/*
* linux/drivers/block/loop.c
*
* Written by Theodore Ts'o, 3/29/93
*
* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
* permitted under the GNU General Public License.
*
* DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
* more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
*
* Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
* Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
*
* Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
*
* Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
*
* Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
*
* Loadable modules and other fixes by AK, 1998
*
* Make real block number available to downstream transfer functions, enables
* CBC (and relatives) mode encryption requiring unique IVs per data block.
* Reed H. Petty, rhp@draper.net
*
* Maximum number of loop devices now dynamic via max_loop module parameter.
* Russell Kroll <rkroll@exploits.org> 19990701
*
* Maximum number of loop devices when compiled-in now selectable by passing
* max_loop=<1-255> to the kernel on boot.
* Erik I. Bolsų, <eriki@himolde.no>, Oct 31, 1999
*
* Completely rewrite request handling to be make_request_fn style and
* non blocking, pushing work to a helper thread. Lots of fixes from
* Al Viro too.
* Jens Axboe <axboe@suse.de>, Nov 2000
*
* Support up to 256 loop devices
* Heinz Mauelshagen <mge@sistina.com>, Feb 2002
*
* Still To Fix:
* - Advisory locking is ignored here.
* - Should use an own CAP_* category instead of CAP_SYS_ADMIN
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/major.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/init.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/smp_lock.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/loop.h>
#include <linux/suspend.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* for invalidate_bdev() */
#include <asm/uaccess.h>
static int max_loop = 8;
static struct loop_device *loop_dev;
static struct gendisk **disks;
/*
* Transfer functions
*/
static int transfer_none(struct loop_device *lo, int cmd, char *raw_buf,
char *loop_buf, int size, sector_t real_block)
{
if (raw_buf != loop_buf) {
if (cmd == READ)
memcpy(loop_buf, raw_buf, size);
else
memcpy(raw_buf, loop_buf, size);
}
return 0;
}
static int transfer_xor(struct loop_device *lo, int cmd, char *raw_buf,
char *loop_buf, int size, sector_t real_block)
{
char *in, *out, *key;
int i, keysize;
if (cmd == READ) {
in = raw_buf;
out = loop_buf;
} else {
in = loop_buf;
out = raw_buf;
}
key = lo->lo_encrypt_key;
keysize = lo->lo_encrypt_key_size;
for (i = 0; i < size; i++)
*out++ = *in++ ^ key[(i & 511) % keysize];
return 0;
}
static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
{
if (info->lo_encrypt_key_size <= 0)
return -EINVAL;
return 0;
}
static struct loop_func_table none_funcs = {
.number = LO_CRYPT_NONE,
.transfer = transfer_none,
};
static struct loop_func_table xor_funcs = {
.number = LO_CRYPT_XOR,
.transfer = transfer_xor,
.init = xor_init
};
/* xfer_funcs[0] is special - its release function is never called */
static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
&none_funcs,
&xor_funcs
};
static int
figure_loop_size(struct loop_device *lo)
{
loff_t size, offset, loopsize;
sector_t x;
/* Compute loopsize in bytes */
size = i_size_read(lo->lo_backing_file->f_mapping->host);
offset = lo->lo_offset;
loopsize = size - offset;
if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
loopsize = lo->lo_sizelimit;
/*
* Unfortunately, if we want to do I/O on the device,
* the number of 512-byte sectors has to fit into a sector_t.
*/
size = loopsize >> 9;
x = (sector_t)size;
if ((loff_t)x != size)
return -EFBIG;
set_capacity(disks[lo->lo_number], x);
return 0;
}
static inline int
lo_do_transfer(struct loop_device *lo, int cmd, char *rbuf,
char *lbuf, int size, sector_t rblock)
{
if (!lo->transfer)
return 0;
return lo->transfer(lo, cmd, rbuf, lbuf, size, rblock);
}
static int
do_lo_send(struct loop_device *lo, struct bio_vec *bvec, int bsize, loff_t pos)
{
struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
struct address_space *mapping = file->f_mapping;
struct address_space_operations *aops = mapping->a_ops;
struct page *page;
char *kaddr, *data;
pgoff_t index;
unsigned size, offset;
int len;
int ret = 0;
down(&mapping->host->i_sem);
index = pos >> PAGE_CACHE_SHIFT;
offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1);
data = kmap(bvec->bv_page) + bvec->bv_offset;
len = bvec->bv_len;
while (len > 0) {
sector_t IV;
int transfer_result;
IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
size = PAGE_CACHE_SIZE - offset;
if (size > len)
size = len;
page = grab_cache_page(mapping, index);
if (!page)
goto fail;
if (aops->prepare_write(file, page, offset, offset+size))
goto unlock;
kaddr = kmap(page);
transfer_result = lo_do_transfer(lo, WRITE, kaddr + offset,
data, size, IV);
if (transfer_result) {
/*
* The transfer failed, but we still write the data to
* keep prepare/commit calls balanced.
*/
printk(KERN_ERR "loop: transfer error block %llu\n",
(unsigned long long)index);
memset(kaddr + offset, 0, size);
}
flush_dcache_page(page);
kunmap(page);
if (aops->commit_write(file, page, offset, offset+size))
goto unlock;
if (transfer_result)
goto unlock;
data += size;
len -= size;
offset = 0;
index++;
pos += size;
unlock_page(page);
page_cache_release(page);
}
up(&mapping->host->i_sem);
out:
kunmap(bvec->bv_page);
return ret;
unlock:
unlock_page(page);
page_cache_release(page);
fail:
up(&mapping->host->i_sem);
ret = -1;
goto out;
}
static int
lo_send(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
{
unsigned vecnr;
int ret = 0;
for (vecnr = 0; vecnr < bio->bi_vcnt; vecnr++) {
struct bio_vec *bvec = &bio->bi_io_vec[vecnr];
ret = do_lo_send(lo, bvec, bsize, pos);
if (ret < 0)
break;
pos += bvec->bv_len;
}
return ret;
}
struct lo_read_data {
struct loop_device *lo;
char *data;
int bsize;
};
static int
lo_read_actor(read_descriptor_t *desc, struct page *page,
unsigned long offset, unsigned long size)
{
char *kaddr;
unsigned long count = desc->count;
struct lo_read_data *p = (struct lo_read_data*)desc->buf;
struct loop_device *lo = p->lo;
sector_t IV;
IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
if (size > count)
size = count;
kaddr = kmap(page);
if (lo_do_transfer(lo, READ, kaddr + offset, p->data, size, IV)) {
size = 0;
printk(KERN_ERR "loop: transfer error block %ld\n",
page->index);
desc->error = -EINVAL;
}
kunmap(page);
desc->count = count - size;
desc->written += size;
p->data += size;
return size;
}
static int
do_lo_receive(struct loop_device *lo,
struct bio_vec *bvec, int bsize, loff_t pos)
{
struct lo_read_data cookie;
struct file *file;
int retval;
cookie.lo = lo;
cookie.data = kmap(bvec->bv_page) + bvec->bv_offset;
cookie.bsize = bsize;
file = lo->lo_backing_file;
retval = file->f_op->sendfile(file, &pos, bvec->bv_len,
lo_read_actor, &cookie);
kunmap(bvec->bv_page);
return (retval < 0)? retval: 0;
}
static int
lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
{
unsigned vecnr;
int ret = 0;
for (vecnr = 0; vecnr < bio->bi_vcnt; vecnr++) {
struct bio_vec *bvec = &bio->bi_io_vec[vecnr];
ret = do_lo_receive(lo, bvec, bsize, pos);
if (ret < 0)
break;
pos += bvec->bv_len;
}
return ret;
}
static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
{
loff_t pos;
int ret;
pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset;
if (bio_rw(bio) == WRITE)
ret = lo_send(lo, bio, lo->lo_blocksize, pos);
else
ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
return ret;
}
static int loop_end_io_transfer(struct bio *, unsigned int, int);
static void loop_put_buffer(struct bio *bio)
{
/*
* check bi_end_io, may just be a remapped bio
*/
if (bio && bio->bi_end_io == loop_end_io_transfer) {
int i;
for (i = 0; i < bio->bi_vcnt; i++)
__free_page(bio->bi_io_vec[i].bv_page);
bio_put(bio);
}
}
/*
* Add bio to back of pending list
*/
static void loop_add_bio(struct loop_device *lo, struct bio *bio)
{
unsigned long flags;
spin_lock_irqsave(&lo->lo_lock, flags);
if (lo->lo_biotail) {
lo->lo_biotail->bi_next = bio;
lo->lo_biotail = bio;
} else
lo->lo_bio = lo->lo_biotail = bio;
spin_unlock_irqrestore(&lo->lo_lock, flags);
up(&lo->lo_bh_mutex);
}
/*
* Grab first pending buffer
*/
static struct bio *loop_get_bio(struct loop_device *lo)
{
struct bio *bio;
spin_lock_irq(&lo->lo_lock);
if ((bio = lo->lo_bio)) {
if (bio == lo->lo_biotail)
lo->lo_biotail = NULL;
lo->lo_bio = bio->bi_next;
bio->bi_next = NULL;
}
spin_unlock_irq(&lo->lo_lock);
return bio;
}
/*
* if this was a WRITE lo->transfer stuff has already been done. for READs,
* queue it for the loop thread and let it do the transfer out of
* bi_end_io context (we don't want to do decrypt of a page with irqs
* disabled)
*/
static int loop_end_io_transfer(struct bio *bio, unsigned int bytes_done, int err)
{
struct bio *rbh = bio->bi_private;
struct loop_device *lo = rbh->bi_bdev->bd_disk->private_data;
if (bio->bi_size)
return 1;
if (err || bio_rw(bio) == WRITE) {
bio_endio(rbh, rbh->bi_size, err);
if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex);
loop_put_buffer(bio);
} else
loop_add_bio(lo, bio);
return 0;
}
static struct bio *loop_copy_bio(struct bio *rbh)
{
struct bio *bio;
struct bio_vec *bv;
int i;
bio = bio_alloc(__GFP_NOWARN, rbh->bi_vcnt);
if (!bio)
return NULL;
/*
* iterate iovec list and alloc pages
*/
__bio_for_each_segment(bv, rbh, i, 0) {
struct bio_vec *bbv = &bio->bi_io_vec[i];
bbv->bv_page = alloc_page(__GFP_NOWARN|__GFP_HIGHMEM);
if (bbv->bv_page == NULL)
goto oom;
bbv->bv_len = bv->bv_len;
bbv->bv_offset = bv->bv_offset;
}
bio->bi_vcnt = rbh->bi_vcnt;
bio->bi_size = rbh->bi_size;
return bio;
oom:
while (--i >= 0)
__free_page(bio->bi_io_vec[i].bv_page);
bio_put(bio);
return NULL;
}
static struct bio *loop_get_buffer(struct loop_device *lo, struct bio *rbh)
{
struct bio *bio;
/*
* When called on the page reclaim -> writepage path, this code can
* trivially consume all memory. So we drop PF_MEMALLOC to avoid
* stealing all the page reserves and throttle to the writeout rate.
* pdflush will have been woken by page reclaim. Let it do its work.
*/
do {
int flags = current->flags;
current->flags &= ~PF_MEMALLOC;
bio = loop_copy_bio(rbh);
if (flags & PF_MEMALLOC)
current->flags |= PF_MEMALLOC;
if (bio == NULL)
blk_congestion_wait(WRITE, HZ/10);
} while (bio == NULL);
bio->bi_end_io = loop_end_io_transfer;
bio->bi_private = rbh;
bio->bi_sector = rbh->bi_sector + (lo->lo_offset >> 9);
bio->bi_rw = rbh->bi_rw;
bio->bi_bdev = lo->lo_device;
return bio;
}
static int loop_transfer_bio(struct loop_device *lo,
struct bio *to_bio, struct bio *from_bio)
{
sector_t IV;
struct bio_vec *from_bvec, *to_bvec;
char *vto, *vfrom;
int ret = 0, i;
IV = from_bio->bi_sector + (lo->lo_offset >> 9);
__bio_for_each_segment(from_bvec, from_bio, i, 0) {
to_bvec = &to_bio->bi_io_vec[i];
kmap(from_bvec->bv_page);
kmap(to_bvec->bv_page);
vfrom = page_address(from_bvec->bv_page) + from_bvec->bv_offset;
vto = page_address(to_bvec->bv_page) + to_bvec->bv_offset;
ret |= lo_do_transfer(lo, bio_data_dir(to_bio), vto, vfrom,
from_bvec->bv_len, IV);
kunmap(from_bvec->bv_page);
kunmap(to_bvec->bv_page);
IV += from_bvec->bv_len >> 9;
}
return ret;
}
static int loop_make_request(request_queue_t *q, struct bio *old_bio)
{
struct bio *new_bio = NULL;
struct loop_device *lo = q->queuedata;
int rw = bio_rw(old_bio);
if (!lo)
goto out;
spin_lock_irq(&lo->lo_lock);
if (lo->lo_state != Lo_bound)
goto inactive;
atomic_inc(&lo->lo_pending);
spin_unlock_irq(&lo->lo_lock);
if (rw == WRITE) {
if (lo->lo_flags & LO_FLAGS_READ_ONLY)
goto err;
} else if (rw == READA) {
rw = READ;
} else if (rw != READ) {
printk(KERN_ERR "loop: unknown command (%x)\n", rw);
goto err;
}
/*
* file backed, queue for loop_thread to handle
*/
if (lo->lo_flags & LO_FLAGS_DO_BMAP) {
loop_add_bio(lo, old_bio);
return 0;
}
/*
* piggy old buffer on original, and submit for I/O
*/
new_bio = loop_get_buffer(lo, old_bio);
if (rw == WRITE) {
if (loop_transfer_bio(lo, new_bio, old_bio))
goto err;
}
generic_make_request(new_bio);
return 0;
err:
if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex);
loop_put_buffer(new_bio);
out:
bio_io_error(old_bio, old_bio->bi_size);
return 0;
inactive:
spin_unlock_irq(&lo->lo_lock);
goto out;
}
static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio)
{
int ret;
/*
* For block backed loop, we know this is a READ
*/
if (lo->lo_flags & LO_FLAGS_DO_BMAP) {
ret = do_bio_filebacked(lo, bio);
bio_endio(bio, bio->bi_size, ret);
} else {
struct bio *rbh = bio->bi_private;
ret = loop_transfer_bio(lo, bio, rbh);
bio_endio(rbh, rbh->bi_size, ret);
loop_put_buffer(bio);
}
}
/*
* worker thread that handles reads/writes to file backed loop devices,
* to avoid blocking in our make_request_fn. it also does loop decrypting
* on reads for block backed loop, as that is too heavy to do from
* b_end_io context where irqs may be disabled.
*/
static int loop_thread(void *data)
{
struct loop_device *lo = data;
struct bio *bio;
daemonize("loop%d", lo->lo_number);
/*
* loop can be used in an encrypted device,
* hence, it mustn't be stopped at all
* because it could be indirectly used during suspension
*/
current->flags |= PF_IOTHREAD;
set_user_nice(current, -20);
lo->lo_state = Lo_bound;
atomic_inc(&lo->lo_pending);
/*
* up sem, we are running
*/
up(&lo->lo_sem);
for (;;) {
down_interruptible(&lo->lo_bh_mutex);
/*
* could be upped because of tear-down, not because of
* pending work
*/
if (!atomic_read(&lo->lo_pending))
break;
bio = loop_get_bio(lo);
if (!bio) {
printk("loop: missing bio\n");
continue;
}
loop_handle_bio(lo, bio);
/*
* upped both for pending work and tear-down, lo_pending
* will hit zero then
*/
if (atomic_dec_and_test(&lo->lo_pending))
break;
}
up(&lo->lo_sem);
return 0;
}
static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
struct block_device *bdev, unsigned int arg)
{
struct file *file;
struct inode *inode;
struct block_device *lo_device = NULL;
struct address_space *mapping;
unsigned lo_blocksize;
int lo_flags = 0;
int error;
/* This is safe, since we have a reference from open(). */
__module_get(THIS_MODULE);
error = -EBUSY;
if (lo->lo_state != Lo_unbound)
goto out;
error = -EBADF;
file = fget(arg);
if (!file)
goto out;
mapping = file->f_mapping;
inode = mapping->host;
if (!(file->f_mode & FMODE_WRITE))
lo_flags |= LO_FLAGS_READ_ONLY;
error = -EINVAL;
if (S_ISBLK(inode->i_mode)) {
lo_device = I_BDEV(inode);
if (lo_device == bdev) {
error = -EBUSY;
goto out_putf;
}
lo_blocksize = block_size(lo_device);
if (bdev_read_only(lo_device))
lo_flags |= LO_FLAGS_READ_ONLY;
} else if (S_ISREG(inode->i_mode)) {
struct address_space_operations *aops = mapping->a_ops;
/*
* If we can't read - sorry. If we only can't write - well,
* it's going to be read-only.
*/
if (!inode->i_fop->sendfile)
goto out_putf;
if (!aops->prepare_write || !aops->commit_write)
lo_flags |= LO_FLAGS_READ_ONLY;
lo_blocksize = inode->i_blksize;
lo_flags |= LO_FLAGS_DO_BMAP;
} else
goto out_putf;
if (!(lo_file->f_mode & FMODE_WRITE))
lo_flags |= LO_FLAGS_READ_ONLY;
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
lo->lo_blocksize = lo_blocksize;
lo->lo_device = lo_device;
lo->lo_flags = lo_flags;
lo->lo_backing_file = file;
lo->transfer = NULL;
lo->ioctl = NULL;
lo->lo_sizelimit = 0;
if (figure_loop_size(lo)) {
error = -EFBIG;
goto out_putf;
}
lo->old_gfp_mask = mapping_gfp_mask(mapping);
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
lo->lo_bio = lo->lo_biotail = NULL;
/*
* set queue make_request_fn, and add limits based on lower level
* device
*/
blk_queue_make_request(lo->lo_queue, loop_make_request);
lo->lo_queue->queuedata = lo;
/*
* we remap to a block device, make sure we correctly stack limits
*/
if (S_ISBLK(inode->i_mode)) {
request_queue_t *q = bdev_get_queue(lo_device);
blk_queue_max_sectors(lo->lo_queue, q->max_sectors);
blk_queue_max_phys_segments(lo->lo_queue,q->max_phys_segments);
blk_queue_max_hw_segments(lo->lo_queue, q->max_hw_segments);
blk_queue_hardsect_size(lo->lo_queue, queue_hardsect_size(q));
blk_queue_max_segment_size(lo->lo_queue, q->max_segment_size);
blk_queue_segment_boundary(lo->lo_queue, q->seg_boundary_mask);
blk_queue_merge_bvec(lo->lo_queue, q->merge_bvec_fn);
}
set_blocksize(bdev, lo_blocksize);
kernel_thread(loop_thread, lo, CLONE_KERNEL);
down(&lo->lo_sem);
return 0;
out_putf:
fput(file);
out:
/* This is safe: open() is still holding a reference. */
module_put(THIS_MODULE);
return error;
}
static int
loop_release_xfer(struct loop_device *lo)
{
int err = 0;
struct loop_func_table *xfer = lo->lo_encryption;
if (xfer) {
if (xfer->release)
err = xfer->release(lo);
lo->transfer = NULL;
lo->lo_encryption = NULL;
module_put(xfer->owner);
}
return err;
}
static int
loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
const struct loop_info64 *i)
{
int err = 0;
if (xfer) {
struct module *owner = xfer->owner;
if (!try_module_get(owner))
return -EINVAL;
if (xfer->init)
err = xfer->init(lo, i);
if (err)
module_put(owner);
else
lo->lo_encryption = xfer;
}
return err;
}
static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
{
struct file *filp = lo->lo_backing_file;
int gfp = lo->old_gfp_mask;
if (lo->lo_state != Lo_bound)
return -ENXIO;
if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */
return -EBUSY;
if (filp == NULL)
return -EINVAL;
spin_lock_irq(&lo->lo_lock);
lo->lo_state = Lo_rundown;
if (atomic_dec_and_test(&lo->lo_pending))
up(&lo->lo_bh_mutex);
spin_unlock_irq(&lo->lo_lock);
down(&lo->lo_sem);
lo->lo_backing_file = NULL;
loop_release_xfer(lo);
lo->transfer = NULL;
lo->ioctl = NULL;
lo->lo_device = NULL;
lo->lo_encryption = NULL;
lo->lo_offset = 0;
lo->lo_sizelimit = 0;
lo->lo_encrypt_key_size = 0;
lo->lo_flags = 0;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
invalidate_bdev(bdev, 0);
set_capacity(disks[lo->lo_number], 0);
mapping_set_gfp_mask(filp->f_mapping, gfp);
lo->lo_state = Lo_unbound;
fput(filp);
/* This is safe: open() is still holding a reference. */
module_put(THIS_MODULE);
return 0;
}
static int
loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
{
int err;
struct loop_func_table *xfer;
if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
if (lo->lo_state != Lo_bound)
return -ENXIO;
if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
return -EINVAL;
err = loop_release_xfer(lo);
if (err)
return err;
if (info->lo_encrypt_type) {
unsigned int type = info->lo_encrypt_type;
if (type >= MAX_LO_CRYPT)
return -EINVAL;
xfer = xfer_funcs[type];
if (xfer == NULL)
return -EINVAL;
} else
xfer = NULL;
err = loop_init_xfer(lo, xfer, info);
if (err)
return err;
if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit) {
lo->lo_offset = info->lo_offset;
lo->lo_sizelimit = info->lo_sizelimit;
if (figure_loop_size(lo))
return -EFBIG;
}
memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
lo->lo_file_name[LO_NAME_SIZE-1] = 0;
lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
if (!xfer)
xfer = &none_funcs;
lo->transfer = xfer->transfer;
lo->ioctl = xfer->ioctl;
lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
lo->lo_init[0] = info->lo_init[0];
lo->lo_init[1] = info->lo_init[1];
if (info->lo_encrypt_key_size) {
memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
info->lo_encrypt_key_size);
lo->lo_key_owner = current->uid;
}
return 0;
}
static int
loop_get_status(struct loop_device *lo, struct loop_info64 *info)
{
struct file *file = lo->lo_backing_file;
struct kstat stat;
int error;
if (lo->lo_state != Lo_bound)
return -ENXIO;
error = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat);
if (error)
return error;
memset(info, 0, sizeof(*info));
info->lo_number = lo->lo_number;
info->lo_device = huge_encode_dev(stat.dev);
info->lo_inode = stat.ino;
info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev);
info->lo_offset = lo->lo_offset;
info->lo_sizelimit = lo->lo_sizelimit;
info->lo_flags = lo->lo_flags;
memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
info->lo_encrypt_type =
lo->lo_encryption ? lo->lo_encryption->number : 0;
if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
info->lo_encrypt_key_size = lo->lo_encrypt_key_size;
memcpy(info->lo_encrypt_key, lo->lo_encrypt_key,
lo->lo_encrypt_key_size);
}
return 0;
}
static void
loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64)
{
memset(info64, 0, sizeof(*info64));
info64->lo_number = info->lo_number;
info64->lo_device = info->lo_device;
info64->lo_inode = info->lo_inode;
info64->lo_rdevice = info->lo_rdevice;
info64->lo_offset = info->lo_offset;
info64->lo_sizelimit = 0;
info64->lo_encrypt_type = info->lo_encrypt_type;
info64->lo_encrypt_key_size = info->lo_encrypt_key_size;
info64->lo_flags = info->lo_flags;
info64->lo_init[0] = info->lo_init[0];
info64->lo_init[1] = info->lo_init[1];
if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
else
memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
}
static int
loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
{
memset(info, 0, sizeof(*info));
info->lo_number = info64->lo_number;
info->lo_device = info64->lo_device;
info->lo_inode = info64->lo_inode;
info->lo_rdevice = info64->lo_rdevice;
info->lo_offset = info64->lo_offset;
info->lo_encrypt_type = info64->lo_encrypt_type;
info->lo_encrypt_key_size = info64->lo_encrypt_key_size;
info->lo_flags = info64->lo_flags;
info->lo_init[0] = info64->lo_init[0];
info->lo_init[1] = info64->lo_init[1];
if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
else
memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
/* error in case values were truncated */
if (info->lo_device != info64->lo_device ||
info->lo_rdevice != info64->lo_rdevice ||
info->lo_inode != info64->lo_inode ||
info->lo_offset != info64->lo_offset)
return -EOVERFLOW;
return 0;
}
static int
loop_set_status_old(struct loop_device *lo, const struct loop_info *arg)
{
struct loop_info info;
struct loop_info64 info64;
if (copy_from_user(&info, arg, sizeof (struct loop_info)))
return -EFAULT;
loop_info64_from_old(&info, &info64);
return loop_set_status(lo, &info64);
}
static int
loop_set_status64(struct loop_device *lo, const struct loop_info64 *arg)
{
struct loop_info64 info64;
if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
return -EFAULT;
return loop_set_status(lo, &info64);
}
static int
loop_get_status_old(struct loop_device *lo, struct loop_info *arg) {
struct loop_info info;
struct loop_info64 info64;
int err = 0;
if (!arg)
err = -EINVAL;
if (!err)
err = loop_get_status(lo, &info64);
if (!err)
err = loop_info64_to_old(&info64, &info);
if (!err && copy_to_user(arg, &info, sizeof(info)))
err = -EFAULT;
return err;
}
static int
loop_get_status64(struct loop_device *lo, struct loop_info64 *arg) {
struct loop_info64 info64;
int err = 0;
if (!arg)
err = -EINVAL;
if (!err)
err = loop_get_status(lo, &info64);
if (!err && copy_to_user(arg, &info64, sizeof(info64)))
err = -EFAULT;
return err;
}
static int lo_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
int err;
down(&lo->lo_ctl_mutex);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, file, inode->i_bdev, arg);
break;
case LOOP_CLR_FD:
err = loop_clr_fd(lo, inode->i_bdev);
break;
case LOOP_SET_STATUS:
err = loop_set_status_old(lo, (struct loop_info *) arg);
break;
case LOOP_GET_STATUS:
err = loop_get_status_old(lo, (struct loop_info *) arg);
break;
case LOOP_SET_STATUS64:
err = loop_set_status64(lo, (struct loop_info64 *) arg);
break;
case LOOP_GET_STATUS64:
err = loop_get_status64(lo, (struct loop_info64 *) arg);
break;
default:
err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
}
up(&lo->lo_ctl_mutex);
return err;
}
static int lo_open(struct inode *inode, struct file *file)
{
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
down(&lo->lo_ctl_mutex);
lo->lo_refcnt++;
up(&lo->lo_ctl_mutex);
return 0;
}
static int lo_release(struct inode *inode, struct file *file)
{
struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
down(&lo->lo_ctl_mutex);
--lo->lo_refcnt;
up(&lo->lo_ctl_mutex);
return 0;
}
static struct block_device_operations lo_fops = {
.owner = THIS_MODULE,
.open = lo_open,
.release = lo_release,
.ioctl = lo_ioctl,
};
/*
* And now the modules code and kernel interface.
*/
MODULE_PARM(max_loop, "i");
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
int loop_register_transfer(struct loop_func_table *funcs)
{
unsigned int n = funcs->number;
if (n >= MAX_LO_CRYPT || xfer_funcs[n])
return -EINVAL;
xfer_funcs[n] = funcs;
return 0;
}
int loop_unregister_transfer(int number)
{
unsigned int n = number;
struct loop_device *lo;
struct loop_func_table *xfer;
if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
return -EINVAL;
xfer_funcs[n] = NULL;
for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
down(&lo->lo_ctl_mutex);
if (lo->lo_encryption == xfer)
loop_release_xfer(lo);
up(&lo->lo_ctl_mutex);
}
return 0;
}
EXPORT_SYMBOL(loop_register_transfer);
EXPORT_SYMBOL(loop_unregister_transfer);
int __init loop_init(void)
{
int i;
if (max_loop < 1 || max_loop > 256) {
printk(KERN_WARNING "loop: invalid max_loop (must be between"
" 1 and 256), using default (8)\n");
max_loop = 8;
}
if (register_blkdev(LOOP_MAJOR, "loop"))
return -EIO;
loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL);
if (!loop_dev)
goto out_mem1;
memset(loop_dev, 0, max_loop * sizeof(struct loop_device));
disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL);
if (!disks)
goto out_mem2;
for (i = 0; i < max_loop; i++) {
disks[i] = alloc_disk(1);
if (!disks[i])
goto out_mem3;
}
devfs_mk_dir("loop");
for (i = 0; i < max_loop; i++) {
struct loop_device *lo = &loop_dev[i];
struct gendisk *disk = disks[i];
memset(lo, 0, sizeof(*lo));
lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
if (!lo->lo_queue)
goto out_mem4;
disks[i]->queue = lo->lo_queue;
init_MUTEX(&lo->lo_ctl_mutex);
init_MUTEX_LOCKED(&lo->lo_sem);
init_MUTEX_LOCKED(&lo->lo_bh_mutex);
lo->lo_number = i;
spin_lock_init(&lo->lo_lock);
disk->major = LOOP_MAJOR;
disk->first_minor = i;
disk->fops = &lo_fops;
sprintf(disk->disk_name, "loop%d", i);
sprintf(disk->devfs_name, "loop/%d", i);
disk->private_data = lo;
disk->queue = lo->lo_queue;
add_disk(disk);
}
printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop);
return 0;
out_mem4:
while (i--)
blk_put_queue(loop_dev[i].lo_queue);
i = max_loop;
out_mem3:
while (i--)
put_disk(disks[i]);
kfree(disks);
out_mem2:
kfree(loop_dev);
out_mem1:
unregister_blkdev(LOOP_MAJOR, "loop");
printk(KERN_ERR "loop: ran out of memory\n");
return -ENOMEM;
}
void loop_exit(void)
{
int i;
for (i = 0; i < max_loop; i++) {
del_gendisk(disks[i]);
blk_put_queue(loop_dev[i].lo_queue);
put_disk(disks[i]);
}
devfs_remove("loop");
if (unregister_blkdev(LOOP_MAJOR, "loop"))
printk(KERN_WARNING "loop: cannot unregister blkdev\n");
kfree(disks);
kfree(loop_dev);
}
module_init(loop_init);
module_exit(loop_exit);
#ifndef MODULE
static int __init max_loop_setup(char *str)
{
max_loop = simple_strtol(str, NULL, 0);
return 1;
}
__setup("max_loop=", max_loop_setup);
#endif
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