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authorTrond Myklebust <trond.myklebust@hammerspace.com>2020-04-02 10:34:36 -0400
committerTrond Myklebust <trond.myklebust@hammerspace.com>2020-04-02 18:51:12 -0400
commit75da98586af75eb80664714a67a9895bf0a5517e (patch)
treeebc21354f2cb42468d73ed950efdc249415f4a36 /fs/nfs/namespace.c
parent529af90576cfa44aa107e9876e2ebaa053983986 (diff)
downloadlinux-75da98586af75eb80664714a67a9895bf0a5517e.tar.bz2
NFS: finish_automount() requires us to hold 2 refs to the mount record
We must not return from nfs_d_automount() without holding 2 references to the mount record. Doing so, will trigger the BUG() in finish_automount(). Also ensure that we don't try to reschedule the automount timer with a negative or zero timeout value. Fixes: 22a1ae9a93fb ("NFS: If nfs_mountpoint_expiry_timeout < 0, do not expire submounts") Cc: stable@vger.kernel.org # v5.5+ Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs/namespace.c')
-rw-r--r--fs/nfs/namespace.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index da67820462f2..fe19ae280262 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -145,6 +145,7 @@ struct vfsmount *nfs_d_automount(struct path *path)
struct vfsmount *mnt = ERR_PTR(-ENOMEM);
struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
struct nfs_client *client = server->nfs_client;
+ int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout);
int ret;
if (IS_ROOT(path->dentry))
@@ -190,12 +191,12 @@ struct vfsmount *nfs_d_automount(struct path *path)
if (IS_ERR(mnt))
goto out_fc;
- if (nfs_mountpoint_expiry_timeout < 0)
+ mntget(mnt); /* prevent immediate expiration */
+ if (timeout <= 0)
goto out_fc;
- mntget(mnt); /* prevent immediate expiration */
mnt_set_expiry(mnt, &nfs_automount_list);
- schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
+ schedule_delayed_work(&nfs_automount_task, timeout);
out_fc:
put_fs_context(fc);
@@ -233,10 +234,11 @@ const struct inode_operations nfs_referral_inode_operations = {
static void nfs_expire_automounts(struct work_struct *work)
{
struct list_head *list = &nfs_automount_list;
+ int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout);
mark_mounts_for_expiry(list);
- if (!list_empty(list))
- schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
+ if (!list_empty(list) && timeout > 0)
+ schedule_delayed_work(&nfs_automount_task, timeout);
}
void nfs_release_automount_timer(void)