1 files changed, 10 insertions, 0 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 657d83ca9dea..d4608ab72b79 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -710,6 +710,16 @@ static noinline int btrfs_mksubvol(struct path *parent,
         if (error)
                 goto out_dput;
 
+        /*
+         * even if this name doesn't exist, we may get hash collisions.
+         * check for them now when we can safely fail
+         */
+        error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
+                                               dir->i_ino, name,
+                                               namelen);
+        if (error)
+                goto out_dput;
+
         down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 
         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)