1 /* AFS superblock handling
3 * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
5 * This software may be freely redistributed under the terms of the
6 * GNU General Public License.
8 * You should have received a copy of the GNU General Public License
9 * along with this program; if not, write to the Free Software
10 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
12 * Authors: David Howells <dhowells@redhat.com>
13 * David Woodhouse <dwmw2@redhat.com>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/slab.h>
22 #include <linux/pagemap.h>
23 #include <linux/parser.h>
26 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
28 static void afs_i_init_once(void *foo, struct kmem_cache *cachep,
31 static int afs_get_sb(struct file_system_type *fs_type,
32 int flags, const char *dev_name,
33 void *data, struct vfsmount *mnt);
35 static struct inode *afs_alloc_inode(struct super_block *sb);
37 static void afs_put_super(struct super_block *sb);
39 static void afs_destroy_inode(struct inode *inode);
41 struct file_system_type afs_fs_type = {
45 .kill_sb = kill_anon_super,
49 static const struct super_operations afs_super_ops = {
50 .statfs = simple_statfs,
51 .alloc_inode = afs_alloc_inode,
52 .drop_inode = generic_delete_inode,
53 .destroy_inode = afs_destroy_inode,
54 .clear_inode = afs_clear_inode,
55 .umount_begin = afs_umount_begin,
56 .put_super = afs_put_super,
59 static struct kmem_cache *afs_inode_cachep;
60 static atomic_t afs_count_active_inodes;
69 static const match_table_t afs_options_list = {
70 { afs_opt_cell, "cell=%s" },
71 { afs_opt_rwpath, "rwpath" },
72 { afs_opt_vol, "vol=%s" },
77 * initialise the filesystem
79 int __init afs_fs_init(void)
85 /* create ourselves an inode cache */
86 atomic_set(&afs_count_active_inodes, 0);
89 afs_inode_cachep = kmem_cache_create("afs_inode_cache",
90 sizeof(struct afs_vnode),
95 if (!afs_inode_cachep) {
96 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
100 /* now export our filesystem to lesser mortals */
101 ret = register_filesystem(&afs_fs_type);
103 kmem_cache_destroy(afs_inode_cachep);
104 _leave(" = %d", ret);
113 * clean up the filesystem
115 void __exit afs_fs_exit(void)
119 afs_mntpt_kill_timer();
120 unregister_filesystem(&afs_fs_type);
122 if (atomic_read(&afs_count_active_inodes) != 0) {
123 printk("kAFS: %d active inode objects still present\n",
124 atomic_read(&afs_count_active_inodes));
128 kmem_cache_destroy(afs_inode_cachep);
133 * parse the mount options
134 * - this function has been shamelessly adapted from the ext3 fs which
135 * shamelessly adapted it from the msdos fs
137 static int afs_parse_options(struct afs_mount_params *params,
138 char *options, const char **devname)
140 struct afs_cell *cell;
141 substring_t args[MAX_OPT_ARGS];
145 _enter("%s", options);
147 options[PAGE_SIZE - 1] = 0;
149 while ((p = strsep(&options, ","))) {
153 token = match_token(p, afs_options_list, args);
156 cell = afs_cell_lookup(args[0].from,
157 args[0].to - args[0].from);
159 return PTR_ERR(cell);
160 afs_put_cell(params->cell);
169 *devname = args[0].from;
173 printk(KERN_ERR "kAFS:"
174 " Unknown or invalid mount option: '%s'\n", p);
184 * parse a device name to get cell name, volume name, volume type and R/W
186 * - this can be one of the following:
187 * "%[cell:]volume[.]" R/W volume
188 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
189 * or R/W (rwpath=1) volume
190 * "%[cell:]volume.readonly" R/O volume
191 * "#[cell:]volume.readonly" R/O volume
192 * "%[cell:]volume.backup" Backup volume
193 * "#[cell:]volume.backup" Backup volume
195 static int afs_parse_device_name(struct afs_mount_params *params,
198 struct afs_cell *cell;
199 const char *cellname, *suffix;
205 printk(KERN_ERR "kAFS: no volume name specified\n");
209 if ((name[0] != '%' && name[0] != '#') || !name[1]) {
210 printk(KERN_ERR "kAFS: unparsable volume name\n");
214 /* determine the type of volume we're looking for */
215 params->type = AFSVL_ROVOL;
216 params->force = false;
217 if (params->rwpath || name[0] == '%') {
218 params->type = AFSVL_RWVOL;
219 params->force = true;
223 /* split the cell name out if there is one */
224 params->volname = strchr(name, ':');
225 if (params->volname) {
227 cellnamesz = params->volname - name;
230 params->volname = name;
235 /* the volume type is further affected by a possible suffix */
236 suffix = strrchr(params->volname, '.');
238 if (strcmp(suffix, ".readonly") == 0) {
239 params->type = AFSVL_ROVOL;
240 params->force = true;
241 } else if (strcmp(suffix, ".backup") == 0) {
242 params->type = AFSVL_BACKVOL;
243 params->force = true;
244 } else if (suffix[1] == 0) {
250 params->volnamesz = suffix ?
251 suffix - params->volname : strlen(params->volname);
253 _debug("cell %*.*s [%p]",
254 cellnamesz, cellnamesz, cellname ?: "", params->cell);
256 /* lookup the cell record */
257 if (cellname || !params->cell) {
258 cell = afs_cell_lookup(cellname, cellnamesz);
260 printk(KERN_ERR "kAFS: unable to lookup cell '%s'\n",
262 return PTR_ERR(cell);
264 afs_put_cell(params->cell);
268 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
269 params->cell->name, params->cell,
270 params->volnamesz, params->volnamesz, params->volname,
271 suffix ?: "-", params->type, params->force ? " FORCE" : "");
277 * check a superblock to see if it's the one we're looking for
279 static int afs_test_super(struct super_block *sb, void *data)
281 struct afs_mount_params *params = data;
282 struct afs_super_info *as = sb->s_fs_info;
284 return as->volume == params->volume;
288 * fill in the superblock
290 static int afs_fill_super(struct super_block *sb, void *data)
292 struct afs_mount_params *params = data;
293 struct afs_super_info *as = NULL;
295 struct dentry *root = NULL;
296 struct inode *inode = NULL;
301 /* allocate a superblock info record */
302 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
304 _leave(" = -ENOMEM");
308 afs_get_volume(params->volume);
309 as->volume = params->volume;
311 /* fill in the superblock */
312 sb->s_blocksize = PAGE_CACHE_SIZE;
313 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
314 sb->s_magic = AFS_FS_MAGIC;
315 sb->s_op = &afs_super_ops;
318 /* allocate the root inode and dentry */
319 fid.vid = as->volume->vid;
322 inode = afs_iget(sb, params->key, &fid, NULL, NULL);
327 root = d_alloc_root(inode);
337 ret = PTR_ERR(inode);
341 afs_put_volume(as->volume);
344 sb->s_fs_info = NULL;
346 _leave(" = %d", ret);
351 * get an AFS superblock
353 static int afs_get_sb(struct file_system_type *fs_type,
355 const char *dev_name,
357 struct vfsmount *mnt)
359 struct afs_mount_params params;
360 struct super_block *sb;
361 struct afs_volume *vol;
365 _enter(",,%s,%p", dev_name, options);
367 memset(¶ms, 0, sizeof(params));
369 /* parse the options and device name */
371 ret = afs_parse_options(¶ms, options, &dev_name);
376 ret = afs_parse_device_name(¶ms, dev_name);
380 /* try and do the mount securely */
381 key = afs_request_key(params.cell);
383 _leave(" = %ld [key]", PTR_ERR(key));
389 /* parse the device name */
390 vol = afs_volume_lookup(¶ms);
397 /* allocate a deviceless superblock */
398 sb = sget(fs_type, afs_test_super, set_anon_super, ¶ms);
405 /* initial superblock/root creation */
408 ret = afs_fill_super(sb, ¶ms);
410 up_write(&sb->s_umount);
411 deactivate_super(sb);
414 sb->s_flags |= MS_ACTIVE;
417 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
420 simple_set_mnt(mnt, sb);
421 afs_put_volume(params.volume);
422 afs_put_cell(params.cell);
423 _leave(" = 0 [%p]", sb);
427 afs_put_volume(params.volume);
428 afs_put_cell(params.cell);
430 _leave(" = %d", ret);
435 * finish the unmounting process on the superblock
437 static void afs_put_super(struct super_block *sb)
439 struct afs_super_info *as = sb->s_fs_info;
443 afs_put_volume(as->volume);
449 * initialise an inode cache slab element prior to any use
451 static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep,
454 struct afs_vnode *vnode = _vnode;
456 if (flags & SLAB_CTOR_CONSTRUCTOR) {
457 memset(vnode, 0, sizeof(*vnode));
458 inode_init_once(&vnode->vfs_inode);
459 init_waitqueue_head(&vnode->update_waitq);
460 mutex_init(&vnode->permits_lock);
461 mutex_init(&vnode->validate_lock);
462 spin_lock_init(&vnode->lock);
463 INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
468 * allocate an AFS inode struct from our slab cache
470 static struct inode *afs_alloc_inode(struct super_block *sb)
472 struct afs_vnode *vnode;
474 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
478 atomic_inc(&afs_count_active_inodes);
480 memset(&vnode->fid, 0, sizeof(vnode->fid));
481 memset(&vnode->status, 0, sizeof(vnode->status));
483 vnode->volume = NULL;
484 vnode->update_cnt = 0;
485 vnode->flags = 1 << AFS_VNODE_UNSET;
486 vnode->cb_promised = false;
488 return &vnode->vfs_inode;
492 * destroy an AFS inode struct
494 static void afs_destroy_inode(struct inode *inode)
496 struct afs_vnode *vnode = AFS_FS_I(inode);
498 _enter("{%lu}", inode->i_ino);
500 _debug("DESTROY INODE %p", inode);
502 ASSERTCMP(vnode->server, ==, NULL);
504 kmem_cache_free(afs_inode_cachep, vnode);
505 atomic_dec(&afs_count_active_inodes);