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152 lines
4.5 KiB
152 lines
4.5 KiB
/* |
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* Copyright (C) 2011-2017 Red Hat, Inc. |
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* |
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* This file is released under the GPL. |
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*/ |
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#ifndef DM_BIO_PRISON_V2_H |
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#define DM_BIO_PRISON_V2_H |
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#include "persistent-data/dm-block-manager.h" /* FIXME: for dm_block_t */ |
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#include "dm-thin-metadata.h" /* FIXME: for dm_thin_id */ |
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#include <linux/bio.h> |
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#include <linux/rbtree.h> |
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#include <linux/workqueue.h> |
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/*----------------------------------------------------------------*/ |
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int dm_bio_prison_init_v2(void); |
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void dm_bio_prison_exit_v2(void); |
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/* |
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* Sometimes we can't deal with a bio straight away. We put them in prison |
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* where they can't cause any mischief. Bios are put in a cell identified |
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* by a key, multiple bios can be in the same cell. When the cell is |
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* subsequently unlocked the bios become available. |
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*/ |
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struct dm_bio_prison_v2; |
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/* |
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* Keys define a range of blocks within either a virtual or physical |
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* device. |
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*/ |
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struct dm_cell_key_v2 { |
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int virtual; |
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dm_thin_id dev; |
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dm_block_t block_begin, block_end; |
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}; |
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/* |
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* Treat this as opaque, only in header so callers can manage allocation |
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* themselves. |
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*/ |
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struct dm_bio_prison_cell_v2 { |
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// FIXME: pack these |
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bool exclusive_lock; |
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unsigned exclusive_level; |
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unsigned shared_count; |
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struct work_struct *quiesce_continuation; |
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struct rb_node node; |
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struct dm_cell_key_v2 key; |
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struct bio_list bios; |
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}; |
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struct dm_bio_prison_v2 *dm_bio_prison_create_v2(struct workqueue_struct *wq); |
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void dm_bio_prison_destroy_v2(struct dm_bio_prison_v2 *prison); |
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/* |
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* These two functions just wrap a mempool. This is a transitory step: |
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* Eventually all bio prison clients should manage their own cell memory. |
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* |
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* Like mempool_alloc(), dm_bio_prison_alloc_cell_v2() can only fail if called |
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* in interrupt context or passed GFP_NOWAIT. |
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*/ |
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struct dm_bio_prison_cell_v2 *dm_bio_prison_alloc_cell_v2(struct dm_bio_prison_v2 *prison, |
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gfp_t gfp); |
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void dm_bio_prison_free_cell_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_bio_prison_cell_v2 *cell); |
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/* |
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* Shared locks have a bio associated with them. |
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* |
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* If the lock is granted the caller can continue to use the bio, and must |
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* call dm_cell_put_v2() to drop the reference count when finished using it. |
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* |
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* If the lock cannot be granted then the bio will be tracked within the |
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* cell, and later given to the holder of the exclusive lock. |
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* |
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* See dm_cell_lock_v2() for discussion of the lock_level parameter. |
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* |
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* Compare *cell_result with cell_prealloc to see if the prealloc was used. |
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* If cell_prealloc was used then inmate wasn't added to it. |
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* |
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* Returns true if the lock is granted. |
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*/ |
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bool dm_cell_get_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_cell_key_v2 *key, |
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unsigned lock_level, |
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struct bio *inmate, |
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struct dm_bio_prison_cell_v2 *cell_prealloc, |
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struct dm_bio_prison_cell_v2 **cell_result); |
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/* |
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* Decrement the shared reference count for the lock. Returns true if |
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* returning ownership of the cell (ie. you should free it). |
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*/ |
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bool dm_cell_put_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_bio_prison_cell_v2 *cell); |
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/* |
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* Locks a cell. No associated bio. Exclusive locks get priority. These |
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* locks constrain whether the io locks are granted according to level. |
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* |
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* Shared locks will still be granted if the lock_level is > (not = to) the |
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* exclusive lock level. |
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* |
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* If an _exclusive_ lock is already held then -EBUSY is returned. |
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* |
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* Return values: |
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* < 0 - error |
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* 0 - locked; no quiescing needed |
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* 1 - locked; quiescing needed |
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*/ |
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int dm_cell_lock_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_cell_key_v2 *key, |
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unsigned lock_level, |
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struct dm_bio_prison_cell_v2 *cell_prealloc, |
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struct dm_bio_prison_cell_v2 **cell_result); |
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void dm_cell_quiesce_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_bio_prison_cell_v2 *cell, |
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struct work_struct *continuation); |
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/* |
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* Promotes an _exclusive_ lock to a higher lock level. |
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* |
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* Return values: |
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* < 0 - error |
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* 0 - promoted; no quiescing needed |
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* 1 - promoted; quiescing needed |
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*/ |
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int dm_cell_lock_promote_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_bio_prison_cell_v2 *cell, |
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unsigned new_lock_level); |
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/* |
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* Adds any held bios to the bio list. |
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* |
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* There may be shared locks still held at this point even if you quiesced |
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* (ie. different lock levels). |
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* |
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* Returns true if returning ownership of the cell (ie. you should free |
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* it). |
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*/ |
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bool dm_cell_unlock_v2(struct dm_bio_prison_v2 *prison, |
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struct dm_bio_prison_cell_v2 *cell, |
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struct bio_list *bios); |
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/*----------------------------------------------------------------*/ |
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#endif
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