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lvm2/lib/format_text/import.c
David Teigland a7cb76ae94 scan: use bcache for label scan and vg read
New label_scan function populates bcache for each device
on the system.

The two read paths are updated to get data from bcache.

The bcache is not yet used for writing.  bcache blocks
for a device are invalidated when the device is written.
2018-04-20 11:19:24 -05:00

255 lines
6.6 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "lib.h"
#include "metadata.h"
#include "import-export.h"
/* FIXME Use tidier inclusion method */
static struct text_vg_version_ops *(_text_vsn_list[2]);
static int _text_import_initialised = 0;
static void _init_text_import(void)
{
if (_text_import_initialised)
return;
_text_vsn_list[0] = text_vg_vsn1_init();
_text_vsn_list[1] = NULL;
_text_import_initialised = 1;
}
/*
* Find out vgname on a given device.
*/
int text_read_metadata_summary(const struct format_type *fmt,
struct device *dev, dev_io_reason_t reason,
off_t offset, uint32_t size,
off_t offset2, uint32_t size2,
checksum_fn_t checksum_fn,
int checksum_only,
struct lvmcache_vgsummary *vgsummary)
{
struct dm_config_tree *cft;
struct text_vg_version_ops **vsn;
int r = 0;
_init_text_import();
if (!(cft = config_open(CONFIG_FILE_SPECIAL, NULL, 0)))
return_0;
if (dev) {
log_debug_metadata("Reading metadata summary from %s at %llu size %d (+%d)",
dev_name(dev), (unsigned long long)offset,
size, size2);
if (!config_file_read_fd(cft, dev, reason, offset, size,
offset2, size2, checksum_fn,
vgsummary->mda_checksum,
checksum_only, 1)) {
/* FIXME: handle errors */
log_error("Couldn't read volume group metadata from %s.", dev_name(dev));
goto out;
}
} else {
if (!config_file_read(cft)) {
log_error("Couldn't read volume group metadata from file.");
goto out;
}
}
if (checksum_only) {
/* Checksum matches already-cached content - no need to reparse. */
log_debug_metadata("Skipped parsing metadata on %s", dev_name(dev));
r = 1;
goto out;
}
/*
* Find a set of version functions that can read this file
*/
for (vsn = &_text_vsn_list[0]; *vsn; vsn++) {
if (!(*vsn)->check_version(cft))
continue;
if (!(*vsn)->read_vgsummary(fmt, cft, vgsummary))
goto_out;
r = 1;
break;
}
out:
config_destroy(cft);
return r;
}
struct cached_vg_fmtdata {
uint32_t cached_mda_checksum;
size_t cached_mda_size;
};
struct volume_group *text_read_metadata(struct format_instance *fid,
const char *file,
struct cached_vg_fmtdata **vg_fmtdata,
unsigned *use_previous_vg,
struct device *dev, int primary_mda,
off_t offset, uint32_t size,
off_t offset2, uint32_t size2,
checksum_fn_t checksum_fn,
uint32_t checksum,
time_t *when, char **desc)
{
struct volume_group *vg = NULL;
struct dm_config_tree *cft;
struct text_vg_version_ops **vsn;
int skip_parse;
/*
* This struct holds the checksum and size of the VG metadata
* that was read from a previous device. When we read the VG
* metadata from this device, we can skip parsing it into a
* cft (saving time) if the checksum of the metadata buffer
* we read from this device matches the size/checksum saved in
* the mda_header/rlocn struct on this device, and matches the
* size/checksum from the previous device.
*/
if (vg_fmtdata && !*vg_fmtdata &&
!(*vg_fmtdata = dm_pool_zalloc(fid->mem, sizeof(**vg_fmtdata)))) {
log_error("Failed to allocate VG fmtdata for text format.");
return NULL;
}
_init_text_import();
*desc = NULL;
*when = 0;
if (!(cft = config_open(CONFIG_FILE_SPECIAL, file, 0)))
return_NULL;
/* Does the metadata match the already-cached VG? */
skip_parse = vg_fmtdata &&
((*vg_fmtdata)->cached_mda_checksum == checksum) &&
((*vg_fmtdata)->cached_mda_size == (size + size2));
if (dev) {
log_debug_metadata("Reading metadata from %s at %llu size %d (+%d)",
dev_name(dev), (unsigned long long)offset,
size, size2);
if (!config_file_read_fd(cft, dev, MDA_CONTENT_REASON(primary_mda), offset, size,
offset2, size2, checksum_fn, checksum,
skip_parse, 1)) {
/* FIXME: handle errors */
log_error("Couldn't read volume group metadata from %s.", dev_name(dev));
goto out;
}
} else {
if (!config_file_read(cft)) {
log_error("Couldn't read volume group metadata from file.");
goto out;
}
}
if (skip_parse) {
if (use_previous_vg)
*use_previous_vg = 1;
log_debug_metadata("Skipped parsing metadata on %s", dev_name(dev));
goto out;
}
/*
* Find a set of version functions that can read this file
*/
for (vsn = &_text_vsn_list[0]; *vsn; vsn++) {
if (!(*vsn)->check_version(cft))
continue;
if (!(vg = (*vsn)->read_vg(fid, cft, 0)))
goto_out;
(*vsn)->read_desc(vg->vgmem, cft, when, desc);
break;
}
if (vg && vg_fmtdata && *vg_fmtdata) {
(*vg_fmtdata)->cached_mda_size = (size + size2);
(*vg_fmtdata)->cached_mda_checksum = checksum;
}
if (use_previous_vg)
*use_previous_vg = 0;
out:
config_destroy(cft);
return vg;
}
struct volume_group *text_read_metadata_file(struct format_instance *fid,
const char *file,
time_t *when, char **desc)
{
return text_read_metadata(fid, file, NULL, NULL, NULL, 0,
(off_t)0, 0, (off_t)0, 0, NULL, 0,
when, desc);
}
static struct volume_group *_import_vg_from_config_tree(const struct dm_config_tree *cft,
struct format_instance *fid,
unsigned allow_lvmetad_extensions)
{
struct volume_group *vg = NULL;
struct text_vg_version_ops **vsn;
int vg_missing;
_init_text_import();
for (vsn = &_text_vsn_list[0]; *vsn; vsn++) {
if (!(*vsn)->check_version(cft))
continue;
/*
* The only path to this point uses cached vgmetadata,
* so it can use cached PV state too.
*/
if (!(vg = (*vsn)->read_vg(fid, cft, allow_lvmetad_extensions)))
stack;
else if ((vg_missing = vg_missing_pv_count(vg))) {
log_verbose("There are %d physical volumes missing.",
vg_missing);
vg_mark_partial_lvs(vg, 1);
/* FIXME: move this code inside read_vg() */
}
break;
}
return vg;
}
struct volume_group *import_vg_from_config_tree(const struct dm_config_tree *cft,
struct format_instance *fid)
{
return _import_vg_from_config_tree(cft, fid, 0);
}
struct volume_group *import_vg_from_lvmetad_config_tree(const struct dm_config_tree *cft,
struct format_instance *fid)
{
return _import_vg_from_config_tree(cft, fid, 1);
}