dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size"
This reverts commit d132cc6d9e
because we
actually do want to allow the discard blocksize to be larger than the
cache blocksize. Further dm-cache discard changes will make this
possible.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
parent
1bad9bc4ee
commit
08b184514f
1 changed files with 34 additions and 3 deletions
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@ -238,7 +238,7 @@ struct cache {
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*/
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*/
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dm_dblock_t discard_nr_blocks;
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dm_dblock_t discard_nr_blocks;
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unsigned long *discard_bitset;
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unsigned long *discard_bitset;
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uint32_t discard_block_size;
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uint32_t discard_block_size; /* a power of 2 times sectors per block */
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/*
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/*
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* Rather than reconstructing the table line for the status we just
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* Rather than reconstructing the table line for the status we just
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@ -2197,6 +2197,35 @@ static int create_cache_policy(struct cache *cache, struct cache_args *ca,
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return 0;
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return 0;
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}
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}
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/*
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* We want the discard block size to be a power of two, at least the size
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* of the cache block size, and have no more than 2^14 discard blocks
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* across the origin.
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*/
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#define MAX_DISCARD_BLOCKS (1 << 14)
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static bool too_many_discard_blocks(sector_t discard_block_size,
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sector_t origin_size)
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{
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(void) sector_div(origin_size, discard_block_size);
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return origin_size > MAX_DISCARD_BLOCKS;
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}
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static sector_t calculate_discard_block_size(sector_t cache_block_size,
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sector_t origin_size)
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{
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sector_t discard_block_size;
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discard_block_size = roundup_pow_of_two(cache_block_size);
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if (origin_size)
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while (too_many_discard_blocks(discard_block_size, origin_size))
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discard_block_size *= 2;
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return discard_block_size;
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}
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#define DEFAULT_MIGRATION_THRESHOLD 2048
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#define DEFAULT_MIGRATION_THRESHOLD 2048
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static int cache_create(struct cache_args *ca, struct cache **result)
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static int cache_create(struct cache_args *ca, struct cache **result)
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@ -2320,7 +2349,9 @@ static int cache_create(struct cache_args *ca, struct cache **result)
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}
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}
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clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
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clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
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cache->discard_block_size = cache->sectors_per_block;
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cache->discard_block_size =
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calculate_discard_block_size(cache->sectors_per_block,
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cache->origin_sectors);
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cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks);
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cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks);
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cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
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cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
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if (!cache->discard_bitset) {
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if (!cache->discard_bitset) {
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@ -3099,7 +3130,7 @@ static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
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/*
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/*
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* FIXME: these limits may be incompatible with the cache device
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* FIXME: these limits may be incompatible with the cache device
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*/
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*/
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limits->max_discard_sectors = cache->discard_block_size;
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limits->max_discard_sectors = cache->discard_block_size * 1024;
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limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
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limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
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}
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}
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