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jbd: protect all log tail updates with j_checkpoint_mutex

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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 journal_commit_transaction() and journal_flush() can really race
with other log tail updates (e.g. someone doing journal_flush() with someone
running cleanup_journal_tail()). So protect all log tail updates with
j_checkpoint_mutex.

Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara
2012-04-07 12:50:13 +02:00
parent 9754e39c7b
commit 1ce8486dcc
2 changed files with 17 additions and 1 deletions
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2
fs/jbd/commit.c
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@@ -308,7 +308,9 @@ void journal_commit_transaction(journal_t *journal)
/* Do we need to erase the effects of a prior journal_flush? */
if (journal->j_flags & JFS_FLUSHED) {
jbd_debug(3, "super block updated\n");
mutex_lock(&journal->j_checkpoint_mutex);
journal_update_sb_log_tail(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
} else {
jbd_debug(3, "superblock not updated\n");
}