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https://mirrors.bfsu.edu.cn/git/linux.git
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2fe5de9ce7
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1930 lines
47 KiB
C
1930 lines
47 KiB
C
/*
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* linux/drivers/block/loop.c
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*
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* Written by Theodore Ts'o, 3/29/93
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*
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* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
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* permitted under the GNU General Public License.
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*
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* DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
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* more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
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*
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* Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
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* Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
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*
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* Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
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*
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* Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
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*
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* Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
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*
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* Loadable modules and other fixes by AK, 1998
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*
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* Make real block number available to downstream transfer functions, enables
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* CBC (and relatives) mode encryption requiring unique IVs per data block.
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* Reed H. Petty, rhp@draper.net
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*
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* Maximum number of loop devices now dynamic via max_loop module parameter.
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* Russell Kroll <rkroll@exploits.org> 19990701
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*
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* Maximum number of loop devices when compiled-in now selectable by passing
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* max_loop=<1-255> to the kernel on boot.
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* Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999
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*
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* Completely rewrite request handling to be make_request_fn style and
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* non blocking, pushing work to a helper thread. Lots of fixes from
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* Al Viro too.
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* Jens Axboe <axboe@suse.de>, Nov 2000
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*
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* Support up to 256 loop devices
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* Heinz Mauelshagen <mge@sistina.com>, Feb 2002
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*
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* Support for falling back on the write file operation when the address space
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* operations write_begin is not available on the backing filesystem.
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* Anton Altaparmakov, 16 Feb 2005
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*
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* Still To Fix:
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* - Advisory locking is ignored here.
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* - Should use an own CAP_* category instead of CAP_SYS_ADMIN
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*
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/major.h>
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#include <linux/wait.h>
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#include <linux/blkdev.h>
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#include <linux/blkpg.h>
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#include <linux/init.h>
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#include <linux/swap.h>
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#include <linux/slab.h>
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#include <linux/compat.h>
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#include <linux/suspend.h>
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#include <linux/freezer.h>
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#include <linux/mutex.h>
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#include <linux/writeback.h>
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#include <linux/completion.h>
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#include <linux/highmem.h>
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#include <linux/kthread.h>
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#include <linux/splice.h>
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#include <linux/sysfs.h>
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#include <linux/miscdevice.h>
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#include <linux/falloc.h>
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#include "loop.h"
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#include <asm/uaccess.h>
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static DEFINE_IDR(loop_index_idr);
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static DEFINE_MUTEX(loop_index_mutex);
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static int max_part;
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static int part_shift;
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/*
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* Transfer functions
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*/
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static int transfer_none(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block)
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{
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char *raw_buf = kmap_atomic(raw_page) + raw_off;
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char *loop_buf = kmap_atomic(loop_page) + loop_off;
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if (cmd == READ)
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memcpy(loop_buf, raw_buf, size);
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else
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memcpy(raw_buf, loop_buf, size);
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kunmap_atomic(loop_buf);
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kunmap_atomic(raw_buf);
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cond_resched();
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return 0;
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}
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static int transfer_xor(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block)
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{
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char *raw_buf = kmap_atomic(raw_page) + raw_off;
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char *loop_buf = kmap_atomic(loop_page) + loop_off;
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char *in, *out, *key;
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int i, keysize;
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if (cmd == READ) {
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in = raw_buf;
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out = loop_buf;
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} else {
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in = loop_buf;
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out = raw_buf;
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}
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key = lo->lo_encrypt_key;
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keysize = lo->lo_encrypt_key_size;
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for (i = 0; i < size; i++)
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*out++ = *in++ ^ key[(i & 511) % keysize];
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kunmap_atomic(loop_buf);
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kunmap_atomic(raw_buf);
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cond_resched();
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return 0;
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}
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static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
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{
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if (unlikely(info->lo_encrypt_key_size <= 0))
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return -EINVAL;
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return 0;
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}
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static struct loop_func_table none_funcs = {
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.number = LO_CRYPT_NONE,
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.transfer = transfer_none,
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};
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static struct loop_func_table xor_funcs = {
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.number = LO_CRYPT_XOR,
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.transfer = transfer_xor,
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.init = xor_init
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};
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/* xfer_funcs[0] is special - its release function is never called */
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static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
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&none_funcs,
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&xor_funcs
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};
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static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
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{
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loff_t loopsize;
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/* Compute loopsize in bytes */
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loopsize = i_size_read(file->f_mapping->host);
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if (offset > 0)
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loopsize -= offset;
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/* offset is beyond i_size, weird but possible */
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if (loopsize < 0)
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return 0;
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if (sizelimit > 0 && sizelimit < loopsize)
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loopsize = sizelimit;
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/*
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* Unfortunately, if we want to do I/O on the device,
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* the number of 512-byte sectors has to fit into a sector_t.
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*/
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return loopsize >> 9;
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}
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static loff_t get_loop_size(struct loop_device *lo, struct file *file)
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{
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return get_size(lo->lo_offset, lo->lo_sizelimit, file);
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}
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static int
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figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
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{
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loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
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sector_t x = (sector_t)size;
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struct block_device *bdev = lo->lo_device;
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if (unlikely((loff_t)x != size))
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return -EFBIG;
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if (lo->lo_offset != offset)
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lo->lo_offset = offset;
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if (lo->lo_sizelimit != sizelimit)
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lo->lo_sizelimit = sizelimit;
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set_capacity(lo->lo_disk, x);
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bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
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/* let user-space know about the new size */
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kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
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return 0;
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}
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static inline int
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lo_do_transfer(struct loop_device *lo, int cmd,
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struct page *rpage, unsigned roffs,
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struct page *lpage, unsigned loffs,
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int size, sector_t rblock)
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{
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if (unlikely(!lo->transfer))
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return 0;
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return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
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}
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/**
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* __do_lo_send_write - helper for writing data to a loop device
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*
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* This helper just factors out common code between do_lo_send_direct_write()
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* and do_lo_send_write().
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*/
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static int __do_lo_send_write(struct file *file,
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u8 *buf, const int len, loff_t pos)
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{
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ssize_t bw;
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mm_segment_t old_fs = get_fs();
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file_start_write(file);
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set_fs(get_ds());
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bw = file->f_op->write(file, buf, len, &pos);
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set_fs(old_fs);
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file_end_write(file);
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if (likely(bw == len))
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return 0;
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printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n",
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(unsigned long long)pos, len);
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if (bw >= 0)
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bw = -EIO;
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return bw;
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}
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/**
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* do_lo_send_direct_write - helper for writing data to a loop device
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*
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* This is the fast, non-transforming version that does not need double
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* buffering.
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*/
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static int do_lo_send_direct_write(struct loop_device *lo,
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struct bio_vec *bvec, loff_t pos, struct page *page)
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{
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ssize_t bw = __do_lo_send_write(lo->lo_backing_file,
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kmap(bvec->bv_page) + bvec->bv_offset,
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bvec->bv_len, pos);
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kunmap(bvec->bv_page);
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cond_resched();
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return bw;
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}
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/**
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* do_lo_send_write - helper for writing data to a loop device
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*
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* This is the slow, transforming version that needs to double buffer the
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* data as it cannot do the transformations in place without having direct
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* access to the destination pages of the backing file.
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*/
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static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
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loff_t pos, struct page *page)
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{
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int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,
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bvec->bv_offset, bvec->bv_len, pos >> 9);
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if (likely(!ret))
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return __do_lo_send_write(lo->lo_backing_file,
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page_address(page), bvec->bv_len,
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pos);
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printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, "
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"length %i.\n", (unsigned long long)pos, bvec->bv_len);
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if (ret > 0)
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ret = -EIO;
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return ret;
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}
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static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos)
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{
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int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,
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struct page *page);
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struct bio_vec bvec;
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struct bvec_iter iter;
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struct page *page = NULL;
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int ret = 0;
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if (lo->transfer != transfer_none) {
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page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
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if (unlikely(!page))
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goto fail;
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kmap(page);
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do_lo_send = do_lo_send_write;
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} else {
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do_lo_send = do_lo_send_direct_write;
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}
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bio_for_each_segment(bvec, bio, iter) {
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ret = do_lo_send(lo, &bvec, pos, page);
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if (ret < 0)
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break;
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pos += bvec.bv_len;
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}
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if (page) {
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kunmap(page);
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__free_page(page);
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}
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out:
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return ret;
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fail:
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printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n");
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ret = -ENOMEM;
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goto out;
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}
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struct lo_read_data {
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struct loop_device *lo;
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struct page *page;
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unsigned offset;
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int bsize;
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};
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static int
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lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
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struct splice_desc *sd)
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{
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struct lo_read_data *p = sd->u.data;
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struct loop_device *lo = p->lo;
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struct page *page = buf->page;
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sector_t IV;
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int size;
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IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +
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(buf->offset >> 9);
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size = sd->len;
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if (size > p->bsize)
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size = p->bsize;
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if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) {
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printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n",
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page->index);
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size = -EINVAL;
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}
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flush_dcache_page(p->page);
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if (size > 0)
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p->offset += size;
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return size;
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}
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static int
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lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
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{
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return __splice_from_pipe(pipe, sd, lo_splice_actor);
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}
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static ssize_t
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do_lo_receive(struct loop_device *lo,
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struct bio_vec *bvec, int bsize, loff_t pos)
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{
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struct lo_read_data cookie;
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struct splice_desc sd;
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struct file *file;
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ssize_t retval;
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cookie.lo = lo;
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cookie.page = bvec->bv_page;
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cookie.offset = bvec->bv_offset;
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cookie.bsize = bsize;
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sd.len = 0;
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sd.total_len = bvec->bv_len;
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sd.flags = 0;
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sd.pos = pos;
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sd.u.data = &cookie;
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file = lo->lo_backing_file;
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retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
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return retval;
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}
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static int
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lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
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{
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struct bio_vec bvec;
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struct bvec_iter iter;
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ssize_t s;
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bio_for_each_segment(bvec, bio, iter) {
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s = do_lo_receive(lo, &bvec, bsize, pos);
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if (s < 0)
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return s;
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if (s != bvec.bv_len) {
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zero_fill_bio(bio);
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break;
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}
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pos += bvec.bv_len;
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}
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return 0;
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}
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static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
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{
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loff_t pos;
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int ret;
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pos = ((loff_t) bio->bi_iter.bi_sector << 9) + lo->lo_offset;
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if (bio_rw(bio) == WRITE) {
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struct file *file = lo->lo_backing_file;
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if (bio->bi_rw & REQ_FLUSH) {
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ret = vfs_fsync(file, 0);
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if (unlikely(ret && ret != -EINVAL)) {
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ret = -EIO;
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goto out;
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}
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}
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/*
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* We use punch hole to reclaim the free space used by the
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* image a.k.a. discard. However we do not support discard if
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* encryption is enabled, because it may give an attacker
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* useful information.
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*/
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if (bio->bi_rw & REQ_DISCARD) {
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struct file *file = lo->lo_backing_file;
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int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
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if ((!file->f_op->fallocate) ||
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lo->lo_encrypt_key_size) {
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ret = -EOPNOTSUPP;
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goto out;
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}
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ret = file->f_op->fallocate(file, mode, pos,
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bio->bi_iter.bi_size);
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if (unlikely(ret && ret != -EINVAL &&
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ret != -EOPNOTSUPP))
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ret = -EIO;
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goto out;
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}
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ret = lo_send(lo, bio, pos);
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if ((bio->bi_rw & REQ_FUA) && !ret) {
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ret = vfs_fsync(file, 0);
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if (unlikely(ret && ret != -EINVAL))
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ret = -EIO;
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}
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} else
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ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
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out:
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return ret;
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}
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/*
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* Add bio to back of pending list
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*/
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static void loop_add_bio(struct loop_device *lo, struct bio *bio)
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{
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lo->lo_bio_count++;
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bio_list_add(&lo->lo_bio_list, bio);
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}
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/*
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* Grab first pending buffer
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*/
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static struct bio *loop_get_bio(struct loop_device *lo)
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{
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lo->lo_bio_count--;
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return bio_list_pop(&lo->lo_bio_list);
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}
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static void loop_make_request(struct request_queue *q, struct bio *old_bio)
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{
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struct loop_device *lo = q->queuedata;
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int rw = bio_rw(old_bio);
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if (rw == READA)
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rw = READ;
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BUG_ON(!lo || (rw != READ && rw != WRITE));
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spin_lock_irq(&lo->lo_lock);
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if (lo->lo_state != Lo_bound)
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goto out;
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if (unlikely(rw == WRITE && (lo->lo_flags & LO_FLAGS_READ_ONLY)))
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goto out;
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if (lo->lo_bio_count >= q->nr_congestion_on)
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wait_event_lock_irq(lo->lo_req_wait,
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lo->lo_bio_count < q->nr_congestion_off,
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lo->lo_lock);
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loop_add_bio(lo, old_bio);
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wake_up(&lo->lo_event);
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spin_unlock_irq(&lo->lo_lock);
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return;
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|
|
out:
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
bio_io_error(old_bio);
|
|
}
|
|
|
|
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, MIN_NICE);
|
|
|
|
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);
|
|
if (lo->lo_bio_count < lo->lo_queue->nr_congestion_off)
|
|
wake_up(&lo->lo_req_wait);
|
|
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;
|
|
|
|
/* 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 (lo->lo_flags & LO_FLAGS_PARTSCAN)
|
|
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;
|
|
}
|
|
|
|
/* loop sysfs attributes */
|
|
|
|
static ssize_t loop_attr_show(struct device *dev, char *page,
|
|
ssize_t (*callback)(struct loop_device *, char *))
|
|
{
|
|
struct gendisk *disk = dev_to_disk(dev);
|
|
struct loop_device *lo = disk->private_data;
|
|
|
|
return callback(lo, page);
|
|
}
|
|
|
|
#define LOOP_ATTR_RO(_name) \
|
|
static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \
|
|
static ssize_t loop_attr_do_show_##_name(struct device *d, \
|
|
struct device_attribute *attr, char *b) \
|
|
{ \
|
|
return loop_attr_show(d, b, loop_attr_##_name##_show); \
|
|
} \
|
|
static struct device_attribute loop_attr_##_name = \
|
|
__ATTR(_name, S_IRUGO, loop_attr_do_show_##_name, NULL);
|
|
|
|
static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf)
|
|
{
|
|
ssize_t ret;
|
|
char *p = NULL;
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
if (lo->lo_backing_file)
|
|
p = d_path(&lo->lo_backing_file->f_path, buf, PAGE_SIZE - 1);
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
if (IS_ERR_OR_NULL(p))
|
|
ret = PTR_ERR(p);
|
|
else {
|
|
ret = strlen(p);
|
|
memmove(buf, p, ret);
|
|
buf[ret++] = '\n';
|
|
buf[ret] = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf)
|
|
{
|
|
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset);
|
|
}
|
|
|
|
static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf)
|
|
{
|
|
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
|
|
}
|
|
|
|
static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf)
|
|
{
|
|
int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR);
|
|
|
|
return sprintf(buf, "%s\n", autoclear ? "1" : "0");
|
|
}
|
|
|
|
static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf)
|
|
{
|
|
int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN);
|
|
|
|
return sprintf(buf, "%s\n", partscan ? "1" : "0");
|
|
}
|
|
|
|
LOOP_ATTR_RO(backing_file);
|
|
LOOP_ATTR_RO(offset);
|
|
LOOP_ATTR_RO(sizelimit);
|
|
LOOP_ATTR_RO(autoclear);
|
|
LOOP_ATTR_RO(partscan);
|
|
|
|
static struct attribute *loop_attrs[] = {
|
|
&loop_attr_backing_file.attr,
|
|
&loop_attr_offset.attr,
|
|
&loop_attr_sizelimit.attr,
|
|
&loop_attr_autoclear.attr,
|
|
&loop_attr_partscan.attr,
|
|
NULL,
|
|
};
|
|
|
|
static struct attribute_group loop_attribute_group = {
|
|
.name = "loop",
|
|
.attrs= loop_attrs,
|
|
};
|
|
|
|
static int loop_sysfs_init(struct loop_device *lo)
|
|
{
|
|
return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
|
|
&loop_attribute_group);
|
|
}
|
|
|
|
static void loop_sysfs_exit(struct loop_device *lo)
|
|
{
|
|
sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
|
|
&loop_attribute_group);
|
|
}
|
|
|
|
static void loop_config_discard(struct loop_device *lo)
|
|
{
|
|
struct file *file = lo->lo_backing_file;
|
|
struct inode *inode = file->f_mapping->host;
|
|
struct request_queue *q = lo->lo_queue;
|
|
|
|
/*
|
|
* We use punch hole to reclaim the free space used by the
|
|
* image a.k.a. discard. However we do not support discard if
|
|
* encryption is enabled, because it may give an attacker
|
|
* useful information.
|
|
*/
|
|
if ((!file->f_op->fallocate) ||
|
|
lo->lo_encrypt_key_size) {
|
|
q->limits.discard_granularity = 0;
|
|
q->limits.discard_alignment = 0;
|
|
q->limits.max_discard_sectors = 0;
|
|
q->limits.discard_zeroes_data = 0;
|
|
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
|
|
return;
|
|
}
|
|
|
|
q->limits.discard_granularity = inode->i_sb->s_blocksize;
|
|
q->limits.discard_alignment = 0;
|
|
q->limits.max_discard_sectors = UINT_MAX >> 9;
|
|
q->limits.discard_zeroes_data = 1;
|
|
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
|
|
}
|
|
|
|
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;
|
|
|
|
error = -EINVAL;
|
|
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
|
|
goto out_putf;
|
|
|
|
if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
|
|
!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 = -EFBIG;
|
|
size = get_loop_size(lo, file);
|
|
if ((loff_t)(sector_t)size != size)
|
|
goto out_putf;
|
|
|
|
error = 0;
|
|
|
|
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->lo_bio_count = 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);
|
|
|
|
if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
|
|
blk_queue_flush(lo->lo_queue, REQ_FLUSH);
|
|
|
|
set_capacity(lo->lo_disk, size);
|
|
bd_set_size(bdev, size << 9);
|
|
loop_sysfs_init(lo);
|
|
/* let user-space know about the new size */
|
|
kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
|
|
|
|
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 (part_shift)
|
|
lo->lo_flags |= LO_FLAGS_PARTSCAN;
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN)
|
|
ioctl_by_bdev(bdev, BLKRRPART, 0);
|
|
|
|
/* Grab the block_device to prevent its destruction after we
|
|
* put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev).
|
|
*/
|
|
bdgrab(bdev);
|
|
return 0;
|
|
|
|
out_clr:
|
|
loop_sysfs_exit(lo);
|
|
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);
|
|
kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
|
|
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 file *filp = lo->lo_backing_file;
|
|
gfp_t gfp = lo->old_gfp_mask;
|
|
struct block_device *bdev = lo->lo_device;
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
return -ENXIO;
|
|
|
|
/*
|
|
* If we've explicitly asked to tear down the loop device,
|
|
* and it has an elevated reference count, set it for auto-teardown when
|
|
* the last reference goes away. This stops $!~#$@ udev from
|
|
* preventing teardown because it decided that it needs to run blkid on
|
|
* the loopback device whenever they appear. xfstests is notorious for
|
|
* failing tests because blkid via udev races with a losetup
|
|
* <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d
|
|
* command to fail with EBUSY.
|
|
*/
|
|
if (lo->lo_refcnt > 1) {
|
|
lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return 0;
|
|
}
|
|
|
|
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);
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
lo->lo_backing_file = NULL;
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
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_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) {
|
|
bdput(bdev);
|
|
invalidate_bdev(bdev);
|
|
}
|
|
set_capacity(lo->lo_disk, 0);
|
|
loop_sysfs_exit(lo);
|
|
if (bdev) {
|
|
bd_set_size(bdev, 0);
|
|
/* let user-space know about this change */
|
|
kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
|
|
}
|
|
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 (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
|
|
ioctl_by_bdev(bdev, BLKRRPART, 0);
|
|
lo->lo_flags = 0;
|
|
if (!part_shift)
|
|
lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
|
|
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;
|
|
kuid_t uid = current_uid();
|
|
|
|
if (lo->lo_encrypt_key_size &&
|
|
!uid_eq(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)
|
|
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
|
|
return -EFBIG;
|
|
|
|
loop_config_discard(lo);
|
|
|
|
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;
|
|
|
|
if ((info->lo_flags & LO_FLAGS_PARTSCAN) &&
|
|
!(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
|
|
lo->lo_flags |= LO_FLAGS_PARTSCAN;
|
|
lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
|
|
ioctl_by_bdev(lo->lo_device, BLKRRPART, 0);
|
|
}
|
|
|
|
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, &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)
|
|
{
|
|
if (unlikely(lo->lo_state != Lo_bound))
|
|
return -ENXIO;
|
|
|
|
return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit);
|
|
}
|
|
|
|
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);
|
|
if (!err)
|
|
goto out_unlocked;
|
|
break;
|
|
case LOOP_SET_STATUS:
|
|
err = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
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 = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
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;
|
|
int err = 0;
|
|
|
|
mutex_lock(&loop_index_mutex);
|
|
lo = bdev->bd_disk->private_data;
|
|
if (!lo) {
|
|
err = -ENXIO;
|
|
goto out;
|
|
}
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
lo->lo_refcnt++;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
out:
|
|
mutex_unlock(&loop_index_mutex);
|
|
return err;
|
|
}
|
|
|
|
static void 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);
|
|
if (!err)
|
|
return;
|
|
} 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);
|
|
}
|
|
|
|
static const 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, S_IRUGO);
|
|
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
|
|
module_param(max_part, int, S_IRUGO);
|
|
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;
|
|
}
|
|
|
|
static int unregister_transfer_cb(int id, void *ptr, void *data)
|
|
{
|
|
struct loop_device *lo = ptr;
|
|
struct loop_func_table *xfer = data;
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
if (lo->lo_encryption == xfer)
|
|
loop_release_xfer(lo);
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return 0;
|
|
}
|
|
|
|
int loop_unregister_transfer(int number)
|
|
{
|
|
unsigned int n = number;
|
|
struct loop_func_table *xfer;
|
|
|
|
if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
|
|
return -EINVAL;
|
|
|
|
xfer_funcs[n] = NULL;
|
|
idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(loop_register_transfer);
|
|
EXPORT_SYMBOL(loop_unregister_transfer);
|
|
|
|
static int loop_add(struct loop_device **l, int i)
|
|
{
|
|
struct loop_device *lo;
|
|
struct gendisk *disk;
|
|
int err;
|
|
|
|
err = -ENOMEM;
|
|
lo = kzalloc(sizeof(*lo), GFP_KERNEL);
|
|
if (!lo)
|
|
goto out;
|
|
|
|
lo->lo_state = Lo_unbound;
|
|
|
|
/* allocate id, if @id >= 0, we're requesting that specific id */
|
|
if (i >= 0) {
|
|
err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL);
|
|
if (err == -ENOSPC)
|
|
err = -EEXIST;
|
|
} else {
|
|
err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL);
|
|
}
|
|
if (err < 0)
|
|
goto out_free_dev;
|
|
i = err;
|
|
|
|
err = -ENOMEM;
|
|
lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
|
|
if (!lo->lo_queue)
|
|
goto out_free_idr;
|
|
|
|
/*
|
|
* set queue make_request_fn
|
|
*/
|
|
blk_queue_make_request(lo->lo_queue, loop_make_request);
|
|
lo->lo_queue->queuedata = lo;
|
|
|
|
disk = lo->lo_disk = alloc_disk(1 << part_shift);
|
|
if (!disk)
|
|
goto out_free_queue;
|
|
|
|
/*
|
|
* Disable partition scanning by default. The in-kernel partition
|
|
* scanning can be requested individually per-device during its
|
|
* setup. Userspace can always add and remove partitions from all
|
|
* devices. The needed partition minors are allocated from the
|
|
* extended minor space, the main loop device numbers will continue
|
|
* to match the loop minors, regardless of the number of partitions
|
|
* used.
|
|
*
|
|
* If max_part is given, partition scanning is globally enabled for
|
|
* all loop devices. The minors for the main loop devices will be
|
|
* multiples of max_part.
|
|
*
|
|
* Note: Global-for-all-devices, set-only-at-init, read-only module
|
|
* parameteters like 'max_loop' and 'max_part' make things needlessly
|
|
* complicated, are too static, inflexible and may surprise
|
|
* userspace tools. Parameters like this in general should be avoided.
|
|
*/
|
|
if (!part_shift)
|
|
disk->flags |= GENHD_FL_NO_PART_SCAN;
|
|
disk->flags |= GENHD_FL_EXT_DEVT;
|
|
mutex_init(&lo->lo_ctl_mutex);
|
|
lo->lo_number = i;
|
|
lo->lo_thread = NULL;
|
|
init_waitqueue_head(&lo->lo_event);
|
|
init_waitqueue_head(&lo->lo_req_wait);
|
|
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);
|
|
add_disk(disk);
|
|
*l = lo;
|
|
return lo->lo_number;
|
|
|
|
out_free_queue:
|
|
blk_cleanup_queue(lo->lo_queue);
|
|
out_free_idr:
|
|
idr_remove(&loop_index_idr, i);
|
|
out_free_dev:
|
|
kfree(lo);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static void loop_remove(struct loop_device *lo)
|
|
{
|
|
del_gendisk(lo->lo_disk);
|
|
blk_cleanup_queue(lo->lo_queue);
|
|
put_disk(lo->lo_disk);
|
|
kfree(lo);
|
|
}
|
|
|
|
static int find_free_cb(int id, void *ptr, void *data)
|
|
{
|
|
struct loop_device *lo = ptr;
|
|
struct loop_device **l = data;
|
|
|
|
if (lo->lo_state == Lo_unbound) {
|
|
*l = lo;
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int loop_lookup(struct loop_device **l, int i)
|
|
{
|
|
struct loop_device *lo;
|
|
int ret = -ENODEV;
|
|
|
|
if (i < 0) {
|
|
int err;
|
|
|
|
err = idr_for_each(&loop_index_idr, &find_free_cb, &lo);
|
|
if (err == 1) {
|
|
*l = lo;
|
|
ret = lo->lo_number;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
/* lookup and return a specific i */
|
|
lo = idr_find(&loop_index_idr, i);
|
|
if (lo) {
|
|
*l = lo;
|
|
ret = lo->lo_number;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static struct kobject *loop_probe(dev_t dev, int *part, void *data)
|
|
{
|
|
struct loop_device *lo;
|
|
struct kobject *kobj;
|
|
int err;
|
|
|
|
mutex_lock(&loop_index_mutex);
|
|
err = loop_lookup(&lo, MINOR(dev) >> part_shift);
|
|
if (err < 0)
|
|
err = loop_add(&lo, MINOR(dev) >> part_shift);
|
|
if (err < 0)
|
|
kobj = NULL;
|
|
else
|
|
kobj = get_disk(lo->lo_disk);
|
|
mutex_unlock(&loop_index_mutex);
|
|
|
|
*part = 0;
|
|
return kobj;
|
|
}
|
|
|
|
static long loop_control_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long parm)
|
|
{
|
|
struct loop_device *lo;
|
|
int ret = -ENOSYS;
|
|
|
|
mutex_lock(&loop_index_mutex);
|
|
switch (cmd) {
|
|
case LOOP_CTL_ADD:
|
|
ret = loop_lookup(&lo, parm);
|
|
if (ret >= 0) {
|
|
ret = -EEXIST;
|
|
break;
|
|
}
|
|
ret = loop_add(&lo, parm);
|
|
break;
|
|
case LOOP_CTL_REMOVE:
|
|
ret = loop_lookup(&lo, parm);
|
|
if (ret < 0)
|
|
break;
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
if (lo->lo_state != Lo_unbound) {
|
|
ret = -EBUSY;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
break;
|
|
}
|
|
if (lo->lo_refcnt > 0) {
|
|
ret = -EBUSY;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
break;
|
|
}
|
|
lo->lo_disk->private_data = NULL;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
idr_remove(&loop_index_idr, lo->lo_number);
|
|
loop_remove(lo);
|
|
break;
|
|
case LOOP_CTL_GET_FREE:
|
|
ret = loop_lookup(&lo, -1);
|
|
if (ret >= 0)
|
|
break;
|
|
ret = loop_add(&lo, -1);
|
|
}
|
|
mutex_unlock(&loop_index_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations loop_ctl_fops = {
|
|
.open = nonseekable_open,
|
|
.unlocked_ioctl = loop_control_ioctl,
|
|
.compat_ioctl = loop_control_ioctl,
|
|
.owner = THIS_MODULE,
|
|
.llseek = noop_llseek,
|
|
};
|
|
|
|
static struct miscdevice loop_misc = {
|
|
.minor = LOOP_CTRL_MINOR,
|
|
.name = "loop-control",
|
|
.fops = &loop_ctl_fops,
|
|
};
|
|
|
|
MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR);
|
|
MODULE_ALIAS("devname:loop-control");
|
|
|
|
static int __init loop_init(void)
|
|
{
|
|
int i, nr;
|
|
unsigned long range;
|
|
struct loop_device *lo;
|
|
int err;
|
|
|
|
err = misc_register(&loop_misc);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
part_shift = 0;
|
|
if (max_part > 0) {
|
|
part_shift = fls(max_part);
|
|
|
|
/*
|
|
* Adjust max_part according to part_shift as it is exported
|
|
* to user space so that user can decide correct minor number
|
|
* if [s]he want to create more devices.
|
|
*
|
|
* Note that -1 is required because partition 0 is reserved
|
|
* for the whole disk.
|
|
*/
|
|
max_part = (1UL << part_shift) - 1;
|
|
}
|
|
|
|
if ((1UL << part_shift) > DISK_MAX_PARTS) {
|
|
err = -EINVAL;
|
|
goto misc_out;
|
|
}
|
|
|
|
if (max_loop > 1UL << (MINORBITS - part_shift)) {
|
|
err = -EINVAL;
|
|
goto misc_out;
|
|
}
|
|
|
|
/*
|
|
* If max_loop is specified, create that many devices upfront.
|
|
* This also becomes a hard limit. If max_loop is not specified,
|
|
* create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module
|
|
* init time. Loop devices can be requested on-demand with the
|
|
* /dev/loop-control interface, or be instantiated by accessing
|
|
* a 'dead' device node.
|
|
*/
|
|
if (max_loop) {
|
|
nr = max_loop;
|
|
range = max_loop << part_shift;
|
|
} else {
|
|
nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
|
|
range = 1UL << MINORBITS;
|
|
}
|
|
|
|
if (register_blkdev(LOOP_MAJOR, "loop")) {
|
|
err = -EIO;
|
|
goto misc_out;
|
|
}
|
|
|
|
blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
|
|
THIS_MODULE, loop_probe, NULL, NULL);
|
|
|
|
/* pre-create number of devices given by config or max_loop */
|
|
mutex_lock(&loop_index_mutex);
|
|
for (i = 0; i < nr; i++)
|
|
loop_add(&lo, i);
|
|
mutex_unlock(&loop_index_mutex);
|
|
|
|
printk(KERN_INFO "loop: module loaded\n");
|
|
return 0;
|
|
|
|
misc_out:
|
|
misc_deregister(&loop_misc);
|
|
return err;
|
|
}
|
|
|
|
static int loop_exit_cb(int id, void *ptr, void *data)
|
|
{
|
|
struct loop_device *lo = ptr;
|
|
|
|
loop_remove(lo);
|
|
return 0;
|
|
}
|
|
|
|
static void __exit loop_exit(void)
|
|
{
|
|
unsigned long range;
|
|
|
|
range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;
|
|
|
|
idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
|
|
idr_destroy(&loop_index_idr);
|
|
|
|
blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
|
|
unregister_blkdev(LOOP_MAJOR, "loop");
|
|
|
|
misc_deregister(&loop_misc);
|
|
}
|
|
|
|
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
|