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> |
83a87611 | 79 | #include "loop.h" |
1da177e4 LT |
80 | |
81 | #include <asm/uaccess.h> | |
82 | ||
34dd82af KS |
83 | static DEFINE_IDR(loop_index_idr); |
84 | static DEFINE_MUTEX(loop_index_mutex); | |
1da177e4 | 85 | |
476a4813 LV |
86 | static int max_part; |
87 | static int part_shift; | |
88 | ||
1da177e4 LT |
89 | static int transfer_xor(struct loop_device *lo, int cmd, |
90 | struct page *raw_page, unsigned raw_off, | |
91 | struct page *loop_page, unsigned loop_off, | |
92 | int size, sector_t real_block) | |
93 | { | |
cfd8005c CW |
94 | char *raw_buf = kmap_atomic(raw_page) + raw_off; |
95 | char *loop_buf = kmap_atomic(loop_page) + loop_off; | |
1da177e4 LT |
96 | char *in, *out, *key; |
97 | int i, keysize; | |
98 | ||
99 | if (cmd == READ) { | |
100 | in = raw_buf; | |
101 | out = loop_buf; | |
102 | } else { | |
103 | in = loop_buf; | |
104 | out = raw_buf; | |
105 | } | |
106 | ||
107 | key = lo->lo_encrypt_key; | |
108 | keysize = lo->lo_encrypt_key_size; | |
109 | for (i = 0; i < size; i++) | |
110 | *out++ = *in++ ^ key[(i & 511) % keysize]; | |
111 | ||
cfd8005c CW |
112 | kunmap_atomic(loop_buf); |
113 | kunmap_atomic(raw_buf); | |
1da177e4 LT |
114 | cond_resched(); |
115 | return 0; | |
116 | } | |
117 | ||
118 | static int xor_init(struct loop_device *lo, const struct loop_info64 *info) | |
119 | { | |
120 | if (unlikely(info->lo_encrypt_key_size <= 0)) | |
121 | return -EINVAL; | |
122 | return 0; | |
123 | } | |
124 | ||
125 | static struct loop_func_table none_funcs = { | |
126 | .number = LO_CRYPT_NONE, | |
aa4d8616 | 127 | }; |
1da177e4 LT |
128 | |
129 | static struct loop_func_table xor_funcs = { | |
130 | .number = LO_CRYPT_XOR, | |
131 | .transfer = transfer_xor, | |
132 | .init = xor_init | |
aa4d8616 | 133 | }; |
1da177e4 LT |
134 | |
135 | /* xfer_funcs[0] is special - its release function is never called */ | |
136 | static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { | |
137 | &none_funcs, | |
138 | &xor_funcs | |
139 | }; | |
140 | ||
7035b5df | 141 | static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) |
1da177e4 | 142 | { |
b7a1da69 | 143 | loff_t loopsize; |
1da177e4 LT |
144 | |
145 | /* Compute loopsize in bytes */ | |
b7a1da69 GC |
146 | loopsize = i_size_read(file->f_mapping->host); |
147 | if (offset > 0) | |
148 | loopsize -= offset; | |
149 | /* offset is beyond i_size, weird but possible */ | |
7035b5df DM |
150 | if (loopsize < 0) |
151 | return 0; | |
1da177e4 | 152 | |
7035b5df DM |
153 | if (sizelimit > 0 && sizelimit < loopsize) |
154 | loopsize = sizelimit; | |
1da177e4 LT |
155 | /* |
156 | * Unfortunately, if we want to do I/O on the device, | |
157 | * the number of 512-byte sectors has to fit into a sector_t. | |
158 | */ | |
159 | return loopsize >> 9; | |
160 | } | |
161 | ||
7035b5df DM |
162 | static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
163 | { | |
164 | return get_size(lo->lo_offset, lo->lo_sizelimit, file); | |
165 | } | |
166 | ||
1da177e4 | 167 | static int |
7035b5df | 168 | figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) |
1da177e4 | 169 | { |
7035b5df | 170 | loff_t size = get_size(offset, sizelimit, lo->lo_backing_file); |
1da177e4 | 171 | sector_t x = (sector_t)size; |
7b0576a3 | 172 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
173 | |
174 | if (unlikely((loff_t)x != size)) | |
175 | return -EFBIG; | |
7035b5df DM |
176 | if (lo->lo_offset != offset) |
177 | lo->lo_offset = offset; | |
178 | if (lo->lo_sizelimit != sizelimit) | |
179 | lo->lo_sizelimit = sizelimit; | |
73285082 | 180 | set_capacity(lo->lo_disk, x); |
7b0576a3 GC |
181 | bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9); |
182 | /* let user-space know about the new size */ | |
183 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
7035b5df | 184 | return 0; |
1da177e4 LT |
185 | } |
186 | ||
187 | static inline int | |
188 | lo_do_transfer(struct loop_device *lo, int cmd, | |
189 | struct page *rpage, unsigned roffs, | |
190 | struct page *lpage, unsigned loffs, | |
191 | int size, sector_t rblock) | |
192 | { | |
aa4d8616 CH |
193 | int ret; |
194 | ||
195 | ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); | |
196 | if (likely(!ret)) | |
1da177e4 LT |
197 | return 0; |
198 | ||
aa4d8616 CH |
199 | printk_ratelimited(KERN_ERR |
200 | "loop: Transfer error at byte offset %llu, length %i.\n", | |
201 | (unsigned long long)rblock << 9, size); | |
202 | return ret; | |
1da177e4 LT |
203 | } |
204 | ||
aa4d8616 | 205 | static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) |
1da177e4 | 206 | { |
aa4d8616 | 207 | struct iov_iter i; |
1da177e4 | 208 | ssize_t bw; |
283e7e5d | 209 | |
aa4d8616 | 210 | iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len); |
1da177e4 | 211 | |
03d95eb2 | 212 | file_start_write(file); |
aa4d8616 | 213 | bw = vfs_iter_write(file, &i, ppos); |
03d95eb2 | 214 | file_end_write(file); |
aa4d8616 CH |
215 | |
216 | if (likely(bw == bvec->bv_len)) | |
1da177e4 | 217 | return 0; |
aa4d8616 CH |
218 | |
219 | printk_ratelimited(KERN_ERR | |
220 | "loop: Write error at byte offset %llu, length %i.\n", | |
221 | (unsigned long long)*ppos, bvec->bv_len); | |
1da177e4 LT |
222 | if (bw >= 0) |
223 | bw = -EIO; | |
224 | return bw; | |
225 | } | |
226 | ||
aa4d8616 CH |
227 | static int lo_write_simple(struct loop_device *lo, struct request *rq, |
228 | loff_t pos) | |
1da177e4 | 229 | { |
aa4d8616 CH |
230 | struct bio_vec bvec; |
231 | struct req_iterator iter; | |
232 | int ret = 0; | |
233 | ||
234 | rq_for_each_segment(bvec, rq, iter) { | |
235 | ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos); | |
236 | if (ret < 0) | |
237 | break; | |
238 | cond_resched(); | |
239 | } | |
240 | ||
241 | return ret; | |
1da177e4 LT |
242 | } |
243 | ||
aa4d8616 | 244 | /* |
456be148 CH |
245 | * This is the slow, transforming version that needs to double buffer the |
246 | * data as it cannot do the transformations in place without having direct | |
247 | * access to the destination pages of the backing file. | |
1da177e4 | 248 | */ |
aa4d8616 CH |
249 | static int lo_write_transfer(struct loop_device *lo, struct request *rq, |
250 | loff_t pos) | |
1da177e4 | 251 | { |
aa4d8616 | 252 | struct bio_vec bvec, b; |
30112013 | 253 | struct req_iterator iter; |
aa4d8616 | 254 | struct page *page; |
7988613b | 255 | int ret = 0; |
1da177e4 | 256 | |
aa4d8616 CH |
257 | page = alloc_page(GFP_NOIO); |
258 | if (unlikely(!page)) | |
259 | return -ENOMEM; | |
456be148 | 260 | |
30112013 | 261 | rq_for_each_segment(bvec, rq, iter) { |
aa4d8616 CH |
262 | ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page, |
263 | bvec.bv_offset, bvec.bv_len, pos >> 9); | |
264 | if (unlikely(ret)) | |
265 | break; | |
266 | ||
267 | b.bv_page = page; | |
268 | b.bv_offset = 0; | |
269 | b.bv_len = bvec.bv_len; | |
270 | ret = lo_write_bvec(lo->lo_backing_file, &b, &pos); | |
1da177e4 LT |
271 | if (ret < 0) |
272 | break; | |
1da177e4 | 273 | } |
aa4d8616 CH |
274 | |
275 | __free_page(page); | |
1da177e4 | 276 | return ret; |
1da177e4 LT |
277 | } |
278 | ||
aa4d8616 CH |
279 | static int lo_read_simple(struct loop_device *lo, struct request *rq, |
280 | loff_t pos) | |
1da177e4 | 281 | { |
aa4d8616 CH |
282 | struct bio_vec bvec; |
283 | struct req_iterator iter; | |
284 | struct iov_iter i; | |
285 | ssize_t len; | |
1da177e4 | 286 | |
aa4d8616 CH |
287 | rq_for_each_segment(bvec, rq, iter) { |
288 | iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len); | |
289 | len = vfs_iter_read(lo->lo_backing_file, &i, &pos); | |
290 | if (len < 0) | |
291 | return len; | |
1da177e4 | 292 | |
aa4d8616 | 293 | flush_dcache_page(bvec.bv_page); |
fd582140 | 294 | |
aa4d8616 CH |
295 | if (len != bvec.bv_len) { |
296 | struct bio *bio; | |
1da177e4 | 297 | |
aa4d8616 CH |
298 | __rq_for_each_bio(bio, rq) |
299 | zero_fill_bio(bio); | |
300 | break; | |
301 | } | |
302 | cond_resched(); | |
303 | } | |
304 | ||
305 | return 0; | |
fd582140 JA |
306 | } |
307 | ||
aa4d8616 CH |
308 | static int lo_read_transfer(struct loop_device *lo, struct request *rq, |
309 | loff_t pos) | |
1da177e4 | 310 | { |
aa4d8616 CH |
311 | struct bio_vec bvec, b; |
312 | struct req_iterator iter; | |
313 | struct iov_iter i; | |
314 | struct page *page; | |
315 | ssize_t len; | |
316 | int ret = 0; | |
1da177e4 | 317 | |
aa4d8616 CH |
318 | page = alloc_page(GFP_NOIO); |
319 | if (unlikely(!page)) | |
320 | return -ENOMEM; | |
fd582140 | 321 | |
aa4d8616 CH |
322 | rq_for_each_segment(bvec, rq, iter) { |
323 | loff_t offset = pos; | |
fd582140 | 324 | |
aa4d8616 CH |
325 | b.bv_page = page; |
326 | b.bv_offset = 0; | |
327 | b.bv_len = bvec.bv_len; | |
fd582140 | 328 | |
aa4d8616 CH |
329 | iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len); |
330 | len = vfs_iter_read(lo->lo_backing_file, &i, &pos); | |
331 | if (len < 0) { | |
332 | ret = len; | |
333 | goto out_free_page; | |
334 | } | |
1da177e4 | 335 | |
aa4d8616 CH |
336 | ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page, |
337 | bvec.bv_offset, len, offset >> 9); | |
338 | if (ret) | |
339 | goto out_free_page; | |
1da177e4 | 340 | |
aa4d8616 | 341 | flush_dcache_page(bvec.bv_page); |
306df071 | 342 | |
aa4d8616 | 343 | if (len != bvec.bv_len) { |
30112013 ML |
344 | struct bio *bio; |
345 | ||
346 | __rq_for_each_bio(bio, rq) | |
347 | zero_fill_bio(bio); | |
1da177e4 | 348 | break; |
306df071 | 349 | } |
1da177e4 | 350 | } |
aa4d8616 CH |
351 | |
352 | ret = 0; | |
353 | out_free_page: | |
354 | __free_page(page); | |
355 | return ret; | |
1da177e4 LT |
356 | } |
357 | ||
cf655d95 ML |
358 | static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos) |
359 | { | |
360 | /* | |
361 | * We use punch hole to reclaim the free space used by the | |
362 | * image a.k.a. discard. However we do not support discard if | |
363 | * encryption is enabled, because it may give an attacker | |
364 | * useful information. | |
365 | */ | |
366 | struct file *file = lo->lo_backing_file; | |
367 | int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE; | |
368 | int ret; | |
369 | ||
370 | if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { | |
371 | ret = -EOPNOTSUPP; | |
372 | goto out; | |
373 | } | |
374 | ||
375 | ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); | |
376 | if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) | |
377 | ret = -EIO; | |
378 | out: | |
379 | return ret; | |
380 | } | |
381 | ||
382 | static int lo_req_flush(struct loop_device *lo, struct request *rq) | |
383 | { | |
384 | struct file *file = lo->lo_backing_file; | |
385 | int ret = vfs_fsync(file, 0); | |
386 | if (unlikely(ret && ret != -EINVAL)) | |
387 | ret = -EIO; | |
388 | ||
389 | return ret; | |
390 | } | |
391 | ||
30112013 | 392 | static int do_req_filebacked(struct loop_device *lo, struct request *rq) |
1da177e4 LT |
393 | { |
394 | loff_t pos; | |
395 | int ret; | |
396 | ||
30112013 | 397 | pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; |
68db1961 | 398 | |
30112013 | 399 | if (rq->cmd_flags & REQ_WRITE) { |
cf655d95 ML |
400 | if (rq->cmd_flags & REQ_FLUSH) |
401 | ret = lo_req_flush(lo, rq); | |
af65aa8e | 402 | else if (rq->cmd_flags & REQ_DISCARD) |
cf655d95 | 403 | ret = lo_discard(lo, rq, pos); |
aa4d8616 CH |
404 | else if (lo->transfer) |
405 | ret = lo_write_transfer(lo, rq, pos); | |
af65aa8e | 406 | else |
aa4d8616 CH |
407 | ret = lo_write_simple(lo, rq, pos); |
408 | ||
409 | } else { | |
410 | if (lo->transfer) | |
411 | ret = lo_read_transfer(lo, rq, pos); | |
412 | else | |
413 | ret = lo_read_simple(lo, rq, pos); | |
414 | } | |
68db1961 | 415 | |
1da177e4 LT |
416 | return ret; |
417 | } | |
418 | ||
1da177e4 LT |
419 | struct switch_request { |
420 | struct file *file; | |
421 | struct completion wait; | |
422 | }; | |
423 | ||
1da177e4 | 424 | /* |
b5dd2f60 | 425 | * Do the actual switch; called from the BIO completion routine |
1da177e4 | 426 | */ |
b5dd2f60 | 427 | static void do_loop_switch(struct loop_device *lo, struct switch_request *p) |
1da177e4 | 428 | { |
b5dd2f60 ML |
429 | struct file *file = p->file; |
430 | struct file *old_file = lo->lo_backing_file; | |
431 | struct address_space *mapping; | |
35a82d1a | 432 | |
b5dd2f60 ML |
433 | /* if no new file, only flush of queued bios requested */ |
434 | if (!file) | |
435 | return; | |
1da177e4 | 436 | |
b5dd2f60 ML |
437 | mapping = file->f_mapping; |
438 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); | |
439 | lo->lo_backing_file = file; | |
440 | lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ? | |
441 | mapping->host->i_bdev->bd_block_size : PAGE_SIZE; | |
442 | lo->old_gfp_mask = mapping_gfp_mask(mapping); | |
443 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
1da177e4 LT |
444 | } |
445 | ||
446 | /* | |
447 | * loop_switch performs the hard work of switching a backing store. | |
448 | * First it needs to flush existing IO, it does this by sending a magic | |
449 | * BIO down the pipe. The completion of this BIO does the actual switch. | |
450 | */ | |
451 | static int loop_switch(struct loop_device *lo, struct file *file) | |
452 | { | |
453 | struct switch_request w; | |
b5dd2f60 | 454 | |
1da177e4 | 455 | w.file = file; |
b5dd2f60 ML |
456 | |
457 | /* freeze queue and wait for completion of scheduled requests */ | |
458 | blk_mq_freeze_queue(lo->lo_queue); | |
459 | ||
460 | /* do the switch action */ | |
461 | do_loop_switch(lo, &w); | |
462 | ||
463 | /* unfreeze */ | |
464 | blk_mq_unfreeze_queue(lo->lo_queue); | |
465 | ||
1da177e4 LT |
466 | return 0; |
467 | } | |
468 | ||
14f27939 MB |
469 | /* |
470 | * Helper to flush the IOs in loop, but keeping loop thread running | |
471 | */ | |
472 | static int loop_flush(struct loop_device *lo) | |
473 | { | |
14f27939 MB |
474 | return loop_switch(lo, NULL); |
475 | } | |
476 | ||
06f0e9e6 ML |
477 | static void loop_reread_partitions(struct loop_device *lo, |
478 | struct block_device *bdev) | |
479 | { | |
480 | int rc; | |
481 | ||
482 | /* | |
483 | * bd_mutex has been held already in release path, so don't | |
484 | * acquire it if this function is called in such case. | |
485 | * | |
486 | * If the reread partition isn't from release path, lo_refcnt | |
487 | * must be at least one and it can only become zero when the | |
488 | * current holder is released. | |
489 | */ | |
490 | if (!atomic_read(&lo->lo_refcnt)) | |
491 | rc = __blkdev_reread_part(bdev); | |
492 | else | |
493 | rc = blkdev_reread_part(bdev); | |
494 | if (rc) | |
495 | pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", | |
496 | __func__, lo->lo_number, lo->lo_file_name, rc); | |
497 | } | |
498 | ||
1da177e4 LT |
499 | /* |
500 | * loop_change_fd switched the backing store of a loopback device to | |
501 | * a new file. This is useful for operating system installers to free up | |
502 | * the original file and in High Availability environments to switch to | |
503 | * an alternative location for the content in case of server meltdown. | |
504 | * This can only work if the loop device is used read-only, and if the | |
505 | * new backing store is the same size and type as the old backing store. | |
506 | */ | |
bb214884 AV |
507 | static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
508 | unsigned int arg) | |
1da177e4 LT |
509 | { |
510 | struct file *file, *old_file; | |
511 | struct inode *inode; | |
512 | int error; | |
513 | ||
514 | error = -ENXIO; | |
515 | if (lo->lo_state != Lo_bound) | |
516 | goto out; | |
517 | ||
518 | /* the loop device has to be read-only */ | |
519 | error = -EINVAL; | |
520 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) | |
521 | goto out; | |
522 | ||
523 | error = -EBADF; | |
524 | file = fget(arg); | |
525 | if (!file) | |
526 | goto out; | |
527 | ||
528 | inode = file->f_mapping->host; | |
529 | old_file = lo->lo_backing_file; | |
530 | ||
531 | error = -EINVAL; | |
532 | ||
533 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
534 | goto out_putf; | |
535 | ||
1da177e4 LT |
536 | /* size of the new backing store needs to be the same */ |
537 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) | |
538 | goto out_putf; | |
539 | ||
540 | /* and ... switch */ | |
541 | error = loop_switch(lo, file); | |
542 | if (error) | |
543 | goto out_putf; | |
544 | ||
545 | fput(old_file); | |
e03c8dd1 | 546 | if (lo->lo_flags & LO_FLAGS_PARTSCAN) |
06f0e9e6 | 547 | loop_reread_partitions(lo, bdev); |
1da177e4 LT |
548 | return 0; |
549 | ||
550 | out_putf: | |
551 | fput(file); | |
552 | out: | |
553 | return error; | |
554 | } | |
555 | ||
556 | static inline int is_loop_device(struct file *file) | |
557 | { | |
558 | struct inode *i = file->f_mapping->host; | |
559 | ||
560 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; | |
561 | } | |
562 | ||
ee862730 MB |
563 | /* loop sysfs attributes */ |
564 | ||
565 | static ssize_t loop_attr_show(struct device *dev, char *page, | |
566 | ssize_t (*callback)(struct loop_device *, char *)) | |
567 | { | |
34dd82af KS |
568 | struct gendisk *disk = dev_to_disk(dev); |
569 | struct loop_device *lo = disk->private_data; | |
ee862730 | 570 | |
34dd82af | 571 | return callback(lo, page); |
ee862730 MB |
572 | } |
573 | ||
574 | #define LOOP_ATTR_RO(_name) \ | |
575 | static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ | |
576 | static ssize_t loop_attr_do_show_##_name(struct device *d, \ | |
577 | struct device_attribute *attr, char *b) \ | |
578 | { \ | |
579 | return loop_attr_show(d, b, loop_attr_##_name##_show); \ | |
580 | } \ | |
581 | static struct device_attribute loop_attr_##_name = \ | |
582 | __ATTR(_name, S_IRUGO, loop_attr_do_show_##_name, NULL); | |
583 | ||
584 | static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) | |
585 | { | |
586 | ssize_t ret; | |
587 | char *p = NULL; | |
588 | ||
05eb0f25 | 589 | spin_lock_irq(&lo->lo_lock); |
ee862730 | 590 | if (lo->lo_backing_file) |
9bf39ab2 | 591 | p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1); |
05eb0f25 | 592 | spin_unlock_irq(&lo->lo_lock); |
ee862730 MB |
593 | |
594 | if (IS_ERR_OR_NULL(p)) | |
595 | ret = PTR_ERR(p); | |
596 | else { | |
597 | ret = strlen(p); | |
598 | memmove(buf, p, ret); | |
599 | buf[ret++] = '\n'; | |
600 | buf[ret] = 0; | |
601 | } | |
602 | ||
603 | return ret; | |
604 | } | |
605 | ||
606 | static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) | |
607 | { | |
608 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); | |
609 | } | |
610 | ||
611 | static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) | |
612 | { | |
613 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); | |
614 | } | |
615 | ||
616 | static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) | |
617 | { | |
618 | int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); | |
619 | ||
620 | return sprintf(buf, "%s\n", autoclear ? "1" : "0"); | |
621 | } | |
622 | ||
e03c8dd1 KS |
623 | static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf) |
624 | { | |
625 | int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN); | |
626 | ||
627 | return sprintf(buf, "%s\n", partscan ? "1" : "0"); | |
628 | } | |
629 | ||
ee862730 MB |
630 | LOOP_ATTR_RO(backing_file); |
631 | LOOP_ATTR_RO(offset); | |
632 | LOOP_ATTR_RO(sizelimit); | |
633 | LOOP_ATTR_RO(autoclear); | |
e03c8dd1 | 634 | LOOP_ATTR_RO(partscan); |
ee862730 MB |
635 | |
636 | static struct attribute *loop_attrs[] = { | |
637 | &loop_attr_backing_file.attr, | |
638 | &loop_attr_offset.attr, | |
639 | &loop_attr_sizelimit.attr, | |
640 | &loop_attr_autoclear.attr, | |
e03c8dd1 | 641 | &loop_attr_partscan.attr, |
ee862730 MB |
642 | NULL, |
643 | }; | |
644 | ||
645 | static struct attribute_group loop_attribute_group = { | |
646 | .name = "loop", | |
647 | .attrs= loop_attrs, | |
648 | }; | |
649 | ||
650 | static int loop_sysfs_init(struct loop_device *lo) | |
651 | { | |
652 | return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, | |
653 | &loop_attribute_group); | |
654 | } | |
655 | ||
656 | static void loop_sysfs_exit(struct loop_device *lo) | |
657 | { | |
658 | sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, | |
659 | &loop_attribute_group); | |
660 | } | |
661 | ||
dfaa2ef6 LC |
662 | static void loop_config_discard(struct loop_device *lo) |
663 | { | |
664 | struct file *file = lo->lo_backing_file; | |
665 | struct inode *inode = file->f_mapping->host; | |
666 | struct request_queue *q = lo->lo_queue; | |
667 | ||
668 | /* | |
669 | * We use punch hole to reclaim the free space used by the | |
12a64d2f | 670 | * image a.k.a. discard. However we do not support discard if |
dfaa2ef6 LC |
671 | * encryption is enabled, because it may give an attacker |
672 | * useful information. | |
673 | */ | |
674 | if ((!file->f_op->fallocate) || | |
675 | lo->lo_encrypt_key_size) { | |
676 | q->limits.discard_granularity = 0; | |
677 | q->limits.discard_alignment = 0; | |
678 | q->limits.max_discard_sectors = 0; | |
679 | q->limits.discard_zeroes_data = 0; | |
680 | queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q); | |
681 | return; | |
682 | } | |
683 | ||
684 | q->limits.discard_granularity = inode->i_sb->s_blocksize; | |
dfaf3c03 | 685 | q->limits.discard_alignment = 0; |
dfaa2ef6 LC |
686 | q->limits.max_discard_sectors = UINT_MAX >> 9; |
687 | q->limits.discard_zeroes_data = 1; | |
688 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); | |
689 | } | |
690 | ||
bb214884 | 691 | static int loop_set_fd(struct loop_device *lo, fmode_t mode, |
1da177e4 LT |
692 | struct block_device *bdev, unsigned int arg) |
693 | { | |
694 | struct file *file, *f; | |
695 | struct inode *inode; | |
696 | struct address_space *mapping; | |
697 | unsigned lo_blocksize; | |
698 | int lo_flags = 0; | |
699 | int error; | |
700 | loff_t size; | |
701 | ||
702 | /* This is safe, since we have a reference from open(). */ | |
703 | __module_get(THIS_MODULE); | |
704 | ||
705 | error = -EBADF; | |
706 | file = fget(arg); | |
707 | if (!file) | |
708 | goto out; | |
709 | ||
710 | error = -EBUSY; | |
711 | if (lo->lo_state != Lo_unbound) | |
712 | goto out_putf; | |
713 | ||
714 | /* Avoid recursion */ | |
715 | f = file; | |
716 | while (is_loop_device(f)) { | |
717 | struct loop_device *l; | |
718 | ||
bb214884 | 719 | if (f->f_mapping->host->i_bdev == bdev) |
1da177e4 LT |
720 | goto out_putf; |
721 | ||
722 | l = f->f_mapping->host->i_bdev->bd_disk->private_data; | |
723 | if (l->lo_state == Lo_unbound) { | |
724 | error = -EINVAL; | |
725 | goto out_putf; | |
726 | } | |
727 | f = l->lo_backing_file; | |
728 | } | |
729 | ||
730 | mapping = file->f_mapping; | |
731 | inode = mapping->host; | |
732 | ||
1da177e4 | 733 | error = -EINVAL; |
456be148 CH |
734 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
735 | goto out_putf; | |
1da177e4 | 736 | |
456be148 | 737 | if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || |
283e7e5d | 738 | !file->f_op->write_iter) |
456be148 | 739 | lo_flags |= LO_FLAGS_READ_ONLY; |
ba52de12 | 740 | |
456be148 CH |
741 | lo_blocksize = S_ISBLK(inode->i_mode) ? |
742 | inode->i_bdev->bd_block_size : PAGE_SIZE; | |
1da177e4 | 743 | |
456be148 | 744 | error = -EFBIG; |
1da177e4 | 745 | size = get_loop_size(lo, file); |
456be148 | 746 | if ((loff_t)(sector_t)size != size) |
1da177e4 | 747 | goto out_putf; |
f4aa4c7b ML |
748 | error = -ENOMEM; |
749 | lo->wq = alloc_workqueue("kloopd%d", | |
4d4e41ae | 750 | WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 16, |
f4aa4c7b ML |
751 | lo->lo_number); |
752 | if (!lo->wq) | |
753 | goto out_putf; | |
1da177e4 | 754 | |
456be148 | 755 | error = 0; |
1da177e4 LT |
756 | |
757 | set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); | |
758 | ||
759 | lo->lo_blocksize = lo_blocksize; | |
760 | lo->lo_device = bdev; | |
761 | lo->lo_flags = lo_flags; | |
762 | lo->lo_backing_file = file; | |
aa4d8616 | 763 | lo->transfer = NULL; |
1da177e4 LT |
764 | lo->ioctl = NULL; |
765 | lo->lo_sizelimit = 0; | |
766 | lo->old_gfp_mask = mapping_gfp_mask(mapping); | |
767 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); | |
768 | ||
68db1961 | 769 | if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
4913efe4 | 770 | blk_queue_flush(lo->lo_queue, REQ_FLUSH); |
68db1961 | 771 | |
73285082 | 772 | set_capacity(lo->lo_disk, size); |
1da177e4 | 773 | bd_set_size(bdev, size << 9); |
ee862730 | 774 | loop_sysfs_init(lo); |
c3473c63 DZ |
775 | /* let user-space know about the new size */ |
776 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
1da177e4 LT |
777 | |
778 | set_blocksize(bdev, lo_blocksize); | |
779 | ||
6c997918 | 780 | lo->lo_state = Lo_bound; |
e03c8dd1 KS |
781 | if (part_shift) |
782 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
783 | if (lo->lo_flags & LO_FLAGS_PARTSCAN) | |
06f0e9e6 | 784 | loop_reread_partitions(lo, bdev); |
c1681bf8 AP |
785 | |
786 | /* Grab the block_device to prevent its destruction after we | |
787 | * put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev). | |
788 | */ | |
789 | bdgrab(bdev); | |
1da177e4 LT |
790 | return 0; |
791 | ||
792 | out_putf: | |
793 | fput(file); | |
794 | out: | |
795 | /* This is safe: open() is still holding a reference. */ | |
796 | module_put(THIS_MODULE); | |
797 | return error; | |
798 | } | |
799 | ||
800 | static int | |
801 | loop_release_xfer(struct loop_device *lo) | |
802 | { | |
803 | int err = 0; | |
804 | struct loop_func_table *xfer = lo->lo_encryption; | |
805 | ||
806 | if (xfer) { | |
807 | if (xfer->release) | |
808 | err = xfer->release(lo); | |
809 | lo->transfer = NULL; | |
810 | lo->lo_encryption = NULL; | |
811 | module_put(xfer->owner); | |
812 | } | |
813 | return err; | |
814 | } | |
815 | ||
816 | static int | |
817 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, | |
818 | const struct loop_info64 *i) | |
819 | { | |
820 | int err = 0; | |
821 | ||
822 | if (xfer) { | |
823 | struct module *owner = xfer->owner; | |
824 | ||
825 | if (!try_module_get(owner)) | |
826 | return -EINVAL; | |
827 | if (xfer->init) | |
828 | err = xfer->init(lo, i); | |
829 | if (err) | |
830 | module_put(owner); | |
831 | else | |
832 | lo->lo_encryption = xfer; | |
833 | } | |
834 | return err; | |
835 | } | |
836 | ||
4c823cc3 | 837 | static int loop_clr_fd(struct loop_device *lo) |
1da177e4 LT |
838 | { |
839 | struct file *filp = lo->lo_backing_file; | |
b4e3ca1a | 840 | gfp_t gfp = lo->old_gfp_mask; |
4c823cc3 | 841 | struct block_device *bdev = lo->lo_device; |
1da177e4 LT |
842 | |
843 | if (lo->lo_state != Lo_bound) | |
844 | return -ENXIO; | |
845 | ||
a1ecac3b DC |
846 | /* |
847 | * If we've explicitly asked to tear down the loop device, | |
848 | * and it has an elevated reference count, set it for auto-teardown when | |
849 | * the last reference goes away. This stops $!~#$@ udev from | |
850 | * preventing teardown because it decided that it needs to run blkid on | |
851 | * the loopback device whenever they appear. xfstests is notorious for | |
852 | * failing tests because blkid via udev races with a losetup | |
853 | * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d | |
854 | * command to fail with EBUSY. | |
855 | */ | |
f8933667 | 856 | if (atomic_read(&lo->lo_refcnt) > 1) { |
a1ecac3b DC |
857 | lo->lo_flags |= LO_FLAGS_AUTOCLEAR; |
858 | mutex_unlock(&lo->lo_ctl_mutex); | |
859 | return 0; | |
860 | } | |
1da177e4 LT |
861 | |
862 | if (filp == NULL) | |
863 | return -EINVAL; | |
864 | ||
f8933667 ML |
865 | /* freeze request queue during the transition */ |
866 | blk_mq_freeze_queue(lo->lo_queue); | |
867 | ||
1da177e4 LT |
868 | spin_lock_irq(&lo->lo_lock); |
869 | lo->lo_state = Lo_rundown; | |
1da177e4 | 870 | lo->lo_backing_file = NULL; |
05eb0f25 | 871 | spin_unlock_irq(&lo->lo_lock); |
1da177e4 LT |
872 | |
873 | loop_release_xfer(lo); | |
874 | lo->transfer = NULL; | |
875 | lo->ioctl = NULL; | |
876 | lo->lo_device = NULL; | |
877 | lo->lo_encryption = NULL; | |
878 | lo->lo_offset = 0; | |
879 | lo->lo_sizelimit = 0; | |
880 | lo->lo_encrypt_key_size = 0; | |
1da177e4 LT |
881 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
882 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); | |
883 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); | |
c1681bf8 AP |
884 | if (bdev) { |
885 | bdput(bdev); | |
bb214884 | 886 | invalidate_bdev(bdev); |
c1681bf8 | 887 | } |
73285082 | 888 | set_capacity(lo->lo_disk, 0); |
51a0bb0c | 889 | loop_sysfs_exit(lo); |
c3473c63 | 890 | if (bdev) { |
bb214884 | 891 | bd_set_size(bdev, 0); |
c3473c63 DZ |
892 | /* let user-space know about this change */ |
893 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); | |
894 | } | |
1da177e4 LT |
895 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
896 | lo->lo_state = Lo_unbound; | |
1da177e4 LT |
897 | /* This is safe: open() is still holding a reference. */ |
898 | module_put(THIS_MODULE); | |
f8933667 ML |
899 | blk_mq_unfreeze_queue(lo->lo_queue); |
900 | ||
c2fccc1c | 901 | if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) |
06f0e9e6 | 902 | loop_reread_partitions(lo, bdev); |
e03c8dd1 KS |
903 | lo->lo_flags = 0; |
904 | if (!part_shift) | |
905 | lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; | |
f4aa4c7b ML |
906 | destroy_workqueue(lo->wq); |
907 | lo->wq = NULL; | |
f028f3b2 NK |
908 | mutex_unlock(&lo->lo_ctl_mutex); |
909 | /* | |
910 | * Need not hold lo_ctl_mutex to fput backing file. | |
911 | * Calling fput holding lo_ctl_mutex triggers a circular | |
912 | * lock dependency possibility warning as fput can take | |
913 | * bd_mutex which is usually taken before lo_ctl_mutex. | |
914 | */ | |
915 | fput(filp); | |
1da177e4 LT |
916 | return 0; |
917 | } | |
918 | ||
919 | static int | |
920 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) | |
921 | { | |
922 | int err; | |
923 | struct loop_func_table *xfer; | |
e4849737 | 924 | kuid_t uid = current_uid(); |
1da177e4 | 925 | |
b0fafa81 | 926 | if (lo->lo_encrypt_key_size && |
e4849737 | 927 | !uid_eq(lo->lo_key_owner, uid) && |
1da177e4 LT |
928 | !capable(CAP_SYS_ADMIN)) |
929 | return -EPERM; | |
930 | if (lo->lo_state != Lo_bound) | |
931 | return -ENXIO; | |
932 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) | |
933 | return -EINVAL; | |
934 | ||
935 | err = loop_release_xfer(lo); | |
936 | if (err) | |
937 | return err; | |
938 | ||
939 | if (info->lo_encrypt_type) { | |
940 | unsigned int type = info->lo_encrypt_type; | |
941 | ||
942 | if (type >= MAX_LO_CRYPT) | |
943 | return -EINVAL; | |
944 | xfer = xfer_funcs[type]; | |
945 | if (xfer == NULL) | |
946 | return -EINVAL; | |
947 | } else | |
948 | xfer = NULL; | |
949 | ||
950 | err = loop_init_xfer(lo, xfer, info); | |
951 | if (err) | |
952 | return err; | |
953 | ||
954 | if (lo->lo_offset != info->lo_offset || | |
7b0576a3 | 955 | lo->lo_sizelimit != info->lo_sizelimit) |
7035b5df | 956 | if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) |
1da177e4 | 957 | return -EFBIG; |
541c742a | 958 | |
dfaa2ef6 | 959 | loop_config_discard(lo); |
1da177e4 LT |
960 | |
961 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); | |
962 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); | |
963 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; | |
964 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; | |
965 | ||
966 | if (!xfer) | |
967 | xfer = &none_funcs; | |
968 | lo->transfer = xfer->transfer; | |
969 | lo->ioctl = xfer->ioctl; | |
970 | ||
96c58655 DW |
971 | if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != |
972 | (info->lo_flags & LO_FLAGS_AUTOCLEAR)) | |
973 | lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; | |
974 | ||
e03c8dd1 KS |
975 | if ((info->lo_flags & LO_FLAGS_PARTSCAN) && |
976 | !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { | |
977 | lo->lo_flags |= LO_FLAGS_PARTSCAN; | |
978 | lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; | |
06f0e9e6 | 979 | loop_reread_partitions(lo, lo->lo_device); |
e03c8dd1 KS |
980 | } |
981 | ||
1da177e4 LT |
982 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; |
983 | lo->lo_init[0] = info->lo_init[0]; | |
984 | lo->lo_init[1] = info->lo_init[1]; | |
985 | if (info->lo_encrypt_key_size) { | |
986 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, | |
987 | info->lo_encrypt_key_size); | |
b0fafa81 | 988 | lo->lo_key_owner = uid; |
aa4d8616 | 989 | } |
1da177e4 LT |
990 | |
991 | return 0; | |
992 | } | |
993 | ||
994 | static int | |
995 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) | |
996 | { | |
997 | struct file *file = lo->lo_backing_file; | |
998 | struct kstat stat; | |
999 | int error; | |
1000 | ||
1001 | if (lo->lo_state != Lo_bound) | |
1002 | return -ENXIO; | |
3dadecce | 1003 | error = vfs_getattr(&file->f_path, &stat); |
1da177e4 LT |
1004 | if (error) |
1005 | return error; | |
1006 | memset(info, 0, sizeof(*info)); | |
1007 | info->lo_number = lo->lo_number; | |
1008 | info->lo_device = huge_encode_dev(stat.dev); | |
1009 | info->lo_inode = stat.ino; | |
1010 | info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev); | |
1011 | info->lo_offset = lo->lo_offset; | |
1012 | info->lo_sizelimit = lo->lo_sizelimit; | |
1013 | info->lo_flags = lo->lo_flags; | |
1014 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); | |
1015 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); | |
1016 | info->lo_encrypt_type = | |
1017 | lo->lo_encryption ? lo->lo_encryption->number : 0; | |
1018 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { | |
1019 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; | |
1020 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, | |
1021 | lo->lo_encrypt_key_size); | |
1022 | } | |
1023 | return 0; | |
1024 | } | |
1025 | ||
1026 | static void | |
1027 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) | |
1028 | { | |
1029 | memset(info64, 0, sizeof(*info64)); | |
1030 | info64->lo_number = info->lo_number; | |
1031 | info64->lo_device = info->lo_device; | |
1032 | info64->lo_inode = info->lo_inode; | |
1033 | info64->lo_rdevice = info->lo_rdevice; | |
1034 | info64->lo_offset = info->lo_offset; | |
1035 | info64->lo_sizelimit = 0; | |
1036 | info64->lo_encrypt_type = info->lo_encrypt_type; | |
1037 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; | |
1038 | info64->lo_flags = info->lo_flags; | |
1039 | info64->lo_init[0] = info->lo_init[0]; | |
1040 | info64->lo_init[1] = info->lo_init[1]; | |
1041 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1042 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); | |
1043 | else | |
1044 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); | |
1045 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); | |
1046 | } | |
1047 | ||
1048 | static int | |
1049 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) | |
1050 | { | |
1051 | memset(info, 0, sizeof(*info)); | |
1052 | info->lo_number = info64->lo_number; | |
1053 | info->lo_device = info64->lo_device; | |
1054 | info->lo_inode = info64->lo_inode; | |
1055 | info->lo_rdevice = info64->lo_rdevice; | |
1056 | info->lo_offset = info64->lo_offset; | |
1057 | info->lo_encrypt_type = info64->lo_encrypt_type; | |
1058 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1059 | info->lo_flags = info64->lo_flags; | |
1060 | info->lo_init[0] = info64->lo_init[0]; | |
1061 | info->lo_init[1] = info64->lo_init[1]; | |
1062 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1063 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1064 | else | |
1065 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1066 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1067 | ||
1068 | /* error in case values were truncated */ | |
1069 | if (info->lo_device != info64->lo_device || | |
1070 | info->lo_rdevice != info64->lo_rdevice || | |
1071 | info->lo_inode != info64->lo_inode || | |
1072 | info->lo_offset != info64->lo_offset) | |
1073 | return -EOVERFLOW; | |
1074 | ||
1075 | return 0; | |
1076 | } | |
1077 | ||
1078 | static int | |
1079 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) | |
1080 | { | |
1081 | struct loop_info info; | |
1082 | struct loop_info64 info64; | |
1083 | ||
1084 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) | |
1085 | return -EFAULT; | |
1086 | loop_info64_from_old(&info, &info64); | |
1087 | return loop_set_status(lo, &info64); | |
1088 | } | |
1089 | ||
1090 | static int | |
1091 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) | |
1092 | { | |
1093 | struct loop_info64 info64; | |
1094 | ||
1095 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) | |
1096 | return -EFAULT; | |
1097 | return loop_set_status(lo, &info64); | |
1098 | } | |
1099 | ||
1100 | static int | |
1101 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { | |
1102 | struct loop_info info; | |
1103 | struct loop_info64 info64; | |
1104 | int err = 0; | |
1105 | ||
1106 | if (!arg) | |
1107 | err = -EINVAL; | |
1108 | if (!err) | |
1109 | err = loop_get_status(lo, &info64); | |
1110 | if (!err) | |
1111 | err = loop_info64_to_old(&info64, &info); | |
1112 | if (!err && copy_to_user(arg, &info, sizeof(info))) | |
1113 | err = -EFAULT; | |
1114 | ||
1115 | return err; | |
1116 | } | |
1117 | ||
1118 | static int | |
1119 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { | |
1120 | struct loop_info64 info64; | |
1121 | int err = 0; | |
1122 | ||
1123 | if (!arg) | |
1124 | err = -EINVAL; | |
1125 | if (!err) | |
1126 | err = loop_get_status(lo, &info64); | |
1127 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) | |
1128 | err = -EFAULT; | |
1129 | ||
1130 | return err; | |
1131 | } | |
1132 | ||
53d66608 O |
1133 | static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) |
1134 | { | |
53d66608 | 1135 | if (unlikely(lo->lo_state != Lo_bound)) |
7b0576a3 | 1136 | return -ENXIO; |
53d66608 | 1137 | |
7b0576a3 | 1138 | return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); |
53d66608 O |
1139 | } |
1140 | ||
bb214884 | 1141 | static int lo_ioctl(struct block_device *bdev, fmode_t mode, |
1da177e4 LT |
1142 | unsigned int cmd, unsigned long arg) |
1143 | { | |
bb214884 | 1144 | struct loop_device *lo = bdev->bd_disk->private_data; |
1da177e4 LT |
1145 | int err; |
1146 | ||
f028f3b2 | 1147 | mutex_lock_nested(&lo->lo_ctl_mutex, 1); |
1da177e4 LT |
1148 | switch (cmd) { |
1149 | case LOOP_SET_FD: | |
bb214884 | 1150 | err = loop_set_fd(lo, mode, bdev, arg); |
1da177e4 LT |
1151 | break; |
1152 | case LOOP_CHANGE_FD: | |
bb214884 | 1153 | err = loop_change_fd(lo, bdev, arg); |
1da177e4 LT |
1154 | break; |
1155 | case LOOP_CLR_FD: | |
f028f3b2 | 1156 | /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ |
4c823cc3 | 1157 | err = loop_clr_fd(lo); |
f028f3b2 NK |
1158 | if (!err) |
1159 | goto out_unlocked; | |
1da177e4 LT |
1160 | break; |
1161 | case LOOP_SET_STATUS: | |
7035b5df DM |
1162 | err = -EPERM; |
1163 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1164 | err = loop_set_status_old(lo, | |
1165 | (struct loop_info __user *)arg); | |
1da177e4 LT |
1166 | break; |
1167 | case LOOP_GET_STATUS: | |
1168 | err = loop_get_status_old(lo, (struct loop_info __user *) arg); | |
1169 | break; | |
1170 | case LOOP_SET_STATUS64: | |
7035b5df DM |
1171 | err = -EPERM; |
1172 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1173 | err = loop_set_status64(lo, | |
1174 | (struct loop_info64 __user *) arg); | |
1da177e4 LT |
1175 | break; |
1176 | case LOOP_GET_STATUS64: | |
1177 | err = loop_get_status64(lo, (struct loop_info64 __user *) arg); | |
1178 | break; | |
53d66608 O |
1179 | case LOOP_SET_CAPACITY: |
1180 | err = -EPERM; | |
1181 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) | |
1182 | err = loop_set_capacity(lo, bdev); | |
1183 | break; | |
1da177e4 LT |
1184 | default: |
1185 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; | |
1186 | } | |
f85221dd | 1187 | mutex_unlock(&lo->lo_ctl_mutex); |
f028f3b2 NK |
1188 | |
1189 | out_unlocked: | |
1da177e4 LT |
1190 | return err; |
1191 | } | |
1192 | ||
863d5b82 DH |
1193 | #ifdef CONFIG_COMPAT |
1194 | struct compat_loop_info { | |
1195 | compat_int_t lo_number; /* ioctl r/o */ | |
1196 | compat_dev_t lo_device; /* ioctl r/o */ | |
1197 | compat_ulong_t lo_inode; /* ioctl r/o */ | |
1198 | compat_dev_t lo_rdevice; /* ioctl r/o */ | |
1199 | compat_int_t lo_offset; | |
1200 | compat_int_t lo_encrypt_type; | |
1201 | compat_int_t lo_encrypt_key_size; /* ioctl w/o */ | |
1202 | compat_int_t lo_flags; /* ioctl r/o */ | |
1203 | char lo_name[LO_NAME_SIZE]; | |
1204 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ | |
1205 | compat_ulong_t lo_init[2]; | |
1206 | char reserved[4]; | |
1207 | }; | |
1208 | ||
1209 | /* | |
1210 | * Transfer 32-bit compatibility structure in userspace to 64-bit loop info | |
1211 | * - noinlined to reduce stack space usage in main part of driver | |
1212 | */ | |
1213 | static noinline int | |
ba674cfc | 1214 | loop_info64_from_compat(const struct compat_loop_info __user *arg, |
863d5b82 DH |
1215 | struct loop_info64 *info64) |
1216 | { | |
1217 | struct compat_loop_info info; | |
1218 | ||
1219 | if (copy_from_user(&info, arg, sizeof(info))) | |
1220 | return -EFAULT; | |
1221 | ||
1222 | memset(info64, 0, sizeof(*info64)); | |
1223 | info64->lo_number = info.lo_number; | |
1224 | info64->lo_device = info.lo_device; | |
1225 | info64->lo_inode = info.lo_inode; | |
1226 | info64->lo_rdevice = info.lo_rdevice; | |
1227 | info64->lo_offset = info.lo_offset; | |
1228 | info64->lo_sizelimit = 0; | |
1229 | info64->lo_encrypt_type = info.lo_encrypt_type; | |
1230 | info64->lo_encrypt_key_size = info.lo_encrypt_key_size; | |
1231 | info64->lo_flags = info.lo_flags; | |
1232 | info64->lo_init[0] = info.lo_init[0]; | |
1233 | info64->lo_init[1] = info.lo_init[1]; | |
1234 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1235 | memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); | |
1236 | else | |
1237 | memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); | |
1238 | memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); | |
1239 | return 0; | |
1240 | } | |
1241 | ||
1242 | /* | |
1243 | * Transfer 64-bit loop info to 32-bit compatibility structure in userspace | |
1244 | * - noinlined to reduce stack space usage in main part of driver | |
1245 | */ | |
1246 | static noinline int | |
1247 | loop_info64_to_compat(const struct loop_info64 *info64, | |
1248 | struct compat_loop_info __user *arg) | |
1249 | { | |
1250 | struct compat_loop_info info; | |
1251 | ||
1252 | memset(&info, 0, sizeof(info)); | |
1253 | info.lo_number = info64->lo_number; | |
1254 | info.lo_device = info64->lo_device; | |
1255 | info.lo_inode = info64->lo_inode; | |
1256 | info.lo_rdevice = info64->lo_rdevice; | |
1257 | info.lo_offset = info64->lo_offset; | |
1258 | info.lo_encrypt_type = info64->lo_encrypt_type; | |
1259 | info.lo_encrypt_key_size = info64->lo_encrypt_key_size; | |
1260 | info.lo_flags = info64->lo_flags; | |
1261 | info.lo_init[0] = info64->lo_init[0]; | |
1262 | info.lo_init[1] = info64->lo_init[1]; | |
1263 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) | |
1264 | memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); | |
1265 | else | |
1266 | memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); | |
1267 | memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); | |
1268 | ||
1269 | /* error in case values were truncated */ | |
1270 | if (info.lo_device != info64->lo_device || | |
1271 | info.lo_rdevice != info64->lo_rdevice || | |
1272 | info.lo_inode != info64->lo_inode || | |
1273 | info.lo_offset != info64->lo_offset || | |
1274 | info.lo_init[0] != info64->lo_init[0] || | |
1275 | info.lo_init[1] != info64->lo_init[1]) | |
1276 | return -EOVERFLOW; | |
1277 | ||
1278 | if (copy_to_user(arg, &info, sizeof(info))) | |
1279 | return -EFAULT; | |
1280 | return 0; | |
1281 | } | |
1282 | ||
1283 | static int | |
1284 | loop_set_status_compat(struct loop_device *lo, | |
1285 | const struct compat_loop_info __user *arg) | |
1286 | { | |
1287 | struct loop_info64 info64; | |
1288 | int ret; | |
1289 | ||
1290 | ret = loop_info64_from_compat(arg, &info64); | |
1291 | if (ret < 0) | |
1292 | return ret; | |
1293 | return loop_set_status(lo, &info64); | |
1294 | } | |
1295 | ||
1296 | static int | |
1297 | loop_get_status_compat(struct loop_device *lo, | |
1298 | struct compat_loop_info __user *arg) | |
1299 | { | |
1300 | struct loop_info64 info64; | |
1301 | int err = 0; | |
1302 | ||
1303 | if (!arg) | |
1304 | err = -EINVAL; | |
1305 | if (!err) | |
1306 | err = loop_get_status(lo, &info64); | |
1307 | if (!err) | |
1308 | err = loop_info64_to_compat(&info64, arg); | |
1309 | return err; | |
1310 | } | |
1311 | ||
bb214884 AV |
1312 | static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
1313 | unsigned int cmd, unsigned long arg) | |
863d5b82 | 1314 | { |
bb214884 | 1315 | struct loop_device *lo = bdev->bd_disk->private_data; |
863d5b82 DH |
1316 | int err; |
1317 | ||
863d5b82 DH |
1318 | switch(cmd) { |
1319 | case LOOP_SET_STATUS: | |
1320 | mutex_lock(&lo->lo_ctl_mutex); | |
1321 | err = loop_set_status_compat( | |
1322 | lo, (const struct compat_loop_info __user *) arg); | |
1323 | mutex_unlock(&lo->lo_ctl_mutex); | |
1324 | break; | |
1325 | case LOOP_GET_STATUS: | |
1326 | mutex_lock(&lo->lo_ctl_mutex); | |
1327 | err = loop_get_status_compat( | |
1328 | lo, (struct compat_loop_info __user *) arg); | |
1329 | mutex_unlock(&lo->lo_ctl_mutex); | |
1330 | break; | |
53d66608 | 1331 | case LOOP_SET_CAPACITY: |
863d5b82 DH |
1332 | case LOOP_CLR_FD: |
1333 | case LOOP_GET_STATUS64: | |
1334 | case LOOP_SET_STATUS64: | |
1335 | arg = (unsigned long) compat_ptr(arg); | |
1336 | case LOOP_SET_FD: | |
1337 | case LOOP_CHANGE_FD: | |
bb214884 | 1338 | err = lo_ioctl(bdev, mode, cmd, arg); |
863d5b82 DH |
1339 | break; |
1340 | default: | |
1341 | err = -ENOIOCTLCMD; | |
1342 | break; | |
1343 | } | |
863d5b82 DH |
1344 | return err; |
1345 | } | |
1346 | #endif | |
1347 | ||
bb214884 | 1348 | static int lo_open(struct block_device *bdev, fmode_t mode) |
1da177e4 | 1349 | { |
770fe30a KS |
1350 | struct loop_device *lo; |
1351 | int err = 0; | |
1352 | ||
1353 | mutex_lock(&loop_index_mutex); | |
1354 | lo = bdev->bd_disk->private_data; | |
1355 | if (!lo) { | |
1356 | err = -ENXIO; | |
1357 | goto out; | |
1358 | } | |
1da177e4 | 1359 | |
f8933667 | 1360 | atomic_inc(&lo->lo_refcnt); |
770fe30a KS |
1361 | out: |
1362 | mutex_unlock(&loop_index_mutex); | |
1363 | return err; | |
1da177e4 LT |
1364 | } |
1365 | ||
db2a144b | 1366 | static void lo_release(struct gendisk *disk, fmode_t mode) |
1da177e4 | 1367 | { |
bb214884 | 1368 | struct loop_device *lo = disk->private_data; |
ffcd7dca | 1369 | int err; |
1da177e4 | 1370 | |
f8933667 ML |
1371 | if (atomic_dec_return(&lo->lo_refcnt)) |
1372 | return; | |
14f27939 | 1373 | |
f8933667 | 1374 | mutex_lock(&lo->lo_ctl_mutex); |
14f27939 MB |
1375 | if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { |
1376 | /* | |
1377 | * In autoclear mode, stop the loop thread | |
1378 | * and remove configuration after last close. | |
1379 | */ | |
4c823cc3 | 1380 | err = loop_clr_fd(lo); |
ffcd7dca | 1381 | if (!err) |
db2a144b | 1382 | return; |
14f27939 MB |
1383 | } else { |
1384 | /* | |
1385 | * Otherwise keep thread (if running) and config, | |
1386 | * but flush possible ongoing bios in thread. | |
1387 | */ | |
1388 | loop_flush(lo); | |
1389 | } | |
96c58655 | 1390 | |
f85221dd | 1391 | mutex_unlock(&lo->lo_ctl_mutex); |
1da177e4 LT |
1392 | } |
1393 | ||
83d5cde4 | 1394 | static const struct block_device_operations lo_fops = { |
1da177e4 | 1395 | .owner = THIS_MODULE, |
bb214884 AV |
1396 | .open = lo_open, |
1397 | .release = lo_release, | |
1398 | .ioctl = lo_ioctl, | |
863d5b82 | 1399 | #ifdef CONFIG_COMPAT |
bb214884 | 1400 | .compat_ioctl = lo_compat_ioctl, |
863d5b82 | 1401 | #endif |
1da177e4 LT |
1402 | }; |
1403 | ||
1404 | /* | |
1405 | * And now the modules code and kernel interface. | |
1406 | */ | |
73285082 | 1407 | static int max_loop; |
ac04fee0 | 1408 | module_param(max_loop, int, S_IRUGO); |
a47653fc | 1409 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
ac04fee0 | 1410 | module_param(max_part, int, S_IRUGO); |
476a4813 | 1411 | MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
1da177e4 LT |
1412 | MODULE_LICENSE("GPL"); |
1413 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); | |
1414 | ||
1415 | int loop_register_transfer(struct loop_func_table *funcs) | |
1416 | { | |
1417 | unsigned int n = funcs->number; | |
1418 | ||
1419 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) | |
1420 | return -EINVAL; | |
1421 | xfer_funcs[n] = funcs; | |
1422 | return 0; | |
1423 | } | |
1424 | ||
34dd82af KS |
1425 | static int unregister_transfer_cb(int id, void *ptr, void *data) |
1426 | { | |
1427 | struct loop_device *lo = ptr; | |
1428 | struct loop_func_table *xfer = data; | |
1429 | ||
1430 | mutex_lock(&lo->lo_ctl_mutex); | |
1431 | if (lo->lo_encryption == xfer) | |
1432 | loop_release_xfer(lo); | |
1433 | mutex_unlock(&lo->lo_ctl_mutex); | |
1434 | return 0; | |
1435 | } | |
1436 | ||
1da177e4 LT |
1437 | int loop_unregister_transfer(int number) |
1438 | { | |
1439 | unsigned int n = number; | |
1da177e4 LT |
1440 | struct loop_func_table *xfer; |
1441 | ||
1442 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) | |
1443 | return -EINVAL; | |
1444 | ||
1445 | xfer_funcs[n] = NULL; | |
34dd82af | 1446 | idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer); |
1da177e4 LT |
1447 | return 0; |
1448 | } | |
1449 | ||
1450 | EXPORT_SYMBOL(loop_register_transfer); | |
1451 | EXPORT_SYMBOL(loop_unregister_transfer); | |
1452 | ||
b5dd2f60 ML |
1453 | static int loop_queue_rq(struct blk_mq_hw_ctx *hctx, |
1454 | const struct blk_mq_queue_data *bd) | |
1455 | { | |
1456 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); | |
f4aa4c7b | 1457 | struct loop_device *lo = cmd->rq->q->queuedata; |
b5dd2f60 ML |
1458 | |
1459 | blk_mq_start_request(bd->rq); | |
1460 | ||
f4aa4c7b ML |
1461 | if (lo->lo_state != Lo_bound) |
1462 | return -EIO; | |
1463 | ||
b5dd2f60 ML |
1464 | if (cmd->rq->cmd_flags & REQ_WRITE) { |
1465 | struct loop_device *lo = cmd->rq->q->queuedata; | |
1466 | bool need_sched = true; | |
1467 | ||
1468 | spin_lock_irq(&lo->lo_lock); | |
1469 | if (lo->write_started) | |
1470 | need_sched = false; | |
1471 | else | |
1472 | lo->write_started = true; | |
1473 | list_add_tail(&cmd->list, &lo->write_cmd_head); | |
1474 | spin_unlock_irq(&lo->lo_lock); | |
1475 | ||
1476 | if (need_sched) | |
f4aa4c7b | 1477 | queue_work(lo->wq, &lo->write_work); |
b5dd2f60 | 1478 | } else { |
f4aa4c7b | 1479 | queue_work(lo->wq, &cmd->read_work); |
b5dd2f60 ML |
1480 | } |
1481 | ||
1482 | return BLK_MQ_RQ_QUEUE_OK; | |
1483 | } | |
1484 | ||
1485 | static void loop_handle_cmd(struct loop_cmd *cmd) | |
1486 | { | |
1487 | const bool write = cmd->rq->cmd_flags & REQ_WRITE; | |
1488 | struct loop_device *lo = cmd->rq->q->queuedata; | |
1489 | int ret = -EIO; | |
b5dd2f60 | 1490 | |
b5dd2f60 ML |
1491 | if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) |
1492 | goto failed; | |
1493 | ||
30112013 | 1494 | ret = do_req_filebacked(lo, cmd->rq); |
b5dd2f60 ML |
1495 | |
1496 | failed: | |
1497 | if (ret) | |
1498 | cmd->rq->errors = -EIO; | |
1499 | blk_mq_complete_request(cmd->rq); | |
1500 | } | |
1501 | ||
1502 | static void loop_queue_write_work(struct work_struct *work) | |
1503 | { | |
1504 | struct loop_device *lo = | |
1505 | container_of(work, struct loop_device, write_work); | |
1506 | LIST_HEAD(cmd_list); | |
1507 | ||
1508 | spin_lock_irq(&lo->lo_lock); | |
1509 | repeat: | |
1510 | list_splice_init(&lo->write_cmd_head, &cmd_list); | |
1511 | spin_unlock_irq(&lo->lo_lock); | |
1512 | ||
1513 | while (!list_empty(&cmd_list)) { | |
1514 | struct loop_cmd *cmd = list_first_entry(&cmd_list, | |
1515 | struct loop_cmd, list); | |
1516 | list_del_init(&cmd->list); | |
1517 | loop_handle_cmd(cmd); | |
1518 | } | |
1519 | ||
1520 | spin_lock_irq(&lo->lo_lock); | |
1521 | if (!list_empty(&lo->write_cmd_head)) | |
1522 | goto repeat; | |
1523 | lo->write_started = false; | |
1524 | spin_unlock_irq(&lo->lo_lock); | |
1525 | } | |
1526 | ||
1527 | static void loop_queue_read_work(struct work_struct *work) | |
1528 | { | |
1529 | struct loop_cmd *cmd = | |
1530 | container_of(work, struct loop_cmd, read_work); | |
1531 | ||
1532 | loop_handle_cmd(cmd); | |
1533 | } | |
1534 | ||
1535 | static int loop_init_request(void *data, struct request *rq, | |
1536 | unsigned int hctx_idx, unsigned int request_idx, | |
1537 | unsigned int numa_node) | |
1538 | { | |
1539 | struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); | |
1540 | ||
1541 | cmd->rq = rq; | |
1542 | INIT_WORK(&cmd->read_work, loop_queue_read_work); | |
1543 | ||
1544 | return 0; | |
1545 | } | |
1546 | ||
1547 | static struct blk_mq_ops loop_mq_ops = { | |
1548 | .queue_rq = loop_queue_rq, | |
1549 | .map_queue = blk_mq_map_queue, | |
1550 | .init_request = loop_init_request, | |
1551 | }; | |
1552 | ||
34dd82af | 1553 | static int loop_add(struct loop_device **l, int i) |
73285082 KC |
1554 | { |
1555 | struct loop_device *lo; | |
1556 | struct gendisk *disk; | |
34dd82af | 1557 | int err; |
73285082 | 1558 | |
68d740d7 | 1559 | err = -ENOMEM; |
73285082 | 1560 | lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
68d740d7 | 1561 | if (!lo) |
73285082 | 1562 | goto out; |
34dd82af | 1563 | |
ef7e7c82 MP |
1564 | lo->lo_state = Lo_unbound; |
1565 | ||
c718aa65 | 1566 | /* allocate id, if @id >= 0, we're requesting that specific id */ |
34dd82af | 1567 | if (i >= 0) { |
c718aa65 TH |
1568 | err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL); |
1569 | if (err == -ENOSPC) | |
34dd82af | 1570 | err = -EEXIST; |
34dd82af | 1571 | } else { |
c718aa65 | 1572 | err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL); |
34dd82af KS |
1573 | } |
1574 | if (err < 0) | |
1575 | goto out_free_dev; | |
c718aa65 | 1576 | i = err; |
73285082 | 1577 | |
183cfb57 | 1578 | err = -ENOMEM; |
b5dd2f60 ML |
1579 | lo->tag_set.ops = &loop_mq_ops; |
1580 | lo->tag_set.nr_hw_queues = 1; | |
1581 | lo->tag_set.queue_depth = 128; | |
1582 | lo->tag_set.numa_node = NUMA_NO_NODE; | |
1583 | lo->tag_set.cmd_size = sizeof(struct loop_cmd); | |
1584 | lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; | |
1585 | lo->tag_set.driver_data = lo; | |
1586 | ||
1587 | err = blk_mq_alloc_tag_set(&lo->tag_set); | |
1588 | if (err) | |
3ec981e3 | 1589 | goto out_free_idr; |
73285082 | 1590 | |
b5dd2f60 ML |
1591 | lo->lo_queue = blk_mq_init_queue(&lo->tag_set); |
1592 | if (IS_ERR_OR_NULL(lo->lo_queue)) { | |
1593 | err = PTR_ERR(lo->lo_queue); | |
1594 | goto out_cleanup_tags; | |
1595 | } | |
ef7e7c82 MP |
1596 | lo->lo_queue->queuedata = lo; |
1597 | ||
b5dd2f60 ML |
1598 | INIT_LIST_HEAD(&lo->write_cmd_head); |
1599 | INIT_WORK(&lo->write_work, loop_queue_write_work); | |
1600 | ||
476a4813 | 1601 | disk = lo->lo_disk = alloc_disk(1 << part_shift); |
73285082 KC |
1602 | if (!disk) |
1603 | goto out_free_queue; | |
1604 | ||
e03c8dd1 KS |
1605 | /* |
1606 | * Disable partition scanning by default. The in-kernel partition | |
1607 | * scanning can be requested individually per-device during its | |
1608 | * setup. Userspace can always add and remove partitions from all | |
1609 | * devices. The needed partition minors are allocated from the | |
1610 | * extended minor space, the main loop device numbers will continue | |
1611 | * to match the loop minors, regardless of the number of partitions | |
1612 | * used. | |
1613 | * | |
1614 | * If max_part is given, partition scanning is globally enabled for | |
1615 | * all loop devices. The minors for the main loop devices will be | |
1616 | * multiples of max_part. | |
1617 | * | |
1618 | * Note: Global-for-all-devices, set-only-at-init, read-only module | |
1619 | * parameteters like 'max_loop' and 'max_part' make things needlessly | |
1620 | * complicated, are too static, inflexible and may surprise | |
1621 | * userspace tools. Parameters like this in general should be avoided. | |
1622 | */ | |
1623 | if (!part_shift) | |
1624 | disk->flags |= GENHD_FL_NO_PART_SCAN; | |
1625 | disk->flags |= GENHD_FL_EXT_DEVT; | |
73285082 | 1626 | mutex_init(&lo->lo_ctl_mutex); |
f8933667 | 1627 | atomic_set(&lo->lo_refcnt, 0); |
73285082 | 1628 | lo->lo_number = i; |
73285082 KC |
1629 | spin_lock_init(&lo->lo_lock); |
1630 | disk->major = LOOP_MAJOR; | |
476a4813 | 1631 | disk->first_minor = i << part_shift; |
73285082 KC |
1632 | disk->fops = &lo_fops; |
1633 | disk->private_data = lo; | |
1634 | disk->queue = lo->lo_queue; | |
1635 | sprintf(disk->disk_name, "loop%d", i); | |
34dd82af KS |
1636 | add_disk(disk); |
1637 | *l = lo; | |
1638 | return lo->lo_number; | |
73285082 KC |
1639 | |
1640 | out_free_queue: | |
1641 | blk_cleanup_queue(lo->lo_queue); | |
b5dd2f60 ML |
1642 | out_cleanup_tags: |
1643 | blk_mq_free_tag_set(&lo->tag_set); | |
3ec981e3 MP |
1644 | out_free_idr: |
1645 | idr_remove(&loop_index_idr, i); | |
73285082 KC |
1646 | out_free_dev: |
1647 | kfree(lo); | |
1648 | out: | |
34dd82af | 1649 | return err; |
73285082 KC |
1650 | } |
1651 | ||
34dd82af | 1652 | static void loop_remove(struct loop_device *lo) |
1da177e4 | 1653 | { |
73285082 | 1654 | blk_cleanup_queue(lo->lo_queue); |
6cd18e71 | 1655 | del_gendisk(lo->lo_disk); |
b5dd2f60 | 1656 | blk_mq_free_tag_set(&lo->tag_set); |
73285082 | 1657 | put_disk(lo->lo_disk); |
73285082 KC |
1658 | kfree(lo); |
1659 | } | |
1da177e4 | 1660 | |
770fe30a KS |
1661 | static int find_free_cb(int id, void *ptr, void *data) |
1662 | { | |
1663 | struct loop_device *lo = ptr; | |
1664 | struct loop_device **l = data; | |
1665 | ||
1666 | if (lo->lo_state == Lo_unbound) { | |
1667 | *l = lo; | |
1668 | return 1; | |
1669 | } | |
1670 | return 0; | |
1671 | } | |
1672 | ||
34dd82af | 1673 | static int loop_lookup(struct loop_device **l, int i) |
a47653fc KC |
1674 | { |
1675 | struct loop_device *lo; | |
34dd82af | 1676 | int ret = -ENODEV; |
a47653fc | 1677 | |
770fe30a KS |
1678 | if (i < 0) { |
1679 | int err; | |
1680 | ||
1681 | err = idr_for_each(&loop_index_idr, &find_free_cb, &lo); | |
1682 | if (err == 1) { | |
1683 | *l = lo; | |
1684 | ret = lo->lo_number; | |
1685 | } | |
1686 | goto out; | |
a47653fc KC |
1687 | } |
1688 | ||
770fe30a | 1689 | /* lookup and return a specific i */ |
34dd82af | 1690 | lo = idr_find(&loop_index_idr, i); |
a47653fc | 1691 | if (lo) { |
34dd82af KS |
1692 | *l = lo; |
1693 | ret = lo->lo_number; | |
a47653fc | 1694 | } |
770fe30a | 1695 | out: |
34dd82af | 1696 | return ret; |
a47653fc KC |
1697 | } |
1698 | ||
73285082 KC |
1699 | static struct kobject *loop_probe(dev_t dev, int *part, void *data) |
1700 | { | |
705962cc | 1701 | struct loop_device *lo; |
07002e99 | 1702 | struct kobject *kobj; |
34dd82af | 1703 | int err; |
73285082 | 1704 | |
34dd82af KS |
1705 | mutex_lock(&loop_index_mutex); |
1706 | err = loop_lookup(&lo, MINOR(dev) >> part_shift); | |
1707 | if (err < 0) | |
1708 | err = loop_add(&lo, MINOR(dev) >> part_shift); | |
1709 | if (err < 0) | |
a207f593 | 1710 | kobj = NULL; |
34dd82af KS |
1711 | else |
1712 | kobj = get_disk(lo->lo_disk); | |
1713 | mutex_unlock(&loop_index_mutex); | |
73285082 KC |
1714 | |
1715 | *part = 0; | |
07002e99 | 1716 | return kobj; |
73285082 KC |
1717 | } |
1718 | ||
770fe30a KS |
1719 | static long loop_control_ioctl(struct file *file, unsigned int cmd, |
1720 | unsigned long parm) | |
1721 | { | |
1722 | struct loop_device *lo; | |
1723 | int ret = -ENOSYS; | |
1724 | ||
1725 | mutex_lock(&loop_index_mutex); | |
1726 | switch (cmd) { | |
1727 | case LOOP_CTL_ADD: | |
1728 | ret = loop_lookup(&lo, parm); | |
1729 | if (ret >= 0) { | |
1730 | ret = -EEXIST; | |
1731 | break; | |
1732 | } | |
1733 | ret = loop_add(&lo, parm); | |
1734 | break; | |
1735 | case LOOP_CTL_REMOVE: | |
1736 | ret = loop_lookup(&lo, parm); | |
1737 | if (ret < 0) | |
1738 | break; | |
1739 | mutex_lock(&lo->lo_ctl_mutex); | |
1740 | if (lo->lo_state != Lo_unbound) { | |
1741 | ret = -EBUSY; | |
1742 | mutex_unlock(&lo->lo_ctl_mutex); | |
1743 | break; | |
1744 | } | |
f8933667 | 1745 | if (atomic_read(&lo->lo_refcnt) > 0) { |
770fe30a KS |
1746 | ret = -EBUSY; |
1747 | mutex_unlock(&lo->lo_ctl_mutex); | |
1748 | break; | |
1749 | } | |
1750 | lo->lo_disk->private_data = NULL; | |
1751 | mutex_unlock(&lo->lo_ctl_mutex); | |
1752 | idr_remove(&loop_index_idr, lo->lo_number); | |
1753 | loop_remove(lo); | |
1754 | break; | |
1755 | case LOOP_CTL_GET_FREE: | |
1756 | ret = loop_lookup(&lo, -1); | |
1757 | if (ret >= 0) | |
1758 | break; | |
1759 | ret = loop_add(&lo, -1); | |
1760 | } | |
1761 | mutex_unlock(&loop_index_mutex); | |
1762 | ||
1763 | return ret; | |
1764 | } | |
1765 | ||
1766 | static const struct file_operations loop_ctl_fops = { | |
1767 | .open = nonseekable_open, | |
1768 | .unlocked_ioctl = loop_control_ioctl, | |
1769 | .compat_ioctl = loop_control_ioctl, | |
1770 | .owner = THIS_MODULE, | |
1771 | .llseek = noop_llseek, | |
1772 | }; | |
1773 | ||
1774 | static struct miscdevice loop_misc = { | |
1775 | .minor = LOOP_CTRL_MINOR, | |
1776 | .name = "loop-control", | |
1777 | .fops = &loop_ctl_fops, | |
1778 | }; | |
1779 | ||
1780 | MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR); | |
1781 | MODULE_ALIAS("devname:loop-control"); | |
1782 | ||
73285082 KC |
1783 | static int __init loop_init(void) |
1784 | { | |
a47653fc KC |
1785 | int i, nr; |
1786 | unsigned long range; | |
34dd82af | 1787 | struct loop_device *lo; |
770fe30a | 1788 | int err; |
a47653fc | 1789 | |
770fe30a KS |
1790 | err = misc_register(&loop_misc); |
1791 | if (err < 0) | |
1792 | return err; | |
476a4813 LV |
1793 | |
1794 | part_shift = 0; | |
ac04fee0 | 1795 | if (max_part > 0) { |
476a4813 LV |
1796 | part_shift = fls(max_part); |
1797 | ||
ac04fee0 NK |
1798 | /* |
1799 | * Adjust max_part according to part_shift as it is exported | |
1800 | * to user space so that user can decide correct minor number | |
1801 | * if [s]he want to create more devices. | |
1802 | * | |
1803 | * Note that -1 is required because partition 0 is reserved | |
1804 | * for the whole disk. | |
1805 | */ | |
1806 | max_part = (1UL << part_shift) - 1; | |
1807 | } | |
1808 | ||
b1a66504 GC |
1809 | if ((1UL << part_shift) > DISK_MAX_PARTS) { |
1810 | err = -EINVAL; | |
1811 | goto misc_out; | |
1812 | } | |
78f4bb36 | 1813 | |
b1a66504 GC |
1814 | if (max_loop > 1UL << (MINORBITS - part_shift)) { |
1815 | err = -EINVAL; | |
1816 | goto misc_out; | |
1817 | } | |
1da177e4 | 1818 | |
d134b00b KS |
1819 | /* |
1820 | * If max_loop is specified, create that many devices upfront. | |
1821 | * This also becomes a hard limit. If max_loop is not specified, | |
1822 | * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module | |
1823 | * init time. Loop devices can be requested on-demand with the | |
1824 | * /dev/loop-control interface, or be instantiated by accessing | |
1825 | * a 'dead' device node. | |
1826 | */ | |
73285082 | 1827 | if (max_loop) { |
a47653fc | 1828 | nr = max_loop; |
a1c15c59 | 1829 | range = max_loop << part_shift; |
a47653fc | 1830 | } else { |
d134b00b | 1831 | nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; |
a1c15c59 | 1832 | range = 1UL << MINORBITS; |
a47653fc KC |
1833 | } |
1834 | ||
b1a66504 GC |
1835 | if (register_blkdev(LOOP_MAJOR, "loop")) { |
1836 | err = -EIO; | |
1837 | goto misc_out; | |
1838 | } | |
1da177e4 | 1839 | |
a47653fc KC |
1840 | blk_register_region(MKDEV(LOOP_MAJOR, 0), range, |
1841 | THIS_MODULE, loop_probe, NULL, NULL); | |
1842 | ||
d134b00b | 1843 | /* pre-create number of devices given by config or max_loop */ |
34dd82af KS |
1844 | mutex_lock(&loop_index_mutex); |
1845 | for (i = 0; i < nr; i++) | |
1846 | loop_add(&lo, i); | |
1847 | mutex_unlock(&loop_index_mutex); | |
1848 | ||
73285082 | 1849 | printk(KERN_INFO "loop: module loaded\n"); |
1da177e4 | 1850 | return 0; |
b1a66504 GC |
1851 | |
1852 | misc_out: | |
1853 | misc_deregister(&loop_misc); | |
1854 | return err; | |
34dd82af | 1855 | } |
a47653fc | 1856 | |
34dd82af KS |
1857 | static int loop_exit_cb(int id, void *ptr, void *data) |
1858 | { | |
1859 | struct loop_device *lo = ptr; | |
a47653fc | 1860 | |
34dd82af KS |
1861 | loop_remove(lo); |
1862 | return 0; | |
1da177e4 LT |
1863 | } |
1864 | ||
73285082 | 1865 | static void __exit loop_exit(void) |
1da177e4 | 1866 | { |
a47653fc | 1867 | unsigned long range; |
1da177e4 | 1868 | |
a1c15c59 | 1869 | range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; |
a47653fc | 1870 | |
34dd82af | 1871 | idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); |
34dd82af | 1872 | idr_destroy(&loop_index_idr); |
73285082 | 1873 | |
a47653fc | 1874 | blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); |
00d59405 | 1875 | unregister_blkdev(LOOP_MAJOR, "loop"); |
770fe30a KS |
1876 | |
1877 | misc_deregister(&loop_misc); | |
1da177e4 LT |
1878 | } |
1879 | ||
1880 | module_init(loop_init); | |
1881 | module_exit(loop_exit); | |
1882 | ||
1883 | #ifndef MODULE | |
1884 | static int __init max_loop_setup(char *str) | |
1885 | { | |
1886 | max_loop = simple_strtol(str, NULL, 0); | |
1887 | return 1; | |
1888 | } | |
1889 | ||
1890 | __setup("max_loop=", max_loop_setup); | |
1891 | #endif |