From: Amir Goldstein <amir73il@gmail.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
"J . Bruce Fields" <bfields@redhat.com>
Subject: [PATCH] exportfs: fix handling of rename race in reconnect_one()
Date: Mon, 27 Jan 2020 00:08:00 +0200 [thread overview]
Message-ID: <20200126220800.32397-1-amir73il@gmail.com> (raw)
If a disconnected dentry gets looked up and renamed between the
call to exportfs_get_name() and lookup_one_len_unlocked(), and if also
lookup_one_len_unlocked() returns ERR_PTR(-ENOENT), maybe because old
parent was deleted, we return an error, although dentry may be connected.
Commit 909e22e05353 ("exportfs: fix 'passing zero to ERR_PTR()'
warning") changes this behavior from always returning success,
regardless if dentry was reconnected by somoe other task, to always
returning a failure.
Change the lookup error handling to match that of exportfs_get_name()
error handling and return success after getting -ENOENT and verifying
that some other task has connected the dentry for us.
Cc: Christoph Hellwig <hch@lst.de>
Cc: J. Bruce Fields <bfields@redhat.com>
Fixes: 909e22e05353 ("exportfs: fix 'passing zero to ERR_PTR()' warning")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
fs/exportfs/expfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 2dd55b172d57..25a09bacf9c1 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -149,6 +149,8 @@ static struct dentry *reconnect_one(struct vfsmount *mnt,
if (IS_ERR(tmp)) {
dprintk("%s: lookup failed: %d\n", __func__, PTR_ERR(tmp));
err = PTR_ERR(tmp);
+ if (err == -ENOENT)
+ goto out_reconnected;
goto out_err;
}
if (tmp != dentry) {
--
2.17.1
next reply other threads:[~2020-01-26 22:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-26 22:08 Amir Goldstein [this message]
2020-01-27 8:04 ` [PATCH] exportfs: fix handling of rename race in reconnect_one() Christoph Hellwig
2020-01-27 17:30 ` J. Bruce Fields
2020-01-27 18:38 ` Amir Goldstein
2020-01-27 21:17 ` J. Bruce Fields
2020-02-06 20:22 ` Amir Goldstein
2020-02-06 21:10 ` J. Bruce Fields
2020-02-06 21:45 ` Al Viro
2020-02-07 6:26 ` Amir Goldstein
2020-03-13 14:33 ` Amir Goldstein
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