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> | |
863d5b82 | 66 | #include <linux/compat.h> |
1da177e4 | 67 | #include <linux/suspend.h> |
83144186 | 68 | #include <linux/freezer.h> |
2a48fc0a | 69 | #include <linux/mutex.h> |
1da177e4 | 70 | #include <linux/writeback.h> |
1da177e4 LT |
71 | #include <linux/completion.h> |
72 | #include <linux/highmem.h> | |
6c997918 | 73 | #include <linux/kthread.h> |
d6b29d7c | 74 | #include <linux/splice.h> |
ee862730 | 75 | #include <linux/sysfs.h> |
770fe30a | 76 | #include <linux/miscdevice.h> |
dfaa2ef6 | 77 | #include <linux/falloc.h> |
83a87611 | 78 | #include "loop.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 | ||
b5dd2f60 ML |
88 | static struct workqueue_struct *loop_wq; |
89 | ||
1da177e4 LT |
90 | /* |
91 | * Transfer functions | |
92 | */ | |
93 | static int transfer_none(struct loop_device *lo, int cmd, | |
94 | struct page *raw_page, unsigned raw_off, | |
95 | struct page *loop_page, unsigned loop_off, | |
96 | int size, sector_t real_block) | |
97 | { | |
cfd8005c CW |
98 | char *raw_buf = kmap_atomic(raw_page) + raw_off; |
99 | char *loop_buf = kmap_atomic(loop_page) + loop_off; | |
1da177e4 LT |
100 | |
101 | if (cmd == READ) | |
102 | memcpy(loop_buf, raw_buf, size); | |
103 | else | |
104 | memcpy(raw_buf, loop_buf, size); | |
105 | ||
cfd8005c CW |
106 | kunmap_atomic(loop_buf); |
107 | kunmap_atomic(raw_buf); | |
1da177e4 LT |
108 | cond_resched(); |
109 | return 0; | |
110 | } | |
111 | ||
112 | static int transfer_xor(struct loop_device *lo, int cmd, | |
113 | struct page *raw_page, unsigned raw_off, | |
114 | struct page *loop_page, unsigned loop_off, | |
115 | int size, sector_t real_block) | |
116 | { | |
cfd8005c CW |
117 | char *raw_buf = kmap_atomic(raw_page) + raw_off; |
118 | char *loop_buf = kmap_atomic(loop_page) + loop_off; | |
1da177e4 LT |
119 | char *in, *out, *key; |
120 | int i, keysize; | |
121 | ||
122 | if (cmd == READ) { | |
123 | in = raw_buf; | |
124 | out = loop_buf; | |
125 | } else { | |
126 | in = loop_buf; | |
127 | out = raw_buf; | |
128 | } | |
129 | ||
130 | key = lo->lo_encrypt_key; | |
131 | keysize = lo->lo_encrypt_key_size; | |
132 | for (i = 0; i < size; i++) | |
133 | *out++ = *in++ ^ key[(i & 511) % keysize]; | |
134 | ||
cfd8005c CW |
135 | kunmap_atomic(loop_buf); |
136 | kunmap_atomic(raw_buf); | |
1da177e4 LT |
137 | cond_resched(); |
138 | return 0; | |
139 | } | |
140 | ||
141 | static int xor_init(struct loop_device *lo, const struct loop_info64 *info) | |
142 | { | |
143 | if (unlikely(info->lo_encrypt_key_size <= 0)) | |
144 | return -EINVAL; | |
145 | return 0; | |
146 | } | |
147 | ||
148 | static struct loop_func_table none_funcs = { | |
149 | .number = LO_CRYPT_NONE, | |
150 | .transfer = transfer_none, | |
151 | }; | |
152 | ||
153 | static struct loop_func_table xor_funcs = { | |
154 | .number = LO_CRYPT_XOR, | |
155 | .transfer = transfer_xor, | |
156 | .init = xor_init | |
157 | }; | |
158 | ||
159 | /* xfer_funcs[0] is special - its release function is never called */ | |
160 | static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { | |
161 | &none_funcs, | |
162 | &xor_funcs | |
163 | }; | |
164 | ||
7035b5df | 165 | static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) |
1da177e4 | 166 | { |
b7a1da69 | 167 | loff_t loopsize; |
1da177e4 LT |
168 | |
169 | /* Compute loopsize in bytes */ | |
b7a1da69 GC |
170 | loopsize = i_size_read(file->f_mapping->host); |
171 | if (offset > 0) | |
172 | loopsize -= offset; | |
173 | /* offset is beyond i_size, weird but possible */ | |
7035b5df DM |
174 | if (loopsize < 0) |
175 | return 0; | |
1da177e4 | 176 | |
7035b5df DM |
177 | if (sizelimit > 0 && sizelimit < loopsize) |
178 | loopsize = sizelimit; | |
1da177e4 LT |
179 | /* |
180 | * Unfortunately, if we want to do I/O on the device, | |
181 | * the number of 512-byte sectors has to fit into a sector_t. | |
182 | */ | |
183 | return loopsize >> 9; | |
184 | } | |
185 | ||
7035b5df DM |
186 | static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
187 | { | |
188 | return get_size(lo->lo_offset, lo->lo_sizelimit, file); | |
189 | } | |
190 | ||
1da177e4 | 191 | static int |
7035b5df | 192 | figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) |
1da177e4 | 193 | { |
7035b5df | 194 | loff_t size = get_size(offset, sizelimit, lo->lo_backing_file); |
1da177e4 | 195 | sector_t x = (sector_t)size; |
7b0576a3 | 196 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
197 | |
198 | if (unlikely((loff_t)x != size)) | |
199 | return -EFBIG; | |
7035b5df DM |
200 | if (lo->lo_offset != offset) |
201 | lo->lo_offset = offset; | |
202 | if (lo->lo_sizelimit != sizelimit) | |
203 | lo->lo_sizelimit = sizelimit; | |
73285082 | 204 | set_capacity(lo->lo_disk, x); |
7b0576a3 GC |
205 | bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9); |
206 | /* let user-space know about the new size */ | |
207 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
7035b5df | 208 | return 0; |
1da177e4 LT |
209 | } |
210 | ||
211 | static inline int | |
212 | lo_do_transfer(struct loop_device *lo, int cmd, | |
213 | struct page *rpage, unsigned roffs, | |
214 | struct page *lpage, unsigned loffs, | |
215 | int size, sector_t rblock) | |
216 | { | |
217 | if (unlikely(!lo->transfer)) | |
218 | return 0; | |
219 | ||
220 | return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); | |
221 | } | |
222 | ||
1da177e4 LT |
223 | /** |
224 | * __do_lo_send_write - helper for writing data to a loop device | |
225 | * | |
226 | * This helper just factors out common code between do_lo_send_direct_write() | |
227 | * and do_lo_send_write(). | |
228 | */ | |
858119e1 | 229 | static int __do_lo_send_write(struct file *file, |
98ae6ccd | 230 | u8 *buf, const int len, loff_t pos) |
1da177e4 LT |
231 | { |
232 | ssize_t bw; | |
233 | mm_segment_t old_fs = get_fs(); | |
234 | ||
03d95eb2 | 235 | file_start_write(file); |
1da177e4 LT |
236 | set_fs(get_ds()); |
237 | bw = file->f_op->write(file, buf, len, &pos); | |
238 | set_fs(old_fs); | |
03d95eb2 | 239 | file_end_write(file); |
1da177e4 LT |
240 | if (likely(bw == len)) |
241 | return 0; | |
44bd70c3 | 242 | printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", |
1da177e4 LT |
243 | (unsigned long long)pos, len); |
244 | if (bw >= 0) | |
245 | bw = -EIO; | |
246 | return bw; | |
247 | } | |
248 | ||
249 | /** | |
250 | * do_lo_send_direct_write - helper for writing data to a loop device | |
251 | * | |
456be148 CH |
252 | * This is the fast, non-transforming version that does not need double |
253 | * buffering. | |
1da177e4 LT |
254 | */ |
255 | static int do_lo_send_direct_write(struct loop_device *lo, | |
511de73f | 256 | struct bio_vec *bvec, loff_t pos, struct page *page) |
1da177e4 LT |
257 | { |
258 | ssize_t bw = __do_lo_send_write(lo->lo_backing_file, | |
98ae6ccd | 259 | kmap(bvec->bv_page) + bvec->bv_offset, |
1da177e4 LT |
260 | bvec->bv_len, pos); |
261 | kunmap(bvec->bv_page); | |
262 | cond_resched(); | |
263 | return bw; | |
264 | } | |
265 | ||
266 | /** | |
267 | * do_lo_send_write - helper for writing data to a loop device | |
268 | * | |
456be148 CH |
269 | * This is the slow, transforming version that needs to double buffer the |
270 | * data as it cannot do the transformations in place without having direct | |
271 | * access to the destination pages of the backing file. | |
1da177e4 LT |
272 | */ |
273 | static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, | |
511de73f | 274 | loff_t pos, struct page *page) |
1da177e4 LT |
275 | { |
276 | int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, | |
277 | bvec->bv_offset, bvec->bv_len, pos >> 9); | |
278 | if (likely(!ret)) | |
279 | return __do_lo_send_write(lo->lo_backing_file, | |
98ae6ccd | 280 | page_address(page), bvec->bv_len, |
1da177e4 | 281 | pos); |
44bd70c3 | 282 | printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, " |
1da177e4 LT |
283 | "length %i.\n", (unsigned long long)pos, bvec->bv_len); |
284 | if (ret > 0) | |
285 | ret = -EIO; | |
286 | return ret; | |
287 | } | |
288 | ||
30112013 | 289 | static int lo_send(struct loop_device *lo, struct request *rq, loff_t pos) |
1da177e4 | 290 | { |
511de73f | 291 | int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t, |
1da177e4 | 292 | struct page *page); |
7988613b | 293 | struct bio_vec bvec; |
30112013 | 294 | struct req_iterator iter; |
1da177e4 | 295 | struct page *page = NULL; |
7988613b | 296 | int ret = 0; |
1da177e4 | 297 | |
456be148 CH |
298 | if (lo->transfer != transfer_none) { |
299 | page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); | |
300 | if (unlikely(!page)) | |
301 | goto fail; | |
302 | kmap(page); | |
303 | do_lo_send = do_lo_send_write; | |
304 | } else { | |
1da177e4 | 305 | do_lo_send = do_lo_send_direct_write; |
1da177e4 | 306 | } |
456be148 | 307 | |
30112013 | 308 | rq_for_each_segment(bvec, rq, iter) { |
7988613b | 309 | ret = do_lo_send(lo, &bvec, pos, page); |
1da177e4 LT |
310 | if (ret < 0) |
311 | break; | |
7988613b | 312 | pos += bvec.bv_len; |
1da177e4 LT |
313 | } |
314 | if (page) { | |
315 | kunmap(page); | |
316 | __free_page(page); | |
317 | } | |
318 | out: | |
319 | return ret; | |
320 | fail: | |
44bd70c3 | 321 | printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); |
1da177e4 LT |
322 | ret = -ENOMEM; |
323 | goto out; | |
324 | } | |
325 | ||
326 | struct lo_read_data { | |
327 | struct loop_device *lo; | |
328 | struct page *page; | |
329 | unsigned offset; | |
330 | int bsize; | |
331 | }; | |
332 | ||
333 | static int | |
fd582140 JA |
334 | lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
335 | struct splice_desc *sd) | |
1da177e4 | 336 | { |
fd582140 | 337 | struct lo_read_data *p = sd->u.data; |
1da177e4 | 338 | struct loop_device *lo = p->lo; |
fd582140 | 339 | struct page *page = buf->page; |
1da177e4 | 340 | sector_t IV; |
3603b8ea | 341 | int size; |
1da177e4 | 342 | |
fd582140 JA |
343 | IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) + |
344 | (buf->offset >> 9); | |
345 | size = sd->len; | |
346 | if (size > p->bsize) | |
347 | size = p->bsize; | |
1da177e4 | 348 | |
fd582140 | 349 | if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) { |
44bd70c3 | 350 | printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n", |
1da177e4 | 351 | page->index); |
fd582140 | 352 | size = -EINVAL; |
1da177e4 LT |
353 | } |
354 | ||
355 | flush_dcache_page(p->page); | |
356 | ||
fd582140 JA |
357 | if (size > 0) |
358 | p->offset += size; | |
359 | ||
1da177e4 LT |
360 | return size; |
361 | } | |
362 | ||
fd582140 JA |
363 | static int |
364 | lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) | |
365 | { | |
366 | return __splice_from_pipe(pipe, sd, lo_splice_actor); | |
367 | } | |
368 | ||
306df071 | 369 | static ssize_t |
1da177e4 LT |
370 | do_lo_receive(struct loop_device *lo, |
371 | struct bio_vec *bvec, int bsize, loff_t pos) | |
372 | { | |
373 | struct lo_read_data cookie; | |
fd582140 | 374 | struct splice_desc sd; |
1da177e4 | 375 | struct file *file; |
306df071 | 376 | ssize_t retval; |
1da177e4 LT |
377 | |
378 | cookie.lo = lo; | |
379 | cookie.page = bvec->bv_page; | |
380 | cookie.offset = bvec->bv_offset; | |
381 | cookie.bsize = bsize; | |
fd582140 JA |
382 | |
383 | sd.len = 0; | |
384 | sd.total_len = bvec->bv_len; | |
385 | sd.flags = 0; | |
386 | sd.pos = pos; | |
387 | sd.u.data = &cookie; | |
388 | ||
1da177e4 | 389 | file = lo->lo_backing_file; |
fd582140 JA |
390 | retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor); |
391 | ||
306df071 | 392 | return retval; |
1da177e4 LT |
393 | } |
394 | ||
395 | static int | |
30112013 | 396 | lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos) |
1da177e4 | 397 | { |
7988613b | 398 | struct bio_vec bvec; |
30112013 | 399 | struct req_iterator iter; |
306df071 | 400 | ssize_t s; |
1da177e4 | 401 | |
30112013 | 402 | rq_for_each_segment(bvec, rq, iter) { |
7988613b | 403 | s = do_lo_receive(lo, &bvec, bsize, pos); |
306df071 DY |
404 | if (s < 0) |
405 | return s; | |
406 | ||
7988613b | 407 | if (s != bvec.bv_len) { |
30112013 ML |
408 | struct bio *bio; |
409 | ||
410 | __rq_for_each_bio(bio, rq) | |
411 | zero_fill_bio(bio); | |
1da177e4 | 412 | break; |
306df071 | 413 | } |
7988613b | 414 | pos += bvec.bv_len; |
1da177e4 | 415 | } |
306df071 | 416 | return 0; |
1da177e4 LT |
417 | } |
418 | ||
cf655d95 ML |
419 | static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos) |
420 | { | |
421 | /* | |
422 | * We use punch hole to reclaim the free space used by the | |
423 | * image a.k.a. discard. However we do not support discard if | |
424 | * encryption is enabled, because it may give an attacker | |
425 | * useful information. | |
426 | */ | |
427 | struct file *file = lo->lo_backing_file; | |
428 | int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE; | |
429 | int ret; | |
430 | ||
431 | if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { | |
432 | ret = -EOPNOTSUPP; | |
433 | goto out; | |
434 | } | |
435 | ||
436 | ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); | |
437 | if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) | |
438 | ret = -EIO; | |
439 | out: | |
440 | return ret; | |
441 | } | |
442 | ||
443 | static int lo_req_flush(struct loop_device *lo, struct request *rq) | |
444 | { | |
445 | struct file *file = lo->lo_backing_file; | |
446 | int ret = vfs_fsync(file, 0); | |
447 | if (unlikely(ret && ret != -EINVAL)) | |
448 | ret = -EIO; | |
449 | ||
450 | return ret; | |
451 | } | |
452 | ||
30112013 | 453 | static int do_req_filebacked(struct loop_device *lo, struct request *rq) |
1da177e4 LT |
454 | { |
455 | loff_t pos; | |
456 | int ret; | |
457 | ||
30112013 | 458 | pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; |
68db1961 | 459 | |
30112013 | 460 | if (rq->cmd_flags & REQ_WRITE) { |
cf655d95 ML |
461 | if (rq->cmd_flags & REQ_FLUSH) |
462 | ret = lo_req_flush(lo, rq); | |
af65aa8e | 463 | else if (rq->cmd_flags & REQ_DISCARD) |
cf655d95 | 464 | ret = lo_discard(lo, rq, pos); |
af65aa8e ML |
465 | else |
466 | ret = lo_send(lo, rq, pos); | |
68db1961 | 467 | } else |
30112013 | 468 | ret = lo_receive(lo, rq, lo->lo_blocksize, pos); |
68db1961 | 469 | |
1da177e4 LT |
470 | return ret; |
471 | } | |
472 | ||
1da177e4 LT |
473 | struct switch_request { |
474 | struct file *file; | |
475 | struct completion wait; | |
476 | }; | |
477 | ||
1da177e4 | 478 | /* |
b5dd2f60 | 479 | * Do the actual switch; called from the BIO completion routine |
1da177e4 | 480 | */ |
b5dd2f60 | 481 | static void do_loop_switch(struct loop_device *lo, struct switch_request *p) |
1da177e4 | 482 | { |
b5dd2f60 ML |
483 | struct file *file = p->file; |
484 | struct file *old_file = lo->lo_backing_file; | |
485 | struct address_space *mapping; | |
35a82d1a | 486 | |
b5dd2f60 ML |
487 | /* if no new file, only flush of queued bios requested */ |
488 | if (!file) | |
489 | return; | |
1da177e4 | 490 | |
b5dd2f60 ML |
491 | mapping = file->f_mapping; |
492 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); | |
493 | lo->lo_backing_file = file; | |
494 | lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ? | |
495 | mapping->host->i_bdev->bd_block_size : PAGE_SIZE; | |
496 | lo->old_gfp_mask = mapping_gfp_mask(mapping); | |
497 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
1da177e4 LT |
498 | } |
499 | ||
500 | /* | |
501 | * loop_switch performs the hard work of switching a backing store. | |
502 | * First it needs to flush existing IO, it does this by sending a magic | |
503 | * BIO down the pipe. The completion of this BIO does the actual switch. | |
504 | */ | |
505 | static int loop_switch(struct loop_device *lo, struct file *file) | |
506 | { | |
507 | struct switch_request w; | |
b5dd2f60 | 508 | |
1da177e4 | 509 | w.file = file; |
b5dd2f60 ML |
510 | |
511 | /* freeze queue and wait for completion of scheduled requests */ | |
512 | blk_mq_freeze_queue(lo->lo_queue); | |
513 | ||
514 | /* do the switch action */ | |
515 | do_loop_switch(lo, &w); | |
516 | ||
517 | /* unfreeze */ | |
518 | blk_mq_unfreeze_queue(lo->lo_queue); | |
519 | ||
1da177e4 LT |
520 | return 0; |
521 | } | |
522 | ||
14f27939 MB |
523 | /* |
524 | * Helper to flush the IOs in loop, but keeping loop thread running | |
525 | */ | |
526 | static int loop_flush(struct loop_device *lo) | |
527 | { | |
14f27939 MB |
528 | return loop_switch(lo, NULL); |
529 | } | |
530 | ||
1da177e4 LT |
531 | /* |
532 | * loop_change_fd switched the backing store of a loopback device to | |
533 | * a new file. This is useful for operating system installers to free up | |
534 | * the original file and in High Availability environments to switch to | |
535 | * an alternative location for the content in case of server meltdown. | |
536 | * This can only work if the loop device is used read-only, and if the | |
537 | * new backing store is the same size and type as the old backing store. | |
538 | */ | |
bb214884 AV |
539 | static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
540 | unsigned int arg) | |
1da177e4 LT |
541 | { |
542 | struct file *file, *old_file; | |
543 | struct inode *inode; | |
544 | int error; | |
545 | ||
546 | error = -ENXIO; | |
547 | if (lo->lo_state != Lo_bound) | |
548 | goto out; | |
549 | ||
550 | /* the loop device has to be read-only */ | |
551 | error = -EINVAL; | |
552 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) | |
553 | goto out; | |
554 | ||
555 | error = -EBADF; | |
556 | file = fget(arg); | |
557 | if (!file) | |
558 | goto out; | |
559 | ||
560 | inode = file->f_mapping->host; | |
561 | old_file = lo->lo_backing_file; | |
562 | ||
563 | error = -EINVAL; | |
564 | ||
565 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
566 | goto out_putf; | |
567 | ||
1da177e4 LT |
568 | /* size of the new backing store needs to be the same */ |
569 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) | |
570 | goto out_putf; | |
571 | ||
572 | /* and ... switch */ | |
573 | error = loop_switch(lo, file); | |
574 | if (error) | |
575 | goto out_putf; | |
576 | ||
577 | fput(old_file); | |
e03c8dd1 | 578 | if (lo->lo_flags & LO_FLAGS_PARTSCAN) |
476a4813 | 579 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
1da177e4 LT |
580 | return 0; |
581 | ||
582 | out_putf: | |
583 | fput(file); | |
584 | out: | |
585 | return error; | |
586 | } | |
587 | ||
588 | static inline int is_loop_device(struct file *file) | |
589 | { | |
590 | struct inode *i = file->f_mapping->host; | |
591 | ||
592 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; | |
593 | } | |
594 | ||
ee862730 MB |
595 | /* loop sysfs attributes */ |
596 | ||
597 | static ssize_t loop_attr_show(struct device *dev, char *page, | |
598 | ssize_t (*callback)(struct loop_device *, char *)) | |
599 | { | |
34dd82af KS |
600 | struct gendisk *disk = dev_to_disk(dev); |
601 | struct loop_device *lo = disk->private_data; | |
ee862730 | 602 | |
34dd82af | 603 | return callback(lo, page); |
ee862730 MB |
604 | } |
605 | ||
606 | #define LOOP_ATTR_RO(_name) \ | |
607 | static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ | |
608 | static ssize_t loop_attr_do_show_##_name(struct device *d, \ | |
609 | struct device_attribute *attr, char *b) \ | |
610 | { \ | |
611 | return loop_attr_show(d, b, loop_attr_##_name##_show); \ | |
612 | } \ | |
613 | static struct device_attribute loop_attr_##_name = \ | |
614 | __ATTR(_name, S_IRUGO, loop_attr_do_show_##_name, NULL); | |
615 | ||
616 | static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) | |
617 | { | |
618 | ssize_t ret; | |
619 | char *p = NULL; | |
620 | ||
05eb0f25 | 621 | spin_lock_irq(&lo->lo_lock); |
ee862730 MB |
622 | if (lo->lo_backing_file) |
623 | p = d_path(&lo->lo_backing_file->f_path, buf, PAGE_SIZE - 1); | |
05eb0f25 | 624 | spin_unlock_irq(&lo->lo_lock); |
ee862730 MB |
625 | |
626 | if (IS_ERR_OR_NULL(p)) | |
627 | ret = PTR_ERR(p); | |
628 | else { | |
629 | ret = strlen(p); | |
630 | memmove(buf, p, ret); | |
631 | buf[ret++] = '\n'; | |
632 | buf[ret] = 0; | |
633 | } | |
634 | ||
635 | return ret; | |
636 | } | |
637 | ||
638 | static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) | |
639 | { | |
640 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); | |
641 | } | |
642 | ||
643 | static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) | |
644 | { | |
645 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); | |
646 | } | |
647 | ||
648 | static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) | |
649 | { | |
650 | int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); | |
651 | ||
652 | return sprintf(buf, "%s\n", autoclear ? "1" : "0"); | |
653 | } | |
654 | ||
e03c8dd1 KS |
655 | static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf) |
656 | { | |
657 | int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN); | |
658 | ||
659 | return sprintf(buf, "%s\n", partscan ? "1" : "0"); | |
660 | } | |
661 | ||
ee862730 MB |
662 | LOOP_ATTR_RO(backing_file); |
663 | LOOP_ATTR_RO(offset); | |
664 | LOOP_ATTR_RO(sizelimit); | |
665 | LOOP_ATTR_RO(autoclear); | |
e03c8dd1 | 666 | LOOP_ATTR_RO(partscan); |
ee862730 MB |
667 | |
668 | static struct attribute *loop_attrs[] = { | |
669 | &loop_attr_backing_file.attr, | |
670 | &loop_attr_offset.attr, | |
671 | &loop_attr_sizelimit.attr, | |
672 | &loop_attr_autoclear.attr, | |
e03c8dd1 | 673 | &loop_attr_partscan.attr, |
ee862730 MB |
674 | NULL, |
675 | }; | |
676 | ||
677 | static struct attribute_group loop_attribute_group = { | |
678 | .name = "loop", | |
679 | .attrs= loop_attrs, | |
680 | }; | |
681 | ||
682 | static int loop_sysfs_init(struct loop_device *lo) | |
683 | { | |
684 | return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, | |
685 | &loop_attribute_group); | |
686 | } | |
687 | ||
688 | static void loop_sysfs_exit(struct loop_device *lo) | |
689 | { | |
690 | sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, | |
691 | &loop_attribute_group); | |
692 | } | |
693 | ||
dfaa2ef6 LC |
694 | static void loop_config_discard(struct loop_device *lo) |
695 | { | |
696 | struct file *file = lo->lo_backing_file; | |
697 | struct inode *inode = file->f_mapping->host; | |
698 | struct request_queue *q = lo->lo_queue; | |
699 | ||
700 | /* | |
701 | * We use punch hole to reclaim the free space used by the | |
12a64d2f | 702 | * image a.k.a. discard. However we do not support discard if |
dfaa2ef6 LC |
703 | * encryption is enabled, because it may give an attacker |
704 | * useful information. | |
705 | */ | |
706 | if ((!file->f_op->fallocate) || | |
707 | lo->lo_encrypt_key_size) { | |
708 | q->limits.discard_granularity = 0; | |
709 | q->limits.discard_alignment = 0; | |
710 | q->limits.max_discard_sectors = 0; | |
711 | q->limits.discard_zeroes_data = 0; | |
712 | queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q); | |
713 | return; | |
714 | } | |
715 | ||
716 | q->limits.discard_granularity = inode->i_sb->s_blocksize; | |
dfaf3c03 | 717 | q->limits.discard_alignment = 0; |
dfaa2ef6 LC |
718 | q->limits.max_discard_sectors = UINT_MAX >> 9; |
719 | q->limits.discard_zeroes_data = 1; | |
720 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); | |
721 | } | |
722 | ||
bb214884 | 723 | static int loop_set_fd(struct loop_device *lo, fmode_t mode, |
1da177e4 LT |
724 | struct block_device *bdev, unsigned int arg) |
725 | { | |
726 | struct file *file, *f; | |
727 | struct inode *inode; | |
728 | struct address_space *mapping; | |
729 | unsigned lo_blocksize; | |
730 | int lo_flags = 0; | |
731 | int error; | |
732 | loff_t size; | |
733 | ||
734 | /* This is safe, since we have a reference from open(). */ | |
735 | __module_get(THIS_MODULE); | |
736 | ||
737 | error = -EBADF; | |
738 | file = fget(arg); | |
739 | if (!file) | |
740 | goto out; | |
741 | ||
742 | error = -EBUSY; | |
743 | if (lo->lo_state != Lo_unbound) | |
744 | goto out_putf; | |
745 | ||
746 | /* Avoid recursion */ | |
747 | f = file; | |
748 | while (is_loop_device(f)) { | |
749 | struct loop_device *l; | |
750 | ||
bb214884 | 751 | if (f->f_mapping->host->i_bdev == bdev) |
1da177e4 LT |
752 | goto out_putf; |
753 | ||
754 | l = f->f_mapping->host->i_bdev->bd_disk->private_data; | |
755 | if (l->lo_state == Lo_unbound) { | |
756 | error = -EINVAL; | |
757 | goto out_putf; | |
758 | } | |
759 | f = l->lo_backing_file; | |
760 | } | |
761 | ||
762 | mapping = file->f_mapping; | |
763 | inode = mapping->host; | |
764 | ||
1da177e4 | 765 | error = -EINVAL; |
456be148 CH |
766 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
767 | goto out_putf; | |
1da177e4 | 768 | |
456be148 CH |
769 | if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || |
770 | !file->f_op->write) | |
771 | lo_flags |= LO_FLAGS_READ_ONLY; | |
ba52de12 | 772 | |
456be148 CH |
773 | lo_blocksize = S_ISBLK(inode->i_mode) ? |
774 | inode->i_bdev->bd_block_size : PAGE_SIZE; | |
1da177e4 | 775 | |
456be148 | 776 | error = -EFBIG; |
1da177e4 | 777 | size = get_loop_size(lo, file); |
456be148 | 778 | if ((loff_t)(sector_t)size != size) |
1da177e4 | 779 | goto out_putf; |
1da177e4 | 780 | |
456be148 | 781 | error = 0; |
1da177e4 LT |
782 | |
783 | set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); | |
784 | ||
785 | lo->lo_blocksize = lo_blocksize; | |
786 | lo->lo_device = bdev; | |
787 | lo->lo_flags = lo_flags; | |
788 | lo->lo_backing_file = file; | |
eefe85ee | 789 | lo->transfer = transfer_none; |
1da177e4 LT |
790 | lo->ioctl = NULL; |
791 | lo->lo_sizelimit = 0; | |
792 | lo->old_gfp_mask = mapping_gfp_mask(mapping); | |
793 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
794 | ||
68db1961 | 795 | if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
4913efe4 | 796 | blk_queue_flush(lo->lo_queue, REQ_FLUSH); |
68db1961 | 797 | |
73285082 | 798 | set_capacity(lo->lo_disk, size); |
1da177e4 | 799 | bd_set_size(bdev, size << 9); |
ee862730 | 800 | loop_sysfs_init(lo); |
c3473c63 DZ |
801 | /* let user-space know about the new size */ |
802 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1da177e4 LT |
803 | |
804 | set_blocksize(bdev, lo_blocksize); | |
805 | ||
6c997918 | 806 | lo->lo_state = Lo_bound; |
e03c8dd1 KS |
807 | if (part_shift) |
808 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
809 | if (lo->lo_flags & LO_FLAGS_PARTSCAN) | |
476a4813 | 810 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
c1681bf8 AP |
811 | |
812 | /* Grab the block_device to prevent its destruction after we | |
813 | * put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev). | |
814 | */ | |
815 | bdgrab(bdev); | |
1da177e4 LT |
816 | return 0; |
817 | ||
818 | out_putf: | |
819 | fput(file); | |
820 | out: | |
821 | /* This is safe: open() is still holding a reference. */ | |
822 | module_put(THIS_MODULE); | |
823 | return error; | |
824 | } | |
825 | ||
826 | static int | |
827 | loop_release_xfer(struct loop_device *lo) | |
828 | { | |
829 | int err = 0; | |
830 | struct loop_func_table *xfer = lo->lo_encryption; | |
831 | ||
832 | if (xfer) { | |
833 | if (xfer->release) | |
834 | err = xfer->release(lo); | |
835 | lo->transfer = NULL; | |
836 | lo->lo_encryption = NULL; | |
837 | module_put(xfer->owner); | |
838 | } | |
839 | return err; | |
840 | } | |
841 | ||
842 | static int | |
843 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, | |
844 | const struct loop_info64 *i) | |
845 | { | |
846 | int err = 0; | |
847 | ||
848 | if (xfer) { | |
849 | struct module *owner = xfer->owner; | |
850 | ||
851 | if (!try_module_get(owner)) | |
852 | return -EINVAL; | |
853 | if (xfer->init) | |
854 | err = xfer->init(lo, i); | |
855 | if (err) | |
856 | module_put(owner); | |
857 | else | |
858 | lo->lo_encryption = xfer; | |
859 | } | |
860 | return err; | |
861 | } | |
862 | ||
4c823cc3 | 863 | static int loop_clr_fd(struct loop_device *lo) |
1da177e4 LT |
864 | { |
865 | struct file *filp = lo->lo_backing_file; | |
b4e3ca1a | 866 | gfp_t gfp = lo->old_gfp_mask; |
4c823cc3 | 867 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
868 | |
869 | if (lo->lo_state != Lo_bound) | |
870 | return -ENXIO; | |
871 | ||
a1ecac3b DC |
872 | /* |
873 | * If we've explicitly asked to tear down the loop device, | |
874 | * and it has an elevated reference count, set it for auto-teardown when | |
875 | * the last reference goes away. This stops $!~#$@ udev from | |
876 | * preventing teardown because it decided that it needs to run blkid on | |
877 | * the loopback device whenever they appear. xfstests is notorious for | |
878 | * failing tests because blkid via udev races with a losetup | |
879 | * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d | |
880 | * command to fail with EBUSY. | |
881 | */ | |
882 | if (lo->lo_refcnt > 1) { | |
883 | lo->lo_flags |= LO_FLAGS_AUTOCLEAR; | |
884 | mutex_unlock(&lo->lo_ctl_mutex); | |
885 | return 0; | |
886 | } | |
1da177e4 LT |
887 | |
888 | if (filp == NULL) | |
889 | return -EINVAL; | |
890 | ||
891 | spin_lock_irq(&lo->lo_lock); | |
892 | lo->lo_state = Lo_rundown; | |
1da177e4 | 893 | lo->lo_backing_file = NULL; |
05eb0f25 | 894 | spin_unlock_irq(&lo->lo_lock); |
1da177e4 LT |
895 | |
896 | loop_release_xfer(lo); | |
897 | lo->transfer = NULL; | |
898 | lo->ioctl = NULL; | |
899 | lo->lo_device = NULL; | |
900 | lo->lo_encryption = NULL; | |
901 | lo->lo_offset = 0; | |
902 | lo->lo_sizelimit = 0; | |
903 | lo->lo_encrypt_key_size = 0; | |
1da177e4 LT |
904 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
905 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); | |
906 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); | |
c1681bf8 AP |
907 | if (bdev) { |
908 | bdput(bdev); | |
bb214884 | 909 | invalidate_bdev(bdev); |
c1681bf8 | 910 | } |
73285082 | 911 | set_capacity(lo->lo_disk, 0); |
51a0bb0c | 912 | loop_sysfs_exit(lo); |
c3473c63 | 913 | if (bdev) { |
bb214884 | 914 | bd_set_size(bdev, 0); |
c3473c63 DZ |
915 | /* let user-space know about this change */ |
916 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
917 | } | |
1da177e4 LT |
918 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
919 | lo->lo_state = Lo_unbound; | |
1da177e4 LT |
920 | /* This is safe: open() is still holding a reference. */ |
921 | module_put(THIS_MODULE); | |
c2fccc1c JA |
922 | if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) |
923 | ioctl_by_bdev(bdev, BLKRRPART, 0); | |
e03c8dd1 KS |
924 | lo->lo_flags = 0; |
925 | if (!part_shift) | |
926 | lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; | |
f028f3b2 NK |
927 | mutex_unlock(&lo->lo_ctl_mutex); |
928 | /* | |
929 | * Need not hold lo_ctl_mutex to fput backing file. | |
930 | * Calling fput holding lo_ctl_mutex triggers a circular | |
931 | * lock dependency possibility warning as fput can take | |
932 | * bd_mutex which is usually taken before lo_ctl_mutex. | |
933 | */ | |
934 | fput(filp); | |
1da177e4 LT |
935 | return 0; |
936 | } | |
937 | ||
938 | static int | |
939 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) | |
940 | { | |
941 | int err; | |
942 | struct loop_func_table *xfer; | |
e4849737 | 943 | kuid_t uid = current_uid(); |
1da177e4 | 944 | |
b0fafa81 | 945 | if (lo->lo_encrypt_key_size && |
e4849737 | 946 | !uid_eq(lo->lo_key_owner, uid) && |
1da177e4 LT |
947 | !capable(CAP_SYS_ADMIN)) |
948 | return -EPERM; | |
949 | if (lo->lo_state != Lo_bound) | |
950 | return -ENXIO; | |
951 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) | |
952 | return -EINVAL; | |
953 | ||
954 | err = loop_release_xfer(lo); | |
955 | if (err) | |
956 | return err; | |
957 | ||
958 | if (info->lo_encrypt_type) { | |
959 | unsigned int type = info->lo_encrypt_type; | |
960 | ||
961 | if (type >= MAX_LO_CRYPT) | |
962 | return -EINVAL; | |
963 | xfer = xfer_funcs[type]; | |
964 | if (xfer == NULL) | |
965 | return -EINVAL; | |
966 | } else | |
967 | xfer = NULL; | |
968 | ||
969 | err = loop_init_xfer(lo, xfer, info); | |
970 | if (err) | |
971 | return err; | |
972 | ||
973 | if (lo->lo_offset != info->lo_offset || | |
7b0576a3 | 974 | lo->lo_sizelimit != info->lo_sizelimit) |
7035b5df | 975 | if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) |
1da177e4 | 976 | return -EFBIG; |
541c742a | 977 | |
dfaa2ef6 | 978 | loop_config_discard(lo); |
1da177e4 LT |
979 | |
980 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); | |
981 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); | |
982 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; | |
983 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; | |
984 | ||
985 | if (!xfer) | |
986 | xfer = &none_funcs; | |
987 | lo->transfer = xfer->transfer; | |
988 | lo->ioctl = xfer->ioctl; | |
989 | ||
96c58655 DW |
990 | if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != |
991 | (info->lo_flags & LO_FLAGS_AUTOCLEAR)) | |
992 | lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; | |
993 | ||
e03c8dd1 KS |
994 | if ((info->lo_flags & LO_FLAGS_PARTSCAN) && |
995 | !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { | |
996 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
997 | lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; | |
998 | ioctl_by_bdev(lo->lo_device, BLKRRPART, 0); | |
999 | } | |
1000 | ||
1da177e4 LT |
1001 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; |
1002 | lo->lo_init[0] = info->lo_init[0]; | |
1003 | lo->lo_init[1] = info->lo_init[1]; | |
1004 | if (info->lo_encrypt_key_size) { | |
1005 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, | |
1006 | info->lo_encrypt_key_size); | |
b0fafa81 | 1007 | lo->lo_key_owner = uid; |
1da177e4 LT |
1008 | } |
1009 | ||
1010 | return 0; | |
1011 | } | |
1012 | ||
1013 | static int | |
1014 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) | |
1015 | { | |
1016 | struct file *file = lo->lo_backing_file; | |
1017 | struct kstat stat; | |
1018 | int error; | |
1019 | ||
1020 | if (lo->lo_state != Lo_bound) | |
1021 | return -ENXIO; | |
3dadecce | 1022 | error = vfs_getattr(&file->f_path, &stat); |
1da177e4 LT |
1023 | if (error) |
1024 | return error; | |
1025 | memset(info, 0, sizeof(*info)); | |
1026 | info->lo_number = lo->lo_number; | |
1027 | info->lo_device = huge_encode_dev(stat.dev); | |
1028 | info->lo_inode = stat.ino; | |
1029 | info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev); | |
1030 | info->lo_offset = lo->lo_offset; | |
1031 | info->lo_sizelimit = lo->lo_sizelimit; | |
1032 | info->lo_flags = lo->lo_flags; | |
1033 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); | |
1034 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); | |
1035 | info->lo_encrypt_type = | |
1036 | lo->lo_encryption ? lo->lo_encryption->number : 0; | |
1037 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { | |
1038 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; | |
1039 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, | |
1040 | lo->lo_encrypt_key_size); | |
1041 | } | |
1042 | return 0; | |
1043 | } | |
1044 | ||
1045 | static void | |
1046 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) | |
1047 | { | |
1048 | memset(info64, 0, sizeof(*info64)); | |
1049 | info64->lo_number = info->lo_number; | |
1050 | info64->lo_device = info->lo_device; | |
1051 | info64->lo_inode = info->lo_inode; | |
1052 | info64->lo_rdevice = info->lo_rdevice; | |
1053 | info64->lo_offset = info->lo_offset; | |
1054 | info64->lo_sizelimit = 0; | |
1055 | info64->lo_encrypt_type = info->lo_encrypt_type; | |
1056 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; | |
1057 | info64->lo_flags = info->lo_flags; | |
1058 | info64->lo_init[0] = info->lo_init[0]; | |
1059 | info64->lo_init[1] = info->lo_init[1]; | |
1060 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1061 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); | |
1062 | else | |
1063 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); | |
1064 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); | |
1065 | } | |
1066 | ||
1067 | static int | |
1068 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) | |
1069 | { | |
1070 | memset(info, 0, sizeof(*info)); | |
1071 | info->lo_number = info64->lo_number; | |
1072 | info->lo_device = info64->lo_device; | |
1073 | info->lo_inode = info64->lo_inode; | |
1074 | info->lo_rdevice = info64->lo_rdevice; | |
1075 | info->lo_offset = info64->lo_offset; | |
1076 | info->lo_encrypt_type = info64->lo_encrypt_type; | |
1077 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1078 | info->lo_flags = info64->lo_flags; | |
1079 | info->lo_init[0] = info64->lo_init[0]; | |
1080 | info->lo_init[1] = info64->lo_init[1]; | |
1081 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1082 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1083 | else | |
1084 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1085 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1086 | ||
1087 | /* error in case values were truncated */ | |
1088 | if (info->lo_device != info64->lo_device || | |
1089 | info->lo_rdevice != info64->lo_rdevice || | |
1090 | info->lo_inode != info64->lo_inode || | |
1091 | info->lo_offset != info64->lo_offset) | |
1092 | return -EOVERFLOW; | |
1093 | ||
1094 | return 0; | |
1095 | } | |
1096 | ||
1097 | static int | |
1098 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) | |
1099 | { | |
1100 | struct loop_info info; | |
1101 | struct loop_info64 info64; | |
1102 | ||
1103 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) | |
1104 | return -EFAULT; | |
1105 | loop_info64_from_old(&info, &info64); | |
1106 | return loop_set_status(lo, &info64); | |
1107 | } | |
1108 | ||
1109 | static int | |
1110 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) | |
1111 | { | |
1112 | struct loop_info64 info64; | |
1113 | ||
1114 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) | |
1115 | return -EFAULT; | |
1116 | return loop_set_status(lo, &info64); | |
1117 | } | |
1118 | ||
1119 | static int | |
1120 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { | |
1121 | struct loop_info info; | |
1122 | struct loop_info64 info64; | |
1123 | int err = 0; | |
1124 | ||
1125 | if (!arg) | |
1126 | err = -EINVAL; | |
1127 | if (!err) | |
1128 | err = loop_get_status(lo, &info64); | |
1129 | if (!err) | |
1130 | err = loop_info64_to_old(&info64, &info); | |
1131 | if (!err && copy_to_user(arg, &info, sizeof(info))) | |
1132 | err = -EFAULT; | |
1133 | ||
1134 | return err; | |
1135 | } | |
1136 | ||
1137 | static int | |
1138 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { | |
1139 | struct loop_info64 info64; | |
1140 | int err = 0; | |
1141 | ||
1142 | if (!arg) | |
1143 | err = -EINVAL; | |
1144 | if (!err) | |
1145 | err = loop_get_status(lo, &info64); | |
1146 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) | |
1147 | err = -EFAULT; | |
1148 | ||
1149 | return err; | |
1150 | } | |
1151 | ||
53d66608 O |
1152 | static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) |
1153 | { | |
53d66608 | 1154 | if (unlikely(lo->lo_state != Lo_bound)) |
7b0576a3 | 1155 | return -ENXIO; |
53d66608 | 1156 | |
7b0576a3 | 1157 | return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); |
53d66608 O |
1158 | } |
1159 | ||
bb214884 | 1160 | static int lo_ioctl(struct block_device *bdev, fmode_t mode, |
1da177e4 LT |
1161 | unsigned int cmd, unsigned long arg) |
1162 | { | |
bb214884 | 1163 | struct loop_device *lo = bdev->bd_disk->private_data; |
1da177e4 LT |
1164 | int err; |
1165 | ||
f028f3b2 | 1166 | mutex_lock_nested(&lo->lo_ctl_mutex, 1); |
1da177e4 LT |
1167 | switch (cmd) { |
1168 | case LOOP_SET_FD: | |
bb214884 | 1169 | err = loop_set_fd(lo, mode, bdev, arg); |
1da177e4 LT |
1170 | break; |
1171 | case LOOP_CHANGE_FD: | |
bb214884 | 1172 | err = loop_change_fd(lo, bdev, arg); |
1da177e4 LT |
1173 | break; |
1174 | case LOOP_CLR_FD: | |
f028f3b2 | 1175 | /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ |
4c823cc3 | 1176 | err = loop_clr_fd(lo); |
f028f3b2 NK |
1177 | if (!err) |
1178 | goto out_unlocked; | |
1da177e4 LT |
1179 | break; |
1180 | case LOOP_SET_STATUS: | |
7035b5df DM |
1181 | err = -EPERM; |
1182 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1183 | err = loop_set_status_old(lo, | |
1184 | (struct loop_info __user *)arg); | |
1da177e4 LT |
1185 | break; |
1186 | case LOOP_GET_STATUS: | |
1187 | err = loop_get_status_old(lo, (struct loop_info __user *) arg); | |
1188 | break; | |
1189 | case LOOP_SET_STATUS64: | |
7035b5df DM |
1190 | err = -EPERM; |
1191 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1192 | err = loop_set_status64(lo, | |
1193 | (struct loop_info64 __user *) arg); | |
1da177e4 LT |
1194 | break; |
1195 | case LOOP_GET_STATUS64: | |
1196 | err = loop_get_status64(lo, (struct loop_info64 __user *) arg); | |
1197 | break; | |
53d66608 O |
1198 | case LOOP_SET_CAPACITY: |
1199 | err = -EPERM; | |
1200 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1201 | err = loop_set_capacity(lo, bdev); | |
1202 | break; | |
1da177e4 LT |
1203 | default: |
1204 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; | |
1205 | } | |
f85221dd | 1206 | mutex_unlock(&lo->lo_ctl_mutex); |
f028f3b2 NK |
1207 | |
1208 | out_unlocked: | |
1da177e4 LT |
1209 | return err; |
1210 | } | |
1211 | ||
863d5b82 DH |
1212 | #ifdef CONFIG_COMPAT |
1213 | struct compat_loop_info { | |
1214 | compat_int_t lo_number; /* ioctl r/o */ | |
1215 | compat_dev_t lo_device; /* ioctl r/o */ | |
1216 | compat_ulong_t lo_inode; /* ioctl r/o */ | |
1217 | compat_dev_t lo_rdevice; /* ioctl r/o */ | |
1218 | compat_int_t lo_offset; | |
1219 | compat_int_t lo_encrypt_type; | |
1220 | compat_int_t lo_encrypt_key_size; /* ioctl w/o */ | |
1221 | compat_int_t lo_flags; /* ioctl r/o */ | |
1222 | char lo_name[LO_NAME_SIZE]; | |
1223 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ | |
1224 | compat_ulong_t lo_init[2]; | |
1225 | char reserved[4]; | |
1226 | }; | |
1227 | ||
1228 | /* | |
1229 | * Transfer 32-bit compatibility structure in userspace to 64-bit loop info | |
1230 | * - noinlined to reduce stack space usage in main part of driver | |
1231 | */ | |
1232 | static noinline int | |
ba674cfc | 1233 | loop_info64_from_compat(const struct compat_loop_info __user *arg, |
863d5b82 DH |
1234 | struct loop_info64 *info64) |
1235 | { | |
1236 | struct compat_loop_info info; | |
1237 | ||
1238 | if (copy_from_user(&info, arg, sizeof(info))) | |
1239 | return -EFAULT; | |
1240 | ||
1241 | memset(info64, 0, sizeof(*info64)); | |
1242 | info64->lo_number = info.lo_number; | |
1243 | info64->lo_device = info.lo_device; | |
1244 | info64->lo_inode = info.lo_inode; | |
1245 | info64->lo_rdevice = info.lo_rdevice; | |
1246 | info64->lo_offset = info.lo_offset; | |
1247 | info64->lo_sizelimit = 0; | |
1248 | info64->lo_encrypt_type = info.lo_encrypt_type; | |
1249 | info64->lo_encrypt_key_size = info.lo_encrypt_key_size; | |
1250 | info64->lo_flags = info.lo_flags; | |
1251 | info64->lo_init[0] = info.lo_init[0]; | |
1252 | info64->lo_init[1] = info.lo_init[1]; | |
1253 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1254 | memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); | |
1255 | else | |
1256 | memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); | |
1257 | memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); | |
1258 | return 0; | |
1259 | } | |
1260 | ||
1261 | /* | |
1262 | * Transfer 64-bit loop info to 32-bit compatibility structure in userspace | |
1263 | * - noinlined to reduce stack space usage in main part of driver | |
1264 | */ | |
1265 | static noinline int | |
1266 | loop_info64_to_compat(const struct loop_info64 *info64, | |
1267 | struct compat_loop_info __user *arg) | |
1268 | { | |
1269 | struct compat_loop_info info; | |
1270 | ||
1271 | memset(&info, 0, sizeof(info)); | |
1272 | info.lo_number = info64->lo_number; | |
1273 | info.lo_device = info64->lo_device; | |
1274 | info.lo_inode = info64->lo_inode; | |
1275 | info.lo_rdevice = info64->lo_rdevice; | |
1276 | info.lo_offset = info64->lo_offset; | |
1277 | info.lo_encrypt_type = info64->lo_encrypt_type; | |
1278 | info.lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1279 | info.lo_flags = info64->lo_flags; | |
1280 | info.lo_init[0] = info64->lo_init[0]; | |
1281 | info.lo_init[1] = info64->lo_init[1]; | |
1282 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1283 | memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1284 | else | |
1285 | memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1286 | memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1287 | ||
1288 | /* error in case values were truncated */ | |
1289 | if (info.lo_device != info64->lo_device || | |
1290 | info.lo_rdevice != info64->lo_rdevice || | |
1291 | info.lo_inode != info64->lo_inode || | |
1292 | info.lo_offset != info64->lo_offset || | |
1293 | info.lo_init[0] != info64->lo_init[0] || | |
1294 | info.lo_init[1] != info64->lo_init[1]) | |
1295 | return -EOVERFLOW; | |
1296 | ||
1297 | if (copy_to_user(arg, &info, sizeof(info))) | |
1298 | return -EFAULT; | |
1299 | return 0; | |
1300 | } | |
1301 | ||
1302 | static int | |
1303 | loop_set_status_compat(struct loop_device *lo, | |
1304 | const struct compat_loop_info __user *arg) | |
1305 | { | |
1306 | struct loop_info64 info64; | |
1307 | int ret; | |
1308 | ||
1309 | ret = loop_info64_from_compat(arg, &info64); | |
1310 | if (ret < 0) | |
1311 | return ret; | |
1312 | return loop_set_status(lo, &info64); | |
1313 | } | |
1314 | ||
1315 | static int | |
1316 | loop_get_status_compat(struct loop_device *lo, | |
1317 | struct compat_loop_info __user *arg) | |
1318 | { | |
1319 | struct loop_info64 info64; | |
1320 | int err = 0; | |
1321 | ||
1322 | if (!arg) | |
1323 | err = -EINVAL; | |
1324 | if (!err) | |
1325 | err = loop_get_status(lo, &info64); | |
1326 | if (!err) | |
1327 | err = loop_info64_to_compat(&info64, arg); | |
1328 | return err; | |
1329 | } | |
1330 | ||
bb214884 AV |
1331 | static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
1332 | unsigned int cmd, unsigned long arg) | |
863d5b82 | 1333 | { |
bb214884 | 1334 | struct loop_device *lo = bdev->bd_disk->private_data; |
863d5b82 DH |
1335 | int err; |
1336 | ||
863d5b82 DH |
1337 | switch(cmd) { |
1338 | case LOOP_SET_STATUS: | |
1339 | mutex_lock(&lo->lo_ctl_mutex); | |
1340 | err = loop_set_status_compat( | |
1341 | lo, (const struct compat_loop_info __user *) arg); | |
1342 | mutex_unlock(&lo->lo_ctl_mutex); | |
1343 | break; | |
1344 | case LOOP_GET_STATUS: | |
1345 | mutex_lock(&lo->lo_ctl_mutex); | |
1346 | err = loop_get_status_compat( | |
1347 | lo, (struct compat_loop_info __user *) arg); | |
1348 | mutex_unlock(&lo->lo_ctl_mutex); | |
1349 | break; | |
53d66608 | 1350 | case LOOP_SET_CAPACITY: |
863d5b82 DH |
1351 | case LOOP_CLR_FD: |
1352 | case LOOP_GET_STATUS64: | |
1353 | case LOOP_SET_STATUS64: | |
1354 | arg = (unsigned long) compat_ptr(arg); | |
1355 | case LOOP_SET_FD: | |
1356 | case LOOP_CHANGE_FD: | |
bb214884 | 1357 | err = lo_ioctl(bdev, mode, cmd, arg); |
863d5b82 DH |
1358 | break; |
1359 | default: | |
1360 | err = -ENOIOCTLCMD; | |
1361 | break; | |
1362 | } | |
863d5b82 DH |
1363 | return err; |
1364 | } | |
1365 | #endif | |
1366 | ||
bb214884 | 1367 | static int lo_open(struct block_device *bdev, fmode_t mode) |
1da177e4 | 1368 | { |
770fe30a KS |
1369 | struct loop_device *lo; |
1370 | int err = 0; | |
1371 | ||
1372 | mutex_lock(&loop_index_mutex); | |
1373 | lo = bdev->bd_disk->private_data; | |
1374 | if (!lo) { | |
1375 | err = -ENXIO; | |
1376 | goto out; | |
1377 | } | |
1da177e4 | 1378 | |
f85221dd | 1379 | mutex_lock(&lo->lo_ctl_mutex); |
1da177e4 | 1380 | lo->lo_refcnt++; |
f85221dd | 1381 | mutex_unlock(&lo->lo_ctl_mutex); |
770fe30a KS |
1382 | out: |
1383 | mutex_unlock(&loop_index_mutex); | |
1384 | return err; | |
1da177e4 LT |
1385 | } |
1386 | ||
db2a144b | 1387 | static void lo_release(struct gendisk *disk, fmode_t mode) |
1da177e4 | 1388 | { |
bb214884 | 1389 | struct loop_device *lo = disk->private_data; |
ffcd7dca | 1390 | int err; |
1da177e4 | 1391 | |
f85221dd | 1392 | mutex_lock(&lo->lo_ctl_mutex); |
96c58655 | 1393 | |
14f27939 MB |
1394 | if (--lo->lo_refcnt) |
1395 | goto out; | |
1396 | ||
1397 | if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { | |
1398 | /* | |
1399 | * In autoclear mode, stop the loop thread | |
1400 | * and remove configuration after last close. | |
1401 | */ | |
4c823cc3 | 1402 | err = loop_clr_fd(lo); |
ffcd7dca | 1403 | if (!err) |
db2a144b | 1404 | return; |
14f27939 MB |
1405 | } else { |
1406 | /* | |
1407 | * Otherwise keep thread (if running) and config, | |
1408 | * but flush possible ongoing bios in thread. | |
1409 | */ | |
1410 | loop_flush(lo); | |
1411 | } | |
96c58655 | 1412 | |
14f27939 | 1413 | out: |
f85221dd | 1414 | mutex_unlock(&lo->lo_ctl_mutex); |
1da177e4 LT |
1415 | } |
1416 | ||
83d5cde4 | 1417 | static const struct block_device_operations lo_fops = { |
1da177e4 | 1418 | .owner = THIS_MODULE, |
bb214884 AV |
1419 | .open = lo_open, |
1420 | .release = lo_release, | |
1421 | .ioctl = lo_ioctl, | |
863d5b82 | 1422 | #ifdef CONFIG_COMPAT |
bb214884 | 1423 | .compat_ioctl = lo_compat_ioctl, |
863d5b82 | 1424 | #endif |
1da177e4 LT |
1425 | }; |
1426 | ||
1427 | /* | |
1428 | * And now the modules code and kernel interface. | |
1429 | */ | |
73285082 | 1430 | static int max_loop; |
ac04fee0 | 1431 | module_param(max_loop, int, S_IRUGO); |
a47653fc | 1432 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
ac04fee0 | 1433 | module_param(max_part, int, S_IRUGO); |
476a4813 | 1434 | MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
1da177e4 LT |
1435 | MODULE_LICENSE("GPL"); |
1436 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); | |
1437 | ||
1438 | int loop_register_transfer(struct loop_func_table *funcs) | |
1439 | { | |
1440 | unsigned int n = funcs->number; | |
1441 | ||
1442 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) | |
1443 | return -EINVAL; | |
1444 | xfer_funcs[n] = funcs; | |
1445 | return 0; | |
1446 | } | |
1447 | ||
34dd82af KS |
1448 | static int unregister_transfer_cb(int id, void *ptr, void *data) |
1449 | { | |
1450 | struct loop_device *lo = ptr; | |
1451 | struct loop_func_table *xfer = data; | |
1452 | ||
1453 | mutex_lock(&lo->lo_ctl_mutex); | |
1454 | if (lo->lo_encryption == xfer) | |
1455 | loop_release_xfer(lo); | |
1456 | mutex_unlock(&lo->lo_ctl_mutex); | |
1457 | return 0; | |
1458 | } | |
1459 | ||
1da177e4 LT |
1460 | int loop_unregister_transfer(int number) |
1461 | { | |
1462 | unsigned int n = number; | |
1da177e4 LT |
1463 | struct loop_func_table *xfer; |
1464 | ||
1465 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) | |
1466 | return -EINVAL; | |
1467 | ||
1468 | xfer_funcs[n] = NULL; | |
34dd82af | 1469 | idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer); |
1da177e4 LT |
1470 | return 0; |
1471 | } | |
1472 | ||
1473 | EXPORT_SYMBOL(loop_register_transfer); | |
1474 | EXPORT_SYMBOL(loop_unregister_transfer); | |
1475 | ||
b5dd2f60 ML |
1476 | static int loop_queue_rq(struct blk_mq_hw_ctx *hctx, |
1477 | const struct blk_mq_queue_data *bd) | |
1478 | { | |
1479 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); | |
1480 | ||
1481 | blk_mq_start_request(bd->rq); | |
1482 | ||
1483 | if (cmd->rq->cmd_flags & REQ_WRITE) { | |
1484 | struct loop_device *lo = cmd->rq->q->queuedata; | |
1485 | bool need_sched = true; | |
1486 | ||
1487 | spin_lock_irq(&lo->lo_lock); | |
1488 | if (lo->write_started) | |
1489 | need_sched = false; | |
1490 | else | |
1491 | lo->write_started = true; | |
1492 | list_add_tail(&cmd->list, &lo->write_cmd_head); | |
1493 | spin_unlock_irq(&lo->lo_lock); | |
1494 | ||
1495 | if (need_sched) | |
1496 | queue_work(loop_wq, &lo->write_work); | |
1497 | } else { | |
1498 | queue_work(loop_wq, &cmd->read_work); | |
1499 | } | |
1500 | ||
1501 | return BLK_MQ_RQ_QUEUE_OK; | |
1502 | } | |
1503 | ||
1504 | static void loop_handle_cmd(struct loop_cmd *cmd) | |
1505 | { | |
1506 | const bool write = cmd->rq->cmd_flags & REQ_WRITE; | |
1507 | struct loop_device *lo = cmd->rq->q->queuedata; | |
1508 | int ret = -EIO; | |
b5dd2f60 ML |
1509 | |
1510 | if (lo->lo_state != Lo_bound) | |
1511 | goto failed; | |
1512 | ||
1513 | if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) | |
1514 | goto failed; | |
1515 | ||
30112013 | 1516 | ret = do_req_filebacked(lo, cmd->rq); |
b5dd2f60 ML |
1517 | |
1518 | failed: | |
1519 | if (ret) | |
1520 | cmd->rq->errors = -EIO; | |
1521 | blk_mq_complete_request(cmd->rq); | |
1522 | } | |
1523 | ||
1524 | static void loop_queue_write_work(struct work_struct *work) | |
1525 | { | |
1526 | struct loop_device *lo = | |
1527 | container_of(work, struct loop_device, write_work); | |
1528 | LIST_HEAD(cmd_list); | |
1529 | ||
1530 | spin_lock_irq(&lo->lo_lock); | |
1531 | repeat: | |
1532 | list_splice_init(&lo->write_cmd_head, &cmd_list); | |
1533 | spin_unlock_irq(&lo->lo_lock); | |
1534 | ||
1535 | while (!list_empty(&cmd_list)) { | |
1536 | struct loop_cmd *cmd = list_first_entry(&cmd_list, | |
1537 | struct loop_cmd, list); | |
1538 | list_del_init(&cmd->list); | |
1539 | loop_handle_cmd(cmd); | |
1540 | } | |
1541 | ||
1542 | spin_lock_irq(&lo->lo_lock); | |
1543 | if (!list_empty(&lo->write_cmd_head)) | |
1544 | goto repeat; | |
1545 | lo->write_started = false; | |
1546 | spin_unlock_irq(&lo->lo_lock); | |
1547 | } | |
1548 | ||
1549 | static void loop_queue_read_work(struct work_struct *work) | |
1550 | { | |
1551 | struct loop_cmd *cmd = | |
1552 | container_of(work, struct loop_cmd, read_work); | |
1553 | ||
1554 | loop_handle_cmd(cmd); | |
1555 | } | |
1556 | ||
1557 | static int loop_init_request(void *data, struct request *rq, | |
1558 | unsigned int hctx_idx, unsigned int request_idx, | |
1559 | unsigned int numa_node) | |
1560 | { | |
1561 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
1562 | ||
1563 | cmd->rq = rq; | |
1564 | INIT_WORK(&cmd->read_work, loop_queue_read_work); | |
1565 | ||
1566 | return 0; | |
1567 | } | |
1568 | ||
1569 | static struct blk_mq_ops loop_mq_ops = { | |
1570 | .queue_rq = loop_queue_rq, | |
1571 | .map_queue = blk_mq_map_queue, | |
1572 | .init_request = loop_init_request, | |
1573 | }; | |
1574 | ||
34dd82af | 1575 | static int loop_add(struct loop_device **l, int i) |
73285082 KC |
1576 | { |
1577 | struct loop_device *lo; | |
1578 | struct gendisk *disk; | |
34dd82af | 1579 | int err; |
73285082 | 1580 | |
68d740d7 | 1581 | err = -ENOMEM; |
73285082 | 1582 | lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
68d740d7 | 1583 | if (!lo) |
73285082 | 1584 | goto out; |
34dd82af | 1585 | |
ef7e7c82 MP |
1586 | lo->lo_state = Lo_unbound; |
1587 | ||
c718aa65 | 1588 | /* allocate id, if @id >= 0, we're requesting that specific id */ |
34dd82af | 1589 | if (i >= 0) { |
c718aa65 TH |
1590 | err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL); |
1591 | if (err == -ENOSPC) | |
34dd82af | 1592 | err = -EEXIST; |
34dd82af | 1593 | } else { |
c718aa65 | 1594 | err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL); |
34dd82af KS |
1595 | } |
1596 | if (err < 0) | |
1597 | goto out_free_dev; | |
c718aa65 | 1598 | i = err; |
73285082 | 1599 | |
183cfb57 | 1600 | err = -ENOMEM; |
b5dd2f60 ML |
1601 | lo->tag_set.ops = &loop_mq_ops; |
1602 | lo->tag_set.nr_hw_queues = 1; | |
1603 | lo->tag_set.queue_depth = 128; | |
1604 | lo->tag_set.numa_node = NUMA_NO_NODE; | |
1605 | lo->tag_set.cmd_size = sizeof(struct loop_cmd); | |
1606 | lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; | |
1607 | lo->tag_set.driver_data = lo; | |
1608 | ||
1609 | err = blk_mq_alloc_tag_set(&lo->tag_set); | |
1610 | if (err) | |
3ec981e3 | 1611 | goto out_free_idr; |
73285082 | 1612 | |
b5dd2f60 ML |
1613 | lo->lo_queue = blk_mq_init_queue(&lo->tag_set); |
1614 | if (IS_ERR_OR_NULL(lo->lo_queue)) { | |
1615 | err = PTR_ERR(lo->lo_queue); | |
1616 | goto out_cleanup_tags; | |
1617 | } | |
ef7e7c82 MP |
1618 | lo->lo_queue->queuedata = lo; |
1619 | ||
b5dd2f60 ML |
1620 | INIT_LIST_HEAD(&lo->write_cmd_head); |
1621 | INIT_WORK(&lo->write_work, loop_queue_write_work); | |
1622 | ||
476a4813 | 1623 | disk = lo->lo_disk = alloc_disk(1 << part_shift); |
73285082 KC |
1624 | if (!disk) |
1625 | goto out_free_queue; | |
1626 | ||
e03c8dd1 KS |
1627 | /* |
1628 | * Disable partition scanning by default. The in-kernel partition | |
1629 | * scanning can be requested individually per-device during its | |
1630 | * setup. Userspace can always add and remove partitions from all | |
1631 | * devices. The needed partition minors are allocated from the | |
1632 | * extended minor space, the main loop device numbers will continue | |
1633 | * to match the loop minors, regardless of the number of partitions | |
1634 | * used. | |
1635 | * | |
1636 | * If max_part is given, partition scanning is globally enabled for | |
1637 | * all loop devices. The minors for the main loop devices will be | |
1638 | * multiples of max_part. | |
1639 | * | |
1640 | * Note: Global-for-all-devices, set-only-at-init, read-only module | |
1641 | * parameteters like 'max_loop' and 'max_part' make things needlessly | |
1642 | * complicated, are too static, inflexible and may surprise | |
1643 | * userspace tools. Parameters like this in general should be avoided. | |
1644 | */ | |
1645 | if (!part_shift) | |
1646 | disk->flags |= GENHD_FL_NO_PART_SCAN; | |
1647 | disk->flags |= GENHD_FL_EXT_DEVT; | |
73285082 KC |
1648 | mutex_init(&lo->lo_ctl_mutex); |
1649 | lo->lo_number = i; | |
73285082 KC |
1650 | spin_lock_init(&lo->lo_lock); |
1651 | disk->major = LOOP_MAJOR; | |
476a4813 | 1652 | disk->first_minor = i << part_shift; |
73285082 KC |
1653 | disk->fops = &lo_fops; |
1654 | disk->private_data = lo; | |
1655 | disk->queue = lo->lo_queue; | |
1656 | sprintf(disk->disk_name, "loop%d", i); | |
34dd82af KS |
1657 | add_disk(disk); |
1658 | *l = lo; | |
1659 | return lo->lo_number; | |
73285082 KC |
1660 | |
1661 | out_free_queue: | |
1662 | blk_cleanup_queue(lo->lo_queue); | |
b5dd2f60 ML |
1663 | out_cleanup_tags: |
1664 | blk_mq_free_tag_set(&lo->tag_set); | |
3ec981e3 MP |
1665 | out_free_idr: |
1666 | idr_remove(&loop_index_idr, i); | |
73285082 KC |
1667 | out_free_dev: |
1668 | kfree(lo); | |
1669 | out: | |
34dd82af | 1670 | return err; |
73285082 KC |
1671 | } |
1672 | ||
34dd82af | 1673 | static void loop_remove(struct loop_device *lo) |
1da177e4 | 1674 | { |
34dd82af | 1675 | del_gendisk(lo->lo_disk); |
73285082 | 1676 | blk_cleanup_queue(lo->lo_queue); |
b5dd2f60 | 1677 | blk_mq_free_tag_set(&lo->tag_set); |
73285082 | 1678 | put_disk(lo->lo_disk); |
73285082 KC |
1679 | kfree(lo); |
1680 | } | |
1da177e4 | 1681 | |
770fe30a KS |
1682 | static int find_free_cb(int id, void *ptr, void *data) |
1683 | { | |
1684 | struct loop_device *lo = ptr; | |
1685 | struct loop_device **l = data; | |
1686 | ||
1687 | if (lo->lo_state == Lo_unbound) { | |
1688 | *l = lo; | |
1689 | return 1; | |
1690 | } | |
1691 | return 0; | |
1692 | } | |
1693 | ||
34dd82af | 1694 | static int loop_lookup(struct loop_device **l, int i) |
a47653fc KC |
1695 | { |
1696 | struct loop_device *lo; | |
34dd82af | 1697 | int ret = -ENODEV; |
a47653fc | 1698 | |
770fe30a KS |
1699 | if (i < 0) { |
1700 | int err; | |
1701 | ||
1702 | err = idr_for_each(&loop_index_idr, &find_free_cb, &lo); | |
1703 | if (err == 1) { | |
1704 | *l = lo; | |
1705 | ret = lo->lo_number; | |
1706 | } | |
1707 | goto out; | |
a47653fc KC |
1708 | } |
1709 | ||
770fe30a | 1710 | /* lookup and return a specific i */ |
34dd82af | 1711 | lo = idr_find(&loop_index_idr, i); |
a47653fc | 1712 | if (lo) { |
34dd82af KS |
1713 | *l = lo; |
1714 | ret = lo->lo_number; | |
a47653fc | 1715 | } |
770fe30a | 1716 | out: |
34dd82af | 1717 | return ret; |
a47653fc KC |
1718 | } |
1719 | ||
73285082 KC |
1720 | static struct kobject *loop_probe(dev_t dev, int *part, void *data) |
1721 | { | |
705962cc | 1722 | struct loop_device *lo; |
07002e99 | 1723 | struct kobject *kobj; |
34dd82af | 1724 | int err; |
73285082 | 1725 | |
34dd82af KS |
1726 | mutex_lock(&loop_index_mutex); |
1727 | err = loop_lookup(&lo, MINOR(dev) >> part_shift); | |
1728 | if (err < 0) | |
1729 | err = loop_add(&lo, MINOR(dev) >> part_shift); | |
1730 | if (err < 0) | |
a207f593 | 1731 | kobj = NULL; |
34dd82af KS |
1732 | else |
1733 | kobj = get_disk(lo->lo_disk); | |
1734 | mutex_unlock(&loop_index_mutex); | |
73285082 KC |
1735 | |
1736 | *part = 0; | |
07002e99 | 1737 | return kobj; |
73285082 KC |
1738 | } |
1739 | ||
770fe30a KS |
1740 | static long loop_control_ioctl(struct file *file, unsigned int cmd, |
1741 | unsigned long parm) | |
1742 | { | |
1743 | struct loop_device *lo; | |
1744 | int ret = -ENOSYS; | |
1745 | ||
1746 | mutex_lock(&loop_index_mutex); | |
1747 | switch (cmd) { | |
1748 | case LOOP_CTL_ADD: | |
1749 | ret = loop_lookup(&lo, parm); | |
1750 | if (ret >= 0) { | |
1751 | ret = -EEXIST; | |
1752 | break; | |
1753 | } | |
1754 | ret = loop_add(&lo, parm); | |
1755 | break; | |
1756 | case LOOP_CTL_REMOVE: | |
1757 | ret = loop_lookup(&lo, parm); | |
1758 | if (ret < 0) | |
1759 | break; | |
1760 | mutex_lock(&lo->lo_ctl_mutex); | |
1761 | if (lo->lo_state != Lo_unbound) { | |
1762 | ret = -EBUSY; | |
1763 | mutex_unlock(&lo->lo_ctl_mutex); | |
1764 | break; | |
1765 | } | |
1766 | if (lo->lo_refcnt > 0) { | |
1767 | ret = -EBUSY; | |
1768 | mutex_unlock(&lo->lo_ctl_mutex); | |
1769 | break; | |
1770 | } | |
1771 | lo->lo_disk->private_data = NULL; | |
1772 | mutex_unlock(&lo->lo_ctl_mutex); | |
1773 | idr_remove(&loop_index_idr, lo->lo_number); | |
1774 | loop_remove(lo); | |
1775 | break; | |
1776 | case LOOP_CTL_GET_FREE: | |
1777 | ret = loop_lookup(&lo, -1); | |
1778 | if (ret >= 0) | |
1779 | break; | |
1780 | ret = loop_add(&lo, -1); | |
1781 | } | |
1782 | mutex_unlock(&loop_index_mutex); | |
1783 | ||
1784 | return ret; | |
1785 | } | |
1786 | ||
1787 | static const struct file_operations loop_ctl_fops = { | |
1788 | .open = nonseekable_open, | |
1789 | .unlocked_ioctl = loop_control_ioctl, | |
1790 | .compat_ioctl = loop_control_ioctl, | |
1791 | .owner = THIS_MODULE, | |
1792 | .llseek = noop_llseek, | |
1793 | }; | |
1794 | ||
1795 | static struct miscdevice loop_misc = { | |
1796 | .minor = LOOP_CTRL_MINOR, | |
1797 | .name = "loop-control", | |
1798 | .fops = &loop_ctl_fops, | |
1799 | }; | |
1800 | ||
1801 | MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR); | |
1802 | MODULE_ALIAS("devname:loop-control"); | |
1803 | ||
73285082 KC |
1804 | static int __init loop_init(void) |
1805 | { | |
a47653fc KC |
1806 | int i, nr; |
1807 | unsigned long range; | |
34dd82af | 1808 | struct loop_device *lo; |
770fe30a | 1809 | int err; |
a47653fc | 1810 | |
770fe30a KS |
1811 | err = misc_register(&loop_misc); |
1812 | if (err < 0) | |
1813 | return err; | |
476a4813 LV |
1814 | |
1815 | part_shift = 0; | |
ac04fee0 | 1816 | if (max_part > 0) { |
476a4813 LV |
1817 | part_shift = fls(max_part); |
1818 | ||
ac04fee0 NK |
1819 | /* |
1820 | * Adjust max_part according to part_shift as it is exported | |
1821 | * to user space so that user can decide correct minor number | |
1822 | * if [s]he want to create more devices. | |
1823 | * | |
1824 | * Note that -1 is required because partition 0 is reserved | |
1825 | * for the whole disk. | |
1826 | */ | |
1827 | max_part = (1UL << part_shift) - 1; | |
1828 | } | |
1829 | ||
b1a66504 GC |
1830 | if ((1UL << part_shift) > DISK_MAX_PARTS) { |
1831 | err = -EINVAL; | |
1832 | goto misc_out; | |
1833 | } | |
78f4bb36 | 1834 | |
b1a66504 GC |
1835 | if (max_loop > 1UL << (MINORBITS - part_shift)) { |
1836 | err = -EINVAL; | |
1837 | goto misc_out; | |
1838 | } | |
1da177e4 | 1839 | |
d134b00b KS |
1840 | /* |
1841 | * If max_loop is specified, create that many devices upfront. | |
1842 | * This also becomes a hard limit. If max_loop is not specified, | |
1843 | * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module | |
1844 | * init time. Loop devices can be requested on-demand with the | |
1845 | * /dev/loop-control interface, or be instantiated by accessing | |
1846 | * a 'dead' device node. | |
1847 | */ | |
73285082 | 1848 | if (max_loop) { |
a47653fc | 1849 | nr = max_loop; |
a1c15c59 | 1850 | range = max_loop << part_shift; |
a47653fc | 1851 | } else { |
d134b00b | 1852 | nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; |
a1c15c59 | 1853 | range = 1UL << MINORBITS; |
a47653fc KC |
1854 | } |
1855 | ||
b1a66504 GC |
1856 | if (register_blkdev(LOOP_MAJOR, "loop")) { |
1857 | err = -EIO; | |
1858 | goto misc_out; | |
1859 | } | |
1da177e4 | 1860 | |
b5dd2f60 ML |
1861 | loop_wq = alloc_workqueue("kloopd", |
1862 | WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0); | |
1863 | if (!loop_wq) { | |
1864 | err = -ENOMEM; | |
1865 | goto misc_out; | |
1866 | } | |
1867 | ||
a47653fc KC |
1868 | blk_register_region(MKDEV(LOOP_MAJOR, 0), range, |
1869 | THIS_MODULE, loop_probe, NULL, NULL); | |
1870 | ||
d134b00b | 1871 | /* pre-create number of devices given by config or max_loop */ |
34dd82af KS |
1872 | mutex_lock(&loop_index_mutex); |
1873 | for (i = 0; i < nr; i++) | |
1874 | loop_add(&lo, i); | |
1875 | mutex_unlock(&loop_index_mutex); | |
1876 | ||
73285082 | 1877 | printk(KERN_INFO "loop: module loaded\n"); |
1da177e4 | 1878 | return 0; |
b1a66504 GC |
1879 | |
1880 | misc_out: | |
1881 | misc_deregister(&loop_misc); | |
1882 | return err; | |
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 | 1899 | idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); |
34dd82af | 1900 | idr_destroy(&loop_index_idr); |
73285082 | 1901 | |
a47653fc | 1902 | blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); |
00d59405 | 1903 | unregister_blkdev(LOOP_MAJOR, "loop"); |
770fe30a | 1904 | |
b5dd2f60 ML |
1905 | destroy_workqueue(loop_wq); |
1906 | ||
770fe30a | 1907 | misc_deregister(&loop_misc); |
1da177e4 LT |
1908 | } |
1909 | ||
1910 | module_init(loop_init); | |
1911 | module_exit(loop_exit); | |
1912 | ||
1913 | #ifndef MODULE | |
1914 | static int __init max_loop_setup(char *str) | |
1915 | { | |
1916 | max_loop = simple_strtol(str, NULL, 0); | |
1917 | return 1; | |
1918 | } | |
1919 | ||
1920 | __setup("max_loop=", max_loop_setup); | |
1921 | #endif |