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

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

Version: ~ [ linux-5.12-rc5 ] ~ [ linux-5.11.11 ] ~ [ linux-5.10.27 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.109 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.184 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.228 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.264 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.264 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ 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 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/fs/nfs/namespace.c
  4  *
  5  * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
  6  * - Modified by David Howells <dhowells@redhat.com>
  7  *
  8  * NFS namespace
  9  */
 10 
 11 #include <linux/module.h>
 12 #include <linux/dcache.h>
 13 #include <linux/gfp.h>
 14 #include <linux/mount.h>
 15 #include <linux/namei.h>
 16 #include <linux/nfs_fs.h>
 17 #include <linux/string.h>
 18 #include <linux/sunrpc/clnt.h>
 19 #include <linux/vfs.h>
 20 #include <linux/sunrpc/gss_api.h>
 21 #include "internal.h"
 22 
 23 #define NFSDBG_FACILITY         NFSDBG_VFS
 24 
 25 static void nfs_expire_automounts(struct work_struct *work);
 26 
 27 static LIST_HEAD(nfs_automount_list);
 28 static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
 29 int nfs_mountpoint_expiry_timeout = 500 * HZ;
 30 
 31 /*
 32  * nfs_path - reconstruct the path given an arbitrary dentry
 33  * @base - used to return pointer to the end of devname part of path
 34  * @dentry - pointer to dentry
 35  * @buffer - result buffer
 36  * @buflen - length of buffer
 37  * @flags - options (see below)
 38  *
 39  * Helper function for constructing the server pathname
 40  * by arbitrary hashed dentry.
 41  *
 42  * This is mainly for use in figuring out the path on the
 43  * server side when automounting on top of an existing partition
 44  * and in generating /proc/mounts and friends.
 45  *
 46  * Supported flags:
 47  * NFS_PATH_CANONICAL: ensure there is exactly one slash after
 48  *                     the original device (export) name
 49  *                     (if unset, the original name is returned verbatim)
 50  */
 51 char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
 52                unsigned flags)
 53 {
 54         char *end;
 55         int namelen;
 56         unsigned seq;
 57         const char *base;
 58 
 59 rename_retry:
 60         end = buffer+buflen;
 61         *--end = '\0';
 62         buflen--;
 63 
 64         seq = read_seqbegin(&rename_lock);
 65         rcu_read_lock();
 66         while (1) {
 67                 spin_lock(&dentry->d_lock);
 68                 if (IS_ROOT(dentry))
 69                         break;
 70                 namelen = dentry->d_name.len;
 71                 buflen -= namelen + 1;
 72                 if (buflen < 0)
 73                         goto Elong_unlock;
 74                 end -= namelen;
 75                 memcpy(end, dentry->d_name.name, namelen);
 76                 *--end = '/';
 77                 spin_unlock(&dentry->d_lock);
 78                 dentry = dentry->d_parent;
 79         }
 80         if (read_seqretry(&rename_lock, seq)) {
 81                 spin_unlock(&dentry->d_lock);
 82                 rcu_read_unlock();
 83                 goto rename_retry;
 84         }
 85         if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
 86                 if (--buflen < 0) {
 87                         spin_unlock(&dentry->d_lock);
 88                         rcu_read_unlock();
 89                         goto Elong;
 90                 }
 91                 *--end = '/';
 92         }
 93         *p = end;
 94         base = dentry->d_fsdata;
 95         if (!base) {
 96                 spin_unlock(&dentry->d_lock);
 97                 rcu_read_unlock();
 98                 WARN_ON(1);
 99                 return end;
100         }
101         namelen = strlen(base);
102         if (*end == '/') {
103                 /* Strip off excess slashes in base string */
104                 while (namelen > 0 && base[namelen - 1] == '/')
105                         namelen--;
106         }
107         buflen -= namelen;
108         if (buflen < 0) {
109                 spin_unlock(&dentry->d_lock);
110                 rcu_read_unlock();
111                 goto Elong;
112         }
113         end -= namelen;
114         memcpy(end, base, namelen);
115         spin_unlock(&dentry->d_lock);
116         rcu_read_unlock();
117         return end;
118 Elong_unlock:
119         spin_unlock(&dentry->d_lock);
120         rcu_read_unlock();
121         if (read_seqretry(&rename_lock, seq))
122                 goto rename_retry;
123 Elong:
124         return ERR_PTR(-ENAMETOOLONG);
125 }
126 EXPORT_SYMBOL_GPL(nfs_path);
127 
128 /*
129  * nfs_d_automount - Handle crossing a mountpoint on the server
130  * @path - The mountpoint
131  *
132  * When we encounter a mountpoint on the server, we want to set up
133  * a mountpoint on the client too, to prevent inode numbers from
134  * colliding, and to allow "df" to work properly.
135  * On NFSv4, we also want to allow for the fact that different
136  * filesystems may be migrated to different servers in a failover
137  * situation, and that different filesystems may want to use
138  * different security flavours.
139  */
140 struct vfsmount *nfs_d_automount(struct path *path)
141 {
142         struct vfsmount *mnt;
143         struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
144         struct nfs_fh *fh = NULL;
145         struct nfs_fattr *fattr = NULL;
146 
147         if (IS_ROOT(path->dentry))
148                 return ERR_PTR(-ESTALE);
149 
150         mnt = ERR_PTR(-ENOMEM);
151         fh = nfs_alloc_fhandle();
152         fattr = nfs_alloc_fattr();
153         if (fh == NULL || fattr == NULL)
154                 goto out;
155 
156         mnt = server->nfs_client->rpc_ops->submount(server, path->dentry, fh, fattr);
157         if (IS_ERR(mnt))
158                 goto out;
159 
160         mntget(mnt); /* prevent immediate expiration */
161         mnt_set_expiry(mnt, &nfs_automount_list);
162         schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
163 
164 out:
165         nfs_free_fattr(fattr);
166         nfs_free_fhandle(fh);
167         return mnt;
168 }
169 
170 static int
171 nfs_namespace_getattr(const struct path *path, struct kstat *stat,
172                         u32 request_mask, unsigned int query_flags)
173 {
174         if (NFS_FH(d_inode(path->dentry))->size != 0)
175                 return nfs_getattr(path, stat, request_mask, query_flags);
176         generic_fillattr(d_inode(path->dentry), stat);
177         return 0;
178 }
179 
180 static int
181 nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
182 {
183         if (NFS_FH(d_inode(dentry))->size != 0)
184                 return nfs_setattr(dentry, attr);
185         return -EACCES;
186 }
187 
188 const struct inode_operations nfs_mountpoint_inode_operations = {
189         .getattr        = nfs_getattr,
190         .setattr        = nfs_setattr,
191 };
192 
193 const struct inode_operations nfs_referral_inode_operations = {
194         .getattr        = nfs_namespace_getattr,
195         .setattr        = nfs_namespace_setattr,
196 };
197 
198 static void nfs_expire_automounts(struct work_struct *work)
199 {
200         struct list_head *list = &nfs_automount_list;
201 
202         mark_mounts_for_expiry(list);
203         if (!list_empty(list))
204                 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
205 }
206 
207 void nfs_release_automount_timer(void)
208 {
209         if (list_empty(&nfs_automount_list))
210                 cancel_delayed_work(&nfs_automount_task);
211 }
212 
213 /*
214  * Clone a mountpoint of the appropriate type
215  */
216 static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
217                                            const char *devname,
218                                            struct nfs_clone_mount *mountdata)
219 {
220         return vfs_submount(mountdata->dentry, &nfs_xdev_fs_type, devname, mountdata);
221 }
222 
223 /**
224  * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
225  * @dentry: parent directory
226  * @fh: filehandle for new root dentry
227  * @fattr: attributes for new root inode
228  * @authflavor: security flavor to use when performing the mount
229  *
230  */
231 struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
232                                  struct nfs_fattr *fattr, rpc_authflavor_t authflavor)
233 {
234         struct nfs_clone_mount mountdata = {
235                 .sb = dentry->d_sb,
236                 .dentry = dentry,
237                 .fh = fh,
238                 .fattr = fattr,
239                 .authflavor = authflavor,
240         };
241         struct vfsmount *mnt;
242         char *page = (char *) __get_free_page(GFP_USER);
243         char *devname;
244 
245         if (page == NULL)
246                 return ERR_PTR(-ENOMEM);
247 
248         devname = nfs_devname(dentry, page, PAGE_SIZE);
249         if (IS_ERR(devname))
250                 mnt = ERR_CAST(devname);
251         else
252                 mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
253 
254         free_page((unsigned long)page);
255         return mnt;
256 }
257 EXPORT_SYMBOL_GPL(nfs_do_submount);
258 
259 struct vfsmount *nfs_submount(struct nfs_server *server, struct dentry *dentry,
260                               struct nfs_fh *fh, struct nfs_fattr *fattr)
261 {
262         int err;
263         struct dentry *parent = dget_parent(dentry);
264 
265         /* Look it up again to get its attributes */
266         err = server->nfs_client->rpc_ops->lookup(d_inode(parent), &dentry->d_name, fh, fattr, NULL);
267         dput(parent);
268         if (err != 0)
269                 return ERR_PTR(err);
270 
271         return nfs_do_submount(dentry, fh, fattr, server->client->cl_auth->au_flavor);
272 }
273 EXPORT_SYMBOL_GPL(nfs_submount);
274 

~ [ 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