2022-06-15 08:47:50

by yebin (H)

Subject: [PATCH -next] ext2: fix fs corruption when trying to remove a non-empty directory with IO error

We got issue as follows:
[home]# mount /dev/sdd test
[home]# cd test
[test]# ls
dir1 lost+found
[test]# rmdir dir1
ext2_empty_dir: inject fault
[test]# ls
lost+found
[test]# cd ..
[home]# umount test
[home]# fsck.ext2 -fn /dev/sdd
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Inode 4065, i_size is 0, should be 1024. Fix? no

Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Unconnected directory inode 4065 (/???)
Connect to /lost+found? no

'..' in ... (4065) is / (2), should be <The NULL inode> (0).
Fix? no

Pass 4: Checking reference counts
Inode 2 ref count is 3, should be 4. Fix? no

Inode 4065 ref count is 2, should be 3. Fix? no

Pass 5: Checking group summary information

/dev/sdd: ********** WARNING: Filesystem still has errors **********

/dev/sdd: 14/128016 files (0.0% non-contiguous), 18477/512000 blocks

Reason is same with commit 7aab5c84a0f6. We can't assume directory
is empty when read directory entry failed.

Signed-off-by: Ye Bin <[email protected]>
---
fs/ext2/dir.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 3bd5772b401b..8f597753ac12 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -672,17 +672,14 @@ int ext2_empty_dir (struct inode * inode)
void *page_addr = NULL;
struct page *page = NULL;
unsigned long i, npages = dir_pages(inode);
- int dir_has_error = 0;

for (i = 0; i < npages; i++) {
char *kaddr;
ext2_dirent * de;
- page = ext2_get_page(inode, i, dir_has_error, &page_addr);
+ page = ext2_get_page(inode, i, 0, &page_addr);

- if (IS_ERR(page)) {
- dir_has_error = 1;
- continue;
- }
+ if (IS_ERR(page))
+ goto not_empty;

kaddr = page_addr;
de = (ext2_dirent *)kaddr;
--
2.31.1

2022-06-15 17:21:12

by Jan Kara

Subject: Re: [PATCH -next] ext2: fix fs corruption when trying to remove a non-empty directory with IO error

On Wed 15-06-22 17:00:10, Ye Bin wrote:
> We got issue as follows:
> [home]# mount /dev/sdd test
> [home]# cd test
> [test]# ls
> dir1 lost+found
> [test]# rmdir dir1
> ext2_empty_dir: inject fault
> [test]# ls
> lost+found
> [test]# cd ..
> [home]# umount test
> [home]# fsck.ext2 -fn /dev/sdd
> e2fsck 1.42.9 (28-Dec-2013)
> Pass 1: Checking inodes, blocks, and sizes
> Inode 4065, i_size is 0, should be 1024. Fix? no
>
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Unconnected directory inode 4065 (/???)
> Connect to /lost+found? no
>
> '..' in ... (4065) is / (2), should be <The NULL inode> (0).
> Fix? no
>
> Pass 4: Checking reference counts
> Inode 2 ref count is 3, should be 4. Fix? no
>
> Inode 4065 ref count is 2, should be 3. Fix? no
>
> Pass 5: Checking group summary information
>
> /dev/sdd: ********** WARNING: Filesystem still has errors **********
>
> /dev/sdd: 14/128016 files (0.0% non-contiguous), 18477/512000 blocks
>
> Reason is same with commit 7aab5c84a0f6. We can't assume directory
> is empty when read directory entry failed.
>
> Signed-off-by: Ye Bin <[email protected]>

Honestly, I'm not very much concerned about corrupting the filesystem more
when we've got EIO for metadata but OK, probably what you propose is a
saner choice. I've added the patch to my tree.

Honza

> ---
> fs/ext2/dir.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
> index 3bd5772b401b..8f597753ac12 100644
> --- a/fs/ext2/dir.c
> +++ b/fs/ext2/dir.c
> @@ -672,17 +672,14 @@ int ext2_empty_dir (struct inode * inode)
> void *page_addr = NULL;
> struct page *page = NULL;
> unsigned long i, npages = dir_pages(inode);
> - int dir_has_error = 0;
>
> for (i = 0; i < npages; i++) {
> char *kaddr;
> ext2_dirent * de;
> - page = ext2_get_page(inode, i, dir_has_error, &page_addr);
> + page = ext2_get_page(inode, i, 0, &page_addr);
>
> - if (IS_ERR(page)) {
> - dir_has_error = 1;
> - continue;
> - }
> + if (IS_ERR(page))
> + goto not_empty;
>
> kaddr = page_addr;
> de = (ext2_dirent *)kaddr;
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR