2 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
4 #include <linux/init.h>
5 #include <linux/module.h>
6 #include <linux/nfs_idmap.h>
7 #include <linux/nfs4_mount.h>
8 #include <linux/nfs_fs.h>
9 #include "delegation.h"
12 #include "dns_resolve.h"
16 #define NFSDBG_FACILITY NFSDBG_VFS
18 static int nfs4_write_inode(struct inode
*inode
, struct writeback_control
*wbc
);
19 static void nfs4_evict_inode(struct inode
*inode
);
20 static struct dentry
*nfs4_remote_mount(struct file_system_type
*fs_type
,
21 int flags
, const char *dev_name
, void *raw_data
);
22 static struct dentry
*nfs4_referral_mount(struct file_system_type
*fs_type
,
23 int flags
, const char *dev_name
, void *raw_data
);
24 static struct dentry
*nfs4_remote_referral_mount(struct file_system_type
*fs_type
,
25 int flags
, const char *dev_name
, void *raw_data
);
27 static struct file_system_type nfs4_remote_fs_type
= {
30 .mount
= nfs4_remote_mount
,
31 .kill_sb
= nfs_kill_super
,
32 .fs_flags
= FS_RENAME_DOES_D_MOVE
|FS_BINARY_MOUNTDATA
,
35 static struct file_system_type nfs4_remote_referral_fs_type
= {
38 .mount
= nfs4_remote_referral_mount
,
39 .kill_sb
= nfs_kill_super
,
40 .fs_flags
= FS_RENAME_DOES_D_MOVE
|FS_BINARY_MOUNTDATA
,
43 struct file_system_type nfs4_referral_fs_type
= {
46 .mount
= nfs4_referral_mount
,
47 .kill_sb
= nfs_kill_super
,
48 .fs_flags
= FS_RENAME_DOES_D_MOVE
|FS_BINARY_MOUNTDATA
,
51 static const struct super_operations nfs4_sops
= {
52 .alloc_inode
= nfs_alloc_inode
,
53 .destroy_inode
= nfs_destroy_inode
,
54 .write_inode
= nfs4_write_inode
,
55 .drop_inode
= nfs_drop_inode
,
56 .put_super
= nfs_put_super
,
58 .evict_inode
= nfs4_evict_inode
,
59 .umount_begin
= nfs_umount_begin
,
60 .show_options
= nfs_show_options
,
61 .show_devname
= nfs_show_devname
,
62 .show_path
= nfs_show_path
,
63 .show_stats
= nfs_show_stats
,
64 .remount_fs
= nfs_remount
,
67 struct nfs_subversion nfs_v4
= {
69 .nfs_fs
= &nfs4_fs_type
,
70 .rpc_vers
= &nfs_version4
,
71 .rpc_ops
= &nfs_v4_clientops
,
73 .xattr
= nfs4_xattr_handlers
,
76 static int nfs4_write_inode(struct inode
*inode
, struct writeback_control
*wbc
)
78 int ret
= nfs_write_inode(inode
, wbc
);
80 if (ret
>= 0 && test_bit(NFS_INO_LAYOUTCOMMIT
, &NFS_I(inode
)->flags
)) {
84 if (wbc
->sync_mode
== WB_SYNC_NONE
)
87 status
= pnfs_layoutcommit_inode(inode
, sync
);
95 * Clean out any remaining NFSv4 state that might be left over due
96 * to open() calls that passed nfs_atomic_lookup, but failed to call
99 static void nfs4_evict_inode(struct inode
*inode
)
101 truncate_inode_pages(&inode
->i_data
, 0);
103 pnfs_return_layout(inode
);
104 pnfs_destroy_layout(NFS_I(inode
));
105 /* If we are holding a delegation, return it! */
106 nfs_inode_return_delegation_noreclaim(inode
);
107 /* First call standard NFS clear_inode() code */
108 nfs_clear_inode(inode
);
112 * Get the superblock for the NFS4 root partition
114 static struct dentry
*
115 nfs4_remote_mount(struct file_system_type
*fs_type
, int flags
,
116 const char *dev_name
, void *info
)
118 struct nfs_mount_info
*mount_info
= info
;
119 struct nfs_server
*server
;
120 struct dentry
*mntroot
= ERR_PTR(-ENOMEM
);
122 mount_info
->set_security
= nfs_set_sb_security
;
124 /* Get a volume representation */
125 server
= nfs4_create_server(mount_info
, &nfs_v4
);
126 if (IS_ERR(server
)) {
127 mntroot
= ERR_CAST(server
);
131 mntroot
= nfs_fs_mount_common(server
, flags
, dev_name
, mount_info
, &nfs_v4
);
137 static struct vfsmount
*nfs_do_root_mount(struct file_system_type
*fs_type
,
138 int flags
, void *data
, const char *hostname
)
140 struct vfsmount
*root_mnt
;
144 len
= strlen(hostname
) + 5;
145 root_devname
= kmalloc(len
, GFP_KERNEL
);
146 if (root_devname
== NULL
)
147 return ERR_PTR(-ENOMEM
);
148 /* Does hostname needs to be enclosed in brackets? */
149 if (strchr(hostname
, ':'))
150 snprintf(root_devname
, len
, "[%s]:/", hostname
);
152 snprintf(root_devname
, len
, "%s:/", hostname
);
153 root_mnt
= vfs_kern_mount(fs_type
, flags
, root_devname
, data
);
158 struct nfs_referral_count
{
159 struct list_head list
;
160 const struct task_struct
*task
;
161 unsigned int referral_count
;
164 static LIST_HEAD(nfs_referral_count_list
);
165 static DEFINE_SPINLOCK(nfs_referral_count_list_lock
);
167 static struct nfs_referral_count
*nfs_find_referral_count(void)
169 struct nfs_referral_count
*p
;
171 list_for_each_entry(p
, &nfs_referral_count_list
, list
) {
172 if (p
->task
== current
)
178 #define NFS_MAX_NESTED_REFERRALS 2
180 static int nfs_referral_loop_protect(void)
182 struct nfs_referral_count
*p
, *new;
185 new = kmalloc(sizeof(*new), GFP_KERNEL
);
189 new->referral_count
= 1;
192 spin_lock(&nfs_referral_count_list_lock
);
193 p
= nfs_find_referral_count();
195 if (p
->referral_count
>= NFS_MAX_NESTED_REFERRALS
)
200 list_add(&new->list
, &nfs_referral_count_list
);
203 spin_unlock(&nfs_referral_count_list_lock
);
209 static void nfs_referral_loop_unprotect(void)
211 struct nfs_referral_count
*p
;
213 spin_lock(&nfs_referral_count_list_lock
);
214 p
= nfs_find_referral_count();
216 if (p
->referral_count
== 0)
220 spin_unlock(&nfs_referral_count_list_lock
);
224 static struct dentry
*nfs_follow_remote_path(struct vfsmount
*root_mnt
,
225 const char *export_path
)
227 struct dentry
*dentry
;
230 if (IS_ERR(root_mnt
))
231 return ERR_CAST(root_mnt
);
233 err
= nfs_referral_loop_protect();
239 dentry
= mount_subtree(root_mnt
, export_path
);
240 nfs_referral_loop_unprotect();
245 struct dentry
*nfs4_try_mount(int flags
, const char *dev_name
,
246 struct nfs_mount_info
*mount_info
,
247 struct nfs_subversion
*nfs_mod
)
250 struct vfsmount
*root_mnt
;
252 struct nfs_parsed_mount_data
*data
= mount_info
->parsed
;
254 dfprintk(MOUNT
, "--> nfs4_try_mount()\n");
256 export_path
= data
->nfs_server
.export_path
;
257 data
->nfs_server
.export_path
= "/";
258 root_mnt
= nfs_do_root_mount(&nfs4_remote_fs_type
, flags
, mount_info
,
259 data
->nfs_server
.hostname
);
260 data
->nfs_server
.export_path
= export_path
;
262 res
= nfs_follow_remote_path(root_mnt
, export_path
);
264 dfprintk(MOUNT
, "<-- nfs4_try_mount() = %ld%s\n",
265 IS_ERR(res
) ? PTR_ERR(res
) : 0,
266 IS_ERR(res
) ? " [error]" : "");
270 static struct dentry
*
271 nfs4_remote_referral_mount(struct file_system_type
*fs_type
, int flags
,
272 const char *dev_name
, void *raw_data
)
274 struct nfs_mount_info mount_info
= {
275 .fill_super
= nfs_fill_super
,
276 .set_security
= nfs_clone_sb_security
,
279 struct nfs_server
*server
;
280 struct dentry
*mntroot
= ERR_PTR(-ENOMEM
);
282 dprintk("--> nfs4_referral_get_sb()\n");
284 mount_info
.mntfh
= nfs_alloc_fhandle();
285 if (mount_info
.cloned
== NULL
|| mount_info
.mntfh
== NULL
)
288 /* create a new volume representation */
289 server
= nfs4_create_referral_server(mount_info
.cloned
, mount_info
.mntfh
);
290 if (IS_ERR(server
)) {
291 mntroot
= ERR_CAST(server
);
295 mntroot
= nfs_fs_mount_common(server
, flags
, dev_name
, &mount_info
, &nfs_v4
);
297 nfs_free_fhandle(mount_info
.mntfh
);
302 * Create an NFS4 server record on referral traversal
304 static struct dentry
*nfs4_referral_mount(struct file_system_type
*fs_type
,
305 int flags
, const char *dev_name
, void *raw_data
)
307 struct nfs_clone_mount
*data
= raw_data
;
309 struct vfsmount
*root_mnt
;
312 dprintk("--> nfs4_referral_mount()\n");
314 export_path
= data
->mnt_path
;
315 data
->mnt_path
= "/";
317 root_mnt
= nfs_do_root_mount(&nfs4_remote_referral_fs_type
,
318 flags
, data
, data
->hostname
);
319 data
->mnt_path
= export_path
;
321 res
= nfs_follow_remote_path(root_mnt
, export_path
);
322 dprintk("<-- nfs4_referral_mount() = %ld%s\n",
323 IS_ERR(res
) ? PTR_ERR(res
) : 0,
324 IS_ERR(res
) ? " [error]" : "");
329 static int __init
init_nfs_v4(void)
333 err
= nfs_dns_resolver_init();
337 err
= nfs_idmap_init();
341 err
= nfs4_register_sysctl();
345 register_nfs_version(&nfs_v4
);
350 nfs_dns_resolver_destroy();
355 static void __exit
exit_nfs_v4(void)
357 unregister_nfs_version(&nfs_v4
);
358 nfs4_unregister_sysctl();
360 nfs_dns_resolver_destroy();
363 MODULE_LICENSE("GPL");
365 module_init(init_nfs_v4
);
366 module_exit(exit_nfs_v4
);