~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/nfs/namespace.c

Version: ~ [ linux-5.6-rc1 ] ~ [ linux-5.5.2 ] ~ [ linux-5.4.17 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.102 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.170 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.213 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.213 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * linux/fs/nfs/namespace.c
  3  *
  4  * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
  5  * - Modified by David Howells <dhowells@redhat.com>
  6  *
  7  * NFS namespace
  8  */
  9 
 10 #include <linux/module.h>
 11 #include <linux/dcache.h>
 12 #include <linux/gfp.h>
 13 #include <linux/mount.h>
 14 #include <linux/namei.h>
 15 #include <linux/nfs_fs.h>
 16 #include <linux/string.h>
 17 #include <linux/sunrpc/clnt.h>
 18 #include <linux/vfs.h>
 19 #include <linux/sunrpc/gss_api.h>
 20 #include "internal.h"
 21 
 22 #define NFSDBG_FACILITY         NFSDBG_VFS
 23 
 24 static void nfs_expire_automounts(struct work_struct *work);
 25 
 26 static LIST_HEAD(nfs_automount_list);
 27 static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
 28 int nfs_mountpoint_expiry_timeout = 500 * HZ;
 29 
 30 /*
 31  * nfs_path - reconstruct the path given an arbitrary dentry
 32  * @base - used to return pointer to the end of devname part of path
 33  * @dentry - pointer to dentry
 34  * @buffer - result buffer
 35  * @buflen - length of buffer
 36  * @flags - options (see below)
 37  *
 38  * Helper function for constructing the server pathname
 39  * by arbitrary hashed dentry.
 40  *
 41  * This is mainly for use in figuring out the path on the
 42  * server side when automounting on top of an existing partition
 43  * and in generating /proc/mounts and friends.
 44  *
 45  * Supported flags:
 46  * NFS_PATH_CANONICAL: ensure there is exactly one slash after
 47  *                     the original device (export) name
 48  *                     (if unset, the original name is returned verbatim)
 49  */
 50 char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
 51                unsigned flags)
 52 {
 53         char *end;
 54         int namelen;
 55         unsigned seq;
 56         const char *base;
 57 
 58 rename_retry:
 59         end = buffer+buflen;
 60         *--end = '\0';
 61         buflen--;
 62 
 63         seq = read_seqbegin(&rename_lock);
 64         rcu_read_lock();
 65         while (1) {
 66                 spin_lock(&dentry->d_lock);
 67                 if (IS_ROOT(dentry))
 68                         break;
 69                 namelen = dentry->d_name.len;
 70                 buflen -= namelen + 1;
 71                 if (buflen < 0)
 72                         goto Elong_unlock;
 73                 end -= namelen;
 74                 memcpy(end, dentry->d_name.name, namelen);
 75                 *--end = '/';
 76                 spin_unlock(&dentry->d_lock);
 77                 dentry = dentry->d_parent;
 78         }
 79         if (read_seqretry(&rename_lock, seq)) {
 80                 spin_unlock(&dentry->d_lock);
 81                 rcu_read_unlock();
 82                 goto rename_retry;
 83         }
 84         if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
 85                 if (--buflen < 0) {
 86                         spin_unlock(&dentry->d_lock);
 87                         rcu_read_unlock();
 88                         goto Elong;
 89                 }
 90                 *--end = '/';
 91         }
 92         *p = end;
 93         base = dentry->d_fsdata;
 94         if (!base) {
 95                 spin_unlock(&dentry->d_lock);
 96                 rcu_read_unlock();
 97                 WARN_ON(1);
 98                 return end;
 99         }
100         namelen = strlen(base);
101         if (flags & NFS_PATH_CANONICAL) {
102                 /* Strip off excess slashes in base string */
103                 while (namelen > 0 && base[namelen - 1] == '/')
104                         namelen--;
105         }
106         buflen -= namelen;
107         if (buflen < 0) {
108                 spin_unlock(&dentry->d_lock);
109                 rcu_read_unlock();
110                 goto Elong;
111         }
112         end -= namelen;
113         memcpy(end, base, namelen);
114         spin_unlock(&dentry->d_lock);
115         rcu_read_unlock();
116         return end;
117 Elong_unlock:
118         spin_unlock(&dentry->d_lock);
119         rcu_read_unlock();
120         if (read_seqretry(&rename_lock, seq))
121                 goto rename_retry;
122 Elong:
123         return ERR_PTR(-ENAMETOOLONG);
124 }
125 EXPORT_SYMBOL_GPL(nfs_path);
126 
127 /*
128  * nfs_d_automount - Handle crossing a mountpoint on the server
129  * @path - The mountpoint
130  *
131  * When we encounter a mountpoint on the server, we want to set up
132  * a mountpoint on the client too, to prevent inode numbers from
133  * colliding, and to allow "df" to work properly.
134  * On NFSv4, we also want to allow for the fact that different
135  * filesystems may be migrated to different servers in a failover
136  * situation, and that different filesystems may want to use
137  * different security flavours.
138  */
139 struct vfsmount *nfs_d_automount(struct path *path)
140 {
141         struct vfsmount *mnt;
142         struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
143         struct nfs_fh *fh = NULL;
144         struct nfs_fattr *fattr = NULL;
145 
146         dprintk("--> nfs_d_automount()\n");
147 
148         mnt = ERR_PTR(-ESTALE);
149         if (IS_ROOT(path->dentry))
150                 goto out_nofree;
151 
152         mnt = ERR_PTR(-ENOMEM);
153         fh = nfs_alloc_fhandle();
154         fattr = nfs_alloc_fattr();
155         if (fh == NULL || fattr == NULL)
156                 goto out;
157 
158         dprintk("%s: enter\n", __func__);
159 
160         mnt = server->nfs_client->rpc_ops->submount(server, path->dentry, fh, fattr);
161         if (IS_ERR(mnt))
162                 goto out;
163 
164         dprintk("%s: done, success\n", __func__);
165         mntget(mnt); /* prevent immediate expiration */
166         mnt_set_expiry(mnt, &nfs_automount_list);
167         schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
168 
169 out:
170         nfs_free_fattr(fattr);
171         nfs_free_fhandle(fh);
172 out_nofree:
173         if (IS_ERR(mnt))
174                 dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt));
175         else
176                 dprintk("<-- %s() = %p\n", __func__, mnt);
177         return mnt;
178 }
179 
180 static int
181 nfs_namespace_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
182 {
183         if (NFS_FH(d_inode(dentry))->size != 0)
184                 return nfs_getattr(mnt, dentry, stat);
185         generic_fillattr(d_inode(dentry), stat);
186         return 0;
187 }
188 
189 static int
190 nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
191 {
192         if (NFS_FH(d_inode(dentry))->size != 0)
193                 return nfs_setattr(dentry, attr);
194         return -EACCES;
195 }
196 
197 const struct inode_operations nfs_mountpoint_inode_operations = {
198         .getattr        = nfs_getattr,
199         .setattr        = nfs_setattr,
200 };
201 
202 const struct inode_operations nfs_referral_inode_operations = {
203         .getattr        = nfs_namespace_getattr,
204         .setattr        = nfs_namespace_setattr,
205 };
206 
207 static void nfs_expire_automounts(struct work_struct *work)
208 {
209         struct list_head *list = &nfs_automount_list;
210 
211         mark_mounts_for_expiry(list);
212         if (!list_empty(list))
213                 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
214 }
215 
216 void nfs_release_automount_timer(void)
217 {
218         if (list_empty(&nfs_automount_list))
219                 cancel_delayed_work(&nfs_automount_task);
220 }
221 
222 /*
223  * Clone a mountpoint of the appropriate type
224  */
225 static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
226                                            const char *devname,
227                                            struct nfs_clone_mount *mountdata)
228 {
229         return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
230 }
231 
232 /**
233  * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
234  * @dentry - parent directory
235  * @fh - filehandle for new root dentry
236  * @fattr - attributes for new root inode
237  * @authflavor - security flavor to use when performing the mount
238  *
239  */
240 struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
241                                  struct nfs_fattr *fattr, rpc_authflavor_t authflavor)
242 {
243         struct nfs_clone_mount mountdata = {
244                 .sb = dentry->d_sb,
245                 .dentry = dentry,
246                 .fh = fh,
247                 .fattr = fattr,
248                 .authflavor = authflavor,
249         };
250         struct vfsmount *mnt = ERR_PTR(-ENOMEM);
251         char *page = (char *) __get_free_page(GFP_USER);
252         char *devname;
253 
254         dprintk("--> nfs_do_submount()\n");
255 
256         dprintk("%s: submounting on %pd2\n", __func__,
257                         dentry);
258         if (page == NULL)
259                 goto out;
260         devname = nfs_devname(dentry, page, PAGE_SIZE);
261         mnt = (struct vfsmount *)devname;
262         if (IS_ERR(devname))
263                 goto free_page;
264         mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
265 free_page:
266         free_page((unsigned long)page);
267 out:
268         dprintk("%s: done\n", __func__);
269 
270         dprintk("<-- nfs_do_submount() = %p\n", mnt);
271         return mnt;
272 }
273 EXPORT_SYMBOL_GPL(nfs_do_submount);
274 
275 struct vfsmount *nfs_submount(struct nfs_server *server, struct dentry *dentry,
276                               struct nfs_fh *fh, struct nfs_fattr *fattr)
277 {
278         int err;
279         struct dentry *parent = dget_parent(dentry);
280 
281         /* Look it up again to get its attributes */
282         err = server->nfs_client->rpc_ops->lookup(d_inode(parent), &dentry->d_name, fh, fattr, NULL);
283         dput(parent);
284         if (err != 0)
285                 return ERR_PTR(err);
286 
287         return nfs_do_submount(dentry, fh, fattr, server->client->cl_auth->au_flavor);
288 }
289 EXPORT_SYMBOL_GPL(nfs_submount);
290 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp