NFS: Add timeout to submounts

Make automounted partitions expire using the mark_mounts_for_expiry()
function. The timeout is controlled via a sysctl.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 47167ab64f5ba4595320118420125e4fe1968f9b..3eea556d8f59274abe631527b4aa1c05bcdf60a6 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -167,6 +167,7 @@ static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
        struct nfs_server *server;
        struct rpc_clnt *rpc;
 
+       shrink_submounts(vfsmnt, &nfs_automount_list);
        if (!(flags & MNT_FORCE))
                return;
        /* -EIO all pending I/O */
@@ -1943,6 +1944,7 @@ static void nfs_kill_super(struct super_block *s)
        nfs_free_iostats(server->io_stats);
        kfree(server->hostname);
        kfree(server);
+       nfs_release_automount_timer();
 }
 
 static struct file_system_type nfs_fs_type = {
@@ -2288,6 +2290,7 @@ static void nfs4_kill_super(struct super_block *sb)
        nfs_free_iostats(server->io_stats);
        kfree(server->hostname);
        kfree(server);
+       nfs_release_automount_timer();
 }
 
 static struct file_system_type nfs4_fs_type = {

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index a155505c36f13112ef32c34f04bac4a98f1e2379..e426516c1116cf829e3341e847bdc45f704e92a8 100644 (file)
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -18,6 +18,11 @@
 
 #define NFSDBG_FACILITY                NFSDBG_VFS
 
+LIST_HEAD(nfs_automount_list);
+static void nfs_expire_automounts(void *list);
+static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list);
+int nfs_mountpoint_expiry_timeout = 500 * HZ;
+
 /*
  * nfs_follow_mountpoint - handle crossing a mountpoint on the server
  * @dentry - dentry of mountpoint
@@ -59,7 +64,7 @@ static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
                goto out_err;
 
        mntget(mnt);
-       err = do_add_mount(mnt, nd, nd->mnt->mnt_flags, NULL);
+       err = do_add_mount(mnt, nd, nd->mnt->mnt_flags|MNT_SHRINKABLE, &nfs_automount_list);
        if (err < 0) {
                mntput(mnt);
                if (err == -EBUSY)
@@ -70,6 +75,7 @@ static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
        dput(nd->dentry);
        nd->mnt = mnt;
        nd->dentry = dget(mnt->mnt_root);
+       schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
 out:
        dprintk("%s: done, returned %d\n", __FUNCTION__, err);
        return ERR_PTR(err);
@@ -87,3 +93,20 @@ struct inode_operations nfs_mountpoint_inode_operations = {
        .follow_link    = nfs_follow_mountpoint,
        .getattr        = nfs_getattr,
 };
+
+static void nfs_expire_automounts(void *data)
+{
+       struct list_head *list = (struct list_head *)data;
+
+       mark_mounts_for_expiry(list);
+       if (!list_empty(list))
+               schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
+}
+
+void nfs_release_automount_timer(void)
+{
+       if (list_empty(&nfs_automount_list)) {
+               cancel_delayed_work(&nfs_automount_task);
+               flush_scheduled_work();
+       }
+}

diff --git a/fs/nfs/sysctl.c b/fs/nfs/sysctl.c
index 4c486eb867ca0655d2c671d1b8c5eebf050e01ac..db61e51bb154747a949e63788c7bdd3e9765ffd2 100644 (file)
--- a/fs/nfs/sysctl.c
+++ b/fs/nfs/sysctl.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/nfs4.h>
 #include <linux/nfs_idmap.h>
+#include <linux/nfs_fs.h>
 
 #include "callback.h"
 
@@ -46,6 +47,15 @@ static ctl_table nfs_cb_sysctls[] = {
                .strategy = &sysctl_jiffies,
        },
 #endif
+       {
+               .ctl_name       = CTL_UNNUMBERED,
+               .procname       = "nfs_mountpoint_timeout",
+               .data           = &nfs_mountpoint_expiry_timeout,
+               .maxlen         = sizeof(nfs_mountpoint_expiry_timeout),
+               .mode           = 0644,
+               .proc_handler   = &proc_dointvec_jiffies,
+               .strategy       = &sysctl_jiffies,
+       },
        { .ctl_name = 0 }
 };
 

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 0ce8704732c217e43b8d95ff6da926f2c76fa9b2..a34b3ee443f1b0499c251980d931d5647aeac21d 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -405,7 +405,10 @@ extern void nfs_unregister_sysctl(void);
 /*
  * linux/fs/nfs/namespace.c
  */
+extern struct list_head nfs_automount_list;
 extern struct inode_operations nfs_mountpoint_inode_operations;
+extern int nfs_mountpoint_expiry_timeout;
+extern void nfs_release_automount_timer(void);
 
 /*
  * linux/fs/nfs/unlink.c