thin-provisioning-tools/thin-provisioning/file_utils.cc

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#include "persistent-data/math_utils.h"
#include "thin-provisioning/file_utils.h"
#include <linux/fs.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
using namespace base;
//----------------------------------------------------------------
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persistent_data::block_address
thin_provisioning::get_nr_blocks(string const &path)
{
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using namespace persistent_data;
struct stat info;
block_address nr_blocks;
int r = ::stat(path.c_str(), &info);
if (r)
throw runtime_error("Couldn't stat dev path");
if (S_ISREG(info.st_mode) && info.st_size)
nr_blocks = div_up<block_address>(info.st_size, MD_BLOCK_SIZE);
else if (S_ISBLK(info.st_mode)) {
// To get the size of a block device we need to
// open it, and then make an ioctl call.
int fd = ::open(path.c_str(), O_RDONLY);
if (fd < 0)
throw runtime_error("couldn't open block device to ascertain size");
r = ::ioctl(fd, BLKGETSIZE64, &nr_blocks);
if (r) {
::close(fd);
throw runtime_error("ioctl BLKGETSIZE64 failed");
}
::close(fd);
nr_blocks = div_down<block_address>(nr_blocks, MD_BLOCK_SIZE);
} else
// FIXME: needs a better message
throw runtime_error("bad path");
return nr_blocks;
}
//----------------------------------------------------------------