2020-09-28 02:06:48

by zhangxiaoxu (A)

Subject: [PATCH v3] ext4: Fix bdev write error check failed when mount fs with ro

Consider a situation when a filesystem was uncleanly shutdown and the
orphan list is not empty and a read-only mount is attempted. The orphan
list cleanup during mount will fail with:

ext4_check_bdev_write_error:193: comm mount: Error while async write back metadata

This happens because sbi->s_bdev_wb_err is not initialized when mounting
the filesystem in read only mode and so ext4_check_bdev_write_error()
falsely triggers.

Initialize sbi->s_bdev_wb_err unconditionally to avoid this problem.

Fixes: bc71726c7257 ("ext4: abort the filesystem if failed to async write metadata buffer")
Signed-off-by: Zhang Xiaoxu <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
---
fs/ext4/super.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ea425b49b345..0303e6e17190 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4814,9 +4814,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
* used to detect the metadata async write error.
*/
spin_lock_init(&sbi->s_bdev_wb_lock);
- if (!sb_rdonly(sb))
- errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
- &sbi->s_bdev_wb_err);
+ errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
+ &sbi->s_bdev_wb_err);
sb->s_bdev->bd_super = sb;
EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
ext4_orphan_cleanup(sb, es);
@@ -5707,14 +5706,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
goto restore_opts;
}

- /*
- * Update the original bdev mapping's wb_err value
- * which could be used to detect the metadata async
- * write error.
- */
- errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
- &sbi->s_bdev_wb_err);
-
/*
* Mounting a RDONLY partition read-write, so reread
* and store the current valid flag. (It may have
--
2.25.4

2020-10-03 05:10:13

by Theodore Ts'o

Subject: Re: [PATCH v3] ext4: Fix bdev write error check failed when mount fs with ro

On Sun, Sep 27, 2020 at 10:05:56PM -0400, Zhang Xiaoxu wrote:
> Consider a situation when a filesystem was uncleanly shutdown and the
> orphan list is not empty and a read-only mount is attempted. The orphan
> list cleanup during mount will fail with:
>
> ext4_check_bdev_write_error:193: comm mount: Error while async write back metadata
>
> This happens because sbi->s_bdev_wb_err is not initialized when mounting
> the filesystem in read only mode and so ext4_check_bdev_write_error()
> falsely triggers.
>
> Initialize sbi->s_bdev_wb_err unconditionally to avoid this problem.
>
> Fixes: bc71726c7257 ("ext4: abort the filesystem if failed to async write metadata buffer")
> Signed-off-by: Zhang Xiaoxu <[email protected]>
> Reviewed-by: Jan Kara <[email protected]>

Applied, thanks.

- Ted