FAILED: patch "[PATCH] fcntl: refuse F_SET_RW_HINT on an immutable inode" failed to apply to 6.1-stable tree

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 <[email protected]>.

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 b0d1022b9bdb1e98aa7fb3244fdd50a58c61766c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026101224-scoring-lent-e33f@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From b0d1022b9bdb1e98aa7fb3244fdd50a58c61766c Mon Sep 17 00:00:00 2001
From: Christian Brauner <[email protected]>
Date: Fri, 2 Oct 2026 15:52:34 +0200
Subject: [PATCH] fcntl: refuse F_SET_RW_HINT on an immutable inode

An immutable inode is never written to so write hints are pointless. Refuse the hint on an immutable inode the way setattr(), fallocate() and etxattr() refuse their changes.

index c158f082f1da..9b71bc9d71d1 100644
@@ -372,6 +372,9 @@ static long fcntl_set_rw_hint(struct file *file, unsigned long arg)
 	u64 __user *argp = (u64 __user *)arg;
 	u64 hint;
 
+	/* nothing is ever written to it */
+	if (IS_IMMUTABLE(inode))
+		return -EPERM;
 	if (!inode_owner_or_capable(file_mnt_idmap(file), inode))
 		return -EPERM;
 

From: Christian Brauner <[email protected]>

[ Upstream commit b0d1022b9bdb1e98aa7fb3244fdd50a58c61766c ]

An immutable inode is never written to so write hints are pointless. Refuse the hint on an immutable inode the way setattr(), fallocate() and etxattr() refuse their changes.

---
 fs/fcntl.c | 3 +++
 1 file changed, 3 insertions(+)

index 1bde178e4aa2e..13ba6b47877b8 100644
@@ -290,6 +290,9 @@ static long fcntl_rw_hint(struct file *file, unsigned int cmd,
 			return -EFAULT;
 		return 0;
 	case F_SET_RW_HINT:
+		/* nothing is ever written to it */
+		if (IS_IMMUTABLE(inode))
+			return -EPERM;
 		if (copy_from_user(&hint, argp, sizeof(hint)))
 			return -EFAULT;
 		if (!rw_hint_valid(hint))

2.53.0