diff mbox

[8/8] block/raw-posix: set max_write_zeroes to INT_MAX for regular files

Message ID 1419931250-19259-9-git-send-email-den@openvz.org
State New
Headers show

Commit Message

Denis V. Lunev Dec. 30, 2014, 9:20 a.m. UTC
fallocate() works fine and could handle properly with arbitrary size
requests. There is no sense to reduce the amount of space to fallocate.
The bigger the size, the better is performance as the amount of journal
updates is reduced.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Peter Lieven <pl@kamp.de>
---
 block/raw-posix.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
diff mbox

Patch

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 57b94ad..3e156c4 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -292,6 +292,20 @@  static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp)
     }
 }
 
+static void raw_probe_max_write_zeroes(BlockDriverState *bs)
+{
+    BDRVRawState *s = bs->opaque;
+    struct stat st;
+
+    if (fstat(s->fd, &st) < 0) {
+        return; /* no problem, keep default value */
+    }
+    if (!S_ISREG(st.st_mode) || !s->discard_zeroes) {
+        return;
+    }
+    bs->bl.max_write_zeroes = INT_MAX;
+}
+
 static void raw_parse_flags(int bdrv_flags, int *open_flags)
 {
     assert(open_flags != NULL);
@@ -598,6 +612,7 @@  static int raw_reopen_prepare(BDRVReopenState *state,
     /* Fail already reopen_prepare() if we can't get a working O_DIRECT
      * alignment with the new fd. */
     if (raw_s->fd != -1) {
+        raw_probe_max_write_zeroes(state->bs);
         raw_probe_alignment(state->bs, raw_s->fd, &local_err);
         if (local_err) {
             qemu_close(raw_s->fd);
@@ -651,6 +666,8 @@  static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 
     raw_probe_alignment(bs, s->fd, errp);
     bs->bl.opt_mem_alignment = s->buf_align;
+
+    raw_probe_max_write_zeroes(bs);
 }
 
 static ssize_t handle_aiocb_ioctl(RawPosixAIOData *aiocb)