[PATCH 2/9] 9p: simplify v9fs_vfs_atomic_open()

[Al Viro <viro@xxxxxxxxxxxxxxxxxx>]

if v9fs_vfs_lookup() returns a preexisting alias, it is guaranteed to be
positive.  IOW, in that case we will immediately return finish_no_open(),
leaving only the case res == NULL past that point.

Reviewed-by: NeilBrown <neil@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
 fs/9p/vfs_inode.c | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 399d455d50d6..d0c77ec31b1d 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -768,22 +768,18 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	struct v9fs_inode __maybe_unused *v9inode;
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *fid;
-	struct dentry *res = NULL;
 	struct inode *inode;
 	int p9_omode;
 
 	if (d_in_lookup(dentry)) {
-		res = v9fs_vfs_lookup(dir, dentry, 0);
-		if (IS_ERR(res))
-			return PTR_ERR(res);
-
-		if (res)
-			dentry = res;
+		struct dentry *res = v9fs_vfs_lookup(dir, dentry, 0);
+		if (res || d_really_is_positive(dentry))
+			return finish_no_open(file, res);
 	}
 
 	/* Only creates */
-	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
-		return finish_no_open(file, res);
+	if (!(flags & O_CREAT))
+		return finish_no_open(file, NULL);
 
 	v9ses = v9fs_inode2v9ses(dir);
 	perm = unixmode2p9mode(v9ses, mode);
@@ -795,17 +791,17 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 			"write-only file with writeback enabled, creating w/ O_RDWR\n");
 	}
 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
-	if (IS_ERR(fid)) {
-		err = PTR_ERR(fid);
-		goto error;
-	}
+	if (IS_ERR(fid))
+		return PTR_ERR(fid);
 
 	v9fs_invalidate_inode_attr(dir);
 	inode = d_inode(dentry);
 	v9inode = V9FS_I(inode);
 	err = finish_open(file, dentry, generic_file_open);
-	if (err)
-		goto error;
+	if (unlikely(err)) {
+		p9_fid_put(fid);
+		return err;
+	}
 
 	file->private_data = fid;
 #ifdef CONFIG_9P_FSCACHE
@@ -818,13 +814,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	v9fs_open_fid_add(inode, &fid);
 
 	file->f_mode |= FMODE_CREATED;
-out:
-	dput(res);
-	return err;
-
-error:
-	p9_fid_put(fid);
-	goto out;
+	return 0;
 }
 
 /**
-- 
2.47.3