nfs: dont unhash target if renaming a directory

Move unhashing the target to after the check for existence and being a
non-directory.

If renaming a directory then the VFS already unhashes the target if it
is not busy.  If it's busy then acquiring more references during the
rename makes no difference.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 11d0c4c..76b7f53 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1579,15 +1579,6 @@ static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        struct dentry *dentry = NULL, *rehash = NULL;
        int error = -EBUSY;
 
-       /*
-        * To prevent any new references to the target during the rename,
-        * we unhash the dentry in advance.
-        */
-       if (!d_unhashed(new_dentry)) {
-               d_drop(new_dentry);
-               rehash = new_dentry;
-       }
-
        dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
                 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
                 new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
@@ -1599,25 +1590,36 @@ static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
         * silly-rename succeeds, the copied dentry is hashed and becomes
         * the new target.
         */
-       if (new_inode && !S_ISDIR(new_inode->i_mode) &&
-           atomic_read(&new_dentry->d_count) > 2) {
-               int err;
-               /* copy the target dentry's name */
-               dentry = d_alloc(new_dentry->d_parent,
-                                &new_dentry->d_name);
-               if (!dentry)
-                       goto out;
+       if (new_inode && !S_ISDIR(new_inode->i_mode)) {
+               /*
+                * To prevent any new references to the target during the
+                * rename, we unhash the dentry in advance.
+                */
+               if (!d_unhashed(new_dentry)) {
+                       d_drop(new_dentry);
+                       rehash = new_dentry;
+               }
 
-               /* silly-rename the existing target ... */
-               err = nfs_sillyrename(new_dir, new_dentry);
-               if (!err) {
-                       new_dentry = rehash = dentry;
-                       new_inode = NULL;
-                       /* instantiate the replacement target */
-                       d_instantiate(new_dentry, NULL);
-               } else if (atomic_read(&new_dentry->d_count) > 1)
-                       /* dentry still busy? */
-                       goto out;
+               if (atomic_read(&new_dentry->d_count) > 2) {
+                       int err;
+
+                       /* copy the target dentry's name */
+                       dentry = d_alloc(new_dentry->d_parent,
+                                        &new_dentry->d_name);
+                       if (!dentry)
+                               goto out;
+
+                       /* silly-rename the existing target ... */
+                       err = nfs_sillyrename(new_dir, new_dentry);
+                       if (!err) {
+                               new_dentry = rehash = dentry;
+                               new_inode = NULL;
+                               /* instantiate the replacement target */
+                               d_instantiate(new_dentry, NULL);
+                       } else if (atomic_read(&new_dentry->d_count) > 1)
+                               /* dentry still busy? */
+                               goto out;
+               }
        }
 
        /*