11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/drivers/block/loop.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Written by Theodore Ts'o, 3/29/93 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Copyright 1993 by Theodore Ts'o. Redistribution of this file is 71da177e4SLinus Torvalds * permitted under the GNU General Public License. 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993 101da177e4SLinus Torvalds * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996 111da177e4SLinus Torvalds * 121da177e4SLinus Torvalds * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994 131da177e4SLinus Torvalds * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996 141da177e4SLinus Torvalds * 151da177e4SLinus Torvalds * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997 161da177e4SLinus Torvalds * 171da177e4SLinus Torvalds * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998 181da177e4SLinus Torvalds * 191da177e4SLinus Torvalds * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998 201da177e4SLinus Torvalds * 211da177e4SLinus Torvalds * Loadable modules and other fixes by AK, 1998 221da177e4SLinus Torvalds * 231da177e4SLinus Torvalds * Make real block number available to downstream transfer functions, enables 241da177e4SLinus Torvalds * CBC (and relatives) mode encryption requiring unique IVs per data block. 251da177e4SLinus Torvalds * Reed H. Petty, rhp@draper.net 261da177e4SLinus Torvalds * 271da177e4SLinus Torvalds * Maximum number of loop devices now dynamic via max_loop module parameter. 281da177e4SLinus Torvalds * Russell Kroll <rkroll@exploits.org> 19990701 291da177e4SLinus Torvalds * 301da177e4SLinus Torvalds * Maximum number of loop devices when compiled-in now selectable by passing 311da177e4SLinus Torvalds * max_loop=<1-255> to the kernel on boot. 3296de0e25SJan Engelhardt * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999 331da177e4SLinus Torvalds * 341da177e4SLinus Torvalds * Completely rewrite request handling to be make_request_fn style and 351da177e4SLinus Torvalds * non blocking, pushing work to a helper thread. Lots of fixes from 361da177e4SLinus Torvalds * Al Viro too. 371da177e4SLinus Torvalds * Jens Axboe <axboe@suse.de>, Nov 2000 381da177e4SLinus Torvalds * 391da177e4SLinus Torvalds * Support up to 256 loop devices 401da177e4SLinus Torvalds * Heinz Mauelshagen <mge@sistina.com>, Feb 2002 411da177e4SLinus Torvalds * 421da177e4SLinus Torvalds * Support for falling back on the write file operation when the address space 434e02ed4bSNick Piggin * operations write_begin is not available on the backing filesystem. 441da177e4SLinus Torvalds * Anton Altaparmakov, 16 Feb 2005 451da177e4SLinus Torvalds * 461da177e4SLinus Torvalds * Still To Fix: 471da177e4SLinus Torvalds * - Advisory locking is ignored here. 481da177e4SLinus Torvalds * - Should use an own CAP_* category instead of CAP_SYS_ADMIN 491da177e4SLinus Torvalds * 501da177e4SLinus Torvalds */ 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds #include <linux/module.h> 531da177e4SLinus Torvalds #include <linux/moduleparam.h> 541da177e4SLinus Torvalds #include <linux/sched.h> 551da177e4SLinus Torvalds #include <linux/fs.h> 561da177e4SLinus Torvalds #include <linux/file.h> 571da177e4SLinus Torvalds #include <linux/stat.h> 581da177e4SLinus Torvalds #include <linux/errno.h> 591da177e4SLinus Torvalds #include <linux/major.h> 601da177e4SLinus Torvalds #include <linux/wait.h> 611da177e4SLinus Torvalds #include <linux/blkdev.h> 621da177e4SLinus Torvalds #include <linux/blkpg.h> 631da177e4SLinus Torvalds #include <linux/init.h> 641da177e4SLinus Torvalds #include <linux/swap.h> 651da177e4SLinus Torvalds #include <linux/slab.h> 66863d5b82SDavid Howells #include <linux/compat.h> 671da177e4SLinus Torvalds #include <linux/suspend.h> 6883144186SRafael J. Wysocki #include <linux/freezer.h> 692a48fc0aSArnd Bergmann #include <linux/mutex.h> 701da177e4SLinus Torvalds #include <linux/writeback.h> 711da177e4SLinus Torvalds #include <linux/completion.h> 721da177e4SLinus Torvalds #include <linux/highmem.h> 736c997918SSerge E. Hallyn #include <linux/kthread.h> 74d6b29d7cSJens Axboe #include <linux/splice.h> 75ee862730SMilan Broz #include <linux/sysfs.h> 76770fe30aSKay Sievers #include <linux/miscdevice.h> 77dfaa2ef6SLukas Czerner #include <linux/falloc.h> 78283e7e5dSAl Viro #include <linux/uio.h> 79d9a08a9eSAdam Manzanares #include <linux/ioprio.h> 80db6638d7SDennis Zhou #include <linux/blk-cgroup.h> 81d9a08a9eSAdam Manzanares 8283a87611SAl Viro #include "loop.h" 831da177e4SLinus Torvalds 847c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 851da177e4SLinus Torvalds 8634dd82afSKay Sievers static DEFINE_IDR(loop_index_idr); 87310ca162STetsuo Handa static DEFINE_MUTEX(loop_ctl_mutex); 881da177e4SLinus Torvalds 89476a4813SLaurent Vivier static int max_part; 90476a4813SLaurent Vivier static int part_shift; 91476a4813SLaurent Vivier 921da177e4SLinus Torvalds static int transfer_xor(struct loop_device *lo, int cmd, 931da177e4SLinus Torvalds struct page *raw_page, unsigned raw_off, 941da177e4SLinus Torvalds struct page *loop_page, unsigned loop_off, 951da177e4SLinus Torvalds int size, sector_t real_block) 961da177e4SLinus Torvalds { 97cfd8005cSCong Wang char *raw_buf = kmap_atomic(raw_page) + raw_off; 98cfd8005cSCong Wang char *loop_buf = kmap_atomic(loop_page) + loop_off; 991da177e4SLinus Torvalds char *in, *out, *key; 1001da177e4SLinus Torvalds int i, keysize; 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds if (cmd == READ) { 1031da177e4SLinus Torvalds in = raw_buf; 1041da177e4SLinus Torvalds out = loop_buf; 1051da177e4SLinus Torvalds } else { 1061da177e4SLinus Torvalds in = loop_buf; 1071da177e4SLinus Torvalds out = raw_buf; 1081da177e4SLinus Torvalds } 1091da177e4SLinus Torvalds 1101da177e4SLinus Torvalds key = lo->lo_encrypt_key; 1111da177e4SLinus Torvalds keysize = lo->lo_encrypt_key_size; 1121da177e4SLinus Torvalds for (i = 0; i < size; i++) 1131da177e4SLinus Torvalds *out++ = *in++ ^ key[(i & 511) % keysize]; 1141da177e4SLinus Torvalds 115cfd8005cSCong Wang kunmap_atomic(loop_buf); 116cfd8005cSCong Wang kunmap_atomic(raw_buf); 1171da177e4SLinus Torvalds cond_resched(); 1181da177e4SLinus Torvalds return 0; 1191da177e4SLinus Torvalds } 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds static int xor_init(struct loop_device *lo, const struct loop_info64 *info) 1221da177e4SLinus Torvalds { 1231da177e4SLinus Torvalds if (unlikely(info->lo_encrypt_key_size <= 0)) 1241da177e4SLinus Torvalds return -EINVAL; 1251da177e4SLinus Torvalds return 0; 1261da177e4SLinus Torvalds } 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds static struct loop_func_table none_funcs = { 1291da177e4SLinus Torvalds .number = LO_CRYPT_NONE, 1301da177e4SLinus Torvalds }; 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds static struct loop_func_table xor_funcs = { 1331da177e4SLinus Torvalds .number = LO_CRYPT_XOR, 1341da177e4SLinus Torvalds .transfer = transfer_xor, 1351da177e4SLinus Torvalds .init = xor_init 1361da177e4SLinus Torvalds }; 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds /* xfer_funcs[0] is special - its release function is never called */ 1391da177e4SLinus Torvalds static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { 1401da177e4SLinus Torvalds &none_funcs, 1411da177e4SLinus Torvalds &xor_funcs 1421da177e4SLinus Torvalds }; 1431da177e4SLinus Torvalds 1447035b5dfSDmitry Monakhov static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) 1451da177e4SLinus Torvalds { 146b7a1da69SGuo Chao loff_t loopsize; 1471da177e4SLinus Torvalds 1481da177e4SLinus Torvalds /* Compute loopsize in bytes */ 149b7a1da69SGuo Chao loopsize = i_size_read(file->f_mapping->host); 150b7a1da69SGuo Chao if (offset > 0) 151b7a1da69SGuo Chao loopsize -= offset; 152b7a1da69SGuo Chao /* offset is beyond i_size, weird but possible */ 1537035b5dfSDmitry Monakhov if (loopsize < 0) 1547035b5dfSDmitry Monakhov return 0; 1551da177e4SLinus Torvalds 1567035b5dfSDmitry Monakhov if (sizelimit > 0 && sizelimit < loopsize) 1577035b5dfSDmitry Monakhov loopsize = sizelimit; 1581da177e4SLinus Torvalds /* 1591da177e4SLinus Torvalds * Unfortunately, if we want to do I/O on the device, 1601da177e4SLinus Torvalds * the number of 512-byte sectors has to fit into a sector_t. 1611da177e4SLinus Torvalds */ 1621da177e4SLinus Torvalds return loopsize >> 9; 1631da177e4SLinus Torvalds } 1641da177e4SLinus Torvalds 1657035b5dfSDmitry Monakhov static loff_t get_loop_size(struct loop_device *lo, struct file *file) 1661da177e4SLinus Torvalds { 1677035b5dfSDmitry Monakhov return get_size(lo->lo_offset, lo->lo_sizelimit, file); 1687035b5dfSDmitry Monakhov } 1697035b5dfSDmitry Monakhov 1702e5ab5f3SMing Lei static void __loop_update_dio(struct loop_device *lo, bool dio) 1712e5ab5f3SMing Lei { 1722e5ab5f3SMing Lei struct file *file = lo->lo_backing_file; 1732e5ab5f3SMing Lei struct address_space *mapping = file->f_mapping; 1742e5ab5f3SMing Lei struct inode *inode = mapping->host; 1752e5ab5f3SMing Lei unsigned short sb_bsize = 0; 1762e5ab5f3SMing Lei unsigned dio_align = 0; 1772e5ab5f3SMing Lei bool use_dio; 1782e5ab5f3SMing Lei 1792e5ab5f3SMing Lei if (inode->i_sb->s_bdev) { 1802e5ab5f3SMing Lei sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev); 1812e5ab5f3SMing Lei dio_align = sb_bsize - 1; 1822e5ab5f3SMing Lei } 1832e5ab5f3SMing Lei 1842e5ab5f3SMing Lei /* 1852e5ab5f3SMing Lei * We support direct I/O only if lo_offset is aligned with the 1862e5ab5f3SMing Lei * logical I/O size of backing device, and the logical block 1872e5ab5f3SMing Lei * size of loop is bigger than the backing device's and the loop 1882e5ab5f3SMing Lei * needn't transform transfer. 1892e5ab5f3SMing Lei * 1902e5ab5f3SMing Lei * TODO: the above condition may be loosed in the future, and 1912e5ab5f3SMing Lei * direct I/O may be switched runtime at that time because most 19289d790abSMasahiro Yamada * of requests in sane applications should be PAGE_SIZE aligned 1932e5ab5f3SMing Lei */ 1942e5ab5f3SMing Lei if (dio) { 1952e5ab5f3SMing Lei if (queue_logical_block_size(lo->lo_queue) >= sb_bsize && 1962e5ab5f3SMing Lei !(lo->lo_offset & dio_align) && 1972e5ab5f3SMing Lei mapping->a_ops->direct_IO && 1982e5ab5f3SMing Lei !lo->transfer) 1992e5ab5f3SMing Lei use_dio = true; 2002e5ab5f3SMing Lei else 2012e5ab5f3SMing Lei use_dio = false; 2022e5ab5f3SMing Lei } else { 2032e5ab5f3SMing Lei use_dio = false; 2042e5ab5f3SMing Lei } 2052e5ab5f3SMing Lei 2062e5ab5f3SMing Lei if (lo->use_dio == use_dio) 2072e5ab5f3SMing Lei return; 2082e5ab5f3SMing Lei 2092e5ab5f3SMing Lei /* flush dirty pages before changing direct IO */ 2102e5ab5f3SMing Lei vfs_fsync(file, 0); 2112e5ab5f3SMing Lei 2122e5ab5f3SMing Lei /* 2132e5ab5f3SMing Lei * The flag of LO_FLAGS_DIRECT_IO is handled similarly with 2142e5ab5f3SMing Lei * LO_FLAGS_READ_ONLY, both are set from kernel, and losetup 2152e5ab5f3SMing Lei * will get updated by ioctl(LOOP_GET_STATUS) 2162e5ab5f3SMing Lei */ 2170fbcf579SMartijn Coenen if (lo->lo_state == Lo_bound) 2182e5ab5f3SMing Lei blk_mq_freeze_queue(lo->lo_queue); 2192e5ab5f3SMing Lei lo->use_dio = use_dio; 22040326d8aSShaohua Li if (use_dio) { 2218b904b5bSBart Van Assche blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue); 2222e5ab5f3SMing Lei lo->lo_flags |= LO_FLAGS_DIRECT_IO; 22340326d8aSShaohua Li } else { 2248b904b5bSBart Van Assche blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); 2252e5ab5f3SMing Lei lo->lo_flags &= ~LO_FLAGS_DIRECT_IO; 22640326d8aSShaohua Li } 2270fbcf579SMartijn Coenen if (lo->lo_state == Lo_bound) 2282e5ab5f3SMing Lei blk_mq_unfreeze_queue(lo->lo_queue); 2292e5ab5f3SMing Lei } 2302e5ab5f3SMing Lei 2317035b5dfSDmitry Monakhov static int 2321e6ec9eaSOmar Sandoval figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) 2337035b5dfSDmitry Monakhov { 2347035b5dfSDmitry Monakhov loff_t size = get_size(offset, sizelimit, lo->lo_backing_file); 2351da177e4SLinus Torvalds sector_t x = (sector_t)size; 2367b0576a3SGuo Chao struct block_device *bdev = lo->lo_device; 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds if (unlikely((loff_t)x != size)) 2391da177e4SLinus Torvalds return -EFBIG; 2407035b5dfSDmitry Monakhov if (lo->lo_offset != offset) 2417035b5dfSDmitry Monakhov lo->lo_offset = offset; 2427035b5dfSDmitry Monakhov if (lo->lo_sizelimit != sizelimit) 2437035b5dfSDmitry Monakhov lo->lo_sizelimit = sizelimit; 24473285082SKen Chen set_capacity(lo->lo_disk, x); 2457b0576a3SGuo Chao bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9); 2467b0576a3SGuo Chao /* let user-space know about the new size */ 2477b0576a3SGuo Chao kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); 2481da177e4SLinus Torvalds return 0; 2491da177e4SLinus Torvalds } 2501da177e4SLinus Torvalds 2511da177e4SLinus Torvalds static inline int 2521da177e4SLinus Torvalds lo_do_transfer(struct loop_device *lo, int cmd, 2531da177e4SLinus Torvalds struct page *rpage, unsigned roffs, 2541da177e4SLinus Torvalds struct page *lpage, unsigned loffs, 2551da177e4SLinus Torvalds int size, sector_t rblock) 2561da177e4SLinus Torvalds { 257aa4d8616SChristoph Hellwig int ret; 258aa4d8616SChristoph Hellwig 259aa4d8616SChristoph Hellwig ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); 260aa4d8616SChristoph Hellwig if (likely(!ret)) 2611da177e4SLinus Torvalds return 0; 2621da177e4SLinus Torvalds 263aa4d8616SChristoph Hellwig printk_ratelimited(KERN_ERR 264aa4d8616SChristoph Hellwig "loop: Transfer error at byte offset %llu, length %i.\n", 265aa4d8616SChristoph Hellwig (unsigned long long)rblock << 9, size); 266aa4d8616SChristoph Hellwig return ret; 2671da177e4SLinus Torvalds } 2681da177e4SLinus Torvalds 269aa4d8616SChristoph Hellwig static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) 2701da177e4SLinus Torvalds { 271aa4d8616SChristoph Hellwig struct iov_iter i; 2721da177e4SLinus Torvalds ssize_t bw; 273283e7e5dSAl Viro 274b6207430SChristoph Hellwig iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len); 2751da177e4SLinus Torvalds 27603d95eb2SAl Viro file_start_write(file); 277abbb6589SChristoph Hellwig bw = vfs_iter_write(file, &i, ppos, 0); 27803d95eb2SAl Viro file_end_write(file); 279aa4d8616SChristoph Hellwig 280aa4d8616SChristoph Hellwig if (likely(bw == bvec->bv_len)) 2811da177e4SLinus Torvalds return 0; 282aa4d8616SChristoph Hellwig 283aa4d8616SChristoph Hellwig printk_ratelimited(KERN_ERR 284aa4d8616SChristoph Hellwig "loop: Write error at byte offset %llu, length %i.\n", 285aa4d8616SChristoph Hellwig (unsigned long long)*ppos, bvec->bv_len); 2861da177e4SLinus Torvalds if (bw >= 0) 2871da177e4SLinus Torvalds bw = -EIO; 2881da177e4SLinus Torvalds return bw; 2891da177e4SLinus Torvalds } 2901da177e4SLinus Torvalds 291aa4d8616SChristoph Hellwig static int lo_write_simple(struct loop_device *lo, struct request *rq, 292aa4d8616SChristoph Hellwig loff_t pos) 2931da177e4SLinus Torvalds { 294aa4d8616SChristoph Hellwig struct bio_vec bvec; 295aa4d8616SChristoph Hellwig struct req_iterator iter; 296aa4d8616SChristoph Hellwig int ret = 0; 297aa4d8616SChristoph Hellwig 298aa4d8616SChristoph Hellwig rq_for_each_segment(bvec, rq, iter) { 299aa4d8616SChristoph Hellwig ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos); 300aa4d8616SChristoph Hellwig if (ret < 0) 301aa4d8616SChristoph Hellwig break; 3021da177e4SLinus Torvalds cond_resched(); 3031da177e4SLinus Torvalds } 3041da177e4SLinus Torvalds 305aa4d8616SChristoph Hellwig return ret; 306aa4d8616SChristoph Hellwig } 307aa4d8616SChristoph Hellwig 308aa4d8616SChristoph Hellwig /* 309456be148SChristoph Hellwig * This is the slow, transforming version that needs to double buffer the 310456be148SChristoph Hellwig * data as it cannot do the transformations in place without having direct 311456be148SChristoph Hellwig * access to the destination pages of the backing file. 3121da177e4SLinus Torvalds */ 313aa4d8616SChristoph Hellwig static int lo_write_transfer(struct loop_device *lo, struct request *rq, 314aa4d8616SChristoph Hellwig loff_t pos) 3151da177e4SLinus Torvalds { 316aa4d8616SChristoph Hellwig struct bio_vec bvec, b; 31730112013SMing Lei struct req_iterator iter; 318aa4d8616SChristoph Hellwig struct page *page; 3197988613bSKent Overstreet int ret = 0; 3201da177e4SLinus Torvalds 321aa4d8616SChristoph Hellwig page = alloc_page(GFP_NOIO); 3221da177e4SLinus Torvalds if (unlikely(!page)) 323aa4d8616SChristoph Hellwig return -ENOMEM; 324456be148SChristoph Hellwig 32530112013SMing Lei rq_for_each_segment(bvec, rq, iter) { 326aa4d8616SChristoph Hellwig ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page, 327aa4d8616SChristoph Hellwig bvec.bv_offset, bvec.bv_len, pos >> 9); 328aa4d8616SChristoph Hellwig if (unlikely(ret)) 329aa4d8616SChristoph Hellwig break; 330aa4d8616SChristoph Hellwig 331aa4d8616SChristoph Hellwig b.bv_page = page; 332aa4d8616SChristoph Hellwig b.bv_offset = 0; 333aa4d8616SChristoph Hellwig b.bv_len = bvec.bv_len; 334aa4d8616SChristoph Hellwig ret = lo_write_bvec(lo->lo_backing_file, &b, &pos); 3351da177e4SLinus Torvalds if (ret < 0) 3361da177e4SLinus Torvalds break; 3371da177e4SLinus Torvalds } 338aa4d8616SChristoph Hellwig 3391da177e4SLinus Torvalds __free_page(page); 3401da177e4SLinus Torvalds return ret; 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds 343aa4d8616SChristoph Hellwig static int lo_read_simple(struct loop_device *lo, struct request *rq, 344aa4d8616SChristoph Hellwig loff_t pos) 3451da177e4SLinus Torvalds { 3467988613bSKent Overstreet struct bio_vec bvec; 34730112013SMing Lei struct req_iterator iter; 348aa4d8616SChristoph Hellwig struct iov_iter i; 349aa4d8616SChristoph Hellwig ssize_t len; 3501da177e4SLinus Torvalds 35130112013SMing Lei rq_for_each_segment(bvec, rq, iter) { 352b6207430SChristoph Hellwig iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len); 35318e9710eSChristoph Hellwig len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); 354aa4d8616SChristoph Hellwig if (len < 0) 355aa4d8616SChristoph Hellwig return len; 356306df071SDave Young 357aa4d8616SChristoph Hellwig flush_dcache_page(bvec.bv_page); 358aa4d8616SChristoph Hellwig 359aa4d8616SChristoph Hellwig if (len != bvec.bv_len) { 36030112013SMing Lei struct bio *bio; 36130112013SMing Lei 36230112013SMing Lei __rq_for_each_bio(bio, rq) 363306df071SDave Young zero_fill_bio(bio); 3641da177e4SLinus Torvalds break; 365306df071SDave Young } 366aa4d8616SChristoph Hellwig cond_resched(); 3671da177e4SLinus Torvalds } 368aa4d8616SChristoph Hellwig 369306df071SDave Young return 0; 3701da177e4SLinus Torvalds } 3711da177e4SLinus Torvalds 372aa4d8616SChristoph Hellwig static int lo_read_transfer(struct loop_device *lo, struct request *rq, 373aa4d8616SChristoph Hellwig loff_t pos) 374aa4d8616SChristoph Hellwig { 375aa4d8616SChristoph Hellwig struct bio_vec bvec, b; 376aa4d8616SChristoph Hellwig struct req_iterator iter; 377aa4d8616SChristoph Hellwig struct iov_iter i; 378aa4d8616SChristoph Hellwig struct page *page; 379aa4d8616SChristoph Hellwig ssize_t len; 380aa4d8616SChristoph Hellwig int ret = 0; 381aa4d8616SChristoph Hellwig 382aa4d8616SChristoph Hellwig page = alloc_page(GFP_NOIO); 383aa4d8616SChristoph Hellwig if (unlikely(!page)) 384aa4d8616SChristoph Hellwig return -ENOMEM; 385aa4d8616SChristoph Hellwig 386aa4d8616SChristoph Hellwig rq_for_each_segment(bvec, rq, iter) { 387aa4d8616SChristoph Hellwig loff_t offset = pos; 388aa4d8616SChristoph Hellwig 389aa4d8616SChristoph Hellwig b.bv_page = page; 390aa4d8616SChristoph Hellwig b.bv_offset = 0; 391aa4d8616SChristoph Hellwig b.bv_len = bvec.bv_len; 392aa4d8616SChristoph Hellwig 393b6207430SChristoph Hellwig iov_iter_bvec(&i, READ, &b, 1, b.bv_len); 39418e9710eSChristoph Hellwig len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); 395aa4d8616SChristoph Hellwig if (len < 0) { 396aa4d8616SChristoph Hellwig ret = len; 397aa4d8616SChristoph Hellwig goto out_free_page; 398aa4d8616SChristoph Hellwig } 399aa4d8616SChristoph Hellwig 400aa4d8616SChristoph Hellwig ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page, 401aa4d8616SChristoph Hellwig bvec.bv_offset, len, offset >> 9); 402aa4d8616SChristoph Hellwig if (ret) 403aa4d8616SChristoph Hellwig goto out_free_page; 404aa4d8616SChristoph Hellwig 405aa4d8616SChristoph Hellwig flush_dcache_page(bvec.bv_page); 406aa4d8616SChristoph Hellwig 407aa4d8616SChristoph Hellwig if (len != bvec.bv_len) { 408aa4d8616SChristoph Hellwig struct bio *bio; 409aa4d8616SChristoph Hellwig 410aa4d8616SChristoph Hellwig __rq_for_each_bio(bio, rq) 411aa4d8616SChristoph Hellwig zero_fill_bio(bio); 412aa4d8616SChristoph Hellwig break; 413aa4d8616SChristoph Hellwig } 414aa4d8616SChristoph Hellwig } 415aa4d8616SChristoph Hellwig 416aa4d8616SChristoph Hellwig ret = 0; 417aa4d8616SChristoph Hellwig out_free_page: 418aa4d8616SChristoph Hellwig __free_page(page); 419aa4d8616SChristoph Hellwig return ret; 420aa4d8616SChristoph Hellwig } 421aa4d8616SChristoph Hellwig 422efcfec57SDarrick J. Wong static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos, 423efcfec57SDarrick J. Wong int mode) 424cf655d95SMing Lei { 425cf655d95SMing Lei /* 426efcfec57SDarrick J. Wong * We use fallocate to manipulate the space mappings used by the image 427efcfec57SDarrick J. Wong * a.k.a. discard/zerorange. However we do not support this if 428efcfec57SDarrick J. Wong * encryption is enabled, because it may give an attacker useful 429efcfec57SDarrick J. Wong * information. 430cf655d95SMing Lei */ 431cf655d95SMing Lei struct file *file = lo->lo_backing_file; 432cf655d95SMing Lei int ret; 433cf655d95SMing Lei 434efcfec57SDarrick J. Wong mode |= FALLOC_FL_KEEP_SIZE; 435efcfec57SDarrick J. Wong 436cf655d95SMing Lei if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { 437cf655d95SMing Lei ret = -EOPNOTSUPP; 438cf655d95SMing Lei goto out; 439cf655d95SMing Lei } 440cf655d95SMing Lei 441cf655d95SMing Lei ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); 442cf655d95SMing Lei if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) 443cf655d95SMing Lei ret = -EIO; 444cf655d95SMing Lei out: 445cf655d95SMing Lei return ret; 446cf655d95SMing Lei } 447cf655d95SMing Lei 448cf655d95SMing Lei static int lo_req_flush(struct loop_device *lo, struct request *rq) 449cf655d95SMing Lei { 450cf655d95SMing Lei struct file *file = lo->lo_backing_file; 451cf655d95SMing Lei int ret = vfs_fsync(file, 0); 452cf655d95SMing Lei if (unlikely(ret && ret != -EINVAL)) 453cf655d95SMing Lei ret = -EIO; 454cf655d95SMing Lei 455cf655d95SMing Lei return ret; 456cf655d95SMing Lei } 457cf655d95SMing Lei 458fe2cb290SChristoph Hellwig static void lo_complete_rq(struct request *rq) 459bc07c10aSMing Lei { 460fe2cb290SChristoph Hellwig struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); 461f9de14bcSJens Axboe blk_status_t ret = BLK_STS_OK; 462bc07c10aSMing Lei 463f9de14bcSJens Axboe if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || 464f9de14bcSJens Axboe req_op(rq) != REQ_OP_READ) { 465f9de14bcSJens Axboe if (cmd->ret < 0) 466*8cd55087SEvan Green ret = errno_to_blk_status(cmd->ret); 467f9de14bcSJens Axboe goto end_io; 468bc07c10aSMing Lei } 469fe2cb290SChristoph Hellwig 470f9de14bcSJens Axboe /* 471f9de14bcSJens Axboe * Short READ - if we got some data, advance our request and 472f9de14bcSJens Axboe * retry it. If we got no data, end the rest with EIO. 473f9de14bcSJens Axboe */ 474f9de14bcSJens Axboe if (cmd->ret) { 475f9de14bcSJens Axboe blk_update_request(rq, BLK_STS_OK, cmd->ret); 476f9de14bcSJens Axboe cmd->ret = 0; 477f9de14bcSJens Axboe blk_mq_requeue_request(rq, true); 478f9de14bcSJens Axboe } else { 479f9de14bcSJens Axboe if (cmd->use_aio) { 480f9de14bcSJens Axboe struct bio *bio = rq->bio; 481f9de14bcSJens Axboe 482f9de14bcSJens Axboe while (bio) { 483f9de14bcSJens Axboe zero_fill_bio(bio); 484f9de14bcSJens Axboe bio = bio->bi_next; 485f9de14bcSJens Axboe } 486f9de14bcSJens Axboe } 487f9de14bcSJens Axboe ret = BLK_STS_IOERR; 488f9de14bcSJens Axboe end_io: 489f9de14bcSJens Axboe blk_mq_end_request(rq, ret); 490f9de14bcSJens Axboe } 491bc07c10aSMing Lei } 492bc07c10aSMing Lei 49392d77332SShaohua Li static void lo_rw_aio_do_completion(struct loop_cmd *cmd) 49492d77332SShaohua Li { 4951894e916SJens Axboe struct request *rq = blk_mq_rq_from_pdu(cmd); 4961894e916SJens Axboe 49792d77332SShaohua Li if (!atomic_dec_and_test(&cmd->ref)) 49892d77332SShaohua Li return; 49992d77332SShaohua Li kfree(cmd->bvec); 50092d77332SShaohua Li cmd->bvec = NULL; 5011894e916SJens Axboe blk_mq_complete_request(rq); 50292d77332SShaohua Li } 50392d77332SShaohua Li 504bc07c10aSMing Lei static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) 505bc07c10aSMing Lei { 506bc07c10aSMing Lei struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); 507bc07c10aSMing Lei 508d4478e92SShaohua Li if (cmd->css) 509d4478e92SShaohua Li css_put(cmd->css); 510fe2cb290SChristoph Hellwig cmd->ret = ret; 51192d77332SShaohua Li lo_rw_aio_do_completion(cmd); 512bc07c10aSMing Lei } 513bc07c10aSMing Lei 514bc07c10aSMing Lei static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, 515bc07c10aSMing Lei loff_t pos, bool rw) 516bc07c10aSMing Lei { 517bc07c10aSMing Lei struct iov_iter iter; 51886af5952SMing Lei struct req_iterator rq_iter; 519bc07c10aSMing Lei struct bio_vec *bvec; 5201894e916SJens Axboe struct request *rq = blk_mq_rq_from_pdu(cmd); 52140326d8aSShaohua Li struct bio *bio = rq->bio; 522bc07c10aSMing Lei struct file *file = lo->lo_backing_file; 52386af5952SMing Lei struct bio_vec tmp; 52440326d8aSShaohua Li unsigned int offset; 52586af5952SMing Lei int nr_bvec = 0; 526bc07c10aSMing Lei int ret; 527bc07c10aSMing Lei 52886af5952SMing Lei rq_for_each_bvec(tmp, rq, rq_iter) 52986af5952SMing Lei nr_bvec++; 530bc07c10aSMing Lei 53186af5952SMing Lei if (rq->bio != rq->biotail) { 53286af5952SMing Lei 53386af5952SMing Lei bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), 5346da2ec56SKees Cook GFP_NOIO); 53540326d8aSShaohua Li if (!bvec) 53640326d8aSShaohua Li return -EIO; 53740326d8aSShaohua Li cmd->bvec = bvec; 53840326d8aSShaohua Li 539a7297a6aSMing Lei /* 54040326d8aSShaohua Li * The bios of the request may be started from the middle of 54140326d8aSShaohua Li * the 'bvec' because of bio splitting, so we can't directly 54286af5952SMing Lei * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec 54340326d8aSShaohua Li * API will take care of all details for us. 544a7297a6aSMing Lei */ 54586af5952SMing Lei rq_for_each_bvec(tmp, rq, rq_iter) { 54640326d8aSShaohua Li *bvec = tmp; 54740326d8aSShaohua Li bvec++; 54840326d8aSShaohua Li } 54940326d8aSShaohua Li bvec = cmd->bvec; 55040326d8aSShaohua Li offset = 0; 55140326d8aSShaohua Li } else { 55240326d8aSShaohua Li /* 55340326d8aSShaohua Li * Same here, this bio may be started from the middle of the 55440326d8aSShaohua Li * 'bvec' because of bio splitting, so offset from the bvec 55540326d8aSShaohua Li * must be passed to iov iterator 55640326d8aSShaohua Li */ 55740326d8aSShaohua Li offset = bio->bi_iter.bi_bvec_done; 55840326d8aSShaohua Li bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); 55940326d8aSShaohua Li } 56092d77332SShaohua Li atomic_set(&cmd->ref, 2); 56140326d8aSShaohua Li 562b6207430SChristoph Hellwig iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); 56340326d8aSShaohua Li iter.iov_offset = offset; 564bc07c10aSMing Lei 565bc07c10aSMing Lei cmd->iocb.ki_pos = pos; 566bc07c10aSMing Lei cmd->iocb.ki_filp = file; 567bc07c10aSMing Lei cmd->iocb.ki_complete = lo_rw_aio_complete; 568bc07c10aSMing Lei cmd->iocb.ki_flags = IOCB_DIRECT; 569d9a08a9eSAdam Manzanares cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); 570d4478e92SShaohua Li if (cmd->css) 571d4478e92SShaohua Li kthread_associate_blkcg(cmd->css); 572bc07c10aSMing Lei 573bc07c10aSMing Lei if (rw == WRITE) 574bb7462b6SMiklos Szeredi ret = call_write_iter(file, &cmd->iocb, &iter); 575bc07c10aSMing Lei else 576bb7462b6SMiklos Szeredi ret = call_read_iter(file, &cmd->iocb, &iter); 577bc07c10aSMing Lei 57892d77332SShaohua Li lo_rw_aio_do_completion(cmd); 579d4478e92SShaohua Li kthread_associate_blkcg(NULL); 58092d77332SShaohua Li 581bc07c10aSMing Lei if (ret != -EIOCBQUEUED) 582bc07c10aSMing Lei cmd->iocb.ki_complete(&cmd->iocb, ret, 0); 583bc07c10aSMing Lei return 0; 584bc07c10aSMing Lei } 585bc07c10aSMing Lei 586c1c87c2bSChristoph Hellwig static int do_req_filebacked(struct loop_device *lo, struct request *rq) 587bc07c10aSMing Lei { 588bc07c10aSMing Lei struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); 589c1c87c2bSChristoph Hellwig loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; 590bc07c10aSMing Lei 591bc07c10aSMing Lei /* 592bc07c10aSMing Lei * lo_write_simple and lo_read_simple should have been covered 593bc07c10aSMing Lei * by io submit style function like lo_rw_aio(), one blocker 594bc07c10aSMing Lei * is that lo_read_simple() need to call flush_dcache_page after 595bc07c10aSMing Lei * the page is written from kernel, and it isn't easy to handle 596bc07c10aSMing Lei * this in io submit style function which submits all segments 597bc07c10aSMing Lei * of the req at one time. And direct read IO doesn't need to 598bc07c10aSMing Lei * run flush_dcache_page(). 599bc07c10aSMing Lei */ 600c1c87c2bSChristoph Hellwig switch (req_op(rq)) { 601c1c87c2bSChristoph Hellwig case REQ_OP_FLUSH: 602c1c87c2bSChristoph Hellwig return lo_req_flush(lo, rq); 60319372e27SChristoph Hellwig case REQ_OP_WRITE_ZEROES: 604efcfec57SDarrick J. Wong /* 605efcfec57SDarrick J. Wong * If the caller doesn't want deallocation, call zeroout to 606efcfec57SDarrick J. Wong * write zeroes the range. Otherwise, punch them out. 607efcfec57SDarrick J. Wong */ 608efcfec57SDarrick J. Wong return lo_fallocate(lo, rq, pos, 609efcfec57SDarrick J. Wong (rq->cmd_flags & REQ_NOUNMAP) ? 610efcfec57SDarrick J. Wong FALLOC_FL_ZERO_RANGE : 611efcfec57SDarrick J. Wong FALLOC_FL_PUNCH_HOLE); 612efcfec57SDarrick J. Wong case REQ_OP_DISCARD: 613efcfec57SDarrick J. Wong return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE); 614c1c87c2bSChristoph Hellwig case REQ_OP_WRITE: 615c1c87c2bSChristoph Hellwig if (lo->transfer) 616c1c87c2bSChristoph Hellwig return lo_write_transfer(lo, rq, pos); 617c1c87c2bSChristoph Hellwig else if (cmd->use_aio) 618c1c87c2bSChristoph Hellwig return lo_rw_aio(lo, cmd, pos, WRITE); 619c1c87c2bSChristoph Hellwig else 620bc07c10aSMing Lei return lo_write_simple(lo, rq, pos); 621c1c87c2bSChristoph Hellwig case REQ_OP_READ: 622c1c87c2bSChristoph Hellwig if (lo->transfer) 623c1c87c2bSChristoph Hellwig return lo_read_transfer(lo, rq, pos); 624c1c87c2bSChristoph Hellwig else if (cmd->use_aio) 625c1c87c2bSChristoph Hellwig return lo_rw_aio(lo, cmd, pos, READ); 626bc07c10aSMing Lei else 627bc07c10aSMing Lei return lo_read_simple(lo, rq, pos); 628c1c87c2bSChristoph Hellwig default: 629c1c87c2bSChristoph Hellwig WARN_ON_ONCE(1); 630c1c87c2bSChristoph Hellwig return -EIO; 631bc07c10aSMing Lei } 6321da177e4SLinus Torvalds } 6331da177e4SLinus Torvalds 6342e5ab5f3SMing Lei static inline void loop_update_dio(struct loop_device *lo) 6352e5ab5f3SMing Lei { 6362e5ab5f3SMing Lei __loop_update_dio(lo, io_is_direct(lo->lo_backing_file) | 6372e5ab5f3SMing Lei lo->use_dio); 6382e5ab5f3SMing Lei } 6392e5ab5f3SMing Lei 64006f0e9e6SMing Lei static void loop_reread_partitions(struct loop_device *lo, 64106f0e9e6SMing Lei struct block_device *bdev) 64206f0e9e6SMing Lei { 64306f0e9e6SMing Lei int rc; 64406f0e9e6SMing Lei 645f0b870dfSChristoph Hellwig mutex_lock(&bdev->bd_mutex); 646f0b870dfSChristoph Hellwig rc = bdev_disk_changed(bdev, false); 647f0b870dfSChristoph Hellwig mutex_unlock(&bdev->bd_mutex); 64806f0e9e6SMing Lei if (rc) 64906f0e9e6SMing Lei pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", 65006f0e9e6SMing Lei __func__, lo->lo_number, lo->lo_file_name, rc); 65106f0e9e6SMing Lei } 65206f0e9e6SMing Lei 653d2ac838eSTheodore Ts'o static inline int is_loop_device(struct file *file) 654d2ac838eSTheodore Ts'o { 655d2ac838eSTheodore Ts'o struct inode *i = file->f_mapping->host; 656d2ac838eSTheodore Ts'o 657d2ac838eSTheodore Ts'o return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; 658d2ac838eSTheodore Ts'o } 659d2ac838eSTheodore Ts'o 660d2ac838eSTheodore Ts'o static int loop_validate_file(struct file *file, struct block_device *bdev) 661d2ac838eSTheodore Ts'o { 662d2ac838eSTheodore Ts'o struct inode *inode = file->f_mapping->host; 663d2ac838eSTheodore Ts'o struct file *f = file; 664d2ac838eSTheodore Ts'o 665d2ac838eSTheodore Ts'o /* Avoid recursion */ 666d2ac838eSTheodore Ts'o while (is_loop_device(f)) { 667d2ac838eSTheodore Ts'o struct loop_device *l; 668d2ac838eSTheodore Ts'o 669d2ac838eSTheodore Ts'o if (f->f_mapping->host->i_bdev == bdev) 670d2ac838eSTheodore Ts'o return -EBADF; 671d2ac838eSTheodore Ts'o 672d2ac838eSTheodore Ts'o l = f->f_mapping->host->i_bdev->bd_disk->private_data; 673f7c8a412SDongli Zhang if (l->lo_state != Lo_bound) { 674d2ac838eSTheodore Ts'o return -EINVAL; 675d2ac838eSTheodore Ts'o } 676d2ac838eSTheodore Ts'o f = l->lo_backing_file; 677d2ac838eSTheodore Ts'o } 678d2ac838eSTheodore Ts'o if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) 679d2ac838eSTheodore Ts'o return -EINVAL; 680d2ac838eSTheodore Ts'o return 0; 681d2ac838eSTheodore Ts'o } 682d2ac838eSTheodore Ts'o 6831da177e4SLinus Torvalds /* 6841da177e4SLinus Torvalds * loop_change_fd switched the backing store of a loopback device to 6851da177e4SLinus Torvalds * a new file. This is useful for operating system installers to free up 6861da177e4SLinus Torvalds * the original file and in High Availability environments to switch to 6871da177e4SLinus Torvalds * an alternative location for the content in case of server meltdown. 6881da177e4SLinus Torvalds * This can only work if the loop device is used read-only, and if the 6891da177e4SLinus Torvalds * new backing store is the same size and type as the old backing store. 6901da177e4SLinus Torvalds */ 691bb214884SAl Viro static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, 692bb214884SAl Viro unsigned int arg) 6931da177e4SLinus Torvalds { 6941dded9acSJan Kara struct file *file = NULL, *old_file; 6951da177e4SLinus Torvalds int error; 69685b0a54aSJan Kara bool partscan; 6971da177e4SLinus Torvalds 698c28445faSJan Kara error = mutex_lock_killable(&loop_ctl_mutex); 699c3710770SJan Kara if (error) 700c3710770SJan Kara return error; 7011da177e4SLinus Torvalds error = -ENXIO; 7021da177e4SLinus Torvalds if (lo->lo_state != Lo_bound) 7031dded9acSJan Kara goto out_err; 7041da177e4SLinus Torvalds 7051da177e4SLinus Torvalds /* the loop device has to be read-only */ 7061da177e4SLinus Torvalds error = -EINVAL; 7071da177e4SLinus Torvalds if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) 7081dded9acSJan Kara goto out_err; 7091da177e4SLinus Torvalds 7101da177e4SLinus Torvalds error = -EBADF; 7111da177e4SLinus Torvalds file = fget(arg); 7121da177e4SLinus Torvalds if (!file) 7131dded9acSJan Kara goto out_err; 7141da177e4SLinus Torvalds 715d2ac838eSTheodore Ts'o error = loop_validate_file(file, bdev); 716d2ac838eSTheodore Ts'o if (error) 7171dded9acSJan Kara goto out_err; 718d2ac838eSTheodore Ts'o 7191da177e4SLinus Torvalds old_file = lo->lo_backing_file; 7201da177e4SLinus Torvalds 7211da177e4SLinus Torvalds error = -EINVAL; 7221da177e4SLinus Torvalds 7231da177e4SLinus Torvalds /* size of the new backing store needs to be the same */ 7241da177e4SLinus Torvalds if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) 7251dded9acSJan Kara goto out_err; 7261da177e4SLinus Torvalds 7271da177e4SLinus Torvalds /* and ... switch */ 72843cade80SOmar Sandoval blk_mq_freeze_queue(lo->lo_queue); 72943cade80SOmar Sandoval mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); 73043cade80SOmar Sandoval lo->lo_backing_file = file; 73143cade80SOmar Sandoval lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping); 73243cade80SOmar Sandoval mapping_set_gfp_mask(file->f_mapping, 73343cade80SOmar Sandoval lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); 73443cade80SOmar Sandoval loop_update_dio(lo); 73543cade80SOmar Sandoval blk_mq_unfreeze_queue(lo->lo_queue); 73685b0a54aSJan Kara partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; 737c3710770SJan Kara mutex_unlock(&loop_ctl_mutex); 7381dded9acSJan Kara /* 7391dded9acSJan Kara * We must drop file reference outside of loop_ctl_mutex as dropping 7401dded9acSJan Kara * the file ref can take bd_mutex which creates circular locking 7411dded9acSJan Kara * dependency. 7421dded9acSJan Kara */ 7431dded9acSJan Kara fput(old_file); 74485b0a54aSJan Kara if (partscan) 74585b0a54aSJan Kara loop_reread_partitions(lo, bdev); 7461da177e4SLinus Torvalds return 0; 7471da177e4SLinus Torvalds 7481dded9acSJan Kara out_err: 749c3710770SJan Kara mutex_unlock(&loop_ctl_mutex); 7501dded9acSJan Kara if (file) 7511dded9acSJan Kara fput(file); 7521da177e4SLinus Torvalds return error; 7531da177e4SLinus Torvalds } 7541da177e4SLinus Torvalds 755ee862730SMilan Broz /* loop sysfs attributes */ 756ee862730SMilan Broz 757ee862730SMilan Broz static ssize_t loop_attr_show(struct device *dev, char *page, 758ee862730SMilan Broz ssize_t (*callback)(struct loop_device *, char *)) 759ee862730SMilan Broz { 76034dd82afSKay Sievers struct gendisk *disk = dev_to_disk(dev); 76134dd82afSKay Sievers struct loop_device *lo = disk->private_data; 762ee862730SMilan Broz 76334dd82afSKay Sievers return callback(lo, page); 764ee862730SMilan Broz } 765ee862730SMilan Broz 766ee862730SMilan Broz #define LOOP_ATTR_RO(_name) \ 767ee862730SMilan Broz static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \ 768ee862730SMilan Broz static ssize_t loop_attr_do_show_##_name(struct device *d, \ 769ee862730SMilan Broz struct device_attribute *attr, char *b) \ 770ee862730SMilan Broz { \ 771ee862730SMilan Broz return loop_attr_show(d, b, loop_attr_##_name##_show); \ 772ee862730SMilan Broz } \ 773ee862730SMilan Broz static struct device_attribute loop_attr_##_name = \ 7745657a819SJoe Perches __ATTR(_name, 0444, loop_attr_do_show_##_name, NULL); 775ee862730SMilan Broz 776ee862730SMilan Broz static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) 777ee862730SMilan Broz { 778ee862730SMilan Broz ssize_t ret; 779ee862730SMilan Broz char *p = NULL; 780ee862730SMilan Broz 78105eb0f25SKay Sievers spin_lock_irq(&lo->lo_lock); 782ee862730SMilan Broz if (lo->lo_backing_file) 7839bf39ab2SMiklos Szeredi p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1); 78405eb0f25SKay Sievers spin_unlock_irq(&lo->lo_lock); 785ee862730SMilan Broz 786ee862730SMilan Broz if (IS_ERR_OR_NULL(p)) 787ee862730SMilan Broz ret = PTR_ERR(p); 788ee862730SMilan Broz else { 789ee862730SMilan Broz ret = strlen(p); 790ee862730SMilan Broz memmove(buf, p, ret); 791ee862730SMilan Broz buf[ret++] = '\n'; 792ee862730SMilan Broz buf[ret] = 0; 793ee862730SMilan Broz } 794ee862730SMilan Broz 795ee862730SMilan Broz return ret; 796ee862730SMilan Broz } 797ee862730SMilan Broz 798ee862730SMilan Broz static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf) 799ee862730SMilan Broz { 800ee862730SMilan Broz return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset); 801ee862730SMilan Broz } 802ee862730SMilan Broz 803ee862730SMilan Broz static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf) 804ee862730SMilan Broz { 805ee862730SMilan Broz return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit); 806ee862730SMilan Broz } 807ee862730SMilan Broz 808ee862730SMilan Broz static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf) 809ee862730SMilan Broz { 810ee862730SMilan Broz int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR); 811ee862730SMilan Broz 812ee862730SMilan Broz return sprintf(buf, "%s\n", autoclear ? "1" : "0"); 813ee862730SMilan Broz } 814ee862730SMilan Broz 815e03c8dd1SKay Sievers static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf) 816e03c8dd1SKay Sievers { 817e03c8dd1SKay Sievers int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN); 818e03c8dd1SKay Sievers 819e03c8dd1SKay Sievers return sprintf(buf, "%s\n", partscan ? "1" : "0"); 820e03c8dd1SKay Sievers } 821e03c8dd1SKay Sievers 8222e5ab5f3SMing Lei static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf) 8232e5ab5f3SMing Lei { 8242e5ab5f3SMing Lei int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO); 8252e5ab5f3SMing Lei 8262e5ab5f3SMing Lei return sprintf(buf, "%s\n", dio ? "1" : "0"); 8272e5ab5f3SMing Lei } 8282e5ab5f3SMing Lei 829ee862730SMilan Broz LOOP_ATTR_RO(backing_file); 830ee862730SMilan Broz LOOP_ATTR_RO(offset); 831ee862730SMilan Broz LOOP_ATTR_RO(sizelimit); 832ee862730SMilan Broz LOOP_ATTR_RO(autoclear); 833e03c8dd1SKay Sievers LOOP_ATTR_RO(partscan); 8342e5ab5f3SMing Lei LOOP_ATTR_RO(dio); 835ee862730SMilan Broz 836ee862730SMilan Broz static struct attribute *loop_attrs[] = { 837ee862730SMilan Broz &loop_attr_backing_file.attr, 838ee862730SMilan Broz &loop_attr_offset.attr, 839ee862730SMilan Broz &loop_attr_sizelimit.attr, 840ee862730SMilan Broz &loop_attr_autoclear.attr, 841e03c8dd1SKay Sievers &loop_attr_partscan.attr, 8422e5ab5f3SMing Lei &loop_attr_dio.attr, 843ee862730SMilan Broz NULL, 844ee862730SMilan Broz }; 845ee862730SMilan Broz 846ee862730SMilan Broz static struct attribute_group loop_attribute_group = { 847ee862730SMilan Broz .name = "loop", 848ee862730SMilan Broz .attrs= loop_attrs, 849ee862730SMilan Broz }; 850ee862730SMilan Broz 851d3349b6bSTetsuo Handa static void loop_sysfs_init(struct loop_device *lo) 852ee862730SMilan Broz { 853d3349b6bSTetsuo Handa lo->sysfs_inited = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, 854ee862730SMilan Broz &loop_attribute_group); 855ee862730SMilan Broz } 856ee862730SMilan Broz 857ee862730SMilan Broz static void loop_sysfs_exit(struct loop_device *lo) 858ee862730SMilan Broz { 859d3349b6bSTetsuo Handa if (lo->sysfs_inited) 860ee862730SMilan Broz sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj, 861ee862730SMilan Broz &loop_attribute_group); 862ee862730SMilan Broz } 863ee862730SMilan Broz 864dfaa2ef6SLukas Czerner static void loop_config_discard(struct loop_device *lo) 865dfaa2ef6SLukas Czerner { 866dfaa2ef6SLukas Czerner struct file *file = lo->lo_backing_file; 867dfaa2ef6SLukas Czerner struct inode *inode = file->f_mapping->host; 868dfaa2ef6SLukas Czerner struct request_queue *q = lo->lo_queue; 869dfaa2ef6SLukas Czerner 870dfaa2ef6SLukas Czerner /* 871dfaa2ef6SLukas Czerner * We use punch hole to reclaim the free space used by the 87212a64d2fSOlaf Hering * image a.k.a. discard. However we do not support discard if 873dfaa2ef6SLukas Czerner * encryption is enabled, because it may give an attacker 874dfaa2ef6SLukas Czerner * useful information. 875dfaa2ef6SLukas Czerner */ 876dfaa2ef6SLukas Czerner if ((!file->f_op->fallocate) || 877dfaa2ef6SLukas Czerner lo->lo_encrypt_key_size) { 878dfaa2ef6SLukas Czerner q->limits.discard_granularity = 0; 879dfaa2ef6SLukas Czerner q->limits.discard_alignment = 0; 8802bb4cd5cSJens Axboe blk_queue_max_discard_sectors(q, 0); 88119372e27SChristoph Hellwig blk_queue_max_write_zeroes_sectors(q, 0); 8828b904b5bSBart Van Assche blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); 883dfaa2ef6SLukas Czerner return; 884dfaa2ef6SLukas Czerner } 885dfaa2ef6SLukas Czerner 886dfaa2ef6SLukas Czerner q->limits.discard_granularity = inode->i_sb->s_blocksize; 887dfaf3c03SLukas Czerner q->limits.discard_alignment = 0; 888f2c6df7dSHannes Reinecke 8891e6ec9eaSOmar Sandoval blk_queue_max_discard_sectors(q, UINT_MAX >> 9); 8901e6ec9eaSOmar Sandoval blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); 8918b904b5bSBart Van Assche blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); 892dfaa2ef6SLukas Czerner } 893dfaa2ef6SLukas Czerner 894e03a3d7aSMing Lei static void loop_unprepare_queue(struct loop_device *lo) 895e03a3d7aSMing Lei { 8963989144fSPetr Mladek kthread_flush_worker(&lo->worker); 897e03a3d7aSMing Lei kthread_stop(lo->worker_task); 898e03a3d7aSMing Lei } 899e03a3d7aSMing Lei 900b2ee7d46SNeilBrown static int loop_kthread_worker_fn(void *worker_ptr) 901b2ee7d46SNeilBrown { 902d0a255e7SMikulas Patocka current->flags |= PF_LESS_THROTTLE | PF_MEMALLOC_NOIO; 903b2ee7d46SNeilBrown return kthread_worker_fn(worker_ptr); 904b2ee7d46SNeilBrown } 905b2ee7d46SNeilBrown 906e03a3d7aSMing Lei static int loop_prepare_queue(struct loop_device *lo) 907e03a3d7aSMing Lei { 9083989144fSPetr Mladek kthread_init_worker(&lo->worker); 909b2ee7d46SNeilBrown lo->worker_task = kthread_run(loop_kthread_worker_fn, 910e03a3d7aSMing Lei &lo->worker, "loop%d", lo->lo_number); 911e03a3d7aSMing Lei if (IS_ERR(lo->worker_task)) 912e03a3d7aSMing Lei return -ENOMEM; 913e03a3d7aSMing Lei set_user_nice(lo->worker_task, MIN_NICE); 914e03a3d7aSMing Lei return 0; 915e03a3d7aSMing Lei } 916e03a3d7aSMing Lei 91756a85fd8SHolger Hoffstätte static void loop_update_rotational(struct loop_device *lo) 91856a85fd8SHolger Hoffstätte { 91956a85fd8SHolger Hoffstätte struct file *file = lo->lo_backing_file; 92056a85fd8SHolger Hoffstätte struct inode *file_inode = file->f_mapping->host; 92156a85fd8SHolger Hoffstätte struct block_device *file_bdev = file_inode->i_sb->s_bdev; 92256a85fd8SHolger Hoffstätte struct request_queue *q = lo->lo_queue; 92356a85fd8SHolger Hoffstätte bool nonrot = true; 92456a85fd8SHolger Hoffstätte 92556a85fd8SHolger Hoffstätte /* not all filesystems (e.g. tmpfs) have a sb->s_bdev */ 92656a85fd8SHolger Hoffstätte if (file_bdev) 92756a85fd8SHolger Hoffstätte nonrot = blk_queue_nonrot(bdev_get_queue(file_bdev)); 92856a85fd8SHolger Hoffstätte 92956a85fd8SHolger Hoffstätte if (nonrot) 93056a85fd8SHolger Hoffstätte blk_queue_flag_set(QUEUE_FLAG_NONROT, q); 93156a85fd8SHolger Hoffstätte else 93256a85fd8SHolger Hoffstätte blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); 93356a85fd8SHolger Hoffstätte } 93456a85fd8SHolger Hoffstätte 935bb214884SAl Viro static int loop_set_fd(struct loop_device *lo, fmode_t mode, 9361da177e4SLinus Torvalds struct block_device *bdev, unsigned int arg) 9371da177e4SLinus Torvalds { 938d2ac838eSTheodore Ts'o struct file *file; 9391da177e4SLinus Torvalds struct inode *inode; 9401da177e4SLinus Torvalds struct address_space *mapping; 94189e524c0SJan Kara struct block_device *claimed_bdev = NULL; 9421da177e4SLinus Torvalds int lo_flags = 0; 9431da177e4SLinus Torvalds int error; 9441da177e4SLinus Torvalds loff_t size; 94585b0a54aSJan Kara bool partscan; 9461da177e4SLinus Torvalds 9471da177e4SLinus Torvalds /* This is safe, since we have a reference from open(). */ 9481da177e4SLinus Torvalds __module_get(THIS_MODULE); 9491da177e4SLinus Torvalds 9501da177e4SLinus Torvalds error = -EBADF; 9511da177e4SLinus Torvalds file = fget(arg); 9521da177e4SLinus Torvalds if (!file) 9531da177e4SLinus Torvalds goto out; 9541da177e4SLinus Torvalds 95533ec3e53SJan Kara /* 95633ec3e53SJan Kara * If we don't hold exclusive handle for the device, upgrade to it 95733ec3e53SJan Kara * here to avoid changing device under exclusive owner. 95833ec3e53SJan Kara */ 95933ec3e53SJan Kara if (!(mode & FMODE_EXCL)) { 96089e524c0SJan Kara claimed_bdev = bd_start_claiming(bdev, loop_set_fd); 96189e524c0SJan Kara if (IS_ERR(claimed_bdev)) { 96289e524c0SJan Kara error = PTR_ERR(claimed_bdev); 963757ecf40SJan Kara goto out_putf; 96433ec3e53SJan Kara } 96589e524c0SJan Kara } 96633ec3e53SJan Kara 96733ec3e53SJan Kara error = mutex_lock_killable(&loop_ctl_mutex); 96833ec3e53SJan Kara if (error) 96933ec3e53SJan Kara goto out_bdev; 970757ecf40SJan Kara 9711da177e4SLinus Torvalds error = -EBUSY; 9721da177e4SLinus Torvalds if (lo->lo_state != Lo_unbound) 973757ecf40SJan Kara goto out_unlock; 9741da177e4SLinus Torvalds 975d2ac838eSTheodore Ts'o error = loop_validate_file(file, bdev); 976d2ac838eSTheodore Ts'o if (error) 977757ecf40SJan Kara goto out_unlock; 9781da177e4SLinus Torvalds 9791da177e4SLinus Torvalds mapping = file->f_mapping; 9801da177e4SLinus Torvalds inode = mapping->host; 9811da177e4SLinus Torvalds 982456be148SChristoph Hellwig if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || 983283e7e5dSAl Viro !file->f_op->write_iter) 9841da177e4SLinus Torvalds lo_flags |= LO_FLAGS_READ_ONLY; 9851da177e4SLinus Torvalds 9861da177e4SLinus Torvalds error = -EFBIG; 987456be148SChristoph Hellwig size = get_loop_size(lo, file); 988456be148SChristoph Hellwig if ((loff_t)(sector_t)size != size) 989757ecf40SJan Kara goto out_unlock; 990e03a3d7aSMing Lei error = loop_prepare_queue(lo); 991e03a3d7aSMing Lei if (error) 992757ecf40SJan Kara goto out_unlock; 9931da177e4SLinus Torvalds 994456be148SChristoph Hellwig error = 0; 9951da177e4SLinus Torvalds 9961da177e4SLinus Torvalds set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); 9971da177e4SLinus Torvalds 9982e5ab5f3SMing Lei lo->use_dio = false; 9991da177e4SLinus Torvalds lo->lo_device = bdev; 10001da177e4SLinus Torvalds lo->lo_flags = lo_flags; 10011da177e4SLinus Torvalds lo->lo_backing_file = file; 1002aa4d8616SChristoph Hellwig lo->transfer = NULL; 10031da177e4SLinus Torvalds lo->ioctl = NULL; 10041da177e4SLinus Torvalds lo->lo_sizelimit = 0; 10051da177e4SLinus Torvalds lo->old_gfp_mask = mapping_gfp_mask(mapping); 10061da177e4SLinus Torvalds mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); 10071da177e4SLinus Torvalds 100868db1961SNikanth Karthikesan if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) 100921d0727fSJens Axboe blk_queue_write_cache(lo->lo_queue, true, false); 101068db1961SNikanth Karthikesan 101185560117SMartijn Coenen if (io_is_direct(lo->lo_backing_file) && inode->i_sb->s_bdev) { 101285560117SMartijn Coenen /* In case of direct I/O, match underlying block size */ 101385560117SMartijn Coenen unsigned short bsize = bdev_logical_block_size( 101485560117SMartijn Coenen inode->i_sb->s_bdev); 101585560117SMartijn Coenen 101685560117SMartijn Coenen blk_queue_logical_block_size(lo->lo_queue, bsize); 101785560117SMartijn Coenen blk_queue_physical_block_size(lo->lo_queue, bsize); 101885560117SMartijn Coenen blk_queue_io_min(lo->lo_queue, bsize); 101985560117SMartijn Coenen } 102085560117SMartijn Coenen 102156a85fd8SHolger Hoffstätte loop_update_rotational(lo); 10222e5ab5f3SMing Lei loop_update_dio(lo); 102373285082SKen Chen set_capacity(lo->lo_disk, size); 10241da177e4SLinus Torvalds bd_set_size(bdev, size << 9); 1025ee862730SMilan Broz loop_sysfs_init(lo); 1026c3473c63SDavid Zeuthen /* let user-space know about the new size */ 1027c3473c63SDavid Zeuthen kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); 10281da177e4SLinus Torvalds 10298a0740c4SOmar Sandoval set_blocksize(bdev, S_ISBLK(inode->i_mode) ? 10308a0740c4SOmar Sandoval block_size(inode->i_bdev) : PAGE_SIZE); 10311da177e4SLinus Torvalds 10326c997918SSerge E. Hallyn lo->lo_state = Lo_bound; 1033e03c8dd1SKay Sievers if (part_shift) 1034e03c8dd1SKay Sievers lo->lo_flags |= LO_FLAGS_PARTSCAN; 103585b0a54aSJan Kara partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; 1036c1681bf8SAnatol Pomozov 1037c1681bf8SAnatol Pomozov /* Grab the block_device to prevent its destruction after we 1038a2505b79SJan Kara * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev). 1039c1681bf8SAnatol Pomozov */ 1040c1681bf8SAnatol Pomozov bdgrab(bdev); 1041757ecf40SJan Kara mutex_unlock(&loop_ctl_mutex); 104285b0a54aSJan Kara if (partscan) 104385b0a54aSJan Kara loop_reread_partitions(lo, bdev); 104489e524c0SJan Kara if (claimed_bdev) 104589e524c0SJan Kara bd_abort_claiming(bdev, claimed_bdev, loop_set_fd); 10461da177e4SLinus Torvalds return 0; 10471da177e4SLinus Torvalds 1048757ecf40SJan Kara out_unlock: 1049757ecf40SJan Kara mutex_unlock(&loop_ctl_mutex); 105033ec3e53SJan Kara out_bdev: 105189e524c0SJan Kara if (claimed_bdev) 105289e524c0SJan Kara bd_abort_claiming(bdev, claimed_bdev, loop_set_fd); 10531da177e4SLinus Torvalds out_putf: 10541da177e4SLinus Torvalds fput(file); 10551da177e4SLinus Torvalds out: 10561da177e4SLinus Torvalds /* This is safe: open() is still holding a reference. */ 10571da177e4SLinus Torvalds module_put(THIS_MODULE); 10581da177e4SLinus Torvalds return error; 10591da177e4SLinus Torvalds } 10601da177e4SLinus Torvalds 10611da177e4SLinus Torvalds static int 10621da177e4SLinus Torvalds loop_release_xfer(struct loop_device *lo) 10631da177e4SLinus Torvalds { 10641da177e4SLinus Torvalds int err = 0; 10651da177e4SLinus Torvalds struct loop_func_table *xfer = lo->lo_encryption; 10661da177e4SLinus Torvalds 10671da177e4SLinus Torvalds if (xfer) { 10681da177e4SLinus Torvalds if (xfer->release) 10691da177e4SLinus Torvalds err = xfer->release(lo); 10701da177e4SLinus Torvalds lo->transfer = NULL; 10711da177e4SLinus Torvalds lo->lo_encryption = NULL; 10721da177e4SLinus Torvalds module_put(xfer->owner); 10731da177e4SLinus Torvalds } 10741da177e4SLinus Torvalds return err; 10751da177e4SLinus Torvalds } 10761da177e4SLinus Torvalds 10771da177e4SLinus Torvalds static int 10781da177e4SLinus Torvalds loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, 10791da177e4SLinus Torvalds const struct loop_info64 *i) 10801da177e4SLinus Torvalds { 10811da177e4SLinus Torvalds int err = 0; 10821da177e4SLinus Torvalds 10831da177e4SLinus Torvalds if (xfer) { 10841da177e4SLinus Torvalds struct module *owner = xfer->owner; 10851da177e4SLinus Torvalds 10861da177e4SLinus Torvalds if (!try_module_get(owner)) 10871da177e4SLinus Torvalds return -EINVAL; 10881da177e4SLinus Torvalds if (xfer->init) 10891da177e4SLinus Torvalds err = xfer->init(lo, i); 10901da177e4SLinus Torvalds if (err) 10911da177e4SLinus Torvalds module_put(owner); 10921da177e4SLinus Torvalds else 10931da177e4SLinus Torvalds lo->lo_encryption = xfer; 10941da177e4SLinus Torvalds } 10951da177e4SLinus Torvalds return err; 10961da177e4SLinus Torvalds } 10971da177e4SLinus Torvalds 10980da03cabSJan Kara static int __loop_clr_fd(struct loop_device *lo, bool release) 10991da177e4SLinus Torvalds { 11007ccd0791SJan Kara struct file *filp = NULL; 1101b4e3ca1aSAl Viro gfp_t gfp = lo->old_gfp_mask; 11024c823cc3SAyan George struct block_device *bdev = lo->lo_device; 11037ccd0791SJan Kara int err = 0; 11040da03cabSJan Kara bool partscan = false; 11050da03cabSJan Kara int lo_number; 11061da177e4SLinus Torvalds 11077ccd0791SJan Kara mutex_lock(&loop_ctl_mutex); 11087ccd0791SJan Kara if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) { 11097ccd0791SJan Kara err = -ENXIO; 11107ccd0791SJan Kara goto out_unlock; 11117ccd0791SJan Kara } 11121da177e4SLinus Torvalds 11137ccd0791SJan Kara filp = lo->lo_backing_file; 11147ccd0791SJan Kara if (filp == NULL) { 11157ccd0791SJan Kara err = -EINVAL; 11167ccd0791SJan Kara goto out_unlock; 11177ccd0791SJan Kara } 11181da177e4SLinus Torvalds 1119f8933667SMing Lei /* freeze request queue during the transition */ 1120f8933667SMing Lei blk_mq_freeze_queue(lo->lo_queue); 1121f8933667SMing Lei 11221da177e4SLinus Torvalds spin_lock_irq(&lo->lo_lock); 11231da177e4SLinus Torvalds lo->lo_backing_file = NULL; 112405eb0f25SKay Sievers spin_unlock_irq(&lo->lo_lock); 11251da177e4SLinus Torvalds 11261da177e4SLinus Torvalds loop_release_xfer(lo); 11271da177e4SLinus Torvalds lo->transfer = NULL; 11281da177e4SLinus Torvalds lo->ioctl = NULL; 11291da177e4SLinus Torvalds lo->lo_device = NULL; 11301da177e4SLinus Torvalds lo->lo_encryption = NULL; 11311da177e4SLinus Torvalds lo->lo_offset = 0; 11321da177e4SLinus Torvalds lo->lo_sizelimit = 0; 11331da177e4SLinus Torvalds lo->lo_encrypt_key_size = 0; 11341da177e4SLinus Torvalds memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); 11351da177e4SLinus Torvalds memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); 11361da177e4SLinus Torvalds memset(lo->lo_file_name, 0, LO_NAME_SIZE); 113789e4fdecSOmar Sandoval blk_queue_logical_block_size(lo->lo_queue, 512); 1138bf093753SOmar Sandoval blk_queue_physical_block_size(lo->lo_queue, 512); 1139bf093753SOmar Sandoval blk_queue_io_min(lo->lo_queue, 512); 1140c1681bf8SAnatol Pomozov if (bdev) { 1141c1681bf8SAnatol Pomozov bdput(bdev); 1142f98393a6SPeter Zijlstra invalidate_bdev(bdev); 1143eedffa28SJeff Layton bdev->bd_inode->i_mapping->wb_err = 0; 1144c1681bf8SAnatol Pomozov } 114573285082SKen Chen set_capacity(lo->lo_disk, 0); 114651a0bb0cSMilan Broz loop_sysfs_exit(lo); 1147c3473c63SDavid Zeuthen if (bdev) { 11481da177e4SLinus Torvalds bd_set_size(bdev, 0); 1149c3473c63SDavid Zeuthen /* let user-space know about this change */ 1150c3473c63SDavid Zeuthen kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); 1151c3473c63SDavid Zeuthen } 11521da177e4SLinus Torvalds mapping_set_gfp_mask(filp->f_mapping, gfp); 11531da177e4SLinus Torvalds /* This is safe: open() is still holding a reference. */ 11541da177e4SLinus Torvalds module_put(THIS_MODULE); 1155f8933667SMing Lei blk_mq_unfreeze_queue(lo->lo_queue); 1156f8933667SMing Lei 11570da03cabSJan Kara partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev; 11580da03cabSJan Kara lo_number = lo->lo_number; 11590da03cabSJan Kara loop_unprepare_queue(lo); 11600da03cabSJan Kara out_unlock: 11610da03cabSJan Kara mutex_unlock(&loop_ctl_mutex); 11620da03cabSJan Kara if (partscan) { 1163d57f3374SJan Kara /* 1164d57f3374SJan Kara * bd_mutex has been held already in release path, so don't 1165d57f3374SJan Kara * acquire it if this function is called in such case. 1166d57f3374SJan Kara * 1167d57f3374SJan Kara * If the reread partition isn't from release path, lo_refcnt 1168d57f3374SJan Kara * must be at least one and it can only become zero when the 1169d57f3374SJan Kara * current holder is released. 1170d57f3374SJan Kara */ 1171f0b870dfSChristoph Hellwig if (!release) 1172f0b870dfSChristoph Hellwig mutex_lock(&bdev->bd_mutex); 1173f0b870dfSChristoph Hellwig err = bdev_disk_changed(bdev, false); 1174f0b870dfSChristoph Hellwig if (!release) 1175f0b870dfSChristoph Hellwig mutex_unlock(&bdev->bd_mutex); 117640853d6fSDongli Zhang if (err) 1177d57f3374SJan Kara pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", 11780da03cabSJan Kara __func__, lo_number, err); 1179d57f3374SJan Kara /* Device is gone, no point in returning error */ 1180d57f3374SJan Kara err = 0; 1181d57f3374SJan Kara } 1182758a58d0SDongli Zhang 1183758a58d0SDongli Zhang /* 1184758a58d0SDongli Zhang * lo->lo_state is set to Lo_unbound here after above partscan has 1185758a58d0SDongli Zhang * finished. 1186758a58d0SDongli Zhang * 1187758a58d0SDongli Zhang * There cannot be anybody else entering __loop_clr_fd() as 1188758a58d0SDongli Zhang * lo->lo_backing_file is already cleared and Lo_rundown state 1189758a58d0SDongli Zhang * protects us from all the other places trying to change the 'lo' 1190758a58d0SDongli Zhang * device. 1191758a58d0SDongli Zhang */ 1192758a58d0SDongli Zhang mutex_lock(&loop_ctl_mutex); 1193758a58d0SDongli Zhang lo->lo_flags = 0; 1194758a58d0SDongli Zhang if (!part_shift) 1195758a58d0SDongli Zhang lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; 1196758a58d0SDongli Zhang lo->lo_state = Lo_unbound; 1197758a58d0SDongli Zhang mutex_unlock(&loop_ctl_mutex); 1198758a58d0SDongli Zhang 1199f028f3b2SNikanth Karthikesan /* 1200310ca162STetsuo Handa * Need not hold loop_ctl_mutex to fput backing file. 1201310ca162STetsuo Handa * Calling fput holding loop_ctl_mutex triggers a circular 1202f028f3b2SNikanth Karthikesan * lock dependency possibility warning as fput can take 1203310ca162STetsuo Handa * bd_mutex which is usually taken before loop_ctl_mutex. 1204f028f3b2SNikanth Karthikesan */ 12057ccd0791SJan Kara if (filp) 1206f028f3b2SNikanth Karthikesan fput(filp); 12077ccd0791SJan Kara return err; 12081da177e4SLinus Torvalds } 12091da177e4SLinus Torvalds 1210a2505b79SJan Kara static int loop_clr_fd(struct loop_device *lo) 1211a2505b79SJan Kara { 12127ccd0791SJan Kara int err; 12137ccd0791SJan Kara 1214c28445faSJan Kara err = mutex_lock_killable(&loop_ctl_mutex); 12157ccd0791SJan Kara if (err) 12167ccd0791SJan Kara return err; 12177ccd0791SJan Kara if (lo->lo_state != Lo_bound) { 12187ccd0791SJan Kara mutex_unlock(&loop_ctl_mutex); 1219a2505b79SJan Kara return -ENXIO; 12207ccd0791SJan Kara } 1221a2505b79SJan Kara /* 1222a2505b79SJan Kara * If we've explicitly asked to tear down the loop device, 1223a2505b79SJan Kara * and it has an elevated reference count, set it for auto-teardown when 1224a2505b79SJan Kara * the last reference goes away. This stops $!~#$@ udev from 1225a2505b79SJan Kara * preventing teardown because it decided that it needs to run blkid on 1226a2505b79SJan Kara * the loopback device whenever they appear. xfstests is notorious for 1227a2505b79SJan Kara * failing tests because blkid via udev races with a losetup 1228a2505b79SJan Kara * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d 1229a2505b79SJan Kara * command to fail with EBUSY. 1230a2505b79SJan Kara */ 1231a2505b79SJan Kara if (atomic_read(&lo->lo_refcnt) > 1) { 1232a2505b79SJan Kara lo->lo_flags |= LO_FLAGS_AUTOCLEAR; 1233a2505b79SJan Kara mutex_unlock(&loop_ctl_mutex); 1234a2505b79SJan Kara return 0; 1235a2505b79SJan Kara } 1236a2505b79SJan Kara lo->lo_state = Lo_rundown; 12377ccd0791SJan Kara mutex_unlock(&loop_ctl_mutex); 1238a2505b79SJan Kara 12390da03cabSJan Kara return __loop_clr_fd(lo, false); 1240a2505b79SJan Kara } 1241a2505b79SJan Kara 12421da177e4SLinus Torvalds static int 12431da177e4SLinus Torvalds loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 12441da177e4SLinus Torvalds { 12451da177e4SLinus Torvalds int err; 12461da177e4SLinus Torvalds struct loop_func_table *xfer; 1247e4849737SEric W. Biederman kuid_t uid = current_uid(); 124885b0a54aSJan Kara struct block_device *bdev; 124985b0a54aSJan Kara bool partscan = false; 12501da177e4SLinus Torvalds 1251c28445faSJan Kara err = mutex_lock_killable(&loop_ctl_mutex); 1252550df5fdSJan Kara if (err) 1253550df5fdSJan Kara return err; 1254b0fafa81SDavid Howells if (lo->lo_encrypt_key_size && 1255e4849737SEric W. Biederman !uid_eq(lo->lo_key_owner, uid) && 1256550df5fdSJan Kara !capable(CAP_SYS_ADMIN)) { 1257550df5fdSJan Kara err = -EPERM; 1258550df5fdSJan Kara goto out_unlock; 1259550df5fdSJan Kara } 1260550df5fdSJan Kara if (lo->lo_state != Lo_bound) { 1261550df5fdSJan Kara err = -ENXIO; 1262550df5fdSJan Kara goto out_unlock; 1263550df5fdSJan Kara } 1264550df5fdSJan Kara if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) { 1265550df5fdSJan Kara err = -EINVAL; 1266550df5fdSJan Kara goto out_unlock; 1267550df5fdSJan Kara } 12681da177e4SLinus Torvalds 12695db470e2SJaegeuk Kim if (lo->lo_offset != info->lo_offset || 12705db470e2SJaegeuk Kim lo->lo_sizelimit != info->lo_sizelimit) { 12715db470e2SJaegeuk Kim sync_blockdev(lo->lo_device); 12725db470e2SJaegeuk Kim kill_bdev(lo->lo_device); 12735db470e2SJaegeuk Kim } 12745db470e2SJaegeuk Kim 1275ecdd0959SMing Lei /* I/O need to be drained during transfer transition */ 1276ecdd0959SMing Lei blk_mq_freeze_queue(lo->lo_queue); 1277ecdd0959SMing Lei 12781da177e4SLinus Torvalds err = loop_release_xfer(lo); 12791da177e4SLinus Torvalds if (err) 1280550df5fdSJan Kara goto out_unfreeze; 12811da177e4SLinus Torvalds 12821da177e4SLinus Torvalds if (info->lo_encrypt_type) { 12831da177e4SLinus Torvalds unsigned int type = info->lo_encrypt_type; 12841da177e4SLinus Torvalds 12851e047eaaSTetsuo Handa if (type >= MAX_LO_CRYPT) { 12861e047eaaSTetsuo Handa err = -EINVAL; 1287550df5fdSJan Kara goto out_unfreeze; 12881e047eaaSTetsuo Handa } 12891da177e4SLinus Torvalds xfer = xfer_funcs[type]; 12901e047eaaSTetsuo Handa if (xfer == NULL) { 12911e047eaaSTetsuo Handa err = -EINVAL; 1292550df5fdSJan Kara goto out_unfreeze; 12931e047eaaSTetsuo Handa } 12941da177e4SLinus Torvalds } else 12951da177e4SLinus Torvalds xfer = NULL; 12961da177e4SLinus Torvalds 12971da177e4SLinus Torvalds err = loop_init_xfer(lo, xfer, info); 12981da177e4SLinus Torvalds if (err) 1299550df5fdSJan Kara goto out_unfreeze; 13001da177e4SLinus Torvalds 13011da177e4SLinus Torvalds if (lo->lo_offset != info->lo_offset || 13021e6ec9eaSOmar Sandoval lo->lo_sizelimit != info->lo_sizelimit) { 13035db470e2SJaegeuk Kim /* kill_bdev should have truncated all the pages */ 13045db470e2SJaegeuk Kim if (lo->lo_device->bd_inode->i_mapping->nrpages) { 13055db470e2SJaegeuk Kim err = -EAGAIN; 13065db470e2SJaegeuk Kim pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", 13075db470e2SJaegeuk Kim __func__, lo->lo_number, lo->lo_file_name, 13085db470e2SJaegeuk Kim lo->lo_device->bd_inode->i_mapping->nrpages); 13095db470e2SJaegeuk Kim goto out_unfreeze; 13105db470e2SJaegeuk Kim } 13111e6ec9eaSOmar Sandoval if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) { 1312ecdd0959SMing Lei err = -EFBIG; 1313550df5fdSJan Kara goto out_unfreeze; 1314ecdd0959SMing Lei } 1315b040ad9cSArnd Bergmann } 1316541c742aSGuo Chao 1317dfaa2ef6SLukas Czerner loop_config_discard(lo); 13181da177e4SLinus Torvalds 13191da177e4SLinus Torvalds memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); 13201da177e4SLinus Torvalds memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); 13211da177e4SLinus Torvalds lo->lo_file_name[LO_NAME_SIZE-1] = 0; 13221da177e4SLinus Torvalds lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; 13231da177e4SLinus Torvalds 13241da177e4SLinus Torvalds if (!xfer) 13251da177e4SLinus Torvalds xfer = &none_funcs; 13261da177e4SLinus Torvalds lo->transfer = xfer->transfer; 13271da177e4SLinus Torvalds lo->ioctl = xfer->ioctl; 13281da177e4SLinus Torvalds 132996c58655SDavid Woodhouse if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != 133096c58655SDavid Woodhouse (info->lo_flags & LO_FLAGS_AUTOCLEAR)) 133196c58655SDavid Woodhouse lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; 133296c58655SDavid Woodhouse 13331da177e4SLinus Torvalds lo->lo_encrypt_key_size = info->lo_encrypt_key_size; 13341da177e4SLinus Torvalds lo->lo_init[0] = info->lo_init[0]; 13351da177e4SLinus Torvalds lo->lo_init[1] = info->lo_init[1]; 13361da177e4SLinus Torvalds if (info->lo_encrypt_key_size) { 13371da177e4SLinus Torvalds memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, 13381da177e4SLinus Torvalds info->lo_encrypt_key_size); 1339b0fafa81SDavid Howells lo->lo_key_owner = uid; 13401da177e4SLinus Torvalds } 13411da177e4SLinus Torvalds 13422e5ab5f3SMing Lei /* update dio if lo_offset or transfer is changed */ 13432e5ab5f3SMing Lei __loop_update_dio(lo, lo->use_dio); 13442e5ab5f3SMing Lei 1345550df5fdSJan Kara out_unfreeze: 1346ecdd0959SMing Lei blk_mq_unfreeze_queue(lo->lo_queue); 1347e02898b4SOmar Sandoval 1348e02898b4SOmar Sandoval if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) && 1349e02898b4SOmar Sandoval !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { 1350e02898b4SOmar Sandoval lo->lo_flags |= LO_FLAGS_PARTSCAN; 1351e02898b4SOmar Sandoval lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; 135285b0a54aSJan Kara bdev = lo->lo_device; 135385b0a54aSJan Kara partscan = true; 1354e02898b4SOmar Sandoval } 1355550df5fdSJan Kara out_unlock: 1356550df5fdSJan Kara mutex_unlock(&loop_ctl_mutex); 135785b0a54aSJan Kara if (partscan) 135885b0a54aSJan Kara loop_reread_partitions(lo, bdev); 1359e02898b4SOmar Sandoval 1360ecdd0959SMing Lei return err; 13611da177e4SLinus Torvalds } 13621da177e4SLinus Torvalds 13631da177e4SLinus Torvalds static int 13641da177e4SLinus Torvalds loop_get_status(struct loop_device *lo, struct loop_info64 *info) 13651da177e4SLinus Torvalds { 1366b1ab5fa3STetsuo Handa struct path path; 13671da177e4SLinus Torvalds struct kstat stat; 13682d1d4c1eSOmar Sandoval int ret; 13691da177e4SLinus Torvalds 1370c28445faSJan Kara ret = mutex_lock_killable(&loop_ctl_mutex); 13714a5ce9baSJan Kara if (ret) 13724a5ce9baSJan Kara return ret; 13732d1d4c1eSOmar Sandoval if (lo->lo_state != Lo_bound) { 1374310ca162STetsuo Handa mutex_unlock(&loop_ctl_mutex); 13751da177e4SLinus Torvalds return -ENXIO; 13762d1d4c1eSOmar Sandoval } 13772d1d4c1eSOmar Sandoval 13781da177e4SLinus Torvalds memset(info, 0, sizeof(*info)); 13791da177e4SLinus Torvalds info->lo_number = lo->lo_number; 13801da177e4SLinus Torvalds info->lo_offset = lo->lo_offset; 13811da177e4SLinus Torvalds info->lo_sizelimit = lo->lo_sizelimit; 13821da177e4SLinus Torvalds info->lo_flags = lo->lo_flags; 13831da177e4SLinus Torvalds memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); 13841da177e4SLinus Torvalds memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); 13851da177e4SLinus Torvalds info->lo_encrypt_type = 13861da177e4SLinus Torvalds lo->lo_encryption ? lo->lo_encryption->number : 0; 13871da177e4SLinus Torvalds if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { 13881da177e4SLinus Torvalds info->lo_encrypt_key_size = lo->lo_encrypt_key_size; 13891da177e4SLinus Torvalds memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, 13901da177e4SLinus Torvalds lo->lo_encrypt_key_size); 13911da177e4SLinus Torvalds } 13922d1d4c1eSOmar Sandoval 1393310ca162STetsuo Handa /* Drop loop_ctl_mutex while we call into the filesystem. */ 1394b1ab5fa3STetsuo Handa path = lo->lo_backing_file->f_path; 1395b1ab5fa3STetsuo Handa path_get(&path); 1396310ca162STetsuo Handa mutex_unlock(&loop_ctl_mutex); 1397b1ab5fa3STetsuo Handa ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT); 13982d1d4c1eSOmar Sandoval if (!ret) { 13992d1d4c1eSOmar Sandoval info->lo_device = huge_encode_dev(stat.dev); 14002d1d4c1eSOmar Sandoval info->lo_inode = stat.ino; 14012d1d4c1eSOmar Sandoval info->lo_rdevice = huge_encode_dev(stat.rdev); 14022d1d4c1eSOmar Sandoval } 1403b1ab5fa3STetsuo Handa path_put(&path); 14042d1d4c1eSOmar Sandoval return ret; 14051da177e4SLinus Torvalds } 14061da177e4SLinus Torvalds 14071da177e4SLinus Torvalds static void 14081da177e4SLinus Torvalds loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) 14091da177e4SLinus Torvalds { 14101da177e4SLinus Torvalds memset(info64, 0, sizeof(*info64)); 14111da177e4SLinus Torvalds info64->lo_number = info->lo_number; 14121da177e4SLinus Torvalds info64->lo_device = info->lo_device; 14131da177e4SLinus Torvalds info64->lo_inode = info->lo_inode; 14141da177e4SLinus Torvalds info64->lo_rdevice = info->lo_rdevice; 14151da177e4SLinus Torvalds info64->lo_offset = info->lo_offset; 14161da177e4SLinus Torvalds info64->lo_sizelimit = 0; 14171da177e4SLinus Torvalds info64->lo_encrypt_type = info->lo_encrypt_type; 14181da177e4SLinus Torvalds info64->lo_encrypt_key_size = info->lo_encrypt_key_size; 14191da177e4SLinus Torvalds info64->lo_flags = info->lo_flags; 14201da177e4SLinus Torvalds info64->lo_init[0] = info->lo_init[0]; 14211da177e4SLinus Torvalds info64->lo_init[1] = info->lo_init[1]; 14221da177e4SLinus Torvalds if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) 14231da177e4SLinus Torvalds memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); 14241da177e4SLinus Torvalds else 14251da177e4SLinus Torvalds memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); 14261da177e4SLinus Torvalds memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); 14271da177e4SLinus Torvalds } 14281da177e4SLinus Torvalds 14291da177e4SLinus Torvalds static int 14301da177e4SLinus Torvalds loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) 14311da177e4SLinus Torvalds { 14321da177e4SLinus Torvalds memset(info, 0, sizeof(*info)); 14331da177e4SLinus Torvalds info->lo_number = info64->lo_number; 14341da177e4SLinus Torvalds info->lo_device = info64->lo_device; 14351da177e4SLinus Torvalds info->lo_inode = info64->lo_inode; 14361da177e4SLinus Torvalds info->lo_rdevice = info64->lo_rdevice; 14371da177e4SLinus Torvalds info->lo_offset = info64->lo_offset; 14381da177e4SLinus Torvalds info->lo_encrypt_type = info64->lo_encrypt_type; 14391da177e4SLinus Torvalds info->lo_encrypt_key_size = info64->lo_encrypt_key_size; 14401da177e4SLinus Torvalds info->lo_flags = info64->lo_flags; 14411da177e4SLinus Torvalds info->lo_init[0] = info64->lo_init[0]; 14421da177e4SLinus Torvalds info->lo_init[1] = info64->lo_init[1]; 14431da177e4SLinus Torvalds if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) 14441da177e4SLinus Torvalds memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); 14451da177e4SLinus Torvalds else 14461da177e4SLinus Torvalds memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); 14471da177e4SLinus Torvalds memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); 14481da177e4SLinus Torvalds 14491da177e4SLinus Torvalds /* error in case values were truncated */ 14501da177e4SLinus Torvalds if (info->lo_device != info64->lo_device || 14511da177e4SLinus Torvalds info->lo_rdevice != info64->lo_rdevice || 14521da177e4SLinus Torvalds info->lo_inode != info64->lo_inode || 14531da177e4SLinus Torvalds info->lo_offset != info64->lo_offset) 14541da177e4SLinus Torvalds return -EOVERFLOW; 14551da177e4SLinus Torvalds 14561da177e4SLinus Torvalds return 0; 14571da177e4SLinus Torvalds } 14581da177e4SLinus Torvalds 14591da177e4SLinus Torvalds static int 14601da177e4SLinus Torvalds loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) 14611da177e4SLinus Torvalds { 14621da177e4SLinus Torvalds struct loop_info info; 14631da177e4SLinus Torvalds struct loop_info64 info64; 14641da177e4SLinus Torvalds 14651da177e4SLinus Torvalds if (copy_from_user(&info, arg, sizeof (struct loop_info))) 14661da177e4SLinus Torvalds return -EFAULT; 14671da177e4SLinus Torvalds loop_info64_from_old(&info, &info64); 14681da177e4SLinus Torvalds return loop_set_status(lo, &info64); 14691da177e4SLinus Torvalds } 14701da177e4SLinus Torvalds 14711da177e4SLinus Torvalds static int 14721da177e4SLinus Torvalds loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) 14731da177e4SLinus Torvalds { 14741da177e4SLinus Torvalds struct loop_info64 info64; 14751da177e4SLinus Torvalds 14761da177e4SLinus Torvalds if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) 14771da177e4SLinus Torvalds return -EFAULT; 14781da177e4SLinus Torvalds return loop_set_status(lo, &info64); 14791da177e4SLinus Torvalds } 14801da177e4SLinus Torvalds 14811da177e4SLinus Torvalds static int 14821da177e4SLinus Torvalds loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { 14831da177e4SLinus Torvalds struct loop_info info; 14841da177e4SLinus Torvalds struct loop_info64 info64; 1485bdac616dSOmar Sandoval int err; 14861da177e4SLinus Torvalds 14874a5ce9baSJan Kara if (!arg) 1488bdac616dSOmar Sandoval return -EINVAL; 14891da177e4SLinus Torvalds err = loop_get_status(lo, &info64); 14901da177e4SLinus Torvalds if (!err) 14911da177e4SLinus Torvalds err = loop_info64_to_old(&info64, &info); 14921da177e4SLinus Torvalds if (!err && copy_to_user(arg, &info, sizeof(info))) 14931da177e4SLinus Torvalds err = -EFAULT; 14941da177e4SLinus Torvalds 14951da177e4SLinus Torvalds return err; 14961da177e4SLinus Torvalds } 14971da177e4SLinus Torvalds 14981da177e4SLinus Torvalds static int 14991da177e4SLinus Torvalds loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { 15001da177e4SLinus Torvalds struct loop_info64 info64; 1501bdac616dSOmar Sandoval int err; 15021da177e4SLinus Torvalds 15034a5ce9baSJan Kara if (!arg) 1504bdac616dSOmar Sandoval return -EINVAL; 15051da177e4SLinus Torvalds err = loop_get_status(lo, &info64); 15061da177e4SLinus Torvalds if (!err && copy_to_user(arg, &info64, sizeof(info64))) 15071da177e4SLinus Torvalds err = -EFAULT; 15081da177e4SLinus Torvalds 15091da177e4SLinus Torvalds return err; 15101da177e4SLinus Torvalds } 15111da177e4SLinus Torvalds 151251001b7dSHannes Reinecke static int loop_set_capacity(struct loop_device *lo) 151353d66608SJ. R. Okajima { 151453d66608SJ. R. Okajima if (unlikely(lo->lo_state != Lo_bound)) 15157b0576a3SGuo Chao return -ENXIO; 151653d66608SJ. R. Okajima 15171e6ec9eaSOmar Sandoval return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); 151853d66608SJ. R. Okajima } 151953d66608SJ. R. Okajima 1520ab1cb278SMing Lei static int loop_set_dio(struct loop_device *lo, unsigned long arg) 1521ab1cb278SMing Lei { 1522ab1cb278SMing Lei int error = -ENXIO; 1523ab1cb278SMing Lei if (lo->lo_state != Lo_bound) 1524ab1cb278SMing Lei goto out; 1525ab1cb278SMing Lei 1526ab1cb278SMing Lei __loop_update_dio(lo, !!arg); 1527ab1cb278SMing Lei if (lo->use_dio == !!arg) 1528ab1cb278SMing Lei return 0; 1529ab1cb278SMing Lei error = -EINVAL; 1530ab1cb278SMing Lei out: 1531ab1cb278SMing Lei return error; 1532ab1cb278SMing Lei } 1533ab1cb278SMing Lei 153489e4fdecSOmar Sandoval static int loop_set_block_size(struct loop_device *lo, unsigned long arg) 153589e4fdecSOmar Sandoval { 15365db470e2SJaegeuk Kim int err = 0; 15375db470e2SJaegeuk Kim 153889e4fdecSOmar Sandoval if (lo->lo_state != Lo_bound) 153989e4fdecSOmar Sandoval return -ENXIO; 154089e4fdecSOmar Sandoval 154189e4fdecSOmar Sandoval if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg)) 154289e4fdecSOmar Sandoval return -EINVAL; 154389e4fdecSOmar Sandoval 15447e81f99aSMartijn Coenen if (lo->lo_queue->limits.logical_block_size == arg) 15457e81f99aSMartijn Coenen return 0; 15467e81f99aSMartijn Coenen 15475db470e2SJaegeuk Kim sync_blockdev(lo->lo_device); 15485db470e2SJaegeuk Kim kill_bdev(lo->lo_device); 15495db470e2SJaegeuk Kim 155089e4fdecSOmar Sandoval blk_mq_freeze_queue(lo->lo_queue); 155189e4fdecSOmar Sandoval 15525db470e2SJaegeuk Kim /* kill_bdev should have truncated all the pages */ 15537e81f99aSMartijn Coenen if (lo->lo_device->bd_inode->i_mapping->nrpages) { 15545db470e2SJaegeuk Kim err = -EAGAIN; 15555db470e2SJaegeuk Kim pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", 15565db470e2SJaegeuk Kim __func__, lo->lo_number, lo->lo_file_name, 15575db470e2SJaegeuk Kim lo->lo_device->bd_inode->i_mapping->nrpages); 15585db470e2SJaegeuk Kim goto out_unfreeze; 15595db470e2SJaegeuk Kim } 15605db470e2SJaegeuk Kim 156189e4fdecSOmar Sandoval blk_queue_logical_block_size(lo->lo_queue, arg); 1562bf093753SOmar Sandoval blk_queue_physical_block_size(lo->lo_queue, arg); 1563bf093753SOmar Sandoval blk_queue_io_min(lo->lo_queue, arg); 156489e4fdecSOmar Sandoval loop_update_dio(lo); 15655db470e2SJaegeuk Kim out_unfreeze: 156689e4fdecSOmar Sandoval blk_mq_unfreeze_queue(lo->lo_queue); 156789e4fdecSOmar Sandoval 15685db470e2SJaegeuk Kim return err; 156989e4fdecSOmar Sandoval } 157089e4fdecSOmar Sandoval 1571a1316544SJan Kara static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd, 1572a1316544SJan Kara unsigned long arg) 15731da177e4SLinus Torvalds { 15741da177e4SLinus Torvalds int err; 15751da177e4SLinus Torvalds 1576c28445faSJan Kara err = mutex_lock_killable(&loop_ctl_mutex); 15773148ffbdSOmar Sandoval if (err) 1578a1316544SJan Kara return err; 15791da177e4SLinus Torvalds switch (cmd) { 158053d66608SJ. R. Okajima case LOOP_SET_CAPACITY: 158151001b7dSHannes Reinecke err = loop_set_capacity(lo); 158253d66608SJ. R. Okajima break; 1583ab1cb278SMing Lei case LOOP_SET_DIRECT_IO: 1584ab1cb278SMing Lei err = loop_set_dio(lo, arg); 1585ab1cb278SMing Lei break; 158689e4fdecSOmar Sandoval case LOOP_SET_BLOCK_SIZE: 158789e4fdecSOmar Sandoval err = loop_set_block_size(lo, arg); 158889e4fdecSOmar Sandoval break; 15891da177e4SLinus Torvalds default: 15901da177e4SLinus Torvalds err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; 15911da177e4SLinus Torvalds } 1592310ca162STetsuo Handa mutex_unlock(&loop_ctl_mutex); 1593a1316544SJan Kara return err; 1594a1316544SJan Kara } 1595f028f3b2SNikanth Karthikesan 1596a1316544SJan Kara static int lo_ioctl(struct block_device *bdev, fmode_t mode, 1597a1316544SJan Kara unsigned int cmd, unsigned long arg) 1598a1316544SJan Kara { 1599a1316544SJan Kara struct loop_device *lo = bdev->bd_disk->private_data; 1600a1316544SJan Kara int err; 1601a1316544SJan Kara 1602a1316544SJan Kara switch (cmd) { 1603a1316544SJan Kara case LOOP_SET_FD: 1604757ecf40SJan Kara return loop_set_fd(lo, mode, bdev, arg); 1605a1316544SJan Kara case LOOP_CHANGE_FD: 1606c3710770SJan Kara return loop_change_fd(lo, bdev, arg); 1607a1316544SJan Kara case LOOP_CLR_FD: 16087ccd0791SJan Kara return loop_clr_fd(lo); 1609a1316544SJan Kara case LOOP_SET_STATUS: 1610a1316544SJan Kara err = -EPERM; 1611a1316544SJan Kara if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { 1612a1316544SJan Kara err = loop_set_status_old(lo, 1613a1316544SJan Kara (struct loop_info __user *)arg); 1614a1316544SJan Kara } 1615a1316544SJan Kara break; 1616a1316544SJan Kara case LOOP_GET_STATUS: 16174a5ce9baSJan Kara return loop_get_status_old(lo, (struct loop_info __user *) arg); 1618a1316544SJan Kara case LOOP_SET_STATUS64: 1619a1316544SJan Kara err = -EPERM; 1620a1316544SJan Kara if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { 1621a1316544SJan Kara err = loop_set_status64(lo, 1622a1316544SJan Kara (struct loop_info64 __user *) arg); 1623a1316544SJan Kara } 1624a1316544SJan Kara break; 1625a1316544SJan Kara case LOOP_GET_STATUS64: 16264a5ce9baSJan Kara return loop_get_status64(lo, (struct loop_info64 __user *) arg); 1627a1316544SJan Kara case LOOP_SET_CAPACITY: 1628a1316544SJan Kara case LOOP_SET_DIRECT_IO: 1629a1316544SJan Kara case LOOP_SET_BLOCK_SIZE: 1630a1316544SJan Kara if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN)) 1631a1316544SJan Kara return -EPERM; 1632a1316544SJan Kara /* Fall through */ 1633a1316544SJan Kara default: 1634a1316544SJan Kara err = lo_simple_ioctl(lo, cmd, arg); 1635a1316544SJan Kara break; 1636a1316544SJan Kara } 1637a1316544SJan Kara 16381da177e4SLinus Torvalds return err; 16391da177e4SLinus Torvalds } 16401da177e4SLinus Torvalds 1641863d5b82SDavid Howells #ifdef CONFIG_COMPAT 1642863d5b82SDavid Howells struct compat_loop_info { 1643863d5b82SDavid Howells compat_int_t lo_number; /* ioctl r/o */ 1644863d5b82SDavid Howells compat_dev_t lo_device; /* ioctl r/o */ 1645863d5b82SDavid Howells compat_ulong_t lo_inode; /* ioctl r/o */ 1646863d5b82SDavid Howells compat_dev_t lo_rdevice; /* ioctl r/o */ 1647863d5b82SDavid Howells compat_int_t lo_offset; 1648863d5b82SDavid Howells compat_int_t lo_encrypt_type; 1649863d5b82SDavid Howells compat_int_t lo_encrypt_key_size; /* ioctl w/o */ 1650863d5b82SDavid Howells compat_int_t lo_flags; /* ioctl r/o */ 1651863d5b82SDavid Howells char lo_name[LO_NAME_SIZE]; 1652863d5b82SDavid Howells unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ 1653863d5b82SDavid Howells compat_ulong_t lo_init[2]; 1654863d5b82SDavid Howells char reserved[4]; 1655863d5b82SDavid Howells }; 1656863d5b82SDavid Howells 1657863d5b82SDavid Howells /* 1658863d5b82SDavid Howells * Transfer 32-bit compatibility structure in userspace to 64-bit loop info 1659863d5b82SDavid Howells * - noinlined to reduce stack space usage in main part of driver 1660863d5b82SDavid Howells */ 1661863d5b82SDavid Howells static noinline int 1662ba674cfcSAl Viro loop_info64_from_compat(const struct compat_loop_info __user *arg, 1663863d5b82SDavid Howells struct loop_info64 *info64) 1664863d5b82SDavid Howells { 1665863d5b82SDavid Howells struct compat_loop_info info; 1666863d5b82SDavid Howells 1667863d5b82SDavid Howells if (copy_from_user(&info, arg, sizeof(info))) 1668863d5b82SDavid Howells return -EFAULT; 1669863d5b82SDavid Howells 1670863d5b82SDavid Howells memset(info64, 0, sizeof(*info64)); 1671863d5b82SDavid Howells info64->lo_number = info.lo_number; 1672863d5b82SDavid Howells info64->lo_device = info.lo_device; 1673863d5b82SDavid Howells info64->lo_inode = info.lo_inode; 1674863d5b82SDavid Howells info64->lo_rdevice = info.lo_rdevice; 1675863d5b82SDavid Howells info64->lo_offset = info.lo_offset; 1676863d5b82SDavid Howells info64->lo_sizelimit = 0; 1677863d5b82SDavid Howells info64->lo_encrypt_type = info.lo_encrypt_type; 1678863d5b82SDavid Howells info64->lo_encrypt_key_size = info.lo_encrypt_key_size; 1679863d5b82SDavid Howells info64->lo_flags = info.lo_flags; 1680863d5b82SDavid Howells info64->lo_init[0] = info.lo_init[0]; 1681863d5b82SDavid Howells info64->lo_init[1] = info.lo_init[1]; 1682863d5b82SDavid Howells if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) 1683863d5b82SDavid Howells memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE); 1684863d5b82SDavid Howells else 1685863d5b82SDavid Howells memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE); 1686863d5b82SDavid Howells memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE); 1687863d5b82SDavid Howells return 0; 1688863d5b82SDavid Howells } 1689863d5b82SDavid Howells 1690863d5b82SDavid Howells /* 1691863d5b82SDavid Howells * Transfer 64-bit loop info to 32-bit compatibility structure in userspace 1692863d5b82SDavid Howells * - noinlined to reduce stack space usage in main part of driver 1693863d5b82SDavid Howells */ 1694863d5b82SDavid Howells static noinline int 1695863d5b82SDavid Howells loop_info64_to_compat(const struct loop_info64 *info64, 1696863d5b82SDavid Howells struct compat_loop_info __user *arg) 1697863d5b82SDavid Howells { 1698863d5b82SDavid Howells struct compat_loop_info info; 1699863d5b82SDavid Howells 1700863d5b82SDavid Howells memset(&info, 0, sizeof(info)); 1701863d5b82SDavid Howells info.lo_number = info64->lo_number; 1702863d5b82SDavid Howells info.lo_device = info64->lo_device; 1703863d5b82SDavid Howells info.lo_inode = info64->lo_inode; 1704863d5b82SDavid Howells info.lo_rdevice = info64->lo_rdevice; 1705863d5b82SDavid Howells info.lo_offset = info64->lo_offset; 1706863d5b82SDavid Howells info.lo_encrypt_type = info64->lo_encrypt_type; 1707863d5b82SDavid Howells info.lo_encrypt_key_size = info64->lo_encrypt_key_size; 1708863d5b82SDavid Howells info.lo_flags = info64->lo_flags; 1709863d5b82SDavid Howells info.lo_init[0] = info64->lo_init[0]; 1710863d5b82SDavid Howells info.lo_init[1] = info64->lo_init[1]; 1711863d5b82SDavid Howells if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI) 1712863d5b82SDavid Howells memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE); 1713863d5b82SDavid Howells else 1714863d5b82SDavid Howells memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE); 1715863d5b82SDavid Howells memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); 1716863d5b82SDavid Howells 1717863d5b82SDavid Howells /* error in case values were truncated */ 1718863d5b82SDavid Howells if (info.lo_device != info64->lo_device || 1719863d5b82SDavid Howells info.lo_rdevice != info64->lo_rdevice || 1720863d5b82SDavid Howells info.lo_inode != info64->lo_inode || 1721863d5b82SDavid Howells info.lo_offset != info64->lo_offset || 1722863d5b82SDavid Howells info.lo_init[0] != info64->lo_init[0] || 1723863d5b82SDavid Howells info.lo_init[1] != info64->lo_init[1]) 1724863d5b82SDavid Howells return -EOVERFLOW; 1725863d5b82SDavid Howells 1726863d5b82SDavid Howells if (copy_to_user(arg, &info, sizeof(info))) 1727863d5b82SDavid Howells return -EFAULT; 1728863d5b82SDavid Howells return 0; 1729863d5b82SDavid Howells } 1730863d5b82SDavid Howells 1731863d5b82SDavid Howells static int 1732863d5b82SDavid Howells loop_set_status_compat(struct loop_device *lo, 1733863d5b82SDavid Howells const struct compat_loop_info __user *arg) 1734863d5b82SDavid Howells { 1735863d5b82SDavid Howells struct loop_info64 info64; 1736863d5b82SDavid Howells int ret; 1737863d5b82SDavid Howells 1738863d5b82SDavid Howells ret = loop_info64_from_compat(arg, &info64); 1739863d5b82SDavid Howells if (ret < 0) 1740863d5b82SDavid Howells return ret; 1741863d5b82SDavid Howells return loop_set_status(lo, &info64); 1742863d5b82SDavid Howells } 1743863d5b82SDavid Howells 1744863d5b82SDavid Howells static int 1745863d5b82SDavid Howells loop_get_status_compat(struct loop_device *lo, 1746863d5b82SDavid Howells struct compat_loop_info __user *arg) 1747863d5b82SDavid Howells { 1748863d5b82SDavid Howells struct loop_info64 info64; 1749bdac616dSOmar Sandoval int err; 1750863d5b82SDavid Howells 17514a5ce9baSJan Kara if (!arg) 1752bdac616dSOmar Sandoval return -EINVAL; 1753863d5b82SDavid Howells err = loop_get_status(lo, &info64); 1754863d5b82SDavid Howells if (!err) 1755863d5b82SDavid Howells err = loop_info64_to_compat(&info64, arg); 1756863d5b82SDavid Howells return err; 1757863d5b82SDavid Howells } 1758863d5b82SDavid Howells 1759bb214884SAl Viro static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, 1760bb214884SAl Viro unsigned int cmd, unsigned long arg) 1761863d5b82SDavid Howells { 1762bb214884SAl Viro struct loop_device *lo = bdev->bd_disk->private_data; 1763863d5b82SDavid Howells int err; 1764863d5b82SDavid Howells 1765863d5b82SDavid Howells switch(cmd) { 1766863d5b82SDavid Howells case LOOP_SET_STATUS: 17673148ffbdSOmar Sandoval err = loop_set_status_compat(lo, 17683148ffbdSOmar Sandoval (const struct compat_loop_info __user *)arg); 1769863d5b82SDavid Howells break; 1770863d5b82SDavid Howells case LOOP_GET_STATUS: 17713148ffbdSOmar Sandoval err = loop_get_status_compat(lo, 17723148ffbdSOmar Sandoval (struct compat_loop_info __user *)arg); 1773863d5b82SDavid Howells break; 177453d66608SJ. R. Okajima case LOOP_SET_CAPACITY: 1775863d5b82SDavid Howells case LOOP_CLR_FD: 1776863d5b82SDavid Howells case LOOP_GET_STATUS64: 1777863d5b82SDavid Howells case LOOP_SET_STATUS64: 1778863d5b82SDavid Howells arg = (unsigned long) compat_ptr(arg); 1779d893ff86SGustavo A. R. Silva /* fall through */ 1780863d5b82SDavid Howells case LOOP_SET_FD: 1781863d5b82SDavid Howells case LOOP_CHANGE_FD: 17829fea4b39SEvan Green case LOOP_SET_BLOCK_SIZE: 1783fdbe4eeeSAlessio Balsini case LOOP_SET_DIRECT_IO: 1784bb214884SAl Viro err = lo_ioctl(bdev, mode, cmd, arg); 1785863d5b82SDavid Howells break; 1786863d5b82SDavid Howells default: 1787863d5b82SDavid Howells err = -ENOIOCTLCMD; 1788863d5b82SDavid Howells break; 1789863d5b82SDavid Howells } 1790863d5b82SDavid Howells return err; 1791863d5b82SDavid Howells } 1792863d5b82SDavid Howells #endif 1793863d5b82SDavid Howells 1794bb214884SAl Viro static int lo_open(struct block_device *bdev, fmode_t mode) 17951da177e4SLinus Torvalds { 1796770fe30aSKay Sievers struct loop_device *lo; 17970a42e99bSJan Kara int err; 1798770fe30aSKay Sievers 17990a42e99bSJan Kara err = mutex_lock_killable(&loop_ctl_mutex); 18000a42e99bSJan Kara if (err) 18010a42e99bSJan Kara return err; 1802770fe30aSKay Sievers lo = bdev->bd_disk->private_data; 1803770fe30aSKay Sievers if (!lo) { 1804770fe30aSKay Sievers err = -ENXIO; 1805770fe30aSKay Sievers goto out; 1806770fe30aSKay Sievers } 18071da177e4SLinus Torvalds 1808f8933667SMing Lei atomic_inc(&lo->lo_refcnt); 1809770fe30aSKay Sievers out: 18100a42e99bSJan Kara mutex_unlock(&loop_ctl_mutex); 1811770fe30aSKay Sievers return err; 18121da177e4SLinus Torvalds } 18131da177e4SLinus Torvalds 1814967d1dc1SJan Kara static void lo_release(struct gendisk *disk, fmode_t mode) 18151da177e4SLinus Torvalds { 1816967d1dc1SJan Kara struct loop_device *lo; 18171da177e4SLinus Torvalds 18180a42e99bSJan Kara mutex_lock(&loop_ctl_mutex); 1819967d1dc1SJan Kara lo = disk->private_data; 1820f8933667SMing Lei if (atomic_dec_return(&lo->lo_refcnt)) 18210a42e99bSJan Kara goto out_unlock; 1822f8933667SMing Lei 182314f27939SMilan Broz if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { 1824a2505b79SJan Kara if (lo->lo_state != Lo_bound) 1825a2505b79SJan Kara goto out_unlock; 1826a2505b79SJan Kara lo->lo_state = Lo_rundown; 18277ccd0791SJan Kara mutex_unlock(&loop_ctl_mutex); 182814f27939SMilan Broz /* 182914f27939SMilan Broz * In autoclear mode, stop the loop thread 183014f27939SMilan Broz * and remove configuration after last close. 183114f27939SMilan Broz */ 18320da03cabSJan Kara __loop_clr_fd(lo, true); 18330a42e99bSJan Kara return; 183443cade80SOmar Sandoval } else if (lo->lo_state == Lo_bound) { 183514f27939SMilan Broz /* 183614f27939SMilan Broz * Otherwise keep thread (if running) and config, 183714f27939SMilan Broz * but flush possible ongoing bios in thread. 183814f27939SMilan Broz */ 183943cade80SOmar Sandoval blk_mq_freeze_queue(lo->lo_queue); 184043cade80SOmar Sandoval blk_mq_unfreeze_queue(lo->lo_queue); 184114f27939SMilan Broz } 184296c58655SDavid Woodhouse 18430a42e99bSJan Kara out_unlock: 1844310ca162STetsuo Handa mutex_unlock(&loop_ctl_mutex); 1845ae665016SLinus Torvalds } 1846ae665016SLinus Torvalds 184783d5cde4SAlexey Dobriyan static const struct block_device_operations lo_fops = { 18481da177e4SLinus Torvalds .owner = THIS_MODULE, 1849bb214884SAl Viro .open = lo_open, 1850bb214884SAl Viro .release = lo_release, 1851bb214884SAl Viro .ioctl = lo_ioctl, 1852863d5b82SDavid Howells #ifdef CONFIG_COMPAT 1853bb214884SAl Viro .compat_ioctl = lo_compat_ioctl, 1854863d5b82SDavid Howells #endif 18551da177e4SLinus Torvalds }; 18561da177e4SLinus Torvalds 18571da177e4SLinus Torvalds /* 18581da177e4SLinus Torvalds * And now the modules code and kernel interface. 18591da177e4SLinus Torvalds */ 186073285082SKen Chen static int max_loop; 18615657a819SJoe Perches module_param(max_loop, int, 0444); 1862a47653fcSKen Chen MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); 18635657a819SJoe Perches module_param(max_part, int, 0444); 1864476a4813SLaurent Vivier MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); 18651da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 18661da177e4SLinus Torvalds MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); 18671da177e4SLinus Torvalds 18681da177e4SLinus Torvalds int loop_register_transfer(struct loop_func_table *funcs) 18691da177e4SLinus Torvalds { 18701da177e4SLinus Torvalds unsigned int n = funcs->number; 18711da177e4SLinus Torvalds 18721da177e4SLinus Torvalds if (n >= MAX_LO_CRYPT || xfer_funcs[n]) 18731da177e4SLinus Torvalds return -EINVAL; 18741da177e4SLinus Torvalds xfer_funcs[n] = funcs; 18751da177e4SLinus Torvalds return 0; 18761da177e4SLinus Torvalds } 18771da177e4SLinus Torvalds 187834dd82afSKay Sievers static int unregister_transfer_cb(int id, void *ptr, void *data) 187934dd82afSKay Sievers { 188034dd82afSKay Sievers struct loop_device *lo = ptr; 188134dd82afSKay Sievers struct loop_func_table *xfer = data; 188234dd82afSKay Sievers 1883310ca162STetsuo Handa mutex_lock(&loop_ctl_mutex); 188434dd82afSKay Sievers if (lo->lo_encryption == xfer) 188534dd82afSKay Sievers loop_release_xfer(lo); 1886310ca162STetsuo Handa mutex_unlock(&loop_ctl_mutex); 188734dd82afSKay Sievers return 0; 188834dd82afSKay Sievers } 188934dd82afSKay Sievers 18901da177e4SLinus Torvalds int loop_unregister_transfer(int number) 18911da177e4SLinus Torvalds { 18921da177e4SLinus Torvalds unsigned int n = number; 18931da177e4SLinus Torvalds struct loop_func_table *xfer; 18941da177e4SLinus Torvalds 18951da177e4SLinus Torvalds if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) 18961da177e4SLinus Torvalds return -EINVAL; 18971da177e4SLinus Torvalds 18981da177e4SLinus Torvalds xfer_funcs[n] = NULL; 189934dd82afSKay Sievers idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer); 19001da177e4SLinus Torvalds return 0; 19011da177e4SLinus Torvalds } 19021da177e4SLinus Torvalds 19031da177e4SLinus Torvalds EXPORT_SYMBOL(loop_register_transfer); 19041da177e4SLinus Torvalds EXPORT_SYMBOL(loop_unregister_transfer); 19051da177e4SLinus Torvalds 1906fc17b653SChristoph Hellwig static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, 1907b5dd2f60SMing Lei const struct blk_mq_queue_data *bd) 1908b5dd2f60SMing Lei { 19091894e916SJens Axboe struct request *rq = bd->rq; 19101894e916SJens Axboe struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); 19111894e916SJens Axboe struct loop_device *lo = rq->q->queuedata; 1912b5dd2f60SMing Lei 19131894e916SJens Axboe blk_mq_start_request(rq); 1914b5dd2f60SMing Lei 1915f4aa4c7bSMing Lei if (lo->lo_state != Lo_bound) 1916fc17b653SChristoph Hellwig return BLK_STS_IOERR; 1917f4aa4c7bSMing Lei 19181894e916SJens Axboe switch (req_op(rq)) { 1919f0225cacSChristoph Hellwig case REQ_OP_FLUSH: 1920f0225cacSChristoph Hellwig case REQ_OP_DISCARD: 192119372e27SChristoph Hellwig case REQ_OP_WRITE_ZEROES: 1922bc07c10aSMing Lei cmd->use_aio = false; 1923f0225cacSChristoph Hellwig break; 1924f0225cacSChristoph Hellwig default: 1925f0225cacSChristoph Hellwig cmd->use_aio = lo->use_dio; 1926f0225cacSChristoph Hellwig break; 1927f0225cacSChristoph Hellwig } 1928bc07c10aSMing Lei 1929d4478e92SShaohua Li /* always use the first bio's css */ 19300b508bc9SShaohua Li #ifdef CONFIG_BLK_CGROUP 1931db6638d7SDennis Zhou if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { 1932db6638d7SDennis Zhou cmd->css = &bio_blkcg(rq->bio)->css; 1933d4478e92SShaohua Li css_get(cmd->css); 1934d4478e92SShaohua Li } else 1935d4478e92SShaohua Li #endif 1936d4478e92SShaohua Li cmd->css = NULL; 19373989144fSPetr Mladek kthread_queue_work(&lo->worker, &cmd->work); 1938b5dd2f60SMing Lei 1939fc17b653SChristoph Hellwig return BLK_STS_OK; 1940b5dd2f60SMing Lei } 1941b5dd2f60SMing Lei 1942b5dd2f60SMing Lei static void loop_handle_cmd(struct loop_cmd *cmd) 1943b5dd2f60SMing Lei { 19441894e916SJens Axboe struct request *rq = blk_mq_rq_from_pdu(cmd); 19451894e916SJens Axboe const bool write = op_is_write(req_op(rq)); 19461894e916SJens Axboe struct loop_device *lo = rq->q->queuedata; 1947f4829a9bSChristoph Hellwig int ret = 0; 1948b5dd2f60SMing Lei 1949f4829a9bSChristoph Hellwig if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { 1950f4829a9bSChristoph Hellwig ret = -EIO; 1951b5dd2f60SMing Lei goto failed; 1952f4829a9bSChristoph Hellwig } 1953b5dd2f60SMing Lei 19541894e916SJens Axboe ret = do_req_filebacked(lo, rq); 1955b5dd2f60SMing Lei failed: 1956bc07c10aSMing Lei /* complete non-aio request */ 1957fe2cb290SChristoph Hellwig if (!cmd->use_aio || ret) { 1958*8cd55087SEvan Green if (ret == -EOPNOTSUPP) 1959*8cd55087SEvan Green cmd->ret = ret; 1960*8cd55087SEvan Green else 1961fe2cb290SChristoph Hellwig cmd->ret = ret ? -EIO : 0; 19621894e916SJens Axboe blk_mq_complete_request(rq); 1963fe2cb290SChristoph Hellwig } 1964b5dd2f60SMing Lei } 1965b5dd2f60SMing Lei 1966e03a3d7aSMing Lei static void loop_queue_work(struct kthread_work *work) 1967b5dd2f60SMing Lei { 1968b5dd2f60SMing Lei struct loop_cmd *cmd = 1969e03a3d7aSMing Lei container_of(work, struct loop_cmd, work); 1970b5dd2f60SMing Lei 1971b5dd2f60SMing Lei loop_handle_cmd(cmd); 1972b5dd2f60SMing Lei } 1973b5dd2f60SMing Lei 1974d6296d39SChristoph Hellwig static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq, 1975d6296d39SChristoph Hellwig unsigned int hctx_idx, unsigned int numa_node) 1976b5dd2f60SMing Lei { 1977b5dd2f60SMing Lei struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); 1978b5dd2f60SMing Lei 19793989144fSPetr Mladek kthread_init_work(&cmd->work, loop_queue_work); 1980b5dd2f60SMing Lei return 0; 1981b5dd2f60SMing Lei } 1982b5dd2f60SMing Lei 1983f363b089SEric Biggers static const struct blk_mq_ops loop_mq_ops = { 1984b5dd2f60SMing Lei .queue_rq = loop_queue_rq, 1985b5dd2f60SMing Lei .init_request = loop_init_request, 1986fe2cb290SChristoph Hellwig .complete = lo_complete_rq, 1987b5dd2f60SMing Lei }; 1988b5dd2f60SMing Lei 198934dd82afSKay Sievers static int loop_add(struct loop_device **l, int i) 19901da177e4SLinus Torvalds { 199173285082SKen Chen struct loop_device *lo; 199273285082SKen Chen struct gendisk *disk; 199334dd82afSKay Sievers int err; 19941da177e4SLinus Torvalds 199534dd82afSKay Sievers err = -ENOMEM; 199668d740d7SSilva Paulo lo = kzalloc(sizeof(*lo), GFP_KERNEL); 199768d740d7SSilva Paulo if (!lo) 199873285082SKen Chen goto out; 199934dd82afSKay Sievers 2000ef7e7c82SMikulas Patocka lo->lo_state = Lo_unbound; 2001ef7e7c82SMikulas Patocka 2002c718aa65STejun Heo /* allocate id, if @id >= 0, we're requesting that specific id */ 200334dd82afSKay Sievers if (i >= 0) { 2004c718aa65STejun Heo err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL); 2005c718aa65STejun Heo if (err == -ENOSPC) 200634dd82afSKay Sievers err = -EEXIST; 200734dd82afSKay Sievers } else { 2008c718aa65STejun Heo err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL); 200934dd82afSKay Sievers } 201034dd82afSKay Sievers if (err < 0) 201134dd82afSKay Sievers goto out_free_dev; 2012c718aa65STejun Heo i = err; 20131da177e4SLinus Torvalds 2014183cfb57SWei Yongjun err = -ENOMEM; 2015b5dd2f60SMing Lei lo->tag_set.ops = &loop_mq_ops; 2016b5dd2f60SMing Lei lo->tag_set.nr_hw_queues = 1; 2017b5dd2f60SMing Lei lo->tag_set.queue_depth = 128; 2018b5dd2f60SMing Lei lo->tag_set.numa_node = NUMA_NO_NODE; 2019b5dd2f60SMing Lei lo->tag_set.cmd_size = sizeof(struct loop_cmd); 202056d18f62SMing Lei lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 2021b5dd2f60SMing Lei lo->tag_set.driver_data = lo; 2022b5dd2f60SMing Lei 2023b5dd2f60SMing Lei err = blk_mq_alloc_tag_set(&lo->tag_set); 2024b5dd2f60SMing Lei if (err) 20253ec981e3SMikulas Patocka goto out_free_idr; 202673285082SKen Chen 2027b5dd2f60SMing Lei lo->lo_queue = blk_mq_init_queue(&lo->tag_set); 202838a3499fSChengguang Xu if (IS_ERR(lo->lo_queue)) { 2029b5dd2f60SMing Lei err = PTR_ERR(lo->lo_queue); 2030b5dd2f60SMing Lei goto out_cleanup_tags; 2031b5dd2f60SMing Lei } 2032ef7e7c82SMikulas Patocka lo->lo_queue->queuedata = lo; 2033ef7e7c82SMikulas Patocka 203454bb0adeSShaohua Li blk_queue_max_hw_sectors(lo->lo_queue, BLK_DEF_MAX_SECTORS); 203540326d8aSShaohua Li 20365b5e20f4SMing Lei /* 203740326d8aSShaohua Li * By default, we do buffer IO, so it doesn't make sense to enable 203840326d8aSShaohua Li * merge because the I/O submitted to backing file is handled page by 203940326d8aSShaohua Li * page. For directio mode, merge does help to dispatch bigger request 204040326d8aSShaohua Li * to underlayer disk. We will enable merge once directio is enabled. 20415b5e20f4SMing Lei */ 20428b904b5bSBart Van Assche blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); 20435b5e20f4SMing Lei 20447a649737SMinfei Huang err = -ENOMEM; 2045476a4813SLaurent Vivier disk = lo->lo_disk = alloc_disk(1 << part_shift); 204673285082SKen Chen if (!disk) 204773285082SKen Chen goto out_free_queue; 204873285082SKen Chen 2049e03c8dd1SKay Sievers /* 2050e03c8dd1SKay Sievers * Disable partition scanning by default. The in-kernel partition 2051e03c8dd1SKay Sievers * scanning can be requested individually per-device during its 2052e03c8dd1SKay Sievers * setup. Userspace can always add and remove partitions from all 2053e03c8dd1SKay Sievers * devices. The needed partition minors are allocated from the 2054e03c8dd1SKay Sievers * extended minor space, the main loop device numbers will continue 2055e03c8dd1SKay Sievers * to match the loop minors, regardless of the number of partitions 2056e03c8dd1SKay Sievers * used. 2057e03c8dd1SKay Sievers * 2058e03c8dd1SKay Sievers * If max_part is given, partition scanning is globally enabled for 2059e03c8dd1SKay Sievers * all loop devices. The minors for the main loop devices will be 2060e03c8dd1SKay Sievers * multiples of max_part. 2061e03c8dd1SKay Sievers * 2062e03c8dd1SKay Sievers * Note: Global-for-all-devices, set-only-at-init, read-only module 2063e03c8dd1SKay Sievers * parameteters like 'max_loop' and 'max_part' make things needlessly 2064e03c8dd1SKay Sievers * complicated, are too static, inflexible and may surprise 2065e03c8dd1SKay Sievers * userspace tools. Parameters like this in general should be avoided. 2066e03c8dd1SKay Sievers */ 2067e03c8dd1SKay Sievers if (!part_shift) 2068e03c8dd1SKay Sievers disk->flags |= GENHD_FL_NO_PART_SCAN; 2069e03c8dd1SKay Sievers disk->flags |= GENHD_FL_EXT_DEVT; 2070f8933667SMing Lei atomic_set(&lo->lo_refcnt, 0); 20711da177e4SLinus Torvalds lo->lo_number = i; 20721da177e4SLinus Torvalds spin_lock_init(&lo->lo_lock); 20731da177e4SLinus Torvalds disk->major = LOOP_MAJOR; 2074476a4813SLaurent Vivier disk->first_minor = i << part_shift; 20751da177e4SLinus Torvalds disk->fops = &lo_fops; 20761da177e4SLinus Torvalds disk->private_data = lo; 20771da177e4SLinus Torvalds disk->queue = lo->lo_queue; 207873285082SKen Chen sprintf(disk->disk_name, "loop%d", i); 207934dd82afSKay Sievers add_disk(disk); 208034dd82afSKay Sievers *l = lo; 208134dd82afSKay Sievers return lo->lo_number; 208273285082SKen Chen 208373285082SKen Chen out_free_queue: 208473285082SKen Chen blk_cleanup_queue(lo->lo_queue); 2085b5dd2f60SMing Lei out_cleanup_tags: 2086b5dd2f60SMing Lei blk_mq_free_tag_set(&lo->tag_set); 20873ec981e3SMikulas Patocka out_free_idr: 20883ec981e3SMikulas Patocka idr_remove(&loop_index_idr, i); 208973285082SKen Chen out_free_dev: 209073285082SKen Chen kfree(lo); 209173285082SKen Chen out: 209234dd82afSKay Sievers return err; 20931da177e4SLinus Torvalds } 20941da177e4SLinus Torvalds 209534dd82afSKay Sievers static void loop_remove(struct loop_device *lo) 209673285082SKen Chen { 20976cd18e71SNeilBrown del_gendisk(lo->lo_disk); 20980fa8ebddSBart Van Assche blk_cleanup_queue(lo->lo_queue); 2099b5dd2f60SMing Lei blk_mq_free_tag_set(&lo->tag_set); 210073285082SKen Chen put_disk(lo->lo_disk); 210173285082SKen Chen kfree(lo); 210273285082SKen Chen } 210373285082SKen Chen 2104770fe30aSKay Sievers static int find_free_cb(int id, void *ptr, void *data) 2105770fe30aSKay Sievers { 2106770fe30aSKay Sievers struct loop_device *lo = ptr; 2107770fe30aSKay Sievers struct loop_device **l = data; 2108770fe30aSKay Sievers 2109770fe30aSKay Sievers if (lo->lo_state == Lo_unbound) { 2110770fe30aSKay Sievers *l = lo; 2111770fe30aSKay Sievers return 1; 2112770fe30aSKay Sievers } 2113770fe30aSKay Sievers return 0; 2114770fe30aSKay Sievers } 2115770fe30aSKay Sievers 211634dd82afSKay Sievers static int loop_lookup(struct loop_device **l, int i) 2117a47653fcSKen Chen { 2118a47653fcSKen Chen struct loop_device *lo; 211934dd82afSKay Sievers int ret = -ENODEV; 2120a47653fcSKen Chen 2121770fe30aSKay Sievers if (i < 0) { 2122770fe30aSKay Sievers int err; 2123770fe30aSKay Sievers 2124770fe30aSKay Sievers err = idr_for_each(&loop_index_idr, &find_free_cb, &lo); 2125770fe30aSKay Sievers if (err == 1) { 2126770fe30aSKay Sievers *l = lo; 2127770fe30aSKay Sievers ret = lo->lo_number; 2128770fe30aSKay Sievers } 2129770fe30aSKay Sievers goto out; 2130a47653fcSKen Chen } 2131a47653fcSKen Chen 2132770fe30aSKay Sievers /* lookup and return a specific i */ 213334dd82afSKay Sievers lo = idr_find(&loop_index_idr, i); 2134a47653fcSKen Chen if (lo) { 213534dd82afSKay Sievers *l = lo; 213634dd82afSKay Sievers ret = lo->lo_number; 2137a47653fcSKen Chen } 2138770fe30aSKay Sievers out: 213934dd82afSKay Sievers return ret; 2140a47653fcSKen Chen } 2141a47653fcSKen Chen 214273285082SKen Chen static struct kobject *loop_probe(dev_t dev, int *part, void *data) 214373285082SKen Chen { 2144705962ccSAl Viro struct loop_device *lo; 214507002e99SAl Viro struct kobject *kobj; 214634dd82afSKay Sievers int err; 214773285082SKen Chen 21480a42e99bSJan Kara mutex_lock(&loop_ctl_mutex); 214934dd82afSKay Sievers err = loop_lookup(&lo, MINOR(dev) >> part_shift); 215034dd82afSKay Sievers if (err < 0) 215134dd82afSKay Sievers err = loop_add(&lo, MINOR(dev) >> part_shift); 215234dd82afSKay Sievers if (err < 0) 2153a207f593SMikulas Patocka kobj = NULL; 215434dd82afSKay Sievers else 21553079c22eSJan Kara kobj = get_disk_and_module(lo->lo_disk); 21560a42e99bSJan Kara mutex_unlock(&loop_ctl_mutex); 215773285082SKen Chen 215873285082SKen Chen *part = 0; 215907002e99SAl Viro return kobj; 216073285082SKen Chen } 216173285082SKen Chen 2162770fe30aSKay Sievers static long loop_control_ioctl(struct file *file, unsigned int cmd, 2163770fe30aSKay Sievers unsigned long parm) 2164770fe30aSKay Sievers { 2165770fe30aSKay Sievers struct loop_device *lo; 21660a42e99bSJan Kara int ret; 2167770fe30aSKay Sievers 21680a42e99bSJan Kara ret = mutex_lock_killable(&loop_ctl_mutex); 21690a42e99bSJan Kara if (ret) 21700a42e99bSJan Kara return ret; 21710a42e99bSJan Kara 21720a42e99bSJan Kara ret = -ENOSYS; 2173770fe30aSKay Sievers switch (cmd) { 2174770fe30aSKay Sievers case LOOP_CTL_ADD: 2175770fe30aSKay Sievers ret = loop_lookup(&lo, parm); 2176770fe30aSKay Sievers if (ret >= 0) { 2177770fe30aSKay Sievers ret = -EEXIST; 2178770fe30aSKay Sievers break; 2179770fe30aSKay Sievers } 2180770fe30aSKay Sievers ret = loop_add(&lo, parm); 2181770fe30aSKay Sievers break; 2182770fe30aSKay Sievers case LOOP_CTL_REMOVE: 2183770fe30aSKay Sievers ret = loop_lookup(&lo, parm); 2184770fe30aSKay Sievers if (ret < 0) 2185770fe30aSKay Sievers break; 2186770fe30aSKay Sievers if (lo->lo_state != Lo_unbound) { 2187770fe30aSKay Sievers ret = -EBUSY; 2188770fe30aSKay Sievers break; 2189770fe30aSKay Sievers } 2190f8933667SMing Lei if (atomic_read(&lo->lo_refcnt) > 0) { 2191770fe30aSKay Sievers ret = -EBUSY; 2192770fe30aSKay Sievers break; 2193770fe30aSKay Sievers } 2194770fe30aSKay Sievers lo->lo_disk->private_data = NULL; 2195770fe30aSKay Sievers idr_remove(&loop_index_idr, lo->lo_number); 2196770fe30aSKay Sievers loop_remove(lo); 2197770fe30aSKay Sievers break; 2198770fe30aSKay Sievers case LOOP_CTL_GET_FREE: 2199770fe30aSKay Sievers ret = loop_lookup(&lo, -1); 2200770fe30aSKay Sievers if (ret >= 0) 2201770fe30aSKay Sievers break; 2202770fe30aSKay Sievers ret = loop_add(&lo, -1); 2203770fe30aSKay Sievers } 22040a42e99bSJan Kara mutex_unlock(&loop_ctl_mutex); 2205770fe30aSKay Sievers 2206770fe30aSKay Sievers return ret; 2207770fe30aSKay Sievers } 2208770fe30aSKay Sievers 2209770fe30aSKay Sievers static const struct file_operations loop_ctl_fops = { 2210770fe30aSKay Sievers .open = nonseekable_open, 2211770fe30aSKay Sievers .unlocked_ioctl = loop_control_ioctl, 2212770fe30aSKay Sievers .compat_ioctl = loop_control_ioctl, 2213770fe30aSKay Sievers .owner = THIS_MODULE, 2214770fe30aSKay Sievers .llseek = noop_llseek, 2215770fe30aSKay Sievers }; 2216770fe30aSKay Sievers 2217770fe30aSKay Sievers static struct miscdevice loop_misc = { 2218770fe30aSKay Sievers .minor = LOOP_CTRL_MINOR, 2219770fe30aSKay Sievers .name = "loop-control", 2220770fe30aSKay Sievers .fops = &loop_ctl_fops, 2221770fe30aSKay Sievers }; 2222770fe30aSKay Sievers 2223770fe30aSKay Sievers MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR); 2224770fe30aSKay Sievers MODULE_ALIAS("devname:loop-control"); 2225770fe30aSKay Sievers 222673285082SKen Chen static int __init loop_init(void) 222773285082SKen Chen { 2228a47653fcSKen Chen int i, nr; 2229a47653fcSKen Chen unsigned long range; 223034dd82afSKay Sievers struct loop_device *lo; 2231770fe30aSKay Sievers int err; 2232a47653fcSKen Chen 2233476a4813SLaurent Vivier part_shift = 0; 2234ac04fee0SNamhyung Kim if (max_part > 0) { 2235476a4813SLaurent Vivier part_shift = fls(max_part); 2236476a4813SLaurent Vivier 2237ac04fee0SNamhyung Kim /* 2238ac04fee0SNamhyung Kim * Adjust max_part according to part_shift as it is exported 2239ac04fee0SNamhyung Kim * to user space so that user can decide correct minor number 2240ac04fee0SNamhyung Kim * if [s]he want to create more devices. 2241ac04fee0SNamhyung Kim * 2242ac04fee0SNamhyung Kim * Note that -1 is required because partition 0 is reserved 2243ac04fee0SNamhyung Kim * for the whole disk. 2244ac04fee0SNamhyung Kim */ 2245ac04fee0SNamhyung Kim max_part = (1UL << part_shift) - 1; 2246ac04fee0SNamhyung Kim } 2247ac04fee0SNamhyung Kim 2248b1a66504SGuo Chao if ((1UL << part_shift) > DISK_MAX_PARTS) { 2249b1a66504SGuo Chao err = -EINVAL; 2250a8c1d064SAnton Volkov goto err_out; 2251b1a66504SGuo Chao } 225278f4bb36SNamhyung Kim 2253b1a66504SGuo Chao if (max_loop > 1UL << (MINORBITS - part_shift)) { 2254b1a66504SGuo Chao err = -EINVAL; 2255a8c1d064SAnton Volkov goto err_out; 2256b1a66504SGuo Chao } 225773285082SKen Chen 2258d134b00bSKay Sievers /* 2259d134b00bSKay Sievers * If max_loop is specified, create that many devices upfront. 2260d134b00bSKay Sievers * This also becomes a hard limit. If max_loop is not specified, 2261d134b00bSKay Sievers * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module 2262d134b00bSKay Sievers * init time. Loop devices can be requested on-demand with the 2263d134b00bSKay Sievers * /dev/loop-control interface, or be instantiated by accessing 2264d134b00bSKay Sievers * a 'dead' device node. 2265d134b00bSKay Sievers */ 226673285082SKen Chen if (max_loop) { 2267a47653fcSKen Chen nr = max_loop; 2268a1c15c59SNamhyung Kim range = max_loop << part_shift; 2269a47653fcSKen Chen } else { 2270d134b00bSKay Sievers nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; 2271a1c15c59SNamhyung Kim range = 1UL << MINORBITS; 227273285082SKen Chen } 2273a47653fcSKen Chen 2274a8c1d064SAnton Volkov err = misc_register(&loop_misc); 2275a8c1d064SAnton Volkov if (err < 0) 2276a8c1d064SAnton Volkov goto err_out; 2277a8c1d064SAnton Volkov 2278a8c1d064SAnton Volkov 2279b1a66504SGuo Chao if (register_blkdev(LOOP_MAJOR, "loop")) { 2280b1a66504SGuo Chao err = -EIO; 2281b1a66504SGuo Chao goto misc_out; 2282b1a66504SGuo Chao } 2283a47653fcSKen Chen 2284a47653fcSKen Chen blk_register_region(MKDEV(LOOP_MAJOR, 0), range, 2285a47653fcSKen Chen THIS_MODULE, loop_probe, NULL, NULL); 2286a47653fcSKen Chen 2287d134b00bSKay Sievers /* pre-create number of devices given by config or max_loop */ 22880a42e99bSJan Kara mutex_lock(&loop_ctl_mutex); 228934dd82afSKay Sievers for (i = 0; i < nr; i++) 229034dd82afSKay Sievers loop_add(&lo, i); 22910a42e99bSJan Kara mutex_unlock(&loop_ctl_mutex); 229234dd82afSKay Sievers 229373285082SKen Chen printk(KERN_INFO "loop: module loaded\n"); 22941da177e4SLinus Torvalds return 0; 2295b1a66504SGuo Chao 2296b1a66504SGuo Chao misc_out: 2297b1a66504SGuo Chao misc_deregister(&loop_misc); 2298a8c1d064SAnton Volkov err_out: 2299b1a66504SGuo Chao return err; 230034dd82afSKay Sievers } 2301a47653fcSKen Chen 230234dd82afSKay Sievers static int loop_exit_cb(int id, void *ptr, void *data) 230334dd82afSKay Sievers { 230434dd82afSKay Sievers struct loop_device *lo = ptr; 2305a47653fcSKen Chen 230634dd82afSKay Sievers loop_remove(lo); 230734dd82afSKay Sievers return 0; 23081da177e4SLinus Torvalds } 23091da177e4SLinus Torvalds 231073285082SKen Chen static void __exit loop_exit(void) 23111da177e4SLinus Torvalds { 2312a47653fcSKen Chen unsigned long range; 23131da177e4SLinus Torvalds 2314a1c15c59SNamhyung Kim range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; 2315a47653fcSKen Chen 231634dd82afSKay Sievers idr_for_each(&loop_index_idr, &loop_exit_cb, NULL); 231734dd82afSKay Sievers idr_destroy(&loop_index_idr); 231873285082SKen Chen 2319a47653fcSKen Chen blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); 232000d59405SAkinobu Mita unregister_blkdev(LOOP_MAJOR, "loop"); 2321770fe30aSKay Sievers 2322770fe30aSKay Sievers misc_deregister(&loop_misc); 23231da177e4SLinus Torvalds } 23241da177e4SLinus Torvalds 23251da177e4SLinus Torvalds module_init(loop_init); 23261da177e4SLinus Torvalds module_exit(loop_exit); 23271da177e4SLinus Torvalds 23281da177e4SLinus Torvalds #ifndef MODULE 23291da177e4SLinus Torvalds static int __init max_loop_setup(char *str) 23301da177e4SLinus Torvalds { 23311da177e4SLinus Torvalds max_loop = simple_strtol(str, NULL, 0); 23321da177e4SLinus Torvalds return 1; 23331da177e4SLinus Torvalds } 23341da177e4SLinus Torvalds 23351da177e4SLinus Torvalds __setup("max_loop=", max_loop_setup); 23361da177e4SLinus Torvalds #endif 2337