On 2015-01-28 at 13:38, Denis V. Lunev wrote:
There is a possibility that we are extending our image and thus writing zeroes beyond the end of the file. In this case we do not need to care about the hole to make sure that there is no data in the file under this offset (pre-condition to fallocate(0) to work). We could simply call fallocate(0).This improves the performance of writing zeroes even on really old platforms which do not have even FALLOC_FL_PUNCH_HOLE. Before the patch do_fallocate was used when either CONFIG_FALLOCATE_PUNCH_HOLE or CONFIG_FALLOCATE_ZERO_RANGE are defined. Now the story is different. CONFIG_FALLOCATE is defined when Linux fallocate is defined, posix_fallocate is completely different story (CONFIG_POSIX_FALLOCATE). CONFIG_FALLOCATE is mandatory prerequite for both CONFIG_FALLOCATE_PUNCH_HOLE and CONFIG_FALLOCATE_ZERO_RANGE thus we are on the safe side. Signed-off-by: Denis V. Lunev <d...@openvz.org> CC: Max Reitz <mre...@redhat.com> CC: Kevin Wolf <kw...@redhat.com> CC: Stefan Hajnoczi <stefa...@redhat.com> CC: Peter Lieven <p...@kamp.de> CC: Fam Zheng <f...@redhat.com> --- block/raw-posix.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/block/raw-posix.c b/block/raw-posix.c index 2e24829..3db911a 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -147,6 +147,7 @@ typedef struct BDRVRawState { bool has_discard:1; bool has_write_zeroes:1; bool discard_zeroes:1; + bool has_fallocate; bool needs_alignment; } BDRVRawState;@@ -452,6 +453,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,} if (S_ISREG(st.st_mode)) { s->discard_zeroes = true; + s->has_fallocate = true; } if (S_ISBLK(st.st_mode)) { #ifdef BLKDISCARDZEROES @@ -902,7 +904,7 @@ static int translate_err(int err) return err; }-#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_FALLOCATE_ZERO_RANGE)+#ifdef CONFIG_FALLOCATE static int do_fallocate(int fd, int mode, off_t offset, off_t len) { do { @@ -980,6 +982,16 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb) } #endif+#ifdef CONFIG_FALLOCATE+ if (s->has_fallocate && aiocb->aio_offset >= bdrv_getlength(aiocb->bs)) { + int ret = do_fallocate(s->fd, 0, aiocb->aio_offset, aiocb->aio_nbytes); + if (ret == 0 || ret != -ENOTSUP) { + return ret; + } + s->has_fallocate = false; + } +#endif + return -ENOTSUP; }
Now that you do have has_fallocate, I think you should be using it in patch 5 as well. So I think you should either you make this patch add it in the area touched by patch 5, or you introduce has_fallocate in patch 5 already and use it there.
Max
