[linux-lvm] HOWTO: create a thick logical snapshot from C

[Tomas Dalebjörk]

Hi,

I want to create the snapshot like this command, but from C.

lvcreate -s -c 512k -n snap -L 1G testvg/lvol1

Just to try; I compiled this program, but it can't resolve the references
-------
#include "lvm2app.h"

int snaplv(char *vgname, char *lvname)
{
        int rc;
        lvm_t handle;
        vg_t vg;
        lv_t lv;
        lv_t lvsnap;
        char msg[200];
        char *snap_name="snap";
        struct lvm_lv_create_params *lvcp = NULL;
        uint64_t max_snap_size = 1*1024*1024*1024;

        handle = lvm_init(NULL);

        if(!handle)
                return -1;

        vg = lvm_vg_open(handle, vgname, "r", 0);
        if(!vg && lvm_errno(handle))
        {
                lvm_quit(handle);
                return -1;
        }

        lv = lvm_lv_from_name(vg, lvname);
        if(!lv)
        {
                lvm_vg_close(vg);
                lvm_quit(handle);

                return -1;
        }

        lvsnap = lvm_lv_snapshot(lv, strdup(snap_name), max_snap_size);
        lvm_vg_close(vg);
        lvm_quit(handle);

        return 0;
}

void main(void)
{
        snaplv("testvg","test");
}
--------------------------------
Compiling gives error

[root at centos64 ~]# gcc -llvm2app snaplv.c
snaplv.c: In function ‘snaplv’:
snaplv.c:36: warning: assignment makes pointer from integer without a cast
/tmp/ccvgg1K0.o: In function `snaplv':
snaplv.c:(.text+0x105): undefined reference to `lvm_lv_snapshot'
collect2: ld returned 1 exit status
[root at centos64 ~]#

-----------------------------

Can anyone share an idea how to do this from C; without using system()

Regards Tomas
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