[Libguestfs] [PATCH 1/2] Preallocate output file

--- pxzcat.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/pxzcat.c b/pxzcat.c index 4ab8689..9bcdc36 100644 --- a/pxzcat.c +++ b/pxzcat.c @@ -29,10 +29,11 @@ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ +#define _GNU_SOURCE #include <config.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -166,12 +167,12 @@ xzfile_uncompress (const char *filename, const char *outputfile, debug ("uncompressed size = %" PRIu64 " bytes", size); ofd = open (outputfile, O_WRONLY|O_CREAT|O_TRUNC|O_NOCTTY, 0644); if (ofd == -1) error (EXIT_FAILURE, errno, "open: %s", outputfile); - if (ftruncate (ofd, size) == -1) - error (EXIT_FAILURE, errno, "ftruncate: %s", outputfile); + if (fallocate (ofd, 0, 0, size) == -1) + error (EXIT_FAILURE, errno, "fallocate: %s", outputfile); /* Tell the kernel we won't read the output file. */ posix_fadvise (fd, 0, 0, POSIX_FADV_RANDOM|POSIX_FADV_DONTNEED); /* Iterate over blocks. */ -- 1.8.4.1.563.g8e6fc32