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author | Michael Tokarev <mjt@tls.msk.ru> | 2012-12-25 14:08:16 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-17 08:43:57 -0800 |
commit | 1ba9a27ec24b133799bc1b8a77d733c4015d0abd (patch) | |
tree | 106791a88f3767d40e74d4fb440cbb52f54d0ced | |
parent | 7c558b7eb837ca7bc014af2f5509be143c3c3670 (diff) | |
download | lwn-1ba9a27ec24b133799bc1b8a77d733c4015d0abd.tar.gz lwn-1ba9a27ec24b133799bc1b8a77d733c4015d0abd.zip |
ext4: do not try to write superblock on ro remount w/o journal
commit d096ad0f79a782935d2e06ae8fb235e8c5397775 upstream.
When a journal-less ext4 filesystem is mounted on a read-only block
device (blockdev --setro will do), each remount (for other, unrelated,
flags, like suid=>nosuid etc) results in a series of scary messages
from kernel telling about I/O errors on the device.
This is becauese of the following code ext4_remount():
if (sbi->s_journal == NULL)
ext4_commit_super(sb, 1);
at the end of remount procedure, which forces writing (flushing) of
a superblock regardless whenever it is dirty or not, if the filesystem
is readonly or not, and whenever the device itself is readonly or not.
We only need call ext4_commit_super when the file system had been
previously mounted read/write.
Thanks to Eric Sandeen for help in diagnosing this issue.
Signed-off-By: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | fs/ext4/super.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 489d406c0d7c..9ca954e1d5ff 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4438,7 +4438,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) } ext4_setup_system_zone(sb); - if (sbi->s_journal == NULL) + if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY)) ext4_commit_super(sb, 1); #ifdef CONFIG_QUOTA |