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,
57 .evict_inode = nfs4_evict_inode,
58 .umount_begin = nfs_umount_begin,
59 .show_options = nfs_show_options,
60 .show_devname = nfs_show_devname,
61 .show_path = nfs_show_path,
62 .show_stats = nfs_show_stats,
63 .remount_fs = nfs_remount,
66 struct nfs_subversion nfs_v4 = {
68 .nfs_fs = &nfs4_fs_type,
69 .rpc_vers = &nfs_version4,
70 .rpc_ops = &nfs_v4_clientops,
72 .xattr = nfs4_xattr_handlers,
75 static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
77 int ret = nfs_write_inode(inode, wbc);
80 ret = pnfs_layoutcommit_inode(inode,
81 wbc->sync_mode == WB_SYNC_ALL);
86 * Clean out any remaining NFSv4 state that might be left over due
87 * to open() calls that passed nfs_atomic_lookup, but failed to call
90 static void nfs4_evict_inode(struct inode *inode)
92 truncate_inode_pages_final(&inode->i_data);
94 pnfs_return_layout(inode);
95 pnfs_destroy_layout(NFS_I(inode));
96 /* If we are holding a delegation, return it! */
97 nfs_inode_return_delegation_noreclaim(inode);
98 /* First call standard NFS clear_inode() code */
99 nfs_clear_inode(inode);
103 * Get the superblock for the NFS4 root partition
105 static struct dentry *
106 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
107 const char *dev_name, void *info)
109 struct nfs_mount_info *mount_info = info;
110 struct nfs_server *server;
111 struct dentry *mntroot = ERR_PTR(-ENOMEM);
113 mount_info->set_security = nfs_set_sb_security;
115 /* Get a volume representation */
116 server = nfs4_create_server(mount_info, &nfs_v4);
117 if (IS_ERR(server)) {
118 mntroot = ERR_CAST(server);
122 mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
128 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
129 int flags, void *data, const char *hostname)
131 struct vfsmount *root_mnt;
135 len = strlen(hostname) + 5;
136 root_devname = kmalloc(len, GFP_KERNEL);
137 if (root_devname == NULL)
138 return ERR_PTR(-ENOMEM);
139 /* Does hostname needs to be enclosed in brackets? */
140 if (strchr(hostname, ':'))
141 snprintf(root_devname, len, "[%s]:/", hostname);
143 snprintf(root_devname, len, "%s:/", hostname);
144 root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
149 struct nfs_referral_count {
150 struct list_head list;
151 const struct task_struct *task;
152 unsigned int referral_count;
155 static LIST_HEAD(nfs_referral_count_list);
156 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
158 static struct nfs_referral_count *nfs_find_referral_count(void)
160 struct nfs_referral_count *p;
162 list_for_each_entry(p, &nfs_referral_count_list, list) {
163 if (p->task == current)
169 #define NFS_MAX_NESTED_REFERRALS 2
171 static int nfs_referral_loop_protect(void)
173 struct nfs_referral_count *p, *new;
176 new = kmalloc(sizeof(*new), GFP_KERNEL);
180 new->referral_count = 1;
183 spin_lock(&nfs_referral_count_list_lock);
184 p = nfs_find_referral_count();
186 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
191 list_add(&new->list, &nfs_referral_count_list);
194 spin_unlock(&nfs_referral_count_list_lock);
200 static void nfs_referral_loop_unprotect(void)
202 struct nfs_referral_count *p;
204 spin_lock(&nfs_referral_count_list_lock);
205 p = nfs_find_referral_count();
207 if (p->referral_count == 0)
211 spin_unlock(&nfs_referral_count_list_lock);
215 static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
216 const char *export_path)
218 struct dentry *dentry;
221 if (IS_ERR(root_mnt))
222 return ERR_CAST(root_mnt);
224 err = nfs_referral_loop_protect();
230 dentry = mount_subtree(root_mnt, export_path);
231 nfs_referral_loop_unprotect();
236 struct dentry *nfs4_try_mount(int flags, const char *dev_name,
237 struct nfs_mount_info *mount_info,
238 struct nfs_subversion *nfs_mod)
241 struct vfsmount *root_mnt;
243 struct nfs_parsed_mount_data *data = mount_info->parsed;
245 dfprintk(MOUNT, "--> nfs4_try_mount()\n");
247 export_path = data->nfs_server.export_path;
248 data->nfs_server.export_path = "/";
249 root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
250 data->nfs_server.hostname);
251 data->nfs_server.export_path = export_path;
253 res = nfs_follow_remote_path(root_mnt, export_path);
255 dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
256 PTR_ERR_OR_ZERO(res),
257 IS_ERR(res) ? " [error]" : "");
261 static struct dentry *
262 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
263 const char *dev_name, void *raw_data)
265 struct nfs_mount_info mount_info = {
266 .fill_super = nfs_fill_super,
267 .set_security = nfs_clone_sb_security,
270 struct nfs_server *server;
271 struct dentry *mntroot = ERR_PTR(-ENOMEM);
273 dprintk("--> nfs4_referral_get_sb()\n");
275 mount_info.mntfh = nfs_alloc_fhandle();
276 if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
279 /* create a new volume representation */
280 server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
281 if (IS_ERR(server)) {
282 mntroot = ERR_CAST(server);
286 mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
288 nfs_free_fhandle(mount_info.mntfh);
293 * Create an NFS4 server record on referral traversal
295 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
296 int flags, const char *dev_name, void *raw_data)
298 struct nfs_clone_mount *data = raw_data;
300 struct vfsmount *root_mnt;
303 dprintk("--> nfs4_referral_mount()\n");
305 export_path = data->mnt_path;
306 data->mnt_path = "/";
308 root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
309 flags, data, data->hostname);
310 data->mnt_path = export_path;
312 res = nfs_follow_remote_path(root_mnt, export_path);
313 dprintk("<-- nfs4_referral_mount() = %d%s\n",
314 PTR_ERR_OR_ZERO(res),
315 IS_ERR(res) ? " [error]" : "");
320 static int __init init_nfs_v4(void)
324 err = nfs_dns_resolver_init();
328 err = nfs_idmap_init();
332 err = nfs4_register_sysctl();
336 register_nfs_version(&nfs_v4);
341 nfs_dns_resolver_destroy();
346 static void __exit exit_nfs_v4(void)
348 /* Not called in the _init(), conditionally loaded */
349 nfs4_pnfs_v3_ds_connect_unload();
351 unregister_nfs_version(&nfs_v4);
352 nfs4_unregister_sysctl();
354 nfs_dns_resolver_destroy();
357 MODULE_LICENSE("GPL");
359 module_init(init_nfs_v4);
360 module_exit(exit_nfs_v4);