dm cache: add block sizes and total cache blocks to status output
Improve cache_status to emit:
<metadata block size> <#used metadata blocks>/<#total metadata blocks>
<cache block size> <#used cache blocks>/<#total cache blocks>
...
Adding the block sizes allows for easier calculation of the overall size
of both the metadata and cache devices. Adding <#total cache blocks>
provides useful context for how much of the cache is used.
Unfortunately these additions to the status will require updates to
users' scripts that monitor the cache status. But these changes help
provide more comprehensive information about the cache device and will
simplify tools that are being developed to manage dm-cache devices --
because they won't need to issue 3 operations to cobble together the
information that we can easily provide via a single status ioctl.
While updating the status documentation in cache.txt spaces were
tabify'd.
Requested-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1b1469e..11ad705 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2826,9 +2826,10 @@
/*
* Status format:
*
- * <#used metadata blocks>/<#total metadata blocks>
+ * <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> <#blocks in cache> <#dirty>
+ * <#demotions> <#promotions> <#dirty>
* <#features> <features>*
* <#core args> <core args>
* <#policy args> <policy args>*
@@ -2869,17 +2870,20 @@
residency = policy_residency(cache->policy);
- DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ",
+ DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %llu ",
+ (unsigned)(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
(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 long) from_cblock(residency),
- cache->nr_dirty);
+ (unsigned long long) from_cblock(cache->nr_dirty));
if (writethrough_mode(&cache->features))
DMEMIT("1 writethrough ");
@@ -3129,7 +3133,7 @@
static struct target_type cache_target = {
.name = "cache",
- .version = {1, 2, 0},
+ .version = {1, 3, 0},
.module = THIS_MODULE,
.ctr = cache_ctr,
.dtr = cache_dtr,