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lvm2/lib/filters/filter-signature.c
David Teigland 57bb46c5e7 filter: use bcache for filter reads
Filters are still applied before any device reading or
the label scan, but any filter checks that want to read
the device are skipped and the device is flagged.

After bcache is populated, but before lvm looks for
devices (i.e. before label scan), the filters are
reapplied to the devices that were flagged above.
The filters will then find the data they need in
bcache.
2018-05-10 16:03:19 -05:00

97 lines
2.0 KiB
C

/*
* Copyright (C) 2004 Luca Berra
* Copyright (C) 2004-2006 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 "filter.h"
#ifdef __linux__
#define BUFSIZE 4096
static int _ignore_signature(struct dev_filter *f __attribute__((unused)),
struct device *dev)
{
char buf[BUFSIZE];
int ret = 0;
if (!scan_bcache) {
/* let pass, call again after scan */
log_debug_devs("filter signature deferred %s", dev_name(dev));
dev->flags |= DEV_FILTER_AFTER_SCAN;
return 1;
}
memset(buf, 0, BUFSIZE);
if (!dev_read_bytes(dev, 0, BUFSIZE, buf)) {
log_debug_devs("%s: Skipping: error in signature detection",
dev_name(dev));
ret = 0;
goto out;
}
if (dev_is_lvm1(dev, buf, BUFSIZE)) {
log_debug_devs("%s: Skipping lvm1 device", dev_name(dev));
ret = 0;
goto out;
}
if (dev_is_pool(dev, buf, BUFSIZE)) {
log_debug_devs("%s: Skipping gfs-pool device", dev_name(dev));
ret = 0;
goto out;
}
ret = 1;
out:
return ret;
}
static void _destroy(struct dev_filter *f)
{
if (f->use_count)
log_error(INTERNAL_ERROR "Destroying signature filter while in use %u times.", f->use_count);
dm_free(f);
}
struct dev_filter *signature_filter_create(struct dev_types *dt)
{
struct dev_filter *f;
if (!(f = dm_zalloc(sizeof(*f)))) {
log_error("md filter allocation failed");
return NULL;
}
f->passes_filter = _ignore_signature;
f->destroy = _destroy;
f->use_count = 0;
f->private = dt;
log_debug_devs("signature filter initialised.");
return f;
}
#else
struct dev_filter *signature_filter_create(struct dev_types *dt)
{
return NULL;
}
#endif