tree 161c471b03b931d2e439d7c8ab6e03d5a75a8709
parent caecd0af8fe0635e8e6900399b951433af35bf52
author Eric Sandeen <sandeen@redhat.com> 1345343380 -0400
committer Theodore Ts'o <tytso@mit.edu> 1345343380 -0400

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