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>
25 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
27 static void afs_i_init_once(void *foo
, struct kmem_cache
*cachep
,
30 static int afs_get_sb(struct file_system_type
*fs_type
,
31 int flags
, const char *dev_name
,
32 void *data
, struct vfsmount
*mnt
);
34 static struct inode
*afs_alloc_inode(struct super_block
*sb
);
36 static void afs_put_super(struct super_block
*sb
);
38 static void afs_destroy_inode(struct inode
*inode
);
40 struct file_system_type afs_fs_type
= {
44 .kill_sb
= kill_anon_super
,
45 .fs_flags
= FS_BINARY_MOUNTDATA
,
48 static const struct super_operations afs_super_ops
= {
49 .statfs
= simple_statfs
,
50 .alloc_inode
= afs_alloc_inode
,
51 .drop_inode
= generic_delete_inode
,
52 .destroy_inode
= afs_destroy_inode
,
53 .clear_inode
= afs_clear_inode
,
54 .umount_begin
= afs_umount_begin
,
55 .put_super
= afs_put_super
,
58 static struct kmem_cache
*afs_inode_cachep
;
59 static atomic_t afs_count_active_inodes
;
62 * initialise the filesystem
64 int __init
afs_fs_init(void)
70 /* create ourselves an inode cache */
71 atomic_set(&afs_count_active_inodes
, 0);
74 afs_inode_cachep
= kmem_cache_create("afs_inode_cache",
75 sizeof(struct afs_vnode
),
80 if (!afs_inode_cachep
) {
81 printk(KERN_NOTICE
"kAFS: Failed to allocate inode cache\n");
85 /* now export our filesystem to lesser mortals */
86 ret
= register_filesystem(&afs_fs_type
);
88 kmem_cache_destroy(afs_inode_cachep
);
98 * clean up the filesystem
100 void __exit
afs_fs_exit(void)
104 afs_mntpt_kill_timer();
105 unregister_filesystem(&afs_fs_type
);
107 if (atomic_read(&afs_count_active_inodes
) != 0) {
108 printk("kAFS: %d active inode objects still present\n",
109 atomic_read(&afs_count_active_inodes
));
113 kmem_cache_destroy(afs_inode_cachep
);
118 * check that an argument has a value
120 static int want_arg(char **_value
, const char *option
)
122 if (!_value
|| !*_value
|| !**_value
) {
123 printk(KERN_NOTICE
"kAFS: %s: argument missing\n", option
);
130 * check that there's no subsequent value
132 static int want_no_value(char *const *_value
, const char *option
)
134 if (*_value
&& **_value
) {
135 printk(KERN_NOTICE
"kAFS: %s: Invalid argument: %s\n",
143 * parse the mount options
144 * - this function has been shamelessly adapted from the ext3 fs which
145 * shamelessly adapted it from the msdos fs
147 static int afs_parse_options(struct afs_mount_params
*params
,
148 char *options
, const char **devname
)
150 struct afs_cell
*cell
;
154 _enter("%s", options
);
156 options
[PAGE_SIZE
- 1] = 0;
159 while ((key
= strsep(&options
, ","))) {
160 value
= strchr(key
, '=');
164 _debug("kAFS: KEY: %s, VAL:%s", key
, value
?: "-");
166 if (strcmp(key
, "rwpath") == 0) {
167 if (!want_no_value(&value
, "rwpath"))
170 } else if (strcmp(key
, "vol") == 0) {
171 if (!want_arg(&value
, "vol"))
174 } else if (strcmp(key
, "cell") == 0) {
175 if (!want_arg(&value
, "cell"))
177 cell
= afs_cell_lookup(value
, strlen(value
));
179 return PTR_ERR(cell
);
180 afs_put_cell(params
->cell
);
183 printk("kAFS: Unknown mount option: '%s'\n", key
);
191 _leave(" = %d", ret
);
196 * parse a device name to get cell name, volume name, volume type and R/W
198 * - this can be one of the following:
199 * "%[cell:]volume[.]" R/W volume
200 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
201 * or R/W (rwpath=1) volume
202 * "%[cell:]volume.readonly" R/O volume
203 * "#[cell:]volume.readonly" R/O volume
204 * "%[cell:]volume.backup" Backup volume
205 * "#[cell:]volume.backup" Backup volume
207 static int afs_parse_device_name(struct afs_mount_params
*params
,
210 struct afs_cell
*cell
;
211 const char *cellname
, *suffix
;
217 printk(KERN_ERR
"kAFS: no volume name specified\n");
221 if ((name
[0] != '%' && name
[0] != '#') || !name
[1]) {
222 printk(KERN_ERR
"kAFS: unparsable volume name\n");
226 /* determine the type of volume we're looking for */
227 params
->type
= AFSVL_ROVOL
;
228 params
->force
= false;
229 if (params
->rwpath
|| name
[0] == '%') {
230 params
->type
= AFSVL_RWVOL
;
231 params
->force
= true;
235 /* split the cell name out if there is one */
236 params
->volname
= strchr(name
, ':');
237 if (params
->volname
) {
239 cellnamesz
= params
->volname
- name
;
242 params
->volname
= name
;
247 /* the volume type is further affected by a possible suffix */
248 suffix
= strrchr(params
->volname
, '.');
250 if (strcmp(suffix
, ".readonly") == 0) {
251 params
->type
= AFSVL_ROVOL
;
252 params
->force
= true;
253 } else if (strcmp(suffix
, ".backup") == 0) {
254 params
->type
= AFSVL_BACKVOL
;
255 params
->force
= true;
256 } else if (suffix
[1] == 0) {
262 params
->volnamesz
= suffix
?
263 suffix
- params
->volname
: strlen(params
->volname
);
265 _debug("cell %*.*s [%p]",
266 cellnamesz
, cellnamesz
, cellname
?: "", params
->cell
);
268 /* lookup the cell record */
269 if (cellname
|| !params
->cell
) {
270 cell
= afs_cell_lookup(cellname
, cellnamesz
);
272 printk(KERN_ERR
"kAFS: unable to lookup cell '%s'\n",
274 return PTR_ERR(cell
);
276 afs_put_cell(params
->cell
);
280 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
281 params
->cell
->name
, params
->cell
,
282 params
->volnamesz
, params
->volnamesz
, params
->volname
,
283 suffix
?: "-", params
->type
, params
->force
? " FORCE" : "");
289 * check a superblock to see if it's the one we're looking for
291 static int afs_test_super(struct super_block
*sb
, void *data
)
293 struct afs_mount_params
*params
= data
;
294 struct afs_super_info
*as
= sb
->s_fs_info
;
296 return as
->volume
== params
->volume
;
300 * fill in the superblock
302 static int afs_fill_super(struct super_block
*sb
, void *data
)
304 struct afs_mount_params
*params
= data
;
305 struct afs_super_info
*as
= NULL
;
307 struct dentry
*root
= NULL
;
308 struct inode
*inode
= NULL
;
313 /* allocate a superblock info record */
314 as
= kzalloc(sizeof(struct afs_super_info
), GFP_KERNEL
);
316 _leave(" = -ENOMEM");
320 afs_get_volume(params
->volume
);
321 as
->volume
= params
->volume
;
323 /* fill in the superblock */
324 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
325 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
326 sb
->s_magic
= AFS_FS_MAGIC
;
327 sb
->s_op
= &afs_super_ops
;
330 /* allocate the root inode and dentry */
331 fid
.vid
= as
->volume
->vid
;
334 inode
= afs_iget(sb
, params
->key
, &fid
, NULL
, NULL
);
339 root
= d_alloc_root(inode
);
349 ret
= PTR_ERR(inode
);
353 afs_put_volume(as
->volume
);
356 sb
->s_fs_info
= NULL
;
358 _leave(" = %d", ret
);
363 * get an AFS superblock
364 * - TODO: don't use get_sb_nodev(), but rather call sget() directly
366 static int afs_get_sb(struct file_system_type
*fs_type
,
368 const char *dev_name
,
370 struct vfsmount
*mnt
)
372 struct afs_mount_params params
;
373 struct super_block
*sb
;
374 struct afs_volume
*vol
;
378 _enter(",,%s,%p", dev_name
, options
);
380 memset(¶ms
, 0, sizeof(params
));
382 /* parse the options and device name */
384 ret
= afs_parse_options(¶ms
, options
, &dev_name
);
390 ret
= afs_parse_device_name(¶ms
, dev_name
);
394 /* try and do the mount securely */
395 key
= afs_request_key(params
.cell
);
397 _leave(" = %ld [key]", PTR_ERR(key
));
403 /* parse the device name */
404 vol
= afs_volume_lookup(¶ms
);
411 /* allocate a deviceless superblock */
412 sb
= sget(fs_type
, afs_test_super
, set_anon_super
, ¶ms
);
419 /* initial superblock/root creation */
422 ret
= afs_fill_super(sb
, ¶ms
);
424 up_write(&sb
->s_umount
);
425 deactivate_super(sb
);
428 sb
->s_flags
|= MS_ACTIVE
;
431 ASSERTCMP(sb
->s_flags
, &, MS_ACTIVE
);
434 simple_set_mnt(mnt
, sb
);
435 afs_put_volume(params
.volume
);
436 afs_put_cell(params
.cell
);
437 _leave(" = 0 [%p]", sb
);
441 afs_put_volume(params
.volume
);
442 afs_put_cell(params
.cell
);
444 _leave(" = %d", ret
);
449 * finish the unmounting process on the superblock
451 static void afs_put_super(struct super_block
*sb
)
453 struct afs_super_info
*as
= sb
->s_fs_info
;
457 afs_put_volume(as
->volume
);
463 * initialise an inode cache slab element prior to any use
465 static void afs_i_init_once(void *_vnode
, struct kmem_cache
*cachep
,
468 struct afs_vnode
*vnode
= _vnode
;
470 if ((flags
& (SLAB_CTOR_VERIFY
|SLAB_CTOR_CONSTRUCTOR
)) ==
471 SLAB_CTOR_CONSTRUCTOR
) {
472 memset(vnode
, 0, sizeof(*vnode
));
473 inode_init_once(&vnode
->vfs_inode
);
474 init_waitqueue_head(&vnode
->update_waitq
);
475 mutex_init(&vnode
->permits_lock
);
476 mutex_init(&vnode
->validate_lock
);
477 spin_lock_init(&vnode
->lock
);
478 INIT_WORK(&vnode
->cb_broken_work
, afs_broken_callback_work
);
483 * allocate an AFS inode struct from our slab cache
485 static struct inode
*afs_alloc_inode(struct super_block
*sb
)
487 struct afs_vnode
*vnode
;
489 vnode
= kmem_cache_alloc(afs_inode_cachep
, GFP_KERNEL
);
493 atomic_inc(&afs_count_active_inodes
);
495 memset(&vnode
->fid
, 0, sizeof(vnode
->fid
));
496 memset(&vnode
->status
, 0, sizeof(vnode
->status
));
498 vnode
->volume
= NULL
;
499 vnode
->update_cnt
= 0;
500 vnode
->flags
= 1 << AFS_VNODE_UNSET
;
501 vnode
->cb_promised
= false;
503 return &vnode
->vfs_inode
;
507 * destroy an AFS inode struct
509 static void afs_destroy_inode(struct inode
*inode
)
511 struct afs_vnode
*vnode
= AFS_FS_I(inode
);
513 _enter("{%lu}", inode
->i_ino
);
515 _debug("DESTROY INODE %p", inode
);
517 ASSERTCMP(vnode
->server
, ==, NULL
);
519 kmem_cache_free(afs_inode_cachep
, vnode
);
520 atomic_dec(&afs_count_active_inodes
);