[PATCH] NFS: update ctime for atime-only UTIME_NOW requests

[PATCH] NFS: update ctime for atime-only UTIME_NOW requests

[Avi Weiss]

When an NFS client holds a timestamp delegation, utimensat()
with atime set to UTIME_NOW and mtime set to UTIME_OMIT reaches
nfs_setattr() with ATTR_TIMES_SET but without ATTR_ATIME_SET.

There may be other paths that can reach here as well.

The delegated-atime fast path treats this as an implicit atime
update, clears ATTR_ATIME and returns success without updating
ctime.

Add check for ATTR_TIMES_SET along with ATTR_ATIME_SET (OR) so
explicit timestamp requests use the normal SETATTR path while
incidental atime updates can keep using the local shortcut.

Fixes: e12912d94137 ("NFSv4: Add support for delegated atime and mtime attributes")
Signed-off-by: Avi Weiss <thnkslprpt@gmail.com>
---
 fs/nfs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 3022454f7698..255d7369cb3c 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -740,7 +740,7 @@ nfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	} else if (nfs_have_delegated_atime(inode) &&
 		   attr->ia_valid & ATTR_ATIME &&
 		   !(attr->ia_valid & ATTR_MTIME)) {
-		if (!(attr->ia_valid & ATTR_ATIME_SET)) {
+		if (!(attr->ia_valid & (ATTR_ATIME_SET | ATTR_TIMES_SET))) {
 			nfs_update_delegated_atime(inode);
 			attr->ia_valid &= ~ATTR_ATIME;
 		}

base-commit: 32c52ec87d6245ee2d12ed5dd509e40062939b50
-- 
2.43.0