FAILED: patch "[PATCH] btrfs: tree-checker: reject BTRFS_FT_UNKNOWN dir type" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 31723c9542dba1681cc3720571fdf12ffe0eddd9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024081951-anyhow-fool-5756@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

31723c9542db ("btrfs: tree-checker: reject BTRFS_FT_UNKNOWN dir type")
94a48aef49f2 ("btrfs: extend btrfs_dir_item type to store encryption status")
e43eec81c516 ("btrfs: use struct qstr instead of name and namelen pairs")
07e81dc94474 ("btrfs: move accessor helpers into accessors.h")
ad1ac5012c2b ("btrfs: move btrfs_map_token to accessors")
55e5cfd36da5 ("btrfs: remove fs_info::pending_changes and related code")
7966a6b5959b ("btrfs: move fs_info::flags enum to fs.h")
fc97a410bd78 ("btrfs: move mount option definitions to fs.h")
0d3a9cf8c306 ("btrfs: convert incompat and compat flag test helpers to macros")
ec8eb376e271 ("btrfs: move BTRFS_FS_STATE* definitions and helpers to fs.h")
9b569ea0be6f ("btrfs: move the printk helpers out of ctree.h")
e118578a8df7 ("btrfs: move assert helpers out of ctree.h")
c7f13d428ea1 ("btrfs: move fs wide helpers out of ctree.h")
63a7cb130718 ("btrfs: auto enable discard=async when possible")
7a66eda351ba ("btrfs: move the btrfs_verity_descriptor_item defs up in ctree.h")
956504a331a6 ("btrfs: move trans_handle_cachep out of ctree.h")
f1e5c6185ca1 ("btrfs: move flush related definitions to space-info.h")
ed4c491a3db2 ("btrfs: move BTRFS_MAX_MIRRORS into scrub.c")
4300c58f8090 ("btrfs: move btrfs on-disk definitions out of ctree.h")
d60d956eb41f ("btrfs: remove unused set/clear_pending_info helpers")

thanks,

greg k-h

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

From 31723c9542dba1681cc3720571fdf12ffe0eddd9 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Mon, 12 Aug 2024 08:52:44 +0930
Subject: [PATCH] btrfs: tree-checker: reject BTRFS_FT_UNKNOWN dir type

[REPORT]
There is a bug report that kernel is rejecting a mismatching inode mode
and its dir item:

  [ 1881.553937] BTRFS critical (device dm-0): inode mode mismatch with
  dir: inode mode=040700 btrfs type=2 dir type=0

[CAUSE]
It looks like the inode mode is correct, while the dir item type
0 is BTRFS_FT_UNKNOWN, which should not be generated by btrfs at all.

This may be caused by a memory bit flip.

[ENHANCEMENT]
Although tree-checker is not able to do any cross-leaf verification, for
this particular case we can at least reject any dir type with
BTRFS_FT_UNKNOWN.

So here we enhance the dir type check from [0, BTRFS_FT_MAX), to
(0, BTRFS_FT_MAX).
Although the existing corruption can not be fixed just by such enhanced
checking, it should prevent the same 0x2->0x0 bitflip for dir type to
reach disk in the future.

Reported-by: Kota <nospam@kota.moe>
Link: https://lore.kernel.org/linux-btrfs/CACsxjPYnQF9ZF-0OhH16dAx50=BXXOcP74MxBc3BG+xae4vTTw@mail.gmail.com/
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index a825fa598e3c..6f1e2f2215d9 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -569,9 +569,10 @@ static int check_dir_item(struct extent_buffer *leaf,
 
 		/* dir type check */
 		dir_type = btrfs_dir_ftype(leaf, di);
-		if (unlikely(dir_type >= BTRFS_FT_MAX)) {
+		if (unlikely(dir_type <= BTRFS_FT_UNKNOWN ||
+			     dir_type >= BTRFS_FT_MAX)) {
 			dir_item_err(leaf, slot,
-			"invalid dir item type, have %u expect [0, %u)",
+			"invalid dir item type, have %u expect (0, %u)",
 				dir_type, BTRFS_FT_MAX);
 			return -EUCLEAN;
 		}