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1197 lines
23 KiB
1197 lines
23 KiB
/*
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* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
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* Copyright (C) 2004 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-bio-list.h"
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#include <linux/init.h>
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#include <linux/module.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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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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/*
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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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struct bio *bio;
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atomic_t io_count;
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};
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/*
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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 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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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 target_io *)bio->bi_private)->info;
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return NULL;
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}
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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 0
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#define DMF_SUSPENDED 1
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struct mapped_device {
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struct rw_semaphore io_lock;
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struct semaphore suspend_lock;
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rwlock_t map_lock;
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atomic_t holders;
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unsigned long flags;
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request_queue_t *queue;
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struct gendisk *disk;
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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 bio_list deferred;
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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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/*
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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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/*
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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 *frozen_bdev;
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};
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#define MIN_IOS 256
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static kmem_cache_t *_io_cache;
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static kmem_cache_t *_tio_cache;
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static struct bio_set *dm_set;
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static int __init local_init(void)
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{
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int r;
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dm_set = bioset_create(16, 16, 4);
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if (!dm_set)
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return -ENOMEM;
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/* allocate a slab for the dm_ios */
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_io_cache = kmem_cache_create("dm_io",
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sizeof(struct dm_io), 0, 0, NULL, NULL);
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if (!_io_cache)
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return -ENOMEM;
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/* allocate a slab for the target ios */
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_tio_cache = kmem_cache_create("dm_tio", sizeof(struct target_io),
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0, 0, NULL, NULL);
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if (!_tio_cache) {
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kmem_cache_destroy(_io_cache);
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return -ENOMEM;
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}
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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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kmem_cache_destroy(_tio_cache);
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kmem_cache_destroy(_io_cache);
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return r;
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}
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if (!_major)
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_major = r;
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return 0;
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}
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static void local_exit(void)
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{
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kmem_cache_destroy(_tio_cache);
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kmem_cache_destroy(_io_cache);
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bioset_free(dm_set);
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if (unregister_blkdev(_major, _name) < 0)
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DMERR("devfs_unregister_blkdev failed");
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_major = 0;
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DMINFO("cleaned up");
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}
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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_interface_init,
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};
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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_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 inode *inode, struct file *file)
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{
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struct mapped_device *md;
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md = inode->i_bdev->bd_disk->private_data;
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dm_get(md);
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return 0;
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}
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static int dm_blk_close(struct inode *inode, struct file *file)
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{
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struct mapped_device *md;
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md = inode->i_bdev->bd_disk->private_data;
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dm_put(md);
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return 0;
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}
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static inline 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 inline 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 inline struct 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 inline void free_tio(struct mapped_device *md, struct 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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/*
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* Add the bio to the list of deferred io.
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*/
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static int 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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if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
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up_write(&md->io_lock);
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return 1;
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}
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bio_list_add(&md->deferred, bio);
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up_write(&md->io_lock);
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return 0; /* deferred successfully */
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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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* CRUD START:
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* A more elegant soln is in the works that uses the queue
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* 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
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* interests of getting something for people to use I give
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* you this clearly demarcated crap.
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*---------------------------------------------------------------*/
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/*
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* Decrements the number of outstanding ios that a bio has been
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* cloned into, completing the original io if necc.
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*/
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static inline void dec_pending(struct dm_io *io, int error)
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{
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if (error)
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io->error = error;
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if (atomic_dec_and_test(&io->io_count)) {
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if (atomic_dec_and_test(&io->md->pending))
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/* nudge anyone waiting on suspend queue */
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wake_up(&io->md->wait);
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bio_endio(io->bio, io->bio->bi_size, io->error);
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free_io(io->md, io);
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}
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}
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static int clone_endio(struct bio *bio, unsigned int done, int error)
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{
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int r = 0;
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struct target_io *tio = bio->bi_private;
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struct dm_io *io = tio->io;
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dm_endio_fn endio = tio->ti->type->end_io;
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if (bio->bi_size)
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return 1;
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if (!bio_flagged(bio, BIO_UPTODATE) && !error)
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error = -EIO;
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if (endio) {
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r = endio(tio->ti, bio, error, &tio->info);
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if (r < 0)
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error = r;
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else if (r > 0)
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/* the target wants another shot at the io */
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return 1;
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}
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free_tio(io->md, tio);
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dec_pending(io, error);
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bio_put(bio);
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return r;
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}
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static sector_t max_io_len(struct mapped_device *md,
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sector_t sector, struct dm_target *ti)
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{
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sector_t offset = sector - ti->begin;
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sector_t len = ti->len - offset;
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/*
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* Does the target need to split even further ?
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*/
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if (ti->split_io) {
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sector_t boundary;
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boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
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- offset;
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if (len > boundary)
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len = boundary;
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}
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return len;
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}
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static void __map_bio(struct dm_target *ti, struct bio *clone,
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struct target_io *tio)
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{
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int r;
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/*
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* Sanity checks.
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*/
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BUG_ON(!clone->bi_size);
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clone->bi_end_io = clone_endio;
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clone->bi_private = tio;
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/*
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* Map the clone. If r == 0 we don't need to do
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* anything, the target has assumed ownership of
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* this io.
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*/
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atomic_inc(&tio->io->io_count);
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r = ti->type->map(ti, clone, &tio->info);
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if (r > 0)
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/* the bio has been remapped so dispatch it */
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generic_make_request(clone);
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else if (r < 0) {
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/* error the io and bail out */
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struct dm_io *io = tio->io;
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free_tio(tio->io->md, tio);
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dec_pending(io, r);
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bio_put(clone);
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}
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}
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struct clone_info {
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struct mapped_device *md;
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struct dm_table *map;
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struct bio *bio;
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struct dm_io *io;
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sector_t sector;
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sector_t sector_count;
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unsigned short idx;
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};
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static void dm_bio_destructor(struct bio *bio)
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{
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bio_free(bio, dm_set);
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}
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/*
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* Creates a little bio that is just does part of a bvec.
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*/
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static struct bio *split_bvec(struct bio *bio, sector_t sector,
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unsigned short idx, unsigned int offset,
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unsigned int len)
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{
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struct bio *clone;
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struct bio_vec *bv = bio->bi_io_vec + idx;
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clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set);
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clone->bi_destructor = dm_bio_destructor;
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*clone->bi_io_vec = *bv;
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clone->bi_sector = sector;
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clone->bi_bdev = bio->bi_bdev;
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clone->bi_rw = bio->bi_rw;
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clone->bi_vcnt = 1;
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clone->bi_size = to_bytes(len);
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clone->bi_io_vec->bv_offset = offset;
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clone->bi_io_vec->bv_len = clone->bi_size;
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return clone;
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}
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/*
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* Creates a bio that consists of range of complete bvecs.
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*/
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static struct bio *clone_bio(struct bio *bio, sector_t sector,
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unsigned short idx, unsigned short bv_count,
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unsigned int len)
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{
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struct bio *clone;
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clone = bio_clone(bio, GFP_NOIO);
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clone->bi_sector = sector;
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clone->bi_idx = idx;
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clone->bi_vcnt = idx + bv_count;
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clone->bi_size = to_bytes(len);
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clone->bi_flags &= ~(1 << BIO_SEG_VALID);
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return clone;
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}
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static void __clone_and_map(struct clone_info *ci)
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{
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struct bio *clone, *bio = ci->bio;
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struct dm_target *ti = dm_table_find_target(ci->map, ci->sector);
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sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti);
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struct target_io *tio;
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/*
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* Allocate a target io object.
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*/
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tio = alloc_tio(ci->md);
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tio->io = ci->io;
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tio->ti = ti;
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memset(&tio->info, 0, sizeof(tio->info));
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if (ci->sector_count <= max) {
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/*
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* Optimise for the simple case where we can do all of
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* the remaining io with a single clone.
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*/
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clone = clone_bio(bio, ci->sector, ci->idx,
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bio->bi_vcnt - ci->idx, ci->sector_count);
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__map_bio(ti, clone, tio);
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ci->sector_count = 0;
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} else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
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/*
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* There are some bvecs that don't span targets.
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* Do as many of these as possible.
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*/
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int i;
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sector_t remaining = max;
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sector_t bv_len;
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for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
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bv_len = to_sector(bio->bi_io_vec[i].bv_len);
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|
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if (bv_len > remaining)
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break;
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remaining -= bv_len;
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len += bv_len;
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}
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clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len);
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__map_bio(ti, clone, tio);
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ci->sector += len;
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ci->sector_count -= len;
|
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ci->idx = i;
|
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|
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} else {
|
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/*
|
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* Create two copy bios to deal with io that has
|
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* been split across a target.
|
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*/
|
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struct bio_vec *bv = bio->bi_io_vec + ci->idx;
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|
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clone = split_bvec(bio, ci->sector, ci->idx,
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bv->bv_offset, max);
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__map_bio(ti, clone, tio);
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|
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ci->sector += max;
|
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ci->sector_count -= max;
|
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ti = dm_table_find_target(ci->map, ci->sector);
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|
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len = to_sector(bv->bv_len) - max;
|
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clone = split_bvec(bio, ci->sector, ci->idx,
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bv->bv_offset + to_bytes(max), len);
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tio = alloc_tio(ci->md);
|
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tio->io = ci->io;
|
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tio->ti = ti;
|
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memset(&tio->info, 0, sizeof(tio->info));
|
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__map_bio(ti, clone, tio);
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|
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ci->sector += len;
|
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ci->sector_count -= len;
|
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ci->idx++;
|
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}
|
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}
|
|
|
|
/*
|
|
* Split the bio into several clones.
|
|
*/
|
|
static void __split_bio(struct mapped_device *md, struct bio *bio)
|
|
{
|
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struct clone_info ci;
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|
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ci.map = dm_get_table(md);
|
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if (!ci.map) {
|
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bio_io_error(bio, bio->bi_size);
|
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return;
|
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}
|
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|
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ci.md = md;
|
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ci.bio = bio;
|
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ci.io = alloc_io(md);
|
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ci.io->error = 0;
|
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atomic_set(&ci.io->io_count, 1);
|
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ci.io->bio = bio;
|
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ci.io->md = md;
|
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ci.sector = bio->bi_sector;
|
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ci.sector_count = bio_sectors(bio);
|
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ci.idx = bio->bi_idx;
|
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|
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atomic_inc(&md->pending);
|
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while (ci.sector_count)
|
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__clone_and_map(&ci);
|
|
|
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/* drop the extra reference count */
|
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dec_pending(ci.io, 0);
|
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dm_table_put(ci.map);
|
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}
|
|
/*-----------------------------------------------------------------
|
|
* CRUD END
|
|
*---------------------------------------------------------------*/
|
|
|
|
/*
|
|
* The request function that just remaps the bio built up by
|
|
* dm_merge_bvec.
|
|
*/
|
|
static int dm_request(request_queue_t *q, struct bio *bio)
|
|
{
|
|
int r;
|
|
struct mapped_device *md = q->queuedata;
|
|
|
|
down_read(&md->io_lock);
|
|
|
|
/*
|
|
* If we're suspended we have to queue
|
|
* this io for later.
|
|
*/
|
|
while (test_bit(DMF_BLOCK_IO, &md->flags)) {
|
|
up_read(&md->io_lock);
|
|
|
|
if (bio_rw(bio) == READA) {
|
|
bio_io_error(bio, bio->bi_size);
|
|
return 0;
|
|
}
|
|
|
|
r = queue_io(md, bio);
|
|
if (r < 0) {
|
|
bio_io_error(bio, bio->bi_size);
|
|
return 0;
|
|
|
|
} else if (r == 0)
|
|
return 0; /* deferred successfully */
|
|
|
|
/*
|
|
* We're in a while loop, because someone could suspend
|
|
* before we get to the following read lock.
|
|
*/
|
|
down_read(&md->io_lock);
|
|
}
|
|
|
|
__split_bio(md, bio);
|
|
up_read(&md->io_lock);
|
|
return 0;
|
|
}
|
|
|
|
static int dm_flush_all(request_queue_t *q, struct gendisk *disk,
|
|
sector_t *error_sector)
|
|
{
|
|
struct mapped_device *md = q->queuedata;
|
|
struct dm_table *map = dm_get_table(md);
|
|
int ret = -ENXIO;
|
|
|
|
if (map) {
|
|
ret = dm_table_flush_all(map);
|
|
dm_table_put(map);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void dm_unplug_all(request_queue_t *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;
|
|
struct mapped_device *md = (struct mapped_device *) congested_data;
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
if (!map || test_bit(DMF_BLOCK_IO, &md->flags))
|
|
r = bdi_bits;
|
|
else
|
|
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 DECLARE_MUTEX(_minor_lock);
|
|
static DEFINE_IDR(_minor_idr);
|
|
|
|
static void free_minor(unsigned int minor)
|
|
{
|
|
down(&_minor_lock);
|
|
idr_remove(&_minor_idr, minor);
|
|
up(&_minor_lock);
|
|
}
|
|
|
|
/*
|
|
* See if the device with a specific minor # is free.
|
|
*/
|
|
static int specific_minor(struct mapped_device *md, unsigned int minor)
|
|
{
|
|
int r, m;
|
|
|
|
if (minor >= (1 << MINORBITS))
|
|
return -EINVAL;
|
|
|
|
down(&_minor_lock);
|
|
|
|
if (idr_find(&_minor_idr, minor)) {
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
|
|
if (!r) {
|
|
r = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_get_new_above(&_minor_idr, md, minor, &m);
|
|
if (r) {
|
|
goto out;
|
|
}
|
|
|
|
if (m != minor) {
|
|
idr_remove(&_minor_idr, m);
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
up(&_minor_lock);
|
|
return r;
|
|
}
|
|
|
|
static int next_free_minor(struct mapped_device *md, unsigned int *minor)
|
|
{
|
|
int r;
|
|
unsigned int m;
|
|
|
|
down(&_minor_lock);
|
|
|
|
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
|
|
if (!r) {
|
|
r = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_get_new(&_minor_idr, md, &m);
|
|
if (r) {
|
|
goto out;
|
|
}
|
|
|
|
if (m >= (1 << MINORBITS)) {
|
|
idr_remove(&_minor_idr, m);
|
|
r = -ENOSPC;
|
|
goto out;
|
|
}
|
|
|
|
*minor = m;
|
|
|
|
out:
|
|
up(&_minor_lock);
|
|
return r;
|
|
}
|
|
|
|
static struct block_device_operations dm_blk_dops;
|
|
|
|
/*
|
|
* Allocate and initialise a blank device with a given minor.
|
|
*/
|
|
static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
|
|
{
|
|
int r;
|
|
struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
|
|
|
|
if (!md) {
|
|
DMWARN("unable to allocate device, out of memory.");
|
|
return NULL;
|
|
}
|
|
|
|
/* get a minor number for the dev */
|
|
r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor);
|
|
if (r < 0)
|
|
goto bad1;
|
|
|
|
memset(md, 0, sizeof(*md));
|
|
init_rwsem(&md->io_lock);
|
|
init_MUTEX(&md->suspend_lock);
|
|
rwlock_init(&md->map_lock);
|
|
atomic_set(&md->holders, 1);
|
|
atomic_set(&md->event_nr, 0);
|
|
|
|
md->queue = blk_alloc_queue(GFP_KERNEL);
|
|
if (!md->queue)
|
|
goto bad1;
|
|
|
|
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);
|
|
md->queue->unplug_fn = dm_unplug_all;
|
|
md->queue->issue_flush_fn = dm_flush_all;
|
|
|
|
md->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
|
|
mempool_free_slab, _io_cache);
|
|
if (!md->io_pool)
|
|
goto bad2;
|
|
|
|
md->tio_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
|
|
mempool_free_slab, _tio_cache);
|
|
if (!md->tio_pool)
|
|
goto bad3;
|
|
|
|
md->disk = alloc_disk(1);
|
|
if (!md->disk)
|
|
goto bad4;
|
|
|
|
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);
|
|
|
|
atomic_set(&md->pending, 0);
|
|
init_waitqueue_head(&md->wait);
|
|
init_waitqueue_head(&md->eventq);
|
|
|
|
return md;
|
|
|
|
bad4:
|
|
mempool_destroy(md->tio_pool);
|
|
bad3:
|
|
mempool_destroy(md->io_pool);
|
|
bad2:
|
|
blk_put_queue(md->queue);
|
|
free_minor(minor);
|
|
bad1:
|
|
kfree(md);
|
|
return NULL;
|
|
}
|
|
|
|
static void free_dev(struct mapped_device *md)
|
|
{
|
|
free_minor(md->disk->first_minor);
|
|
mempool_destroy(md->tio_pool);
|
|
mempool_destroy(md->io_pool);
|
|
del_gendisk(md->disk);
|
|
put_disk(md->disk);
|
|
blk_put_queue(md->queue);
|
|
kfree(md);
|
|
}
|
|
|
|
/*
|
|
* Bind a table to the device.
|
|
*/
|
|
static void event_callback(void *context)
|
|
{
|
|
struct mapped_device *md = (struct mapped_device *) context;
|
|
|
|
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);
|
|
|
|
down(&md->frozen_bdev->bd_inode->i_sem);
|
|
i_size_write(md->frozen_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
|
|
up(&md->frozen_bdev->bd_inode->i_sem);
|
|
}
|
|
|
|
static int __bind(struct mapped_device *md, struct dm_table *t)
|
|
{
|
|
request_queue_t *q = md->queue;
|
|
sector_t size;
|
|
|
|
size = dm_table_get_size(t);
|
|
__set_size(md, size);
|
|
if (size == 0)
|
|
return 0;
|
|
|
|
dm_table_get(t);
|
|
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_put(map);
|
|
}
|
|
|
|
/*
|
|
* Constructor for a new device.
|
|
*/
|
|
static int create_aux(unsigned int minor, int persistent,
|
|
struct mapped_device **result)
|
|
{
|
|
struct mapped_device *md;
|
|
|
|
md = alloc_dev(minor, persistent);
|
|
if (!md)
|
|
return -ENXIO;
|
|
|
|
*result = md;
|
|
return 0;
|
|
}
|
|
|
|
int dm_create(struct mapped_device **result)
|
|
{
|
|
return create_aux(0, 0, result);
|
|
}
|
|
|
|
int dm_create_with_minor(unsigned int minor, struct mapped_device **result)
|
|
{
|
|
return create_aux(minor, 1, result);
|
|
}
|
|
|
|
void *dm_get_mdptr(dev_t dev)
|
|
{
|
|
struct mapped_device *md;
|
|
void *mdptr = NULL;
|
|
unsigned minor = MINOR(dev);
|
|
|
|
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
|
|
return NULL;
|
|
|
|
down(&_minor_lock);
|
|
|
|
md = idr_find(&_minor_idr, minor);
|
|
|
|
if (md && (dm_disk(md)->first_minor == minor))
|
|
mdptr = md->interface_ptr;
|
|
|
|
up(&_minor_lock);
|
|
|
|
return mdptr;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
void dm_put(struct mapped_device *md)
|
|
{
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
if (atomic_dec_and_test(&md->holders)) {
|
|
if (!dm_suspended(md)) {
|
|
dm_table_presuspend_targets(map);
|
|
dm_table_postsuspend_targets(map);
|
|
}
|
|
__unbind(md);
|
|
free_dev(md);
|
|
}
|
|
|
|
dm_table_put(map);
|
|
}
|
|
|
|
/*
|
|
* Process the deferred bios
|
|
*/
|
|
static void __flush_deferred_io(struct mapped_device *md, struct bio *c)
|
|
{
|
|
struct bio *n;
|
|
|
|
while (c) {
|
|
n = c->bi_next;
|
|
c->bi_next = NULL;
|
|
__split_bio(md, c);
|
|
c = n;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Swap in a new table (destroying old one).
|
|
*/
|
|
int dm_swap_table(struct mapped_device *md, struct dm_table *table)
|
|
{
|
|
int r = -EINVAL;
|
|
|
|
down(&md->suspend_lock);
|
|
|
|
/* device must be suspended */
|
|
if (!dm_suspended(md))
|
|
goto out;
|
|
|
|
__unbind(md);
|
|
r = __bind(md, table);
|
|
|
|
out:
|
|
up(&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 = -ENOMEM;
|
|
|
|
md->frozen_bdev = bdget_disk(md->disk, 0);
|
|
if (!md->frozen_bdev) {
|
|
DMWARN("bdget failed in lock_fs");
|
|
goto out;
|
|
}
|
|
|
|
WARN_ON(md->frozen_sb);
|
|
|
|
md->frozen_sb = freeze_bdev(md->frozen_bdev);
|
|
if (IS_ERR(md->frozen_sb)) {
|
|
r = PTR_ERR(md->frozen_sb);
|
|
goto out_bdput;
|
|
}
|
|
|
|
/* don't bdput right now, we don't want the bdev
|
|
* to go away while it is locked. We'll bdput
|
|
* in unlock_fs
|
|
*/
|
|
return 0;
|
|
|
|
out_bdput:
|
|
bdput(md->frozen_bdev);
|
|
md->frozen_sb = NULL;
|
|
md->frozen_bdev = NULL;
|
|
out:
|
|
return r;
|
|
}
|
|
|
|
static void unlock_fs(struct mapped_device *md)
|
|
{
|
|
thaw_bdev(md->frozen_bdev, md->frozen_sb);
|
|
bdput(md->frozen_bdev);
|
|
|
|
md->frozen_sb = NULL;
|
|
md->frozen_bdev = NULL;
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct dm_table *map = NULL;
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
int r = -EINVAL;
|
|
|
|
down(&md->suspend_lock);
|
|
|
|
if (dm_suspended(md))
|
|
goto out;
|
|
|
|
map = dm_get_table(md);
|
|
|
|
/* This does not get reverted if there's an error later. */
|
|
dm_table_presuspend_targets(map);
|
|
|
|
/* Flush I/O to the device. */
|
|
r = lock_fs(md);
|
|
if (r)
|
|
goto out;
|
|
|
|
/*
|
|
* First we set the BLOCK_IO flag so no more ios will be mapped.
|
|
*/
|
|
down_write(&md->io_lock);
|
|
set_bit(DMF_BLOCK_IO, &md->flags);
|
|
|
|
add_wait_queue(&md->wait, &wait);
|
|
up_write(&md->io_lock);
|
|
|
|
/* unplug */
|
|
if (map)
|
|
dm_table_unplug_all(map);
|
|
|
|
/*
|
|
* Then we wait for the already mapped ios to
|
|
* complete.
|
|
*/
|
|
while (1) {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
if (!atomic_read(&md->pending) || signal_pending(current))
|
|
break;
|
|
|
|
io_schedule();
|
|
}
|
|
set_current_state(TASK_RUNNING);
|
|
|
|
down_write(&md->io_lock);
|
|
remove_wait_queue(&md->wait, &wait);
|
|
|
|
/* were we interrupted ? */
|
|
r = -EINTR;
|
|
if (atomic_read(&md->pending)) {
|
|
up_write(&md->io_lock);
|
|
unlock_fs(md);
|
|
clear_bit(DMF_BLOCK_IO, &md->flags);
|
|
goto out;
|
|
}
|
|
up_write(&md->io_lock);
|
|
|
|
dm_table_postsuspend_targets(map);
|
|
|
|
set_bit(DMF_SUSPENDED, &md->flags);
|
|
|
|
r = 0;
|
|
|
|
out:
|
|
dm_table_put(map);
|
|
up(&md->suspend_lock);
|
|
return r;
|
|
}
|
|
|
|
int dm_resume(struct mapped_device *md)
|
|
{
|
|
int r = -EINVAL;
|
|
struct bio *def;
|
|
struct dm_table *map = NULL;
|
|
|
|
down(&md->suspend_lock);
|
|
if (!dm_suspended(md))
|
|
goto out;
|
|
|
|
map = dm_get_table(md);
|
|
if (!map || !dm_table_get_size(map))
|
|
goto out;
|
|
|
|
dm_table_resume_targets(map);
|
|
|
|
down_write(&md->io_lock);
|
|
clear_bit(DMF_BLOCK_IO, &md->flags);
|
|
|
|
def = bio_list_get(&md->deferred);
|
|
__flush_deferred_io(md, def);
|
|
up_write(&md->io_lock);
|
|
|
|
unlock_fs(md);
|
|
|
|
clear_bit(DMF_SUSPENDED, &md->flags);
|
|
|
|
dm_table_unplug_all(map);
|
|
|
|
r = 0;
|
|
|
|
out:
|
|
dm_table_put(map);
|
|
up(&md->suspend_lock);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Event notification.
|
|
*---------------------------------------------------------------*/
|
|
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)));
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
int dm_suspended(struct mapped_device *md)
|
|
{
|
|
return test_bit(DMF_SUSPENDED, &md->flags);
|
|
}
|
|
|
|
static struct block_device_operations dm_blk_dops = {
|
|
.open = dm_blk_open,
|
|
.release = dm_blk_close,
|
|
.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");
|
|
|