mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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bdac616db9
Commit2d1d4c1e59
made loop_get_status() drop lo_ctx_mutex before returning, but the loop_get_status_old(), loop_get_status64(), and loop_get_status_compat() wrappers don't call loop_get_status() if the passed argument is NULL. The callers expect that the lock is dropped, so make sure we drop it in that case, too. Reported-by: syzbot+31e8daa8b3fc129e75f2@syzkaller.appspotmail.com Fixes:2d1d4c1e59
("loop: don't call into filesystem while holding lo_ctl_mutex") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2133 lines
52 KiB
C
2133 lines
52 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 <linux/uio.h>
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#include "loop.h"
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#include <linux/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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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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};
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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 void __loop_update_dio(struct loop_device *lo, bool dio)
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{
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struct file *file = lo->lo_backing_file;
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struct address_space *mapping = file->f_mapping;
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struct inode *inode = mapping->host;
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unsigned short sb_bsize = 0;
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unsigned dio_align = 0;
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bool use_dio;
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if (inode->i_sb->s_bdev) {
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sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
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dio_align = sb_bsize - 1;
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}
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/*
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* We support direct I/O only if lo_offset is aligned with the
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* logical I/O size of backing device, and the logical block
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* size of loop is bigger than the backing device's and the loop
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* needn't transform transfer.
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*
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* TODO: the above condition may be loosed in the future, and
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* direct I/O may be switched runtime at that time because most
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* of requests in sane applications should be PAGE_SIZE aligned
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*/
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if (dio) {
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if (queue_logical_block_size(lo->lo_queue) >= sb_bsize &&
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!(lo->lo_offset & dio_align) &&
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mapping->a_ops->direct_IO &&
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!lo->transfer)
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use_dio = true;
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else
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use_dio = false;
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} else {
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use_dio = false;
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}
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if (lo->use_dio == use_dio)
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return;
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/* flush dirty pages before changing direct IO */
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vfs_fsync(file, 0);
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/*
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* The flag of LO_FLAGS_DIRECT_IO is handled similarly with
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* LO_FLAGS_READ_ONLY, both are set from kernel, and losetup
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* will get updated by ioctl(LOOP_GET_STATUS)
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*/
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blk_mq_freeze_queue(lo->lo_queue);
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lo->use_dio = use_dio;
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if (use_dio) {
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blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue);
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lo->lo_flags |= LO_FLAGS_DIRECT_IO;
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} else {
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blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue);
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lo->lo_flags &= ~LO_FLAGS_DIRECT_IO;
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}
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blk_mq_unfreeze_queue(lo->lo_queue);
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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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int ret;
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ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
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if (likely(!ret))
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return 0;
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printk_ratelimited(KERN_ERR
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"loop: Transfer error at byte offset %llu, length %i.\n",
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(unsigned long long)rblock << 9, size);
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return ret;
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}
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static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
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{
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struct iov_iter i;
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ssize_t bw;
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iov_iter_bvec(&i, ITER_BVEC | WRITE, bvec, 1, bvec->bv_len);
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file_start_write(file);
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bw = vfs_iter_write(file, &i, ppos, 0);
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file_end_write(file);
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if (likely(bw == bvec->bv_len))
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return 0;
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printk_ratelimited(KERN_ERR
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"loop: Write error at byte offset %llu, length %i.\n",
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(unsigned long long)*ppos, bvec->bv_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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static int lo_write_simple(struct loop_device *lo, struct request *rq,
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loff_t pos)
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{
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struct bio_vec bvec;
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struct req_iterator iter;
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int ret = 0;
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rq_for_each_segment(bvec, rq, iter) {
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ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
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if (ret < 0)
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break;
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cond_resched();
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}
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return ret;
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}
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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 lo_write_transfer(struct loop_device *lo, struct request *rq,
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loff_t pos)
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{
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struct bio_vec bvec, b;
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struct req_iterator iter;
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struct page *page;
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int ret = 0;
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page = alloc_page(GFP_NOIO);
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if (unlikely(!page))
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return -ENOMEM;
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rq_for_each_segment(bvec, rq, iter) {
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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 (unlikely(ret))
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break;
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b.bv_page = page;
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b.bv_offset = 0;
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b.bv_len = bvec.bv_len;
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ret = lo_write_bvec(lo->lo_backing_file, &b, &pos);
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if (ret < 0)
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break;
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}
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__free_page(page);
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return ret;
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}
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static int lo_read_simple(struct loop_device *lo, struct request *rq,
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loff_t pos)
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{
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struct bio_vec bvec;
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struct req_iterator iter;
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struct iov_iter i;
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ssize_t len;
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rq_for_each_segment(bvec, rq, iter) {
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iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);
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len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
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if (len < 0)
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return len;
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flush_dcache_page(bvec.bv_page);
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if (len != bvec.bv_len) {
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struct bio *bio;
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__rq_for_each_bio(bio, rq)
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zero_fill_bio(bio);
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break;
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}
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cond_resched();
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}
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return 0;
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}
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static int lo_read_transfer(struct loop_device *lo, struct request *rq,
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loff_t pos)
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{
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struct bio_vec bvec, b;
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struct req_iterator iter;
|
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struct iov_iter i;
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struct page *page;
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ssize_t len;
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int ret = 0;
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page = alloc_page(GFP_NOIO);
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if (unlikely(!page))
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return -ENOMEM;
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rq_for_each_segment(bvec, rq, iter) {
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loff_t offset = pos;
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b.bv_page = page;
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b.bv_offset = 0;
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b.bv_len = bvec.bv_len;
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iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);
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len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
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if (len < 0) {
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ret = len;
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goto out_free_page;
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}
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ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page,
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bvec.bv_offset, len, offset >> 9);
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if (ret)
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goto out_free_page;
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flush_dcache_page(bvec.bv_page);
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|
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if (len != bvec.bv_len) {
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struct bio *bio;
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__rq_for_each_bio(bio, rq)
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zero_fill_bio(bio);
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break;
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}
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}
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|
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ret = 0;
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out_free_page:
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__free_page(page);
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return ret;
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}
|
|
|
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static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
|
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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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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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int ret;
|
|
|
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if ((!file->f_op->fallocate) || 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, blk_rq_bytes(rq));
|
|
if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
|
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ret = -EIO;
|
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out:
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return ret;
|
|
}
|
|
|
|
static int lo_req_flush(struct loop_device *lo, struct request *rq)
|
|
{
|
|
struct file *file = lo->lo_backing_file;
|
|
int ret = vfs_fsync(file, 0);
|
|
if (unlikely(ret && ret != -EINVAL))
|
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ret = -EIO;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void lo_complete_rq(struct request *rq)
|
|
{
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
|
|
|
|
if (unlikely(req_op(cmd->rq) == REQ_OP_READ && cmd->use_aio &&
|
|
cmd->ret >= 0 && cmd->ret < blk_rq_bytes(cmd->rq))) {
|
|
struct bio *bio = cmd->rq->bio;
|
|
|
|
bio_advance(bio, cmd->ret);
|
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zero_fill_bio(bio);
|
|
}
|
|
|
|
blk_mq_end_request(rq, cmd->ret < 0 ? BLK_STS_IOERR : BLK_STS_OK);
|
|
}
|
|
|
|
static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
|
|
{
|
|
if (!atomic_dec_and_test(&cmd->ref))
|
|
return;
|
|
kfree(cmd->bvec);
|
|
cmd->bvec = NULL;
|
|
blk_mq_complete_request(cmd->rq);
|
|
}
|
|
|
|
static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
|
|
{
|
|
struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb);
|
|
|
|
if (cmd->css)
|
|
css_put(cmd->css);
|
|
cmd->ret = ret;
|
|
lo_rw_aio_do_completion(cmd);
|
|
}
|
|
|
|
static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
|
|
loff_t pos, bool rw)
|
|
{
|
|
struct iov_iter iter;
|
|
struct bio_vec *bvec;
|
|
struct request *rq = cmd->rq;
|
|
struct bio *bio = rq->bio;
|
|
struct file *file = lo->lo_backing_file;
|
|
unsigned int offset;
|
|
int segments = 0;
|
|
int ret;
|
|
|
|
if (rq->bio != rq->biotail) {
|
|
struct req_iterator iter;
|
|
struct bio_vec tmp;
|
|
|
|
__rq_for_each_bio(bio, rq)
|
|
segments += bio_segments(bio);
|
|
bvec = kmalloc(sizeof(struct bio_vec) * segments, GFP_NOIO);
|
|
if (!bvec)
|
|
return -EIO;
|
|
cmd->bvec = bvec;
|
|
|
|
/*
|
|
* The bios of the request may be started from the middle of
|
|
* the 'bvec' because of bio splitting, so we can't directly
|
|
* copy bio->bi_iov_vec to new bvec. The rq_for_each_segment
|
|
* API will take care of all details for us.
|
|
*/
|
|
rq_for_each_segment(tmp, rq, iter) {
|
|
*bvec = tmp;
|
|
bvec++;
|
|
}
|
|
bvec = cmd->bvec;
|
|
offset = 0;
|
|
} else {
|
|
/*
|
|
* Same here, this bio may be started from the middle of the
|
|
* 'bvec' because of bio splitting, so offset from the bvec
|
|
* must be passed to iov iterator
|
|
*/
|
|
offset = bio->bi_iter.bi_bvec_done;
|
|
bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
|
|
segments = bio_segments(bio);
|
|
}
|
|
atomic_set(&cmd->ref, 2);
|
|
|
|
iov_iter_bvec(&iter, ITER_BVEC | rw, bvec,
|
|
segments, blk_rq_bytes(rq));
|
|
iter.iov_offset = offset;
|
|
|
|
cmd->iocb.ki_pos = pos;
|
|
cmd->iocb.ki_filp = file;
|
|
cmd->iocb.ki_complete = lo_rw_aio_complete;
|
|
cmd->iocb.ki_flags = IOCB_DIRECT;
|
|
if (cmd->css)
|
|
kthread_associate_blkcg(cmd->css);
|
|
|
|
if (rw == WRITE)
|
|
ret = call_write_iter(file, &cmd->iocb, &iter);
|
|
else
|
|
ret = call_read_iter(file, &cmd->iocb, &iter);
|
|
|
|
lo_rw_aio_do_completion(cmd);
|
|
kthread_associate_blkcg(NULL);
|
|
|
|
if (ret != -EIOCBQUEUED)
|
|
cmd->iocb.ki_complete(&cmd->iocb, ret, 0);
|
|
return 0;
|
|
}
|
|
|
|
static int do_req_filebacked(struct loop_device *lo, struct request *rq)
|
|
{
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
|
|
loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
|
|
|
|
/*
|
|
* lo_write_simple and lo_read_simple should have been covered
|
|
* by io submit style function like lo_rw_aio(), one blocker
|
|
* is that lo_read_simple() need to call flush_dcache_page after
|
|
* the page is written from kernel, and it isn't easy to handle
|
|
* this in io submit style function which submits all segments
|
|
* of the req at one time. And direct read IO doesn't need to
|
|
* run flush_dcache_page().
|
|
*/
|
|
switch (req_op(rq)) {
|
|
case REQ_OP_FLUSH:
|
|
return lo_req_flush(lo, rq);
|
|
case REQ_OP_DISCARD:
|
|
case REQ_OP_WRITE_ZEROES:
|
|
return lo_discard(lo, rq, pos);
|
|
case REQ_OP_WRITE:
|
|
if (lo->transfer)
|
|
return lo_write_transfer(lo, rq, pos);
|
|
else if (cmd->use_aio)
|
|
return lo_rw_aio(lo, cmd, pos, WRITE);
|
|
else
|
|
return lo_write_simple(lo, rq, pos);
|
|
case REQ_OP_READ:
|
|
if (lo->transfer)
|
|
return lo_read_transfer(lo, rq, pos);
|
|
else if (cmd->use_aio)
|
|
return lo_rw_aio(lo, cmd, pos, READ);
|
|
else
|
|
return lo_read_simple(lo, rq, pos);
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
return -EIO;
|
|
break;
|
|
}
|
|
}
|
|
|
|
static inline void loop_update_dio(struct loop_device *lo)
|
|
{
|
|
__loop_update_dio(lo, io_is_direct(lo->lo_backing_file) |
|
|
lo->use_dio);
|
|
}
|
|
|
|
static void loop_reread_partitions(struct loop_device *lo,
|
|
struct block_device *bdev)
|
|
{
|
|
int rc;
|
|
|
|
/*
|
|
* bd_mutex has been held already in release path, so don't
|
|
* acquire it if this function is called in such case.
|
|
*
|
|
* If the reread partition isn't from release path, lo_refcnt
|
|
* must be at least one and it can only become zero when the
|
|
* current holder is released.
|
|
*/
|
|
if (!atomic_read(&lo->lo_refcnt))
|
|
rc = __blkdev_reread_part(bdev);
|
|
else
|
|
rc = blkdev_reread_part(bdev);
|
|
if (rc)
|
|
pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
|
|
__func__, lo->lo_number, lo->lo_file_name, rc);
|
|
}
|
|
|
|
/*
|
|
* 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 */
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
|
|
lo->lo_backing_file = file;
|
|
lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping);
|
|
mapping_set_gfp_mask(file->f_mapping,
|
|
lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
|
loop_update_dio(lo);
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
fput(old_file);
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN)
|
|
loop_reread_partitions(lo, bdev);
|
|
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 = file_path(lo->lo_backing_file, 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");
|
|
}
|
|
|
|
static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf)
|
|
{
|
|
int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO);
|
|
|
|
return sprintf(buf, "%s\n", dio ? "1" : "0");
|
|
}
|
|
|
|
LOOP_ATTR_RO(backing_file);
|
|
LOOP_ATTR_RO(offset);
|
|
LOOP_ATTR_RO(sizelimit);
|
|
LOOP_ATTR_RO(autoclear);
|
|
LOOP_ATTR_RO(partscan);
|
|
LOOP_ATTR_RO(dio);
|
|
|
|
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,
|
|
&loop_attr_dio.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;
|
|
blk_queue_max_discard_sectors(q, 0);
|
|
blk_queue_max_write_zeroes_sectors(q, 0);
|
|
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
|
|
return;
|
|
}
|
|
|
|
q->limits.discard_granularity = inode->i_sb->s_blocksize;
|
|
q->limits.discard_alignment = 0;
|
|
|
|
blk_queue_max_discard_sectors(q, UINT_MAX >> 9);
|
|
blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);
|
|
blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
|
|
}
|
|
|
|
static void loop_unprepare_queue(struct loop_device *lo)
|
|
{
|
|
kthread_flush_worker(&lo->worker);
|
|
kthread_stop(lo->worker_task);
|
|
}
|
|
|
|
static int loop_kthread_worker_fn(void *worker_ptr)
|
|
{
|
|
current->flags |= PF_LESS_THROTTLE;
|
|
return kthread_worker_fn(worker_ptr);
|
|
}
|
|
|
|
static int loop_prepare_queue(struct loop_device *lo)
|
|
{
|
|
kthread_init_worker(&lo->worker);
|
|
lo->worker_task = kthread_run(loop_kthread_worker_fn,
|
|
&lo->worker, "loop%d", lo->lo_number);
|
|
if (IS_ERR(lo->worker_task))
|
|
return -ENOMEM;
|
|
set_user_nice(lo->worker_task, MIN_NICE);
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
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_iter)
|
|
lo_flags |= LO_FLAGS_READ_ONLY;
|
|
|
|
error = -EFBIG;
|
|
size = get_loop_size(lo, file);
|
|
if ((loff_t)(sector_t)size != size)
|
|
goto out_putf;
|
|
error = loop_prepare_queue(lo);
|
|
if (error)
|
|
goto out_putf;
|
|
|
|
error = 0;
|
|
|
|
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
|
|
|
|
lo->use_dio = false;
|
|
lo->lo_device = bdev;
|
|
lo->lo_flags = lo_flags;
|
|
lo->lo_backing_file = file;
|
|
lo->transfer = NULL;
|
|
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));
|
|
|
|
if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
|
|
blk_queue_write_cache(lo->lo_queue, true, false);
|
|
|
|
loop_update_dio(lo);
|
|
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, S_ISBLK(inode->i_mode) ?
|
|
block_size(inode->i_bdev) : PAGE_SIZE);
|
|
|
|
lo->lo_state = Lo_bound;
|
|
if (part_shift)
|
|
lo->lo_flags |= LO_FLAGS_PARTSCAN;
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN)
|
|
loop_reread_partitions(lo, bdev);
|
|
|
|
/* 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_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 (atomic_read(&lo->lo_refcnt) > 1) {
|
|
lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return 0;
|
|
}
|
|
|
|
if (filp == NULL)
|
|
return -EINVAL;
|
|
|
|
/* freeze request queue during the transition */
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
lo->lo_state = Lo_rundown;
|
|
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;
|
|
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);
|
|
blk_queue_logical_block_size(lo->lo_queue, 512);
|
|
blk_queue_physical_block_size(lo->lo_queue, 512);
|
|
blk_queue_io_min(lo->lo_queue, 512);
|
|
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);
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
|
|
loop_reread_partitions(lo, bdev);
|
|
lo->lo_flags = 0;
|
|
if (!part_shift)
|
|
lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
|
|
loop_unprepare_queue(lo);
|
|
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;
|
|
|
|
/* I/O need to be drained during transfer transition */
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
err = loop_release_xfer(lo);
|
|
if (err)
|
|
goto exit;
|
|
|
|
if (info->lo_encrypt_type) {
|
|
unsigned int type = info->lo_encrypt_type;
|
|
|
|
if (type >= MAX_LO_CRYPT) {
|
|
err = -EINVAL;
|
|
goto exit;
|
|
}
|
|
xfer = xfer_funcs[type];
|
|
if (xfer == NULL) {
|
|
err = -EINVAL;
|
|
goto exit;
|
|
}
|
|
} else
|
|
xfer = NULL;
|
|
|
|
err = loop_init_xfer(lo, xfer, info);
|
|
if (err)
|
|
goto exit;
|
|
|
|
if (lo->lo_offset != info->lo_offset ||
|
|
lo->lo_sizelimit != info->lo_sizelimit) {
|
|
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) {
|
|
err = -EFBIG;
|
|
goto exit;
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
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;
|
|
}
|
|
|
|
/* update dio if lo_offset or transfer is changed */
|
|
__loop_update_dio(lo, lo->use_dio);
|
|
|
|
exit:
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
if (!err && (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;
|
|
loop_reread_partitions(lo, lo->lo_device);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
loop_get_status(struct loop_device *lo, struct loop_info64 *info)
|
|
{
|
|
struct file *file;
|
|
struct kstat stat;
|
|
int ret;
|
|
|
|
if (lo->lo_state != Lo_bound) {
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return -ENXIO;
|
|
}
|
|
|
|
memset(info, 0, sizeof(*info));
|
|
info->lo_number = lo->lo_number;
|
|
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);
|
|
}
|
|
|
|
/* Drop lo_ctl_mutex while we call into the filesystem. */
|
|
file = get_file(lo->lo_backing_file);
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
ret = vfs_getattr(&file->f_path, &stat, STATX_INO,
|
|
AT_STATX_SYNC_AS_STAT);
|
|
if (!ret) {
|
|
info->lo_device = huge_encode_dev(stat.dev);
|
|
info->lo_inode = stat.ino;
|
|
info->lo_rdevice = huge_encode_dev(stat.rdev);
|
|
}
|
|
fput(file);
|
|
return ret;
|
|
}
|
|
|
|
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;
|
|
|
|
if (!arg) {
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return -EINVAL;
|
|
}
|
|
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;
|
|
|
|
if (!arg) {
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return -EINVAL;
|
|
}
|
|
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)
|
|
{
|
|
if (unlikely(lo->lo_state != Lo_bound))
|
|
return -ENXIO;
|
|
|
|
return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit);
|
|
}
|
|
|
|
static int loop_set_dio(struct loop_device *lo, unsigned long arg)
|
|
{
|
|
int error = -ENXIO;
|
|
if (lo->lo_state != Lo_bound)
|
|
goto out;
|
|
|
|
__loop_update_dio(lo, !!arg);
|
|
if (lo->use_dio == !!arg)
|
|
return 0;
|
|
error = -EINVAL;
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
|
|
{
|
|
if (lo->lo_state != Lo_bound)
|
|
return -ENXIO;
|
|
|
|
if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg))
|
|
return -EINVAL;
|
|
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
blk_queue_logical_block_size(lo->lo_queue, arg);
|
|
blk_queue_physical_block_size(lo->lo_queue, arg);
|
|
blk_queue_io_min(lo->lo_queue, arg);
|
|
loop_update_dio(lo);
|
|
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
|
|
err = mutex_lock_killable_nested(&lo->lo_ctl_mutex, 1);
|
|
if (err)
|
|
goto out_unlocked;
|
|
|
|
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);
|
|
/* loop_get_status() unlocks lo_ctl_mutex */
|
|
goto out_unlocked;
|
|
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);
|
|
/* loop_get_status() unlocks lo_ctl_mutex */
|
|
goto out_unlocked;
|
|
case LOOP_SET_CAPACITY:
|
|
err = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
err = loop_set_capacity(lo);
|
|
break;
|
|
case LOOP_SET_DIRECT_IO:
|
|
err = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
err = loop_set_dio(lo, arg);
|
|
break;
|
|
case LOOP_SET_BLOCK_SIZE:
|
|
err = -EPERM;
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
err = loop_set_block_size(lo, arg);
|
|
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;
|
|
|
|
if (!arg) {
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
return -EINVAL;
|
|
}
|
|
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:
|
|
err = mutex_lock_killable(&lo->lo_ctl_mutex);
|
|
if (!err) {
|
|
err = loop_set_status_compat(lo,
|
|
(const struct compat_loop_info __user *)arg);
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
}
|
|
break;
|
|
case LOOP_GET_STATUS:
|
|
err = mutex_lock_killable(&lo->lo_ctl_mutex);
|
|
if (!err) {
|
|
err = loop_get_status_compat(lo,
|
|
(struct compat_loop_info __user *)arg);
|
|
/* loop_get_status() unlocks 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;
|
|
}
|
|
|
|
atomic_inc(&lo->lo_refcnt);
|
|
out:
|
|
mutex_unlock(&loop_index_mutex);
|
|
return err;
|
|
}
|
|
|
|
static void __lo_release(struct loop_device *lo)
|
|
{
|
|
int err;
|
|
|
|
if (atomic_dec_return(&lo->lo_refcnt))
|
|
return;
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
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 if (lo->lo_state == Lo_bound) {
|
|
/*
|
|
* Otherwise keep thread (if running) and config,
|
|
* but flush possible ongoing bios in thread.
|
|
*/
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
}
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
}
|
|
|
|
static void lo_release(struct gendisk *disk, fmode_t mode)
|
|
{
|
|
mutex_lock(&loop_index_mutex);
|
|
__lo_release(disk->private_data);
|
|
mutex_unlock(&loop_index_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 blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
|
|
const struct blk_mq_queue_data *bd)
|
|
{
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
|
|
struct loop_device *lo = cmd->rq->q->queuedata;
|
|
|
|
blk_mq_start_request(bd->rq);
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
return BLK_STS_IOERR;
|
|
|
|
switch (req_op(cmd->rq)) {
|
|
case REQ_OP_FLUSH:
|
|
case REQ_OP_DISCARD:
|
|
case REQ_OP_WRITE_ZEROES:
|
|
cmd->use_aio = false;
|
|
break;
|
|
default:
|
|
cmd->use_aio = lo->use_dio;
|
|
break;
|
|
}
|
|
|
|
/* always use the first bio's css */
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
if (cmd->use_aio && cmd->rq->bio && cmd->rq->bio->bi_css) {
|
|
cmd->css = cmd->rq->bio->bi_css;
|
|
css_get(cmd->css);
|
|
} else
|
|
#endif
|
|
cmd->css = NULL;
|
|
kthread_queue_work(&lo->worker, &cmd->work);
|
|
|
|
return BLK_STS_OK;
|
|
}
|
|
|
|
static void loop_handle_cmd(struct loop_cmd *cmd)
|
|
{
|
|
const bool write = op_is_write(req_op(cmd->rq));
|
|
struct loop_device *lo = cmd->rq->q->queuedata;
|
|
int ret = 0;
|
|
|
|
if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) {
|
|
ret = -EIO;
|
|
goto failed;
|
|
}
|
|
|
|
ret = do_req_filebacked(lo, cmd->rq);
|
|
failed:
|
|
/* complete non-aio request */
|
|
if (!cmd->use_aio || ret) {
|
|
cmd->ret = ret ? -EIO : 0;
|
|
blk_mq_complete_request(cmd->rq);
|
|
}
|
|
}
|
|
|
|
static void loop_queue_work(struct kthread_work *work)
|
|
{
|
|
struct loop_cmd *cmd =
|
|
container_of(work, struct loop_cmd, work);
|
|
|
|
loop_handle_cmd(cmd);
|
|
}
|
|
|
|
static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq,
|
|
unsigned int hctx_idx, unsigned int numa_node)
|
|
{
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
|
|
|
|
cmd->rq = rq;
|
|
kthread_init_work(&cmd->work, loop_queue_work);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct blk_mq_ops loop_mq_ops = {
|
|
.queue_rq = loop_queue_rq,
|
|
.init_request = loop_init_request,
|
|
.complete = lo_complete_rq,
|
|
};
|
|
|
|
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->tag_set.ops = &loop_mq_ops;
|
|
lo->tag_set.nr_hw_queues = 1;
|
|
lo->tag_set.queue_depth = 128;
|
|
lo->tag_set.numa_node = NUMA_NO_NODE;
|
|
lo->tag_set.cmd_size = sizeof(struct loop_cmd);
|
|
lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
|
|
lo->tag_set.driver_data = lo;
|
|
|
|
err = blk_mq_alloc_tag_set(&lo->tag_set);
|
|
if (err)
|
|
goto out_free_idr;
|
|
|
|
lo->lo_queue = blk_mq_init_queue(&lo->tag_set);
|
|
if (IS_ERR_OR_NULL(lo->lo_queue)) {
|
|
err = PTR_ERR(lo->lo_queue);
|
|
goto out_cleanup_tags;
|
|
}
|
|
lo->lo_queue->queuedata = lo;
|
|
|
|
blk_queue_max_hw_sectors(lo->lo_queue, BLK_DEF_MAX_SECTORS);
|
|
|
|
/*
|
|
* By default, we do buffer IO, so it doesn't make sense to enable
|
|
* merge because the I/O submitted to backing file is handled page by
|
|
* page. For directio mode, merge does help to dispatch bigger request
|
|
* to underlayer disk. We will enable merge once directio is enabled.
|
|
*/
|
|
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue);
|
|
|
|
err = -ENOMEM;
|
|
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);
|
|
atomic_set(&lo->lo_refcnt, 0);
|
|
lo->lo_number = i;
|
|
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_cleanup_tags:
|
|
blk_mq_free_tag_set(&lo->tag_set);
|
|
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);
|
|
blk_mq_free_tag_set(&lo->tag_set);
|
|
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_and_module(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;
|
|
ret = mutex_lock_killable(&lo->lo_ctl_mutex);
|
|
if (ret)
|
|
break;
|
|
if (lo->lo_state != Lo_unbound) {
|
|
ret = -EBUSY;
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
break;
|
|
}
|
|
if (atomic_read(&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;
|
|
|
|
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 err_out;
|
|
}
|
|
|
|
if (max_loop > 1UL << (MINORBITS - part_shift)) {
|
|
err = -EINVAL;
|
|
goto err_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;
|
|
}
|
|
|
|
err = misc_register(&loop_misc);
|
|
if (err < 0)
|
|
goto err_out;
|
|
|
|
|
|
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);
|
|
err_out:
|
|
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
|