atomic_open(): return the right dentry in FMODE_OPENED case

->atomic_open() might have used a different alias than the one we'd
passed to it; in "not opened" case we take care of that, in "opened"
one we don't.  Currently we don't care downstream of "opened" case
which alias to return; however, that will change shortly when we
get to unifying may_open() calls.

It's not hard to get right in all cases, anyway.

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

diff --git a/fs/namei.c b/fs/namei.c
index 40d5f7a..88f985a 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2949,11 +2949,15 @@ static struct dentry *atomic_open(struct nameidata *nd, struct dentry *dentry,
        d_lookup_done(dentry);
        if (!error) {
                if (file->f_mode & FMODE_OPENED) {
+                       int acc_mode = op->acc_mode;
+                       if (unlikely(dentry != file->f_path.dentry)) {
+                               dput(dentry);
+                               dentry = dget(file->f_path.dentry);
+                       }
                        /*
                         * We didn't have the inode before the open, so check open
                         * permission here.
                         */
-                       int acc_mode = op->acc_mode;
                        if (file->f_mode & FMODE_CREATED) {
                                WARN_ON(!(open_flag & O_CREAT));
                                fsnotify_create(dir, dentry);