[PATCH v4 6/9] nfs: don't d_drop() before d_splice_alias() in atomic_create.

[NeilBrown <neilb@ownmail.net>]

From: NeilBrown <neil@brown.name>

When atomic_create fails with -ENOENT we currently d_drop() the dentry
and then re-add it (d_splice_alias()) with a NULL inode.
This drop-and-re-add will not work with proposed locking changes.

As d_splice_alias() now supports hashed dentries, we don't need the
d_drop() until it is determined that some other error has occurred.

Acked-by: Anna Schumaker <anna.schumaker@hammerspace.com>
Signed-off-by: NeilBrown <neil@brown.name>
---
 fs/nfs/dir.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b29dc1260d91..b296d90c8e14 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2196,7 +2196,6 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		err = PTR_ERR(inode);
 		trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
 		put_nfs_open_context(ctx);
-		d_drop(dentry);
 		switch (err) {
 		case -ENOENT:
 			if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
@@ -2205,7 +2204,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 				dir_verifier = nfs_save_change_attribute(dir);
 			nfs_set_verifier(dentry, dir_verifier);
 			d_splice_alias(NULL, dentry);
-			break;
+			goto out;
 		case -EISDIR:
 		case -ENOTDIR:
 			if (open_flags & __O_REGULAR) {
@@ -2221,6 +2220,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		default:
 			break;
 		}
+		d_drop(dentry);
 		goto out;
 	}
 	file->f_mode |= FMODE_CAN_ODIRECT;
@@ -2254,7 +2254,8 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 			dput(res);
 			res = ERR_PTR(-EOPENSTALE);
 		}
-	}
+	} else
+		d_drop(dentry);
 	return finish_no_open(file, res);
 }
 EXPORT_SYMBOL_GPL(nfs_atomic_open);
-- 
2.50.0.107.gf914562f5916.dirty