atomic_open(): massage the create_error logics a bit

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 36520fc..ed48178 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2855,33 +2855,30 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
         * Another problem is returing the "right" error value (e.g. for an
         * O_EXCL open we want to return EEXIST not EROFS).
         */
-       if (((open_flag & (O_CREAT | O_TRUNC)) ||
-           (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) {
-               if (!(open_flag & O_CREAT)) {
-                       /*
-                        * No O_CREATE -> atomicity not a requirement -> fall
-                        * back to lookup + open
-                        */
-                       goto no_open;
-               } else if (open_flag & (O_EXCL | O_TRUNC)) {
-                       /* Fall back and fail with the right error */
-                       create_error = -EROFS;
-                       goto no_open;
-               } else {
-                       /* No side effects, safe to clear O_CREAT */
-                       create_error = -EROFS;
-                       open_flag &= ~O_CREAT;
-               }
-       }
-
        if (open_flag & O_CREAT) {
-               error = may_o_create(&nd->path, dentry, mode);
-               if (error) {
-                       create_error = error;
-                       if (open_flag & O_EXCL)
+               if (unlikely(!got_write)) {
+                       create_error = -EROFS;
+                       if (open_flag & (O_EXCL | O_TRUNC)) {
+                               /* Fall back and fail with the right error */
                                goto no_open;
+                       }
+                       /* No side effects, safe to clear O_CREAT */
                        open_flag &= ~O_CREAT;
+               } else {
+                       create_error = may_o_create(&nd->path, dentry, mode);
+                       if (create_error) {
+                               if (open_flag & O_EXCL)
+                                       goto no_open;
+                               open_flag &= ~O_CREAT;
+                       }
                }
+       } else if ((open_flag & (O_TRUNC|O_WRONLY|O_RDWR)) &&
+                  unlikely(!got_write)) {
+               /*
+                * No O_CREATE -> atomicity not a requirement -> fall
+                * back to lookup + open
+                */
+               goto no_open;
        }
 
        if (nd->flags & LOOKUP_DIRECTORY)