]>
Commit | Line | Data |
---|---|---|
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 | ||
21 | /* | |
22 | * nfs_follow_mountpoint - handle crossing a mountpoint on the server | |
23 | * @dentry - dentry of mountpoint | |
24 | * @nd - nameidata info | |
25 | * | |
26 | * When we encounter a mountpoint on the server, we want to set up | |
27 | * a mountpoint on the client too, to prevent inode numbers from | |
28 | * colliding, and to allow "df" to work properly. | |
29 | * On NFSv4, we also want to allow for the fact that different | |
30 | * filesystems may be migrated to different servers in a failover | |
31 | * situation, and that different filesystems may want to use | |
32 | * different security flavours. | |
33 | */ | |
34 | static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
35 | { | |
36 | struct vfsmount *mnt; | |
37 | struct nfs_server *server = NFS_SERVER(dentry->d_inode); | |
38 | struct dentry *parent; | |
39 | struct nfs_fh fh; | |
40 | struct nfs_fattr fattr; | |
41 | int err; | |
42 | ||
43 | BUG_ON(IS_ROOT(dentry)); | |
44 | dprintk("%s: enter\n", __FUNCTION__); | |
45 | dput(nd->dentry); | |
46 | nd->dentry = dget(dentry); | |
47 | if (d_mountpoint(nd->dentry)) | |
48 | goto out_follow; | |
49 | /* Look it up again */ | |
50 | parent = dget_parent(nd->dentry); | |
51 | err = server->rpc_ops->lookup(parent->d_inode, &nd->dentry->d_name, &fh, &fattr); | |
52 | dput(parent); | |
53 | if (err != 0) | |
54 | goto out_err; | |
55 | ||
56 | mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr); | |
57 | err = PTR_ERR(mnt); | |
58 | if (IS_ERR(mnt)) | |
59 | goto out_err; | |
60 | ||
61 | mntget(mnt); | |
62 | err = do_add_mount(mnt, nd, nd->mnt->mnt_flags, NULL); | |
63 | if (err < 0) { | |
64 | mntput(mnt); | |
65 | if (err == -EBUSY) | |
66 | goto out_follow; | |
67 | goto out_err; | |
68 | } | |
69 | mntput(nd->mnt); | |
70 | dput(nd->dentry); | |
71 | nd->mnt = mnt; | |
72 | nd->dentry = dget(mnt->mnt_root); | |
73 | out: | |
74 | dprintk("%s: done, returned %d\n", __FUNCTION__, err); | |
75 | return ERR_PTR(err); | |
76 | out_err: | |
77 | path_release(nd); | |
78 | goto out; | |
79 | out_follow: | |
80 | while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) | |
81 | ; | |
82 | err = 0; | |
83 | goto out; | |
84 | } | |
85 | ||
86 | struct inode_operations nfs_mountpoint_inode_operations = { | |
87 | .follow_link = nfs_follow_mountpoint, | |
88 | .getattr = nfs_getattr, | |
89 | }; |