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authorEric Sandeen <sandeen@redhat.com>2012-08-18 22:29:40 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-08-18 22:29:40 -0400
commiteeecef0af5ea4efd763c9554cf2bd80fc4a0efd3 (patch)
tree161c471b03b931d2e439d7c8ab6e03d5a75a8709 /fs/jbd2
parentcaecd0af8fe0635e8e6900399b951433af35bf52 (diff)
downloadblackbird-op-linux-eeecef0af5ea4efd763c9554cf2bd80fc4a0efd3.tar.gz
blackbird-op-linux-eeecef0af5ea4efd763c9554cf2bd80fc4a0efd3.zip
jbd2: don't write superblock when if its empty
This sequence: # truncate --size=1g fsfile # mkfs.ext4 -F fsfile # mount -o loop,ro fsfile /mnt # umount /mnt # dmesg | tail results in an IO error when unmounting the RO filesystem: [ 318.020828] Buffer I/O error on device loop1, logical block 196608 [ 318.027024] lost page write due to I/O error on loop1 [ 318.032088] JBD2: Error -5 detected when updating journal superblock for loop1-8. This was a regression introduced by commit 24bcc89c7e7c: "jbd2: split updating of journal superblock and marking journal empty". Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/jbd2')
-rw-r--r--fs/jbd2/journal.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index bd23f2ebaa67..0f16edd51f67 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1354,6 +1354,11 @@ static void jbd2_mark_journal_empty(journal_t *journal)
BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
read_lock(&journal->j_state_lock);
+ /* Is it already empty? */
+ if (sb->s_start == 0) {
+ read_unlock(&journal->j_state_lock);
+ return;
+ }
jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
journal->j_tail_sequence);
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