Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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. |
| 32 | * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999 |
| 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 |
| 43 | * operations prepare_write and/or commit_write are not available on the |
| 44 | * backing filesystem. |
| 45 | * Anton Altaparmakov, 16 Feb 2005 |
| 46 | * |
| 47 | * Still To Fix: |
| 48 | * - Advisory locking is ignored here. |
| 49 | * - Should use an own CAP_* category instead of CAP_SYS_ADMIN |
| 50 | * |
| 51 | */ |
| 52 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | #include <linux/module.h> |
| 54 | #include <linux/moduleparam.h> |
| 55 | #include <linux/sched.h> |
| 56 | #include <linux/fs.h> |
| 57 | #include <linux/file.h> |
| 58 | #include <linux/stat.h> |
| 59 | #include <linux/errno.h> |
| 60 | #include <linux/major.h> |
| 61 | #include <linux/wait.h> |
| 62 | #include <linux/blkdev.h> |
| 63 | #include <linux/blkpg.h> |
| 64 | #include <linux/init.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | #include <linux/smp_lock.h> |
| 66 | #include <linux/swap.h> |
| 67 | #include <linux/slab.h> |
| 68 | #include <linux/loop.h> |
| 69 | #include <linux/suspend.h> |
| 70 | #include <linux/writeback.h> |
| 71 | #include <linux/buffer_head.h> /* for invalidate_bdev() */ |
| 72 | #include <linux/completion.h> |
| 73 | #include <linux/highmem.h> |
| 74 | #include <linux/gfp.h> |
| 75 | |
| 76 | #include <asm/uaccess.h> |
| 77 | |
| 78 | static int max_loop = 8; |
| 79 | static struct loop_device *loop_dev; |
| 80 | static struct gendisk **disks; |
| 81 | |
| 82 | /* |
| 83 | * Transfer functions |
| 84 | */ |
| 85 | static int transfer_none(struct loop_device *lo, int cmd, |
| 86 | struct page *raw_page, unsigned raw_off, |
| 87 | struct page *loop_page, unsigned loop_off, |
| 88 | int size, sector_t real_block) |
| 89 | { |
| 90 | char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; |
| 91 | char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; |
| 92 | |
| 93 | if (cmd == READ) |
| 94 | memcpy(loop_buf, raw_buf, size); |
| 95 | else |
| 96 | memcpy(raw_buf, loop_buf, size); |
| 97 | |
| 98 | kunmap_atomic(raw_buf, KM_USER0); |
| 99 | kunmap_atomic(loop_buf, KM_USER1); |
| 100 | cond_resched(); |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | static int transfer_xor(struct loop_device *lo, int cmd, |
| 105 | struct page *raw_page, unsigned raw_off, |
| 106 | struct page *loop_page, unsigned loop_off, |
| 107 | int size, sector_t real_block) |
| 108 | { |
| 109 | char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; |
| 110 | char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; |
| 111 | char *in, *out, *key; |
| 112 | int i, keysize; |
| 113 | |
| 114 | if (cmd == READ) { |
| 115 | in = raw_buf; |
| 116 | out = loop_buf; |
| 117 | } else { |
| 118 | in = loop_buf; |
| 119 | out = raw_buf; |
| 120 | } |
| 121 | |
| 122 | key = lo->lo_encrypt_key; |
| 123 | keysize = lo->lo_encrypt_key_size; |
| 124 | for (i = 0; i < size; i++) |
| 125 | *out++ = *in++ ^ key[(i & 511) % keysize]; |
| 126 | |
| 127 | kunmap_atomic(raw_buf, KM_USER0); |
| 128 | kunmap_atomic(loop_buf, KM_USER1); |
| 129 | cond_resched(); |
| 130 | return 0; |
| 131 | } |
| 132 | |
| 133 | static int xor_init(struct loop_device *lo, const struct loop_info64 *info) |
| 134 | { |
| 135 | if (unlikely(info->lo_encrypt_key_size <= 0)) |
| 136 | return -EINVAL; |
| 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | static struct loop_func_table none_funcs = { |
| 141 | .number = LO_CRYPT_NONE, |
| 142 | .transfer = transfer_none, |
| 143 | }; |
| 144 | |
| 145 | static struct loop_func_table xor_funcs = { |
| 146 | .number = LO_CRYPT_XOR, |
| 147 | .transfer = transfer_xor, |
| 148 | .init = xor_init |
| 149 | }; |
| 150 | |
| 151 | /* xfer_funcs[0] is special - its release function is never called */ |
| 152 | static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { |
| 153 | &none_funcs, |
| 154 | &xor_funcs |
| 155 | }; |
| 156 | |
| 157 | static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
| 158 | { |
| 159 | loff_t size, offset, loopsize; |
| 160 | |
| 161 | /* Compute loopsize in bytes */ |
| 162 | size = i_size_read(file->f_mapping->host); |
| 163 | offset = lo->lo_offset; |
| 164 | loopsize = size - offset; |
| 165 | if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize) |
| 166 | loopsize = lo->lo_sizelimit; |
| 167 | |
| 168 | /* |
| 169 | * Unfortunately, if we want to do I/O on the device, |
| 170 | * the number of 512-byte sectors has to fit into a sector_t. |
| 171 | */ |
| 172 | return loopsize >> 9; |
| 173 | } |
| 174 | |
| 175 | static int |
| 176 | figure_loop_size(struct loop_device *lo) |
| 177 | { |
| 178 | loff_t size = get_loop_size(lo, lo->lo_backing_file); |
| 179 | sector_t x = (sector_t)size; |
| 180 | |
| 181 | if (unlikely((loff_t)x != size)) |
| 182 | return -EFBIG; |
| 183 | |
| 184 | set_capacity(disks[lo->lo_number], x); |
| 185 | return 0; |
| 186 | } |
| 187 | |
| 188 | static inline int |
| 189 | lo_do_transfer(struct loop_device *lo, int cmd, |
| 190 | struct page *rpage, unsigned roffs, |
| 191 | struct page *lpage, unsigned loffs, |
| 192 | int size, sector_t rblock) |
| 193 | { |
| 194 | if (unlikely(!lo->transfer)) |
| 195 | return 0; |
| 196 | |
| 197 | return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); |
| 198 | } |
| 199 | |
| 200 | /** |
| 201 | * do_lo_send_aops - helper for writing data to a loop device |
| 202 | * |
| 203 | * This is the fast version for backing filesystems which implement the address |
| 204 | * space operations prepare_write and commit_write. |
| 205 | */ |
| 206 | static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, |
| 207 | int bsize, loff_t pos, struct page *page) |
| 208 | { |
| 209 | struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */ |
| 210 | struct address_space *mapping = file->f_mapping; |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 211 | const struct address_space_operations *aops = mapping->a_ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | pgoff_t index; |
| 213 | unsigned offset, bv_offs; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 214 | int len, ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 216 | mutex_lock(&mapping->host->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | index = pos >> PAGE_CACHE_SHIFT; |
| 218 | offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1); |
| 219 | bv_offs = bvec->bv_offset; |
| 220 | len = bvec->bv_len; |
| 221 | while (len > 0) { |
| 222 | sector_t IV; |
| 223 | unsigned size; |
| 224 | int transfer_result; |
| 225 | |
| 226 | IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); |
| 227 | size = PAGE_CACHE_SIZE - offset; |
| 228 | if (size > len) |
| 229 | size = len; |
| 230 | page = grab_cache_page(mapping, index); |
| 231 | if (unlikely(!page)) |
| 232 | goto fail; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 233 | ret = aops->prepare_write(file, page, offset, |
| 234 | offset + size); |
| 235 | if (unlikely(ret)) { |
| 236 | if (ret == AOP_TRUNCATED_PAGE) { |
| 237 | page_cache_release(page); |
| 238 | continue; |
| 239 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | goto unlock; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 241 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | transfer_result = lo_do_transfer(lo, WRITE, page, offset, |
| 243 | bvec->bv_page, bv_offs, size, IV); |
| 244 | if (unlikely(transfer_result)) { |
| 245 | char *kaddr; |
| 246 | |
| 247 | /* |
| 248 | * The transfer failed, but we still write the data to |
| 249 | * keep prepare/commit calls balanced. |
| 250 | */ |
| 251 | printk(KERN_ERR "loop: transfer error block %llu\n", |
| 252 | (unsigned long long)index); |
| 253 | kaddr = kmap_atomic(page, KM_USER0); |
| 254 | memset(kaddr + offset, 0, size); |
| 255 | kunmap_atomic(kaddr, KM_USER0); |
| 256 | } |
| 257 | flush_dcache_page(page); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 258 | ret = aops->commit_write(file, page, offset, |
| 259 | offset + size); |
| 260 | if (unlikely(ret)) { |
| 261 | if (ret == AOP_TRUNCATED_PAGE) { |
| 262 | page_cache_release(page); |
| 263 | continue; |
| 264 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | goto unlock; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 266 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | if (unlikely(transfer_result)) |
| 268 | goto unlock; |
| 269 | bv_offs += size; |
| 270 | len -= size; |
| 271 | offset = 0; |
| 272 | index++; |
| 273 | pos += size; |
| 274 | unlock_page(page); |
| 275 | page_cache_release(page); |
| 276 | } |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 277 | ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | out: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 279 | mutex_unlock(&mapping->host->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | return ret; |
| 281 | unlock: |
| 282 | unlock_page(page); |
| 283 | page_cache_release(page); |
| 284 | fail: |
| 285 | ret = -1; |
| 286 | goto out; |
| 287 | } |
| 288 | |
| 289 | /** |
| 290 | * __do_lo_send_write - helper for writing data to a loop device |
| 291 | * |
| 292 | * This helper just factors out common code between do_lo_send_direct_write() |
| 293 | * and do_lo_send_write(). |
| 294 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 295 | static int __do_lo_send_write(struct file *file, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | u8 __user *buf, const int len, loff_t pos) |
| 297 | { |
| 298 | ssize_t bw; |
| 299 | mm_segment_t old_fs = get_fs(); |
| 300 | |
| 301 | set_fs(get_ds()); |
| 302 | bw = file->f_op->write(file, buf, len, &pos); |
| 303 | set_fs(old_fs); |
| 304 | if (likely(bw == len)) |
| 305 | return 0; |
| 306 | printk(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", |
| 307 | (unsigned long long)pos, len); |
| 308 | if (bw >= 0) |
| 309 | bw = -EIO; |
| 310 | return bw; |
| 311 | } |
| 312 | |
| 313 | /** |
| 314 | * do_lo_send_direct_write - helper for writing data to a loop device |
| 315 | * |
| 316 | * This is the fast, non-transforming version for backing filesystems which do |
| 317 | * not implement the address space operations prepare_write and commit_write. |
| 318 | * It uses the write file operation which should be present on all writeable |
| 319 | * filesystems. |
| 320 | */ |
| 321 | static int do_lo_send_direct_write(struct loop_device *lo, |
| 322 | struct bio_vec *bvec, int bsize, loff_t pos, struct page *page) |
| 323 | { |
| 324 | ssize_t bw = __do_lo_send_write(lo->lo_backing_file, |
| 325 | (u8 __user *)kmap(bvec->bv_page) + bvec->bv_offset, |
| 326 | bvec->bv_len, pos); |
| 327 | kunmap(bvec->bv_page); |
| 328 | cond_resched(); |
| 329 | return bw; |
| 330 | } |
| 331 | |
| 332 | /** |
| 333 | * do_lo_send_write - helper for writing data to a loop device |
| 334 | * |
| 335 | * This is the slow, transforming version for filesystems which do not |
| 336 | * implement the address space operations prepare_write and commit_write. It |
| 337 | * uses the write file operation which should be present on all writeable |
| 338 | * filesystems. |
| 339 | * |
| 340 | * Using fops->write is slower than using aops->{prepare,commit}_write in the |
| 341 | * transforming case because we need to double buffer the data as we cannot do |
| 342 | * the transformations in place as we do not have direct access to the |
| 343 | * destination pages of the backing file. |
| 344 | */ |
| 345 | static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, |
| 346 | int bsize, loff_t pos, struct page *page) |
| 347 | { |
| 348 | int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, |
| 349 | bvec->bv_offset, bvec->bv_len, pos >> 9); |
| 350 | if (likely(!ret)) |
| 351 | return __do_lo_send_write(lo->lo_backing_file, |
| 352 | (u8 __user *)page_address(page), bvec->bv_len, |
| 353 | pos); |
| 354 | printk(KERN_ERR "loop: Transfer error at byte offset %llu, " |
| 355 | "length %i.\n", (unsigned long long)pos, bvec->bv_len); |
| 356 | if (ret > 0) |
| 357 | ret = -EIO; |
| 358 | return ret; |
| 359 | } |
| 360 | |
| 361 | static int lo_send(struct loop_device *lo, struct bio *bio, int bsize, |
| 362 | loff_t pos) |
| 363 | { |
| 364 | int (*do_lo_send)(struct loop_device *, struct bio_vec *, int, loff_t, |
| 365 | struct page *page); |
| 366 | struct bio_vec *bvec; |
| 367 | struct page *page = NULL; |
| 368 | int i, ret = 0; |
| 369 | |
| 370 | do_lo_send = do_lo_send_aops; |
| 371 | if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) { |
| 372 | do_lo_send = do_lo_send_direct_write; |
| 373 | if (lo->transfer != transfer_none) { |
| 374 | page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); |
| 375 | if (unlikely(!page)) |
| 376 | goto fail; |
| 377 | kmap(page); |
| 378 | do_lo_send = do_lo_send_write; |
| 379 | } |
| 380 | } |
| 381 | bio_for_each_segment(bvec, bio, i) { |
| 382 | ret = do_lo_send(lo, bvec, bsize, pos, page); |
| 383 | if (ret < 0) |
| 384 | break; |
| 385 | pos += bvec->bv_len; |
| 386 | } |
| 387 | if (page) { |
| 388 | kunmap(page); |
| 389 | __free_page(page); |
| 390 | } |
| 391 | out: |
| 392 | return ret; |
| 393 | fail: |
| 394 | printk(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); |
| 395 | ret = -ENOMEM; |
| 396 | goto out; |
| 397 | } |
| 398 | |
| 399 | struct lo_read_data { |
| 400 | struct loop_device *lo; |
| 401 | struct page *page; |
| 402 | unsigned offset; |
| 403 | int bsize; |
| 404 | }; |
| 405 | |
| 406 | static int |
| 407 | lo_read_actor(read_descriptor_t *desc, struct page *page, |
| 408 | unsigned long offset, unsigned long size) |
| 409 | { |
| 410 | unsigned long count = desc->count; |
| 411 | struct lo_read_data *p = desc->arg.data; |
| 412 | struct loop_device *lo = p->lo; |
| 413 | sector_t IV; |
| 414 | |
| 415 | IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); |
| 416 | |
| 417 | if (size > count) |
| 418 | size = count; |
| 419 | |
| 420 | if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) { |
| 421 | size = 0; |
| 422 | printk(KERN_ERR "loop: transfer error block %ld\n", |
| 423 | page->index); |
| 424 | desc->error = -EINVAL; |
| 425 | } |
| 426 | |
| 427 | flush_dcache_page(p->page); |
| 428 | |
| 429 | desc->count = count - size; |
| 430 | desc->written += size; |
| 431 | p->offset += size; |
| 432 | return size; |
| 433 | } |
| 434 | |
| 435 | static int |
| 436 | do_lo_receive(struct loop_device *lo, |
| 437 | struct bio_vec *bvec, int bsize, loff_t pos) |
| 438 | { |
| 439 | struct lo_read_data cookie; |
| 440 | struct file *file; |
| 441 | int retval; |
| 442 | |
| 443 | cookie.lo = lo; |
| 444 | cookie.page = bvec->bv_page; |
| 445 | cookie.offset = bvec->bv_offset; |
| 446 | cookie.bsize = bsize; |
| 447 | file = lo->lo_backing_file; |
| 448 | retval = file->f_op->sendfile(file, &pos, bvec->bv_len, |
| 449 | lo_read_actor, &cookie); |
| 450 | return (retval < 0)? retval: 0; |
| 451 | } |
| 452 | |
| 453 | static int |
| 454 | lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos) |
| 455 | { |
| 456 | struct bio_vec *bvec; |
| 457 | int i, ret = 0; |
| 458 | |
| 459 | bio_for_each_segment(bvec, bio, i) { |
| 460 | ret = do_lo_receive(lo, bvec, bsize, pos); |
| 461 | if (ret < 0) |
| 462 | break; |
| 463 | pos += bvec->bv_len; |
| 464 | } |
| 465 | return ret; |
| 466 | } |
| 467 | |
| 468 | static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) |
| 469 | { |
| 470 | loff_t pos; |
| 471 | int ret; |
| 472 | |
| 473 | pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; |
| 474 | if (bio_rw(bio) == WRITE) |
| 475 | ret = lo_send(lo, bio, lo->lo_blocksize, pos); |
| 476 | else |
| 477 | ret = lo_receive(lo, bio, lo->lo_blocksize, pos); |
| 478 | return ret; |
| 479 | } |
| 480 | |
| 481 | /* |
| 482 | * Add bio to back of pending list |
| 483 | */ |
| 484 | static void loop_add_bio(struct loop_device *lo, struct bio *bio) |
| 485 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | if (lo->lo_biotail) { |
| 487 | lo->lo_biotail->bi_next = bio; |
| 488 | lo->lo_biotail = bio; |
| 489 | } else |
| 490 | lo->lo_bio = lo->lo_biotail = bio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | } |
| 492 | |
| 493 | /* |
| 494 | * Grab first pending buffer |
| 495 | */ |
| 496 | static struct bio *loop_get_bio(struct loop_device *lo) |
| 497 | { |
| 498 | struct bio *bio; |
| 499 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | if ((bio = lo->lo_bio)) { |
| 501 | if (bio == lo->lo_biotail) |
| 502 | lo->lo_biotail = NULL; |
| 503 | lo->lo_bio = bio->bi_next; |
| 504 | bio->bi_next = NULL; |
| 505 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | |
| 507 | return bio; |
| 508 | } |
| 509 | |
| 510 | static int loop_make_request(request_queue_t *q, struct bio *old_bio) |
| 511 | { |
| 512 | struct loop_device *lo = q->queuedata; |
| 513 | int rw = bio_rw(old_bio); |
| 514 | |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 515 | if (rw == READA) |
| 516 | rw = READ; |
| 517 | |
| 518 | BUG_ON(!lo || (rw != READ && rw != WRITE)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | |
| 520 | spin_lock_irq(&lo->lo_lock); |
| 521 | if (lo->lo_state != Lo_bound) |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 522 | goto out; |
| 523 | if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY))) |
| 524 | goto out; |
| 525 | lo->lo_pending++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | loop_add_bio(lo, old_bio); |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 527 | spin_unlock_irq(&lo->lo_lock); |
Ingo Molnar | 11b751a | 2006-01-09 15:59:27 -0800 | [diff] [blame] | 528 | complete(&lo->lo_bh_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | return 0; |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 530 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | out: |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 532 | if (lo->lo_pending == 0) |
Ingo Molnar | 11b751a | 2006-01-09 15:59:27 -0800 | [diff] [blame] | 533 | complete(&lo->lo_bh_done); |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 534 | spin_unlock_irq(&lo->lo_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | bio_io_error(old_bio, old_bio->bi_size); |
| 536 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | } |
| 538 | |
| 539 | /* |
| 540 | * kick off io on the underlying address space |
| 541 | */ |
| 542 | static void loop_unplug(request_queue_t *q) |
| 543 | { |
| 544 | struct loop_device *lo = q->queuedata; |
| 545 | |
| 546 | clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags); |
| 547 | blk_run_address_space(lo->lo_backing_file->f_mapping); |
| 548 | } |
| 549 | |
| 550 | struct switch_request { |
| 551 | struct file *file; |
| 552 | struct completion wait; |
| 553 | }; |
| 554 | |
| 555 | static void do_loop_switch(struct loop_device *, struct switch_request *); |
| 556 | |
| 557 | static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) |
| 558 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | if (unlikely(!bio->bi_bdev)) { |
| 560 | do_loop_switch(lo, bio->bi_private); |
| 561 | bio_put(bio); |
| 562 | } else { |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 563 | int ret = do_bio_filebacked(lo, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | bio_endio(bio, bio->bi_size, ret); |
| 565 | } |
| 566 | } |
| 567 | |
| 568 | /* |
| 569 | * worker thread that handles reads/writes to file backed loop devices, |
| 570 | * to avoid blocking in our make_request_fn. it also does loop decrypting |
| 571 | * on reads for block backed loop, as that is too heavy to do from |
| 572 | * b_end_io context where irqs may be disabled. |
| 573 | */ |
| 574 | static int loop_thread(void *data) |
| 575 | { |
| 576 | struct loop_device *lo = data; |
| 577 | struct bio *bio; |
| 578 | |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 579 | daemonize("loop%d", lo->lo_number); |
| 580 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | /* |
| 582 | * loop can be used in an encrypted device, |
| 583 | * hence, it mustn't be stopped at all |
| 584 | * because it could be indirectly used during suspension |
| 585 | */ |
| 586 | current->flags |= PF_NOFREEZE; |
| 587 | |
| 588 | set_user_nice(current, -20); |
| 589 | |
| 590 | lo->lo_state = Lo_bound; |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 591 | lo->lo_pending = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 593 | /* |
| 594 | * complete it, we are running |
| 595 | */ |
| 596 | complete(&lo->lo_done); |
| 597 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | for (;;) { |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 599 | int pending; |
| 600 | |
Ingo Molnar | 11b751a | 2006-01-09 15:59:27 -0800 | [diff] [blame] | 601 | if (wait_for_completion_interruptible(&lo->lo_bh_done)) |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 602 | continue; |
| 603 | |
| 604 | spin_lock_irq(&lo->lo_lock); |
| 605 | |
| 606 | /* |
Ingo Molnar | 11b751a | 2006-01-09 15:59:27 -0800 | [diff] [blame] | 607 | * could be completed because of tear-down, not pending work |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 608 | */ |
| 609 | if (unlikely(!lo->lo_pending)) { |
| 610 | spin_unlock_irq(&lo->lo_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | break; |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 612 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 613 | |
| 614 | bio = loop_get_bio(lo); |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 615 | lo->lo_pending--; |
| 616 | pending = lo->lo_pending; |
| 617 | spin_unlock_irq(&lo->lo_lock); |
| 618 | |
| 619 | BUG_ON(!bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | loop_handle_bio(lo, bio); |
| 621 | |
| 622 | /* |
| 623 | * upped both for pending work and tear-down, lo_pending |
| 624 | * will hit zero then |
| 625 | */ |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 626 | if (unlikely(!pending)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | break; |
| 628 | } |
| 629 | |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 630 | complete(&lo->lo_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | return 0; |
| 632 | } |
| 633 | |
| 634 | /* |
| 635 | * loop_switch performs the hard work of switching a backing store. |
| 636 | * First it needs to flush existing IO, it does this by sending a magic |
| 637 | * BIO down the pipe. The completion of this BIO does the actual switch. |
| 638 | */ |
| 639 | static int loop_switch(struct loop_device *lo, struct file *file) |
| 640 | { |
| 641 | struct switch_request w; |
| 642 | struct bio *bio = bio_alloc(GFP_KERNEL, 1); |
| 643 | if (!bio) |
| 644 | return -ENOMEM; |
| 645 | init_completion(&w.wait); |
| 646 | w.file = file; |
| 647 | bio->bi_private = &w; |
| 648 | bio->bi_bdev = NULL; |
| 649 | loop_make_request(lo->lo_queue, bio); |
| 650 | wait_for_completion(&w.wait); |
| 651 | return 0; |
| 652 | } |
| 653 | |
| 654 | /* |
| 655 | * Do the actual switch; called from the BIO completion routine |
| 656 | */ |
| 657 | static void do_loop_switch(struct loop_device *lo, struct switch_request *p) |
| 658 | { |
| 659 | struct file *file = p->file; |
| 660 | struct file *old_file = lo->lo_backing_file; |
| 661 | struct address_space *mapping = file->f_mapping; |
| 662 | |
| 663 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); |
| 664 | lo->lo_backing_file = file; |
| 665 | lo->lo_blocksize = mapping->host->i_blksize; |
| 666 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
| 667 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
| 668 | complete(&p->wait); |
| 669 | } |
| 670 | |
| 671 | |
| 672 | /* |
| 673 | * loop_change_fd switched the backing store of a loopback device to |
| 674 | * a new file. This is useful for operating system installers to free up |
| 675 | * the original file and in High Availability environments to switch to |
| 676 | * an alternative location for the content in case of server meltdown. |
| 677 | * This can only work if the loop device is used read-only, and if the |
| 678 | * new backing store is the same size and type as the old backing store. |
| 679 | */ |
| 680 | static int loop_change_fd(struct loop_device *lo, struct file *lo_file, |
| 681 | struct block_device *bdev, unsigned int arg) |
| 682 | { |
| 683 | struct file *file, *old_file; |
| 684 | struct inode *inode; |
| 685 | int error; |
| 686 | |
| 687 | error = -ENXIO; |
| 688 | if (lo->lo_state != Lo_bound) |
| 689 | goto out; |
| 690 | |
| 691 | /* the loop device has to be read-only */ |
| 692 | error = -EINVAL; |
| 693 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) |
| 694 | goto out; |
| 695 | |
| 696 | error = -EBADF; |
| 697 | file = fget(arg); |
| 698 | if (!file) |
| 699 | goto out; |
| 700 | |
| 701 | inode = file->f_mapping->host; |
| 702 | old_file = lo->lo_backing_file; |
| 703 | |
| 704 | error = -EINVAL; |
| 705 | |
| 706 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
| 707 | goto out_putf; |
| 708 | |
| 709 | /* new backing store needs to support loop (eg sendfile) */ |
| 710 | if (!inode->i_fop->sendfile) |
| 711 | goto out_putf; |
| 712 | |
| 713 | /* size of the new backing store needs to be the same */ |
| 714 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) |
| 715 | goto out_putf; |
| 716 | |
| 717 | /* and ... switch */ |
| 718 | error = loop_switch(lo, file); |
| 719 | if (error) |
| 720 | goto out_putf; |
| 721 | |
| 722 | fput(old_file); |
| 723 | return 0; |
| 724 | |
| 725 | out_putf: |
| 726 | fput(file); |
| 727 | out: |
| 728 | return error; |
| 729 | } |
| 730 | |
| 731 | static inline int is_loop_device(struct file *file) |
| 732 | { |
| 733 | struct inode *i = file->f_mapping->host; |
| 734 | |
| 735 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; |
| 736 | } |
| 737 | |
| 738 | static int loop_set_fd(struct loop_device *lo, struct file *lo_file, |
| 739 | struct block_device *bdev, unsigned int arg) |
| 740 | { |
| 741 | struct file *file, *f; |
| 742 | struct inode *inode; |
| 743 | struct address_space *mapping; |
| 744 | unsigned lo_blocksize; |
| 745 | int lo_flags = 0; |
| 746 | int error; |
| 747 | loff_t size; |
| 748 | |
| 749 | /* This is safe, since we have a reference from open(). */ |
| 750 | __module_get(THIS_MODULE); |
| 751 | |
| 752 | error = -EBADF; |
| 753 | file = fget(arg); |
| 754 | if (!file) |
| 755 | goto out; |
| 756 | |
| 757 | error = -EBUSY; |
| 758 | if (lo->lo_state != Lo_unbound) |
| 759 | goto out_putf; |
| 760 | |
| 761 | /* Avoid recursion */ |
| 762 | f = file; |
| 763 | while (is_loop_device(f)) { |
| 764 | struct loop_device *l; |
| 765 | |
| 766 | if (f->f_mapping->host->i_rdev == lo_file->f_mapping->host->i_rdev) |
| 767 | goto out_putf; |
| 768 | |
| 769 | l = f->f_mapping->host->i_bdev->bd_disk->private_data; |
| 770 | if (l->lo_state == Lo_unbound) { |
| 771 | error = -EINVAL; |
| 772 | goto out_putf; |
| 773 | } |
| 774 | f = l->lo_backing_file; |
| 775 | } |
| 776 | |
| 777 | mapping = file->f_mapping; |
| 778 | inode = mapping->host; |
| 779 | |
| 780 | if (!(file->f_mode & FMODE_WRITE)) |
| 781 | lo_flags |= LO_FLAGS_READ_ONLY; |
| 782 | |
| 783 | error = -EINVAL; |
| 784 | if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) { |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 785 | const struct address_space_operations *aops = mapping->a_ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 786 | /* |
| 787 | * If we can't read - sorry. If we only can't write - well, |
| 788 | * it's going to be read-only. |
| 789 | */ |
| 790 | if (!file->f_op->sendfile) |
| 791 | goto out_putf; |
| 792 | if (aops->prepare_write && aops->commit_write) |
| 793 | lo_flags |= LO_FLAGS_USE_AOPS; |
| 794 | if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write) |
| 795 | lo_flags |= LO_FLAGS_READ_ONLY; |
| 796 | |
| 797 | lo_blocksize = inode->i_blksize; |
| 798 | error = 0; |
| 799 | } else { |
| 800 | goto out_putf; |
| 801 | } |
| 802 | |
| 803 | size = get_loop_size(lo, file); |
| 804 | |
| 805 | if ((loff_t)(sector_t)size != size) { |
| 806 | error = -EFBIG; |
| 807 | goto out_putf; |
| 808 | } |
| 809 | |
| 810 | if (!(lo_file->f_mode & FMODE_WRITE)) |
| 811 | lo_flags |= LO_FLAGS_READ_ONLY; |
| 812 | |
| 813 | set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); |
| 814 | |
| 815 | lo->lo_blocksize = lo_blocksize; |
| 816 | lo->lo_device = bdev; |
| 817 | lo->lo_flags = lo_flags; |
| 818 | lo->lo_backing_file = file; |
Constantine Sapuntzakis | eefe85e | 2006-06-23 02:06:08 -0700 | [diff] [blame] | 819 | lo->transfer = transfer_none; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | lo->ioctl = NULL; |
| 821 | lo->lo_sizelimit = 0; |
| 822 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
| 823 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
| 824 | |
| 825 | lo->lo_bio = lo->lo_biotail = NULL; |
| 826 | |
| 827 | /* |
| 828 | * set queue make_request_fn, and add limits based on lower level |
| 829 | * device |
| 830 | */ |
| 831 | blk_queue_make_request(lo->lo_queue, loop_make_request); |
| 832 | lo->lo_queue->queuedata = lo; |
| 833 | lo->lo_queue->unplug_fn = loop_unplug; |
| 834 | |
| 835 | set_capacity(disks[lo->lo_number], size); |
| 836 | bd_set_size(bdev, size << 9); |
| 837 | |
| 838 | set_blocksize(bdev, lo_blocksize); |
| 839 | |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 840 | error = kernel_thread(loop_thread, lo, CLONE_KERNEL); |
| 841 | if (error < 0) |
Herbert Poetzl | 3e88c17 | 2006-03-26 01:37:30 -0800 | [diff] [blame] | 842 | goto out_putf; |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 843 | wait_for_completion(&lo->lo_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | return 0; |
| 845 | |
| 846 | out_putf: |
| 847 | fput(file); |
| 848 | out: |
| 849 | /* This is safe: open() is still holding a reference. */ |
| 850 | module_put(THIS_MODULE); |
| 851 | return error; |
| 852 | } |
| 853 | |
| 854 | static int |
| 855 | loop_release_xfer(struct loop_device *lo) |
| 856 | { |
| 857 | int err = 0; |
| 858 | struct loop_func_table *xfer = lo->lo_encryption; |
| 859 | |
| 860 | if (xfer) { |
| 861 | if (xfer->release) |
| 862 | err = xfer->release(lo); |
| 863 | lo->transfer = NULL; |
| 864 | lo->lo_encryption = NULL; |
| 865 | module_put(xfer->owner); |
| 866 | } |
| 867 | return err; |
| 868 | } |
| 869 | |
| 870 | static int |
| 871 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, |
| 872 | const struct loop_info64 *i) |
| 873 | { |
| 874 | int err = 0; |
| 875 | |
| 876 | if (xfer) { |
| 877 | struct module *owner = xfer->owner; |
| 878 | |
| 879 | if (!try_module_get(owner)) |
| 880 | return -EINVAL; |
| 881 | if (xfer->init) |
| 882 | err = xfer->init(lo, i); |
| 883 | if (err) |
| 884 | module_put(owner); |
| 885 | else |
| 886 | lo->lo_encryption = xfer; |
| 887 | } |
| 888 | return err; |
| 889 | } |
| 890 | |
| 891 | static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) |
| 892 | { |
| 893 | struct file *filp = lo->lo_backing_file; |
Al Viro | b4e3ca1 | 2005-10-21 03:22:34 -0400 | [diff] [blame] | 894 | gfp_t gfp = lo->old_gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 895 | |
| 896 | if (lo->lo_state != Lo_bound) |
| 897 | return -ENXIO; |
| 898 | |
| 899 | if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */ |
| 900 | return -EBUSY; |
| 901 | |
| 902 | if (filp == NULL) |
| 903 | return -EINVAL; |
| 904 | |
| 905 | spin_lock_irq(&lo->lo_lock); |
| 906 | lo->lo_state = Lo_rundown; |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 907 | lo->lo_pending--; |
| 908 | if (!lo->lo_pending) |
Ingo Molnar | 11b751a | 2006-01-09 15:59:27 -0800 | [diff] [blame] | 909 | complete(&lo->lo_bh_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | spin_unlock_irq(&lo->lo_lock); |
| 911 | |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 912 | wait_for_completion(&lo->lo_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 913 | |
| 914 | lo->lo_backing_file = NULL; |
| 915 | |
| 916 | loop_release_xfer(lo); |
| 917 | lo->transfer = NULL; |
| 918 | lo->ioctl = NULL; |
| 919 | lo->lo_device = NULL; |
| 920 | lo->lo_encryption = NULL; |
| 921 | lo->lo_offset = 0; |
| 922 | lo->lo_sizelimit = 0; |
| 923 | lo->lo_encrypt_key_size = 0; |
| 924 | lo->lo_flags = 0; |
| 925 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
| 926 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); |
| 927 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); |
| 928 | invalidate_bdev(bdev, 0); |
| 929 | set_capacity(disks[lo->lo_number], 0); |
| 930 | bd_set_size(bdev, 0); |
| 931 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
| 932 | lo->lo_state = Lo_unbound; |
| 933 | fput(filp); |
| 934 | /* This is safe: open() is still holding a reference. */ |
| 935 | module_put(THIS_MODULE); |
| 936 | return 0; |
| 937 | } |
| 938 | |
| 939 | static int |
| 940 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) |
| 941 | { |
| 942 | int err; |
| 943 | struct loop_func_table *xfer; |
| 944 | |
| 945 | if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid && |
| 946 | !capable(CAP_SYS_ADMIN)) |
| 947 | return -EPERM; |
| 948 | if (lo->lo_state != Lo_bound) |
| 949 | return -ENXIO; |
| 950 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) |
| 951 | return -EINVAL; |
| 952 | |
| 953 | err = loop_release_xfer(lo); |
| 954 | if (err) |
| 955 | return err; |
| 956 | |
| 957 | if (info->lo_encrypt_type) { |
| 958 | unsigned int type = info->lo_encrypt_type; |
| 959 | |
| 960 | if (type >= MAX_LO_CRYPT) |
| 961 | return -EINVAL; |
| 962 | xfer = xfer_funcs[type]; |
| 963 | if (xfer == NULL) |
| 964 | return -EINVAL; |
| 965 | } else |
| 966 | xfer = NULL; |
| 967 | |
| 968 | err = loop_init_xfer(lo, xfer, info); |
| 969 | if (err) |
| 970 | return err; |
| 971 | |
| 972 | if (lo->lo_offset != info->lo_offset || |
| 973 | lo->lo_sizelimit != info->lo_sizelimit) { |
| 974 | lo->lo_offset = info->lo_offset; |
| 975 | lo->lo_sizelimit = info->lo_sizelimit; |
| 976 | if (figure_loop_size(lo)) |
| 977 | return -EFBIG; |
| 978 | } |
| 979 | |
| 980 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); |
| 981 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); |
| 982 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; |
| 983 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; |
| 984 | |
| 985 | if (!xfer) |
| 986 | xfer = &none_funcs; |
| 987 | lo->transfer = xfer->transfer; |
| 988 | lo->ioctl = xfer->ioctl; |
| 989 | |
| 990 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; |
| 991 | lo->lo_init[0] = info->lo_init[0]; |
| 992 | lo->lo_init[1] = info->lo_init[1]; |
| 993 | if (info->lo_encrypt_key_size) { |
| 994 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, |
| 995 | info->lo_encrypt_key_size); |
| 996 | lo->lo_key_owner = current->uid; |
| 997 | } |
| 998 | |
| 999 | return 0; |
| 1000 | } |
| 1001 | |
| 1002 | static int |
| 1003 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) |
| 1004 | { |
| 1005 | struct file *file = lo->lo_backing_file; |
| 1006 | struct kstat stat; |
| 1007 | int error; |
| 1008 | |
| 1009 | if (lo->lo_state != Lo_bound) |
| 1010 | return -ENXIO; |
| 1011 | error = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat); |
| 1012 | if (error) |
| 1013 | return error; |
| 1014 | memset(info, 0, sizeof(*info)); |
| 1015 | info->lo_number = lo->lo_number; |
| 1016 | info->lo_device = huge_encode_dev(stat.dev); |
| 1017 | info->lo_inode = stat.ino; |
| 1018 | info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev); |
| 1019 | info->lo_offset = lo->lo_offset; |
| 1020 | info->lo_sizelimit = lo->lo_sizelimit; |
| 1021 | info->lo_flags = lo->lo_flags; |
| 1022 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); |
| 1023 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); |
| 1024 | info->lo_encrypt_type = |
| 1025 | lo->lo_encryption ? lo->lo_encryption->number : 0; |
| 1026 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { |
| 1027 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; |
| 1028 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, |
| 1029 | lo->lo_encrypt_key_size); |
| 1030 | } |
| 1031 | return 0; |
| 1032 | } |
| 1033 | |
| 1034 | static void |
| 1035 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) |
| 1036 | { |
| 1037 | memset(info64, 0, sizeof(*info64)); |
| 1038 | info64->lo_number = info->lo_number; |
| 1039 | info64->lo_device = info->lo_device; |
| 1040 | info64->lo_inode = info->lo_inode; |
| 1041 | info64->lo_rdevice = info->lo_rdevice; |
| 1042 | info64->lo_offset = info->lo_offset; |
| 1043 | info64->lo_sizelimit = 0; |
| 1044 | info64->lo_encrypt_type = info->lo_encrypt_type; |
| 1045 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; |
| 1046 | info64->lo_flags = info->lo_flags; |
| 1047 | info64->lo_init[0] = info->lo_init[0]; |
| 1048 | info64->lo_init[1] = info->lo_init[1]; |
| 1049 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) |
| 1050 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); |
| 1051 | else |
| 1052 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); |
| 1053 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); |
| 1054 | } |
| 1055 | |
| 1056 | static int |
| 1057 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) |
| 1058 | { |
| 1059 | memset(info, 0, sizeof(*info)); |
| 1060 | info->lo_number = info64->lo_number; |
| 1061 | info->lo_device = info64->lo_device; |
| 1062 | info->lo_inode = info64->lo_inode; |
| 1063 | info->lo_rdevice = info64->lo_rdevice; |
| 1064 | info->lo_offset = info64->lo_offset; |
| 1065 | info->lo_encrypt_type = info64->lo_encrypt_type; |
| 1066 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; |
| 1067 | info->lo_flags = info64->lo_flags; |
| 1068 | info->lo_init[0] = info64->lo_init[0]; |
| 1069 | info->lo_init[1] = info64->lo_init[1]; |
| 1070 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) |
| 1071 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); |
| 1072 | else |
| 1073 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); |
| 1074 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); |
| 1075 | |
| 1076 | /* error in case values were truncated */ |
| 1077 | if (info->lo_device != info64->lo_device || |
| 1078 | info->lo_rdevice != info64->lo_rdevice || |
| 1079 | info->lo_inode != info64->lo_inode || |
| 1080 | info->lo_offset != info64->lo_offset) |
| 1081 | return -EOVERFLOW; |
| 1082 | |
| 1083 | return 0; |
| 1084 | } |
| 1085 | |
| 1086 | static int |
| 1087 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) |
| 1088 | { |
| 1089 | struct loop_info info; |
| 1090 | struct loop_info64 info64; |
| 1091 | |
| 1092 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) |
| 1093 | return -EFAULT; |
| 1094 | loop_info64_from_old(&info, &info64); |
| 1095 | return loop_set_status(lo, &info64); |
| 1096 | } |
| 1097 | |
| 1098 | static int |
| 1099 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) |
| 1100 | { |
| 1101 | struct loop_info64 info64; |
| 1102 | |
| 1103 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) |
| 1104 | return -EFAULT; |
| 1105 | return loop_set_status(lo, &info64); |
| 1106 | } |
| 1107 | |
| 1108 | static int |
| 1109 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { |
| 1110 | struct loop_info info; |
| 1111 | struct loop_info64 info64; |
| 1112 | int err = 0; |
| 1113 | |
| 1114 | if (!arg) |
| 1115 | err = -EINVAL; |
| 1116 | if (!err) |
| 1117 | err = loop_get_status(lo, &info64); |
| 1118 | if (!err) |
| 1119 | err = loop_info64_to_old(&info64, &info); |
| 1120 | if (!err && copy_to_user(arg, &info, sizeof(info))) |
| 1121 | err = -EFAULT; |
| 1122 | |
| 1123 | return err; |
| 1124 | } |
| 1125 | |
| 1126 | static int |
| 1127 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { |
| 1128 | struct loop_info64 info64; |
| 1129 | int err = 0; |
| 1130 | |
| 1131 | if (!arg) |
| 1132 | err = -EINVAL; |
| 1133 | if (!err) |
| 1134 | err = loop_get_status(lo, &info64); |
| 1135 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) |
| 1136 | err = -EFAULT; |
| 1137 | |
| 1138 | return err; |
| 1139 | } |
| 1140 | |
| 1141 | static int lo_ioctl(struct inode * inode, struct file * file, |
| 1142 | unsigned int cmd, unsigned long arg) |
| 1143 | { |
| 1144 | struct loop_device *lo = inode->i_bdev->bd_disk->private_data; |
| 1145 | int err; |
| 1146 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1147 | mutex_lock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1148 | switch (cmd) { |
| 1149 | case LOOP_SET_FD: |
| 1150 | err = loop_set_fd(lo, file, inode->i_bdev, arg); |
| 1151 | break; |
| 1152 | case LOOP_CHANGE_FD: |
| 1153 | err = loop_change_fd(lo, file, inode->i_bdev, arg); |
| 1154 | break; |
| 1155 | case LOOP_CLR_FD: |
| 1156 | err = loop_clr_fd(lo, inode->i_bdev); |
| 1157 | break; |
| 1158 | case LOOP_SET_STATUS: |
| 1159 | err = loop_set_status_old(lo, (struct loop_info __user *) arg); |
| 1160 | break; |
| 1161 | case LOOP_GET_STATUS: |
| 1162 | err = loop_get_status_old(lo, (struct loop_info __user *) arg); |
| 1163 | break; |
| 1164 | case LOOP_SET_STATUS64: |
| 1165 | err = loop_set_status64(lo, (struct loop_info64 __user *) arg); |
| 1166 | break; |
| 1167 | case LOOP_GET_STATUS64: |
| 1168 | err = loop_get_status64(lo, (struct loop_info64 __user *) arg); |
| 1169 | break; |
| 1170 | default: |
| 1171 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; |
| 1172 | } |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1173 | mutex_unlock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1174 | return err; |
| 1175 | } |
| 1176 | |
| 1177 | static int lo_open(struct inode *inode, struct file *file) |
| 1178 | { |
| 1179 | struct loop_device *lo = inode->i_bdev->bd_disk->private_data; |
| 1180 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1181 | mutex_lock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1182 | lo->lo_refcnt++; |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1183 | mutex_unlock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | |
| 1185 | return 0; |
| 1186 | } |
| 1187 | |
| 1188 | static int lo_release(struct inode *inode, struct file *file) |
| 1189 | { |
| 1190 | struct loop_device *lo = inode->i_bdev->bd_disk->private_data; |
| 1191 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1192 | mutex_lock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1193 | --lo->lo_refcnt; |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1194 | mutex_unlock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | |
| 1196 | return 0; |
| 1197 | } |
| 1198 | |
| 1199 | static struct block_device_operations lo_fops = { |
| 1200 | .owner = THIS_MODULE, |
| 1201 | .open = lo_open, |
| 1202 | .release = lo_release, |
| 1203 | .ioctl = lo_ioctl, |
| 1204 | }; |
| 1205 | |
| 1206 | /* |
| 1207 | * And now the modules code and kernel interface. |
| 1208 | */ |
| 1209 | module_param(max_loop, int, 0); |
| 1210 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)"); |
| 1211 | MODULE_LICENSE("GPL"); |
| 1212 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); |
| 1213 | |
| 1214 | int loop_register_transfer(struct loop_func_table *funcs) |
| 1215 | { |
| 1216 | unsigned int n = funcs->number; |
| 1217 | |
| 1218 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) |
| 1219 | return -EINVAL; |
| 1220 | xfer_funcs[n] = funcs; |
| 1221 | return 0; |
| 1222 | } |
| 1223 | |
| 1224 | int loop_unregister_transfer(int number) |
| 1225 | { |
| 1226 | unsigned int n = number; |
| 1227 | struct loop_device *lo; |
| 1228 | struct loop_func_table *xfer; |
| 1229 | |
| 1230 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) |
| 1231 | return -EINVAL; |
| 1232 | |
| 1233 | xfer_funcs[n] = NULL; |
| 1234 | |
| 1235 | for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) { |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1236 | mutex_lock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1237 | |
| 1238 | if (lo->lo_encryption == xfer) |
| 1239 | loop_release_xfer(lo); |
| 1240 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1241 | mutex_unlock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1242 | } |
| 1243 | |
| 1244 | return 0; |
| 1245 | } |
| 1246 | |
| 1247 | EXPORT_SYMBOL(loop_register_transfer); |
| 1248 | EXPORT_SYMBOL(loop_unregister_transfer); |
| 1249 | |
| 1250 | static int __init loop_init(void) |
| 1251 | { |
| 1252 | int i; |
| 1253 | |
| 1254 | if (max_loop < 1 || max_loop > 256) { |
| 1255 | printk(KERN_WARNING "loop: invalid max_loop (must be between" |
| 1256 | " 1 and 256), using default (8)\n"); |
| 1257 | max_loop = 8; |
| 1258 | } |
| 1259 | |
| 1260 | if (register_blkdev(LOOP_MAJOR, "loop")) |
| 1261 | return -EIO; |
| 1262 | |
| 1263 | loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL); |
| 1264 | if (!loop_dev) |
| 1265 | goto out_mem1; |
| 1266 | memset(loop_dev, 0, max_loop * sizeof(struct loop_device)); |
| 1267 | |
| 1268 | disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL); |
| 1269 | if (!disks) |
| 1270 | goto out_mem2; |
| 1271 | |
| 1272 | for (i = 0; i < max_loop; i++) { |
| 1273 | disks[i] = alloc_disk(1); |
| 1274 | if (!disks[i]) |
| 1275 | goto out_mem3; |
| 1276 | } |
| 1277 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1278 | for (i = 0; i < max_loop; i++) { |
| 1279 | struct loop_device *lo = &loop_dev[i]; |
| 1280 | struct gendisk *disk = disks[i]; |
| 1281 | |
| 1282 | memset(lo, 0, sizeof(*lo)); |
| 1283 | lo->lo_queue = blk_alloc_queue(GFP_KERNEL); |
| 1284 | if (!lo->lo_queue) |
| 1285 | goto out_mem4; |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1286 | mutex_init(&lo->lo_ctl_mutex); |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 1287 | init_completion(&lo->lo_done); |
Ingo Molnar | 11b751a | 2006-01-09 15:59:27 -0800 | [diff] [blame] | 1288 | init_completion(&lo->lo_bh_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | lo->lo_number = i; |
| 1290 | spin_lock_init(&lo->lo_lock); |
| 1291 | disk->major = LOOP_MAJOR; |
| 1292 | disk->first_minor = i; |
| 1293 | disk->fops = &lo_fops; |
| 1294 | sprintf(disk->disk_name, "loop%d", i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1295 | disk->private_data = lo; |
| 1296 | disk->queue = lo->lo_queue; |
| 1297 | } |
| 1298 | |
| 1299 | /* We cannot fail after we call this, so another loop!*/ |
| 1300 | for (i = 0; i < max_loop; i++) |
| 1301 | add_disk(disks[i]); |
| 1302 | printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop); |
| 1303 | return 0; |
| 1304 | |
| 1305 | out_mem4: |
| 1306 | while (i--) |
Al Viro | 1312f40 | 2006-03-12 11:02:03 -0500 | [diff] [blame] | 1307 | blk_cleanup_queue(loop_dev[i].lo_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1308 | i = max_loop; |
| 1309 | out_mem3: |
| 1310 | while (i--) |
| 1311 | put_disk(disks[i]); |
| 1312 | kfree(disks); |
| 1313 | out_mem2: |
| 1314 | kfree(loop_dev); |
| 1315 | out_mem1: |
| 1316 | unregister_blkdev(LOOP_MAJOR, "loop"); |
| 1317 | printk(KERN_ERR "loop: ran out of memory\n"); |
| 1318 | return -ENOMEM; |
| 1319 | } |
| 1320 | |
| 1321 | static void loop_exit(void) |
| 1322 | { |
| 1323 | int i; |
| 1324 | |
| 1325 | for (i = 0; i < max_loop; i++) { |
| 1326 | del_gendisk(disks[i]); |
Al Viro | 1312f40 | 2006-03-12 11:02:03 -0500 | [diff] [blame] | 1327 | blk_cleanup_queue(loop_dev[i].lo_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1328 | put_disk(disks[i]); |
| 1329 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1330 | if (unregister_blkdev(LOOP_MAJOR, "loop")) |
| 1331 | printk(KERN_WARNING "loop: cannot unregister blkdev\n"); |
| 1332 | |
| 1333 | kfree(disks); |
| 1334 | kfree(loop_dev); |
| 1335 | } |
| 1336 | |
| 1337 | module_init(loop_init); |
| 1338 | module_exit(loop_exit); |
| 1339 | |
| 1340 | #ifndef MODULE |
| 1341 | static int __init max_loop_setup(char *str) |
| 1342 | { |
| 1343 | max_loop = simple_strtol(str, NULL, 0); |
| 1344 | return 1; |
| 1345 | } |
| 1346 | |
| 1347 | __setup("max_loop=", max_loop_setup); |
| 1348 | #endif |