[PATCH 2/8] jbd2: Protect all log tail updates with j_checkpoint_mutex
From: Jan Kara <jack@suse.cz>
Date: 2012-02-15 18:34:40
Subsystem:
filesystems (vfs and infrastructure), journalling layer for block devices (jbd2), the rest · Maintainers:
Alexander Viro, Christian Brauner, "Theodore Ts'o", Jan Kara, Linus Torvalds
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> --- fs/jbd2/commit.c | 2 ++ fs/jbd2/journal.c | 19 ++++++++++++++++--- 2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index ffdf512..39978c1 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c@@ -340,7 +340,9 @@ 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); jbd2_journal_update_sb_log_tail(journal); + 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 ec05900..183a099 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c@@ -1125,8 +1125,11 @@ 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); /* Add the dynamic fields and write it to disk. */ jbd2_journal_update_sb_log_tail(journal); + mutex_unlock(&journal->j_checkpoint_mutex); } return jbd2_journal_start_thread(journal); }
@@ -1174,6 +1177,7 @@ void jbd2_journal_update_sb_log_tail(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: updating superblock (start %ld, seq %d)\n", journal->j_tail, journal->j_tail_sequence);
@@ -1202,6 +1206,7 @@ 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);
@@ -1435,9 +1440,11 @@ 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); }
@@ -1686,6 +1693,7 @@ int jbd2_journal_flush(journal_t *journal) if (is_journal_aborted(journal)) return -EIO; + mutex_lock(&journal->j_checkpoint_mutex); jbd2_cleanup_journal_tail(journal); /* Finally, mark the journal as really needing no recovery.
@@ -1694,6 +1702,7 @@ 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);
@@ -1734,8 +1743,12 @@ 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;
--
1.7.1