[lvm-devel] master - keep track of which mdas have old metadata in lvmcache
David Teigland
teigland at sourceware.org
Fri Jun 7 21:08:08 UTC 2019
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=b2447e3538db370d1e12d328c25ca1f078ddabf6
Commit: b2447e3538db370d1e12d328c25ca1f078ddabf6
Parent: 0b18c25d934564015402de33e15a267045ed1b8c
Author: David Teigland <teigland at redhat.com>
AuthorDate: Tue Feb 5 13:09:56 2019 -0600
Committer: David Teigland <teigland at redhat.com>
CommitterDate: Fri Jun 7 15:54:04 2019 -0500
keep track of which mdas have old metadata in lvmcache
This will be used for more advanced repair in a
subsequent commit.
---
lib/cache/lvmcache.c | 173 ++++++++++++++++++++++++++++++++++++++++----------
lib/cache/lvmcache.h | 10 ++-
2 files changed, 145 insertions(+), 38 deletions(-)
diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index a860660..f54eff0 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -42,6 +42,10 @@ struct lvmcache_info {
uint32_t status;
bool mda1_bad; /* label scan found bad metadata in mda1 */
bool mda2_bad; /* label scan found bad metadata in mda2 */
+ bool summary_seqno_mismatch; /* two mdas on this dev has mismatching metadata */
+ int summary_seqno; /* vg seqno found on this dev during scan */
+ int mda1_seqno;
+ int mda2_seqno;
};
/* One per VG */
@@ -61,7 +65,7 @@ struct lvmcache_vginfo {
uint32_t mda_checksum;
size_t mda_size;
int seqno;
- int scan_summary_mismatch; /* vgsummary from devs had mismatching seqno or checksum */
+ bool scan_summary_mismatch; /* vgsummary from devs had mismatching seqno or checksum */
};
static struct dm_hash_table *_pvid_hash = NULL;
@@ -1515,12 +1519,9 @@ int lvmcache_add_orphan_vginfo(const char *vgname, struct format_type *fmt)
}
/*
- * FIXME: get rid of other callers of this function which call it
- * in odd cases to "fix up" some bit of lvmcache state. Make those
- * callers fix up what they need to directly, and leave this function
- * with one purpose and caller.
+ * Returning 0 causes the caller to remove the info struct for this
+ * device from lvmcache, which will make it look like a missing device.
*/
-
int lvmcache_update_vgname_and_id(struct lvmcache_info *info, struct lvmcache_vgsummary *vgsummary)
{
const char *vgname = vgsummary->vgname;
@@ -1546,6 +1547,7 @@ int lvmcache_update_vgname_and_id(struct lvmcache_info *info, struct lvmcache_vg
* Puts the vginfo into the vgname hash table.
*/
if (!_lvmcache_update_vgname(info, vgname, vgid, vgsummary->vgstatus, vgsummary->creation_host, info->fmt)) {
+ /* shouldn't happen, internal error */
log_error("Failed to update VG %s info in lvmcache.", vgname);
return 0;
}
@@ -1554,6 +1556,7 @@ int lvmcache_update_vgname_and_id(struct lvmcache_info *info, struct lvmcache_vg
* Puts the vginfo into the vgid hash table.
*/
if (!_lvmcache_update_vgid(info, info->vginfo, vgid)) {
+ /* shouldn't happen, internal error */
log_error("Failed to update VG %s info in lvmcache.", vgname);
return 0;
}
@@ -1569,50 +1572,114 @@ int lvmcache_update_vgname_and_id(struct lvmcache_info *info, struct lvmcache_vg
if (!vgsummary->seqno && !vgsummary->mda_size && !vgsummary->mda_checksum)
return 1;
+ /*
+ * Keep track of which devs/mdas have old versions of the metadata.
+ * The values we keep in vginfo are from the metadata with the largest
+ * seqno. One dev may have more recent metadata than another dev, and
+ * one mda may have more recent metadata than the other mda on the same
+ * device.
+ *
+ * When a device holds old metadata, the info struct for the device
+ * remains in lvmcache, so the device is not treated as missing.
+ * Also the mda struct containing the old metadata is kept on
+ * info->mdas. This means that vg_read will read metadata from
+ * the mda again (and probably see the same old metadata). It
+ * also means that vg_write will use the mda to write new metadata
+ * into the mda that currently has the old metadata.
+ */
+ if (vgsummary->mda_num == 1)
+ info->mda1_seqno = vgsummary->seqno;
+ else if (vgsummary->mda_num == 2)
+ info->mda2_seqno = vgsummary->seqno;
+
+ if (!info->summary_seqno)
+ info->summary_seqno = vgsummary->seqno;
+ else {
+ if (info->summary_seqno == vgsummary->seqno) {
+ /* This mda has the same metadata as the prev mda on this dev. */
+ return 1;
+
+ } else if (info->summary_seqno > vgsummary->seqno) {
+ /* This mda has older metadata than the prev mda on this dev. */
+ info->summary_seqno_mismatch = true;
+
+ } else if (info->summary_seqno < vgsummary->seqno) {
+ /* This mda has newer metadata than the prev mda on this dev. */
+ info->summary_seqno_mismatch = true;
+ info->summary_seqno = vgsummary->seqno;
+ }
+ }
+
+ /* this shouldn't happen */
if (!(vginfo = info->vginfo))
return 1;
if (!vginfo->seqno) {
vginfo->seqno = vgsummary->seqno;
+ vginfo->mda_checksum = vgsummary->mda_checksum;
+ vginfo->mda_size = vgsummary->mda_size;
- log_debug_cache("lvmcache %s: VG %s: set seqno to %d",
- dev_name(info->dev), vginfo->vgname, vginfo->seqno);
+ log_debug_cache("lvmcache %s mda%d VG %s set seqno %u checksum %x mda_size %zu",
+ dev_name(info->dev), vgsummary->mda_num, vgname,
+ vgsummary->seqno, vgsummary->mda_checksum, vgsummary->mda_size);
+ goto update_vginfo;
+
+ } else if (vgsummary->seqno < vginfo->seqno) {
+ vginfo->scan_summary_mismatch = true;
- } else if (vgsummary->seqno != vginfo->seqno) {
- log_warn("Scan of VG %s from %s found metadata seqno %d vs previous %d.",
- vgname, dev_name(info->dev), vgsummary->seqno, vginfo->seqno);
- vginfo->scan_summary_mismatch = 1;
- /* If we don't return success, this dev info will be removed from lvmcache,
- and then we won't be able to rescan it or repair it. */
+ log_debug_cache("lvmcache %s mda%d VG %s older seqno %u checksum %x mda_size %zu",
+ dev_name(info->dev), vgsummary->mda_num, vgname,
+ vgsummary->seqno, vgsummary->mda_checksum, vgsummary->mda_size);
return 1;
- }
- if (!vginfo->mda_size) {
+ } else if (vgsummary->seqno > vginfo->seqno) {
+ vginfo->scan_summary_mismatch = true;
+
+ /* Replace vginfo values with values from newer metadata. */
+ vginfo->seqno = vgsummary->seqno;
vginfo->mda_checksum = vgsummary->mda_checksum;
vginfo->mda_size = vgsummary->mda_size;
- log_debug_cache("lvmcache %s: VG %s: set mda_checksum to %x mda_size to %zu",
- dev_name(info->dev), vginfo->vgname,
- vginfo->mda_checksum, vginfo->mda_size);
-
- } else if ((vginfo->mda_size != vgsummary->mda_size) || (vginfo->mda_checksum != vgsummary->mda_checksum)) {
- log_warn("Scan of VG %s from %s found mda_checksum %x mda_size %zu vs previous %x %zu",
- vgname, dev_name(info->dev), vgsummary->mda_checksum, vgsummary->mda_size,
- vginfo->mda_checksum, vginfo->mda_size);
- vginfo->scan_summary_mismatch = 1;
- /* If we don't return success, this dev info will be removed from lvmcache,
- and then we won't be able to rescan it or repair it. */
+ log_debug_cache("lvmcache %s mda%d VG %s newer seqno %u checksum %x mda_size %zu",
+ dev_name(info->dev), vgsummary->mda_num, vgname,
+ vgsummary->seqno, vgsummary->mda_checksum, vgsummary->mda_size);
+
+ goto update_vginfo;
+ } else {
+ /*
+ * Same seqno as previous metadata we saw for this VG.
+ * If the metadata somehow has a different checksum or size,
+ * even though it has the same seqno, something has gone wrong.
+ * FIXME: test this case: VG has two PVs, first goes missing,
+ * second updated to seqno 4, first comes back and second goes
+ * missing, first updated to seqno 4, second comes back, now
+ * both are present with same seqno but different checksums.
+ */
+
+ if ((vginfo->mda_size != vgsummary->mda_size) || (vginfo->mda_checksum != vgsummary->mda_checksum)) {
+ log_warn("WARNING: scan of VG %s from %s mda%d found mda_checksum %x mda_size %zu vs %x %zu",
+ vgname, dev_name(info->dev), vgsummary->mda_num,
+ vgsummary->mda_checksum, vgsummary->mda_size,
+ vginfo->mda_checksum, vginfo->mda_size);
+ vginfo->scan_summary_mismatch = true;
+ return 0;
+ }
+
+ /*
+ * The seqno and checksum matches what was previously seen;
+ * the summary values have already been saved in vginfo.
+ */
return 1;
}
- /*
- * If a dev has an unmatching checksum, ignore the other
- * info from it, keeping the info we already saved.
- */
+ update_vginfo:
if (!_lvmcache_update_vgstatus(info, vgsummary->vgstatus, vgsummary->creation_host,
vgsummary->lock_type, vgsummary->system_id)) {
+ /*
+ * This shouldn't happen, it's an internal errror, and we can leave
+ * the info in place without saving the summary values in vginfo.
+ */
log_error("Failed to update VG %s info in lvmcache.", vgname);
- return 0;
}
return 1;
@@ -2325,17 +2392,17 @@ int lvmcache_vg_is_foreign(struct cmd_context *cmd, const char *vgname, const ch
* lvmcache: info for dev5 is deleted, FIXME: use a defective state
*/
-int lvmcache_scan_mismatch(struct cmd_context *cmd, const char *vgname, const char *vgid)
+bool lvmcache_scan_mismatch(struct cmd_context *cmd, const char *vgname, const char *vgid)
{
struct lvmcache_vginfo *vginfo;
if (!vgname || !vgid)
- return 1;
+ return true;
if ((vginfo = lvmcache_vginfo_from_vgid(vgid)))
return vginfo->scan_summary_mismatch;
- return 1;
+ return true;
}
static uint64_t _max_metadata_size;
@@ -2394,6 +2461,42 @@ struct metadata_area *lvmcache_get_mda(struct cmd_context *cmd,
return NULL;
}
+/*
+ * This is used by the metadata repair command to check if
+ * the metadata on a dev needs repair because it's old.
+ */
+bool lvmcache_has_old_metadata(struct cmd_context *cmd, const char *vgname, const char *vgid, struct device *dev)
+{
+ struct lvmcache_vginfo *vginfo;
+ struct lvmcache_info *info;
+
+ /* shouldn't happen */
+ if (!vgname || !vgid)
+ return false;
+
+ /* shouldn't happen */
+ if (!(vginfo = lvmcache_vginfo_from_vgid(vgid)))
+ return false;
+
+ /* shouldn't happen */
+ if (!(info = lvmcache_info_from_pvid(dev->pvid, NULL, 0)))
+ return false;
+
+ /* writing to a new PV */
+ if (!info->summary_seqno)
+ return false;
+
+ /* on same dev, one mda has newer metadata than the other */
+ if (info->summary_seqno_mismatch)
+ return true;
+
+ /* one or both mdas on this dev has older metadata than another dev */
+ if (vginfo->seqno > info->summary_seqno)
+ return true;
+
+ return false;
+}
+
void lvmcache_get_outdated_devs(struct cmd_context *cmd,
const char *vgname, const char *vgid,
struct dm_list *devs)
diff --git a/lib/cache/lvmcache.h b/lib/cache/lvmcache.h
index 0f83c80..16cbb48 100644
--- a/lib/cache/lvmcache.h
+++ b/lib/cache/lvmcache.h
@@ -57,10 +57,12 @@ struct lvmcache_vgsummary {
char *creation_host;
const char *system_id;
const char *lock_type;
+ uint32_t seqno;
uint32_t mda_checksum;
size_t mda_size;
- int zero_offset;
- int seqno;
+ int mda_num; /* 1 = summary from mda1, 2 = summary from mda2 */
+ unsigned mda_ignored:1;
+ unsigned zero_offset:1;
};
int lvmcache_init(struct cmd_context *cmd);
@@ -202,7 +204,7 @@ int lvmcache_get_vg_devs(struct cmd_context *cmd,
struct dm_list *devs);
void lvmcache_set_independent_location(const char *vgname);
-int lvmcache_scan_mismatch(struct cmd_context *cmd, const char *vgname, const char *vgid);
+bool lvmcache_scan_mismatch(struct cmd_context *cmd, const char *vgname, const char *vgid);
int lvmcache_vginfo_has_pvid(struct lvmcache_vginfo *vginfo, char *pvid);
@@ -222,6 +224,8 @@ int dev_in_device_list(struct device *dev, struct dm_list *head);
bool lvmcache_has_bad_metadata(struct device *dev);
+bool lvmcache_has_old_metadata(struct cmd_context *cmd, const char *vgname, const char *vgid, struct device *dev);
+
void lvmcache_get_outdated_devs(struct cmd_context *cmd,
const char *vgname, const char *vgid,
struct dm_list *devs);
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