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| author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-04-02 10:34:36 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-04-02 18:51:12 -0400 |
| commit | 75da98586af75eb80664714a67a9895bf0a5517e (patch) | |
| tree | ebc21354f2cb42468d73ed950efdc249415f4a36 /fs/nfs | |
| parent | 529af90576cfa44aa107e9876e2ebaa053983986 (diff) | |
| download | lwn-75da98586af75eb80664714a67a9895bf0a5517e.tar.gz lwn-75da98586af75eb80664714a67a9895bf0a5517e.zip | |
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')
| -rw-r--r-- | fs/nfs/namespace.c | 12 |
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) |