ceph: fix error handling in ceph_atomic_open and ceph_lookup

Commit aa60cfc3 broke the error handling in these functions such
that they don't handle non-ENOENT errors from ceph_mdsc_do_request
properly.

Move the checking of -ENOENT out of ceph_handle_snapdir and into the
callers, and if we get a different error, return it immediately.

Fixes: aa60cfc3 ("ceph: don't use d_add in ceph_handle_snapdir")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/dir.c

@@ -668,14 +668,13 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
  * Handle lookups for the hidden .snap directory.
  */
 struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
-				   struct dentry *dentry, int err)
+				   struct dentry *dentry)
 {
 	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
 	struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
 
 	/* .snap dir? */
-	if (err == -ENOENT &&
-	    ceph_snap(parent) == CEPH_NOSNAP &&
+	if (ceph_snap(parent) == CEPH_NOSNAP &&
 	    strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) {
 		struct dentry *res;
 		struct inode *inode = ceph_get_snapdir(parent);
@@ -742,7 +741,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
 	struct ceph_mds_request *req;
-	struct dentry *res;
 	int op;
 	int mask;
 	int err;
@@ -793,12 +791,16 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
 	req->r_parent = dir;
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
-	res = ceph_handle_snapdir(req, dentry, err);
-	if (IS_ERR(res)) {
-		err = PTR_ERR(res);
-	} else {
-		dentry = res;
-		err = 0;
+	if (err == -ENOENT) {
+		struct dentry *res;
+
+		res = ceph_handle_snapdir(req, dentry);
+		if (IS_ERR(res)) {
+			err = PTR_ERR(res);
+		} else {
+			dentry = res;
+			err = 0;
+		}
 	}
 	dentry = ceph_finish_lookup(req, dentry, err);
 	ceph_mdsc_put_request(req);  /* will dput(dentry) */

fs/ceph/file.c

@@ -742,14 +742,16 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 	err = ceph_mdsc_do_request(mdsc,
 				   (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
 				   req);
-	dentry = ceph_handle_snapdir(req, dentry, err);
-	if (IS_ERR(dentry)) {
-		err = PTR_ERR(dentry);
-		goto out_req;
+	if (err == -ENOENT) {
+		dentry = ceph_handle_snapdir(req, dentry);
+		if (IS_ERR(dentry)) {
+			err = PTR_ERR(dentry);
+			goto out_req;
+		}
+		err = 0;
 	}
-	err = 0;
 
-	if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
+	if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
 		err = ceph_handle_notrace_create(dir, dentry);
 
 	if (d_in_lookup(dentry)) {

fs/ceph/super.h

@@ -1218,7 +1218,7 @@ extern const struct dentry_operations ceph_dentry_ops;
 extern loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order);
 extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry);
 extern struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req,
-			       struct dentry *dentry, int err);
+			       struct dentry *dentry);
 extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
 					 struct dentry *dentry, int err);