[lvm-devel] master - cache: LV supports cache segs with metadata format
Zdenek Kabelac
zkabelac at sourceware.org
Fri Mar 10 18:37:07 UTC 2017
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=518b814cdb806f70f99aaa168fca45495b18a4cf
Commit: 518b814cdb806f70f99aaa168fca45495b18a4cf
Parent: 4a394f410d571d8c8ef7c9f87df781df0f7988bd
Author: Zdenek Kabelac <zkabelac at redhat.com>
AuthorDate: Wed Mar 1 12:26:56 2017 +0100
Committer: Zdenek Kabelac <zkabelac at redhat.com>
CommitterDate: Fri Mar 10 19:33:01 2017 +0100
cache: LV supports cache segs with metadata format
Cache pool read/writes metadata_format within its segment type..
For CachePoolLV unselected metadata format is NOT stored in metadata.
For CacheLV when metadata format is not present/selected in lvm2 metadata,
it's automatically assumed to be the version 1 (backward compatible).
To ensure older lvm2 will not 'miss-read' metadata with new version 2,
such LV is marked with METADATA_FORMAT status flag (segment is
specifying metadata format). So when cache uses metadata format 2,
it will become inaccesible on older system without such support.
(kernel dm cache < 1.10, lvm2 < 2.02.169).
---
WHATS_NEW | 1 +
lib/cache_segtype/cache.c | 35 +++++++++++++++++++++++++++++++++++
lib/format_text/flags.c | 1 +
lib/metadata/metadata-exported.h | 5 ++++-
4 files changed, 41 insertions(+), 1 deletions(-)
diff --git a/WHATS_NEW b/WHATS_NEW
index d1efed0..4a5b0f6 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
Version 2.02.169 -
=====================================
+ Support cache segment with configurable metadata format.
Add allocation/cache_metadata_format profilable setttings.
Use function cache_set_params() for both lvcreate and lvconvert.
Skip rounding on cache chunk size boudary when create cache LV.
diff --git a/lib/cache_segtype/cache.c b/lib/cache_segtype/cache.c
index c378eda..985af68 100644
--- a/lib/cache_segtype/cache.c
+++ b/lib/cache_segtype/cache.c
@@ -52,6 +52,12 @@ static void _fix_missing_defaults(struct lv_segment *cpool_seg)
cpool_seg->policy_name);
}
+ if (cpool_seg->cache_metadata_format == CACHE_METADATA_FORMAT_UNSELECTED) {
+ cpool_seg->cache_metadata_format = CACHE_METADATA_FORMAT_1;
+ log_verbose("Cache pool %s uses implicit metadata format %u.",
+ display_lvname(cpool_seg->lv), cpool_seg->cache_metadata_format);
+ }
+
if (cpool_seg->cache_mode == CACHE_MODE_UNSELECTED) {
cpool_seg->cache_mode = CACHE_MODE_WHEN_MISSING;
log_verbose("Cache pool %s is missing cache mode, using %s.",
@@ -107,6 +113,16 @@ static int _cache_pool_text_import(struct lv_segment *seg,
return SEG_LOG_ERROR("Failed to duplicate policy in");
}
+ if (dm_config_has_node(sn, "metadata_format")) {
+ if (!dm_config_get_uint32(sn, "metadata_format", &seg->cache_metadata_format) ||
+ ((seg->cache_metadata_format != CACHE_METADATA_FORMAT_1) &&
+ (seg->cache_metadata_format != CACHE_METADATA_FORMAT_2)))
+ return SEG_LOG_ERROR("Unknown cache metadata format %u number in",
+ seg->cache_metadata_format);
+ if (seg->cache_metadata_format == CACHE_METADATA_FORMAT_2)
+ seg->lv->status |= LV_METADATA_FORMAT;
+ }
+
/*
* Read in policy args:
* policy_settings {
@@ -164,6 +180,25 @@ static int _cache_pool_text_export(const struct lv_segment *seg,
outf(f, "metadata = \"%s\"", seg->metadata_lv->name);
outf(f, "chunk_size = %" PRIu32, seg->chunk_size);
+ switch (seg->cache_metadata_format) {
+ case CACHE_METADATA_FORMAT_UNSELECTED:
+ /* Unselected format is not printed */
+ break;
+ case CACHE_METADATA_FORMAT_1:
+ /* If format 1 was already specified with cache pool, store it,
+ * otherwise format gets stored when LV is cached.
+ * NB: format 1 could be lost anytime, it's a default format.
+ * Older lvm2 tool can easily drop it.
+ */
+ case CACHE_METADATA_FORMAT_2: /* more in future ? */
+ outf(f, "metadata_format = " FMTu32, seg->cache_metadata_format);
+ break;
+ default:
+ log_error(INTERNAL_ERROR "LV %s is using unknown cache metadada format %u.",
+ display_lvname(seg->lv), seg->cache_metadata_format);
+ return 0;
+ }
+
/*
* Cache pool used by a cache LV holds data. Not ideal,
* but not worth to break backward compatibility, by shifting
diff --git a/lib/format_text/flags.c b/lib/format_text/flags.c
index 716e632..a9f81f5 100644
--- a/lib/format_text/flags.c
+++ b/lib/format_text/flags.c
@@ -67,6 +67,7 @@ static const struct flag _lv_flags[] = {
{LV_WRITEMOSTLY, "WRITEMOSTLY", STATUS_FLAG},
{LV_ACTIVATION_SKIP, "ACTIVATION_SKIP", COMPATIBLE_FLAG},
{LV_ERROR_WHEN_FULL, "ERROR_WHEN_FULL", COMPATIBLE_FLAG},
+ {LV_METADATA_FORMAT, "METADATA_FORMAT", STATUS_FLAG},
{LV_NOSCAN, NULL, 0},
{LV_TEMPORARY, NULL, 0},
{POOL_METADATA_SPARE, NULL, 0},
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 5c84bdf..c11899d 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -141,7 +141,8 @@
#define LV_RESHAPE_DELTA_DISKS_MINUS UINT64_C(0x0200000000000000) /* LV reshape flag delta disks minus image(s) */
#define LV_REMOVE_AFTER_RESHAPE UINT64_C(0x0400000000000000) /* LV needs to be removed after a shrinking reshape */
-/* Next unused flag: UINT64_C(0x0800000000000000) */
+#define LV_METADATA_FORMAT UINT64_C(0x0800000000000000) /* LV has segments with metadata format */
+/* Next unused flag: UINT64_C(0x1000000000000000) */
/* Format features flags */
#define FMT_SEGMENTS 0x00000001U /* Arbitrary segment params? */
@@ -503,6 +504,7 @@ struct lv_segment {
struct logical_volume *pool_lv; /* For thin, cache */
uint32_t device_id; /* For thin, 24bit */
+ cache_metadata_format_t cache_metadata_format;/* For cache_pool */
cache_mode_t cache_mode; /* For cache_pool */
const char *policy_name; /* For cache_pool */
struct dm_config_node *policy_settings; /* For cache_pool */
@@ -964,6 +966,7 @@ struct lvcreate_params {
uint32_t min_recovery_rate; /* RAID */
uint32_t max_recovery_rate; /* RAID */
+ cache_metadata_format_t cache_metadata_format; /* cache */
cache_mode_t cache_mode; /* cache */
const char *policy_name; /* cache */
struct dm_config_tree *policy_settings; /* cache */
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