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1821 lines
37 KiB
1821 lines
37 KiB
/*
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* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
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* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include "dm.h"
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#include "dm-uevent.h"
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/moduleparam.h>
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#include <linux/blkpg.h>
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#include <linux/bio.h>
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#include <linux/buffer_head.h>
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#include <linux/mempool.h>
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#include <linux/slab.h>
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#include <linux/idr.h>
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#include <linux/hdreg.h>
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#include <linux/blktrace_api.h>
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#include <trace/events/block.h>
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#define DM_MSG_PREFIX "core"
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static const char *_name = DM_NAME;
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static unsigned int major = 0;
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static unsigned int _major = 0;
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static DEFINE_SPINLOCK(_minor_lock);
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/*
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* For bio-based dm.
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* One of these is allocated per bio.
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*/
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struct dm_io {
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struct mapped_device *md;
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int error;
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atomic_t io_count;
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struct bio *bio;
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unsigned long start_time;
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};
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/*
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* For bio-based dm.
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* One of these is allocated per target within a bio. Hopefully
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* this will be simplified out one day.
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*/
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struct dm_target_io {
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struct dm_io *io;
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struct dm_target *ti;
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union map_info info;
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};
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/*
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* For request-based dm.
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* One of these is allocated per request.
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*/
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struct dm_rq_target_io {
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struct mapped_device *md;
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struct dm_target *ti;
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struct request *orig, clone;
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int error;
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union map_info info;
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};
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/*
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* For request-based dm.
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* One of these is allocated per bio.
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*/
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struct dm_rq_clone_bio_info {
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struct bio *orig;
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struct request *rq;
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};
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union map_info *dm_get_mapinfo(struct bio *bio)
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{
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if (bio && bio->bi_private)
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return &((struct dm_target_io *)bio->bi_private)->info;
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return NULL;
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}
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#define MINOR_ALLOCED ((void *)-1)
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/*
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* Bits for the md->flags field.
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*/
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#define DMF_BLOCK_IO_FOR_SUSPEND 0
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#define DMF_SUSPENDED 1
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#define DMF_FROZEN 2
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#define DMF_FREEING 3
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#define DMF_DELETING 4
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#define DMF_NOFLUSH_SUSPENDING 5
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#define DMF_QUEUE_IO_TO_THREAD 6
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/*
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* Work processed by per-device workqueue.
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*/
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struct mapped_device {
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struct rw_semaphore io_lock;
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struct mutex suspend_lock;
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rwlock_t map_lock;
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atomic_t holders;
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atomic_t open_count;
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unsigned long flags;
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struct request_queue *queue;
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struct gendisk *disk;
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char name[16];
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void *interface_ptr;
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/*
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* A list of ios that arrived while we were suspended.
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*/
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atomic_t pending;
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wait_queue_head_t wait;
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struct work_struct work;
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struct bio_list deferred;
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spinlock_t deferred_lock;
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/*
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* An error from the barrier request currently being processed.
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*/
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int barrier_error;
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/*
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* Processing queue (flush/barriers)
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*/
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struct workqueue_struct *wq;
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/*
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* The current mapping.
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*/
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struct dm_table *map;
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/*
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* io objects are allocated from here.
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*/
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mempool_t *io_pool;
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mempool_t *tio_pool;
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struct bio_set *bs;
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/*
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* Event handling.
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*/
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atomic_t event_nr;
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wait_queue_head_t eventq;
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atomic_t uevent_seq;
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struct list_head uevent_list;
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spinlock_t uevent_lock; /* Protect access to uevent_list */
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/*
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* freeze/thaw support require holding onto a super block
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*/
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struct super_block *frozen_sb;
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struct block_device *suspended_bdev;
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/* forced geometry settings */
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struct hd_geometry geometry;
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/* sysfs handle */
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struct kobject kobj;
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};
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#define MIN_IOS 256
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static struct kmem_cache *_io_cache;
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static struct kmem_cache *_tio_cache;
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static struct kmem_cache *_rq_tio_cache;
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static struct kmem_cache *_rq_bio_info_cache;
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static int __init local_init(void)
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{
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int r = -ENOMEM;
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/* allocate a slab for the dm_ios */
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_io_cache = KMEM_CACHE(dm_io, 0);
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if (!_io_cache)
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return r;
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/* allocate a slab for the target ios */
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_tio_cache = KMEM_CACHE(dm_target_io, 0);
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if (!_tio_cache)
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goto out_free_io_cache;
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_rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
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if (!_rq_tio_cache)
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goto out_free_tio_cache;
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_rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
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if (!_rq_bio_info_cache)
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goto out_free_rq_tio_cache;
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r = dm_uevent_init();
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if (r)
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goto out_free_rq_bio_info_cache;
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_major = major;
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r = register_blkdev(_major, _name);
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if (r < 0)
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goto out_uevent_exit;
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if (!_major)
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_major = r;
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return 0;
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out_uevent_exit:
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dm_uevent_exit();
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out_free_rq_bio_info_cache:
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kmem_cache_destroy(_rq_bio_info_cache);
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out_free_rq_tio_cache:
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kmem_cache_destroy(_rq_tio_cache);
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out_free_tio_cache:
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kmem_cache_destroy(_tio_cache);
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out_free_io_cache:
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kmem_cache_destroy(_io_cache);
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return r;
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}
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static void local_exit(void)
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{
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kmem_cache_destroy(_rq_bio_info_cache);
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kmem_cache_destroy(_rq_tio_cache);
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kmem_cache_destroy(_tio_cache);
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kmem_cache_destroy(_io_cache);
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unregister_blkdev(_major, _name);
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dm_uevent_exit();
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_major = 0;
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DMINFO("cleaned up");
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}
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static int (*_inits[])(void) __initdata = {
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local_init,
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dm_target_init,
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dm_linear_init,
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dm_stripe_init,
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dm_kcopyd_init,
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dm_interface_init,
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};
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static void (*_exits[])(void) = {
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local_exit,
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dm_target_exit,
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dm_linear_exit,
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dm_stripe_exit,
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dm_kcopyd_exit,
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dm_interface_exit,
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};
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static int __init dm_init(void)
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{
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const int count = ARRAY_SIZE(_inits);
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int r, i;
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for (i = 0; i < count; i++) {
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r = _inits[i]();
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if (r)
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goto bad;
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}
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return 0;
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bad:
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while (i--)
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_exits[i]();
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return r;
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}
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static void __exit dm_exit(void)
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{
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int i = ARRAY_SIZE(_exits);
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while (i--)
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_exits[i]();
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}
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/*
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* Block device functions
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*/
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static int dm_blk_open(struct block_device *bdev, fmode_t mode)
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{
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struct mapped_device *md;
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spin_lock(&_minor_lock);
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md = bdev->bd_disk->private_data;
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if (!md)
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goto out;
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if (test_bit(DMF_FREEING, &md->flags) ||
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test_bit(DMF_DELETING, &md->flags)) {
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md = NULL;
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goto out;
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}
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dm_get(md);
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atomic_inc(&md->open_count);
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out:
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spin_unlock(&_minor_lock);
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return md ? 0 : -ENXIO;
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}
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static int dm_blk_close(struct gendisk *disk, fmode_t mode)
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{
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struct mapped_device *md = disk->private_data;
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atomic_dec(&md->open_count);
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dm_put(md);
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return 0;
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}
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int dm_open_count(struct mapped_device *md)
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{
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return atomic_read(&md->open_count);
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}
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/*
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* Guarantees nothing is using the device before it's deleted.
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*/
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int dm_lock_for_deletion(struct mapped_device *md)
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{
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int r = 0;
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spin_lock(&_minor_lock);
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if (dm_open_count(md))
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r = -EBUSY;
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else
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set_bit(DMF_DELETING, &md->flags);
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spin_unlock(&_minor_lock);
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return r;
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}
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static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
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{
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struct mapped_device *md = bdev->bd_disk->private_data;
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return dm_get_geometry(md, geo);
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}
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static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
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unsigned int cmd, unsigned long arg)
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{
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struct mapped_device *md = bdev->bd_disk->private_data;
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struct dm_table *map = dm_get_table(md);
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struct dm_target *tgt;
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int r = -ENOTTY;
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if (!map || !dm_table_get_size(map))
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goto out;
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/* We only support devices that have a single target */
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if (dm_table_get_num_targets(map) != 1)
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goto out;
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tgt = dm_table_get_target(map, 0);
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if (dm_suspended(md)) {
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r = -EAGAIN;
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goto out;
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}
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if (tgt->type->ioctl)
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r = tgt->type->ioctl(tgt, cmd, arg);
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out:
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dm_table_put(map);
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return r;
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}
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static struct dm_io *alloc_io(struct mapped_device *md)
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{
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return mempool_alloc(md->io_pool, GFP_NOIO);
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}
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static void free_io(struct mapped_device *md, struct dm_io *io)
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{
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mempool_free(io, md->io_pool);
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}
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static struct dm_target_io *alloc_tio(struct mapped_device *md)
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{
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return mempool_alloc(md->tio_pool, GFP_NOIO);
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}
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static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
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{
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mempool_free(tio, md->tio_pool);
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}
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static void start_io_acct(struct dm_io *io)
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{
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struct mapped_device *md = io->md;
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int cpu;
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io->start_time = jiffies;
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cpu = part_stat_lock();
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part_round_stats(cpu, &dm_disk(md)->part0);
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part_stat_unlock();
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dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
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}
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static void end_io_acct(struct dm_io *io)
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{
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struct mapped_device *md = io->md;
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struct bio *bio = io->bio;
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unsigned long duration = jiffies - io->start_time;
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int pending, cpu;
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int rw = bio_data_dir(bio);
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cpu = part_stat_lock();
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part_round_stats(cpu, &dm_disk(md)->part0);
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part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
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part_stat_unlock();
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/*
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* After this is decremented the bio must not be touched if it is
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* a barrier.
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*/
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dm_disk(md)->part0.in_flight = pending =
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atomic_dec_return(&md->pending);
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/* nudge anyone waiting on suspend queue */
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if (!pending)
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wake_up(&md->wait);
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}
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|
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/*
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* Add the bio to the list of deferred io.
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*/
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static void queue_io(struct mapped_device *md, struct bio *bio)
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{
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down_write(&md->io_lock);
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spin_lock_irq(&md->deferred_lock);
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bio_list_add(&md->deferred, bio);
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spin_unlock_irq(&md->deferred_lock);
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if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))
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queue_work(md->wq, &md->work);
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up_write(&md->io_lock);
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}
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|
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/*
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* Everyone (including functions in this file), should use this
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* function to access the md->map field, and make sure they call
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* dm_table_put() when finished.
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*/
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struct dm_table *dm_get_table(struct mapped_device *md)
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{
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struct dm_table *t;
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read_lock(&md->map_lock);
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t = md->map;
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if (t)
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dm_table_get(t);
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read_unlock(&md->map_lock);
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return t;
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}
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|
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/*
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* Get the geometry associated with a dm device
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*/
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int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
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{
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*geo = md->geometry;
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|
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return 0;
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}
|
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|
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/*
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* Set the geometry of a device.
|
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*/
|
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int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
|
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{
|
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sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
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|
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if (geo->start > sz) {
|
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DMWARN("Start sector is beyond the geometry limits.");
|
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return -EINVAL;
|
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}
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|
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md->geometry = *geo;
|
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|
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return 0;
|
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}
|
|
|
|
/*-----------------------------------------------------------------
|
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* CRUD START:
|
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* A more elegant soln is in the works that uses the queue
|
|
* merge fn, unfortunately there are a couple of changes to
|
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* the block layer that I want to make for this. So in the
|
|
* interests of getting something for people to use I give
|
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* you this clearly demarcated crap.
|
|
*---------------------------------------------------------------*/
|
|
|
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static int __noflush_suspending(struct mapped_device *md)
|
|
{
|
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return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
|
|
}
|
|
|
|
/*
|
|
* Decrements the number of outstanding ios that a bio has been
|
|
* cloned into, completing the original io if necc.
|
|
*/
|
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static void dec_pending(struct dm_io *io, int error)
|
|
{
|
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unsigned long flags;
|
|
int io_error;
|
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struct bio *bio;
|
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struct mapped_device *md = io->md;
|
|
|
|
/* Push-back supersedes any I/O errors */
|
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if (error && !(io->error > 0 && __noflush_suspending(md)))
|
|
io->error = error;
|
|
|
|
if (atomic_dec_and_test(&io->io_count)) {
|
|
if (io->error == DM_ENDIO_REQUEUE) {
|
|
/*
|
|
* Target requested pushing back the I/O.
|
|
*/
|
|
spin_lock_irqsave(&md->deferred_lock, flags);
|
|
if (__noflush_suspending(md))
|
|
bio_list_add_head(&md->deferred, io->bio);
|
|
else
|
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/* noflush suspend was interrupted. */
|
|
io->error = -EIO;
|
|
spin_unlock_irqrestore(&md->deferred_lock, flags);
|
|
}
|
|
|
|
io_error = io->error;
|
|
bio = io->bio;
|
|
|
|
if (bio_barrier(bio)) {
|
|
/*
|
|
* There can be just one barrier request so we use
|
|
* a per-device variable for error reporting.
|
|
* Note that you can't touch the bio after end_io_acct
|
|
*/
|
|
md->barrier_error = io_error;
|
|
end_io_acct(io);
|
|
} else {
|
|
end_io_acct(io);
|
|
|
|
if (io_error != DM_ENDIO_REQUEUE) {
|
|
trace_block_bio_complete(md->queue, bio);
|
|
|
|
bio_endio(bio, io_error);
|
|
}
|
|
}
|
|
|
|
free_io(md, io);
|
|
}
|
|
}
|
|
|
|
static void clone_endio(struct bio *bio, int error)
|
|
{
|
|
int r = 0;
|
|
struct dm_target_io *tio = bio->bi_private;
|
|
struct dm_io *io = tio->io;
|
|
struct mapped_device *md = tio->io->md;
|
|
dm_endio_fn endio = tio->ti->type->end_io;
|
|
|
|
if (!bio_flagged(bio, BIO_UPTODATE) && !error)
|
|
error = -EIO;
|
|
|
|
if (endio) {
|
|
r = endio(tio->ti, bio, error, &tio->info);
|
|
if (r < 0 || r == DM_ENDIO_REQUEUE)
|
|
/*
|
|
* error and requeue request are handled
|
|
* in dec_pending().
|
|
*/
|
|
error = r;
|
|
else if (r == DM_ENDIO_INCOMPLETE)
|
|
/* The target will handle the io */
|
|
return;
|
|
else if (r) {
|
|
DMWARN("unimplemented target endio return value: %d", r);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Store md for cleanup instead of tio which is about to get freed.
|
|
*/
|
|
bio->bi_private = md->bs;
|
|
|
|
free_tio(md, tio);
|
|
bio_put(bio);
|
|
dec_pending(io, error);
|
|
}
|
|
|
|
static sector_t max_io_len(struct mapped_device *md,
|
|
sector_t sector, struct dm_target *ti)
|
|
{
|
|
sector_t offset = sector - ti->begin;
|
|
sector_t len = ti->len - offset;
|
|
|
|
/*
|
|
* Does the target need to split even further ?
|
|
*/
|
|
if (ti->split_io) {
|
|
sector_t boundary;
|
|
boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
|
|
- offset;
|
|
if (len > boundary)
|
|
len = boundary;
|
|
}
|
|
|
|
return len;
|
|
}
|
|
|
|
static void __map_bio(struct dm_target *ti, struct bio *clone,
|
|
struct dm_target_io *tio)
|
|
{
|
|
int r;
|
|
sector_t sector;
|
|
struct mapped_device *md;
|
|
|
|
/*
|
|
* Sanity checks.
|
|
*/
|
|
BUG_ON(!clone->bi_size);
|
|
|
|
clone->bi_end_io = clone_endio;
|
|
clone->bi_private = tio;
|
|
|
|
/*
|
|
* Map the clone. If r == 0 we don't need to do
|
|
* anything, the target has assumed ownership of
|
|
* this io.
|
|
*/
|
|
atomic_inc(&tio->io->io_count);
|
|
sector = clone->bi_sector;
|
|
r = ti->type->map(ti, clone, &tio->info);
|
|
if (r == DM_MAPIO_REMAPPED) {
|
|
/* the bio has been remapped so dispatch it */
|
|
|
|
trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
|
|
tio->io->bio->bi_bdev->bd_dev, sector);
|
|
|
|
generic_make_request(clone);
|
|
} else if (r < 0 || r == DM_MAPIO_REQUEUE) {
|
|
/* error the io and bail out, or requeue it if needed */
|
|
md = tio->io->md;
|
|
dec_pending(tio->io, r);
|
|
/*
|
|
* Store bio_set for cleanup.
|
|
*/
|
|
clone->bi_private = md->bs;
|
|
bio_put(clone);
|
|
free_tio(md, tio);
|
|
} else if (r) {
|
|
DMWARN("unimplemented target map return value: %d", r);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
struct clone_info {
|
|
struct mapped_device *md;
|
|
struct dm_table *map;
|
|
struct bio *bio;
|
|
struct dm_io *io;
|
|
sector_t sector;
|
|
sector_t sector_count;
|
|
unsigned short idx;
|
|
};
|
|
|
|
static void dm_bio_destructor(struct bio *bio)
|
|
{
|
|
struct bio_set *bs = bio->bi_private;
|
|
|
|
bio_free(bio, bs);
|
|
}
|
|
|
|
/*
|
|
* Creates a little bio that is just does part of a bvec.
|
|
*/
|
|
static struct bio *split_bvec(struct bio *bio, sector_t sector,
|
|
unsigned short idx, unsigned int offset,
|
|
unsigned int len, struct bio_set *bs)
|
|
{
|
|
struct bio *clone;
|
|
struct bio_vec *bv = bio->bi_io_vec + idx;
|
|
|
|
clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
|
|
clone->bi_destructor = dm_bio_destructor;
|
|
*clone->bi_io_vec = *bv;
|
|
|
|
clone->bi_sector = sector;
|
|
clone->bi_bdev = bio->bi_bdev;
|
|
clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER);
|
|
clone->bi_vcnt = 1;
|
|
clone->bi_size = to_bytes(len);
|
|
clone->bi_io_vec->bv_offset = offset;
|
|
clone->bi_io_vec->bv_len = clone->bi_size;
|
|
clone->bi_flags |= 1 << BIO_CLONED;
|
|
|
|
if (bio_integrity(bio)) {
|
|
bio_integrity_clone(clone, bio, GFP_NOIO);
|
|
bio_integrity_trim(clone,
|
|
bio_sector_offset(bio, idx, offset), len);
|
|
}
|
|
|
|
return clone;
|
|
}
|
|
|
|
/*
|
|
* Creates a bio that consists of range of complete bvecs.
|
|
*/
|
|
static struct bio *clone_bio(struct bio *bio, sector_t sector,
|
|
unsigned short idx, unsigned short bv_count,
|
|
unsigned int len, struct bio_set *bs)
|
|
{
|
|
struct bio *clone;
|
|
|
|
clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
|
|
__bio_clone(clone, bio);
|
|
clone->bi_rw &= ~(1 << BIO_RW_BARRIER);
|
|
clone->bi_destructor = dm_bio_destructor;
|
|
clone->bi_sector = sector;
|
|
clone->bi_idx = idx;
|
|
clone->bi_vcnt = idx + bv_count;
|
|
clone->bi_size = to_bytes(len);
|
|
clone->bi_flags &= ~(1 << BIO_SEG_VALID);
|
|
|
|
if (bio_integrity(bio)) {
|
|
bio_integrity_clone(clone, bio, GFP_NOIO);
|
|
|
|
if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
|
|
bio_integrity_trim(clone,
|
|
bio_sector_offset(bio, idx, 0), len);
|
|
}
|
|
|
|
return clone;
|
|
}
|
|
|
|
static int __clone_and_map(struct clone_info *ci)
|
|
{
|
|
struct bio *clone, *bio = ci->bio;
|
|
struct dm_target *ti;
|
|
sector_t len = 0, max;
|
|
struct dm_target_io *tio;
|
|
|
|
ti = dm_table_find_target(ci->map, ci->sector);
|
|
if (!dm_target_is_valid(ti))
|
|
return -EIO;
|
|
|
|
max = max_io_len(ci->md, ci->sector, ti);
|
|
|
|
/*
|
|
* Allocate a target io object.
|
|
*/
|
|
tio = alloc_tio(ci->md);
|
|
tio->io = ci->io;
|
|
tio->ti = ti;
|
|
memset(&tio->info, 0, sizeof(tio->info));
|
|
|
|
if (ci->sector_count <= max) {
|
|
/*
|
|
* Optimise for the simple case where we can do all of
|
|
* the remaining io with a single clone.
|
|
*/
|
|
clone = clone_bio(bio, ci->sector, ci->idx,
|
|
bio->bi_vcnt - ci->idx, ci->sector_count,
|
|
ci->md->bs);
|
|
__map_bio(ti, clone, tio);
|
|
ci->sector_count = 0;
|
|
|
|
} else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
|
|
/*
|
|
* There are some bvecs that don't span targets.
|
|
* Do as many of these as possible.
|
|
*/
|
|
int i;
|
|
sector_t remaining = max;
|
|
sector_t bv_len;
|
|
|
|
for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
|
|
bv_len = to_sector(bio->bi_io_vec[i].bv_len);
|
|
|
|
if (bv_len > remaining)
|
|
break;
|
|
|
|
remaining -= bv_len;
|
|
len += bv_len;
|
|
}
|
|
|
|
clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
|
|
ci->md->bs);
|
|
__map_bio(ti, clone, tio);
|
|
|
|
ci->sector += len;
|
|
ci->sector_count -= len;
|
|
ci->idx = i;
|
|
|
|
} else {
|
|
/*
|
|
* Handle a bvec that must be split between two or more targets.
|
|
*/
|
|
struct bio_vec *bv = bio->bi_io_vec + ci->idx;
|
|
sector_t remaining = to_sector(bv->bv_len);
|
|
unsigned int offset = 0;
|
|
|
|
do {
|
|
if (offset) {
|
|
ti = dm_table_find_target(ci->map, ci->sector);
|
|
if (!dm_target_is_valid(ti))
|
|
return -EIO;
|
|
|
|
max = max_io_len(ci->md, ci->sector, ti);
|
|
|
|
tio = alloc_tio(ci->md);
|
|
tio->io = ci->io;
|
|
tio->ti = ti;
|
|
memset(&tio->info, 0, sizeof(tio->info));
|
|
}
|
|
|
|
len = min(remaining, max);
|
|
|
|
clone = split_bvec(bio, ci->sector, ci->idx,
|
|
bv->bv_offset + offset, len,
|
|
ci->md->bs);
|
|
|
|
__map_bio(ti, clone, tio);
|
|
|
|
ci->sector += len;
|
|
ci->sector_count -= len;
|
|
offset += to_bytes(len);
|
|
} while (remaining -= len);
|
|
|
|
ci->idx++;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Split the bio into several clones and submit it to targets.
|
|
*/
|
|
static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
|
|
{
|
|
struct clone_info ci;
|
|
int error = 0;
|
|
|
|
ci.map = dm_get_table(md);
|
|
if (unlikely(!ci.map)) {
|
|
if (!bio_barrier(bio))
|
|
bio_io_error(bio);
|
|
else
|
|
md->barrier_error = -EIO;
|
|
return;
|
|
}
|
|
|
|
ci.md = md;
|
|
ci.bio = bio;
|
|
ci.io = alloc_io(md);
|
|
ci.io->error = 0;
|
|
atomic_set(&ci.io->io_count, 1);
|
|
ci.io->bio = bio;
|
|
ci.io->md = md;
|
|
ci.sector = bio->bi_sector;
|
|
ci.sector_count = bio_sectors(bio);
|
|
ci.idx = bio->bi_idx;
|
|
|
|
start_io_acct(ci.io);
|
|
while (ci.sector_count && !error)
|
|
error = __clone_and_map(&ci);
|
|
|
|
/* drop the extra reference count */
|
|
dec_pending(ci.io, error);
|
|
dm_table_put(ci.map);
|
|
}
|
|
/*-----------------------------------------------------------------
|
|
* CRUD END
|
|
*---------------------------------------------------------------*/
|
|
|
|
static int dm_merge_bvec(struct request_queue *q,
|
|
struct bvec_merge_data *bvm,
|
|
struct bio_vec *biovec)
|
|
{
|
|
struct mapped_device *md = q->queuedata;
|
|
struct dm_table *map = dm_get_table(md);
|
|
struct dm_target *ti;
|
|
sector_t max_sectors;
|
|
int max_size = 0;
|
|
|
|
if (unlikely(!map))
|
|
goto out;
|
|
|
|
ti = dm_table_find_target(map, bvm->bi_sector);
|
|
if (!dm_target_is_valid(ti))
|
|
goto out_table;
|
|
|
|
/*
|
|
* Find maximum amount of I/O that won't need splitting
|
|
*/
|
|
max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
|
|
(sector_t) BIO_MAX_SECTORS);
|
|
max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
|
|
if (max_size < 0)
|
|
max_size = 0;
|
|
|
|
/*
|
|
* merge_bvec_fn() returns number of bytes
|
|
* it can accept at this offset
|
|
* max is precomputed maximal io size
|
|
*/
|
|
if (max_size && ti->type->merge)
|
|
max_size = ti->type->merge(ti, bvm, biovec, max_size);
|
|
|
|
out_table:
|
|
dm_table_put(map);
|
|
|
|
out:
|
|
/*
|
|
* Always allow an entire first page
|
|
*/
|
|
if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
|
|
max_size = biovec->bv_len;
|
|
|
|
return max_size;
|
|
}
|
|
|
|
/*
|
|
* The request function that just remaps the bio built up by
|
|
* dm_merge_bvec.
|
|
*/
|
|
static int dm_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
int rw = bio_data_dir(bio);
|
|
struct mapped_device *md = q->queuedata;
|
|
int cpu;
|
|
|
|
down_read(&md->io_lock);
|
|
|
|
cpu = part_stat_lock();
|
|
part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
|
|
part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
|
|
part_stat_unlock();
|
|
|
|
/*
|
|
* If we're suspended or the thread is processing barriers
|
|
* we have to queue this io for later.
|
|
*/
|
|
if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) ||
|
|
unlikely(bio_barrier(bio))) {
|
|
up_read(&md->io_lock);
|
|
|
|
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&
|
|
bio_rw(bio) == READA) {
|
|
bio_io_error(bio);
|
|
return 0;
|
|
}
|
|
|
|
queue_io(md, bio);
|
|
|
|
return 0;
|
|
}
|
|
|
|
__split_and_process_bio(md, bio);
|
|
up_read(&md->io_lock);
|
|
return 0;
|
|
}
|
|
|
|
static void dm_unplug_all(struct request_queue *q)
|
|
{
|
|
struct mapped_device *md = q->queuedata;
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
if (map) {
|
|
dm_table_unplug_all(map);
|
|
dm_table_put(map);
|
|
}
|
|
}
|
|
|
|
static int dm_any_congested(void *congested_data, int bdi_bits)
|
|
{
|
|
int r = bdi_bits;
|
|
struct mapped_device *md = congested_data;
|
|
struct dm_table *map;
|
|
|
|
if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
|
|
map = dm_get_table(md);
|
|
if (map) {
|
|
r = dm_table_any_congested(map, bdi_bits);
|
|
dm_table_put(map);
|
|
}
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* An IDR is used to keep track of allocated minor numbers.
|
|
*---------------------------------------------------------------*/
|
|
static DEFINE_IDR(_minor_idr);
|
|
|
|
static void free_minor(int minor)
|
|
{
|
|
spin_lock(&_minor_lock);
|
|
idr_remove(&_minor_idr, minor);
|
|
spin_unlock(&_minor_lock);
|
|
}
|
|
|
|
/*
|
|
* See if the device with a specific minor # is free.
|
|
*/
|
|
static int specific_minor(int minor)
|
|
{
|
|
int r, m;
|
|
|
|
if (minor >= (1 << MINORBITS))
|
|
return -EINVAL;
|
|
|
|
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
|
|
if (!r)
|
|
return -ENOMEM;
|
|
|
|
spin_lock(&_minor_lock);
|
|
|
|
if (idr_find(&_minor_idr, minor)) {
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
|
|
if (r)
|
|
goto out;
|
|
|
|
if (m != minor) {
|
|
idr_remove(&_minor_idr, m);
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
spin_unlock(&_minor_lock);
|
|
return r;
|
|
}
|
|
|
|
static int next_free_minor(int *minor)
|
|
{
|
|
int r, m;
|
|
|
|
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
|
|
if (!r)
|
|
return -ENOMEM;
|
|
|
|
spin_lock(&_minor_lock);
|
|
|
|
r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
|
|
if (r)
|
|
goto out;
|
|
|
|
if (m >= (1 << MINORBITS)) {
|
|
idr_remove(&_minor_idr, m);
|
|
r = -ENOSPC;
|
|
goto out;
|
|
}
|
|
|
|
*minor = m;
|
|
|
|
out:
|
|
spin_unlock(&_minor_lock);
|
|
return r;
|
|
}
|
|
|
|
static struct block_device_operations dm_blk_dops;
|
|
|
|
static void dm_wq_work(struct work_struct *work);
|
|
|
|
/*
|
|
* Allocate and initialise a blank device with a given minor.
|
|
*/
|
|
static struct mapped_device *alloc_dev(int minor)
|
|
{
|
|
int r;
|
|
struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
|
|
void *old_md;
|
|
|
|
if (!md) {
|
|
DMWARN("unable to allocate device, out of memory.");
|
|
return NULL;
|
|
}
|
|
|
|
if (!try_module_get(THIS_MODULE))
|
|
goto bad_module_get;
|
|
|
|
/* get a minor number for the dev */
|
|
if (minor == DM_ANY_MINOR)
|
|
r = next_free_minor(&minor);
|
|
else
|
|
r = specific_minor(minor);
|
|
if (r < 0)
|
|
goto bad_minor;
|
|
|
|
init_rwsem(&md->io_lock);
|
|
mutex_init(&md->suspend_lock);
|
|
spin_lock_init(&md->deferred_lock);
|
|
rwlock_init(&md->map_lock);
|
|
atomic_set(&md->holders, 1);
|
|
atomic_set(&md->open_count, 0);
|
|
atomic_set(&md->event_nr, 0);
|
|
atomic_set(&md->uevent_seq, 0);
|
|
INIT_LIST_HEAD(&md->uevent_list);
|
|
spin_lock_init(&md->uevent_lock);
|
|
|
|
md->queue = blk_alloc_queue(GFP_KERNEL);
|
|
if (!md->queue)
|
|
goto bad_queue;
|
|
|
|
md->queue->queuedata = md;
|
|
md->queue->backing_dev_info.congested_fn = dm_any_congested;
|
|
md->queue->backing_dev_info.congested_data = md;
|
|
blk_queue_make_request(md->queue, dm_request);
|
|
blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL);
|
|
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
|
|
md->queue->unplug_fn = dm_unplug_all;
|
|
blk_queue_merge_bvec(md->queue, dm_merge_bvec);
|
|
|
|
md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
|
|
if (!md->io_pool)
|
|
goto bad_io_pool;
|
|
|
|
md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
|
|
if (!md->tio_pool)
|
|
goto bad_tio_pool;
|
|
|
|
md->bs = bioset_create(16, 0);
|
|
if (!md->bs)
|
|
goto bad_no_bioset;
|
|
|
|
md->disk = alloc_disk(1);
|
|
if (!md->disk)
|
|
goto bad_disk;
|
|
|
|
atomic_set(&md->pending, 0);
|
|
init_waitqueue_head(&md->wait);
|
|
INIT_WORK(&md->work, dm_wq_work);
|
|
init_waitqueue_head(&md->eventq);
|
|
|
|
md->disk->major = _major;
|
|
md->disk->first_minor = minor;
|
|
md->disk->fops = &dm_blk_dops;
|
|
md->disk->queue = md->queue;
|
|
md->disk->private_data = md;
|
|
sprintf(md->disk->disk_name, "dm-%d", minor);
|
|
add_disk(md->disk);
|
|
format_dev_t(md->name, MKDEV(_major, minor));
|
|
|
|
md->wq = create_singlethread_workqueue("kdmflush");
|
|
if (!md->wq)
|
|
goto bad_thread;
|
|
|
|
/* Populate the mapping, nobody knows we exist yet */
|
|
spin_lock(&_minor_lock);
|
|
old_md = idr_replace(&_minor_idr, md, minor);
|
|
spin_unlock(&_minor_lock);
|
|
|
|
BUG_ON(old_md != MINOR_ALLOCED);
|
|
|
|
return md;
|
|
|
|
bad_thread:
|
|
put_disk(md->disk);
|
|
bad_disk:
|
|
bioset_free(md->bs);
|
|
bad_no_bioset:
|
|
mempool_destroy(md->tio_pool);
|
|
bad_tio_pool:
|
|
mempool_destroy(md->io_pool);
|
|
bad_io_pool:
|
|
blk_cleanup_queue(md->queue);
|
|
bad_queue:
|
|
free_minor(minor);
|
|
bad_minor:
|
|
module_put(THIS_MODULE);
|
|
bad_module_get:
|
|
kfree(md);
|
|
return NULL;
|
|
}
|
|
|
|
static void unlock_fs(struct mapped_device *md);
|
|
|
|
static void free_dev(struct mapped_device *md)
|
|
{
|
|
int minor = MINOR(disk_devt(md->disk));
|
|
|
|
if (md->suspended_bdev) {
|
|
unlock_fs(md);
|
|
bdput(md->suspended_bdev);
|
|
}
|
|
destroy_workqueue(md->wq);
|
|
mempool_destroy(md->tio_pool);
|
|
mempool_destroy(md->io_pool);
|
|
bioset_free(md->bs);
|
|
blk_integrity_unregister(md->disk);
|
|
del_gendisk(md->disk);
|
|
free_minor(minor);
|
|
|
|
spin_lock(&_minor_lock);
|
|
md->disk->private_data = NULL;
|
|
spin_unlock(&_minor_lock);
|
|
|
|
put_disk(md->disk);
|
|
blk_cleanup_queue(md->queue);
|
|
module_put(THIS_MODULE);
|
|
kfree(md);
|
|
}
|
|
|
|
/*
|
|
* Bind a table to the device.
|
|
*/
|
|
static void event_callback(void *context)
|
|
{
|
|
unsigned long flags;
|
|
LIST_HEAD(uevents);
|
|
struct mapped_device *md = (struct mapped_device *) context;
|
|
|
|
spin_lock_irqsave(&md->uevent_lock, flags);
|
|
list_splice_init(&md->uevent_list, &uevents);
|
|
spin_unlock_irqrestore(&md->uevent_lock, flags);
|
|
|
|
dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
|
|
|
|
atomic_inc(&md->event_nr);
|
|
wake_up(&md->eventq);
|
|
}
|
|
|
|
static void __set_size(struct mapped_device *md, sector_t size)
|
|
{
|
|
set_capacity(md->disk, size);
|
|
|
|
mutex_lock(&md->suspended_bdev->bd_inode->i_mutex);
|
|
i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
|
|
mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex);
|
|
}
|
|
|
|
static int __bind(struct mapped_device *md, struct dm_table *t)
|
|
{
|
|
struct request_queue *q = md->queue;
|
|
sector_t size;
|
|
|
|
size = dm_table_get_size(t);
|
|
|
|
/*
|
|
* Wipe any geometry if the size of the table changed.
|
|
*/
|
|
if (size != get_capacity(md->disk))
|
|
memset(&md->geometry, 0, sizeof(md->geometry));
|
|
|
|
if (md->suspended_bdev)
|
|
__set_size(md, size);
|
|
|
|
if (!size) {
|
|
dm_table_destroy(t);
|
|
return 0;
|
|
}
|
|
|
|
dm_table_event_callback(t, event_callback, md);
|
|
|
|
write_lock(&md->map_lock);
|
|
md->map = t;
|
|
dm_table_set_restrictions(t, q);
|
|
write_unlock(&md->map_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __unbind(struct mapped_device *md)
|
|
{
|
|
struct dm_table *map = md->map;
|
|
|
|
if (!map)
|
|
return;
|
|
|
|
dm_table_event_callback(map, NULL, NULL);
|
|
write_lock(&md->map_lock);
|
|
md->map = NULL;
|
|
write_unlock(&md->map_lock);
|
|
dm_table_destroy(map);
|
|
}
|
|
|
|
/*
|
|
* Constructor for a new device.
|
|
*/
|
|
int dm_create(int minor, struct mapped_device **result)
|
|
{
|
|
struct mapped_device *md;
|
|
|
|
md = alloc_dev(minor);
|
|
if (!md)
|
|
return -ENXIO;
|
|
|
|
dm_sysfs_init(md);
|
|
|
|
*result = md;
|
|
return 0;
|
|
}
|
|
|
|
static struct mapped_device *dm_find_md(dev_t dev)
|
|
{
|
|
struct mapped_device *md;
|
|
unsigned minor = MINOR(dev);
|
|
|
|
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
|
|
return NULL;
|
|
|
|
spin_lock(&_minor_lock);
|
|
|
|
md = idr_find(&_minor_idr, minor);
|
|
if (md && (md == MINOR_ALLOCED ||
|
|
(MINOR(disk_devt(dm_disk(md))) != minor) ||
|
|
test_bit(DMF_FREEING, &md->flags))) {
|
|
md = NULL;
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
spin_unlock(&_minor_lock);
|
|
|
|
return md;
|
|
}
|
|
|
|
struct mapped_device *dm_get_md(dev_t dev)
|
|
{
|
|
struct mapped_device *md = dm_find_md(dev);
|
|
|
|
if (md)
|
|
dm_get(md);
|
|
|
|
return md;
|
|
}
|
|
|
|
void *dm_get_mdptr(struct mapped_device *md)
|
|
{
|
|
return md->interface_ptr;
|
|
}
|
|
|
|
void dm_set_mdptr(struct mapped_device *md, void *ptr)
|
|
{
|
|
md->interface_ptr = ptr;
|
|
}
|
|
|
|
void dm_get(struct mapped_device *md)
|
|
{
|
|
atomic_inc(&md->holders);
|
|
}
|
|
|
|
const char *dm_device_name(struct mapped_device *md)
|
|
{
|
|
return md->name;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_device_name);
|
|
|
|
void dm_put(struct mapped_device *md)
|
|
{
|
|
struct dm_table *map;
|
|
|
|
BUG_ON(test_bit(DMF_FREEING, &md->flags));
|
|
|
|
if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
|
|
map = dm_get_table(md);
|
|
idr_replace(&_minor_idr, MINOR_ALLOCED,
|
|
MINOR(disk_devt(dm_disk(md))));
|
|
set_bit(DMF_FREEING, &md->flags);
|
|
spin_unlock(&_minor_lock);
|
|
if (!dm_suspended(md)) {
|
|
dm_table_presuspend_targets(map);
|
|
dm_table_postsuspend_targets(map);
|
|
}
|
|
dm_sysfs_exit(md);
|
|
dm_table_put(map);
|
|
__unbind(md);
|
|
free_dev(md);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_put);
|
|
|
|
static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
|
|
{
|
|
int r = 0;
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
|
|
dm_unplug_all(md->queue);
|
|
|
|
add_wait_queue(&md->wait, &wait);
|
|
|
|
while (1) {
|
|
set_current_state(interruptible);
|
|
|
|
smp_mb();
|
|
if (!atomic_read(&md->pending))
|
|
break;
|
|
|
|
if (interruptible == TASK_INTERRUPTIBLE &&
|
|
signal_pending(current)) {
|
|
r = -EINTR;
|
|
break;
|
|
}
|
|
|
|
io_schedule();
|
|
}
|
|
set_current_state(TASK_RUNNING);
|
|
|
|
remove_wait_queue(&md->wait, &wait);
|
|
|
|
return r;
|
|
}
|
|
|
|
static int dm_flush(struct mapped_device *md)
|
|
{
|
|
dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
|
|
return 0;
|
|
}
|
|
|
|
static void process_barrier(struct mapped_device *md, struct bio *bio)
|
|
{
|
|
int error = dm_flush(md);
|
|
|
|
if (unlikely(error)) {
|
|
bio_endio(bio, error);
|
|
return;
|
|
}
|
|
if (bio_empty_barrier(bio)) {
|
|
bio_endio(bio, 0);
|
|
return;
|
|
}
|
|
|
|
__split_and_process_bio(md, bio);
|
|
|
|
error = dm_flush(md);
|
|
|
|
if (!error && md->barrier_error)
|
|
error = md->barrier_error;
|
|
|
|
if (md->barrier_error != DM_ENDIO_REQUEUE)
|
|
bio_endio(bio, error);
|
|
}
|
|
|
|
/*
|
|
* Process the deferred bios
|
|
*/
|
|
static void dm_wq_work(struct work_struct *work)
|
|
{
|
|
struct mapped_device *md = container_of(work, struct mapped_device,
|
|
work);
|
|
struct bio *c;
|
|
|
|
down_write(&md->io_lock);
|
|
|
|
while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
|
|
spin_lock_irq(&md->deferred_lock);
|
|
c = bio_list_pop(&md->deferred);
|
|
spin_unlock_irq(&md->deferred_lock);
|
|
|
|
if (!c) {
|
|
clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
|
|
break;
|
|
}
|
|
|
|
up_write(&md->io_lock);
|
|
|
|
if (bio_barrier(c))
|
|
process_barrier(md, c);
|
|
else
|
|
__split_and_process_bio(md, c);
|
|
|
|
down_write(&md->io_lock);
|
|
}
|
|
|
|
up_write(&md->io_lock);
|
|
}
|
|
|
|
static void dm_queue_flush(struct mapped_device *md)
|
|
{
|
|
clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
|
|
smp_mb__after_clear_bit();
|
|
queue_work(md->wq, &md->work);
|
|
}
|
|
|
|
/*
|
|
* Swap in a new table (destroying old one).
|
|
*/
|
|
int dm_swap_table(struct mapped_device *md, struct dm_table *table)
|
|
{
|
|
int r = -EINVAL;
|
|
|
|
mutex_lock(&md->suspend_lock);
|
|
|
|
/* device must be suspended */
|
|
if (!dm_suspended(md))
|
|
goto out;
|
|
|
|
/* without bdev, the device size cannot be changed */
|
|
if (!md->suspended_bdev)
|
|
if (get_capacity(md->disk) != dm_table_get_size(table))
|
|
goto out;
|
|
|
|
__unbind(md);
|
|
r = __bind(md, table);
|
|
|
|
out:
|
|
mutex_unlock(&md->suspend_lock);
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Functions to lock and unlock any filesystem running on the
|
|
* device.
|
|
*/
|
|
static int lock_fs(struct mapped_device *md)
|
|
{
|
|
int r;
|
|
|
|
WARN_ON(md->frozen_sb);
|
|
|
|
md->frozen_sb = freeze_bdev(md->suspended_bdev);
|
|
if (IS_ERR(md->frozen_sb)) {
|
|
r = PTR_ERR(md->frozen_sb);
|
|
md->frozen_sb = NULL;
|
|
return r;
|
|
}
|
|
|
|
set_bit(DMF_FROZEN, &md->flags);
|
|
|
|
/* don't bdput right now, we don't want the bdev
|
|
* to go away while it is locked.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
static void unlock_fs(struct mapped_device *md)
|
|
{
|
|
if (!test_bit(DMF_FROZEN, &md->flags))
|
|
return;
|
|
|
|
thaw_bdev(md->suspended_bdev, md->frozen_sb);
|
|
md->frozen_sb = NULL;
|
|
clear_bit(DMF_FROZEN, &md->flags);
|
|
}
|
|
|
|
/*
|
|
* We need to be able to change a mapping table under a mounted
|
|
* filesystem. For example we might want to move some data in
|
|
* the background. Before the table can be swapped with
|
|
* dm_bind_table, dm_suspend must be called to flush any in
|
|
* flight bios and ensure that any further io gets deferred.
|
|
*/
|
|
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
|
|
{
|
|
struct dm_table *map = NULL;
|
|
int r = 0;
|
|
int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
|
|
int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
|
|
|
|
mutex_lock(&md->suspend_lock);
|
|
|
|
if (dm_suspended(md)) {
|
|
r = -EINVAL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
map = dm_get_table(md);
|
|
|
|
/*
|
|
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
|
|
* This flag is cleared before dm_suspend returns.
|
|
*/
|
|
if (noflush)
|
|
set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
|
|
|
|
/* This does not get reverted if there's an error later. */
|
|
dm_table_presuspend_targets(map);
|
|
|
|
/* bdget() can stall if the pending I/Os are not flushed */
|
|
if (!noflush) {
|
|
md->suspended_bdev = bdget_disk(md->disk, 0);
|
|
if (!md->suspended_bdev) {
|
|
DMWARN("bdget failed in dm_suspend");
|
|
r = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Flush I/O to the device. noflush supersedes do_lockfs,
|
|
* because lock_fs() needs to flush I/Os.
|
|
*/
|
|
if (do_lockfs) {
|
|
r = lock_fs(md);
|
|
if (r)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Here we must make sure that no processes are submitting requests
|
|
* to target drivers i.e. no one may be executing
|
|
* __split_and_process_bio. This is called from dm_request and
|
|
* dm_wq_work.
|
|
*
|
|
* To get all processes out of __split_and_process_bio in dm_request,
|
|
* we take the write lock. To prevent any process from reentering
|
|
* __split_and_process_bio from dm_request, we set
|
|
* DMF_QUEUE_IO_TO_THREAD.
|
|
*
|
|
* To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND
|
|
* and call flush_workqueue(md->wq). flush_workqueue will wait until
|
|
* dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any
|
|
* further calls to __split_and_process_bio from dm_wq_work.
|
|
*/
|
|
down_write(&md->io_lock);
|
|
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
|
|
set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
|
|
up_write(&md->io_lock);
|
|
|
|
flush_workqueue(md->wq);
|
|
|
|
/*
|
|
* At this point no more requests are entering target request routines.
|
|
* We call dm_wait_for_completion to wait for all existing requests
|
|
* to finish.
|
|
*/
|
|
r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
|
|
|
|
down_write(&md->io_lock);
|
|
if (noflush)
|
|
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
|
|
up_write(&md->io_lock);
|
|
|
|
/* were we interrupted ? */
|
|
if (r < 0) {
|
|
dm_queue_flush(md);
|
|
|
|
unlock_fs(md);
|
|
goto out; /* pushback list is already flushed, so skip flush */
|
|
}
|
|
|
|
/*
|
|
* If dm_wait_for_completion returned 0, the device is completely
|
|
* quiescent now. There is no request-processing activity. All new
|
|
* requests are being added to md->deferred list.
|
|
*/
|
|
|
|
dm_table_postsuspend_targets(map);
|
|
|
|
set_bit(DMF_SUSPENDED, &md->flags);
|
|
|
|
out:
|
|
if (r && md->suspended_bdev) {
|
|
bdput(md->suspended_bdev);
|
|
md->suspended_bdev = NULL;
|
|
}
|
|
|
|
dm_table_put(map);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&md->suspend_lock);
|
|
return r;
|
|
}
|
|
|
|
int dm_resume(struct mapped_device *md)
|
|
{
|
|
int r = -EINVAL;
|
|
struct dm_table *map = NULL;
|
|
|
|
mutex_lock(&md->suspend_lock);
|
|
if (!dm_suspended(md))
|
|
goto out;
|
|
|
|
map = dm_get_table(md);
|
|
if (!map || !dm_table_get_size(map))
|
|
goto out;
|
|
|
|
r = dm_table_resume_targets(map);
|
|
if (r)
|
|
goto out;
|
|
|
|
dm_queue_flush(md);
|
|
|
|
unlock_fs(md);
|
|
|
|
if (md->suspended_bdev) {
|
|
bdput(md->suspended_bdev);
|
|
md->suspended_bdev = NULL;
|
|
}
|
|
|
|
clear_bit(DMF_SUSPENDED, &md->flags);
|
|
|
|
dm_table_unplug_all(map);
|
|
|
|
dm_kobject_uevent(md);
|
|
|
|
r = 0;
|
|
|
|
out:
|
|
dm_table_put(map);
|
|
mutex_unlock(&md->suspend_lock);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Event notification.
|
|
*---------------------------------------------------------------*/
|
|
void dm_kobject_uevent(struct mapped_device *md)
|
|
{
|
|
kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE);
|
|
}
|
|
|
|
uint32_t dm_next_uevent_seq(struct mapped_device *md)
|
|
{
|
|
return atomic_add_return(1, &md->uevent_seq);
|
|
}
|
|
|
|
uint32_t dm_get_event_nr(struct mapped_device *md)
|
|
{
|
|
return atomic_read(&md->event_nr);
|
|
}
|
|
|
|
int dm_wait_event(struct mapped_device *md, int event_nr)
|
|
{
|
|
return wait_event_interruptible(md->eventq,
|
|
(event_nr != atomic_read(&md->event_nr)));
|
|
}
|
|
|
|
void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&md->uevent_lock, flags);
|
|
list_add(elist, &md->uevent_list);
|
|
spin_unlock_irqrestore(&md->uevent_lock, flags);
|
|
}
|
|
|
|
/*
|
|
* The gendisk is only valid as long as you have a reference
|
|
* count on 'md'.
|
|
*/
|
|
struct gendisk *dm_disk(struct mapped_device *md)
|
|
{
|
|
return md->disk;
|
|
}
|
|
|
|
struct kobject *dm_kobject(struct mapped_device *md)
|
|
{
|
|
return &md->kobj;
|
|
}
|
|
|
|
/*
|
|
* struct mapped_device should not be exported outside of dm.c
|
|
* so use this check to verify that kobj is part of md structure
|
|
*/
|
|
struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
|
|
{
|
|
struct mapped_device *md;
|
|
|
|
md = container_of(kobj, struct mapped_device, kobj);
|
|
if (&md->kobj != kobj)
|
|
return NULL;
|
|
|
|
dm_get(md);
|
|
return md;
|
|
}
|
|
|
|
int dm_suspended(struct mapped_device *md)
|
|
{
|
|
return test_bit(DMF_SUSPENDED, &md->flags);
|
|
}
|
|
|
|
int dm_noflush_suspending(struct dm_target *ti)
|
|
{
|
|
struct mapped_device *md = dm_table_get_md(ti->table);
|
|
int r = __noflush_suspending(md);
|
|
|
|
dm_put(md);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_noflush_suspending);
|
|
|
|
static struct block_device_operations dm_blk_dops = {
|
|
.open = dm_blk_open,
|
|
.release = dm_blk_close,
|
|
.ioctl = dm_blk_ioctl,
|
|
.getgeo = dm_blk_getgeo,
|
|
.owner = THIS_MODULE
|
|
};
|
|
|
|
EXPORT_SYMBOL(dm_get_mapinfo);
|
|
|
|
/*
|
|
* module hooks
|
|
*/
|
|
module_init(dm_init);
|
|
module_exit(dm_exit);
|
|
|
|
module_param(major, uint, 0);
|
|
MODULE_PARM_DESC(major, "The major number of the device mapper");
|
|
MODULE_DESCRIPTION(DM_NAME " driver");
|
|
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|
|
|