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>
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 int loop_set_fd(struct loop_device
*lo
, struct file
*lo_file
,
626 struct block_device
*bdev
, unsigned int arg
)
630 struct address_space
*mapping
;
631 unsigned lo_blocksize
;
636 /* This is safe, since we have a reference from open(). */
637 __module_get(THIS_MODULE
);
640 if (lo
->lo_state
!= Lo_unbound
)
648 mapping
= file
->f_mapping
;
649 inode
= mapping
->host
;
651 if (!(file
->f_mode
& FMODE_WRITE
))
652 lo_flags
|= LO_FLAGS_READ_ONLY
;
655 if (S_ISREG(inode
->i_mode
) || S_ISBLK(inode
->i_mode
)) {
656 struct address_space_operations
*aops
= mapping
->a_ops
;
658 * If we can't read - sorry. If we only can't write - well,
659 * it's going to be read-only.
661 if (!file
->f_op
->sendfile
)
664 if (!aops
->prepare_write
|| !aops
->commit_write
)
665 lo_flags
|= LO_FLAGS_READ_ONLY
;
667 lo_blocksize
= inode
->i_blksize
;
673 size
= get_loop_size(lo
, file
);
675 if ((loff_t
)(sector_t
)size
!= size
) {
680 if (!(lo_file
->f_mode
& FMODE_WRITE
))
681 lo_flags
|= LO_FLAGS_READ_ONLY
;
683 set_device_ro(bdev
, (lo_flags
& LO_FLAGS_READ_ONLY
) != 0);
685 lo
->lo_blocksize
= lo_blocksize
;
686 lo
->lo_device
= bdev
;
687 lo
->lo_flags
= lo_flags
;
688 lo
->lo_backing_file
= file
;
691 lo
->lo_sizelimit
= 0;
692 lo
->old_gfp_mask
= mapping_gfp_mask(mapping
);
693 mapping_set_gfp_mask(mapping
, lo
->old_gfp_mask
& ~(__GFP_IO
|__GFP_FS
));
695 lo
->lo_bio
= lo
->lo_biotail
= NULL
;
698 * set queue make_request_fn, and add limits based on lower level
701 blk_queue_make_request(lo
->lo_queue
, loop_make_request
);
702 lo
->lo_queue
->queuedata
= lo
;
703 lo
->lo_queue
->unplug_fn
= loop_unplug
;
705 set_capacity(disks
[lo
->lo_number
], size
);
706 bd_set_size(bdev
, size
<< 9);
708 set_blocksize(bdev
, lo_blocksize
);
710 kernel_thread(loop_thread
, lo
, CLONE_KERNEL
);
717 /* This is safe: open() is still holding a reference. */
718 module_put(THIS_MODULE
);
723 loop_release_xfer(struct loop_device
*lo
)
726 struct loop_func_table
*xfer
= lo
->lo_encryption
;
730 err
= xfer
->release(lo
);
732 lo
->lo_encryption
= NULL
;
733 module_put(xfer
->owner
);
739 loop_init_xfer(struct loop_device
*lo
, struct loop_func_table
*xfer
,
740 const struct loop_info64
*i
)
745 struct module
*owner
= xfer
->owner
;
747 if (!try_module_get(owner
))
750 err
= xfer
->init(lo
, i
);
754 lo
->lo_encryption
= xfer
;
759 static int loop_clr_fd(struct loop_device
*lo
, struct block_device
*bdev
)
761 struct file
*filp
= lo
->lo_backing_file
;
762 int gfp
= lo
->old_gfp_mask
;
764 if (lo
->lo_state
!= Lo_bound
)
767 if (lo
->lo_refcnt
> 1) /* we needed one fd for the ioctl */
773 spin_lock_irq(&lo
->lo_lock
);
774 lo
->lo_state
= Lo_rundown
;
775 if (atomic_dec_and_test(&lo
->lo_pending
))
776 up(&lo
->lo_bh_mutex
);
777 spin_unlock_irq(&lo
->lo_lock
);
781 lo
->lo_backing_file
= NULL
;
783 loop_release_xfer(lo
);
786 lo
->lo_device
= NULL
;
787 lo
->lo_encryption
= NULL
;
789 lo
->lo_sizelimit
= 0;
790 lo
->lo_encrypt_key_size
= 0;
792 memset(lo
->lo_encrypt_key
, 0, LO_KEY_SIZE
);
793 memset(lo
->lo_crypt_name
, 0, LO_NAME_SIZE
);
794 memset(lo
->lo_file_name
, 0, LO_NAME_SIZE
);
795 invalidate_bdev(bdev
, 0);
796 set_capacity(disks
[lo
->lo_number
], 0);
797 bd_set_size(bdev
, 0);
798 mapping_set_gfp_mask(filp
->f_mapping
, gfp
);
799 lo
->lo_state
= Lo_unbound
;
801 /* This is safe: open() is still holding a reference. */
802 module_put(THIS_MODULE
);
807 loop_set_status(struct loop_device
*lo
, const struct loop_info64
*info
)
810 struct loop_func_table
*xfer
;
812 if (lo
->lo_encrypt_key_size
&& lo
->lo_key_owner
!= current
->uid
&&
813 !capable(CAP_SYS_ADMIN
))
815 if (lo
->lo_state
!= Lo_bound
)
817 if ((unsigned int) info
->lo_encrypt_key_size
> LO_KEY_SIZE
)
820 err
= loop_release_xfer(lo
);
824 if (info
->lo_encrypt_type
) {
825 unsigned int type
= info
->lo_encrypt_type
;
827 if (type
>= MAX_LO_CRYPT
)
829 xfer
= xfer_funcs
[type
];
835 err
= loop_init_xfer(lo
, xfer
, info
);
839 if (lo
->lo_offset
!= info
->lo_offset
||
840 lo
->lo_sizelimit
!= info
->lo_sizelimit
) {
841 lo
->lo_offset
= info
->lo_offset
;
842 lo
->lo_sizelimit
= info
->lo_sizelimit
;
843 if (figure_loop_size(lo
))
847 memcpy(lo
->lo_file_name
, info
->lo_file_name
, LO_NAME_SIZE
);
848 memcpy(lo
->lo_crypt_name
, info
->lo_crypt_name
, LO_NAME_SIZE
);
849 lo
->lo_file_name
[LO_NAME_SIZE
-1] = 0;
850 lo
->lo_crypt_name
[LO_NAME_SIZE
-1] = 0;
854 lo
->transfer
= xfer
->transfer
;
855 lo
->ioctl
= xfer
->ioctl
;
857 lo
->lo_encrypt_key_size
= info
->lo_encrypt_key_size
;
858 lo
->lo_init
[0] = info
->lo_init
[0];
859 lo
->lo_init
[1] = info
->lo_init
[1];
860 if (info
->lo_encrypt_key_size
) {
861 memcpy(lo
->lo_encrypt_key
, info
->lo_encrypt_key
,
862 info
->lo_encrypt_key_size
);
863 lo
->lo_key_owner
= current
->uid
;
870 loop_get_status(struct loop_device
*lo
, struct loop_info64
*info
)
872 struct file
*file
= lo
->lo_backing_file
;
876 if (lo
->lo_state
!= Lo_bound
)
878 error
= vfs_getattr(file
->f_vfsmnt
, file
->f_dentry
, &stat
);
881 memset(info
, 0, sizeof(*info
));
882 info
->lo_number
= lo
->lo_number
;
883 info
->lo_device
= huge_encode_dev(stat
.dev
);
884 info
->lo_inode
= stat
.ino
;
885 info
->lo_rdevice
= huge_encode_dev(lo
->lo_device
? stat
.rdev
: stat
.dev
);
886 info
->lo_offset
= lo
->lo_offset
;
887 info
->lo_sizelimit
= lo
->lo_sizelimit
;
888 info
->lo_flags
= lo
->lo_flags
;
889 memcpy(info
->lo_file_name
, lo
->lo_file_name
, LO_NAME_SIZE
);
890 memcpy(info
->lo_crypt_name
, lo
->lo_crypt_name
, LO_NAME_SIZE
);
891 info
->lo_encrypt_type
=
892 lo
->lo_encryption
? lo
->lo_encryption
->number
: 0;
893 if (lo
->lo_encrypt_key_size
&& capable(CAP_SYS_ADMIN
)) {
894 info
->lo_encrypt_key_size
= lo
->lo_encrypt_key_size
;
895 memcpy(info
->lo_encrypt_key
, lo
->lo_encrypt_key
,
896 lo
->lo_encrypt_key_size
);
902 loop_info64_from_old(const struct loop_info
*info
, struct loop_info64
*info64
)
904 memset(info64
, 0, sizeof(*info64
));
905 info64
->lo_number
= info
->lo_number
;
906 info64
->lo_device
= info
->lo_device
;
907 info64
->lo_inode
= info
->lo_inode
;
908 info64
->lo_rdevice
= info
->lo_rdevice
;
909 info64
->lo_offset
= info
->lo_offset
;
910 info64
->lo_sizelimit
= 0;
911 info64
->lo_encrypt_type
= info
->lo_encrypt_type
;
912 info64
->lo_encrypt_key_size
= info
->lo_encrypt_key_size
;
913 info64
->lo_flags
= info
->lo_flags
;
914 info64
->lo_init
[0] = info
->lo_init
[0];
915 info64
->lo_init
[1] = info
->lo_init
[1];
916 if (info
->lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
917 memcpy(info64
->lo_crypt_name
, info
->lo_name
, LO_NAME_SIZE
);
919 memcpy(info64
->lo_file_name
, info
->lo_name
, LO_NAME_SIZE
);
920 memcpy(info64
->lo_encrypt_key
, info
->lo_encrypt_key
, LO_KEY_SIZE
);
924 loop_info64_to_old(const struct loop_info64
*info64
, struct loop_info
*info
)
926 memset(info
, 0, sizeof(*info
));
927 info
->lo_number
= info64
->lo_number
;
928 info
->lo_device
= info64
->lo_device
;
929 info
->lo_inode
= info64
->lo_inode
;
930 info
->lo_rdevice
= info64
->lo_rdevice
;
931 info
->lo_offset
= info64
->lo_offset
;
932 info
->lo_encrypt_type
= info64
->lo_encrypt_type
;
933 info
->lo_encrypt_key_size
= info64
->lo_encrypt_key_size
;
934 info
->lo_flags
= info64
->lo_flags
;
935 info
->lo_init
[0] = info64
->lo_init
[0];
936 info
->lo_init
[1] = info64
->lo_init
[1];
937 if (info
->lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
938 memcpy(info
->lo_name
, info64
->lo_crypt_name
, LO_NAME_SIZE
);
940 memcpy(info
->lo_name
, info64
->lo_file_name
, LO_NAME_SIZE
);
941 memcpy(info
->lo_encrypt_key
, info64
->lo_encrypt_key
, LO_KEY_SIZE
);
943 /* error in case values were truncated */
944 if (info
->lo_device
!= info64
->lo_device
||
945 info
->lo_rdevice
!= info64
->lo_rdevice
||
946 info
->lo_inode
!= info64
->lo_inode
||
947 info
->lo_offset
!= info64
->lo_offset
)
954 loop_set_status_old(struct loop_device
*lo
, const struct loop_info __user
*arg
)
956 struct loop_info info
;
957 struct loop_info64 info64
;
959 if (copy_from_user(&info
, arg
, sizeof (struct loop_info
)))
961 loop_info64_from_old(&info
, &info64
);
962 return loop_set_status(lo
, &info64
);
966 loop_set_status64(struct loop_device
*lo
, const struct loop_info64 __user
*arg
)
968 struct loop_info64 info64
;
970 if (copy_from_user(&info64
, arg
, sizeof (struct loop_info64
)))
972 return loop_set_status(lo
, &info64
);
976 loop_get_status_old(struct loop_device
*lo
, struct loop_info __user
*arg
) {
977 struct loop_info info
;
978 struct loop_info64 info64
;
984 err
= loop_get_status(lo
, &info64
);
986 err
= loop_info64_to_old(&info64
, &info
);
987 if (!err
&& copy_to_user(arg
, &info
, sizeof(info
)))
994 loop_get_status64(struct loop_device
*lo
, struct loop_info64 __user
*arg
) {
995 struct loop_info64 info64
;
1001 err
= loop_get_status(lo
, &info64
);
1002 if (!err
&& copy_to_user(arg
, &info64
, sizeof(info64
)))
1008 static int lo_ioctl(struct inode
* inode
, struct file
* file
,
1009 unsigned int cmd
, unsigned long arg
)
1011 struct loop_device
*lo
= inode
->i_bdev
->bd_disk
->private_data
;
1014 down(&lo
->lo_ctl_mutex
);
1017 err
= loop_set_fd(lo
, file
, inode
->i_bdev
, arg
);
1019 case LOOP_CHANGE_FD
:
1020 err
= loop_change_fd(lo
, file
, inode
->i_bdev
, arg
);
1023 err
= loop_clr_fd(lo
, inode
->i_bdev
);
1025 case LOOP_SET_STATUS
:
1026 err
= loop_set_status_old(lo
, (struct loop_info __user
*) arg
);
1028 case LOOP_GET_STATUS
:
1029 err
= loop_get_status_old(lo
, (struct loop_info __user
*) arg
);
1031 case LOOP_SET_STATUS64
:
1032 err
= loop_set_status64(lo
, (struct loop_info64 __user
*) arg
);
1034 case LOOP_GET_STATUS64
:
1035 err
= loop_get_status64(lo
, (struct loop_info64 __user
*) arg
);
1038 err
= lo
->ioctl
? lo
->ioctl(lo
, cmd
, arg
) : -EINVAL
;
1040 up(&lo
->lo_ctl_mutex
);
1044 static int lo_open(struct inode
*inode
, struct file
*file
)
1046 struct loop_device
*lo
= inode
->i_bdev
->bd_disk
->private_data
;
1048 down(&lo
->lo_ctl_mutex
);
1050 up(&lo
->lo_ctl_mutex
);
1055 static int lo_release(struct inode
*inode
, struct file
*file
)
1057 struct loop_device
*lo
= inode
->i_bdev
->bd_disk
->private_data
;
1059 down(&lo
->lo_ctl_mutex
);
1061 up(&lo
->lo_ctl_mutex
);
1066 static struct block_device_operations lo_fops
= {
1067 .owner
= THIS_MODULE
,
1069 .release
= lo_release
,
1074 * And now the modules code and kernel interface.
1076 MODULE_PARM(max_loop
, "i");
1077 MODULE_PARM_DESC(max_loop
, "Maximum number of loop devices (1-256)");
1078 MODULE_LICENSE("GPL");
1079 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR
);
1081 int loop_register_transfer(struct loop_func_table
*funcs
)
1083 unsigned int n
= funcs
->number
;
1085 if (n
>= MAX_LO_CRYPT
|| xfer_funcs
[n
])
1087 xfer_funcs
[n
] = funcs
;
1091 int loop_unregister_transfer(int number
)
1093 unsigned int n
= number
;
1094 struct loop_device
*lo
;
1095 struct loop_func_table
*xfer
;
1097 if (n
== 0 || n
>= MAX_LO_CRYPT
|| (xfer
= xfer_funcs
[n
]) == NULL
)
1100 xfer_funcs
[n
] = NULL
;
1102 for (lo
= &loop_dev
[0]; lo
< &loop_dev
[max_loop
]; lo
++) {
1103 down(&lo
->lo_ctl_mutex
);
1105 if (lo
->lo_encryption
== xfer
)
1106 loop_release_xfer(lo
);
1108 up(&lo
->lo_ctl_mutex
);
1114 EXPORT_SYMBOL(loop_register_transfer
);
1115 EXPORT_SYMBOL(loop_unregister_transfer
);
1117 int __init
loop_init(void)
1121 if (max_loop
< 1 || max_loop
> 256) {
1122 printk(KERN_WARNING
"loop: invalid max_loop (must be between"
1123 " 1 and 256), using default (8)\n");
1127 if (register_blkdev(LOOP_MAJOR
, "loop"))
1130 loop_dev
= kmalloc(max_loop
* sizeof(struct loop_device
), GFP_KERNEL
);
1133 memset(loop_dev
, 0, max_loop
* sizeof(struct loop_device
));
1135 disks
= kmalloc(max_loop
* sizeof(struct gendisk
*), GFP_KERNEL
);
1139 for (i
= 0; i
< max_loop
; i
++) {
1140 disks
[i
] = alloc_disk(1);
1145 devfs_mk_dir("loop");
1147 for (i
= 0; i
< max_loop
; i
++) {
1148 struct loop_device
*lo
= &loop_dev
[i
];
1149 struct gendisk
*disk
= disks
[i
];
1151 memset(lo
, 0, sizeof(*lo
));
1152 lo
->lo_queue
= blk_alloc_queue(GFP_KERNEL
);
1155 init_MUTEX(&lo
->lo_ctl_mutex
);
1156 init_MUTEX_LOCKED(&lo
->lo_sem
);
1157 init_MUTEX_LOCKED(&lo
->lo_bh_mutex
);
1159 spin_lock_init(&lo
->lo_lock
);
1160 disk
->major
= LOOP_MAJOR
;
1161 disk
->first_minor
= i
;
1162 disk
->fops
= &lo_fops
;
1163 sprintf(disk
->disk_name
, "loop%d", i
);
1164 sprintf(disk
->devfs_name
, "loop/%d", i
);
1165 disk
->private_data
= lo
;
1166 disk
->queue
= lo
->lo_queue
;
1169 /* We cannot fail after we call this, so another loop!*/
1170 for (i
= 0; i
< max_loop
; i
++)
1172 printk(KERN_INFO
"loop: loaded (max %d devices)\n", max_loop
);
1177 blk_put_queue(loop_dev
[i
].lo_queue
);
1178 devfs_remove("loop");
1187 unregister_blkdev(LOOP_MAJOR
, "loop");
1188 printk(KERN_ERR
"loop: ran out of memory\n");
1192 void loop_exit(void)
1196 for (i
= 0; i
< max_loop
; i
++) {
1197 del_gendisk(disks
[i
]);
1198 blk_put_queue(loop_dev
[i
].lo_queue
);
1201 devfs_remove("loop");
1202 if (unregister_blkdev(LOOP_MAJOR
, "loop"))
1203 printk(KERN_WARNING
"loop: cannot unregister blkdev\n");
1209 module_init(loop_init
);
1210 module_exit(loop_exit
);
1213 static int __init
max_loop_setup(char *str
)
1215 max_loop
= simple_strtol(str
, NULL
, 0);
1219 __setup("max_loop=", max_loop_setup
);