get rid of useless dget_parent() in fs/btrfs/ioctl.c

both callers there have dentry->d_parent stabilized by the fact that
their caller had obtained dentry from lookup_one_len() and had not
dropped ->i_mutex on parent since then.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 12 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a3c4751e07db..622543309eb2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -323,7 +323,7 @@ static noinline int create_subvol(struct btrfs_root *root,
         struct btrfs_inode_item *inode_item;
         struct extent_buffer *leaf;
         struct btrfs_root *new_root;
-        struct dentry *parent = dget_parent(dentry);
+        struct dentry *parent = dentry->d_parent;
         struct inode *dir;
         int ret;
         int err;
@@ -332,10 +332,8 @@ static noinline int create_subvol(struct btrfs_root *root,
         u64 index = 0;
 
         ret = btrfs_find_free_objectid(root->fs_info->tree_root, &objectid);
-        if (ret) {
-                dput(parent);
+        if (ret)
                 return ret;
-        }
 
         dir = parent->d_inode;
 
@@ -346,10 +344,8 @@ static noinline int create_subvol(struct btrfs_root *root,
          * 2 - dir items
          */
         trans = btrfs_start_transaction(root, 6);
-        if (IS_ERR(trans)) {
-                dput(parent);
+        if (IS_ERR(trans))
                 return PTR_ERR(trans);
-        }
 
         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
                                       0, objectid, NULL, 0, 0, 0);
@@ -439,7 +435,6 @@ static noinline int create_subvol(struct btrfs_root *root,
 
         d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 fail:
-        dput(parent);
         if (async_transid) {
                 *async_transid = trans->transid;
                 err = btrfs_commit_transaction_async(trans, root, 1);
@@ -456,7 +451,6 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
                            bool readonly)
 {
         struct inode *inode;
-        struct dentry *parent;
         struct btrfs_pending_snapshot *pending_snapshot;
         struct btrfs_trans_handle *trans;
         int ret;
@@ -504,9 +498,7 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
         if (ret)
                 goto fail;
 
-        parent = dget_parent(dentry);
-        inode = btrfs_lookup_dentry(parent->d_inode, dentry);
-        dput(parent);
+        inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
         if (IS_ERR(inode)) {
                 ret = PTR_ERR(inode);
                 goto fail;