[lvm-devel] [LVM PATCH 2/3] cache: Allocation code changes to support cache pool
Jonathan Brassow
jbrassow at redhat.com
Tue Jan 28 14:16:08 UTC 2014
Cache pools require a data and metadata area (like thin pools). Unlike
thin pool, if 'cache_pool_metadata_require_separate_pvs' is not set to
'1', the metadata and data area will be allocated from the same device.
It is also done in a manner similar to RAID, where a single chunk of
space is allocated and then split to form the metadata and data device -
ensuring that they are together.
---
conf/example.conf.in | 4 ++++
lib/config/config_settings.h | 1 +
lib/config/defaults.h | 2 ++
lib/metadata/lv_manip.c | 39 ++++++++++++++++++++++++++++++++-------
4 files changed, 39 insertions(+), 7 deletions(-)
diff --git a/conf/example.conf.in b/conf/example.conf.in
index 0f73cf3..7b98b4b 100644
--- a/conf/example.conf.in
+++ b/conf/example.conf.in
@@ -301,6 +301,10 @@ allocation {
# until version 2.02.85.
mirror_logs_require_separate_pvs = 0
+ # Set to 1 to guarantee that cache_pool metadata will always be
+ # placed on different PVs from the cache_pool data.
+ cache_pool_metadata_require_separate_pvs = 0
+
# Set to 1 to guarantee that thin pool metadata will always
# be placed on different PVs from the pool data.
thin_pool_metadata_require_separate_pvs = 0
diff --git a/lib/config/config_settings.h b/lib/config/config_settings.h
index 1546b3f..2c6953b 100644
--- a/lib/config/config_settings.h
+++ b/lib/config/config_settings.h
@@ -107,6 +107,7 @@ cfg(allocation_maximise_cling_CFG, "maximise_cling", allocation_CFG_SECTION, 0,
cfg(allocation_use_blkid_wiping_CFG, "use_blkid_wiping", allocation_CFG_SECTION, 0, CFG_TYPE_BOOL, 1, vsn(2, 2, 105), NULL)
cfg(allocation_wipe_signatures_when_zeroing_new_lvs_CFG, "wipe_signatures_when_zeroing_new_lvs", allocation_CFG_SECTION, 0, CFG_TYPE_BOOL, 1, vsn(2, 2, 105), NULL)
cfg(allocation_mirror_logs_require_separate_pvs_CFG, "mirror_logs_require_separate_pvs", allocation_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_MIRROR_LOGS_REQUIRE_SEPARATE_PVS, vsn(2, 2, 85), NULL)
+cfg(allocation_cache_pool_metadata_require_separate_pvs_CFG, "cache_pool_metadata_require_separate_pvs", allocation_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_CACHE_POOL_METADATA_REQUIRE_SEPARATE_PVS, vsn(2, 2, 89), NULL)
cfg(allocation_thin_pool_metadata_require_separate_pvs_CFG, "thin_pool_metadata_require_separate_pvs", allocation_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_THIN_POOL_METADATA_REQUIRE_SEPARATE_PVS, vsn(2, 2, 89), NULL)
cfg(allocation_thin_pool_zero_CFG, "thin_pool_zero", allocation_CFG_SECTION, CFG_PROFILABLE, CFG_TYPE_BOOL, DEFAULT_THIN_POOL_ZERO, vsn(2, 2, 99), NULL)
cfg(allocation_thin_pool_discards_CFG, "thin_pool_discards", allocation_CFG_SECTION, CFG_PROFILABLE, CFG_TYPE_STRING, DEFAULT_THIN_POOL_DISCARDS, vsn(2, 2, 99), NULL)
diff --git a/lib/config/defaults.h b/lib/config/defaults.h
index 141b7ae..a388e13 100644
--- a/lib/config/defaults.h
+++ b/lib/config/defaults.h
@@ -79,6 +79,8 @@
#define DEFAULT_THIN_POOL_ZERO 1
#define DEFAULT_POOL_METADATA_SPARE 1
+#define DEFAULT_CACHE_POOL_METADATA_REQUIRE_SEPARATE_PVS 0
+
#define DEFAULT_UMASK 0077
#ifdef LVM1_FALLBACK
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 2e240fc..653391f 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -924,6 +924,9 @@ struct alloc_handle {
* that is new_extents + log_len and then split that between two
* allocated areas when found. 'alloc_and_split_meta' indicates
* that this is the desired dynamic.
+ *
+ * This same idea is used by cache LVs to get the metadata device
+ * and data device allocated together.
*/
unsigned alloc_and_split_meta;
@@ -1115,6 +1118,7 @@ static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
* a correct area_multiple.
*/
ah->area_multiple = _calc_area_multiple(segtype, area_count + parity_count, stripes);
+ //FIXME: s/mirror_logs_separate/metadata_separate/ so it can be used by otehrs?
ah->mirror_logs_separate = find_config_tree_bool(cmd, allocation_mirror_logs_require_separate_pvs_CFG, NULL);
if (segtype_is_raid(segtype)) {
@@ -1137,12 +1141,30 @@ static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
ah->log_len = 0;
}
} else if (segtype_is_thin_pool(segtype)) {
- ah->log_area_count = metadata_area_count;
- /* thin_pool uses region_size to pass metadata size in extents */
+ /*
+ * thin_pool uses ah->region_size to
+ * pass metadata size in extents
+ */
ah->log_len = ah->region_size;
+ ah->log_area_count = metadata_area_count;
ah->region_size = 0;
ah->mirror_logs_separate =
find_config_tree_bool(cmd, allocation_thin_pool_metadata_require_separate_pvs_CFG, NULL);
+ } else if (segtype_is_cache_pool(segtype)) {
+ /*
+ * Like thin_pool, cache_pool uses ah->region_size to
+ * pass metadata size in extents
+ */
+ ah->log_len = ah->region_size;
+ /* use metadata_area_count, not log_area_count */
+ ah->metadata_area_count = metadata_area_count;
+ ah->region_size = 0;
+ ah->mirror_logs_separate =
+ find_config_tree_bool(cmd, allocation_cache_pool_metadata_require_separate_pvs_CFG, NULL);
+ if (!ah->mirror_logs_separate) {
+ ah->alloc_and_split_meta = 1;
+ ah->new_extents += ah->log_len;
+ }
} else {
ah->log_area_count = metadata_area_count;
ah->log_len = !metadata_area_count ? 0 :
@@ -1956,14 +1978,15 @@ static void _report_needed_allocation_space(struct alloc_handle *ah,
uint32_t parallel_areas_count, parallel_area_size;
uint32_t metadata_count, metadata_size;
- parallel_area_size = (ah->new_extents - alloc_state->allocated) / ah->area_multiple -
- ((ah->alloc_and_split_meta) ? ah->log_len : 0);
+ parallel_area_size = ah->new_extents - alloc_state->allocated;
+ parallel_area_size /= ah->area_multiple;
+ parallel_area_size -= (ah->alloc_and_split_meta) ? ah->log_len : 0;
parallel_areas_count = ah->area_count + ah->parity_count;
metadata_size = ah->log_len;
if (ah->alloc_and_split_meta) {
- metadata_type = "RAID metadata area";
+ metadata_type = "metadata area";
metadata_count = parallel_areas_count;
} else {
metadata_type = "mirror log";
@@ -1975,8 +1998,10 @@ static void _report_needed_allocation_space(struct alloc_handle *ah,
log_debug_alloc(" %" PRIu32 " (%" PRIu32 " data/%" PRIu32
" parity) parallel areas of %" PRIu32 " extents each",
parallel_areas_count, ah->area_count, ah->parity_count, parallel_area_size);
- log_debug_alloc(" %" PRIu32 " %ss of %" PRIu32 " extents each",
- metadata_count, metadata_type, metadata_size);
+ log_debug_alloc(" %" PRIu32 " %s%s of %" PRIu32 " extents each",
+ metadata_count, metadata_type,
+ (metadata_count == 1) ? "" : "s",
+ metadata_size);
}
/*
* Returns 1 regardless of whether any space was found, except on error.
--
1.7.7.6
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