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![Heinz Mauelshagen](/assets/img/avatar_default.png)
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2228 lines
54 KiB
C
2228 lines
54 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2019 Arrikto, Inc. All Rights Reserved.
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*/
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#include <linux/mm.h>
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#include <linux/bio.h>
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#include <linux/err.h>
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#include <linux/hash.h>
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#include <linux/list.h>
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#include <linux/log2.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/wait.h>
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#include <linux/dm-io.h>
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#include <linux/mutex.h>
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#include <linux/atomic.h>
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#include <linux/bitops.h>
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#include <linux/blkdev.h>
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#include <linux/kdev_t.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/jiffies.h>
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#include <linux/mempool.h>
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#include <linux/spinlock.h>
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#include <linux/blk_types.h>
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#include <linux/dm-kcopyd.h>
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#include <linux/workqueue.h>
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#include <linux/backing-dev.h>
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#include <linux/device-mapper.h>
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#include "dm.h"
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#include "dm-clone-metadata.h"
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#define DM_MSG_PREFIX "clone"
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/*
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* Minimum and maximum allowed region sizes
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*/
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#define MIN_REGION_SIZE (1 << 3) /* 4KB */
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#define MAX_REGION_SIZE (1 << 21) /* 1GB */
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#define MIN_HYDRATIONS 256 /* Size of hydration mempool */
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#define DEFAULT_HYDRATION_THRESHOLD 1 /* 1 region */
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#define DEFAULT_HYDRATION_BATCH_SIZE 1 /* Hydrate in batches of 1 region */
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#define COMMIT_PERIOD HZ /* 1 sec */
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/*
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* Hydration hash table size: 1 << HASH_TABLE_BITS
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*/
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#define HASH_TABLE_BITS 15
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DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(clone_hydration_throttle,
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"A percentage of time allocated for hydrating regions");
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/* Slab cache for struct dm_clone_region_hydration */
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static struct kmem_cache *_hydration_cache;
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/* dm-clone metadata modes */
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enum clone_metadata_mode {
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CM_WRITE, /* metadata may be changed */
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CM_READ_ONLY, /* metadata may not be changed */
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CM_FAIL, /* all metadata I/O fails */
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};
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struct hash_table_bucket;
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struct clone {
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struct dm_target *ti;
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struct dm_dev *metadata_dev;
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struct dm_dev *dest_dev;
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struct dm_dev *source_dev;
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unsigned long nr_regions;
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sector_t region_size;
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unsigned int region_shift;
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/*
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* A metadata commit and the actions taken in case it fails should run
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* as a single atomic step.
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*/
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struct mutex commit_lock;
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struct dm_clone_metadata *cmd;
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/* Region hydration hash table */
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struct hash_table_bucket *ht;
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atomic_t ios_in_flight;
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wait_queue_head_t hydration_stopped;
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mempool_t hydration_pool;
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unsigned long last_commit_jiffies;
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/*
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* We defer incoming WRITE bios for regions that are not hydrated,
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* until after these regions have been hydrated.
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*
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* Also, we defer REQ_FUA and REQ_PREFLUSH bios, until after the
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* metadata have been committed.
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*/
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spinlock_t lock;
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struct bio_list deferred_bios;
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struct bio_list deferred_discard_bios;
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struct bio_list deferred_flush_bios;
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struct bio_list deferred_flush_completions;
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/* Maximum number of regions being copied during background hydration. */
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unsigned int hydration_threshold;
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/* Number of regions to batch together during background hydration. */
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unsigned int hydration_batch_size;
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/* Which region to hydrate next */
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unsigned long hydration_offset;
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atomic_t hydrations_in_flight;
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/*
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* Save a copy of the table line rather than reconstructing it for the
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* status.
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*/
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unsigned int nr_ctr_args;
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const char **ctr_args;
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struct workqueue_struct *wq;
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struct work_struct worker;
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struct delayed_work waker;
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struct dm_kcopyd_client *kcopyd_client;
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enum clone_metadata_mode mode;
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unsigned long flags;
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};
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/*
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* dm-clone flags
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*/
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#define DM_CLONE_DISCARD_PASSDOWN 0
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#define DM_CLONE_HYDRATION_ENABLED 1
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#define DM_CLONE_HYDRATION_SUSPENDED 2
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/*---------------------------------------------------------------------------*/
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/*
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* Metadata failure handling.
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*/
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static enum clone_metadata_mode get_clone_mode(struct clone *clone)
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{
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return READ_ONCE(clone->mode);
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}
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static const char *clone_device_name(struct clone *clone)
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{
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return dm_table_device_name(clone->ti->table);
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}
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static void __set_clone_mode(struct clone *clone, enum clone_metadata_mode new_mode)
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{
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static const char * const descs[] = {
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"read-write",
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"read-only",
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"fail"
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};
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enum clone_metadata_mode old_mode = get_clone_mode(clone);
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/* Never move out of fail mode */
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if (old_mode == CM_FAIL)
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new_mode = CM_FAIL;
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switch (new_mode) {
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case CM_FAIL:
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case CM_READ_ONLY:
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dm_clone_metadata_set_read_only(clone->cmd);
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break;
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case CM_WRITE:
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dm_clone_metadata_set_read_write(clone->cmd);
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break;
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}
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WRITE_ONCE(clone->mode, new_mode);
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if (new_mode != old_mode) {
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dm_table_event(clone->ti->table);
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DMINFO("%s: Switching to %s mode", clone_device_name(clone),
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descs[(int)new_mode]);
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}
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}
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static void __abort_transaction(struct clone *clone)
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{
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const char *dev_name = clone_device_name(clone);
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if (get_clone_mode(clone) >= CM_READ_ONLY)
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return;
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DMERR("%s: Aborting current metadata transaction", dev_name);
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if (dm_clone_metadata_abort(clone->cmd)) {
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DMERR("%s: Failed to abort metadata transaction", dev_name);
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__set_clone_mode(clone, CM_FAIL);
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}
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}
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static void __reload_in_core_bitset(struct clone *clone)
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{
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const char *dev_name = clone_device_name(clone);
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if (get_clone_mode(clone) == CM_FAIL)
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return;
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/* Reload the on-disk bitset */
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DMINFO("%s: Reloading on-disk bitmap", dev_name);
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if (dm_clone_reload_in_core_bitset(clone->cmd)) {
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DMERR("%s: Failed to reload on-disk bitmap", dev_name);
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__set_clone_mode(clone, CM_FAIL);
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}
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}
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static void __metadata_operation_failed(struct clone *clone, const char *op, int r)
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{
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DMERR("%s: Metadata operation `%s' failed: error = %d",
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clone_device_name(clone), op, r);
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__abort_transaction(clone);
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__set_clone_mode(clone, CM_READ_ONLY);
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/*
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* dm_clone_reload_in_core_bitset() may run concurrently with either
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* dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), but
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* it's safe as we have already set the metadata to read-only mode.
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*/
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__reload_in_core_bitset(clone);
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}
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/*---------------------------------------------------------------------------*/
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/* Wake up anyone waiting for region hydrations to stop */
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static inline void wakeup_hydration_waiters(struct clone *clone)
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{
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wake_up_all(&clone->hydration_stopped);
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}
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static inline void wake_worker(struct clone *clone)
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{
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queue_work(clone->wq, &clone->worker);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* bio helper functions.
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*/
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static inline void remap_to_source(struct clone *clone, struct bio *bio)
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{
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bio_set_dev(bio, clone->source_dev->bdev);
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}
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static inline void remap_to_dest(struct clone *clone, struct bio *bio)
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{
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bio_set_dev(bio, clone->dest_dev->bdev);
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}
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static bool bio_triggers_commit(struct clone *clone, struct bio *bio)
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{
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return op_is_flush(bio->bi_opf) &&
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dm_clone_changed_this_transaction(clone->cmd);
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}
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/* Get the address of the region in sectors */
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static inline sector_t region_to_sector(struct clone *clone, unsigned long region_nr)
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{
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return ((sector_t)region_nr << clone->region_shift);
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}
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/* Get the region number of the bio */
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static inline unsigned long bio_to_region(struct clone *clone, struct bio *bio)
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{
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return (bio->bi_iter.bi_sector >> clone->region_shift);
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}
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/* Get the region range covered by the bio */
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static void bio_region_range(struct clone *clone, struct bio *bio,
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unsigned long *rs, unsigned long *nr_regions)
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{
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unsigned long end;
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*rs = dm_sector_div_up(bio->bi_iter.bi_sector, clone->region_size);
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end = bio_end_sector(bio) >> clone->region_shift;
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if (*rs >= end)
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*nr_regions = 0;
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else
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*nr_regions = end - *rs;
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}
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/* Check whether a bio overwrites a region */
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static inline bool is_overwrite_bio(struct clone *clone, struct bio *bio)
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{
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return (bio_data_dir(bio) == WRITE && bio_sectors(bio) == clone->region_size);
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}
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static void fail_bios(struct bio_list *bios, blk_status_t status)
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{
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struct bio *bio;
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while ((bio = bio_list_pop(bios))) {
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bio->bi_status = status;
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bio_endio(bio);
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}
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}
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static void submit_bios(struct bio_list *bios)
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{
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struct bio *bio;
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struct blk_plug plug;
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blk_start_plug(&plug);
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while ((bio = bio_list_pop(bios)))
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submit_bio_noacct(bio);
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blk_finish_plug(&plug);
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}
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/*
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* Submit bio to the underlying device.
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*
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* If the bio triggers a commit, delay it, until after the metadata have been
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* committed.
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*
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* NOTE: The bio remapping must be performed by the caller.
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*/
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static void issue_bio(struct clone *clone, struct bio *bio)
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{
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if (!bio_triggers_commit(clone, bio)) {
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submit_bio_noacct(bio);
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return;
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}
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/*
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* If the metadata mode is RO or FAIL we won't be able to commit the
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* metadata, so we complete the bio with an error.
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*/
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if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY)) {
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bio_io_error(bio);
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return;
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}
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/*
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* Batch together any bios that trigger commits and then issue a single
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* commit for them in process_deferred_flush_bios().
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*/
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spin_lock_irq(&clone->lock);
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bio_list_add(&clone->deferred_flush_bios, bio);
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spin_unlock_irq(&clone->lock);
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wake_worker(clone);
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}
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/*
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* Remap bio to the destination device and submit it.
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*
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* If the bio triggers a commit, delay it, until after the metadata have been
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* committed.
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*/
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static void remap_and_issue(struct clone *clone, struct bio *bio)
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{
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remap_to_dest(clone, bio);
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issue_bio(clone, bio);
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}
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/*
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* Issue bios that have been deferred until after their region has finished
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* hydrating.
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*
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* We delegate the bio submission to the worker thread, so this is safe to call
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* from interrupt context.
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*/
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static void issue_deferred_bios(struct clone *clone, struct bio_list *bios)
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{
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struct bio *bio;
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unsigned long flags;
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struct bio_list flush_bios = BIO_EMPTY_LIST;
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struct bio_list normal_bios = BIO_EMPTY_LIST;
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if (bio_list_empty(bios))
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return;
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while ((bio = bio_list_pop(bios))) {
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if (bio_triggers_commit(clone, bio))
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bio_list_add(&flush_bios, bio);
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else
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bio_list_add(&normal_bios, bio);
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}
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spin_lock_irqsave(&clone->lock, flags);
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bio_list_merge(&clone->deferred_bios, &normal_bios);
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bio_list_merge(&clone->deferred_flush_bios, &flush_bios);
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spin_unlock_irqrestore(&clone->lock, flags);
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wake_worker(clone);
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}
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static void complete_overwrite_bio(struct clone *clone, struct bio *bio)
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{
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unsigned long flags;
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/*
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* If the bio has the REQ_FUA flag set we must commit the metadata
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* before signaling its completion.
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*
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* complete_overwrite_bio() is only called by hydration_complete(),
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* after having successfully updated the metadata. This means we don't
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* need to call dm_clone_changed_this_transaction() to check if the
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* metadata has changed and thus we can avoid taking the metadata spin
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* lock.
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*/
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if (!(bio->bi_opf & REQ_FUA)) {
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bio_endio(bio);
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return;
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}
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/*
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* If the metadata mode is RO or FAIL we won't be able to commit the
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* metadata, so we complete the bio with an error.
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*/
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if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY)) {
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bio_io_error(bio);
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return;
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}
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/*
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* Batch together any bios that trigger commits and then issue a single
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* commit for them in process_deferred_flush_bios().
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*/
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spin_lock_irqsave(&clone->lock, flags);
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bio_list_add(&clone->deferred_flush_completions, bio);
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spin_unlock_irqrestore(&clone->lock, flags);
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wake_worker(clone);
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}
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static void trim_bio(struct bio *bio, sector_t sector, unsigned int len)
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{
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bio->bi_iter.bi_sector = sector;
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bio->bi_iter.bi_size = to_bytes(len);
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}
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static void complete_discard_bio(struct clone *clone, struct bio *bio, bool success)
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{
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unsigned long rs, nr_regions;
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/*
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* If the destination device supports discards, remap and trim the
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* discard bio and pass it down. Otherwise complete the bio
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* immediately.
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*/
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if (test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags) && success) {
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remap_to_dest(clone, bio);
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bio_region_range(clone, bio, &rs, &nr_regions);
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trim_bio(bio, region_to_sector(clone, rs),
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nr_regions << clone->region_shift);
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submit_bio_noacct(bio);
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} else
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bio_endio(bio);
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}
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static void process_discard_bio(struct clone *clone, struct bio *bio)
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{
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unsigned long rs, nr_regions;
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bio_region_range(clone, bio, &rs, &nr_regions);
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if (!nr_regions) {
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bio_endio(bio);
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return;
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}
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if (WARN_ON(rs >= clone->nr_regions || (rs + nr_regions) < rs ||
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(rs + nr_regions) > clone->nr_regions)) {
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DMERR("%s: Invalid range (%lu + %lu, total regions %lu) for discard (%llu + %u)",
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clone_device_name(clone), rs, nr_regions,
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clone->nr_regions,
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(unsigned long long)bio->bi_iter.bi_sector,
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bio_sectors(bio));
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bio_endio(bio);
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return;
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}
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/*
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* The covered regions are already hydrated so we just need to pass
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* down the discard.
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*/
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if (dm_clone_is_range_hydrated(clone->cmd, rs, nr_regions)) {
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complete_discard_bio(clone, bio, true);
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return;
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}
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/*
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* If the metadata mode is RO or FAIL we won't be able to update the
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* metadata for the regions covered by the discard so we just ignore
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* it.
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*/
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if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY)) {
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bio_endio(bio);
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return;
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}
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/*
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* Defer discard processing.
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*/
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spin_lock_irq(&clone->lock);
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bio_list_add(&clone->deferred_discard_bios, bio);
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spin_unlock_irq(&clone->lock);
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wake_worker(clone);
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}
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/*---------------------------------------------------------------------------*/
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/*
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* dm-clone region hydrations.
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*/
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struct dm_clone_region_hydration {
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struct clone *clone;
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unsigned long region_nr;
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struct bio *overwrite_bio;
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bio_end_io_t *overwrite_bio_end_io;
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struct bio_list deferred_bios;
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blk_status_t status;
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/* Used by hydration batching */
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struct list_head list;
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/* Used by hydration hash table */
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struct hlist_node h;
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};
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/*
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* Hydration hash table implementation.
|
|
*
|
|
* Ideally we would like to use list_bl, which uses bit spin locks and employs
|
|
* the least significant bit of the list head to lock the corresponding bucket,
|
|
* reducing the memory overhead for the locks. But, currently, list_bl and bit
|
|
* spin locks don't support IRQ safe versions. Since we have to take the lock
|
|
* in both process and interrupt context, we must fall back to using regular
|
|
* spin locks; one per hash table bucket.
|
|
*/
|
|
struct hash_table_bucket {
|
|
struct hlist_head head;
|
|
|
|
/* Spinlock protecting the bucket */
|
|
spinlock_t lock;
|
|
};
|
|
|
|
#define bucket_lock_irqsave(bucket, flags) \
|
|
spin_lock_irqsave(&(bucket)->lock, flags)
|
|
|
|
#define bucket_unlock_irqrestore(bucket, flags) \
|
|
spin_unlock_irqrestore(&(bucket)->lock, flags)
|
|
|
|
#define bucket_lock_irq(bucket) \
|
|
spin_lock_irq(&(bucket)->lock)
|
|
|
|
#define bucket_unlock_irq(bucket) \
|
|
spin_unlock_irq(&(bucket)->lock)
|
|
|
|
static int hash_table_init(struct clone *clone)
|
|
{
|
|
unsigned int i, sz;
|
|
struct hash_table_bucket *bucket;
|
|
|
|
sz = 1 << HASH_TABLE_BITS;
|
|
|
|
clone->ht = kvmalloc_array(sz, sizeof(struct hash_table_bucket), GFP_KERNEL);
|
|
if (!clone->ht)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; i < sz; i++) {
|
|
bucket = clone->ht + i;
|
|
|
|
INIT_HLIST_HEAD(&bucket->head);
|
|
spin_lock_init(&bucket->lock);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void hash_table_exit(struct clone *clone)
|
|
{
|
|
kvfree(clone->ht);
|
|
}
|
|
|
|
static struct hash_table_bucket *get_hash_table_bucket(struct clone *clone,
|
|
unsigned long region_nr)
|
|
{
|
|
return &clone->ht[hash_long(region_nr, HASH_TABLE_BITS)];
|
|
}
|
|
|
|
/*
|
|
* Search hash table for a hydration with hd->region_nr == region_nr
|
|
*
|
|
* NOTE: Must be called with the bucket lock held
|
|
*/
|
|
static struct dm_clone_region_hydration *__hash_find(struct hash_table_bucket *bucket,
|
|
unsigned long region_nr)
|
|
{
|
|
struct dm_clone_region_hydration *hd;
|
|
|
|
hlist_for_each_entry(hd, &bucket->head, h) {
|
|
if (hd->region_nr == region_nr)
|
|
return hd;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Insert a hydration into the hash table.
|
|
*
|
|
* NOTE: Must be called with the bucket lock held.
|
|
*/
|
|
static inline void __insert_region_hydration(struct hash_table_bucket *bucket,
|
|
struct dm_clone_region_hydration *hd)
|
|
{
|
|
hlist_add_head(&hd->h, &bucket->head);
|
|
}
|
|
|
|
/*
|
|
* This function inserts a hydration into the hash table, unless someone else
|
|
* managed to insert a hydration for the same region first. In the latter case
|
|
* it returns the existing hydration descriptor for this region.
|
|
*
|
|
* NOTE: Must be called with the hydration hash table lock held.
|
|
*/
|
|
static struct dm_clone_region_hydration *
|
|
__find_or_insert_region_hydration(struct hash_table_bucket *bucket,
|
|
struct dm_clone_region_hydration *hd)
|
|
{
|
|
struct dm_clone_region_hydration *hd2;
|
|
|
|
hd2 = __hash_find(bucket, hd->region_nr);
|
|
if (hd2)
|
|
return hd2;
|
|
|
|
__insert_region_hydration(bucket, hd);
|
|
|
|
return hd;
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/* Allocate a hydration */
|
|
static struct dm_clone_region_hydration *alloc_hydration(struct clone *clone)
|
|
{
|
|
struct dm_clone_region_hydration *hd;
|
|
|
|
/*
|
|
* Allocate a hydration from the hydration mempool.
|
|
* This might block but it can't fail.
|
|
*/
|
|
hd = mempool_alloc(&clone->hydration_pool, GFP_NOIO);
|
|
hd->clone = clone;
|
|
|
|
return hd;
|
|
}
|
|
|
|
static inline void free_hydration(struct dm_clone_region_hydration *hd)
|
|
{
|
|
mempool_free(hd, &hd->clone->hydration_pool);
|
|
}
|
|
|
|
/* Initialize a hydration */
|
|
static void hydration_init(struct dm_clone_region_hydration *hd, unsigned long region_nr)
|
|
{
|
|
hd->region_nr = region_nr;
|
|
hd->overwrite_bio = NULL;
|
|
bio_list_init(&hd->deferred_bios);
|
|
hd->status = 0;
|
|
|
|
INIT_LIST_HEAD(&hd->list);
|
|
INIT_HLIST_NODE(&hd->h);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Update dm-clone's metadata after a region has finished hydrating and remove
|
|
* hydration from the hash table.
|
|
*/
|
|
static int hydration_update_metadata(struct dm_clone_region_hydration *hd)
|
|
{
|
|
int r = 0;
|
|
unsigned long flags;
|
|
struct hash_table_bucket *bucket;
|
|
struct clone *clone = hd->clone;
|
|
|
|
if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY))
|
|
r = -EPERM;
|
|
|
|
/* Update the metadata */
|
|
if (likely(!r) && hd->status == BLK_STS_OK)
|
|
r = dm_clone_set_region_hydrated(clone->cmd, hd->region_nr);
|
|
|
|
bucket = get_hash_table_bucket(clone, hd->region_nr);
|
|
|
|
/* Remove hydration from hash table */
|
|
bucket_lock_irqsave(bucket, flags);
|
|
hlist_del(&hd->h);
|
|
bucket_unlock_irqrestore(bucket, flags);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Complete a region's hydration:
|
|
*
|
|
* 1. Update dm-clone's metadata.
|
|
* 2. Remove hydration from hash table.
|
|
* 3. Complete overwrite bio.
|
|
* 4. Issue deferred bios.
|
|
* 5. If this was the last hydration, wake up anyone waiting for
|
|
* hydrations to finish.
|
|
*/
|
|
static void hydration_complete(struct dm_clone_region_hydration *hd)
|
|
{
|
|
int r;
|
|
blk_status_t status;
|
|
struct clone *clone = hd->clone;
|
|
|
|
r = hydration_update_metadata(hd);
|
|
|
|
if (hd->status == BLK_STS_OK && likely(!r)) {
|
|
if (hd->overwrite_bio)
|
|
complete_overwrite_bio(clone, hd->overwrite_bio);
|
|
|
|
issue_deferred_bios(clone, &hd->deferred_bios);
|
|
} else {
|
|
status = r ? BLK_STS_IOERR : hd->status;
|
|
|
|
if (hd->overwrite_bio)
|
|
bio_list_add(&hd->deferred_bios, hd->overwrite_bio);
|
|
|
|
fail_bios(&hd->deferred_bios, status);
|
|
}
|
|
|
|
free_hydration(hd);
|
|
|
|
if (atomic_dec_and_test(&clone->hydrations_in_flight))
|
|
wakeup_hydration_waiters(clone);
|
|
}
|
|
|
|
static void hydration_kcopyd_callback(int read_err, unsigned long write_err, void *context)
|
|
{
|
|
blk_status_t status;
|
|
|
|
struct dm_clone_region_hydration *tmp, *hd = context;
|
|
struct clone *clone = hd->clone;
|
|
|
|
LIST_HEAD(batched_hydrations);
|
|
|
|
if (read_err || write_err) {
|
|
DMERR_LIMIT("%s: hydration failed", clone_device_name(clone));
|
|
status = BLK_STS_IOERR;
|
|
} else {
|
|
status = BLK_STS_OK;
|
|
}
|
|
list_splice_tail(&hd->list, &batched_hydrations);
|
|
|
|
hd->status = status;
|
|
hydration_complete(hd);
|
|
|
|
/* Complete batched hydrations */
|
|
list_for_each_entry_safe(hd, tmp, &batched_hydrations, list) {
|
|
hd->status = status;
|
|
hydration_complete(hd);
|
|
}
|
|
|
|
/* Continue background hydration, if there is no I/O in-flight */
|
|
if (test_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags) &&
|
|
!atomic_read(&clone->ios_in_flight))
|
|
wake_worker(clone);
|
|
}
|
|
|
|
static void hydration_copy(struct dm_clone_region_hydration *hd, unsigned int nr_regions)
|
|
{
|
|
unsigned long region_start, region_end;
|
|
sector_t tail_size, region_size, total_size;
|
|
struct dm_io_region from, to;
|
|
struct clone *clone = hd->clone;
|
|
|
|
if (WARN_ON(!nr_regions))
|
|
return;
|
|
|
|
region_size = clone->region_size;
|
|
region_start = hd->region_nr;
|
|
region_end = region_start + nr_regions - 1;
|
|
|
|
total_size = region_to_sector(clone, nr_regions - 1);
|
|
|
|
if (region_end == clone->nr_regions - 1) {
|
|
/*
|
|
* The last region of the target might be smaller than
|
|
* region_size.
|
|
*/
|
|
tail_size = clone->ti->len & (region_size - 1);
|
|
if (!tail_size)
|
|
tail_size = region_size;
|
|
} else {
|
|
tail_size = region_size;
|
|
}
|
|
|
|
total_size += tail_size;
|
|
|
|
from.bdev = clone->source_dev->bdev;
|
|
from.sector = region_to_sector(clone, region_start);
|
|
from.count = total_size;
|
|
|
|
to.bdev = clone->dest_dev->bdev;
|
|
to.sector = from.sector;
|
|
to.count = from.count;
|
|
|
|
/* Issue copy */
|
|
atomic_add(nr_regions, &clone->hydrations_in_flight);
|
|
dm_kcopyd_copy(clone->kcopyd_client, &from, 1, &to, 0,
|
|
hydration_kcopyd_callback, hd);
|
|
}
|
|
|
|
static void overwrite_endio(struct bio *bio)
|
|
{
|
|
struct dm_clone_region_hydration *hd = bio->bi_private;
|
|
|
|
bio->bi_end_io = hd->overwrite_bio_end_io;
|
|
hd->status = bio->bi_status;
|
|
|
|
hydration_complete(hd);
|
|
}
|
|
|
|
static void hydration_overwrite(struct dm_clone_region_hydration *hd, struct bio *bio)
|
|
{
|
|
/*
|
|
* We don't need to save and restore bio->bi_private because device
|
|
* mapper core generates a new bio for us to use, with clean
|
|
* bi_private.
|
|
*/
|
|
hd->overwrite_bio = bio;
|
|
hd->overwrite_bio_end_io = bio->bi_end_io;
|
|
|
|
bio->bi_end_io = overwrite_endio;
|
|
bio->bi_private = hd;
|
|
|
|
atomic_inc(&hd->clone->hydrations_in_flight);
|
|
submit_bio_noacct(bio);
|
|
}
|
|
|
|
/*
|
|
* Hydrate bio's region.
|
|
*
|
|
* This function starts the hydration of the bio's region and puts the bio in
|
|
* the list of deferred bios for this region. In case, by the time this
|
|
* function is called, the region has finished hydrating it's submitted to the
|
|
* destination device.
|
|
*
|
|
* NOTE: The bio remapping must be performed by the caller.
|
|
*/
|
|
static void hydrate_bio_region(struct clone *clone, struct bio *bio)
|
|
{
|
|
unsigned long region_nr;
|
|
struct hash_table_bucket *bucket;
|
|
struct dm_clone_region_hydration *hd, *hd2;
|
|
|
|
region_nr = bio_to_region(clone, bio);
|
|
bucket = get_hash_table_bucket(clone, region_nr);
|
|
|
|
bucket_lock_irq(bucket);
|
|
|
|
hd = __hash_find(bucket, region_nr);
|
|
if (hd) {
|
|
/* Someone else is hydrating the region */
|
|
bio_list_add(&hd->deferred_bios, bio);
|
|
bucket_unlock_irq(bucket);
|
|
return;
|
|
}
|
|
|
|
if (dm_clone_is_region_hydrated(clone->cmd, region_nr)) {
|
|
/* The region has been hydrated */
|
|
bucket_unlock_irq(bucket);
|
|
issue_bio(clone, bio);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* We must allocate a hydration descriptor and start the hydration of
|
|
* the corresponding region.
|
|
*/
|
|
bucket_unlock_irq(bucket);
|
|
|
|
hd = alloc_hydration(clone);
|
|
hydration_init(hd, region_nr);
|
|
|
|
bucket_lock_irq(bucket);
|
|
|
|
/* Check if the region has been hydrated in the meantime. */
|
|
if (dm_clone_is_region_hydrated(clone->cmd, region_nr)) {
|
|
bucket_unlock_irq(bucket);
|
|
free_hydration(hd);
|
|
issue_bio(clone, bio);
|
|
return;
|
|
}
|
|
|
|
hd2 = __find_or_insert_region_hydration(bucket, hd);
|
|
if (hd2 != hd) {
|
|
/* Someone else started the region's hydration. */
|
|
bio_list_add(&hd2->deferred_bios, bio);
|
|
bucket_unlock_irq(bucket);
|
|
free_hydration(hd);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If the metadata mode is RO or FAIL then there is no point starting a
|
|
* hydration, since we will not be able to update the metadata when the
|
|
* hydration finishes.
|
|
*/
|
|
if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY)) {
|
|
hlist_del(&hd->h);
|
|
bucket_unlock_irq(bucket);
|
|
free_hydration(hd);
|
|
bio_io_error(bio);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Start region hydration.
|
|
*
|
|
* If a bio overwrites a region, i.e., its size is equal to the
|
|
* region's size, then we don't need to copy the region from the source
|
|
* to the destination device.
|
|
*/
|
|
if (is_overwrite_bio(clone, bio)) {
|
|
bucket_unlock_irq(bucket);
|
|
hydration_overwrite(hd, bio);
|
|
} else {
|
|
bio_list_add(&hd->deferred_bios, bio);
|
|
bucket_unlock_irq(bucket);
|
|
hydration_copy(hd, 1);
|
|
}
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Background hydrations.
|
|
*/
|
|
|
|
/*
|
|
* Batch region hydrations.
|
|
*
|
|
* To better utilize device bandwidth we batch together the hydration of
|
|
* adjacent regions. This allows us to use small region sizes, e.g., 4KB, which
|
|
* is good for small, random write performance (because of the overwriting of
|
|
* un-hydrated regions) and at the same time issue big copy requests to kcopyd
|
|
* to achieve high hydration bandwidth.
|
|
*/
|
|
struct batch_info {
|
|
struct dm_clone_region_hydration *head;
|
|
unsigned int nr_batched_regions;
|
|
};
|
|
|
|
static void __batch_hydration(struct batch_info *batch,
|
|
struct dm_clone_region_hydration *hd)
|
|
{
|
|
struct clone *clone = hd->clone;
|
|
unsigned int max_batch_size = READ_ONCE(clone->hydration_batch_size);
|
|
|
|
if (batch->head) {
|
|
/* Try to extend the current batch */
|
|
if (batch->nr_batched_regions < max_batch_size &&
|
|
(batch->head->region_nr + batch->nr_batched_regions) == hd->region_nr) {
|
|
list_add_tail(&hd->list, &batch->head->list);
|
|
batch->nr_batched_regions++;
|
|
hd = NULL;
|
|
}
|
|
|
|
/* Check if we should issue the current batch */
|
|
if (batch->nr_batched_regions >= max_batch_size || hd) {
|
|
hydration_copy(batch->head, batch->nr_batched_regions);
|
|
batch->head = NULL;
|
|
batch->nr_batched_regions = 0;
|
|
}
|
|
}
|
|
|
|
if (!hd)
|
|
return;
|
|
|
|
/* We treat max batch sizes of zero and one equivalently */
|
|
if (max_batch_size <= 1) {
|
|
hydration_copy(hd, 1);
|
|
return;
|
|
}
|
|
|
|
/* Start a new batch */
|
|
BUG_ON(!list_empty(&hd->list));
|
|
batch->head = hd;
|
|
batch->nr_batched_regions = 1;
|
|
}
|
|
|
|
static unsigned long __start_next_hydration(struct clone *clone,
|
|
unsigned long offset,
|
|
struct batch_info *batch)
|
|
{
|
|
struct hash_table_bucket *bucket;
|
|
struct dm_clone_region_hydration *hd;
|
|
unsigned long nr_regions = clone->nr_regions;
|
|
|
|
hd = alloc_hydration(clone);
|
|
|
|
/* Try to find a region to hydrate. */
|
|
do {
|
|
offset = dm_clone_find_next_unhydrated_region(clone->cmd, offset);
|
|
if (offset == nr_regions)
|
|
break;
|
|
|
|
bucket = get_hash_table_bucket(clone, offset);
|
|
bucket_lock_irq(bucket);
|
|
|
|
if (!dm_clone_is_region_hydrated(clone->cmd, offset) &&
|
|
!__hash_find(bucket, offset)) {
|
|
hydration_init(hd, offset);
|
|
__insert_region_hydration(bucket, hd);
|
|
bucket_unlock_irq(bucket);
|
|
|
|
/* Batch hydration */
|
|
__batch_hydration(batch, hd);
|
|
|
|
return (offset + 1);
|
|
}
|
|
|
|
bucket_unlock_irq(bucket);
|
|
|
|
} while (++offset < nr_regions);
|
|
|
|
if (hd)
|
|
free_hydration(hd);
|
|
|
|
return offset;
|
|
}
|
|
|
|
/*
|
|
* This function searches for regions that still reside in the source device
|
|
* and starts their hydration.
|
|
*/
|
|
static void do_hydration(struct clone *clone)
|
|
{
|
|
unsigned int current_volume;
|
|
unsigned long offset, nr_regions = clone->nr_regions;
|
|
|
|
struct batch_info batch = {
|
|
.head = NULL,
|
|
.nr_batched_regions = 0,
|
|
};
|
|
|
|
if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY))
|
|
return;
|
|
|
|
if (dm_clone_is_hydration_done(clone->cmd))
|
|
return;
|
|
|
|
/*
|
|
* Avoid race with device suspension.
|
|
*/
|
|
atomic_inc(&clone->hydrations_in_flight);
|
|
|
|
/*
|
|
* Make sure atomic_inc() is ordered before test_bit(), otherwise we
|
|
* might race with clone_postsuspend() and start a region hydration
|
|
* after the target has been suspended.
|
|
*
|
|
* This is paired with the smp_mb__after_atomic() in
|
|
* clone_postsuspend().
|
|
*/
|
|
smp_mb__after_atomic();
|
|
|
|
offset = clone->hydration_offset;
|
|
while (likely(!test_bit(DM_CLONE_HYDRATION_SUSPENDED, &clone->flags)) &&
|
|
!atomic_read(&clone->ios_in_flight) &&
|
|
test_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags) &&
|
|
offset < nr_regions) {
|
|
current_volume = atomic_read(&clone->hydrations_in_flight);
|
|
current_volume += batch.nr_batched_regions;
|
|
|
|
if (current_volume > READ_ONCE(clone->hydration_threshold))
|
|
break;
|
|
|
|
offset = __start_next_hydration(clone, offset, &batch);
|
|
}
|
|
|
|
if (batch.head)
|
|
hydration_copy(batch.head, batch.nr_batched_regions);
|
|
|
|
if (offset >= nr_regions)
|
|
offset = 0;
|
|
|
|
clone->hydration_offset = offset;
|
|
|
|
if (atomic_dec_and_test(&clone->hydrations_in_flight))
|
|
wakeup_hydration_waiters(clone);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
static bool need_commit_due_to_time(struct clone *clone)
|
|
{
|
|
return !time_in_range(jiffies, clone->last_commit_jiffies,
|
|
clone->last_commit_jiffies + COMMIT_PERIOD);
|
|
}
|
|
|
|
/*
|
|
* A non-zero return indicates read-only or fail mode.
|
|
*/
|
|
static int commit_metadata(struct clone *clone, bool *dest_dev_flushed)
|
|
{
|
|
int r = 0;
|
|
|
|
if (dest_dev_flushed)
|
|
*dest_dev_flushed = false;
|
|
|
|
mutex_lock(&clone->commit_lock);
|
|
|
|
if (!dm_clone_changed_this_transaction(clone->cmd))
|
|
goto out;
|
|
|
|
if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY)) {
|
|
r = -EPERM;
|
|
goto out;
|
|
}
|
|
|
|
r = dm_clone_metadata_pre_commit(clone->cmd);
|
|
if (unlikely(r)) {
|
|
__metadata_operation_failed(clone, "dm_clone_metadata_pre_commit", r);
|
|
goto out;
|
|
}
|
|
|
|
r = blkdev_issue_flush(clone->dest_dev->bdev);
|
|
if (unlikely(r)) {
|
|
__metadata_operation_failed(clone, "flush destination device", r);
|
|
goto out;
|
|
}
|
|
|
|
if (dest_dev_flushed)
|
|
*dest_dev_flushed = true;
|
|
|
|
r = dm_clone_metadata_commit(clone->cmd);
|
|
if (unlikely(r)) {
|
|
__metadata_operation_failed(clone, "dm_clone_metadata_commit", r);
|
|
goto out;
|
|
}
|
|
|
|
if (dm_clone_is_hydration_done(clone->cmd))
|
|
dm_table_event(clone->ti->table);
|
|
out:
|
|
mutex_unlock(&clone->commit_lock);
|
|
|
|
return r;
|
|
}
|
|
|
|
static void process_deferred_discards(struct clone *clone)
|
|
{
|
|
int r = -EPERM;
|
|
struct bio *bio;
|
|
struct blk_plug plug;
|
|
unsigned long rs, nr_regions;
|
|
struct bio_list discards = BIO_EMPTY_LIST;
|
|
|
|
spin_lock_irq(&clone->lock);
|
|
bio_list_merge(&discards, &clone->deferred_discard_bios);
|
|
bio_list_init(&clone->deferred_discard_bios);
|
|
spin_unlock_irq(&clone->lock);
|
|
|
|
if (bio_list_empty(&discards))
|
|
return;
|
|
|
|
if (unlikely(get_clone_mode(clone) >= CM_READ_ONLY))
|
|
goto out;
|
|
|
|
/* Update the metadata */
|
|
bio_list_for_each(bio, &discards) {
|
|
bio_region_range(clone, bio, &rs, &nr_regions);
|
|
/*
|
|
* A discard request might cover regions that have been already
|
|
* hydrated. There is no need to update the metadata for these
|
|
* regions.
|
|
*/
|
|
r = dm_clone_cond_set_range(clone->cmd, rs, nr_regions);
|
|
if (unlikely(r))
|
|
break;
|
|
}
|
|
out:
|
|
blk_start_plug(&plug);
|
|
while ((bio = bio_list_pop(&discards)))
|
|
complete_discard_bio(clone, bio, r == 0);
|
|
blk_finish_plug(&plug);
|
|
}
|
|
|
|
static void process_deferred_bios(struct clone *clone)
|
|
{
|
|
struct bio_list bios = BIO_EMPTY_LIST;
|
|
|
|
spin_lock_irq(&clone->lock);
|
|
bio_list_merge(&bios, &clone->deferred_bios);
|
|
bio_list_init(&clone->deferred_bios);
|
|
spin_unlock_irq(&clone->lock);
|
|
|
|
if (bio_list_empty(&bios))
|
|
return;
|
|
|
|
submit_bios(&bios);
|
|
}
|
|
|
|
static void process_deferred_flush_bios(struct clone *clone)
|
|
{
|
|
struct bio *bio;
|
|
bool dest_dev_flushed;
|
|
struct bio_list bios = BIO_EMPTY_LIST;
|
|
struct bio_list bio_completions = BIO_EMPTY_LIST;
|
|
|
|
/*
|
|
* If there are any deferred flush bios, we must commit the metadata
|
|
* before issuing them or signaling their completion.
|
|
*/
|
|
spin_lock_irq(&clone->lock);
|
|
bio_list_merge(&bios, &clone->deferred_flush_bios);
|
|
bio_list_init(&clone->deferred_flush_bios);
|
|
|
|
bio_list_merge(&bio_completions, &clone->deferred_flush_completions);
|
|
bio_list_init(&clone->deferred_flush_completions);
|
|
spin_unlock_irq(&clone->lock);
|
|
|
|
if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) &&
|
|
!(dm_clone_changed_this_transaction(clone->cmd) && need_commit_due_to_time(clone)))
|
|
return;
|
|
|
|
if (commit_metadata(clone, &dest_dev_flushed)) {
|
|
bio_list_merge(&bios, &bio_completions);
|
|
|
|
while ((bio = bio_list_pop(&bios)))
|
|
bio_io_error(bio);
|
|
|
|
return;
|
|
}
|
|
|
|
clone->last_commit_jiffies = jiffies;
|
|
|
|
while ((bio = bio_list_pop(&bio_completions)))
|
|
bio_endio(bio);
|
|
|
|
while ((bio = bio_list_pop(&bios))) {
|
|
if ((bio->bi_opf & REQ_PREFLUSH) && dest_dev_flushed) {
|
|
/* We just flushed the destination device as part of
|
|
* the metadata commit, so there is no reason to send
|
|
* another flush.
|
|
*/
|
|
bio_endio(bio);
|
|
} else {
|
|
submit_bio_noacct(bio);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void do_worker(struct work_struct *work)
|
|
{
|
|
struct clone *clone = container_of(work, typeof(*clone), worker);
|
|
|
|
process_deferred_bios(clone);
|
|
process_deferred_discards(clone);
|
|
|
|
/*
|
|
* process_deferred_flush_bios():
|
|
*
|
|
* - Commit metadata
|
|
*
|
|
* - Process deferred REQ_FUA completions
|
|
*
|
|
* - Process deferred REQ_PREFLUSH bios
|
|
*/
|
|
process_deferred_flush_bios(clone);
|
|
|
|
/* Background hydration */
|
|
do_hydration(clone);
|
|
}
|
|
|
|
/*
|
|
* Commit periodically so that not too much unwritten data builds up.
|
|
*
|
|
* Also, restart background hydration, if it has been stopped by in-flight I/O.
|
|
*/
|
|
static void do_waker(struct work_struct *work)
|
|
{
|
|
struct clone *clone = container_of(to_delayed_work(work), struct clone, waker);
|
|
|
|
wake_worker(clone);
|
|
queue_delayed_work(clone->wq, &clone->waker, COMMIT_PERIOD);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Target methods
|
|
*/
|
|
static int clone_map(struct dm_target *ti, struct bio *bio)
|
|
{
|
|
struct clone *clone = ti->private;
|
|
unsigned long region_nr;
|
|
|
|
atomic_inc(&clone->ios_in_flight);
|
|
|
|
if (unlikely(get_clone_mode(clone) == CM_FAIL))
|
|
return DM_MAPIO_KILL;
|
|
|
|
/*
|
|
* REQ_PREFLUSH bios carry no data:
|
|
*
|
|
* - Commit metadata, if changed
|
|
*
|
|
* - Pass down to destination device
|
|
*/
|
|
if (bio->bi_opf & REQ_PREFLUSH) {
|
|
remap_and_issue(clone, bio);
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
|
|
|
|
/*
|
|
* dm-clone interprets discards and performs a fast hydration of the
|
|
* discarded regions, i.e., we skip the copy from the source device and
|
|
* just mark the regions as hydrated.
|
|
*/
|
|
if (bio_op(bio) == REQ_OP_DISCARD) {
|
|
process_discard_bio(clone, bio);
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
/*
|
|
* If the bio's region is hydrated, redirect it to the destination
|
|
* device.
|
|
*
|
|
* If the region is not hydrated and the bio is a READ, redirect it to
|
|
* the source device.
|
|
*
|
|
* Else, defer WRITE bio until after its region has been hydrated and
|
|
* start the region's hydration immediately.
|
|
*/
|
|
region_nr = bio_to_region(clone, bio);
|
|
if (dm_clone_is_region_hydrated(clone->cmd, region_nr)) {
|
|
remap_and_issue(clone, bio);
|
|
return DM_MAPIO_SUBMITTED;
|
|
} else if (bio_data_dir(bio) == READ) {
|
|
remap_to_source(clone, bio);
|
|
return DM_MAPIO_REMAPPED;
|
|
}
|
|
|
|
remap_to_dest(clone, bio);
|
|
hydrate_bio_region(clone, bio);
|
|
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
static int clone_endio(struct dm_target *ti, struct bio *bio, blk_status_t *error)
|
|
{
|
|
struct clone *clone = ti->private;
|
|
|
|
atomic_dec(&clone->ios_in_flight);
|
|
|
|
return DM_ENDIO_DONE;
|
|
}
|
|
|
|
static void emit_flags(struct clone *clone, char *result, unsigned int maxlen,
|
|
ssize_t *sz_ptr)
|
|
{
|
|
ssize_t sz = *sz_ptr;
|
|
unsigned int count;
|
|
|
|
count = !test_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags);
|
|
count += !test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags);
|
|
|
|
DMEMIT("%u ", count);
|
|
|
|
if (!test_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags))
|
|
DMEMIT("no_hydration ");
|
|
|
|
if (!test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags))
|
|
DMEMIT("no_discard_passdown ");
|
|
|
|
*sz_ptr = sz;
|
|
}
|
|
|
|
static void emit_core_args(struct clone *clone, char *result,
|
|
unsigned int maxlen, ssize_t *sz_ptr)
|
|
{
|
|
ssize_t sz = *sz_ptr;
|
|
unsigned int count = 4;
|
|
|
|
DMEMIT("%u hydration_threshold %u hydration_batch_size %u ", count,
|
|
READ_ONCE(clone->hydration_threshold),
|
|
READ_ONCE(clone->hydration_batch_size));
|
|
|
|
*sz_ptr = sz;
|
|
}
|
|
|
|
/*
|
|
* Status format:
|
|
*
|
|
* <metadata block size> <#used metadata blocks>/<#total metadata blocks>
|
|
* <clone region size> <#hydrated regions>/<#total regions> <#hydrating regions>
|
|
* <#features> <features>* <#core args> <core args>* <clone metadata mode>
|
|
*/
|
|
static void clone_status(struct dm_target *ti, status_type_t type,
|
|
unsigned int status_flags, char *result,
|
|
unsigned int maxlen)
|
|
{
|
|
int r;
|
|
unsigned int i;
|
|
ssize_t sz = 0;
|
|
dm_block_t nr_free_metadata_blocks = 0;
|
|
dm_block_t nr_metadata_blocks = 0;
|
|
char buf[BDEVNAME_SIZE];
|
|
struct clone *clone = ti->private;
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
if (get_clone_mode(clone) == CM_FAIL) {
|
|
DMEMIT("Fail");
|
|
break;
|
|
}
|
|
|
|
/* Commit to ensure statistics aren't out-of-date */
|
|
if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
|
|
(void) commit_metadata(clone, NULL);
|
|
|
|
r = dm_clone_get_free_metadata_block_count(clone->cmd, &nr_free_metadata_blocks);
|
|
|
|
if (r) {
|
|
DMERR("%s: dm_clone_get_free_metadata_block_count returned %d",
|
|
clone_device_name(clone), r);
|
|
goto error;
|
|
}
|
|
|
|
r = dm_clone_get_metadata_dev_size(clone->cmd, &nr_metadata_blocks);
|
|
|
|
if (r) {
|
|
DMERR("%s: dm_clone_get_metadata_dev_size returned %d",
|
|
clone_device_name(clone), r);
|
|
goto error;
|
|
}
|
|
|
|
DMEMIT("%u %llu/%llu %llu %u/%lu %u ",
|
|
DM_CLONE_METADATA_BLOCK_SIZE,
|
|
(unsigned long long)(nr_metadata_blocks - nr_free_metadata_blocks),
|
|
(unsigned long long)nr_metadata_blocks,
|
|
(unsigned long long)clone->region_size,
|
|
dm_clone_nr_of_hydrated_regions(clone->cmd),
|
|
clone->nr_regions,
|
|
atomic_read(&clone->hydrations_in_flight));
|
|
|
|
emit_flags(clone, result, maxlen, &sz);
|
|
emit_core_args(clone, result, maxlen, &sz);
|
|
|
|
switch (get_clone_mode(clone)) {
|
|
case CM_WRITE:
|
|
DMEMIT("rw");
|
|
break;
|
|
case CM_READ_ONLY:
|
|
DMEMIT("ro");
|
|
break;
|
|
case CM_FAIL:
|
|
DMEMIT("Fail");
|
|
}
|
|
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
format_dev_t(buf, clone->metadata_dev->bdev->bd_dev);
|
|
DMEMIT("%s ", buf);
|
|
|
|
format_dev_t(buf, clone->dest_dev->bdev->bd_dev);
|
|
DMEMIT("%s ", buf);
|
|
|
|
format_dev_t(buf, clone->source_dev->bdev->bd_dev);
|
|
DMEMIT("%s", buf);
|
|
|
|
for (i = 0; i < clone->nr_ctr_args; i++)
|
|
DMEMIT(" %s", clone->ctr_args[i]);
|
|
break;
|
|
|
|
case STATUSTYPE_IMA:
|
|
*result = '\0';
|
|
break;
|
|
}
|
|
|
|
return;
|
|
|
|
error:
|
|
DMEMIT("Error");
|
|
}
|
|
|
|
static sector_t get_dev_size(struct dm_dev *dev)
|
|
{
|
|
return bdev_nr_sectors(dev->bdev);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Construct a clone device mapping:
|
|
*
|
|
* clone <metadata dev> <destination dev> <source dev> <region size>
|
|
* [<#feature args> [<feature arg>]* [<#core args> [key value]*]]
|
|
*
|
|
* metadata dev: Fast device holding the persistent metadata
|
|
* destination dev: The destination device, which will become a clone of the
|
|
* source device
|
|
* source dev: The read-only source device that gets cloned
|
|
* region size: dm-clone unit size in sectors
|
|
*
|
|
* #feature args: Number of feature arguments passed
|
|
* feature args: E.g. no_hydration, no_discard_passdown
|
|
*
|
|
* #core arguments: An even number of core arguments
|
|
* core arguments: Key/value pairs for tuning the core
|
|
* E.g. 'hydration_threshold 256'
|
|
*/
|
|
static int parse_feature_args(struct dm_arg_set *as, struct clone *clone)
|
|
{
|
|
int r;
|
|
unsigned int argc;
|
|
const char *arg_name;
|
|
struct dm_target *ti = clone->ti;
|
|
|
|
const struct dm_arg args = {
|
|
.min = 0,
|
|
.max = 2,
|
|
.error = "Invalid number of feature arguments"
|
|
};
|
|
|
|
/* No feature arguments supplied */
|
|
if (!as->argc)
|
|
return 0;
|
|
|
|
r = dm_read_arg_group(&args, as, &argc, &ti->error);
|
|
if (r)
|
|
return r;
|
|
|
|
while (argc) {
|
|
arg_name = dm_shift_arg(as);
|
|
argc--;
|
|
|
|
if (!strcasecmp(arg_name, "no_hydration")) {
|
|
__clear_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags);
|
|
} else if (!strcasecmp(arg_name, "no_discard_passdown")) {
|
|
__clear_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags);
|
|
} else {
|
|
ti->error = "Invalid feature argument";
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_core_args(struct dm_arg_set *as, struct clone *clone)
|
|
{
|
|
int r;
|
|
unsigned int argc;
|
|
unsigned int value;
|
|
const char *arg_name;
|
|
struct dm_target *ti = clone->ti;
|
|
|
|
const struct dm_arg args = {
|
|
.min = 0,
|
|
.max = 4,
|
|
.error = "Invalid number of core arguments"
|
|
};
|
|
|
|
/* Initialize core arguments */
|
|
clone->hydration_batch_size = DEFAULT_HYDRATION_BATCH_SIZE;
|
|
clone->hydration_threshold = DEFAULT_HYDRATION_THRESHOLD;
|
|
|
|
/* No core arguments supplied */
|
|
if (!as->argc)
|
|
return 0;
|
|
|
|
r = dm_read_arg_group(&args, as, &argc, &ti->error);
|
|
if (r)
|
|
return r;
|
|
|
|
if (argc & 1) {
|
|
ti->error = "Number of core arguments must be even";
|
|
return -EINVAL;
|
|
}
|
|
|
|
while (argc) {
|
|
arg_name = dm_shift_arg(as);
|
|
argc -= 2;
|
|
|
|
if (!strcasecmp(arg_name, "hydration_threshold")) {
|
|
if (kstrtouint(dm_shift_arg(as), 10, &value)) {
|
|
ti->error = "Invalid value for argument `hydration_threshold'";
|
|
return -EINVAL;
|
|
}
|
|
clone->hydration_threshold = value;
|
|
} else if (!strcasecmp(arg_name, "hydration_batch_size")) {
|
|
if (kstrtouint(dm_shift_arg(as), 10, &value)) {
|
|
ti->error = "Invalid value for argument `hydration_batch_size'";
|
|
return -EINVAL;
|
|
}
|
|
clone->hydration_batch_size = value;
|
|
} else {
|
|
ti->error = "Invalid core argument";
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_region_size(struct clone *clone, struct dm_arg_set *as, char **error)
|
|
{
|
|
int r;
|
|
unsigned int region_size;
|
|
struct dm_arg arg;
|
|
|
|
arg.min = MIN_REGION_SIZE;
|
|
arg.max = MAX_REGION_SIZE;
|
|
arg.error = "Invalid region size";
|
|
|
|
r = dm_read_arg(&arg, as, ®ion_size, error);
|
|
if (r)
|
|
return r;
|
|
|
|
/* Check region size is a power of 2 */
|
|
if (!is_power_of_2(region_size)) {
|
|
*error = "Region size is not a power of 2";
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Validate the region size against the device logical block size */
|
|
if (region_size % (bdev_logical_block_size(clone->source_dev->bdev) >> 9) ||
|
|
region_size % (bdev_logical_block_size(clone->dest_dev->bdev) >> 9)) {
|
|
*error = "Region size is not a multiple of device logical block size";
|
|
return -EINVAL;
|
|
}
|
|
|
|
clone->region_size = region_size;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int validate_nr_regions(unsigned long n, char **error)
|
|
{
|
|
/*
|
|
* dm_bitset restricts us to 2^32 regions. test_bit & co. restrict us
|
|
* further to 2^31 regions.
|
|
*/
|
|
if (n > (1UL << 31)) {
|
|
*error = "Too many regions. Consider increasing the region size";
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_metadata_dev(struct clone *clone, struct dm_arg_set *as, char **error)
|
|
{
|
|
int r;
|
|
sector_t metadata_dev_size;
|
|
|
|
r = dm_get_device(clone->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
|
|
&clone->metadata_dev);
|
|
if (r) {
|
|
*error = "Error opening metadata device";
|
|
return r;
|
|
}
|
|
|
|
metadata_dev_size = get_dev_size(clone->metadata_dev);
|
|
if (metadata_dev_size > DM_CLONE_METADATA_MAX_SECTORS_WARNING)
|
|
DMWARN("Metadata device %pg is larger than %u sectors: excess space will not be used.",
|
|
clone->metadata_dev->bdev, DM_CLONE_METADATA_MAX_SECTORS);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_dest_dev(struct clone *clone, struct dm_arg_set *as, char **error)
|
|
{
|
|
int r;
|
|
sector_t dest_dev_size;
|
|
|
|
r = dm_get_device(clone->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
|
|
&clone->dest_dev);
|
|
if (r) {
|
|
*error = "Error opening destination device";
|
|
return r;
|
|
}
|
|
|
|
dest_dev_size = get_dev_size(clone->dest_dev);
|
|
if (dest_dev_size < clone->ti->len) {
|
|
dm_put_device(clone->ti, clone->dest_dev);
|
|
*error = "Device size larger than destination device";
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_source_dev(struct clone *clone, struct dm_arg_set *as, char **error)
|
|
{
|
|
int r;
|
|
sector_t source_dev_size;
|
|
|
|
r = dm_get_device(clone->ti, dm_shift_arg(as), FMODE_READ,
|
|
&clone->source_dev);
|
|
if (r) {
|
|
*error = "Error opening source device";
|
|
return r;
|
|
}
|
|
|
|
source_dev_size = get_dev_size(clone->source_dev);
|
|
if (source_dev_size < clone->ti->len) {
|
|
dm_put_device(clone->ti, clone->source_dev);
|
|
*error = "Device size larger than source device";
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int copy_ctr_args(struct clone *clone, int argc, const char **argv, char **error)
|
|
{
|
|
unsigned int i;
|
|
const char **copy;
|
|
|
|
copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
|
|
if (!copy)
|
|
goto error;
|
|
|
|
for (i = 0; i < argc; i++) {
|
|
copy[i] = kstrdup(argv[i], GFP_KERNEL);
|
|
|
|
if (!copy[i]) {
|
|
while (i--)
|
|
kfree(copy[i]);
|
|
kfree(copy);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
clone->nr_ctr_args = argc;
|
|
clone->ctr_args = copy;
|
|
return 0;
|
|
|
|
error:
|
|
*error = "Failed to allocate memory for table line";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int clone_ctr(struct dm_target *ti, unsigned int argc, char **argv)
|
|
{
|
|
int r;
|
|
sector_t nr_regions;
|
|
struct clone *clone;
|
|
struct dm_arg_set as;
|
|
|
|
if (argc < 4) {
|
|
ti->error = "Invalid number of arguments";
|
|
return -EINVAL;
|
|
}
|
|
|
|
as.argc = argc;
|
|
as.argv = argv;
|
|
|
|
clone = kzalloc(sizeof(*clone), GFP_KERNEL);
|
|
if (!clone) {
|
|
ti->error = "Failed to allocate clone structure";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
clone->ti = ti;
|
|
|
|
/* Initialize dm-clone flags */
|
|
__set_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags);
|
|
__set_bit(DM_CLONE_HYDRATION_SUSPENDED, &clone->flags);
|
|
__set_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags);
|
|
|
|
r = parse_metadata_dev(clone, &as, &ti->error);
|
|
if (r)
|
|
goto out_with_clone;
|
|
|
|
r = parse_dest_dev(clone, &as, &ti->error);
|
|
if (r)
|
|
goto out_with_meta_dev;
|
|
|
|
r = parse_source_dev(clone, &as, &ti->error);
|
|
if (r)
|
|
goto out_with_dest_dev;
|
|
|
|
r = parse_region_size(clone, &as, &ti->error);
|
|
if (r)
|
|
goto out_with_source_dev;
|
|
|
|
clone->region_shift = __ffs(clone->region_size);
|
|
nr_regions = dm_sector_div_up(ti->len, clone->region_size);
|
|
|
|
/* Check for overflow */
|
|
if (nr_regions != (unsigned long)nr_regions) {
|
|
ti->error = "Too many regions. Consider increasing the region size";
|
|
r = -EOVERFLOW;
|
|
goto out_with_source_dev;
|
|
}
|
|
|
|
clone->nr_regions = nr_regions;
|
|
|
|
r = validate_nr_regions(clone->nr_regions, &ti->error);
|
|
if (r)
|
|
goto out_with_source_dev;
|
|
|
|
r = dm_set_target_max_io_len(ti, clone->region_size);
|
|
if (r) {
|
|
ti->error = "Failed to set max io len";
|
|
goto out_with_source_dev;
|
|
}
|
|
|
|
r = parse_feature_args(&as, clone);
|
|
if (r)
|
|
goto out_with_source_dev;
|
|
|
|
r = parse_core_args(&as, clone);
|
|
if (r)
|
|
goto out_with_source_dev;
|
|
|
|
/* Load metadata */
|
|
clone->cmd = dm_clone_metadata_open(clone->metadata_dev->bdev, ti->len,
|
|
clone->region_size);
|
|
if (IS_ERR(clone->cmd)) {
|
|
ti->error = "Failed to load metadata";
|
|
r = PTR_ERR(clone->cmd);
|
|
goto out_with_source_dev;
|
|
}
|
|
|
|
__set_clone_mode(clone, CM_WRITE);
|
|
|
|
if (get_clone_mode(clone) != CM_WRITE) {
|
|
ti->error = "Unable to get write access to metadata, please check/repair metadata";
|
|
r = -EPERM;
|
|
goto out_with_metadata;
|
|
}
|
|
|
|
clone->last_commit_jiffies = jiffies;
|
|
|
|
/* Allocate hydration hash table */
|
|
r = hash_table_init(clone);
|
|
if (r) {
|
|
ti->error = "Failed to allocate hydration hash table";
|
|
goto out_with_metadata;
|
|
}
|
|
|
|
atomic_set(&clone->ios_in_flight, 0);
|
|
init_waitqueue_head(&clone->hydration_stopped);
|
|
spin_lock_init(&clone->lock);
|
|
bio_list_init(&clone->deferred_bios);
|
|
bio_list_init(&clone->deferred_discard_bios);
|
|
bio_list_init(&clone->deferred_flush_bios);
|
|
bio_list_init(&clone->deferred_flush_completions);
|
|
clone->hydration_offset = 0;
|
|
atomic_set(&clone->hydrations_in_flight, 0);
|
|
|
|
clone->wq = alloc_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM, 0);
|
|
if (!clone->wq) {
|
|
ti->error = "Failed to allocate workqueue";
|
|
r = -ENOMEM;
|
|
goto out_with_ht;
|
|
}
|
|
|
|
INIT_WORK(&clone->worker, do_worker);
|
|
INIT_DELAYED_WORK(&clone->waker, do_waker);
|
|
|
|
clone->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
|
|
if (IS_ERR(clone->kcopyd_client)) {
|
|
r = PTR_ERR(clone->kcopyd_client);
|
|
goto out_with_wq;
|
|
}
|
|
|
|
r = mempool_init_slab_pool(&clone->hydration_pool, MIN_HYDRATIONS,
|
|
_hydration_cache);
|
|
if (r) {
|
|
ti->error = "Failed to create dm_clone_region_hydration memory pool";
|
|
goto out_with_kcopyd;
|
|
}
|
|
|
|
/* Save a copy of the table line */
|
|
r = copy_ctr_args(clone, argc - 3, (const char **)argv + 3, &ti->error);
|
|
if (r)
|
|
goto out_with_mempool;
|
|
|
|
mutex_init(&clone->commit_lock);
|
|
|
|
/* Enable flushes */
|
|
ti->num_flush_bios = 1;
|
|
ti->flush_supported = true;
|
|
|
|
/* Enable discards */
|
|
ti->discards_supported = true;
|
|
ti->num_discard_bios = 1;
|
|
|
|
ti->private = clone;
|
|
|
|
return 0;
|
|
|
|
out_with_mempool:
|
|
mempool_exit(&clone->hydration_pool);
|
|
out_with_kcopyd:
|
|
dm_kcopyd_client_destroy(clone->kcopyd_client);
|
|
out_with_wq:
|
|
destroy_workqueue(clone->wq);
|
|
out_with_ht:
|
|
hash_table_exit(clone);
|
|
out_with_metadata:
|
|
dm_clone_metadata_close(clone->cmd);
|
|
out_with_source_dev:
|
|
dm_put_device(ti, clone->source_dev);
|
|
out_with_dest_dev:
|
|
dm_put_device(ti, clone->dest_dev);
|
|
out_with_meta_dev:
|
|
dm_put_device(ti, clone->metadata_dev);
|
|
out_with_clone:
|
|
kfree(clone);
|
|
|
|
return r;
|
|
}
|
|
|
|
static void clone_dtr(struct dm_target *ti)
|
|
{
|
|
unsigned int i;
|
|
struct clone *clone = ti->private;
|
|
|
|
mutex_destroy(&clone->commit_lock);
|
|
|
|
for (i = 0; i < clone->nr_ctr_args; i++)
|
|
kfree(clone->ctr_args[i]);
|
|
kfree(clone->ctr_args);
|
|
|
|
mempool_exit(&clone->hydration_pool);
|
|
dm_kcopyd_client_destroy(clone->kcopyd_client);
|
|
cancel_delayed_work_sync(&clone->waker);
|
|
destroy_workqueue(clone->wq);
|
|
hash_table_exit(clone);
|
|
dm_clone_metadata_close(clone->cmd);
|
|
dm_put_device(ti, clone->source_dev);
|
|
dm_put_device(ti, clone->dest_dev);
|
|
dm_put_device(ti, clone->metadata_dev);
|
|
|
|
kfree(clone);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
static void clone_postsuspend(struct dm_target *ti)
|
|
{
|
|
struct clone *clone = ti->private;
|
|
|
|
/*
|
|
* To successfully suspend the device:
|
|
*
|
|
* - We cancel the delayed work for periodic commits and wait for
|
|
* it to finish.
|
|
*
|
|
* - We stop the background hydration, i.e. we prevent new region
|
|
* hydrations from starting.
|
|
*
|
|
* - We wait for any in-flight hydrations to finish.
|
|
*
|
|
* - We flush the workqueue.
|
|
*
|
|
* - We commit the metadata.
|
|
*/
|
|
cancel_delayed_work_sync(&clone->waker);
|
|
|
|
set_bit(DM_CLONE_HYDRATION_SUSPENDED, &clone->flags);
|
|
|
|
/*
|
|
* Make sure set_bit() is ordered before atomic_read(), otherwise we
|
|
* might race with do_hydration() and miss some started region
|
|
* hydrations.
|
|
*
|
|
* This is paired with smp_mb__after_atomic() in do_hydration().
|
|
*/
|
|
smp_mb__after_atomic();
|
|
|
|
wait_event(clone->hydration_stopped, !atomic_read(&clone->hydrations_in_flight));
|
|
flush_workqueue(clone->wq);
|
|
|
|
(void) commit_metadata(clone, NULL);
|
|
}
|
|
|
|
static void clone_resume(struct dm_target *ti)
|
|
{
|
|
struct clone *clone = ti->private;
|
|
|
|
clear_bit(DM_CLONE_HYDRATION_SUSPENDED, &clone->flags);
|
|
do_waker(&clone->waker.work);
|
|
}
|
|
|
|
/*
|
|
* If discard_passdown was enabled verify that the destination device supports
|
|
* discards. Disable discard_passdown if not.
|
|
*/
|
|
static void disable_passdown_if_not_supported(struct clone *clone)
|
|
{
|
|
struct block_device *dest_dev = clone->dest_dev->bdev;
|
|
struct queue_limits *dest_limits = &bdev_get_queue(dest_dev)->limits;
|
|
const char *reason = NULL;
|
|
|
|
if (!test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags))
|
|
return;
|
|
|
|
if (!bdev_max_discard_sectors(dest_dev))
|
|
reason = "discard unsupported";
|
|
else if (dest_limits->max_discard_sectors < clone->region_size)
|
|
reason = "max discard sectors smaller than a region";
|
|
|
|
if (reason) {
|
|
DMWARN("Destination device (%pg) %s: Disabling discard passdown.",
|
|
dest_dev, reason);
|
|
clear_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags);
|
|
}
|
|
}
|
|
|
|
static void set_discard_limits(struct clone *clone, struct queue_limits *limits)
|
|
{
|
|
struct block_device *dest_bdev = clone->dest_dev->bdev;
|
|
struct queue_limits *dest_limits = &bdev_get_queue(dest_bdev)->limits;
|
|
|
|
if (!test_bit(DM_CLONE_DISCARD_PASSDOWN, &clone->flags)) {
|
|
/* No passdown is done so we set our own virtual limits */
|
|
limits->discard_granularity = clone->region_size << SECTOR_SHIFT;
|
|
limits->max_discard_sectors = round_down(UINT_MAX >> SECTOR_SHIFT, clone->region_size);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* clone_iterate_devices() is stacking both the source and destination
|
|
* device limits but discards aren't passed to the source device, so
|
|
* inherit destination's limits.
|
|
*/
|
|
limits->max_discard_sectors = dest_limits->max_discard_sectors;
|
|
limits->max_hw_discard_sectors = dest_limits->max_hw_discard_sectors;
|
|
limits->discard_granularity = dest_limits->discard_granularity;
|
|
limits->discard_alignment = dest_limits->discard_alignment;
|
|
limits->discard_misaligned = dest_limits->discard_misaligned;
|
|
limits->max_discard_segments = dest_limits->max_discard_segments;
|
|
}
|
|
|
|
static void clone_io_hints(struct dm_target *ti, struct queue_limits *limits)
|
|
{
|
|
struct clone *clone = ti->private;
|
|
u64 io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
|
|
|
|
/*
|
|
* If the system-determined stacked limits are compatible with
|
|
* dm-clone's region size (io_opt is a factor) do not override them.
|
|
*/
|
|
if (io_opt_sectors < clone->region_size ||
|
|
do_div(io_opt_sectors, clone->region_size)) {
|
|
blk_limits_io_min(limits, clone->region_size << SECTOR_SHIFT);
|
|
blk_limits_io_opt(limits, clone->region_size << SECTOR_SHIFT);
|
|
}
|
|
|
|
disable_passdown_if_not_supported(clone);
|
|
set_discard_limits(clone, limits);
|
|
}
|
|
|
|
static int clone_iterate_devices(struct dm_target *ti,
|
|
iterate_devices_callout_fn fn, void *data)
|
|
{
|
|
int ret;
|
|
struct clone *clone = ti->private;
|
|
struct dm_dev *dest_dev = clone->dest_dev;
|
|
struct dm_dev *source_dev = clone->source_dev;
|
|
|
|
ret = fn(ti, source_dev, 0, ti->len, data);
|
|
if (!ret)
|
|
ret = fn(ti, dest_dev, 0, ti->len, data);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* dm-clone message functions.
|
|
*/
|
|
static void set_hydration_threshold(struct clone *clone, unsigned int nr_regions)
|
|
{
|
|
WRITE_ONCE(clone->hydration_threshold, nr_regions);
|
|
|
|
/*
|
|
* If user space sets hydration_threshold to zero then the hydration
|
|
* will stop. If at a later time the hydration_threshold is increased
|
|
* we must restart the hydration process by waking up the worker.
|
|
*/
|
|
wake_worker(clone);
|
|
}
|
|
|
|
static void set_hydration_batch_size(struct clone *clone, unsigned int nr_regions)
|
|
{
|
|
WRITE_ONCE(clone->hydration_batch_size, nr_regions);
|
|
}
|
|
|
|
static void enable_hydration(struct clone *clone)
|
|
{
|
|
if (!test_and_set_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags))
|
|
wake_worker(clone);
|
|
}
|
|
|
|
static void disable_hydration(struct clone *clone)
|
|
{
|
|
clear_bit(DM_CLONE_HYDRATION_ENABLED, &clone->flags);
|
|
}
|
|
|
|
static int clone_message(struct dm_target *ti, unsigned int argc, char **argv,
|
|
char *result, unsigned int maxlen)
|
|
{
|
|
struct clone *clone = ti->private;
|
|
unsigned int value;
|
|
|
|
if (!argc)
|
|
return -EINVAL;
|
|
|
|
if (!strcasecmp(argv[0], "enable_hydration")) {
|
|
enable_hydration(clone);
|
|
return 0;
|
|
}
|
|
|
|
if (!strcasecmp(argv[0], "disable_hydration")) {
|
|
disable_hydration(clone);
|
|
return 0;
|
|
}
|
|
|
|
if (argc != 2)
|
|
return -EINVAL;
|
|
|
|
if (!strcasecmp(argv[0], "hydration_threshold")) {
|
|
if (kstrtouint(argv[1], 10, &value))
|
|
return -EINVAL;
|
|
|
|
set_hydration_threshold(clone, value);
|
|
|
|
return 0;
|
|
}
|
|
|
|
if (!strcasecmp(argv[0], "hydration_batch_size")) {
|
|
if (kstrtouint(argv[1], 10, &value))
|
|
return -EINVAL;
|
|
|
|
set_hydration_batch_size(clone, value);
|
|
|
|
return 0;
|
|
}
|
|
|
|
DMERR("%s: Unsupported message `%s'", clone_device_name(clone), argv[0]);
|
|
return -EINVAL;
|
|
}
|
|
|
|
static struct target_type clone_target = {
|
|
.name = "clone",
|
|
.version = {1, 0, 0},
|
|
.module = THIS_MODULE,
|
|
.ctr = clone_ctr,
|
|
.dtr = clone_dtr,
|
|
.map = clone_map,
|
|
.end_io = clone_endio,
|
|
.postsuspend = clone_postsuspend,
|
|
.resume = clone_resume,
|
|
.status = clone_status,
|
|
.message = clone_message,
|
|
.io_hints = clone_io_hints,
|
|
.iterate_devices = clone_iterate_devices,
|
|
};
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/* Module functions */
|
|
static int __init dm_clone_init(void)
|
|
{
|
|
int r;
|
|
|
|
_hydration_cache = KMEM_CACHE(dm_clone_region_hydration, 0);
|
|
if (!_hydration_cache)
|
|
return -ENOMEM;
|
|
|
|
r = dm_register_target(&clone_target);
|
|
if (r < 0) {
|
|
DMERR("Failed to register clone target");
|
|
return r;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit dm_clone_exit(void)
|
|
{
|
|
dm_unregister_target(&clone_target);
|
|
|
|
kmem_cache_destroy(_hydration_cache);
|
|
_hydration_cache = NULL;
|
|
}
|
|
|
|
/* Module hooks */
|
|
module_init(dm_clone_init);
|
|
module_exit(dm_clone_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " clone target");
|
|
MODULE_AUTHOR("Nikos Tsironis <ntsironis@arrikto.com>");
|
|
MODULE_LICENSE("GPL");
|