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2291 lines
58 KiB
2291 lines
58 KiB
/* |
|
* linux/drivers/block/loop.c |
|
* |
|
* Written by Theodore Ts'o, 3/29/93 |
|
* |
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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 - [email protected] Mar 20, 1997 |
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* |
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* Added devfs support - Richard Gooch <[email protected]> 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, [email protected] |
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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 <[email protected]> 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, <[email protected]>, 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 <[email protected]>, Nov 2000 |
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* |
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* Support up to 256 loop devices |
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* Heinz Mauelshagen <[email protected]>, 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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|
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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/pagemap.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> |
|
#include <linux/writeback.h> |
|
#include <linux/completion.h> |
|
#include <linux/highmem.h> |
|
#include <linux/splice.h> |
|
#include <linux/sysfs.h> |
|
#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 <linux/ioprio.h> |
|
#include <linux/blk-cgroup.h> |
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#include <linux/sched/mm.h> |
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#include <linux/statfs.h> |
|
|
|
#include "loop.h" |
|
|
|
#include <linux/uaccess.h> |
|
|
|
#define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ) |
|
|
|
static DEFINE_IDR(loop_index_idr); |
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static DEFINE_MUTEX(loop_ctl_mutex); |
|
static DEFINE_MUTEX(loop_validate_mutex); |
|
|
|
/** |
|
* loop_global_lock_killable() - take locks for safe loop_validate_file() test |
|
* |
|
* @lo: struct loop_device |
|
* @global: true if @lo is about to bind another "struct loop_device", false otherwise |
|
* |
|
* Returns 0 on success, -EINTR otherwise. |
|
* |
|
* Since loop_validate_file() traverses on other "struct loop_device" if |
|
* is_loop_device() is true, we need a global lock for serializing concurrent |
|
* loop_configure()/loop_change_fd()/__loop_clr_fd() calls. |
|
*/ |
|
static int loop_global_lock_killable(struct loop_device *lo, bool global) |
|
{ |
|
int err; |
|
|
|
if (global) { |
|
err = mutex_lock_killable(&loop_validate_mutex); |
|
if (err) |
|
return err; |
|
} |
|
err = mutex_lock_killable(&lo->lo_mutex); |
|
if (err && global) |
|
mutex_unlock(&loop_validate_mutex); |
|
return err; |
|
} |
|
|
|
/** |
|
* loop_global_unlock() - release locks taken by loop_global_lock_killable() |
|
* |
|
* @lo: struct loop_device |
|
* @global: true if @lo was about to bind another "struct loop_device", false otherwise |
|
*/ |
|
static void loop_global_unlock(struct loop_device *lo, bool global) |
|
{ |
|
mutex_unlock(&lo->lo_mutex); |
|
if (global) |
|
mutex_unlock(&loop_validate_mutex); |
|
} |
|
|
|
static int max_part; |
|
static int part_shift; |
|
|
|
static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) |
|
{ |
|
loff_t loopsize; |
|
|
|
/* Compute loopsize in bytes */ |
|
loopsize = i_size_read(file->f_mapping->host); |
|
if (offset > 0) |
|
loopsize -= offset; |
|
/* offset is beyond i_size, weird but possible */ |
|
if (loopsize < 0) |
|
return 0; |
|
|
|
if (sizelimit > 0 && sizelimit < loopsize) |
|
loopsize = sizelimit; |
|
/* |
|
* Unfortunately, if we want to do I/O on the device, |
|
* the number of 512-byte sectors has to fit into a sector_t. |
|
*/ |
|
return loopsize >> 9; |
|
} |
|
|
|
static loff_t get_loop_size(struct loop_device *lo, struct file *file) |
|
{ |
|
return get_size(lo->lo_offset, lo->lo_sizelimit, file); |
|
} |
|
|
|
static void __loop_update_dio(struct loop_device *lo, bool dio) |
|
{ |
|
struct file *file = lo->lo_backing_file; |
|
struct address_space *mapping = file->f_mapping; |
|
struct inode *inode = mapping->host; |
|
unsigned short sb_bsize = 0; |
|
unsigned dio_align = 0; |
|
bool use_dio; |
|
|
|
if (inode->i_sb->s_bdev) { |
|
sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev); |
|
dio_align = sb_bsize - 1; |
|
} |
|
|
|
/* |
|
* We support direct I/O only if lo_offset is aligned with the |
|
* logical I/O size of backing device, and the logical block |
|
* size of loop is bigger than the backing device's. |
|
* |
|
* TODO: the above condition may be loosed in the future, and |
|
* direct I/O may be switched runtime at that time because most |
|
* of requests in sane applications should be PAGE_SIZE aligned |
|
*/ |
|
if (dio) { |
|
if (queue_logical_block_size(lo->lo_queue) >= sb_bsize && |
|
!(lo->lo_offset & dio_align) && |
|
mapping->a_ops->direct_IO) |
|
use_dio = true; |
|
else |
|
use_dio = false; |
|
} else { |
|
use_dio = false; |
|
} |
|
|
|
if (lo->use_dio == use_dio) |
|
return; |
|
|
|
/* flush dirty pages before changing direct IO */ |
|
vfs_fsync(file, 0); |
|
|
|
/* |
|
* The flag of LO_FLAGS_DIRECT_IO is handled similarly with |
|
* LO_FLAGS_READ_ONLY, both are set from kernel, and losetup |
|
* will get updated by ioctl(LOOP_GET_STATUS) |
|
*/ |
|
if (lo->lo_state == Lo_bound) |
|
blk_mq_freeze_queue(lo->lo_queue); |
|
lo->use_dio = use_dio; |
|
if (use_dio) { |
|
blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
|
lo->lo_flags |= LO_FLAGS_DIRECT_IO; |
|
} else { |
|
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue); |
|
lo->lo_flags &= ~LO_FLAGS_DIRECT_IO; |
|
} |
|
if (lo->lo_state == Lo_bound) |
|
blk_mq_unfreeze_queue(lo->lo_queue); |
|
} |
|
|
|
/** |
|
* loop_set_size() - sets device size and notifies userspace |
|
* @lo: struct loop_device to set the size for |
|
* @size: new size of the loop device |
|
* |
|
* Callers must validate that the size passed into this function fits into |
|
* a sector_t, eg using loop_validate_size() |
|
*/ |
|
static void loop_set_size(struct loop_device *lo, loff_t size) |
|
{ |
|
if (!set_capacity_and_notify(lo->lo_disk, size)) |
|
kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); |
|
} |
|
|
|
static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) |
|
{ |
|
struct iov_iter i; |
|
ssize_t bw; |
|
|
|
iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len); |
|
|
|
file_start_write(file); |
|
bw = vfs_iter_write(file, &i, ppos, 0); |
|
file_end_write(file); |
|
|
|
if (likely(bw == bvec->bv_len)) |
|
return 0; |
|
|
|
printk_ratelimited(KERN_ERR |
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"loop: Write error at byte offset %llu, length %i.\n", |
|
(unsigned long long)*ppos, bvec->bv_len); |
|
if (bw >= 0) |
|
bw = -EIO; |
|
return bw; |
|
} |
|
|
|
static int lo_write_simple(struct loop_device *lo, struct request *rq, |
|
loff_t pos) |
|
{ |
|
struct bio_vec bvec; |
|
struct req_iterator iter; |
|
int ret = 0; |
|
|
|
rq_for_each_segment(bvec, rq, iter) { |
|
ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos); |
|
if (ret < 0) |
|
break; |
|
cond_resched(); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
static int lo_read_simple(struct loop_device *lo, struct request *rq, |
|
loff_t pos) |
|
{ |
|
struct bio_vec bvec; |
|
struct req_iterator iter; |
|
struct iov_iter i; |
|
ssize_t len; |
|
|
|
rq_for_each_segment(bvec, rq, iter) { |
|
iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len); |
|
len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); |
|
if (len < 0) |
|
return len; |
|
|
|
flush_dcache_page(bvec.bv_page); |
|
|
|
if (len != bvec.bv_len) { |
|
struct bio *bio; |
|
|
|
__rq_for_each_bio(bio, rq) |
|
zero_fill_bio(bio); |
|
break; |
|
} |
|
cond_resched(); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos, |
|
int mode) |
|
{ |
|
/* |
|
* We use fallocate to manipulate the space mappings used by the image |
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* a.k.a. discard/zerorange. |
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*/ |
|
struct file *file = lo->lo_backing_file; |
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struct request_queue *q = lo->lo_queue; |
|
int ret; |
|
|
|
mode |= FALLOC_FL_KEEP_SIZE; |
|
|
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if (!blk_queue_discard(q)) { |
|
ret = -EOPNOTSUPP; |
|
goto out; |
|
} |
|
|
|
ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); |
|
if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) |
|
ret = -EIO; |
|
out: |
|
return ret; |
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} |
|
|
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static int lo_req_flush(struct loop_device *lo, struct request *rq) |
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{ |
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struct file *file = lo->lo_backing_file; |
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int ret = vfs_fsync(file, 0); |
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if (unlikely(ret && ret != -EINVAL)) |
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ret = -EIO; |
|
|
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return ret; |
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} |
|
|
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static void lo_complete_rq(struct request *rq) |
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{ |
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struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); |
|
blk_status_t ret = BLK_STS_OK; |
|
|
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if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || |
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req_op(rq) != REQ_OP_READ) { |
|
if (cmd->ret < 0) |
|
ret = errno_to_blk_status(cmd->ret); |
|
goto end_io; |
|
} |
|
|
|
/* |
|
* Short READ - if we got some data, advance our request and |
|
* retry it. If we got no data, end the rest with EIO. |
|
*/ |
|
if (cmd->ret) { |
|
blk_update_request(rq, BLK_STS_OK, cmd->ret); |
|
cmd->ret = 0; |
|
blk_mq_requeue_request(rq, true); |
|
} else { |
|
if (cmd->use_aio) { |
|
struct bio *bio = rq->bio; |
|
|
|
while (bio) { |
|
zero_fill_bio(bio); |
|
bio = bio->bi_next; |
|
} |
|
} |
|
ret = BLK_STS_IOERR; |
|
end_io: |
|
blk_mq_end_request(rq, ret); |
|
} |
|
} |
|
|
|
static void lo_rw_aio_do_completion(struct loop_cmd *cmd) |
|
{ |
|
struct request *rq = blk_mq_rq_from_pdu(cmd); |
|
|
|
if (!atomic_dec_and_test(&cmd->ref)) |
|
return; |
|
kfree(cmd->bvec); |
|
cmd->bvec = NULL; |
|
if (likely(!blk_should_fake_timeout(rq->q))) |
|
blk_mq_complete_request(rq); |
|
} |
|
|
|
static void lo_rw_aio_complete(struct kiocb *iocb, long ret) |
|
{ |
|
struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); |
|
|
|
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 req_iterator rq_iter; |
|
struct bio_vec *bvec; |
|
struct request *rq = blk_mq_rq_from_pdu(cmd); |
|
struct bio *bio = rq->bio; |
|
struct file *file = lo->lo_backing_file; |
|
struct bio_vec tmp; |
|
unsigned int offset; |
|
int nr_bvec = 0; |
|
int ret; |
|
|
|
rq_for_each_bvec(tmp, rq, rq_iter) |
|
nr_bvec++; |
|
|
|
if (rq->bio != rq->biotail) { |
|
|
|
bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), |
|
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_bvec |
|
* API will take care of all details for us. |
|
*/ |
|
rq_for_each_bvec(tmp, rq, 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); |
|
} |
|
atomic_set(&cmd->ref, 2); |
|
|
|
iov_iter_bvec(&iter, rw, bvec, nr_bvec, 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; |
|
cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); |
|
|
|
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); |
|
|
|
if (ret != -EIOCBQUEUED) |
|
lo_rw_aio_complete(&cmd->iocb, ret); |
|
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_WRITE_ZEROES: |
|
/* |
|
* If the caller doesn't want deallocation, call zeroout to |
|
* write zeroes the range. Otherwise, punch them out. |
|
*/ |
|
return lo_fallocate(lo, rq, pos, |
|
(rq->cmd_flags & REQ_NOUNMAP) ? |
|
FALLOC_FL_ZERO_RANGE : |
|
FALLOC_FL_PUNCH_HOLE); |
|
case REQ_OP_DISCARD: |
|
return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE); |
|
case REQ_OP_WRITE: |
|
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 (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; |
|
} |
|
} |
|
|
|
static inline void loop_update_dio(struct loop_device *lo) |
|
{ |
|
__loop_update_dio(lo, (lo->lo_backing_file->f_flags & O_DIRECT) | |
|
lo->use_dio); |
|
} |
|
|
|
static void loop_reread_partitions(struct loop_device *lo) |
|
{ |
|
int rc; |
|
|
|
mutex_lock(&lo->lo_disk->open_mutex); |
|
rc = bdev_disk_changed(lo->lo_disk, false); |
|
mutex_unlock(&lo->lo_disk->open_mutex); |
|
if (rc) |
|
pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", |
|
__func__, lo->lo_number, lo->lo_file_name, rc); |
|
} |
|
|
|
static inline int is_loop_device(struct file *file) |
|
{ |
|
struct inode *i = file->f_mapping->host; |
|
|
|
return i && S_ISBLK(i->i_mode) && imajor(i) == LOOP_MAJOR; |
|
} |
|
|
|
static int loop_validate_file(struct file *file, struct block_device *bdev) |
|
{ |
|
struct inode *inode = file->f_mapping->host; |
|
struct file *f = file; |
|
|
|
/* Avoid recursion */ |
|
while (is_loop_device(f)) { |
|
struct loop_device *l; |
|
|
|
lockdep_assert_held(&loop_validate_mutex); |
|
if (f->f_mapping->host->i_rdev == bdev->bd_dev) |
|
return -EBADF; |
|
|
|
l = I_BDEV(f->f_mapping->host)->bd_disk->private_data; |
|
if (l->lo_state != Lo_bound) |
|
return -EINVAL; |
|
/* Order wrt setting lo->lo_backing_file in loop_configure(). */ |
|
rmb(); |
|
f = l->lo_backing_file; |
|
} |
|
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) |
|
return -EINVAL; |
|
return 0; |
|
} |
|
|
|
/* |
|
* 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 = fget(arg); |
|
struct file *old_file; |
|
int error; |
|
bool partscan; |
|
bool is_loop; |
|
|
|
if (!file) |
|
return -EBADF; |
|
is_loop = is_loop_device(file); |
|
error = loop_global_lock_killable(lo, is_loop); |
|
if (error) |
|
goto out_putf; |
|
error = -ENXIO; |
|
if (lo->lo_state != Lo_bound) |
|
goto out_err; |
|
|
|
/* the loop device has to be read-only */ |
|
error = -EINVAL; |
|
if (!(lo->lo_flags & LO_FLAGS_READ_ONLY)) |
|
goto out_err; |
|
|
|
error = loop_validate_file(file, bdev); |
|
if (error) |
|
goto out_err; |
|
|
|
old_file = lo->lo_backing_file; |
|
|
|
error = -EINVAL; |
|
|
|
/* 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_err; |
|
|
|
/* and ... switch */ |
|
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); |
|
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); |
|
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; |
|
loop_global_unlock(lo, is_loop); |
|
|
|
/* |
|
* Flush loop_validate_file() before fput(), for l->lo_backing_file |
|
* might be pointing at old_file which might be the last reference. |
|
*/ |
|
if (!is_loop) { |
|
mutex_lock(&loop_validate_mutex); |
|
mutex_unlock(&loop_validate_mutex); |
|
} |
|
/* |
|
* We must drop file reference outside of lo_mutex as dropping |
|
* the file ref can take open_mutex which creates circular locking |
|
* dependency. |
|
*/ |
|
fput(old_file); |
|
if (partscan) |
|
loop_reread_partitions(lo); |
|
return 0; |
|
|
|
out_err: |
|
loop_global_unlock(lo, is_loop); |
|
out_putf: |
|
fput(file); |
|
return error; |
|
} |
|
|
|
/* 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, 0444, 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 void loop_sysfs_init(struct loop_device *lo) |
|
{ |
|
lo->sysfs_inited = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj, |
|
&loop_attribute_group); |
|
} |
|
|
|
static void loop_sysfs_exit(struct loop_device *lo) |
|
{ |
|
if (lo->sysfs_inited) |
|
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; |
|
u32 granularity, max_discard_sectors; |
|
|
|
/* |
|
* If the backing device is a block device, mirror its zeroing |
|
* capability. Set the discard sectors to the block device's zeroing |
|
* capabilities because loop discards result in blkdev_issue_zeroout(), |
|
* not blkdev_issue_discard(). This maintains consistent behavior with |
|
* file-backed loop devices: discarded regions read back as zero. |
|
*/ |
|
if (S_ISBLK(inode->i_mode)) { |
|
struct request_queue *backingq = bdev_get_queue(I_BDEV(inode)); |
|
|
|
max_discard_sectors = backingq->limits.max_write_zeroes_sectors; |
|
granularity = backingq->limits.discard_granularity ?: |
|
queue_physical_block_size(backingq); |
|
|
|
/* |
|
* We use punch hole to reclaim the free space used by the |
|
* image a.k.a. discard. |
|
*/ |
|
} else if (!file->f_op->fallocate) { |
|
max_discard_sectors = 0; |
|
granularity = 0; |
|
|
|
} else { |
|
struct kstatfs sbuf; |
|
|
|
max_discard_sectors = UINT_MAX >> 9; |
|
if (!vfs_statfs(&file->f_path, &sbuf)) |
|
granularity = sbuf.f_bsize; |
|
else |
|
max_discard_sectors = 0; |
|
} |
|
|
|
if (max_discard_sectors) { |
|
q->limits.discard_granularity = granularity; |
|
blk_queue_max_discard_sectors(q, max_discard_sectors); |
|
blk_queue_max_write_zeroes_sectors(q, max_discard_sectors); |
|
blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); |
|
} else { |
|
q->limits.discard_granularity = 0; |
|
blk_queue_max_discard_sectors(q, 0); |
|
blk_queue_max_write_zeroes_sectors(q, 0); |
|
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); |
|
} |
|
q->limits.discard_alignment = 0; |
|
} |
|
|
|
struct loop_worker { |
|
struct rb_node rb_node; |
|
struct work_struct work; |
|
struct list_head cmd_list; |
|
struct list_head idle_list; |
|
struct loop_device *lo; |
|
struct cgroup_subsys_state *blkcg_css; |
|
unsigned long last_ran_at; |
|
}; |
|
|
|
static void loop_workfn(struct work_struct *work); |
|
static void loop_rootcg_workfn(struct work_struct *work); |
|
static void loop_free_idle_workers(struct timer_list *timer); |
|
|
|
#ifdef CONFIG_BLK_CGROUP |
|
static inline int queue_on_root_worker(struct cgroup_subsys_state *css) |
|
{ |
|
return !css || css == blkcg_root_css; |
|
} |
|
#else |
|
static inline int queue_on_root_worker(struct cgroup_subsys_state *css) |
|
{ |
|
return !css; |
|
} |
|
#endif |
|
|
|
static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) |
|
{ |
|
struct rb_node **node, *parent = NULL; |
|
struct loop_worker *cur_worker, *worker = NULL; |
|
struct work_struct *work; |
|
struct list_head *cmd_list; |
|
|
|
spin_lock_irq(&lo->lo_work_lock); |
|
|
|
if (queue_on_root_worker(cmd->blkcg_css)) |
|
goto queue_work; |
|
|
|
node = &lo->worker_tree.rb_node; |
|
|
|
while (*node) { |
|
parent = *node; |
|
cur_worker = container_of(*node, struct loop_worker, rb_node); |
|
if (cur_worker->blkcg_css == cmd->blkcg_css) { |
|
worker = cur_worker; |
|
break; |
|
} else if ((long)cur_worker->blkcg_css < (long)cmd->blkcg_css) { |
|
node = &(*node)->rb_left; |
|
} else { |
|
node = &(*node)->rb_right; |
|
} |
|
} |
|
if (worker) |
|
goto queue_work; |
|
|
|
worker = kzalloc(sizeof(struct loop_worker), GFP_NOWAIT | __GFP_NOWARN); |
|
/* |
|
* In the event we cannot allocate a worker, just queue on the |
|
* rootcg worker and issue the I/O as the rootcg |
|
*/ |
|
if (!worker) { |
|
cmd->blkcg_css = NULL; |
|
if (cmd->memcg_css) |
|
css_put(cmd->memcg_css); |
|
cmd->memcg_css = NULL; |
|
goto queue_work; |
|
} |
|
|
|
worker->blkcg_css = cmd->blkcg_css; |
|
css_get(worker->blkcg_css); |
|
INIT_WORK(&worker->work, loop_workfn); |
|
INIT_LIST_HEAD(&worker->cmd_list); |
|
INIT_LIST_HEAD(&worker->idle_list); |
|
worker->lo = lo; |
|
rb_link_node(&worker->rb_node, parent, node); |
|
rb_insert_color(&worker->rb_node, &lo->worker_tree); |
|
queue_work: |
|
if (worker) { |
|
/* |
|
* We need to remove from the idle list here while |
|
* holding the lock so that the idle timer doesn't |
|
* free the worker |
|
*/ |
|
if (!list_empty(&worker->idle_list)) |
|
list_del_init(&worker->idle_list); |
|
work = &worker->work; |
|
cmd_list = &worker->cmd_list; |
|
} else { |
|
work = &lo->rootcg_work; |
|
cmd_list = &lo->rootcg_cmd_list; |
|
} |
|
list_add_tail(&cmd->list_entry, cmd_list); |
|
queue_work(lo->workqueue, work); |
|
spin_unlock_irq(&lo->lo_work_lock); |
|
} |
|
|
|
static void loop_update_rotational(struct loop_device *lo) |
|
{ |
|
struct file *file = lo->lo_backing_file; |
|
struct inode *file_inode = file->f_mapping->host; |
|
struct block_device *file_bdev = file_inode->i_sb->s_bdev; |
|
struct request_queue *q = lo->lo_queue; |
|
bool nonrot = true; |
|
|
|
/* not all filesystems (e.g. tmpfs) have a sb->s_bdev */ |
|
if (file_bdev) |
|
nonrot = blk_queue_nonrot(bdev_get_queue(file_bdev)); |
|
|
|
if (nonrot) |
|
blk_queue_flag_set(QUEUE_FLAG_NONROT, q); |
|
else |
|
blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); |
|
} |
|
|
|
/** |
|
* loop_set_status_from_info - configure device from loop_info |
|
* @lo: struct loop_device to configure |
|
* @info: struct loop_info64 to configure the device with |
|
* |
|
* Configures the loop device parameters according to the passed |
|
* in loop_info64 configuration. |
|
*/ |
|
static int |
|
loop_set_status_from_info(struct loop_device *lo, |
|
const struct loop_info64 *info) |
|
{ |
|
if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) |
|
return -EINVAL; |
|
|
|
switch (info->lo_encrypt_type) { |
|
case LO_CRYPT_NONE: |
|
break; |
|
case LO_CRYPT_XOR: |
|
pr_warn("support for the xor transformation has been removed.\n"); |
|
return -EINVAL; |
|
case LO_CRYPT_CRYPTOAPI: |
|
pr_warn("support for cryptoloop has been removed. Use dm-crypt instead.\n"); |
|
return -EINVAL; |
|
default: |
|
return -EINVAL; |
|
} |
|
|
|
lo->lo_offset = info->lo_offset; |
|
lo->lo_sizelimit = info->lo_sizelimit; |
|
memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); |
|
lo->lo_file_name[LO_NAME_SIZE-1] = 0; |
|
lo->lo_flags = info->lo_flags; |
|
return 0; |
|
} |
|
|
|
static int loop_configure(struct loop_device *lo, fmode_t mode, |
|
struct block_device *bdev, |
|
const struct loop_config *config) |
|
{ |
|
struct file *file = fget(config->fd); |
|
struct inode *inode; |
|
struct address_space *mapping; |
|
int error; |
|
loff_t size; |
|
bool partscan; |
|
unsigned short bsize; |
|
bool is_loop; |
|
|
|
if (!file) |
|
return -EBADF; |
|
is_loop = is_loop_device(file); |
|
|
|
/* This is safe, since we have a reference from open(). */ |
|
__module_get(THIS_MODULE); |
|
|
|
/* |
|
* If we don't hold exclusive handle for the device, upgrade to it |
|
* here to avoid changing device under exclusive owner. |
|
*/ |
|
if (!(mode & FMODE_EXCL)) { |
|
error = bd_prepare_to_claim(bdev, loop_configure); |
|
if (error) |
|
goto out_putf; |
|
} |
|
|
|
error = loop_global_lock_killable(lo, is_loop); |
|
if (error) |
|
goto out_bdev; |
|
|
|
error = -EBUSY; |
|
if (lo->lo_state != Lo_unbound) |
|
goto out_unlock; |
|
|
|
error = loop_validate_file(file, bdev); |
|
if (error) |
|
goto out_unlock; |
|
|
|
mapping = file->f_mapping; |
|
inode = mapping->host; |
|
|
|
if ((config->info.lo_flags & ~LOOP_CONFIGURE_SETTABLE_FLAGS) != 0) { |
|
error = -EINVAL; |
|
goto out_unlock; |
|
} |
|
|
|
if (config->block_size) { |
|
error = blk_validate_block_size(config->block_size); |
|
if (error) |
|
goto out_unlock; |
|
} |
|
|
|
error = loop_set_status_from_info(lo, &config->info); |
|
if (error) |
|
goto out_unlock; |
|
|
|
if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) || |
|
!file->f_op->write_iter) |
|
lo->lo_flags |= LO_FLAGS_READ_ONLY; |
|
|
|
lo->workqueue = alloc_workqueue("loop%d", |
|
WQ_UNBOUND | WQ_FREEZABLE, |
|
0, |
|
lo->lo_number); |
|
if (!lo->workqueue) { |
|
error = -ENOMEM; |
|
goto out_unlock; |
|
} |
|
|
|
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); |
|
set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0); |
|
|
|
INIT_WORK(&lo->rootcg_work, loop_rootcg_workfn); |
|
INIT_LIST_HEAD(&lo->rootcg_cmd_list); |
|
INIT_LIST_HEAD(&lo->idle_worker_list); |
|
lo->worker_tree = RB_ROOT; |
|
timer_setup(&lo->timer, loop_free_idle_workers, |
|
TIMER_DEFERRABLE); |
|
lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO; |
|
lo->lo_device = bdev; |
|
lo->lo_backing_file = file; |
|
lo->old_gfp_mask = mapping_gfp_mask(mapping); |
|
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); |
|
|
|
if (!(lo->lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) |
|
blk_queue_write_cache(lo->lo_queue, true, false); |
|
|
|
if (config->block_size) |
|
bsize = config->block_size; |
|
else if ((lo->lo_backing_file->f_flags & O_DIRECT) && inode->i_sb->s_bdev) |
|
/* In case of direct I/O, match underlying block size */ |
|
bsize = bdev_logical_block_size(inode->i_sb->s_bdev); |
|
else |
|
bsize = 512; |
|
|
|
blk_queue_logical_block_size(lo->lo_queue, bsize); |
|
blk_queue_physical_block_size(lo->lo_queue, bsize); |
|
blk_queue_io_min(lo->lo_queue, bsize); |
|
|
|
loop_config_discard(lo); |
|
loop_update_rotational(lo); |
|
loop_update_dio(lo); |
|
loop_sysfs_init(lo); |
|
|
|
size = get_loop_size(lo, file); |
|
loop_set_size(lo, size); |
|
|
|
/* Order wrt reading lo_state in loop_validate_file(). */ |
|
wmb(); |
|
|
|
lo->lo_state = Lo_bound; |
|
if (part_shift) |
|
lo->lo_flags |= LO_FLAGS_PARTSCAN; |
|
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN; |
|
if (partscan) |
|
lo->lo_disk->flags &= ~GENHD_FL_NO_PART; |
|
|
|
loop_global_unlock(lo, is_loop); |
|
if (partscan) |
|
loop_reread_partitions(lo); |
|
if (!(mode & FMODE_EXCL)) |
|
bd_abort_claiming(bdev, loop_configure); |
|
return 0; |
|
|
|
out_unlock: |
|
loop_global_unlock(lo, is_loop); |
|
out_bdev: |
|
if (!(mode & FMODE_EXCL)) |
|
bd_abort_claiming(bdev, loop_configure); |
|
out_putf: |
|
fput(file); |
|
/* This is safe: open() is still holding a reference. */ |
|
module_put(THIS_MODULE); |
|
return error; |
|
} |
|
|
|
static void __loop_clr_fd(struct loop_device *lo, bool release) |
|
{ |
|
struct file *filp; |
|
gfp_t gfp = lo->old_gfp_mask; |
|
struct loop_worker *pos, *worker; |
|
|
|
/* |
|
* Flush loop_configure() and loop_change_fd(). It is acceptable for |
|
* loop_validate_file() to succeed, for actual clear operation has not |
|
* started yet. |
|
*/ |
|
mutex_lock(&loop_validate_mutex); |
|
mutex_unlock(&loop_validate_mutex); |
|
/* |
|
* loop_validate_file() now fails because l->lo_state != Lo_bound |
|
* became visible. |
|
*/ |
|
|
|
/* |
|
* Since this function is called upon "ioctl(LOOP_CLR_FD)" xor "close() |
|
* after ioctl(LOOP_CLR_FD)", it is a sign of something going wrong if |
|
* lo->lo_state has changed while waiting for lo->lo_mutex. |
|
*/ |
|
mutex_lock(&lo->lo_mutex); |
|
BUG_ON(lo->lo_state != Lo_rundown); |
|
mutex_unlock(&lo->lo_mutex); |
|
|
|
if (test_bit(QUEUE_FLAG_WC, &lo->lo_queue->queue_flags)) |
|
blk_queue_write_cache(lo->lo_queue, false, false); |
|
|
|
/* freeze request queue during the transition */ |
|
blk_mq_freeze_queue(lo->lo_queue); |
|
|
|
destroy_workqueue(lo->workqueue); |
|
spin_lock_irq(&lo->lo_work_lock); |
|
list_for_each_entry_safe(worker, pos, &lo->idle_worker_list, |
|
idle_list) { |
|
list_del(&worker->idle_list); |
|
rb_erase(&worker->rb_node, &lo->worker_tree); |
|
css_put(worker->blkcg_css); |
|
kfree(worker); |
|
} |
|
spin_unlock_irq(&lo->lo_work_lock); |
|
del_timer_sync(&lo->timer); |
|
|
|
spin_lock_irq(&lo->lo_lock); |
|
filp = lo->lo_backing_file; |
|
lo->lo_backing_file = NULL; |
|
spin_unlock_irq(&lo->lo_lock); |
|
|
|
lo->lo_device = NULL; |
|
lo->lo_offset = 0; |
|
lo->lo_sizelimit = 0; |
|
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); |
|
invalidate_disk(lo->lo_disk); |
|
loop_sysfs_exit(lo); |
|
/* let user-space know about this change */ |
|
kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE); |
|
mapping_set_gfp_mask(filp->f_mapping, gfp); |
|
/* This is safe: open() is still holding a reference. */ |
|
module_put(THIS_MODULE); |
|
blk_mq_unfreeze_queue(lo->lo_queue); |
|
|
|
disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); |
|
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN) { |
|
int err; |
|
|
|
/* |
|
* open_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 (!release) |
|
mutex_lock(&lo->lo_disk->open_mutex); |
|
err = bdev_disk_changed(lo->lo_disk, false); |
|
if (!release) |
|
mutex_unlock(&lo->lo_disk->open_mutex); |
|
if (err) |
|
pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", |
|
__func__, lo->lo_number, err); |
|
/* Device is gone, no point in returning error */ |
|
} |
|
|
|
/* |
|
* lo->lo_state is set to Lo_unbound here after above partscan has |
|
* finished. There cannot be anybody else entering __loop_clr_fd() as |
|
* Lo_rundown state protects us from all the other places trying to |
|
* change the 'lo' device. |
|
*/ |
|
lo->lo_flags = 0; |
|
if (!part_shift) |
|
lo->lo_disk->flags |= GENHD_FL_NO_PART; |
|
mutex_lock(&lo->lo_mutex); |
|
lo->lo_state = Lo_unbound; |
|
mutex_unlock(&lo->lo_mutex); |
|
|
|
/* |
|
* Need not hold lo_mutex to fput backing file. Calling fput holding |
|
* lo_mutex triggers a circular lock dependency possibility warning as |
|
* fput can take open_mutex which is usually taken before lo_mutex. |
|
*/ |
|
fput(filp); |
|
} |
|
|
|
static int loop_clr_fd(struct loop_device *lo) |
|
{ |
|
int err; |
|
|
|
err = mutex_lock_killable(&lo->lo_mutex); |
|
if (err) |
|
return err; |
|
if (lo->lo_state != Lo_bound) { |
|
mutex_unlock(&lo->lo_mutex); |
|
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_mutex); |
|
return 0; |
|
} |
|
lo->lo_state = Lo_rundown; |
|
mutex_unlock(&lo->lo_mutex); |
|
|
|
__loop_clr_fd(lo, false); |
|
return 0; |
|
} |
|
|
|
static int |
|
loop_set_status(struct loop_device *lo, const struct loop_info64 *info) |
|
{ |
|
int err; |
|
int prev_lo_flags; |
|
bool partscan = false; |
|
bool size_changed = false; |
|
|
|
err = mutex_lock_killable(&lo->lo_mutex); |
|
if (err) |
|
return err; |
|
if (lo->lo_state != Lo_bound) { |
|
err = -ENXIO; |
|
goto out_unlock; |
|
} |
|
|
|
if (lo->lo_offset != info->lo_offset || |
|
lo->lo_sizelimit != info->lo_sizelimit) { |
|
size_changed = true; |
|
sync_blockdev(lo->lo_device); |
|
invalidate_bdev(lo->lo_device); |
|
} |
|
|
|
/* I/O need to be drained during transfer transition */ |
|
blk_mq_freeze_queue(lo->lo_queue); |
|
|
|
if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) { |
|
/* If any pages were dirtied after invalidate_bdev(), try again */ |
|
err = -EAGAIN; |
|
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", |
|
__func__, lo->lo_number, lo->lo_file_name, |
|
lo->lo_device->bd_inode->i_mapping->nrpages); |
|
goto out_unfreeze; |
|
} |
|
|
|
prev_lo_flags = lo->lo_flags; |
|
|
|
err = loop_set_status_from_info(lo, info); |
|
if (err) |
|
goto out_unfreeze; |
|
|
|
/* Mask out flags that can't be set using LOOP_SET_STATUS. */ |
|
lo->lo_flags &= LOOP_SET_STATUS_SETTABLE_FLAGS; |
|
/* For those flags, use the previous values instead */ |
|
lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_SETTABLE_FLAGS; |
|
/* For flags that can't be cleared, use previous values too */ |
|
lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_CLEARABLE_FLAGS; |
|
|
|
if (size_changed) { |
|
loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit, |
|
lo->lo_backing_file); |
|
loop_set_size(lo, new_size); |
|
} |
|
|
|
loop_config_discard(lo); |
|
|
|
/* update dio if lo_offset or transfer is changed */ |
|
__loop_update_dio(lo, lo->use_dio); |
|
|
|
out_unfreeze: |
|
blk_mq_unfreeze_queue(lo->lo_queue); |
|
|
|
if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) && |
|
!(prev_lo_flags & LO_FLAGS_PARTSCAN)) { |
|
lo->lo_disk->flags &= ~GENHD_FL_NO_PART; |
|
partscan = true; |
|
} |
|
out_unlock: |
|
mutex_unlock(&lo->lo_mutex); |
|
if (partscan) |
|
loop_reread_partitions(lo); |
|
|
|
return err; |
|
} |
|
|
|
static int |
|
loop_get_status(struct loop_device *lo, struct loop_info64 *info) |
|
{ |
|
struct path path; |
|
struct kstat stat; |
|
int ret; |
|
|
|
ret = mutex_lock_killable(&lo->lo_mutex); |
|
if (ret) |
|
return ret; |
|
if (lo->lo_state != Lo_bound) { |
|
mutex_unlock(&lo->lo_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); |
|
|
|
/* Drop lo_mutex while we call into the filesystem. */ |
|
path = lo->lo_backing_file->f_path; |
|
path_get(&path); |
|
mutex_unlock(&lo->lo_mutex); |
|
ret = vfs_getattr(&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); |
|
} |
|
path_put(&path); |
|
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_flags = info->lo_flags; |
|
memcpy(info64->lo_file_name, info->lo_name, LO_NAME_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_flags = info64->lo_flags; |
|
memcpy(info->lo_name, info64->lo_file_name, LO_NAME_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) |
|
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) |
|
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) |
|
{ |
|
loff_t size; |
|
|
|
if (unlikely(lo->lo_state != Lo_bound)) |
|
return -ENXIO; |
|
|
|
size = get_loop_size(lo, lo->lo_backing_file); |
|
loop_set_size(lo, size); |
|
|
|
return 0; |
|
} |
|
|
|
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) |
|
{ |
|
int err = 0; |
|
|
|
if (lo->lo_state != Lo_bound) |
|
return -ENXIO; |
|
|
|
err = blk_validate_block_size(arg); |
|
if (err) |
|
return err; |
|
|
|
if (lo->lo_queue->limits.logical_block_size == arg) |
|
return 0; |
|
|
|
sync_blockdev(lo->lo_device); |
|
invalidate_bdev(lo->lo_device); |
|
|
|
blk_mq_freeze_queue(lo->lo_queue); |
|
|
|
/* invalidate_bdev should have truncated all the pages */ |
|
if (lo->lo_device->bd_inode->i_mapping->nrpages) { |
|
err = -EAGAIN; |
|
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", |
|
__func__, lo->lo_number, lo->lo_file_name, |
|
lo->lo_device->bd_inode->i_mapping->nrpages); |
|
goto out_unfreeze; |
|
} |
|
|
|
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); |
|
out_unfreeze: |
|
blk_mq_unfreeze_queue(lo->lo_queue); |
|
|
|
return err; |
|
} |
|
|
|
static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd, |
|
unsigned long arg) |
|
{ |
|
int err; |
|
|
|
err = mutex_lock_killable(&lo->lo_mutex); |
|
if (err) |
|
return err; |
|
switch (cmd) { |
|
case LOOP_SET_CAPACITY: |
|
err = loop_set_capacity(lo); |
|
break; |
|
case LOOP_SET_DIRECT_IO: |
|
err = loop_set_dio(lo, arg); |
|
break; |
|
case LOOP_SET_BLOCK_SIZE: |
|
err = loop_set_block_size(lo, arg); |
|
break; |
|
default: |
|
err = -EINVAL; |
|
} |
|
mutex_unlock(&lo->lo_mutex); |
|
return err; |
|
} |
|
|
|
static int lo_ioctl(struct block_device *bdev, fmode_t mode, |
|
unsigned int cmd, unsigned long arg) |
|
{ |
|
struct loop_device *lo = bdev->bd_disk->private_data; |
|
void __user *argp = (void __user *) arg; |
|
int err; |
|
|
|
switch (cmd) { |
|
case LOOP_SET_FD: { |
|
/* |
|
* Legacy case - pass in a zeroed out struct loop_config with |
|
* only the file descriptor set , which corresponds with the |
|
* default parameters we'd have used otherwise. |
|
*/ |
|
struct loop_config config; |
|
|
|
memset(&config, 0, sizeof(config)); |
|
config.fd = arg; |
|
|
|
return loop_configure(lo, mode, bdev, &config); |
|
} |
|
case LOOP_CONFIGURE: { |
|
struct loop_config config; |
|
|
|
if (copy_from_user(&config, argp, sizeof(config))) |
|
return -EFAULT; |
|
|
|
return loop_configure(lo, mode, bdev, &config); |
|
} |
|
case LOOP_CHANGE_FD: |
|
return loop_change_fd(lo, bdev, arg); |
|
case LOOP_CLR_FD: |
|
return loop_clr_fd(lo); |
|
case LOOP_SET_STATUS: |
|
err = -EPERM; |
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { |
|
err = loop_set_status_old(lo, argp); |
|
} |
|
break; |
|
case LOOP_GET_STATUS: |
|
return loop_get_status_old(lo, argp); |
|
case LOOP_SET_STATUS64: |
|
err = -EPERM; |
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) { |
|
err = loop_set_status64(lo, argp); |
|
} |
|
break; |
|
case LOOP_GET_STATUS64: |
|
return loop_get_status64(lo, argp); |
|
case LOOP_SET_CAPACITY: |
|
case LOOP_SET_DIRECT_IO: |
|
case LOOP_SET_BLOCK_SIZE: |
|
if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN)) |
|
return -EPERM; |
|
fallthrough; |
|
default: |
|
err = lo_simple_ioctl(lo, cmd, arg); |
|
break; |
|
} |
|
|
|
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_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_flags = info.lo_flags; |
|
memcpy(info64->lo_file_name, info.lo_name, LO_NAME_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_flags = info64->lo_flags; |
|
memcpy(info.lo_name, info64->lo_file_name, LO_NAME_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; |
|
|
|
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) |
|
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 = loop_set_status_compat(lo, |
|
(const struct compat_loop_info __user *)arg); |
|
break; |
|
case LOOP_GET_STATUS: |
|
err = loop_get_status_compat(lo, |
|
(struct compat_loop_info __user *)arg); |
|
break; |
|
case LOOP_SET_CAPACITY: |
|
case LOOP_CLR_FD: |
|
case LOOP_GET_STATUS64: |
|
case LOOP_SET_STATUS64: |
|
case LOOP_CONFIGURE: |
|
arg = (unsigned long) compat_ptr(arg); |
|
fallthrough; |
|
case LOOP_SET_FD: |
|
case LOOP_CHANGE_FD: |
|
case LOOP_SET_BLOCK_SIZE: |
|
case LOOP_SET_DIRECT_IO: |
|
err = lo_ioctl(bdev, mode, cmd, arg); |
|
break; |
|
default: |
|
err = -ENOIOCTLCMD; |
|
break; |
|
} |
|
return err; |
|
} |
|
#endif |
|
|
|
static int lo_open(struct block_device *bdev, fmode_t mode) |
|
{ |
|
struct loop_device *lo = bdev->bd_disk->private_data; |
|
int err; |
|
|
|
err = mutex_lock_killable(&lo->lo_mutex); |
|
if (err) |
|
return err; |
|
if (lo->lo_state == Lo_deleting) |
|
err = -ENXIO; |
|
else |
|
atomic_inc(&lo->lo_refcnt); |
|
mutex_unlock(&lo->lo_mutex); |
|
return err; |
|
} |
|
|
|
static void lo_release(struct gendisk *disk, fmode_t mode) |
|
{ |
|
struct loop_device *lo = disk->private_data; |
|
|
|
mutex_lock(&lo->lo_mutex); |
|
if (atomic_dec_return(&lo->lo_refcnt)) |
|
goto out_unlock; |
|
|
|
if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { |
|
if (lo->lo_state != Lo_bound) |
|
goto out_unlock; |
|
lo->lo_state = Lo_rundown; |
|
mutex_unlock(&lo->lo_mutex); |
|
/* |
|
* In autoclear mode, stop the loop thread |
|
* and remove configuration after last close. |
|
*/ |
|
__loop_clr_fd(lo, true); |
|
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); |
|
} |
|
|
|
out_unlock: |
|
mutex_unlock(&lo->lo_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, 0444); |
|
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); |
|
module_param(max_part, int, 0444); |
|
MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); |
|
MODULE_LICENSE("GPL"); |
|
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); |
|
|
|
static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, |
|
const struct blk_mq_queue_data *bd) |
|
{ |
|
struct request *rq = bd->rq; |
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); |
|
struct loop_device *lo = rq->q->queuedata; |
|
|
|
blk_mq_start_request(rq); |
|
|
|
if (lo->lo_state != Lo_bound) |
|
return BLK_STS_IOERR; |
|
|
|
switch (req_op(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 */ |
|
cmd->blkcg_css = NULL; |
|
cmd->memcg_css = NULL; |
|
#ifdef CONFIG_BLK_CGROUP |
|
if (rq->bio && rq->bio->bi_blkg) { |
|
cmd->blkcg_css = &bio_blkcg(rq->bio)->css; |
|
#ifdef CONFIG_MEMCG |
|
cmd->memcg_css = |
|
cgroup_get_e_css(cmd->blkcg_css->cgroup, |
|
&memory_cgrp_subsys); |
|
#endif |
|
} |
|
#endif |
|
loop_queue_work(lo, cmd); |
|
|
|
return BLK_STS_OK; |
|
} |
|
|
|
static void loop_handle_cmd(struct loop_cmd *cmd) |
|
{ |
|
struct request *rq = blk_mq_rq_from_pdu(cmd); |
|
const bool write = op_is_write(req_op(rq)); |
|
struct loop_device *lo = rq->q->queuedata; |
|
int ret = 0; |
|
struct mem_cgroup *old_memcg = NULL; |
|
|
|
if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { |
|
ret = -EIO; |
|
goto failed; |
|
} |
|
|
|
if (cmd->blkcg_css) |
|
kthread_associate_blkcg(cmd->blkcg_css); |
|
if (cmd->memcg_css) |
|
old_memcg = set_active_memcg( |
|
mem_cgroup_from_css(cmd->memcg_css)); |
|
|
|
ret = do_req_filebacked(lo, rq); |
|
|
|
if (cmd->blkcg_css) |
|
kthread_associate_blkcg(NULL); |
|
|
|
if (cmd->memcg_css) { |
|
set_active_memcg(old_memcg); |
|
css_put(cmd->memcg_css); |
|
} |
|
failed: |
|
/* complete non-aio request */ |
|
if (!cmd->use_aio || ret) { |
|
if (ret == -EOPNOTSUPP) |
|
cmd->ret = ret; |
|
else |
|
cmd->ret = ret ? -EIO : 0; |
|
if (likely(!blk_should_fake_timeout(rq->q))) |
|
blk_mq_complete_request(rq); |
|
} |
|
} |
|
|
|
static void loop_set_timer(struct loop_device *lo) |
|
{ |
|
timer_reduce(&lo->timer, jiffies + LOOP_IDLE_WORKER_TIMEOUT); |
|
} |
|
|
|
static void loop_process_work(struct loop_worker *worker, |
|
struct list_head *cmd_list, struct loop_device *lo) |
|
{ |
|
int orig_flags = current->flags; |
|
struct loop_cmd *cmd; |
|
|
|
current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; |
|
spin_lock_irq(&lo->lo_work_lock); |
|
while (!list_empty(cmd_list)) { |
|
cmd = container_of( |
|
cmd_list->next, struct loop_cmd, list_entry); |
|
list_del(cmd_list->next); |
|
spin_unlock_irq(&lo->lo_work_lock); |
|
|
|
loop_handle_cmd(cmd); |
|
cond_resched(); |
|
|
|
spin_lock_irq(&lo->lo_work_lock); |
|
} |
|
|
|
/* |
|
* We only add to the idle list if there are no pending cmds |
|
* *and* the worker will not run again which ensures that it |
|
* is safe to free any worker on the idle list |
|
*/ |
|
if (worker && !work_pending(&worker->work)) { |
|
worker->last_ran_at = jiffies; |
|
list_add_tail(&worker->idle_list, &lo->idle_worker_list); |
|
loop_set_timer(lo); |
|
} |
|
spin_unlock_irq(&lo->lo_work_lock); |
|
current->flags = orig_flags; |
|
} |
|
|
|
static void loop_workfn(struct work_struct *work) |
|
{ |
|
struct loop_worker *worker = |
|
container_of(work, struct loop_worker, work); |
|
loop_process_work(worker, &worker->cmd_list, worker->lo); |
|
} |
|
|
|
static void loop_rootcg_workfn(struct work_struct *work) |
|
{ |
|
struct loop_device *lo = |
|
container_of(work, struct loop_device, rootcg_work); |
|
loop_process_work(NULL, &lo->rootcg_cmd_list, lo); |
|
} |
|
|
|
static void loop_free_idle_workers(struct timer_list *timer) |
|
{ |
|
struct loop_device *lo = container_of(timer, struct loop_device, timer); |
|
struct loop_worker *pos, *worker; |
|
|
|
spin_lock_irq(&lo->lo_work_lock); |
|
list_for_each_entry_safe(worker, pos, &lo->idle_worker_list, |
|
idle_list) { |
|
if (time_is_after_jiffies(worker->last_ran_at + |
|
LOOP_IDLE_WORKER_TIMEOUT)) |
|
break; |
|
list_del(&worker->idle_list); |
|
rb_erase(&worker->rb_node, &lo->worker_tree); |
|
css_put(worker->blkcg_css); |
|
kfree(worker); |
|
} |
|
if (!list_empty(&lo->idle_worker_list)) |
|
loop_set_timer(lo); |
|
spin_unlock_irq(&lo->lo_work_lock); |
|
} |
|
|
|
static const struct blk_mq_ops loop_mq_ops = { |
|
.queue_rq = loop_queue_rq, |
|
.complete = lo_complete_rq, |
|
}; |
|
|
|
static int loop_add(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; |
|
|
|
err = mutex_lock_killable(&loop_ctl_mutex); |
|
if (err) |
|
goto out_free_dev; |
|
|
|
/* 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); |
|
} |
|
mutex_unlock(&loop_ctl_mutex); |
|
if (err < 0) |
|
goto out_free_dev; |
|
i = err; |
|
|
|
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_STACKING | |
|
BLK_MQ_F_NO_SCHED_BY_DEFAULT; |
|
lo->tag_set.driver_data = lo; |
|
|
|
err = blk_mq_alloc_tag_set(&lo->tag_set); |
|
if (err) |
|
goto out_free_idr; |
|
|
|
disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, lo); |
|
if (IS_ERR(disk)) { |
|
err = PTR_ERR(disk); |
|
goto out_cleanup_tags; |
|
} |
|
lo->lo_queue = lo->lo_disk->queue; |
|
|
|
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); |
|
|
|
/* |
|
* 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; |
|
atomic_set(&lo->lo_refcnt, 0); |
|
mutex_init(&lo->lo_mutex); |
|
lo->lo_number = i; |
|
spin_lock_init(&lo->lo_lock); |
|
spin_lock_init(&lo->lo_work_lock); |
|
disk->major = LOOP_MAJOR; |
|
disk->first_minor = i << part_shift; |
|
disk->minors = 1 << part_shift; |
|
disk->fops = &lo_fops; |
|
disk->private_data = lo; |
|
disk->queue = lo->lo_queue; |
|
disk->events = DISK_EVENT_MEDIA_CHANGE; |
|
disk->event_flags = DISK_EVENT_FLAG_UEVENT; |
|
sprintf(disk->disk_name, "loop%d", i); |
|
/* Make this loop device reachable from pathname. */ |
|
err = add_disk(disk); |
|
if (err) |
|
goto out_cleanup_disk; |
|
|
|
/* Show this loop device. */ |
|
mutex_lock(&loop_ctl_mutex); |
|
lo->idr_visible = true; |
|
mutex_unlock(&loop_ctl_mutex); |
|
|
|
return i; |
|
|
|
out_cleanup_disk: |
|
blk_cleanup_disk(disk); |
|
out_cleanup_tags: |
|
blk_mq_free_tag_set(&lo->tag_set); |
|
out_free_idr: |
|
mutex_lock(&loop_ctl_mutex); |
|
idr_remove(&loop_index_idr, i); |
|
mutex_unlock(&loop_ctl_mutex); |
|
out_free_dev: |
|
kfree(lo); |
|
out: |
|
return err; |
|
} |
|
|
|
static void loop_remove(struct loop_device *lo) |
|
{ |
|
/* Make this loop device unreachable from pathname. */ |
|
del_gendisk(lo->lo_disk); |
|
blk_cleanup_disk(lo->lo_disk); |
|
blk_mq_free_tag_set(&lo->tag_set); |
|
mutex_lock(&loop_ctl_mutex); |
|
idr_remove(&loop_index_idr, lo->lo_number); |
|
mutex_unlock(&loop_ctl_mutex); |
|
/* There is no route which can find this loop device. */ |
|
mutex_destroy(&lo->lo_mutex); |
|
kfree(lo); |
|
} |
|
|
|
static void loop_probe(dev_t dev) |
|
{ |
|
int idx = MINOR(dev) >> part_shift; |
|
|
|
if (max_loop && idx >= max_loop) |
|
return; |
|
loop_add(idx); |
|
} |
|
|
|
static int loop_control_remove(int idx) |
|
{ |
|
struct loop_device *lo; |
|
int ret; |
|
|
|
if (idx < 0) { |
|
pr_warn_once("deleting an unspecified loop device is not supported.\n"); |
|
return -EINVAL; |
|
} |
|
|
|
/* Hide this loop device for serialization. */ |
|
ret = mutex_lock_killable(&loop_ctl_mutex); |
|
if (ret) |
|
return ret; |
|
lo = idr_find(&loop_index_idr, idx); |
|
if (!lo || !lo->idr_visible) |
|
ret = -ENODEV; |
|
else |
|
lo->idr_visible = false; |
|
mutex_unlock(&loop_ctl_mutex); |
|
if (ret) |
|
return ret; |
|
|
|
/* Check whether this loop device can be removed. */ |
|
ret = mutex_lock_killable(&lo->lo_mutex); |
|
if (ret) |
|
goto mark_visible; |
|
if (lo->lo_state != Lo_unbound || |
|
atomic_read(&lo->lo_refcnt) > 0) { |
|
mutex_unlock(&lo->lo_mutex); |
|
ret = -EBUSY; |
|
goto mark_visible; |
|
} |
|
/* Mark this loop device no longer open()-able. */ |
|
lo->lo_state = Lo_deleting; |
|
mutex_unlock(&lo->lo_mutex); |
|
|
|
loop_remove(lo); |
|
return 0; |
|
|
|
mark_visible: |
|
/* Show this loop device again. */ |
|
mutex_lock(&loop_ctl_mutex); |
|
lo->idr_visible = true; |
|
mutex_unlock(&loop_ctl_mutex); |
|
return ret; |
|
} |
|
|
|
static int loop_control_get_free(int idx) |
|
{ |
|
struct loop_device *lo; |
|
int id, ret; |
|
|
|
ret = mutex_lock_killable(&loop_ctl_mutex); |
|
if (ret) |
|
return ret; |
|
idr_for_each_entry(&loop_index_idr, lo, id) { |
|
/* Hitting a race results in creating a new loop device which is harmless. */ |
|
if (lo->idr_visible && data_race(lo->lo_state) == Lo_unbound) |
|
goto found; |
|
} |
|
mutex_unlock(&loop_ctl_mutex); |
|
return loop_add(-1); |
|
found: |
|
mutex_unlock(&loop_ctl_mutex); |
|
return id; |
|
} |
|
|
|
static long loop_control_ioctl(struct file *file, unsigned int cmd, |
|
unsigned long parm) |
|
{ |
|
switch (cmd) { |
|
case LOOP_CTL_ADD: |
|
return loop_add(parm); |
|
case LOOP_CTL_REMOVE: |
|
return loop_control_remove(parm); |
|
case LOOP_CTL_GET_FREE: |
|
return loop_control_get_free(parm); |
|
default: |
|
return -ENOSYS; |
|
} |
|
} |
|
|
|
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; |
|
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; |
|
else |
|
nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT; |
|
|
|
err = misc_register(&loop_misc); |
|
if (err < 0) |
|
goto err_out; |
|
|
|
|
|
if (__register_blkdev(LOOP_MAJOR, "loop", loop_probe)) { |
|
err = -EIO; |
|
goto misc_out; |
|
} |
|
|
|
/* pre-create number of devices given by config or max_loop */ |
|
for (i = 0; i < nr; i++) |
|
loop_add(i); |
|
|
|
printk(KERN_INFO "loop: module loaded\n"); |
|
return 0; |
|
|
|
misc_out: |
|
misc_deregister(&loop_misc); |
|
err_out: |
|
return err; |
|
} |
|
|
|
static void __exit loop_exit(void) |
|
{ |
|
struct loop_device *lo; |
|
int id; |
|
|
|
unregister_blkdev(LOOP_MAJOR, "loop"); |
|
misc_deregister(&loop_misc); |
|
|
|
/* |
|
* There is no need to use loop_ctl_mutex here, for nobody else can |
|
* access loop_index_idr when this module is unloading (unless forced |
|
* module unloading is requested). If this is not a clean unloading, |
|
* we have no means to avoid kernel crash. |
|
*/ |
|
idr_for_each_entry(&loop_index_idr, lo, id) |
|
loop_remove(lo); |
|
|
|
idr_destroy(&loop_index_idr); |
|
} |
|
|
|
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
|
|
|