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