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authorJan Kara <jack@suse.cz>2012-03-13 15:43:04 -0400
committerBen Hutchings <ben@decadent.org.uk>2015-10-13 03:46:00 +0100
commit7f63bfd0051575b4487f2e17b44e2cc4eb39384b (patch)
treeae7ac01ff679b16e93bcf2113b3f512a06919ac7 /fs
parent516aa86b9ffaa8daba9dd3e8ef16350ffafbb25e (diff)
jbd2: protect all log tail updates with j_checkpoint_mutex
commit a78bb11d7acd525623c6a0c2ff4e213d527573fa upstream. There are some log tail updates that are not protected by j_checkpoint_mutex. Some of these are harmless because they happen during startup or shutdown but updates in jbd2_journal_commit_transaction() and jbd2_journal_flush() can really race with other log tail updates (e.g. someone doing jbd2_journal_flush() with someone running jbd2_cleanup_journal_tail()). So protect all log tail updates with j_checkpoint_mutex. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> [bwh: Backported to 3.2: - Adjust context - Add unlock on the error path in jbd2_journal_flush()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Bartosz Kwitniewski <zerg2000@astral.org.pl>
Diffstat (limited to 'fs')
-rw-r--r--fs/jbd2/commit.c2
-rw-r--r--fs/jbd2/journal.c23
2 files changed, 21 insertions, 4 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index bccb60533f93..b6c3c14052f8 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -340,6 +340,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
/* Do we need to erase the effects of a prior jbd2_journal_flush? */
if (journal->j_flags & JBD2_FLUSHED) {
jbd_debug(3, "super block updated\n");
+ mutex_lock(&journal->j_checkpoint_mutex);
/*
* We hold j_checkpoint_mutex so tail cannot change under us.
* We don't need any special data guarantees for writing sb
@@ -350,6 +351,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
journal->j_tail_sequence,
journal->j_tail,
WRITE_SYNC);
+ mutex_unlock(&journal->j_checkpoint_mutex);
} else {
jbd_debug(3, "superblock not updated\n");
}
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 9532dac46e94..629081559642 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1242,6 +1242,8 @@ static int journal_reset(journal_t *journal)
journal->j_errno);
journal->j_flags |= JBD2_FLUSHED;
} else {
+ /* Lock here to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
/*
* Update log tail information. We use WRITE_FUA since new
* transaction will start reusing journal space and so we
@@ -1252,6 +1254,7 @@ static int journal_reset(journal_t *journal)
journal->j_tail_sequence,
journal->j_tail,
WRITE_FUA);
+ mutex_unlock(&journal->j_checkpoint_mutex);
}
return jbd2_journal_start_thread(journal);
}
@@ -1314,6 +1317,7 @@ int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
journal_superblock_t *sb = journal->j_superblock;
int ret;
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
tail_block, tail_tid);
@@ -1344,6 +1348,7 @@ static void jbd2_mark_journal_empty(journal_t *journal)
{
journal_superblock_t *sb = journal->j_superblock;
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
read_lock(&journal->j_state_lock);
jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
journal->j_tail_sequence);
@@ -1577,9 +1582,11 @@ int jbd2_journal_destroy(journal_t *journal)
spin_unlock(&journal->j_list_lock);
if (journal->j_sb_buffer) {
- if (!is_journal_aborted(journal))
+ if (!is_journal_aborted(journal)) {
+ mutex_lock(&journal->j_checkpoint_mutex);
jbd2_mark_journal_empty(journal);
- else
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ } else
err = -EIO;
brelse(journal->j_sb_buffer);
}
@@ -1828,10 +1835,13 @@ int jbd2_journal_flush(journal_t *journal)
if (is_journal_aborted(journal))
return -EIO;
+ mutex_lock(&journal->j_checkpoint_mutex);
if (!err) {
err = jbd2_cleanup_journal_tail(journal);
- if (err < 0)
+ if (err < 0) {
+ mutex_unlock(&journal->j_checkpoint_mutex);
goto out;
+ }
err = 0;
}
@@ -1841,6 +1851,7 @@ int jbd2_journal_flush(journal_t *journal)
* commits of data to the journal will restore the current
* s_start value. */
jbd2_mark_journal_empty(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
write_lock(&journal->j_state_lock);
J_ASSERT(!journal->j_running_transaction);
J_ASSERT(!journal->j_committing_transaction);
@@ -1882,8 +1893,12 @@ int jbd2_journal_wipe(journal_t *journal, int write)
write ? "Clearing" : "Ignoring");
err = jbd2_journal_skip_recovery(journal);
- if (write)
+ if (write) {
+ /* Lock to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
jbd2_mark_journal_empty(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
no_recovery:
return err;