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
42 * Support for falling back on the write file operation when the address space
43 * operations prepare_write and/or commit_write are not available on the
45 * Anton Altaparmakov, 16 Feb 2005
48 * - Advisory locking is ignored here.
49 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
53 #include <linux/module.h>
54 #include <linux/moduleparam.h>
55 #include <linux/sched.h>
57 #include <linux/file.h>
58 #include <linux/stat.h>
59 #include <linux/errno.h>
60 #include <linux/major.h>
61 #include <linux/wait.h>
62 #include <linux/blkdev.h>
63 #include <linux/blkpg.h>
64 #include <linux/init.h>
65 #include <linux/smp_lock.h>
66 #include <linux/swap.h>
67 #include <linux/slab.h>
68 #include <linux/loop.h>
69 #include <linux/suspend.h>
70 #include <linux/writeback.h>
71 #include <linux/buffer_head.h> /* for invalidate_bdev() */
72 #include <linux/completion.h>
73 #include <linux/highmem.h>
74 #include <linux/gfp.h>
76 #include <asm/uaccess.h>
78 static int max_loop
= 8;
79 static struct loop_device
*loop_dev
;
80 static struct gendisk
**disks
;
85 static int transfer_none(struct loop_device
*lo
, int cmd
,
86 struct page
*raw_page
, unsigned raw_off
,
87 struct page
*loop_page
, unsigned loop_off
,
88 int size
, sector_t real_block
)
90 char *raw_buf
= kmap_atomic(raw_page
, KM_USER0
) + raw_off
;
91 char *loop_buf
= kmap_atomic(loop_page
, KM_USER1
) + loop_off
;
94 memcpy(loop_buf
, raw_buf
, size
);
96 memcpy(raw_buf
, loop_buf
, size
);
98 kunmap_atomic(raw_buf
, KM_USER0
);
99 kunmap_atomic(loop_buf
, KM_USER1
);
104 static int transfer_xor(struct loop_device
*lo
, int cmd
,
105 struct page
*raw_page
, unsigned raw_off
,
106 struct page
*loop_page
, unsigned loop_off
,
107 int size
, sector_t real_block
)
109 char *raw_buf
= kmap_atomic(raw_page
, KM_USER0
) + raw_off
;
110 char *loop_buf
= kmap_atomic(loop_page
, KM_USER1
) + loop_off
;
111 char *in
, *out
, *key
;
122 key
= lo
->lo_encrypt_key
;
123 keysize
= lo
->lo_encrypt_key_size
;
124 for (i
= 0; i
< size
; i
++)
125 *out
++ = *in
++ ^ key
[(i
& 511) % keysize
];
127 kunmap_atomic(raw_buf
, KM_USER0
);
128 kunmap_atomic(loop_buf
, KM_USER1
);
133 static int xor_init(struct loop_device
*lo
, const struct loop_info64
*info
)
135 if (unlikely(info
->lo_encrypt_key_size
<= 0))
140 static struct loop_func_table none_funcs
= {
141 .number
= LO_CRYPT_NONE
,
142 .transfer
= transfer_none
,
145 static struct loop_func_table xor_funcs
= {
146 .number
= LO_CRYPT_XOR
,
147 .transfer
= transfer_xor
,
151 /* xfer_funcs[0] is special - its release function is never called */
152 static struct loop_func_table
*xfer_funcs
[MAX_LO_CRYPT
] = {
157 static loff_t
get_loop_size(struct loop_device
*lo
, struct file
*file
)
159 loff_t size
, offset
, loopsize
;
161 /* Compute loopsize in bytes */
162 size
= i_size_read(file
->f_mapping
->host
);
163 offset
= lo
->lo_offset
;
164 loopsize
= size
- offset
;
165 if (lo
->lo_sizelimit
> 0 && lo
->lo_sizelimit
< loopsize
)
166 loopsize
= lo
->lo_sizelimit
;
169 * Unfortunately, if we want to do I/O on the device,
170 * the number of 512-byte sectors has to fit into a sector_t.
172 return loopsize
>> 9;
176 figure_loop_size(struct loop_device
*lo
)
178 loff_t size
= get_loop_size(lo
, lo
->lo_backing_file
);
179 sector_t x
= (sector_t
)size
;
181 if (unlikely((loff_t
)x
!= size
))
184 set_capacity(disks
[lo
->lo_number
], x
);
189 lo_do_transfer(struct loop_device
*lo
, int cmd
,
190 struct page
*rpage
, unsigned roffs
,
191 struct page
*lpage
, unsigned loffs
,
192 int size
, sector_t rblock
)
194 if (unlikely(!lo
->transfer
))
197 return lo
->transfer(lo
, cmd
, rpage
, roffs
, lpage
, loffs
, size
, rblock
);
201 * do_lo_send_aops - helper for writing data to a loop device
203 * This is the fast version for backing filesystems which implement the address
204 * space operations prepare_write and commit_write.
206 static int do_lo_send_aops(struct loop_device
*lo
, struct bio_vec
*bvec
,
207 int bsize
, loff_t pos
, struct page
*page
)
209 struct file
*file
= lo
->lo_backing_file
; /* kudos to NFsckingS */
210 struct address_space
*mapping
= file
->f_mapping
;
211 const struct address_space_operations
*aops
= mapping
->a_ops
;
213 unsigned offset
, bv_offs
;
216 mutex_lock(&mapping
->host
->i_mutex
);
217 index
= pos
>> PAGE_CACHE_SHIFT
;
218 offset
= pos
& ((pgoff_t
)PAGE_CACHE_SIZE
- 1);
219 bv_offs
= bvec
->bv_offset
;
226 IV
= ((sector_t
)index
<< (PAGE_CACHE_SHIFT
- 9))+(offset
>> 9);
227 size
= PAGE_CACHE_SIZE
- offset
;
230 page
= grab_cache_page(mapping
, index
);
233 ret
= aops
->prepare_write(file
, page
, offset
,
236 if (ret
== AOP_TRUNCATED_PAGE
) {
237 page_cache_release(page
);
242 transfer_result
= lo_do_transfer(lo
, WRITE
, page
, offset
,
243 bvec
->bv_page
, bv_offs
, size
, IV
);
244 if (unlikely(transfer_result
)) {
248 * The transfer failed, but we still write the data to
249 * keep prepare/commit calls balanced.
251 printk(KERN_ERR
"loop: transfer error block %llu\n",
252 (unsigned long long)index
);
253 kaddr
= kmap_atomic(page
, KM_USER0
);
254 memset(kaddr
+ offset
, 0, size
);
255 kunmap_atomic(kaddr
, KM_USER0
);
257 flush_dcache_page(page
);
258 ret
= aops
->commit_write(file
, page
, offset
,
261 if (ret
== AOP_TRUNCATED_PAGE
) {
262 page_cache_release(page
);
267 if (unlikely(transfer_result
))
275 page_cache_release(page
);
279 mutex_unlock(&mapping
->host
->i_mutex
);
283 page_cache_release(page
);
290 * __do_lo_send_write - helper for writing data to a loop device
292 * This helper just factors out common code between do_lo_send_direct_write()
293 * and do_lo_send_write().
295 static int __do_lo_send_write(struct file
*file
,
296 u8 __user
*buf
, const int len
, loff_t pos
)
299 mm_segment_t old_fs
= get_fs();
302 bw
= file
->f_op
->write(file
, buf
, len
, &pos
);
304 if (likely(bw
== len
))
306 printk(KERN_ERR
"loop: Write error at byte offset %llu, length %i.\n",
307 (unsigned long long)pos
, len
);
314 * do_lo_send_direct_write - helper for writing data to a loop device
316 * This is the fast, non-transforming version for backing filesystems which do
317 * not implement the address space operations prepare_write and commit_write.
318 * It uses the write file operation which should be present on all writeable
321 static int do_lo_send_direct_write(struct loop_device
*lo
,
322 struct bio_vec
*bvec
, int bsize
, loff_t pos
, struct page
*page
)
324 ssize_t bw
= __do_lo_send_write(lo
->lo_backing_file
,
325 (u8 __user
*)kmap(bvec
->bv_page
) + bvec
->bv_offset
,
327 kunmap(bvec
->bv_page
);
333 * do_lo_send_write - helper for writing data to a loop device
335 * This is the slow, transforming version for filesystems which do not
336 * implement the address space operations prepare_write and commit_write. It
337 * uses the write file operation which should be present on all writeable
340 * Using fops->write is slower than using aops->{prepare,commit}_write in the
341 * transforming case because we need to double buffer the data as we cannot do
342 * the transformations in place as we do not have direct access to the
343 * destination pages of the backing file.
345 static int do_lo_send_write(struct loop_device
*lo
, struct bio_vec
*bvec
,
346 int bsize
, loff_t pos
, struct page
*page
)
348 int ret
= lo_do_transfer(lo
, WRITE
, page
, 0, bvec
->bv_page
,
349 bvec
->bv_offset
, bvec
->bv_len
, pos
>> 9);
351 return __do_lo_send_write(lo
->lo_backing_file
,
352 (u8 __user
*)page_address(page
), bvec
->bv_len
,
354 printk(KERN_ERR
"loop: Transfer error at byte offset %llu, "
355 "length %i.\n", (unsigned long long)pos
, bvec
->bv_len
);
361 static int lo_send(struct loop_device
*lo
, struct bio
*bio
, int bsize
,
364 int (*do_lo_send
)(struct loop_device
*, struct bio_vec
*, int, loff_t
,
366 struct bio_vec
*bvec
;
367 struct page
*page
= NULL
;
370 do_lo_send
= do_lo_send_aops
;
371 if (!(lo
->lo_flags
& LO_FLAGS_USE_AOPS
)) {
372 do_lo_send
= do_lo_send_direct_write
;
373 if (lo
->transfer
!= transfer_none
) {
374 page
= alloc_page(GFP_NOIO
| __GFP_HIGHMEM
);
378 do_lo_send
= do_lo_send_write
;
381 bio_for_each_segment(bvec
, bio
, i
) {
382 ret
= do_lo_send(lo
, bvec
, bsize
, pos
, page
);
394 printk(KERN_ERR
"loop: Failed to allocate temporary page for write.\n");
399 struct lo_read_data
{
400 struct loop_device
*lo
;
407 lo_read_actor(read_descriptor_t
*desc
, struct page
*page
,
408 unsigned long offset
, unsigned long size
)
410 unsigned long count
= desc
->count
;
411 struct lo_read_data
*p
= desc
->arg
.data
;
412 struct loop_device
*lo
= p
->lo
;
415 IV
= ((sector_t
) page
->index
<< (PAGE_CACHE_SHIFT
- 9))+(offset
>> 9);
420 if (lo_do_transfer(lo
, READ
, page
, offset
, p
->page
, p
->offset
, size
, IV
)) {
422 printk(KERN_ERR
"loop: transfer error block %ld\n",
424 desc
->error
= -EINVAL
;
427 flush_dcache_page(p
->page
);
429 desc
->count
= count
- size
;
430 desc
->written
+= size
;
436 do_lo_receive(struct loop_device
*lo
,
437 struct bio_vec
*bvec
, int bsize
, loff_t pos
)
439 struct lo_read_data cookie
;
444 cookie
.page
= bvec
->bv_page
;
445 cookie
.offset
= bvec
->bv_offset
;
446 cookie
.bsize
= bsize
;
447 file
= lo
->lo_backing_file
;
448 retval
= file
->f_op
->sendfile(file
, &pos
, bvec
->bv_len
,
449 lo_read_actor
, &cookie
);
450 return (retval
< 0)? retval
: 0;
454 lo_receive(struct loop_device
*lo
, struct bio
*bio
, int bsize
, loff_t pos
)
456 struct bio_vec
*bvec
;
459 bio_for_each_segment(bvec
, bio
, i
) {
460 ret
= do_lo_receive(lo
, bvec
, bsize
, pos
);
468 static int do_bio_filebacked(struct loop_device
*lo
, struct bio
*bio
)
473 pos
= ((loff_t
) bio
->bi_sector
<< 9) + lo
->lo_offset
;
474 if (bio_rw(bio
) == WRITE
)
475 ret
= lo_send(lo
, bio
, lo
->lo_blocksize
, pos
);
477 ret
= lo_receive(lo
, bio
, lo
->lo_blocksize
, pos
);
482 * Add bio to back of pending list
484 static void loop_add_bio(struct loop_device
*lo
, struct bio
*bio
)
486 if (lo
->lo_biotail
) {
487 lo
->lo_biotail
->bi_next
= bio
;
488 lo
->lo_biotail
= bio
;
490 lo
->lo_bio
= lo
->lo_biotail
= bio
;
494 * Grab first pending buffer
496 static struct bio
*loop_get_bio(struct loop_device
*lo
)
500 if ((bio
= lo
->lo_bio
)) {
501 if (bio
== lo
->lo_biotail
)
502 lo
->lo_biotail
= NULL
;
503 lo
->lo_bio
= bio
->bi_next
;
510 static int loop_make_request(request_queue_t
*q
, struct bio
*old_bio
)
512 struct loop_device
*lo
= q
->queuedata
;
513 int rw
= bio_rw(old_bio
);
518 BUG_ON(!lo
|| (rw
!= READ
&& rw
!= WRITE
));
520 spin_lock_irq(&lo
->lo_lock
);
521 if (lo
->lo_state
!= Lo_bound
)
523 if (unlikely(rw
== WRITE
&& (lo
->lo_flags
& LO_FLAGS_READ_ONLY
)))
526 loop_add_bio(lo
, old_bio
);
527 spin_unlock_irq(&lo
->lo_lock
);
528 complete(&lo
->lo_bh_done
);
532 if (lo
->lo_pending
== 0)
533 complete(&lo
->lo_bh_done
);
534 spin_unlock_irq(&lo
->lo_lock
);
535 bio_io_error(old_bio
, old_bio
->bi_size
);
540 * kick off io on the underlying address space
542 static void loop_unplug(request_queue_t
*q
)
544 struct loop_device
*lo
= q
->queuedata
;
546 clear_bit(QUEUE_FLAG_PLUGGED
, &q
->queue_flags
);
547 blk_run_address_space(lo
->lo_backing_file
->f_mapping
);
550 struct switch_request
{
552 struct completion wait
;
555 static void do_loop_switch(struct loop_device
*, struct switch_request
*);
557 static inline void loop_handle_bio(struct loop_device
*lo
, struct bio
*bio
)
559 if (unlikely(!bio
->bi_bdev
)) {
560 do_loop_switch(lo
, bio
->bi_private
);
563 int ret
= do_bio_filebacked(lo
, bio
);
564 bio_endio(bio
, bio
->bi_size
, ret
);
569 * worker thread that handles reads/writes to file backed loop devices,
570 * to avoid blocking in our make_request_fn. it also does loop decrypting
571 * on reads for block backed loop, as that is too heavy to do from
572 * b_end_io context where irqs may be disabled.
574 static int loop_thread(void *data
)
576 struct loop_device
*lo
= data
;
579 daemonize("loop%d", lo
->lo_number
);
582 * loop can be used in an encrypted device,
583 * hence, it mustn't be stopped at all
584 * because it could be indirectly used during suspension
586 current
->flags
|= PF_NOFREEZE
;
588 set_user_nice(current
, -20);
590 lo
->lo_state
= Lo_bound
;
594 * complete it, we are running
596 complete(&lo
->lo_done
);
601 if (wait_for_completion_interruptible(&lo
->lo_bh_done
))
604 spin_lock_irq(&lo
->lo_lock
);
607 * could be completed because of tear-down, not pending work
609 if (unlikely(!lo
->lo_pending
)) {
610 spin_unlock_irq(&lo
->lo_lock
);
614 bio
= loop_get_bio(lo
);
616 pending
= lo
->lo_pending
;
617 spin_unlock_irq(&lo
->lo_lock
);
620 loop_handle_bio(lo
, bio
);
623 * upped both for pending work and tear-down, lo_pending
626 if (unlikely(!pending
))
630 complete(&lo
->lo_done
);
635 * loop_switch performs the hard work of switching a backing store.
636 * First it needs to flush existing IO, it does this by sending a magic
637 * BIO down the pipe. The completion of this BIO does the actual switch.
639 static int loop_switch(struct loop_device
*lo
, struct file
*file
)
641 struct switch_request w
;
642 struct bio
*bio
= bio_alloc(GFP_KERNEL
, 1);
645 init_completion(&w
.wait
);
647 bio
->bi_private
= &w
;
649 loop_make_request(lo
->lo_queue
, bio
);
650 wait_for_completion(&w
.wait
);
655 * Do the actual switch; called from the BIO completion routine
657 static void do_loop_switch(struct loop_device
*lo
, struct switch_request
*p
)
659 struct file
*file
= p
->file
;
660 struct file
*old_file
= lo
->lo_backing_file
;
661 struct address_space
*mapping
= file
->f_mapping
;
663 mapping_set_gfp_mask(old_file
->f_mapping
, lo
->old_gfp_mask
);
664 lo
->lo_backing_file
= file
;
665 lo
->lo_blocksize
= mapping
->host
->i_blksize
;
666 lo
->old_gfp_mask
= mapping_gfp_mask(mapping
);
667 mapping_set_gfp_mask(mapping
, lo
->old_gfp_mask
& ~(__GFP_IO
|__GFP_FS
));
673 * loop_change_fd switched the backing store of a loopback device to
674 * a new file. This is useful for operating system installers to free up
675 * the original file and in High Availability environments to switch to
676 * an alternative location for the content in case of server meltdown.
677 * This can only work if the loop device is used read-only, and if the
678 * new backing store is the same size and type as the old backing store.
680 static int loop_change_fd(struct loop_device
*lo
, struct file
*lo_file
,
681 struct block_device
*bdev
, unsigned int arg
)
683 struct file
*file
, *old_file
;
688 if (lo
->lo_state
!= Lo_bound
)
691 /* the loop device has to be read-only */
693 if (!(lo
->lo_flags
& LO_FLAGS_READ_ONLY
))
701 inode
= file
->f_mapping
->host
;
702 old_file
= lo
->lo_backing_file
;
706 if (!S_ISREG(inode
->i_mode
) && !S_ISBLK(inode
->i_mode
))
709 /* new backing store needs to support loop (eg sendfile) */
710 if (!inode
->i_fop
->sendfile
)
713 /* size of the new backing store needs to be the same */
714 if (get_loop_size(lo
, file
) != get_loop_size(lo
, old_file
))
718 error
= loop_switch(lo
, file
);
731 static inline int is_loop_device(struct file
*file
)
733 struct inode
*i
= file
->f_mapping
->host
;
735 return i
&& S_ISBLK(i
->i_mode
) && MAJOR(i
->i_rdev
) == LOOP_MAJOR
;
738 static int loop_set_fd(struct loop_device
*lo
, struct file
*lo_file
,
739 struct block_device
*bdev
, unsigned int arg
)
741 struct file
*file
, *f
;
743 struct address_space
*mapping
;
744 unsigned lo_blocksize
;
749 /* This is safe, since we have a reference from open(). */
750 __module_get(THIS_MODULE
);
758 if (lo
->lo_state
!= Lo_unbound
)
761 /* Avoid recursion */
763 while (is_loop_device(f
)) {
764 struct loop_device
*l
;
766 if (f
->f_mapping
->host
->i_rdev
== lo_file
->f_mapping
->host
->i_rdev
)
769 l
= f
->f_mapping
->host
->i_bdev
->bd_disk
->private_data
;
770 if (l
->lo_state
== Lo_unbound
) {
774 f
= l
->lo_backing_file
;
777 mapping
= file
->f_mapping
;
778 inode
= mapping
->host
;
780 if (!(file
->f_mode
& FMODE_WRITE
))
781 lo_flags
|= LO_FLAGS_READ_ONLY
;
784 if (S_ISREG(inode
->i_mode
) || S_ISBLK(inode
->i_mode
)) {
785 const struct address_space_operations
*aops
= mapping
->a_ops
;
787 * If we can't read - sorry. If we only can't write - well,
788 * it's going to be read-only.
790 if (!file
->f_op
->sendfile
)
792 if (aops
->prepare_write
&& aops
->commit_write
)
793 lo_flags
|= LO_FLAGS_USE_AOPS
;
794 if (!(lo_flags
& LO_FLAGS_USE_AOPS
) && !file
->f_op
->write
)
795 lo_flags
|= LO_FLAGS_READ_ONLY
;
797 lo_blocksize
= inode
->i_blksize
;
803 size
= get_loop_size(lo
, file
);
805 if ((loff_t
)(sector_t
)size
!= size
) {
810 if (!(lo_file
->f_mode
& FMODE_WRITE
))
811 lo_flags
|= LO_FLAGS_READ_ONLY
;
813 set_device_ro(bdev
, (lo_flags
& LO_FLAGS_READ_ONLY
) != 0);
815 lo
->lo_blocksize
= lo_blocksize
;
816 lo
->lo_device
= bdev
;
817 lo
->lo_flags
= lo_flags
;
818 lo
->lo_backing_file
= file
;
819 lo
->transfer
= transfer_none
;
821 lo
->lo_sizelimit
= 0;
822 lo
->old_gfp_mask
= mapping_gfp_mask(mapping
);
823 mapping_set_gfp_mask(mapping
, lo
->old_gfp_mask
& ~(__GFP_IO
|__GFP_FS
));
825 lo
->lo_bio
= lo
->lo_biotail
= NULL
;
828 * set queue make_request_fn, and add limits based on lower level
831 blk_queue_make_request(lo
->lo_queue
, loop_make_request
);
832 lo
->lo_queue
->queuedata
= lo
;
833 lo
->lo_queue
->unplug_fn
= loop_unplug
;
835 set_capacity(disks
[lo
->lo_number
], size
);
836 bd_set_size(bdev
, size
<< 9);
838 set_blocksize(bdev
, lo_blocksize
);
840 error
= kernel_thread(loop_thread
, lo
, CLONE_KERNEL
);
843 wait_for_completion(&lo
->lo_done
);
849 /* This is safe: open() is still holding a reference. */
850 module_put(THIS_MODULE
);
855 loop_release_xfer(struct loop_device
*lo
)
858 struct loop_func_table
*xfer
= lo
->lo_encryption
;
862 err
= xfer
->release(lo
);
864 lo
->lo_encryption
= NULL
;
865 module_put(xfer
->owner
);
871 loop_init_xfer(struct loop_device
*lo
, struct loop_func_table
*xfer
,
872 const struct loop_info64
*i
)
877 struct module
*owner
= xfer
->owner
;
879 if (!try_module_get(owner
))
882 err
= xfer
->init(lo
, i
);
886 lo
->lo_encryption
= xfer
;
891 static int loop_clr_fd(struct loop_device
*lo
, struct block_device
*bdev
)
893 struct file
*filp
= lo
->lo_backing_file
;
894 gfp_t gfp
= lo
->old_gfp_mask
;
896 if (lo
->lo_state
!= Lo_bound
)
899 if (lo
->lo_refcnt
> 1) /* we needed one fd for the ioctl */
905 spin_lock_irq(&lo
->lo_lock
);
906 lo
->lo_state
= Lo_rundown
;
909 complete(&lo
->lo_bh_done
);
910 spin_unlock_irq(&lo
->lo_lock
);
912 wait_for_completion(&lo
->lo_done
);
914 lo
->lo_backing_file
= NULL
;
916 loop_release_xfer(lo
);
919 lo
->lo_device
= NULL
;
920 lo
->lo_encryption
= NULL
;
922 lo
->lo_sizelimit
= 0;
923 lo
->lo_encrypt_key_size
= 0;
925 memset(lo
->lo_encrypt_key
, 0, LO_KEY_SIZE
);
926 memset(lo
->lo_crypt_name
, 0, LO_NAME_SIZE
);
927 memset(lo
->lo_file_name
, 0, LO_NAME_SIZE
);
928 invalidate_bdev(bdev
, 0);
929 set_capacity(disks
[lo
->lo_number
], 0);
930 bd_set_size(bdev
, 0);
931 mapping_set_gfp_mask(filp
->f_mapping
, gfp
);
932 lo
->lo_state
= Lo_unbound
;
934 /* This is safe: open() is still holding a reference. */
935 module_put(THIS_MODULE
);
940 loop_set_status(struct loop_device
*lo
, const struct loop_info64
*info
)
943 struct loop_func_table
*xfer
;
945 if (lo
->lo_encrypt_key_size
&& lo
->lo_key_owner
!= current
->uid
&&
946 !capable(CAP_SYS_ADMIN
))
948 if (lo
->lo_state
!= Lo_bound
)
950 if ((unsigned int) info
->lo_encrypt_key_size
> LO_KEY_SIZE
)
953 err
= loop_release_xfer(lo
);
957 if (info
->lo_encrypt_type
) {
958 unsigned int type
= info
->lo_encrypt_type
;
960 if (type
>= MAX_LO_CRYPT
)
962 xfer
= xfer_funcs
[type
];
968 err
= loop_init_xfer(lo
, xfer
, info
);
972 if (lo
->lo_offset
!= info
->lo_offset
||
973 lo
->lo_sizelimit
!= info
->lo_sizelimit
) {
974 lo
->lo_offset
= info
->lo_offset
;
975 lo
->lo_sizelimit
= info
->lo_sizelimit
;
976 if (figure_loop_size(lo
))
980 memcpy(lo
->lo_file_name
, info
->lo_file_name
, LO_NAME_SIZE
);
981 memcpy(lo
->lo_crypt_name
, info
->lo_crypt_name
, LO_NAME_SIZE
);
982 lo
->lo_file_name
[LO_NAME_SIZE
-1] = 0;
983 lo
->lo_crypt_name
[LO_NAME_SIZE
-1] = 0;
987 lo
->transfer
= xfer
->transfer
;
988 lo
->ioctl
= xfer
->ioctl
;
990 lo
->lo_encrypt_key_size
= info
->lo_encrypt_key_size
;
991 lo
->lo_init
[0] = info
->lo_init
[0];
992 lo
->lo_init
[1] = info
->lo_init
[1];
993 if (info
->lo_encrypt_key_size
) {
994 memcpy(lo
->lo_encrypt_key
, info
->lo_encrypt_key
,
995 info
->lo_encrypt_key_size
);
996 lo
->lo_key_owner
= current
->uid
;
1003 loop_get_status(struct loop_device
*lo
, struct loop_info64
*info
)
1005 struct file
*file
= lo
->lo_backing_file
;
1009 if (lo
->lo_state
!= Lo_bound
)
1011 error
= vfs_getattr(file
->f_vfsmnt
, file
->f_dentry
, &stat
);
1014 memset(info
, 0, sizeof(*info
));
1015 info
->lo_number
= lo
->lo_number
;
1016 info
->lo_device
= huge_encode_dev(stat
.dev
);
1017 info
->lo_inode
= stat
.ino
;
1018 info
->lo_rdevice
= huge_encode_dev(lo
->lo_device
? stat
.rdev
: stat
.dev
);
1019 info
->lo_offset
= lo
->lo_offset
;
1020 info
->lo_sizelimit
= lo
->lo_sizelimit
;
1021 info
->lo_flags
= lo
->lo_flags
;
1022 memcpy(info
->lo_file_name
, lo
->lo_file_name
, LO_NAME_SIZE
);
1023 memcpy(info
->lo_crypt_name
, lo
->lo_crypt_name
, LO_NAME_SIZE
);
1024 info
->lo_encrypt_type
=
1025 lo
->lo_encryption
? lo
->lo_encryption
->number
: 0;
1026 if (lo
->lo_encrypt_key_size
&& capable(CAP_SYS_ADMIN
)) {
1027 info
->lo_encrypt_key_size
= lo
->lo_encrypt_key_size
;
1028 memcpy(info
->lo_encrypt_key
, lo
->lo_encrypt_key
,
1029 lo
->lo_encrypt_key_size
);
1035 loop_info64_from_old(const struct loop_info
*info
, struct loop_info64
*info64
)
1037 memset(info64
, 0, sizeof(*info64
));
1038 info64
->lo_number
= info
->lo_number
;
1039 info64
->lo_device
= info
->lo_device
;
1040 info64
->lo_inode
= info
->lo_inode
;
1041 info64
->lo_rdevice
= info
->lo_rdevice
;
1042 info64
->lo_offset
= info
->lo_offset
;
1043 info64
->lo_sizelimit
= 0;
1044 info64
->lo_encrypt_type
= info
->lo_encrypt_type
;
1045 info64
->lo_encrypt_key_size
= info
->lo_encrypt_key_size
;
1046 info64
->lo_flags
= info
->lo_flags
;
1047 info64
->lo_init
[0] = info
->lo_init
[0];
1048 info64
->lo_init
[1] = info
->lo_init
[1];
1049 if (info
->lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
1050 memcpy(info64
->lo_crypt_name
, info
->lo_name
, LO_NAME_SIZE
);
1052 memcpy(info64
->lo_file_name
, info
->lo_name
, LO_NAME_SIZE
);
1053 memcpy(info64
->lo_encrypt_key
, info
->lo_encrypt_key
, LO_KEY_SIZE
);
1057 loop_info64_to_old(const struct loop_info64
*info64
, struct loop_info
*info
)
1059 memset(info
, 0, sizeof(*info
));
1060 info
->lo_number
= info64
->lo_number
;
1061 info
->lo_device
= info64
->lo_device
;
1062 info
->lo_inode
= info64
->lo_inode
;
1063 info
->lo_rdevice
= info64
->lo_rdevice
;
1064 info
->lo_offset
= info64
->lo_offset
;
1065 info
->lo_encrypt_type
= info64
->lo_encrypt_type
;
1066 info
->lo_encrypt_key_size
= info64
->lo_encrypt_key_size
;
1067 info
->lo_flags
= info64
->lo_flags
;
1068 info
->lo_init
[0] = info64
->lo_init
[0];
1069 info
->lo_init
[1] = info64
->lo_init
[1];
1070 if (info
->lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
1071 memcpy(info
->lo_name
, info64
->lo_crypt_name
, LO_NAME_SIZE
);
1073 memcpy(info
->lo_name
, info64
->lo_file_name
, LO_NAME_SIZE
);
1074 memcpy(info
->lo_encrypt_key
, info64
->lo_encrypt_key
, LO_KEY_SIZE
);
1076 /* error in case values were truncated */
1077 if (info
->lo_device
!= info64
->lo_device
||
1078 info
->lo_rdevice
!= info64
->lo_rdevice
||
1079 info
->lo_inode
!= info64
->lo_inode
||
1080 info
->lo_offset
!= info64
->lo_offset
)
1087 loop_set_status_old(struct loop_device
*lo
, const struct loop_info __user
*arg
)
1089 struct loop_info info
;
1090 struct loop_info64 info64
;
1092 if (copy_from_user(&info
, arg
, sizeof (struct loop_info
)))
1094 loop_info64_from_old(&info
, &info64
);
1095 return loop_set_status(lo
, &info64
);
1099 loop_set_status64(struct loop_device
*lo
, const struct loop_info64 __user
*arg
)
1101 struct loop_info64 info64
;
1103 if (copy_from_user(&info64
, arg
, sizeof (struct loop_info64
)))
1105 return loop_set_status(lo
, &info64
);
1109 loop_get_status_old(struct loop_device
*lo
, struct loop_info __user
*arg
) {
1110 struct loop_info info
;
1111 struct loop_info64 info64
;
1117 err
= loop_get_status(lo
, &info64
);
1119 err
= loop_info64_to_old(&info64
, &info
);
1120 if (!err
&& copy_to_user(arg
, &info
, sizeof(info
)))
1127 loop_get_status64(struct loop_device
*lo
, struct loop_info64 __user
*arg
) {
1128 struct loop_info64 info64
;
1134 err
= loop_get_status(lo
, &info64
);
1135 if (!err
&& copy_to_user(arg
, &info64
, sizeof(info64
)))
1141 static int lo_ioctl(struct inode
* inode
, struct file
* file
,
1142 unsigned int cmd
, unsigned long arg
)
1144 struct loop_device
*lo
= inode
->i_bdev
->bd_disk
->private_data
;
1147 mutex_lock(&lo
->lo_ctl_mutex
);
1150 err
= loop_set_fd(lo
, file
, inode
->i_bdev
, arg
);
1152 case LOOP_CHANGE_FD
:
1153 err
= loop_change_fd(lo
, file
, inode
->i_bdev
, arg
);
1156 err
= loop_clr_fd(lo
, inode
->i_bdev
);
1158 case LOOP_SET_STATUS
:
1159 err
= loop_set_status_old(lo
, (struct loop_info __user
*) arg
);
1161 case LOOP_GET_STATUS
:
1162 err
= loop_get_status_old(lo
, (struct loop_info __user
*) arg
);
1164 case LOOP_SET_STATUS64
:
1165 err
= loop_set_status64(lo
, (struct loop_info64 __user
*) arg
);
1167 case LOOP_GET_STATUS64
:
1168 err
= loop_get_status64(lo
, (struct loop_info64 __user
*) arg
);
1171 err
= lo
->ioctl
? lo
->ioctl(lo
, cmd
, arg
) : -EINVAL
;
1173 mutex_unlock(&lo
->lo_ctl_mutex
);
1177 static int lo_open(struct inode
*inode
, struct file
*file
)
1179 struct loop_device
*lo
= inode
->i_bdev
->bd_disk
->private_data
;
1181 mutex_lock(&lo
->lo_ctl_mutex
);
1183 mutex_unlock(&lo
->lo_ctl_mutex
);
1188 static int lo_release(struct inode
*inode
, struct file
*file
)
1190 struct loop_device
*lo
= inode
->i_bdev
->bd_disk
->private_data
;
1192 mutex_lock(&lo
->lo_ctl_mutex
);
1194 mutex_unlock(&lo
->lo_ctl_mutex
);
1199 static struct block_device_operations lo_fops
= {
1200 .owner
= THIS_MODULE
,
1202 .release
= lo_release
,
1207 * And now the modules code and kernel interface.
1209 module_param(max_loop
, int, 0);
1210 MODULE_PARM_DESC(max_loop
, "Maximum number of loop devices (1-256)");
1211 MODULE_LICENSE("GPL");
1212 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR
);
1214 int loop_register_transfer(struct loop_func_table
*funcs
)
1216 unsigned int n
= funcs
->number
;
1218 if (n
>= MAX_LO_CRYPT
|| xfer_funcs
[n
])
1220 xfer_funcs
[n
] = funcs
;
1224 int loop_unregister_transfer(int number
)
1226 unsigned int n
= number
;
1227 struct loop_device
*lo
;
1228 struct loop_func_table
*xfer
;
1230 if (n
== 0 || n
>= MAX_LO_CRYPT
|| (xfer
= xfer_funcs
[n
]) == NULL
)
1233 xfer_funcs
[n
] = NULL
;
1235 for (lo
= &loop_dev
[0]; lo
< &loop_dev
[max_loop
]; lo
++) {
1236 mutex_lock(&lo
->lo_ctl_mutex
);
1238 if (lo
->lo_encryption
== xfer
)
1239 loop_release_xfer(lo
);
1241 mutex_unlock(&lo
->lo_ctl_mutex
);
1247 EXPORT_SYMBOL(loop_register_transfer
);
1248 EXPORT_SYMBOL(loop_unregister_transfer
);
1250 static int __init
loop_init(void)
1254 if (max_loop
< 1 || max_loop
> 256) {
1255 printk(KERN_WARNING
"loop: invalid max_loop (must be between"
1256 " 1 and 256), using default (8)\n");
1260 if (register_blkdev(LOOP_MAJOR
, "loop"))
1263 loop_dev
= kmalloc(max_loop
* sizeof(struct loop_device
), GFP_KERNEL
);
1266 memset(loop_dev
, 0, max_loop
* sizeof(struct loop_device
));
1268 disks
= kmalloc(max_loop
* sizeof(struct gendisk
*), GFP_KERNEL
);
1272 for (i
= 0; i
< max_loop
; i
++) {
1273 disks
[i
] = alloc_disk(1);
1278 for (i
= 0; i
< max_loop
; i
++) {
1279 struct loop_device
*lo
= &loop_dev
[i
];
1280 struct gendisk
*disk
= disks
[i
];
1282 memset(lo
, 0, sizeof(*lo
));
1283 lo
->lo_queue
= blk_alloc_queue(GFP_KERNEL
);
1286 mutex_init(&lo
->lo_ctl_mutex
);
1287 init_completion(&lo
->lo_done
);
1288 init_completion(&lo
->lo_bh_done
);
1290 spin_lock_init(&lo
->lo_lock
);
1291 disk
->major
= LOOP_MAJOR
;
1292 disk
->first_minor
= i
;
1293 disk
->fops
= &lo_fops
;
1294 sprintf(disk
->disk_name
, "loop%d", i
);
1295 disk
->private_data
= lo
;
1296 disk
->queue
= lo
->lo_queue
;
1299 /* We cannot fail after we call this, so another loop!*/
1300 for (i
= 0; i
< max_loop
; i
++)
1302 printk(KERN_INFO
"loop: loaded (max %d devices)\n", max_loop
);
1307 blk_cleanup_queue(loop_dev
[i
].lo_queue
);
1316 unregister_blkdev(LOOP_MAJOR
, "loop");
1317 printk(KERN_ERR
"loop: ran out of memory\n");
1321 static void loop_exit(void)
1325 for (i
= 0; i
< max_loop
; i
++) {
1326 del_gendisk(disks
[i
]);
1327 blk_cleanup_queue(loop_dev
[i
].lo_queue
);
1330 if (unregister_blkdev(LOOP_MAJOR
, "loop"))
1331 printk(KERN_WARNING
"loop: cannot unregister blkdev\n");
1337 module_init(loop_init
);
1338 module_exit(loop_exit
);
1341 static int __init
max_loop_setup(char *str
)
1343 max_loop
= simple_strtol(str
, NULL
, 0);
1347 __setup("max_loop=", max_loop_setup
);