[f2fs-dev] [PATCH] f2fs: fix to avoid dirent corruption

[f2fs-dev] [PATCH] f2fs: fix to avoid dirent corruption

[Chao Yu]

As Al reported in link[1]:

f2fs_rename()
...
	if (old_dir != new_dir && !whiteout)
		f2fs_set_link(old_inode, old_dir_entry,
					old_dir_page, new_dir);
	else
		f2fs_put_page(old_dir_page, 0);

You want correct inumber in the ".." link.  And cross-directory
rename does move the source to new parent, even if you'd been asked
to leave a whiteout in the old place.

[1] https://lore.kernel.org/all/20231017055040.GN800259@ZenIV/

With below testcase, it may cause dirent corruption, due to it missed
to call f2fs_set_link() to update ".." link to new directory.
- mkdir -p dir/foo
- renameat2 -w dir/foo bar

[ASSERT] (__chk_dots_dentries:1421)  --> Bad inode number[0x4] for '..', parent parent ino is [0x3]
[FSCK] other corrupted bugs                           [Fail]

Fixes: 7e01e7ad746b ("f2fs: support RENAME_WHITEOUT")
Cc: Jan Kara <jack@suse.cz>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 3b1793cfb002..ede6afb81762 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1105,7 +1105,7 @@ static int f2fs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	}
 
 	if (old_dir_entry) {
-		if (old_dir != new_dir && !whiteout)
+		if (old_dir != new_dir)
 			f2fs_set_link(old_inode, old_dir_entry,
 						old_dir_page, new_dir);
 		else
-- 
2.40.1



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Re: [f2fs-dev] [PATCH] f2fs: fix to avoid dirent corruption

[Jan Kara]

On Tue 28-11-23 17:25:16, Chao Yu wrote:
> As Al reported in link[1]:
> 
> f2fs_rename()
> ...
> 	if (old_dir != new_dir && !whiteout)
> 		f2fs_set_link(old_inode, old_dir_entry,
> 					old_dir_page, new_dir);
> 	else
> 		f2fs_put_page(old_dir_page, 0);
> 
> You want correct inumber in the ".." link.  And cross-directory
> rename does move the source to new parent, even if you'd been asked
> to leave a whiteout in the old place.
> 
> [1] https://lore.kernel.org/all/20231017055040.GN800259@ZenIV/
> 
> With below testcase, it may cause dirent corruption, due to it missed
> to call f2fs_set_link() to update ".." link to new directory.
> - mkdir -p dir/foo
> - renameat2 -w dir/foo bar
> 
> [ASSERT] (__chk_dots_dentries:1421)  --> Bad inode number[0x4] for '..', parent parent ino is [0x3]
> [FSCK] other corrupted bugs                           [Fail]
> 
> Fixes: 7e01e7ad746b ("f2fs: support RENAME_WHITEOUT")
> Cc: Jan Kara <jack@suse.cz>
> Reported-by: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Chao Yu <chao@kernel.org>

Thanks for fixing this! Makes sense to me so feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/f2fs/namei.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index 3b1793cfb002..ede6afb81762 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -1105,7 +1105,7 @@ static int f2fs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
>  	}
>  
>  	if (old_dir_entry) {
> -		if (old_dir != new_dir && !whiteout)
> +		if (old_dir != new_dir)
>  			f2fs_set_link(old_inode, old_dir_entry,
>  						old_dir_page, new_dir);
>  		else
> -- 
> 2.40.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR


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Re: [f2fs-dev] [PATCH] f2fs: fix to avoid dirent corruption

[patchwork-bot+f2fs]

Hello:

This patch was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:

On Tue, 28 Nov 2023 17:25:16 +0800 you wrote:
> As Al reported in link[1]:
> 
> f2fs_rename()
> ...
> 	if (old_dir != new_dir && !whiteout)
> 		f2fs_set_link(old_inode, old_dir_entry,
> 					old_dir_page, new_dir);
> 	else
> 		f2fs_put_page(old_dir_page, 0);
> 
> [...]

Here is the summary with links:
  - [f2fs-dev] f2fs: fix to avoid dirent corruption
    https://git.kernel.org/jaegeuk/f2fs/c/53edb549565f

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html




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