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

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#include "persistent-data/math_utils.h"
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#include "persistent-data/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;
using namespace bcache;
using namespace persistent_data;
//----------------------------------------------------------------
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persistent_data::block_address
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persistent_data::get_nr_blocks(string const &path, sector_t block_size)
{
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using namespace persistent_data;
struct stat info;
block_address nr_blocks;
int r = ::stat(path.c_str(), &info);
if (r) {
ostringstream out;
out << "Couldn't stat dev path '" << path << "': "
<< strerror(errno);
throw runtime_error(out.str());
}
if (S_ISREG(info.st_mode) && info.st_size)
nr_blocks = div_down<block_address>(info.st_size, 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);
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nr_blocks = div_down<block_address>(nr_blocks, block_size);
} else
// FIXME: needs a better message
throw runtime_error("bad path");
return nr_blocks;
}
block_address
persistent_data::get_nr_metadata_blocks(string const &path)
{
return get_nr_blocks(path, MD_BLOCK_SIZE);
}
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persistent_data::block_manager<>::ptr
persistent_data::open_bm(std::string const &dev_path, block_manager<>::mode m, bool excl)
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{
block_address nr_blocks = get_nr_metadata_blocks(dev_path);
return block_manager<>::ptr(new block_manager<>(dev_path, nr_blocks, 1, m, excl));
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}
void
persistent_data::check_file_exists(string const &file) {
struct stat info;
int r = ::stat(file.c_str(), &info);
if (r)
throw runtime_error("Couldn't stat file");
if (!S_ISREG(info.st_mode))
throw runtime_error("Not a regular file");
}
//----------------------------------------------------------------