[PATCH 04/10] vfs: move ->create check in lookup_open() to before try_break_deleg()

[Jori Koolstra]

The i_op->create check in lookup_open() takes place after the
try_break_deleg() call. This does not match the order when doing a
regular file create via mknod(2). There the call order is:

	filename_mknodat()
	vfs_create()
	i_op->create check
	try_break_deleg()

Move the i_op->create check to before try_break_deleg() in
lookup_open().

Reviewed-by: NeilBrown <neil@xxxxxxxxxx>
Signed-off-by: Jori Koolstra <jkoolstra@xxxxxxxxx>
---
 fs/namei.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index a43e64717d11..aaba03954cd5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4520,16 +4520,17 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
 
 	/* Negative dentry, just create the file */
 	if (!dentry->d_inode && (open_flag & O_CREAT)) {
+		if (!dir_inode->i_op->create) {
+			error = -EACCES;
+			goto out_dput;
+		}
+
 		/* but break the directory lease first! */
 		error = try_break_deleg(dir_inode, LEASE_BREAK_DIR_CREATE, delegated_inode);
 		if (error)
 			goto out_dput;
 
 		audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE);
-		if (!dir_inode->i_op->create) {
-			error = -EACCES;
-			goto out_dput;
-		}
 
 		error = dir_inode->i_op->create(idmap, dir_inode, dentry,
 						mode, open_flag & O_EXCL);
-- 
2.55.0