[lvm-devel] master - cache: detect smq policy presence
Zdenek Kabelac
zkabelac at fedoraproject.org
Wed Aug 12 12:40:53 UTC 2015
Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=8a74d1ec79d209aa8bce51821836179afe7d48f9
Commit: 8a74d1ec79d209aa8bce51821836179afe7d48f9
Parent: 694c88e031fb44f957c75bea369b898e1dedf932
Author: Zdenek Kabelac <zkabelac at redhat.com>
AuthorDate: Thu Jul 23 11:32:09 2015 +0200
Committer: Zdenek Kabelac <zkabelac at redhat.com>
CommitterDate: Wed Aug 12 14:11:17 2015 +0200
cache: detect smq policy presence
Add code to detect available cache features.
Support policy_mq & policy_smq features which might be disabled.
Introduce global_cache_disabled_features_CFG.
---
lib/cache_segtype/cache.c | 73 ++++++++++++++++++++++++++++++++++++++++--
lib/config/config_settings.h | 8 ++++
lib/metadata/segtype.h | 3 ++
3 files changed, 81 insertions(+), 3 deletions(-)
diff --git a/lib/cache_segtype/cache.c b/lib/cache_segtype/cache.c
index 18c0168..d74fbf1 100644
--- a/lib/cache_segtype/cache.c
+++ b/lib/cache_segtype/cache.c
@@ -25,6 +25,11 @@
#include "lv_alloc.h"
#include "defaults.h"
+static const char _cache_module[] = "cache";
+
+/* TODO: using static field here, maybe should be a part of segment_type */
+static unsigned _feature_mask;
+
#define SEG_LOG_ERROR(t, p...) \
log_error(t " segment %s of logical volume %s.", ## p, \
dm_config_parent_name(sn), seg->lv->name), 0;
@@ -168,9 +173,26 @@ static int _target_present(struct cmd_context *cmd,
const struct lv_segment *seg __attribute__((unused)),
unsigned *attributes __attribute__((unused)))
{
- uint32_t maj, min, patchlevel;
+ /* List of features with their kernel target version */
+ static const struct feature {
+ uint32_t maj;
+ uint32_t min;
+ unsigned cache_feature;
+ const char feature[12];
+ const char module[12]; /* check dm-%s */
+ } _features[] = {
+ { 1, 3, CACHE_FEATURE_POLICY_MQ, "policy_mq", "cache-mq" },
+ { 1, 8, CACHE_FEATURE_POLICY_SMQ, "policy_smq", "cache-smq" },
+ };
+ static const char _lvmconf[] = "global/cache_disabled_features";
+ static unsigned _attrs = 0;
static int _cache_checked = 0;
static int _cache_present = 0;
+ uint32_t maj, min, patchlevel;
+ unsigned i;
+ const struct dm_config_node *cn;
+ const struct dm_config_value *cv;
+ const char *str;
if (!_cache_checked) {
_cache_present = target_present(cmd, "cache", 1);
@@ -184,11 +206,53 @@ static int _target_present(struct cmd_context *cmd,
if ((maj < 1) ||
((maj == 1) && (min < 3))) {
- log_error("The cache kernel module is version %u.%u.%u."
- " Version 1.3.0+ is required.",
+ _cache_present = 0;
+ log_error("The cache kernel module is version %u.%u.%u. "
+ "Version 1.3.0+ is required.",
maj, min, patchlevel);
return 0;
}
+
+
+ for (i = 0; i < DM_ARRAY_SIZE(_features); ++i) {
+ if (((maj > _features[i].maj) ||
+ (maj == _features[i].maj && min >= _features[i].min)) &&
+ (!_features[i].module[0] || module_present(cmd, _features[i].module)))
+ _attrs |= _features[i].cache_feature;
+ else
+ log_very_verbose("Target %s does not support %s.",
+ _cache_module, _features[i].feature);
+ }
+ }
+
+ if (attributes) {
+ if (!_feature_mask) {
+ /* Support runtime lvm.conf changes, N.B. avoid 32 feature */
+ if ((cn = find_config_tree_array(cmd, global_cache_disabled_features_CFG, NULL))) {
+ for (cv = cn->v; cv; cv = cv->next) {
+ if (cv->type != DM_CFG_STRING) {
+ log_error("Ignoring invalid string in config file %s.",
+ _lvmconf);
+ continue;
+ }
+ str = cv->v.str;
+ if (!*str)
+ continue;
+ for (i = 0; i < DM_ARRAY_SIZE(_features); ++i)
+ if (strcasecmp(str, _features[i].feature) == 0)
+ _feature_mask |= _features[i].cache_feature;
+ }
+ }
+
+ _feature_mask = ~_feature_mask;
+
+ for (i = 0; i < DM_ARRAY_SIZE(_features); ++i)
+ if ((_attrs & _features[i].cache_feature) &&
+ !(_feature_mask & _features[i].cache_feature))
+ log_very_verbose("Target %s %s support disabled by %s",
+ _cache_module, _features[i].feature, _lvmconf);
+ }
+ *attributes = _attrs & _feature_mask;
}
return _cache_present;
@@ -376,5 +440,8 @@ int init_cache_segtypes(struct cmd_context *cmd,
return_0;
log_very_verbose("Initialised segtype: %s", segtype->name);
+ /* Reset mask for recalc */
+ _feature_mask = 0;
+
return 1;
}
diff --git a/lib/config/config_settings.h b/lib/config/config_settings.h
index deb17ef..c8461f7 100644
--- a/lib/config/config_settings.h
+++ b/lib/config/config_settings.h
@@ -909,6 +909,14 @@ cfg_array(global_thin_disabled_features_CFG, "thin_disabled_features", global_CF
"Example:\n"
"thin_disabled_features = [ \"discards\", \"block_size\" ]\n")
+cfg_array(global_cache_disabled_features_CFG, "cache_disabled_features", global_CFG_SECTION, CFG_ALLOW_EMPTY | CFG_DEFAULT_UNDEFINED, CFG_TYPE_STRING, NULL, vsn(2, 2, 126), NULL, 0, NULL,
+ "Features to not use in the cache driver.\n"
+ "This can be helpful for testing, or to avoid\n"
+ "using a feature that is causing problems.\n"
+ "Features: policy_mq, policy_smq.\n"
+ "Example:\n"
+ "cache_disabled_features = [ \"policy_smq\" ]\n")
+
cfg(global_cache_check_executable_CFG, "cache_check_executable", global_CFG_SECTION, CFG_ALLOW_EMPTY | CFG_DEFAULT_COMMENTED, CFG_TYPE_STRING, CACHE_CHECK_CMD, vsn(2, 2, 108), "@CACHE_CHECK_CMD@", 0, NULL,
"The full path to the cache_check command.\n"
"LVM uses this command to check that a cache metadata\n"
diff --git a/lib/metadata/segtype.h b/lib/metadata/segtype.h
index 4b2df78..a80d5ed 100644
--- a/lib/metadata/segtype.h
+++ b/lib/metadata/segtype.h
@@ -191,6 +191,9 @@ int init_thin_segtypes(struct cmd_context *cmd, struct segtype_library *seglib);
int init_cache_segtypes(struct cmd_context *cmd, struct segtype_library *seglib);
#endif
+#define CACHE_FEATURE_POLICY_MQ (1U << 0)
+#define CACHE_FEATURE_POLICY_SMQ (1U << 1)
+
#define SNAPSHOT_FEATURE_FIXED_LEAK (1U << 0) /* version 1.12 */
#ifdef SNAPSHOT_INTERNAL
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