1*1da177e4SLinus Torvalds /* 2*1da177e4SLinus Torvalds * linux/drivers/block/loop.c 3*1da177e4SLinus Torvalds * 4*1da177e4SLinus Torvalds * Written by Theodore Ts'o, 3/29/93 5*1da177e4SLinus Torvalds * 6*1da177e4SLinus Torvalds * Copyright 1993 by Theodore Ts'o. Redistribution of this file is 7*1da177e4SLinus Torvalds * permitted under the GNU General Public License. 8*1da177e4SLinus Torvalds * 9*1da177e4SLinus Torvalds * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993 10*1da177e4SLinus Torvalds * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996 11*1da177e4SLinus Torvalds * 12*1da177e4SLinus Torvalds * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994 13*1da177e4SLinus Torvalds * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996 14*1da177e4SLinus Torvalds * 15*1da177e4SLinus Torvalds * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997 16*1da177e4SLinus Torvalds * 17*1da177e4SLinus Torvalds * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998 18*1da177e4SLinus Torvalds * 19*1da177e4SLinus Torvalds * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998 20*1da177e4SLinus Torvalds * 21*1da177e4SLinus Torvalds * Loadable modules and other fixes by AK, 1998 22*1da177e4SLinus Torvalds * 23*1da177e4SLinus Torvalds * Make real block number available to downstream transfer functions, enables 24*1da177e4SLinus Torvalds * CBC (and relatives) mode encryption requiring unique IVs per data block. 25*1da177e4SLinus Torvalds * Reed H. Petty, rhp@draper.net 26*1da177e4SLinus Torvalds * 27*1da177e4SLinus Torvalds * Maximum number of loop devices now dynamic via max_loop module parameter. 28*1da177e4SLinus Torvalds * Russell Kroll <rkroll@exploits.org> 19990701 29*1da177e4SLinus Torvalds * 30*1da177e4SLinus Torvalds * Maximum number of loop devices when compiled-in now selectable by passing 31*1da177e4SLinus Torvalds * max_loop=<1-255> to the kernel on boot. 32*1da177e4SLinus Torvalds * Erik I. Bols�, <eriki@himolde.no>, Oct 31, 1999 33*1da177e4SLinus Torvalds * 34*1da177e4SLinus Torvalds * Completely rewrite request handling to be make_request_fn style and 35*1da177e4SLinus Torvalds * non blocking, pushing work to a helper thread. Lots of fixes from 36*1da177e4SLinus Torvalds * Al Viro too. 37*1da177e4SLinus Torvalds * Jens Axboe <axboe@suse.de>, Nov 2000 38*1da177e4SLinus Torvalds * 39*1da177e4SLinus Torvalds * Support up to 256 loop devices 40*1da177e4SLinus Torvalds * Heinz Mauelshagen <mge@sistina.com>, Feb 2002 41*1da177e4SLinus Torvalds * 42*1da177e4SLinus Torvalds * Support for falling back on the write file operation when the address space 43*1da177e4SLinus Torvalds * operations prepare_write and/or commit_write are not available on the 44*1da177e4SLinus Torvalds * backing filesystem. 45*1da177e4SLinus Torvalds * Anton Altaparmakov, 16 Feb 2005 46*1da177e4SLinus Torvalds * 47*1da177e4SLinus Torvalds * Still To Fix: 48*1da177e4SLinus Torvalds * - Advisory locking is ignored here. 49*1da177e4SLinus Torvalds * - Should use an own CAP_* category instead of CAP_SYS_ADMIN 50*1da177e4SLinus Torvalds * 51*1da177e4SLinus Torvalds */ 52*1da177e4SLinus Torvalds 53*1da177e4SLinus Torvalds #include <linux/config.h> 54*1da177e4SLinus Torvalds #include <linux/module.h> 55*1da177e4SLinus Torvalds #include <linux/moduleparam.h> 56*1da177e4SLinus Torvalds #include <linux/sched.h> 57*1da177e4SLinus Torvalds #include <linux/fs.h> 58*1da177e4SLinus Torvalds #include <linux/file.h> 59*1da177e4SLinus Torvalds #include <linux/stat.h> 60*1da177e4SLinus Torvalds #include <linux/errno.h> 61*1da177e4SLinus Torvalds #include <linux/major.h> 62*1da177e4SLinus Torvalds #include <linux/wait.h> 63*1da177e4SLinus Torvalds #include <linux/blkdev.h> 64*1da177e4SLinus Torvalds #include <linux/blkpg.h> 65*1da177e4SLinus Torvalds #include <linux/init.h> 66*1da177e4SLinus Torvalds #include <linux/devfs_fs_kernel.h> 67*1da177e4SLinus Torvalds #include <linux/smp_lock.h> 68*1da177e4SLinus Torvalds #include <linux/swap.h> 69*1da177e4SLinus Torvalds #include <linux/slab.h> 70*1da177e4SLinus Torvalds #include <linux/loop.h> 71*1da177e4SLinus Torvalds #include <linux/suspend.h> 72*1da177e4SLinus Torvalds #include <linux/writeback.h> 73*1da177e4SLinus Torvalds #include <linux/buffer_head.h> /* for invalidate_bdev() */ 74*1da177e4SLinus Torvalds #include <linux/completion.h> 75*1da177e4SLinus Torvalds #include <linux/highmem.h> 76*1da177e4SLinus Torvalds #include <linux/gfp.h> 77*1da177e4SLinus Torvalds 78*1da177e4SLinus Torvalds #include <asm/uaccess.h> 79*1da177e4SLinus Torvalds 80*1da177e4SLinus Torvalds static int max_loop = 8; 81*1da177e4SLinus Torvalds static struct loop_device *loop_dev; 82*1da177e4SLinus Torvalds static struct gendisk **disks; 83*1da177e4SLinus Torvalds 84*1da177e4SLinus Torvalds /* 85*1da177e4SLinus Torvalds * Transfer functions 86*1da177e4SLinus Torvalds */ 87*1da177e4SLinus Torvalds static int transfer_none(struct loop_device *lo, int cmd, 88*1da177e4SLinus Torvalds struct page *raw_page, unsigned raw_off, 89*1da177e4SLinus Torvalds struct page *loop_page, unsigned loop_off, 90*1da177e4SLinus Torvalds int size, sector_t real_block) 91*1da177e4SLinus Torvalds { 92*1da177e4SLinus Torvalds char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; 93*1da177e4SLinus Torvalds char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; 94*1da177e4SLinus Torvalds 95*1da177e4SLinus Torvalds if (cmd == READ) 96*1da177e4SLinus Torvalds memcpy(loop_buf, raw_buf, size); 97*1da177e4SLinus Torvalds else 98*1da177e4SLinus Torvalds memcpy(raw_buf, loop_buf, size); 99*1da177e4SLinus Torvalds 100*1da177e4SLinus Torvalds kunmap_atomic(raw_buf, KM_USER0); 101*1da177e4SLinus Torvalds kunmap_atomic(loop_buf, KM_USER1); 102*1da177e4SLinus Torvalds cond_resched(); 103*1da177e4SLinus Torvalds return 0; 104*1da177e4SLinus Torvalds } 105*1da177e4SLinus Torvalds 106*1da177e4SLinus Torvalds static int transfer_xor(struct loop_device *lo, int cmd, 107*1da177e4SLinus Torvalds struct page *raw_page, unsigned raw_off, 108*1da177e4SLinus Torvalds struct page *loop_page, unsigned loop_off, 109*1da177e4SLinus Torvalds int size, sector_t real_block) 110*1da177e4SLinus Torvalds { 111*1da177e4SLinus Torvalds char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; 112*1da177e4SLinus Torvalds char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; 113*1da177e4SLinus Torvalds char *in, *out, *key; 114*1da177e4SLinus Torvalds int i, keysize; 115*1da177e4SLinus Torvalds 116*1da177e4SLinus Torvalds if (cmd == READ) { 117*1da177e4SLinus Torvalds in = raw_buf; 118*1da177e4SLinus Torvalds out = loop_buf; 119*1da177e4SLinus Torvalds } else { 120*1da177e4SLinus Torvalds in = loop_buf; 121*1da177e4SLinus Torvalds out = raw_buf; 122*1da177e4SLinus Torvalds } 123*1da177e4SLinus Torvalds 124*1da177e4SLinus Torvalds key = lo->lo_encrypt_key; 125*1da177e4SLinus Torvalds keysize = lo->lo_encrypt_key_size; 126*1da177e4SLinus Torvalds for (i = 0; i < size; i++) 127*1da177e4SLinus Torvalds *out++ = *in++ ^ key[(i & 511) % keysize]; 128*1da177e4SLinus Torvalds 129*1da177e4SLinus Torvalds kunmap_atomic(raw_buf, KM_USER0); 130*1da177e4SLinus Torvalds kunmap_atomic(loop_buf, KM_USER1); 131*1da177e4SLinus Torvalds cond_resched(); 132*1da177e4SLinus Torvalds return 0; 133*1da177e4SLinus Torvalds } 134*1da177e4SLinus Torvalds 135*1da177e4SLinus Torvalds static int xor_init(struct loop_device *lo, const struct loop_info64 *info) 136*1da177e4SLinus Torvalds { 137*1da177e4SLinus Torvalds if (unlikely(info->lo_encrypt_key_size <= 0)) 138*1da177e4SLinus Torvalds return -EINVAL; 139*1da177e4SLinus Torvalds return 0; 140*1da177e4SLinus Torvalds } 141*1da177e4SLinus Torvalds 142*1da177e4SLinus Torvalds static struct loop_func_table none_funcs = { 143*1da177e4SLinus Torvalds .number = LO_CRYPT_NONE, 144*1da177e4SLinus Torvalds .transfer = transfer_none, 145*1da177e4SLinus Torvalds }; 146*1da177e4SLinus Torvalds 147*1da177e4SLinus Torvalds static struct loop_func_table xor_funcs = { 148*1da177e4SLinus Torvalds .number = LO_CRYPT_XOR, 149*1da177e4SLinus Torvalds .transfer = transfer_xor, 150*1da177e4SLinus Torvalds .init = xor_init 151*1da177e4SLinus Torvalds }; 152*1da177e4SLinus Torvalds 153*1da177e4SLinus Torvalds /* xfer_funcs[0] is special - its release function is never called */ 154*1da177e4SLinus Torvalds static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { 155*1da177e4SLinus Torvalds &none_funcs, 156*1da177e4SLinus Torvalds &xor_funcs 157*1da177e4SLinus Torvalds }; 158*1da177e4SLinus Torvalds 159*1da177e4SLinus Torvalds static loff_t get_loop_size(struct loop_device *lo, struct file *file) 160*1da177e4SLinus Torvalds { 161*1da177e4SLinus Torvalds loff_t size, offset, loopsize; 162*1da177e4SLinus Torvalds 163*1da177e4SLinus Torvalds /* Compute loopsize in bytes */ 164*1da177e4SLinus Torvalds size = i_size_read(file->f_mapping->host); 165*1da177e4SLinus Torvalds offset = lo->lo_offset; 166*1da177e4SLinus Torvalds loopsize = size - offset; 167*1da177e4SLinus Torvalds if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize) 168*1da177e4SLinus Torvalds loopsize = lo->lo_sizelimit; 169*1da177e4SLinus Torvalds 170*1da177e4SLinus Torvalds /* 171*1da177e4SLinus Torvalds * Unfortunately, if we want to do I/O on the device, 172*1da177e4SLinus Torvalds * the number of 512-byte sectors has to fit into a sector_t. 173*1da177e4SLinus Torvalds */ 174*1da177e4SLinus Torvalds return loopsize >> 9; 175*1da177e4SLinus Torvalds } 176*1da177e4SLinus Torvalds 177*1da177e4SLinus Torvalds static int 178*1da177e4SLinus Torvalds figure_loop_size(struct loop_device *lo) 179*1da177e4SLinus Torvalds { 180*1da177e4SLinus Torvalds loff_t size = get_loop_size(lo, lo->lo_backing_file); 181*1da177e4SLinus Torvalds sector_t x = (sector_t)size; 182*1da177e4SLinus Torvalds 183*1da177e4SLinus Torvalds if (unlikely((loff_t)x != size)) 184*1da177e4SLinus Torvalds return -EFBIG; 185*1da177e4SLinus Torvalds 186*1da177e4SLinus Torvalds set_capacity(disks[lo->lo_number], x); 187*1da177e4SLinus Torvalds return 0; 188*1da177e4SLinus Torvalds } 189*1da177e4SLinus Torvalds 190*1da177e4SLinus Torvalds static inline int 191*1da177e4SLinus Torvalds lo_do_transfer(struct loop_device *lo, int cmd, 192*1da177e4SLinus Torvalds struct page *rpage, unsigned roffs, 193*1da177e4SLinus Torvalds struct page *lpage, unsigned loffs, 194*1da177e4SLinus Torvalds int size, sector_t rblock) 195*1da177e4SLinus Torvalds { 196*1da177e4SLinus Torvalds if (unlikely(!lo->transfer)) 197*1da177e4SLinus Torvalds return 0; 198*1da177e4SLinus Torvalds 199*1da177e4SLinus Torvalds return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); 200*1da177e4SLinus Torvalds } 201*1da177e4SLinus Torvalds 202*1da177e4SLinus Torvalds /** 203*1da177e4SLinus Torvalds * do_lo_send_aops - helper for writing data to a loop device 204*1da177e4SLinus Torvalds * 205*1da177e4SLinus Torvalds * This is the fast version for backing filesystems which implement the address 206*1da177e4SLinus Torvalds * space operations prepare_write and commit_write. 207*1da177e4SLinus Torvalds */ 208*1da177e4SLinus Torvalds static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, 209*1da177e4SLinus Torvalds int bsize, loff_t pos, struct page *page) 210*1da177e4SLinus Torvalds { 211*1da177e4SLinus Torvalds struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */ 212*1da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 213*1da177e4SLinus Torvalds struct address_space_operations *aops = mapping->a_ops; 214*1da177e4SLinus Torvalds pgoff_t index; 215*1da177e4SLinus Torvalds unsigned offset, bv_offs; 216*1da177e4SLinus Torvalds int len, ret = 0; 217*1da177e4SLinus Torvalds 218*1da177e4SLinus Torvalds down(&mapping->host->i_sem); 219*1da177e4SLinus Torvalds index = pos >> PAGE_CACHE_SHIFT; 220*1da177e4SLinus Torvalds offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1); 221*1da177e4SLinus Torvalds bv_offs = bvec->bv_offset; 222*1da177e4SLinus Torvalds len = bvec->bv_len; 223*1da177e4SLinus Torvalds while (len > 0) { 224*1da177e4SLinus Torvalds sector_t IV; 225*1da177e4SLinus Torvalds unsigned size; 226*1da177e4SLinus Torvalds int transfer_result; 227*1da177e4SLinus Torvalds 228*1da177e4SLinus Torvalds IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); 229*1da177e4SLinus Torvalds size = PAGE_CACHE_SIZE - offset; 230*1da177e4SLinus Torvalds if (size > len) 231*1da177e4SLinus Torvalds size = len; 232*1da177e4SLinus Torvalds page = grab_cache_page(mapping, index); 233*1da177e4SLinus Torvalds if (unlikely(!page)) 234*1da177e4SLinus Torvalds goto fail; 235*1da177e4SLinus Torvalds if (unlikely(aops->prepare_write(file, page, offset, 236*1da177e4SLinus Torvalds offset + size))) 237*1da177e4SLinus Torvalds goto unlock; 238*1da177e4SLinus Torvalds transfer_result = lo_do_transfer(lo, WRITE, page, offset, 239*1da177e4SLinus Torvalds bvec->bv_page, bv_offs, size, IV); 240*1da177e4SLinus Torvalds if (unlikely(transfer_result)) { 241*1da177e4SLinus Torvalds char *kaddr; 242*1da177e4SLinus Torvalds 243*1da177e4SLinus Torvalds /* 244*1da177e4SLinus Torvalds * The transfer failed, but we still write the data to 245*1da177e4SLinus Torvalds * keep prepare/commit calls balanced. 246*1da177e4SLinus Torvalds */ 247*1da177e4SLinus Torvalds printk(KERN_ERR "loop: transfer error block %llu\n", 248*1da177e4SLinus Torvalds (unsigned long long)index); 249*1da177e4SLinus Torvalds kaddr = kmap_atomic(page, KM_USER0); 250*1da177e4SLinus Torvalds memset(kaddr + offset, 0, size); 251*1da177e4SLinus Torvalds kunmap_atomic(kaddr, KM_USER0); 252*1da177e4SLinus Torvalds } 253*1da177e4SLinus Torvalds flush_dcache_page(page); 254*1da177e4SLinus Torvalds if (unlikely(aops->commit_write(file, page, offset, 255*1da177e4SLinus Torvalds offset + size))) 256*1da177e4SLinus Torvalds goto unlock; 257*1da177e4SLinus Torvalds if (unlikely(transfer_result)) 258*1da177e4SLinus Torvalds goto unlock; 259*1da177e4SLinus Torvalds bv_offs += size; 260*1da177e4SLinus Torvalds len -= size; 261*1da177e4SLinus Torvalds offset = 0; 262*1da177e4SLinus Torvalds index++; 263*1da177e4SLinus Torvalds pos += size; 264*1da177e4SLinus Torvalds unlock_page(page); 265*1da177e4SLinus Torvalds page_cache_release(page); 266*1da177e4SLinus Torvalds } 267*1da177e4SLinus Torvalds out: 268*1da177e4SLinus Torvalds up(&mapping->host->i_sem); 269*1da177e4SLinus Torvalds return ret; 270*1da177e4SLinus Torvalds unlock: 271*1da177e4SLinus Torvalds unlock_page(page); 272*1da177e4SLinus Torvalds page_cache_release(page); 273*1da177e4SLinus Torvalds fail: 274*1da177e4SLinus Torvalds ret = -1; 275*1da177e4SLinus Torvalds goto out; 276*1da177e4SLinus Torvalds } 277*1da177e4SLinus Torvalds 278*1da177e4SLinus Torvalds /** 279*1da177e4SLinus Torvalds * __do_lo_send_write - helper for writing data to a loop device 280*1da177e4SLinus Torvalds * 281*1da177e4SLinus Torvalds * This helper just factors out common code between do_lo_send_direct_write() 282*1da177e4SLinus Torvalds * and do_lo_send_write(). 283*1da177e4SLinus Torvalds */ 284*1da177e4SLinus Torvalds static inline int __do_lo_send_write(struct file *file, 285*1da177e4SLinus Torvalds u8 __user *buf, const int len, loff_t pos) 286*1da177e4SLinus Torvalds { 287*1da177e4SLinus Torvalds ssize_t bw; 288*1da177e4SLinus Torvalds mm_segment_t old_fs = get_fs(); 289*1da177e4SLinus Torvalds 290*1da177e4SLinus Torvalds set_fs(get_ds()); 291*1da177e4SLinus Torvalds bw = file->f_op->write(file, buf, len, &pos); 292*1da177e4SLinus Torvalds set_fs(old_fs); 293*1da177e4SLinus Torvalds if (likely(bw == len)) 294*1da177e4SLinus Torvalds return 0; 295*1da177e4SLinus Torvalds printk(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", 296*1da177e4SLinus Torvalds (unsigned long long)pos, len); 297*1da177e4SLinus Torvalds if (bw >= 0) 298*1da177e4SLinus Torvalds bw = -EIO; 299*1da177e4SLinus Torvalds return bw; 300*1da177e4SLinus Torvalds } 301*1da177e4SLinus Torvalds 302*1da177e4SLinus Torvalds /** 303*1da177e4SLinus Torvalds * do_lo_send_direct_write - helper for writing data to a loop device 304*1da177e4SLinus Torvalds * 305*1da177e4SLinus Torvalds * This is the fast, non-transforming version for backing filesystems which do 306*1da177e4SLinus Torvalds * not implement the address space operations prepare_write and commit_write. 307*1da177e4SLinus Torvalds * It uses the write file operation which should be present on all writeable 308*1da177e4SLinus Torvalds * filesystems. 309*1da177e4SLinus Torvalds */ 310*1da177e4SLinus Torvalds static int do_lo_send_direct_write(struct loop_device *lo, 311*1da177e4SLinus Torvalds struct bio_vec *bvec, int bsize, loff_t pos, struct page *page) 312*1da177e4SLinus Torvalds { 313*1da177e4SLinus Torvalds ssize_t bw = __do_lo_send_write(lo->lo_backing_file, 314*1da177e4SLinus Torvalds (u8 __user *)kmap(bvec->bv_page) + bvec->bv_offset, 315*1da177e4SLinus Torvalds bvec->bv_len, pos); 316*1da177e4SLinus Torvalds kunmap(bvec->bv_page); 317*1da177e4SLinus Torvalds cond_resched(); 318*1da177e4SLinus Torvalds return bw; 319*1da177e4SLinus Torvalds } 320*1da177e4SLinus Torvalds 321*1da177e4SLinus Torvalds /** 322*1da177e4SLinus Torvalds * do_lo_send_write - helper for writing data to a loop device 323*1da177e4SLinus Torvalds * 324*1da177e4SLinus Torvalds * This is the slow, transforming version for filesystems which do not 325*1da177e4SLinus Torvalds * implement the address space operations prepare_write and commit_write. It 326*1da177e4SLinus Torvalds * uses the write file operation which should be present on all writeable 327*1da177e4SLinus Torvalds * filesystems. 328*1da177e4SLinus Torvalds * 329*1da177e4SLinus Torvalds * Using fops->write is slower than using aops->{prepare,commit}_write in the 330*1da177e4SLinus Torvalds * transforming case because we need to double buffer the data as we cannot do 331*1da177e4SLinus Torvalds * the transformations in place as we do not have direct access to the 332*1da177e4SLinus Torvalds * destination pages of the backing file. 333*1da177e4SLinus Torvalds */ 334*1da177e4SLinus Torvalds static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, 335*1da177e4SLinus Torvalds int bsize, loff_t pos, struct page *page) 336*1da177e4SLinus Torvalds { 337*1da177e4SLinus Torvalds int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, 338*1da177e4SLinus Torvalds bvec->bv_offset, bvec->bv_len, pos >> 9); 339*1da177e4SLinus Torvalds if (likely(!ret)) 340*1da177e4SLinus Torvalds return __do_lo_send_write(lo->lo_backing_file, 341*1da177e4SLinus Torvalds (u8 __user *)page_address(page), bvec->bv_len, 342*1da177e4SLinus Torvalds pos); 343*1da177e4SLinus Torvalds printk(KERN_ERR "loop: Transfer error at byte offset %llu, " 344*1da177e4SLinus Torvalds "length %i.\n", (unsigned long long)pos, bvec->bv_len); 345*1da177e4SLinus Torvalds if (ret > 0) 346*1da177e4SLinus Torvalds ret = -EIO; 347*1da177e4SLinus Torvalds return ret; 348*1da177e4SLinus Torvalds } 349*1da177e4SLinus Torvalds 350*1da177e4SLinus Torvalds static int lo_send(struct loop_device *lo, struct bio *bio, int bsize, 351*1da177e4SLinus Torvalds loff_t pos) 352*1da177e4SLinus Torvalds { 353*1da177e4SLinus Torvalds int (*do_lo_send)(struct loop_device *, struct bio_vec *, int, loff_t, 354*1da177e4SLinus Torvalds struct page *page); 355*1da177e4SLinus Torvalds struct bio_vec *bvec; 356*1da177e4SLinus Torvalds struct page *page = NULL; 357*1da177e4SLinus Torvalds int i, ret = 0; 358*1da177e4SLinus Torvalds 359*1da177e4SLinus Torvalds do_lo_send = do_lo_send_aops; 360*1da177e4SLinus Torvalds if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) { 361*1da177e4SLinus Torvalds do_lo_send = do_lo_send_direct_write; 362*1da177e4SLinus Torvalds if (lo->transfer != transfer_none) { 363*1da177e4SLinus Torvalds page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); 364*1da177e4SLinus Torvalds if (unlikely(!page)) 365*1da177e4SLinus Torvalds goto fail; 366*1da177e4SLinus Torvalds kmap(page); 367*1da177e4SLinus Torvalds do_lo_send = do_lo_send_write; 368*1da177e4SLinus Torvalds } 369*1da177e4SLinus Torvalds } 370*1da177e4SLinus Torvalds bio_for_each_segment(bvec, bio, i) { 371*1da177e4SLinus Torvalds ret = do_lo_send(lo, bvec, bsize, pos, page); 372*1da177e4SLinus Torvalds if (ret < 0) 373*1da177e4SLinus Torvalds break; 374*1da177e4SLinus Torvalds pos += bvec->bv_len; 375*1da177e4SLinus Torvalds } 376*1da177e4SLinus Torvalds if (page) { 377*1da177e4SLinus Torvalds kunmap(page); 378*1da177e4SLinus Torvalds __free_page(page); 379*1da177e4SLinus Torvalds } 380*1da177e4SLinus Torvalds out: 381*1da177e4SLinus Torvalds return ret; 382*1da177e4SLinus Torvalds fail: 383*1da177e4SLinus Torvalds printk(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); 384*1da177e4SLinus Torvalds ret = -ENOMEM; 385*1da177e4SLinus Torvalds goto out; 386*1da177e4SLinus Torvalds } 387*1da177e4SLinus Torvalds 388*1da177e4SLinus Torvalds struct lo_read_data { 389*1da177e4SLinus Torvalds struct loop_device *lo; 390*1da177e4SLinus Torvalds struct page *page; 391*1da177e4SLinus Torvalds unsigned offset; 392*1da177e4SLinus Torvalds int bsize; 393*1da177e4SLinus Torvalds }; 394*1da177e4SLinus Torvalds 395*1da177e4SLinus Torvalds static int 396*1da177e4SLinus Torvalds lo_read_actor(read_descriptor_t *desc, struct page *page, 397*1da177e4SLinus Torvalds unsigned long offset, unsigned long size) 398*1da177e4SLinus Torvalds { 399*1da177e4SLinus Torvalds unsigned long count = desc->count; 400*1da177e4SLinus Torvalds struct lo_read_data *p = desc->arg.data; 401*1da177e4SLinus Torvalds struct loop_device *lo = p->lo; 402*1da177e4SLinus Torvalds sector_t IV; 403*1da177e4SLinus Torvalds 404*1da177e4SLinus Torvalds IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); 405*1da177e4SLinus Torvalds 406*1da177e4SLinus Torvalds if (size > count) 407*1da177e4SLinus Torvalds size = count; 408*1da177e4SLinus Torvalds 409*1da177e4SLinus Torvalds if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) { 410*1da177e4SLinus Torvalds size = 0; 411*1da177e4SLinus Torvalds printk(KERN_ERR "loop: transfer error block %ld\n", 412*1da177e4SLinus Torvalds page->index); 413*1da177e4SLinus Torvalds desc->error = -EINVAL; 414*1da177e4SLinus Torvalds } 415*1da177e4SLinus Torvalds 416*1da177e4SLinus Torvalds flush_dcache_page(p->page); 417*1da177e4SLinus Torvalds 418*1da177e4SLinus Torvalds desc->count = count - size; 419*1da177e4SLinus Torvalds desc->written += size; 420*1da177e4SLinus Torvalds p->offset += size; 421*1da177e4SLinus Torvalds return size; 422*1da177e4SLinus Torvalds } 423*1da177e4SLinus Torvalds 424*1da177e4SLinus Torvalds static int 425*1da177e4SLinus Torvalds do_lo_receive(struct loop_device *lo, 426*1da177e4SLinus Torvalds struct bio_vec *bvec, int bsize, loff_t pos) 427*1da177e4SLinus Torvalds { 428*1da177e4SLinus Torvalds struct lo_read_data cookie; 429*1da177e4SLinus Torvalds struct file *file; 430*1da177e4SLinus Torvalds int retval; 431*1da177e4SLinus Torvalds 432*1da177e4SLinus Torvalds cookie.lo = lo; 433*1da177e4SLinus Torvalds cookie.page = bvec->bv_page; 434*1da177e4SLinus Torvalds cookie.offset = bvec->bv_offset; 435*1da177e4SLinus Torvalds cookie.bsize = bsize; 436*1da177e4SLinus Torvalds file = lo->lo_backing_file; 437*1da177e4SLinus Torvalds retval = file->f_op->sendfile(file, &pos, bvec->bv_len, 438*1da177e4SLinus Torvalds lo_read_actor, &cookie); 439*1da177e4SLinus Torvalds return (retval < 0)? retval: 0; 440*1da177e4SLinus Torvalds } 441*1da177e4SLinus Torvalds 442*1da177e4SLinus Torvalds static int 443*1da177e4SLinus Torvalds lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos) 444*1da177e4SLinus Torvalds { 445*1da177e4SLinus Torvalds struct bio_vec *bvec; 446*1da177e4SLinus Torvalds int i, ret = 0; 447*1da177e4SLinus Torvalds 448*1da177e4SLinus Torvalds bio_for_each_segment(bvec, bio, i) { 449*1da177e4SLinus Torvalds ret = do_lo_receive(lo, bvec, bsize, pos); 450*1da177e4SLinus Torvalds if (ret < 0) 451*1da177e4SLinus Torvalds break; 452*1da177e4SLinus Torvalds pos += bvec->bv_len; 453*1da177e4SLinus Torvalds } 454*1da177e4SLinus Torvalds return ret; 455*1da177e4SLinus Torvalds } 456*1da177e4SLinus Torvalds 457*1da177e4SLinus Torvalds static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) 458*1da177e4SLinus Torvalds { 459*1da177e4SLinus Torvalds loff_t pos; 460*1da177e4SLinus Torvalds int ret; 461*1da177e4SLinus Torvalds 462*1da177e4SLinus Torvalds pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; 463*1da177e4SLinus Torvalds if (bio_rw(bio) == WRITE) 464*1da177e4SLinus Torvalds ret = lo_send(lo, bio, lo->lo_blocksize, pos); 465*1da177e4SLinus Torvalds else 466*1da177e4SLinus Torvalds ret = lo_receive(lo, bio, lo->lo_blocksize, pos); 467*1da177e4SLinus Torvalds return ret; 468*1da177e4SLinus Torvalds } 469*1da177e4SLinus Torvalds 470*1da177e4SLinus Torvalds /* 471*1da177e4SLinus Torvalds * Add bio to back of pending list 472*1da177e4SLinus Torvalds */ 473*1da177e4SLinus Torvalds static void loop_add_bio(struct loop_device *lo, struct bio *bio) 474*1da177e4SLinus Torvalds { 475*1da177e4SLinus Torvalds unsigned long flags; 476*1da177e4SLinus Torvalds 477*1da177e4SLinus Torvalds spin_lock_irqsave(&lo->lo_lock, flags); 478*1da177e4SLinus Torvalds if (lo->lo_biotail) { 479*1da177e4SLinus Torvalds lo->lo_biotail->bi_next = bio; 480*1da177e4SLinus Torvalds lo->lo_biotail = bio; 481*1da177e4SLinus Torvalds } else 482*1da177e4SLinus Torvalds lo->lo_bio = lo->lo_biotail = bio; 483*1da177e4SLinus Torvalds spin_unlock_irqrestore(&lo->lo_lock, flags); 484*1da177e4SLinus Torvalds 485*1da177e4SLinus Torvalds up(&lo->lo_bh_mutex); 486*1da177e4SLinus Torvalds } 487*1da177e4SLinus Torvalds 488*1da177e4SLinus Torvalds /* 489*1da177e4SLinus Torvalds * Grab first pending buffer 490*1da177e4SLinus Torvalds */ 491*1da177e4SLinus Torvalds static struct bio *loop_get_bio(struct loop_device *lo) 492*1da177e4SLinus Torvalds { 493*1da177e4SLinus Torvalds struct bio *bio; 494*1da177e4SLinus Torvalds 495*1da177e4SLinus Torvalds spin_lock_irq(&lo->lo_lock); 496*1da177e4SLinus Torvalds if ((bio = lo->lo_bio)) { 497*1da177e4SLinus Torvalds if (bio == lo->lo_biotail) 498*1da177e4SLinus Torvalds lo->lo_biotail = NULL; 499*1da177e4SLinus Torvalds lo->lo_bio = bio->bi_next; 500*1da177e4SLinus Torvalds bio->bi_next = NULL; 501*1da177e4SLinus Torvalds } 502*1da177e4SLinus Torvalds spin_unlock_irq(&lo->lo_lock); 503*1da177e4SLinus Torvalds 504*1da177e4SLinus Torvalds return bio; 505*1da177e4SLinus Torvalds } 506*1da177e4SLinus Torvalds 507*1da177e4SLinus Torvalds static int loop_make_request(request_queue_t *q, struct bio *old_bio) 508*1da177e4SLinus Torvalds { 509*1da177e4SLinus Torvalds struct loop_device *lo = q->queuedata; 510*1da177e4SLinus Torvalds int rw = bio_rw(old_bio); 511*1da177e4SLinus Torvalds 512*1da177e4SLinus Torvalds if (!lo) 513*1da177e4SLinus Torvalds goto out; 514*1da177e4SLinus Torvalds 515*1da177e4SLinus Torvalds spin_lock_irq(&lo->lo_lock); 516*1da177e4SLinus Torvalds if (lo->lo_state != Lo_bound) 517*1da177e4SLinus Torvalds goto inactive; 518*1da177e4SLinus Torvalds atomic_inc(&lo->lo_pending); 519*1da177e4SLinus Torvalds spin_unlock_irq(&lo->lo_lock); 520*1da177e4SLinus Torvalds 521*1da177e4SLinus Torvalds if (rw == WRITE) { 522*1da177e4SLinus Torvalds if (lo->lo_flags & LO_FLAGS_READ_ONLY) 523*1da177e4SLinus Torvalds goto err; 524*1da177e4SLinus Torvalds } else if (rw == READA) { 525*1da177e4SLinus Torvalds rw = READ; 526*1da177e4SLinus Torvalds } else if (rw != READ) { 527*1da177e4SLinus Torvalds printk(KERN_ERR "loop: unknown command (%x)\n", rw); 528*1da177e4SLinus Torvalds goto err; 529*1da177e4SLinus Torvalds } 530*1da177e4SLinus Torvalds loop_add_bio(lo, old_bio); 531*1da177e4SLinus Torvalds return 0; 532*1da177e4SLinus Torvalds err: 533*1da177e4SLinus Torvalds if (atomic_dec_and_test(&lo->lo_pending)) 534*1da177e4SLinus Torvalds up(&lo->lo_bh_mutex); 535*1da177e4SLinus Torvalds out: 536*1da177e4SLinus Torvalds bio_io_error(old_bio, old_bio->bi_size); 537*1da177e4SLinus Torvalds return 0; 538*1da177e4SLinus Torvalds inactive: 539*1da177e4SLinus Torvalds spin_unlock_irq(&lo->lo_lock); 540*1da177e4SLinus Torvalds goto out; 541*1da177e4SLinus Torvalds } 542*1da177e4SLinus Torvalds 543*1da177e4SLinus Torvalds /* 544*1da177e4SLinus Torvalds * kick off io on the underlying address space 545*1da177e4SLinus Torvalds */ 546*1da177e4SLinus Torvalds static void loop_unplug(request_queue_t *q) 547*1da177e4SLinus Torvalds { 548*1da177e4SLinus Torvalds struct loop_device *lo = q->queuedata; 549*1da177e4SLinus Torvalds 550*1da177e4SLinus Torvalds clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags); 551*1da177e4SLinus Torvalds blk_run_address_space(lo->lo_backing_file->f_mapping); 552*1da177e4SLinus Torvalds } 553*1da177e4SLinus Torvalds 554*1da177e4SLinus Torvalds struct switch_request { 555*1da177e4SLinus Torvalds struct file *file; 556*1da177e4SLinus Torvalds struct completion wait; 557*1da177e4SLinus Torvalds }; 558*1da177e4SLinus Torvalds 559*1da177e4SLinus Torvalds static void do_loop_switch(struct loop_device *, struct switch_request *); 560*1da177e4SLinus Torvalds 561*1da177e4SLinus Torvalds static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) 562*1da177e4SLinus Torvalds { 563*1da177e4SLinus Torvalds int ret; 564*1da177e4SLinus Torvalds 565*1da177e4SLinus Torvalds if (unlikely(!bio->bi_bdev)) { 566*1da177e4SLinus Torvalds do_loop_switch(lo, bio->bi_private); 567*1da177e4SLinus Torvalds bio_put(bio); 568*1da177e4SLinus Torvalds } else { 569*1da177e4SLinus Torvalds ret = do_bio_filebacked(lo, bio); 570*1da177e4SLinus Torvalds bio_endio(bio, bio->bi_size, ret); 571*1da177e4SLinus Torvalds } 572*1da177e4SLinus Torvalds } 573*1da177e4SLinus Torvalds 574*1da177e4SLinus Torvalds /* 575*1da177e4SLinus Torvalds * worker thread that handles reads/writes to file backed loop devices, 576*1da177e4SLinus Torvalds * to avoid blocking in our make_request_fn. it also does loop decrypting 577*1da177e4SLinus Torvalds * on reads for block backed loop, as that is too heavy to do from 578*1da177e4SLinus Torvalds * b_end_io context where irqs may be disabled. 579*1da177e4SLinus Torvalds */ 580*1da177e4SLinus Torvalds static int loop_thread(void *data) 581*1da177e4SLinus Torvalds { 582*1da177e4SLinus Torvalds struct loop_device *lo = data; 583*1da177e4SLinus Torvalds struct bio *bio; 584*1da177e4SLinus Torvalds 585*1da177e4SLinus Torvalds daemonize("loop%d", lo->lo_number); 586*1da177e4SLinus Torvalds 587*1da177e4SLinus Torvalds /* 588*1da177e4SLinus Torvalds * loop can be used in an encrypted device, 589*1da177e4SLinus Torvalds * hence, it mustn't be stopped at all 590*1da177e4SLinus Torvalds * because it could be indirectly used during suspension 591*1da177e4SLinus Torvalds */ 592*1da177e4SLinus Torvalds current->flags |= PF_NOFREEZE; 593*1da177e4SLinus Torvalds 594*1da177e4SLinus Torvalds set_user_nice(current, -20); 595*1da177e4SLinus Torvalds 596*1da177e4SLinus Torvalds lo->lo_state = Lo_bound; 597*1da177e4SLinus Torvalds atomic_inc(&lo->lo_pending); 598*1da177e4SLinus Torvalds 599*1da177e4SLinus Torvalds /* 600*1da177e4SLinus Torvalds * up sem, we are running 601*1da177e4SLinus Torvalds */ 602*1da177e4SLinus Torvalds up(&lo->lo_sem); 603*1da177e4SLinus Torvalds 604*1da177e4SLinus Torvalds for (;;) { 605*1da177e4SLinus Torvalds down_interruptible(&lo->lo_bh_mutex); 606*1da177e4SLinus Torvalds /* 607*1da177e4SLinus Torvalds * could be upped because of tear-down, not because of 608*1da177e4SLinus Torvalds * pending work 609*1da177e4SLinus Torvalds */ 610*1da177e4SLinus Torvalds if (!atomic_read(&lo->lo_pending)) 611*1da177e4SLinus Torvalds break; 612*1da177e4SLinus Torvalds 613*1da177e4SLinus Torvalds bio = loop_get_bio(lo); 614*1da177e4SLinus Torvalds if (!bio) { 615*1da177e4SLinus Torvalds printk("loop: missing bio\n"); 616*1da177e4SLinus Torvalds continue; 617*1da177e4SLinus Torvalds } 618*1da177e4SLinus Torvalds loop_handle_bio(lo, bio); 619*1da177e4SLinus Torvalds 620*1da177e4SLinus Torvalds /* 621*1da177e4SLinus Torvalds * upped both for pending work and tear-down, lo_pending 622*1da177e4SLinus Torvalds * will hit zero then 623*1da177e4SLinus Torvalds */ 624*1da177e4SLinus Torvalds if (atomic_dec_and_test(&lo->lo_pending)) 625*1da177e4SLinus Torvalds break; 626*1da177e4SLinus Torvalds } 627*1da177e4SLinus Torvalds 628*1da177e4SLinus Torvalds up(&lo->lo_sem); 629*1da177e4SLinus Torvalds return 0; 630*1da177e4SLinus Torvalds } 631*1da177e4SLinus Torvalds 632*1da177e4SLinus Torvalds /* 633*1da177e4SLinus Torvalds * loop_switch performs the hard work of switching a backing store. 634*1da177e4SLinus Torvalds * First it needs to flush existing IO, it does this by sending a magic 635*1da177e4SLinus Torvalds * BIO down the pipe. The completion of this BIO does the actual switch. 636*1da177e4SLinus Torvalds */ 637*1da177e4SLinus Torvalds static int loop_switch(struct loop_device *lo, struct file *file) 638*1da177e4SLinus Torvalds { 639*1da177e4SLinus Torvalds struct switch_request w; 640*1da177e4SLinus Torvalds struct bio *bio = bio_alloc(GFP_KERNEL, 1); 641*1da177e4SLinus Torvalds if (!bio) 642*1da177e4SLinus Torvalds return -ENOMEM; 643*1da177e4SLinus Torvalds init_completion(&w.wait); 644*1da177e4SLinus Torvalds w.file = file; 645*1da177e4SLinus Torvalds bio->bi_private = &w; 646*1da177e4SLinus Torvalds bio->bi_bdev = NULL; 647*1da177e4SLinus Torvalds loop_make_request(lo->lo_queue, bio); 648*1da177e4SLinus Torvalds wait_for_completion(&w.wait); 649*1da177e4SLinus Torvalds return 0; 650*1da177e4SLinus Torvalds } 651*1da177e4SLinus Torvalds 652*1da177e4SLinus Torvalds /* 653*1da177e4SLinus Torvalds * Do the actual switch; called from the BIO completion routine 654*1da177e4SLinus Torvalds */ 655*1da177e4SLinus Torvalds static void do_loop_switch(struct loop_device *lo, struct switch_request *p) 656*1da177e4SLinus Torvalds { 657*1da177e4SLinus Torvalds struct file *file = p->file; 658*1da177e4SLinus Torvalds struct file *old_file = lo->lo_backing_file; 659*1da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 660*1da177e4SLinus Torvalds 661*1da177e4SLinus Torvalds mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); 662*1da177e4SLinus Torvalds lo->lo_backing_file = file; 663*1da177e4SLinus Torvalds lo->lo_blocksize = mapping->host->i_blksize; 664*1da177e4SLinus Torvalds lo->old_gfp_mask = mapping_gfp_mask(mapping); 665*1da177e4SLinus Torvalds mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); 666*1da177e4SLinus Torvalds complete(&p->wait); 667*1da177e4SLinus Torvalds } 668*1da177e4SLinus Torvalds 669*1da177e4SLinus Torvalds 670*1da177e4SLinus Torvalds /* 671*1da177e4SLinus Torvalds * loop_change_fd switched the backing store of a loopback device to 672*1da177e4SLinus Torvalds * a new file. This is useful for operating system installers to free up 673*1da177e4SLinus Torvalds * the original file and in High Availability environments to switch to 674*1da177e4SLinus Torvalds * an alternative location for the content in case of server meltdown. 675*1da177e4SLinus Torvalds * This can only work if the loop device is used read-only, and if the 676*1da177e4SLinus Torvalds * new backing store is the same size and type as the old backing store. 677*1da177e4SLinus Torvalds */ 678*1da177e4SLinus Torvalds static int loop_change_fd(struct loop_device *lo, struct file *lo_file, 679*1da177e4SLinus Torvalds struct block_device *bdev, unsigned int arg) 680*1da177e4SLinus Torvalds { 681*1da177e4SLinus Torvalds struct file *file, *old_file; 682*1da177e4SLinus Torvalds struct inode *inode; 683*1da177e4SLinus Torvalds int error; 684*1da177e4SLinus Torvalds 685*1da177e4SLinus Torvalds error = -ENXIO; 686*1da177e4SLinus Torvalds if (lo->lo_state != Lo_bound) 687*1da177e4SLinus Torvalds goto out; 688*1da177e4SLinus Torvalds 689*1da177e4SLinus Torvalds /* the loop device has to be read-only */ 690*1da177e4SLinus Torvalds error = -EINVAL; 691*1da177e4SLinus Torvalds if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) 692*1da177e4SLinus Torvalds goto out; 693*1da177e4SLinus Torvalds 694*1da177e4SLinus Torvalds error = -EBADF; 695*1da177e4SLinus Torvalds file = fget(arg); 696*1da177e4SLinus Torvalds if (!file) 697*1da177e4SLinus Torvalds goto out; 698*1da177e4SLinus Torvalds 699*1da177e4SLinus Torvalds inode = file->f_mapping->host; 700*1da177e4SLinus Torvalds old_file = lo->lo_backing_file; 701*1da177e4SLinus Torvalds 702*1da177e4SLinus Torvalds error = -EINVAL; 703*1da177e4SLinus Torvalds 704*1da177e4SLinus Torvalds if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) 705*1da177e4SLinus Torvalds goto out_putf; 706*1da177e4SLinus Torvalds 707*1da177e4SLinus Torvalds /* new backing store needs to support loop (eg sendfile) */ 708*1da177e4SLinus Torvalds if (!inode->i_fop->sendfile) 709*1da177e4SLinus Torvalds goto out_putf; 710*1da177e4SLinus Torvalds 711*1da177e4SLinus Torvalds /* size of the new backing store needs to be the same */ 712*1da177e4SLinus Torvalds if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) 713*1da177e4SLinus Torvalds goto out_putf; 714*1da177e4SLinus Torvalds 715*1da177e4SLinus Torvalds /* and ... switch */ 716*1da177e4SLinus Torvalds error = loop_switch(lo, file); 717*1da177e4SLinus Torvalds if (error) 718*1da177e4SLinus Torvalds goto out_putf; 719*1da177e4SLinus Torvalds 720*1da177e4SLinus Torvalds fput(old_file); 721*1da177e4SLinus Torvalds return 0; 722*1da177e4SLinus Torvalds 723*1da177e4SLinus Torvalds out_putf: 724*1da177e4SLinus Torvalds fput(file); 725*1da177e4SLinus Torvalds out: 726*1da177e4SLinus Torvalds return error; 727*1da177e4SLinus Torvalds } 728*1da177e4SLinus Torvalds 729*1da177e4SLinus Torvalds static inline int is_loop_device(struct file *file) 730*1da177e4SLinus Torvalds { 731*1da177e4SLinus Torvalds struct inode *i = file->f_mapping->host; 732*1da177e4SLinus Torvalds 733*1da177e4SLinus Torvalds return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; 734*1da177e4SLinus Torvalds } 735*1da177e4SLinus Torvalds 736*1da177e4SLinus Torvalds static int loop_set_fd(struct loop_device *lo, struct file *lo_file, 737*1da177e4SLinus Torvalds struct block_device *bdev, unsigned int arg) 738*1da177e4SLinus Torvalds { 739*1da177e4SLinus Torvalds struct file *file, *f; 740*1da177e4SLinus Torvalds struct inode *inode; 741*1da177e4SLinus Torvalds struct address_space *mapping; 742*1da177e4SLinus Torvalds unsigned lo_blocksize; 743*1da177e4SLinus Torvalds int lo_flags = 0; 744*1da177e4SLinus Torvalds int error; 745*1da177e4SLinus Torvalds loff_t size; 746*1da177e4SLinus Torvalds 747*1da177e4SLinus Torvalds /* This is safe, since we have a reference from open(). */ 748*1da177e4SLinus Torvalds __module_get(THIS_MODULE); 749*1da177e4SLinus Torvalds 750*1da177e4SLinus Torvalds error = -EBADF; 751*1da177e4SLinus Torvalds file = fget(arg); 752*1da177e4SLinus Torvalds if (!file) 753*1da177e4SLinus Torvalds goto out; 754*1da177e4SLinus Torvalds 755*1da177e4SLinus Torvalds error = -EBUSY; 756*1da177e4SLinus Torvalds if (lo->lo_state != Lo_unbound) 757*1da177e4SLinus Torvalds goto out_putf; 758*1da177e4SLinus Torvalds 759*1da177e4SLinus Torvalds /* Avoid recursion */ 760*1da177e4SLinus Torvalds f = file; 761*1da177e4SLinus Torvalds while (is_loop_device(f)) { 762*1da177e4SLinus Torvalds struct loop_device *l; 763*1da177e4SLinus Torvalds 764*1da177e4SLinus Torvalds if (f->f_mapping->host->i_rdev == lo_file->f_mapping->host->i_rdev) 765*1da177e4SLinus Torvalds goto out_putf; 766*1da177e4SLinus Torvalds 767*1da177e4SLinus Torvalds l = f->f_mapping->host->i_bdev->bd_disk->private_data; 768*1da177e4SLinus Torvalds if (l->lo_state == Lo_unbound) { 769*1da177e4SLinus Torvalds error = -EINVAL; 770*1da177e4SLinus Torvalds goto out_putf; 771*1da177e4SLinus Torvalds } 772*1da177e4SLinus Torvalds f = l->lo_backing_file; 773*1da177e4SLinus Torvalds } 774*1da177e4SLinus Torvalds 775*1da177e4SLinus Torvalds mapping = file->f_mapping; 776*1da177e4SLinus Torvalds inode = mapping->host; 777*1da177e4SLinus Torvalds 778*1da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 779*1da177e4SLinus Torvalds lo_flags |= LO_FLAGS_READ_ONLY; 780*1da177e4SLinus Torvalds 781*1da177e4SLinus Torvalds error = -EINVAL; 782*1da177e4SLinus Torvalds if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) { 783*1da177e4SLinus Torvalds struct address_space_operations *aops = mapping->a_ops; 784*1da177e4SLinus Torvalds /* 785*1da177e4SLinus Torvalds * If we can't read - sorry. If we only can't write - well, 786*1da177e4SLinus Torvalds * it's going to be read-only. 787*1da177e4SLinus Torvalds */ 788*1da177e4SLinus Torvalds if (!file->f_op->sendfile) 789*1da177e4SLinus Torvalds goto out_putf; 790*1da177e4SLinus Torvalds if (aops->prepare_write && aops->commit_write) 791*1da177e4SLinus Torvalds lo_flags |= LO_FLAGS_USE_AOPS; 792*1da177e4SLinus Torvalds if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write) 793*1da177e4SLinus Torvalds lo_flags |= LO_FLAGS_READ_ONLY; 794*1da177e4SLinus Torvalds 795*1da177e4SLinus Torvalds lo_blocksize = inode->i_blksize; 796*1da177e4SLinus Torvalds error = 0; 797*1da177e4SLinus Torvalds } else { 798*1da177e4SLinus Torvalds goto out_putf; 799*1da177e4SLinus Torvalds } 800*1da177e4SLinus Torvalds 801*1da177e4SLinus Torvalds size = get_loop_size(lo, file); 802*1da177e4SLinus Torvalds 803*1da177e4SLinus Torvalds if ((loff_t)(sector_t)size != size) { 804*1da177e4SLinus Torvalds error = -EFBIG; 805*1da177e4SLinus Torvalds goto out_putf; 806*1da177e4SLinus Torvalds } 807*1da177e4SLinus Torvalds 808*1da177e4SLinus Torvalds if (!(lo_file->f_mode & FMODE_WRITE)) 809*1da177e4SLinus Torvalds lo_flags |= LO_FLAGS_READ_ONLY; 810*1da177e4SLinus Torvalds 811*1da177e4SLinus Torvalds set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); 812*1da177e4SLinus Torvalds 813*1da177e4SLinus Torvalds lo->lo_blocksize = lo_blocksize; 814*1da177e4SLinus Torvalds lo->lo_device = bdev; 815*1da177e4SLinus Torvalds lo->lo_flags = lo_flags; 816*1da177e4SLinus Torvalds lo->lo_backing_file = file; 817*1da177e4SLinus Torvalds lo->transfer = NULL; 818*1da177e4SLinus Torvalds lo->ioctl = NULL; 819*1da177e4SLinus Torvalds lo->lo_sizelimit = 0; 820*1da177e4SLinus Torvalds lo->old_gfp_mask = mapping_gfp_mask(mapping); 821*1da177e4SLinus Torvalds mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); 822*1da177e4SLinus Torvalds 823*1da177e4SLinus Torvalds lo->lo_bio = lo->lo_biotail = NULL; 824*1da177e4SLinus Torvalds 825*1da177e4SLinus Torvalds /* 826*1da177e4SLinus Torvalds * set queue make_request_fn, and add limits based on lower level 827*1da177e4SLinus Torvalds * device 828*1da177e4SLinus Torvalds */ 829*1da177e4SLinus Torvalds blk_queue_make_request(lo->lo_queue, loop_make_request); 830*1da177e4SLinus Torvalds lo->lo_queue->queuedata = lo; 831*1da177e4SLinus Torvalds lo->lo_queue->unplug_fn = loop_unplug; 832*1da177e4SLinus Torvalds 833*1da177e4SLinus Torvalds set_capacity(disks[lo->lo_number], size); 834*1da177e4SLinus Torvalds bd_set_size(bdev, size << 9); 835*1da177e4SLinus Torvalds 836*1da177e4SLinus Torvalds set_blocksize(bdev, lo_blocksize); 837*1da177e4SLinus Torvalds 838*1da177e4SLinus Torvalds kernel_thread(loop_thread, lo, CLONE_KERNEL); 839*1da177e4SLinus Torvalds down(&lo->lo_sem); 840*1da177e4SLinus Torvalds return 0; 841*1da177e4SLinus Torvalds 842*1da177e4SLinus Torvalds out_putf: 843*1da177e4SLinus Torvalds fput(file); 844*1da177e4SLinus Torvalds out: 845*1da177e4SLinus Torvalds /* This is safe: open() is still holding a reference. */ 846*1da177e4SLinus Torvalds module_put(THIS_MODULE); 847*1da177e4SLinus Torvalds return error; 848*1da177e4SLinus Torvalds } 849*1da177e4SLinus Torvalds 850*1da177e4SLinus Torvalds static int 851*1da177e4SLinus Torvalds loop_release_xfer(struct loop_device *lo) 852*1da177e4SLinus Torvalds { 853*1da177e4SLinus Torvalds int err = 0; 854*1da177e4SLinus Torvalds struct loop_func_table *xfer = lo->lo_encryption; 855*1da177e4SLinus Torvalds 856*1da177e4SLinus Torvalds if (xfer) { 857*1da177e4SLinus Torvalds if (xfer->release) 858*1da177e4SLinus Torvalds err = xfer->release(lo); 859*1da177e4SLinus Torvalds lo->transfer = NULL; 860*1da177e4SLinus Torvalds lo->lo_encryption = NULL; 861*1da177e4SLinus Torvalds module_put(xfer->owner); 862*1da177e4SLinus Torvalds } 863*1da177e4SLinus Torvalds return err; 864*1da177e4SLinus Torvalds } 865*1da177e4SLinus Torvalds 866*1da177e4SLinus Torvalds static int 867*1da177e4SLinus Torvalds loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, 868*1da177e4SLinus Torvalds const struct loop_info64 *i) 869*1da177e4SLinus Torvalds { 870*1da177e4SLinus Torvalds int err = 0; 871*1da177e4SLinus Torvalds 872*1da177e4SLinus Torvalds if (xfer) { 873*1da177e4SLinus Torvalds struct module *owner = xfer->owner; 874*1da177e4SLinus Torvalds 875*1da177e4SLinus Torvalds if (!try_module_get(owner)) 876*1da177e4SLinus Torvalds return -EINVAL; 877*1da177e4SLinus Torvalds if (xfer->init) 878*1da177e4SLinus Torvalds err = xfer->init(lo, i); 879*1da177e4SLinus Torvalds if (err) 880*1da177e4SLinus Torvalds module_put(owner); 881*1da177e4SLinus Torvalds else 882*1da177e4SLinus Torvalds lo->lo_encryption = xfer; 883*1da177e4SLinus Torvalds } 884*1da177e4SLinus Torvalds return err; 885*1da177e4SLinus Torvalds } 886*1da177e4SLinus Torvalds 887*1da177e4SLinus Torvalds static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) 888*1da177e4SLinus Torvalds { 889*1da177e4SLinus Torvalds struct file *filp = lo->lo_backing_file; 890*1da177e4SLinus Torvalds int gfp = lo->old_gfp_mask; 891*1da177e4SLinus Torvalds 892*1da177e4SLinus Torvalds if (lo->lo_state != Lo_bound) 893*1da177e4SLinus Torvalds return -ENXIO; 894*1da177e4SLinus Torvalds 895*1da177e4SLinus Torvalds if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */ 896*1da177e4SLinus Torvalds return -EBUSY; 897*1da177e4SLinus Torvalds 898*1da177e4SLinus Torvalds if (filp == NULL) 899*1da177e4SLinus Torvalds return -EINVAL; 900*1da177e4SLinus Torvalds 901*1da177e4SLinus Torvalds spin_lock_irq(&lo->lo_lock); 902*1da177e4SLinus Torvalds lo->lo_state = Lo_rundown; 903*1da177e4SLinus Torvalds if (atomic_dec_and_test(&lo->lo_pending)) 904*1da177e4SLinus Torvalds up(&lo->lo_bh_mutex); 905*1da177e4SLinus Torvalds spin_unlock_irq(&lo->lo_lock); 906*1da177e4SLinus Torvalds 907*1da177e4SLinus Torvalds down(&lo->lo_sem); 908*1da177e4SLinus Torvalds 909*1da177e4SLinus Torvalds lo->lo_backing_file = NULL; 910*1da177e4SLinus Torvalds 911*1da177e4SLinus Torvalds loop_release_xfer(lo); 912*1da177e4SLinus Torvalds lo->transfer = NULL; 913*1da177e4SLinus Torvalds lo->ioctl = NULL; 914*1da177e4SLinus Torvalds lo->lo_device = NULL; 915*1da177e4SLinus Torvalds lo->lo_encryption = NULL; 916*1da177e4SLinus Torvalds lo->lo_offset = 0; 917*1da177e4SLinus Torvalds lo->lo_sizelimit = 0; 918*1da177e4SLinus Torvalds lo->lo_encrypt_key_size = 0; 919*1da177e4SLinus Torvalds lo->lo_flags = 0; 920*1da177e4SLinus Torvalds memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); 921*1da177e4SLinus Torvalds memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); 922*1da177e4SLinus Torvalds memset(lo->lo_file_name, 0, LO_NAME_SIZE); 923*1da177e4SLinus Torvalds invalidate_bdev(bdev, 0); 924*1da177e4SLinus Torvalds set_capacity(disks[lo->lo_number], 0); 925*1da177e4SLinus Torvalds bd_set_size(bdev, 0); 926*1da177e4SLinus Torvalds mapping_set_gfp_mask(filp->f_mapping, gfp); 927*1da177e4SLinus Torvalds lo->lo_state = Lo_unbound; 928*1da177e4SLinus Torvalds fput(filp); 929*1da177e4SLinus Torvalds /* This is safe: open() is still holding a reference. */ 930*1da177e4SLinus Torvalds module_put(THIS_MODULE); 931*1da177e4SLinus Torvalds return 0; 932*1da177e4SLinus Torvalds } 933*1da177e4SLinus Torvalds 934*1da177e4SLinus Torvalds static int 935*1da177e4SLinus Torvalds loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 936*1da177e4SLinus Torvalds { 937*1da177e4SLinus Torvalds int err; 938*1da177e4SLinus Torvalds struct loop_func_table *xfer; 939*1da177e4SLinus Torvalds 940*1da177e4SLinus Torvalds if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid && 941*1da177e4SLinus Torvalds !capable(CAP_SYS_ADMIN)) 942*1da177e4SLinus Torvalds return -EPERM; 943*1da177e4SLinus Torvalds if (lo->lo_state != Lo_bound) 944*1da177e4SLinus Torvalds return -ENXIO; 945*1da177e4SLinus Torvalds if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) 946*1da177e4SLinus Torvalds return -EINVAL; 947*1da177e4SLinus Torvalds 948*1da177e4SLinus Torvalds err = loop_release_xfer(lo); 949*1da177e4SLinus Torvalds if (err) 950*1da177e4SLinus Torvalds return err; 951*1da177e4SLinus Torvalds 952*1da177e4SLinus Torvalds if (info->lo_encrypt_type) { 953*1da177e4SLinus Torvalds unsigned int type = info->lo_encrypt_type; 954*1da177e4SLinus Torvalds 955*1da177e4SLinus Torvalds if (type >= MAX_LO_CRYPT) 956*1da177e4SLinus Torvalds return -EINVAL; 957*1da177e4SLinus Torvalds xfer = xfer_funcs[type]; 958*1da177e4SLinus Torvalds if (xfer == NULL) 959*1da177e4SLinus Torvalds return -EINVAL; 960*1da177e4SLinus Torvalds } else 961*1da177e4SLinus Torvalds xfer = NULL; 962*1da177e4SLinus Torvalds 963*1da177e4SLinus Torvalds err = loop_init_xfer(lo, xfer, info); 964*1da177e4SLinus Torvalds if (err) 965*1da177e4SLinus Torvalds return err; 966*1da177e4SLinus Torvalds 967*1da177e4SLinus Torvalds if (lo->lo_offset != info->lo_offset || 968*1da177e4SLinus Torvalds lo->lo_sizelimit != info->lo_sizelimit) { 969*1da177e4SLinus Torvalds lo->lo_offset = info->lo_offset; 970*1da177e4SLinus Torvalds lo->lo_sizelimit = info->lo_sizelimit; 971*1da177e4SLinus Torvalds if (figure_loop_size(lo)) 972*1da177e4SLinus Torvalds return -EFBIG; 973*1da177e4SLinus Torvalds } 974*1da177e4SLinus Torvalds 975*1da177e4SLinus Torvalds memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); 976*1da177e4SLinus Torvalds memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); 977*1da177e4SLinus Torvalds lo->lo_file_name[LO_NAME_SIZE-1] = 0; 978*1da177e4SLinus Torvalds lo->lo_crypt_name[LO_NAME_SIZE-1] = 0; 979*1da177e4SLinus Torvalds 980*1da177e4SLinus Torvalds if (!xfer) 981*1da177e4SLinus Torvalds xfer = &none_funcs; 982*1da177e4SLinus Torvalds lo->transfer = xfer->transfer; 983*1da177e4SLinus Torvalds lo->ioctl = xfer->ioctl; 984*1da177e4SLinus Torvalds 985*1da177e4SLinus Torvalds lo->lo_encrypt_key_size = info->lo_encrypt_key_size; 986*1da177e4SLinus Torvalds lo->lo_init[0] = info->lo_init[0]; 987*1da177e4SLinus Torvalds lo->lo_init[1] = info->lo_init[1]; 988*1da177e4SLinus Torvalds if (info->lo_encrypt_key_size) { 989*1da177e4SLinus Torvalds memcpy(lo->lo_encrypt_key, info->lo_encrypt_key, 990*1da177e4SLinus Torvalds info->lo_encrypt_key_size); 991*1da177e4SLinus Torvalds lo->lo_key_owner = current->uid; 992*1da177e4SLinus Torvalds } 993*1da177e4SLinus Torvalds 994*1da177e4SLinus Torvalds return 0; 995*1da177e4SLinus Torvalds } 996*1da177e4SLinus Torvalds 997*1da177e4SLinus Torvalds static int 998*1da177e4SLinus Torvalds loop_get_status(struct loop_device *lo, struct loop_info64 *info) 999*1da177e4SLinus Torvalds { 1000*1da177e4SLinus Torvalds struct file *file = lo->lo_backing_file; 1001*1da177e4SLinus Torvalds struct kstat stat; 1002*1da177e4SLinus Torvalds int error; 1003*1da177e4SLinus Torvalds 1004*1da177e4SLinus Torvalds if (lo->lo_state != Lo_bound) 1005*1da177e4SLinus Torvalds return -ENXIO; 1006*1da177e4SLinus Torvalds error = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat); 1007*1da177e4SLinus Torvalds if (error) 1008*1da177e4SLinus Torvalds return error; 1009*1da177e4SLinus Torvalds memset(info, 0, sizeof(*info)); 1010*1da177e4SLinus Torvalds info->lo_number = lo->lo_number; 1011*1da177e4SLinus Torvalds info->lo_device = huge_encode_dev(stat.dev); 1012*1da177e4SLinus Torvalds info->lo_inode = stat.ino; 1013*1da177e4SLinus Torvalds info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev); 1014*1da177e4SLinus Torvalds info->lo_offset = lo->lo_offset; 1015*1da177e4SLinus Torvalds info->lo_sizelimit = lo->lo_sizelimit; 1016*1da177e4SLinus Torvalds info->lo_flags = lo->lo_flags; 1017*1da177e4SLinus Torvalds memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE); 1018*1da177e4SLinus Torvalds memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE); 1019*1da177e4SLinus Torvalds info->lo_encrypt_type = 1020*1da177e4SLinus Torvalds lo->lo_encryption ? lo->lo_encryption->number : 0; 1021*1da177e4SLinus Torvalds if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { 1022*1da177e4SLinus Torvalds info->lo_encrypt_key_size = lo->lo_encrypt_key_size; 1023*1da177e4SLinus Torvalds memcpy(info->lo_encrypt_key, lo->lo_encrypt_key, 1024*1da177e4SLinus Torvalds lo->lo_encrypt_key_size); 1025*1da177e4SLinus Torvalds } 1026*1da177e4SLinus Torvalds return 0; 1027*1da177e4SLinus Torvalds } 1028*1da177e4SLinus Torvalds 1029*1da177e4SLinus Torvalds static void 1030*1da177e4SLinus Torvalds loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64) 1031*1da177e4SLinus Torvalds { 1032*1da177e4SLinus Torvalds memset(info64, 0, sizeof(*info64)); 1033*1da177e4SLinus Torvalds info64->lo_number = info->lo_number; 1034*1da177e4SLinus Torvalds info64->lo_device = info->lo_device; 1035*1da177e4SLinus Torvalds info64->lo_inode = info->lo_inode; 1036*1da177e4SLinus Torvalds info64->lo_rdevice = info->lo_rdevice; 1037*1da177e4SLinus Torvalds info64->lo_offset = info->lo_offset; 1038*1da177e4SLinus Torvalds info64->lo_sizelimit = 0; 1039*1da177e4SLinus Torvalds info64->lo_encrypt_type = info->lo_encrypt_type; 1040*1da177e4SLinus Torvalds info64->lo_encrypt_key_size = info->lo_encrypt_key_size; 1041*1da177e4SLinus Torvalds info64->lo_flags = info->lo_flags; 1042*1da177e4SLinus Torvalds info64->lo_init[0] = info->lo_init[0]; 1043*1da177e4SLinus Torvalds info64->lo_init[1] = info->lo_init[1]; 1044*1da177e4SLinus Torvalds if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) 1045*1da177e4SLinus Torvalds memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE); 1046*1da177e4SLinus Torvalds else 1047*1da177e4SLinus Torvalds memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE); 1048*1da177e4SLinus Torvalds memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE); 1049*1da177e4SLinus Torvalds } 1050*1da177e4SLinus Torvalds 1051*1da177e4SLinus Torvalds static int 1052*1da177e4SLinus Torvalds loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info) 1053*1da177e4SLinus Torvalds { 1054*1da177e4SLinus Torvalds memset(info, 0, sizeof(*info)); 1055*1da177e4SLinus Torvalds info->lo_number = info64->lo_number; 1056*1da177e4SLinus Torvalds info->lo_device = info64->lo_device; 1057*1da177e4SLinus Torvalds info->lo_inode = info64->lo_inode; 1058*1da177e4SLinus Torvalds info->lo_rdevice = info64->lo_rdevice; 1059*1da177e4SLinus Torvalds info->lo_offset = info64->lo_offset; 1060*1da177e4SLinus Torvalds info->lo_encrypt_type = info64->lo_encrypt_type; 1061*1da177e4SLinus Torvalds info->lo_encrypt_key_size = info64->lo_encrypt_key_size; 1062*1da177e4SLinus Torvalds info->lo_flags = info64->lo_flags; 1063*1da177e4SLinus Torvalds info->lo_init[0] = info64->lo_init[0]; 1064*1da177e4SLinus Torvalds info->lo_init[1] = info64->lo_init[1]; 1065*1da177e4SLinus Torvalds if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI) 1066*1da177e4SLinus Torvalds memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE); 1067*1da177e4SLinus Torvalds else 1068*1da177e4SLinus Torvalds memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE); 1069*1da177e4SLinus Torvalds memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE); 1070*1da177e4SLinus Torvalds 1071*1da177e4SLinus Torvalds /* error in case values were truncated */ 1072*1da177e4SLinus Torvalds if (info->lo_device != info64->lo_device || 1073*1da177e4SLinus Torvalds info->lo_rdevice != info64->lo_rdevice || 1074*1da177e4SLinus Torvalds info->lo_inode != info64->lo_inode || 1075*1da177e4SLinus Torvalds info->lo_offset != info64->lo_offset) 1076*1da177e4SLinus Torvalds return -EOVERFLOW; 1077*1da177e4SLinus Torvalds 1078*1da177e4SLinus Torvalds return 0; 1079*1da177e4SLinus Torvalds } 1080*1da177e4SLinus Torvalds 1081*1da177e4SLinus Torvalds static int 1082*1da177e4SLinus Torvalds loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg) 1083*1da177e4SLinus Torvalds { 1084*1da177e4SLinus Torvalds struct loop_info info; 1085*1da177e4SLinus Torvalds struct loop_info64 info64; 1086*1da177e4SLinus Torvalds 1087*1da177e4SLinus Torvalds if (copy_from_user(&info, arg, sizeof (struct loop_info))) 1088*1da177e4SLinus Torvalds return -EFAULT; 1089*1da177e4SLinus Torvalds loop_info64_from_old(&info, &info64); 1090*1da177e4SLinus Torvalds return loop_set_status(lo, &info64); 1091*1da177e4SLinus Torvalds } 1092*1da177e4SLinus Torvalds 1093*1da177e4SLinus Torvalds static int 1094*1da177e4SLinus Torvalds loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg) 1095*1da177e4SLinus Torvalds { 1096*1da177e4SLinus Torvalds struct loop_info64 info64; 1097*1da177e4SLinus Torvalds 1098*1da177e4SLinus Torvalds if (copy_from_user(&info64, arg, sizeof (struct loop_info64))) 1099*1da177e4SLinus Torvalds return -EFAULT; 1100*1da177e4SLinus Torvalds return loop_set_status(lo, &info64); 1101*1da177e4SLinus Torvalds } 1102*1da177e4SLinus Torvalds 1103*1da177e4SLinus Torvalds static int 1104*1da177e4SLinus Torvalds loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { 1105*1da177e4SLinus Torvalds struct loop_info info; 1106*1da177e4SLinus Torvalds struct loop_info64 info64; 1107*1da177e4SLinus Torvalds int err = 0; 1108*1da177e4SLinus Torvalds 1109*1da177e4SLinus Torvalds if (!arg) 1110*1da177e4SLinus Torvalds err = -EINVAL; 1111*1da177e4SLinus Torvalds if (!err) 1112*1da177e4SLinus Torvalds err = loop_get_status(lo, &info64); 1113*1da177e4SLinus Torvalds if (!err) 1114*1da177e4SLinus Torvalds err = loop_info64_to_old(&info64, &info); 1115*1da177e4SLinus Torvalds if (!err && copy_to_user(arg, &info, sizeof(info))) 1116*1da177e4SLinus Torvalds err = -EFAULT; 1117*1da177e4SLinus Torvalds 1118*1da177e4SLinus Torvalds return err; 1119*1da177e4SLinus Torvalds } 1120*1da177e4SLinus Torvalds 1121*1da177e4SLinus Torvalds static int 1122*1da177e4SLinus Torvalds loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { 1123*1da177e4SLinus Torvalds struct loop_info64 info64; 1124*1da177e4SLinus Torvalds int err = 0; 1125*1da177e4SLinus Torvalds 1126*1da177e4SLinus Torvalds if (!arg) 1127*1da177e4SLinus Torvalds err = -EINVAL; 1128*1da177e4SLinus Torvalds if (!err) 1129*1da177e4SLinus Torvalds err = loop_get_status(lo, &info64); 1130*1da177e4SLinus Torvalds if (!err && copy_to_user(arg, &info64, sizeof(info64))) 1131*1da177e4SLinus Torvalds err = -EFAULT; 1132*1da177e4SLinus Torvalds 1133*1da177e4SLinus Torvalds return err; 1134*1da177e4SLinus Torvalds } 1135*1da177e4SLinus Torvalds 1136*1da177e4SLinus Torvalds static int lo_ioctl(struct inode * inode, struct file * file, 1137*1da177e4SLinus Torvalds unsigned int cmd, unsigned long arg) 1138*1da177e4SLinus Torvalds { 1139*1da177e4SLinus Torvalds struct loop_device *lo = inode->i_bdev->bd_disk->private_data; 1140*1da177e4SLinus Torvalds int err; 1141*1da177e4SLinus Torvalds 1142*1da177e4SLinus Torvalds down(&lo->lo_ctl_mutex); 1143*1da177e4SLinus Torvalds switch (cmd) { 1144*1da177e4SLinus Torvalds case LOOP_SET_FD: 1145*1da177e4SLinus Torvalds err = loop_set_fd(lo, file, inode->i_bdev, arg); 1146*1da177e4SLinus Torvalds break; 1147*1da177e4SLinus Torvalds case LOOP_CHANGE_FD: 1148*1da177e4SLinus Torvalds err = loop_change_fd(lo, file, inode->i_bdev, arg); 1149*1da177e4SLinus Torvalds break; 1150*1da177e4SLinus Torvalds case LOOP_CLR_FD: 1151*1da177e4SLinus Torvalds err = loop_clr_fd(lo, inode->i_bdev); 1152*1da177e4SLinus Torvalds break; 1153*1da177e4SLinus Torvalds case LOOP_SET_STATUS: 1154*1da177e4SLinus Torvalds err = loop_set_status_old(lo, (struct loop_info __user *) arg); 1155*1da177e4SLinus Torvalds break; 1156*1da177e4SLinus Torvalds case LOOP_GET_STATUS: 1157*1da177e4SLinus Torvalds err = loop_get_status_old(lo, (struct loop_info __user *) arg); 1158*1da177e4SLinus Torvalds break; 1159*1da177e4SLinus Torvalds case LOOP_SET_STATUS64: 1160*1da177e4SLinus Torvalds err = loop_set_status64(lo, (struct loop_info64 __user *) arg); 1161*1da177e4SLinus Torvalds break; 1162*1da177e4SLinus Torvalds case LOOP_GET_STATUS64: 1163*1da177e4SLinus Torvalds err = loop_get_status64(lo, (struct loop_info64 __user *) arg); 1164*1da177e4SLinus Torvalds break; 1165*1da177e4SLinus Torvalds default: 1166*1da177e4SLinus Torvalds err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; 1167*1da177e4SLinus Torvalds } 1168*1da177e4SLinus Torvalds up(&lo->lo_ctl_mutex); 1169*1da177e4SLinus Torvalds return err; 1170*1da177e4SLinus Torvalds } 1171*1da177e4SLinus Torvalds 1172*1da177e4SLinus Torvalds static int lo_open(struct inode *inode, struct file *file) 1173*1da177e4SLinus Torvalds { 1174*1da177e4SLinus Torvalds struct loop_device *lo = inode->i_bdev->bd_disk->private_data; 1175*1da177e4SLinus Torvalds 1176*1da177e4SLinus Torvalds down(&lo->lo_ctl_mutex); 1177*1da177e4SLinus Torvalds lo->lo_refcnt++; 1178*1da177e4SLinus Torvalds up(&lo->lo_ctl_mutex); 1179*1da177e4SLinus Torvalds 1180*1da177e4SLinus Torvalds return 0; 1181*1da177e4SLinus Torvalds } 1182*1da177e4SLinus Torvalds 1183*1da177e4SLinus Torvalds static int lo_release(struct inode *inode, struct file *file) 1184*1da177e4SLinus Torvalds { 1185*1da177e4SLinus Torvalds struct loop_device *lo = inode->i_bdev->bd_disk->private_data; 1186*1da177e4SLinus Torvalds 1187*1da177e4SLinus Torvalds down(&lo->lo_ctl_mutex); 1188*1da177e4SLinus Torvalds --lo->lo_refcnt; 1189*1da177e4SLinus Torvalds up(&lo->lo_ctl_mutex); 1190*1da177e4SLinus Torvalds 1191*1da177e4SLinus Torvalds return 0; 1192*1da177e4SLinus Torvalds } 1193*1da177e4SLinus Torvalds 1194*1da177e4SLinus Torvalds static struct block_device_operations lo_fops = { 1195*1da177e4SLinus Torvalds .owner = THIS_MODULE, 1196*1da177e4SLinus Torvalds .open = lo_open, 1197*1da177e4SLinus Torvalds .release = lo_release, 1198*1da177e4SLinus Torvalds .ioctl = lo_ioctl, 1199*1da177e4SLinus Torvalds }; 1200*1da177e4SLinus Torvalds 1201*1da177e4SLinus Torvalds /* 1202*1da177e4SLinus Torvalds * And now the modules code and kernel interface. 1203*1da177e4SLinus Torvalds */ 1204*1da177e4SLinus Torvalds module_param(max_loop, int, 0); 1205*1da177e4SLinus Torvalds MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)"); 1206*1da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1207*1da177e4SLinus Torvalds MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); 1208*1da177e4SLinus Torvalds 1209*1da177e4SLinus Torvalds int loop_register_transfer(struct loop_func_table *funcs) 1210*1da177e4SLinus Torvalds { 1211*1da177e4SLinus Torvalds unsigned int n = funcs->number; 1212*1da177e4SLinus Torvalds 1213*1da177e4SLinus Torvalds if (n >= MAX_LO_CRYPT || xfer_funcs[n]) 1214*1da177e4SLinus Torvalds return -EINVAL; 1215*1da177e4SLinus Torvalds xfer_funcs[n] = funcs; 1216*1da177e4SLinus Torvalds return 0; 1217*1da177e4SLinus Torvalds } 1218*1da177e4SLinus Torvalds 1219*1da177e4SLinus Torvalds int loop_unregister_transfer(int number) 1220*1da177e4SLinus Torvalds { 1221*1da177e4SLinus Torvalds unsigned int n = number; 1222*1da177e4SLinus Torvalds struct loop_device *lo; 1223*1da177e4SLinus Torvalds struct loop_func_table *xfer; 1224*1da177e4SLinus Torvalds 1225*1da177e4SLinus Torvalds if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL) 1226*1da177e4SLinus Torvalds return -EINVAL; 1227*1da177e4SLinus Torvalds 1228*1da177e4SLinus Torvalds xfer_funcs[n] = NULL; 1229*1da177e4SLinus Torvalds 1230*1da177e4SLinus Torvalds for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) { 1231*1da177e4SLinus Torvalds down(&lo->lo_ctl_mutex); 1232*1da177e4SLinus Torvalds 1233*1da177e4SLinus Torvalds if (lo->lo_encryption == xfer) 1234*1da177e4SLinus Torvalds loop_release_xfer(lo); 1235*1da177e4SLinus Torvalds 1236*1da177e4SLinus Torvalds up(&lo->lo_ctl_mutex); 1237*1da177e4SLinus Torvalds } 1238*1da177e4SLinus Torvalds 1239*1da177e4SLinus Torvalds return 0; 1240*1da177e4SLinus Torvalds } 1241*1da177e4SLinus Torvalds 1242*1da177e4SLinus Torvalds EXPORT_SYMBOL(loop_register_transfer); 1243*1da177e4SLinus Torvalds EXPORT_SYMBOL(loop_unregister_transfer); 1244*1da177e4SLinus Torvalds 1245*1da177e4SLinus Torvalds static int __init loop_init(void) 1246*1da177e4SLinus Torvalds { 1247*1da177e4SLinus Torvalds int i; 1248*1da177e4SLinus Torvalds 1249*1da177e4SLinus Torvalds if (max_loop < 1 || max_loop > 256) { 1250*1da177e4SLinus Torvalds printk(KERN_WARNING "loop: invalid max_loop (must be between" 1251*1da177e4SLinus Torvalds " 1 and 256), using default (8)\n"); 1252*1da177e4SLinus Torvalds max_loop = 8; 1253*1da177e4SLinus Torvalds } 1254*1da177e4SLinus Torvalds 1255*1da177e4SLinus Torvalds if (register_blkdev(LOOP_MAJOR, "loop")) 1256*1da177e4SLinus Torvalds return -EIO; 1257*1da177e4SLinus Torvalds 1258*1da177e4SLinus Torvalds loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL); 1259*1da177e4SLinus Torvalds if (!loop_dev) 1260*1da177e4SLinus Torvalds goto out_mem1; 1261*1da177e4SLinus Torvalds memset(loop_dev, 0, max_loop * sizeof(struct loop_device)); 1262*1da177e4SLinus Torvalds 1263*1da177e4SLinus Torvalds disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL); 1264*1da177e4SLinus Torvalds if (!disks) 1265*1da177e4SLinus Torvalds goto out_mem2; 1266*1da177e4SLinus Torvalds 1267*1da177e4SLinus Torvalds for (i = 0; i < max_loop; i++) { 1268*1da177e4SLinus Torvalds disks[i] = alloc_disk(1); 1269*1da177e4SLinus Torvalds if (!disks[i]) 1270*1da177e4SLinus Torvalds goto out_mem3; 1271*1da177e4SLinus Torvalds } 1272*1da177e4SLinus Torvalds 1273*1da177e4SLinus Torvalds devfs_mk_dir("loop"); 1274*1da177e4SLinus Torvalds 1275*1da177e4SLinus Torvalds for (i = 0; i < max_loop; i++) { 1276*1da177e4SLinus Torvalds struct loop_device *lo = &loop_dev[i]; 1277*1da177e4SLinus Torvalds struct gendisk *disk = disks[i]; 1278*1da177e4SLinus Torvalds 1279*1da177e4SLinus Torvalds memset(lo, 0, sizeof(*lo)); 1280*1da177e4SLinus Torvalds lo->lo_queue = blk_alloc_queue(GFP_KERNEL); 1281*1da177e4SLinus Torvalds if (!lo->lo_queue) 1282*1da177e4SLinus Torvalds goto out_mem4; 1283*1da177e4SLinus Torvalds init_MUTEX(&lo->lo_ctl_mutex); 1284*1da177e4SLinus Torvalds init_MUTEX_LOCKED(&lo->lo_sem); 1285*1da177e4SLinus Torvalds init_MUTEX_LOCKED(&lo->lo_bh_mutex); 1286*1da177e4SLinus Torvalds lo->lo_number = i; 1287*1da177e4SLinus Torvalds spin_lock_init(&lo->lo_lock); 1288*1da177e4SLinus Torvalds disk->major = LOOP_MAJOR; 1289*1da177e4SLinus Torvalds disk->first_minor = i; 1290*1da177e4SLinus Torvalds disk->fops = &lo_fops; 1291*1da177e4SLinus Torvalds sprintf(disk->disk_name, "loop%d", i); 1292*1da177e4SLinus Torvalds sprintf(disk->devfs_name, "loop/%d", i); 1293*1da177e4SLinus Torvalds disk->private_data = lo; 1294*1da177e4SLinus Torvalds disk->queue = lo->lo_queue; 1295*1da177e4SLinus Torvalds } 1296*1da177e4SLinus Torvalds 1297*1da177e4SLinus Torvalds /* We cannot fail after we call this, so another loop!*/ 1298*1da177e4SLinus Torvalds for (i = 0; i < max_loop; i++) 1299*1da177e4SLinus Torvalds add_disk(disks[i]); 1300*1da177e4SLinus Torvalds printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop); 1301*1da177e4SLinus Torvalds return 0; 1302*1da177e4SLinus Torvalds 1303*1da177e4SLinus Torvalds out_mem4: 1304*1da177e4SLinus Torvalds while (i--) 1305*1da177e4SLinus Torvalds blk_put_queue(loop_dev[i].lo_queue); 1306*1da177e4SLinus Torvalds devfs_remove("loop"); 1307*1da177e4SLinus Torvalds i = max_loop; 1308*1da177e4SLinus Torvalds out_mem3: 1309*1da177e4SLinus Torvalds while (i--) 1310*1da177e4SLinus Torvalds put_disk(disks[i]); 1311*1da177e4SLinus Torvalds kfree(disks); 1312*1da177e4SLinus Torvalds out_mem2: 1313*1da177e4SLinus Torvalds kfree(loop_dev); 1314*1da177e4SLinus Torvalds out_mem1: 1315*1da177e4SLinus Torvalds unregister_blkdev(LOOP_MAJOR, "loop"); 1316*1da177e4SLinus Torvalds printk(KERN_ERR "loop: ran out of memory\n"); 1317*1da177e4SLinus Torvalds return -ENOMEM; 1318*1da177e4SLinus Torvalds } 1319*1da177e4SLinus Torvalds 1320*1da177e4SLinus Torvalds static void loop_exit(void) 1321*1da177e4SLinus Torvalds { 1322*1da177e4SLinus Torvalds int i; 1323*1da177e4SLinus Torvalds 1324*1da177e4SLinus Torvalds for (i = 0; i < max_loop; i++) { 1325*1da177e4SLinus Torvalds del_gendisk(disks[i]); 1326*1da177e4SLinus Torvalds blk_put_queue(loop_dev[i].lo_queue); 1327*1da177e4SLinus Torvalds put_disk(disks[i]); 1328*1da177e4SLinus Torvalds } 1329*1da177e4SLinus Torvalds devfs_remove("loop"); 1330*1da177e4SLinus Torvalds if (unregister_blkdev(LOOP_MAJOR, "loop")) 1331*1da177e4SLinus Torvalds printk(KERN_WARNING "loop: cannot unregister blkdev\n"); 1332*1da177e4SLinus Torvalds 1333*1da177e4SLinus Torvalds kfree(disks); 1334*1da177e4SLinus Torvalds kfree(loop_dev); 1335*1da177e4SLinus Torvalds } 1336*1da177e4SLinus Torvalds 1337*1da177e4SLinus Torvalds module_init(loop_init); 1338*1da177e4SLinus Torvalds module_exit(loop_exit); 1339*1da177e4SLinus Torvalds 1340*1da177e4SLinus Torvalds #ifndef MODULE 1341*1da177e4SLinus Torvalds static int __init max_loop_setup(char *str) 1342*1da177e4SLinus Torvalds { 1343*1da177e4SLinus Torvalds max_loop = simple_strtol(str, NULL, 0); 1344*1da177e4SLinus Torvalds return 1; 1345*1da177e4SLinus Torvalds } 1346*1da177e4SLinus Torvalds 1347*1da177e4SLinus Torvalds __setup("max_loop=", max_loop_setup); 1348*1da177e4SLinus Torvalds #endif 1349