write_lock(&journal->j_state_lock);
finish_wait(&journal->j_fc_wait, &wait);
}
write_unlock(&journal->j_state_lock);
commit_transaction = journal->j_running_transaction;
trace_jbd2_start_commit(journal, commit_transaction);
@ -422,6 +460,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
commit_transaction->t_tid);
write_lock(&journal->j_state_lock);
journal->j_fc_off = 0;
J_ASSERT(commit_transaction->t_state == T_RUNNING);
commit_transaction->t_state = T_LOCKED;
@ -1121,12 +1160,16 @@ restart_loop:
if (journal->j_commit_callback)
journal->j_commit_callback(journal, commit_transaction);
if (journal->j_fc_cleanup_callback)
journal->j_fc_cleanup_callback(journal, 1);
trace_jbd2_end_commit(journal, commit_transaction);
jbd_debug(1, "JBD2: commit %d complete, head %d\n",
journal->j_commit_sequence, journal->j_tail_sequence);
write_lock(&journal->j_state_lock);
journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
spin_lock(&journal->j_list_lock);
commit_transaction->t_state = T_FINISHED;
/* Check if the transaction can be dropped now that we are finished */
@ -1138,6 +1181,7 @@ restart_loop:
spin_unlock(&journal->j_list_lock);
write_unlock(&journal->j_state_lock);
wake_up(&journal->j_wait_done_commit);
wake_up(&journal->j_fc_wait);
/*
* Calculate overall stats

190
fs/jbd2/journal.c
View File

@ -159,7 +159,9 @@ static void commit_timeout(struct timer_list *t)
*
* 1) COMMIT: Every so often we need to commit the current state of the
* filesystem to disk. The journal thread is responsible for writing
* all of the metadata buffers to disk.
* all of the metadata buffers to disk. If a fast commit is ongoing
* journal thread waits until it's done and then continues from
* there on.
*
* 2) CHECKPOINT: We cannot reuse a used section of the log file until all
* of the data in that part of the log has been rewritten elsewhere on
@ -716,6 +718,75 @@ int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
return err;
}
/*
* Start a fast commit. If there's an ongoing fast or full commit wait for
* it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY
* if a fast commit is not needed, either because there's an already a commit
* going on or this tid has already been committed. Returns -EINVAL if no jbd2
* commit has yet been performed.
*/
int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
{
/*
* Fast commits only allowed if at least one full commit has
* been processed.
*/
if (!journal->j_stats.ts_tid)
return -EINVAL;
if (tid <= journal->j_commit_sequence)
return -EALREADY;
write_lock(&journal->j_state_lock);
if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
(journal->j_flags & JBD2_FAST_COMMIT_ONGOING)) {
DEFINE_WAIT(wait);
prepare_to_wait(&journal->j_fc_wait, &wait,
TASK_UNINTERRUPTIBLE);
write_unlock(&journal->j_state_lock);
schedule();
finish_wait(&journal->j_fc_wait, &wait);
return -EALREADY;
}
journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
write_unlock(&journal->j_state_lock);
return 0;
}
EXPORT_SYMBOL(jbd2_fc_begin_commit);
/*
* Stop a fast commit. If fallback is set, this function starts commit of
* TID tid before any other fast commit can start.
*/
static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
{
if (journal->j_fc_cleanup_callback)
journal->j_fc_cleanup_callback(journal, 0);
write_lock(&journal->j_state_lock);
journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
if (fallback)
journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
write_unlock(&journal->j_state_lock);
wake_up(&journal->j_fc_wait);
if (fallback)
return jbd2_complete_transaction(journal, tid);
return 0;
}
int jbd2_fc_end_commit(journal_t *journal)
{
return __jbd2_fc_end_commit(journal, 0, 0);
}
EXPORT_SYMBOL(jbd2_fc_end_commit);
int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid)
{
return __jbd2_fc_end_commit(journal, tid, 1);
}
EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
/* Return 1 when transaction with given tid has already committed. */
int jbd2_transaction_committed(journal_t *journal, tid_t tid)
{
@ -784,6 +855,110 @@ int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
return jbd2_journal_bmap(journal, blocknr, retp);
}
/* Map one fast commit buffer for use by the file system */
int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
{
unsigned long long pblock;
unsigned long blocknr;
int ret = 0;
struct buffer_head *bh;
int fc_off;
*bh_out = NULL;
write_lock(&journal->j_state_lock);
if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) {
fc_off = journal->j_fc_off;
blocknr = journal->j_fc_first + fc_off;
journal->j_fc_off++;
} else {
ret = -EINVAL;
}
write_unlock(&journal->j_state_lock);
if (ret)
return ret;
ret = jbd2_journal_bmap(journal, blocknr, &pblock);
if (ret)
return ret;
bh = __getblk(journal->j_dev, pblock, journal->j_blocksize);
if (!bh)
return -ENOMEM;
lock_buffer(bh);
clear_buffer_uptodate(bh);
set_buffer_dirty(bh);
unlock_buffer(bh);
journal->j_fc_wbuf[fc_off] = bh;
*bh_out = bh;
return 0;
}
EXPORT_SYMBOL(jbd2_fc_get_buf);
/*
* Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
* for completion.
*/
int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
{
struct buffer_head *bh;
int i, j_fc_off;
read_lock(&journal->j_state_lock);
j_fc_off = journal->j_fc_off;
read_unlock(&journal->j_state_lock);
/*
* Wait in reverse order to minimize chances of us being woken up before
* all IOs have completed
*/
for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) {
bh = journal->j_fc_wbuf[i];
wait_on_buffer(bh);
put_bh(bh);
journal->j_fc_wbuf[i] = NULL;
if (unlikely(!buffer_uptodate(bh)))
return -EIO;
}
return 0;
}
EXPORT_SYMBOL(jbd2_fc_wait_bufs);
/*
* Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
* for completion.
*/
int jbd2_fc_release_bufs(journal_t *journal)
{
struct buffer_head *bh;
int i, j_fc_off;
read_lock(&journal->j_state_lock);
j_fc_off = journal->j_fc_off;
read_unlock(&journal->j_state_lock);
/*
* Wait in reverse order to minimize chances of us being woken up before
* all IOs have completed
*/
for (i = j_fc_off - 1; i >= 0; i--) {
bh = journal->j_fc_wbuf[i];
if (!bh)
break;
put_bh(bh);
journal->j_fc_wbuf[i] = NULL;
}
return 0;
}
EXPORT_SYMBOL(jbd2_fc_release_bufs);
/*
* Conversion of logical to physical block numbers for the journal
*
@ -1142,6 +1317,7 @@ static journal_t *journal_init_common(struct block_device *bdev,
init_waitqueue_head(&journal->j_wait_commit);
init_waitqueue_head(&journal->j_wait_updates);
init_waitqueue_head(&journal->j_wait_reserved);
init_waitqueue_head(&journal->j_fc_wait);
mutex_init(&journal->j_abort_mutex);
mutex_init(&journal->j_barrier);
mutex_init(&journal->j_checkpoint_mutex);
@ -1495,6 +1671,7 @@ out:
static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
{
journal_superblock_t *sb = journal->j_superblock;
bool had_fast_commit = false;
BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
lock_buffer(journal->j_sb_buffer);
@ -1508,9 +1685,20 @@ static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
sb->s_start = cpu_to_be32(0);
if (jbd2_has_feature_fast_commit(journal)) {
/*
* When journal is clean, no need to commit fast commit flag and
* make file system incompatible with older kernels.
*/
jbd2_clear_feature_fast_commit(journal);
had_fast_commit = true;
}
jbd2_write_superblock(journal, write_op);
if (had_fast_commit)
jbd2_set_feature_fast_commit(journal);
/* Log is no longer empty */
write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_FLUSHED;

27
include/linux/jbd2.h
View File

@ -861,6 +861,13 @@ struct journal_s
*/
wait_queue_head_t j_wait_reserved;
/**
* @j_fc_wait:
*
* Wait queue to wait for completion of async fast commits.
*/
wait_queue_head_t j_fc_wait;
/**
* @j_checkpoint_mutex:
*
@ -1232,6 +1239,15 @@ struct journal_s
*/
struct lockdep_map j_trans_commit_map;
#endif
/**
* @j_fc_cleanup_callback:
*
* Clean-up after fast commit or full commit. JBD2 calls this function
* after every commit operation.
*/
void (*j_fc_cleanup_callback)(struct journal_s *journal, int);
};
#define jbd2_might_wait_for_commit(j) \
@ -1316,6 +1332,8 @@ JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit, FAST_COMMIT)
#define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file
* data write error in ordered
* mode */
#define JBD2_FAST_COMMIT_ONGOING 0x100 /* Fast commit is ongoing */
#define JBD2_FULL_COMMIT_ONGOING 0x200 /* Full commit is ongoing */
/*
* Function declarations for the journaling transaction and buffer
@ -1574,6 +1592,15 @@ extern int jbd2_cleanup_journal_tail(journal_t *);
/* Fast commit related APIs */
int jbd2_fc_init(journal_t *journal, int num_fc_blks);
int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
int jbd2_fc_end_commit(journal_t *journal);
int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid);
int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
int jbd2_submit_inode_data(struct jbd2_inode *jinode);
int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
int jbd2_fc_release_bufs(journal_t *journal);
/*
* is_journal_abort
*