4a0b4ddf26
Change bio-based mapped devices no longer to have a fully initialized
request_queue (request_fn, elevator, etc). This means bio-based DM
devices no longer register elevator sysfs attributes ('iosched/' tree
or 'scheduler' other than "none").
In contrast, a request-based DM device will continue to have a full
request_queue and will register elevator sysfs attributes. Therefore
a user can determine a DM device's type by checking if elevator sysfs
attributes exist.
First allocate a minimalist request_queue structure for a DM device
(needed for both bio and request-based DM).
Initialization of a full request_queue is deferred until it is known
that the DM device is request-based, at the end of the table load
sequence.
Factor DM device's request_queue initialization:
- common to both request-based and bio-based into dm_init_md_queue().
- specific to request-based into dm_init_request_based_queue().
The md->type_lock mutex is used to protect md->queue, in addition to
md->type, during table_load().
A DM device's first table_load will establish the immutable md->type.
But md->queue initialization, based on md->type, may fail at that time
(because blk_init_allocated_queue cannot allocate memory). Therefore
any subsequent table_load must (re)try dm_setup_md_queue independently of
establishing md->type.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
156 lines
4.4 KiB
C
156 lines
4.4 KiB
C
/*
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* Internal header file for device mapper
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*
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* Copyright (C) 2001, 2002 Sistina Software
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef DM_INTERNAL_H
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#define DM_INTERNAL_H
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#include <linux/fs.h>
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#include <linux/device-mapper.h>
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#include <linux/list.h>
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#include <linux/blkdev.h>
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#include <linux/hdreg.h>
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/*
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* Suspend feature flags
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*/
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#define DM_SUSPEND_LOCKFS_FLAG (1 << 0)
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#define DM_SUSPEND_NOFLUSH_FLAG (1 << 1)
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/*
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* Type of table and mapped_device's mempool
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*/
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#define DM_TYPE_NONE 0
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#define DM_TYPE_BIO_BASED 1
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#define DM_TYPE_REQUEST_BASED 2
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/*
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* List of devices that a metadevice uses and should open/close.
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*/
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struct dm_dev_internal {
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struct list_head list;
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atomic_t count;
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struct dm_dev dm_dev;
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};
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struct dm_table;
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struct dm_md_mempools;
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/*-----------------------------------------------------------------
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* Internal table functions.
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*---------------------------------------------------------------*/
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void dm_table_destroy(struct dm_table *t);
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void dm_table_event_callback(struct dm_table *t,
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void (*fn)(void *), void *context);
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struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
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struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
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int dm_calculate_queue_limits(struct dm_table *table,
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struct queue_limits *limits);
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void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
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struct queue_limits *limits);
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struct list_head *dm_table_get_devices(struct dm_table *t);
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void dm_table_presuspend_targets(struct dm_table *t);
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void dm_table_postsuspend_targets(struct dm_table *t);
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int dm_table_resume_targets(struct dm_table *t);
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int dm_table_any_congested(struct dm_table *t, int bdi_bits);
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int dm_table_any_busy_target(struct dm_table *t);
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int dm_table_set_type(struct dm_table *t);
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unsigned dm_table_get_type(struct dm_table *t);
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bool dm_table_request_based(struct dm_table *t);
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int dm_table_alloc_md_mempools(struct dm_table *t);
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void dm_table_free_md_mempools(struct dm_table *t);
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struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
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void dm_lock_md_type(struct mapped_device *md);
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void dm_unlock_md_type(struct mapped_device *md);
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void dm_set_md_type(struct mapped_device *md, unsigned type);
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unsigned dm_get_md_type(struct mapped_device *md);
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int dm_setup_md_queue(struct mapped_device *md);
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/*
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* To check the return value from dm_table_find_target().
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*/
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#define dm_target_is_valid(t) ((t)->table)
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/*
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* To check whether the target type is request-based or not (bio-based).
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*/
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#define dm_target_request_based(t) ((t)->type->map_rq != NULL)
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/*-----------------------------------------------------------------
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* A registry of target types.
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*---------------------------------------------------------------*/
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int dm_target_init(void);
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void dm_target_exit(void);
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struct target_type *dm_get_target_type(const char *name);
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void dm_put_target_type(struct target_type *tt);
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int dm_target_iterate(void (*iter_func)(struct target_type *tt,
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void *param), void *param);
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int dm_split_args(int *argc, char ***argvp, char *input);
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/*
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* Is this mapped_device being deleted?
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*/
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int dm_deleting_md(struct mapped_device *md);
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/*
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* Is this mapped_device suspended?
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*/
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int dm_suspended_md(struct mapped_device *md);
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/*
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* The device-mapper can be driven through one of two interfaces;
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* ioctl or filesystem, depending which patch you have applied.
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*/
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int dm_interface_init(void);
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void dm_interface_exit(void);
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/*
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* sysfs interface
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*/
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int dm_sysfs_init(struct mapped_device *md);
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void dm_sysfs_exit(struct mapped_device *md);
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struct kobject *dm_kobject(struct mapped_device *md);
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struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
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/*
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* Targets for linear and striped mappings
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*/
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int dm_linear_init(void);
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void dm_linear_exit(void);
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int dm_stripe_init(void);
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void dm_stripe_exit(void);
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/*
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* mapped_device operations
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*/
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void dm_destroy(struct mapped_device *md);
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void dm_destroy_immediate(struct mapped_device *md);
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int dm_open_count(struct mapped_device *md);
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int dm_lock_for_deletion(struct mapped_device *md);
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int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
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unsigned cookie);
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int dm_io_init(void);
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void dm_io_exit(void);
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int dm_kcopyd_init(void);
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void dm_kcopyd_exit(void);
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/*
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* Mempool operations
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*/
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struct dm_md_mempools *dm_alloc_md_mempools(unsigned type);
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void dm_free_md_mempools(struct dm_md_mempools *pools);
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#endif
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