2 * linux/drivers/block/loop.c
4 * Written by Theodore Ts'o, 3/29/93
6 * Copyright 1993 by Theodore Ts'o. Redistribution of this file is
7 * permitted under the GNU General Public License.
9 * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
10 * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
12 * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
13 * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
15 * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
17 * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
19 * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
21 * Loadable modules and other fixes by AK, 1998
23 * Make real block number available to downstream transfer functions, enables
24 * CBC (and relatives) mode encryption requiring unique IVs per data block.
25 * Reed H. Petty, rhp@draper.net
27 * Maximum number of loop devices now dynamic via max_loop module parameter.
28 * Russell Kroll <rkroll@exploits.org> 19990701
30 * Maximum number of loop devices when compiled-in now selectable by passing
31 * max_loop=<1-255> to the kernel on boot.
32 * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999
34 * Completely rewrite request handling to be make_request_fn style and
35 * non blocking, pushing work to a helper thread. Lots of fixes from
37 * Jens Axboe <axboe@suse.de>, Nov 2000
39 * Support up to 256 loop devices
40 * Heinz Mauelshagen <mge@sistina.com>, Feb 2002
43 * - Advisory locking is ignored here.
44 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
48 #include <linux/config.h>
49 #include <linux/module.h>
50 #include <linux/moduleparam.h>
51 #include <linux/sched.h>
53 #include <linux/file.h>
54 #include <linux/stat.h>
55 #include <linux/errno.h>
56 #include <linux/major.h>
57 #include <linux/wait.h>
58 #include <linux/blkdev.h>
59 #include <linux/blkpg.h>
60 #include <linux/init.h>
61 #include <linux/devfs_fs_kernel.h>
62 #include <linux/smp_lock.h>
63 #include <linux/swap.h>
64 #include <linux/slab.h>
65 #include <linux/loop.h>
66 #include <linux/suspend.h>
67 #include <linux/writeback.h>
68 #include <linux/buffer_head.h> /* for invalidate_bdev() */
69 #include <linux/completion.h>
71 #include <asm/uaccess.h>
73 static int max_loop = 8;
74 static struct loop_device *loop_dev;
75 static struct gendisk **disks;
80 static int transfer_none(struct loop_device *lo, int cmd,
81 struct page *raw_page, unsigned raw_off,
82 struct page *loop_page, unsigned loop_off,
83 int size, sector_t real_block)
85 char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off;
86 char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off;
89 memcpy(loop_buf, raw_buf, size);
91 memcpy(raw_buf, loop_buf, size);
93 kunmap_atomic(raw_buf, KM_USER0);
94 kunmap_atomic(loop_buf, KM_USER1);
99 static int transfer_xor(struct loop_device *lo, int cmd,
100 struct page *raw_page, unsigned raw_off,
101 struct page *loop_page, unsigned loop_off,
102 int size, sector_t real_block)
104 char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off;
105 char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off;
106 char *in, *out, *key;
117 key = lo->lo_encrypt_key;
118 keysize = lo->lo_encrypt_key_size;
119 for (i = 0; i < size; i++)
120 *out++ = *in++ ^ key[(i & 511) % keysize];
122 kunmap_atomic(raw_buf, KM_USER0);
123 kunmap_atomic(loop_buf, KM_USER1);
128 static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
130 if (info->lo_encrypt_key_size <= 0)
135 static struct loop_func_table none_funcs = {
136 .number = LO_CRYPT_NONE,
137 .transfer = transfer_none,
140 static struct loop_func_table xor_funcs = {
141 .number = LO_CRYPT_XOR,
142 .transfer = transfer_xor,
146 /* xfer_funcs[0] is special - its release function is never called */
147 static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
152 static loff_t get_loop_size(struct loop_device *lo, struct file *file)
154 loff_t size, offset, loopsize;
156 /* Compute loopsize in bytes */
157 size = i_size_read(file->f_mapping->host);
158 offset = lo->lo_offset;
159 loopsize = size - offset;
160 if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
161 loopsize = lo->lo_sizelimit;
164 * Unfortunately, if we want to do I/O on the device,
165 * the number of 512-byte sectors has to fit into a sector_t.
167 return loopsize >> 9;
171 figure_loop_size(struct loop_device *lo)
173 loff_t size = get_loop_size(lo, lo->lo_backing_file);
174 sector_t x = (sector_t)size;
176 if ((loff_t)x != size)
179 set_capacity(disks[lo->lo_number], x);
184 lo_do_transfer(struct loop_device *lo, int cmd,
185 struct page *rpage, unsigned roffs,
186 struct page *lpage, unsigned loffs,
187 int size, sector_t rblock)
192 return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
196 do_lo_send(struct loop_device *lo, struct bio_vec *bvec, int bsize, loff_t pos)
198 struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
199 struct address_space *mapping = file->f_mapping;
200 struct address_space_operations *aops = mapping->a_ops;
203 unsigned size, offset, bv_offs;
207 down(&mapping->host->i_sem);
208 index = pos >> PAGE_CACHE_SHIFT;
209 offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1);
210 bv_offs = bvec->bv_offset;
216 IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
218 size = PAGE_CACHE_SIZE - offset;
222 page = grab_cache_page(mapping, index);
225 if (aops->prepare_write(file, page, offset, offset+size))
227 transfer_result = lo_do_transfer(lo, WRITE, page, offset,
228 bvec->bv_page, bv_offs,
230 if (transfer_result) {
234 * The transfer failed, but we still write the data to
235 * keep prepare/commit calls balanced.
237 printk(KERN_ERR "loop: transfer error block %llu\n",
238 (unsigned long long)index);
239 kaddr = kmap_atomic(page, KM_USER0);
240 memset(kaddr + offset, 0, size);
241 kunmap_atomic(kaddr, KM_USER0);
243 flush_dcache_page(page);
244 if (aops->commit_write(file, page, offset, offset+size))
254 page_cache_release(page);
256 up(&mapping->host->i_sem);
262 page_cache_release(page);
264 up(&mapping->host->i_sem);
270 lo_send(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
272 struct bio_vec *bvec;
275 bio_for_each_segment(bvec, bio, i) {
276 ret = do_lo_send(lo, bvec, bsize, pos);
284 struct lo_read_data {
285 struct loop_device *lo;
292 lo_read_actor(read_descriptor_t *desc, struct page *page,
293 unsigned long offset, unsigned long size)
295 unsigned long count = desc->count;
296 struct lo_read_data *p = desc->arg.data;
297 struct loop_device *lo = p->lo;
300 IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
305 if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) {
307 printk(KERN_ERR "loop: transfer error block %ld\n",
309 desc->error = -EINVAL;
312 flush_dcache_page(p->page);
314 desc->count = count - size;
315 desc->written += size;
321 do_lo_receive(struct loop_device *lo,
322 struct bio_vec *bvec, int bsize, loff_t pos)
324 struct lo_read_data cookie;
329 cookie.page = bvec->bv_page;
330 cookie.offset = bvec->bv_offset;
331 cookie.bsize = bsize;
332 file = lo->lo_backing_file;
333 retval = file->f_op->sendfile(file, &pos, bvec->bv_len,
334 lo_read_actor, &cookie);
335 return (retval < 0)? retval: 0;
339 lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
341 struct bio_vec *bvec;
344 bio_for_each_segment(bvec, bio, i) {
345 ret = do_lo_receive(lo, bvec, bsize, pos);
353 static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
358 pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset;
359 if (bio_rw(bio) == WRITE)
360 ret = lo_send(lo, bio, lo->lo_blocksize, pos);
362 ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
367 * Add bio to back of pending list
369 static void loop_add_bio(struct loop_device *lo, struct bio *bio)
373 spin_lock_irqsave(&lo->lo_lock, flags);
374 if (lo->lo_biotail) {
375 lo->lo_biotail->bi_next = bio;
376 lo->lo_biotail = bio;
378 lo->lo_bio = lo->lo_biotail = bio;
379 spin_unlock_irqrestore(&lo->lo_lock, flags);
381 up(&lo->lo_bh_mutex);
385 * Grab first pending buffer
387 static struct bio *loop_get_bio(struct loop_device *lo)
391 spin_lock_irq(&lo->lo_lock);
392 if ((bio = lo->lo_bio)) {
393 if (bio == lo->lo_biotail)
394 lo->lo_biotail = NULL;
395 lo->lo_bio = bio->bi_next;
398 spin_unlock_irq(&lo->lo_lock);
403 static int loop_make_request(request_queue_t *q, struct bio *old_bio)
405 struct loop_device *lo = q->queuedata;
406 int rw = bio_rw(old_bio);
411 spin_lock_irq(&lo->lo_lock);
412 if (lo->lo_state != Lo_bound)
414 atomic_inc(&lo->lo_pending);
415 spin_unlock_irq(&lo->lo_lock);
418 if (lo->lo_flags & LO_FLAGS_READ_ONLY)
420 } else if (rw == READA) {
422 } else if (rw != READ) {
423 printk(KERN_ERR "loop: unknown command (%x)\n", rw);
426 loop_add_bio(lo, old_bio);
429 if (atomic_dec_and_test(&lo->lo_pending))
430 up(&lo->lo_bh_mutex);
432 bio_io_error(old_bio, old_bio->bi_size);
435 spin_unlock_irq(&lo->lo_lock);
440 * kick off io on the underlying address space
442 static void loop_unplug(request_queue_t *q)
444 struct loop_device *lo = q->queuedata;
446 clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags);
447 blk_run_address_space(lo->lo_backing_file->f_mapping);
450 struct switch_request {
452 struct completion wait;
455 static void do_loop_switch(struct loop_device *, struct switch_request *);
457 static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio)
461 if (unlikely(!bio->bi_bdev)) {
462 do_loop_switch(lo, bio->bi_private);
465 ret = do_bio_filebacked(lo, bio);
466 bio_endio(bio, bio->bi_size, ret);
471 * worker thread that handles reads/writes to file backed loop devices,
472 * to avoid blocking in our make_request_fn. it also does loop decrypting
473 * on reads for block backed loop, as that is too heavy to do from
474 * b_end_io context where irqs may be disabled.
476 static int loop_thread(void *data)
478 struct loop_device *lo = data;
481 daemonize("loop%d", lo->lo_number);
484 * loop can be used in an encrypted device,
485 * hence, it mustn't be stopped at all
486 * because it could be indirectly used during suspension
488 current->flags |= PF_NOFREEZE;
490 set_user_nice(current, -20);
492 lo->lo_state = Lo_bound;
493 atomic_inc(&lo->lo_pending);
496 * up sem, we are running
501 down_interruptible(&lo->lo_bh_mutex);
503 * could be upped because of tear-down, not because of
506 if (!atomic_read(&lo->lo_pending))
509 bio = loop_get_bio(lo);
511 printk("loop: missing bio\n");
514 loop_handle_bio(lo, bio);
517 * upped both for pending work and tear-down, lo_pending
520 if (atomic_dec_and_test(&lo->lo_pending))
529 * loop_switch performs the hard work of switching a backing store.
530 * First it needs to flush existing IO, it does this by sending a magic
531 * BIO down the pipe. The completion of this BIO does the actual switch.
533 static int loop_switch(struct loop_device *lo, struct file *file)
535 struct switch_request w;
536 struct bio *bio = bio_alloc(GFP_KERNEL, 1);
539 init_completion(&w.wait);
541 bio->bi_private = &w;
543 loop_make_request(lo->lo_queue, bio);
544 wait_for_completion(&w.wait);
549 * Do the actual switch; called from the BIO completion routine
551 static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
553 struct file *file = p->file;
554 struct file *old_file = lo->lo_backing_file;
555 struct address_space *mapping = file->f_mapping;
557 mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
558 lo->lo_backing_file = file;
559 lo->lo_blocksize = mapping->host->i_blksize;
560 lo->old_gfp_mask = mapping_gfp_mask(mapping);
561 mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
567 * loop_change_fd switched the backing store of a loopback device to
568 * a new file. This is useful for operating system installers to free up
569 * the original file and in High Availability environments to switch to
570 * an alternative location for the content in case of server meltdown.
571 * This can only work if the loop device is used read-only, and if the
572 * new backing store is the same size and type as the old backing store.
574 static int loop_change_fd(struct loop_device *lo, struct file *lo_file,
575 struct block_device *bdev, unsigned int arg)
577 struct file *file, *old_file;
582 if (lo->lo_state != Lo_bound)
585 /* the loop device has to be read-only */
587 if (lo->lo_flags != LO_FLAGS_READ_ONLY)
595 inode = file->f_mapping->host;
596 old_file = lo->lo_backing_file;
600 if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
603 /* new backing store needs to support loop (eg sendfile) */
604 if (!inode->i_fop->sendfile)
607 /* size of the new backing store needs to be the same */
608 if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
612 error = loop_switch(lo, file);
625 static inline int is_loop_device(struct file *file)
627 struct inode *i = file->f_mapping->host;
629 return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR;
632 static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
633 struct block_device *bdev, unsigned int arg)
635 struct file *file, *f;
637 struct address_space *mapping;
638 unsigned lo_blocksize;
643 /* This is safe, since we have a reference from open(). */
644 __module_get(THIS_MODULE);
652 if (lo->lo_state != Lo_unbound)
655 /* Avoid recursion */
657 while (is_loop_device(f)) {
658 struct loop_device *l;
660 if (f->f_mapping->host->i_rdev == lo_file->f_mapping->host->i_rdev)
663 l = f->f_mapping->host->i_bdev->bd_disk->private_data;
664 if (l->lo_state == Lo_unbound) {
668 f = l->lo_backing_file;
671 mapping = file->f_mapping;
672 inode = mapping->host;
674 if (!(file->f_mode & FMODE_WRITE))
675 lo_flags |= LO_FLAGS_READ_ONLY;
678 if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) {
679 struct address_space_operations *aops = mapping->a_ops;
681 * If we can't read - sorry. If we only can't write - well,
682 * it's going to be read-only.
684 if (!file->f_op->sendfile)
687 if (!aops->prepare_write || !aops->commit_write)
688 lo_flags |= LO_FLAGS_READ_ONLY;
690 lo_blocksize = inode->i_blksize;
696 size = get_loop_size(lo, file);
698 if ((loff_t)(sector_t)size != size) {
703 if (!(lo_file->f_mode & FMODE_WRITE))
704 lo_flags |= LO_FLAGS_READ_ONLY;
706 set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
708 lo->lo_blocksize = lo_blocksize;
709 lo->lo_device = bdev;
710 lo->lo_flags = lo_flags;
711 lo->lo_backing_file = file;
714 lo->lo_sizelimit = 0;
715 lo->old_gfp_mask = mapping_gfp_mask(mapping);
716 mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
718 lo->lo_bio = lo->lo_biotail = NULL;
721 * set queue make_request_fn, and add limits based on lower level
724 blk_queue_make_request(lo->lo_queue, loop_make_request);
725 lo->lo_queue->queuedata = lo;
726 lo->lo_queue->unplug_fn = loop_unplug;
728 set_capacity(disks[lo->lo_number], size);
729 bd_set_size(bdev, size << 9);
731 set_blocksize(bdev, lo_blocksize);
733 kernel_thread(loop_thread, lo, CLONE_KERNEL);
740 /* This is safe: open() is still holding a reference. */
741 module_put(THIS_MODULE);
746 loop_release_xfer(struct loop_device *lo)
749 struct loop_func_table *xfer = lo->lo_encryption;
753 err = xfer->release(lo);
755 lo->lo_encryption = NULL;
756 module_put(xfer->owner);
762 loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
763 const struct loop_info64 *i)
768 struct module *owner = xfer->owner;
770 if (!try_module_get(owner))
773 err = xfer->init(lo, i);
777 lo->lo_encryption = xfer;
782 static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
784 struct file *filp = lo->lo_backing_file;
785 int gfp = lo->old_gfp_mask;
787 if (lo->lo_state != Lo_bound)
790 if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */
796 spin_lock_irq(&lo->lo_lock);
797 lo->lo_state = Lo_rundown;
798 if (atomic_dec_and_test(&lo->lo_pending))
799 up(&lo->lo_bh_mutex);
800 spin_unlock_irq(&lo->lo_lock);
804 lo->lo_backing_file = NULL;
806 loop_release_xfer(lo);
809 lo->lo_device = NULL;
810 lo->lo_encryption = NULL;
812 lo->lo_sizelimit = 0;
813 lo->lo_encrypt_key_size = 0;
815 memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
816 memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
817 memset(lo->lo_file_name, 0, LO_NAME_SIZE);
818 invalidate_bdev(bdev, 0);
819 set_capacity(disks[lo->lo_number], 0);
820 bd_set_size(bdev, 0);
821 mapping_set_gfp_mask(filp->f_mapping, gfp);
822 lo->lo_state = Lo_unbound;
824 /* This is safe: open() is still holding a reference. */
825 module_put(THIS_MODULE);
830 loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
833 struct loop_func_table *xfer;
835 if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
836 !capable(CAP_SYS_ADMIN))
838 if (lo->lo_state != Lo_bound)
840 if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
843 err = loop_release_xfer(lo);
847 if (info->lo_encrypt_type) {
848 unsigned int type = info->lo_encrypt_type;
850 if (type >= MAX_LO_CRYPT)
852 xfer = xfer_funcs[type];
858 err = loop_init_xfer(lo, xfer, info);
862 if (lo->lo_offset != info->lo_offset ||
863 lo->lo_sizelimit != info->lo_sizelimit) {
864 lo->lo_offset = info->lo_offset;
865 lo->lo_sizelimit = info->lo_sizelimit;
866 if (figure_loop_size(lo))
870 memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
871 memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
872 lo->lo_file_name[LO_NAME_SIZE-1] = 0;
873 lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
877 lo->transfer = xfer->transfer;
878 lo->ioctl = xfer->ioctl;
880 lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
881 lo->lo_init[0] = info->lo_init[0];
882 lo->lo_init[1] = info->lo_init[1];
883 if (info->lo_encrypt_key_size) {
884 memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
885 info->lo_encrypt_key_size);
886 lo->lo_key_owner = current->uid;
893 loop_get_status(struct loop_device *lo, struct loop_info64 *info)
895 struct file *file = lo->lo_backing_file;
899 if (lo->lo_state != Lo_bound)
901 error = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat);
904 memset(info, 0, sizeof(*info));
905 info->lo_number = lo->lo_number;
906 info->lo_device = huge_encode_dev(stat.dev);
907 info->lo_inode = stat.ino;
908 info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev);
909 info->lo_offset = lo->lo_offset;
910 info->lo_sizelimit = lo->lo_sizelimit;
911 info->lo_flags = lo->lo_flags;
912 memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
913 memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
914 info->lo_encrypt_type =
915 lo->lo_encryption ? lo->lo_encryption->number : 0;
916 if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
917 info->lo_encrypt_key_size = lo->lo_encrypt_key_size;
918 memcpy(info->lo_encrypt_key, lo->lo_encrypt_key,
919 lo->lo_encrypt_key_size);
925 loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64)
927 memset(info64, 0, sizeof(*info64));
928 info64->lo_number = info->lo_number;
929 info64->lo_device = info->lo_device;
930 info64->lo_inode = info->lo_inode;
931 info64->lo_rdevice = info->lo_rdevice;
932 info64->lo_offset = info->lo_offset;
933 info64->lo_sizelimit = 0;
934 info64->lo_encrypt_type = info->lo_encrypt_type;
935 info64->lo_encrypt_key_size = info->lo_encrypt_key_size;
936 info64->lo_flags = info->lo_flags;
937 info64->lo_init[0] = info->lo_init[0];
938 info64->lo_init[1] = info->lo_init[1];
939 if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
940 memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
942 memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
943 memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
947 loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
949 memset(info, 0, sizeof(*info));
950 info->lo_number = info64->lo_number;
951 info->lo_device = info64->lo_device;
952 info->lo_inode = info64->lo_inode;
953 info->lo_rdevice = info64->lo_rdevice;
954 info->lo_offset = info64->lo_offset;
955 info->lo_encrypt_type = info64->lo_encrypt_type;
956 info->lo_encrypt_key_size = info64->lo_encrypt_key_size;
957 info->lo_flags = info64->lo_flags;
958 info->lo_init[0] = info64->lo_init[0];
959 info->lo_init[1] = info64->lo_init[1];
960 if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
961 memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
963 memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
964 memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
966 /* error in case values were truncated */
967 if (info->lo_device != info64->lo_device ||
968 info->lo_rdevice != info64->lo_rdevice ||
969 info->lo_inode != info64->lo_inode ||
970 info->lo_offset != info64->lo_offset)
977 loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg)
979 struct loop_info info;
980 struct loop_info64 info64;
982 if (copy_from_user(&info, arg, sizeof (struct loop_info)))
984 loop_info64_from_old(&info, &info64);
985 return loop_set_status(lo, &info64);
989 loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg)
991 struct loop_info64 info64;
993 if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
995 return loop_set_status(lo, &info64);
999 loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) {
1000 struct loop_info info;
1001 struct loop_info64 info64;
1007 err = loop_get_status(lo, &info64);
1009 err = loop_info64_to_old(&info64, &info);
1010 if (!err && copy_to_user(arg, &info, sizeof(info)))
1017 loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
1018 struct loop_info64 info64;
1024 err = loop_get_status(lo, &info64);
1025 if (!err && copy_to_user(arg, &info64, sizeof(info64)))
1031 static int lo_ioctl(struct inode * inode, struct file * file,
1032 unsigned int cmd, unsigned long arg)
1034 struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
1037 down(&lo->lo_ctl_mutex);
1040 err = loop_set_fd(lo, file, inode->i_bdev, arg);
1042 case LOOP_CHANGE_FD:
1043 err = loop_change_fd(lo, file, inode->i_bdev, arg);
1046 err = loop_clr_fd(lo, inode->i_bdev);
1048 case LOOP_SET_STATUS:
1049 err = loop_set_status_old(lo, (struct loop_info __user *) arg);
1051 case LOOP_GET_STATUS:
1052 err = loop_get_status_old(lo, (struct loop_info __user *) arg);
1054 case LOOP_SET_STATUS64:
1055 err = loop_set_status64(lo, (struct loop_info64 __user *) arg);
1057 case LOOP_GET_STATUS64:
1058 err = loop_get_status64(lo, (struct loop_info64 __user *) arg);
1061 err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
1063 up(&lo->lo_ctl_mutex);
1067 static int lo_open(struct inode *inode, struct file *file)
1069 struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
1071 down(&lo->lo_ctl_mutex);
1073 up(&lo->lo_ctl_mutex);
1078 static int lo_release(struct inode *inode, struct file *file)
1080 struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
1082 down(&lo->lo_ctl_mutex);
1084 up(&lo->lo_ctl_mutex);
1089 static struct block_device_operations lo_fops = {
1090 .owner = THIS_MODULE,
1092 .release = lo_release,
1097 * And now the modules code and kernel interface.
1099 module_param(max_loop, int, 0);
1100 MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)");
1101 MODULE_LICENSE("GPL");
1102 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
1104 int loop_register_transfer(struct loop_func_table *funcs)
1106 unsigned int n = funcs->number;
1108 if (n >= MAX_LO_CRYPT || xfer_funcs[n])
1110 xfer_funcs[n] = funcs;
1114 int loop_unregister_transfer(int number)
1116 unsigned int n = number;
1117 struct loop_device *lo;
1118 struct loop_func_table *xfer;
1120 if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
1123 xfer_funcs[n] = NULL;
1125 for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
1126 down(&lo->lo_ctl_mutex);
1128 if (lo->lo_encryption == xfer)
1129 loop_release_xfer(lo);
1131 up(&lo->lo_ctl_mutex);
1137 EXPORT_SYMBOL(loop_register_transfer);
1138 EXPORT_SYMBOL(loop_unregister_transfer);
1140 int __init loop_init(void)
1144 if (max_loop < 1 || max_loop > 256) {
1145 printk(KERN_WARNING "loop: invalid max_loop (must be between"
1146 " 1 and 256), using default (8)\n");
1150 if (register_blkdev(LOOP_MAJOR, "loop"))
1153 loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL);
1156 memset(loop_dev, 0, max_loop * sizeof(struct loop_device));
1158 disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL);
1162 for (i = 0; i < max_loop; i++) {
1163 disks[i] = alloc_disk(1);
1168 devfs_mk_dir("loop");
1170 for (i = 0; i < max_loop; i++) {
1171 struct loop_device *lo = &loop_dev[i];
1172 struct gendisk *disk = disks[i];
1174 memset(lo, 0, sizeof(*lo));
1175 lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
1178 init_MUTEX(&lo->lo_ctl_mutex);
1179 init_MUTEX_LOCKED(&lo->lo_sem);
1180 init_MUTEX_LOCKED(&lo->lo_bh_mutex);
1182 spin_lock_init(&lo->lo_lock);
1183 disk->major = LOOP_MAJOR;
1184 disk->first_minor = i;
1185 disk->fops = &lo_fops;
1186 sprintf(disk->disk_name, "loop%d", i);
1187 sprintf(disk->devfs_name, "loop/%d", i);
1188 disk->private_data = lo;
1189 disk->queue = lo->lo_queue;
1192 /* We cannot fail after we call this, so another loop!*/
1193 for (i = 0; i < max_loop; i++)
1195 printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop);
1200 blk_put_queue(loop_dev[i].lo_queue);
1201 devfs_remove("loop");
1210 unregister_blkdev(LOOP_MAJOR, "loop");
1211 printk(KERN_ERR "loop: ran out of memory\n");
1215 void loop_exit(void)
1219 for (i = 0; i < max_loop; i++) {
1220 del_gendisk(disks[i]);
1221 blk_put_queue(loop_dev[i].lo_queue);
1224 devfs_remove("loop");
1225 if (unregister_blkdev(LOOP_MAJOR, "loop"))
1226 printk(KERN_WARNING "loop: cannot unregister blkdev\n");
1232 module_init(loop_init);
1233 module_exit(loop_exit);
1236 static int __init max_loop_setup(char *str)
1238 max_loop = simple_strtol(str, NULL, 0);
1242 __setup("max_loop=", max_loop_setup);