[PATCH 4/4] filelock: WARN_ON_ONCE when ->fl_file and filp don't match
From: Jeff Layton <jlayton@kernel.org>
Date: 2022-11-11 19:36:47
Subsystem:
file locking (flock() and fcntl()/lockf()), filesystems (vfs and infrastructure), the rest · Maintainers:
Jeff Layton, Chuck Lever, Alexander Viro, Christian Brauner, Linus Torvalds
vfs_lock_file, vfs_test_lock and vfs_cancel_lock all take both a struct file argument and a file_lock. The file_lock has a fl_file field in it howevever and it _must_ match the file passed in. While most of the locks.c routines use the separately-passed file argument, some filesystems rely on fl_file being filled out correctly. I'm working on a patch series to remove the redundant argument from these routines, but for now, let's ensure that the callers always set this properly by issuing a WARN_ON_ONCE if they ever don't match. Cc: Chuck Lever <redacted> Cc: Trond Myklebust <redacted> Signed-off-by: Jeff Layton <jlayton@kernel.org> --- fs/locks.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/locks.c b/fs/locks.c
index 607f94a0e789..5876c8ff0edc 100644
--- a/fs/locks.c
+++ b/fs/locks.c@@ -2146,6 +2146,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) */ int vfs_test_lock(struct file *filp, struct file_lock *fl) { + WARN_ON_ONCE(filp != fl->fl_file); if (filp->f_op->lock) return filp->f_op->lock(filp, F_GETLK, fl); posix_test_lock(filp, fl);
@@ -2295,6 +2296,7 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock) */ int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf) { + WARN_ON_ONCE(filp != fl->fl_file); if (filp->f_op->lock) return filp->f_op->lock(filp, cmd, fl); else
@@ -2663,6 +2665,7 @@ void locks_remove_file(struct file *filp) */ int vfs_cancel_lock(struct file *filp, struct file_lock *fl) { + WARN_ON_ONCE(filp != fl->fl_file); if (filp->f_op->lock) return filp->f_op->lock(filp, F_CANCELLK, fl); return 0;
--
2.38.1