b73c67c2cb
When copyying blocks to host-managed zoned block devices, writes must be sequential. However, dm_kcopyd_copy() does not guarantee this as writes are issued in the completion order of reads, and reads may complete out of order despite being issued sequentially. Fix this by introducing the DM_KCOPYD_WRITE_SEQ feature flag. This can be specified when calling dm_kcopyd_copy() and should be set automatically if one of the destinations is a host-managed zoned block device. For a split job, the master job maintains the write position at which writes must be issued. This is checked with the pop() function which is modified to not return any write I/O sub job that is not at the correct write position. When DM_KCOPYD_WRITE_SEQ is specified for a job, errors cannot be ignored and the flag DM_KCOPYD_IGNORE_ERROR is ignored, even if specified by the user. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
89 lines
2.9 KiB
C
89 lines
2.9 KiB
C
/*
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* Copyright (C) 2001 - 2003 Sistina Software
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* Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
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*
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* kcopyd provides a simple interface for copying an area of one
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* block-device to one or more other block-devices, either synchronous
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* or with an asynchronous completion notification.
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*
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* This file is released under the GPL.
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*/
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#ifndef _LINUX_DM_KCOPYD_H
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#define _LINUX_DM_KCOPYD_H
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#ifdef __KERNEL__
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#include <linux/dm-io.h>
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/* FIXME: make this configurable */
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#define DM_KCOPYD_MAX_REGIONS 8
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#define DM_KCOPYD_IGNORE_ERROR 1
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#define DM_KCOPYD_WRITE_SEQ 2
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struct dm_kcopyd_throttle {
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unsigned throttle;
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unsigned num_io_jobs;
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unsigned io_period;
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unsigned total_period;
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unsigned last_jiffies;
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};
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/*
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* kcopyd clients that want to support throttling must pass an initialised
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* dm_kcopyd_throttle struct into dm_kcopyd_client_create().
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* Two or more clients may share the same instance of this struct between
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* them if they wish to be throttled as a group.
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*
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* This macro also creates a corresponding module parameter to configure
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* the amount of throttling.
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*/
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#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) \
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static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
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module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
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MODULE_PARM_DESC(name, description)
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/*
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* To use kcopyd you must first create a dm_kcopyd_client object.
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* throttle can be NULL if you don't want any throttling.
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*/
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struct dm_kcopyd_client;
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struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
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void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
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/*
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* Submit a copy job to kcopyd. This is built on top of the
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* previous three fns.
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*
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* read_err is a boolean,
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* write_err is a bitset, with 1 bit for each destination region
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*/
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typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
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void *context);
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int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
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unsigned num_dests, struct dm_io_region *dests,
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unsigned flags, dm_kcopyd_notify_fn fn, void *context);
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/*
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* Prepare a callback and submit it via the kcopyd thread.
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*
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* dm_kcopyd_prepare_callback allocates a callback structure and returns it.
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* It must not be called from interrupt context.
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* The returned value should be passed into dm_kcopyd_do_callback.
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*
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* dm_kcopyd_do_callback submits the callback.
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* It may be called from interrupt context.
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* The callback is issued from the kcopyd thread.
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*/
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void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
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dm_kcopyd_notify_fn fn, void *context);
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void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);
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int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
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unsigned num_dests, struct dm_io_region *dests,
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unsigned flags, dm_kcopyd_notify_fn fn, void *context);
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#endif /* __KERNEL__ */
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#endif /* _LINUX_DM_KCOPYD_H */
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