[lvm-devel] stable-2.02 - pool: zero metadata
Zdenek Kabelac
zkabelac at sourceware.org
Sun Oct 18 21:02:29 UTC 2020
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=8ee2479dd0547ee6451da5b3e2ffca2f808c09a9
Commit: 8ee2479dd0547ee6451da5b3e2ffca2f808c09a9
Parent: 7a06bc240001a18db8da8a9befa5b6e9ddbcdcb5
Author: Zdenek Kabelac <zkabelac at redhat.com>
AuthorDate: Wed Jun 24 12:11:21 2020 +0200
Committer: Zdenek Kabelac <zkabelac at redhat.com>
CommitterDate: Sun Oct 18 21:27:51 2020 +0200
pool: zero metadata
To avoid polution of metadata with some 'garbage' content or eventualy
some leak of stale data in case user want to upload metadata somewhere,
ensure upon allocation the metadata device is fully zeroed.
Behaviour may slow down allocation of thin-pool or cache-pool a bit
so the old behaviour can be restored with lvm.conf setting:
allocation/zero_metadata=0
TODO: add zeroing for extension of metadata volume.
---
WHATS_NEW | 1 +
conf/example.conf.in | 6 +++++-
lib/config/config_settings.h | 5 ++++-
lib/config/defaults.h | 1 +
lib/metadata/lv_manip.c | 28 +++++++++++++++++++++-------
lib/metadata/metadata-exported.h | 2 ++
lib/metadata/pool_manip.c | 6 ++++--
7 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/WHATS_NEW b/WHATS_NEW
index e7245447b..9c2df1515 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
Version 2.02.188 -
==================================
+ Zero pool metadata on allocation (disable with allocation/zero_metadata=0).
Failure in zeroing or wiping will fail command (bypass with -Zn, -Wn).
Fix support for lvconvert --repair used by foreign apps (i.e. Docker).
Support interruption for bcache waiting.
diff --git a/conf/example.conf.in b/conf/example.conf.in
index 29b0df497..a57c66e40 100644
--- a/conf/example.conf.in
+++ b/conf/example.conf.in
@@ -467,7 +467,7 @@ allocation {
# This configuration option does not have a default value defined.
# Configuration option allocation/thin_pool_metadata_require_separate_pvs.
- # Thin pool metdata and data will always use different PVs.
+ # Thin pool metadata and data will always use different PVs.
thin_pool_metadata_require_separate_pvs = 0
# Configuration option allocation/thin_pool_zero.
@@ -505,6 +505,10 @@ allocation {
# This configuration option has an automatic default value.
# thin_pool_chunk_size_policy = "generic"
+ # Configuration option allocation/zero_metadata.
+ # Zero whole metadata area before use with thin or cache pool.
+ zero_metadata = 1
+
# Configuration option allocation/thin_pool_chunk_size.
# The minimal chunk size in KiB for thin pool volumes.
# Larger chunk sizes may improve performance for plain thin volumes,
diff --git a/lib/config/config_settings.h b/lib/config/config_settings.h
index 429bff14e..d23ae49ff 100644
--- a/lib/config/config_settings.h
+++ b/lib/config/config_settings.h
@@ -594,7 +594,7 @@ cfg(allocation_cache_pool_max_chunks_CFG, "cache_pool_max_chunks", allocation_CF
"Using cache pool with more chunks may degrade cache performance.\n")
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, 0, NULL,
- "Thin pool metdata and data will always use different PVs.\n")
+ "Thin pool metadata and data will always use different PVs.\n")
cfg(allocation_thin_pool_zero_CFG, "thin_pool_zero", allocation_CFG_SECTION, CFG_PROFILABLE | CFG_PROFILABLE_METADATA | CFG_DEFAULT_COMMENTED, CFG_TYPE_BOOL, DEFAULT_THIN_POOL_ZERO, vsn(2, 2, 99), NULL, 0, NULL,
"Thin pool data chunks are zeroed before they are first used.\n"
@@ -625,6 +625,9 @@ cfg(allocation_thin_pool_chunk_size_policy_CFG, "thin_pool_chunk_size_policy", a
" 512KiB.\n"
"#\n")
+cfg(allocation_zero_metadata_CFG, "zero_metadata", allocation_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_ZERO_METADATA, vsn(2, 2, 188), NULL, 0, NULL,
+ "Zero whole metadata area before use with thin or cache pool.\n")
+
cfg_runtime(allocation_thin_pool_chunk_size_CFG, "thin_pool_chunk_size", allocation_CFG_SECTION, CFG_PROFILABLE | CFG_PROFILABLE_METADATA | CFG_DEFAULT_UNDEFINED, CFG_TYPE_INT, vsn(2, 2, 99), 0, NULL,
"The minimal chunk size in KiB for thin pool volumes.\n"
"Larger chunk sizes may improve performance for plain thin volumes,\n"
diff --git a/lib/config/defaults.h b/lib/config/defaults.h
index 6d3c37c81..2ffad243e 100644
--- a/lib/config/defaults.h
+++ b/lib/config/defaults.h
@@ -116,6 +116,7 @@
#define DEFAULT_THIN_POOL_DISCARDS "passdown"
#define DEFAULT_THIN_POOL_ZERO 1
#define DEFAULT_POOL_METADATA_SPARE 1 /* thin + cache */
+#define DEFAULT_ZERO_METADATA 1 /* thin + cache */
#ifdef CACHE_CHECK_NEEDS_CHECK
# define DEFAULT_CACHE_CHECK_OPTION1 "-q"
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index c4fabf5a0..0e58d4fa9 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -7183,8 +7183,9 @@ int wipe_lv(struct logical_volume *lv, struct wipe_params wp)
struct device *dev;
char name[PATH_MAX];
uint64_t zero_sectors;
+ int zero_metadata;
- if (!wp.do_zero && !wp.do_wipe_signatures)
+ if (!wp.do_zero && !wp.do_wipe_signatures && !wp.is_metadata)
/* nothing to do */
return 1;
@@ -7236,17 +7237,29 @@ int wipe_lv(struct logical_volume *lv, struct wipe_params wp)
}
}
- if (wp.do_zero) {
- zero_sectors = wp.zero_sectors ? : UINT64_C(4096) >> SECTOR_SHIFT;
-
- if (zero_sectors > lv->size)
+ if (wp.do_zero || wp.is_metadata) {
+ zero_metadata = !wp.is_metadata ? 0 :
+ find_config_tree_bool(lv->vg->cmd, allocation_zero_metadata_CFG, NULL);
+ if (zero_metadata) {
+ log_debug("Metadata logical volume %s will be fully zeroed.",
+ display_lvname(lv));
zero_sectors = lv->size;
+ } else {
+ if (wp.is_metadata) /* Verbosely notify metadata will not be fully zeroed */
+ log_verbose("Metadata logical volume %s not fully zeroed and may contain stale data.",
+ display_lvname(lv));
+ zero_sectors = wp.zero_sectors ? : UINT64_C(4096) >> SECTOR_SHIFT;
+
+ if (zero_sectors > lv->size)
+ zero_sectors = lv->size;
+ }
log_verbose("Initializing %s of logical volume %s with value %d.",
display_size(lv->vg->cmd, zero_sectors),
display_lvname(lv), wp.zero_value);
- if ((wp.zero_value && !dev_set_bytes(dev, UINT64_C(0),
+ if ((!wp.is_metadata &&
+ wp.zero_value && !dev_set_bytes(dev, UINT64_C(0),
(size_t) zero_sectors << SECTOR_SHIFT,
(uint8_t)wp.zero_value)) ||
!dev_write_zeros(dev, UINT64_C(0), (size_t) zero_sectors << SECTOR_SHIFT)) {
@@ -8088,7 +8101,8 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
.do_zero = lp->zero,
.do_wipe_signatures = lp->wipe_signatures,
.yes = lp->yes,
- .force = lp->force
+ .force = lp->force,
+ .is_metadata = lp->is_metadata,
})) {
log_error("Aborting. Failed to wipe %s.", lp->snapshot
? "snapshot exception store" : "start of new LV");
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index f64f53f86..8f173059b 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -780,6 +780,7 @@ struct wipe_params {
int do_wipe_signatures; /* should we wipe known signatures found on LV? */
int yes; /* answer yes automatically to all questions */
force_t force; /* force mode */
+ int is_metadata; /* wipe volume is metadata LV */
};
/* Zero out LV and/or wipe signatures */
@@ -943,6 +944,7 @@ struct lvcreate_params {
int thin_chunk_size_calc_policy;
unsigned suppress_zero_warn : 1;
unsigned needs_lockd_init : 1;
+ unsigned is_metadata : 1; /* created LV will be used as metadata LV (and can be zeroed) */
const char *vg_name; /* only-used when VG is not yet opened (in /tools) */
const char *lv_name; /* all */
diff --git a/lib/metadata/pool_manip.c b/lib/metadata/pool_manip.c
index 1381f29bf..a93e230be 100644
--- a/lib/metadata/pool_manip.c
+++ b/lib/metadata/pool_manip.c
@@ -532,8 +532,8 @@ int create_pool(struct logical_volume *pool_lv,
display_lvname(pool_lv));
goto bad;
}
- /* Clear 4KB of pool metadata device. */
- if (!(r = wipe_lv(pool_lv, (struct wipe_params) { .do_zero = 1 }))) {
+ /* Clear pool metadata device. */
+ if (!(r = wipe_lv(pool_lv, (struct wipe_params) { .is_metadata = 1 }))) {
log_error("Aborting. Failed to wipe pool metadata %s.",
display_lvname(pool_lv));
}
@@ -614,6 +614,7 @@ struct logical_volume *alloc_pool_metadata(struct logical_volume *pool_lv,
.tags = DM_LIST_HEAD_INIT(lvc.tags),
.temporary = 1,
.zero = 1,
+ .is_metadata = 1,
};
if (!(lvc.segtype = get_segtype_from_string(pool_lv->vg->cmd, SEG_TYPE_NAME_STRIPED)))
@@ -650,6 +651,7 @@ static struct logical_volume *_alloc_pool_metadata_spare(struct volume_group *vg
.tags = DM_LIST_HEAD_INIT(lp.tags),
.temporary = 1,
.zero = 1,
+ .is_metadata = 1,
};
if (!(lp.segtype = get_segtype_from_string(vg->cmd, SEG_TYPE_NAME_STRIPED)))
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