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> |
283e7e5d | 78 | #include <linux/uio.h> |
d9a08a9e | 79 | #include <linux/ioprio.h> |
db6638d7 | 80 | #include <linux/blk-cgroup.h> |
d9a08a9e | 81 | |
83a87611 | 82 | #include "loop.h" |
1da177e4 | 83 | |
7c0f6ba6 | 84 | #include <linux/uaccess.h> |
1da177e4 | 85 | |
34dd82af | 86 | static DEFINE_IDR(loop_index_idr); |
310ca162 | 87 | static DEFINE_MUTEX(loop_ctl_mutex); |
1da177e4 | 88 | |
476a4813 LV |
89 | static int max_part; |
90 | static int part_shift; | |
91 | ||
1da177e4 LT |
92 | static int transfer_xor(struct loop_device *lo, int cmd, |
93 | struct page *raw_page, unsigned raw_off, | |
94 | struct page *loop_page, unsigned loop_off, | |
95 | int size, sector_t real_block) | |
96 | { | |
cfd8005c CW |
97 | char *raw_buf = kmap_atomic(raw_page) + raw_off; |
98 | char *loop_buf = kmap_atomic(loop_page) + loop_off; | |
1da177e4 LT |
99 | char *in, *out, *key; |
100 | int i, keysize; | |
101 | ||
102 | if (cmd == READ) { | |
103 | in = raw_buf; | |
104 | out = loop_buf; | |
105 | } else { | |
106 | in = loop_buf; | |
107 | out = raw_buf; | |
108 | } | |
109 | ||
110 | key = lo->lo_encrypt_key; | |
111 | keysize = lo->lo_encrypt_key_size; | |
112 | for (i = 0; i < size; i++) | |
113 | *out++ = *in++ ^ key[(i & 511) % keysize]; | |
114 | ||
cfd8005c CW |
115 | kunmap_atomic(loop_buf); |
116 | kunmap_atomic(raw_buf); | |
1da177e4 LT |
117 | cond_resched(); |
118 | return 0; | |
119 | } | |
120 | ||
121 | static int xor_init(struct loop_device *lo, const struct loop_info64 *info) | |
122 | { | |
123 | if (unlikely(info->lo_encrypt_key_size <= 0)) | |
124 | return -EINVAL; | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static struct loop_func_table none_funcs = { | |
129 | .number = LO_CRYPT_NONE, | |
aa4d8616 | 130 | }; |
1da177e4 LT |
131 | |
132 | static struct loop_func_table xor_funcs = { | |
133 | .number = LO_CRYPT_XOR, | |
134 | .transfer = transfer_xor, | |
135 | .init = xor_init | |
aa4d8616 | 136 | }; |
1da177e4 LT |
137 | |
138 | /* xfer_funcs[0] is special - its release function is never called */ | |
139 | static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { | |
140 | &none_funcs, | |
141 | &xor_funcs | |
142 | }; | |
143 | ||
7035b5df | 144 | static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) |
1da177e4 | 145 | { |
b7a1da69 | 146 | loff_t loopsize; |
1da177e4 LT |
147 | |
148 | /* Compute loopsize in bytes */ | |
b7a1da69 GC |
149 | loopsize = i_size_read(file->f_mapping->host); |
150 | if (offset > 0) | |
151 | loopsize -= offset; | |
152 | /* offset is beyond i_size, weird but possible */ | |
7035b5df DM |
153 | if (loopsize < 0) |
154 | return 0; | |
1da177e4 | 155 | |
7035b5df DM |
156 | if (sizelimit > 0 && sizelimit < loopsize) |
157 | loopsize = sizelimit; | |
1da177e4 LT |
158 | /* |
159 | * Unfortunately, if we want to do I/O on the device, | |
160 | * the number of 512-byte sectors has to fit into a sector_t. | |
161 | */ | |
162 | return loopsize >> 9; | |
163 | } | |
164 | ||
7035b5df DM |
165 | static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
166 | { | |
167 | return get_size(lo->lo_offset, lo->lo_sizelimit, file); | |
168 | } | |
169 | ||
2e5ab5f3 ML |
170 | static void __loop_update_dio(struct loop_device *lo, bool dio) |
171 | { | |
172 | struct file *file = lo->lo_backing_file; | |
173 | struct address_space *mapping = file->f_mapping; | |
174 | struct inode *inode = mapping->host; | |
175 | unsigned short sb_bsize = 0; | |
176 | unsigned dio_align = 0; | |
177 | bool use_dio; | |
178 | ||
179 | if (inode->i_sb->s_bdev) { | |
180 | sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev); | |
181 | dio_align = sb_bsize - 1; | |
182 | } | |
183 | ||
184 | /* | |
185 | * We support direct I/O only if lo_offset is aligned with the | |
186 | * logical I/O size of backing device, and the logical block | |
187 | * size of loop is bigger than the backing device's and the loop | |
188 | * needn't transform transfer. | |
189 | * | |
190 | * TODO: the above condition may be loosed in the future, and | |
191 | * direct I/O may be switched runtime at that time because most | |
89d790ab | 192 | * of requests in sane applications should be PAGE_SIZE aligned |
2e5ab5f3 ML |
193 | */ |
194 | if (dio) { | |
195 | if (queue_logical_block_size(lo->lo_queue) >= sb_bsize && | |
196 | !(lo->lo_offset & dio_align) && | |
197 | mapping->a_ops->direct_IO && | |
198 | !lo->transfer) | |
199 | use_dio = true; | |
200 | else | |
201 | use_dio = false; | |
202 | } else { | |
203 | use_dio = false; | |
204 | } | |
205 | ||
206 | if (lo->use_dio == use_dio) | |
207 | return; | |
208 | ||
209 | /* flush dirty pages before changing direct IO */ | |
210 | vfs_fsync(file, 0); | |
211 | ||
212 | /* | |
213 | * The flag of LO_FLAGS_DIRECT_IO is handled similarly with | |
214 | * LO_FLAGS_READ_ONLY, both are set from kernel, and losetup | |
215 | * will get updated by ioctl(LOOP_GET_STATUS) | |
216 | */ | |
0fbcf579 MC |
217 | if (lo->lo_state == Lo_bound) |
218 | blk_mq_freeze_queue(lo->lo_queue); | |
2e5ab5f3 | 219 | lo->use_dio = use_dio; |
40326d8a | 220 | if (use_dio) { |
8b904b5b | 221 | blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
2e5ab5f3 | 222 | lo->lo_flags |= LO_FLAGS_DIRECT_IO; |
40326d8a | 223 | } else { |
8b904b5b | 224 | blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
2e5ab5f3 | 225 | lo->lo_flags &= ~LO_FLAGS_DIRECT_IO; |
40326d8a | 226 | } |
0fbcf579 MC |
227 | if (lo->lo_state == Lo_bound) |
228 | blk_mq_unfreeze_queue(lo->lo_queue); | |
2e5ab5f3 ML |
229 | } |
230 | ||
3448914e MC |
231 | /** |
232 | * loop_validate_block_size() - validates the passed in block size | |
233 | * @bsize: size to validate | |
234 | */ | |
1da177e4 | 235 | static int |
3448914e | 236 | loop_validate_block_size(unsigned short bsize) |
1da177e4 | 237 | { |
3448914e MC |
238 | if (bsize < 512 || bsize > PAGE_SIZE || !is_power_of_2(bsize)) |
239 | return -EINVAL; | |
1da177e4 | 240 | |
7035b5df | 241 | return 0; |
1da177e4 LT |
242 | } |
243 | ||
5795b6f5 MC |
244 | /** |
245 | * loop_set_size() - sets device size and notifies userspace | |
246 | * @lo: struct loop_device to set the size for | |
247 | * @size: new size of the loop device | |
248 | * | |
249 | * Callers must validate that the size passed into this function fits into | |
250 | * a sector_t, eg using loop_validate_size() | |
251 | */ | |
252 | static void loop_set_size(struct loop_device *lo, loff_t size) | |
253 | { | |
449f4ec9 | 254 | if (!set_capacity_and_notify(lo->lo_disk, size)) |
3b4f85d0 | 255 | kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); |
5795b6f5 MC |
256 | } |
257 | ||
1da177e4 LT |
258 | static inline int |
259 | lo_do_transfer(struct loop_device *lo, int cmd, | |
260 | struct page *rpage, unsigned roffs, | |
261 | struct page *lpage, unsigned loffs, | |
262 | int size, sector_t rblock) | |
263 | { | |
aa4d8616 CH |
264 | int ret; |
265 | ||
266 | ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); | |
267 | if (likely(!ret)) | |
1da177e4 LT |
268 | return 0; |
269 | ||
aa4d8616 CH |
270 | printk_ratelimited(KERN_ERR |
271 | "loop: Transfer error at byte offset %llu, length %i.\n", | |
272 | (unsigned long long)rblock << 9, size); | |
273 | return ret; | |
1da177e4 LT |
274 | } |
275 | ||
aa4d8616 | 276 | static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) |
1da177e4 | 277 | { |
aa4d8616 | 278 | struct iov_iter i; |
1da177e4 | 279 | ssize_t bw; |
283e7e5d | 280 | |
b6207430 | 281 | iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len); |
1da177e4 | 282 | |
03d95eb2 | 283 | file_start_write(file); |
abbb6589 | 284 | bw = vfs_iter_write(file, &i, ppos, 0); |
03d95eb2 | 285 | file_end_write(file); |
aa4d8616 CH |
286 | |
287 | if (likely(bw == bvec->bv_len)) | |
1da177e4 | 288 | return 0; |
aa4d8616 CH |
289 | |
290 | printk_ratelimited(KERN_ERR | |
291 | "loop: Write error at byte offset %llu, length %i.\n", | |
292 | (unsigned long long)*ppos, bvec->bv_len); | |
1da177e4 LT |
293 | if (bw >= 0) |
294 | bw = -EIO; | |
295 | return bw; | |
296 | } | |
297 | ||
aa4d8616 CH |
298 | static int lo_write_simple(struct loop_device *lo, struct request *rq, |
299 | loff_t pos) | |
1da177e4 | 300 | { |
aa4d8616 CH |
301 | struct bio_vec bvec; |
302 | struct req_iterator iter; | |
303 | int ret = 0; | |
304 | ||
305 | rq_for_each_segment(bvec, rq, iter) { | |
306 | ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos); | |
307 | if (ret < 0) | |
308 | break; | |
309 | cond_resched(); | |
310 | } | |
311 | ||
312 | return ret; | |
1da177e4 LT |
313 | } |
314 | ||
aa4d8616 | 315 | /* |
456be148 CH |
316 | * This is the slow, transforming version that needs to double buffer the |
317 | * data as it cannot do the transformations in place without having direct | |
318 | * access to the destination pages of the backing file. | |
1da177e4 | 319 | */ |
aa4d8616 CH |
320 | static int lo_write_transfer(struct loop_device *lo, struct request *rq, |
321 | loff_t pos) | |
1da177e4 | 322 | { |
aa4d8616 | 323 | struct bio_vec bvec, b; |
30112013 | 324 | struct req_iterator iter; |
aa4d8616 | 325 | struct page *page; |
7988613b | 326 | int ret = 0; |
1da177e4 | 327 | |
aa4d8616 CH |
328 | page = alloc_page(GFP_NOIO); |
329 | if (unlikely(!page)) | |
330 | return -ENOMEM; | |
456be148 | 331 | |
30112013 | 332 | rq_for_each_segment(bvec, rq, iter) { |
aa4d8616 CH |
333 | ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page, |
334 | bvec.bv_offset, bvec.bv_len, pos >> 9); | |
335 | if (unlikely(ret)) | |
336 | break; | |
337 | ||
338 | b.bv_page = page; | |
339 | b.bv_offset = 0; | |
340 | b.bv_len = bvec.bv_len; | |
341 | ret = lo_write_bvec(lo->lo_backing_file, &b, &pos); | |
1da177e4 LT |
342 | if (ret < 0) |
343 | break; | |
1da177e4 | 344 | } |
aa4d8616 CH |
345 | |
346 | __free_page(page); | |
1da177e4 | 347 | return ret; |
1da177e4 LT |
348 | } |
349 | ||
aa4d8616 CH |
350 | static int lo_read_simple(struct loop_device *lo, struct request *rq, |
351 | loff_t pos) | |
1da177e4 | 352 | { |
aa4d8616 CH |
353 | struct bio_vec bvec; |
354 | struct req_iterator iter; | |
355 | struct iov_iter i; | |
356 | ssize_t len; | |
1da177e4 | 357 | |
aa4d8616 | 358 | rq_for_each_segment(bvec, rq, iter) { |
b6207430 | 359 | iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len); |
18e9710e | 360 | len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); |
aa4d8616 CH |
361 | if (len < 0) |
362 | return len; | |
1da177e4 | 363 | |
aa4d8616 | 364 | flush_dcache_page(bvec.bv_page); |
fd582140 | 365 | |
aa4d8616 CH |
366 | if (len != bvec.bv_len) { |
367 | struct bio *bio; | |
1da177e4 | 368 | |
aa4d8616 CH |
369 | __rq_for_each_bio(bio, rq) |
370 | zero_fill_bio(bio); | |
371 | break; | |
372 | } | |
373 | cond_resched(); | |
374 | } | |
375 | ||
376 | return 0; | |
fd582140 JA |
377 | } |
378 | ||
aa4d8616 CH |
379 | static int lo_read_transfer(struct loop_device *lo, struct request *rq, |
380 | loff_t pos) | |
1da177e4 | 381 | { |
aa4d8616 CH |
382 | struct bio_vec bvec, b; |
383 | struct req_iterator iter; | |
384 | struct iov_iter i; | |
385 | struct page *page; | |
386 | ssize_t len; | |
387 | int ret = 0; | |
1da177e4 | 388 | |
aa4d8616 CH |
389 | page = alloc_page(GFP_NOIO); |
390 | if (unlikely(!page)) | |
391 | return -ENOMEM; | |
fd582140 | 392 | |
aa4d8616 CH |
393 | rq_for_each_segment(bvec, rq, iter) { |
394 | loff_t offset = pos; | |
fd582140 | 395 | |
aa4d8616 CH |
396 | b.bv_page = page; |
397 | b.bv_offset = 0; | |
398 | b.bv_len = bvec.bv_len; | |
fd582140 | 399 | |
b6207430 | 400 | iov_iter_bvec(&i, READ, &b, 1, b.bv_len); |
18e9710e | 401 | len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); |
aa4d8616 CH |
402 | if (len < 0) { |
403 | ret = len; | |
404 | goto out_free_page; | |
405 | } | |
1da177e4 | 406 | |
aa4d8616 CH |
407 | ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page, |
408 | bvec.bv_offset, len, offset >> 9); | |
409 | if (ret) | |
410 | goto out_free_page; | |
1da177e4 | 411 | |
aa4d8616 | 412 | flush_dcache_page(bvec.bv_page); |
306df071 | 413 | |
aa4d8616 | 414 | if (len != bvec.bv_len) { |
30112013 ML |
415 | struct bio *bio; |
416 | ||
417 | __rq_for_each_bio(bio, rq) | |
418 | zero_fill_bio(bio); | |
1da177e4 | 419 | break; |
306df071 | 420 | } |
1da177e4 | 421 | } |
aa4d8616 CH |
422 | |
423 | ret = 0; | |
424 | out_free_page: | |
425 | __free_page(page); | |
426 | return ret; | |
1da177e4 LT |
427 | } |
428 | ||
efcfec57 DW |
429 | static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos, |
430 | int mode) | |
cf655d95 ML |
431 | { |
432 | /* | |
efcfec57 DW |
433 | * We use fallocate to manipulate the space mappings used by the image |
434 | * a.k.a. discard/zerorange. However we do not support this if | |
435 | * encryption is enabled, because it may give an attacker useful | |
436 | * information. | |
cf655d95 ML |
437 | */ |
438 | struct file *file = lo->lo_backing_file; | |
c52abf56 | 439 | struct request_queue *q = lo->lo_queue; |
cf655d95 ML |
440 | int ret; |
441 | ||
efcfec57 DW |
442 | mode |= FALLOC_FL_KEEP_SIZE; |
443 | ||
c52abf56 | 444 | if (!blk_queue_discard(q)) { |
cf655d95 ML |
445 | ret = -EOPNOTSUPP; |
446 | goto out; | |
447 | } | |
448 | ||
449 | ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); | |
450 | if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) | |
451 | ret = -EIO; | |
452 | out: | |
453 | return ret; | |
454 | } | |
455 | ||
456 | static int lo_req_flush(struct loop_device *lo, struct request *rq) | |
457 | { | |
458 | struct file *file = lo->lo_backing_file; | |
459 | int ret = vfs_fsync(file, 0); | |
460 | if (unlikely(ret && ret != -EINVAL)) | |
461 | ret = -EIO; | |
462 | ||
463 | return ret; | |
464 | } | |
465 | ||
fe2cb290 | 466 | static void lo_complete_rq(struct request *rq) |
bc07c10a | 467 | { |
fe2cb290 | 468 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); |
f9de14bc | 469 | blk_status_t ret = BLK_STS_OK; |
bc07c10a | 470 | |
f9de14bc JA |
471 | if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || |
472 | req_op(rq) != REQ_OP_READ) { | |
473 | if (cmd->ret < 0) | |
8cd55087 | 474 | ret = errno_to_blk_status(cmd->ret); |
f9de14bc | 475 | goto end_io; |
bc07c10a | 476 | } |
fe2cb290 | 477 | |
f9de14bc JA |
478 | /* |
479 | * Short READ - if we got some data, advance our request and | |
480 | * retry it. If we got no data, end the rest with EIO. | |
481 | */ | |
482 | if (cmd->ret) { | |
483 | blk_update_request(rq, BLK_STS_OK, cmd->ret); | |
484 | cmd->ret = 0; | |
485 | blk_mq_requeue_request(rq, true); | |
486 | } else { | |
487 | if (cmd->use_aio) { | |
488 | struct bio *bio = rq->bio; | |
489 | ||
490 | while (bio) { | |
491 | zero_fill_bio(bio); | |
492 | bio = bio->bi_next; | |
493 | } | |
494 | } | |
495 | ret = BLK_STS_IOERR; | |
496 | end_io: | |
497 | blk_mq_end_request(rq, ret); | |
498 | } | |
bc07c10a ML |
499 | } |
500 | ||
92d77332 SL |
501 | static void lo_rw_aio_do_completion(struct loop_cmd *cmd) |
502 | { | |
1894e916 JA |
503 | struct request *rq = blk_mq_rq_from_pdu(cmd); |
504 | ||
92d77332 SL |
505 | if (!atomic_dec_and_test(&cmd->ref)) |
506 | return; | |
507 | kfree(cmd->bvec); | |
508 | cmd->bvec = NULL; | |
15f73f5b CH |
509 | if (likely(!blk_should_fake_timeout(rq->q))) |
510 | blk_mq_complete_request(rq); | |
92d77332 SL |
511 | } |
512 | ||
bc07c10a ML |
513 | static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) |
514 | { | |
515 | struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); | |
bc07c10a | 516 | |
d4478e92 SL |
517 | if (cmd->css) |
518 | css_put(cmd->css); | |
fe2cb290 | 519 | cmd->ret = ret; |
92d77332 | 520 | lo_rw_aio_do_completion(cmd); |
bc07c10a ML |
521 | } |
522 | ||
523 | static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, | |
524 | loff_t pos, bool rw) | |
525 | { | |
526 | struct iov_iter iter; | |
86af5952 | 527 | struct req_iterator rq_iter; |
bc07c10a | 528 | struct bio_vec *bvec; |
1894e916 | 529 | struct request *rq = blk_mq_rq_from_pdu(cmd); |
40326d8a | 530 | struct bio *bio = rq->bio; |
bc07c10a | 531 | struct file *file = lo->lo_backing_file; |
86af5952 | 532 | struct bio_vec tmp; |
40326d8a | 533 | unsigned int offset; |
86af5952 | 534 | int nr_bvec = 0; |
bc07c10a ML |
535 | int ret; |
536 | ||
86af5952 ML |
537 | rq_for_each_bvec(tmp, rq, rq_iter) |
538 | nr_bvec++; | |
539 | ||
40326d8a | 540 | if (rq->bio != rq->biotail) { |
40326d8a | 541 | |
86af5952 | 542 | bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), |
6da2ec56 | 543 | GFP_NOIO); |
40326d8a SL |
544 | if (!bvec) |
545 | return -EIO; | |
546 | cmd->bvec = bvec; | |
547 | ||
548 | /* | |
549 | * The bios of the request may be started from the middle of | |
550 | * the 'bvec' because of bio splitting, so we can't directly | |
86af5952 | 551 | * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec |
40326d8a SL |
552 | * API will take care of all details for us. |
553 | */ | |
86af5952 | 554 | rq_for_each_bvec(tmp, rq, rq_iter) { |
40326d8a SL |
555 | *bvec = tmp; |
556 | bvec++; | |
557 | } | |
558 | bvec = cmd->bvec; | |
559 | offset = 0; | |
560 | } else { | |
561 | /* | |
562 | * Same here, this bio may be started from the middle of the | |
563 | * 'bvec' because of bio splitting, so offset from the bvec | |
564 | * must be passed to iov iterator | |
565 | */ | |
566 | offset = bio->bi_iter.bi_bvec_done; | |
567 | bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); | |
40326d8a | 568 | } |
92d77332 | 569 | atomic_set(&cmd->ref, 2); |
bc07c10a | 570 | |
b6207430 | 571 | iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); |
40326d8a | 572 | iter.iov_offset = offset; |
bc07c10a ML |
573 | |
574 | cmd->iocb.ki_pos = pos; | |
575 | cmd->iocb.ki_filp = file; | |
576 | cmd->iocb.ki_complete = lo_rw_aio_complete; | |
577 | cmd->iocb.ki_flags = IOCB_DIRECT; | |
d9a08a9e | 578 | cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); |
d4478e92 SL |
579 | if (cmd->css) |
580 | kthread_associate_blkcg(cmd->css); | |
bc07c10a ML |
581 | |
582 | if (rw == WRITE) | |
bb7462b6 | 583 | ret = call_write_iter(file, &cmd->iocb, &iter); |
bc07c10a | 584 | else |
bb7462b6 | 585 | ret = call_read_iter(file, &cmd->iocb, &iter); |
bc07c10a | 586 | |
92d77332 | 587 | lo_rw_aio_do_completion(cmd); |
d4478e92 | 588 | kthread_associate_blkcg(NULL); |
92d77332 | 589 | |
bc07c10a ML |
590 | if (ret != -EIOCBQUEUED) |
591 | cmd->iocb.ki_complete(&cmd->iocb, ret, 0); | |
592 | return 0; | |
593 | } | |
594 | ||
c1c87c2b | 595 | static int do_req_filebacked(struct loop_device *lo, struct request *rq) |
bc07c10a ML |
596 | { |
597 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
c1c87c2b | 598 | loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; |
bc07c10a ML |
599 | |
600 | /* | |
601 | * lo_write_simple and lo_read_simple should have been covered | |
602 | * by io submit style function like lo_rw_aio(), one blocker | |
603 | * is that lo_read_simple() need to call flush_dcache_page after | |
604 | * the page is written from kernel, and it isn't easy to handle | |
605 | * this in io submit style function which submits all segments | |
606 | * of the req at one time. And direct read IO doesn't need to | |
607 | * run flush_dcache_page(). | |
608 | */ | |
c1c87c2b CH |
609 | switch (req_op(rq)) { |
610 | case REQ_OP_FLUSH: | |
611 | return lo_req_flush(lo, rq); | |
19372e27 | 612 | case REQ_OP_WRITE_ZEROES: |
efcfec57 DW |
613 | /* |
614 | * If the caller doesn't want deallocation, call zeroout to | |
615 | * write zeroes the range. Otherwise, punch them out. | |
616 | */ | |
617 | return lo_fallocate(lo, rq, pos, | |
618 | (rq->cmd_flags & REQ_NOUNMAP) ? | |
619 | FALLOC_FL_ZERO_RANGE : | |
620 | FALLOC_FL_PUNCH_HOLE); | |
621 | case REQ_OP_DISCARD: | |
622 | return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE); | |
c1c87c2b CH |
623 | case REQ_OP_WRITE: |
624 | if (lo->transfer) | |
625 | return lo_write_transfer(lo, rq, pos); | |
626 | else if (cmd->use_aio) | |
627 | return lo_rw_aio(lo, cmd, pos, WRITE); | |
af65aa8e | 628 | else |
c1c87c2b CH |
629 | return lo_write_simple(lo, rq, pos); |
630 | case REQ_OP_READ: | |
aa4d8616 | 631 | if (lo->transfer) |
c1c87c2b CH |
632 | return lo_read_transfer(lo, rq, pos); |
633 | else if (cmd->use_aio) | |
634 | return lo_rw_aio(lo, cmd, pos, READ); | |
aa4d8616 | 635 | else |
c1c87c2b CH |
636 | return lo_read_simple(lo, rq, pos); |
637 | default: | |
638 | WARN_ON_ONCE(1); | |
639 | return -EIO; | |
aa4d8616 | 640 | } |
1da177e4 LT |
641 | } |
642 | ||
2e5ab5f3 ML |
643 | static inline void loop_update_dio(struct loop_device *lo) |
644 | { | |
efbe3c24 IW |
645 | __loop_update_dio(lo, (lo->lo_backing_file->f_flags & O_DIRECT) | |
646 | lo->use_dio); | |
2e5ab5f3 ML |
647 | } |
648 | ||
06f0e9e6 ML |
649 | static void loop_reread_partitions(struct loop_device *lo, |
650 | struct block_device *bdev) | |
651 | { | |
652 | int rc; | |
653 | ||
f0b870df CH |
654 | mutex_lock(&bdev->bd_mutex); |
655 | rc = bdev_disk_changed(bdev, false); | |
656 | mutex_unlock(&bdev->bd_mutex); | |
06f0e9e6 ML |
657 | if (rc) |
658 | pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", | |
659 | __func__, lo->lo_number, lo->lo_file_name, rc); | |
660 | } | |
661 | ||
d2ac838e TT |
662 | static inline int is_loop_device(struct file *file) |
663 | { | |
664 | struct inode *i = file->f_mapping->host; | |
665 | ||
666 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; | |
667 | } | |
668 | ||
669 | static int loop_validate_file(struct file *file, struct block_device *bdev) | |
670 | { | |
671 | struct inode *inode = file->f_mapping->host; | |
672 | struct file *f = file; | |
673 | ||
674 | /* Avoid recursion */ | |
675 | while (is_loop_device(f)) { | |
676 | struct loop_device *l; | |
677 | ||
4e7b5671 | 678 | if (f->f_mapping->host->i_rdev == bdev->bd_dev) |
d2ac838e TT |
679 | return -EBADF; |
680 | ||
4e7b5671 | 681 | l = I_BDEV(f->f_mapping->host)->bd_disk->private_data; |
f7c8a412 | 682 | if (l->lo_state != Lo_bound) { |
d2ac838e TT |
683 | return -EINVAL; |
684 | } | |
685 | f = l->lo_backing_file; | |
686 | } | |
687 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
688 | return -EINVAL; | |
689 | return 0; | |
690 | } | |
691 | ||
1da177e4 LT |
692 | /* |
693 | * loop_change_fd switched the backing store of a loopback device to | |
694 | * a new file. This is useful for operating system installers to free up | |
695 | * the original file and in High Availability environments to switch to | |
696 | * an alternative location for the content in case of server meltdown. | |
697 | * This can only work if the loop device is used read-only, and if the | |
698 | * new backing store is the same size and type as the old backing store. | |
699 | */ | |
bb214884 AV |
700 | static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
701 | unsigned int arg) | |
1da177e4 | 702 | { |
1dded9ac | 703 | struct file *file = NULL, *old_file; |
1da177e4 | 704 | int error; |
85b0a54a | 705 | bool partscan; |
1da177e4 | 706 | |
c28445fa | 707 | error = mutex_lock_killable(&loop_ctl_mutex); |
c3710770 JK |
708 | if (error) |
709 | return error; | |
1da177e4 LT |
710 | error = -ENXIO; |
711 | if (lo->lo_state != Lo_bound) | |
1dded9ac | 712 | goto out_err; |
1da177e4 LT |
713 | |
714 | /* the loop device has to be read-only */ | |
715 | error = -EINVAL; | |
716 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) | |
1dded9ac | 717 | goto out_err; |
1da177e4 LT |
718 | |
719 | error = -EBADF; | |
720 | file = fget(arg); | |
721 | if (!file) | |
1dded9ac | 722 | goto out_err; |
1da177e4 | 723 | |
d2ac838e TT |
724 | error = loop_validate_file(file, bdev); |
725 | if (error) | |
1dded9ac | 726 | goto out_err; |
d2ac838e | 727 | |
1da177e4 LT |
728 | old_file = lo->lo_backing_file; |
729 | ||
730 | error = -EINVAL; | |
731 | ||
1da177e4 LT |
732 | /* size of the new backing store needs to be the same */ |
733 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) | |
1dded9ac | 734 | goto out_err; |
1da177e4 LT |
735 | |
736 | /* and ... switch */ | |
43cade80 OS |
737 | blk_mq_freeze_queue(lo->lo_queue); |
738 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); | |
739 | lo->lo_backing_file = file; | |
740 | lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping); | |
741 | mapping_set_gfp_mask(file->f_mapping, | |
742 | lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
743 | loop_update_dio(lo); | |
744 | blk_mq_unfreeze_queue(lo->lo_queue); | |
85b0a54a | 745 | partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; |
c3710770 | 746 | mutex_unlock(&loop_ctl_mutex); |
1dded9ac JK |
747 | /* |
748 | * We must drop file reference outside of loop_ctl_mutex as dropping | |
749 | * the file ref can take bd_mutex which creates circular locking | |
750 | * dependency. | |
751 | */ | |
752 | fput(old_file); | |
85b0a54a JK |
753 | if (partscan) |
754 | loop_reread_partitions(lo, bdev); | |
1da177e4 LT |
755 | return 0; |
756 | ||
1dded9ac | 757 | out_err: |
c3710770 | 758 | mutex_unlock(&loop_ctl_mutex); |
1dded9ac JK |
759 | if (file) |
760 | fput(file); | |
1da177e4 LT |
761 | return error; |
762 | } | |
763 | ||
ee862730 MB |
764 | /* loop sysfs attributes */ |
765 | ||
766 | static ssize_t loop_attr_show(struct device *dev, char *page, | |
767 | ssize_t (*callback)(struct loop_device *, char *)) | |
768 | { | |
34dd82af KS |
769 | struct gendisk *disk = dev_to_disk(dev); |
770 | struct loop_device *lo = disk->private_data; | |
ee862730 | 771 | |
34dd82af | 772 | return callback(lo, page); |
ee862730 MB |
773 | } |
774 | ||
775 | #define LOOP_ATTR_RO(_name) \ | |
776 | static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ | |
777 | static ssize_t loop_attr_do_show_##_name(struct device *d, \ | |
778 | struct device_attribute *attr, char *b) \ | |
779 | { \ | |
780 | return loop_attr_show(d, b, loop_attr_##_name##_show); \ | |
781 | } \ | |
782 | static struct device_attribute loop_attr_##_name = \ | |
5657a819 | 783 | __ATTR(_name, 0444, loop_attr_do_show_##_name, NULL); |
ee862730 MB |
784 | |
785 | static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) | |
786 | { | |
787 | ssize_t ret; | |
788 | char *p = NULL; | |
789 | ||
05eb0f25 | 790 | spin_lock_irq(&lo->lo_lock); |
ee862730 | 791 | if (lo->lo_backing_file) |
9bf39ab2 | 792 | p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1); |
05eb0f25 | 793 | spin_unlock_irq(&lo->lo_lock); |
ee862730 MB |
794 | |
795 | if (IS_ERR_OR_NULL(p)) | |
796 | ret = PTR_ERR(p); | |
797 | else { | |
798 | ret = strlen(p); | |
799 | memmove(buf, p, ret); | |
800 | buf[ret++] = '\n'; | |
801 | buf[ret] = 0; | |
802 | } | |
803 | ||
804 | return ret; | |
805 | } | |
806 | ||
807 | static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) | |
808 | { | |
809 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); | |
810 | } | |
811 | ||
812 | static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) | |
813 | { | |
814 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); | |
815 | } | |
816 | ||
817 | static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) | |
818 | { | |
819 | int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); | |
820 | ||
821 | return sprintf(buf, "%s\n", autoclear ? "1" : "0"); | |
822 | } | |
823 | ||
e03c8dd1 KS |
824 | static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf) |
825 | { | |
826 | int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN); | |
827 | ||
828 | return sprintf(buf, "%s\n", partscan ? "1" : "0"); | |
829 | } | |
830 | ||
2e5ab5f3 ML |
831 | static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf) |
832 | { | |
833 | int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO); | |
834 | ||
835 | return sprintf(buf, "%s\n", dio ? "1" : "0"); | |
836 | } | |
837 | ||
ee862730 MB |
838 | LOOP_ATTR_RO(backing_file); |
839 | LOOP_ATTR_RO(offset); | |
840 | LOOP_ATTR_RO(sizelimit); | |
841 | LOOP_ATTR_RO(autoclear); | |
e03c8dd1 | 842 | LOOP_ATTR_RO(partscan); |
2e5ab5f3 | 843 | LOOP_ATTR_RO(dio); |
ee862730 MB |
844 | |
845 | static struct attribute *loop_attrs[] = { | |
846 | &loop_attr_backing_file.attr, | |
847 | &loop_attr_offset.attr, | |
848 | &loop_attr_sizelimit.attr, | |
849 | &loop_attr_autoclear.attr, | |
e03c8dd1 | 850 | &loop_attr_partscan.attr, |
2e5ab5f3 | 851 | &loop_attr_dio.attr, |
ee862730 MB |
852 | NULL, |
853 | }; | |
854 | ||
855 | static struct attribute_group loop_attribute_group = { | |
856 | .name = "loop", | |
857 | .attrs= loop_attrs, | |
858 | }; | |
859 | ||
d3349b6b | 860 | static void loop_sysfs_init(struct loop_device *lo) |
ee862730 | 861 | { |
d3349b6b TH |
862 | lo->sysfs_inited = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, |
863 | &loop_attribute_group); | |
ee862730 MB |
864 | } |
865 | ||
866 | static void loop_sysfs_exit(struct loop_device *lo) | |
867 | { | |
d3349b6b TH |
868 | if (lo->sysfs_inited) |
869 | sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, | |
870 | &loop_attribute_group); | |
ee862730 MB |
871 | } |
872 | ||
dfaa2ef6 LC |
873 | static void loop_config_discard(struct loop_device *lo) |
874 | { | |
875 | struct file *file = lo->lo_backing_file; | |
876 | struct inode *inode = file->f_mapping->host; | |
877 | struct request_queue *q = lo->lo_queue; | |
bcb21c8c | 878 | u32 granularity, max_discard_sectors; |
dfaa2ef6 | 879 | |
c52abf56 EG |
880 | /* |
881 | * If the backing device is a block device, mirror its zeroing | |
882 | * capability. Set the discard sectors to the block device's zeroing | |
883 | * capabilities because loop discards result in blkdev_issue_zeroout(), | |
884 | * not blkdev_issue_discard(). This maintains consistent behavior with | |
885 | * file-backed loop devices: discarded regions read back as zero. | |
886 | */ | |
887 | if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) { | |
4e7b5671 | 888 | struct request_queue *backingq = bdev_get_queue(I_BDEV(inode)); |
c52abf56 | 889 | |
bcb21c8c ML |
890 | max_discard_sectors = backingq->limits.max_write_zeroes_sectors; |
891 | granularity = backingq->limits.discard_granularity ?: | |
892 | queue_physical_block_size(backingq); | |
c52abf56 | 893 | |
dfaa2ef6 LC |
894 | /* |
895 | * We use punch hole to reclaim the free space used by the | |
12a64d2f | 896 | * image a.k.a. discard. However we do not support discard if |
dfaa2ef6 LC |
897 | * encryption is enabled, because it may give an attacker |
898 | * useful information. | |
899 | */ | |
c52abf56 | 900 | } else if (!file->f_op->fallocate || lo->lo_encrypt_key_size) { |
bcb21c8c ML |
901 | max_discard_sectors = 0; |
902 | granularity = 0; | |
dfaa2ef6 | 903 | |
c52abf56 | 904 | } else { |
bcb21c8c ML |
905 | max_discard_sectors = UINT_MAX >> 9; |
906 | granularity = inode->i_sb->s_blocksize; | |
c52abf56 EG |
907 | } |
908 | ||
bcb21c8c ML |
909 | if (max_discard_sectors) { |
910 | q->limits.discard_granularity = granularity; | |
911 | blk_queue_max_discard_sectors(q, max_discard_sectors); | |
912 | blk_queue_max_write_zeroes_sectors(q, max_discard_sectors); | |
c52abf56 | 913 | blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); |
bcb21c8c ML |
914 | } else { |
915 | q->limits.discard_granularity = 0; | |
916 | blk_queue_max_discard_sectors(q, 0); | |
917 | blk_queue_max_write_zeroes_sectors(q, 0); | |
c52abf56 | 918 | blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); |
bcb21c8c ML |
919 | } |
920 | q->limits.discard_alignment = 0; | |
dfaa2ef6 LC |
921 | } |
922 | ||
e03a3d7a ML |
923 | static void loop_unprepare_queue(struct loop_device *lo) |
924 | { | |
3989144f | 925 | kthread_flush_worker(&lo->worker); |
e03a3d7a ML |
926 | kthread_stop(lo->worker_task); |
927 | } | |
928 | ||
b2ee7d46 N |
929 | static int loop_kthread_worker_fn(void *worker_ptr) |
930 | { | |
a37b0715 | 931 | current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; |
b2ee7d46 N |
932 | return kthread_worker_fn(worker_ptr); |
933 | } | |
934 | ||
e03a3d7a ML |
935 | static int loop_prepare_queue(struct loop_device *lo) |
936 | { | |
3989144f | 937 | kthread_init_worker(&lo->worker); |
b2ee7d46 | 938 | lo->worker_task = kthread_run(loop_kthread_worker_fn, |
e03a3d7a ML |
939 | &lo->worker, "loop%d", lo->lo_number); |
940 | if (IS_ERR(lo->worker_task)) | |
941 | return -ENOMEM; | |
942 | set_user_nice(lo->worker_task, MIN_NICE); | |
943 | return 0; | |
944 | } | |
945 | ||
56a85fd8 HH |
946 | static void loop_update_rotational(struct loop_device *lo) |
947 | { | |
948 | struct file *file = lo->lo_backing_file; | |
949 | struct inode *file_inode = file->f_mapping->host; | |
950 | struct block_device *file_bdev = file_inode->i_sb->s_bdev; | |
951 | struct request_queue *q = lo->lo_queue; | |
952 | bool nonrot = true; | |
953 | ||
954 | /* not all filesystems (e.g. tmpfs) have a sb->s_bdev */ | |
955 | if (file_bdev) | |
956 | nonrot = blk_queue_nonrot(bdev_get_queue(file_bdev)); | |
957 | ||
958 | if (nonrot) | |
959 | blk_queue_flag_set(QUEUE_FLAG_NONROT, q); | |
960 | else | |
961 | blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); | |
962 | } | |
963 | ||
62ab466c MC |
964 | static int |
965 | loop_release_xfer(struct loop_device *lo) | |
966 | { | |
967 | int err = 0; | |
968 | struct loop_func_table *xfer = lo->lo_encryption; | |
969 | ||
970 | if (xfer) { | |
971 | if (xfer->release) | |
972 | err = xfer->release(lo); | |
973 | lo->transfer = NULL; | |
974 | lo->lo_encryption = NULL; | |
975 | module_put(xfer->owner); | |
976 | } | |
977 | return err; | |
978 | } | |
979 | ||
980 | static int | |
981 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, | |
982 | const struct loop_info64 *i) | |
983 | { | |
984 | int err = 0; | |
985 | ||
986 | if (xfer) { | |
987 | struct module *owner = xfer->owner; | |
988 | ||
989 | if (!try_module_get(owner)) | |
990 | return -EINVAL; | |
991 | if (xfer->init) | |
992 | err = xfer->init(lo, i); | |
993 | if (err) | |
994 | module_put(owner); | |
995 | else | |
996 | lo->lo_encryption = xfer; | |
997 | } | |
998 | return err; | |
999 | } | |
1000 | ||
1001 | /** | |
1002 | * loop_set_status_from_info - configure device from loop_info | |
1003 | * @lo: struct loop_device to configure | |
1004 | * @info: struct loop_info64 to configure the device with | |
1005 | * | |
1006 | * Configures the loop device parameters according to the passed | |
1007 | * in loop_info64 configuration. | |
1008 | */ | |
1009 | static int | |
1010 | loop_set_status_from_info(struct loop_device *lo, | |
1011 | const struct loop_info64 *info) | |
1012 | { | |
1013 | int err; | |
1014 | struct loop_func_table *xfer; | |
1015 | kuid_t uid = current_uid(); | |
1016 | ||
1017 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) | |
1018 | return -EINVAL; | |
1019 | ||
1020 | err = loop_release_xfer(lo); | |
1021 | if (err) | |
1022 | return err; | |
1023 | ||
1024 | if (info->lo_encrypt_type) { | |
1025 | unsigned int type = info->lo_encrypt_type; | |
1026 | ||
1027 | if (type >= MAX_LO_CRYPT) | |
1028 | return -EINVAL; | |
1029 | xfer = xfer_funcs[type]; | |
1030 | if (xfer == NULL) | |
1031 | return -EINVAL; | |
1032 | } else | |
1033 | xfer = NULL; | |
1034 | ||
1035 | err = loop_init_xfer(lo, xfer, info); | |
1036 | if (err) | |
1037 | return err; | |
1038 | ||
1039 | lo->lo_offset = info->lo_offset; | |
1040 | lo->lo_sizelimit = info->lo_sizelimit; | |
1041 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); | |
1042 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); | |
1043 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; | |
1044 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; | |
1045 | ||
1046 | if (!xfer) | |
1047 | xfer = &none_funcs; | |
1048 | lo->transfer = xfer->transfer; | |
1049 | lo->ioctl = xfer->ioctl; | |
1050 | ||
faf1d254 | 1051 | lo->lo_flags = info->lo_flags; |
62ab466c MC |
1052 | |
1053 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; | |
1054 | lo->lo_init[0] = info->lo_init[0]; | |
1055 | lo->lo_init[1] = info->lo_init[1]; | |
1056 | if (info->lo_encrypt_key_size) { | |
1057 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, | |
1058 | info->lo_encrypt_key_size); | |
1059 | lo->lo_key_owner = uid; | |
1060 | } | |
1061 | ||
1062 | return 0; | |
1063 | } | |
1064 | ||
3448914e MC |
1065 | static int loop_configure(struct loop_device *lo, fmode_t mode, |
1066 | struct block_device *bdev, | |
1067 | const struct loop_config *config) | |
1da177e4 | 1068 | { |
d2ac838e | 1069 | struct file *file; |
1da177e4 LT |
1070 | struct inode *inode; |
1071 | struct address_space *mapping; | |
1da177e4 LT |
1072 | int error; |
1073 | loff_t size; | |
85b0a54a | 1074 | bool partscan; |
3448914e | 1075 | unsigned short bsize; |
1da177e4 LT |
1076 | |
1077 | /* This is safe, since we have a reference from open(). */ | |
1078 | __module_get(THIS_MODULE); | |
1079 | ||
1080 | error = -EBADF; | |
3448914e | 1081 | file = fget(config->fd); |
1da177e4 LT |
1082 | if (!file) |
1083 | goto out; | |
1084 | ||
33ec3e53 JK |
1085 | /* |
1086 | * If we don't hold exclusive handle for the device, upgrade to it | |
1087 | * here to avoid changing device under exclusive owner. | |
1088 | */ | |
1089 | if (!(mode & FMODE_EXCL)) { | |
37c3fc9a | 1090 | error = bd_prepare_to_claim(bdev, loop_configure); |
ecbe6bc0 | 1091 | if (error) |
33ec3e53 JK |
1092 | goto out_putf; |
1093 | } | |
1094 | ||
c28445fa | 1095 | error = mutex_lock_killable(&loop_ctl_mutex); |
757ecf40 | 1096 | if (error) |
33ec3e53 | 1097 | goto out_bdev; |
757ecf40 | 1098 | |
1da177e4 LT |
1099 | error = -EBUSY; |
1100 | if (lo->lo_state != Lo_unbound) | |
757ecf40 | 1101 | goto out_unlock; |
1da177e4 | 1102 | |
d2ac838e TT |
1103 | error = loop_validate_file(file, bdev); |
1104 | if (error) | |
757ecf40 | 1105 | goto out_unlock; |
1da177e4 LT |
1106 | |
1107 | mapping = file->f_mapping; | |
1108 | inode = mapping->host; | |
1109 | ||
3448914e MC |
1110 | if ((config->info.lo_flags & ~LOOP_CONFIGURE_SETTABLE_FLAGS) != 0) { |
1111 | error = -EINVAL; | |
1112 | goto out_unlock; | |
1113 | } | |
1114 | ||
1115 | if (config->block_size) { | |
1116 | error = loop_validate_block_size(config->block_size); | |
1117 | if (error) | |
1118 | goto out_unlock; | |
1119 | } | |
1120 | ||
1121 | error = loop_set_status_from_info(lo, &config->info); | |
1122 | if (error) | |
1123 | goto out_unlock; | |
1124 | ||
456be148 | 1125 | if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || |
283e7e5d | 1126 | !file->f_op->write_iter) |
3448914e | 1127 | lo->lo_flags |= LO_FLAGS_READ_ONLY; |
ba52de12 | 1128 | |
e03a3d7a ML |
1129 | error = loop_prepare_queue(lo); |
1130 | if (error) | |
757ecf40 | 1131 | goto out_unlock; |
1da177e4 | 1132 | |
7a2f0ce1 | 1133 | set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0); |
1da177e4 | 1134 | |
3448914e | 1135 | lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO; |
1da177e4 | 1136 | lo->lo_device = bdev; |
1da177e4 | 1137 | lo->lo_backing_file = file; |
1da177e4 LT |
1138 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
1139 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
1140 | ||
3448914e | 1141 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
21d0727f | 1142 | blk_queue_write_cache(lo->lo_queue, true, false); |
68db1961 | 1143 | |
3448914e MC |
1144 | if (config->block_size) |
1145 | bsize = config->block_size; | |
96ed320d | 1146 | else if ((lo->lo_backing_file->f_flags & O_DIRECT) && inode->i_sb->s_bdev) |
85560117 | 1147 | /* In case of direct I/O, match underlying block size */ |
3448914e MC |
1148 | bsize = bdev_logical_block_size(inode->i_sb->s_bdev); |
1149 | else | |
1150 | bsize = 512; | |
85560117 | 1151 | |
3448914e MC |
1152 | blk_queue_logical_block_size(lo->lo_queue, bsize); |
1153 | blk_queue_physical_block_size(lo->lo_queue, bsize); | |
1154 | blk_queue_io_min(lo->lo_queue, bsize); | |
85560117 | 1155 | |
56a85fd8 | 1156 | loop_update_rotational(lo); |
2e5ab5f3 | 1157 | loop_update_dio(lo); |
ee862730 | 1158 | loop_sysfs_init(lo); |
79e5dc59 MC |
1159 | |
1160 | size = get_loop_size(lo, file); | |
5795b6f5 | 1161 | loop_set_size(lo, size); |
1da177e4 | 1162 | |
6c997918 | 1163 | lo->lo_state = Lo_bound; |
e03c8dd1 KS |
1164 | if (part_shift) |
1165 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
85b0a54a | 1166 | partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; |
fe6a8fc5 LP |
1167 | if (partscan) |
1168 | lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; | |
c1681bf8 AP |
1169 | |
1170 | /* Grab the block_device to prevent its destruction after we | |
a2505b79 | 1171 | * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev). |
c1681bf8 AP |
1172 | */ |
1173 | bdgrab(bdev); | |
757ecf40 | 1174 | mutex_unlock(&loop_ctl_mutex); |
85b0a54a JK |
1175 | if (partscan) |
1176 | loop_reread_partitions(lo, bdev); | |
37c3fc9a CH |
1177 | if (!(mode & FMODE_EXCL)) |
1178 | bd_abort_claiming(bdev, loop_configure); | |
1da177e4 LT |
1179 | return 0; |
1180 | ||
757ecf40 JK |
1181 | out_unlock: |
1182 | mutex_unlock(&loop_ctl_mutex); | |
33ec3e53 | 1183 | out_bdev: |
37c3fc9a CH |
1184 | if (!(mode & FMODE_EXCL)) |
1185 | bd_abort_claiming(bdev, loop_configure); | |
757ecf40 | 1186 | out_putf: |
1da177e4 | 1187 | fput(file); |
757ecf40 | 1188 | out: |
1da177e4 LT |
1189 | /* This is safe: open() is still holding a reference. */ |
1190 | module_put(THIS_MODULE); | |
1191 | return error; | |
1192 | } | |
1193 | ||
0da03cab | 1194 | static int __loop_clr_fd(struct loop_device *lo, bool release) |
1da177e4 | 1195 | { |
7ccd0791 | 1196 | struct file *filp = NULL; |
b4e3ca1a | 1197 | gfp_t gfp = lo->old_gfp_mask; |
4c823cc3 | 1198 | struct block_device *bdev = lo->lo_device; |
7ccd0791 | 1199 | int err = 0; |
0da03cab JK |
1200 | bool partscan = false; |
1201 | int lo_number; | |
1da177e4 | 1202 | |
7ccd0791 JK |
1203 | mutex_lock(&loop_ctl_mutex); |
1204 | if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) { | |
1205 | err = -ENXIO; | |
1206 | goto out_unlock; | |
1207 | } | |
1da177e4 | 1208 | |
7ccd0791 JK |
1209 | filp = lo->lo_backing_file; |
1210 | if (filp == NULL) { | |
1211 | err = -EINVAL; | |
1212 | goto out_unlock; | |
1213 | } | |
1da177e4 | 1214 | |
f8933667 ML |
1215 | /* freeze request queue during the transition */ |
1216 | blk_mq_freeze_queue(lo->lo_queue); | |
1217 | ||
1da177e4 | 1218 | spin_lock_irq(&lo->lo_lock); |
1da177e4 | 1219 | lo->lo_backing_file = NULL; |
05eb0f25 | 1220 | spin_unlock_irq(&lo->lo_lock); |
1da177e4 LT |
1221 | |
1222 | loop_release_xfer(lo); | |
1223 | lo->transfer = NULL; | |
1224 | lo->ioctl = NULL; | |
1225 | lo->lo_device = NULL; | |
1226 | lo->lo_encryption = NULL; | |
1227 | lo->lo_offset = 0; | |
1228 | lo->lo_sizelimit = 0; | |
1229 | lo->lo_encrypt_key_size = 0; | |
1da177e4 LT |
1230 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
1231 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); | |
1232 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); | |
89e4fdec | 1233 | blk_queue_logical_block_size(lo->lo_queue, 512); |
bf093753 OS |
1234 | blk_queue_physical_block_size(lo->lo_queue, 512); |
1235 | blk_queue_io_min(lo->lo_queue, 512); | |
c1681bf8 AP |
1236 | if (bdev) { |
1237 | bdput(bdev); | |
bb214884 | 1238 | invalidate_bdev(bdev); |
eedffa28 | 1239 | bdev->bd_inode->i_mapping->wb_err = 0; |
c1681bf8 | 1240 | } |
73285082 | 1241 | set_capacity(lo->lo_disk, 0); |
51a0bb0c | 1242 | loop_sysfs_exit(lo); |
c3473c63 | 1243 | if (bdev) { |
c3473c63 DZ |
1244 | /* let user-space know about this change */ |
1245 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1246 | } | |
1da177e4 | 1247 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
1da177e4 LT |
1248 | /* This is safe: open() is still holding a reference. */ |
1249 | module_put(THIS_MODULE); | |
f8933667 ML |
1250 | blk_mq_unfreeze_queue(lo->lo_queue); |
1251 | ||
0da03cab JK |
1252 | partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev; |
1253 | lo_number = lo->lo_number; | |
0da03cab JK |
1254 | loop_unprepare_queue(lo); |
1255 | out_unlock: | |
1256 | mutex_unlock(&loop_ctl_mutex); | |
1257 | if (partscan) { | |
d57f3374 JK |
1258 | /* |
1259 | * bd_mutex has been held already in release path, so don't | |
1260 | * acquire it if this function is called in such case. | |
1261 | * | |
1262 | * If the reread partition isn't from release path, lo_refcnt | |
1263 | * must be at least one and it can only become zero when the | |
1264 | * current holder is released. | |
1265 | */ | |
f0b870df CH |
1266 | if (!release) |
1267 | mutex_lock(&bdev->bd_mutex); | |
1268 | err = bdev_disk_changed(bdev, false); | |
1269 | if (!release) | |
1270 | mutex_unlock(&bdev->bd_mutex); | |
40853d6f DZ |
1271 | if (err) |
1272 | pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", | |
1273 | __func__, lo_number, err); | |
d57f3374 JK |
1274 | /* Device is gone, no point in returning error */ |
1275 | err = 0; | |
1276 | } | |
758a58d0 DZ |
1277 | |
1278 | /* | |
1279 | * lo->lo_state is set to Lo_unbound here after above partscan has | |
1280 | * finished. | |
1281 | * | |
1282 | * There cannot be anybody else entering __loop_clr_fd() as | |
1283 | * lo->lo_backing_file is already cleared and Lo_rundown state | |
1284 | * protects us from all the other places trying to change the 'lo' | |
1285 | * device. | |
1286 | */ | |
1287 | mutex_lock(&loop_ctl_mutex); | |
1288 | lo->lo_flags = 0; | |
1289 | if (!part_shift) | |
1290 | lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; | |
1291 | lo->lo_state = Lo_unbound; | |
1292 | mutex_unlock(&loop_ctl_mutex); | |
1293 | ||
f028f3b2 | 1294 | /* |
310ca162 TH |
1295 | * Need not hold loop_ctl_mutex to fput backing file. |
1296 | * Calling fput holding loop_ctl_mutex triggers a circular | |
f028f3b2 | 1297 | * lock dependency possibility warning as fput can take |
310ca162 | 1298 | * bd_mutex which is usually taken before loop_ctl_mutex. |
f028f3b2 | 1299 | */ |
7ccd0791 JK |
1300 | if (filp) |
1301 | fput(filp); | |
1302 | return err; | |
1da177e4 LT |
1303 | } |
1304 | ||
a2505b79 JK |
1305 | static int loop_clr_fd(struct loop_device *lo) |
1306 | { | |
7ccd0791 JK |
1307 | int err; |
1308 | ||
c28445fa | 1309 | err = mutex_lock_killable(&loop_ctl_mutex); |
7ccd0791 JK |
1310 | if (err) |
1311 | return err; | |
1312 | if (lo->lo_state != Lo_bound) { | |
1313 | mutex_unlock(&loop_ctl_mutex); | |
a2505b79 | 1314 | return -ENXIO; |
7ccd0791 | 1315 | } |
a2505b79 JK |
1316 | /* |
1317 | * If we've explicitly asked to tear down the loop device, | |
1318 | * and it has an elevated reference count, set it for auto-teardown when | |
1319 | * the last reference goes away. This stops $!~#$@ udev from | |
1320 | * preventing teardown because it decided that it needs to run blkid on | |
1321 | * the loopback device whenever they appear. xfstests is notorious for | |
1322 | * failing tests because blkid via udev races with a losetup | |
1323 | * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d | |
1324 | * command to fail with EBUSY. | |
1325 | */ | |
1326 | if (atomic_read(&lo->lo_refcnt) > 1) { | |
1327 | lo->lo_flags |= LO_FLAGS_AUTOCLEAR; | |
1328 | mutex_unlock(&loop_ctl_mutex); | |
1329 | return 0; | |
1330 | } | |
1331 | lo->lo_state = Lo_rundown; | |
7ccd0791 | 1332 | mutex_unlock(&loop_ctl_mutex); |
a2505b79 | 1333 | |
0da03cab | 1334 | return __loop_clr_fd(lo, false); |
a2505b79 JK |
1335 | } |
1336 | ||
1da177e4 LT |
1337 | static int |
1338 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) | |
1339 | { | |
1340 | int err; | |
85b0a54a | 1341 | struct block_device *bdev; |
0c3796c2 | 1342 | kuid_t uid = current_uid(); |
faf1d254 | 1343 | int prev_lo_flags; |
85b0a54a | 1344 | bool partscan = false; |
0c3796c2 | 1345 | bool size_changed = false; |
1da177e4 | 1346 | |
c28445fa | 1347 | err = mutex_lock_killable(&loop_ctl_mutex); |
550df5fd JK |
1348 | if (err) |
1349 | return err; | |
b0fafa81 | 1350 | if (lo->lo_encrypt_key_size && |
e4849737 | 1351 | !uid_eq(lo->lo_key_owner, uid) && |
550df5fd JK |
1352 | !capable(CAP_SYS_ADMIN)) { |
1353 | err = -EPERM; | |
1354 | goto out_unlock; | |
1355 | } | |
1356 | if (lo->lo_state != Lo_bound) { | |
1357 | err = -ENXIO; | |
1358 | goto out_unlock; | |
1359 | } | |
1da177e4 | 1360 | |
5db470e2 JK |
1361 | if (lo->lo_offset != info->lo_offset || |
1362 | lo->lo_sizelimit != info->lo_sizelimit) { | |
0c3796c2 | 1363 | size_changed = true; |
5db470e2 | 1364 | sync_blockdev(lo->lo_device); |
f4bd34b1 | 1365 | invalidate_bdev(lo->lo_device); |
5db470e2 JK |
1366 | } |
1367 | ||
ecdd0959 ML |
1368 | /* I/O need to be drained during transfer transition */ |
1369 | blk_mq_freeze_queue(lo->lo_queue); | |
1370 | ||
0c3796c2 | 1371 | if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) { |
f4bd34b1 | 1372 | /* If any pages were dirtied after invalidate_bdev(), try again */ |
0c3796c2 MC |
1373 | err = -EAGAIN; |
1374 | pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", | |
1375 | __func__, lo->lo_number, lo->lo_file_name, | |
1376 | lo->lo_device->bd_inode->i_mapping->nrpages); | |
550df5fd | 1377 | goto out_unfreeze; |
0c3796c2 | 1378 | } |
1da177e4 | 1379 | |
faf1d254 | 1380 | prev_lo_flags = lo->lo_flags; |
1da177e4 | 1381 | |
0c3796c2 | 1382 | err = loop_set_status_from_info(lo, info); |
1da177e4 | 1383 | if (err) |
550df5fd | 1384 | goto out_unfreeze; |
1da177e4 | 1385 | |
faf1d254 | 1386 | /* Mask out flags that can't be set using LOOP_SET_STATUS. */ |
6ac92fb5 | 1387 | lo->lo_flags &= LOOP_SET_STATUS_SETTABLE_FLAGS; |
faf1d254 MC |
1388 | /* For those flags, use the previous values instead */ |
1389 | lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_SETTABLE_FLAGS; | |
1390 | /* For flags that can't be cleared, use previous values too */ | |
1391 | lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_CLEARABLE_FLAGS; | |
1392 | ||
b0bd158d MC |
1393 | if (size_changed) { |
1394 | loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit, | |
1395 | lo->lo_backing_file); | |
1396 | loop_set_size(lo, new_size); | |
b040ad9c | 1397 | } |
541c742a | 1398 | |
dfaa2ef6 | 1399 | loop_config_discard(lo); |
1da177e4 | 1400 | |
2e5ab5f3 ML |
1401 | /* update dio if lo_offset or transfer is changed */ |
1402 | __loop_update_dio(lo, lo->use_dio); | |
1403 | ||
550df5fd | 1404 | out_unfreeze: |
ecdd0959 | 1405 | blk_mq_unfreeze_queue(lo->lo_queue); |
e02898b4 | 1406 | |
faf1d254 MC |
1407 | if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) && |
1408 | !(prev_lo_flags & LO_FLAGS_PARTSCAN)) { | |
e02898b4 | 1409 | lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; |
85b0a54a JK |
1410 | bdev = lo->lo_device; |
1411 | partscan = true; | |
e02898b4 | 1412 | } |
550df5fd JK |
1413 | out_unlock: |
1414 | mutex_unlock(&loop_ctl_mutex); | |
85b0a54a JK |
1415 | if (partscan) |
1416 | loop_reread_partitions(lo, bdev); | |
e02898b4 | 1417 | |
ecdd0959 | 1418 | return err; |
1da177e4 LT |
1419 | } |
1420 | ||
1421 | static int | |
1422 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) | |
1423 | { | |
b1ab5fa3 | 1424 | struct path path; |
1da177e4 | 1425 | struct kstat stat; |
2d1d4c1e | 1426 | int ret; |
1da177e4 | 1427 | |
c28445fa | 1428 | ret = mutex_lock_killable(&loop_ctl_mutex); |
4a5ce9ba JK |
1429 | if (ret) |
1430 | return ret; | |
2d1d4c1e | 1431 | if (lo->lo_state != Lo_bound) { |
310ca162 | 1432 | mutex_unlock(&loop_ctl_mutex); |
1da177e4 | 1433 | return -ENXIO; |
2d1d4c1e OS |
1434 | } |
1435 | ||
1da177e4 LT |
1436 | memset(info, 0, sizeof(*info)); |
1437 | info->lo_number = lo->lo_number; | |
1da177e4 LT |
1438 | info->lo_offset = lo->lo_offset; |
1439 | info->lo_sizelimit = lo->lo_sizelimit; | |
1440 | info->lo_flags = lo->lo_flags; | |
1441 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); | |
1442 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); | |
1443 | info->lo_encrypt_type = | |
1444 | lo->lo_encryption ? lo->lo_encryption->number : 0; | |
1445 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { | |
1446 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; | |
1447 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, | |
1448 | lo->lo_encrypt_key_size); | |
1449 | } | |
2d1d4c1e | 1450 | |
310ca162 | 1451 | /* Drop loop_ctl_mutex while we call into the filesystem. */ |
b1ab5fa3 TH |
1452 | path = lo->lo_backing_file->f_path; |
1453 | path_get(&path); | |
310ca162 | 1454 | mutex_unlock(&loop_ctl_mutex); |
b1ab5fa3 | 1455 | ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT); |
2d1d4c1e OS |
1456 | if (!ret) { |
1457 | info->lo_device = huge_encode_dev(stat.dev); | |
1458 | info->lo_inode = stat.ino; | |
1459 | info->lo_rdevice = huge_encode_dev(stat.rdev); | |
1460 | } | |
b1ab5fa3 | 1461 | path_put(&path); |
2d1d4c1e | 1462 | return ret; |
1da177e4 LT |
1463 | } |
1464 | ||
1465 | static void | |
1466 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) | |
1467 | { | |
1468 | memset(info64, 0, sizeof(*info64)); | |
1469 | info64->lo_number = info->lo_number; | |
1470 | info64->lo_device = info->lo_device; | |
1471 | info64->lo_inode = info->lo_inode; | |
1472 | info64->lo_rdevice = info->lo_rdevice; | |
1473 | info64->lo_offset = info->lo_offset; | |
1474 | info64->lo_sizelimit = 0; | |
1475 | info64->lo_encrypt_type = info->lo_encrypt_type; | |
1476 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; | |
1477 | info64->lo_flags = info->lo_flags; | |
1478 | info64->lo_init[0] = info->lo_init[0]; | |
1479 | info64->lo_init[1] = info->lo_init[1]; | |
1480 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1481 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); | |
1482 | else | |
1483 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); | |
1484 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); | |
1485 | } | |
1486 | ||
1487 | static int | |
1488 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) | |
1489 | { | |
1490 | memset(info, 0, sizeof(*info)); | |
1491 | info->lo_number = info64->lo_number; | |
1492 | info->lo_device = info64->lo_device; | |
1493 | info->lo_inode = info64->lo_inode; | |
1494 | info->lo_rdevice = info64->lo_rdevice; | |
1495 | info->lo_offset = info64->lo_offset; | |
1496 | info->lo_encrypt_type = info64->lo_encrypt_type; | |
1497 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1498 | info->lo_flags = info64->lo_flags; | |
1499 | info->lo_init[0] = info64->lo_init[0]; | |
1500 | info->lo_init[1] = info64->lo_init[1]; | |
1501 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1502 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1503 | else | |
1504 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1505 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1506 | ||
1507 | /* error in case values were truncated */ | |
1508 | if (info->lo_device != info64->lo_device || | |
1509 | info->lo_rdevice != info64->lo_rdevice || | |
1510 | info->lo_inode != info64->lo_inode || | |
1511 | info->lo_offset != info64->lo_offset) | |
1512 | return -EOVERFLOW; | |
1513 | ||
1514 | return 0; | |
1515 | } | |
1516 | ||
1517 | static int | |
1518 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) | |
1519 | { | |
1520 | struct loop_info info; | |
1521 | struct loop_info64 info64; | |
1522 | ||
1523 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) | |
1524 | return -EFAULT; | |
1525 | loop_info64_from_old(&info, &info64); | |
1526 | return loop_set_status(lo, &info64); | |
1527 | } | |
1528 | ||
1529 | static int | |
1530 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) | |
1531 | { | |
1532 | struct loop_info64 info64; | |
1533 | ||
1534 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) | |
1535 | return -EFAULT; | |
1536 | return loop_set_status(lo, &info64); | |
1537 | } | |
1538 | ||
1539 | static int | |
1540 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { | |
1541 | struct loop_info info; | |
1542 | struct loop_info64 info64; | |
bdac616d | 1543 | int err; |
1da177e4 | 1544 | |
4a5ce9ba | 1545 | if (!arg) |
bdac616d | 1546 | return -EINVAL; |
bdac616d | 1547 | err = loop_get_status(lo, &info64); |
1da177e4 LT |
1548 | if (!err) |
1549 | err = loop_info64_to_old(&info64, &info); | |
1550 | if (!err && copy_to_user(arg, &info, sizeof(info))) | |
1551 | err = -EFAULT; | |
1552 | ||
1553 | return err; | |
1554 | } | |
1555 | ||
1556 | static int | |
1557 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { | |
1558 | struct loop_info64 info64; | |
bdac616d | 1559 | int err; |
1da177e4 | 1560 | |
4a5ce9ba | 1561 | if (!arg) |
bdac616d | 1562 | return -EINVAL; |
bdac616d | 1563 | err = loop_get_status(lo, &info64); |
1da177e4 LT |
1564 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) |
1565 | err = -EFAULT; | |
1566 | ||
1567 | return err; | |
1568 | } | |
1569 | ||
51001b7d | 1570 | static int loop_set_capacity(struct loop_device *lo) |
53d66608 | 1571 | { |
0a6ed1b5 MC |
1572 | loff_t size; |
1573 | ||
53d66608 | 1574 | if (unlikely(lo->lo_state != Lo_bound)) |
7b0576a3 | 1575 | return -ENXIO; |
53d66608 | 1576 | |
0a6ed1b5 MC |
1577 | size = get_loop_size(lo, lo->lo_backing_file); |
1578 | loop_set_size(lo, size); | |
083a6a50 MC |
1579 | |
1580 | return 0; | |
53d66608 O |
1581 | } |
1582 | ||
ab1cb278 ML |
1583 | static int loop_set_dio(struct loop_device *lo, unsigned long arg) |
1584 | { | |
1585 | int error = -ENXIO; | |
1586 | if (lo->lo_state != Lo_bound) | |
1587 | goto out; | |
1588 | ||
1589 | __loop_update_dio(lo, !!arg); | |
1590 | if (lo->use_dio == !!arg) | |
1591 | return 0; | |
1592 | error = -EINVAL; | |
1593 | out: | |
1594 | return error; | |
1595 | } | |
1596 | ||
89e4fdec OS |
1597 | static int loop_set_block_size(struct loop_device *lo, unsigned long arg) |
1598 | { | |
5db470e2 JK |
1599 | int err = 0; |
1600 | ||
89e4fdec OS |
1601 | if (lo->lo_state != Lo_bound) |
1602 | return -ENXIO; | |
1603 | ||
3448914e MC |
1604 | err = loop_validate_block_size(arg); |
1605 | if (err) | |
1606 | return err; | |
89e4fdec | 1607 | |
7e81f99a MC |
1608 | if (lo->lo_queue->limits.logical_block_size == arg) |
1609 | return 0; | |
1610 | ||
1611 | sync_blockdev(lo->lo_device); | |
f4bd34b1 | 1612 | invalidate_bdev(lo->lo_device); |
5db470e2 | 1613 | |
89e4fdec OS |
1614 | blk_mq_freeze_queue(lo->lo_queue); |
1615 | ||
f4bd34b1 | 1616 | /* invalidate_bdev should have truncated all the pages */ |
7e81f99a | 1617 | if (lo->lo_device->bd_inode->i_mapping->nrpages) { |
5db470e2 JK |
1618 | err = -EAGAIN; |
1619 | pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", | |
1620 | __func__, lo->lo_number, lo->lo_file_name, | |
1621 | lo->lo_device->bd_inode->i_mapping->nrpages); | |
1622 | goto out_unfreeze; | |
1623 | } | |
1624 | ||
89e4fdec | 1625 | blk_queue_logical_block_size(lo->lo_queue, arg); |
bf093753 OS |
1626 | blk_queue_physical_block_size(lo->lo_queue, arg); |
1627 | blk_queue_io_min(lo->lo_queue, arg); | |
89e4fdec | 1628 | loop_update_dio(lo); |
5db470e2 | 1629 | out_unfreeze: |
89e4fdec OS |
1630 | blk_mq_unfreeze_queue(lo->lo_queue); |
1631 | ||
5db470e2 | 1632 | return err; |
89e4fdec OS |
1633 | } |
1634 | ||
a1316544 JK |
1635 | static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd, |
1636 | unsigned long arg) | |
1da177e4 | 1637 | { |
1da177e4 LT |
1638 | int err; |
1639 | ||
c28445fa | 1640 | err = mutex_lock_killable(&loop_ctl_mutex); |
3148ffbd | 1641 | if (err) |
a1316544 JK |
1642 | return err; |
1643 | switch (cmd) { | |
1644 | case LOOP_SET_CAPACITY: | |
1645 | err = loop_set_capacity(lo); | |
1646 | break; | |
1647 | case LOOP_SET_DIRECT_IO: | |
1648 | err = loop_set_dio(lo, arg); | |
1649 | break; | |
1650 | case LOOP_SET_BLOCK_SIZE: | |
1651 | err = loop_set_block_size(lo, arg); | |
1652 | break; | |
1653 | default: | |
1654 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; | |
1655 | } | |
1656 | mutex_unlock(&loop_ctl_mutex); | |
1657 | return err; | |
1658 | } | |
1659 | ||
1660 | static int lo_ioctl(struct block_device *bdev, fmode_t mode, | |
1661 | unsigned int cmd, unsigned long arg) | |
1662 | { | |
1663 | struct loop_device *lo = bdev->bd_disk->private_data; | |
571fae6e | 1664 | void __user *argp = (void __user *) arg; |
a1316544 | 1665 | int err; |
3148ffbd | 1666 | |
1da177e4 | 1667 | switch (cmd) { |
3448914e MC |
1668 | case LOOP_SET_FD: { |
1669 | /* | |
1670 | * Legacy case - pass in a zeroed out struct loop_config with | |
1671 | * only the file descriptor set , which corresponds with the | |
1672 | * default parameters we'd have used otherwise. | |
1673 | */ | |
1674 | struct loop_config config; | |
1675 | ||
1676 | memset(&config, 0, sizeof(config)); | |
1677 | config.fd = arg; | |
1678 | ||
1679 | return loop_configure(lo, mode, bdev, &config); | |
1680 | } | |
1681 | case LOOP_CONFIGURE: { | |
1682 | struct loop_config config; | |
1683 | ||
1684 | if (copy_from_user(&config, argp, sizeof(config))) | |
1685 | return -EFAULT; | |
1686 | ||
1687 | return loop_configure(lo, mode, bdev, &config); | |
1688 | } | |
1da177e4 | 1689 | case LOOP_CHANGE_FD: |
c3710770 | 1690 | return loop_change_fd(lo, bdev, arg); |
1da177e4 | 1691 | case LOOP_CLR_FD: |
7ccd0791 | 1692 | return loop_clr_fd(lo); |
1da177e4 | 1693 | case LOOP_SET_STATUS: |
7035b5df | 1694 | err = -EPERM; |
a1316544 | 1695 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { |
571fae6e | 1696 | err = loop_set_status_old(lo, argp); |
a1316544 | 1697 | } |
1da177e4 LT |
1698 | break; |
1699 | case LOOP_GET_STATUS: | |
571fae6e | 1700 | return loop_get_status_old(lo, argp); |
1da177e4 | 1701 | case LOOP_SET_STATUS64: |
7035b5df | 1702 | err = -EPERM; |
a1316544 | 1703 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { |
571fae6e | 1704 | err = loop_set_status64(lo, argp); |
a1316544 | 1705 | } |
1da177e4 LT |
1706 | break; |
1707 | case LOOP_GET_STATUS64: | |
571fae6e | 1708 | return loop_get_status64(lo, argp); |
a1316544 | 1709 | case LOOP_SET_CAPACITY: |
ab1cb278 | 1710 | case LOOP_SET_DIRECT_IO: |
89e4fdec | 1711 | case LOOP_SET_BLOCK_SIZE: |
a1316544 JK |
1712 | if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN)) |
1713 | return -EPERM; | |
df561f66 | 1714 | fallthrough; |
1da177e4 | 1715 | default: |
a1316544 JK |
1716 | err = lo_simple_ioctl(lo, cmd, arg); |
1717 | break; | |
1da177e4 | 1718 | } |
f028f3b2 | 1719 | |
1da177e4 LT |
1720 | return err; |
1721 | } | |
1722 | ||
863d5b82 DH |
1723 | #ifdef CONFIG_COMPAT |
1724 | struct compat_loop_info { | |
1725 | compat_int_t lo_number; /* ioctl r/o */ | |
1726 | compat_dev_t lo_device; /* ioctl r/o */ | |
1727 | compat_ulong_t lo_inode; /* ioctl r/o */ | |
1728 | compat_dev_t lo_rdevice; /* ioctl r/o */ | |
1729 | compat_int_t lo_offset; | |
1730 | compat_int_t lo_encrypt_type; | |
1731 | compat_int_t lo_encrypt_key_size; /* ioctl w/o */ | |
1732 | compat_int_t lo_flags; /* ioctl r/o */ | |
1733 | char lo_name[LO_NAME_SIZE]; | |
1734 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ | |
1735 | compat_ulong_t lo_init[2]; | |
1736 | char reserved[4]; | |
1737 | }; | |
1738 | ||
1739 | /* | |
1740 | * Transfer 32-bit compatibility structure in userspace to 64-bit loop info | |
1741 | * - noinlined to reduce stack space usage in main part of driver | |
1742 | */ | |
1743 | static noinline int | |
ba674cfc | 1744 | loop_info64_from_compat(const struct compat_loop_info __user *arg, |
863d5b82 DH |
1745 | struct loop_info64 *info64) |
1746 | { | |
1747 | struct compat_loop_info info; | |
1748 | ||
1749 | if (copy_from_user(&info, arg, sizeof(info))) | |
1750 | return -EFAULT; | |
1751 | ||
1752 | memset(info64, 0, sizeof(*info64)); | |
1753 | info64->lo_number = info.lo_number; | |
1754 | info64->lo_device = info.lo_device; | |
1755 | info64->lo_inode = info.lo_inode; | |
1756 | info64->lo_rdevice = info.lo_rdevice; | |
1757 | info64->lo_offset = info.lo_offset; | |
1758 | info64->lo_sizelimit = 0; | |
1759 | info64->lo_encrypt_type = info.lo_encrypt_type; | |
1760 | info64->lo_encrypt_key_size = info.lo_encrypt_key_size; | |
1761 | info64->lo_flags = info.lo_flags; | |
1762 | info64->lo_init[0] = info.lo_init[0]; | |
1763 | info64->lo_init[1] = info.lo_init[1]; | |
1764 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1765 | memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); | |
1766 | else | |
1767 | memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); | |
1768 | memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); | |
1769 | return 0; | |
1770 | } | |
1771 | ||
1772 | /* | |
1773 | * Transfer 64-bit loop info to 32-bit compatibility structure in userspace | |
1774 | * - noinlined to reduce stack space usage in main part of driver | |
1775 | */ | |
1776 | static noinline int | |
1777 | loop_info64_to_compat(const struct loop_info64 *info64, | |
1778 | struct compat_loop_info __user *arg) | |
1779 | { | |
1780 | struct compat_loop_info info; | |
1781 | ||
1782 | memset(&info, 0, sizeof(info)); | |
1783 | info.lo_number = info64->lo_number; | |
1784 | info.lo_device = info64->lo_device; | |
1785 | info.lo_inode = info64->lo_inode; | |
1786 | info.lo_rdevice = info64->lo_rdevice; | |
1787 | info.lo_offset = info64->lo_offset; | |
1788 | info.lo_encrypt_type = info64->lo_encrypt_type; | |
1789 | info.lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1790 | info.lo_flags = info64->lo_flags; | |
1791 | info.lo_init[0] = info64->lo_init[0]; | |
1792 | info.lo_init[1] = info64->lo_init[1]; | |
1793 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1794 | memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1795 | else | |
1796 | memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1797 | memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1798 | ||
1799 | /* error in case values were truncated */ | |
1800 | if (info.lo_device != info64->lo_device || | |
1801 | info.lo_rdevice != info64->lo_rdevice || | |
1802 | info.lo_inode != info64->lo_inode || | |
1803 | info.lo_offset != info64->lo_offset || | |
1804 | info.lo_init[0] != info64->lo_init[0] || | |
1805 | info.lo_init[1] != info64->lo_init[1]) | |
1806 | return -EOVERFLOW; | |
1807 | ||
1808 | if (copy_to_user(arg, &info, sizeof(info))) | |
1809 | return -EFAULT; | |
1810 | return 0; | |
1811 | } | |
1812 | ||
1813 | static int | |
1814 | loop_set_status_compat(struct loop_device *lo, | |
1815 | const struct compat_loop_info __user *arg) | |
1816 | { | |
1817 | struct loop_info64 info64; | |
1818 | int ret; | |
1819 | ||
1820 | ret = loop_info64_from_compat(arg, &info64); | |
1821 | if (ret < 0) | |
1822 | return ret; | |
1823 | return loop_set_status(lo, &info64); | |
1824 | } | |
1825 | ||
1826 | static int | |
1827 | loop_get_status_compat(struct loop_device *lo, | |
1828 | struct compat_loop_info __user *arg) | |
1829 | { | |
1830 | struct loop_info64 info64; | |
bdac616d | 1831 | int err; |
863d5b82 | 1832 | |
4a5ce9ba | 1833 | if (!arg) |
bdac616d | 1834 | return -EINVAL; |
bdac616d | 1835 | err = loop_get_status(lo, &info64); |
863d5b82 DH |
1836 | if (!err) |
1837 | err = loop_info64_to_compat(&info64, arg); | |
1838 | return err; | |
1839 | } | |
1840 | ||
bb214884 AV |
1841 | static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
1842 | unsigned int cmd, unsigned long arg) | |
863d5b82 | 1843 | { |
bb214884 | 1844 | struct loop_device *lo = bdev->bd_disk->private_data; |
863d5b82 DH |
1845 | int err; |
1846 | ||
863d5b82 DH |
1847 | switch(cmd) { |
1848 | case LOOP_SET_STATUS: | |
550df5fd JK |
1849 | err = loop_set_status_compat(lo, |
1850 | (const struct compat_loop_info __user *)arg); | |
863d5b82 DH |
1851 | break; |
1852 | case LOOP_GET_STATUS: | |
4a5ce9ba JK |
1853 | err = loop_get_status_compat(lo, |
1854 | (struct compat_loop_info __user *)arg); | |
863d5b82 | 1855 | break; |
53d66608 | 1856 | case LOOP_SET_CAPACITY: |
863d5b82 DH |
1857 | case LOOP_CLR_FD: |
1858 | case LOOP_GET_STATUS64: | |
1859 | case LOOP_SET_STATUS64: | |
3448914e | 1860 | case LOOP_CONFIGURE: |
863d5b82 | 1861 | arg = (unsigned long) compat_ptr(arg); |
df561f66 | 1862 | fallthrough; |
863d5b82 DH |
1863 | case LOOP_SET_FD: |
1864 | case LOOP_CHANGE_FD: | |
9fea4b39 | 1865 | case LOOP_SET_BLOCK_SIZE: |
fdbe4eee | 1866 | case LOOP_SET_DIRECT_IO: |
bb214884 | 1867 | err = lo_ioctl(bdev, mode, cmd, arg); |
863d5b82 DH |
1868 | break; |
1869 | default: | |
1870 | err = -ENOIOCTLCMD; | |
1871 | break; | |
1872 | } | |
863d5b82 DH |
1873 | return err; |
1874 | } | |
1875 | #endif | |
1876 | ||
bb214884 | 1877 | static int lo_open(struct block_device *bdev, fmode_t mode) |
1da177e4 | 1878 | { |
770fe30a | 1879 | struct loop_device *lo; |
0a42e99b | 1880 | int err; |
770fe30a | 1881 | |
0a42e99b JK |
1882 | err = mutex_lock_killable(&loop_ctl_mutex); |
1883 | if (err) | |
1884 | return err; | |
770fe30a KS |
1885 | lo = bdev->bd_disk->private_data; |
1886 | if (!lo) { | |
1887 | err = -ENXIO; | |
1888 | goto out; | |
1889 | } | |
1da177e4 | 1890 | |
f8933667 | 1891 | atomic_inc(&lo->lo_refcnt); |
770fe30a | 1892 | out: |
0a42e99b | 1893 | mutex_unlock(&loop_ctl_mutex); |
770fe30a | 1894 | return err; |
1da177e4 LT |
1895 | } |
1896 | ||
967d1dc1 | 1897 | static void lo_release(struct gendisk *disk, fmode_t mode) |
1da177e4 | 1898 | { |
967d1dc1 | 1899 | struct loop_device *lo; |
1da177e4 | 1900 | |
0a42e99b | 1901 | mutex_lock(&loop_ctl_mutex); |
967d1dc1 | 1902 | lo = disk->private_data; |
f8933667 | 1903 | if (atomic_dec_return(&lo->lo_refcnt)) |
0a42e99b | 1904 | goto out_unlock; |
14f27939 MB |
1905 | |
1906 | if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { | |
a2505b79 JK |
1907 | if (lo->lo_state != Lo_bound) |
1908 | goto out_unlock; | |
1909 | lo->lo_state = Lo_rundown; | |
7ccd0791 | 1910 | mutex_unlock(&loop_ctl_mutex); |
14f27939 MB |
1911 | /* |
1912 | * In autoclear mode, stop the loop thread | |
1913 | * and remove configuration after last close. | |
1914 | */ | |
0da03cab | 1915 | __loop_clr_fd(lo, true); |
7ccd0791 | 1916 | return; |
43cade80 | 1917 | } else if (lo->lo_state == Lo_bound) { |
14f27939 MB |
1918 | /* |
1919 | * Otherwise keep thread (if running) and config, | |
1920 | * but flush possible ongoing bios in thread. | |
1921 | */ | |
43cade80 OS |
1922 | blk_mq_freeze_queue(lo->lo_queue); |
1923 | blk_mq_unfreeze_queue(lo->lo_queue); | |
14f27939 | 1924 | } |
96c58655 | 1925 | |
0a42e99b | 1926 | out_unlock: |
310ca162 | 1927 | mutex_unlock(&loop_ctl_mutex); |
ae665016 LT |
1928 | } |
1929 | ||
83d5cde4 | 1930 | static const struct block_device_operations lo_fops = { |
1da177e4 | 1931 | .owner = THIS_MODULE, |
bb214884 AV |
1932 | .open = lo_open, |
1933 | .release = lo_release, | |
1934 | .ioctl = lo_ioctl, | |
863d5b82 | 1935 | #ifdef CONFIG_COMPAT |
bb214884 | 1936 | .compat_ioctl = lo_compat_ioctl, |
863d5b82 | 1937 | #endif |
1da177e4 LT |
1938 | }; |
1939 | ||
1940 | /* | |
1941 | * And now the modules code and kernel interface. | |
1942 | */ | |
73285082 | 1943 | static int max_loop; |
5657a819 | 1944 | module_param(max_loop, int, 0444); |
a47653fc | 1945 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
5657a819 | 1946 | module_param(max_part, int, 0444); |
476a4813 | 1947 | MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
1da177e4 LT |
1948 | MODULE_LICENSE("GPL"); |
1949 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); | |
1950 | ||
1951 | int loop_register_transfer(struct loop_func_table *funcs) | |
1952 | { | |
1953 | unsigned int n = funcs->number; | |
1954 | ||
1955 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) | |
1956 | return -EINVAL; | |
1957 | xfer_funcs[n] = funcs; | |
1958 | return 0; | |
1959 | } | |
1960 | ||
34dd82af KS |
1961 | static int unregister_transfer_cb(int id, void *ptr, void *data) |
1962 | { | |
1963 | struct loop_device *lo = ptr; | |
1964 | struct loop_func_table *xfer = data; | |
1965 | ||
310ca162 | 1966 | mutex_lock(&loop_ctl_mutex); |
34dd82af KS |
1967 | if (lo->lo_encryption == xfer) |
1968 | loop_release_xfer(lo); | |
310ca162 | 1969 | mutex_unlock(&loop_ctl_mutex); |
34dd82af KS |
1970 | return 0; |
1971 | } | |
1972 | ||
1da177e4 LT |
1973 | int loop_unregister_transfer(int number) |
1974 | { | |
1975 | unsigned int n = number; | |
1da177e4 LT |
1976 | struct loop_func_table *xfer; |
1977 | ||
1978 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) | |
1979 | return -EINVAL; | |
1980 | ||
1981 | xfer_funcs[n] = NULL; | |
34dd82af | 1982 | idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer); |
1da177e4 LT |
1983 | return 0; |
1984 | } | |
1985 | ||
1986 | EXPORT_SYMBOL(loop_register_transfer); | |
1987 | EXPORT_SYMBOL(loop_unregister_transfer); | |
1988 | ||
fc17b653 | 1989 | static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, |
b5dd2f60 ML |
1990 | const struct blk_mq_queue_data *bd) |
1991 | { | |
1894e916 JA |
1992 | struct request *rq = bd->rq; |
1993 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
1994 | struct loop_device *lo = rq->q->queuedata; | |
b5dd2f60 | 1995 | |
1894e916 | 1996 | blk_mq_start_request(rq); |
b5dd2f60 | 1997 | |
f4aa4c7b | 1998 | if (lo->lo_state != Lo_bound) |
fc17b653 | 1999 | return BLK_STS_IOERR; |
f4aa4c7b | 2000 | |
1894e916 | 2001 | switch (req_op(rq)) { |
f0225cac CH |
2002 | case REQ_OP_FLUSH: |
2003 | case REQ_OP_DISCARD: | |
19372e27 | 2004 | case REQ_OP_WRITE_ZEROES: |
bc07c10a | 2005 | cmd->use_aio = false; |
f0225cac CH |
2006 | break; |
2007 | default: | |
2008 | cmd->use_aio = lo->use_dio; | |
2009 | break; | |
2010 | } | |
bc07c10a | 2011 | |
d4478e92 | 2012 | /* always use the first bio's css */ |
0b508bc9 | 2013 | #ifdef CONFIG_BLK_CGROUP |
db6638d7 DZ |
2014 | if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { |
2015 | cmd->css = &bio_blkcg(rq->bio)->css; | |
d4478e92 SL |
2016 | css_get(cmd->css); |
2017 | } else | |
2018 | #endif | |
2019 | cmd->css = NULL; | |
3989144f | 2020 | kthread_queue_work(&lo->worker, &cmd->work); |
b5dd2f60 | 2021 | |
fc17b653 | 2022 | return BLK_STS_OK; |
b5dd2f60 ML |
2023 | } |
2024 | ||
2025 | static void loop_handle_cmd(struct loop_cmd *cmd) | |
2026 | { | |
1894e916 JA |
2027 | struct request *rq = blk_mq_rq_from_pdu(cmd); |
2028 | const bool write = op_is_write(req_op(rq)); | |
2029 | struct loop_device *lo = rq->q->queuedata; | |
f4829a9b | 2030 | int ret = 0; |
b5dd2f60 | 2031 | |
f4829a9b CH |
2032 | if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { |
2033 | ret = -EIO; | |
b5dd2f60 | 2034 | goto failed; |
f4829a9b | 2035 | } |
b5dd2f60 | 2036 | |
1894e916 | 2037 | ret = do_req_filebacked(lo, rq); |
b5dd2f60 | 2038 | failed: |
bc07c10a | 2039 | /* complete non-aio request */ |
fe2cb290 | 2040 | if (!cmd->use_aio || ret) { |
8cd55087 EG |
2041 | if (ret == -EOPNOTSUPP) |
2042 | cmd->ret = ret; | |
2043 | else | |
2044 | cmd->ret = ret ? -EIO : 0; | |
15f73f5b CH |
2045 | if (likely(!blk_should_fake_timeout(rq->q))) |
2046 | blk_mq_complete_request(rq); | |
fe2cb290 | 2047 | } |
b5dd2f60 ML |
2048 | } |
2049 | ||
e03a3d7a | 2050 | static void loop_queue_work(struct kthread_work *work) |
b5dd2f60 ML |
2051 | { |
2052 | struct loop_cmd *cmd = | |
e03a3d7a | 2053 | container_of(work, struct loop_cmd, work); |
b5dd2f60 ML |
2054 | |
2055 | loop_handle_cmd(cmd); | |
2056 | } | |
2057 | ||
d6296d39 CH |
2058 | static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq, |
2059 | unsigned int hctx_idx, unsigned int numa_node) | |
b5dd2f60 ML |
2060 | { |
2061 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
2062 | ||
3989144f | 2063 | kthread_init_work(&cmd->work, loop_queue_work); |
b5dd2f60 ML |
2064 | return 0; |
2065 | } | |
2066 | ||
f363b089 | 2067 | static const struct blk_mq_ops loop_mq_ops = { |
b5dd2f60 | 2068 | .queue_rq = loop_queue_rq, |
b5dd2f60 | 2069 | .init_request = loop_init_request, |
fe2cb290 | 2070 | .complete = lo_complete_rq, |
b5dd2f60 ML |
2071 | }; |
2072 | ||
34dd82af | 2073 | static int loop_add(struct loop_device **l, int i) |
73285082 KC |
2074 | { |
2075 | struct loop_device *lo; | |
2076 | struct gendisk *disk; | |
34dd82af | 2077 | int err; |
73285082 | 2078 | |
68d740d7 | 2079 | err = -ENOMEM; |
73285082 | 2080 | lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
68d740d7 | 2081 | if (!lo) |
73285082 | 2082 | goto out; |
34dd82af | 2083 | |
ef7e7c82 MP |
2084 | lo->lo_state = Lo_unbound; |
2085 | ||
c718aa65 | 2086 | /* allocate id, if @id >= 0, we're requesting that specific id */ |
34dd82af | 2087 | if (i >= 0) { |
c718aa65 TH |
2088 | err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL); |
2089 | if (err == -ENOSPC) | |
34dd82af | 2090 | err = -EEXIST; |
34dd82af | 2091 | } else { |
c718aa65 | 2092 | err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL); |
34dd82af KS |
2093 | } |
2094 | if (err < 0) | |
2095 | goto out_free_dev; | |
c718aa65 | 2096 | i = err; |
73285082 | 2097 | |
183cfb57 | 2098 | err = -ENOMEM; |
b5dd2f60 ML |
2099 | lo->tag_set.ops = &loop_mq_ops; |
2100 | lo->tag_set.nr_hw_queues = 1; | |
2101 | lo->tag_set.queue_depth = 128; | |
2102 | lo->tag_set.numa_node = NUMA_NO_NODE; | |
2103 | lo->tag_set.cmd_size = sizeof(struct loop_cmd); | |
bf0beec0 | 2104 | lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING; |
b5dd2f60 ML |
2105 | lo->tag_set.driver_data = lo; |
2106 | ||
2107 | err = blk_mq_alloc_tag_set(&lo->tag_set); | |
2108 | if (err) | |
3ec981e3 | 2109 | goto out_free_idr; |
73285082 | 2110 | |
b5dd2f60 | 2111 | lo->lo_queue = blk_mq_init_queue(&lo->tag_set); |
38a3499f | 2112 | if (IS_ERR(lo->lo_queue)) { |
b5dd2f60 ML |
2113 | err = PTR_ERR(lo->lo_queue); |
2114 | goto out_cleanup_tags; | |
2115 | } | |
ef7e7c82 MP |
2116 | lo->lo_queue->queuedata = lo; |
2117 | ||
54bb0ade | 2118 | blk_queue_max_hw_sectors(lo->lo_queue, BLK_DEF_MAX_SECTORS); |
40326d8a | 2119 | |
5b5e20f4 | 2120 | /* |
40326d8a SL |
2121 | * By default, we do buffer IO, so it doesn't make sense to enable |
2122 | * merge because the I/O submitted to backing file is handled page by | |
2123 | * page. For directio mode, merge does help to dispatch bigger request | |
2124 | * to underlayer disk. We will enable merge once directio is enabled. | |
5b5e20f4 | 2125 | */ |
8b904b5b | 2126 | blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
5b5e20f4 | 2127 | |
7a649737 | 2128 | err = -ENOMEM; |
476a4813 | 2129 | disk = lo->lo_disk = alloc_disk(1 << part_shift); |
73285082 KC |
2130 | if (!disk) |
2131 | goto out_free_queue; | |
2132 | ||
e03c8dd1 KS |
2133 | /* |
2134 | * Disable partition scanning by default. The in-kernel partition | |
2135 | * scanning can be requested individually per-device during its | |
2136 | * setup. Userspace can always add and remove partitions from all | |
2137 | * devices. The needed partition minors are allocated from the | |
2138 | * extended minor space, the main loop device numbers will continue | |
2139 | * to match the loop minors, regardless of the number of partitions | |
2140 | * used. | |
2141 | * | |
2142 | * If max_part is given, partition scanning is globally enabled for | |
2143 | * all loop devices. The minors for the main loop devices will be | |
2144 | * multiples of max_part. | |
2145 | * | |
2146 | * Note: Global-for-all-devices, set-only-at-init, read-only module | |
2147 | * parameteters like 'max_loop' and 'max_part' make things needlessly | |
2148 | * complicated, are too static, inflexible and may surprise | |
2149 | * userspace tools. Parameters like this in general should be avoided. | |
2150 | */ | |
2151 | if (!part_shift) | |
2152 | disk->flags |= GENHD_FL_NO_PART_SCAN; | |
2153 | disk->flags |= GENHD_FL_EXT_DEVT; | |
f8933667 | 2154 | atomic_set(&lo->lo_refcnt, 0); |
73285082 | 2155 | lo->lo_number = i; |
73285082 KC |
2156 | spin_lock_init(&lo->lo_lock); |
2157 | disk->major = LOOP_MAJOR; | |
476a4813 | 2158 | disk->first_minor = i << part_shift; |
73285082 KC |
2159 | disk->fops = &lo_fops; |
2160 | disk->private_data = lo; | |
2161 | disk->queue = lo->lo_queue; | |
2162 | sprintf(disk->disk_name, "loop%d", i); | |
34dd82af KS |
2163 | add_disk(disk); |
2164 | *l = lo; | |
2165 | return lo->lo_number; | |
73285082 KC |
2166 | |
2167 | out_free_queue: | |
2168 | blk_cleanup_queue(lo->lo_queue); | |
b5dd2f60 ML |
2169 | out_cleanup_tags: |
2170 | blk_mq_free_tag_set(&lo->tag_set); | |
3ec981e3 MP |
2171 | out_free_idr: |
2172 | idr_remove(&loop_index_idr, i); | |
73285082 KC |
2173 | out_free_dev: |
2174 | kfree(lo); | |
2175 | out: | |
34dd82af | 2176 | return err; |
73285082 KC |
2177 | } |
2178 | ||
34dd82af | 2179 | static void loop_remove(struct loop_device *lo) |
1da177e4 | 2180 | { |
6cd18e71 | 2181 | del_gendisk(lo->lo_disk); |
0fa8ebdd | 2182 | blk_cleanup_queue(lo->lo_queue); |
b5dd2f60 | 2183 | blk_mq_free_tag_set(&lo->tag_set); |
73285082 | 2184 | put_disk(lo->lo_disk); |
73285082 KC |
2185 | kfree(lo); |
2186 | } | |
1da177e4 | 2187 | |
770fe30a KS |
2188 | static int find_free_cb(int id, void *ptr, void *data) |
2189 | { | |
2190 | struct loop_device *lo = ptr; | |
2191 | struct loop_device **l = data; | |
2192 | ||
2193 | if (lo->lo_state == Lo_unbound) { | |
2194 | *l = lo; | |
2195 | return 1; | |
2196 | } | |
2197 | return 0; | |
2198 | } | |
2199 | ||
34dd82af | 2200 | static int loop_lookup(struct loop_device **l, int i) |
a47653fc KC |
2201 | { |
2202 | struct loop_device *lo; | |
34dd82af | 2203 | int ret = -ENODEV; |
a47653fc | 2204 | |
770fe30a KS |
2205 | if (i < 0) { |
2206 | int err; | |
2207 | ||
2208 | err = idr_for_each(&loop_index_idr, &find_free_cb, &lo); | |
2209 | if (err == 1) { | |
2210 | *l = lo; | |
2211 | ret = lo->lo_number; | |
2212 | } | |
2213 | goto out; | |
a47653fc KC |
2214 | } |
2215 | ||
770fe30a | 2216 | /* lookup and return a specific i */ |
34dd82af | 2217 | lo = idr_find(&loop_index_idr, i); |
a47653fc | 2218 | if (lo) { |
34dd82af KS |
2219 | *l = lo; |
2220 | ret = lo->lo_number; | |
a47653fc | 2221 | } |
770fe30a | 2222 | out: |
34dd82af | 2223 | return ret; |
a47653fc KC |
2224 | } |
2225 | ||
8410d38c | 2226 | static void loop_probe(dev_t dev) |
73285082 | 2227 | { |
8410d38c | 2228 | int idx = MINOR(dev) >> part_shift; |
705962cc | 2229 | struct loop_device *lo; |
8410d38c CH |
2230 | |
2231 | if (max_loop && idx >= max_loop) | |
2232 | return; | |
73285082 | 2233 | |
0a42e99b | 2234 | mutex_lock(&loop_ctl_mutex); |
8410d38c CH |
2235 | if (loop_lookup(&lo, idx) < 0) |
2236 | loop_add(&lo, idx); | |
0a42e99b | 2237 | mutex_unlock(&loop_ctl_mutex); |
73285082 KC |
2238 | } |
2239 | ||
770fe30a KS |
2240 | static long loop_control_ioctl(struct file *file, unsigned int cmd, |
2241 | unsigned long parm) | |
2242 | { | |
2243 | struct loop_device *lo; | |
0a42e99b | 2244 | int ret; |
770fe30a | 2245 | |
0a42e99b JK |
2246 | ret = mutex_lock_killable(&loop_ctl_mutex); |
2247 | if (ret) | |
2248 | return ret; | |
2249 | ||
2250 | ret = -ENOSYS; | |
770fe30a KS |
2251 | switch (cmd) { |
2252 | case LOOP_CTL_ADD: | |
2253 | ret = loop_lookup(&lo, parm); | |
2254 | if (ret >= 0) { | |
2255 | ret = -EEXIST; | |
2256 | break; | |
2257 | } | |
2258 | ret = loop_add(&lo, parm); | |
2259 | break; | |
2260 | case LOOP_CTL_REMOVE: | |
2261 | ret = loop_lookup(&lo, parm); | |
2262 | if (ret < 0) | |
2263 | break; | |
770fe30a KS |
2264 | if (lo->lo_state != Lo_unbound) { |
2265 | ret = -EBUSY; | |
770fe30a KS |
2266 | break; |
2267 | } | |
f8933667 | 2268 | if (atomic_read(&lo->lo_refcnt) > 0) { |
770fe30a | 2269 | ret = -EBUSY; |
770fe30a KS |
2270 | break; |
2271 | } | |
2272 | lo->lo_disk->private_data = NULL; | |
770fe30a KS |
2273 | idr_remove(&loop_index_idr, lo->lo_number); |
2274 | loop_remove(lo); | |
2275 | break; | |
2276 | case LOOP_CTL_GET_FREE: | |
2277 | ret = loop_lookup(&lo, -1); | |
2278 | if (ret >= 0) | |
2279 | break; | |
2280 | ret = loop_add(&lo, -1); | |
2281 | } | |
0a42e99b | 2282 | mutex_unlock(&loop_ctl_mutex); |
770fe30a KS |
2283 | |
2284 | return ret; | |
2285 | } | |
2286 | ||
2287 | static const struct file_operations loop_ctl_fops = { | |
2288 | .open = nonseekable_open, | |
2289 | .unlocked_ioctl = loop_control_ioctl, | |
2290 | .compat_ioctl = loop_control_ioctl, | |
2291 | .owner = THIS_MODULE, | |
2292 | .llseek = noop_llseek, | |
2293 | }; | |
2294 | ||
2295 | static struct miscdevice loop_misc = { | |
2296 | .minor = LOOP_CTRL_MINOR, | |
2297 | .name = "loop-control", | |
2298 | .fops = &loop_ctl_fops, | |
2299 | }; | |
2300 | ||
2301 | MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR); | |
2302 | MODULE_ALIAS("devname:loop-control"); | |
2303 | ||
73285082 KC |
2304 | static int __init loop_init(void) |
2305 | { | |
a47653fc KC |
2306 | int i, nr; |
2307 | unsigned long range; | |
34dd82af | 2308 | struct loop_device *lo; |
770fe30a | 2309 | int err; |
a47653fc | 2310 | |
476a4813 | 2311 | part_shift = 0; |
ac04fee0 | 2312 | if (max_part > 0) { |
476a4813 LV |
2313 | part_shift = fls(max_part); |
2314 | ||
ac04fee0 NK |
2315 | /* |
2316 | * Adjust max_part according to part_shift as it is exported | |
2317 | * to user space so that user can decide correct minor number | |
2318 | * if [s]he want to create more devices. | |
2319 | * | |
2320 | * Note that -1 is required because partition 0 is reserved | |
2321 | * for the whole disk. | |
2322 | */ | |
2323 | max_part = (1UL << part_shift) - 1; | |
2324 | } | |
2325 | ||
b1a66504 GC |
2326 | if ((1UL << part_shift) > DISK_MAX_PARTS) { |
2327 | err = -EINVAL; | |
a8c1d064 | 2328 | goto err_out; |
b1a66504 | 2329 | } |
78f4bb36 | 2330 | |
b1a66504 GC |
2331 | if (max_loop > 1UL << (MINORBITS - part_shift)) { |
2332 | err = -EINVAL; | |
a8c1d064 | 2333 | goto err_out; |
b1a66504 | 2334 | } |
1da177e4 | 2335 | |
d134b00b KS |
2336 | /* |
2337 | * If max_loop is specified, create that many devices upfront. | |
2338 | * This also becomes a hard limit. If max_loop is not specified, | |
2339 | * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module | |
2340 | * init time. Loop devices can be requested on-demand with the | |
2341 | * /dev/loop-control interface, or be instantiated by accessing | |
2342 | * a 'dead' device node. | |
2343 | */ | |
73285082 | 2344 | if (max_loop) { |
a47653fc | 2345 | nr = max_loop; |
a1c15c59 | 2346 | range = max_loop << part_shift; |
a47653fc | 2347 | } else { |
d134b00b | 2348 | nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; |
a1c15c59 | 2349 | range = 1UL << MINORBITS; |
a47653fc KC |
2350 | } |
2351 | ||
a8c1d064 AV |
2352 | err = misc_register(&loop_misc); |
2353 | if (err < 0) | |
2354 | goto err_out; | |
2355 | ||
2356 | ||
8410d38c | 2357 | if (__register_blkdev(LOOP_MAJOR, "loop", loop_probe)) { |
b1a66504 GC |
2358 | err = -EIO; |
2359 | goto misc_out; | |
2360 | } | |
1da177e4 | 2361 | |
d134b00b | 2362 | /* pre-create number of devices given by config or max_loop */ |
0a42e99b | 2363 | mutex_lock(&loop_ctl_mutex); |
34dd82af KS |
2364 | for (i = 0; i < nr; i++) |
2365 | loop_add(&lo, i); | |
0a42e99b | 2366 | mutex_unlock(&loop_ctl_mutex); |
34dd82af | 2367 | |
73285082 | 2368 | printk(KERN_INFO "loop: module loaded\n"); |
1da177e4 | 2369 | return 0; |
b1a66504 GC |
2370 | |
2371 | misc_out: | |
2372 | misc_deregister(&loop_misc); | |
a8c1d064 | 2373 | err_out: |
b1a66504 | 2374 | return err; |
34dd82af | 2375 | } |
a47653fc | 2376 | |
34dd82af KS |
2377 | static int loop_exit_cb(int id, void *ptr, void *data) |
2378 | { | |
2379 | struct loop_device *lo = ptr; | |
a47653fc | 2380 | |
34dd82af KS |
2381 | loop_remove(lo); |
2382 | return 0; | |
1da177e4 LT |
2383 | } |
2384 | ||
73285082 | 2385 | static void __exit loop_exit(void) |
1da177e4 | 2386 | { |
200f9337 LC |
2387 | mutex_lock(&loop_ctl_mutex); |
2388 | ||
34dd82af | 2389 | idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); |
34dd82af | 2390 | idr_destroy(&loop_index_idr); |
73285082 | 2391 | |
00d59405 | 2392 | unregister_blkdev(LOOP_MAJOR, "loop"); |
770fe30a KS |
2393 | |
2394 | misc_deregister(&loop_misc); | |
200f9337 LC |
2395 | |
2396 | mutex_unlock(&loop_ctl_mutex); | |
1da177e4 LT |
2397 | } |
2398 | ||
2399 | module_init(loop_init); | |
2400 | module_exit(loop_exit); | |
2401 | ||
2402 | #ifndef MODULE | |
2403 | static int __init max_loop_setup(char *str) | |
2404 | { | |
2405 | max_loop = simple_strtol(str, NULL, 0); | |
2406 | return 1; | |
2407 | } | |
2408 | ||
2409 | __setup("max_loop=", max_loop_setup); | |
2410 | #endif |