Commit 4418e141 authored by Dmitry Monakhov's avatar Dmitry Monakhov Committed by Theodore Ts'o
Browse files

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: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 06a407f1

fs/ext4/fsync.c

+6 −1
Original line number Diff line number Diff line
@@ -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);

fs/ext4/super.c

+11 −1
Original line number Diff line number Diff line
@@ -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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE