btrfs: do an allocation earlier during snapshot creation

We can allocate pending_snapshot earlier and do not have to do cleanup
in case of failure.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 9 insertions, 11 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6e896415a734..fa25091e10ab 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -655,22 +655,20 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
                 return -EINVAL;
 
+        pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
+        if (!pending_snapshot)
+                return -ENOMEM;
+
         atomic_inc(&root->will_be_snapshoted);
         smp_mb__after_atomic();
         btrfs_wait_for_no_snapshoting_writes(root);
 
         ret = btrfs_start_delalloc_inodes(root, 0);
         if (ret)
-                goto out;
+                goto dec_and_free;
 
         btrfs_wait_ordered_extents(root, -1);
 
-        pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
-        if (!pending_snapshot) {
-                ret = -ENOMEM;
-                goto out;
-        }
-
         btrfs_init_block_rsv(&pending_snapshot->block_rsv,
                              BTRFS_BLOCK_RSV_TEMP);
         /*
@@ -686,7 +684,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
                                         &pending_snapshot->qgroup_reserved,
                                         false);
         if (ret)
-                goto free;
+                goto dec_and_free;
 
         pending_snapshot->dentry = dentry;
         pending_snapshot->root = root;
@@ -737,11 +735,11 @@ fail:
         btrfs_subvolume_release_metadata(BTRFS_I(dir)->root,
                                          &pending_snapshot->block_rsv,
                                          pending_snapshot->qgroup_reserved);
-free:
-        kfree(pending_snapshot);
-out:
+dec_and_free:
         if (atomic_dec_and_test(&root->will_be_snapshoted))
                 wake_up_atomic_t(&root->will_be_snapshoted);
+        kfree(pending_snapshot);
+
         return ret;
 }