154 lines
4.6 KiB
C
154 lines
4.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Copyright (C) 2011-2017 Red Hat, Inc.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#ifndef DM_BIO_PRISON_V2_H
|
|
#define DM_BIO_PRISON_V2_H
|
|
|
|
#include "persistent-data/dm-block-manager.h" /* FIXME: for dm_block_t */
|
|
#include "dm-thin-metadata.h" /* FIXME: for dm_thin_id */
|
|
|
|
#include <linux/bio.h>
|
|
#include <linux/rbtree.h>
|
|
#include <linux/workqueue.h>
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
int dm_bio_prison_init_v2(void);
|
|
void dm_bio_prison_exit_v2(void);
|
|
|
|
/*
|
|
* Sometimes we can't deal with a bio straight away. We put them in prison
|
|
* where they can't cause any mischief. Bios are put in a cell identified
|
|
* by a key, multiple bios can be in the same cell. When the cell is
|
|
* subsequently unlocked the bios become available.
|
|
*/
|
|
struct dm_bio_prison_v2;
|
|
|
|
/*
|
|
* Keys define a range of blocks within either a virtual or physical
|
|
* device.
|
|
*/
|
|
struct dm_cell_key_v2 {
|
|
int virtual;
|
|
dm_thin_id dev;
|
|
dm_block_t block_begin, block_end;
|
|
};
|
|
|
|
/*
|
|
* Treat this as opaque, only in header so callers can manage allocation
|
|
* themselves.
|
|
*/
|
|
struct dm_bio_prison_cell_v2 {
|
|
// FIXME: pack these
|
|
bool exclusive_lock;
|
|
unsigned int exclusive_level;
|
|
unsigned int shared_count;
|
|
struct work_struct *quiesce_continuation;
|
|
|
|
struct rb_node node;
|
|
struct dm_cell_key_v2 key;
|
|
struct bio_list bios;
|
|
};
|
|
|
|
struct dm_bio_prison_v2 *dm_bio_prison_create_v2(struct workqueue_struct *wq);
|
|
void dm_bio_prison_destroy_v2(struct dm_bio_prison_v2 *prison);
|
|
|
|
/*
|
|
* These two functions just wrap a mempool. This is a transitory step:
|
|
* Eventually all bio prison clients should manage their own cell memory.
|
|
*
|
|
* Like mempool_alloc(), dm_bio_prison_alloc_cell_v2() can only fail if called
|
|
* in interrupt context or passed GFP_NOWAIT.
|
|
*/
|
|
struct dm_bio_prison_cell_v2 *dm_bio_prison_alloc_cell_v2(struct dm_bio_prison_v2 *prison,
|
|
gfp_t gfp);
|
|
void dm_bio_prison_free_cell_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_bio_prison_cell_v2 *cell);
|
|
|
|
/*
|
|
* Shared locks have a bio associated with them.
|
|
*
|
|
* If the lock is granted the caller can continue to use the bio, and must
|
|
* call dm_cell_put_v2() to drop the reference count when finished using it.
|
|
*
|
|
* If the lock cannot be granted then the bio will be tracked within the
|
|
* cell, and later given to the holder of the exclusive lock.
|
|
*
|
|
* See dm_cell_lock_v2() for discussion of the lock_level parameter.
|
|
*
|
|
* Compare *cell_result with cell_prealloc to see if the prealloc was used.
|
|
* If cell_prealloc was used then inmate wasn't added to it.
|
|
*
|
|
* Returns true if the lock is granted.
|
|
*/
|
|
bool dm_cell_get_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_cell_key_v2 *key,
|
|
unsigned int lock_level,
|
|
struct bio *inmate,
|
|
struct dm_bio_prison_cell_v2 *cell_prealloc,
|
|
struct dm_bio_prison_cell_v2 **cell_result);
|
|
|
|
/*
|
|
* Decrement the shared reference count for the lock. Returns true if
|
|
* returning ownership of the cell (ie. you should free it).
|
|
*/
|
|
bool dm_cell_put_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_bio_prison_cell_v2 *cell);
|
|
|
|
/*
|
|
* Locks a cell. No associated bio. Exclusive locks get priority. These
|
|
* locks constrain whether the io locks are granted according to level.
|
|
*
|
|
* Shared locks will still be granted if the lock_level is > (not = to) the
|
|
* exclusive lock level.
|
|
*
|
|
* If an _exclusive_ lock is already held then -EBUSY is returned.
|
|
*
|
|
* Return values:
|
|
* < 0 - error
|
|
* 0 - locked; no quiescing needed
|
|
* 1 - locked; quiescing needed
|
|
*/
|
|
int dm_cell_lock_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_cell_key_v2 *key,
|
|
unsigned int lock_level,
|
|
struct dm_bio_prison_cell_v2 *cell_prealloc,
|
|
struct dm_bio_prison_cell_v2 **cell_result);
|
|
|
|
void dm_cell_quiesce_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_bio_prison_cell_v2 *cell,
|
|
struct work_struct *continuation);
|
|
|
|
/*
|
|
* Promotes an _exclusive_ lock to a higher lock level.
|
|
*
|
|
* Return values:
|
|
* < 0 - error
|
|
* 0 - promoted; no quiescing needed
|
|
* 1 - promoted; quiescing needed
|
|
*/
|
|
int dm_cell_lock_promote_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_bio_prison_cell_v2 *cell,
|
|
unsigned int new_lock_level);
|
|
|
|
/*
|
|
* Adds any held bios to the bio list.
|
|
*
|
|
* There may be shared locks still held at this point even if you quiesced
|
|
* (ie. different lock levels).
|
|
*
|
|
* Returns true if returning ownership of the cell (ie. you should free
|
|
* it).
|
|
*/
|
|
bool dm_cell_unlock_v2(struct dm_bio_prison_v2 *prison,
|
|
struct dm_bio_prison_cell_v2 *cell,
|
|
struct bio_list *bios);
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
#endif
|