[lvm-devel] master - pvck: new dump option to extract metadata
David Teigland
teigland at sourceware.org
Thu May 23 16:50:43 UTC 2019
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=52586b1039a0c1d273676416ba074cadde308bc4
Commit: 52586b1039a0c1d273676416ba074cadde308bc4
Parent: 1022b88a66dd02e981e738719e17452cd5c1bd59
Author: David Teigland <teigland at redhat.com>
AuthorDate: Wed May 22 14:25:08 2019 -0500
Committer: David Teigland <teigland at redhat.com>
CommitterDate: Thu May 23 11:49:06 2019 -0500
pvck: new dump option to extract metadata
The new command 'pvck --dump metadata PV' will extract
the current version of VG metadata from a PV for testing
and debugging. --dump metadata_area extracts the entire
text metadata area.
---
lib/cache/lvmcache.c | 31 ++++++
lib/cache/lvmcache.h | 5 +
lib/format_text/format-text.c | 218 +++++++++++++++++++++++++++++++++++++++++
lib/format_text/format-text.h | 14 +++
man/pvck.8_des | 9 ++-
tools/args.h | 5 +
tools/command-lines.in | 6 +
tools/commands.h | 2 +-
tools/pvck.c | 99 ++++++++++++++++++-
9 files changed, 386 insertions(+), 3 deletions(-)
diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index 7d0c60d..a4037a5 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -2301,3 +2301,34 @@ int lvmcache_vginfo_has_pvid(struct lvmcache_vginfo *vginfo, char *pvid)
}
return 0;
}
+
+struct metadata_area *lvmcache_get_mda(struct cmd_context *cmd,
+ const char *vgname,
+ struct device *dev,
+ int use_mda_num)
+{
+ struct lvmcache_vginfo *vginfo;
+ struct lvmcache_info *info;
+ struct metadata_area *mda;
+
+ if (!use_mda_num)
+ use_mda_num = 1;
+
+ if (!(vginfo = lvmcache_vginfo_from_vgname(vgname, NULL)))
+ return NULL;
+
+ dm_list_iterate_items(info, &vginfo->infos) {
+ if (info->dev != dev)
+ continue;
+
+ dm_list_iterate_items(mda, &info->mdas) {
+ if ((use_mda_num == 1) && (mda->status & MDA_PRIMARY))
+ return mda;
+ if ((use_mda_num == 2) && !(mda->status & MDA_PRIMARY))
+ return mda;
+ }
+ return NULL;
+ }
+ return NULL;
+}
+
diff --git a/lib/cache/lvmcache.h b/lib/cache/lvmcache.h
index 26e0953..5e59b94 100644
--- a/lib/cache/lvmcache.h
+++ b/lib/cache/lvmcache.h
@@ -168,6 +168,11 @@ unsigned lvmcache_mda_count(struct lvmcache_info *info);
int lvmcache_vgid_is_cached(const char *vgid);
uint64_t lvmcache_smallest_mda_size(struct lvmcache_info *info);
+struct metadata_area *lvmcache_get_mda(struct cmd_context *cmd,
+ const char *vgname,
+ struct device *dev,
+ int use_mda_num);
+
int lvmcache_found_duplicate_pvs(void);
int lvmcache_found_duplicate_vgnames(void);
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index 3828d5f..abf8afc 100644
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -2602,3 +2602,221 @@ bad:
return NULL;
}
+
+static char *_read_metadata_text(struct cmd_context *cmd, struct device *dev,
+ uint64_t area_start, uint64_t area_size,
+ uint32_t *len, uint64_t *disk_offset)
+{
+ struct mda_header *mh;
+ struct raw_locn *rlocn_slot0;
+ uint64_t text_offset, text_size;
+ char *area_buf;
+ char *text_buf;
+
+ /*
+ * Read the entire metadata area, including mda_header and entire
+ * circular buffer.
+ */
+ if (!(area_buf = malloc(area_size)))
+ return_NULL;
+
+ if (!dev_read_bytes(dev, area_start, area_size, area_buf)) {
+ log_error("Failed to read device %s at %llu size %llu",
+ dev_name(dev),
+ (unsigned long long)area_start,
+ (unsigned long long)area_size);
+ return NULL;
+ }
+
+ mh = (struct mda_header *)area_buf;
+ _xlate_mdah(mh);
+
+ rlocn_slot0 = &mh->raw_locns[0];
+ text_offset = rlocn_slot0->offset;
+ text_size = rlocn_slot0->size;
+
+ /*
+ * Copy and return the current metadata text out of the metadata area.
+ */
+
+ if (!(text_buf = malloc(text_size)))
+ return_NULL;
+
+ memcpy(text_buf, area_buf + text_offset, text_size);
+
+ if (len)
+ *len = (uint32_t)text_size;
+ if (disk_offset)
+ *disk_offset = area_start + text_offset;
+
+ free(area_buf);
+
+ return text_buf;
+}
+
+int dump_metadata_text(struct cmd_context *cmd,
+ const char *vgname,
+ const char *vgid,
+ struct device *dev,
+ struct metadata_area *mda,
+ const char *tofile)
+{
+ char *textbuf;
+ struct format_instance *fid;
+ struct format_instance_ctx fic;
+ struct mda_context *mdac;
+ struct volume_group *vg;
+ unsigned use_previous_vg = 0;
+ uint32_t textlen = 0;
+ uint32_t textcrc;
+ uint64_t text_disk_offset;
+ int ret = 0;
+
+ /*
+ * Set up overhead/abstractions for reading a given vgname
+ * (fmt/fid/fic/vgid).
+ */
+
+ fic.type = FMT_INSTANCE_MDAS | FMT_INSTANCE_AUX_MDAS;
+ fic.context.vg_ref.vg_name = vgname;
+ fic.context.vg_ref.vg_id = vgid;
+
+ if (!(fid = _text_create_text_instance(cmd->fmt, &fic))) {
+ log_error("Failed to create format instance");
+ return 0;
+ }
+
+ mdac = mda->metadata_locn;
+
+ /*
+ * Read the VG metadata from the device as a raw chunk of original text.
+ */
+ textbuf = _read_metadata_text(cmd, dev,
+ mdac->area.start, mdac->area.size,
+ &textlen, &text_disk_offset);
+ if (!textbuf || !textlen) {
+ log_error("No metadata text found on %s", dev_name(dev));
+ _text_destroy_instance(fid);
+ return 0;
+ }
+
+ textcrc = calc_crc(INITIAL_CRC, (uint8_t *)textbuf, textlen);
+
+ /*
+ * Read the same VG metadata, but imported/parsed into a vg struct
+ * format so we know it's valid/parsable, and can look at values in it.
+ */
+ if (!(vg = _vg_read_raw(fid, vgname, mda, NULL, &use_previous_vg))) {
+ log_warn("WARNING: parse error for metadata on %s.", dev_name(dev));
+ _text_destroy_instance(fid);
+ }
+
+ log_print("Metadata for %s from %s at %llu size %u with seqno %u checksum 0x%x.",
+ vgname, dev_name(dev),
+ (unsigned long long)text_disk_offset, textlen,
+ vg ? vg->seqno : 0, textcrc);
+
+ if (!tofile) {
+ log_print("---");
+ printf("%s\n", textbuf);
+ log_print("---");
+ } else {
+ FILE *fp;
+ if (!(fp = fopen(tofile, "wx"))) {
+ log_error("Failed to create file %s", tofile);
+ goto out;
+ }
+
+ fprintf(fp, "%s", textbuf);
+
+ if (fflush(fp))
+ stack;
+ if (fclose(fp))
+ stack;
+ }
+
+ if (vg)
+ release_vg(vg);
+
+ free(textbuf);
+ ret = 1;
+out:
+ return ret;
+}
+
+static char *_read_metadata_area(struct cmd_context *cmd, struct device *dev,
+ uint64_t area_start, uint64_t area_size)
+{
+ char *area_buf;
+
+ /*
+ * Read the entire metadata area, including mda_header and entire
+ * circular buffer.
+ */
+ if (!(area_buf = malloc(area_size)))
+ return_NULL;
+
+ if (!dev_read_bytes(dev, area_start, area_size, area_buf)) {
+ log_error("Failed to read device %s at %llu size %llu",
+ dev_name(dev),
+ (unsigned long long)area_start,
+ (unsigned long long)area_size);
+ return NULL;
+ }
+
+ return area_buf;
+}
+
+int dump_metadata_area(struct cmd_context *cmd,
+ const char *vgname,
+ const char *vgid,
+ struct device *dev,
+ struct metadata_area *mda,
+ const char *tofile)
+{
+ char *areabuf;
+ char *textbuf;
+ struct mda_context *mdac;
+ int ret = 0;
+
+ mdac = mda->metadata_locn;
+
+ areabuf = _read_metadata_area(cmd, dev,
+ mdac->area.start, mdac->area.size);
+ if (!areabuf) {
+ log_error("No metadata area found on %s", dev_name(dev));
+ return 0;
+ }
+
+ log_print("Metadata buffer for %s from %s in area at %llu size %llu offset 512.",
+ vgname, dev_name(dev),
+ (unsigned long long)mdac->area.start,
+ (unsigned long long)mdac->area.size);
+
+ /* text starts after mda_header which uses 512 bytes */
+ textbuf = areabuf + 512;
+
+ if (!tofile) {
+ /* N.B. this will often include unprintable data */
+ log_print("---");
+ fwrite(textbuf, mdac->area.size - 512, 1, stdout);
+ log_print("---");
+ } else {
+ FILE *fp;
+ if (!(fp = fopen(tofile, "wx"))) {
+ log_error("Failed to create file %s", tofile);
+ goto out;
+ }
+
+ fwrite(textbuf, mdac->area.size - 512, 1, fp);
+
+ if (fflush(fp))
+ stack;
+ if (fclose(fp))
+ stack;
+ }
+ ret = 1;
+out:
+ free(areabuf);
+ return ret;
+}
diff --git a/lib/format_text/format-text.h b/lib/format_text/format-text.h
index 1300e58..6be237b 100644
--- a/lib/format_text/format-text.h
+++ b/lib/format_text/format-text.h
@@ -76,4 +76,18 @@ struct data_area_list {
struct disk_locn disk_locn;
};
+int dump_metadata_text(struct cmd_context *cmd,
+ const char *vgname,
+ const char *vgid,
+ struct device *dev,
+ struct metadata_area *mda,
+ const char *tofile);
+
+int dump_metadata_area(struct cmd_context *cmd,
+ const char *vgname,
+ const char *vgid,
+ struct device *dev,
+ struct metadata_area *mda,
+ const char *tofile);
+
#endif
diff --git a/man/pvck.8_des b/man/pvck.8_des
index 0a32657..fb826d3 100644
--- a/man/pvck.8_des
+++ b/man/pvck.8_des
@@ -1 +1,8 @@
-pvck checks the LVM metadata for consistency on PVs.
+pvck checks LVM metadata on PVs.
+
+Use the --dump option to extract metadata from PVs for debugging.
+With dump, set --pvmetadatacopies 2 to extract metadata from a
+second metadata area at the end of the device. Use the --file
+option to save the raw metadata to a specified file. (The raw
+metadata is not usable with vgcfgbackup and vgcfgrestore.)
+
diff --git a/tools/args.h b/tools/args.h
index 3d72e8a..c1efdd6 100644
--- a/tools/args.h
+++ b/tools/args.h
@@ -213,6 +213,11 @@ arg(driverloaded_ARG, '\0', "driverloaded", bool_VAL, 0, 0,
"If set to no, the command will not attempt to use device-mapper.\n"
"For testing and debugging.\n")
+arg(dump_ARG, '\0', "dump", string_VAL, 0, 0,
+ "Dump metadata from a PV. Option values include \\fBmetadata\\fP\n"
+ "to extract the current text metadata, and \\fBmetadata_area\\fP\n"
+ "to extract the entire text metadata area.\n")
+
arg(errorwhenfull_ARG, '\0', "errorwhenfull", bool_VAL, 0, 0,
"Specifies thin pool behavior when data space is exhausted.\n"
"When yes, device-mapper will immediately return an error\n"
diff --git a/tools/command-lines.in b/tools/command-lines.in
index 0de3de7..0d97348 100644
--- a/tools/command-lines.in
+++ b/tools/command-lines.in
@@ -1427,6 +1427,12 @@ ID: pvresize_general
pvck PV ...
OO: --labelsector Number
ID: pvck_general
+DESC: Check for metadata on a device
+
+pvck --dump String PV
+OO: --file String, --pvmetadatacopies MetadataCopiesPV
+ID: pvck_dumpmetadata
+DESC: Dump raw metadata from a device
---
diff --git a/tools/commands.h b/tools/commands.h
index 83e50e7..612182b 100644
--- a/tools/commands.h
+++ b/tools/commands.h
@@ -114,7 +114,7 @@ xx(pvresize,
0)
xx(pvck,
- "Check the consistency of physical volume(s)",
+ "Check metadata on physical volumes",
LOCKD_VG_SH)
xx(pvcreate,
diff --git a/tools/pvck.c b/tools/pvck.c
index ce74036..15c7e6d 100644
--- a/tools/pvck.c
+++ b/tools/pvck.c
@@ -15,17 +15,115 @@
#include "base/memory/zalloc.h"
#include "tools.h"
+#include "lib/format_text/format-text.h"
+
+/*
+ * TODO: option to dump all copies of metadata that are found
+ *
+ * TODO: option to intelligently search for mda locations on
+ * disk in case the pv_header and/or mda_header are damaged.
+ */
+
+static int _dump_metadata(struct cmd_context *cmd, int argc, char **argv, int full_area)
+{
+ struct dm_list devs;
+ struct device_list *devl;
+ struct device *dev;
+ const char *pv_name;
+ const char *vgname;
+ const char *vgid;
+ struct lvmcache_info *info;
+ struct metadata_area *mda;
+ const char *tofile = NULL;
+ int mda_num = 1;
+ int ret;
+
+ dm_list_init(&devs);
+
+ if (arg_is_set(cmd, file_ARG)) {
+ if (!(tofile = arg_str_value(cmd, file_ARG, NULL)))
+ return ECMD_FAILED;
+ }
+
+ /* 1: dump metadata from first mda, 2: dump metadata from second mda */
+ if (arg_is_set(cmd, pvmetadatacopies_ARG))
+ mda_num = arg_int_value(cmd, pvmetadatacopies_ARG, 1);
+
+ pv_name = argv[0];
+
+ if (!(dev = dev_cache_get(cmd, pv_name, cmd->filter))) {
+ log_error("No device found for %s %s.", pv_name, dev_cache_filtered_reason(pv_name));
+ return ECMD_FAILED;
+ }
+
+ if (!(devl = zalloc(sizeof(*devl))))
+ return ECMD_FAILED;
+
+ devl->dev = dev;
+ dm_list_add(&devs, &devl->list);
+
+ label_scan_setup_bcache();
+ label_scan_devs(cmd, cmd->filter, &devs);
+
+ if (!dev->pvid[0]) {
+ log_error("No PV ID found for %s", dev_name(dev));
+ return ECMD_FAILED;
+ }
+
+ if (!(info = lvmcache_info_from_pvid(dev->pvid, dev, 0))) {
+ log_error("No VG info found for %s", dev_name(dev));
+ return ECMD_FAILED;
+ }
+
+ if (!(vgname = lvmcache_vgname_from_info(info))) {
+ log_error("No VG name found for %s", dev_name(dev));
+ return ECMD_FAILED;
+ }
+
+ if (!(vgid = lvmcache_vgid_from_vgname(cmd, vgname))) {
+ log_error("No VG ID found for %s", dev_name(dev));
+ return ECMD_FAILED;
+ }
+
+ if (!(mda = lvmcache_get_mda(cmd, vgname, dev, mda_num))) {
+ log_error("No mda %d found for %s", mda_num, dev_name(dev));
+ return ECMD_FAILED;
+ }
+
+ if (full_area)
+ ret = dump_metadata_area(cmd, vgname, vgid, dev, mda, tofile);
+ else
+ ret = dump_metadata_text(cmd, vgname, vgid, dev, mda, tofile);
+
+ if (!ret)
+ return ECMD_FAILED;
+ return ECMD_PROCESSED;
+}
int pvck(struct cmd_context *cmd, int argc, char **argv)
{
struct dm_list devs;
struct device_list *devl;
struct device *dev;
+ const char *dump;
const char *pv_name;
uint64_t labelsector;
int i;
int ret_max = ECMD_PROCESSED;
+ if (arg_is_set(cmd, dump_ARG)) {
+ dump = arg_str_value(cmd, dump_ARG, NULL);
+
+ if (!strcmp(dump, "metadata"))
+ return _dump_metadata(cmd, argc, argv, 0);
+
+ if (!strcmp(dump, "metadata_area"))
+ return _dump_metadata(cmd, argc, argv, 1);
+
+ log_error("Unknown dump value.");
+ return ECMD_FAILED;
+ }
+
labelsector = arg_uint64_value(cmd, labelsector_ARG, UINT64_C(0));
dm_list_init(&devs);
@@ -53,7 +151,6 @@ int pvck(struct cmd_context *cmd, int argc, char **argv)
label_scan_devs(cmd, cmd->filter, &devs);
dm_list_iterate_items(devl, &devs) {
-
/*
* The scan above will populate lvmcache with any info from the
* standard locations at the start of the device. Now populate
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