[RFC][PATCH v4 33/69] atomic_open(): return the right dentry in FMODE_OPENED case

Al Viro
2020-03-13T23:54:09Z

->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>
---
fs/namei.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/namei.c b/fs/namei.c
index 40d5f7abfa54..88f985aff4f8 100644
--- 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);
--
2.11.0