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scan: add simple scan to find a pvid

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This commit is contained in:
David Teigland 2019-10-30 15:11:57 -05:00
parent 74ad2cd76f
commit 94076245df
2 changed files with 72 additions and 0 deletions
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70
lib/label/label.c
View File

@ -24,6 +24,8 @@
#include "lib/activate/activate.h"
#include "lib/label/hints.h"
#include "lib/metadata/metadata.h"
#include "lib/format_text/format-text.h"
#include "lib/format_text/layout.h"
#include <sys/stat.h>
#include <fcntl.h>
@ -919,6 +921,74 @@ static void _prepare_open_file_limit(struct cmd_context *cmd, unsigned int num_d
#endif
}
int label_scan_for_pvid(struct cmd_context *cmd, char *pvid, struct device **dev_out)
{
char buf[LABEL_SIZE] __attribute__((aligned(8)));
struct dm_list devs;
struct dev_iter *iter;
struct device_list *devl, *devl2;
struct device *dev;
struct pv_header *pvh;
int ret = 0;
dm_list_init(&devs);
dev_cache_scan();
if (!(iter = dev_iter_create(cmd->filter, 0))) {
log_error("Scanning failed to get devices.");
return 0;
}
log_debug_devs("Filtering devices to scan");
while ((dev = dev_iter_get(cmd, iter))) {
if (!(devl = zalloc(sizeof(*devl))))
continue;
devl->dev = dev;
dm_list_add(&devs, &devl->list);
};
dev_iter_destroy(iter);
if (!scan_bcache) {
if (!_setup_bcache())
goto_out;
}
log_debug_devs("Reading labels for pvid");
dm_list_iterate_items(devl, &devs) {
dev = devl->dev;
memset(buf, 0, sizeof(buf));
if (!label_scan_open(dev))
continue;
if (!dev_read_bytes(dev, 512, LABEL_SIZE, buf)) {
_scan_dev_close(dev);
goto out;
}
pvh = (struct pv_header *)(buf + 32);
if (!memcmp(pvh->pv_uuid, pvid, ID_LEN)) {
*dev_out = devl->dev;
_scan_dev_close(dev);
break;
}
_scan_dev_close(dev);
}
ret = 1;
out:
dm_list_iterate_items_safe(devl, devl2, &devs) {
dm_list_del(&devl->list);
free(devl);
}
return ret;
}
/*
* Scan devices on the system to discover which are LVM devices.
* Info about the LVM devices (PVs) is saved in lvmcache in a

2
lib/label/label.h
View File

@ -118,6 +118,8 @@ int label_scan_open(struct device *dev);
int label_scan_open_excl(struct device *dev);
int label_scan_open_rw(struct device *dev);
int label_scan_for_pvid(struct cmd_context *cmd, char *pvid, struct device **dev_out);
/*
* Wrappers around bcache equivalents.
* (these make it easier to disable bcache and revert to direct rw if needed)