ceph: unify inode i_ctime update

Current __ceph_setattr() can set inode's i_ctime to current_time(),
req->r_stamp or attr->ia_ctime. These time stamps may have minor
differences. It may cause potential problem.
Signed-off-by: N"Yan, Zheng" <zyan@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

fs/ceph/acl.c

@@ -131,6 +131,7 @@ int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	}
 
 	if (new_mode != old_mode) {
+		newattrs.ia_ctime = current_time(inode);
 		newattrs.ia_mode = new_mode;
 		newattrs.ia_valid = ATTR_MODE;
 		ret = __ceph_setattr(inode, &newattrs);

fs/ceph/inode.c

@@ -2022,7 +2022,6 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
 		    attr->ia_size > inode->i_size) {
 			i_size_write(inode, attr->ia_size);
 			inode->i_blocks = calc_inode_blocks(attr->ia_size);
-			inode->i_ctime = attr->ia_ctime;
 			ci->i_reported_size = attr->ia_size;
 			dirtied |= CEPH_CAP_FILE_EXCL;
 		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
@@ -2044,7 +2043,6 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
 		     inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
 		     attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec,
 		     only ? "ctime only" : "ignored");
-		inode->i_ctime = attr->ia_ctime;
 		if (only) {
 			/*
 			 * if kernel wants to dirty ctime but nothing else,
@@ -2067,7 +2065,7 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
 	if (dirtied) {
 		inode_dirty_flags = __ceph_mark_dirty_caps(ci, dirtied,
 							   &prealloc_cf);
-		inode->i_ctime = current_time(inode);
+		inode->i_ctime = attr->ia_ctime;
 	}
 
 	release &= issued;
@@ -2085,6 +2083,7 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
 		req->r_inode_drop = release;
 		req->r_args.setattr.mask = cpu_to_le32(mask);
 		req->r_num_caps = 1;
+		req->r_stamp = attr->ia_ctime;
 		err = ceph_mdsc_do_request(mdsc, NULL, req);
 	}
 	dout("setattr %p result=%d (%s locally, %d remote)\n", inode, err,