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![Mike Snitzer](/assets/img/avatar_default.png)
Before, if the block layer's limit stacking didn't establish an optimal_io_size that was compatible with the cache's data block size we'd set optimal_io_size to the data block size and minimum_io_size to 0 (which the block layer adjusts to be physical_block_size). Update cache_io_hints() to set both minimum_io_size and optimal_io_size to the cache's data block size. This fixes an issue where mkfs.xfs would create more XFS Allocation Groups on cache volumes than on a normal linear LV of comparable size. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
3153 lines
76 KiB
C
3153 lines
76 KiB
C
/*
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* Copyright (C) 2012 Red Hat. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include "dm.h"
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#include "dm-bio-prison.h"
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#include "dm-bio-record.h"
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#include "dm-cache-metadata.h"
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#include <linux/dm-io.h>
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#include <linux/dm-kcopyd.h>
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#include <linux/init.h>
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#include <linux/mempool.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#define DM_MSG_PREFIX "cache"
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DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle,
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"A percentage of time allocated for copying to and/or from cache");
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/*----------------------------------------------------------------*/
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/*
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* Glossary:
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*
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* oblock: index of an origin block
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* cblock: index of a cache block
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* promotion: movement of a block from origin to cache
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* demotion: movement of a block from cache to origin
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* migration: movement of a block between the origin and cache device,
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* either direction
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*/
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/*----------------------------------------------------------------*/
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static size_t bitset_size_in_bytes(unsigned nr_entries)
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{
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return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
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}
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static unsigned long *alloc_bitset(unsigned nr_entries)
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{
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size_t s = bitset_size_in_bytes(nr_entries);
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return vzalloc(s);
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}
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static void clear_bitset(void *bitset, unsigned nr_entries)
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{
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size_t s = bitset_size_in_bytes(nr_entries);
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memset(bitset, 0, s);
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}
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static void free_bitset(unsigned long *bits)
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{
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vfree(bits);
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}
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/*----------------------------------------------------------------*/
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/*
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* There are a couple of places where we let a bio run, but want to do some
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* work before calling its endio function. We do this by temporarily
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* changing the endio fn.
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*/
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struct dm_hook_info {
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bio_end_io_t *bi_end_io;
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void *bi_private;
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};
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static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio,
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bio_end_io_t *bi_end_io, void *bi_private)
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{
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h->bi_end_io = bio->bi_end_io;
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h->bi_private = bio->bi_private;
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bio->bi_end_io = bi_end_io;
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bio->bi_private = bi_private;
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}
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static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio)
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{
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bio->bi_end_io = h->bi_end_io;
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bio->bi_private = h->bi_private;
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/*
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* Must bump bi_remaining to allow bio to complete with
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* restored bi_end_io.
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*/
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atomic_inc(&bio->bi_remaining);
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}
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/*----------------------------------------------------------------*/
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#define PRISON_CELLS 1024
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#define MIGRATION_POOL_SIZE 128
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#define COMMIT_PERIOD HZ
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#define MIGRATION_COUNT_WINDOW 10
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/*
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* The block size of the device holding cache data must be
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* between 32KB and 1GB.
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*/
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#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
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#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
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/*
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* FIXME: the cache is read/write for the time being.
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*/
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enum cache_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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};
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enum cache_io_mode {
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/*
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* Data is written to cached blocks only. These blocks are marked
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* dirty. If you lose the cache device you will lose data.
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* Potential performance increase for both reads and writes.
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*/
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CM_IO_WRITEBACK,
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/*
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* Data is written to both cache and origin. Blocks are never
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* dirty. Potential performance benfit for reads only.
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*/
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CM_IO_WRITETHROUGH,
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/*
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* A degraded mode useful for various cache coherency situations
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* (eg, rolling back snapshots). Reads and writes always go to the
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* origin. If a write goes to a cached oblock, then the cache
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* block is invalidated.
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*/
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CM_IO_PASSTHROUGH
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};
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struct cache_features {
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enum cache_metadata_mode mode;
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enum cache_io_mode io_mode;
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};
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struct cache_stats {
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atomic_t read_hit;
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atomic_t read_miss;
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atomic_t write_hit;
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atomic_t write_miss;
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atomic_t demotion;
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atomic_t promotion;
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atomic_t copies_avoided;
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atomic_t cache_cell_clash;
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atomic_t commit_count;
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atomic_t discard_count;
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};
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/*
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* Defines a range of cblocks, begin to (end - 1) are in the range. end is
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* the one-past-the-end value.
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*/
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struct cblock_range {
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dm_cblock_t begin;
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dm_cblock_t end;
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};
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struct invalidation_request {
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struct list_head list;
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struct cblock_range *cblocks;
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atomic_t complete;
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int err;
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wait_queue_head_t result_wait;
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};
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struct cache {
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struct dm_target *ti;
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struct dm_target_callbacks callbacks;
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struct dm_cache_metadata *cmd;
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/*
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* Metadata is written to this device.
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*/
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struct dm_dev *metadata_dev;
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/*
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* The slower of the two data devices. Typically a spindle.
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*/
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struct dm_dev *origin_dev;
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/*
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* The faster of the two data devices. Typically an SSD.
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*/
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struct dm_dev *cache_dev;
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/*
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* Size of the origin device in _complete_ blocks and native sectors.
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*/
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dm_oblock_t origin_blocks;
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sector_t origin_sectors;
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/*
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* Size of the cache device in blocks.
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*/
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dm_cblock_t cache_size;
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/*
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* Fields for converting from sectors to blocks.
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*/
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uint32_t sectors_per_block;
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int sectors_per_block_shift;
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spinlock_t lock;
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struct bio_list deferred_bios;
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struct bio_list deferred_flush_bios;
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struct bio_list deferred_writethrough_bios;
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struct list_head quiesced_migrations;
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struct list_head completed_migrations;
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struct list_head need_commit_migrations;
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sector_t migration_threshold;
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wait_queue_head_t migration_wait;
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atomic_t nr_migrations;
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wait_queue_head_t quiescing_wait;
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atomic_t quiescing;
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atomic_t quiescing_ack;
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/*
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* cache_size entries, dirty if set
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*/
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atomic_t nr_dirty;
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unsigned long *dirty_bitset;
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/*
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* origin_blocks entries, discarded if set.
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*/
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dm_oblock_t discard_nr_blocks;
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unsigned long *discard_bitset;
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/*
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* Rather than reconstructing the table line for the status we just
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* save it and regurgitate.
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*/
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unsigned nr_ctr_args;
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const char **ctr_args;
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struct dm_kcopyd_client *copier;
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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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unsigned long last_commit_jiffies;
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struct dm_bio_prison *prison;
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struct dm_deferred_set *all_io_ds;
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mempool_t *migration_pool;
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struct dm_cache_migration *next_migration;
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struct dm_cache_policy *policy;
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unsigned policy_nr_args;
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bool need_tick_bio:1;
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bool sized:1;
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bool invalidate:1;
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bool commit_requested:1;
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bool loaded_mappings:1;
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bool loaded_discards:1;
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/*
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* Cache features such as write-through.
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*/
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struct cache_features features;
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struct cache_stats stats;
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/*
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* Invalidation fields.
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*/
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spinlock_t invalidation_lock;
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struct list_head invalidation_requests;
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};
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struct per_bio_data {
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bool tick:1;
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unsigned req_nr:2;
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struct dm_deferred_entry *all_io_entry;
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struct dm_hook_info hook_info;
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/*
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* writethrough fields. These MUST remain at the end of this
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* structure and the 'cache' member must be the first as it
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* is used to determine the offset of the writethrough fields.
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*/
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struct cache *cache;
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dm_cblock_t cblock;
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struct dm_bio_details bio_details;
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};
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struct dm_cache_migration {
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struct list_head list;
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struct cache *cache;
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unsigned long start_jiffies;
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dm_oblock_t old_oblock;
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dm_oblock_t new_oblock;
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dm_cblock_t cblock;
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bool err:1;
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bool writeback:1;
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bool demote:1;
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bool promote:1;
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bool requeue_holder:1;
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bool invalidate:1;
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struct dm_bio_prison_cell *old_ocell;
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struct dm_bio_prison_cell *new_ocell;
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};
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/*
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* Processing a bio in the worker thread may require these memory
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* allocations. We prealloc to avoid deadlocks (the same worker thread
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* frees them back to the mempool).
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*/
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struct prealloc {
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struct dm_cache_migration *mg;
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struct dm_bio_prison_cell *cell1;
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struct dm_bio_prison_cell *cell2;
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};
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static void wake_worker(struct cache *cache)
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{
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queue_work(cache->wq, &cache->worker);
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}
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/*----------------------------------------------------------------*/
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static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache)
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{
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/* FIXME: change to use a local slab. */
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return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT);
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}
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static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell)
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{
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dm_bio_prison_free_cell(cache->prison, cell);
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}
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static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
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{
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if (!p->mg) {
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p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
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if (!p->mg)
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return -ENOMEM;
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}
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if (!p->cell1) {
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p->cell1 = alloc_prison_cell(cache);
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if (!p->cell1)
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return -ENOMEM;
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}
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if (!p->cell2) {
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p->cell2 = alloc_prison_cell(cache);
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if (!p->cell2)
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return -ENOMEM;
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}
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return 0;
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}
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static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
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{
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if (p->cell2)
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free_prison_cell(cache, p->cell2);
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if (p->cell1)
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free_prison_cell(cache, p->cell1);
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if (p->mg)
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mempool_free(p->mg, cache->migration_pool);
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}
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static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
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{
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struct dm_cache_migration *mg = p->mg;
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BUG_ON(!mg);
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p->mg = NULL;
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return mg;
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}
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/*
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* You must have a cell within the prealloc struct to return. If not this
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* function will BUG() rather than returning NULL.
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*/
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static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p)
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{
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struct dm_bio_prison_cell *r = NULL;
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if (p->cell1) {
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r = p->cell1;
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p->cell1 = NULL;
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} else if (p->cell2) {
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r = p->cell2;
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p->cell2 = NULL;
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} else
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BUG();
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return r;
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}
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/*
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* You can't have more than two cells in a prealloc struct. BUG() will be
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* called if you try and overfill.
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*/
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static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell)
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{
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if (!p->cell2)
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p->cell2 = cell;
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else if (!p->cell1)
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p->cell1 = cell;
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else
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BUG();
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}
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/*----------------------------------------------------------------*/
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static void build_key(dm_oblock_t oblock, struct dm_cell_key *key)
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{
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key->virtual = 0;
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key->dev = 0;
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key->block = from_oblock(oblock);
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}
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/*
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* The caller hands in a preallocated cell, and a free function for it.
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* The cell will be freed if there's an error, or if it wasn't used because
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* a cell with that key already exists.
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*/
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typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell);
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static int bio_detain(struct cache *cache, dm_oblock_t oblock,
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struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
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cell_free_fn free_fn, void *free_context,
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struct dm_bio_prison_cell **cell_result)
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{
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int r;
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struct dm_cell_key key;
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build_key(oblock, &key);
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r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result);
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if (r)
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free_fn(free_context, cell_prealloc);
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return r;
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}
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static int get_cell(struct cache *cache,
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dm_oblock_t oblock,
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struct prealloc *structs,
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struct dm_bio_prison_cell **cell_result)
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{
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int r;
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struct dm_cell_key key;
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struct dm_bio_prison_cell *cell_prealloc;
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cell_prealloc = prealloc_get_cell(structs);
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build_key(oblock, &key);
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r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result);
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if (r)
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prealloc_put_cell(structs, cell_prealloc);
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return r;
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}
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/*----------------------------------------------------------------*/
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static bool is_dirty(struct cache *cache, dm_cblock_t b)
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{
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return test_bit(from_cblock(b), cache->dirty_bitset);
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}
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static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
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{
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if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
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atomic_inc(&cache->nr_dirty);
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policy_set_dirty(cache->policy, oblock);
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}
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}
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static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
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{
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if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
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policy_clear_dirty(cache->policy, oblock);
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if (atomic_dec_return(&cache->nr_dirty) == 0)
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dm_table_event(cache->ti->table);
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}
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}
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/*----------------------------------------------------------------*/
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static bool block_size_is_power_of_two(struct cache *cache)
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{
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return cache->sectors_per_block_shift >= 0;
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}
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/* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
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#if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6
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__always_inline
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#endif
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static dm_block_t block_div(dm_block_t b, uint32_t n)
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{
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do_div(b, n);
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return b;
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}
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static void set_discard(struct cache *cache, dm_oblock_t b)
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{
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unsigned long flags;
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atomic_inc(&cache->stats.discard_count);
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spin_lock_irqsave(&cache->lock, flags);
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set_bit(from_oblock(b), cache->discard_bitset);
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spin_unlock_irqrestore(&cache->lock, flags);
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}
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static void clear_discard(struct cache *cache, dm_oblock_t b)
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{
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unsigned long flags;
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spin_lock_irqsave(&cache->lock, flags);
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clear_bit(from_oblock(b), cache->discard_bitset);
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spin_unlock_irqrestore(&cache->lock, flags);
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}
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static bool is_discarded(struct cache *cache, dm_oblock_t b)
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{
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int r;
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unsigned long flags;
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spin_lock_irqsave(&cache->lock, flags);
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r = test_bit(from_oblock(b), cache->discard_bitset);
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spin_unlock_irqrestore(&cache->lock, flags);
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return r;
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|
}
|
|
|
|
static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
|
|
{
|
|
int r;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
r = test_bit(from_oblock(b), cache->discard_bitset);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
static void load_stats(struct cache *cache)
|
|
{
|
|
struct dm_cache_statistics stats;
|
|
|
|
dm_cache_metadata_get_stats(cache->cmd, &stats);
|
|
atomic_set(&cache->stats.read_hit, stats.read_hits);
|
|
atomic_set(&cache->stats.read_miss, stats.read_misses);
|
|
atomic_set(&cache->stats.write_hit, stats.write_hits);
|
|
atomic_set(&cache->stats.write_miss, stats.write_misses);
|
|
}
|
|
|
|
static void save_stats(struct cache *cache)
|
|
{
|
|
struct dm_cache_statistics stats;
|
|
|
|
stats.read_hits = atomic_read(&cache->stats.read_hit);
|
|
stats.read_misses = atomic_read(&cache->stats.read_miss);
|
|
stats.write_hits = atomic_read(&cache->stats.write_hit);
|
|
stats.write_misses = atomic_read(&cache->stats.write_miss);
|
|
|
|
dm_cache_metadata_set_stats(cache->cmd, &stats);
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* Per bio data
|
|
*--------------------------------------------------------------*/
|
|
|
|
/*
|
|
* If using writeback, leave out struct per_bio_data's writethrough fields.
|
|
*/
|
|
#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
|
|
#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
|
|
|
|
static bool writethrough_mode(struct cache_features *f)
|
|
{
|
|
return f->io_mode == CM_IO_WRITETHROUGH;
|
|
}
|
|
|
|
static bool writeback_mode(struct cache_features *f)
|
|
{
|
|
return f->io_mode == CM_IO_WRITEBACK;
|
|
}
|
|
|
|
static bool passthrough_mode(struct cache_features *f)
|
|
{
|
|
return f->io_mode == CM_IO_PASSTHROUGH;
|
|
}
|
|
|
|
static size_t get_per_bio_data_size(struct cache *cache)
|
|
{
|
|
return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
|
|
}
|
|
|
|
static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
|
|
{
|
|
struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
|
|
BUG_ON(!pb);
|
|
return pb;
|
|
}
|
|
|
|
static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
|
|
{
|
|
struct per_bio_data *pb = get_per_bio_data(bio, data_size);
|
|
|
|
pb->tick = false;
|
|
pb->req_nr = dm_bio_get_target_bio_nr(bio);
|
|
pb->all_io_entry = NULL;
|
|
|
|
return pb;
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* Remapping
|
|
*--------------------------------------------------------------*/
|
|
static void remap_to_origin(struct cache *cache, struct bio *bio)
|
|
{
|
|
bio->bi_bdev = cache->origin_dev->bdev;
|
|
}
|
|
|
|
static void remap_to_cache(struct cache *cache, struct bio *bio,
|
|
dm_cblock_t cblock)
|
|
{
|
|
sector_t bi_sector = bio->bi_iter.bi_sector;
|
|
sector_t block = from_cblock(cblock);
|
|
|
|
bio->bi_bdev = cache->cache_dev->bdev;
|
|
if (!block_size_is_power_of_two(cache))
|
|
bio->bi_iter.bi_sector =
|
|
(block * cache->sectors_per_block) +
|
|
sector_div(bi_sector, cache->sectors_per_block);
|
|
else
|
|
bio->bi_iter.bi_sector =
|
|
(block << cache->sectors_per_block_shift) |
|
|
(bi_sector & (cache->sectors_per_block - 1));
|
|
}
|
|
|
|
static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
|
|
{
|
|
unsigned long flags;
|
|
size_t pb_data_size = get_per_bio_data_size(cache);
|
|
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
if (cache->need_tick_bio &&
|
|
!(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
|
|
pb->tick = true;
|
|
cache->need_tick_bio = false;
|
|
}
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
}
|
|
|
|
static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
|
|
dm_oblock_t oblock)
|
|
{
|
|
check_if_tick_bio_needed(cache, bio);
|
|
remap_to_origin(cache, bio);
|
|
if (bio_data_dir(bio) == WRITE)
|
|
clear_discard(cache, oblock);
|
|
}
|
|
|
|
static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
|
|
dm_oblock_t oblock, dm_cblock_t cblock)
|
|
{
|
|
check_if_tick_bio_needed(cache, bio);
|
|
remap_to_cache(cache, bio, cblock);
|
|
if (bio_data_dir(bio) == WRITE) {
|
|
set_dirty(cache, oblock, cblock);
|
|
clear_discard(cache, oblock);
|
|
}
|
|
}
|
|
|
|
static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
|
|
{
|
|
sector_t block_nr = bio->bi_iter.bi_sector;
|
|
|
|
if (!block_size_is_power_of_two(cache))
|
|
(void) sector_div(block_nr, cache->sectors_per_block);
|
|
else
|
|
block_nr >>= cache->sectors_per_block_shift;
|
|
|
|
return to_oblock(block_nr);
|
|
}
|
|
|
|
static int bio_triggers_commit(struct cache *cache, struct bio *bio)
|
|
{
|
|
return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
|
|
}
|
|
|
|
/*
|
|
* You must increment the deferred set whilst the prison cell is held. To
|
|
* encourage this, we ask for 'cell' to be passed in.
|
|
*/
|
|
static void inc_ds(struct cache *cache, struct bio *bio,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
size_t pb_data_size = get_per_bio_data_size(cache);
|
|
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
|
|
|
|
BUG_ON(!cell);
|
|
BUG_ON(pb->all_io_entry);
|
|
|
|
pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
|
|
}
|
|
|
|
static void issue(struct cache *cache, struct bio *bio)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!bio_triggers_commit(cache, bio)) {
|
|
generic_make_request(bio);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Batch together any bios that trigger commits and then issue a
|
|
* single commit for them in do_worker().
|
|
*/
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
cache->commit_requested = true;
|
|
bio_list_add(&cache->deferred_flush_bios, bio);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
}
|
|
|
|
static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell)
|
|
{
|
|
inc_ds(cache, bio, cell);
|
|
issue(cache, bio);
|
|
}
|
|
|
|
static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
bio_list_add(&cache->deferred_writethrough_bios, bio);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void writethrough_endio(struct bio *bio, int err)
|
|
{
|
|
struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
|
|
|
|
dm_unhook_bio(&pb->hook_info, bio);
|
|
|
|
if (err) {
|
|
bio_endio(bio, err);
|
|
return;
|
|
}
|
|
|
|
dm_bio_restore(&pb->bio_details, bio);
|
|
remap_to_cache(pb->cache, bio, pb->cblock);
|
|
|
|
/*
|
|
* We can't issue this bio directly, since we're in interrupt
|
|
* context. So it gets put on a bio list for processing by the
|
|
* worker thread.
|
|
*/
|
|
defer_writethrough_bio(pb->cache, bio);
|
|
}
|
|
|
|
/*
|
|
* When running in writethrough mode we need to send writes to clean blocks
|
|
* to both the cache and origin devices. In future we'd like to clone the
|
|
* bio and send them in parallel, but for now we're doing them in
|
|
* series as this is easier.
|
|
*/
|
|
static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
|
|
dm_oblock_t oblock, dm_cblock_t cblock)
|
|
{
|
|
struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
|
|
|
|
pb->cache = cache;
|
|
pb->cblock = cblock;
|
|
dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL);
|
|
dm_bio_record(&pb->bio_details, bio);
|
|
|
|
remap_to_origin_clear_discard(pb->cache, bio, oblock);
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* Migration processing
|
|
*
|
|
* Migration covers moving data from the origin device to the cache, or
|
|
* vice versa.
|
|
*--------------------------------------------------------------*/
|
|
static void free_migration(struct dm_cache_migration *mg)
|
|
{
|
|
mempool_free(mg, mg->cache->migration_pool);
|
|
}
|
|
|
|
static void inc_nr_migrations(struct cache *cache)
|
|
{
|
|
atomic_inc(&cache->nr_migrations);
|
|
}
|
|
|
|
static void dec_nr_migrations(struct cache *cache)
|
|
{
|
|
atomic_dec(&cache->nr_migrations);
|
|
|
|
/*
|
|
* Wake the worker in case we're suspending the target.
|
|
*/
|
|
wake_up(&cache->migration_wait);
|
|
}
|
|
|
|
static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
|
|
bool holder)
|
|
{
|
|
(holder ? dm_cell_release : dm_cell_release_no_holder)
|
|
(cache->prison, cell, &cache->deferred_bios);
|
|
free_prison_cell(cache, cell);
|
|
}
|
|
|
|
static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
|
|
bool holder)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
__cell_defer(cache, cell, holder);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void cleanup_migration(struct dm_cache_migration *mg)
|
|
{
|
|
struct cache *cache = mg->cache;
|
|
free_migration(mg);
|
|
dec_nr_migrations(cache);
|
|
}
|
|
|
|
static void migration_failure(struct dm_cache_migration *mg)
|
|
{
|
|
struct cache *cache = mg->cache;
|
|
|
|
if (mg->writeback) {
|
|
DMWARN_LIMIT("writeback failed; couldn't copy block");
|
|
set_dirty(cache, mg->old_oblock, mg->cblock);
|
|
cell_defer(cache, mg->old_ocell, false);
|
|
|
|
} else if (mg->demote) {
|
|
DMWARN_LIMIT("demotion failed; couldn't copy block");
|
|
policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
|
|
|
|
cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
|
|
if (mg->promote)
|
|
cell_defer(cache, mg->new_ocell, true);
|
|
} else {
|
|
DMWARN_LIMIT("promotion failed; couldn't copy block");
|
|
policy_remove_mapping(cache->policy, mg->new_oblock);
|
|
cell_defer(cache, mg->new_ocell, true);
|
|
}
|
|
|
|
cleanup_migration(mg);
|
|
}
|
|
|
|
static void migration_success_pre_commit(struct dm_cache_migration *mg)
|
|
{
|
|
unsigned long flags;
|
|
struct cache *cache = mg->cache;
|
|
|
|
if (mg->writeback) {
|
|
cell_defer(cache, mg->old_ocell, false);
|
|
clear_dirty(cache, mg->old_oblock, mg->cblock);
|
|
cleanup_migration(mg);
|
|
return;
|
|
|
|
} else if (mg->demote) {
|
|
if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) {
|
|
DMWARN_LIMIT("demotion failed; couldn't update on disk metadata");
|
|
policy_force_mapping(cache->policy, mg->new_oblock,
|
|
mg->old_oblock);
|
|
if (mg->promote)
|
|
cell_defer(cache, mg->new_ocell, true);
|
|
cleanup_migration(mg);
|
|
return;
|
|
}
|
|
} else {
|
|
if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) {
|
|
DMWARN_LIMIT("promotion failed; couldn't update on disk metadata");
|
|
policy_remove_mapping(cache->policy, mg->new_oblock);
|
|
cleanup_migration(mg);
|
|
return;
|
|
}
|
|
}
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
list_add_tail(&mg->list, &cache->need_commit_migrations);
|
|
cache->commit_requested = true;
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
}
|
|
|
|
static void migration_success_post_commit(struct dm_cache_migration *mg)
|
|
{
|
|
unsigned long flags;
|
|
struct cache *cache = mg->cache;
|
|
|
|
if (mg->writeback) {
|
|
DMWARN("writeback unexpectedly triggered commit");
|
|
return;
|
|
|
|
} else if (mg->demote) {
|
|
cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
|
|
|
|
if (mg->promote) {
|
|
mg->demote = false;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
list_add_tail(&mg->list, &cache->quiesced_migrations);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
} else {
|
|
if (mg->invalidate)
|
|
policy_remove_mapping(cache->policy, mg->old_oblock);
|
|
cleanup_migration(mg);
|
|
}
|
|
|
|
} else {
|
|
if (mg->requeue_holder)
|
|
cell_defer(cache, mg->new_ocell, true);
|
|
else {
|
|
bio_endio(mg->new_ocell->holder, 0);
|
|
cell_defer(cache, mg->new_ocell, false);
|
|
}
|
|
clear_dirty(cache, mg->new_oblock, mg->cblock);
|
|
cleanup_migration(mg);
|
|
}
|
|
}
|
|
|
|
static void copy_complete(int read_err, unsigned long write_err, void *context)
|
|
{
|
|
unsigned long flags;
|
|
struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
|
|
struct cache *cache = mg->cache;
|
|
|
|
if (read_err || write_err)
|
|
mg->err = true;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
list_add_tail(&mg->list, &cache->completed_migrations);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void issue_copy_real(struct dm_cache_migration *mg)
|
|
{
|
|
int r;
|
|
struct dm_io_region o_region, c_region;
|
|
struct cache *cache = mg->cache;
|
|
sector_t cblock = from_cblock(mg->cblock);
|
|
|
|
o_region.bdev = cache->origin_dev->bdev;
|
|
o_region.count = cache->sectors_per_block;
|
|
|
|
c_region.bdev = cache->cache_dev->bdev;
|
|
c_region.sector = cblock * cache->sectors_per_block;
|
|
c_region.count = cache->sectors_per_block;
|
|
|
|
if (mg->writeback || mg->demote) {
|
|
/* demote */
|
|
o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
|
|
r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
|
|
} else {
|
|
/* promote */
|
|
o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
|
|
r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
|
|
}
|
|
|
|
if (r < 0) {
|
|
DMERR_LIMIT("issuing migration failed");
|
|
migration_failure(mg);
|
|
}
|
|
}
|
|
|
|
static void overwrite_endio(struct bio *bio, int err)
|
|
{
|
|
struct dm_cache_migration *mg = bio->bi_private;
|
|
struct cache *cache = mg->cache;
|
|
size_t pb_data_size = get_per_bio_data_size(cache);
|
|
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
|
|
unsigned long flags;
|
|
|
|
dm_unhook_bio(&pb->hook_info, bio);
|
|
|
|
if (err)
|
|
mg->err = true;
|
|
|
|
mg->requeue_holder = false;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
list_add_tail(&mg->list, &cache->completed_migrations);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio)
|
|
{
|
|
size_t pb_data_size = get_per_bio_data_size(mg->cache);
|
|
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
|
|
|
|
dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
|
|
remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
|
|
|
|
/*
|
|
* No need to inc_ds() here, since the cell will be held for the
|
|
* duration of the io.
|
|
*/
|
|
generic_make_request(bio);
|
|
}
|
|
|
|
static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
|
|
{
|
|
return (bio_data_dir(bio) == WRITE) &&
|
|
(bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
|
|
}
|
|
|
|
static void avoid_copy(struct dm_cache_migration *mg)
|
|
{
|
|
atomic_inc(&mg->cache->stats.copies_avoided);
|
|
migration_success_pre_commit(mg);
|
|
}
|
|
|
|
static void issue_copy(struct dm_cache_migration *mg)
|
|
{
|
|
bool avoid;
|
|
struct cache *cache = mg->cache;
|
|
|
|
if (mg->writeback || mg->demote)
|
|
avoid = !is_dirty(cache, mg->cblock) ||
|
|
is_discarded_oblock(cache, mg->old_oblock);
|
|
else {
|
|
struct bio *bio = mg->new_ocell->holder;
|
|
|
|
avoid = is_discarded_oblock(cache, mg->new_oblock);
|
|
|
|
if (!avoid && bio_writes_complete_block(cache, bio)) {
|
|
issue_overwrite(mg, bio);
|
|
return;
|
|
}
|
|
}
|
|
|
|
avoid ? avoid_copy(mg) : issue_copy_real(mg);
|
|
}
|
|
|
|
static void complete_migration(struct dm_cache_migration *mg)
|
|
{
|
|
if (mg->err)
|
|
migration_failure(mg);
|
|
else
|
|
migration_success_pre_commit(mg);
|
|
}
|
|
|
|
static void process_migrations(struct cache *cache, struct list_head *head,
|
|
void (*fn)(struct dm_cache_migration *))
|
|
{
|
|
unsigned long flags;
|
|
struct list_head list;
|
|
struct dm_cache_migration *mg, *tmp;
|
|
|
|
INIT_LIST_HEAD(&list);
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
list_splice_init(head, &list);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
list_for_each_entry_safe(mg, tmp, &list, list)
|
|
fn(mg);
|
|
}
|
|
|
|
static void __queue_quiesced_migration(struct dm_cache_migration *mg)
|
|
{
|
|
list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
|
|
}
|
|
|
|
static void queue_quiesced_migration(struct dm_cache_migration *mg)
|
|
{
|
|
unsigned long flags;
|
|
struct cache *cache = mg->cache;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
__queue_quiesced_migration(mg);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
|
|
{
|
|
unsigned long flags;
|
|
struct dm_cache_migration *mg, *tmp;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
list_for_each_entry_safe(mg, tmp, work, list)
|
|
__queue_quiesced_migration(mg);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void check_for_quiesced_migrations(struct cache *cache,
|
|
struct per_bio_data *pb)
|
|
{
|
|
struct list_head work;
|
|
|
|
if (!pb->all_io_entry)
|
|
return;
|
|
|
|
INIT_LIST_HEAD(&work);
|
|
dm_deferred_entry_dec(pb->all_io_entry, &work);
|
|
|
|
if (!list_empty(&work))
|
|
queue_quiesced_migrations(cache, &work);
|
|
}
|
|
|
|
static void quiesce_migration(struct dm_cache_migration *mg)
|
|
{
|
|
if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
|
|
queue_quiesced_migration(mg);
|
|
}
|
|
|
|
static void promote(struct cache *cache, struct prealloc *structs,
|
|
dm_oblock_t oblock, dm_cblock_t cblock,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
struct dm_cache_migration *mg = prealloc_get_migration(structs);
|
|
|
|
mg->err = false;
|
|
mg->writeback = false;
|
|
mg->demote = false;
|
|
mg->promote = true;
|
|
mg->requeue_holder = true;
|
|
mg->invalidate = false;
|
|
mg->cache = cache;
|
|
mg->new_oblock = oblock;
|
|
mg->cblock = cblock;
|
|
mg->old_ocell = NULL;
|
|
mg->new_ocell = cell;
|
|
mg->start_jiffies = jiffies;
|
|
|
|
inc_nr_migrations(cache);
|
|
quiesce_migration(mg);
|
|
}
|
|
|
|
static void writeback(struct cache *cache, struct prealloc *structs,
|
|
dm_oblock_t oblock, dm_cblock_t cblock,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
struct dm_cache_migration *mg = prealloc_get_migration(structs);
|
|
|
|
mg->err = false;
|
|
mg->writeback = true;
|
|
mg->demote = false;
|
|
mg->promote = false;
|
|
mg->requeue_holder = true;
|
|
mg->invalidate = false;
|
|
mg->cache = cache;
|
|
mg->old_oblock = oblock;
|
|
mg->cblock = cblock;
|
|
mg->old_ocell = cell;
|
|
mg->new_ocell = NULL;
|
|
mg->start_jiffies = jiffies;
|
|
|
|
inc_nr_migrations(cache);
|
|
quiesce_migration(mg);
|
|
}
|
|
|
|
static void demote_then_promote(struct cache *cache, struct prealloc *structs,
|
|
dm_oblock_t old_oblock, dm_oblock_t new_oblock,
|
|
dm_cblock_t cblock,
|
|
struct dm_bio_prison_cell *old_ocell,
|
|
struct dm_bio_prison_cell *new_ocell)
|
|
{
|
|
struct dm_cache_migration *mg = prealloc_get_migration(structs);
|
|
|
|
mg->err = false;
|
|
mg->writeback = false;
|
|
mg->demote = true;
|
|
mg->promote = true;
|
|
mg->requeue_holder = true;
|
|
mg->invalidate = false;
|
|
mg->cache = cache;
|
|
mg->old_oblock = old_oblock;
|
|
mg->new_oblock = new_oblock;
|
|
mg->cblock = cblock;
|
|
mg->old_ocell = old_ocell;
|
|
mg->new_ocell = new_ocell;
|
|
mg->start_jiffies = jiffies;
|
|
|
|
inc_nr_migrations(cache);
|
|
quiesce_migration(mg);
|
|
}
|
|
|
|
/*
|
|
* Invalidate a cache entry. No writeback occurs; any changes in the cache
|
|
* block are thrown away.
|
|
*/
|
|
static void invalidate(struct cache *cache, struct prealloc *structs,
|
|
dm_oblock_t oblock, dm_cblock_t cblock,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
struct dm_cache_migration *mg = prealloc_get_migration(structs);
|
|
|
|
mg->err = false;
|
|
mg->writeback = false;
|
|
mg->demote = true;
|
|
mg->promote = false;
|
|
mg->requeue_holder = true;
|
|
mg->invalidate = true;
|
|
mg->cache = cache;
|
|
mg->old_oblock = oblock;
|
|
mg->cblock = cblock;
|
|
mg->old_ocell = cell;
|
|
mg->new_ocell = NULL;
|
|
mg->start_jiffies = jiffies;
|
|
|
|
inc_nr_migrations(cache);
|
|
quiesce_migration(mg);
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* bio processing
|
|
*--------------------------------------------------------------*/
|
|
static void defer_bio(struct cache *cache, struct bio *bio)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
bio_list_add(&cache->deferred_bios, bio);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
wake_worker(cache);
|
|
}
|
|
|
|
static void process_flush_bio(struct cache *cache, struct bio *bio)
|
|
{
|
|
size_t pb_data_size = get_per_bio_data_size(cache);
|
|
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
|
|
|
|
BUG_ON(bio->bi_iter.bi_size);
|
|
if (!pb->req_nr)
|
|
remap_to_origin(cache, bio);
|
|
else
|
|
remap_to_cache(cache, bio, 0);
|
|
|
|
/*
|
|
* REQ_FLUSH is not directed at any particular block so we don't
|
|
* need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH
|
|
* by dm-core.
|
|
*/
|
|
issue(cache, bio);
|
|
}
|
|
|
|
/*
|
|
* People generally discard large parts of a device, eg, the whole device
|
|
* when formatting. Splitting these large discards up into cache block
|
|
* sized ios and then quiescing (always neccessary for discard) takes too
|
|
* long.
|
|
*
|
|
* We keep it simple, and allow any size of discard to come in, and just
|
|
* mark off blocks on the discard bitset. No passdown occurs!
|
|
*
|
|
* To implement passdown we need to change the bio_prison such that a cell
|
|
* can have a key that spans many blocks.
|
|
*/
|
|
static void process_discard_bio(struct cache *cache, struct bio *bio)
|
|
{
|
|
dm_block_t start_block = dm_sector_div_up(bio->bi_iter.bi_sector,
|
|
cache->sectors_per_block);
|
|
dm_block_t end_block = bio_end_sector(bio);
|
|
dm_block_t b;
|
|
|
|
end_block = block_div(end_block, cache->sectors_per_block);
|
|
|
|
for (b = start_block; b < end_block; b++)
|
|
set_discard(cache, to_oblock(b));
|
|
|
|
bio_endio(bio, 0);
|
|
}
|
|
|
|
static bool spare_migration_bandwidth(struct cache *cache)
|
|
{
|
|
sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *
|
|
cache->sectors_per_block;
|
|
return current_volume < cache->migration_threshold;
|
|
}
|
|
|
|
static void inc_hit_counter(struct cache *cache, struct bio *bio)
|
|
{
|
|
atomic_inc(bio_data_dir(bio) == READ ?
|
|
&cache->stats.read_hit : &cache->stats.write_hit);
|
|
}
|
|
|
|
static void inc_miss_counter(struct cache *cache, struct bio *bio)
|
|
{
|
|
atomic_inc(bio_data_dir(bio) == READ ?
|
|
&cache->stats.read_miss : &cache->stats.write_miss);
|
|
}
|
|
|
|
static void process_bio(struct cache *cache, struct prealloc *structs,
|
|
struct bio *bio)
|
|
{
|
|
int r;
|
|
bool release_cell = true;
|
|
dm_oblock_t block = get_bio_block(cache, bio);
|
|
struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
|
|
struct policy_result lookup_result;
|
|
bool discarded_block = is_discarded_oblock(cache, block);
|
|
bool passthrough = passthrough_mode(&cache->features);
|
|
bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache));
|
|
|
|
/*
|
|
* Check to see if that block is currently migrating.
|
|
*/
|
|
cell_prealloc = prealloc_get_cell(structs);
|
|
r = bio_detain(cache, block, bio, cell_prealloc,
|
|
(cell_free_fn) prealloc_put_cell,
|
|
structs, &new_ocell);
|
|
if (r > 0)
|
|
return;
|
|
|
|
r = policy_map(cache->policy, block, true, can_migrate, discarded_block,
|
|
bio, &lookup_result);
|
|
|
|
if (r == -EWOULDBLOCK)
|
|
/* migration has been denied */
|
|
lookup_result.op = POLICY_MISS;
|
|
|
|
switch (lookup_result.op) {
|
|
case POLICY_HIT:
|
|
if (passthrough) {
|
|
inc_miss_counter(cache, bio);
|
|
|
|
/*
|
|
* Passthrough always maps to the origin,
|
|
* invalidating any cache blocks that are written
|
|
* to.
|
|
*/
|
|
|
|
if (bio_data_dir(bio) == WRITE) {
|
|
atomic_inc(&cache->stats.demotion);
|
|
invalidate(cache, structs, block, lookup_result.cblock, new_ocell);
|
|
release_cell = false;
|
|
|
|
} else {
|
|
/* FIXME: factor out issue_origin() */
|
|
remap_to_origin_clear_discard(cache, bio, block);
|
|
inc_and_issue(cache, bio, new_ocell);
|
|
}
|
|
} else {
|
|
inc_hit_counter(cache, bio);
|
|
|
|
if (bio_data_dir(bio) == WRITE &&
|
|
writethrough_mode(&cache->features) &&
|
|
!is_dirty(cache, lookup_result.cblock)) {
|
|
remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
|
|
inc_and_issue(cache, bio, new_ocell);
|
|
|
|
} else {
|
|
remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
|
|
inc_and_issue(cache, bio, new_ocell);
|
|
}
|
|
}
|
|
|
|
break;
|
|
|
|
case POLICY_MISS:
|
|
inc_miss_counter(cache, bio);
|
|
remap_to_origin_clear_discard(cache, bio, block);
|
|
inc_and_issue(cache, bio, new_ocell);
|
|
break;
|
|
|
|
case POLICY_NEW:
|
|
atomic_inc(&cache->stats.promotion);
|
|
promote(cache, structs, block, lookup_result.cblock, new_ocell);
|
|
release_cell = false;
|
|
break;
|
|
|
|
case POLICY_REPLACE:
|
|
cell_prealloc = prealloc_get_cell(structs);
|
|
r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc,
|
|
(cell_free_fn) prealloc_put_cell,
|
|
structs, &old_ocell);
|
|
if (r > 0) {
|
|
/*
|
|
* We have to be careful to avoid lock inversion of
|
|
* the cells. So we back off, and wait for the
|
|
* old_ocell to become free.
|
|
*/
|
|
policy_force_mapping(cache->policy, block,
|
|
lookup_result.old_oblock);
|
|
atomic_inc(&cache->stats.cache_cell_clash);
|
|
break;
|
|
}
|
|
atomic_inc(&cache->stats.demotion);
|
|
atomic_inc(&cache->stats.promotion);
|
|
|
|
demote_then_promote(cache, structs, lookup_result.old_oblock,
|
|
block, lookup_result.cblock,
|
|
old_ocell, new_ocell);
|
|
release_cell = false;
|
|
break;
|
|
|
|
default:
|
|
DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__,
|
|
(unsigned) lookup_result.op);
|
|
bio_io_error(bio);
|
|
}
|
|
|
|
if (release_cell)
|
|
cell_defer(cache, new_ocell, false);
|
|
}
|
|
|
|
static int need_commit_due_to_time(struct cache *cache)
|
|
{
|
|
return jiffies < cache->last_commit_jiffies ||
|
|
jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
|
|
}
|
|
|
|
static int commit_if_needed(struct cache *cache)
|
|
{
|
|
int r = 0;
|
|
|
|
if ((cache->commit_requested || need_commit_due_to_time(cache)) &&
|
|
dm_cache_changed_this_transaction(cache->cmd)) {
|
|
atomic_inc(&cache->stats.commit_count);
|
|
cache->commit_requested = false;
|
|
r = dm_cache_commit(cache->cmd, false);
|
|
cache->last_commit_jiffies = jiffies;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static void process_deferred_bios(struct cache *cache)
|
|
{
|
|
unsigned long flags;
|
|
struct bio_list bios;
|
|
struct bio *bio;
|
|
struct prealloc structs;
|
|
|
|
memset(&structs, 0, sizeof(structs));
|
|
bio_list_init(&bios);
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
bio_list_merge(&bios, &cache->deferred_bios);
|
|
bio_list_init(&cache->deferred_bios);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
while (!bio_list_empty(&bios)) {
|
|
/*
|
|
* If we've got no free migration structs, and processing
|
|
* this bio might require one, we pause until there are some
|
|
* prepared mappings to process.
|
|
*/
|
|
if (prealloc_data_structs(cache, &structs)) {
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
bio_list_merge(&cache->deferred_bios, &bios);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
break;
|
|
}
|
|
|
|
bio = bio_list_pop(&bios);
|
|
|
|
if (bio->bi_rw & REQ_FLUSH)
|
|
process_flush_bio(cache, bio);
|
|
else if (bio->bi_rw & REQ_DISCARD)
|
|
process_discard_bio(cache, bio);
|
|
else
|
|
process_bio(cache, &structs, bio);
|
|
}
|
|
|
|
prealloc_free_structs(cache, &structs);
|
|
}
|
|
|
|
static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
|
|
{
|
|
unsigned long flags;
|
|
struct bio_list bios;
|
|
struct bio *bio;
|
|
|
|
bio_list_init(&bios);
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
bio_list_merge(&bios, &cache->deferred_flush_bios);
|
|
bio_list_init(&cache->deferred_flush_bios);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
/*
|
|
* These bios have already been through inc_ds()
|
|
*/
|
|
while ((bio = bio_list_pop(&bios)))
|
|
submit_bios ? generic_make_request(bio) : bio_io_error(bio);
|
|
}
|
|
|
|
static void process_deferred_writethrough_bios(struct cache *cache)
|
|
{
|
|
unsigned long flags;
|
|
struct bio_list bios;
|
|
struct bio *bio;
|
|
|
|
bio_list_init(&bios);
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
bio_list_merge(&bios, &cache->deferred_writethrough_bios);
|
|
bio_list_init(&cache->deferred_writethrough_bios);
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
|
|
/*
|
|
* These bios have already been through inc_ds()
|
|
*/
|
|
while ((bio = bio_list_pop(&bios)))
|
|
generic_make_request(bio);
|
|
}
|
|
|
|
static void writeback_some_dirty_blocks(struct cache *cache)
|
|
{
|
|
int r = 0;
|
|
dm_oblock_t oblock;
|
|
dm_cblock_t cblock;
|
|
struct prealloc structs;
|
|
struct dm_bio_prison_cell *old_ocell;
|
|
|
|
memset(&structs, 0, sizeof(structs));
|
|
|
|
while (spare_migration_bandwidth(cache)) {
|
|
if (prealloc_data_structs(cache, &structs))
|
|
break;
|
|
|
|
r = policy_writeback_work(cache->policy, &oblock, &cblock);
|
|
if (r)
|
|
break;
|
|
|
|
r = get_cell(cache, oblock, &structs, &old_ocell);
|
|
if (r) {
|
|
policy_set_dirty(cache->policy, oblock);
|
|
break;
|
|
}
|
|
|
|
writeback(cache, &structs, oblock, cblock, old_ocell);
|
|
}
|
|
|
|
prealloc_free_structs(cache, &structs);
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* Invalidations.
|
|
* Dropping something from the cache *without* writing back.
|
|
*--------------------------------------------------------------*/
|
|
|
|
static void process_invalidation_request(struct cache *cache, struct invalidation_request *req)
|
|
{
|
|
int r = 0;
|
|
uint64_t begin = from_cblock(req->cblocks->begin);
|
|
uint64_t end = from_cblock(req->cblocks->end);
|
|
|
|
while (begin != end) {
|
|
r = policy_remove_cblock(cache->policy, to_cblock(begin));
|
|
if (!r) {
|
|
r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin));
|
|
if (r)
|
|
break;
|
|
|
|
} else if (r == -ENODATA) {
|
|
/* harmless, already unmapped */
|
|
r = 0;
|
|
|
|
} else {
|
|
DMERR("policy_remove_cblock failed");
|
|
break;
|
|
}
|
|
|
|
begin++;
|
|
}
|
|
|
|
cache->commit_requested = true;
|
|
|
|
req->err = r;
|
|
atomic_set(&req->complete, 1);
|
|
|
|
wake_up(&req->result_wait);
|
|
}
|
|
|
|
static void process_invalidation_requests(struct cache *cache)
|
|
{
|
|
struct list_head list;
|
|
struct invalidation_request *req, *tmp;
|
|
|
|
INIT_LIST_HEAD(&list);
|
|
spin_lock(&cache->invalidation_lock);
|
|
list_splice_init(&cache->invalidation_requests, &list);
|
|
spin_unlock(&cache->invalidation_lock);
|
|
|
|
list_for_each_entry_safe (req, tmp, &list, list)
|
|
process_invalidation_request(cache, req);
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* Main worker loop
|
|
*--------------------------------------------------------------*/
|
|
static bool is_quiescing(struct cache *cache)
|
|
{
|
|
return atomic_read(&cache->quiescing);
|
|
}
|
|
|
|
static void ack_quiescing(struct cache *cache)
|
|
{
|
|
if (is_quiescing(cache)) {
|
|
atomic_inc(&cache->quiescing_ack);
|
|
wake_up(&cache->quiescing_wait);
|
|
}
|
|
}
|
|
|
|
static void wait_for_quiescing_ack(struct cache *cache)
|
|
{
|
|
wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack));
|
|
}
|
|
|
|
static void start_quiescing(struct cache *cache)
|
|
{
|
|
atomic_inc(&cache->quiescing);
|
|
wait_for_quiescing_ack(cache);
|
|
}
|
|
|
|
static void stop_quiescing(struct cache *cache)
|
|
{
|
|
atomic_set(&cache->quiescing, 0);
|
|
atomic_set(&cache->quiescing_ack, 0);
|
|
}
|
|
|
|
static void wait_for_migrations(struct cache *cache)
|
|
{
|
|
wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));
|
|
}
|
|
|
|
static void stop_worker(struct cache *cache)
|
|
{
|
|
cancel_delayed_work(&cache->waker);
|
|
flush_workqueue(cache->wq);
|
|
}
|
|
|
|
static void requeue_deferred_io(struct cache *cache)
|
|
{
|
|
struct bio *bio;
|
|
struct bio_list bios;
|
|
|
|
bio_list_init(&bios);
|
|
bio_list_merge(&bios, &cache->deferred_bios);
|
|
bio_list_init(&cache->deferred_bios);
|
|
|
|
while ((bio = bio_list_pop(&bios)))
|
|
bio_endio(bio, DM_ENDIO_REQUEUE);
|
|
}
|
|
|
|
static int more_work(struct cache *cache)
|
|
{
|
|
if (is_quiescing(cache))
|
|
return !list_empty(&cache->quiesced_migrations) ||
|
|
!list_empty(&cache->completed_migrations) ||
|
|
!list_empty(&cache->need_commit_migrations);
|
|
else
|
|
return !bio_list_empty(&cache->deferred_bios) ||
|
|
!bio_list_empty(&cache->deferred_flush_bios) ||
|
|
!bio_list_empty(&cache->deferred_writethrough_bios) ||
|
|
!list_empty(&cache->quiesced_migrations) ||
|
|
!list_empty(&cache->completed_migrations) ||
|
|
!list_empty(&cache->need_commit_migrations) ||
|
|
cache->invalidate;
|
|
}
|
|
|
|
static void do_worker(struct work_struct *ws)
|
|
{
|
|
struct cache *cache = container_of(ws, struct cache, worker);
|
|
|
|
do {
|
|
if (!is_quiescing(cache)) {
|
|
writeback_some_dirty_blocks(cache);
|
|
process_deferred_writethrough_bios(cache);
|
|
process_deferred_bios(cache);
|
|
process_invalidation_requests(cache);
|
|
}
|
|
|
|
process_migrations(cache, &cache->quiesced_migrations, issue_copy);
|
|
process_migrations(cache, &cache->completed_migrations, complete_migration);
|
|
|
|
if (commit_if_needed(cache)) {
|
|
process_deferred_flush_bios(cache, false);
|
|
process_migrations(cache, &cache->need_commit_migrations, migration_failure);
|
|
|
|
/*
|
|
* FIXME: rollback metadata or just go into a
|
|
* failure mode and error everything
|
|
*/
|
|
} else {
|
|
process_deferred_flush_bios(cache, true);
|
|
process_migrations(cache, &cache->need_commit_migrations,
|
|
migration_success_post_commit);
|
|
}
|
|
|
|
ack_quiescing(cache);
|
|
|
|
} while (more_work(cache));
|
|
}
|
|
|
|
/*
|
|
* We want to commit periodically so that not too much
|
|
* unwritten metadata builds up.
|
|
*/
|
|
static void do_waker(struct work_struct *ws)
|
|
{
|
|
struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
|
|
policy_tick(cache->policy);
|
|
wake_worker(cache);
|
|
queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
|
|
}
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
static int is_congested(struct dm_dev *dev, int bdi_bits)
|
|
{
|
|
struct request_queue *q = bdev_get_queue(dev->bdev);
|
|
return bdi_congested(&q->backing_dev_info, bdi_bits);
|
|
}
|
|
|
|
static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
|
|
{
|
|
struct cache *cache = container_of(cb, struct cache, callbacks);
|
|
|
|
return is_congested(cache->origin_dev, bdi_bits) ||
|
|
is_congested(cache->cache_dev, bdi_bits);
|
|
}
|
|
|
|
/*----------------------------------------------------------------
|
|
* Target methods
|
|
*--------------------------------------------------------------*/
|
|
|
|
/*
|
|
* This function gets called on the error paths of the constructor, so we
|
|
* have to cope with a partially initialised struct.
|
|
*/
|
|
static void destroy(struct cache *cache)
|
|
{
|
|
unsigned i;
|
|
|
|
if (cache->next_migration)
|
|
mempool_free(cache->next_migration, cache->migration_pool);
|
|
|
|
if (cache->migration_pool)
|
|
mempool_destroy(cache->migration_pool);
|
|
|
|
if (cache->all_io_ds)
|
|
dm_deferred_set_destroy(cache->all_io_ds);
|
|
|
|
if (cache->prison)
|
|
dm_bio_prison_destroy(cache->prison);
|
|
|
|
if (cache->wq)
|
|
destroy_workqueue(cache->wq);
|
|
|
|
if (cache->dirty_bitset)
|
|
free_bitset(cache->dirty_bitset);
|
|
|
|
if (cache->discard_bitset)
|
|
free_bitset(cache->discard_bitset);
|
|
|
|
if (cache->copier)
|
|
dm_kcopyd_client_destroy(cache->copier);
|
|
|
|
if (cache->cmd)
|
|
dm_cache_metadata_close(cache->cmd);
|
|
|
|
if (cache->metadata_dev)
|
|
dm_put_device(cache->ti, cache->metadata_dev);
|
|
|
|
if (cache->origin_dev)
|
|
dm_put_device(cache->ti, cache->origin_dev);
|
|
|
|
if (cache->cache_dev)
|
|
dm_put_device(cache->ti, cache->cache_dev);
|
|
|
|
if (cache->policy)
|
|
dm_cache_policy_destroy(cache->policy);
|
|
|
|
for (i = 0; i < cache->nr_ctr_args ; i++)
|
|
kfree(cache->ctr_args[i]);
|
|
kfree(cache->ctr_args);
|
|
|
|
kfree(cache);
|
|
}
|
|
|
|
static void cache_dtr(struct dm_target *ti)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
|
|
destroy(cache);
|
|
}
|
|
|
|
static sector_t get_dev_size(struct dm_dev *dev)
|
|
{
|
|
return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
|
|
}
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Construct a cache device mapping.
|
|
*
|
|
* cache <metadata dev> <cache dev> <origin dev> <block size>
|
|
* <#feature args> [<feature arg>]*
|
|
* <policy> <#policy args> [<policy arg>]*
|
|
*
|
|
* metadata dev : fast device holding the persistent metadata
|
|
* cache dev : fast device holding cached data blocks
|
|
* origin dev : slow device holding original data blocks
|
|
* block size : cache unit size in sectors
|
|
*
|
|
* #feature args : number of feature arguments passed
|
|
* feature args : writethrough. (The default is writeback.)
|
|
*
|
|
* policy : the replacement policy to use
|
|
* #policy args : an even number of policy arguments corresponding
|
|
* to key/value pairs passed to the policy
|
|
* policy args : key/value pairs passed to the policy
|
|
* E.g. 'sequential_threshold 1024'
|
|
* See cache-policies.txt for details.
|
|
*
|
|
* Optional feature arguments are:
|
|
* writethrough : write through caching that prohibits cache block
|
|
* content from being different from origin block content.
|
|
* Without this argument, the default behaviour is to write
|
|
* back cache block contents later for performance reasons,
|
|
* so they may differ from the corresponding origin blocks.
|
|
*/
|
|
struct cache_args {
|
|
struct dm_target *ti;
|
|
|
|
struct dm_dev *metadata_dev;
|
|
|
|
struct dm_dev *cache_dev;
|
|
sector_t cache_sectors;
|
|
|
|
struct dm_dev *origin_dev;
|
|
sector_t origin_sectors;
|
|
|
|
uint32_t block_size;
|
|
|
|
const char *policy_name;
|
|
int policy_argc;
|
|
const char **policy_argv;
|
|
|
|
struct cache_features features;
|
|
};
|
|
|
|
static void destroy_cache_args(struct cache_args *ca)
|
|
{
|
|
if (ca->metadata_dev)
|
|
dm_put_device(ca->ti, ca->metadata_dev);
|
|
|
|
if (ca->cache_dev)
|
|
dm_put_device(ca->ti, ca->cache_dev);
|
|
|
|
if (ca->origin_dev)
|
|
dm_put_device(ca->ti, ca->origin_dev);
|
|
|
|
kfree(ca);
|
|
}
|
|
|
|
static bool at_least_one_arg(struct dm_arg_set *as, char **error)
|
|
{
|
|
if (!as->argc) {
|
|
*error = "Insufficient args";
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
|
|
char **error)
|
|
{
|
|
int r;
|
|
sector_t metadata_dev_size;
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
if (!at_least_one_arg(as, error))
|
|
return -EINVAL;
|
|
|
|
r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
|
|
&ca->metadata_dev);
|
|
if (r) {
|
|
*error = "Error opening metadata device";
|
|
return r;
|
|
}
|
|
|
|
metadata_dev_size = get_dev_size(ca->metadata_dev);
|
|
if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
|
|
DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
|
|
bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
|
|
char **error)
|
|
{
|
|
int r;
|
|
|
|
if (!at_least_one_arg(as, error))
|
|
return -EINVAL;
|
|
|
|
r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
|
|
&ca->cache_dev);
|
|
if (r) {
|
|
*error = "Error opening cache device";
|
|
return r;
|
|
}
|
|
ca->cache_sectors = get_dev_size(ca->cache_dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
|
|
char **error)
|
|
{
|
|
int r;
|
|
|
|
if (!at_least_one_arg(as, error))
|
|
return -EINVAL;
|
|
|
|
r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
|
|
&ca->origin_dev);
|
|
if (r) {
|
|
*error = "Error opening origin device";
|
|
return r;
|
|
}
|
|
|
|
ca->origin_sectors = get_dev_size(ca->origin_dev);
|
|
if (ca->ti->len > ca->origin_sectors) {
|
|
*error = "Device size larger than cached device";
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
|
|
char **error)
|
|
{
|
|
unsigned long block_size;
|
|
|
|
if (!at_least_one_arg(as, error))
|
|
return -EINVAL;
|
|
|
|
if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size ||
|
|
block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
|
|
block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
|
|
block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
|
|
*error = "Invalid data block size";
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (block_size > ca->cache_sectors) {
|
|
*error = "Data block size is larger than the cache device";
|
|
return -EINVAL;
|
|
}
|
|
|
|
ca->block_size = block_size;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void init_features(struct cache_features *cf)
|
|
{
|
|
cf->mode = CM_WRITE;
|
|
cf->io_mode = CM_IO_WRITEBACK;
|
|
}
|
|
|
|
static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
|
|
char **error)
|
|
{
|
|
static struct dm_arg _args[] = {
|
|
{0, 1, "Invalid number of cache feature arguments"},
|
|
};
|
|
|
|
int r;
|
|
unsigned argc;
|
|
const char *arg;
|
|
struct cache_features *cf = &ca->features;
|
|
|
|
init_features(cf);
|
|
|
|
r = dm_read_arg_group(_args, as, &argc, error);
|
|
if (r)
|
|
return -EINVAL;
|
|
|
|
while (argc--) {
|
|
arg = dm_shift_arg(as);
|
|
|
|
if (!strcasecmp(arg, "writeback"))
|
|
cf->io_mode = CM_IO_WRITEBACK;
|
|
|
|
else if (!strcasecmp(arg, "writethrough"))
|
|
cf->io_mode = CM_IO_WRITETHROUGH;
|
|
|
|
else if (!strcasecmp(arg, "passthrough"))
|
|
cf->io_mode = CM_IO_PASSTHROUGH;
|
|
|
|
else {
|
|
*error = "Unrecognised cache feature requested";
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
|
|
char **error)
|
|
{
|
|
static struct dm_arg _args[] = {
|
|
{0, 1024, "Invalid number of policy arguments"},
|
|
};
|
|
|
|
int r;
|
|
|
|
if (!at_least_one_arg(as, error))
|
|
return -EINVAL;
|
|
|
|
ca->policy_name = dm_shift_arg(as);
|
|
|
|
r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
|
|
if (r)
|
|
return -EINVAL;
|
|
|
|
ca->policy_argv = (const char **)as->argv;
|
|
dm_consume_args(as, ca->policy_argc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
|
|
char **error)
|
|
{
|
|
int r;
|
|
struct dm_arg_set as;
|
|
|
|
as.argc = argc;
|
|
as.argv = argv;
|
|
|
|
r = parse_metadata_dev(ca, &as, error);
|
|
if (r)
|
|
return r;
|
|
|
|
r = parse_cache_dev(ca, &as, error);
|
|
if (r)
|
|
return r;
|
|
|
|
r = parse_origin_dev(ca, &as, error);
|
|
if (r)
|
|
return r;
|
|
|
|
r = parse_block_size(ca, &as, error);
|
|
if (r)
|
|
return r;
|
|
|
|
r = parse_features(ca, &as, error);
|
|
if (r)
|
|
return r;
|
|
|
|
r = parse_policy(ca, &as, error);
|
|
if (r)
|
|
return r;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
static struct kmem_cache *migration_cache;
|
|
|
|
#define NOT_CORE_OPTION 1
|
|
|
|
static int process_config_option(struct cache *cache, const char *key, const char *value)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
if (!strcasecmp(key, "migration_threshold")) {
|
|
if (kstrtoul(value, 10, &tmp))
|
|
return -EINVAL;
|
|
|
|
cache->migration_threshold = tmp;
|
|
return 0;
|
|
}
|
|
|
|
return NOT_CORE_OPTION;
|
|
}
|
|
|
|
static int set_config_value(struct cache *cache, const char *key, const char *value)
|
|
{
|
|
int r = process_config_option(cache, key, value);
|
|
|
|
if (r == NOT_CORE_OPTION)
|
|
r = policy_set_config_value(cache->policy, key, value);
|
|
|
|
if (r)
|
|
DMWARN("bad config value for %s: %s", key, value);
|
|
|
|
return r;
|
|
}
|
|
|
|
static int set_config_values(struct cache *cache, int argc, const char **argv)
|
|
{
|
|
int r = 0;
|
|
|
|
if (argc & 1) {
|
|
DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
|
|
return -EINVAL;
|
|
}
|
|
|
|
while (argc) {
|
|
r = set_config_value(cache, argv[0], argv[1]);
|
|
if (r)
|
|
break;
|
|
|
|
argc -= 2;
|
|
argv += 2;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int create_cache_policy(struct cache *cache, struct cache_args *ca,
|
|
char **error)
|
|
{
|
|
struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name,
|
|
cache->cache_size,
|
|
cache->origin_sectors,
|
|
cache->sectors_per_block);
|
|
if (IS_ERR(p)) {
|
|
*error = "Error creating cache's policy";
|
|
return PTR_ERR(p);
|
|
}
|
|
cache->policy = p;
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define DEFAULT_MIGRATION_THRESHOLD 2048
|
|
|
|
static int cache_create(struct cache_args *ca, struct cache **result)
|
|
{
|
|
int r = 0;
|
|
char **error = &ca->ti->error;
|
|
struct cache *cache;
|
|
struct dm_target *ti = ca->ti;
|
|
dm_block_t origin_blocks;
|
|
struct dm_cache_metadata *cmd;
|
|
bool may_format = ca->features.mode == CM_WRITE;
|
|
|
|
cache = kzalloc(sizeof(*cache), GFP_KERNEL);
|
|
if (!cache)
|
|
return -ENOMEM;
|
|
|
|
cache->ti = ca->ti;
|
|
ti->private = cache;
|
|
ti->num_flush_bios = 2;
|
|
ti->flush_supported = true;
|
|
|
|
ti->num_discard_bios = 1;
|
|
ti->discards_supported = true;
|
|
ti->discard_zeroes_data_unsupported = true;
|
|
/* Discard bios must be split on a block boundary */
|
|
ti->split_discard_bios = true;
|
|
|
|
cache->features = ca->features;
|
|
ti->per_bio_data_size = get_per_bio_data_size(cache);
|
|
|
|
cache->callbacks.congested_fn = cache_is_congested;
|
|
dm_table_add_target_callbacks(ti->table, &cache->callbacks);
|
|
|
|
cache->metadata_dev = ca->metadata_dev;
|
|
cache->origin_dev = ca->origin_dev;
|
|
cache->cache_dev = ca->cache_dev;
|
|
|
|
ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
|
|
|
|
/* FIXME: factor out this whole section */
|
|
origin_blocks = cache->origin_sectors = ca->origin_sectors;
|
|
origin_blocks = block_div(origin_blocks, ca->block_size);
|
|
cache->origin_blocks = to_oblock(origin_blocks);
|
|
|
|
cache->sectors_per_block = ca->block_size;
|
|
if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
|
|
r = -EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
if (ca->block_size & (ca->block_size - 1)) {
|
|
dm_block_t cache_size = ca->cache_sectors;
|
|
|
|
cache->sectors_per_block_shift = -1;
|
|
cache_size = block_div(cache_size, ca->block_size);
|
|
cache->cache_size = to_cblock(cache_size);
|
|
} else {
|
|
cache->sectors_per_block_shift = __ffs(ca->block_size);
|
|
cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift);
|
|
}
|
|
|
|
r = create_cache_policy(cache, ca, error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
cache->policy_nr_args = ca->policy_argc;
|
|
cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
|
|
|
|
r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
|
|
if (r) {
|
|
*error = "Error setting cache policy's config values";
|
|
goto bad;
|
|
}
|
|
|
|
cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
|
|
ca->block_size, may_format,
|
|
dm_cache_policy_get_hint_size(cache->policy));
|
|
if (IS_ERR(cmd)) {
|
|
*error = "Error creating metadata object";
|
|
r = PTR_ERR(cmd);
|
|
goto bad;
|
|
}
|
|
cache->cmd = cmd;
|
|
|
|
if (passthrough_mode(&cache->features)) {
|
|
bool all_clean;
|
|
|
|
r = dm_cache_metadata_all_clean(cache->cmd, &all_clean);
|
|
if (r) {
|
|
*error = "dm_cache_metadata_all_clean() failed";
|
|
goto bad;
|
|
}
|
|
|
|
if (!all_clean) {
|
|
*error = "Cannot enter passthrough mode unless all blocks are clean";
|
|
r = -EINVAL;
|
|
goto bad;
|
|
}
|
|
}
|
|
|
|
spin_lock_init(&cache->lock);
|
|
bio_list_init(&cache->deferred_bios);
|
|
bio_list_init(&cache->deferred_flush_bios);
|
|
bio_list_init(&cache->deferred_writethrough_bios);
|
|
INIT_LIST_HEAD(&cache->quiesced_migrations);
|
|
INIT_LIST_HEAD(&cache->completed_migrations);
|
|
INIT_LIST_HEAD(&cache->need_commit_migrations);
|
|
atomic_set(&cache->nr_migrations, 0);
|
|
init_waitqueue_head(&cache->migration_wait);
|
|
|
|
init_waitqueue_head(&cache->quiescing_wait);
|
|
atomic_set(&cache->quiescing, 0);
|
|
atomic_set(&cache->quiescing_ack, 0);
|
|
|
|
r = -ENOMEM;
|
|
atomic_set(&cache->nr_dirty, 0);
|
|
cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
|
|
if (!cache->dirty_bitset) {
|
|
*error = "could not allocate dirty bitset";
|
|
goto bad;
|
|
}
|
|
clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
|
|
|
|
cache->discard_nr_blocks = cache->origin_blocks;
|
|
cache->discard_bitset = alloc_bitset(from_oblock(cache->discard_nr_blocks));
|
|
if (!cache->discard_bitset) {
|
|
*error = "could not allocate discard bitset";
|
|
goto bad;
|
|
}
|
|
clear_bitset(cache->discard_bitset, from_oblock(cache->discard_nr_blocks));
|
|
|
|
cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
|
|
if (IS_ERR(cache->copier)) {
|
|
*error = "could not create kcopyd client";
|
|
r = PTR_ERR(cache->copier);
|
|
goto bad;
|
|
}
|
|
|
|
cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
|
|
if (!cache->wq) {
|
|
*error = "could not create workqueue for metadata object";
|
|
goto bad;
|
|
}
|
|
INIT_WORK(&cache->worker, do_worker);
|
|
INIT_DELAYED_WORK(&cache->waker, do_waker);
|
|
cache->last_commit_jiffies = jiffies;
|
|
|
|
cache->prison = dm_bio_prison_create(PRISON_CELLS);
|
|
if (!cache->prison) {
|
|
*error = "could not create bio prison";
|
|
goto bad;
|
|
}
|
|
|
|
cache->all_io_ds = dm_deferred_set_create();
|
|
if (!cache->all_io_ds) {
|
|
*error = "could not create all_io deferred set";
|
|
goto bad;
|
|
}
|
|
|
|
cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
|
|
migration_cache);
|
|
if (!cache->migration_pool) {
|
|
*error = "Error creating cache's migration mempool";
|
|
goto bad;
|
|
}
|
|
|
|
cache->next_migration = NULL;
|
|
|
|
cache->need_tick_bio = true;
|
|
cache->sized = false;
|
|
cache->invalidate = false;
|
|
cache->commit_requested = false;
|
|
cache->loaded_mappings = false;
|
|
cache->loaded_discards = false;
|
|
|
|
load_stats(cache);
|
|
|
|
atomic_set(&cache->stats.demotion, 0);
|
|
atomic_set(&cache->stats.promotion, 0);
|
|
atomic_set(&cache->stats.copies_avoided, 0);
|
|
atomic_set(&cache->stats.cache_cell_clash, 0);
|
|
atomic_set(&cache->stats.commit_count, 0);
|
|
atomic_set(&cache->stats.discard_count, 0);
|
|
|
|
spin_lock_init(&cache->invalidation_lock);
|
|
INIT_LIST_HEAD(&cache->invalidation_requests);
|
|
|
|
*result = cache;
|
|
return 0;
|
|
|
|
bad:
|
|
destroy(cache);
|
|
return r;
|
|
}
|
|
|
|
static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
|
|
{
|
|
unsigned i;
|
|
const char **copy;
|
|
|
|
copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
|
|
if (!copy)
|
|
return -ENOMEM;
|
|
for (i = 0; i < argc; i++) {
|
|
copy[i] = kstrdup(argv[i], GFP_KERNEL);
|
|
if (!copy[i]) {
|
|
while (i--)
|
|
kfree(copy[i]);
|
|
kfree(copy);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
cache->nr_ctr_args = argc;
|
|
cache->ctr_args = copy;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
|
|
{
|
|
int r = -EINVAL;
|
|
struct cache_args *ca;
|
|
struct cache *cache = NULL;
|
|
|
|
ca = kzalloc(sizeof(*ca), GFP_KERNEL);
|
|
if (!ca) {
|
|
ti->error = "Error allocating memory for cache";
|
|
return -ENOMEM;
|
|
}
|
|
ca->ti = ti;
|
|
|
|
r = parse_cache_args(ca, argc, argv, &ti->error);
|
|
if (r)
|
|
goto out;
|
|
|
|
r = cache_create(ca, &cache);
|
|
if (r)
|
|
goto out;
|
|
|
|
r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
|
|
if (r) {
|
|
destroy(cache);
|
|
goto out;
|
|
}
|
|
|
|
ti->private = cache;
|
|
|
|
out:
|
|
destroy_cache_args(ca);
|
|
return r;
|
|
}
|
|
|
|
static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell **cell)
|
|
{
|
|
int r;
|
|
dm_oblock_t block = get_bio_block(cache, bio);
|
|
size_t pb_data_size = get_per_bio_data_size(cache);
|
|
bool can_migrate = false;
|
|
bool discarded_block;
|
|
struct policy_result lookup_result;
|
|
struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
|
|
|
|
if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
|
|
/*
|
|
* This can only occur if the io goes to a partial block at
|
|
* the end of the origin device. We don't cache these.
|
|
* Just remap to the origin and carry on.
|
|
*/
|
|
remap_to_origin(cache, bio);
|
|
return DM_MAPIO_REMAPPED;
|
|
}
|
|
|
|
if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
|
|
defer_bio(cache, bio);
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
/*
|
|
* Check to see if that block is currently migrating.
|
|
*/
|
|
*cell = alloc_prison_cell(cache);
|
|
if (!*cell) {
|
|
defer_bio(cache, bio);
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
r = bio_detain(cache, block, bio, *cell,
|
|
(cell_free_fn) free_prison_cell,
|
|
cache, cell);
|
|
if (r) {
|
|
if (r < 0)
|
|
defer_bio(cache, bio);
|
|
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
discarded_block = is_discarded_oblock(cache, block);
|
|
|
|
r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
|
|
bio, &lookup_result);
|
|
if (r == -EWOULDBLOCK) {
|
|
cell_defer(cache, *cell, true);
|
|
return DM_MAPIO_SUBMITTED;
|
|
|
|
} else if (r) {
|
|
DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
|
|
cell_defer(cache, *cell, false);
|
|
bio_io_error(bio);
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
r = DM_MAPIO_REMAPPED;
|
|
switch (lookup_result.op) {
|
|
case POLICY_HIT:
|
|
if (passthrough_mode(&cache->features)) {
|
|
if (bio_data_dir(bio) == WRITE) {
|
|
/*
|
|
* We need to invalidate this block, so
|
|
* defer for the worker thread.
|
|
*/
|
|
cell_defer(cache, *cell, true);
|
|
r = DM_MAPIO_SUBMITTED;
|
|
|
|
} else {
|
|
inc_miss_counter(cache, bio);
|
|
remap_to_origin_clear_discard(cache, bio, block);
|
|
}
|
|
|
|
} else {
|
|
inc_hit_counter(cache, bio);
|
|
if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
|
|
!is_dirty(cache, lookup_result.cblock))
|
|
remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
|
|
else
|
|
remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
|
|
}
|
|
break;
|
|
|
|
case POLICY_MISS:
|
|
inc_miss_counter(cache, bio);
|
|
if (pb->req_nr != 0) {
|
|
/*
|
|
* This is a duplicate writethrough io that is no
|
|
* longer needed because the block has been demoted.
|
|
*/
|
|
bio_endio(bio, 0);
|
|
cell_defer(cache, *cell, false);
|
|
r = DM_MAPIO_SUBMITTED;
|
|
|
|
} else
|
|
remap_to_origin_clear_discard(cache, bio, block);
|
|
|
|
break;
|
|
|
|
default:
|
|
DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
|
|
(unsigned) lookup_result.op);
|
|
cell_defer(cache, *cell, false);
|
|
bio_io_error(bio);
|
|
r = DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int cache_map(struct dm_target *ti, struct bio *bio)
|
|
{
|
|
int r;
|
|
struct dm_bio_prison_cell *cell;
|
|
struct cache *cache = ti->private;
|
|
|
|
r = __cache_map(cache, bio, &cell);
|
|
if (r == DM_MAPIO_REMAPPED) {
|
|
inc_ds(cache, bio, cell);
|
|
cell_defer(cache, cell, false);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
unsigned long flags;
|
|
size_t pb_data_size = get_per_bio_data_size(cache);
|
|
struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
|
|
|
|
if (pb->tick) {
|
|
policy_tick(cache->policy);
|
|
|
|
spin_lock_irqsave(&cache->lock, flags);
|
|
cache->need_tick_bio = true;
|
|
spin_unlock_irqrestore(&cache->lock, flags);
|
|
}
|
|
|
|
check_for_quiesced_migrations(cache, pb);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int write_dirty_bitset(struct cache *cache)
|
|
{
|
|
unsigned i, r;
|
|
|
|
for (i = 0; i < from_cblock(cache->cache_size); i++) {
|
|
r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
|
|
is_dirty(cache, to_cblock(i)));
|
|
if (r)
|
|
return r;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int write_discard_bitset(struct cache *cache)
|
|
{
|
|
unsigned i, r;
|
|
|
|
r = dm_cache_discard_bitset_resize(cache->cmd, cache->sectors_per_block,
|
|
cache->origin_blocks);
|
|
if (r) {
|
|
DMERR("could not resize on-disk discard bitset");
|
|
return r;
|
|
}
|
|
|
|
for (i = 0; i < from_oblock(cache->discard_nr_blocks); i++) {
|
|
r = dm_cache_set_discard(cache->cmd, to_oblock(i),
|
|
is_discarded(cache, to_oblock(i)));
|
|
if (r)
|
|
return r;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* returns true on success
|
|
*/
|
|
static bool sync_metadata(struct cache *cache)
|
|
{
|
|
int r1, r2, r3, r4;
|
|
|
|
r1 = write_dirty_bitset(cache);
|
|
if (r1)
|
|
DMERR("could not write dirty bitset");
|
|
|
|
r2 = write_discard_bitset(cache);
|
|
if (r2)
|
|
DMERR("could not write discard bitset");
|
|
|
|
save_stats(cache);
|
|
|
|
r3 = dm_cache_write_hints(cache->cmd, cache->policy);
|
|
if (r3)
|
|
DMERR("could not write hints");
|
|
|
|
/*
|
|
* If writing the above metadata failed, we still commit, but don't
|
|
* set the clean shutdown flag. This will effectively force every
|
|
* dirty bit to be set on reload.
|
|
*/
|
|
r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3);
|
|
if (r4)
|
|
DMERR("could not write cache metadata. Data loss may occur.");
|
|
|
|
return !r1 && !r2 && !r3 && !r4;
|
|
}
|
|
|
|
static void cache_postsuspend(struct dm_target *ti)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
|
|
start_quiescing(cache);
|
|
wait_for_migrations(cache);
|
|
stop_worker(cache);
|
|
requeue_deferred_io(cache);
|
|
stop_quiescing(cache);
|
|
|
|
(void) sync_metadata(cache);
|
|
}
|
|
|
|
static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
|
|
bool dirty, uint32_t hint, bool hint_valid)
|
|
{
|
|
int r;
|
|
struct cache *cache = context;
|
|
|
|
r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
|
|
if (r)
|
|
return r;
|
|
|
|
if (dirty)
|
|
set_dirty(cache, oblock, cblock);
|
|
else
|
|
clear_dirty(cache, oblock, cblock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int load_discard(void *context, sector_t discard_block_size,
|
|
dm_oblock_t oblock, bool discard)
|
|
{
|
|
struct cache *cache = context;
|
|
|
|
if (discard)
|
|
set_discard(cache, oblock);
|
|
else
|
|
clear_discard(cache, oblock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static dm_cblock_t get_cache_dev_size(struct cache *cache)
|
|
{
|
|
sector_t size = get_dev_size(cache->cache_dev);
|
|
(void) sector_div(size, cache->sectors_per_block);
|
|
return to_cblock(size);
|
|
}
|
|
|
|
static bool can_resize(struct cache *cache, dm_cblock_t new_size)
|
|
{
|
|
if (from_cblock(new_size) > from_cblock(cache->cache_size))
|
|
return true;
|
|
|
|
/*
|
|
* We can't drop a dirty block when shrinking the cache.
|
|
*/
|
|
while (from_cblock(new_size) < from_cblock(cache->cache_size)) {
|
|
new_size = to_cblock(from_cblock(new_size) + 1);
|
|
if (is_dirty(cache, new_size)) {
|
|
DMERR("unable to shrink cache; cache block %llu is dirty",
|
|
(unsigned long long) from_cblock(new_size));
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
|
|
{
|
|
int r;
|
|
|
|
r = dm_cache_resize(cache->cmd, new_size);
|
|
if (r) {
|
|
DMERR("could not resize cache metadata");
|
|
return r;
|
|
}
|
|
|
|
cache->cache_size = new_size;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cache_preresume(struct dm_target *ti)
|
|
{
|
|
int r = 0;
|
|
struct cache *cache = ti->private;
|
|
dm_cblock_t csize = get_cache_dev_size(cache);
|
|
|
|
/*
|
|
* Check to see if the cache has resized.
|
|
*/
|
|
if (!cache->sized) {
|
|
r = resize_cache_dev(cache, csize);
|
|
if (r)
|
|
return r;
|
|
|
|
cache->sized = true;
|
|
|
|
} else if (csize != cache->cache_size) {
|
|
if (!can_resize(cache, csize))
|
|
return -EINVAL;
|
|
|
|
r = resize_cache_dev(cache, csize);
|
|
if (r)
|
|
return r;
|
|
}
|
|
|
|
if (!cache->loaded_mappings) {
|
|
r = dm_cache_load_mappings(cache->cmd, cache->policy,
|
|
load_mapping, cache);
|
|
if (r) {
|
|
DMERR("could not load cache mappings");
|
|
return r;
|
|
}
|
|
|
|
cache->loaded_mappings = true;
|
|
}
|
|
|
|
if (!cache->loaded_discards) {
|
|
r = dm_cache_load_discards(cache->cmd, load_discard, cache);
|
|
if (r) {
|
|
DMERR("could not load origin discards");
|
|
return r;
|
|
}
|
|
|
|
cache->loaded_discards = true;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static void cache_resume(struct dm_target *ti)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
|
|
cache->need_tick_bio = true;
|
|
do_waker(&cache->waker.work);
|
|
}
|
|
|
|
/*
|
|
* Status format:
|
|
*
|
|
* <metadata block size> <#used metadata blocks>/<#total metadata blocks>
|
|
* <cache block size> <#used cache blocks>/<#total cache blocks>
|
|
* <#read hits> <#read misses> <#write hits> <#write misses>
|
|
* <#demotions> <#promotions> <#dirty>
|
|
* <#features> <features>*
|
|
* <#core args> <core args>
|
|
* <policy name> <#policy args> <policy args>*
|
|
*/
|
|
static void cache_status(struct dm_target *ti, status_type_t type,
|
|
unsigned status_flags, char *result, unsigned maxlen)
|
|
{
|
|
int r = 0;
|
|
unsigned i;
|
|
ssize_t sz = 0;
|
|
dm_block_t nr_free_blocks_metadata = 0;
|
|
dm_block_t nr_blocks_metadata = 0;
|
|
char buf[BDEVNAME_SIZE];
|
|
struct cache *cache = ti->private;
|
|
dm_cblock_t residency;
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
/* Commit to ensure statistics aren't out-of-date */
|
|
if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) {
|
|
r = dm_cache_commit(cache->cmd, false);
|
|
if (r)
|
|
DMERR("could not commit metadata for accurate status");
|
|
}
|
|
|
|
r = dm_cache_get_free_metadata_block_count(cache->cmd,
|
|
&nr_free_blocks_metadata);
|
|
if (r) {
|
|
DMERR("could not get metadata free block count");
|
|
goto err;
|
|
}
|
|
|
|
r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
|
|
if (r) {
|
|
DMERR("could not get metadata device size");
|
|
goto err;
|
|
}
|
|
|
|
residency = policy_residency(cache->policy);
|
|
|
|
DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ",
|
|
(unsigned)DM_CACHE_METADATA_BLOCK_SIZE,
|
|
(unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
|
|
(unsigned long long)nr_blocks_metadata,
|
|
cache->sectors_per_block,
|
|
(unsigned long long) from_cblock(residency),
|
|
(unsigned long long) from_cblock(cache->cache_size),
|
|
(unsigned) atomic_read(&cache->stats.read_hit),
|
|
(unsigned) atomic_read(&cache->stats.read_miss),
|
|
(unsigned) atomic_read(&cache->stats.write_hit),
|
|
(unsigned) atomic_read(&cache->stats.write_miss),
|
|
(unsigned) atomic_read(&cache->stats.demotion),
|
|
(unsigned) atomic_read(&cache->stats.promotion),
|
|
(unsigned long) atomic_read(&cache->nr_dirty));
|
|
|
|
if (writethrough_mode(&cache->features))
|
|
DMEMIT("1 writethrough ");
|
|
|
|
else if (passthrough_mode(&cache->features))
|
|
DMEMIT("1 passthrough ");
|
|
|
|
else if (writeback_mode(&cache->features))
|
|
DMEMIT("1 writeback ");
|
|
|
|
else {
|
|
DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode);
|
|
goto err;
|
|
}
|
|
|
|
DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
|
|
|
|
DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
|
|
if (sz < maxlen) {
|
|
r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
|
|
if (r)
|
|
DMERR("policy_emit_config_values returned %d", r);
|
|
}
|
|
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
|
|
DMEMIT("%s ", buf);
|
|
format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
|
|
DMEMIT("%s ", buf);
|
|
format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
|
|
DMEMIT("%s", buf);
|
|
|
|
for (i = 0; i < cache->nr_ctr_args - 1; i++)
|
|
DMEMIT(" %s", cache->ctr_args[i]);
|
|
if (cache->nr_ctr_args)
|
|
DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
|
|
}
|
|
|
|
return;
|
|
|
|
err:
|
|
DMEMIT("Error");
|
|
}
|
|
|
|
/*
|
|
* A cache block range can take two forms:
|
|
*
|
|
* i) A single cblock, eg. '3456'
|
|
* ii) A begin and end cblock with dots between, eg. 123-234
|
|
*/
|
|
static int parse_cblock_range(struct cache *cache, const char *str,
|
|
struct cblock_range *result)
|
|
{
|
|
char dummy;
|
|
uint64_t b, e;
|
|
int r;
|
|
|
|
/*
|
|
* Try and parse form (ii) first.
|
|
*/
|
|
r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
if (r == 2) {
|
|
result->begin = to_cblock(b);
|
|
result->end = to_cblock(e);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* That didn't work, try form (i).
|
|
*/
|
|
r = sscanf(str, "%llu%c", &b, &dummy);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
if (r == 1) {
|
|
result->begin = to_cblock(b);
|
|
result->end = to_cblock(from_cblock(result->begin) + 1u);
|
|
return 0;
|
|
}
|
|
|
|
DMERR("invalid cblock range '%s'", str);
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int validate_cblock_range(struct cache *cache, struct cblock_range *range)
|
|
{
|
|
uint64_t b = from_cblock(range->begin);
|
|
uint64_t e = from_cblock(range->end);
|
|
uint64_t n = from_cblock(cache->cache_size);
|
|
|
|
if (b >= n) {
|
|
DMERR("begin cblock out of range: %llu >= %llu", b, n);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (e > n) {
|
|
DMERR("end cblock out of range: %llu > %llu", e, n);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (b >= e) {
|
|
DMERR("invalid cblock range: %llu >= %llu", b, e);
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int request_invalidation(struct cache *cache, struct cblock_range *range)
|
|
{
|
|
struct invalidation_request req;
|
|
|
|
INIT_LIST_HEAD(&req.list);
|
|
req.cblocks = range;
|
|
atomic_set(&req.complete, 0);
|
|
req.err = 0;
|
|
init_waitqueue_head(&req.result_wait);
|
|
|
|
spin_lock(&cache->invalidation_lock);
|
|
list_add(&req.list, &cache->invalidation_requests);
|
|
spin_unlock(&cache->invalidation_lock);
|
|
wake_worker(cache);
|
|
|
|
wait_event(req.result_wait, atomic_read(&req.complete));
|
|
return req.err;
|
|
}
|
|
|
|
static int process_invalidate_cblocks_message(struct cache *cache, unsigned count,
|
|
const char **cblock_ranges)
|
|
{
|
|
int r = 0;
|
|
unsigned i;
|
|
struct cblock_range range;
|
|
|
|
if (!passthrough_mode(&cache->features)) {
|
|
DMERR("cache has to be in passthrough mode for invalidation");
|
|
return -EPERM;
|
|
}
|
|
|
|
for (i = 0; i < count; i++) {
|
|
r = parse_cblock_range(cache, cblock_ranges[i], &range);
|
|
if (r)
|
|
break;
|
|
|
|
r = validate_cblock_range(cache, &range);
|
|
if (r)
|
|
break;
|
|
|
|
/*
|
|
* Pass begin and end origin blocks to the worker and wake it.
|
|
*/
|
|
r = request_invalidation(cache, &range);
|
|
if (r)
|
|
break;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Supports
|
|
* "<key> <value>"
|
|
* and
|
|
* "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
|
|
*
|
|
* The key migration_threshold is supported by the cache target core.
|
|
*/
|
|
static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
|
|
if (!argc)
|
|
return -EINVAL;
|
|
|
|
if (!strcasecmp(argv[0], "invalidate_cblocks"))
|
|
return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);
|
|
|
|
if (argc != 2)
|
|
return -EINVAL;
|
|
|
|
return set_config_value(cache, argv[0], argv[1]);
|
|
}
|
|
|
|
static int cache_iterate_devices(struct dm_target *ti,
|
|
iterate_devices_callout_fn fn, void *data)
|
|
{
|
|
int r = 0;
|
|
struct cache *cache = ti->private;
|
|
|
|
r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
|
|
if (!r)
|
|
r = fn(ti, cache->origin_dev, 0, ti->len, data);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* We assume I/O is going to the origin (which is the volume
|
|
* more likely to have restrictions e.g. by being striped).
|
|
* (Looking up the exact location of the data would be expensive
|
|
* and could always be out of date by the time the bio is submitted.)
|
|
*/
|
|
static int cache_bvec_merge(struct dm_target *ti,
|
|
struct bvec_merge_data *bvm,
|
|
struct bio_vec *biovec, int max_size)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
|
|
|
|
if (!q->merge_bvec_fn)
|
|
return max_size;
|
|
|
|
bvm->bi_bdev = cache->origin_dev->bdev;
|
|
return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
|
|
}
|
|
|
|
static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
|
|
{
|
|
/*
|
|
* FIXME: these limits may be incompatible with the cache device
|
|
*/
|
|
limits->max_discard_sectors = cache->sectors_per_block;
|
|
limits->discard_granularity = cache->sectors_per_block << SECTOR_SHIFT;
|
|
}
|
|
|
|
static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
|
|
{
|
|
struct cache *cache = ti->private;
|
|
uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
|
|
|
|
/*
|
|
* If the system-determined stacked limits are compatible with the
|
|
* cache's blocksize (io_opt is a factor) do not override them.
|
|
*/
|
|
if (io_opt_sectors < cache->sectors_per_block ||
|
|
do_div(io_opt_sectors, cache->sectors_per_block)) {
|
|
blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT);
|
|
blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
|
|
}
|
|
set_discard_limits(cache, limits);
|
|
}
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
static struct target_type cache_target = {
|
|
.name = "cache",
|
|
.version = {1, 5, 0},
|
|
.module = THIS_MODULE,
|
|
.ctr = cache_ctr,
|
|
.dtr = cache_dtr,
|
|
.map = cache_map,
|
|
.end_io = cache_end_io,
|
|
.postsuspend = cache_postsuspend,
|
|
.preresume = cache_preresume,
|
|
.resume = cache_resume,
|
|
.status = cache_status,
|
|
.message = cache_message,
|
|
.iterate_devices = cache_iterate_devices,
|
|
.merge = cache_bvec_merge,
|
|
.io_hints = cache_io_hints,
|
|
};
|
|
|
|
static int __init dm_cache_init(void)
|
|
{
|
|
int r;
|
|
|
|
r = dm_register_target(&cache_target);
|
|
if (r) {
|
|
DMERR("cache target registration failed: %d", r);
|
|
return r;
|
|
}
|
|
|
|
migration_cache = KMEM_CACHE(dm_cache_migration, 0);
|
|
if (!migration_cache) {
|
|
dm_unregister_target(&cache_target);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit dm_cache_exit(void)
|
|
{
|
|
dm_unregister_target(&cache_target);
|
|
kmem_cache_destroy(migration_cache);
|
|
}
|
|
|
|
module_init(dm_cache_init);
|
|
module_exit(dm_cache_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " cache target");
|
|
MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|