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-rw-r--r--drivers/md/dm-cache-target.c94
1 files changed, 87 insertions, 7 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 41e7cfdb450d..2c66315553f2 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2817,17 +2817,86 @@ static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
return 0;
}
+/*
+ * The discard block size in the on disk metadata is not
+ * neccessarily the same as we're currently using. So we have to
+ * be careful to only set the discarded attribute if we know it
+ * covers a complete block of the new size.
+ */
+struct discard_load_info {
+ struct cache *cache;
+
+ /*
+ * These blocks are sized using the on disk dblock size, rather
+ * than the current one.
+ */
+ dm_block_t block_size;
+ dm_block_t discard_begin, discard_end;
+};
+
+static void discard_load_info_init(struct cache *cache,
+ struct discard_load_info *li)
+{
+ li->cache = cache;
+ li->discard_begin = li->discard_end = 0;
+}
+
+static void set_discard_range(struct discard_load_info *li)
+{
+ sector_t b, e;
+
+ if (li->discard_begin == li->discard_end)
+ return;
+
+ /*
+ * Convert to sectors.
+ */
+ b = li->discard_begin * li->block_size;
+ e = li->discard_end * li->block_size;
+
+ /*
+ * Then convert back to the current dblock size.
+ */
+ b = dm_sector_div_up(b, li->cache->discard_block_size);
+ sector_div(e, li->cache->discard_block_size);
+
+ /*
+ * The origin may have shrunk, so we need to check we're still in
+ * bounds.
+ */
+ if (e > from_dblock(li->cache->discard_nr_blocks))
+ e = from_dblock(li->cache->discard_nr_blocks);
+
+ for (; b < e; b++)
+ set_discard(li->cache, to_dblock(b));
+}
+
static int load_discard(void *context, sector_t discard_block_size,
dm_dblock_t dblock, bool discard)
{
- struct cache *cache = context;
+ struct discard_load_info *li = context;
- /* FIXME: handle mis-matched block size */
+ li->block_size = discard_block_size;
- if (discard)
- set_discard(cache, dblock);
- else
- clear_discard(cache, dblock);
+ if (discard) {
+ if (from_dblock(dblock) == li->discard_end)
+ /*
+ * We're already in a discard range, just extend it.
+ */
+ li->discard_end = li->discard_end + 1ULL;
+
+ else {
+ /*
+ * Emit the old range and start a new one.
+ */
+ set_discard_range(li);
+ li->discard_begin = from_dblock(dblock);
+ li->discard_end = li->discard_begin + 1ULL;
+ }
+ } else {
+ set_discard_range(li);
+ li->discard_begin = li->discard_end = 0;
+ }
return 0;
}
@@ -2911,11 +2980,22 @@ static int cache_preresume(struct dm_target *ti)
}
if (!cache->loaded_discards) {
- r = dm_cache_load_discards(cache->cmd, load_discard, cache);
+ struct discard_load_info li;
+
+ /*
+ * The discard bitset could have been resized, or the
+ * discard block size changed. To be safe we start by
+ * setting every dblock to not discarded.
+ */
+ clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
+
+ discard_load_info_init(cache, &li);
+ r = dm_cache_load_discards(cache->cmd, load_discard, &li);
if (r) {
DMERR("could not load origin discards");
return r;
}
+ set_discard_range(&li);
cache->loaded_discards = true;
}