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. |
Jan Engelhardt | 96de0e2 | 2007-10-19 23:21:04 +0200 | [diff] [blame] | 32 | * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Nick Piggin | 4e02ed4 | 2008-10-29 14:00:55 -0700 | [diff] [blame] | 43 | * operations write_begin is not available on the backing filesystem. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | #include <linux/swap.h> |
| 65 | #include <linux/slab.h> |
| 66 | #include <linux/loop.h> |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 67 | #include <linux/compat.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | #include <linux/suspend.h> |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 69 | #include <linux/freezer.h> |
Arnd Bergmann | 2a48fc0 | 2010-06-02 14:28:52 +0200 | [diff] [blame] | 70 | #include <linux/mutex.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | #include <linux/writeback.h> |
| 72 | #include <linux/buffer_head.h> /* for invalidate_bdev() */ |
| 73 | #include <linux/completion.h> |
| 74 | #include <linux/highmem.h> |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 75 | #include <linux/kthread.h> |
Jens Axboe | d6b29d7 | 2007-06-04 09:59:47 +0200 | [diff] [blame] | 76 | #include <linux/splice.h> |
Milan Broz | ee86273 | 2010-08-23 15:16:00 +0200 | [diff] [blame] | 77 | #include <linux/sysfs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
| 79 | #include <asm/uaccess.h> |
| 80 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 81 | static LIST_HEAD(loop_devices); |
| 82 | static DEFINE_MUTEX(loop_devices_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 84 | static int max_part; |
| 85 | static int part_shift; |
| 86 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | /* |
| 88 | * Transfer functions |
| 89 | */ |
| 90 | static int transfer_none(struct loop_device *lo, int cmd, |
| 91 | struct page *raw_page, unsigned raw_off, |
| 92 | struct page *loop_page, unsigned loop_off, |
| 93 | int size, sector_t real_block) |
| 94 | { |
| 95 | char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; |
| 96 | char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; |
| 97 | |
| 98 | if (cmd == READ) |
| 99 | memcpy(loop_buf, raw_buf, size); |
| 100 | else |
| 101 | memcpy(raw_buf, loop_buf, size); |
| 102 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | kunmap_atomic(loop_buf, KM_USER1); |
Peter Zijlstra | 61ecdb80 | 2010-10-26 14:21:47 -0700 | [diff] [blame] | 104 | kunmap_atomic(raw_buf, KM_USER0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 105 | cond_resched(); |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | static int transfer_xor(struct loop_device *lo, int cmd, |
| 110 | struct page *raw_page, unsigned raw_off, |
| 111 | struct page *loop_page, unsigned loop_off, |
| 112 | int size, sector_t real_block) |
| 113 | { |
| 114 | char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; |
| 115 | char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; |
| 116 | char *in, *out, *key; |
| 117 | int i, keysize; |
| 118 | |
| 119 | if (cmd == READ) { |
| 120 | in = raw_buf; |
| 121 | out = loop_buf; |
| 122 | } else { |
| 123 | in = loop_buf; |
| 124 | out = raw_buf; |
| 125 | } |
| 126 | |
| 127 | key = lo->lo_encrypt_key; |
| 128 | keysize = lo->lo_encrypt_key_size; |
| 129 | for (i = 0; i < size; i++) |
| 130 | *out++ = *in++ ^ key[(i & 511) % keysize]; |
| 131 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | kunmap_atomic(loop_buf, KM_USER1); |
Peter Zijlstra | 61ecdb80 | 2010-10-26 14:21:47 -0700 | [diff] [blame] | 133 | kunmap_atomic(raw_buf, KM_USER0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | cond_resched(); |
| 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | static int xor_init(struct loop_device *lo, const struct loop_info64 *info) |
| 139 | { |
| 140 | if (unlikely(info->lo_encrypt_key_size <= 0)) |
| 141 | return -EINVAL; |
| 142 | return 0; |
| 143 | } |
| 144 | |
| 145 | static struct loop_func_table none_funcs = { |
| 146 | .number = LO_CRYPT_NONE, |
| 147 | .transfer = transfer_none, |
| 148 | }; |
| 149 | |
| 150 | static struct loop_func_table xor_funcs = { |
| 151 | .number = LO_CRYPT_XOR, |
| 152 | .transfer = transfer_xor, |
| 153 | .init = xor_init |
| 154 | }; |
| 155 | |
| 156 | /* xfer_funcs[0] is special - its release function is never called */ |
| 157 | static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { |
| 158 | &none_funcs, |
| 159 | &xor_funcs |
| 160 | }; |
| 161 | |
| 162 | static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
| 163 | { |
| 164 | loff_t size, offset, loopsize; |
| 165 | |
| 166 | /* Compute loopsize in bytes */ |
| 167 | size = i_size_read(file->f_mapping->host); |
| 168 | offset = lo->lo_offset; |
| 169 | loopsize = size - offset; |
| 170 | if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize) |
| 171 | loopsize = lo->lo_sizelimit; |
| 172 | |
| 173 | /* |
| 174 | * Unfortunately, if we want to do I/O on the device, |
| 175 | * the number of 512-byte sectors has to fit into a sector_t. |
| 176 | */ |
| 177 | return loopsize >> 9; |
| 178 | } |
| 179 | |
| 180 | static int |
| 181 | figure_loop_size(struct loop_device *lo) |
| 182 | { |
| 183 | loff_t size = get_loop_size(lo, lo->lo_backing_file); |
| 184 | sector_t x = (sector_t)size; |
| 185 | |
| 186 | if (unlikely((loff_t)x != size)) |
| 187 | return -EFBIG; |
| 188 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 189 | set_capacity(lo->lo_disk, x); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | return 0; |
| 191 | } |
| 192 | |
| 193 | static inline int |
| 194 | lo_do_transfer(struct loop_device *lo, int cmd, |
| 195 | struct page *rpage, unsigned roffs, |
| 196 | struct page *lpage, unsigned loffs, |
| 197 | int size, sector_t rblock) |
| 198 | { |
| 199 | if (unlikely(!lo->transfer)) |
| 200 | return 0; |
| 201 | |
| 202 | return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); |
| 203 | } |
| 204 | |
| 205 | /** |
| 206 | * do_lo_send_aops - helper for writing data to a loop device |
| 207 | * |
| 208 | * This is the fast version for backing filesystems which implement the address |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 209 | * space operations write_begin and write_end. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | */ |
| 211 | static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 212 | loff_t pos, struct page *unused) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | { |
| 214 | struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */ |
| 215 | struct address_space *mapping = file->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | pgoff_t index; |
| 217 | unsigned offset, bv_offs; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 218 | int len, ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 220 | mutex_lock(&mapping->host->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | index = pos >> PAGE_CACHE_SHIFT; |
| 222 | offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1); |
| 223 | bv_offs = bvec->bv_offset; |
| 224 | len = bvec->bv_len; |
| 225 | while (len > 0) { |
| 226 | sector_t IV; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 227 | unsigned size, copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | int transfer_result; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 229 | struct page *page; |
| 230 | void *fsdata; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | |
| 232 | IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); |
| 233 | size = PAGE_CACHE_SIZE - offset; |
| 234 | if (size > len) |
| 235 | size = len; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 236 | |
| 237 | ret = pagecache_write_begin(file, mapping, pos, size, 0, |
| 238 | &page, &fsdata); |
| 239 | if (ret) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | goto fail; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 241 | |
Nikanth Karthikesan | 02246c4 | 2010-04-08 21:39:31 +0200 | [diff] [blame] | 242 | file_update_time(file); |
| 243 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | transfer_result = lo_do_transfer(lo, WRITE, page, offset, |
| 245 | bvec->bv_page, bv_offs, size, IV); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 246 | copied = size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | if (unlikely(transfer_result)) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 248 | copied = 0; |
| 249 | |
| 250 | ret = pagecache_write_end(file, mapping, pos, size, copied, |
| 251 | page, fsdata); |
Dmitry Monakhov | 8268f5a | 2007-10-16 01:25:02 -0700 | [diff] [blame] | 252 | if (ret < 0 || ret != copied) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 253 | goto fail; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 254 | |
| 255 | if (unlikely(transfer_result)) |
| 256 | goto fail; |
| 257 | |
| 258 | bv_offs += copied; |
| 259 | len -= copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | offset = 0; |
| 261 | index++; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 262 | pos += copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | } |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 264 | ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | out: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 266 | mutex_unlock(&mapping->host->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | fail: |
| 269 | ret = -1; |
| 270 | goto out; |
| 271 | } |
| 272 | |
| 273 | /** |
| 274 | * __do_lo_send_write - helper for writing data to a loop device |
| 275 | * |
| 276 | * This helper just factors out common code between do_lo_send_direct_write() |
| 277 | * and do_lo_send_write(). |
| 278 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 279 | static int __do_lo_send_write(struct file *file, |
Al Viro | 98ae6cc | 2006-10-10 22:45:07 +0100 | [diff] [blame] | 280 | u8 *buf, const int len, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | { |
| 282 | ssize_t bw; |
| 283 | mm_segment_t old_fs = get_fs(); |
| 284 | |
| 285 | set_fs(get_ds()); |
| 286 | bw = file->f_op->write(file, buf, len, &pos); |
| 287 | set_fs(old_fs); |
| 288 | if (likely(bw == len)) |
| 289 | return 0; |
| 290 | printk(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", |
| 291 | (unsigned long long)pos, len); |
| 292 | if (bw >= 0) |
| 293 | bw = -EIO; |
| 294 | return bw; |
| 295 | } |
| 296 | |
| 297 | /** |
| 298 | * do_lo_send_direct_write - helper for writing data to a loop device |
| 299 | * |
| 300 | * This is the fast, non-transforming version for backing filesystems which do |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 301 | * not implement the address space operations write_begin and write_end. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | * It uses the write file operation which should be present on all writeable |
| 303 | * filesystems. |
| 304 | */ |
| 305 | static int do_lo_send_direct_write(struct loop_device *lo, |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 306 | struct bio_vec *bvec, loff_t pos, struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | { |
| 308 | ssize_t bw = __do_lo_send_write(lo->lo_backing_file, |
Al Viro | 98ae6cc | 2006-10-10 22:45:07 +0100 | [diff] [blame] | 309 | kmap(bvec->bv_page) + bvec->bv_offset, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | bvec->bv_len, pos); |
| 311 | kunmap(bvec->bv_page); |
| 312 | cond_resched(); |
| 313 | return bw; |
| 314 | } |
| 315 | |
| 316 | /** |
| 317 | * do_lo_send_write - helper for writing data to a loop device |
| 318 | * |
| 319 | * This is the slow, transforming version for filesystems which do not |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 320 | * implement the address space operations write_begin and write_end. It |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | * uses the write file operation which should be present on all writeable |
| 322 | * filesystems. |
| 323 | * |
| 324 | * Using fops->write is slower than using aops->{prepare,commit}_write in the |
| 325 | * transforming case because we need to double buffer the data as we cannot do |
| 326 | * the transformations in place as we do not have direct access to the |
| 327 | * destination pages of the backing file. |
| 328 | */ |
| 329 | static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 330 | loff_t pos, struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | { |
| 332 | int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, |
| 333 | bvec->bv_offset, bvec->bv_len, pos >> 9); |
| 334 | if (likely(!ret)) |
| 335 | return __do_lo_send_write(lo->lo_backing_file, |
Al Viro | 98ae6cc | 2006-10-10 22:45:07 +0100 | [diff] [blame] | 336 | page_address(page), bvec->bv_len, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | pos); |
| 338 | printk(KERN_ERR "loop: Transfer error at byte offset %llu, " |
| 339 | "length %i.\n", (unsigned long long)pos, bvec->bv_len); |
| 340 | if (ret > 0) |
| 341 | ret = -EIO; |
| 342 | return ret; |
| 343 | } |
| 344 | |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 345 | static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | { |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 347 | int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | struct page *page); |
| 349 | struct bio_vec *bvec; |
| 350 | struct page *page = NULL; |
| 351 | int i, ret = 0; |
| 352 | |
| 353 | do_lo_send = do_lo_send_aops; |
| 354 | if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) { |
| 355 | do_lo_send = do_lo_send_direct_write; |
| 356 | if (lo->transfer != transfer_none) { |
| 357 | page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); |
| 358 | if (unlikely(!page)) |
| 359 | goto fail; |
| 360 | kmap(page); |
| 361 | do_lo_send = do_lo_send_write; |
| 362 | } |
| 363 | } |
| 364 | bio_for_each_segment(bvec, bio, i) { |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 365 | ret = do_lo_send(lo, bvec, pos, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 366 | if (ret < 0) |
| 367 | break; |
| 368 | pos += bvec->bv_len; |
| 369 | } |
| 370 | if (page) { |
| 371 | kunmap(page); |
| 372 | __free_page(page); |
| 373 | } |
| 374 | out: |
| 375 | return ret; |
| 376 | fail: |
| 377 | printk(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); |
| 378 | ret = -ENOMEM; |
| 379 | goto out; |
| 380 | } |
| 381 | |
| 382 | struct lo_read_data { |
| 383 | struct loop_device *lo; |
| 384 | struct page *page; |
| 385 | unsigned offset; |
| 386 | int bsize; |
| 387 | }; |
| 388 | |
| 389 | static int |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 390 | lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| 391 | struct splice_desc *sd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | { |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 393 | struct lo_read_data *p = sd->u.data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | struct loop_device *lo = p->lo; |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 395 | struct page *page = buf->page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | sector_t IV; |
Jens Axboe | 3603b8e | 2010-12-20 09:15:19 +0100 | [diff] [blame] | 397 | int size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 399 | IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) + |
| 400 | (buf->offset >> 9); |
| 401 | size = sd->len; |
| 402 | if (size > p->bsize) |
| 403 | size = p->bsize; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 405 | if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | printk(KERN_ERR "loop: transfer error block %ld\n", |
| 407 | page->index); |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 408 | size = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | } |
| 410 | |
| 411 | flush_dcache_page(p->page); |
| 412 | |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 413 | if (size > 0) |
| 414 | p->offset += size; |
| 415 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | return size; |
| 417 | } |
| 418 | |
| 419 | static int |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 420 | lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| 421 | { |
| 422 | return __splice_from_pipe(pipe, sd, lo_splice_actor); |
| 423 | } |
| 424 | |
| 425 | static int |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | do_lo_receive(struct loop_device *lo, |
| 427 | struct bio_vec *bvec, int bsize, loff_t pos) |
| 428 | { |
| 429 | struct lo_read_data cookie; |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 430 | struct splice_desc sd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | struct file *file; |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 432 | long retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | |
| 434 | cookie.lo = lo; |
| 435 | cookie.page = bvec->bv_page; |
| 436 | cookie.offset = bvec->bv_offset; |
| 437 | cookie.bsize = bsize; |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 438 | |
| 439 | sd.len = 0; |
| 440 | sd.total_len = bvec->bv_len; |
| 441 | sd.flags = 0; |
| 442 | sd.pos = pos; |
| 443 | sd.u.data = &cookie; |
| 444 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | file = lo->lo_backing_file; |
Jens Axboe | fd58214 | 2007-06-12 21:20:37 +0200 | [diff] [blame] | 446 | retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor); |
| 447 | |
| 448 | if (retval < 0) |
| 449 | return retval; |
| 450 | |
| 451 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | } |
| 453 | |
| 454 | static int |
| 455 | lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos) |
| 456 | { |
| 457 | struct bio_vec *bvec; |
| 458 | int i, ret = 0; |
| 459 | |
| 460 | bio_for_each_segment(bvec, bio, i) { |
| 461 | ret = do_lo_receive(lo, bvec, bsize, pos); |
| 462 | if (ret < 0) |
| 463 | break; |
| 464 | pos += bvec->bv_len; |
| 465 | } |
| 466 | return ret; |
| 467 | } |
| 468 | |
| 469 | static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) |
| 470 | { |
| 471 | loff_t pos; |
| 472 | int ret; |
| 473 | |
| 474 | pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 475 | |
| 476 | if (bio_rw(bio) == WRITE) { |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 477 | struct file *file = lo->lo_backing_file; |
| 478 | |
Tejun Heo | 6259f28 | 2010-09-03 11:56:17 +0200 | [diff] [blame] | 479 | if (bio->bi_rw & REQ_FLUSH) { |
Christoph Hellwig | 8018ab0 | 2010-03-22 17:32:25 +0100 | [diff] [blame] | 480 | ret = vfs_fsync(file, 0); |
Tejun Heo | 6259f28 | 2010-09-03 11:56:17 +0200 | [diff] [blame] | 481 | if (unlikely(ret && ret != -EINVAL)) { |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 482 | ret = -EIO; |
| 483 | goto out; |
| 484 | } |
| 485 | } |
| 486 | |
Al Viro | 511de73 | 2007-10-08 12:10:13 -0400 | [diff] [blame] | 487 | ret = lo_send(lo, bio, pos); |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 488 | |
Tejun Heo | 6259f28 | 2010-09-03 11:56:17 +0200 | [diff] [blame] | 489 | if ((bio->bi_rw & REQ_FUA) && !ret) { |
Christoph Hellwig | 8018ab0 | 2010-03-22 17:32:25 +0100 | [diff] [blame] | 490 | ret = vfs_fsync(file, 0); |
Tejun Heo | 6259f28 | 2010-09-03 11:56:17 +0200 | [diff] [blame] | 491 | if (unlikely(ret && ret != -EINVAL)) |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 492 | ret = -EIO; |
| 493 | } |
| 494 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | ret = lo_receive(lo, bio, lo->lo_blocksize, pos); |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 496 | |
| 497 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | return ret; |
| 499 | } |
| 500 | |
| 501 | /* |
| 502 | * Add bio to back of pending list |
| 503 | */ |
| 504 | static void loop_add_bio(struct loop_device *lo, struct bio *bio) |
| 505 | { |
Akinobu Mita | e686307 | 2009-04-17 08:41:21 +0200 | [diff] [blame] | 506 | bio_list_add(&lo->lo_bio_list, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | } |
| 508 | |
| 509 | /* |
| 510 | * Grab first pending buffer |
| 511 | */ |
| 512 | static struct bio *loop_get_bio(struct loop_device *lo) |
| 513 | { |
Akinobu Mita | e686307 | 2009-04-17 08:41:21 +0200 | [diff] [blame] | 514 | return bio_list_pop(&lo->lo_bio_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | } |
| 516 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 517 | static int loop_make_request(struct request_queue *q, struct bio *old_bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | { |
| 519 | struct loop_device *lo = q->queuedata; |
| 520 | int rw = bio_rw(old_bio); |
| 521 | |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 522 | if (rw == READA) |
| 523 | rw = READ; |
| 524 | |
| 525 | BUG_ON(!lo || (rw != READ && rw != WRITE)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | |
| 527 | spin_lock_irq(&lo->lo_lock); |
| 528 | if (lo->lo_state != Lo_bound) |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 529 | goto out; |
| 530 | if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY))) |
| 531 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 532 | loop_add_bio(lo, old_bio); |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 533 | wake_up(&lo->lo_event); |
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 | return 0; |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 536 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | out: |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 538 | spin_unlock_irq(&lo->lo_lock); |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 539 | bio_io_error(old_bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | } |
| 542 | |
| 543 | /* |
| 544 | * kick off io on the underlying address space |
| 545 | */ |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 546 | static void loop_unplug(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | { |
| 548 | struct loop_device *lo = q->queuedata; |
| 549 | |
Nick Piggin | 75ad23b | 2008-04-29 14:48:33 +0200 | [diff] [blame] | 550 | queue_flag_clear_unlocked(QUEUE_FLAG_PLUGGED, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 551 | blk_run_address_space(lo->lo_backing_file->f_mapping); |
| 552 | } |
| 553 | |
| 554 | struct switch_request { |
| 555 | struct file *file; |
| 556 | struct completion wait; |
| 557 | }; |
| 558 | |
| 559 | static void do_loop_switch(struct loop_device *, struct switch_request *); |
| 560 | |
| 561 | static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) |
| 562 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | if (unlikely(!bio->bi_bdev)) { |
| 564 | do_loop_switch(lo, bio->bi_private); |
| 565 | bio_put(bio); |
| 566 | } else { |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 567 | int ret = do_bio_filebacked(lo, bio); |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 568 | bio_endio(bio, ret); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | } |
| 570 | } |
| 571 | |
| 572 | /* |
| 573 | * worker thread that handles reads/writes to file backed loop devices, |
| 574 | * to avoid blocking in our make_request_fn. it also does loop decrypting |
| 575 | * on reads for block backed loop, as that is too heavy to do from |
| 576 | * b_end_io context where irqs may be disabled. |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 577 | * |
| 578 | * Loop explanation: loop_clr_fd() sets lo_state to Lo_rundown before |
| 579 | * calling kthread_stop(). Therefore once kthread_should_stop() is |
| 580 | * true, make_request will not place any more requests. Therefore |
| 581 | * once kthread_should_stop() is true and lo_bio is NULL, we are |
| 582 | * done with the loop. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 583 | */ |
| 584 | static int loop_thread(void *data) |
| 585 | { |
| 586 | struct loop_device *lo = data; |
| 587 | struct bio *bio; |
| 588 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | set_user_nice(current, -20); |
| 590 | |
Akinobu Mita | e686307 | 2009-04-17 08:41:21 +0200 | [diff] [blame] | 591 | while (!kthread_should_stop() || !bio_list_empty(&lo->lo_bio_list)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 593 | wait_event_interruptible(lo->lo_event, |
Akinobu Mita | e686307 | 2009-04-17 08:41:21 +0200 | [diff] [blame] | 594 | !bio_list_empty(&lo->lo_bio_list) || |
| 595 | kthread_should_stop()); |
Linus Torvalds | 09c0dc6 | 2006-06-26 11:55:42 -0700 | [diff] [blame] | 596 | |
Akinobu Mita | e686307 | 2009-04-17 08:41:21 +0200 | [diff] [blame] | 597 | if (bio_list_empty(&lo->lo_bio_list)) |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 598 | continue; |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 599 | spin_lock_irq(&lo->lo_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | bio = loop_get_bio(lo); |
Nick Piggin | 35a82d1 | 2005-06-23 00:09:06 -0700 | [diff] [blame] | 601 | spin_unlock_irq(&lo->lo_lock); |
| 602 | |
| 603 | BUG_ON(!bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | loop_handle_bio(lo, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | } |
| 606 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | return 0; |
| 608 | } |
| 609 | |
| 610 | /* |
| 611 | * loop_switch performs the hard work of switching a backing store. |
| 612 | * First it needs to flush existing IO, it does this by sending a magic |
| 613 | * BIO down the pipe. The completion of this BIO does the actual switch. |
| 614 | */ |
| 615 | static int loop_switch(struct loop_device *lo, struct file *file) |
| 616 | { |
| 617 | struct switch_request w; |
Jens Axboe | a24eab1 | 2008-01-11 10:14:40 +0100 | [diff] [blame] | 618 | struct bio *bio = bio_alloc(GFP_KERNEL, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | if (!bio) |
| 620 | return -ENOMEM; |
| 621 | init_completion(&w.wait); |
| 622 | w.file = file; |
| 623 | bio->bi_private = &w; |
| 624 | bio->bi_bdev = NULL; |
| 625 | loop_make_request(lo->lo_queue, bio); |
| 626 | wait_for_completion(&w.wait); |
| 627 | return 0; |
| 628 | } |
| 629 | |
| 630 | /* |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 631 | * Helper to flush the IOs in loop, but keeping loop thread running |
| 632 | */ |
| 633 | static int loop_flush(struct loop_device *lo) |
| 634 | { |
| 635 | /* loop not yet configured, no running thread, nothing to flush */ |
| 636 | if (!lo->lo_thread) |
| 637 | return 0; |
| 638 | |
| 639 | return loop_switch(lo, NULL); |
| 640 | } |
| 641 | |
| 642 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | * Do the actual switch; called from the BIO completion routine |
| 644 | */ |
| 645 | static void do_loop_switch(struct loop_device *lo, struct switch_request *p) |
| 646 | { |
| 647 | struct file *file = p->file; |
| 648 | struct file *old_file = lo->lo_backing_file; |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 649 | struct address_space *mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 651 | /* if no new file, only flush of queued bios requested */ |
| 652 | if (!file) |
| 653 | goto out; |
| 654 | |
| 655 | mapping = file->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); |
| 657 | lo->lo_backing_file = file; |
Theodore Ts'o | ba52de1 | 2006-09-27 01:50:49 -0700 | [diff] [blame] | 658 | lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ? |
| 659 | mapping->host->i_bdev->bd_block_size : PAGE_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
| 661 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 662 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | complete(&p->wait); |
| 664 | } |
| 665 | |
| 666 | |
| 667 | /* |
| 668 | * loop_change_fd switched the backing store of a loopback device to |
| 669 | * a new file. This is useful for operating system installers to free up |
| 670 | * the original file and in High Availability environments to switch to |
| 671 | * an alternative location for the content in case of server meltdown. |
| 672 | * This can only work if the loop device is used read-only, and if the |
| 673 | * new backing store is the same size and type as the old backing store. |
| 674 | */ |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 675 | static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
| 676 | unsigned int arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | { |
| 678 | struct file *file, *old_file; |
| 679 | struct inode *inode; |
| 680 | int error; |
| 681 | |
| 682 | error = -ENXIO; |
| 683 | if (lo->lo_state != Lo_bound) |
| 684 | goto out; |
| 685 | |
| 686 | /* the loop device has to be read-only */ |
| 687 | error = -EINVAL; |
| 688 | if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) |
| 689 | goto out; |
| 690 | |
| 691 | error = -EBADF; |
| 692 | file = fget(arg); |
| 693 | if (!file) |
| 694 | goto out; |
| 695 | |
| 696 | inode = file->f_mapping->host; |
| 697 | old_file = lo->lo_backing_file; |
| 698 | |
| 699 | error = -EINVAL; |
| 700 | |
| 701 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
| 702 | goto out_putf; |
| 703 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | /* size of the new backing store needs to be the same */ |
| 705 | if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) |
| 706 | goto out_putf; |
| 707 | |
| 708 | /* and ... switch */ |
| 709 | error = loop_switch(lo, file); |
| 710 | if (error) |
| 711 | goto out_putf; |
| 712 | |
| 713 | fput(old_file); |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 714 | if (max_part > 0) |
| 715 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 716 | return 0; |
| 717 | |
| 718 | out_putf: |
| 719 | fput(file); |
| 720 | out: |
| 721 | return error; |
| 722 | } |
| 723 | |
| 724 | static inline int is_loop_device(struct file *file) |
| 725 | { |
| 726 | struct inode *i = file->f_mapping->host; |
| 727 | |
| 728 | return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; |
| 729 | } |
| 730 | |
Milan Broz | ee86273 | 2010-08-23 15:16:00 +0200 | [diff] [blame] | 731 | /* loop sysfs attributes */ |
| 732 | |
| 733 | static ssize_t loop_attr_show(struct device *dev, char *page, |
| 734 | ssize_t (*callback)(struct loop_device *, char *)) |
| 735 | { |
| 736 | struct loop_device *l, *lo = NULL; |
| 737 | |
| 738 | mutex_lock(&loop_devices_mutex); |
| 739 | list_for_each_entry(l, &loop_devices, lo_list) |
| 740 | if (disk_to_dev(l->lo_disk) == dev) { |
| 741 | lo = l; |
| 742 | break; |
| 743 | } |
| 744 | mutex_unlock(&loop_devices_mutex); |
| 745 | |
| 746 | return lo ? callback(lo, page) : -EIO; |
| 747 | } |
| 748 | |
| 749 | #define LOOP_ATTR_RO(_name) \ |
| 750 | static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ |
| 751 | static ssize_t loop_attr_do_show_##_name(struct device *d, \ |
| 752 | struct device_attribute *attr, char *b) \ |
| 753 | { \ |
| 754 | return loop_attr_show(d, b, loop_attr_##_name##_show); \ |
| 755 | } \ |
| 756 | static struct device_attribute loop_attr_##_name = \ |
| 757 | __ATTR(_name, S_IRUGO, loop_attr_do_show_##_name, NULL); |
| 758 | |
| 759 | static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) |
| 760 | { |
| 761 | ssize_t ret; |
| 762 | char *p = NULL; |
| 763 | |
| 764 | mutex_lock(&lo->lo_ctl_mutex); |
| 765 | if (lo->lo_backing_file) |
| 766 | p = d_path(&lo->lo_backing_file->f_path, buf, PAGE_SIZE - 1); |
| 767 | mutex_unlock(&lo->lo_ctl_mutex); |
| 768 | |
| 769 | if (IS_ERR_OR_NULL(p)) |
| 770 | ret = PTR_ERR(p); |
| 771 | else { |
| 772 | ret = strlen(p); |
| 773 | memmove(buf, p, ret); |
| 774 | buf[ret++] = '\n'; |
| 775 | buf[ret] = 0; |
| 776 | } |
| 777 | |
| 778 | return ret; |
| 779 | } |
| 780 | |
| 781 | static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) |
| 782 | { |
| 783 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); |
| 784 | } |
| 785 | |
| 786 | static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) |
| 787 | { |
| 788 | return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); |
| 789 | } |
| 790 | |
| 791 | static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) |
| 792 | { |
| 793 | int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); |
| 794 | |
| 795 | return sprintf(buf, "%s\n", autoclear ? "1" : "0"); |
| 796 | } |
| 797 | |
| 798 | LOOP_ATTR_RO(backing_file); |
| 799 | LOOP_ATTR_RO(offset); |
| 800 | LOOP_ATTR_RO(sizelimit); |
| 801 | LOOP_ATTR_RO(autoclear); |
| 802 | |
| 803 | static struct attribute *loop_attrs[] = { |
| 804 | &loop_attr_backing_file.attr, |
| 805 | &loop_attr_offset.attr, |
| 806 | &loop_attr_sizelimit.attr, |
| 807 | &loop_attr_autoclear.attr, |
| 808 | NULL, |
| 809 | }; |
| 810 | |
| 811 | static struct attribute_group loop_attribute_group = { |
| 812 | .name = "loop", |
| 813 | .attrs= loop_attrs, |
| 814 | }; |
| 815 | |
| 816 | static int loop_sysfs_init(struct loop_device *lo) |
| 817 | { |
| 818 | return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, |
| 819 | &loop_attribute_group); |
| 820 | } |
| 821 | |
| 822 | static void loop_sysfs_exit(struct loop_device *lo) |
| 823 | { |
| 824 | sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, |
| 825 | &loop_attribute_group); |
| 826 | } |
| 827 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 828 | static int loop_set_fd(struct loop_device *lo, fmode_t mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | struct block_device *bdev, unsigned int arg) |
| 830 | { |
| 831 | struct file *file, *f; |
| 832 | struct inode *inode; |
| 833 | struct address_space *mapping; |
| 834 | unsigned lo_blocksize; |
| 835 | int lo_flags = 0; |
| 836 | int error; |
| 837 | loff_t size; |
| 838 | |
| 839 | /* This is safe, since we have a reference from open(). */ |
| 840 | __module_get(THIS_MODULE); |
| 841 | |
| 842 | error = -EBADF; |
| 843 | file = fget(arg); |
| 844 | if (!file) |
| 845 | goto out; |
| 846 | |
| 847 | error = -EBUSY; |
| 848 | if (lo->lo_state != Lo_unbound) |
| 849 | goto out_putf; |
| 850 | |
| 851 | /* Avoid recursion */ |
| 852 | f = file; |
| 853 | while (is_loop_device(f)) { |
| 854 | struct loop_device *l; |
| 855 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 856 | if (f->f_mapping->host->i_bdev == bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | goto out_putf; |
| 858 | |
| 859 | l = f->f_mapping->host->i_bdev->bd_disk->private_data; |
| 860 | if (l->lo_state == Lo_unbound) { |
| 861 | error = -EINVAL; |
| 862 | goto out_putf; |
| 863 | } |
| 864 | f = l->lo_backing_file; |
| 865 | } |
| 866 | |
| 867 | mapping = file->f_mapping; |
| 868 | inode = mapping->host; |
| 869 | |
| 870 | if (!(file->f_mode & FMODE_WRITE)) |
| 871 | lo_flags |= LO_FLAGS_READ_ONLY; |
| 872 | |
| 873 | error = -EINVAL; |
| 874 | if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) { |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 875 | const struct address_space_operations *aops = mapping->a_ops; |
Miklos Szeredi | 6818173 | 2009-05-07 15:37:36 +0200 | [diff] [blame] | 876 | |
Nick Piggin | 4e02ed4 | 2008-10-29 14:00:55 -0700 | [diff] [blame] | 877 | if (aops->write_begin) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 878 | lo_flags |= LO_FLAGS_USE_AOPS; |
| 879 | if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write) |
| 880 | lo_flags |= LO_FLAGS_READ_ONLY; |
| 881 | |
Theodore Ts'o | ba52de1 | 2006-09-27 01:50:49 -0700 | [diff] [blame] | 882 | lo_blocksize = S_ISBLK(inode->i_mode) ? |
| 883 | inode->i_bdev->bd_block_size : PAGE_SIZE; |
| 884 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 885 | error = 0; |
| 886 | } else { |
| 887 | goto out_putf; |
| 888 | } |
| 889 | |
| 890 | size = get_loop_size(lo, file); |
| 891 | |
| 892 | if ((loff_t)(sector_t)size != size) { |
| 893 | error = -EFBIG; |
| 894 | goto out_putf; |
| 895 | } |
| 896 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 897 | if (!(mode & FMODE_WRITE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | lo_flags |= LO_FLAGS_READ_ONLY; |
| 899 | |
| 900 | set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); |
| 901 | |
| 902 | lo->lo_blocksize = lo_blocksize; |
| 903 | lo->lo_device = bdev; |
| 904 | lo->lo_flags = lo_flags; |
| 905 | lo->lo_backing_file = file; |
Constantine Sapuntzakis | eefe85e | 2006-06-23 02:06:08 -0700 | [diff] [blame] | 906 | lo->transfer = transfer_none; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | lo->ioctl = NULL; |
| 908 | lo->lo_sizelimit = 0; |
| 909 | lo->old_gfp_mask = mapping_gfp_mask(mapping); |
| 910 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
| 911 | |
Akinobu Mita | e686307 | 2009-04-17 08:41:21 +0200 | [diff] [blame] | 912 | bio_list_init(&lo->lo_bio_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 913 | |
| 914 | /* |
| 915 | * set queue make_request_fn, and add limits based on lower level |
| 916 | * device |
| 917 | */ |
| 918 | blk_queue_make_request(lo->lo_queue, loop_make_request); |
| 919 | lo->lo_queue->queuedata = lo; |
| 920 | lo->lo_queue->unplug_fn = loop_unplug; |
| 921 | |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 922 | if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
Tejun Heo | 4913efe | 2010-09-03 11:56:16 +0200 | [diff] [blame] | 923 | blk_queue_flush(lo->lo_queue, REQ_FLUSH); |
Nikanth Karthikesan | 68db196 | 2009-03-24 12:29:54 +0100 | [diff] [blame] | 924 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 925 | set_capacity(lo->lo_disk, size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 926 | bd_set_size(bdev, size << 9); |
Milan Broz | ee86273 | 2010-08-23 15:16:00 +0200 | [diff] [blame] | 927 | loop_sysfs_init(lo); |
David Zeuthen | c3473c6 | 2010-05-03 14:08:59 +0200 | [diff] [blame] | 928 | /* let user-space know about the new size */ |
| 929 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 930 | |
| 931 | set_blocksize(bdev, lo_blocksize); |
| 932 | |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 933 | lo->lo_thread = kthread_create(loop_thread, lo, "loop%d", |
| 934 | lo->lo_number); |
| 935 | if (IS_ERR(lo->lo_thread)) { |
| 936 | error = PTR_ERR(lo->lo_thread); |
Serge E. Hallyn | a7422bf | 2006-09-29 02:01:18 -0700 | [diff] [blame] | 937 | goto out_clr; |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 938 | } |
| 939 | lo->lo_state = Lo_bound; |
| 940 | wake_up_process(lo->lo_thread); |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 941 | if (max_part > 0) |
| 942 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | return 0; |
| 944 | |
Serge E. Hallyn | a7422bf | 2006-09-29 02:01:18 -0700 | [diff] [blame] | 945 | out_clr: |
Milan Broz | ee86273 | 2010-08-23 15:16:00 +0200 | [diff] [blame] | 946 | loop_sysfs_exit(lo); |
Serge E. Hallyn | a7422bf | 2006-09-29 02:01:18 -0700 | [diff] [blame] | 947 | lo->lo_thread = NULL; |
| 948 | lo->lo_device = NULL; |
| 949 | lo->lo_backing_file = NULL; |
| 950 | lo->lo_flags = 0; |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 951 | set_capacity(lo->lo_disk, 0); |
Peter Zijlstra | f98393a | 2007-05-06 14:49:54 -0700 | [diff] [blame] | 952 | invalidate_bdev(bdev); |
Serge E. Hallyn | a7422bf | 2006-09-29 02:01:18 -0700 | [diff] [blame] | 953 | bd_set_size(bdev, 0); |
David Zeuthen | c3473c6 | 2010-05-03 14:08:59 +0200 | [diff] [blame] | 954 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); |
Serge E. Hallyn | a7422bf | 2006-09-29 02:01:18 -0700 | [diff] [blame] | 955 | mapping_set_gfp_mask(mapping, lo->old_gfp_mask); |
| 956 | lo->lo_state = Lo_unbound; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | out_putf: |
| 958 | fput(file); |
| 959 | out: |
| 960 | /* This is safe: open() is still holding a reference. */ |
| 961 | module_put(THIS_MODULE); |
| 962 | return error; |
| 963 | } |
| 964 | |
| 965 | static int |
| 966 | loop_release_xfer(struct loop_device *lo) |
| 967 | { |
| 968 | int err = 0; |
| 969 | struct loop_func_table *xfer = lo->lo_encryption; |
| 970 | |
| 971 | if (xfer) { |
| 972 | if (xfer->release) |
| 973 | err = xfer->release(lo); |
| 974 | lo->transfer = NULL; |
| 975 | lo->lo_encryption = NULL; |
| 976 | module_put(xfer->owner); |
| 977 | } |
| 978 | return err; |
| 979 | } |
| 980 | |
| 981 | static int |
| 982 | loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, |
| 983 | const struct loop_info64 *i) |
| 984 | { |
| 985 | int err = 0; |
| 986 | |
| 987 | if (xfer) { |
| 988 | struct module *owner = xfer->owner; |
| 989 | |
| 990 | if (!try_module_get(owner)) |
| 991 | return -EINVAL; |
| 992 | if (xfer->init) |
| 993 | err = xfer->init(lo, i); |
| 994 | if (err) |
| 995 | module_put(owner); |
| 996 | else |
| 997 | lo->lo_encryption = xfer; |
| 998 | } |
| 999 | return err; |
| 1000 | } |
| 1001 | |
| 1002 | static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) |
| 1003 | { |
| 1004 | struct file *filp = lo->lo_backing_file; |
Al Viro | b4e3ca1 | 2005-10-21 03:22:34 -0400 | [diff] [blame] | 1005 | gfp_t gfp = lo->old_gfp_mask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1006 | |
| 1007 | if (lo->lo_state != Lo_bound) |
| 1008 | return -ENXIO; |
| 1009 | |
| 1010 | if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */ |
| 1011 | return -EBUSY; |
| 1012 | |
| 1013 | if (filp == NULL) |
| 1014 | return -EINVAL; |
| 1015 | |
| 1016 | spin_lock_irq(&lo->lo_lock); |
| 1017 | lo->lo_state = Lo_rundown; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1018 | spin_unlock_irq(&lo->lo_lock); |
| 1019 | |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 1020 | kthread_stop(lo->lo_thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1021 | |
Milan Broz | 8ae30b8 | 2008-12-12 14:50:49 +0100 | [diff] [blame] | 1022 | lo->lo_queue->unplug_fn = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1023 | lo->lo_backing_file = NULL; |
| 1024 | |
| 1025 | loop_release_xfer(lo); |
| 1026 | lo->transfer = NULL; |
| 1027 | lo->ioctl = NULL; |
| 1028 | lo->lo_device = NULL; |
| 1029 | lo->lo_encryption = NULL; |
| 1030 | lo->lo_offset = 0; |
| 1031 | lo->lo_sizelimit = 0; |
| 1032 | lo->lo_encrypt_key_size = 0; |
| 1033 | lo->lo_flags = 0; |
Serge E. Hallyn | 6c99791 | 2006-09-29 01:59:11 -0700 | [diff] [blame] | 1034 | lo->lo_thread = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); |
| 1036 | memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); |
| 1037 | memset(lo->lo_file_name, 0, LO_NAME_SIZE); |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1038 | if (bdev) |
| 1039 | invalidate_bdev(bdev); |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1040 | set_capacity(lo->lo_disk, 0); |
Milan Broz | 51a0bb0 | 2010-10-27 19:51:30 -0600 | [diff] [blame] | 1041 | loop_sysfs_exit(lo); |
David Zeuthen | c3473c6 | 2010-05-03 14:08:59 +0200 | [diff] [blame] | 1042 | if (bdev) { |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1043 | bd_set_size(bdev, 0); |
David Zeuthen | c3473c6 | 2010-05-03 14:08:59 +0200 | [diff] [blame] | 1044 | /* let user-space know about this change */ |
| 1045 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); |
| 1046 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | mapping_set_gfp_mask(filp->f_mapping, gfp); |
| 1048 | lo->lo_state = Lo_unbound; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1049 | /* This is safe: open() is still holding a reference. */ |
| 1050 | module_put(THIS_MODULE); |
Alexey Dobriyan | cf6e693 | 2009-10-26 16:49:55 -0700 | [diff] [blame] | 1051 | if (max_part > 0 && bdev) |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1052 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
Nikanth Karthikesan | f028f3b | 2009-03-24 12:33:41 +0100 | [diff] [blame] | 1053 | mutex_unlock(&lo->lo_ctl_mutex); |
| 1054 | /* |
| 1055 | * Need not hold lo_ctl_mutex to fput backing file. |
| 1056 | * Calling fput holding lo_ctl_mutex triggers a circular |
| 1057 | * lock dependency possibility warning as fput can take |
| 1058 | * bd_mutex which is usually taken before lo_ctl_mutex. |
| 1059 | */ |
| 1060 | fput(filp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | return 0; |
| 1062 | } |
| 1063 | |
| 1064 | static int |
| 1065 | loop_set_status(struct loop_device *lo, const struct loop_info64 *info) |
| 1066 | { |
| 1067 | int err; |
| 1068 | struct loop_func_table *xfer; |
David Howells | b0fafa8 | 2008-11-14 10:38:41 +1100 | [diff] [blame] | 1069 | uid_t uid = current_uid(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | |
David Howells | b0fafa8 | 2008-11-14 10:38:41 +1100 | [diff] [blame] | 1071 | if (lo->lo_encrypt_key_size && |
| 1072 | lo->lo_key_owner != uid && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1073 | !capable(CAP_SYS_ADMIN)) |
| 1074 | return -EPERM; |
| 1075 | if (lo->lo_state != Lo_bound) |
| 1076 | return -ENXIO; |
| 1077 | if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) |
| 1078 | return -EINVAL; |
| 1079 | |
| 1080 | err = loop_release_xfer(lo); |
| 1081 | if (err) |
| 1082 | return err; |
| 1083 | |
| 1084 | if (info->lo_encrypt_type) { |
| 1085 | unsigned int type = info->lo_encrypt_type; |
| 1086 | |
| 1087 | if (type >= MAX_LO_CRYPT) |
| 1088 | return -EINVAL; |
| 1089 | xfer = xfer_funcs[type]; |
| 1090 | if (xfer == NULL) |
| 1091 | return -EINVAL; |
| 1092 | } else |
| 1093 | xfer = NULL; |
| 1094 | |
| 1095 | err = loop_init_xfer(lo, xfer, info); |
| 1096 | if (err) |
| 1097 | return err; |
| 1098 | |
| 1099 | if (lo->lo_offset != info->lo_offset || |
| 1100 | lo->lo_sizelimit != info->lo_sizelimit) { |
| 1101 | lo->lo_offset = info->lo_offset; |
| 1102 | lo->lo_sizelimit = info->lo_sizelimit; |
| 1103 | if (figure_loop_size(lo)) |
| 1104 | return -EFBIG; |
| 1105 | } |
| 1106 | |
| 1107 | memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); |
| 1108 | memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); |
| 1109 | lo->lo_file_name[LO_NAME_SIZE-1] = 0; |
| 1110 | lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; |
| 1111 | |
| 1112 | if (!xfer) |
| 1113 | xfer = &none_funcs; |
| 1114 | lo->transfer = xfer->transfer; |
| 1115 | lo->ioctl = xfer->ioctl; |
| 1116 | |
David Woodhouse | 96c5865 | 2008-02-06 01:36:27 -0800 | [diff] [blame] | 1117 | if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != |
| 1118 | (info->lo_flags & LO_FLAGS_AUTOCLEAR)) |
| 1119 | lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; |
| 1120 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | lo->lo_encrypt_key_size = info->lo_encrypt_key_size; |
| 1122 | lo->lo_init[0] = info->lo_init[0]; |
| 1123 | lo->lo_init[1] = info->lo_init[1]; |
| 1124 | if (info->lo_encrypt_key_size) { |
| 1125 | memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, |
| 1126 | info->lo_encrypt_key_size); |
David Howells | b0fafa8 | 2008-11-14 10:38:41 +1100 | [diff] [blame] | 1127 | lo->lo_key_owner = uid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | } |
| 1129 | |
| 1130 | return 0; |
| 1131 | } |
| 1132 | |
| 1133 | static int |
| 1134 | loop_get_status(struct loop_device *lo, struct loop_info64 *info) |
| 1135 | { |
| 1136 | struct file *file = lo->lo_backing_file; |
| 1137 | struct kstat stat; |
| 1138 | int error; |
| 1139 | |
| 1140 | if (lo->lo_state != Lo_bound) |
| 1141 | return -ENXIO; |
Josef Sipek | 6c648be | 2006-12-08 02:36:55 -0800 | [diff] [blame] | 1142 | error = vfs_getattr(file->f_path.mnt, file->f_path.dentry, &stat); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1143 | if (error) |
| 1144 | return error; |
| 1145 | memset(info, 0, sizeof(*info)); |
| 1146 | info->lo_number = lo->lo_number; |
| 1147 | info->lo_device = huge_encode_dev(stat.dev); |
| 1148 | info->lo_inode = stat.ino; |
| 1149 | info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev); |
| 1150 | info->lo_offset = lo->lo_offset; |
| 1151 | info->lo_sizelimit = lo->lo_sizelimit; |
| 1152 | info->lo_flags = lo->lo_flags; |
| 1153 | memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); |
| 1154 | memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); |
| 1155 | info->lo_encrypt_type = |
| 1156 | lo->lo_encryption ? lo->lo_encryption->number : 0; |
| 1157 | if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { |
| 1158 | info->lo_encrypt_key_size = lo->lo_encrypt_key_size; |
| 1159 | memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, |
| 1160 | lo->lo_encrypt_key_size); |
| 1161 | } |
| 1162 | return 0; |
| 1163 | } |
| 1164 | |
| 1165 | static void |
| 1166 | loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) |
| 1167 | { |
| 1168 | memset(info64, 0, sizeof(*info64)); |
| 1169 | info64->lo_number = info->lo_number; |
| 1170 | info64->lo_device = info->lo_device; |
| 1171 | info64->lo_inode = info->lo_inode; |
| 1172 | info64->lo_rdevice = info->lo_rdevice; |
| 1173 | info64->lo_offset = info->lo_offset; |
| 1174 | info64->lo_sizelimit = 0; |
| 1175 | info64->lo_encrypt_type = info->lo_encrypt_type; |
| 1176 | info64->lo_encrypt_key_size = info->lo_encrypt_key_size; |
| 1177 | info64->lo_flags = info->lo_flags; |
| 1178 | info64->lo_init[0] = info->lo_init[0]; |
| 1179 | info64->lo_init[1] = info->lo_init[1]; |
| 1180 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) |
| 1181 | memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); |
| 1182 | else |
| 1183 | memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); |
| 1184 | memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); |
| 1185 | } |
| 1186 | |
| 1187 | static int |
| 1188 | loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) |
| 1189 | { |
| 1190 | memset(info, 0, sizeof(*info)); |
| 1191 | info->lo_number = info64->lo_number; |
| 1192 | info->lo_device = info64->lo_device; |
| 1193 | info->lo_inode = info64->lo_inode; |
| 1194 | info->lo_rdevice = info64->lo_rdevice; |
| 1195 | info->lo_offset = info64->lo_offset; |
| 1196 | info->lo_encrypt_type = info64->lo_encrypt_type; |
| 1197 | info->lo_encrypt_key_size = info64->lo_encrypt_key_size; |
| 1198 | info->lo_flags = info64->lo_flags; |
| 1199 | info->lo_init[0] = info64->lo_init[0]; |
| 1200 | info->lo_init[1] = info64->lo_init[1]; |
| 1201 | if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) |
| 1202 | memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); |
| 1203 | else |
| 1204 | memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); |
| 1205 | memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); |
| 1206 | |
| 1207 | /* error in case values were truncated */ |
| 1208 | if (info->lo_device != info64->lo_device || |
| 1209 | info->lo_rdevice != info64->lo_rdevice || |
| 1210 | info->lo_inode != info64->lo_inode || |
| 1211 | info->lo_offset != info64->lo_offset) |
| 1212 | return -EOVERFLOW; |
| 1213 | |
| 1214 | return 0; |
| 1215 | } |
| 1216 | |
| 1217 | static int |
| 1218 | loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) |
| 1219 | { |
| 1220 | struct loop_info info; |
| 1221 | struct loop_info64 info64; |
| 1222 | |
| 1223 | if (copy_from_user(&info, arg, sizeof (struct loop_info))) |
| 1224 | return -EFAULT; |
| 1225 | loop_info64_from_old(&info, &info64); |
| 1226 | return loop_set_status(lo, &info64); |
| 1227 | } |
| 1228 | |
| 1229 | static int |
| 1230 | loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) |
| 1231 | { |
| 1232 | struct loop_info64 info64; |
| 1233 | |
| 1234 | if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) |
| 1235 | return -EFAULT; |
| 1236 | return loop_set_status(lo, &info64); |
| 1237 | } |
| 1238 | |
| 1239 | static int |
| 1240 | loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { |
| 1241 | struct loop_info info; |
| 1242 | struct loop_info64 info64; |
| 1243 | int err = 0; |
| 1244 | |
| 1245 | if (!arg) |
| 1246 | err = -EINVAL; |
| 1247 | if (!err) |
| 1248 | err = loop_get_status(lo, &info64); |
| 1249 | if (!err) |
| 1250 | err = loop_info64_to_old(&info64, &info); |
| 1251 | if (!err && copy_to_user(arg, &info, sizeof(info))) |
| 1252 | err = -EFAULT; |
| 1253 | |
| 1254 | return err; |
| 1255 | } |
| 1256 | |
| 1257 | static int |
| 1258 | loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { |
| 1259 | struct loop_info64 info64; |
| 1260 | int err = 0; |
| 1261 | |
| 1262 | if (!arg) |
| 1263 | err = -EINVAL; |
| 1264 | if (!err) |
| 1265 | err = loop_get_status(lo, &info64); |
| 1266 | if (!err && copy_to_user(arg, &info64, sizeof(info64))) |
| 1267 | err = -EFAULT; |
| 1268 | |
| 1269 | return err; |
| 1270 | } |
| 1271 | |
J. R. Okajima | 53d6660 | 2009-03-31 15:23:43 -0700 | [diff] [blame] | 1272 | static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) |
| 1273 | { |
| 1274 | int err; |
| 1275 | sector_t sec; |
| 1276 | loff_t sz; |
| 1277 | |
| 1278 | err = -ENXIO; |
| 1279 | if (unlikely(lo->lo_state != Lo_bound)) |
| 1280 | goto out; |
| 1281 | err = figure_loop_size(lo); |
| 1282 | if (unlikely(err)) |
| 1283 | goto out; |
| 1284 | sec = get_capacity(lo->lo_disk); |
| 1285 | /* the width of sector_t may be narrow for bit-shift */ |
| 1286 | sz = sec; |
| 1287 | sz <<= 9; |
| 1288 | mutex_lock(&bdev->bd_mutex); |
| 1289 | bd_set_size(bdev, sz); |
David Zeuthen | c3473c6 | 2010-05-03 14:08:59 +0200 | [diff] [blame] | 1290 | /* let user-space know about the new size */ |
| 1291 | kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); |
J. R. Okajima | 53d6660 | 2009-03-31 15:23:43 -0700 | [diff] [blame] | 1292 | mutex_unlock(&bdev->bd_mutex); |
| 1293 | |
| 1294 | out: |
| 1295 | return err; |
| 1296 | } |
| 1297 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1298 | static int lo_ioctl(struct block_device *bdev, fmode_t mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | unsigned int cmd, unsigned long arg) |
| 1300 | { |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1301 | struct loop_device *lo = bdev->bd_disk->private_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1302 | int err; |
| 1303 | |
Nikanth Karthikesan | f028f3b | 2009-03-24 12:33:41 +0100 | [diff] [blame] | 1304 | mutex_lock_nested(&lo->lo_ctl_mutex, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1305 | switch (cmd) { |
| 1306 | case LOOP_SET_FD: |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1307 | err = loop_set_fd(lo, mode, bdev, arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1308 | break; |
| 1309 | case LOOP_CHANGE_FD: |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1310 | err = loop_change_fd(lo, bdev, arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1311 | break; |
| 1312 | case LOOP_CLR_FD: |
Nikanth Karthikesan | f028f3b | 2009-03-24 12:33:41 +0100 | [diff] [blame] | 1313 | /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1314 | err = loop_clr_fd(lo, bdev); |
Nikanth Karthikesan | f028f3b | 2009-03-24 12:33:41 +0100 | [diff] [blame] | 1315 | if (!err) |
| 1316 | goto out_unlocked; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1317 | break; |
| 1318 | case LOOP_SET_STATUS: |
| 1319 | err = loop_set_status_old(lo, (struct loop_info __user *) arg); |
| 1320 | break; |
| 1321 | case LOOP_GET_STATUS: |
| 1322 | err = loop_get_status_old(lo, (struct loop_info __user *) arg); |
| 1323 | break; |
| 1324 | case LOOP_SET_STATUS64: |
| 1325 | err = loop_set_status64(lo, (struct loop_info64 __user *) arg); |
| 1326 | break; |
| 1327 | case LOOP_GET_STATUS64: |
| 1328 | err = loop_get_status64(lo, (struct loop_info64 __user *) arg); |
| 1329 | break; |
J. R. Okajima | 53d6660 | 2009-03-31 15:23:43 -0700 | [diff] [blame] | 1330 | case LOOP_SET_CAPACITY: |
| 1331 | err = -EPERM; |
| 1332 | if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) |
| 1333 | err = loop_set_capacity(lo, bdev); |
| 1334 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1335 | default: |
| 1336 | err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; |
| 1337 | } |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1338 | mutex_unlock(&lo->lo_ctl_mutex); |
Nikanth Karthikesan | f028f3b | 2009-03-24 12:33:41 +0100 | [diff] [blame] | 1339 | |
| 1340 | out_unlocked: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | return err; |
| 1342 | } |
| 1343 | |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1344 | #ifdef CONFIG_COMPAT |
| 1345 | struct compat_loop_info { |
| 1346 | compat_int_t lo_number; /* ioctl r/o */ |
| 1347 | compat_dev_t lo_device; /* ioctl r/o */ |
| 1348 | compat_ulong_t lo_inode; /* ioctl r/o */ |
| 1349 | compat_dev_t lo_rdevice; /* ioctl r/o */ |
| 1350 | compat_int_t lo_offset; |
| 1351 | compat_int_t lo_encrypt_type; |
| 1352 | compat_int_t lo_encrypt_key_size; /* ioctl w/o */ |
| 1353 | compat_int_t lo_flags; /* ioctl r/o */ |
| 1354 | char lo_name[LO_NAME_SIZE]; |
| 1355 | unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ |
| 1356 | compat_ulong_t lo_init[2]; |
| 1357 | char reserved[4]; |
| 1358 | }; |
| 1359 | |
| 1360 | /* |
| 1361 | * Transfer 32-bit compatibility structure in userspace to 64-bit loop info |
| 1362 | * - noinlined to reduce stack space usage in main part of driver |
| 1363 | */ |
| 1364 | static noinline int |
Al Viro | ba674cf | 2006-10-10 22:48:27 +0100 | [diff] [blame] | 1365 | loop_info64_from_compat(const struct compat_loop_info __user *arg, |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1366 | struct loop_info64 *info64) |
| 1367 | { |
| 1368 | struct compat_loop_info info; |
| 1369 | |
| 1370 | if (copy_from_user(&info, arg, sizeof(info))) |
| 1371 | return -EFAULT; |
| 1372 | |
| 1373 | memset(info64, 0, sizeof(*info64)); |
| 1374 | info64->lo_number = info.lo_number; |
| 1375 | info64->lo_device = info.lo_device; |
| 1376 | info64->lo_inode = info.lo_inode; |
| 1377 | info64->lo_rdevice = info.lo_rdevice; |
| 1378 | info64->lo_offset = info.lo_offset; |
| 1379 | info64->lo_sizelimit = 0; |
| 1380 | info64->lo_encrypt_type = info.lo_encrypt_type; |
| 1381 | info64->lo_encrypt_key_size = info.lo_encrypt_key_size; |
| 1382 | info64->lo_flags = info.lo_flags; |
| 1383 | info64->lo_init[0] = info.lo_init[0]; |
| 1384 | info64->lo_init[1] = info.lo_init[1]; |
| 1385 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) |
| 1386 | memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); |
| 1387 | else |
| 1388 | memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); |
| 1389 | memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); |
| 1390 | return 0; |
| 1391 | } |
| 1392 | |
| 1393 | /* |
| 1394 | * Transfer 64-bit loop info to 32-bit compatibility structure in userspace |
| 1395 | * - noinlined to reduce stack space usage in main part of driver |
| 1396 | */ |
| 1397 | static noinline int |
| 1398 | loop_info64_to_compat(const struct loop_info64 *info64, |
| 1399 | struct compat_loop_info __user *arg) |
| 1400 | { |
| 1401 | struct compat_loop_info info; |
| 1402 | |
| 1403 | memset(&info, 0, sizeof(info)); |
| 1404 | info.lo_number = info64->lo_number; |
| 1405 | info.lo_device = info64->lo_device; |
| 1406 | info.lo_inode = info64->lo_inode; |
| 1407 | info.lo_rdevice = info64->lo_rdevice; |
| 1408 | info.lo_offset = info64->lo_offset; |
| 1409 | info.lo_encrypt_type = info64->lo_encrypt_type; |
| 1410 | info.lo_encrypt_key_size = info64->lo_encrypt_key_size; |
| 1411 | info.lo_flags = info64->lo_flags; |
| 1412 | info.lo_init[0] = info64->lo_init[0]; |
| 1413 | info.lo_init[1] = info64->lo_init[1]; |
| 1414 | if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) |
| 1415 | memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); |
| 1416 | else |
| 1417 | memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); |
| 1418 | memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); |
| 1419 | |
| 1420 | /* error in case values were truncated */ |
| 1421 | if (info.lo_device != info64->lo_device || |
| 1422 | info.lo_rdevice != info64->lo_rdevice || |
| 1423 | info.lo_inode != info64->lo_inode || |
| 1424 | info.lo_offset != info64->lo_offset || |
| 1425 | info.lo_init[0] != info64->lo_init[0] || |
| 1426 | info.lo_init[1] != info64->lo_init[1]) |
| 1427 | return -EOVERFLOW; |
| 1428 | |
| 1429 | if (copy_to_user(arg, &info, sizeof(info))) |
| 1430 | return -EFAULT; |
| 1431 | return 0; |
| 1432 | } |
| 1433 | |
| 1434 | static int |
| 1435 | loop_set_status_compat(struct loop_device *lo, |
| 1436 | const struct compat_loop_info __user *arg) |
| 1437 | { |
| 1438 | struct loop_info64 info64; |
| 1439 | int ret; |
| 1440 | |
| 1441 | ret = loop_info64_from_compat(arg, &info64); |
| 1442 | if (ret < 0) |
| 1443 | return ret; |
| 1444 | return loop_set_status(lo, &info64); |
| 1445 | } |
| 1446 | |
| 1447 | static int |
| 1448 | loop_get_status_compat(struct loop_device *lo, |
| 1449 | struct compat_loop_info __user *arg) |
| 1450 | { |
| 1451 | struct loop_info64 info64; |
| 1452 | int err = 0; |
| 1453 | |
| 1454 | if (!arg) |
| 1455 | err = -EINVAL; |
| 1456 | if (!err) |
| 1457 | err = loop_get_status(lo, &info64); |
| 1458 | if (!err) |
| 1459 | err = loop_info64_to_compat(&info64, arg); |
| 1460 | return err; |
| 1461 | } |
| 1462 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1463 | static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
| 1464 | unsigned int cmd, unsigned long arg) |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1465 | { |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1466 | struct loop_device *lo = bdev->bd_disk->private_data; |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1467 | int err; |
| 1468 | |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1469 | switch(cmd) { |
| 1470 | case LOOP_SET_STATUS: |
| 1471 | mutex_lock(&lo->lo_ctl_mutex); |
| 1472 | err = loop_set_status_compat( |
| 1473 | lo, (const struct compat_loop_info __user *) arg); |
| 1474 | mutex_unlock(&lo->lo_ctl_mutex); |
| 1475 | break; |
| 1476 | case LOOP_GET_STATUS: |
| 1477 | mutex_lock(&lo->lo_ctl_mutex); |
| 1478 | err = loop_get_status_compat( |
| 1479 | lo, (struct compat_loop_info __user *) arg); |
| 1480 | mutex_unlock(&lo->lo_ctl_mutex); |
| 1481 | break; |
J. R. Okajima | 53d6660 | 2009-03-31 15:23:43 -0700 | [diff] [blame] | 1482 | case LOOP_SET_CAPACITY: |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1483 | case LOOP_CLR_FD: |
| 1484 | case LOOP_GET_STATUS64: |
| 1485 | case LOOP_SET_STATUS64: |
| 1486 | arg = (unsigned long) compat_ptr(arg); |
| 1487 | case LOOP_SET_FD: |
| 1488 | case LOOP_CHANGE_FD: |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1489 | err = lo_ioctl(bdev, mode, cmd, arg); |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1490 | break; |
| 1491 | default: |
| 1492 | err = -ENOIOCTLCMD; |
| 1493 | break; |
| 1494 | } |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1495 | return err; |
| 1496 | } |
| 1497 | #endif |
| 1498 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1499 | static int lo_open(struct block_device *bdev, fmode_t mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1500 | { |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1501 | struct loop_device *lo = bdev->bd_disk->private_data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1502 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1503 | mutex_lock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1504 | lo->lo_refcnt++; |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1505 | mutex_unlock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1506 | |
| 1507 | return 0; |
| 1508 | } |
| 1509 | |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1510 | static int lo_release(struct gendisk *disk, fmode_t mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1511 | { |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1512 | struct loop_device *lo = disk->private_data; |
Alexander Beregalov | ffcd7dc | 2009-04-07 13:48:21 +0200 | [diff] [blame] | 1513 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1514 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1515 | mutex_lock(&lo->lo_ctl_mutex); |
David Woodhouse | 96c5865 | 2008-02-06 01:36:27 -0800 | [diff] [blame] | 1516 | |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 1517 | if (--lo->lo_refcnt) |
| 1518 | goto out; |
| 1519 | |
| 1520 | if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { |
| 1521 | /* |
| 1522 | * In autoclear mode, stop the loop thread |
| 1523 | * and remove configuration after last close. |
| 1524 | */ |
Alexander Beregalov | ffcd7dc | 2009-04-07 13:48:21 +0200 | [diff] [blame] | 1525 | err = loop_clr_fd(lo, NULL); |
| 1526 | if (!err) |
| 1527 | goto out_unlocked; |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 1528 | } else { |
| 1529 | /* |
| 1530 | * Otherwise keep thread (if running) and config, |
| 1531 | * but flush possible ongoing bios in thread. |
| 1532 | */ |
| 1533 | loop_flush(lo); |
| 1534 | } |
David Woodhouse | 96c5865 | 2008-02-06 01:36:27 -0800 | [diff] [blame] | 1535 | |
Milan Broz | 14f2793 | 2008-12-12 14:48:27 +0100 | [diff] [blame] | 1536 | out: |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1537 | mutex_unlock(&lo->lo_ctl_mutex); |
Alexander Beregalov | ffcd7dc | 2009-04-07 13:48:21 +0200 | [diff] [blame] | 1538 | out_unlocked: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1539 | return 0; |
| 1540 | } |
| 1541 | |
Alexey Dobriyan | 83d5cde | 2009-09-21 17:01:13 -0700 | [diff] [blame] | 1542 | static const struct block_device_operations lo_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1543 | .owner = THIS_MODULE, |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1544 | .open = lo_open, |
| 1545 | .release = lo_release, |
| 1546 | .ioctl = lo_ioctl, |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1547 | #ifdef CONFIG_COMPAT |
Al Viro | bb21488 | 2008-03-02 09:29:48 -0500 | [diff] [blame] | 1548 | .compat_ioctl = lo_compat_ioctl, |
David Howells | 863d5b8 | 2006-08-29 19:06:14 +0100 | [diff] [blame] | 1549 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1550 | }; |
| 1551 | |
| 1552 | /* |
| 1553 | * And now the modules code and kernel interface. |
| 1554 | */ |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1555 | static int max_loop; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1556 | module_param(max_loop, int, 0); |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1557 | MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1558 | module_param(max_part, int, 0); |
| 1559 | MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1560 | MODULE_LICENSE("GPL"); |
| 1561 | MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); |
| 1562 | |
| 1563 | int loop_register_transfer(struct loop_func_table *funcs) |
| 1564 | { |
| 1565 | unsigned int n = funcs->number; |
| 1566 | |
| 1567 | if (n >= MAX_LO_CRYPT || xfer_funcs[n]) |
| 1568 | return -EINVAL; |
| 1569 | xfer_funcs[n] = funcs; |
| 1570 | return 0; |
| 1571 | } |
| 1572 | |
| 1573 | int loop_unregister_transfer(int number) |
| 1574 | { |
| 1575 | unsigned int n = number; |
| 1576 | struct loop_device *lo; |
| 1577 | struct loop_func_table *xfer; |
| 1578 | |
| 1579 | if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) |
| 1580 | return -EINVAL; |
| 1581 | |
| 1582 | xfer_funcs[n] = NULL; |
| 1583 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1584 | list_for_each_entry(lo, &loop_devices, lo_list) { |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1585 | mutex_lock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1586 | |
| 1587 | if (lo->lo_encryption == xfer) |
| 1588 | loop_release_xfer(lo); |
| 1589 | |
Ingo Molnar | f85221d | 2006-03-23 03:00:38 -0800 | [diff] [blame] | 1590 | mutex_unlock(&lo->lo_ctl_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1591 | } |
| 1592 | |
| 1593 | return 0; |
| 1594 | } |
| 1595 | |
| 1596 | EXPORT_SYMBOL(loop_register_transfer); |
| 1597 | EXPORT_SYMBOL(loop_unregister_transfer); |
| 1598 | |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1599 | static struct loop_device *loop_alloc(int i) |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1600 | { |
| 1601 | struct loop_device *lo; |
| 1602 | struct gendisk *disk; |
| 1603 | |
| 1604 | lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
| 1605 | if (!lo) |
| 1606 | goto out; |
| 1607 | |
| 1608 | lo->lo_queue = blk_alloc_queue(GFP_KERNEL); |
| 1609 | if (!lo->lo_queue) |
| 1610 | goto out_free_dev; |
| 1611 | |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1612 | disk = lo->lo_disk = alloc_disk(1 << part_shift); |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1613 | if (!disk) |
| 1614 | goto out_free_queue; |
| 1615 | |
| 1616 | mutex_init(&lo->lo_ctl_mutex); |
| 1617 | lo->lo_number = i; |
| 1618 | lo->lo_thread = NULL; |
| 1619 | init_waitqueue_head(&lo->lo_event); |
| 1620 | spin_lock_init(&lo->lo_lock); |
| 1621 | disk->major = LOOP_MAJOR; |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1622 | disk->first_minor = i << part_shift; |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1623 | disk->fops = &lo_fops; |
| 1624 | disk->private_data = lo; |
| 1625 | disk->queue = lo->lo_queue; |
| 1626 | sprintf(disk->disk_name, "loop%d", i); |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1627 | return lo; |
| 1628 | |
| 1629 | out_free_queue: |
| 1630 | blk_cleanup_queue(lo->lo_queue); |
| 1631 | out_free_dev: |
| 1632 | kfree(lo); |
| 1633 | out: |
Al Viro | 07002e9 | 2007-05-12 16:23:15 -0400 | [diff] [blame] | 1634 | return NULL; |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1635 | } |
| 1636 | |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1637 | static void loop_free(struct loop_device *lo) |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1638 | { |
Sergey Senozhatsky | ee71a96 | 2011-01-19 08:25:02 -0700 | [diff] [blame] | 1639 | if (!lo->lo_queue->queue_lock) |
| 1640 | lo->lo_queue->queue_lock = &lo->lo_queue->__queue_lock; |
| 1641 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1642 | blk_cleanup_queue(lo->lo_queue); |
| 1643 | put_disk(lo->lo_disk); |
| 1644 | list_del(&lo->lo_list); |
| 1645 | kfree(lo); |
| 1646 | } |
| 1647 | |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1648 | static struct loop_device *loop_init_one(int i) |
| 1649 | { |
| 1650 | struct loop_device *lo; |
| 1651 | |
| 1652 | list_for_each_entry(lo, &loop_devices, lo_list) { |
| 1653 | if (lo->lo_number == i) |
| 1654 | return lo; |
| 1655 | } |
| 1656 | |
| 1657 | lo = loop_alloc(i); |
| 1658 | if (lo) { |
| 1659 | add_disk(lo->lo_disk); |
| 1660 | list_add_tail(&lo->lo_list, &loop_devices); |
| 1661 | } |
| 1662 | return lo; |
| 1663 | } |
| 1664 | |
| 1665 | static void loop_del_one(struct loop_device *lo) |
| 1666 | { |
| 1667 | del_gendisk(lo->lo_disk); |
| 1668 | loop_free(lo); |
| 1669 | } |
| 1670 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1671 | static struct kobject *loop_probe(dev_t dev, int *part, void *data) |
| 1672 | { |
Al Viro | 705962c | 2007-05-13 05:52:32 -0400 | [diff] [blame] | 1673 | struct loop_device *lo; |
Al Viro | 07002e9 | 2007-05-12 16:23:15 -0400 | [diff] [blame] | 1674 | struct kobject *kobj; |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1675 | |
Al Viro | 705962c | 2007-05-13 05:52:32 -0400 | [diff] [blame] | 1676 | mutex_lock(&loop_devices_mutex); |
| 1677 | lo = loop_init_one(dev & MINORMASK); |
Al Viro | 07002e9 | 2007-05-12 16:23:15 -0400 | [diff] [blame] | 1678 | kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM); |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1679 | mutex_unlock(&loop_devices_mutex); |
| 1680 | |
| 1681 | *part = 0; |
Al Viro | 07002e9 | 2007-05-12 16:23:15 -0400 | [diff] [blame] | 1682 | return kobj; |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1683 | } |
| 1684 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1685 | static int __init loop_init(void) |
| 1686 | { |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1687 | int i, nr; |
| 1688 | unsigned long range; |
| 1689 | struct loop_device *lo, *next; |
| 1690 | |
| 1691 | /* |
| 1692 | * loop module now has a feature to instantiate underlying device |
| 1693 | * structure on-demand, provided that there is an access dev node. |
| 1694 | * However, this will not work well with user space tool that doesn't |
| 1695 | * know about such "feature". In order to not break any existing |
| 1696 | * tool, we do the following: |
| 1697 | * |
| 1698 | * (1) if max_loop is specified, create that many upfront, and this |
| 1699 | * also becomes a hard limit. |
| 1700 | * (2) if max_loop is not specified, create 8 loop device on module |
| 1701 | * load, user can further extend loop device by create dev node |
| 1702 | * themselves and have kernel automatically instantiate actual |
| 1703 | * device on-demand. |
| 1704 | */ |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1705 | |
| 1706 | part_shift = 0; |
| 1707 | if (max_part > 0) |
| 1708 | part_shift = fls(max_part); |
| 1709 | |
| 1710 | if (max_loop > 1UL << (MINORBITS - part_shift)) |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1711 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1712 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1713 | if (max_loop) { |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1714 | nr = max_loop; |
| 1715 | range = max_loop; |
| 1716 | } else { |
| 1717 | nr = 8; |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1718 | range = 1UL << (MINORBITS - part_shift); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1719 | } |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1720 | |
| 1721 | if (register_blkdev(LOOP_MAJOR, "loop")) |
| 1722 | return -EIO; |
| 1723 | |
| 1724 | for (i = 0; i < nr; i++) { |
| 1725 | lo = loop_alloc(i); |
| 1726 | if (!lo) |
| 1727 | goto Enomem; |
| 1728 | list_add_tail(&lo->lo_list, &loop_devices); |
| 1729 | } |
| 1730 | |
| 1731 | /* point of no return */ |
| 1732 | |
| 1733 | list_for_each_entry(lo, &loop_devices, lo_list) |
| 1734 | add_disk(lo->lo_disk); |
| 1735 | |
| 1736 | blk_register_region(MKDEV(LOOP_MAJOR, 0), range, |
| 1737 | THIS_MODULE, loop_probe, NULL, NULL); |
| 1738 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1739 | printk(KERN_INFO "loop: module loaded\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1740 | return 0; |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1741 | |
| 1742 | Enomem: |
| 1743 | printk(KERN_INFO "loop: out of memory\n"); |
| 1744 | |
| 1745 | list_for_each_entry_safe(lo, next, &loop_devices, lo_list) |
| 1746 | loop_free(lo); |
| 1747 | |
| 1748 | unregister_blkdev(LOOP_MAJOR, "loop"); |
| 1749 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1750 | } |
| 1751 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1752 | static void __exit loop_exit(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1753 | { |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1754 | unsigned long range; |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1755 | struct loop_device *lo, *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1756 | |
Laurent Vivier | 476a481 | 2008-03-26 12:11:53 +0100 | [diff] [blame] | 1757 | range = max_loop ? max_loop : 1UL << (MINORBITS - part_shift); |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1758 | |
Ken Chen | 7328508 | 2007-05-08 00:28:20 -0700 | [diff] [blame] | 1759 | list_for_each_entry_safe(lo, next, &loop_devices, lo_list) |
| 1760 | loop_del_one(lo); |
| 1761 | |
Ken Chen | a47653f | 2007-06-08 13:46:44 -0700 | [diff] [blame] | 1762 | blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); |
Akinobu Mita | 00d5940 | 2007-07-17 04:03:46 -0700 | [diff] [blame] | 1763 | unregister_blkdev(LOOP_MAJOR, "loop"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1764 | } |
| 1765 | |
| 1766 | module_init(loop_init); |
| 1767 | module_exit(loop_exit); |
| 1768 | |
| 1769 | #ifndef MODULE |
| 1770 | static int __init max_loop_setup(char *str) |
| 1771 | { |
| 1772 | max_loop = simple_strtol(str, NULL, 0); |
| 1773 | return 1; |
| 1774 | } |
| 1775 | |
| 1776 | __setup("max_loop=", max_loop_setup); |
| 1777 | #endif |