From: Christian Brauner <brauner@kernel.org>
To: linux-fsdevel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
linux-kernel@vger.kernel.org, Jeff Layton <jlayton@kernel.org>,
Jann Horn <jannh@google.com>, Neil Brown <neil@brown.name>,
Amir Goldstein <amir73il@gmail.com>,
"Christian Brauner (Amutable)" <brauner@kernel.org>,
stable@vger.kernel.org
Subject: [PATCH 03/21] fcntl: refuse F_SET_RW_HINT on an immutable inode
Date: Fri, 02 Oct 2026 15:52:34 +0200 [thread overview]
Message-ID: <20261002-work-mount-fixes-4-v1-3-dd44b89d44ce@kernel.org> (raw)
In-Reply-To: <20261002-work-mount-fixes-4-v1-0-dd44b89d44ce@kernel.org>
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.
Fixes: c75b1d9421f8 ("fs: add fcntl() interface for setting/getting write life time hints")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
fs/fcntl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/fcntl.c b/fs/fcntl.c
index c158f082f1da..9b71bc9d71d1 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -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;
--
2.53.0
next prev parent reply other threads:[~2026-10-02 13:53 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-02 13:52 [PATCH 00/21] mount: more bugfixes, trapped in the Black Lodge edition Christian Brauner
2026-10-02 13:52 ` [PATCH 01/21] namespace: unhash a dentry before detaching the mounts on it Christian Brauner
2026-10-02 13:52 ` [PATCH 02/21] namei: don't reveal overmounted entries in refwalk Christian Brauner
2026-10-02 13:52 ` Christian Brauner [this message]
2026-10-02 13:52 ` [PATCH 04/21] selftests/filesystems: check that an immutable inode takes no write hint Christian Brauner
2026-10-02 13:52 ` [PATCH 05/21] namespace: refuse an automount below a mount that is in no namespace Christian Brauner
2026-10-02 13:52 ` [PATCH 06/21] namespace: handle mount locking for automounts correctly Christian Brauner
2026-10-02 13:52 ` [PATCH 07/21] nullfs: don't update the access time Christian Brauner
2026-10-02 13:52 ` [PATCH 08/21] namespace: never expire a locked mount Christian Brauner
2026-10-02 13:52 ` [PATCH 09/21] namespace: keep the lock on a mount that a propagated copy is moved beneath Christian Brauner
2026-10-02 13:52 ` [PATCH 10/21] selftests/filesystems: check that a lock lands on the right mount and stays Christian Brauner
2026-10-02 13:52 ` [PATCH 11/21] selftests/filesystems: check the atime of the empty mount namespace root Christian Brauner
2026-10-02 13:52 ` [PATCH 12/21] selftests/filesystems: check that an automount below an overlay layer is refused Christian Brauner
2026-10-02 13:52 ` [PATCH 13/21] fhandle: decide the subtree check under mount_lock Christian Brauner
2026-10-02 13:52 ` [PATCH 14/21] namespace: keep the private nullfs instance in knullfs Christian Brauner
2026-10-02 13:52 ` [PATCH 15/21] namespace: nothing is mounted on or written through knullfs Christian Brauner
2026-10-02 13:52 ` [PATCH 16/21] fsnotify: let a filesystem refuse marks on its objects Christian Brauner
2026-10-02 14:26 ` Amir Goldstein
2026-10-02 13:52 ` [PATCH 17/21] nullfs: refuse file locks Christian Brauner
2026-10-02 13:52 ` [PATCH 18/21] nullfs: refuse leases and delegations Christian Brauner
2026-10-02 13:52 ` [PATCH 19/21] readdir: take no inode lock on an immutable directory Christian Brauner
2026-10-02 13:52 ` [PATCH 20/21] selftests/filesystems: add a helper that holds a readdir in a page fault Christian Brauner
2026-10-02 13:52 ` [PATCH 21/21] selftests/filesystems: check that reading the root of an empty mount namespace stalls nobody Christian Brauner
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