jbd2: fast commit recovery path
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>
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 79e947c..888d9d21 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1188,8 +1188,23 @@
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;
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index fb134c7..eb26061 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -35,7 +35,6 @@
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 @@
/* 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 @@
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 @@
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;
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index a009d9b..fb3d71a 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -751,6 +751,11 @@
#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 @@
*/
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) \
