[PATCH v3 9/9] nfs: use d_duplicate()

[NeilBrown <neilb@ownmail.net>]

From: NeilBrown <neil@brown.name>

As preparation for d_alloc_parallel() being allowed without the
directory locked, use d_duplicate() to duplicate a dentry for silly
rename.

This results in an in-lookup name, so d_lookup_done() must be called.

Signed-off-by: NeilBrown <neil@brown.name>
---
 fs/nfs/dir.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 49283f533d6e..f02b1b068d93 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2802,11 +2802,12 @@ int nfs_rename(const struct mnt_idmap *idmap, struct inode *old_dir,
 			spin_unlock(&new_dentry->d_lock);
 
 			/* copy the target dentry's name */
-			dentry = d_alloc(new_dentry->d_parent,
-					 &new_dentry->d_name);
-			if (!dentry)
+			dentry = d_duplicate(new_dentry);
+			if (IS_ERR(dentry)) {
+				/* Keep using -ETXTBSY error */
+				dentry = NULL;
 				goto out;
-
+			}
 			/* silly-rename the existing target ... */
 			err = nfs_sillyrename(new_dir, new_dentry);
 			if (err)
@@ -2871,8 +2872,10 @@ int nfs_rename(const struct mnt_idmap *idmap, struct inode *old_dir,
 		nfs_dentry_handle_enoent(old_dentry);
 
 	/* new dentry created? */
-	if (dentry)
+	if (dentry) {
+		d_lookup_done(dentry);
 		dput(dentry);
+	}
 	return error;
 }
 EXPORT_SYMBOL_GPL(nfs_rename);
-- 
2.50.0.107.gf914562f5916.dirty