| /* |
| * 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. Bolsø, <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 |
| * |
| * Support for falling back on the write file operation when the address space |
| * operations write_begin is not available on the backing filesystem. |
| * Anton Altaparmakov, 16 Feb 2005 |
| * |
| * Still To Fix: |
| * - Advisory locking is ignored here. |
| * - Should use an own CAP_* category instead of CAP_SYS_ADMIN |
| * |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.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/smp_lock.h> |
| #include <linux/swap.h> |
| #include <linux/slab.h> |
| #include <linux/loop.h> |
| #include <linux/compat.h> |
| #include <linux/suspend.h> |
| #include <linux/freezer.h> |
| #include <linux/writeback.h> |
| #include <linux/buffer_head.h> /* for invalidate_bdev() */ |
| #include <linux/completion.h> |
| #include <linux/highmem.h> |
| #include <linux/gfp.h> |
| #include <linux/kthread.h> |
| #include <linux/splice.h> |
| |
| #include <asm/uaccess.h> |
| |
| static LIST_HEAD(loop_devices); |
| static DEFINE_MUTEX(loop_devices_mutex); |
| |
| static int max_part; |
| static int part_shift; |
| |
| /* |
| * Transfer functions |
| */ |
| static int transfer_none(struct loop_device *lo, int cmd, |
| struct page *raw_page, unsigned raw_off, |
| struct page *loop_page, unsigned loop_off, |
| int size, sector_t real_block) |
| { |
| char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; |
| char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; |
| |
| if (cmd == READ) |
| memcpy(loop_buf, raw_buf, size); |
| else |
| memcpy(raw_buf, loop_buf, size); |
| |
| kunmap_atomic(raw_buf, KM_USER0); |
| kunmap_atomic(loop_buf, KM_USER1); |
| cond_resched(); |
| return 0; |
| } |
| |
| static int transfer_xor(struct loop_device *lo, int cmd, |
| struct page *raw_page, unsigned raw_off, |
| struct page *loop_page, unsigned loop_off, |
| int size, sector_t real_block) |
| { |
| char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off; |
| char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off; |
| 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]; |
| |
| kunmap_atomic(raw_buf, KM_USER0); |
| kunmap_atomic(loop_buf, KM_USER1); |
| cond_resched(); |
| return 0; |
| } |
| |
| static int xor_init(struct loop_device *lo, const struct loop_info64 *info) |
| { |
| if (unlikely(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 loff_t get_loop_size(struct loop_device *lo, struct file *file) |
| { |
| loff_t size, offset, loopsize; |
| |
| /* Compute loopsize in bytes */ |
| size = i_size_read(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. |
| */ |
| return loopsize >> 9; |
| } |
| |
| static int |
| figure_loop_size(struct loop_device *lo) |
| { |
| loff_t size = get_loop_size(lo, lo->lo_backing_file); |
| sector_t x = (sector_t)size; |
| |
| if (unlikely((loff_t)x != size)) |
| return -EFBIG; |
| |
| set_capacity(lo->lo_disk, x); |
| return 0; |
| } |
| |
| static inline int |
| lo_do_transfer(struct loop_device *lo, int cmd, |
| struct page *rpage, unsigned roffs, |
| struct page *lpage, unsigned loffs, |
| int size, sector_t rblock) |
| { |
| if (unlikely(!lo->transfer)) |
| return 0; |
| |
| return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock); |
| } |
| |
| /** |
| * do_lo_send_aops - helper for writing data to a loop device |
| * |
| * This is the fast version for backing filesystems which implement the address |
| * space operations write_begin and write_end. |
| */ |
| static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, |
| loff_t pos, struct page *unused) |
| { |
| struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */ |
| struct address_space *mapping = file->f_mapping; |
| pgoff_t index; |
| unsigned offset, bv_offs; |
| int len, ret; |
| |
| mutex_lock(&mapping->host->i_mutex); |
| index = pos >> PAGE_CACHE_SHIFT; |
| offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1); |
| bv_offs = bvec->bv_offset; |
| len = bvec->bv_len; |
| while (len > 0) { |
| sector_t IV; |
| unsigned size, copied; |
| int transfer_result; |
| struct page *page; |
| void *fsdata; |
| |
| IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); |
| size = PAGE_CACHE_SIZE - offset; |
| if (size > len) |
| size = len; |
| |
| ret = pagecache_write_begin(file, mapping, pos, size, 0, |
| &page, &fsdata); |
| if (ret) |
| goto fail; |
| |
| transfer_result = lo_do_transfer(lo, WRITE, page, offset, |
| bvec->bv_page, bv_offs, size, IV); |
| copied = size; |
| if (unlikely(transfer_result)) |
| copied = 0; |
| |
| ret = pagecache_write_end(file, mapping, pos, size, copied, |
| page, fsdata); |
| if (ret < 0 || ret != copied) |
| goto fail; |
| |
| if (unlikely(transfer_result)) |
| goto fail; |
| |
| bv_offs += copied; |
| len -= copied; |
| offset = 0; |
| index++; |
| pos += copied; |
| } |
| ret = 0; |
| out: |
| mutex_unlock(&mapping->host->i_mutex); |
| return ret; |
| fail: |
| ret = -1; |
| goto out; |
| } |
| |
| /** |
| * __do_lo_send_write - helper for writing data to a loop device |
| * |
| * This helper just factors out common code between do_lo_send_direct_write() |
| * and do_lo_send_write(). |
| */ |
| static int __do_lo_send_write(struct file *file, |
| u8 *buf, const int len, loff_t pos) |
| { |
| ssize_t bw; |
| mm_segment_t old_fs = get_fs(); |
| |
| set_fs(get_ds()); |
| bw = file->f_op->write(file, buf, len, &pos); |
| set_fs(old_fs); |
| if (likely(bw == len)) |
| return 0; |
| printk(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n", |
| (unsigned long long)pos, len); |
| if (bw >= 0) |
| bw = -EIO; |
| return bw; |
| } |
| |
| /** |
| * do_lo_send_direct_write - helper for writing data to a loop device |
| * |
| * This is the fast, non-transforming version for backing filesystems which do |
| * not implement the address space operations write_begin and write_end. |
| * It uses the write file operation which should be present on all writeable |
| * filesystems. |
| */ |
| static int do_lo_send_direct_write(struct loop_device *lo, |
| struct bio_vec *bvec, loff_t pos, struct page *page) |
| { |
| ssize_t bw = __do_lo_send_write(lo->lo_backing_file, |
| kmap(bvec->bv_page) + bvec->bv_offset, |
| bvec->bv_len, pos); |
| kunmap(bvec->bv_page); |
| cond_resched(); |
| return bw; |
| } |
| |
| /** |
| * do_lo_send_write - helper for writing data to a loop device |
| * |
| * This is the slow, transforming version for filesystems which do not |
| * implement the address space operations write_begin and write_end. It |
| * uses the write file operation which should be present on all writeable |
| * filesystems. |
| * |
| * Using fops->write is slower than using aops->{prepare,commit}_write in the |
| * transforming case because we need to double buffer the data as we cannot do |
| * the transformations in place as we do not have direct access to the |
| * destination pages of the backing file. |
| */ |
| static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec, |
| loff_t pos, struct page *page) |
| { |
| int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page, |
| bvec->bv_offset, bvec->bv_len, pos >> 9); |
| if (likely(!ret)) |
| return __do_lo_send_write(lo->lo_backing_file, |
| page_address(page), bvec->bv_len, |
| pos); |
| printk(KERN_ERR "loop: Transfer error at byte offset %llu, " |
| "length %i.\n", (unsigned long long)pos, bvec->bv_len); |
| if (ret > 0) |
| ret = -EIO; |
| return ret; |
| } |
| |
| static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos) |
| { |
| int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t, |
| struct page *page); |
| struct bio_vec *bvec; |
| struct page *page = NULL; |
| int i, ret = 0; |
| |
| do_lo_send = do_lo_send_aops; |
| if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) { |
| do_lo_send = do_lo_send_direct_write; |
| if (lo->transfer != transfer_none) { |
| page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); |
| if (unlikely(!page)) |
| goto fail; |
| kmap(page); |
| do_lo_send = do_lo_send_write; |
| } |
| } |
| bio_for_each_segment(bvec, bio, i) { |
| ret = do_lo_send(lo, bvec, pos, page); |
| if (ret < 0) |
| break; |
| pos += bvec->bv_len; |
| } |
| if (page) { |
| kunmap(page); |
| __free_page(page); |
| } |
| out: |
| return ret; |
| fail: |
| printk(KERN_ERR "loop: Failed to allocate temporary page for write.\n"); |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| struct lo_read_data { |
| struct loop_device *lo; |
| struct page *page; |
| unsigned offset; |
| int bsize; |
| }; |
| |
| static int |
| lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, |
| struct splice_desc *sd) |
| { |
| struct lo_read_data *p = sd->u.data; |
| struct loop_device *lo = p->lo; |
| struct page *page = buf->page; |
| sector_t IV; |
| int size, ret; |
| |
| ret = buf->ops->confirm(pipe, buf); |
| if (unlikely(ret)) |
| return ret; |
| |
| IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) + |
| (buf->offset >> 9); |
| size = sd->len; |
| if (size > p->bsize) |
| size = p->bsize; |
| |
| if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) { |
| printk(KERN_ERR "loop: transfer error block %ld\n", |
| page->index); |
| size = -EINVAL; |
| } |
| |
| flush_dcache_page(p->page); |
| |
| if (size > 0) |
| p->offset += size; |
| |
| return size; |
| } |
| |
| static int |
| lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) |
| { |
| return __splice_from_pipe(pipe, sd, lo_splice_actor); |
| } |
| |
| static int |
| do_lo_receive(struct loop_device *lo, |
| struct bio_vec *bvec, int bsize, loff_t pos) |
| { |
| struct lo_read_data cookie; |
| struct splice_desc sd; |
| struct file *file; |
| long retval; |
| |
| cookie.lo = lo; |
| cookie.page = bvec->bv_page; |
| cookie.offset = bvec->bv_offset; |
| cookie.bsize = bsize; |
| |
| sd.len = 0; |
| sd.total_len = bvec->bv_len; |
| sd.flags = 0; |
| sd.pos = pos; |
| sd.u.data = &cookie; |
| |
| file = lo->lo_backing_file; |
| retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor); |
| |
| if (retval < 0) |
| return retval; |
| |
| return 0; |
| } |
| |
| static int |
| lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos) |
| { |
| struct bio_vec *bvec; |
| int i, ret = 0; |
| |
| bio_for_each_segment(bvec, bio, i) { |
| 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) { |
| int barrier = bio_barrier(bio); |
| struct file *file = lo->lo_backing_file; |
| |
| if (barrier) { |
| if (unlikely(!file->f_op->fsync)) { |
| ret = -EOPNOTSUPP; |
| goto out; |
| } |
| |
| ret = vfs_fsync(file, file->f_path.dentry, 0); |
| if (unlikely(ret)) { |
| ret = -EIO; |
| goto out; |
| } |
| } |
| |
| ret = lo_send(lo, bio, pos); |
| |
| if (barrier && !ret) { |
| ret = vfs_fsync(file, file->f_path.dentry, 0); |
| if (unlikely(ret)) |
| ret = -EIO; |
| } |
| } else |
| ret = lo_receive(lo, bio, lo->lo_blocksize, pos); |
| |
| out: |
| return ret; |
| } |
| |
| /* |
| * Add bio to back of pending list |
| */ |
| static void loop_add_bio(struct loop_device *lo, struct bio *bio) |
| { |
| bio_list_add(&lo->lo_bio_list, bio); |
| } |
| |
| /* |
| * Grab first pending buffer |
| */ |
| static struct bio *loop_get_bio(struct loop_device *lo) |
| { |
| return bio_list_pop(&lo->lo_bio_list); |
| } |
| |
| static int loop_make_request(struct request_queue *q, struct bio *old_bio) |
| { |
| struct loop_device *lo = q->queuedata; |
| int rw = bio_rw(old_bio); |
| |
| if (rw == READA) |
| rw = READ; |
| |
| BUG_ON(!lo || (rw != READ && rw != WRITE)); |
| |
| spin_lock_irq(&lo->lo_lock); |
| if (lo->lo_state != Lo_bound) |
| goto out; |
| if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY))) |
| goto out; |
| loop_add_bio(lo, old_bio); |
| wake_up(&lo->lo_event); |
| spin_unlock_irq(&lo->lo_lock); |
| return 0; |
| |
| out: |
| spin_unlock_irq(&lo->lo_lock); |
| bio_io_error(old_bio); |
| return 0; |
| } |
| |
| /* |
| * kick off io on the underlying address space |
| */ |
| static void loop_unplug(struct request_queue *q) |
| { |
| struct loop_device *lo = q->queuedata; |
| |
| queue_flag_clear_unlocked(QUEUE_FLAG_PLUGGED, q); |
| blk_run_address_space(lo->lo_backing_file->f_mapping); |
| } |
| |
| struct switch_request { |
| struct file *file; |
| struct completion wait; |
| }; |
| |
| static void do_loop_switch(struct loop_device *, struct switch_request *); |
| |
| static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio) |
| { |
| if (unlikely(!bio->bi_bdev)) { |
| do_loop_switch(lo, bio->bi_private); |
| bio_put(bio); |
| } else { |
| int ret = do_bio_filebacked(lo, bio); |
| bio_endio(bio, ret); |
| } |
| } |
| |
| /* |
| * 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. |
| * |
| * Loop explanation: loop_clr_fd() sets lo_state to Lo_rundown before |
| * calling kthread_stop(). Therefore once kthread_should_stop() is |
| * true, make_request will not place any more requests. Therefore |
| * once kthread_should_stop() is true and lo_bio is NULL, we are |
| * done with the loop. |
| */ |
| static int loop_thread(void *data) |
| { |
| struct loop_device *lo = data; |
| struct bio *bio; |
| |
| set_user_nice(current, -20); |
| |
| while (!kthread_should_stop() || !bio_list_empty(&lo->lo_bio_list)) { |
| |
| wait_event_interruptible(lo->lo_event, |
| !bio_list_empty(&lo->lo_bio_list) || |
| kthread_should_stop()); |
| |
| if (bio_list_empty(&lo->lo_bio_list)) |
| continue; |
| spin_lock_irq(&lo->lo_lock); |
| bio = loop_get_bio(lo); |
| spin_unlock_irq(&lo->lo_lock); |
| |
| BUG_ON(!bio); |
| loop_handle_bio(lo, bio); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * loop_switch performs the hard work of switching a backing store. |
| * First it needs to flush existing IO, it does this by sending a magic |
| * BIO down the pipe. The completion of this BIO does the actual switch. |
| */ |
| static int loop_switch(struct loop_device *lo, struct file *file) |
| { |
| struct switch_request w; |
| struct bio *bio = bio_alloc(GFP_KERNEL, 0); |
| if (!bio) |
| return -ENOMEM; |
| init_completion(&w.wait); |
| w.file = file; |
| bio->bi_private = &w; |
| bio->bi_bdev = NULL; |
| loop_make_request(lo->lo_queue, bio); |
| wait_for_completion(&w.wait); |
| return 0; |
| } |
| |
| /* |
| * Helper to flush the IOs in loop, but keeping loop thread running |
| */ |
| static int loop_flush(struct loop_device *lo) |
| { |
| /* loop not yet configured, no running thread, nothing to flush */ |
| if (!lo->lo_thread) |
| return 0; |
| |
| return loop_switch(lo, NULL); |
| } |
| |
| /* |
| * Do the actual switch; called from the BIO completion routine |
| */ |
| static void do_loop_switch(struct loop_device *lo, struct switch_request *p) |
| { |
| struct file *file = p->file; |
| struct file *old_file = lo->lo_backing_file; |
| struct address_space *mapping; |
| |
| /* if no new file, only flush of queued bios requested */ |
| if (!file) |
| goto out; |
| |
| mapping = file->f_mapping; |
| mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask); |
| lo->lo_backing_file = file; |
| lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ? |
| mapping->host->i_bdev->bd_block_size : PAGE_SIZE; |
| lo->old_gfp_mask = mapping_gfp_mask(mapping); |
| mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
| out: |
| complete(&p->wait); |
| } |
| |
| |
| /* |
| * loop_change_fd switched the backing store of a loopback device to |
| * a new file. This is useful for operating system installers to free up |
| * the original file and in High Availability environments to switch to |
| * an alternative location for the content in case of server meltdown. |
| * This can only work if the loop device is used read-only, and if the |
| * new backing store is the same size and type as the old backing store. |
| */ |
| static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, |
| unsigned int arg) |
| { |
| struct file *file, *old_file; |
| struct inode *inode; |
| int error; |
| |
| error = -ENXIO; |
| if (lo->lo_state != Lo_bound) |
| goto out; |
| |
| /* the loop device has to be read-only */ |
| error = -EINVAL; |
| if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) |
| goto out; |
| |
| error = -EBADF; |
| file = fget(arg); |
| if (!file) |
| goto out; |
| |
| inode = file->f_mapping->host; |
| old_file = lo->lo_backing_file; |
| |
| error = -EINVAL; |
| |
| if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
| goto out_putf; |
| |
| /* new backing store needs to support loop (eg splice_read) */ |
| if (!inode->i_fop->splice_read) |
| goto out_putf; |
| |
| /* size of the new backing store needs to be the same */ |
| if (get_loop_size(lo, file) != get_loop_size(lo, old_file)) |
| goto out_putf; |
| |
| /* and ... switch */ |
| error = loop_switch(lo, file); |
| if (error) |
| goto out_putf; |
| |
| fput(old_file); |
| if (max_part > 0) |
| ioctl_by_bdev(bdev, BLKRRPART, 0); |
| return 0; |
| |
| out_putf: |
| fput(file); |
| out: |
| return error; |
| } |
| |
| static inline int is_loop_device(struct file *file) |
| { |
| struct inode *i = file->f_mapping->host; |
| |
| return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; |
| } |
| |
| static int loop_set_fd(struct loop_device *lo, fmode_t mode, |
| struct block_device *bdev, unsigned int arg) |
| { |
| struct file *file, *f; |
| struct inode *inode; |
| struct address_space *mapping; |
| unsigned lo_blocksize; |
| int lo_flags = 0; |
| int error; |
| loff_t size; |
| |
| /* This is safe, since we have a reference from open(). */ |
| __module_get(THIS_MODULE); |
| |
| error = -EBADF; |
| file = fget(arg); |
| if (!file) |
| goto out; |
| |
| error = -EBUSY; |
| if (lo->lo_state != Lo_unbound) |
| goto out_putf; |
| |
| /* Avoid recursion */ |
| f = file; |
| while (is_loop_device(f)) { |
| struct loop_device *l; |
| |
| if (f->f_mapping->host->i_bdev == bdev) |
| goto out_putf; |
| |
| l = f->f_mapping->host->i_bdev->bd_disk->private_data; |
| if (l->lo_state == Lo_unbound) { |
| error = -EINVAL; |
| goto out_putf; |
| } |
| f = l->lo_backing_file; |
| } |
| |
| mapping = file->f_mapping; |
| inode = mapping->host; |
| |
| if (!(file->f_mode & FMODE_WRITE)) |
| lo_flags |= LO_FLAGS_READ_ONLY; |
| |
| error = -EINVAL; |
| if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) { |
| const 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 (!file->f_op->splice_read) |
| goto out_putf; |
| if (aops->write_begin) |
| lo_flags |= LO_FLAGS_USE_AOPS; |
| if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write) |
| lo_flags |= LO_FLAGS_READ_ONLY; |
| |
| lo_blocksize = S_ISBLK(inode->i_mode) ? |
| inode->i_bdev->bd_block_size : PAGE_SIZE; |
| |
| error = 0; |
| } else { |
| goto out_putf; |
| } |
| |
| size = get_loop_size(lo, file); |
| |
| if ((loff_t)(sector_t)size != size) { |
| error = -EFBIG; |
| goto out_putf; |
| } |
| |
| if (!(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 = bdev; |
| lo->lo_flags = lo_flags; |
| lo->lo_backing_file = file; |
| lo->transfer = transfer_none; |
| lo->ioctl = NULL; |
| lo->lo_sizelimit = 0; |
| lo->old_gfp_mask = mapping_gfp_mask(mapping); |
| mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
| |
| bio_list_init(&lo->lo_bio_list); |
| |
| /* |
| * 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; |
| lo->lo_queue->unplug_fn = loop_unplug; |
| |
| if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
| blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN, NULL); |
| |
| set_capacity(lo->lo_disk, size); |
| bd_set_size(bdev, size << 9); |
| |
| set_blocksize(bdev, lo_blocksize); |
| |
| lo->lo_thread = kthread_create(loop_thread, lo, "loop%d", |
| lo->lo_number); |
| if (IS_ERR(lo->lo_thread)) { |
| error = PTR_ERR(lo->lo_thread); |
| goto out_clr; |
| } |
| lo->lo_state = Lo_bound; |
| wake_up_process(lo->lo_thread); |
| if (max_part > 0) |
| ioctl_by_bdev(bdev, BLKRRPART, 0); |
| return 0; |
| |
| out_clr: |
| lo->lo_thread = NULL; |
| lo->lo_device = NULL; |
| lo->lo_backing_file = NULL; |
| lo->lo_flags = 0; |
| set_capacity(lo->lo_disk, 0); |
| invalidate_bdev(bdev); |
| bd_set_size(bdev, 0); |
| mapping_set_gfp_mask(mapping, lo->old_gfp_mask); |
| lo->lo_state = Lo_unbound; |
| 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; |
| gfp_t 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; |
| spin_unlock_irq(&lo->lo_lock); |
| |
| kthread_stop(lo->lo_thread); |
| |
| lo->lo_queue->unplug_fn = NULL; |
| 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; |
| lo->lo_thread = NULL; |
| 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); |
| if (bdev) |
| invalidate_bdev(bdev); |
| set_capacity(lo->lo_disk, 0); |
| if (bdev) |
| bd_set_size(bdev, 0); |
| mapping_set_gfp_mask(filp->f_mapping, gfp); |
| lo->lo_state = Lo_unbound; |
| /* This is safe: open() is still holding a reference. */ |
| module_put(THIS_MODULE); |
| if (max_part > 0) |
| ioctl_by_bdev(bdev, BLKRRPART, 0); |
| mutex_unlock(&lo->lo_ctl_mutex); |
| /* |
| * Need not hold lo_ctl_mutex to fput backing file. |
| * Calling fput holding lo_ctl_mutex triggers a circular |
| * lock dependency possibility warning as fput can take |
| * bd_mutex which is usually taken before lo_ctl_mutex. |
| */ |
| fput(filp); |
| return 0; |
| } |
| |
| static int |
| loop_set_status(struct loop_device *lo, const struct loop_info64 *info) |
| { |
| int err; |
| struct loop_func_table *xfer; |
| uid_t uid = current_uid(); |
| |
| if (lo->lo_encrypt_key_size && |
| lo->lo_key_owner != 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; |
| |
| if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) != |
| (info->lo_flags & LO_FLAGS_AUTOCLEAR)) |
| lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; |
| |
| 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 = 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_path.mnt, file->f_path.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 __user *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 __user *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 __user *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 __user *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 loop_set_capacity(struct loop_device *lo, struct block_device *bdev) |
| { |
| int err; |
| sector_t sec; |
| loff_t sz; |
| |
| err = -ENXIO; |
| if (unlikely(lo->lo_state != Lo_bound)) |
| goto out; |
| err = figure_loop_size(lo); |
| if (unlikely(err)) |
| goto out; |
| sec = get_capacity(lo->lo_disk); |
| /* the width of sector_t may be narrow for bit-shift */ |
| sz = sec; |
| sz <<= 9; |
| mutex_lock(&bdev->bd_mutex); |
| bd_set_size(bdev, sz); |
| mutex_unlock(&bdev->bd_mutex); |
| |
| out: |
| return err; |
| } |
| |
| static int lo_ioctl(struct block_device *bdev, fmode_t mode, |
| unsigned int cmd, unsigned long arg) |
| { |
| struct loop_device *lo = bdev->bd_disk->private_data; |
| int err; |
| |
| mutex_lock_nested(&lo->lo_ctl_mutex, 1); |
| switch (cmd) { |
| case LOOP_SET_FD: |
| err = loop_set_fd(lo, mode, bdev, arg); |
| break; |
| case LOOP_CHANGE_FD: |
| err = loop_change_fd(lo, bdev, arg); |
| break; |
| case LOOP_CLR_FD: |
| /* loop_clr_fd would have unlocked lo_ctl_mutex on success */ |
| err = loop_clr_fd(lo, bdev); |
| if (!err) |
| goto out_unlocked; |
| break; |
| case LOOP_SET_STATUS: |
| err = loop_set_status_old(lo, (struct loop_info __user *) arg); |
| break; |
| case LOOP_GET_STATUS: |
| err = loop_get_status_old(lo, (struct loop_info __user *) arg); |
| break; |
| case LOOP_SET_STATUS64: |
| err = loop_set_status64(lo, (struct loop_info64 __user *) arg); |
| break; |
| case LOOP_GET_STATUS64: |
| err = loop_get_status64(lo, (struct loop_info64 __user *) arg); |
| break; |
| case LOOP_SET_CAPACITY: |
| err = -EPERM; |
| if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) |
| err = loop_set_capacity(lo, bdev); |
| break; |
| default: |
| err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; |
| } |
| mutex_unlock(&lo->lo_ctl_mutex); |
| |
| out_unlocked: |
| return err; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| struct compat_loop_info { |
| compat_int_t lo_number; /* ioctl r/o */ |
| compat_dev_t lo_device; /* ioctl r/o */ |
| compat_ulong_t lo_inode; /* ioctl r/o */ |
| compat_dev_t lo_rdevice; /* ioctl r/o */ |
| compat_int_t lo_offset; |
| compat_int_t lo_encrypt_type; |
| compat_int_t lo_encrypt_key_size; /* ioctl w/o */ |
| compat_int_t lo_flags; /* ioctl r/o */ |
| char lo_name[LO_NAME_SIZE]; |
| unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */ |
| compat_ulong_t lo_init[2]; |
| char reserved[4]; |
| }; |
| |
| /* |
| * Transfer 32-bit compatibility structure in userspace to 64-bit loop info |
| * - noinlined to reduce stack space usage in main part of driver |
| */ |
| static noinline int |
| loop_info64_from_compat(const struct compat_loop_info __user *arg, |
| struct loop_info64 *info64) |
| { |
| struct compat_loop_info info; |
| |
| if (copy_from_user(&info, arg, sizeof(info))) |
| return -EFAULT; |
| |
| 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); |
| return 0; |
| } |
| |
| /* |
| * Transfer 64-bit loop info to 32-bit compatibility structure in userspace |
| * - noinlined to reduce stack space usage in main part of driver |
| */ |
| static noinline int |
| loop_info64_to_compat(const struct loop_info64 *info64, |
| struct compat_loop_info __user *arg) |
| { |
| struct compat_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 || |
| info.lo_init[0] != info64->lo_init[0] || |
| info.lo_init[1] != info64->lo_init[1]) |
| return -EOVERFLOW; |
| |
| if (copy_to_user(arg, &info, sizeof(info))) |
| return -EFAULT; |
| return 0; |
| } |
| |
| static int |
| loop_set_status_compat(struct loop_device *lo, |
| const struct compat_loop_info __user *arg) |
| { |
| struct loop_info64 info64; |
| int ret; |
| |
| ret = loop_info64_from_compat(arg, &info64); |
| if (ret < 0) |
| return ret; |
| return loop_set_status(lo, &info64); |
| } |
| |
| static int |
| loop_get_status_compat(struct loop_device *lo, |
| struct compat_loop_info __user *arg) |
| { |
| 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_compat(&info64, arg); |
| return err; |
| } |
| |
| static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, |
| unsigned int cmd, unsigned long arg) |
| { |
| struct loop_device *lo = bdev->bd_disk->private_data; |
| int err; |
| |
| switch(cmd) { |
| case LOOP_SET_STATUS: |
| mutex_lock(&lo->lo_ctl_mutex); |
| err = loop_set_status_compat( |
| lo, (const struct compat_loop_info __user *) arg); |
| mutex_unlock(&lo->lo_ctl_mutex); |
| break; |
| case LOOP_GET_STATUS: |
| mutex_lock(&lo->lo_ctl_mutex); |
| err = loop_get_status_compat( |
| lo, (struct compat_loop_info __user *) arg); |
| mutex_unlock(&lo->lo_ctl_mutex); |
| break; |
| case LOOP_SET_CAPACITY: |
| case LOOP_CLR_FD: |
| case LOOP_GET_STATUS64: |
| case LOOP_SET_STATUS64: |
| arg = (unsigned long) compat_ptr(arg); |
| case LOOP_SET_FD: |
| case LOOP_CHANGE_FD: |
| err = lo_ioctl(bdev, mode, cmd, arg); |
| break; |
| default: |
| err = -ENOIOCTLCMD; |
| break; |
| } |
| return err; |
| } |
| #endif |
| |
| static int lo_open(struct block_device *bdev, fmode_t mode) |
| { |
| struct loop_device *lo = bdev->bd_disk->private_data; |
| |
| mutex_lock(&lo->lo_ctl_mutex); |
| lo->lo_refcnt++; |
| mutex_unlock(&lo->lo_ctl_mutex); |
| |
| return 0; |
| } |
| |
| static int lo_release(struct gendisk *disk, fmode_t mode) |
| { |
| struct loop_device *lo = disk->private_data; |
| int err; |
| |
| mutex_lock(&lo->lo_ctl_mutex); |
| |
| if (--lo->lo_refcnt) |
| goto out; |
| |
| if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { |
| /* |
| * In autoclear mode, stop the loop thread |
| * and remove configuration after last close. |
| */ |
| err = loop_clr_fd(lo, NULL); |
| if (!err) |
| goto out_unlocked; |
| } else { |
| /* |
| * Otherwise keep thread (if running) and config, |
| * but flush possible ongoing bios in thread. |
| */ |
| loop_flush(lo); |
| } |
| |
| out: |
| mutex_unlock(&lo->lo_ctl_mutex); |
| out_unlocked: |
| return 0; |
| } |
| |
| static struct block_device_operations lo_fops = { |
| .owner = THIS_MODULE, |
| .open = lo_open, |
| .release = lo_release, |
| .ioctl = lo_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = lo_compat_ioctl, |
| #endif |
| }; |
| |
| /* |
| * And now the modules code and kernel interface. |
| */ |
| static int max_loop; |
| module_param(max_loop, int, 0); |
| MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
| module_param(max_part, int, 0); |
| MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
| 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; |
| |
| list_for_each_entry(lo, &loop_devices, lo_list) { |
| mutex_lock(&lo->lo_ctl_mutex); |
| |
| if (lo->lo_encryption == xfer) |
| loop_release_xfer(lo); |
| |
| mutex_unlock(&lo->lo_ctl_mutex); |
| } |
| |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(loop_register_transfer); |
| EXPORT_SYMBOL(loop_unregister_transfer); |
| |
| static struct loop_device *loop_alloc(int i) |
| { |
| struct loop_device *lo; |
| struct gendisk *disk; |
| |
| lo = kzalloc(sizeof(*lo), GFP_KERNEL); |
| if (!lo) |
| goto out; |
| |
| lo->lo_queue = blk_alloc_queue(GFP_KERNEL); |
| if (!lo->lo_queue) |
| goto out_free_dev; |
| |
| disk = lo->lo_disk = alloc_disk(1 << part_shift); |
| if (!disk) |
| goto out_free_queue; |
| |
| mutex_init(&lo->lo_ctl_mutex); |
| lo->lo_number = i; |
| lo->lo_thread = NULL; |
| init_waitqueue_head(&lo->lo_event); |
| spin_lock_init(&lo->lo_lock); |
| disk->major = LOOP_MAJOR; |
| disk->first_minor = i << part_shift; |
| disk->fops = &lo_fops; |
| disk->private_data = lo; |
| disk->queue = lo->lo_queue; |
| sprintf(disk->disk_name, "loop%d", i); |
| return lo; |
| |
| out_free_queue: |
| blk_cleanup_queue(lo->lo_queue); |
| out_free_dev: |
| kfree(lo); |
| out: |
| return NULL; |
| } |
| |
| static void loop_free(struct loop_device *lo) |
| { |
| blk_cleanup_queue(lo->lo_queue); |
| put_disk(lo->lo_disk); |
| list_del(&lo->lo_list); |
| kfree(lo); |
| } |
| |
| static struct loop_device *loop_init_one(int i) |
| { |
| struct loop_device *lo; |
| |
| list_for_each_entry(lo, &loop_devices, lo_list) { |
| if (lo->lo_number == i) |
| return lo; |
| } |
| |
| lo = loop_alloc(i); |
| if (lo) { |
| add_disk(lo->lo_disk); |
| list_add_tail(&lo->lo_list, &loop_devices); |
| } |
| return lo; |
| } |
| |
| static void loop_del_one(struct loop_device *lo) |
| { |
| del_gendisk(lo->lo_disk); |
| loop_free(lo); |
| } |
| |
| static struct kobject *loop_probe(dev_t dev, int *part, void *data) |
| { |
| struct loop_device *lo; |
| struct kobject *kobj; |
| |
| mutex_lock(&loop_devices_mutex); |
| lo = loop_init_one(dev & MINORMASK); |
| kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM); |
| mutex_unlock(&loop_devices_mutex); |
| |
| *part = 0; |
| return kobj; |
| } |
| |
| static int __init loop_init(void) |
| { |
| int i, nr; |
| unsigned long range; |
| struct loop_device *lo, *next; |
| |
| /* |
| * loop module now has a feature to instantiate underlying device |
| * structure on-demand, provided that there is an access dev node. |
| * However, this will not work well with user space tool that doesn't |
| * know about such "feature". In order to not break any existing |
| * tool, we do the following: |
| * |
| * (1) if max_loop is specified, create that many upfront, and this |
| * also becomes a hard limit. |
| * (2) if max_loop is not specified, create 8 loop device on module |
| * load, user can further extend loop device by create dev node |
| * themselves and have kernel automatically instantiate actual |
| * device on-demand. |
| */ |
| |
| part_shift = 0; |
| if (max_part > 0) |
| part_shift = fls(max_part); |
| |
| if (max_loop > 1UL << (MINORBITS - part_shift)) |
| return -EINVAL; |
| |
| if (max_loop) { |
| nr = max_loop; |
| range = max_loop; |
| } else { |
| nr = 8; |
| range = 1UL << (MINORBITS - part_shift); |
| } |
| |
| if (register_blkdev(LOOP_MAJOR, "loop")) |
| return -EIO; |
| |
| for (i = 0; i < nr; i++) { |
| lo = loop_alloc(i); |
| if (!lo) |
| goto Enomem; |
| list_add_tail(&lo->lo_list, &loop_devices); |
| } |
| |
| /* point of no return */ |
| |
| list_for_each_entry(lo, &loop_devices, lo_list) |
| add_disk(lo->lo_disk); |
| |
| blk_register_region(MKDEV(LOOP_MAJOR, 0), range, |
| THIS_MODULE, loop_probe, NULL, NULL); |
| |
| printk(KERN_INFO "loop: module loaded\n"); |
| return 0; |
| |
| Enomem: |
| printk(KERN_INFO "loop: out of memory\n"); |
| |
| list_for_each_entry_safe(lo, next, &loop_devices, lo_list) |
| loop_free(lo); |
| |
| unregister_blkdev(LOOP_MAJOR, "loop"); |
| return -ENOMEM; |
| } |
| |
| static void __exit loop_exit(void) |
| { |
| unsigned long range; |
| struct loop_device *lo, *next; |
| |
| range = max_loop ? max_loop : 1UL << (MINORBITS - part_shift); |
| |
| list_for_each_entry_safe(lo, next, &loop_devices, lo_list) |
| loop_del_one(lo); |
| |
| blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range); |
| unregister_blkdev(LOOP_MAJOR, "loop"); |
| } |
| |
| 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 |