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"
15 #define NFSDBG_FACILITY NFSDBG_VFS
17 static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
18 static void nfs4_evict_inode(struct inode *inode);
19 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
20 int flags, const char *dev_name, void *raw_data);
21 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
22 int flags, const char *dev_name, void *raw_data);
23 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
24 int flags, const char *dev_name, void *raw_data);
26 static struct file_system_type nfs4_fs_type = {
29 .mount = nfs_fs_mount,
30 .kill_sb = nfs_kill_super,
31 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
34 static struct file_system_type nfs4_remote_fs_type = {
37 .mount = nfs4_remote_mount,
38 .kill_sb = nfs_kill_super,
39 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
42 static struct file_system_type nfs4_remote_referral_fs_type = {
45 .mount = nfs4_remote_referral_mount,
46 .kill_sb = nfs_kill_super,
47 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
50 struct file_system_type nfs4_referral_fs_type = {
53 .mount = nfs4_referral_mount,
54 .kill_sb = nfs_kill_super,
55 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
58 static const struct super_operations nfs4_sops = {
59 .alloc_inode = nfs_alloc_inode,
60 .destroy_inode = nfs_destroy_inode,
61 .write_inode = nfs4_write_inode,
62 .put_super = nfs_put_super,
64 .evict_inode = nfs4_evict_inode,
65 .umount_begin = nfs_umount_begin,
66 .show_options = nfs_show_options,
67 .show_devname = nfs_show_devname,
68 .show_path = nfs_show_path,
69 .show_stats = nfs_show_stats,
70 .remount_fs = nfs_remount,
73 struct nfs_subversion nfs_v4 = {
75 .nfs_fs = &nfs4_fs_type,
76 .rpc_vers = &nfs_version4,
77 .rpc_ops = &nfs_v4_clientops,
79 .xattr = nfs4_xattr_handlers,
82 static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
84 int ret = nfs_write_inode(inode, wbc);
86 if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
90 if (wbc->sync_mode == WB_SYNC_NONE)
93 status = pnfs_layoutcommit_inode(inode, sync);
101 * Clean out any remaining NFSv4 state that might be left over due
102 * to open() calls that passed nfs_atomic_lookup, but failed to call
105 static void nfs4_evict_inode(struct inode *inode)
107 truncate_inode_pages(&inode->i_data, 0);
109 pnfs_return_layout(inode);
110 pnfs_destroy_layout(NFS_I(inode));
111 /* If we are holding a delegation, return it! */
112 nfs_inode_return_delegation_noreclaim(inode);
113 /* First call standard NFS clear_inode() code */
114 nfs_clear_inode(inode);
118 * Get the superblock for the NFS4 root partition
120 static struct dentry *
121 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
122 const char *dev_name, void *info)
124 struct nfs_mount_info *mount_info = info;
125 struct nfs_server *server;
126 struct dentry *mntroot = ERR_PTR(-ENOMEM);
128 mount_info->set_security = nfs_set_sb_security;
130 /* Get a volume representation */
131 server = nfs4_create_server(mount_info, &nfs_v4);
132 if (IS_ERR(server)) {
133 mntroot = ERR_CAST(server);
137 mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
143 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
144 int flags, void *data, const char *hostname)
146 struct vfsmount *root_mnt;
150 len = strlen(hostname) + 5;
151 root_devname = kmalloc(len, GFP_KERNEL);
152 if (root_devname == NULL)
153 return ERR_PTR(-ENOMEM);
154 /* Does hostname needs to be enclosed in brackets? */
155 if (strchr(hostname, ':'))
156 snprintf(root_devname, len, "[%s]:/", hostname);
158 snprintf(root_devname, len, "%s:/", hostname);
159 root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
164 struct nfs_referral_count {
165 struct list_head list;
166 const struct task_struct *task;
167 unsigned int referral_count;
170 static LIST_HEAD(nfs_referral_count_list);
171 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
173 static struct nfs_referral_count *nfs_find_referral_count(void)
175 struct nfs_referral_count *p;
177 list_for_each_entry(p, &nfs_referral_count_list, list) {
178 if (p->task == current)
184 #define NFS_MAX_NESTED_REFERRALS 2
186 static int nfs_referral_loop_protect(void)
188 struct nfs_referral_count *p, *new;
191 new = kmalloc(sizeof(*new), GFP_KERNEL);
195 new->referral_count = 1;
198 spin_lock(&nfs_referral_count_list_lock);
199 p = nfs_find_referral_count();
201 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
206 list_add(&new->list, &nfs_referral_count_list);
209 spin_unlock(&nfs_referral_count_list_lock);
215 static void nfs_referral_loop_unprotect(void)
217 struct nfs_referral_count *p;
219 spin_lock(&nfs_referral_count_list_lock);
220 p = nfs_find_referral_count();
222 if (p->referral_count == 0)
226 spin_unlock(&nfs_referral_count_list_lock);
230 static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
231 const char *export_path)
233 struct dentry *dentry;
236 if (IS_ERR(root_mnt))
237 return ERR_CAST(root_mnt);
239 err = nfs_referral_loop_protect();
245 dentry = mount_subtree(root_mnt, export_path);
246 nfs_referral_loop_unprotect();
251 struct dentry *nfs4_try_mount(int flags, const char *dev_name,
252 struct nfs_mount_info *mount_info,
253 struct nfs_subversion *nfs_mod)
256 struct vfsmount *root_mnt;
258 struct nfs_parsed_mount_data *data = mount_info->parsed;
260 dfprintk(MOUNT, "--> nfs4_try_mount()\n");
262 export_path = data->nfs_server.export_path;
263 data->nfs_server.export_path = "/";
264 root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
265 data->nfs_server.hostname);
266 data->nfs_server.export_path = export_path;
268 res = nfs_follow_remote_path(root_mnt, export_path);
270 dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
271 IS_ERR(res) ? PTR_ERR(res) : 0,
272 IS_ERR(res) ? " [error]" : "");
276 static struct dentry *
277 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
278 const char *dev_name, void *raw_data)
280 struct nfs_mount_info mount_info = {
281 .fill_super = nfs_fill_super,
282 .set_security = nfs_clone_sb_security,
285 struct nfs_server *server;
286 struct dentry *mntroot = ERR_PTR(-ENOMEM);
288 dprintk("--> nfs4_referral_get_sb()\n");
290 mount_info.mntfh = nfs_alloc_fhandle();
291 if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
294 /* create a new volume representation */
295 server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
296 if (IS_ERR(server)) {
297 mntroot = ERR_CAST(server);
301 mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
303 nfs_free_fhandle(mount_info.mntfh);
308 * Create an NFS4 server record on referral traversal
310 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
311 int flags, const char *dev_name, void *raw_data)
313 struct nfs_clone_mount *data = raw_data;
315 struct vfsmount *root_mnt;
318 dprintk("--> nfs4_referral_mount()\n");
320 export_path = data->mnt_path;
321 data->mnt_path = "/";
323 root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
324 flags, data, data->hostname);
325 data->mnt_path = export_path;
327 res = nfs_follow_remote_path(root_mnt, export_path);
328 dprintk("<-- nfs4_referral_mount() = %ld%s\n",
329 IS_ERR(res) ? PTR_ERR(res) : 0,
330 IS_ERR(res) ? " [error]" : "");
335 static int __init init_nfs_v4(void)
339 err = nfs_idmap_init();
343 err = nfs4_register_sysctl();
347 err = register_filesystem(&nfs4_fs_type);
351 register_nfs_version(&nfs_v4);
354 nfs4_unregister_sysctl();
361 static void __exit exit_nfs_v4(void)
363 unregister_nfs_version(&nfs_v4);
364 unregister_filesystem(&nfs4_fs_type);
365 nfs4_unregister_sysctl();
369 MODULE_LICENSE("GPL");
371 module_init(init_nfs_v4);
372 module_exit(exit_nfs_v4);