FAILED: patch "[PATCH] ext4: drop extent cache when splitting extent fails" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 79b592e8f1b435796cbc2722190368e3e8ffd7a1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026022429-decline-tucking-14ad@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 79b592e8f1b435796cbc2722190368e3e8ffd7a1 Mon Sep 17 00:00:00 2001
From: Zhang Yi <yi.zhang@huawei.com>
Date: Sat, 29 Nov 2025 18:32:39 +0800
Subject: [PATCH] ext4: drop extent cache when splitting extent fails

When the split extent fails, we might leave some extents still being
processed and return an error directly, which will result in stale
extent entries remaining in the extent status tree. So drop all of the
remaining potentially stale extents if the splitting fails.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Cc: stable@kernel.org
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251129103247.686136-8-yi.zhang@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 1094e4923451..945995d68c4d 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3267,7 +3267,7 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
 
 	err = PTR_ERR(path);
 	if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
-		return path;
+		goto out_path;
 
 	/*
 	 * Get a new path to try to zeroout or fix the extent length.
@@ -3281,7 +3281,7 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
 	if (IS_ERR(path)) {
 		EXT4_ERROR_INODE(inode, "Failed split extent on %u, err %ld",
 				 split, PTR_ERR(path));
-		return path;
+		goto out_path;
 	}
 	depth = ext_depth(inode);
 	ex = path[depth].p_ext;
@@ -3358,6 +3358,10 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle,
 		ext4_free_ext_path(path);
 		path = ERR_PTR(err);
 	}
+out_path:
+	if (IS_ERR(path))
+		/* Remove all remaining potentially stale extents. */
+		ext4_es_remove_extent(inode, ee_block, ee_len);
 	ext4_ext_show_leaf(inode, path);
 	return path;
 }