[PATCH v5 25/42] utimes: handle idmapped mounts

[Christian Brauner]

Enable the vfs_utimes() helper to handle idmapped mounts by passing down
the mount's user namespace. If the initial user namespace is passed
nothing changes so non-idmapped mounts will see identical behavior as
before.

Cc: Christoph Hellwig <hch at lst.de>
Cc: David Howells <dhowells at redhat.com>
Cc: Al Viro <viro at zeniv.linux.org.uk>
Cc: linux-fsdevel at vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
/* v2 */
unchanged

/* v3 */
unchanged

/* v4 */
- Serge Hallyn <serge at hallyn.com>:
  - Use "mnt_userns" to refer to a vfsmount's userns everywhere to make
    terminology consistent.

/* v5 */
base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837
---
 fs/utimes.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/utimes.c b/fs/utimes.c
index 1a4130bee157..33fa753bab3a 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -22,6 +22,7 @@ int vfs_utimes(const struct path *path, struct timespec64 *times)
 	struct iattr newattrs;
 	struct inode *inode = path->dentry->d_inode;
 	struct inode *delegated_inode = NULL;
+	struct user_namespace *mnt_userns;
 
 	if (times) {
 		if (!nsec_valid(times[0].tv_nsec) ||
@@ -61,8 +62,9 @@ int vfs_utimes(const struct path *path, struct timespec64 *times)
 		newattrs.ia_valid |= ATTR_TOUCH;
 	}
 retry_deleg:
+	mnt_userns = mnt_user_ns(path->mnt);
 	inode_lock(inode);
-	error = notify_change(&init_user_ns, path->dentry, &newattrs, &delegated_inode);
+	error = notify_change(mnt_userns, path->dentry, &newattrs, &delegated_inode);
 	inode_unlock(inode);
 	if (delegated_inode) {
 		error = break_deleg_wait(&delegated_inode);
-- 
2.30.0