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

TOMOYO Linux Cross Reference
Linux/fs/afs/mntpt.c

Version: ~ [ linux-5.8-rc4 ] ~ [ linux-5.7.7 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.50 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.131 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.187 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.229 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.229 ] ~ [ 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-3.16.85 ] ~ [ 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-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 /* mountpoint management
  2  *
  3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
  4  * Written by David Howells (dhowells@redhat.com)
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of the GNU General Public License
  8  * as published by the Free Software Foundation; either version
  9  * 2 of the License, or (at your option) any later version.
 10  */
 11 
 12 #include <linux/kernel.h>
 13 #include <linux/module.h>
 14 #include <linux/init.h>
 15 #include <linux/fs.h>
 16 #include <linux/pagemap.h>
 17 #include <linux/mount.h>
 18 #include <linux/namei.h>
 19 #include <linux/gfp.h>
 20 #include "internal.h"
 21 
 22 
 23 static struct dentry *afs_mntpt_lookup(struct inode *dir,
 24                                        struct dentry *dentry,
 25                                        unsigned int flags);
 26 static int afs_mntpt_open(struct inode *inode, struct file *file);
 27 static void afs_mntpt_expiry_timed_out(struct work_struct *work);
 28 
 29 const struct file_operations afs_mntpt_file_operations = {
 30         .open           = afs_mntpt_open,
 31         .llseek         = noop_llseek,
 32 };
 33 
 34 const struct inode_operations afs_mntpt_inode_operations = {
 35         .lookup         = afs_mntpt_lookup,
 36         .readlink       = page_readlink,
 37         .getattr        = afs_getattr,
 38 };
 39 
 40 const struct inode_operations afs_autocell_inode_operations = {
 41         .getattr        = afs_getattr,
 42 };
 43 
 44 static LIST_HEAD(afs_vfsmounts);
 45 static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
 46 
 47 static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
 48 
 49 /*
 50  * check a symbolic link to see whether it actually encodes a mountpoint
 51  * - sets the AFS_VNODE_MOUNTPOINT flag on the vnode appropriately
 52  */
 53 int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
 54 {
 55         struct page *page;
 56         size_t size;
 57         char *buf;
 58         int ret;
 59 
 60         _enter("{%x:%u,%u}",
 61                vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
 62 
 63         /* read the contents of the symlink into the pagecache */
 64         page = read_cache_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0,
 65                                afs_page_filler, key);
 66         if (IS_ERR(page)) {
 67                 ret = PTR_ERR(page);
 68                 goto out;
 69         }
 70 
 71         ret = -EIO;
 72         if (PageError(page))
 73                 goto out_free;
 74 
 75         buf = kmap(page);
 76 
 77         /* examine the symlink's contents */
 78         size = vnode->status.size;
 79         _debug("symlink to %*.*s", (int) size, (int) size, buf);
 80 
 81         if (size > 2 &&
 82             (buf[0] == '%' || buf[0] == '#') &&
 83             buf[size - 1] == '.'
 84             ) {
 85                 _debug("symlink is a mountpoint");
 86                 spin_lock(&vnode->lock);
 87                 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
 88                 vnode->vfs_inode.i_flags |= S_AUTOMOUNT;
 89                 spin_unlock(&vnode->lock);
 90         }
 91 
 92         ret = 0;
 93 
 94         kunmap(page);
 95 out_free:
 96         page_cache_release(page);
 97 out:
 98         _leave(" = %d", ret);
 99         return ret;
100 }
101 
102 /*
103  * no valid lookup procedure on this sort of dir
104  */
105 static struct dentry *afs_mntpt_lookup(struct inode *dir,
106                                        struct dentry *dentry,
107                                        unsigned int flags)
108 {
109         _enter("%p,%p{%p{%s},%s}",
110                dir,
111                dentry,
112                dentry->d_parent,
113                dentry->d_parent ?
114                dentry->d_parent->d_name.name : (const unsigned char *) "",
115                dentry->d_name.name);
116 
117         return ERR_PTR(-EREMOTE);
118 }
119 
120 /*
121  * no valid open procedure on this sort of dir
122  */
123 static int afs_mntpt_open(struct inode *inode, struct file *file)
124 {
125         _enter("%p,%p{%p{%s},%s}",
126                inode, file,
127                file->f_path.dentry->d_parent,
128                file->f_path.dentry->d_parent ?
129                file->f_path.dentry->d_parent->d_name.name :
130                (const unsigned char *) "",
131                file->f_path.dentry->d_name.name);
132 
133         return -EREMOTE;
134 }
135 
136 /*
137  * create a vfsmount to be automounted
138  */
139 static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
140 {
141         struct afs_super_info *super;
142         struct vfsmount *mnt;
143         struct afs_vnode *vnode;
144         struct page *page;
145         char *devname, *options;
146         bool rwpath = false;
147         int ret;
148 
149         _enter("{%s}", mntpt->d_name.name);
150 
151         BUG_ON(!mntpt->d_inode);
152 
153         ret = -ENOMEM;
154         devname = (char *) get_zeroed_page(GFP_KERNEL);
155         if (!devname)
156                 goto error_no_devname;
157 
158         options = (char *) get_zeroed_page(GFP_KERNEL);
159         if (!options)
160                 goto error_no_options;
161 
162         vnode = AFS_FS_I(mntpt->d_inode);
163         if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
164                 /* if the directory is a pseudo directory, use the d_name */
165                 static const char afs_root_cell[] = ":root.cell.";
166                 unsigned size = mntpt->d_name.len;
167 
168                 ret = -ENOENT;
169                 if (size < 2 || size > AFS_MAXCELLNAME)
170                         goto error_no_page;
171 
172                 if (mntpt->d_name.name[0] == '.') {
173                         devname[0] = '#';
174                         memcpy(devname + 1, mntpt->d_name.name, size - 1);
175                         memcpy(devname + size, afs_root_cell,
176                                sizeof(afs_root_cell));
177                         rwpath = true;
178                 } else {
179                         devname[0] = '%';
180                         memcpy(devname + 1, mntpt->d_name.name, size);
181                         memcpy(devname + size + 1, afs_root_cell,
182                                sizeof(afs_root_cell));
183                 }
184         } else {
185                 /* read the contents of the AFS special symlink */
186                 loff_t size = i_size_read(mntpt->d_inode);
187                 char *buf;
188 
189                 ret = -EINVAL;
190                 if (size > PAGE_SIZE - 1)
191                         goto error_no_page;
192 
193                 page = read_mapping_page(mntpt->d_inode->i_mapping, 0, NULL);
194                 if (IS_ERR(page)) {
195                         ret = PTR_ERR(page);
196                         goto error_no_page;
197                 }
198 
199                 ret = -EIO;
200                 if (PageError(page))
201                         goto error;
202 
203                 buf = kmap_atomic(page);
204                 memcpy(devname, buf, size);
205                 kunmap_atomic(buf);
206                 page_cache_release(page);
207                 page = NULL;
208         }
209 
210         /* work out what options we want */
211         super = AFS_FS_S(mntpt->d_sb);
212         memcpy(options, "cell=", 5);
213         strcpy(options + 5, super->volume->cell->name);
214         if (super->volume->type == AFSVL_RWVOL || rwpath)
215                 strcat(options, ",rwpath");
216 
217         /* try and do the mount */
218         _debug("--- attempting mount %s -o %s ---", devname, options);
219         mnt = vfs_kern_mount(&afs_fs_type, 0, devname, options);
220         _debug("--- mount result %p ---", mnt);
221 
222         free_page((unsigned long) devname);
223         free_page((unsigned long) options);
224         _leave(" = %p", mnt);
225         return mnt;
226 
227 error:
228         page_cache_release(page);
229 error_no_page:
230         free_page((unsigned long) options);
231 error_no_options:
232         free_page((unsigned long) devname);
233 error_no_devname:
234         _leave(" = %d", ret);
235         return ERR_PTR(ret);
236 }
237 
238 /*
239  * handle an automount point
240  */
241 struct vfsmount *afs_d_automount(struct path *path)
242 {
243         struct vfsmount *newmnt;
244 
245         _enter("{%s}", path->dentry->d_name.name);
246 
247         newmnt = afs_mntpt_do_automount(path->dentry);
248         if (IS_ERR(newmnt))
249                 return newmnt;
250 
251         mntget(newmnt); /* prevent immediate expiration */
252         mnt_set_expiry(newmnt, &afs_vfsmounts);
253         queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
254                            afs_mntpt_expiry_timeout * HZ);
255         _leave(" = %p", newmnt);
256         return newmnt;
257 }
258 
259 /*
260  * handle mountpoint expiry timer going off
261  */
262 static void afs_mntpt_expiry_timed_out(struct work_struct *work)
263 {
264         _enter("");
265 
266         if (!list_empty(&afs_vfsmounts)) {
267                 mark_mounts_for_expiry(&afs_vfsmounts);
268                 queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
269                                    afs_mntpt_expiry_timeout * HZ);
270         }
271 
272         _leave("");
273 }
274 
275 /*
276  * kill the AFS mountpoint timer if it's still running
277  */
278 void afs_mntpt_kill_timer(void)
279 {
280         _enter("");
281 
282         ASSERT(list_empty(&afs_vfsmounts));
283         cancel_delayed_work_sync(&afs_mntpt_expiry_timer);
284 }
285 

~ [ 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