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ext4: Fix fsync error handling after filesystem abort 

If filesystem was aborted after inode's write back is complete
but before its metadata was updated we may return success
results in data loss.
In order to handle fs abort correctly we have to check
fs state once we discover that it is in MS_RDONLY state

Test case: http://patchwork.ozlabs.org/patch/244297

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Dmitry Monakhov 2013-06-12 22:38:04 -04:00 committed by Theodore Ts'o
parent 06a407f13d
commit 4418e14112
2 changed files with 17 additions and 2 deletions
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7
fs/ext4/fsync.c
View File

@ -98,8 +98,13 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
trace_ext4_sync_file_enter(file, datasync);
if (inode->i_sb->s_flags & MS_RDONLY)
if (inode->i_sb->s_flags & MS_RDONLY) {
/* Make sure that we read updated s_mount_flags value */
smp_rmb();
if (EXT4_SB(inode->i_sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
ret = -EROFS;
goto out;
}
if (!journal) {
ret = generic_file_fsync(file, start, end, datasync);

12
fs/ext4/super.c
View File

@ -399,6 +399,11 @@ static void ext4_handle_error(struct super_block *sb)
}
if (test_opt(sb, ERRORS_RO)) {
ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
/*
* Make sure updated value of ->s_mount_flags will be visible
* before ->s_flags update
*/
smp_wmb();
sb->s_flags |= MS_RDONLY;
}
if (test_opt(sb, ERRORS_PANIC))
@ -571,8 +576,13 @@ void __ext4_abort(struct super_block *sb, const char *function,
if ((sb->s_flags & MS_RDONLY) == 0) {
ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
sb->s_flags |= MS_RDONLY;
EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
/*
* Make sure updated value of ->s_mount_flags will be visible
* before ->s_flags update
*/
smp_wmb();
sb->s_flags |= MS_RDONLY;
if (EXT4_SB(sb)->s_journal)
jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
save_error_info(sb, function, line);