linux-kernel - [PATCH] afs: Fix the nlink handling of dir-over-dir rename

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Date:   Thu, 27 May 2021 11:24:33 +0100
From:   David Howells <dhowells@...hat.com>
To:     torvalds@...ux-foundation.org
Cc:     Marc Dionne <marc.dionne@...istor.com>,
        linux-afs@...ts.infradead.org, dhowells@...hat.com,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] afs: Fix the nlink handling of dir-over-dir rename

Fix rename of one directory over another such that the nlink on the deleted
directory is cleared to 0 rather than being decremented to 1.

This was causing the generic/035 xfstest to fail.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@...hat.com>
Reviewed-by: Marc Dionne <marc.dionne@...istor.com>
cc: linux-afs@...ts.infradead.org
Link: https://lore.kernel.org/r/162194384460.3999479.7605572278074191079.stgit@warthog.procyon.org.uk/ # v1
---

 fs/afs/dir.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 9fbe5a5ec9bd..78719f2f567e 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1919,7 +1919,9 @@ static void afs_rename_edit_dir(struct afs_operation *op)
 	new_inode = d_inode(new_dentry);
 	if (new_inode) {
 		spin_lock(&new_inode->i_lock);
-		if (new_inode->i_nlink > 0)
+		if (S_ISDIR(new_inode->i_mode))
+			clear_nlink(new_inode);
+		else if (new_inode->i_nlink > 0)
 			drop_nlink(new_inode);
 		spin_unlock(&new_inode->i_lock);
 	}