FAILED: patch "[PATCH] nilfs2: fix nilfs_empty_dir() misjudgment and long loop on" failed to apply to 6.6-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 7373a51e7998b508af7136530f3a997b286ce81c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024061335-elevating-tumble-532e@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

7373a51e7998 ("nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors")
09a46acb3697 ("nilfs2: return the mapped address from nilfs_get_page()")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7373a51e7998b508af7136530f3a997b286ce81c Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Date: Tue, 4 Jun 2024 22:42:55 +0900
Subject: [PATCH] nilfs2: fix nilfs_empty_dir() misjudgment and long loop on
 I/O errors

The error handling in nilfs_empty_dir() when a directory folio/page read
fails is incorrect, as in the old ext2 implementation, and if the
folio/page cannot be read or nilfs_check_folio() fails, it will falsely
determine the directory as empty and corrupt the file system.

In addition, since nilfs_empty_dir() does not immediately return on a
failed folio/page read, but continues to loop, this can cause a long loop
with I/O if i_size of the directory's inode is also corrupted, causing the
log writer thread to wait and hang, as reported by syzbot.

Fix these issues by making nilfs_empty_dir() immediately return a false
value (0) if it fails to get a directory folio/page.

Link: https://lkml.kernel.org/r/20240604134255.7165-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+c8166c541d3971bf6c87@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
index a002a44ff161..52e50b1b7f22 100644
--- a/fs/nilfs2/dir.c
+++ b/fs/nilfs2/dir.c
@@ -607,7 +607,7 @@ int nilfs_empty_dir(struct inode *inode)
 
 		kaddr = nilfs_get_folio(inode, i, &folio);
 		if (IS_ERR(kaddr))
-			continue;
+			return 0;
 
 		de = (struct nilfs_dir_entry *)kaddr;
 		kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);