// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2003 Sistina Software Limited. * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ #include <linux/dm-dirty-log.h> #include <linux/dm-region-hash.h> #include <linux/ctype.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include "dm.h" #define DM_MSG_PREFIX … /* *------------------------------------------------------------------ * Region hash * * The mirror splits itself up into discrete regions. Each * region can be in one of three states: clean, dirty, * nosync. There is no need to put clean regions in the hash. * * In addition to being present in the hash table a region _may_ * be present on one of three lists. * * clean_regions: Regions on this list have no io pending to * them, they are in sync, we are no longer interested in them, * they are dull. dm_rh_update_states() will remove them from the * hash table. * * quiesced_regions: These regions have been spun down, ready * for recovery. rh_recovery_start() will remove regions from * this list and hand them to kmirrord, which will schedule the * recovery io with kcopyd. * * recovered_regions: Regions that kcopyd has successfully * recovered. dm_rh_update_states() will now schedule any delayed * io, up the recovery_count, and remove the region from the * hash. * * There are 2 locks: * A rw spin lock 'hash_lock' protects just the hash table, * this is never held in write mode from interrupt context, * which I believe means that we only have to disable irqs when * doing a write lock. * * An ordinary spin lock 'region_lock' that protects the three * lists in the region_hash, with the 'state', 'list' and * 'delayed_bios' fields of the regions. This is used from irq * context, so all other uses will have to suspend local irqs. *------------------------------------------------------------------ */ struct dm_region_hash { … }; struct dm_region { … }; /* * Conversion fns */ static region_t dm_rh_sector_to_region(struct dm_region_hash *rh, sector_t sector) { … } sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region) { … } EXPORT_SYMBOL_GPL(…); region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio) { … } EXPORT_SYMBOL_GPL(…); void *dm_rh_region_context(struct dm_region *reg) { … } EXPORT_SYMBOL_GPL(…); region_t dm_rh_get_region_key(struct dm_region *reg) { … } EXPORT_SYMBOL_GPL(…); sector_t dm_rh_get_region_size(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); /* * FIXME: shall we pass in a structure instead of all these args to * dm_region_hash_create()???? */ #define RH_HASH_MULT … #define RH_HASH_SHIFT … #define MIN_REGIONS … struct dm_region_hash *dm_region_hash_create( void *context, void (*dispatch_bios)(void *context, struct bio_list *bios), void (*wakeup_workers)(void *context), void (*wakeup_all_recovery_waiters)(void *context), sector_t target_begin, unsigned int max_recovery, struct dm_dirty_log *log, uint32_t region_size, region_t nr_regions) { … } EXPORT_SYMBOL_GPL(…); void dm_region_hash_destroy(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); static unsigned int rh_hash(struct dm_region_hash *rh, region_t region) { … } static struct dm_region *__rh_lookup(struct dm_region_hash *rh, region_t region) { … } static void __rh_insert(struct dm_region_hash *rh, struct dm_region *reg) { … } static struct dm_region *__rh_alloc(struct dm_region_hash *rh, region_t region) { … } static struct dm_region *__rh_find(struct dm_region_hash *rh, region_t region) { … } int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block) { … } EXPORT_SYMBOL_GPL(…); static void complete_resync_work(struct dm_region *reg, int success) { … } /* dm_rh_mark_nosync * @ms * @bio * * The bio was written on some mirror(s) but failed on other mirror(s). * We can successfully endio the bio but should avoid the region being * marked clean by setting the state DM_RH_NOSYNC. * * This function is _not_ safe in interrupt context! */ void dm_rh_mark_nosync(struct dm_region_hash *rh, struct bio *bio) { … } EXPORT_SYMBOL_GPL(…); void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled) { … } EXPORT_SYMBOL_GPL(…); static void rh_inc(struct dm_region_hash *rh, region_t region) { … } void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios) { … } EXPORT_SYMBOL_GPL(…); void dm_rh_dec(struct dm_region_hash *rh, region_t region) { … } EXPORT_SYMBOL_GPL(…); /* * Starts quiescing a region in preparation for recovery. */ static int __rh_recovery_prepare(struct dm_region_hash *rh) { … } void dm_rh_recovery_prepare(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); /* * Returns any quiesced regions. */ struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); void dm_rh_recovery_end(struct dm_region *reg, int success) { … } EXPORT_SYMBOL_GPL(…); /* Return recovery in flight count. */ int dm_rh_recovery_in_flight(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); int dm_rh_flush(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio) { … } EXPORT_SYMBOL_GPL(…); void dm_rh_stop_recovery(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); void dm_rh_start_recovery(struct dm_region_hash *rh) { … } EXPORT_SYMBOL_GPL(…); MODULE_DESCRIPTION(…) …; MODULE_AUTHOR(…) …; MODULE_LICENSE(…) …;
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