Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/drivers/block/loop.c | |
3 | * | |
4 | * Written by Theodore Ts'o, 3/29/93 | |
5 | * | |
6 | * Copyright 1993 by Theodore Ts'o. Redistribution of this file is | |
7 | * permitted under the GNU General Public License. | |
8 | * | |
9 | * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993 | |
10 | * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996 | |
11 | * | |
12 | * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994 | |
13 | * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996 | |
14 | * | |
15 | * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997 | |
16 | * | |
17 | * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998 | |
18 | * | |
19 | * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998 | |
20 | * | |
21 | * Loadable modules and other fixes by AK, 1998 | |
22 | * | |
23 | * Make real block number available to downstream transfer functions, enables | |
24 | * CBC (and relatives) mode encryption requiring unique IVs per data block. | |
25 | * Reed H. Petty, rhp@draper.net | |
26 | * | |
27 | * Maximum number of loop devices now dynamic via max_loop module parameter. | |
28 | * Russell Kroll <rkroll@exploits.org> 19990701 | |
29 | * | |
30 | * Maximum number of loop devices when compiled-in now selectable by passing | |
31 | * max_loop=<1-255> to the kernel on boot. | |
96de0e25 | 32 | * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999 |
1da177e4 LT |
33 | * |
34 | * Completely rewrite request handling to be make_request_fn style and | |
35 | * non blocking, pushing work to a helper thread. Lots of fixes from | |
36 | * Al Viro too. | |
37 | * Jens Axboe <axboe@suse.de>, Nov 2000 | |
38 | * | |
39 | * Support up to 256 loop devices | |
40 | * Heinz Mauelshagen <mge@sistina.com>, Feb 2002 | |
41 | * | |
42 | * Support for falling back on the write file operation when the address space | |
4e02ed4b | 43 | * operations write_begin is not available on the backing filesystem. |
1da177e4 LT |
44 | * Anton Altaparmakov, 16 Feb 2005 |
45 | * | |
46 | * Still To Fix: | |
47 | * - Advisory locking is ignored here. | |
48 | * - Should use an own CAP_* category instead of CAP_SYS_ADMIN | |
49 | * | |
50 | */ | |
51 | ||
1da177e4 LT |
52 | #include <linux/module.h> |
53 | #include <linux/moduleparam.h> | |
54 | #include <linux/sched.h> | |
55 | #include <linux/fs.h> | |
56 | #include <linux/file.h> | |
57 | #include <linux/stat.h> | |
58 | #include <linux/errno.h> | |
59 | #include <linux/major.h> | |
60 | #include <linux/wait.h> | |
61 | #include <linux/blkdev.h> | |
62 | #include <linux/blkpg.h> | |
63 | #include <linux/init.h> | |
1da177e4 LT |
64 | #include <linux/swap.h> |
65 | #include <linux/slab.h> | |
66 | #include <linux/loop.h> | |
863d5b82 | 67 | #include <linux/compat.h> |
1da177e4 | 68 | #include <linux/suspend.h> |
83144186 | 69 | #include <linux/freezer.h> |
2a48fc0a | 70 | #include <linux/mutex.h> |
1da177e4 | 71 | #include <linux/writeback.h> |
1da177e4 LT |
72 | #include <linux/completion.h> |
73 | #include <linux/highmem.h> | |
6c997918 | 74 | #include <linux/kthread.h> |
d6b29d7c | 75 | #include <linux/splice.h> |
ee862730 | 76 | #include <linux/sysfs.h> |
770fe30a | 77 | #include <linux/miscdevice.h> |
dfaa2ef6 | 78 | #include <linux/falloc.h> |
1da177e4 LT |
79 | |
80 | #include <asm/uaccess.h> | |
81 | ||
34dd82af KS |
82 | static DEFINE_IDR(loop_index_idr); |
83 | static DEFINE_MUTEX(loop_index_mutex); | |
1da177e4 | 84 | |
476a4813 LV |
85 | static int max_part; |
86 | static int part_shift; | |
87 | ||
1da177e4 LT |
88 | /* |
89 | * Transfer functions | |
90 | */ | |
91 | static int transfer_none(struct loop_device *lo, int cmd, | |
92 | struct page *raw_page, unsigned raw_off, | |
93 | struct page *loop_page, unsigned loop_off, | |
94 | int size, sector_t real_block) | |
95 | { | |
cfd8005c CW |
96 | char *raw_buf = kmap_atomic(raw_page) + raw_off; |
97 | char *loop_buf = kmap_atomic(loop_page) + loop_off; | |
1da177e4 LT |
98 | |
99 | if (cmd == READ) | |
100 | memcpy(loop_buf, raw_buf, size); | |
101 | else | |
102 | memcpy(raw_buf, loop_buf, size); | |
103 | ||
cfd8005c CW |
104 | kunmap_atomic(loop_buf); |
105 | kunmap_atomic(raw_buf); | |
1da177e4 LT |
106 | cond_resched(); |
107 | return 0; | |
108 | } | |
109 | ||
110 | static int transfer_xor(struct loop_device *lo, int cmd, | |
111 | struct page *raw_page, unsigned raw_off, | |
112 | struct page *loop_page, unsigned loop_off, | |
113 | int size, sector_t real_block) | |
114 | { | |
cfd8005c CW |
115 | char *raw_buf = kmap_atomic(raw_page) + raw_off; |
116 | char *loop_buf = kmap_atomic(loop_page) + loop_off; | |
1da177e4 LT |
117 | char *in, *out, *key; |
118 | int i, keysize; | |
119 | ||
120 | if (cmd == READ) { | |
121 | in = raw_buf; | |
122 | out = loop_buf; | |
123 | } else { | |
124 | in = loop_buf; | |
125 | out = raw_buf; | |
126 | } | |
127 | ||
128 | key = lo->lo_encrypt_key; | |
129 | keysize = lo->lo_encrypt_key_size; | |
130 | for (i = 0; i < size; i++) | |
131 | *out++ = *in++ ^ key[(i & 511) % keysize]; | |
132 | ||
cfd8005c CW |
133 | kunmap_atomic(loop_buf); |
134 | kunmap_atomic(raw_buf); | |
1da177e4 LT |
135 | cond_resched(); |
136 | return 0; | |
137 | } | |
138 | ||
139 | static int xor_init(struct loop_device *lo, const struct loop_info64 *info) | |
140 | { | |
141 | if (unlikely(info->lo_encrypt_key_size <= 0)) | |
142 | return -EINVAL; | |
143 | return 0; | |
144 | } | |
145 | ||
146 | static struct loop_func_table none_funcs = { | |
147 | .number = LO_CRYPT_NONE, | |
148 | .transfer = transfer_none, | |
149 | }; | |
150 | ||
151 | static struct loop_func_table xor_funcs = { | |
152 | .number = LO_CRYPT_XOR, | |
153 | .transfer = transfer_xor, | |
154 | .init = xor_init | |
155 | }; | |
156 | ||
157 | /* xfer_funcs[0] is special - its release function is never called */ | |
158 | static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { | |
159 | &none_funcs, | |
160 | &xor_funcs | |
161 | }; | |
162 | ||
7035b5df | 163 | static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) |
1da177e4 | 164 | { |
7035b5df | 165 | loff_t size, loopsize; |
1da177e4 LT |
166 | |
167 | /* Compute loopsize in bytes */ | |
168 | size = i_size_read(file->f_mapping->host); | |
1da177e4 | 169 | loopsize = size - offset; |
7035b5df DM |
170 | /* offset is beyond i_size, wierd but possible */ |
171 | if (loopsize < 0) | |
172 | return 0; | |
1da177e4 | 173 | |
7035b5df DM |
174 | if (sizelimit > 0 && sizelimit < loopsize) |
175 | loopsize = sizelimit; | |
1da177e4 LT |
176 | /* |
177 | * Unfortunately, if we want to do I/O on the device, | |
178 | * the number of 512-byte sectors has to fit into a sector_t. | |
179 | */ | |
180 | return loopsize >> 9; | |
181 | } | |
182 | ||
7035b5df DM |
183 | static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
184 | { | |
185 | return get_size(lo->lo_offset, lo->lo_sizelimit, file); | |
186 | } | |
187 | ||
1da177e4 | 188 | static int |
7035b5df | 189 | figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) |
1da177e4 | 190 | { |
7035b5df | 191 | loff_t size = get_size(offset, sizelimit, lo->lo_backing_file); |
1da177e4 | 192 | sector_t x = (sector_t)size; |
7b0576a3 | 193 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
194 | |
195 | if (unlikely((loff_t)x != size)) | |
196 | return -EFBIG; | |
7035b5df DM |
197 | if (lo->lo_offset != offset) |
198 | lo->lo_offset = offset; | |
199 | if (lo->lo_sizelimit != sizelimit) | |
200 | lo->lo_sizelimit = sizelimit; | |
73285082 | 201 | set_capacity(lo->lo_disk, x); |
7b0576a3 GC |
202 | bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9); |
203 | /* let user-space know about the new size */ | |
204 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
7035b5df | 205 | return 0; |
1da177e4 LT |
206 | } |
207 | ||
208 | static inline int | |
209 | lo_do_transfer(struct loop_device *lo, int cmd, | |
210 | struct page *rpage, unsigned roffs, | |
211 | struct page *lpage, unsigned loffs, | |
212 | int size, sector_t rblock) | |
213 | { | |
214 | if (unlikely(!lo->transfer)) | |
215 | return 0; | |
216 | ||
217 | return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); | |
218 | } | |
219 | ||
1da177e4 LT |
220 | /** |
221 | * __do_lo_send_write - helper for writing data to a loop device | |
222 | * | |
223 | * This helper just factors out common code between do_lo_send_direct_write() | |
224 | * and do_lo_send_write(). | |
225 | */ | |
858119e1 | 226 | static int __do_lo_send_write(struct file *file, |
98ae6ccd | 227 | u8 *buf, const int len, loff_t pos) |
1da177e4 LT |
228 | { |
229 | ssize_t bw; | |
230 | mm_segment_t old_fs = get_fs(); | |
231 | ||
232 | set_fs(get_ds()); | |
233 | bw = file->f_op->write(file, buf, len, &pos); | |
234 | set_fs(old_fs); | |
235 | if (likely(bw == len)) | |
236 | return 0; | |
237 | printk(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", | |
238 | (unsigned long long)pos, len); | |
239 | if (bw >= 0) | |
240 | bw = -EIO; | |
241 | return bw; | |
242 | } | |
243 | ||
244 | /** | |
245 | * do_lo_send_direct_write - helper for writing data to a loop device | |
246 | * | |
456be148 CH |
247 | * This is the fast, non-transforming version that does not need double |
248 | * buffering. | |
1da177e4 LT |
249 | */ |
250 | static int do_lo_send_direct_write(struct loop_device *lo, | |
511de73f | 251 | struct bio_vec *bvec, loff_t pos, struct page *page) |
1da177e4 LT |
252 | { |
253 | ssize_t bw = __do_lo_send_write(lo->lo_backing_file, | |
98ae6ccd | 254 | kmap(bvec->bv_page) + bvec->bv_offset, |
1da177e4 LT |
255 | bvec->bv_len, pos); |
256 | kunmap(bvec->bv_page); | |
257 | cond_resched(); | |
258 | return bw; | |
259 | } | |
260 | ||
261 | /** | |
262 | * do_lo_send_write - helper for writing data to a loop device | |
263 | * | |
456be148 CH |
264 | * This is the slow, transforming version that needs to double buffer the |
265 | * data as it cannot do the transformations in place without having direct | |
266 | * access to the destination pages of the backing file. | |
1da177e4 LT |
267 | */ |
268 | static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, | |
511de73f | 269 | loff_t pos, struct page *page) |
1da177e4 LT |
270 | { |
271 | int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, | |
272 | bvec->bv_offset, bvec->bv_len, pos >> 9); | |
273 | if (likely(!ret)) | |
274 | return __do_lo_send_write(lo->lo_backing_file, | |
98ae6ccd | 275 | page_address(page), bvec->bv_len, |
1da177e4 LT |
276 | pos); |
277 | printk(KERN_ERR "loop: Transfer error at byte offset %llu, " | |
278 | "length %i.\n", (unsigned long long)pos, bvec->bv_len); | |
279 | if (ret > 0) | |
280 | ret = -EIO; | |
281 | return ret; | |
282 | } | |
283 | ||
511de73f | 284 | static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos) |
1da177e4 | 285 | { |
511de73f | 286 | int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t, |
1da177e4 LT |
287 | struct page *page); |
288 | struct bio_vec *bvec; | |
289 | struct page *page = NULL; | |
290 | int i, ret = 0; | |
291 | ||
456be148 CH |
292 | if (lo->transfer != transfer_none) { |
293 | page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); | |
294 | if (unlikely(!page)) | |
295 | goto fail; | |
296 | kmap(page); | |
297 | do_lo_send = do_lo_send_write; | |
298 | } else { | |
1da177e4 | 299 | do_lo_send = do_lo_send_direct_write; |
1da177e4 | 300 | } |
456be148 | 301 | |
1da177e4 | 302 | bio_for_each_segment(bvec, bio, i) { |
511de73f | 303 | ret = do_lo_send(lo, bvec, pos, page); |
1da177e4 LT |
304 | if (ret < 0) |
305 | break; | |
306 | pos += bvec->bv_len; | |
307 | } | |
308 | if (page) { | |
309 | kunmap(page); | |
310 | __free_page(page); | |
311 | } | |
312 | out: | |
313 | return ret; | |
314 | fail: | |
315 | printk(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); | |
316 | ret = -ENOMEM; | |
317 | goto out; | |
318 | } | |
319 | ||
320 | struct lo_read_data { | |
321 | struct loop_device *lo; | |
322 | struct page *page; | |
323 | unsigned offset; | |
324 | int bsize; | |
325 | }; | |
326 | ||
327 | static int | |
fd582140 JA |
328 | lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
329 | struct splice_desc *sd) | |
1da177e4 | 330 | { |
fd582140 | 331 | struct lo_read_data *p = sd->u.data; |
1da177e4 | 332 | struct loop_device *lo = p->lo; |
fd582140 | 333 | struct page *page = buf->page; |
1da177e4 | 334 | sector_t IV; |
3603b8ea | 335 | int size; |
1da177e4 | 336 | |
fd582140 JA |
337 | IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) + |
338 | (buf->offset >> 9); | |
339 | size = sd->len; | |
340 | if (size > p->bsize) | |
341 | size = p->bsize; | |
1da177e4 | 342 | |
fd582140 | 343 | if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) { |
1da177e4 LT |
344 | printk(KERN_ERR "loop: transfer error block %ld\n", |
345 | page->index); | |
fd582140 | 346 | size = -EINVAL; |
1da177e4 LT |
347 | } |
348 | ||
349 | flush_dcache_page(p->page); | |
350 | ||
fd582140 JA |
351 | if (size > 0) |
352 | p->offset += size; | |
353 | ||
1da177e4 LT |
354 | return size; |
355 | } | |
356 | ||
fd582140 JA |
357 | static int |
358 | lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) | |
359 | { | |
360 | return __splice_from_pipe(pipe, sd, lo_splice_actor); | |
361 | } | |
362 | ||
306df071 | 363 | static ssize_t |
1da177e4 LT |
364 | do_lo_receive(struct loop_device *lo, |
365 | struct bio_vec *bvec, int bsize, loff_t pos) | |
366 | { | |
367 | struct lo_read_data cookie; | |
fd582140 | 368 | struct splice_desc sd; |
1da177e4 | 369 | struct file *file; |
306df071 | 370 | ssize_t retval; |
1da177e4 LT |
371 | |
372 | cookie.lo = lo; | |
373 | cookie.page = bvec->bv_page; | |
374 | cookie.offset = bvec->bv_offset; | |
375 | cookie.bsize = bsize; | |
fd582140 JA |
376 | |
377 | sd.len = 0; | |
378 | sd.total_len = bvec->bv_len; | |
379 | sd.flags = 0; | |
380 | sd.pos = pos; | |
381 | sd.u.data = &cookie; | |
382 | ||
1da177e4 | 383 | file = lo->lo_backing_file; |
fd582140 JA |
384 | retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor); |
385 | ||
306df071 | 386 | return retval; |
1da177e4 LT |
387 | } |
388 | ||
389 | static int | |
390 | lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos) | |
391 | { | |
392 | struct bio_vec *bvec; | |
306df071 DY |
393 | ssize_t s; |
394 | int i; | |
1da177e4 LT |
395 | |
396 | bio_for_each_segment(bvec, bio, i) { | |
306df071 DY |
397 | s = do_lo_receive(lo, bvec, bsize, pos); |
398 | if (s < 0) | |
399 | return s; | |
400 | ||
401 | if (s != bvec->bv_len) { | |
402 | zero_fill_bio(bio); | |
1da177e4 | 403 | break; |
306df071 | 404 | } |
1da177e4 LT |
405 | pos += bvec->bv_len; |
406 | } | |
306df071 | 407 | return 0; |
1da177e4 LT |
408 | } |
409 | ||
410 | static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) | |
411 | { | |
412 | loff_t pos; | |
413 | int ret; | |
414 | ||
415 | pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; | |
68db1961 NK |
416 | |
417 | if (bio_rw(bio) == WRITE) { | |
68db1961 NK |
418 | struct file *file = lo->lo_backing_file; |
419 | ||
6259f284 | 420 | if (bio->bi_rw & REQ_FLUSH) { |
8018ab05 | 421 | ret = vfs_fsync(file, 0); |
6259f284 | 422 | if (unlikely(ret && ret != -EINVAL)) { |
68db1961 NK |
423 | ret = -EIO; |
424 | goto out; | |
425 | } | |
426 | } | |
427 | ||
dfaa2ef6 LC |
428 | /* |
429 | * We use punch hole to reclaim the free space used by the | |
ae95757a | 430 | * image a.k.a. discard. However we do not support discard if |
dfaa2ef6 LC |
431 | * encryption is enabled, because it may give an attacker |
432 | * useful information. | |
433 | */ | |
434 | if (bio->bi_rw & REQ_DISCARD) { | |
435 | struct file *file = lo->lo_backing_file; | |
436 | int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE; | |
437 | ||
438 | if ((!file->f_op->fallocate) || | |
439 | lo->lo_encrypt_key_size) { | |
440 | ret = -EOPNOTSUPP; | |
441 | goto out; | |
442 | } | |
443 | ret = file->f_op->fallocate(file, mode, pos, | |
444 | bio->bi_size); | |
445 | if (unlikely(ret && ret != -EINVAL && | |
446 | ret != -EOPNOTSUPP)) | |
447 | ret = -EIO; | |
448 | goto out; | |
449 | } | |
450 | ||
511de73f | 451 | ret = lo_send(lo, bio, pos); |
68db1961 | 452 | |
6259f284 | 453 | if ((bio->bi_rw & REQ_FUA) && !ret) { |
8018ab05 | 454 | ret = vfs_fsync(file, 0); |
6259f284 | 455 | if (unlikely(ret && ret != -EINVAL)) |
68db1961 NK |
456 | ret = -EIO; |
457 | } | |
458 | } else | |
1da177e4 | 459 | ret = lo_receive(lo, bio, lo->lo_blocksize, pos); |
68db1961 NK |
460 | |
461 | out: | |
1da177e4 LT |
462 | return ret; |
463 | } | |
464 | ||
465 | /* | |
466 | * Add bio to back of pending list | |
467 | */ | |
468 | static void loop_add_bio(struct loop_device *lo, struct bio *bio) | |
469 | { | |
7b5a3522 | 470 | lo->lo_bio_count++; |
e686307f | 471 | bio_list_add(&lo->lo_bio_list, bio); |
1da177e4 LT |
472 | } |
473 | ||
474 | /* | |
475 | * Grab first pending buffer | |
476 | */ | |
477 | static struct bio *loop_get_bio(struct loop_device *lo) | |
478 | { | |
7b5a3522 | 479 | lo->lo_bio_count--; |
e686307f | 480 | return bio_list_pop(&lo->lo_bio_list); |
1da177e4 LT |
481 | } |
482 | ||
5a7bbad2 | 483 | static void loop_make_request(struct request_queue *q, struct bio *old_bio) |
1da177e4 LT |
484 | { |
485 | struct loop_device *lo = q->queuedata; | |
486 | int rw = bio_rw(old_bio); | |
487 | ||
35a82d1a NP |
488 | if (rw == READA) |
489 | rw = READ; | |
490 | ||
491 | BUG_ON(!lo || (rw != READ && rw != WRITE)); | |
1da177e4 LT |
492 | |
493 | spin_lock_irq(&lo->lo_lock); | |
494 | if (lo->lo_state != Lo_bound) | |
35a82d1a NP |
495 | goto out; |
496 | if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY))) | |
497 | goto out; | |
7b5a3522 LC |
498 | if (lo->lo_bio_count >= q->nr_congestion_on) |
499 | wait_event_lock_irq(lo->lo_req_wait, | |
500 | lo->lo_bio_count < q->nr_congestion_off, | |
501 | lo->lo_lock); | |
1da177e4 | 502 | loop_add_bio(lo, old_bio); |
6c997918 | 503 | wake_up(&lo->lo_event); |
35a82d1a | 504 | spin_unlock_irq(&lo->lo_lock); |
5a7bbad2 | 505 | return; |
35a82d1a | 506 | |
1da177e4 | 507 | out: |
35a82d1a | 508 | spin_unlock_irq(&lo->lo_lock); |
6712ecf8 | 509 | bio_io_error(old_bio); |
1da177e4 LT |
510 | } |
511 | ||
1da177e4 LT |
512 | struct switch_request { |
513 | struct file *file; | |
514 | struct completion wait; | |
515 | }; | |
516 | ||
517 | static void do_loop_switch(struct loop_device *, struct switch_request *); | |
518 | ||
519 | static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) | |
520 | { | |
1da177e4 LT |
521 | if (unlikely(!bio->bi_bdev)) { |
522 | do_loop_switch(lo, bio->bi_private); | |
523 | bio_put(bio); | |
524 | } else { | |
35a82d1a | 525 | int ret = do_bio_filebacked(lo, bio); |
6712ecf8 | 526 | bio_endio(bio, ret); |
1da177e4 LT |
527 | } |
528 | } | |
529 | ||
530 | /* | |
531 | * worker thread that handles reads/writes to file backed loop devices, | |
532 | * to avoid blocking in our make_request_fn. it also does loop decrypting | |
533 | * on reads for block backed loop, as that is too heavy to do from | |
534 | * b_end_io context where irqs may be disabled. | |
6c997918 SH |
535 | * |
536 | * Loop explanation: loop_clr_fd() sets lo_state to Lo_rundown before | |
537 | * calling kthread_stop(). Therefore once kthread_should_stop() is | |
538 | * true, make_request will not place any more requests. Therefore | |
539 | * once kthread_should_stop() is true and lo_bio is NULL, we are | |
540 | * done with the loop. | |
1da177e4 LT |
541 | */ |
542 | static int loop_thread(void *data) | |
543 | { | |
544 | struct loop_device *lo = data; | |
545 | struct bio *bio; | |
546 | ||
1da177e4 LT |
547 | set_user_nice(current, -20); |
548 | ||
e686307f | 549 | while (!kthread_should_stop() || !bio_list_empty(&lo->lo_bio_list)) { |
09c0dc68 | 550 | |
6c997918 | 551 | wait_event_interruptible(lo->lo_event, |
e686307f AM |
552 | !bio_list_empty(&lo->lo_bio_list) || |
553 | kthread_should_stop()); | |
35a82d1a | 554 | |
e686307f | 555 | if (bio_list_empty(&lo->lo_bio_list)) |
35a82d1a | 556 | continue; |
35a82d1a | 557 | spin_lock_irq(&lo->lo_lock); |
1da177e4 | 558 | bio = loop_get_bio(lo); |
7b5a3522 LC |
559 | if (lo->lo_bio_count < lo->lo_queue->nr_congestion_off) |
560 | wake_up(&lo->lo_req_wait); | |
35a82d1a NP |
561 | spin_unlock_irq(&lo->lo_lock); |
562 | ||
563 | BUG_ON(!bio); | |
1da177e4 | 564 | loop_handle_bio(lo, bio); |
1da177e4 LT |
565 | } |
566 | ||
1da177e4 LT |
567 | return 0; |
568 | } | |
569 | ||
570 | /* | |
571 | * loop_switch performs the hard work of switching a backing store. | |
572 | * First it needs to flush existing IO, it does this by sending a magic | |
573 | * BIO down the pipe. The completion of this BIO does the actual switch. | |
574 | */ | |
575 | static int loop_switch(struct loop_device *lo, struct file *file) | |
576 | { | |
577 | struct switch_request w; | |
a24eab1e | 578 | struct bio *bio = bio_alloc(GFP_KERNEL, 0); |
1da177e4 LT |
579 | if (!bio) |
580 | return -ENOMEM; | |
581 | init_completion(&w.wait); | |
582 | w.file = file; | |
583 | bio->bi_private = &w; | |
584 | bio->bi_bdev = NULL; | |
585 | loop_make_request(lo->lo_queue, bio); | |
586 | wait_for_completion(&w.wait); | |
587 | return 0; | |
588 | } | |
589 | ||
14f27939 MB |
590 | /* |
591 | * Helper to flush the IOs in loop, but keeping loop thread running | |
592 | */ | |
593 | static int loop_flush(struct loop_device *lo) | |
594 | { | |
595 | /* loop not yet configured, no running thread, nothing to flush */ | |
596 | if (!lo->lo_thread) | |
597 | return 0; | |
598 | ||
599 | return loop_switch(lo, NULL); | |
600 | } | |
601 | ||
1da177e4 LT |
602 | /* |
603 | * Do the actual switch; called from the BIO completion routine | |
604 | */ | |
605 | static void do_loop_switch(struct loop_device *lo, struct switch_request *p) | |
606 | { | |
607 | struct file *file = p->file; | |
608 | struct file *old_file = lo->lo_backing_file; | |
14f27939 MB |
609 | struct address_space *mapping; |
610 | ||
611 | /* if no new file, only flush of queued bios requested */ | |
612 | if (!file) | |
613 | goto out; | |
1da177e4 | 614 | |
14f27939 | 615 | mapping = file->f_mapping; |
1da177e4 LT |
616 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); |
617 | lo->lo_backing_file = file; | |
ba52de12 TT |
618 | lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ? |
619 | mapping->host->i_bdev->bd_block_size : PAGE_SIZE; | |
1da177e4 LT |
620 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
621 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
14f27939 | 622 | out: |
1da177e4 LT |
623 | complete(&p->wait); |
624 | } | |
625 | ||
626 | ||
627 | /* | |
628 | * loop_change_fd switched the backing store of a loopback device to | |
629 | * a new file. This is useful for operating system installers to free up | |
630 | * the original file and in High Availability environments to switch to | |
631 | * an alternative location for the content in case of server meltdown. | |
632 | * This can only work if the loop device is used read-only, and if the | |
633 | * new backing store is the same size and type as the old backing store. | |
634 | */ | |
bb214884 AV |
635 | static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
636 | unsigned int arg) | |
1da177e4 LT |
637 | { |
638 | struct file *file, *old_file; | |
639 | struct inode *inode; | |
640 | int error; | |
641 | ||
642 | error = -ENXIO; | |
643 | if (lo->lo_state != Lo_bound) | |
644 | goto out; | |
645 | ||
646 | /* the loop device has to be read-only */ | |
647 | error = -EINVAL; | |
648 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) | |
649 | goto out; | |
650 | ||
651 | error = -EBADF; | |
652 | file = fget(arg); | |
653 | if (!file) | |
654 | goto out; | |
655 | ||
656 | inode = file->f_mapping->host; | |
657 | old_file = lo->lo_backing_file; | |
658 | ||
659 | error = -EINVAL; | |
660 | ||
661 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
662 | goto out_putf; | |
663 | ||
1da177e4 LT |
664 | /* size of the new backing store needs to be the same */ |
665 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) | |
666 | goto out_putf; | |
667 | ||
668 | /* and ... switch */ | |
669 | error = loop_switch(lo, file); | |
670 | if (error) | |
671 | goto out_putf; | |
672 | ||
673 | fput(old_file); | |
e03c8dd1 | 674 | if (lo->lo_flags & LO_FLAGS_PARTSCAN) |
476a4813 | 675 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
1da177e4 LT |
676 | return 0; |
677 | ||
678 | out_putf: | |
679 | fput(file); | |
680 | out: | |
681 | return error; | |
682 | } | |
683 | ||
684 | static inline int is_loop_device(struct file *file) | |
685 | { | |
686 | struct inode *i = file->f_mapping->host; | |
687 | ||
688 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; | |
689 | } | |
690 | ||
ee862730 MB |
691 | /* loop sysfs attributes */ |
692 | ||
693 | static ssize_t loop_attr_show(struct device *dev, char *page, | |
694 | ssize_t (*callback)(struct loop_device *, char *)) | |
695 | { | |
34dd82af KS |
696 | struct gendisk *disk = dev_to_disk(dev); |
697 | struct loop_device *lo = disk->private_data; | |
ee862730 | 698 | |
34dd82af | 699 | return callback(lo, page); |
ee862730 MB |
700 | } |
701 | ||
702 | #define LOOP_ATTR_RO(_name) \ | |
703 | static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ | |
704 | static ssize_t loop_attr_do_show_##_name(struct device *d, \ | |
705 | struct device_attribute *attr, char *b) \ | |
706 | { \ | |
707 | return loop_attr_show(d, b, loop_attr_##_name##_show); \ | |
708 | } \ | |
709 | static struct device_attribute loop_attr_##_name = \ | |
710 | __ATTR(_name, S_IRUGO, loop_attr_do_show_##_name, NULL); | |
711 | ||
712 | static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) | |
713 | { | |
714 | ssize_t ret; | |
715 | char *p = NULL; | |
716 | ||
05eb0f25 | 717 | spin_lock_irq(&lo->lo_lock); |
ee862730 MB |
718 | if (lo->lo_backing_file) |
719 | p = d_path(&lo->lo_backing_file->f_path, buf, PAGE_SIZE - 1); | |
05eb0f25 | 720 | spin_unlock_irq(&lo->lo_lock); |
ee862730 MB |
721 | |
722 | if (IS_ERR_OR_NULL(p)) | |
723 | ret = PTR_ERR(p); | |
724 | else { | |
725 | ret = strlen(p); | |
726 | memmove(buf, p, ret); | |
727 | buf[ret++] = '\n'; | |
728 | buf[ret] = 0; | |
729 | } | |
730 | ||
731 | return ret; | |
732 | } | |
733 | ||
734 | static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) | |
735 | { | |
736 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); | |
737 | } | |
738 | ||
739 | static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) | |
740 | { | |
741 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); | |
742 | } | |
743 | ||
744 | static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) | |
745 | { | |
746 | int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); | |
747 | ||
748 | return sprintf(buf, "%s\n", autoclear ? "1" : "0"); | |
749 | } | |
750 | ||
e03c8dd1 KS |
751 | static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf) |
752 | { | |
753 | int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN); | |
754 | ||
755 | return sprintf(buf, "%s\n", partscan ? "1" : "0"); | |
756 | } | |
757 | ||
ee862730 MB |
758 | LOOP_ATTR_RO(backing_file); |
759 | LOOP_ATTR_RO(offset); | |
760 | LOOP_ATTR_RO(sizelimit); | |
761 | LOOP_ATTR_RO(autoclear); | |
e03c8dd1 | 762 | LOOP_ATTR_RO(partscan); |
ee862730 MB |
763 | |
764 | static struct attribute *loop_attrs[] = { | |
765 | &loop_attr_backing_file.attr, | |
766 | &loop_attr_offset.attr, | |
767 | &loop_attr_sizelimit.attr, | |
768 | &loop_attr_autoclear.attr, | |
e03c8dd1 | 769 | &loop_attr_partscan.attr, |
ee862730 MB |
770 | NULL, |
771 | }; | |
772 | ||
773 | static struct attribute_group loop_attribute_group = { | |
774 | .name = "loop", | |
775 | .attrs= loop_attrs, | |
776 | }; | |
777 | ||
778 | static int loop_sysfs_init(struct loop_device *lo) | |
779 | { | |
780 | return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, | |
781 | &loop_attribute_group); | |
782 | } | |
783 | ||
784 | static void loop_sysfs_exit(struct loop_device *lo) | |
785 | { | |
786 | sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, | |
787 | &loop_attribute_group); | |
788 | } | |
789 | ||
dfaa2ef6 LC |
790 | static void loop_config_discard(struct loop_device *lo) |
791 | { | |
792 | struct file *file = lo->lo_backing_file; | |
793 | struct inode *inode = file->f_mapping->host; | |
794 | struct request_queue *q = lo->lo_queue; | |
795 | ||
796 | /* | |
797 | * We use punch hole to reclaim the free space used by the | |
798 | * image a.k.a. discard. However we do support discard if | |
799 | * encryption is enabled, because it may give an attacker | |
800 | * useful information. | |
801 | */ | |
802 | if ((!file->f_op->fallocate) || | |
803 | lo->lo_encrypt_key_size) { | |
804 | q->limits.discard_granularity = 0; | |
805 | q->limits.discard_alignment = 0; | |
806 | q->limits.max_discard_sectors = 0; | |
807 | q->limits.discard_zeroes_data = 0; | |
808 | queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q); | |
809 | return; | |
810 | } | |
811 | ||
812 | q->limits.discard_granularity = inode->i_sb->s_blocksize; | |
dfaf3c03 | 813 | q->limits.discard_alignment = 0; |
dfaa2ef6 LC |
814 | q->limits.max_discard_sectors = UINT_MAX >> 9; |
815 | q->limits.discard_zeroes_data = 1; | |
816 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); | |
817 | } | |
818 | ||
bb214884 | 819 | static int loop_set_fd(struct loop_device *lo, fmode_t mode, |
1da177e4 LT |
820 | struct block_device *bdev, unsigned int arg) |
821 | { | |
822 | struct file *file, *f; | |
823 | struct inode *inode; | |
824 | struct address_space *mapping; | |
825 | unsigned lo_blocksize; | |
826 | int lo_flags = 0; | |
827 | int error; | |
828 | loff_t size; | |
829 | ||
830 | /* This is safe, since we have a reference from open(). */ | |
831 | __module_get(THIS_MODULE); | |
832 | ||
833 | error = -EBADF; | |
834 | file = fget(arg); | |
835 | if (!file) | |
836 | goto out; | |
837 | ||
838 | error = -EBUSY; | |
839 | if (lo->lo_state != Lo_unbound) | |
840 | goto out_putf; | |
841 | ||
842 | /* Avoid recursion */ | |
843 | f = file; | |
844 | while (is_loop_device(f)) { | |
845 | struct loop_device *l; | |
846 | ||
bb214884 | 847 | if (f->f_mapping->host->i_bdev == bdev) |
1da177e4 LT |
848 | goto out_putf; |
849 | ||
850 | l = f->f_mapping->host->i_bdev->bd_disk->private_data; | |
851 | if (l->lo_state == Lo_unbound) { | |
852 | error = -EINVAL; | |
853 | goto out_putf; | |
854 | } | |
855 | f = l->lo_backing_file; | |
856 | } | |
857 | ||
858 | mapping = file->f_mapping; | |
859 | inode = mapping->host; | |
860 | ||
1da177e4 | 861 | error = -EINVAL; |
456be148 CH |
862 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
863 | goto out_putf; | |
1da177e4 | 864 | |
456be148 CH |
865 | if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || |
866 | !file->f_op->write) | |
867 | lo_flags |= LO_FLAGS_READ_ONLY; | |
ba52de12 | 868 | |
456be148 CH |
869 | lo_blocksize = S_ISBLK(inode->i_mode) ? |
870 | inode->i_bdev->bd_block_size : PAGE_SIZE; | |
1da177e4 | 871 | |
456be148 | 872 | error = -EFBIG; |
1da177e4 | 873 | size = get_loop_size(lo, file); |
456be148 | 874 | if ((loff_t)(sector_t)size != size) |
1da177e4 | 875 | goto out_putf; |
1da177e4 | 876 | |
456be148 | 877 | error = 0; |
1da177e4 LT |
878 | |
879 | set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); | |
880 | ||
881 | lo->lo_blocksize = lo_blocksize; | |
882 | lo->lo_device = bdev; | |
883 | lo->lo_flags = lo_flags; | |
884 | lo->lo_backing_file = file; | |
eefe85ee | 885 | lo->transfer = transfer_none; |
1da177e4 LT |
886 | lo->ioctl = NULL; |
887 | lo->lo_sizelimit = 0; | |
7b5a3522 | 888 | lo->lo_bio_count = 0; |
1da177e4 LT |
889 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
890 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
891 | ||
e686307f | 892 | bio_list_init(&lo->lo_bio_list); |
1da177e4 LT |
893 | |
894 | /* | |
895 | * set queue make_request_fn, and add limits based on lower level | |
896 | * device | |
897 | */ | |
898 | blk_queue_make_request(lo->lo_queue, loop_make_request); | |
899 | lo->lo_queue->queuedata = lo; | |
1da177e4 | 900 | |
68db1961 | 901 | if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
4913efe4 | 902 | blk_queue_flush(lo->lo_queue, REQ_FLUSH); |
68db1961 | 903 | |
73285082 | 904 | set_capacity(lo->lo_disk, size); |
1da177e4 | 905 | bd_set_size(bdev, size << 9); |
ee862730 | 906 | loop_sysfs_init(lo); |
c3473c63 DZ |
907 | /* let user-space know about the new size */ |
908 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1da177e4 LT |
909 | |
910 | set_blocksize(bdev, lo_blocksize); | |
911 | ||
6c997918 SH |
912 | lo->lo_thread = kthread_create(loop_thread, lo, "loop%d", |
913 | lo->lo_number); | |
914 | if (IS_ERR(lo->lo_thread)) { | |
915 | error = PTR_ERR(lo->lo_thread); | |
a7422bf8 | 916 | goto out_clr; |
6c997918 SH |
917 | } |
918 | lo->lo_state = Lo_bound; | |
919 | wake_up_process(lo->lo_thread); | |
e03c8dd1 KS |
920 | if (part_shift) |
921 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
922 | if (lo->lo_flags & LO_FLAGS_PARTSCAN) | |
476a4813 | 923 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
1da177e4 LT |
924 | return 0; |
925 | ||
a7422bf8 | 926 | out_clr: |
ee862730 | 927 | loop_sysfs_exit(lo); |
a7422bf8 SH |
928 | lo->lo_thread = NULL; |
929 | lo->lo_device = NULL; | |
930 | lo->lo_backing_file = NULL; | |
931 | lo->lo_flags = 0; | |
73285082 | 932 | set_capacity(lo->lo_disk, 0); |
f98393a6 | 933 | invalidate_bdev(bdev); |
a7422bf8 | 934 | bd_set_size(bdev, 0); |
c3473c63 | 935 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); |
a7422bf8 SH |
936 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask); |
937 | lo->lo_state = Lo_unbound; | |
1da177e4 LT |
938 | out_putf: |
939 | fput(file); | |
940 | out: | |
941 | /* This is safe: open() is still holding a reference. */ | |
942 | module_put(THIS_MODULE); | |
943 | return error; | |
944 | } | |
945 | ||
946 | static int | |
947 | loop_release_xfer(struct loop_device *lo) | |
948 | { | |
949 | int err = 0; | |
950 | struct loop_func_table *xfer = lo->lo_encryption; | |
951 | ||
952 | if (xfer) { | |
953 | if (xfer->release) | |
954 | err = xfer->release(lo); | |
955 | lo->transfer = NULL; | |
956 | lo->lo_encryption = NULL; | |
957 | module_put(xfer->owner); | |
958 | } | |
959 | return err; | |
960 | } | |
961 | ||
962 | static int | |
963 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, | |
964 | const struct loop_info64 *i) | |
965 | { | |
966 | int err = 0; | |
967 | ||
968 | if (xfer) { | |
969 | struct module *owner = xfer->owner; | |
970 | ||
971 | if (!try_module_get(owner)) | |
972 | return -EINVAL; | |
973 | if (xfer->init) | |
974 | err = xfer->init(lo, i); | |
975 | if (err) | |
976 | module_put(owner); | |
977 | else | |
978 | lo->lo_encryption = xfer; | |
979 | } | |
980 | return err; | |
981 | } | |
982 | ||
4c823cc3 | 983 | static int loop_clr_fd(struct loop_device *lo) |
1da177e4 LT |
984 | { |
985 | struct file *filp = lo->lo_backing_file; | |
b4e3ca1a | 986 | gfp_t gfp = lo->old_gfp_mask; |
4c823cc3 | 987 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
988 | |
989 | if (lo->lo_state != Lo_bound) | |
990 | return -ENXIO; | |
991 | ||
a1ecac3b DC |
992 | /* |
993 | * If we've explicitly asked to tear down the loop device, | |
994 | * and it has an elevated reference count, set it for auto-teardown when | |
995 | * the last reference goes away. This stops $!~#$@ udev from | |
996 | * preventing teardown because it decided that it needs to run blkid on | |
997 | * the loopback device whenever they appear. xfstests is notorious for | |
998 | * failing tests because blkid via udev races with a losetup | |
999 | * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d | |
1000 | * command to fail with EBUSY. | |
1001 | */ | |
1002 | if (lo->lo_refcnt > 1) { | |
1003 | lo->lo_flags |= LO_FLAGS_AUTOCLEAR; | |
1004 | mutex_unlock(&lo->lo_ctl_mutex); | |
1005 | return 0; | |
1006 | } | |
1da177e4 LT |
1007 | |
1008 | if (filp == NULL) | |
1009 | return -EINVAL; | |
1010 | ||
1011 | spin_lock_irq(&lo->lo_lock); | |
1012 | lo->lo_state = Lo_rundown; | |
1da177e4 LT |
1013 | spin_unlock_irq(&lo->lo_lock); |
1014 | ||
6c997918 | 1015 | kthread_stop(lo->lo_thread); |
1da177e4 | 1016 | |
05eb0f25 | 1017 | spin_lock_irq(&lo->lo_lock); |
1da177e4 | 1018 | lo->lo_backing_file = NULL; |
05eb0f25 | 1019 | spin_unlock_irq(&lo->lo_lock); |
1da177e4 LT |
1020 | |
1021 | loop_release_xfer(lo); | |
1022 | lo->transfer = NULL; | |
1023 | lo->ioctl = NULL; | |
1024 | lo->lo_device = NULL; | |
1025 | lo->lo_encryption = NULL; | |
1026 | lo->lo_offset = 0; | |
1027 | lo->lo_sizelimit = 0; | |
1028 | lo->lo_encrypt_key_size = 0; | |
6c997918 | 1029 | lo->lo_thread = NULL; |
1da177e4 LT |
1030 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
1031 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); | |
1032 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); | |
bb214884 AV |
1033 | if (bdev) |
1034 | invalidate_bdev(bdev); | |
73285082 | 1035 | set_capacity(lo->lo_disk, 0); |
51a0bb0c | 1036 | loop_sysfs_exit(lo); |
c3473c63 | 1037 | if (bdev) { |
bb214884 | 1038 | bd_set_size(bdev, 0); |
c3473c63 DZ |
1039 | /* let user-space know about this change */ |
1040 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1041 | } | |
1da177e4 LT |
1042 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
1043 | lo->lo_state = Lo_unbound; | |
1da177e4 LT |
1044 | /* This is safe: open() is still holding a reference. */ |
1045 | module_put(THIS_MODULE); | |
e03c8dd1 | 1046 | if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) |
476a4813 | 1047 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
e03c8dd1 KS |
1048 | lo->lo_flags = 0; |
1049 | if (!part_shift) | |
1050 | lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; | |
f028f3b2 NK |
1051 | mutex_unlock(&lo->lo_ctl_mutex); |
1052 | /* | |
1053 | * Need not hold lo_ctl_mutex to fput backing file. | |
1054 | * Calling fput holding lo_ctl_mutex triggers a circular | |
1055 | * lock dependency possibility warning as fput can take | |
1056 | * bd_mutex which is usually taken before lo_ctl_mutex. | |
1057 | */ | |
1058 | fput(filp); | |
1da177e4 LT |
1059 | return 0; |
1060 | } | |
1061 | ||
1062 | static int | |
1063 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) | |
1064 | { | |
1065 | int err; | |
1066 | struct loop_func_table *xfer; | |
e4849737 | 1067 | kuid_t uid = current_uid(); |
1da177e4 | 1068 | |
b0fafa81 | 1069 | if (lo->lo_encrypt_key_size && |
e4849737 | 1070 | !uid_eq(lo->lo_key_owner, uid) && |
1da177e4 LT |
1071 | !capable(CAP_SYS_ADMIN)) |
1072 | return -EPERM; | |
1073 | if (lo->lo_state != Lo_bound) | |
1074 | return -ENXIO; | |
1075 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) | |
1076 | return -EINVAL; | |
1077 | ||
1078 | err = loop_release_xfer(lo); | |
1079 | if (err) | |
1080 | return err; | |
1081 | ||
1082 | if (info->lo_encrypt_type) { | |
1083 | unsigned int type = info->lo_encrypt_type; | |
1084 | ||
1085 | if (type >= MAX_LO_CRYPT) | |
1086 | return -EINVAL; | |
1087 | xfer = xfer_funcs[type]; | |
1088 | if (xfer == NULL) | |
1089 | return -EINVAL; | |
1090 | } else | |
1091 | xfer = NULL; | |
1092 | ||
1093 | err = loop_init_xfer(lo, xfer, info); | |
1094 | if (err) | |
1095 | return err; | |
1096 | ||
1097 | if (lo->lo_offset != info->lo_offset || | |
7b0576a3 | 1098 | lo->lo_sizelimit != info->lo_sizelimit) |
7035b5df | 1099 | if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) |
1da177e4 | 1100 | return -EFBIG; |
541c742a | 1101 | |
dfaa2ef6 | 1102 | loop_config_discard(lo); |
1da177e4 LT |
1103 | |
1104 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); | |
1105 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); | |
1106 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; | |
1107 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; | |
1108 | ||
1109 | if (!xfer) | |
1110 | xfer = &none_funcs; | |
1111 | lo->transfer = xfer->transfer; | |
1112 | lo->ioctl = xfer->ioctl; | |
1113 | ||
96c58655 DW |
1114 | if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != |
1115 | (info->lo_flags & LO_FLAGS_AUTOCLEAR)) | |
1116 | lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; | |
1117 | ||
e03c8dd1 KS |
1118 | if ((info->lo_flags & LO_FLAGS_PARTSCAN) && |
1119 | !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { | |
1120 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
1121 | lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; | |
1122 | ioctl_by_bdev(lo->lo_device, BLKRRPART, 0); | |
1123 | } | |
1124 | ||
1da177e4 LT |
1125 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; |
1126 | lo->lo_init[0] = info->lo_init[0]; | |
1127 | lo->lo_init[1] = info->lo_init[1]; | |
1128 | if (info->lo_encrypt_key_size) { | |
1129 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, | |
1130 | info->lo_encrypt_key_size); | |
b0fafa81 | 1131 | lo->lo_key_owner = uid; |
1da177e4 LT |
1132 | } |
1133 | ||
1134 | return 0; | |
1135 | } | |
1136 | ||
1137 | static int | |
1138 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) | |
1139 | { | |
1140 | struct file *file = lo->lo_backing_file; | |
1141 | struct kstat stat; | |
1142 | int error; | |
1143 | ||
1144 | if (lo->lo_state != Lo_bound) | |
1145 | return -ENXIO; | |
6c648be6 | 1146 | error = vfs_getattr(file->f_path.mnt, file->f_path.dentry, &stat); |
1da177e4 LT |
1147 | if (error) |
1148 | return error; | |
1149 | memset(info, 0, sizeof(*info)); | |
1150 | info->lo_number = lo->lo_number; | |
1151 | info->lo_device = huge_encode_dev(stat.dev); | |
1152 | info->lo_inode = stat.ino; | |
1153 | info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev); | |
1154 | info->lo_offset = lo->lo_offset; | |
1155 | info->lo_sizelimit = lo->lo_sizelimit; | |
1156 | info->lo_flags = lo->lo_flags; | |
1157 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); | |
1158 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); | |
1159 | info->lo_encrypt_type = | |
1160 | lo->lo_encryption ? lo->lo_encryption->number : 0; | |
1161 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { | |
1162 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; | |
1163 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, | |
1164 | lo->lo_encrypt_key_size); | |
1165 | } | |
1166 | return 0; | |
1167 | } | |
1168 | ||
1169 | static void | |
1170 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) | |
1171 | { | |
1172 | memset(info64, 0, sizeof(*info64)); | |
1173 | info64->lo_number = info->lo_number; | |
1174 | info64->lo_device = info->lo_device; | |
1175 | info64->lo_inode = info->lo_inode; | |
1176 | info64->lo_rdevice = info->lo_rdevice; | |
1177 | info64->lo_offset = info->lo_offset; | |
1178 | info64->lo_sizelimit = 0; | |
1179 | info64->lo_encrypt_type = info->lo_encrypt_type; | |
1180 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; | |
1181 | info64->lo_flags = info->lo_flags; | |
1182 | info64->lo_init[0] = info->lo_init[0]; | |
1183 | info64->lo_init[1] = info->lo_init[1]; | |
1184 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1185 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); | |
1186 | else | |
1187 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); | |
1188 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); | |
1189 | } | |
1190 | ||
1191 | static int | |
1192 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) | |
1193 | { | |
1194 | memset(info, 0, sizeof(*info)); | |
1195 | info->lo_number = info64->lo_number; | |
1196 | info->lo_device = info64->lo_device; | |
1197 | info->lo_inode = info64->lo_inode; | |
1198 | info->lo_rdevice = info64->lo_rdevice; | |
1199 | info->lo_offset = info64->lo_offset; | |
1200 | info->lo_encrypt_type = info64->lo_encrypt_type; | |
1201 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1202 | info->lo_flags = info64->lo_flags; | |
1203 | info->lo_init[0] = info64->lo_init[0]; | |
1204 | info->lo_init[1] = info64->lo_init[1]; | |
1205 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1206 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1207 | else | |
1208 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1209 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1210 | ||
1211 | /* error in case values were truncated */ | |
1212 | if (info->lo_device != info64->lo_device || | |
1213 | info->lo_rdevice != info64->lo_rdevice || | |
1214 | info->lo_inode != info64->lo_inode || | |
1215 | info->lo_offset != info64->lo_offset) | |
1216 | return -EOVERFLOW; | |
1217 | ||
1218 | return 0; | |
1219 | } | |
1220 | ||
1221 | static int | |
1222 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) | |
1223 | { | |
1224 | struct loop_info info; | |
1225 | struct loop_info64 info64; | |
1226 | ||
1227 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) | |
1228 | return -EFAULT; | |
1229 | loop_info64_from_old(&info, &info64); | |
1230 | return loop_set_status(lo, &info64); | |
1231 | } | |
1232 | ||
1233 | static int | |
1234 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) | |
1235 | { | |
1236 | struct loop_info64 info64; | |
1237 | ||
1238 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) | |
1239 | return -EFAULT; | |
1240 | return loop_set_status(lo, &info64); | |
1241 | } | |
1242 | ||
1243 | static int | |
1244 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { | |
1245 | struct loop_info info; | |
1246 | struct loop_info64 info64; | |
1247 | int err = 0; | |
1248 | ||
1249 | if (!arg) | |
1250 | err = -EINVAL; | |
1251 | if (!err) | |
1252 | err = loop_get_status(lo, &info64); | |
1253 | if (!err) | |
1254 | err = loop_info64_to_old(&info64, &info); | |
1255 | if (!err && copy_to_user(arg, &info, sizeof(info))) | |
1256 | err = -EFAULT; | |
1257 | ||
1258 | return err; | |
1259 | } | |
1260 | ||
1261 | static int | |
1262 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { | |
1263 | struct loop_info64 info64; | |
1264 | int err = 0; | |
1265 | ||
1266 | if (!arg) | |
1267 | err = -EINVAL; | |
1268 | if (!err) | |
1269 | err = loop_get_status(lo, &info64); | |
1270 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) | |
1271 | err = -EFAULT; | |
1272 | ||
1273 | return err; | |
1274 | } | |
1275 | ||
53d66608 O |
1276 | static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) |
1277 | { | |
53d66608 | 1278 | if (unlikely(lo->lo_state != Lo_bound)) |
7b0576a3 | 1279 | return -ENXIO; |
53d66608 | 1280 | |
7b0576a3 | 1281 | return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); |
53d66608 O |
1282 | } |
1283 | ||
bb214884 | 1284 | static int lo_ioctl(struct block_device *bdev, fmode_t mode, |
1da177e4 LT |
1285 | unsigned int cmd, unsigned long arg) |
1286 | { | |
bb214884 | 1287 | struct loop_device *lo = bdev->bd_disk->private_data; |
1da177e4 LT |
1288 | int err; |
1289 | ||
f028f3b2 | 1290 | mutex_lock_nested(&lo->lo_ctl_mutex, 1); |
1da177e4 LT |
1291 | switch (cmd) { |
1292 | case LOOP_SET_FD: | |
bb214884 | 1293 | err = loop_set_fd(lo, mode, bdev, arg); |
1da177e4 LT |
1294 | break; |
1295 | case LOOP_CHANGE_FD: | |
bb214884 | 1296 | err = loop_change_fd(lo, bdev, arg); |
1da177e4 LT |
1297 | break; |
1298 | case LOOP_CLR_FD: | |
f028f3b2 | 1299 | /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ |
4c823cc3 | 1300 | err = loop_clr_fd(lo); |
f028f3b2 NK |
1301 | if (!err) |
1302 | goto out_unlocked; | |
1da177e4 LT |
1303 | break; |
1304 | case LOOP_SET_STATUS: | |
7035b5df DM |
1305 | err = -EPERM; |
1306 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1307 | err = loop_set_status_old(lo, | |
1308 | (struct loop_info __user *)arg); | |
1da177e4 LT |
1309 | break; |
1310 | case LOOP_GET_STATUS: | |
1311 | err = loop_get_status_old(lo, (struct loop_info __user *) arg); | |
1312 | break; | |
1313 | case LOOP_SET_STATUS64: | |
7035b5df DM |
1314 | err = -EPERM; |
1315 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1316 | err = loop_set_status64(lo, | |
1317 | (struct loop_info64 __user *) arg); | |
1da177e4 LT |
1318 | break; |
1319 | case LOOP_GET_STATUS64: | |
1320 | err = loop_get_status64(lo, (struct loop_info64 __user *) arg); | |
1321 | break; | |
53d66608 O |
1322 | case LOOP_SET_CAPACITY: |
1323 | err = -EPERM; | |
1324 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1325 | err = loop_set_capacity(lo, bdev); | |
1326 | break; | |
1da177e4 LT |
1327 | default: |
1328 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; | |
1329 | } | |
f85221dd | 1330 | mutex_unlock(&lo->lo_ctl_mutex); |
f028f3b2 NK |
1331 | |
1332 | out_unlocked: | |
1da177e4 LT |
1333 | return err; |
1334 | } | |
1335 | ||
863d5b82 DH |
1336 | #ifdef CONFIG_COMPAT |
1337 | struct compat_loop_info { | |
1338 | compat_int_t lo_number; /* ioctl r/o */ | |
1339 | compat_dev_t lo_device; /* ioctl r/o */ | |
1340 | compat_ulong_t lo_inode; /* ioctl r/o */ | |
1341 | compat_dev_t lo_rdevice; /* ioctl r/o */ | |
1342 | compat_int_t lo_offset; | |
1343 | compat_int_t lo_encrypt_type; | |
1344 | compat_int_t lo_encrypt_key_size; /* ioctl w/o */ | |
1345 | compat_int_t lo_flags; /* ioctl r/o */ | |
1346 | char lo_name[LO_NAME_SIZE]; | |
1347 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ | |
1348 | compat_ulong_t lo_init[2]; | |
1349 | char reserved[4]; | |
1350 | }; | |
1351 | ||
1352 | /* | |
1353 | * Transfer 32-bit compatibility structure in userspace to 64-bit loop info | |
1354 | * - noinlined to reduce stack space usage in main part of driver | |
1355 | */ | |
1356 | static noinline int | |
ba674cfc | 1357 | loop_info64_from_compat(const struct compat_loop_info __user *arg, |
863d5b82 DH |
1358 | struct loop_info64 *info64) |
1359 | { | |
1360 | struct compat_loop_info info; | |
1361 | ||
1362 | if (copy_from_user(&info, arg, sizeof(info))) | |
1363 | return -EFAULT; | |
1364 | ||
1365 | memset(info64, 0, sizeof(*info64)); | |
1366 | info64->lo_number = info.lo_number; | |
1367 | info64->lo_device = info.lo_device; | |
1368 | info64->lo_inode = info.lo_inode; | |
1369 | info64->lo_rdevice = info.lo_rdevice; | |
1370 | info64->lo_offset = info.lo_offset; | |
1371 | info64->lo_sizelimit = 0; | |
1372 | info64->lo_encrypt_type = info.lo_encrypt_type; | |
1373 | info64->lo_encrypt_key_size = info.lo_encrypt_key_size; | |
1374 | info64->lo_flags = info.lo_flags; | |
1375 | info64->lo_init[0] = info.lo_init[0]; | |
1376 | info64->lo_init[1] = info.lo_init[1]; | |
1377 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1378 | memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); | |
1379 | else | |
1380 | memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); | |
1381 | memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); | |
1382 | return 0; | |
1383 | } | |
1384 | ||
1385 | /* | |
1386 | * Transfer 64-bit loop info to 32-bit compatibility structure in userspace | |
1387 | * - noinlined to reduce stack space usage in main part of driver | |
1388 | */ | |
1389 | static noinline int | |
1390 | loop_info64_to_compat(const struct loop_info64 *info64, | |
1391 | struct compat_loop_info __user *arg) | |
1392 | { | |
1393 | struct compat_loop_info info; | |
1394 | ||
1395 | memset(&info, 0, sizeof(info)); | |
1396 | info.lo_number = info64->lo_number; | |
1397 | info.lo_device = info64->lo_device; | |
1398 | info.lo_inode = info64->lo_inode; | |
1399 | info.lo_rdevice = info64->lo_rdevice; | |
1400 | info.lo_offset = info64->lo_offset; | |
1401 | info.lo_encrypt_type = info64->lo_encrypt_type; | |
1402 | info.lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1403 | info.lo_flags = info64->lo_flags; | |
1404 | info.lo_init[0] = info64->lo_init[0]; | |
1405 | info.lo_init[1] = info64->lo_init[1]; | |
1406 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1407 | memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1408 | else | |
1409 | memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1410 | memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1411 | ||
1412 | /* error in case values were truncated */ | |
1413 | if (info.lo_device != info64->lo_device || | |
1414 | info.lo_rdevice != info64->lo_rdevice || | |
1415 | info.lo_inode != info64->lo_inode || | |
1416 | info.lo_offset != info64->lo_offset || | |
1417 | info.lo_init[0] != info64->lo_init[0] || | |
1418 | info.lo_init[1] != info64->lo_init[1]) | |
1419 | return -EOVERFLOW; | |
1420 | ||
1421 | if (copy_to_user(arg, &info, sizeof(info))) | |
1422 | return -EFAULT; | |
1423 | return 0; | |
1424 | } | |
1425 | ||
1426 | static int | |
1427 | loop_set_status_compat(struct loop_device *lo, | |
1428 | const struct compat_loop_info __user *arg) | |
1429 | { | |
1430 | struct loop_info64 info64; | |
1431 | int ret; | |
1432 | ||
1433 | ret = loop_info64_from_compat(arg, &info64); | |
1434 | if (ret < 0) | |
1435 | return ret; | |
1436 | return loop_set_status(lo, &info64); | |
1437 | } | |
1438 | ||
1439 | static int | |
1440 | loop_get_status_compat(struct loop_device *lo, | |
1441 | struct compat_loop_info __user *arg) | |
1442 | { | |
1443 | struct loop_info64 info64; | |
1444 | int err = 0; | |
1445 | ||
1446 | if (!arg) | |
1447 | err = -EINVAL; | |
1448 | if (!err) | |
1449 | err = loop_get_status(lo, &info64); | |
1450 | if (!err) | |
1451 | err = loop_info64_to_compat(&info64, arg); | |
1452 | return err; | |
1453 | } | |
1454 | ||
bb214884 AV |
1455 | static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
1456 | unsigned int cmd, unsigned long arg) | |
863d5b82 | 1457 | { |
bb214884 | 1458 | struct loop_device *lo = bdev->bd_disk->private_data; |
863d5b82 DH |
1459 | int err; |
1460 | ||
863d5b82 DH |
1461 | switch(cmd) { |
1462 | case LOOP_SET_STATUS: | |
1463 | mutex_lock(&lo->lo_ctl_mutex); | |
1464 | err = loop_set_status_compat( | |
1465 | lo, (const struct compat_loop_info __user *) arg); | |
1466 | mutex_unlock(&lo->lo_ctl_mutex); | |
1467 | break; | |
1468 | case LOOP_GET_STATUS: | |
1469 | mutex_lock(&lo->lo_ctl_mutex); | |
1470 | err = loop_get_status_compat( | |
1471 | lo, (struct compat_loop_info __user *) arg); | |
1472 | mutex_unlock(&lo->lo_ctl_mutex); | |
1473 | break; | |
53d66608 | 1474 | case LOOP_SET_CAPACITY: |
863d5b82 DH |
1475 | case LOOP_CLR_FD: |
1476 | case LOOP_GET_STATUS64: | |
1477 | case LOOP_SET_STATUS64: | |
1478 | arg = (unsigned long) compat_ptr(arg); | |
1479 | case LOOP_SET_FD: | |
1480 | case LOOP_CHANGE_FD: | |
bb214884 | 1481 | err = lo_ioctl(bdev, mode, cmd, arg); |
863d5b82 DH |
1482 | break; |
1483 | default: | |
1484 | err = -ENOIOCTLCMD; | |
1485 | break; | |
1486 | } | |
863d5b82 DH |
1487 | return err; |
1488 | } | |
1489 | #endif | |
1490 | ||
bb214884 | 1491 | static int lo_open(struct block_device *bdev, fmode_t mode) |
1da177e4 | 1492 | { |
770fe30a KS |
1493 | struct loop_device *lo; |
1494 | int err = 0; | |
1495 | ||
1496 | mutex_lock(&loop_index_mutex); | |
1497 | lo = bdev->bd_disk->private_data; | |
1498 | if (!lo) { | |
1499 | err = -ENXIO; | |
1500 | goto out; | |
1501 | } | |
1da177e4 | 1502 | |
f85221dd | 1503 | mutex_lock(&lo->lo_ctl_mutex); |
1da177e4 | 1504 | lo->lo_refcnt++; |
f85221dd | 1505 | mutex_unlock(&lo->lo_ctl_mutex); |
770fe30a KS |
1506 | out: |
1507 | mutex_unlock(&loop_index_mutex); | |
1508 | return err; | |
1da177e4 LT |
1509 | } |
1510 | ||
bb214884 | 1511 | static int lo_release(struct gendisk *disk, fmode_t mode) |
1da177e4 | 1512 | { |
bb214884 | 1513 | struct loop_device *lo = disk->private_data; |
ffcd7dca | 1514 | int err; |
1da177e4 | 1515 | |
f85221dd | 1516 | mutex_lock(&lo->lo_ctl_mutex); |
96c58655 | 1517 | |
14f27939 MB |
1518 | if (--lo->lo_refcnt) |
1519 | goto out; | |
1520 | ||
1521 | if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { | |
1522 | /* | |
1523 | * In autoclear mode, stop the loop thread | |
1524 | * and remove configuration after last close. | |
1525 | */ | |
4c823cc3 | 1526 | err = loop_clr_fd(lo); |
ffcd7dca AB |
1527 | if (!err) |
1528 | goto out_unlocked; | |
14f27939 MB |
1529 | } else { |
1530 | /* | |
1531 | * Otherwise keep thread (if running) and config, | |
1532 | * but flush possible ongoing bios in thread. | |
1533 | */ | |
1534 | loop_flush(lo); | |
1535 | } | |
96c58655 | 1536 | |
14f27939 | 1537 | out: |
f85221dd | 1538 | mutex_unlock(&lo->lo_ctl_mutex); |
ffcd7dca | 1539 | out_unlocked: |
1da177e4 LT |
1540 | return 0; |
1541 | } | |
1542 | ||
83d5cde4 | 1543 | static const struct block_device_operations lo_fops = { |
1da177e4 | 1544 | .owner = THIS_MODULE, |
bb214884 AV |
1545 | .open = lo_open, |
1546 | .release = lo_release, | |
1547 | .ioctl = lo_ioctl, | |
863d5b82 | 1548 | #ifdef CONFIG_COMPAT |
bb214884 | 1549 | .compat_ioctl = lo_compat_ioctl, |
863d5b82 | 1550 | #endif |
1da177e4 LT |
1551 | }; |
1552 | ||
1553 | /* | |
1554 | * And now the modules code and kernel interface. | |
1555 | */ | |
73285082 | 1556 | static int max_loop; |
ac04fee0 | 1557 | module_param(max_loop, int, S_IRUGO); |
a47653fc | 1558 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
ac04fee0 | 1559 | module_param(max_part, int, S_IRUGO); |
476a4813 | 1560 | MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
1da177e4 LT |
1561 | MODULE_LICENSE("GPL"); |
1562 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); | |
1563 | ||
1564 | int loop_register_transfer(struct loop_func_table *funcs) | |
1565 | { | |
1566 | unsigned int n = funcs->number; | |
1567 | ||
1568 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) | |
1569 | return -EINVAL; | |
1570 | xfer_funcs[n] = funcs; | |
1571 | return 0; | |
1572 | } | |
1573 | ||
34dd82af KS |
1574 | static int unregister_transfer_cb(int id, void *ptr, void *data) |
1575 | { | |
1576 | struct loop_device *lo = ptr; | |
1577 | struct loop_func_table *xfer = data; | |
1578 | ||
1579 | mutex_lock(&lo->lo_ctl_mutex); | |
1580 | if (lo->lo_encryption == xfer) | |
1581 | loop_release_xfer(lo); | |
1582 | mutex_unlock(&lo->lo_ctl_mutex); | |
1583 | return 0; | |
1584 | } | |
1585 | ||
1da177e4 LT |
1586 | int loop_unregister_transfer(int number) |
1587 | { | |
1588 | unsigned int n = number; | |
1da177e4 LT |
1589 | struct loop_func_table *xfer; |
1590 | ||
1591 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) | |
1592 | return -EINVAL; | |
1593 | ||
1594 | xfer_funcs[n] = NULL; | |
34dd82af | 1595 | idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer); |
1da177e4 LT |
1596 | return 0; |
1597 | } | |
1598 | ||
1599 | EXPORT_SYMBOL(loop_register_transfer); | |
1600 | EXPORT_SYMBOL(loop_unregister_transfer); | |
1601 | ||
34dd82af | 1602 | static int loop_add(struct loop_device **l, int i) |
73285082 KC |
1603 | { |
1604 | struct loop_device *lo; | |
1605 | struct gendisk *disk; | |
34dd82af | 1606 | int err; |
73285082 | 1607 | |
68d740d7 | 1608 | err = -ENOMEM; |
73285082 | 1609 | lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
68d740d7 | 1610 | if (!lo) |
73285082 | 1611 | goto out; |
34dd82af | 1612 | |
68d740d7 | 1613 | if (!idr_pre_get(&loop_index_idr, GFP_KERNEL)) |
34dd82af KS |
1614 | goto out_free_dev; |
1615 | ||
1616 | if (i >= 0) { | |
1617 | int m; | |
1618 | ||
1619 | /* create specific i in the index */ | |
1620 | err = idr_get_new_above(&loop_index_idr, lo, i, &m); | |
1621 | if (err >= 0 && i != m) { | |
1622 | idr_remove(&loop_index_idr, m); | |
1623 | err = -EEXIST; | |
1624 | } | |
770fe30a KS |
1625 | } else if (i == -1) { |
1626 | int m; | |
1627 | ||
1628 | /* get next free nr */ | |
1629 | err = idr_get_new(&loop_index_idr, lo, &m); | |
1630 | if (err >= 0) | |
1631 | i = m; | |
34dd82af KS |
1632 | } else { |
1633 | err = -EINVAL; | |
1634 | } | |
1635 | if (err < 0) | |
1636 | goto out_free_dev; | |
73285082 KC |
1637 | |
1638 | lo->lo_queue = blk_alloc_queue(GFP_KERNEL); | |
1639 | if (!lo->lo_queue) | |
1640 | goto out_free_dev; | |
1641 | ||
476a4813 | 1642 | disk = lo->lo_disk = alloc_disk(1 << part_shift); |
73285082 KC |
1643 | if (!disk) |
1644 | goto out_free_queue; | |
1645 | ||
e03c8dd1 KS |
1646 | /* |
1647 | * Disable partition scanning by default. The in-kernel partition | |
1648 | * scanning can be requested individually per-device during its | |
1649 | * setup. Userspace can always add and remove partitions from all | |
1650 | * devices. The needed partition minors are allocated from the | |
1651 | * extended minor space, the main loop device numbers will continue | |
1652 | * to match the loop minors, regardless of the number of partitions | |
1653 | * used. | |
1654 | * | |
1655 | * If max_part is given, partition scanning is globally enabled for | |
1656 | * all loop devices. The minors for the main loop devices will be | |
1657 | * multiples of max_part. | |
1658 | * | |
1659 | * Note: Global-for-all-devices, set-only-at-init, read-only module | |
1660 | * parameteters like 'max_loop' and 'max_part' make things needlessly | |
1661 | * complicated, are too static, inflexible and may surprise | |
1662 | * userspace tools. Parameters like this in general should be avoided. | |
1663 | */ | |
1664 | if (!part_shift) | |
1665 | disk->flags |= GENHD_FL_NO_PART_SCAN; | |
1666 | disk->flags |= GENHD_FL_EXT_DEVT; | |
73285082 KC |
1667 | mutex_init(&lo->lo_ctl_mutex); |
1668 | lo->lo_number = i; | |
1669 | lo->lo_thread = NULL; | |
1670 | init_waitqueue_head(&lo->lo_event); | |
7b5a3522 | 1671 | init_waitqueue_head(&lo->lo_req_wait); |
73285082 KC |
1672 | spin_lock_init(&lo->lo_lock); |
1673 | disk->major = LOOP_MAJOR; | |
476a4813 | 1674 | disk->first_minor = i << part_shift; |
73285082 KC |
1675 | disk->fops = &lo_fops; |
1676 | disk->private_data = lo; | |
1677 | disk->queue = lo->lo_queue; | |
1678 | sprintf(disk->disk_name, "loop%d", i); | |
34dd82af KS |
1679 | add_disk(disk); |
1680 | *l = lo; | |
1681 | return lo->lo_number; | |
73285082 KC |
1682 | |
1683 | out_free_queue: | |
1684 | blk_cleanup_queue(lo->lo_queue); | |
1685 | out_free_dev: | |
1686 | kfree(lo); | |
1687 | out: | |
34dd82af | 1688 | return err; |
73285082 KC |
1689 | } |
1690 | ||
34dd82af | 1691 | static void loop_remove(struct loop_device *lo) |
1da177e4 | 1692 | { |
34dd82af | 1693 | del_gendisk(lo->lo_disk); |
73285082 KC |
1694 | blk_cleanup_queue(lo->lo_queue); |
1695 | put_disk(lo->lo_disk); | |
73285082 KC |
1696 | kfree(lo); |
1697 | } | |
1da177e4 | 1698 | |
770fe30a KS |
1699 | static int find_free_cb(int id, void *ptr, void *data) |
1700 | { | |
1701 | struct loop_device *lo = ptr; | |
1702 | struct loop_device **l = data; | |
1703 | ||
1704 | if (lo->lo_state == Lo_unbound) { | |
1705 | *l = lo; | |
1706 | return 1; | |
1707 | } | |
1708 | return 0; | |
1709 | } | |
1710 | ||
34dd82af | 1711 | static int loop_lookup(struct loop_device **l, int i) |
a47653fc KC |
1712 | { |
1713 | struct loop_device *lo; | |
34dd82af | 1714 | int ret = -ENODEV; |
a47653fc | 1715 | |
770fe30a KS |
1716 | if (i < 0) { |
1717 | int err; | |
1718 | ||
1719 | err = idr_for_each(&loop_index_idr, &find_free_cb, &lo); | |
1720 | if (err == 1) { | |
1721 | *l = lo; | |
1722 | ret = lo->lo_number; | |
1723 | } | |
1724 | goto out; | |
a47653fc KC |
1725 | } |
1726 | ||
770fe30a | 1727 | /* lookup and return a specific i */ |
34dd82af | 1728 | lo = idr_find(&loop_index_idr, i); |
a47653fc | 1729 | if (lo) { |
34dd82af KS |
1730 | *l = lo; |
1731 | ret = lo->lo_number; | |
a47653fc | 1732 | } |
770fe30a | 1733 | out: |
34dd82af | 1734 | return ret; |
a47653fc KC |
1735 | } |
1736 | ||
73285082 KC |
1737 | static struct kobject *loop_probe(dev_t dev, int *part, void *data) |
1738 | { | |
705962cc | 1739 | struct loop_device *lo; |
07002e99 | 1740 | struct kobject *kobj; |
34dd82af | 1741 | int err; |
73285082 | 1742 | |
34dd82af KS |
1743 | mutex_lock(&loop_index_mutex); |
1744 | err = loop_lookup(&lo, MINOR(dev) >> part_shift); | |
1745 | if (err < 0) | |
1746 | err = loop_add(&lo, MINOR(dev) >> part_shift); | |
1747 | if (err < 0) | |
1748 | kobj = ERR_PTR(err); | |
1749 | else | |
1750 | kobj = get_disk(lo->lo_disk); | |
1751 | mutex_unlock(&loop_index_mutex); | |
73285082 KC |
1752 | |
1753 | *part = 0; | |
07002e99 | 1754 | return kobj; |
73285082 KC |
1755 | } |
1756 | ||
770fe30a KS |
1757 | static long loop_control_ioctl(struct file *file, unsigned int cmd, |
1758 | unsigned long parm) | |
1759 | { | |
1760 | struct loop_device *lo; | |
1761 | int ret = -ENOSYS; | |
1762 | ||
1763 | mutex_lock(&loop_index_mutex); | |
1764 | switch (cmd) { | |
1765 | case LOOP_CTL_ADD: | |
1766 | ret = loop_lookup(&lo, parm); | |
1767 | if (ret >= 0) { | |
1768 | ret = -EEXIST; | |
1769 | break; | |
1770 | } | |
1771 | ret = loop_add(&lo, parm); | |
1772 | break; | |
1773 | case LOOP_CTL_REMOVE: | |
1774 | ret = loop_lookup(&lo, parm); | |
1775 | if (ret < 0) | |
1776 | break; | |
1777 | mutex_lock(&lo->lo_ctl_mutex); | |
1778 | if (lo->lo_state != Lo_unbound) { | |
1779 | ret = -EBUSY; | |
1780 | mutex_unlock(&lo->lo_ctl_mutex); | |
1781 | break; | |
1782 | } | |
1783 | if (lo->lo_refcnt > 0) { | |
1784 | ret = -EBUSY; | |
1785 | mutex_unlock(&lo->lo_ctl_mutex); | |
1786 | break; | |
1787 | } | |
1788 | lo->lo_disk->private_data = NULL; | |
1789 | mutex_unlock(&lo->lo_ctl_mutex); | |
1790 | idr_remove(&loop_index_idr, lo->lo_number); | |
1791 | loop_remove(lo); | |
1792 | break; | |
1793 | case LOOP_CTL_GET_FREE: | |
1794 | ret = loop_lookup(&lo, -1); | |
1795 | if (ret >= 0) | |
1796 | break; | |
1797 | ret = loop_add(&lo, -1); | |
1798 | } | |
1799 | mutex_unlock(&loop_index_mutex); | |
1800 | ||
1801 | return ret; | |
1802 | } | |
1803 | ||
1804 | static const struct file_operations loop_ctl_fops = { | |
1805 | .open = nonseekable_open, | |
1806 | .unlocked_ioctl = loop_control_ioctl, | |
1807 | .compat_ioctl = loop_control_ioctl, | |
1808 | .owner = THIS_MODULE, | |
1809 | .llseek = noop_llseek, | |
1810 | }; | |
1811 | ||
1812 | static struct miscdevice loop_misc = { | |
1813 | .minor = LOOP_CTRL_MINOR, | |
1814 | .name = "loop-control", | |
1815 | .fops = &loop_ctl_fops, | |
1816 | }; | |
1817 | ||
1818 | MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR); | |
1819 | MODULE_ALIAS("devname:loop-control"); | |
1820 | ||
73285082 KC |
1821 | static int __init loop_init(void) |
1822 | { | |
a47653fc KC |
1823 | int i, nr; |
1824 | unsigned long range; | |
34dd82af | 1825 | struct loop_device *lo; |
770fe30a | 1826 | int err; |
a47653fc | 1827 | |
770fe30a KS |
1828 | err = misc_register(&loop_misc); |
1829 | if (err < 0) | |
1830 | return err; | |
476a4813 LV |
1831 | |
1832 | part_shift = 0; | |
ac04fee0 | 1833 | if (max_part > 0) { |
476a4813 LV |
1834 | part_shift = fls(max_part); |
1835 | ||
ac04fee0 NK |
1836 | /* |
1837 | * Adjust max_part according to part_shift as it is exported | |
1838 | * to user space so that user can decide correct minor number | |
1839 | * if [s]he want to create more devices. | |
1840 | * | |
1841 | * Note that -1 is required because partition 0 is reserved | |
1842 | * for the whole disk. | |
1843 | */ | |
1844 | max_part = (1UL << part_shift) - 1; | |
1845 | } | |
1846 | ||
78f4bb36 NK |
1847 | if ((1UL << part_shift) > DISK_MAX_PARTS) |
1848 | return -EINVAL; | |
1849 | ||
476a4813 | 1850 | if (max_loop > 1UL << (MINORBITS - part_shift)) |
a47653fc | 1851 | return -EINVAL; |
1da177e4 | 1852 | |
d134b00b KS |
1853 | /* |
1854 | * If max_loop is specified, create that many devices upfront. | |
1855 | * This also becomes a hard limit. If max_loop is not specified, | |
1856 | * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module | |
1857 | * init time. Loop devices can be requested on-demand with the | |
1858 | * /dev/loop-control interface, or be instantiated by accessing | |
1859 | * a 'dead' device node. | |
1860 | */ | |
73285082 | 1861 | if (max_loop) { |
a47653fc | 1862 | nr = max_loop; |
a1c15c59 | 1863 | range = max_loop << part_shift; |
a47653fc | 1864 | } else { |
d134b00b | 1865 | nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; |
a1c15c59 | 1866 | range = 1UL << MINORBITS; |
a47653fc KC |
1867 | } |
1868 | ||
1869 | if (register_blkdev(LOOP_MAJOR, "loop")) | |
1870 | return -EIO; | |
1da177e4 | 1871 | |
a47653fc KC |
1872 | blk_register_region(MKDEV(LOOP_MAJOR, 0), range, |
1873 | THIS_MODULE, loop_probe, NULL, NULL); | |
1874 | ||
d134b00b | 1875 | /* pre-create number of devices given by config or max_loop */ |
34dd82af KS |
1876 | mutex_lock(&loop_index_mutex); |
1877 | for (i = 0; i < nr; i++) | |
1878 | loop_add(&lo, i); | |
1879 | mutex_unlock(&loop_index_mutex); | |
1880 | ||
73285082 | 1881 | printk(KERN_INFO "loop: module loaded\n"); |
1da177e4 | 1882 | return 0; |
34dd82af | 1883 | } |
a47653fc | 1884 | |
34dd82af KS |
1885 | static int loop_exit_cb(int id, void *ptr, void *data) |
1886 | { | |
1887 | struct loop_device *lo = ptr; | |
a47653fc | 1888 | |
34dd82af KS |
1889 | loop_remove(lo); |
1890 | return 0; | |
1da177e4 LT |
1891 | } |
1892 | ||
73285082 | 1893 | static void __exit loop_exit(void) |
1da177e4 | 1894 | { |
a47653fc | 1895 | unsigned long range; |
1da177e4 | 1896 | |
a1c15c59 | 1897 | range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; |
a47653fc | 1898 | |
34dd82af KS |
1899 | idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); |
1900 | idr_remove_all(&loop_index_idr); | |
1901 | idr_destroy(&loop_index_idr); | |
73285082 | 1902 | |
a47653fc | 1903 | blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); |
00d59405 | 1904 | unregister_blkdev(LOOP_MAJOR, "loop"); |
770fe30a KS |
1905 | |
1906 | misc_deregister(&loop_misc); | |
1da177e4 LT |
1907 | } |
1908 | ||
1909 | module_init(loop_init); | |
1910 | module_exit(loop_exit); | |
1911 | ||
1912 | #ifndef MODULE | |
1913 | static int __init max_loop_setup(char *str) | |
1914 | { | |
1915 | max_loop = simple_strtol(str, NULL, 0); | |
1916 | return 1; | |
1917 | } | |
1918 | ||
1919 | __setup("max_loop=", max_loop_setup); | |
1920 | #endif |