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jbd2: fast commit recovery path

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This patch adds fast commit recovery support in JBD2.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-7-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Harshad Shirwadkar 2020-10-15 13:37:58 -07:00 committed by Theodore Ts'o
parent aa75f4d3da
commit 5b849b5f96
3 changed files with 88 additions and 4 deletions
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15
fs/ext4/fast_commit.c
View File

@ -1188,8 +1188,23 @@ static void ext4_fc_cleanup(journal_t *journal, int full)
trace_ext4_fc_stats(sb);
}
/*
* Main recovery path entry point.
*/
static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
enum passtype pass, int off, tid_t expected_tid)
{
return 0;
}
void ext4_fc_init(struct super_block *sb, journal_t *journal)
{
/*
* We set replay callback even if fast commit disabled because we may
* could still have fast commit blocks that need to be replayed even if
* fast commit has now been turned off.
*/
journal->j_fc_replay_callback = ext4_fc_replay;
if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
return;
journal->j_fc_cleanup_callback = ext4_fc_cleanup;

57
fs/jbd2/recovery.c
View File

@ -35,7 +35,6 @@ struct recovery_info
int nr_revoke_hits;
};
enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
static int do_one_pass(journal_t *journal,
struct recovery_info *info, enum passtype pass);
static int scan_revoke_records(journal_t *, struct buffer_head *,
@ -225,10 +224,51 @@ static int count_tags(journal_t *journal, struct buffer_head *bh)
/* Make sure we wrap around the log correctly! */
#define wrap(journal, var) \
do { \
if (var >= (journal)->j_last) \
var -= ((journal)->j_last - (journal)->j_first); \
unsigned long _wrap_last = \
jbd2_has_feature_fast_commit(journal) ? \
(journal)->j_fc_last : (journal)->j_last; \
\
if (var >= _wrap_last) \
var -= (_wrap_last - (journal)->j_first); \
} while (0)
static int fc_do_one_pass(journal_t *journal,
struct recovery_info *info, enum passtype pass)
{
unsigned int expected_commit_id = info->end_transaction;
unsigned long next_fc_block;
struct buffer_head *bh;
int err = 0;
next_fc_block = journal->j_fc_first;
if (!journal->j_fc_replay_callback)
return 0;
while (next_fc_block <= journal->j_fc_last) {
jbd_debug(3, "Fast commit replay: next block %ld",
next_fc_block);
err = jread(&bh, journal, next_fc_block);
if (err) {
jbd_debug(3, "Fast commit replay: read error");
break;
}
jbd_debug(3, "Processing fast commit blk with seq %d");
err = journal->j_fc_replay_callback(journal, bh, pass,
next_fc_block - journal->j_fc_first,
expected_commit_id);
next_fc_block++;
if (err < 0 || err == JBD2_FC_REPLAY_STOP)
break;
err = 0;
}
if (err)
jbd_debug(3, "Fast commit replay failed, err = %d\n", err);
return err;
}
/**
* jbd2_journal_recover - recovers a on-disk journal
* @journal: the journal to recover
@ -472,7 +512,9 @@ static int do_one_pass(journal_t *journal,
break;
jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
next_commit_ID, next_log_block, journal->j_last);
next_commit_ID, next_log_block,
jbd2_has_feature_fast_commit(journal) ?
journal->j_fc_last : journal->j_last);
/* Skip over each chunk of the transaction looking
* either the next descriptor block or the final commit
@ -834,6 +876,13 @@ static int do_one_pass(journal_t *journal,
success = -EIO;
}
}
if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) {
err = fc_do_one_pass(journal, info, pass);
if (err)
success = err;
}
if (block_error && success == 0)
success = -EIO;
return success;

20
include/linux/jbd2.h
View File

@ -751,6 +751,11 @@ jbd2_time_diff(unsigned long start, unsigned long end)
#define JBD2_NR_BATCH 64
enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
#define JBD2_FC_REPLAY_STOP 0
#define JBD2_FC_REPLAY_CONTINUE 1
/**
* struct journal_s - The journal_s type is the concrete type associated with
* journal_t.
@ -1248,6 +1253,21 @@ struct journal_s
*/
void (*j_fc_cleanup_callback)(struct journal_s *journal, int);
/*
* @j_fc_replay_callback:
*
* File-system specific function that performs replay of a fast
* commit. JBD2 calls this function for each fast commit block found in
* the journal. This function should return JBD2_FC_REPLAY_CONTINUE
* to indicate that the block was processed correctly and more fast
* commit replay should continue. Return value of JBD2_FC_REPLAY_STOP
* indicates the end of replay (no more blocks remaining). A negative
* return value indicates error.
*/
int (*j_fc_replay_callback)(struct journal_s *journal,
struct buffer_head *bh,
enum passtype pass, int off,
tid_t expected_commit_id);
};
#define jbd2_might_wait_for_commit(j) \