ceph: don't leak snap_rwsem in handle_cap_grant

When handle_cap_grant is called on an IMPORT op, then the snap_rwsem is
held and the function is expected to release it before returning. It
currently fails to do that in all cases which could lead to a deadlock.

Fixes: 6f05b30 ("ceph: reset i_requested_max_size if file write is not wanted")
Link: https://tracker.ceph.com/issues/55857
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luís Henriques <lhenriques@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -3578,24 +3578,23 @@ static void handle_cap_grant(struct inode *inode,
 			fill_inline = true;
 	}
 
-	if (ci->i_auth_cap == cap &&
-	    le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
-		if (newcaps & ~extra_info->issued)
-			wake = true;
+	if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
+		if (ci->i_auth_cap == cap) {
+			if (newcaps & ~extra_info->issued)
+				wake = true;
+
+			if (ci->i_requested_max_size > max_size ||
+			    !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) {
+				/* re-request max_size if necessary */
+				ci->i_requested_max_size = 0;
+				wake = true;
+			}
 
-		if (ci->i_requested_max_size > max_size ||
-		    !(le32_to_cpu(grant->wanted) & CEPH_CAP_ANY_FILE_WR)) {
-			/* re-request max_size if necessary */
-			ci->i_requested_max_size = 0;
-			wake = true;
+			ceph_kick_flushing_inode_caps(session, ci);
 		}
-
-		ceph_kick_flushing_inode_caps(session, ci);
-		spin_unlock(&ci->i_ceph_lock);
 		up_read(&session->s_mdsc->snap_rwsem);
-	} else {
-		spin_unlock(&ci->i_ceph_lock);
 	}
+	spin_unlock(&ci->i_ceph_lock);
 
 	if (fill_inline)
 		ceph_fill_inline_data(inode, NULL, extra_info->inline_data,