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Commit | Line | Data |
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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 | */ | |
217 | blk_mq_freeze_queue(lo->lo_queue); | |
218 | lo->use_dio = use_dio; | |
40326d8a | 219 | if (use_dio) { |
8b904b5b | 220 | blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
2e5ab5f3 | 221 | lo->lo_flags |= LO_FLAGS_DIRECT_IO; |
40326d8a | 222 | } else { |
8b904b5b | 223 | blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
2e5ab5f3 | 224 | lo->lo_flags &= ~LO_FLAGS_DIRECT_IO; |
40326d8a | 225 | } |
2e5ab5f3 ML |
226 | blk_mq_unfreeze_queue(lo->lo_queue); |
227 | } | |
228 | ||
1da177e4 | 229 | static int |
1e6ec9ea | 230 | figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) |
1da177e4 | 231 | { |
7035b5df | 232 | loff_t size = get_size(offset, sizelimit, lo->lo_backing_file); |
1da177e4 | 233 | sector_t x = (sector_t)size; |
7b0576a3 | 234 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
235 | |
236 | if (unlikely((loff_t)x != size)) | |
237 | return -EFBIG; | |
7035b5df DM |
238 | if (lo->lo_offset != offset) |
239 | lo->lo_offset = offset; | |
240 | if (lo->lo_sizelimit != sizelimit) | |
241 | lo->lo_sizelimit = sizelimit; | |
73285082 | 242 | set_capacity(lo->lo_disk, x); |
7b0576a3 GC |
243 | bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9); |
244 | /* let user-space know about the new size */ | |
245 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
7035b5df | 246 | return 0; |
1da177e4 LT |
247 | } |
248 | ||
249 | static inline int | |
250 | lo_do_transfer(struct loop_device *lo, int cmd, | |
251 | struct page *rpage, unsigned roffs, | |
252 | struct page *lpage, unsigned loffs, | |
253 | int size, sector_t rblock) | |
254 | { | |
aa4d8616 CH |
255 | int ret; |
256 | ||
257 | ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); | |
258 | if (likely(!ret)) | |
1da177e4 LT |
259 | return 0; |
260 | ||
aa4d8616 CH |
261 | printk_ratelimited(KERN_ERR |
262 | "loop: Transfer error at byte offset %llu, length %i.\n", | |
263 | (unsigned long long)rblock << 9, size); | |
264 | return ret; | |
1da177e4 LT |
265 | } |
266 | ||
81ba6abd ML |
267 | static inline void loop_iov_iter_bvec(struct iov_iter *i, |
268 | unsigned int direction, const struct bio_vec *bvec, | |
269 | unsigned long nr_segs, size_t count) | |
270 | { | |
271 | iov_iter_bvec(i, direction, bvec, nr_segs, count); | |
272 | i->type |= ITER_BVEC_FLAG_NO_REF; | |
273 | } | |
274 | ||
aa4d8616 | 275 | static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) |
1da177e4 | 276 | { |
aa4d8616 | 277 | struct iov_iter i; |
1da177e4 | 278 | ssize_t bw; |
283e7e5d | 279 | |
81ba6abd | 280 | loop_iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len); |
1da177e4 | 281 | |
03d95eb2 | 282 | file_start_write(file); |
abbb6589 | 283 | bw = vfs_iter_write(file, &i, ppos, 0); |
03d95eb2 | 284 | file_end_write(file); |
aa4d8616 CH |
285 | |
286 | if (likely(bw == bvec->bv_len)) | |
1da177e4 | 287 | return 0; |
aa4d8616 CH |
288 | |
289 | printk_ratelimited(KERN_ERR | |
290 | "loop: Write error at byte offset %llu, length %i.\n", | |
291 | (unsigned long long)*ppos, bvec->bv_len); | |
1da177e4 LT |
292 | if (bw >= 0) |
293 | bw = -EIO; | |
294 | return bw; | |
295 | } | |
296 | ||
aa4d8616 CH |
297 | static int lo_write_simple(struct loop_device *lo, struct request *rq, |
298 | loff_t pos) | |
1da177e4 | 299 | { |
aa4d8616 CH |
300 | struct bio_vec bvec; |
301 | struct req_iterator iter; | |
302 | int ret = 0; | |
303 | ||
304 | rq_for_each_segment(bvec, rq, iter) { | |
305 | ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos); | |
306 | if (ret < 0) | |
307 | break; | |
308 | cond_resched(); | |
309 | } | |
310 | ||
311 | return ret; | |
1da177e4 LT |
312 | } |
313 | ||
aa4d8616 | 314 | /* |
456be148 CH |
315 | * This is the slow, transforming version that needs to double buffer the |
316 | * data as it cannot do the transformations in place without having direct | |
317 | * access to the destination pages of the backing file. | |
1da177e4 | 318 | */ |
aa4d8616 CH |
319 | static int lo_write_transfer(struct loop_device *lo, struct request *rq, |
320 | loff_t pos) | |
1da177e4 | 321 | { |
aa4d8616 | 322 | struct bio_vec bvec, b; |
30112013 | 323 | struct req_iterator iter; |
aa4d8616 | 324 | struct page *page; |
7988613b | 325 | int ret = 0; |
1da177e4 | 326 | |
aa4d8616 CH |
327 | page = alloc_page(GFP_NOIO); |
328 | if (unlikely(!page)) | |
329 | return -ENOMEM; | |
456be148 | 330 | |
30112013 | 331 | rq_for_each_segment(bvec, rq, iter) { |
aa4d8616 CH |
332 | ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page, |
333 | bvec.bv_offset, bvec.bv_len, pos >> 9); | |
334 | if (unlikely(ret)) | |
335 | break; | |
336 | ||
337 | b.bv_page = page; | |
338 | b.bv_offset = 0; | |
339 | b.bv_len = bvec.bv_len; | |
340 | ret = lo_write_bvec(lo->lo_backing_file, &b, &pos); | |
1da177e4 LT |
341 | if (ret < 0) |
342 | break; | |
1da177e4 | 343 | } |
aa4d8616 CH |
344 | |
345 | __free_page(page); | |
1da177e4 | 346 | return ret; |
1da177e4 LT |
347 | } |
348 | ||
aa4d8616 CH |
349 | static int lo_read_simple(struct loop_device *lo, struct request *rq, |
350 | loff_t pos) | |
1da177e4 | 351 | { |
aa4d8616 CH |
352 | struct bio_vec bvec; |
353 | struct req_iterator iter; | |
354 | struct iov_iter i; | |
355 | ssize_t len; | |
1da177e4 | 356 | |
aa4d8616 | 357 | rq_for_each_segment(bvec, rq, iter) { |
81ba6abd | 358 | loop_iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len); |
18e9710e | 359 | len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); |
aa4d8616 CH |
360 | if (len < 0) |
361 | return len; | |
1da177e4 | 362 | |
aa4d8616 | 363 | flush_dcache_page(bvec.bv_page); |
fd582140 | 364 | |
aa4d8616 CH |
365 | if (len != bvec.bv_len) { |
366 | struct bio *bio; | |
1da177e4 | 367 | |
aa4d8616 CH |
368 | __rq_for_each_bio(bio, rq) |
369 | zero_fill_bio(bio); | |
370 | break; | |
371 | } | |
372 | cond_resched(); | |
373 | } | |
374 | ||
375 | return 0; | |
fd582140 JA |
376 | } |
377 | ||
aa4d8616 CH |
378 | static int lo_read_transfer(struct loop_device *lo, struct request *rq, |
379 | loff_t pos) | |
1da177e4 | 380 | { |
aa4d8616 CH |
381 | struct bio_vec bvec, b; |
382 | struct req_iterator iter; | |
383 | struct iov_iter i; | |
384 | struct page *page; | |
385 | ssize_t len; | |
386 | int ret = 0; | |
1da177e4 | 387 | |
aa4d8616 CH |
388 | page = alloc_page(GFP_NOIO); |
389 | if (unlikely(!page)) | |
390 | return -ENOMEM; | |
fd582140 | 391 | |
aa4d8616 CH |
392 | rq_for_each_segment(bvec, rq, iter) { |
393 | loff_t offset = pos; | |
fd582140 | 394 | |
aa4d8616 CH |
395 | b.bv_page = page; |
396 | b.bv_offset = 0; | |
397 | b.bv_len = bvec.bv_len; | |
fd582140 | 398 | |
81ba6abd | 399 | loop_iov_iter_bvec(&i, READ, &b, 1, b.bv_len); |
18e9710e | 400 | len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); |
aa4d8616 CH |
401 | if (len < 0) { |
402 | ret = len; | |
403 | goto out_free_page; | |
404 | } | |
1da177e4 | 405 | |
aa4d8616 CH |
406 | ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page, |
407 | bvec.bv_offset, len, offset >> 9); | |
408 | if (ret) | |
409 | goto out_free_page; | |
1da177e4 | 410 | |
aa4d8616 | 411 | flush_dcache_page(bvec.bv_page); |
306df071 | 412 | |
aa4d8616 | 413 | if (len != bvec.bv_len) { |
30112013 ML |
414 | struct bio *bio; |
415 | ||
416 | __rq_for_each_bio(bio, rq) | |
417 | zero_fill_bio(bio); | |
1da177e4 | 418 | break; |
306df071 | 419 | } |
1da177e4 | 420 | } |
aa4d8616 CH |
421 | |
422 | ret = 0; | |
423 | out_free_page: | |
424 | __free_page(page); | |
425 | return ret; | |
1da177e4 LT |
426 | } |
427 | ||
cf655d95 ML |
428 | static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos) |
429 | { | |
430 | /* | |
431 | * We use punch hole to reclaim the free space used by the | |
432 | * image a.k.a. discard. However we do not support discard if | |
433 | * encryption is enabled, because it may give an attacker | |
434 | * useful information. | |
435 | */ | |
436 | struct file *file = lo->lo_backing_file; | |
437 | int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE; | |
438 | int ret; | |
439 | ||
440 | if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { | |
441 | ret = -EOPNOTSUPP; | |
442 | goto out; | |
443 | } | |
444 | ||
445 | ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); | |
446 | if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) | |
447 | ret = -EIO; | |
448 | out: | |
449 | return ret; | |
450 | } | |
451 | ||
452 | static int lo_req_flush(struct loop_device *lo, struct request *rq) | |
453 | { | |
454 | struct file *file = lo->lo_backing_file; | |
455 | int ret = vfs_fsync(file, 0); | |
456 | if (unlikely(ret && ret != -EINVAL)) | |
457 | ret = -EIO; | |
458 | ||
459 | return ret; | |
460 | } | |
461 | ||
fe2cb290 | 462 | static void lo_complete_rq(struct request *rq) |
bc07c10a | 463 | { |
fe2cb290 | 464 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); |
f9de14bc | 465 | blk_status_t ret = BLK_STS_OK; |
bc07c10a | 466 | |
f9de14bc JA |
467 | if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || |
468 | req_op(rq) != REQ_OP_READ) { | |
469 | if (cmd->ret < 0) | |
470 | ret = BLK_STS_IOERR; | |
471 | goto end_io; | |
bc07c10a | 472 | } |
fe2cb290 | 473 | |
f9de14bc JA |
474 | /* |
475 | * Short READ - if we got some data, advance our request and | |
476 | * retry it. If we got no data, end the rest with EIO. | |
477 | */ | |
478 | if (cmd->ret) { | |
479 | blk_update_request(rq, BLK_STS_OK, cmd->ret); | |
480 | cmd->ret = 0; | |
481 | blk_mq_requeue_request(rq, true); | |
482 | } else { | |
483 | if (cmd->use_aio) { | |
484 | struct bio *bio = rq->bio; | |
485 | ||
486 | while (bio) { | |
487 | zero_fill_bio(bio); | |
488 | bio = bio->bi_next; | |
489 | } | |
490 | } | |
491 | ret = BLK_STS_IOERR; | |
492 | end_io: | |
493 | blk_mq_end_request(rq, ret); | |
494 | } | |
bc07c10a ML |
495 | } |
496 | ||
92d77332 SL |
497 | static void lo_rw_aio_do_completion(struct loop_cmd *cmd) |
498 | { | |
1894e916 JA |
499 | struct request *rq = blk_mq_rq_from_pdu(cmd); |
500 | ||
92d77332 SL |
501 | if (!atomic_dec_and_test(&cmd->ref)) |
502 | return; | |
503 | kfree(cmd->bvec); | |
504 | cmd->bvec = NULL; | |
1894e916 | 505 | blk_mq_complete_request(rq); |
92d77332 SL |
506 | } |
507 | ||
bc07c10a ML |
508 | static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) |
509 | { | |
510 | struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); | |
bc07c10a | 511 | |
d4478e92 SL |
512 | if (cmd->css) |
513 | css_put(cmd->css); | |
fe2cb290 | 514 | cmd->ret = ret; |
92d77332 | 515 | lo_rw_aio_do_completion(cmd); |
bc07c10a ML |
516 | } |
517 | ||
518 | static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, | |
519 | loff_t pos, bool rw) | |
520 | { | |
521 | struct iov_iter iter; | |
86af5952 | 522 | struct req_iterator rq_iter; |
bc07c10a | 523 | struct bio_vec *bvec; |
1894e916 | 524 | struct request *rq = blk_mq_rq_from_pdu(cmd); |
40326d8a | 525 | struct bio *bio = rq->bio; |
bc07c10a | 526 | struct file *file = lo->lo_backing_file; |
86af5952 | 527 | struct bio_vec tmp; |
40326d8a | 528 | unsigned int offset; |
86af5952 | 529 | int nr_bvec = 0; |
bc07c10a ML |
530 | int ret; |
531 | ||
86af5952 ML |
532 | rq_for_each_bvec(tmp, rq, rq_iter) |
533 | nr_bvec++; | |
534 | ||
40326d8a | 535 | if (rq->bio != rq->biotail) { |
40326d8a | 536 | |
86af5952 | 537 | bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), |
6da2ec56 | 538 | GFP_NOIO); |
40326d8a SL |
539 | if (!bvec) |
540 | return -EIO; | |
541 | cmd->bvec = bvec; | |
542 | ||
543 | /* | |
544 | * The bios of the request may be started from the middle of | |
545 | * the 'bvec' because of bio splitting, so we can't directly | |
86af5952 | 546 | * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec |
40326d8a SL |
547 | * API will take care of all details for us. |
548 | */ | |
86af5952 | 549 | rq_for_each_bvec(tmp, rq, rq_iter) { |
40326d8a SL |
550 | *bvec = tmp; |
551 | bvec++; | |
552 | } | |
553 | bvec = cmd->bvec; | |
554 | offset = 0; | |
555 | } else { | |
556 | /* | |
557 | * Same here, this bio may be started from the middle of the | |
558 | * 'bvec' because of bio splitting, so offset from the bvec | |
559 | * must be passed to iov iterator | |
560 | */ | |
561 | offset = bio->bi_iter.bi_bvec_done; | |
562 | bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); | |
40326d8a | 563 | } |
92d77332 | 564 | atomic_set(&cmd->ref, 2); |
bc07c10a | 565 | |
81ba6abd | 566 | loop_iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); |
40326d8a | 567 | iter.iov_offset = offset; |
bc07c10a ML |
568 | |
569 | cmd->iocb.ki_pos = pos; | |
570 | cmd->iocb.ki_filp = file; | |
571 | cmd->iocb.ki_complete = lo_rw_aio_complete; | |
572 | cmd->iocb.ki_flags = IOCB_DIRECT; | |
d9a08a9e | 573 | cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); |
d4478e92 SL |
574 | if (cmd->css) |
575 | kthread_associate_blkcg(cmd->css); | |
bc07c10a ML |
576 | |
577 | if (rw == WRITE) | |
bb7462b6 | 578 | ret = call_write_iter(file, &cmd->iocb, &iter); |
bc07c10a | 579 | else |
bb7462b6 | 580 | ret = call_read_iter(file, &cmd->iocb, &iter); |
bc07c10a | 581 | |
92d77332 | 582 | lo_rw_aio_do_completion(cmd); |
d4478e92 | 583 | kthread_associate_blkcg(NULL); |
92d77332 | 584 | |
bc07c10a ML |
585 | if (ret != -EIOCBQUEUED) |
586 | cmd->iocb.ki_complete(&cmd->iocb, ret, 0); | |
587 | return 0; | |
588 | } | |
589 | ||
c1c87c2b | 590 | static int do_req_filebacked(struct loop_device *lo, struct request *rq) |
bc07c10a ML |
591 | { |
592 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
c1c87c2b | 593 | loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; |
bc07c10a ML |
594 | |
595 | /* | |
596 | * lo_write_simple and lo_read_simple should have been covered | |
597 | * by io submit style function like lo_rw_aio(), one blocker | |
598 | * is that lo_read_simple() need to call flush_dcache_page after | |
599 | * the page is written from kernel, and it isn't easy to handle | |
600 | * this in io submit style function which submits all segments | |
601 | * of the req at one time. And direct read IO doesn't need to | |
602 | * run flush_dcache_page(). | |
603 | */ | |
c1c87c2b CH |
604 | switch (req_op(rq)) { |
605 | case REQ_OP_FLUSH: | |
606 | return lo_req_flush(lo, rq); | |
607 | case REQ_OP_DISCARD: | |
19372e27 | 608 | case REQ_OP_WRITE_ZEROES: |
c1c87c2b CH |
609 | return lo_discard(lo, rq, pos); |
610 | case REQ_OP_WRITE: | |
611 | if (lo->transfer) | |
612 | return lo_write_transfer(lo, rq, pos); | |
613 | else if (cmd->use_aio) | |
614 | return lo_rw_aio(lo, cmd, pos, WRITE); | |
af65aa8e | 615 | else |
c1c87c2b CH |
616 | return lo_write_simple(lo, rq, pos); |
617 | case REQ_OP_READ: | |
aa4d8616 | 618 | if (lo->transfer) |
c1c87c2b CH |
619 | return lo_read_transfer(lo, rq, pos); |
620 | else if (cmd->use_aio) | |
621 | return lo_rw_aio(lo, cmd, pos, READ); | |
aa4d8616 | 622 | else |
c1c87c2b CH |
623 | return lo_read_simple(lo, rq, pos); |
624 | default: | |
625 | WARN_ON_ONCE(1); | |
626 | return -EIO; | |
aa4d8616 | 627 | } |
1da177e4 LT |
628 | } |
629 | ||
2e5ab5f3 ML |
630 | static inline void loop_update_dio(struct loop_device *lo) |
631 | { | |
632 | __loop_update_dio(lo, io_is_direct(lo->lo_backing_file) | | |
633 | lo->use_dio); | |
634 | } | |
635 | ||
06f0e9e6 ML |
636 | static void loop_reread_partitions(struct loop_device *lo, |
637 | struct block_device *bdev) | |
638 | { | |
639 | int rc; | |
640 | ||
d57f3374 | 641 | rc = blkdev_reread_part(bdev); |
06f0e9e6 ML |
642 | if (rc) |
643 | pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", | |
644 | __func__, lo->lo_number, lo->lo_file_name, rc); | |
645 | } | |
646 | ||
d2ac838e TT |
647 | static inline int is_loop_device(struct file *file) |
648 | { | |
649 | struct inode *i = file->f_mapping->host; | |
650 | ||
651 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; | |
652 | } | |
653 | ||
654 | static int loop_validate_file(struct file *file, struct block_device *bdev) | |
655 | { | |
656 | struct inode *inode = file->f_mapping->host; | |
657 | struct file *f = file; | |
658 | ||
659 | /* Avoid recursion */ | |
660 | while (is_loop_device(f)) { | |
661 | struct loop_device *l; | |
662 | ||
663 | if (f->f_mapping->host->i_bdev == bdev) | |
664 | return -EBADF; | |
665 | ||
666 | l = f->f_mapping->host->i_bdev->bd_disk->private_data; | |
f7c8a412 | 667 | if (l->lo_state != Lo_bound) { |
d2ac838e TT |
668 | return -EINVAL; |
669 | } | |
670 | f = l->lo_backing_file; | |
671 | } | |
672 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
673 | return -EINVAL; | |
674 | return 0; | |
675 | } | |
676 | ||
1da177e4 LT |
677 | /* |
678 | * loop_change_fd switched the backing store of a loopback device to | |
679 | * a new file. This is useful for operating system installers to free up | |
680 | * the original file and in High Availability environments to switch to | |
681 | * an alternative location for the content in case of server meltdown. | |
682 | * This can only work if the loop device is used read-only, and if the | |
683 | * new backing store is the same size and type as the old backing store. | |
684 | */ | |
bb214884 AV |
685 | static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
686 | unsigned int arg) | |
1da177e4 | 687 | { |
1dded9ac | 688 | struct file *file = NULL, *old_file; |
1da177e4 | 689 | int error; |
85b0a54a | 690 | bool partscan; |
1da177e4 | 691 | |
c28445fa | 692 | error = mutex_lock_killable(&loop_ctl_mutex); |
c3710770 JK |
693 | if (error) |
694 | return error; | |
1da177e4 LT |
695 | error = -ENXIO; |
696 | if (lo->lo_state != Lo_bound) | |
1dded9ac | 697 | goto out_err; |
1da177e4 LT |
698 | |
699 | /* the loop device has to be read-only */ | |
700 | error = -EINVAL; | |
701 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) | |
1dded9ac | 702 | goto out_err; |
1da177e4 LT |
703 | |
704 | error = -EBADF; | |
705 | file = fget(arg); | |
706 | if (!file) | |
1dded9ac | 707 | goto out_err; |
1da177e4 | 708 | |
d2ac838e TT |
709 | error = loop_validate_file(file, bdev); |
710 | if (error) | |
1dded9ac | 711 | goto out_err; |
d2ac838e | 712 | |
1da177e4 LT |
713 | old_file = lo->lo_backing_file; |
714 | ||
715 | error = -EINVAL; | |
716 | ||
1da177e4 LT |
717 | /* size of the new backing store needs to be the same */ |
718 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) | |
1dded9ac | 719 | goto out_err; |
1da177e4 LT |
720 | |
721 | /* and ... switch */ | |
43cade80 OS |
722 | blk_mq_freeze_queue(lo->lo_queue); |
723 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); | |
724 | lo->lo_backing_file = file; | |
725 | lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping); | |
726 | mapping_set_gfp_mask(file->f_mapping, | |
727 | lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
728 | loop_update_dio(lo); | |
729 | blk_mq_unfreeze_queue(lo->lo_queue); | |
85b0a54a | 730 | partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; |
c3710770 | 731 | mutex_unlock(&loop_ctl_mutex); |
1dded9ac JK |
732 | /* |
733 | * We must drop file reference outside of loop_ctl_mutex as dropping | |
734 | * the file ref can take bd_mutex which creates circular locking | |
735 | * dependency. | |
736 | */ | |
737 | fput(old_file); | |
85b0a54a JK |
738 | if (partscan) |
739 | loop_reread_partitions(lo, bdev); | |
1da177e4 LT |
740 | return 0; |
741 | ||
1dded9ac | 742 | out_err: |
c3710770 | 743 | mutex_unlock(&loop_ctl_mutex); |
1dded9ac JK |
744 | if (file) |
745 | fput(file); | |
1da177e4 LT |
746 | return error; |
747 | } | |
748 | ||
ee862730 MB |
749 | /* loop sysfs attributes */ |
750 | ||
751 | static ssize_t loop_attr_show(struct device *dev, char *page, | |
752 | ssize_t (*callback)(struct loop_device *, char *)) | |
753 | { | |
34dd82af KS |
754 | struct gendisk *disk = dev_to_disk(dev); |
755 | struct loop_device *lo = disk->private_data; | |
ee862730 | 756 | |
34dd82af | 757 | return callback(lo, page); |
ee862730 MB |
758 | } |
759 | ||
760 | #define LOOP_ATTR_RO(_name) \ | |
761 | static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ | |
762 | static ssize_t loop_attr_do_show_##_name(struct device *d, \ | |
763 | struct device_attribute *attr, char *b) \ | |
764 | { \ | |
765 | return loop_attr_show(d, b, loop_attr_##_name##_show); \ | |
766 | } \ | |
767 | static struct device_attribute loop_attr_##_name = \ | |
5657a819 | 768 | __ATTR(_name, 0444, loop_attr_do_show_##_name, NULL); |
ee862730 MB |
769 | |
770 | static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) | |
771 | { | |
772 | ssize_t ret; | |
773 | char *p = NULL; | |
774 | ||
05eb0f25 | 775 | spin_lock_irq(&lo->lo_lock); |
ee862730 | 776 | if (lo->lo_backing_file) |
9bf39ab2 | 777 | p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1); |
05eb0f25 | 778 | spin_unlock_irq(&lo->lo_lock); |
ee862730 MB |
779 | |
780 | if (IS_ERR_OR_NULL(p)) | |
781 | ret = PTR_ERR(p); | |
782 | else { | |
783 | ret = strlen(p); | |
784 | memmove(buf, p, ret); | |
785 | buf[ret++] = '\n'; | |
786 | buf[ret] = 0; | |
787 | } | |
788 | ||
789 | return ret; | |
790 | } | |
791 | ||
792 | static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) | |
793 | { | |
794 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); | |
795 | } | |
796 | ||
797 | static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) | |
798 | { | |
799 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); | |
800 | } | |
801 | ||
802 | static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) | |
803 | { | |
804 | int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); | |
805 | ||
806 | return sprintf(buf, "%s\n", autoclear ? "1" : "0"); | |
807 | } | |
808 | ||
e03c8dd1 KS |
809 | static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf) |
810 | { | |
811 | int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN); | |
812 | ||
813 | return sprintf(buf, "%s\n", partscan ? "1" : "0"); | |
814 | } | |
815 | ||
2e5ab5f3 ML |
816 | static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf) |
817 | { | |
818 | int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO); | |
819 | ||
820 | return sprintf(buf, "%s\n", dio ? "1" : "0"); | |
821 | } | |
822 | ||
ee862730 MB |
823 | LOOP_ATTR_RO(backing_file); |
824 | LOOP_ATTR_RO(offset); | |
825 | LOOP_ATTR_RO(sizelimit); | |
826 | LOOP_ATTR_RO(autoclear); | |
e03c8dd1 | 827 | LOOP_ATTR_RO(partscan); |
2e5ab5f3 | 828 | LOOP_ATTR_RO(dio); |
ee862730 MB |
829 | |
830 | static struct attribute *loop_attrs[] = { | |
831 | &loop_attr_backing_file.attr, | |
832 | &loop_attr_offset.attr, | |
833 | &loop_attr_sizelimit.attr, | |
834 | &loop_attr_autoclear.attr, | |
e03c8dd1 | 835 | &loop_attr_partscan.attr, |
2e5ab5f3 | 836 | &loop_attr_dio.attr, |
ee862730 MB |
837 | NULL, |
838 | }; | |
839 | ||
840 | static struct attribute_group loop_attribute_group = { | |
841 | .name = "loop", | |
842 | .attrs= loop_attrs, | |
843 | }; | |
844 | ||
d3349b6b | 845 | static void loop_sysfs_init(struct loop_device *lo) |
ee862730 | 846 | { |
d3349b6b TH |
847 | lo->sysfs_inited = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, |
848 | &loop_attribute_group); | |
ee862730 MB |
849 | } |
850 | ||
851 | static void loop_sysfs_exit(struct loop_device *lo) | |
852 | { | |
d3349b6b TH |
853 | if (lo->sysfs_inited) |
854 | sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, | |
855 | &loop_attribute_group); | |
ee862730 MB |
856 | } |
857 | ||
dfaa2ef6 LC |
858 | static void loop_config_discard(struct loop_device *lo) |
859 | { | |
860 | struct file *file = lo->lo_backing_file; | |
861 | struct inode *inode = file->f_mapping->host; | |
862 | struct request_queue *q = lo->lo_queue; | |
863 | ||
864 | /* | |
865 | * We use punch hole to reclaim the free space used by the | |
12a64d2f | 866 | * image a.k.a. discard. However we do not support discard if |
dfaa2ef6 LC |
867 | * encryption is enabled, because it may give an attacker |
868 | * useful information. | |
869 | */ | |
870 | if ((!file->f_op->fallocate) || | |
871 | lo->lo_encrypt_key_size) { | |
872 | q->limits.discard_granularity = 0; | |
873 | q->limits.discard_alignment = 0; | |
2bb4cd5c | 874 | blk_queue_max_discard_sectors(q, 0); |
19372e27 | 875 | blk_queue_max_write_zeroes_sectors(q, 0); |
8b904b5b | 876 | blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); |
dfaa2ef6 LC |
877 | return; |
878 | } | |
879 | ||
880 | q->limits.discard_granularity = inode->i_sb->s_blocksize; | |
dfaf3c03 | 881 | q->limits.discard_alignment = 0; |
f2c6df7d | 882 | |
1e6ec9ea OS |
883 | blk_queue_max_discard_sectors(q, UINT_MAX >> 9); |
884 | blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); | |
8b904b5b | 885 | blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); |
dfaa2ef6 LC |
886 | } |
887 | ||
e03a3d7a ML |
888 | static void loop_unprepare_queue(struct loop_device *lo) |
889 | { | |
3989144f | 890 | kthread_flush_worker(&lo->worker); |
e03a3d7a ML |
891 | kthread_stop(lo->worker_task); |
892 | } | |
893 | ||
b2ee7d46 N |
894 | static int loop_kthread_worker_fn(void *worker_ptr) |
895 | { | |
896 | current->flags |= PF_LESS_THROTTLE; | |
897 | return kthread_worker_fn(worker_ptr); | |
898 | } | |
899 | ||
e03a3d7a ML |
900 | static int loop_prepare_queue(struct loop_device *lo) |
901 | { | |
3989144f | 902 | kthread_init_worker(&lo->worker); |
b2ee7d46 | 903 | lo->worker_task = kthread_run(loop_kthread_worker_fn, |
e03a3d7a ML |
904 | &lo->worker, "loop%d", lo->lo_number); |
905 | if (IS_ERR(lo->worker_task)) | |
906 | return -ENOMEM; | |
907 | set_user_nice(lo->worker_task, MIN_NICE); | |
908 | return 0; | |
909 | } | |
910 | ||
56a85fd8 HH |
911 | static void loop_update_rotational(struct loop_device *lo) |
912 | { | |
913 | struct file *file = lo->lo_backing_file; | |
914 | struct inode *file_inode = file->f_mapping->host; | |
915 | struct block_device *file_bdev = file_inode->i_sb->s_bdev; | |
916 | struct request_queue *q = lo->lo_queue; | |
917 | bool nonrot = true; | |
918 | ||
919 | /* not all filesystems (e.g. tmpfs) have a sb->s_bdev */ | |
920 | if (file_bdev) | |
921 | nonrot = blk_queue_nonrot(bdev_get_queue(file_bdev)); | |
922 | ||
923 | if (nonrot) | |
924 | blk_queue_flag_set(QUEUE_FLAG_NONROT, q); | |
925 | else | |
926 | blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); | |
927 | } | |
928 | ||
bb214884 | 929 | static int loop_set_fd(struct loop_device *lo, fmode_t mode, |
1da177e4 LT |
930 | struct block_device *bdev, unsigned int arg) |
931 | { | |
d2ac838e | 932 | struct file *file; |
1da177e4 LT |
933 | struct inode *inode; |
934 | struct address_space *mapping; | |
1da177e4 LT |
935 | int lo_flags = 0; |
936 | int error; | |
937 | loff_t size; | |
85b0a54a | 938 | bool partscan; |
1da177e4 LT |
939 | |
940 | /* This is safe, since we have a reference from open(). */ | |
941 | __module_get(THIS_MODULE); | |
942 | ||
943 | error = -EBADF; | |
944 | file = fget(arg); | |
945 | if (!file) | |
946 | goto out; | |
947 | ||
c28445fa | 948 | error = mutex_lock_killable(&loop_ctl_mutex); |
757ecf40 JK |
949 | if (error) |
950 | goto out_putf; | |
951 | ||
1da177e4 LT |
952 | error = -EBUSY; |
953 | if (lo->lo_state != Lo_unbound) | |
757ecf40 | 954 | goto out_unlock; |
1da177e4 | 955 | |
d2ac838e TT |
956 | error = loop_validate_file(file, bdev); |
957 | if (error) | |
757ecf40 | 958 | goto out_unlock; |
1da177e4 LT |
959 | |
960 | mapping = file->f_mapping; | |
961 | inode = mapping->host; | |
962 | ||
456be148 | 963 | if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || |
283e7e5d | 964 | !file->f_op->write_iter) |
456be148 | 965 | lo_flags |= LO_FLAGS_READ_ONLY; |
ba52de12 | 966 | |
456be148 | 967 | error = -EFBIG; |
1da177e4 | 968 | size = get_loop_size(lo, file); |
456be148 | 969 | if ((loff_t)(sector_t)size != size) |
757ecf40 | 970 | goto out_unlock; |
e03a3d7a ML |
971 | error = loop_prepare_queue(lo); |
972 | if (error) | |
757ecf40 | 973 | goto out_unlock; |
1da177e4 | 974 | |
456be148 | 975 | error = 0; |
1da177e4 LT |
976 | |
977 | set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); | |
978 | ||
2e5ab5f3 | 979 | lo->use_dio = false; |
1da177e4 LT |
980 | lo->lo_device = bdev; |
981 | lo->lo_flags = lo_flags; | |
982 | lo->lo_backing_file = file; | |
aa4d8616 | 983 | lo->transfer = NULL; |
1da177e4 LT |
984 | lo->ioctl = NULL; |
985 | lo->lo_sizelimit = 0; | |
986 | lo->old_gfp_mask = mapping_gfp_mask(mapping); | |
987 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
988 | ||
68db1961 | 989 | if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
21d0727f | 990 | blk_queue_write_cache(lo->lo_queue, true, false); |
68db1961 | 991 | |
56a85fd8 | 992 | loop_update_rotational(lo); |
2e5ab5f3 | 993 | loop_update_dio(lo); |
73285082 | 994 | set_capacity(lo->lo_disk, size); |
1da177e4 | 995 | bd_set_size(bdev, size << 9); |
ee862730 | 996 | loop_sysfs_init(lo); |
c3473c63 DZ |
997 | /* let user-space know about the new size */ |
998 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1da177e4 | 999 | |
8a0740c4 OS |
1000 | set_blocksize(bdev, S_ISBLK(inode->i_mode) ? |
1001 | block_size(inode->i_bdev) : PAGE_SIZE); | |
1da177e4 | 1002 | |
6c997918 | 1003 | lo->lo_state = Lo_bound; |
e03c8dd1 KS |
1004 | if (part_shift) |
1005 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
85b0a54a | 1006 | partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; |
c1681bf8 AP |
1007 | |
1008 | /* Grab the block_device to prevent its destruction after we | |
a2505b79 | 1009 | * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev). |
c1681bf8 AP |
1010 | */ |
1011 | bdgrab(bdev); | |
757ecf40 | 1012 | mutex_unlock(&loop_ctl_mutex); |
85b0a54a JK |
1013 | if (partscan) |
1014 | loop_reread_partitions(lo, bdev); | |
1da177e4 LT |
1015 | return 0; |
1016 | ||
757ecf40 JK |
1017 | out_unlock: |
1018 | mutex_unlock(&loop_ctl_mutex); | |
1019 | out_putf: | |
1da177e4 | 1020 | fput(file); |
757ecf40 | 1021 | out: |
1da177e4 LT |
1022 | /* This is safe: open() is still holding a reference. */ |
1023 | module_put(THIS_MODULE); | |
1024 | return error; | |
1025 | } | |
1026 | ||
1027 | static int | |
1028 | loop_release_xfer(struct loop_device *lo) | |
1029 | { | |
1030 | int err = 0; | |
1031 | struct loop_func_table *xfer = lo->lo_encryption; | |
1032 | ||
1033 | if (xfer) { | |
1034 | if (xfer->release) | |
1035 | err = xfer->release(lo); | |
1036 | lo->transfer = NULL; | |
1037 | lo->lo_encryption = NULL; | |
1038 | module_put(xfer->owner); | |
1039 | } | |
1040 | return err; | |
1041 | } | |
1042 | ||
1043 | static int | |
1044 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, | |
1045 | const struct loop_info64 *i) | |
1046 | { | |
1047 | int err = 0; | |
1048 | ||
1049 | if (xfer) { | |
1050 | struct module *owner = xfer->owner; | |
1051 | ||
1052 | if (!try_module_get(owner)) | |
1053 | return -EINVAL; | |
1054 | if (xfer->init) | |
1055 | err = xfer->init(lo, i); | |
1056 | if (err) | |
1057 | module_put(owner); | |
1058 | else | |
1059 | lo->lo_encryption = xfer; | |
1060 | } | |
1061 | return err; | |
1062 | } | |
1063 | ||
0da03cab | 1064 | static int __loop_clr_fd(struct loop_device *lo, bool release) |
1da177e4 | 1065 | { |
7ccd0791 | 1066 | struct file *filp = NULL; |
b4e3ca1a | 1067 | gfp_t gfp = lo->old_gfp_mask; |
4c823cc3 | 1068 | struct block_device *bdev = lo->lo_device; |
7ccd0791 | 1069 | int err = 0; |
0da03cab JK |
1070 | bool partscan = false; |
1071 | int lo_number; | |
1da177e4 | 1072 | |
7ccd0791 JK |
1073 | mutex_lock(&loop_ctl_mutex); |
1074 | if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) { | |
1075 | err = -ENXIO; | |
1076 | goto out_unlock; | |
1077 | } | |
1da177e4 | 1078 | |
7ccd0791 JK |
1079 | filp = lo->lo_backing_file; |
1080 | if (filp == NULL) { | |
1081 | err = -EINVAL; | |
1082 | goto out_unlock; | |
1083 | } | |
1da177e4 | 1084 | |
f8933667 ML |
1085 | /* freeze request queue during the transition */ |
1086 | blk_mq_freeze_queue(lo->lo_queue); | |
1087 | ||
1da177e4 | 1088 | spin_lock_irq(&lo->lo_lock); |
1da177e4 | 1089 | lo->lo_backing_file = NULL; |
05eb0f25 | 1090 | spin_unlock_irq(&lo->lo_lock); |
1da177e4 LT |
1091 | |
1092 | loop_release_xfer(lo); | |
1093 | lo->transfer = NULL; | |
1094 | lo->ioctl = NULL; | |
1095 | lo->lo_device = NULL; | |
1096 | lo->lo_encryption = NULL; | |
1097 | lo->lo_offset = 0; | |
1098 | lo->lo_sizelimit = 0; | |
1099 | lo->lo_encrypt_key_size = 0; | |
1da177e4 LT |
1100 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
1101 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); | |
1102 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); | |
89e4fdec | 1103 | blk_queue_logical_block_size(lo->lo_queue, 512); |
bf093753 OS |
1104 | blk_queue_physical_block_size(lo->lo_queue, 512); |
1105 | blk_queue_io_min(lo->lo_queue, 512); | |
c1681bf8 AP |
1106 | if (bdev) { |
1107 | bdput(bdev); | |
bb214884 | 1108 | invalidate_bdev(bdev); |
eedffa28 | 1109 | bdev->bd_inode->i_mapping->wb_err = 0; |
c1681bf8 | 1110 | } |
73285082 | 1111 | set_capacity(lo->lo_disk, 0); |
51a0bb0c | 1112 | loop_sysfs_exit(lo); |
c3473c63 | 1113 | if (bdev) { |
bb214884 | 1114 | bd_set_size(bdev, 0); |
c3473c63 DZ |
1115 | /* let user-space know about this change */ |
1116 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1117 | } | |
1da177e4 | 1118 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
1da177e4 LT |
1119 | /* This is safe: open() is still holding a reference. */ |
1120 | module_put(THIS_MODULE); | |
f8933667 ML |
1121 | blk_mq_unfreeze_queue(lo->lo_queue); |
1122 | ||
0da03cab JK |
1123 | partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev; |
1124 | lo_number = lo->lo_number; | |
0da03cab JK |
1125 | loop_unprepare_queue(lo); |
1126 | out_unlock: | |
1127 | mutex_unlock(&loop_ctl_mutex); | |
1128 | if (partscan) { | |
d57f3374 JK |
1129 | /* |
1130 | * bd_mutex has been held already in release path, so don't | |
1131 | * acquire it if this function is called in such case. | |
1132 | * | |
1133 | * If the reread partition isn't from release path, lo_refcnt | |
1134 | * must be at least one and it can only become zero when the | |
1135 | * current holder is released. | |
1136 | */ | |
0da03cab | 1137 | if (release) |
d57f3374 JK |
1138 | err = __blkdev_reread_part(bdev); |
1139 | else | |
1140 | err = blkdev_reread_part(bdev); | |
40853d6f DZ |
1141 | if (err) |
1142 | pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", | |
1143 | __func__, lo_number, err); | |
d57f3374 JK |
1144 | /* Device is gone, no point in returning error */ |
1145 | err = 0; | |
1146 | } | |
758a58d0 DZ |
1147 | |
1148 | /* | |
1149 | * lo->lo_state is set to Lo_unbound here after above partscan has | |
1150 | * finished. | |
1151 | * | |
1152 | * There cannot be anybody else entering __loop_clr_fd() as | |
1153 | * lo->lo_backing_file is already cleared and Lo_rundown state | |
1154 | * protects us from all the other places trying to change the 'lo' | |
1155 | * device. | |
1156 | */ | |
1157 | mutex_lock(&loop_ctl_mutex); | |
1158 | lo->lo_flags = 0; | |
1159 | if (!part_shift) | |
1160 | lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; | |
1161 | lo->lo_state = Lo_unbound; | |
1162 | mutex_unlock(&loop_ctl_mutex); | |
1163 | ||
f028f3b2 | 1164 | /* |
310ca162 TH |
1165 | * Need not hold loop_ctl_mutex to fput backing file. |
1166 | * Calling fput holding loop_ctl_mutex triggers a circular | |
f028f3b2 | 1167 | * lock dependency possibility warning as fput can take |
310ca162 | 1168 | * bd_mutex which is usually taken before loop_ctl_mutex. |
f028f3b2 | 1169 | */ |
7ccd0791 JK |
1170 | if (filp) |
1171 | fput(filp); | |
1172 | return err; | |
1da177e4 LT |
1173 | } |
1174 | ||
a2505b79 JK |
1175 | static int loop_clr_fd(struct loop_device *lo) |
1176 | { | |
7ccd0791 JK |
1177 | int err; |
1178 | ||
c28445fa | 1179 | err = mutex_lock_killable(&loop_ctl_mutex); |
7ccd0791 JK |
1180 | if (err) |
1181 | return err; | |
1182 | if (lo->lo_state != Lo_bound) { | |
1183 | mutex_unlock(&loop_ctl_mutex); | |
a2505b79 | 1184 | return -ENXIO; |
7ccd0791 | 1185 | } |
a2505b79 JK |
1186 | /* |
1187 | * If we've explicitly asked to tear down the loop device, | |
1188 | * and it has an elevated reference count, set it for auto-teardown when | |
1189 | * the last reference goes away. This stops $!~#$@ udev from | |
1190 | * preventing teardown because it decided that it needs to run blkid on | |
1191 | * the loopback device whenever they appear. xfstests is notorious for | |
1192 | * failing tests because blkid via udev races with a losetup | |
1193 | * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d | |
1194 | * command to fail with EBUSY. | |
1195 | */ | |
1196 | if (atomic_read(&lo->lo_refcnt) > 1) { | |
1197 | lo->lo_flags |= LO_FLAGS_AUTOCLEAR; | |
1198 | mutex_unlock(&loop_ctl_mutex); | |
1199 | return 0; | |
1200 | } | |
1201 | lo->lo_state = Lo_rundown; | |
7ccd0791 | 1202 | mutex_unlock(&loop_ctl_mutex); |
a2505b79 | 1203 | |
0da03cab | 1204 | return __loop_clr_fd(lo, false); |
a2505b79 JK |
1205 | } |
1206 | ||
1da177e4 LT |
1207 | static int |
1208 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) | |
1209 | { | |
1210 | int err; | |
1211 | struct loop_func_table *xfer; | |
e4849737 | 1212 | kuid_t uid = current_uid(); |
85b0a54a JK |
1213 | struct block_device *bdev; |
1214 | bool partscan = false; | |
1da177e4 | 1215 | |
c28445fa | 1216 | err = mutex_lock_killable(&loop_ctl_mutex); |
550df5fd JK |
1217 | if (err) |
1218 | return err; | |
b0fafa81 | 1219 | if (lo->lo_encrypt_key_size && |
e4849737 | 1220 | !uid_eq(lo->lo_key_owner, uid) && |
550df5fd JK |
1221 | !capable(CAP_SYS_ADMIN)) { |
1222 | err = -EPERM; | |
1223 | goto out_unlock; | |
1224 | } | |
1225 | if (lo->lo_state != Lo_bound) { | |
1226 | err = -ENXIO; | |
1227 | goto out_unlock; | |
1228 | } | |
1229 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) { | |
1230 | err = -EINVAL; | |
1231 | goto out_unlock; | |
1232 | } | |
1da177e4 | 1233 | |
5db470e2 JK |
1234 | if (lo->lo_offset != info->lo_offset || |
1235 | lo->lo_sizelimit != info->lo_sizelimit) { | |
1236 | sync_blockdev(lo->lo_device); | |
1237 | kill_bdev(lo->lo_device); | |
1238 | } | |
1239 | ||
ecdd0959 ML |
1240 | /* I/O need to be drained during transfer transition */ |
1241 | blk_mq_freeze_queue(lo->lo_queue); | |
1242 | ||
1da177e4 LT |
1243 | err = loop_release_xfer(lo); |
1244 | if (err) | |
550df5fd | 1245 | goto out_unfreeze; |
1da177e4 LT |
1246 | |
1247 | if (info->lo_encrypt_type) { | |
1248 | unsigned int type = info->lo_encrypt_type; | |
1249 | ||
1e047eaa TH |
1250 | if (type >= MAX_LO_CRYPT) { |
1251 | err = -EINVAL; | |
550df5fd | 1252 | goto out_unfreeze; |
1e047eaa | 1253 | } |
1da177e4 | 1254 | xfer = xfer_funcs[type]; |
1e047eaa TH |
1255 | if (xfer == NULL) { |
1256 | err = -EINVAL; | |
550df5fd | 1257 | goto out_unfreeze; |
1e047eaa | 1258 | } |
1da177e4 LT |
1259 | } else |
1260 | xfer = NULL; | |
1261 | ||
1262 | err = loop_init_xfer(lo, xfer, info); | |
1263 | if (err) | |
550df5fd | 1264 | goto out_unfreeze; |
1da177e4 LT |
1265 | |
1266 | if (lo->lo_offset != info->lo_offset || | |
1e6ec9ea | 1267 | lo->lo_sizelimit != info->lo_sizelimit) { |
5db470e2 JK |
1268 | /* kill_bdev should have truncated all the pages */ |
1269 | if (lo->lo_device->bd_inode->i_mapping->nrpages) { | |
1270 | err = -EAGAIN; | |
1271 | pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", | |
1272 | __func__, lo->lo_number, lo->lo_file_name, | |
1273 | lo->lo_device->bd_inode->i_mapping->nrpages); | |
1274 | goto out_unfreeze; | |
1275 | } | |
1e6ec9ea | 1276 | if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) { |
ecdd0959 | 1277 | err = -EFBIG; |
550df5fd | 1278 | goto out_unfreeze; |
ecdd0959 | 1279 | } |
b040ad9c | 1280 | } |
541c742a | 1281 | |
dfaa2ef6 | 1282 | loop_config_discard(lo); |
1da177e4 LT |
1283 | |
1284 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); | |
1285 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); | |
1286 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; | |
1287 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; | |
1288 | ||
1289 | if (!xfer) | |
1290 | xfer = &none_funcs; | |
1291 | lo->transfer = xfer->transfer; | |
1292 | lo->ioctl = xfer->ioctl; | |
1293 | ||
96c58655 DW |
1294 | if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != |
1295 | (info->lo_flags & LO_FLAGS_AUTOCLEAR)) | |
1296 | lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; | |
1297 | ||
1da177e4 LT |
1298 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; |
1299 | lo->lo_init[0] = info->lo_init[0]; | |
1300 | lo->lo_init[1] = info->lo_init[1]; | |
1301 | if (info->lo_encrypt_key_size) { | |
1302 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, | |
1303 | info->lo_encrypt_key_size); | |
b0fafa81 | 1304 | lo->lo_key_owner = uid; |
aa4d8616 | 1305 | } |
1da177e4 | 1306 | |
2e5ab5f3 ML |
1307 | /* update dio if lo_offset or transfer is changed */ |
1308 | __loop_update_dio(lo, lo->use_dio); | |
1309 | ||
550df5fd | 1310 | out_unfreeze: |
ecdd0959 | 1311 | blk_mq_unfreeze_queue(lo->lo_queue); |
e02898b4 OS |
1312 | |
1313 | if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) && | |
1314 | !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { | |
1315 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
1316 | lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; | |
85b0a54a JK |
1317 | bdev = lo->lo_device; |
1318 | partscan = true; | |
e02898b4 | 1319 | } |
550df5fd JK |
1320 | out_unlock: |
1321 | mutex_unlock(&loop_ctl_mutex); | |
85b0a54a JK |
1322 | if (partscan) |
1323 | loop_reread_partitions(lo, bdev); | |
e02898b4 | 1324 | |
ecdd0959 | 1325 | return err; |
1da177e4 LT |
1326 | } |
1327 | ||
1328 | static int | |
1329 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) | |
1330 | { | |
b1ab5fa3 | 1331 | struct path path; |
1da177e4 | 1332 | struct kstat stat; |
2d1d4c1e | 1333 | int ret; |
1da177e4 | 1334 | |
c28445fa | 1335 | ret = mutex_lock_killable(&loop_ctl_mutex); |
4a5ce9ba JK |
1336 | if (ret) |
1337 | return ret; | |
2d1d4c1e | 1338 | if (lo->lo_state != Lo_bound) { |
310ca162 | 1339 | mutex_unlock(&loop_ctl_mutex); |
1da177e4 | 1340 | return -ENXIO; |
2d1d4c1e OS |
1341 | } |
1342 | ||
1da177e4 LT |
1343 | memset(info, 0, sizeof(*info)); |
1344 | info->lo_number = lo->lo_number; | |
1da177e4 LT |
1345 | info->lo_offset = lo->lo_offset; |
1346 | info->lo_sizelimit = lo->lo_sizelimit; | |
1347 | info->lo_flags = lo->lo_flags; | |
1348 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); | |
1349 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); | |
1350 | info->lo_encrypt_type = | |
1351 | lo->lo_encryption ? lo->lo_encryption->number : 0; | |
1352 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { | |
1353 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; | |
1354 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, | |
1355 | lo->lo_encrypt_key_size); | |
1356 | } | |
2d1d4c1e | 1357 | |
310ca162 | 1358 | /* Drop loop_ctl_mutex while we call into the filesystem. */ |
b1ab5fa3 TH |
1359 | path = lo->lo_backing_file->f_path; |
1360 | path_get(&path); | |
310ca162 | 1361 | mutex_unlock(&loop_ctl_mutex); |
b1ab5fa3 | 1362 | ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT); |
2d1d4c1e OS |
1363 | if (!ret) { |
1364 | info->lo_device = huge_encode_dev(stat.dev); | |
1365 | info->lo_inode = stat.ino; | |
1366 | info->lo_rdevice = huge_encode_dev(stat.rdev); | |
1367 | } | |
b1ab5fa3 | 1368 | path_put(&path); |
2d1d4c1e | 1369 | return ret; |
1da177e4 LT |
1370 | } |
1371 | ||
1372 | static void | |
1373 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) | |
1374 | { | |
1375 | memset(info64, 0, sizeof(*info64)); | |
1376 | info64->lo_number = info->lo_number; | |
1377 | info64->lo_device = info->lo_device; | |
1378 | info64->lo_inode = info->lo_inode; | |
1379 | info64->lo_rdevice = info->lo_rdevice; | |
1380 | info64->lo_offset = info->lo_offset; | |
1381 | info64->lo_sizelimit = 0; | |
1382 | info64->lo_encrypt_type = info->lo_encrypt_type; | |
1383 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; | |
1384 | info64->lo_flags = info->lo_flags; | |
1385 | info64->lo_init[0] = info->lo_init[0]; | |
1386 | info64->lo_init[1] = info->lo_init[1]; | |
1387 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1388 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); | |
1389 | else | |
1390 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); | |
1391 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); | |
1392 | } | |
1393 | ||
1394 | static int | |
1395 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) | |
1396 | { | |
1397 | memset(info, 0, sizeof(*info)); | |
1398 | info->lo_number = info64->lo_number; | |
1399 | info->lo_device = info64->lo_device; | |
1400 | info->lo_inode = info64->lo_inode; | |
1401 | info->lo_rdevice = info64->lo_rdevice; | |
1402 | info->lo_offset = info64->lo_offset; | |
1403 | info->lo_encrypt_type = info64->lo_encrypt_type; | |
1404 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1405 | info->lo_flags = info64->lo_flags; | |
1406 | info->lo_init[0] = info64->lo_init[0]; | |
1407 | info->lo_init[1] = info64->lo_init[1]; | |
1408 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1409 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1410 | else | |
1411 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1412 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1413 | ||
1414 | /* error in case values were truncated */ | |
1415 | if (info->lo_device != info64->lo_device || | |
1416 | info->lo_rdevice != info64->lo_rdevice || | |
1417 | info->lo_inode != info64->lo_inode || | |
1418 | info->lo_offset != info64->lo_offset) | |
1419 | return -EOVERFLOW; | |
1420 | ||
1421 | return 0; | |
1422 | } | |
1423 | ||
1424 | static int | |
1425 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) | |
1426 | { | |
1427 | struct loop_info info; | |
1428 | struct loop_info64 info64; | |
1429 | ||
1430 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) | |
1431 | return -EFAULT; | |
1432 | loop_info64_from_old(&info, &info64); | |
1433 | return loop_set_status(lo, &info64); | |
1434 | } | |
1435 | ||
1436 | static int | |
1437 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) | |
1438 | { | |
1439 | struct loop_info64 info64; | |
1440 | ||
1441 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) | |
1442 | return -EFAULT; | |
1443 | return loop_set_status(lo, &info64); | |
1444 | } | |
1445 | ||
1446 | static int | |
1447 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { | |
1448 | struct loop_info info; | |
1449 | struct loop_info64 info64; | |
bdac616d | 1450 | int err; |
1da177e4 | 1451 | |
4a5ce9ba | 1452 | if (!arg) |
bdac616d | 1453 | return -EINVAL; |
bdac616d | 1454 | err = loop_get_status(lo, &info64); |
1da177e4 LT |
1455 | if (!err) |
1456 | err = loop_info64_to_old(&info64, &info); | |
1457 | if (!err && copy_to_user(arg, &info, sizeof(info))) | |
1458 | err = -EFAULT; | |
1459 | ||
1460 | return err; | |
1461 | } | |
1462 | ||
1463 | static int | |
1464 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { | |
1465 | struct loop_info64 info64; | |
bdac616d | 1466 | int err; |
1da177e4 | 1467 | |
4a5ce9ba | 1468 | if (!arg) |
bdac616d | 1469 | return -EINVAL; |
bdac616d | 1470 | err = loop_get_status(lo, &info64); |
1da177e4 LT |
1471 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) |
1472 | err = -EFAULT; | |
1473 | ||
1474 | return err; | |
1475 | } | |
1476 | ||
51001b7d | 1477 | static int loop_set_capacity(struct loop_device *lo) |
53d66608 | 1478 | { |
53d66608 | 1479 | if (unlikely(lo->lo_state != Lo_bound)) |
7b0576a3 | 1480 | return -ENXIO; |
53d66608 | 1481 | |
1e6ec9ea | 1482 | return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); |
53d66608 O |
1483 | } |
1484 | ||
ab1cb278 ML |
1485 | static int loop_set_dio(struct loop_device *lo, unsigned long arg) |
1486 | { | |
1487 | int error = -ENXIO; | |
1488 | if (lo->lo_state != Lo_bound) | |
1489 | goto out; | |
1490 | ||
1491 | __loop_update_dio(lo, !!arg); | |
1492 | if (lo->use_dio == !!arg) | |
1493 | return 0; | |
1494 | error = -EINVAL; | |
1495 | out: | |
1496 | return error; | |
1497 | } | |
1498 | ||
89e4fdec OS |
1499 | static int loop_set_block_size(struct loop_device *lo, unsigned long arg) |
1500 | { | |
5db470e2 JK |
1501 | int err = 0; |
1502 | ||
89e4fdec OS |
1503 | if (lo->lo_state != Lo_bound) |
1504 | return -ENXIO; | |
1505 | ||
1506 | if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg)) | |
1507 | return -EINVAL; | |
1508 | ||
5db470e2 JK |
1509 | if (lo->lo_queue->limits.logical_block_size != arg) { |
1510 | sync_blockdev(lo->lo_device); | |
1511 | kill_bdev(lo->lo_device); | |
1512 | } | |
1513 | ||
89e4fdec OS |
1514 | blk_mq_freeze_queue(lo->lo_queue); |
1515 | ||
5db470e2 JK |
1516 | /* kill_bdev should have truncated all the pages */ |
1517 | if (lo->lo_queue->limits.logical_block_size != arg && | |
1518 | lo->lo_device->bd_inode->i_mapping->nrpages) { | |
1519 | err = -EAGAIN; | |
1520 | pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", | |
1521 | __func__, lo->lo_number, lo->lo_file_name, | |
1522 | lo->lo_device->bd_inode->i_mapping->nrpages); | |
1523 | goto out_unfreeze; | |
1524 | } | |
1525 | ||
89e4fdec | 1526 | blk_queue_logical_block_size(lo->lo_queue, arg); |
bf093753 OS |
1527 | blk_queue_physical_block_size(lo->lo_queue, arg); |
1528 | blk_queue_io_min(lo->lo_queue, arg); | |
89e4fdec | 1529 | loop_update_dio(lo); |
5db470e2 | 1530 | out_unfreeze: |
89e4fdec OS |
1531 | blk_mq_unfreeze_queue(lo->lo_queue); |
1532 | ||
5db470e2 | 1533 | return err; |
89e4fdec OS |
1534 | } |
1535 | ||
a1316544 JK |
1536 | static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd, |
1537 | unsigned long arg) | |
1da177e4 | 1538 | { |
1da177e4 LT |
1539 | int err; |
1540 | ||
c28445fa | 1541 | err = mutex_lock_killable(&loop_ctl_mutex); |
3148ffbd | 1542 | if (err) |
a1316544 JK |
1543 | return err; |
1544 | switch (cmd) { | |
1545 | case LOOP_SET_CAPACITY: | |
1546 | err = loop_set_capacity(lo); | |
1547 | break; | |
1548 | case LOOP_SET_DIRECT_IO: | |
1549 | err = loop_set_dio(lo, arg); | |
1550 | break; | |
1551 | case LOOP_SET_BLOCK_SIZE: | |
1552 | err = loop_set_block_size(lo, arg); | |
1553 | break; | |
1554 | default: | |
1555 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; | |
1556 | } | |
1557 | mutex_unlock(&loop_ctl_mutex); | |
1558 | return err; | |
1559 | } | |
1560 | ||
1561 | static int lo_ioctl(struct block_device *bdev, fmode_t mode, | |
1562 | unsigned int cmd, unsigned long arg) | |
1563 | { | |
1564 | struct loop_device *lo = bdev->bd_disk->private_data; | |
1565 | int err; | |
3148ffbd | 1566 | |
1da177e4 LT |
1567 | switch (cmd) { |
1568 | case LOOP_SET_FD: | |
757ecf40 | 1569 | return loop_set_fd(lo, mode, bdev, arg); |
1da177e4 | 1570 | case LOOP_CHANGE_FD: |
c3710770 | 1571 | return loop_change_fd(lo, bdev, arg); |
1da177e4 | 1572 | case LOOP_CLR_FD: |
7ccd0791 | 1573 | return loop_clr_fd(lo); |
1da177e4 | 1574 | case LOOP_SET_STATUS: |
7035b5df | 1575 | err = -EPERM; |
a1316544 | 1576 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { |
7035b5df DM |
1577 | err = loop_set_status_old(lo, |
1578 | (struct loop_info __user *)arg); | |
a1316544 | 1579 | } |
1da177e4 LT |
1580 | break; |
1581 | case LOOP_GET_STATUS: | |
4a5ce9ba | 1582 | return loop_get_status_old(lo, (struct loop_info __user *) arg); |
1da177e4 | 1583 | case LOOP_SET_STATUS64: |
7035b5df | 1584 | err = -EPERM; |
a1316544 | 1585 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { |
7035b5df DM |
1586 | err = loop_set_status64(lo, |
1587 | (struct loop_info64 __user *) arg); | |
a1316544 | 1588 | } |
1da177e4 LT |
1589 | break; |
1590 | case LOOP_GET_STATUS64: | |
4a5ce9ba | 1591 | return loop_get_status64(lo, (struct loop_info64 __user *) arg); |
a1316544 | 1592 | case LOOP_SET_CAPACITY: |
ab1cb278 | 1593 | case LOOP_SET_DIRECT_IO: |
89e4fdec | 1594 | case LOOP_SET_BLOCK_SIZE: |
a1316544 JK |
1595 | if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN)) |
1596 | return -EPERM; | |
1597 | /* Fall through */ | |
1da177e4 | 1598 | default: |
a1316544 JK |
1599 | err = lo_simple_ioctl(lo, cmd, arg); |
1600 | break; | |
1da177e4 | 1601 | } |
f028f3b2 | 1602 | |
1da177e4 LT |
1603 | return err; |
1604 | } | |
1605 | ||
863d5b82 DH |
1606 | #ifdef CONFIG_COMPAT |
1607 | struct compat_loop_info { | |
1608 | compat_int_t lo_number; /* ioctl r/o */ | |
1609 | compat_dev_t lo_device; /* ioctl r/o */ | |
1610 | compat_ulong_t lo_inode; /* ioctl r/o */ | |
1611 | compat_dev_t lo_rdevice; /* ioctl r/o */ | |
1612 | compat_int_t lo_offset; | |
1613 | compat_int_t lo_encrypt_type; | |
1614 | compat_int_t lo_encrypt_key_size; /* ioctl w/o */ | |
1615 | compat_int_t lo_flags; /* ioctl r/o */ | |
1616 | char lo_name[LO_NAME_SIZE]; | |
1617 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ | |
1618 | compat_ulong_t lo_init[2]; | |
1619 | char reserved[4]; | |
1620 | }; | |
1621 | ||
1622 | /* | |
1623 | * Transfer 32-bit compatibility structure in userspace to 64-bit loop info | |
1624 | * - noinlined to reduce stack space usage in main part of driver | |
1625 | */ | |
1626 | static noinline int | |
ba674cfc | 1627 | loop_info64_from_compat(const struct compat_loop_info __user *arg, |
863d5b82 DH |
1628 | struct loop_info64 *info64) |
1629 | { | |
1630 | struct compat_loop_info info; | |
1631 | ||
1632 | if (copy_from_user(&info, arg, sizeof(info))) | |
1633 | return -EFAULT; | |
1634 | ||
1635 | memset(info64, 0, sizeof(*info64)); | |
1636 | info64->lo_number = info.lo_number; | |
1637 | info64->lo_device = info.lo_device; | |
1638 | info64->lo_inode = info.lo_inode; | |
1639 | info64->lo_rdevice = info.lo_rdevice; | |
1640 | info64->lo_offset = info.lo_offset; | |
1641 | info64->lo_sizelimit = 0; | |
1642 | info64->lo_encrypt_type = info.lo_encrypt_type; | |
1643 | info64->lo_encrypt_key_size = info.lo_encrypt_key_size; | |
1644 | info64->lo_flags = info.lo_flags; | |
1645 | info64->lo_init[0] = info.lo_init[0]; | |
1646 | info64->lo_init[1] = info.lo_init[1]; | |
1647 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1648 | memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); | |
1649 | else | |
1650 | memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); | |
1651 | memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); | |
1652 | return 0; | |
1653 | } | |
1654 | ||
1655 | /* | |
1656 | * Transfer 64-bit loop info to 32-bit compatibility structure in userspace | |
1657 | * - noinlined to reduce stack space usage in main part of driver | |
1658 | */ | |
1659 | static noinline int | |
1660 | loop_info64_to_compat(const struct loop_info64 *info64, | |
1661 | struct compat_loop_info __user *arg) | |
1662 | { | |
1663 | struct compat_loop_info info; | |
1664 | ||
1665 | memset(&info, 0, sizeof(info)); | |
1666 | info.lo_number = info64->lo_number; | |
1667 | info.lo_device = info64->lo_device; | |
1668 | info.lo_inode = info64->lo_inode; | |
1669 | info.lo_rdevice = info64->lo_rdevice; | |
1670 | info.lo_offset = info64->lo_offset; | |
1671 | info.lo_encrypt_type = info64->lo_encrypt_type; | |
1672 | info.lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1673 | info.lo_flags = info64->lo_flags; | |
1674 | info.lo_init[0] = info64->lo_init[0]; | |
1675 | info.lo_init[1] = info64->lo_init[1]; | |
1676 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1677 | memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1678 | else | |
1679 | memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1680 | memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1681 | ||
1682 | /* error in case values were truncated */ | |
1683 | if (info.lo_device != info64->lo_device || | |
1684 | info.lo_rdevice != info64->lo_rdevice || | |
1685 | info.lo_inode != info64->lo_inode || | |
1686 | info.lo_offset != info64->lo_offset || | |
1687 | info.lo_init[0] != info64->lo_init[0] || | |
1688 | info.lo_init[1] != info64->lo_init[1]) | |
1689 | return -EOVERFLOW; | |
1690 | ||
1691 | if (copy_to_user(arg, &info, sizeof(info))) | |
1692 | return -EFAULT; | |
1693 | return 0; | |
1694 | } | |
1695 | ||
1696 | static int | |
1697 | loop_set_status_compat(struct loop_device *lo, | |
1698 | const struct compat_loop_info __user *arg) | |
1699 | { | |
1700 | struct loop_info64 info64; | |
1701 | int ret; | |
1702 | ||
1703 | ret = loop_info64_from_compat(arg, &info64); | |
1704 | if (ret < 0) | |
1705 | return ret; | |
1706 | return loop_set_status(lo, &info64); | |
1707 | } | |
1708 | ||
1709 | static int | |
1710 | loop_get_status_compat(struct loop_device *lo, | |
1711 | struct compat_loop_info __user *arg) | |
1712 | { | |
1713 | struct loop_info64 info64; | |
bdac616d | 1714 | int err; |
863d5b82 | 1715 | |
4a5ce9ba | 1716 | if (!arg) |
bdac616d | 1717 | return -EINVAL; |
bdac616d | 1718 | err = loop_get_status(lo, &info64); |
863d5b82 DH |
1719 | if (!err) |
1720 | err = loop_info64_to_compat(&info64, arg); | |
1721 | return err; | |
1722 | } | |
1723 | ||
bb214884 AV |
1724 | static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
1725 | unsigned int cmd, unsigned long arg) | |
863d5b82 | 1726 | { |
bb214884 | 1727 | struct loop_device *lo = bdev->bd_disk->private_data; |
863d5b82 DH |
1728 | int err; |
1729 | ||
863d5b82 DH |
1730 | switch(cmd) { |
1731 | case LOOP_SET_STATUS: | |
550df5fd JK |
1732 | err = loop_set_status_compat(lo, |
1733 | (const struct compat_loop_info __user *)arg); | |
863d5b82 DH |
1734 | break; |
1735 | case LOOP_GET_STATUS: | |
4a5ce9ba JK |
1736 | err = loop_get_status_compat(lo, |
1737 | (struct compat_loop_info __user *)arg); | |
863d5b82 | 1738 | break; |
53d66608 | 1739 | case LOOP_SET_CAPACITY: |
863d5b82 DH |
1740 | case LOOP_CLR_FD: |
1741 | case LOOP_GET_STATUS64: | |
1742 | case LOOP_SET_STATUS64: | |
1743 | arg = (unsigned long) compat_ptr(arg); | |
d893ff86 | 1744 | /* fall through */ |
863d5b82 DH |
1745 | case LOOP_SET_FD: |
1746 | case LOOP_CHANGE_FD: | |
9fea4b39 | 1747 | case LOOP_SET_BLOCK_SIZE: |
bb214884 | 1748 | err = lo_ioctl(bdev, mode, cmd, arg); |
863d5b82 DH |
1749 | break; |
1750 | default: | |
1751 | err = -ENOIOCTLCMD; | |
1752 | break; | |
1753 | } | |
863d5b82 DH |
1754 | return err; |
1755 | } | |
1756 | #endif | |
1757 | ||
bb214884 | 1758 | static int lo_open(struct block_device *bdev, fmode_t mode) |
1da177e4 | 1759 | { |
770fe30a | 1760 | struct loop_device *lo; |
0a42e99b | 1761 | int err; |
770fe30a | 1762 | |
0a42e99b JK |
1763 | err = mutex_lock_killable(&loop_ctl_mutex); |
1764 | if (err) | |
1765 | return err; | |
770fe30a KS |
1766 | lo = bdev->bd_disk->private_data; |
1767 | if (!lo) { | |
1768 | err = -ENXIO; | |
1769 | goto out; | |
1770 | } | |
1da177e4 | 1771 | |
f8933667 | 1772 | atomic_inc(&lo->lo_refcnt); |
770fe30a | 1773 | out: |
0a42e99b | 1774 | mutex_unlock(&loop_ctl_mutex); |
770fe30a | 1775 | return err; |
1da177e4 LT |
1776 | } |
1777 | ||
967d1dc1 | 1778 | static void lo_release(struct gendisk *disk, fmode_t mode) |
1da177e4 | 1779 | { |
967d1dc1 | 1780 | struct loop_device *lo; |
1da177e4 | 1781 | |
0a42e99b | 1782 | mutex_lock(&loop_ctl_mutex); |
967d1dc1 | 1783 | lo = disk->private_data; |
f8933667 | 1784 | if (atomic_dec_return(&lo->lo_refcnt)) |
0a42e99b | 1785 | goto out_unlock; |
14f27939 MB |
1786 | |
1787 | if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { | |
a2505b79 JK |
1788 | if (lo->lo_state != Lo_bound) |
1789 | goto out_unlock; | |
1790 | lo->lo_state = Lo_rundown; | |
7ccd0791 | 1791 | mutex_unlock(&loop_ctl_mutex); |
14f27939 MB |
1792 | /* |
1793 | * In autoclear mode, stop the loop thread | |
1794 | * and remove configuration after last close. | |
1795 | */ | |
0da03cab | 1796 | __loop_clr_fd(lo, true); |
7ccd0791 | 1797 | return; |
43cade80 | 1798 | } else if (lo->lo_state == Lo_bound) { |
14f27939 MB |
1799 | /* |
1800 | * Otherwise keep thread (if running) and config, | |
1801 | * but flush possible ongoing bios in thread. | |
1802 | */ | |
43cade80 OS |
1803 | blk_mq_freeze_queue(lo->lo_queue); |
1804 | blk_mq_unfreeze_queue(lo->lo_queue); | |
14f27939 | 1805 | } |
96c58655 | 1806 | |
0a42e99b | 1807 | out_unlock: |
310ca162 | 1808 | mutex_unlock(&loop_ctl_mutex); |
ae665016 LT |
1809 | } |
1810 | ||
83d5cde4 | 1811 | static const struct block_device_operations lo_fops = { |
1da177e4 | 1812 | .owner = THIS_MODULE, |
bb214884 AV |
1813 | .open = lo_open, |
1814 | .release = lo_release, | |
1815 | .ioctl = lo_ioctl, | |
863d5b82 | 1816 | #ifdef CONFIG_COMPAT |
bb214884 | 1817 | .compat_ioctl = lo_compat_ioctl, |
863d5b82 | 1818 | #endif |
1da177e4 LT |
1819 | }; |
1820 | ||
1821 | /* | |
1822 | * And now the modules code and kernel interface. | |
1823 | */ | |
73285082 | 1824 | static int max_loop; |
5657a819 | 1825 | module_param(max_loop, int, 0444); |
a47653fc | 1826 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
5657a819 | 1827 | module_param(max_part, int, 0444); |
476a4813 | 1828 | MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
1da177e4 LT |
1829 | MODULE_LICENSE("GPL"); |
1830 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); | |
1831 | ||
1832 | int loop_register_transfer(struct loop_func_table *funcs) | |
1833 | { | |
1834 | unsigned int n = funcs->number; | |
1835 | ||
1836 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) | |
1837 | return -EINVAL; | |
1838 | xfer_funcs[n] = funcs; | |
1839 | return 0; | |
1840 | } | |
1841 | ||
34dd82af KS |
1842 | static int unregister_transfer_cb(int id, void *ptr, void *data) |
1843 | { | |
1844 | struct loop_device *lo = ptr; | |
1845 | struct loop_func_table *xfer = data; | |
1846 | ||
310ca162 | 1847 | mutex_lock(&loop_ctl_mutex); |
34dd82af KS |
1848 | if (lo->lo_encryption == xfer) |
1849 | loop_release_xfer(lo); | |
310ca162 | 1850 | mutex_unlock(&loop_ctl_mutex); |
34dd82af KS |
1851 | return 0; |
1852 | } | |
1853 | ||
1da177e4 LT |
1854 | int loop_unregister_transfer(int number) |
1855 | { | |
1856 | unsigned int n = number; | |
1da177e4 LT |
1857 | struct loop_func_table *xfer; |
1858 | ||
1859 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) | |
1860 | return -EINVAL; | |
1861 | ||
1862 | xfer_funcs[n] = NULL; | |
34dd82af | 1863 | idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer); |
1da177e4 LT |
1864 | return 0; |
1865 | } | |
1866 | ||
1867 | EXPORT_SYMBOL(loop_register_transfer); | |
1868 | EXPORT_SYMBOL(loop_unregister_transfer); | |
1869 | ||
fc17b653 | 1870 | static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, |
b5dd2f60 ML |
1871 | const struct blk_mq_queue_data *bd) |
1872 | { | |
1894e916 JA |
1873 | struct request *rq = bd->rq; |
1874 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
1875 | struct loop_device *lo = rq->q->queuedata; | |
b5dd2f60 | 1876 | |
1894e916 | 1877 | blk_mq_start_request(rq); |
b5dd2f60 | 1878 | |
f4aa4c7b | 1879 | if (lo->lo_state != Lo_bound) |
fc17b653 | 1880 | return BLK_STS_IOERR; |
f4aa4c7b | 1881 | |
1894e916 | 1882 | switch (req_op(rq)) { |
f0225cac CH |
1883 | case REQ_OP_FLUSH: |
1884 | case REQ_OP_DISCARD: | |
19372e27 | 1885 | case REQ_OP_WRITE_ZEROES: |
bc07c10a | 1886 | cmd->use_aio = false; |
f0225cac CH |
1887 | break; |
1888 | default: | |
1889 | cmd->use_aio = lo->use_dio; | |
1890 | break; | |
1891 | } | |
bc07c10a | 1892 | |
d4478e92 | 1893 | /* always use the first bio's css */ |
0b508bc9 | 1894 | #ifdef CONFIG_BLK_CGROUP |
db6638d7 DZ |
1895 | if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { |
1896 | cmd->css = &bio_blkcg(rq->bio)->css; | |
d4478e92 SL |
1897 | css_get(cmd->css); |
1898 | } else | |
1899 | #endif | |
1900 | cmd->css = NULL; | |
3989144f | 1901 | kthread_queue_work(&lo->worker, &cmd->work); |
b5dd2f60 | 1902 | |
fc17b653 | 1903 | return BLK_STS_OK; |
b5dd2f60 ML |
1904 | } |
1905 | ||
1906 | static void loop_handle_cmd(struct loop_cmd *cmd) | |
1907 | { | |
1894e916 JA |
1908 | struct request *rq = blk_mq_rq_from_pdu(cmd); |
1909 | const bool write = op_is_write(req_op(rq)); | |
1910 | struct loop_device *lo = rq->q->queuedata; | |
f4829a9b | 1911 | int ret = 0; |
b5dd2f60 | 1912 | |
f4829a9b CH |
1913 | if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { |
1914 | ret = -EIO; | |
b5dd2f60 | 1915 | goto failed; |
f4829a9b | 1916 | } |
b5dd2f60 | 1917 | |
1894e916 | 1918 | ret = do_req_filebacked(lo, rq); |
b5dd2f60 | 1919 | failed: |
bc07c10a | 1920 | /* complete non-aio request */ |
fe2cb290 CH |
1921 | if (!cmd->use_aio || ret) { |
1922 | cmd->ret = ret ? -EIO : 0; | |
1894e916 | 1923 | blk_mq_complete_request(rq); |
fe2cb290 | 1924 | } |
b5dd2f60 ML |
1925 | } |
1926 | ||
e03a3d7a | 1927 | static void loop_queue_work(struct kthread_work *work) |
b5dd2f60 ML |
1928 | { |
1929 | struct loop_cmd *cmd = | |
e03a3d7a | 1930 | container_of(work, struct loop_cmd, work); |
b5dd2f60 ML |
1931 | |
1932 | loop_handle_cmd(cmd); | |
1933 | } | |
1934 | ||
d6296d39 CH |
1935 | static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq, |
1936 | unsigned int hctx_idx, unsigned int numa_node) | |
b5dd2f60 ML |
1937 | { |
1938 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
1939 | ||
3989144f | 1940 | kthread_init_work(&cmd->work, loop_queue_work); |
b5dd2f60 ML |
1941 | return 0; |
1942 | } | |
1943 | ||
f363b089 | 1944 | static const struct blk_mq_ops loop_mq_ops = { |
b5dd2f60 | 1945 | .queue_rq = loop_queue_rq, |
b5dd2f60 | 1946 | .init_request = loop_init_request, |
fe2cb290 | 1947 | .complete = lo_complete_rq, |
b5dd2f60 ML |
1948 | }; |
1949 | ||
34dd82af | 1950 | static int loop_add(struct loop_device **l, int i) |
73285082 KC |
1951 | { |
1952 | struct loop_device *lo; | |
1953 | struct gendisk *disk; | |
34dd82af | 1954 | int err; |
73285082 | 1955 | |
68d740d7 | 1956 | err = -ENOMEM; |
73285082 | 1957 | lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
68d740d7 | 1958 | if (!lo) |
73285082 | 1959 | goto out; |
34dd82af | 1960 | |
ef7e7c82 MP |
1961 | lo->lo_state = Lo_unbound; |
1962 | ||
c718aa65 | 1963 | /* allocate id, if @id >= 0, we're requesting that specific id */ |
34dd82af | 1964 | if (i >= 0) { |
c718aa65 TH |
1965 | err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL); |
1966 | if (err == -ENOSPC) | |
34dd82af | 1967 | err = -EEXIST; |
34dd82af | 1968 | } else { |
c718aa65 | 1969 | err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL); |
34dd82af KS |
1970 | } |
1971 | if (err < 0) | |
1972 | goto out_free_dev; | |
c718aa65 | 1973 | i = err; |
73285082 | 1974 | |
183cfb57 | 1975 | err = -ENOMEM; |
b5dd2f60 ML |
1976 | lo->tag_set.ops = &loop_mq_ops; |
1977 | lo->tag_set.nr_hw_queues = 1; | |
1978 | lo->tag_set.queue_depth = 128; | |
1979 | lo->tag_set.numa_node = NUMA_NO_NODE; | |
1980 | lo->tag_set.cmd_size = sizeof(struct loop_cmd); | |
56d18f62 | 1981 | lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; |
b5dd2f60 ML |
1982 | lo->tag_set.driver_data = lo; |
1983 | ||
1984 | err = blk_mq_alloc_tag_set(&lo->tag_set); | |
1985 | if (err) | |
3ec981e3 | 1986 | goto out_free_idr; |
73285082 | 1987 | |
b5dd2f60 | 1988 | lo->lo_queue = blk_mq_init_queue(&lo->tag_set); |
38a3499f | 1989 | if (IS_ERR(lo->lo_queue)) { |
b5dd2f60 ML |
1990 | err = PTR_ERR(lo->lo_queue); |
1991 | goto out_cleanup_tags; | |
1992 | } | |
ef7e7c82 MP |
1993 | lo->lo_queue->queuedata = lo; |
1994 | ||
54bb0ade | 1995 | blk_queue_max_hw_sectors(lo->lo_queue, BLK_DEF_MAX_SECTORS); |
40326d8a | 1996 | |
5b5e20f4 | 1997 | /* |
40326d8a SL |
1998 | * By default, we do buffer IO, so it doesn't make sense to enable |
1999 | * merge because the I/O submitted to backing file is handled page by | |
2000 | * page. For directio mode, merge does help to dispatch bigger request | |
2001 | * to underlayer disk. We will enable merge once directio is enabled. | |
5b5e20f4 | 2002 | */ |
8b904b5b | 2003 | blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
5b5e20f4 | 2004 | |
7a649737 | 2005 | err = -ENOMEM; |
476a4813 | 2006 | disk = lo->lo_disk = alloc_disk(1 << part_shift); |
73285082 KC |
2007 | if (!disk) |
2008 | goto out_free_queue; | |
2009 | ||
e03c8dd1 KS |
2010 | /* |
2011 | * Disable partition scanning by default. The in-kernel partition | |
2012 | * scanning can be requested individually per-device during its | |
2013 | * setup. Userspace can always add and remove partitions from all | |
2014 | * devices. The needed partition minors are allocated from the | |
2015 | * extended minor space, the main loop device numbers will continue | |
2016 | * to match the loop minors, regardless of the number of partitions | |
2017 | * used. | |
2018 | * | |
2019 | * If max_part is given, partition scanning is globally enabled for | |
2020 | * all loop devices. The minors for the main loop devices will be | |
2021 | * multiples of max_part. | |
2022 | * | |
2023 | * Note: Global-for-all-devices, set-only-at-init, read-only module | |
2024 | * parameteters like 'max_loop' and 'max_part' make things needlessly | |
2025 | * complicated, are too static, inflexible and may surprise | |
2026 | * userspace tools. Parameters like this in general should be avoided. | |
2027 | */ | |
2028 | if (!part_shift) | |
2029 | disk->flags |= GENHD_FL_NO_PART_SCAN; | |
2030 | disk->flags |= GENHD_FL_EXT_DEVT; | |
f8933667 | 2031 | atomic_set(&lo->lo_refcnt, 0); |
73285082 | 2032 | lo->lo_number = i; |
73285082 KC |
2033 | spin_lock_init(&lo->lo_lock); |
2034 | disk->major = LOOP_MAJOR; | |
476a4813 | 2035 | disk->first_minor = i << part_shift; |
73285082 KC |
2036 | disk->fops = &lo_fops; |
2037 | disk->private_data = lo; | |
2038 | disk->queue = lo->lo_queue; | |
2039 | sprintf(disk->disk_name, "loop%d", i); | |
34dd82af KS |
2040 | add_disk(disk); |
2041 | *l = lo; | |
2042 | return lo->lo_number; | |
73285082 KC |
2043 | |
2044 | out_free_queue: | |
2045 | blk_cleanup_queue(lo->lo_queue); | |
b5dd2f60 ML |
2046 | out_cleanup_tags: |
2047 | blk_mq_free_tag_set(&lo->tag_set); | |
3ec981e3 MP |
2048 | out_free_idr: |
2049 | idr_remove(&loop_index_idr, i); | |
73285082 KC |
2050 | out_free_dev: |
2051 | kfree(lo); | |
2052 | out: | |
34dd82af | 2053 | return err; |
73285082 KC |
2054 | } |
2055 | ||
34dd82af | 2056 | static void loop_remove(struct loop_device *lo) |
1da177e4 | 2057 | { |
6cd18e71 | 2058 | del_gendisk(lo->lo_disk); |
0fa8ebdd | 2059 | blk_cleanup_queue(lo->lo_queue); |
b5dd2f60 | 2060 | blk_mq_free_tag_set(&lo->tag_set); |
73285082 | 2061 | put_disk(lo->lo_disk); |
73285082 KC |
2062 | kfree(lo); |
2063 | } | |
1da177e4 | 2064 | |
770fe30a KS |
2065 | static int find_free_cb(int id, void *ptr, void *data) |
2066 | { | |
2067 | struct loop_device *lo = ptr; | |
2068 | struct loop_device **l = data; | |
2069 | ||
2070 | if (lo->lo_state == Lo_unbound) { | |
2071 | *l = lo; | |
2072 | return 1; | |
2073 | } | |
2074 | return 0; | |
2075 | } | |
2076 | ||
34dd82af | 2077 | static int loop_lookup(struct loop_device **l, int i) |
a47653fc KC |
2078 | { |
2079 | struct loop_device *lo; | |
34dd82af | 2080 | int ret = -ENODEV; |
a47653fc | 2081 | |
770fe30a KS |
2082 | if (i < 0) { |
2083 | int err; | |
2084 | ||
2085 | err = idr_for_each(&loop_index_idr, &find_free_cb, &lo); | |
2086 | if (err == 1) { | |
2087 | *l = lo; | |
2088 | ret = lo->lo_number; | |
2089 | } | |
2090 | goto out; | |
a47653fc KC |
2091 | } |
2092 | ||
770fe30a | 2093 | /* lookup and return a specific i */ |
34dd82af | 2094 | lo = idr_find(&loop_index_idr, i); |
a47653fc | 2095 | if (lo) { |
34dd82af KS |
2096 | *l = lo; |
2097 | ret = lo->lo_number; | |
a47653fc | 2098 | } |
770fe30a | 2099 | out: |
34dd82af | 2100 | return ret; |
a47653fc KC |
2101 | } |
2102 | ||
73285082 KC |
2103 | static struct kobject *loop_probe(dev_t dev, int *part, void *data) |
2104 | { | |
705962cc | 2105 | struct loop_device *lo; |
07002e99 | 2106 | struct kobject *kobj; |
34dd82af | 2107 | int err; |
73285082 | 2108 | |
0a42e99b | 2109 | mutex_lock(&loop_ctl_mutex); |
34dd82af KS |
2110 | err = loop_lookup(&lo, MINOR(dev) >> part_shift); |
2111 | if (err < 0) | |
2112 | err = loop_add(&lo, MINOR(dev) >> part_shift); | |
2113 | if (err < 0) | |
a207f593 | 2114 | kobj = NULL; |
34dd82af | 2115 | else |
3079c22e | 2116 | kobj = get_disk_and_module(lo->lo_disk); |
0a42e99b | 2117 | mutex_unlock(&loop_ctl_mutex); |
73285082 KC |
2118 | |
2119 | *part = 0; | |
07002e99 | 2120 | return kobj; |
73285082 KC |
2121 | } |
2122 | ||
770fe30a KS |
2123 | static long loop_control_ioctl(struct file *file, unsigned int cmd, |
2124 | unsigned long parm) | |
2125 | { | |
2126 | struct loop_device *lo; | |
0a42e99b | 2127 | int ret; |
770fe30a | 2128 | |
0a42e99b JK |
2129 | ret = mutex_lock_killable(&loop_ctl_mutex); |
2130 | if (ret) | |
2131 | return ret; | |
2132 | ||
2133 | ret = -ENOSYS; | |
770fe30a KS |
2134 | switch (cmd) { |
2135 | case LOOP_CTL_ADD: | |
2136 | ret = loop_lookup(&lo, parm); | |
2137 | if (ret >= 0) { | |
2138 | ret = -EEXIST; | |
2139 | break; | |
2140 | } | |
2141 | ret = loop_add(&lo, parm); | |
2142 | break; | |
2143 | case LOOP_CTL_REMOVE: | |
2144 | ret = loop_lookup(&lo, parm); | |
2145 | if (ret < 0) | |
2146 | break; | |
770fe30a KS |
2147 | if (lo->lo_state != Lo_unbound) { |
2148 | ret = -EBUSY; | |
770fe30a KS |
2149 | break; |
2150 | } | |
f8933667 | 2151 | if (atomic_read(&lo->lo_refcnt) > 0) { |
770fe30a | 2152 | ret = -EBUSY; |
770fe30a KS |
2153 | break; |
2154 | } | |
2155 | lo->lo_disk->private_data = NULL; | |
770fe30a KS |
2156 | idr_remove(&loop_index_idr, lo->lo_number); |
2157 | loop_remove(lo); | |
2158 | break; | |
2159 | case LOOP_CTL_GET_FREE: | |
2160 | ret = loop_lookup(&lo, -1); | |
2161 | if (ret >= 0) | |
2162 | break; | |
2163 | ret = loop_add(&lo, -1); | |
2164 | } | |
0a42e99b | 2165 | mutex_unlock(&loop_ctl_mutex); |
770fe30a KS |
2166 | |
2167 | return ret; | |
2168 | } | |
2169 | ||
2170 | static const struct file_operations loop_ctl_fops = { | |
2171 | .open = nonseekable_open, | |
2172 | .unlocked_ioctl = loop_control_ioctl, | |
2173 | .compat_ioctl = loop_control_ioctl, | |
2174 | .owner = THIS_MODULE, | |
2175 | .llseek = noop_llseek, | |
2176 | }; | |
2177 | ||
2178 | static struct miscdevice loop_misc = { | |
2179 | .minor = LOOP_CTRL_MINOR, | |
2180 | .name = "loop-control", | |
2181 | .fops = &loop_ctl_fops, | |
2182 | }; | |
2183 | ||
2184 | MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR); | |
2185 | MODULE_ALIAS("devname:loop-control"); | |
2186 | ||
73285082 KC |
2187 | static int __init loop_init(void) |
2188 | { | |
a47653fc KC |
2189 | int i, nr; |
2190 | unsigned long range; | |
34dd82af | 2191 | struct loop_device *lo; |
770fe30a | 2192 | int err; |
a47653fc | 2193 | |
476a4813 | 2194 | part_shift = 0; |
ac04fee0 | 2195 | if (max_part > 0) { |
476a4813 LV |
2196 | part_shift = fls(max_part); |
2197 | ||
ac04fee0 NK |
2198 | /* |
2199 | * Adjust max_part according to part_shift as it is exported | |
2200 | * to user space so that user can decide correct minor number | |
2201 | * if [s]he want to create more devices. | |
2202 | * | |
2203 | * Note that -1 is required because partition 0 is reserved | |
2204 | * for the whole disk. | |
2205 | */ | |
2206 | max_part = (1UL << part_shift) - 1; | |
2207 | } | |
2208 | ||
b1a66504 GC |
2209 | if ((1UL << part_shift) > DISK_MAX_PARTS) { |
2210 | err = -EINVAL; | |
a8c1d064 | 2211 | goto err_out; |
b1a66504 | 2212 | } |
78f4bb36 | 2213 | |
b1a66504 GC |
2214 | if (max_loop > 1UL << (MINORBITS - part_shift)) { |
2215 | err = -EINVAL; | |
a8c1d064 | 2216 | goto err_out; |
b1a66504 | 2217 | } |
1da177e4 | 2218 | |
d134b00b KS |
2219 | /* |
2220 | * If max_loop is specified, create that many devices upfront. | |
2221 | * This also becomes a hard limit. If max_loop is not specified, | |
2222 | * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module | |
2223 | * init time. Loop devices can be requested on-demand with the | |
2224 | * /dev/loop-control interface, or be instantiated by accessing | |
2225 | * a 'dead' device node. | |
2226 | */ | |
73285082 | 2227 | if (max_loop) { |
a47653fc | 2228 | nr = max_loop; |
a1c15c59 | 2229 | range = max_loop << part_shift; |
a47653fc | 2230 | } else { |
d134b00b | 2231 | nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; |
a1c15c59 | 2232 | range = 1UL << MINORBITS; |
a47653fc KC |
2233 | } |
2234 | ||
a8c1d064 AV |
2235 | err = misc_register(&loop_misc); |
2236 | if (err < 0) | |
2237 | goto err_out; | |
2238 | ||
2239 | ||
b1a66504 GC |
2240 | if (register_blkdev(LOOP_MAJOR, "loop")) { |
2241 | err = -EIO; | |
2242 | goto misc_out; | |
2243 | } | |
1da177e4 | 2244 | |
a47653fc KC |
2245 | blk_register_region(MKDEV(LOOP_MAJOR, 0), range, |
2246 | THIS_MODULE, loop_probe, NULL, NULL); | |
2247 | ||
d134b00b | 2248 | /* pre-create number of devices given by config or max_loop */ |
0a42e99b | 2249 | mutex_lock(&loop_ctl_mutex); |
34dd82af KS |
2250 | for (i = 0; i < nr; i++) |
2251 | loop_add(&lo, i); | |
0a42e99b | 2252 | mutex_unlock(&loop_ctl_mutex); |
34dd82af | 2253 | |
73285082 | 2254 | printk(KERN_INFO "loop: module loaded\n"); |
1da177e4 | 2255 | return 0; |
b1a66504 GC |
2256 | |
2257 | misc_out: | |
2258 | misc_deregister(&loop_misc); | |
a8c1d064 | 2259 | err_out: |
b1a66504 | 2260 | return err; |
34dd82af | 2261 | } |
a47653fc | 2262 | |
34dd82af KS |
2263 | static int loop_exit_cb(int id, void *ptr, void *data) |
2264 | { | |
2265 | struct loop_device *lo = ptr; | |
a47653fc | 2266 | |
34dd82af KS |
2267 | loop_remove(lo); |
2268 | return 0; | |
1da177e4 LT |
2269 | } |
2270 | ||
73285082 | 2271 | static void __exit loop_exit(void) |
1da177e4 | 2272 | { |
a47653fc | 2273 | unsigned long range; |
1da177e4 | 2274 | |
a1c15c59 | 2275 | range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; |
a47653fc | 2276 | |
34dd82af | 2277 | idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); |
34dd82af | 2278 | idr_destroy(&loop_index_idr); |
73285082 | 2279 | |
a47653fc | 2280 | blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); |
00d59405 | 2281 | unregister_blkdev(LOOP_MAJOR, "loop"); |
770fe30a KS |
2282 | |
2283 | misc_deregister(&loop_misc); | |
1da177e4 LT |
2284 | } |
2285 | ||
2286 | module_init(loop_init); | |
2287 | module_exit(loop_exit); | |
2288 | ||
2289 | #ifndef MODULE | |
2290 | static int __init max_loop_setup(char *str) | |
2291 | { | |
2292 | max_loop = simple_strtol(str, NULL, 0); | |
2293 | return 1; | |
2294 | } | |
2295 | ||
2296 | __setup("max_loop=", max_loop_setup); | |
2297 | #endif |