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55a97593 TM |
1 | /* |
2 | * linux/fs/nfs/namespace.c | |
3 | * | |
4 | * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> | |
5 | * | |
6 | * NFS namespace | |
7 | */ | |
8 | ||
9 | #include <linux/config.h> | |
10 | ||
11 | #include <linux/dcache.h> | |
12 | #include <linux/mount.h> | |
13 | #include <linux/namei.h> | |
14 | #include <linux/nfs_fs.h> | |
15 | #include <linux/string.h> | |
16 | #include <linux/sunrpc/clnt.h> | |
17 | #include <linux/vfs.h> | |
18 | ||
19 | #define NFSDBG_FACILITY NFSDBG_VFS | |
20 | ||
51d8fa6a TM |
21 | LIST_HEAD(nfs_automount_list); |
22 | static void nfs_expire_automounts(void *list); | |
23 | static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list); | |
24 | int nfs_mountpoint_expiry_timeout = 500 * HZ; | |
25 | ||
55a97593 TM |
26 | /* |
27 | * nfs_follow_mountpoint - handle crossing a mountpoint on the server | |
28 | * @dentry - dentry of mountpoint | |
29 | * @nd - nameidata info | |
30 | * | |
31 | * When we encounter a mountpoint on the server, we want to set up | |
32 | * a mountpoint on the client too, to prevent inode numbers from | |
33 | * colliding, and to allow "df" to work properly. | |
34 | * On NFSv4, we also want to allow for the fact that different | |
35 | * filesystems may be migrated to different servers in a failover | |
36 | * situation, and that different filesystems may want to use | |
37 | * different security flavours. | |
38 | */ | |
39 | static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
40 | { | |
41 | struct vfsmount *mnt; | |
42 | struct nfs_server *server = NFS_SERVER(dentry->d_inode); | |
43 | struct dentry *parent; | |
44 | struct nfs_fh fh; | |
45 | struct nfs_fattr fattr; | |
46 | int err; | |
47 | ||
48 | BUG_ON(IS_ROOT(dentry)); | |
49 | dprintk("%s: enter\n", __FUNCTION__); | |
50 | dput(nd->dentry); | |
51 | nd->dentry = dget(dentry); | |
52 | if (d_mountpoint(nd->dentry)) | |
53 | goto out_follow; | |
54 | /* Look it up again */ | |
55 | parent = dget_parent(nd->dentry); | |
56 | err = server->rpc_ops->lookup(parent->d_inode, &nd->dentry->d_name, &fh, &fattr); | |
57 | dput(parent); | |
58 | if (err != 0) | |
59 | goto out_err; | |
60 | ||
61 | mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr); | |
62 | err = PTR_ERR(mnt); | |
63 | if (IS_ERR(mnt)) | |
64 | goto out_err; | |
65 | ||
66 | mntget(mnt); | |
51d8fa6a | 67 | err = do_add_mount(mnt, nd, nd->mnt->mnt_flags|MNT_SHRINKABLE, &nfs_automount_list); |
55a97593 TM |
68 | if (err < 0) { |
69 | mntput(mnt); | |
70 | if (err == -EBUSY) | |
71 | goto out_follow; | |
72 | goto out_err; | |
73 | } | |
74 | mntput(nd->mnt); | |
75 | dput(nd->dentry); | |
76 | nd->mnt = mnt; | |
77 | nd->dentry = dget(mnt->mnt_root); | |
51d8fa6a | 78 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
55a97593 TM |
79 | out: |
80 | dprintk("%s: done, returned %d\n", __FUNCTION__, err); | |
81 | return ERR_PTR(err); | |
82 | out_err: | |
83 | path_release(nd); | |
84 | goto out; | |
85 | out_follow: | |
86 | while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) | |
87 | ; | |
88 | err = 0; | |
89 | goto out; | |
90 | } | |
91 | ||
92 | struct inode_operations nfs_mountpoint_inode_operations = { | |
93 | .follow_link = nfs_follow_mountpoint, | |
94 | .getattr = nfs_getattr, | |
95 | }; | |
51d8fa6a TM |
96 | |
97 | static void nfs_expire_automounts(void *data) | |
98 | { | |
99 | struct list_head *list = (struct list_head *)data; | |
100 | ||
101 | mark_mounts_for_expiry(list); | |
102 | if (!list_empty(list)) | |
103 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
104 | } | |
105 | ||
106 | void nfs_release_automount_timer(void) | |
107 | { | |
108 | if (list_empty(&nfs_automount_list)) { | |
109 | cancel_delayed_work(&nfs_automount_task); | |
110 | flush_scheduled_work(); | |
111 | } | |
112 | } |