[PATCH] erofs-utils: fsck: fix directory loop tracking

[PATCH] erofs-utils: fsck: fix directory loop tracking

[Vansh Choudhary]

Store the current directory nid in the recursion stack.

The loop check compares inode.nid against the entries already on the
stack, so pushing pnid there can miss self-referential directory loops
and report the wrong failure later.

Signed-off-by: Vansh Choudhary <ch@vnsh.in>
---
 fsck/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fsck/main.c b/fsck/main.c
index 16a354f..3530707 100644
--- a/fsck/main.c
+++ b/fsck/main.c
@@ -1022,7 +1022,7 @@ static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid)
 		for (i = 0; i < fsckcfg.dirstack.top; ++i)
 			if (inode.nid == fsckcfg.dirstack.dirs[i])
 				return -ELOOP;
-		fsckcfg.dirstack.dirs[fsckcfg.dirstack.top++] = pnid;
+		fsckcfg.dirstack.dirs[fsckcfg.dirstack.top++] = inode.nid;
 		ret = erofs_iterate_dir(&ctx, true);
 		--fsckcfg.dirstack.top;
 	}
-- 
2.51.0

Re: [PATCH] erofs-utils: fsck: fix directory loop tracking

[Nithurshen]

Hi Xiang,

This patch LGTM.

I tested the fix by compiling fsck with a debug trace and running
it against an image with a nested directory structure. I verified
that the recursion stack now correctly pushes the current directory's
NID (inode.nid) instead of inheriting the parent's NID, successfully
fixing the loop tracking logic.

Reviewed-by: Nithurshen <nithurshen.dev@gmail.com>
Tested-by: Nithurshen <nithurshen.dev@gmail.com>

Re: [PATCH] erofs-utils: fsck: fix directory loop tracking

[Gao Xiang]

On 2026/3/22 00:05, Nithurshen wrote:
> Hi Xiang,
> 
> This patch LGTM.
> 
> I tested the fix by compiling fsck with a debug trace and running
> it against an image with a nested directory structure. I verified
> that the recursion stack now correctly pushes the current directory's
> NID (inode.nid) instead of inheriting the parent's NID, successfully
> fixing the loop tracking logic.

Please help work on a testcase too, thanks.

> 
> Reviewed-by: Nithurshen <nithurshen.dev@gmail.com>
> Tested-by: Nithurshen <nithurshen.dev@gmail.com>