Btrfs: Invalidate dcache entry after creating snapshot and

We need to invalidate an existing dcache entry after creating a new
snapshot or subvolume, because a negative dache entry will stop us from
accessing the new snapshot or subvolume.

---
  ctree.h       |   23 +++++++++++++++++++++++
  inode.c       |    4 ++++
  transaction.c |    4 ++++
  3 files changed, 31 insertions(+)

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 1cb084efd6ed..f04684f7fea3 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -560,6 +560,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
         struct btrfs_root *root = pending->root;
         struct extent_buffer *tmp;
         int ret;
+        int namelen;
         u64 objectid;
 
         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
@@ -595,8 +596,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
          * insert the directory item
          */
         key.offset = (u64)-1;
+        namelen = strlen(pending->name);
         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
-                                    pending->name, strlen(pending->name),
+                                    pending->name, namelen,
                                     root->fs_info->sb->s_root->d_inode->i_ino,
                                     &key, BTRFS_FT_DIR);
 
@@ -606,6 +608,10 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
                              pending->name, strlen(pending->name), objectid,
                              root->fs_info->sb->s_root->d_inode->i_ino);
+
+        /* Invalidate existing dcache entry for new snapshot. */
+        btrfs_invalidate_dcache_root(root, pending->name, namelen);
+
 fail:
         kfree(new_root_item);
         return ret;