* [Qemu-devel] [PATCH] raw-posix: Support discard on more filesystems
@ 2013-01-05 12:05 Kusanagi Kouichi
2013-01-07 13:54 ` Stefan Hajnoczi
2013-01-09 11:02 ` Paolo Bonzini
0 siblings, 2 replies; 3+ messages in thread
From: Kusanagi Kouichi @ 2013-01-05 12:05 UTC (permalink / raw)
To: qemu-devel; +Cc: Kevin Wolf, Stefan Hajnoczi
Linux 2.6.38 introduced the filesystem independent interface to
deallocate part of a file. As of Linux 3.7, btrfs, ext4, ocfs2,
tmpfs and xfs support it.
Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
---
block/raw-posix.c | 22 ++++++++++++++++++++--
configure | 19 +++++++++++++++++++
2 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 87d888e..66ba0b5 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -59,6 +59,9 @@
#ifdef CONFIG_FIEMAP
#include <linux/fiemap.h>
#endif
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+#include <linux/falloc.h>
+#endif
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <sys/disk.h>
#include <sys/cdio.h>
@@ -1098,15 +1101,30 @@ static int xfs_discard(BDRVRawState *s, int64_t sector_num, int nb_sectors)
static coroutine_fn int raw_co_discard(BlockDriverState *bs,
int64_t sector_num, int nb_sectors)
{
-#ifdef CONFIG_XFS
+#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_XFS)
BDRVRawState *s = bs->opaque;
+#endif
+ int ret = 0;
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+ do {
+ if (fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ sector_num << BDRV_SECTOR_BITS,
+ nb_sectors << BDRV_SECTOR_BITS) == 0) {
+ return 0;
+ }
+ } while (errno == EINTR);
+
+ ret = -errno;
+#endif
+
+#ifdef CONFIG_XFS
if (s->is_xfs) {
return xfs_discard(s, sector_num, nb_sectors);
}
#endif
- return 0;
+ return ret;
}
static QEMUOptionParameter raw_create_options[] = {
diff --git a/configure b/configure
index 837a84a..ff2e373 100755
--- a/configure
+++ b/configure
@@ -2576,6 +2576,22 @@ if compile_prog "" "" ; then
fallocate=yes
fi
+# check for fallocate hole punching
+fallocate_punch_hole=no
+cat > $TMPC << EOF
+#include <fcntl.h>
+#include <linux/falloc.h>
+
+int main(void)
+{
+ fallocate(0, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, 0);
+ return 0;
+}
+EOF
+if compile_prog "" "" ; then
+ fallocate_punch_hole=yes
+fi
+
# check for sync_file_range
sync_file_range=no
cat > $TMPC << EOF
@@ -3485,6 +3501,9 @@ fi
if test "$fallocate" = "yes" ; then
echo "CONFIG_FALLOCATE=y" >> $config_host_mak
fi
+if test "$fallocate_punch_hole" = "yes" ; then
+ echo "CONFIG_FALLOCATE_PUNCH_HOLE=y" >> $config_host_mak
+fi
if test "$sync_file_range" = "yes" ; then
echo "CONFIG_SYNC_FILE_RANGE=y" >> $config_host_mak
fi
--
1.7.10.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] raw-posix: Support discard on more filesystems
2013-01-05 12:05 [Qemu-devel] [PATCH] raw-posix: Support discard on more filesystems Kusanagi Kouichi
@ 2013-01-07 13:54 ` Stefan Hajnoczi
2013-01-09 11:02 ` Paolo Bonzini
1 sibling, 0 replies; 3+ messages in thread
From: Stefan Hajnoczi @ 2013-01-07 13:54 UTC (permalink / raw)
To: Kusanagi Kouichi; +Cc: Kevin Wolf, qemu-devel, Stefan Hajnoczi
On Sat, Jan 05, 2013 at 09:05:10PM +0900, Kusanagi Kouichi wrote:
> @@ -1098,15 +1101,30 @@ static int xfs_discard(BDRVRawState *s, int64_t sector_num, int nb_sectors)
> static coroutine_fn int raw_co_discard(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors)
> {
> -#ifdef CONFIG_XFS
> +#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_XFS)
> BDRVRawState *s = bs->opaque;
> +#endif
> + int ret = 0;
>
> +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
> + do {
> + if (fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> + sector_num << BDRV_SECTOR_BITS,
> + nb_sectors << BDRV_SECTOR_BITS) == 0) {
> + return 0;
> + }
> + } while (errno == EINTR);
Is fallocate(fd, FALLOC_FL_PUNCH_HOLE) a blocking operation?
If yes, we need to perform this call in an aio worker thread (see
read/write/flush/ioctl in block/raw-posix.c). Failure to do this means
QEMU and the guest will be blocked during fallocate and this causes poor
performance.
Stefan
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] raw-posix: Support discard on more filesystems
2013-01-05 12:05 [Qemu-devel] [PATCH] raw-posix: Support discard on more filesystems Kusanagi Kouichi
2013-01-07 13:54 ` Stefan Hajnoczi
@ 2013-01-09 11:02 ` Paolo Bonzini
1 sibling, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2013-01-09 11:02 UTC (permalink / raw)
To: Kusanagi Kouichi; +Cc: Kevin Wolf, qemu-devel, Stefan Hajnoczi
Il 05/01/2013 13:05, Kusanagi Kouichi ha scritto:
> Linux 2.6.38 introduced the filesystem independent interface to
> deallocate part of a file. As of Linux 3.7, btrfs, ext4, ocfs2,
> tmpfs and xfs support it.
>
> Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
> ---
> block/raw-posix.c | 22 ++++++++++++++++++++--
> configure | 19 +++++++++++++++++++
> 2 files changed, 39 insertions(+), 2 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 87d888e..66ba0b5 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -59,6 +59,9 @@
> #ifdef CONFIG_FIEMAP
> #include <linux/fiemap.h>
> #endif
> +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
> +#include <linux/falloc.h>
> +#endif
> #if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
> #include <sys/disk.h>
> #include <sys/cdio.h>
> @@ -1098,15 +1101,30 @@ static int xfs_discard(BDRVRawState *s, int64_t sector_num, int nb_sectors)
> static coroutine_fn int raw_co_discard(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors)
> {
> -#ifdef CONFIG_XFS
> +#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_XFS)
> BDRVRawState *s = bs->opaque;
> +#endif
> + int ret = 0;
>
> +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
> + do {
> + if (fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> + sector_num << BDRV_SECTOR_BITS,
> + nb_sectors << BDRV_SECTOR_BITS) == 0) {
The last argument needs a cast to int64_t.
I was going to post a similar patch, I'll take the best parts of yours
and mine. :)
Paolo
> + return 0;
> + }
> + } while (errno == EINTR);
> +
> + ret = -errno;
> +#endif
> +
> +#ifdef CONFIG_XFS
> if (s->is_xfs) {
> return xfs_discard(s, sector_num, nb_sectors);
> }
> #endif
>
> - return 0;
> + return ret;
> }
>
> static QEMUOptionParameter raw_create_options[] = {
> diff --git a/configure b/configure
> index 837a84a..ff2e373 100755
> --- a/configure
> +++ b/configure
> @@ -2576,6 +2576,22 @@ if compile_prog "" "" ; then
> fallocate=yes
> fi
>
> +# check for fallocate hole punching
> +fallocate_punch_hole=no
> +cat > $TMPC << EOF
> +#include <fcntl.h>
> +#include <linux/falloc.h>
> +
> +int main(void)
> +{
> + fallocate(0, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, 0);
> + return 0;
> +}
> +EOF
> +if compile_prog "" "" ; then
> + fallocate_punch_hole=yes
> +fi
> +
> # check for sync_file_range
> sync_file_range=no
> cat > $TMPC << EOF
> @@ -3485,6 +3501,9 @@ fi
> if test "$fallocate" = "yes" ; then
> echo "CONFIG_FALLOCATE=y" >> $config_host_mak
> fi
> +if test "$fallocate_punch_hole" = "yes" ; then
> + echo "CONFIG_FALLOCATE_PUNCH_HOLE=y" >> $config_host_mak
> +fi
> if test "$sync_file_range" = "yes" ; then
> echo "CONFIG_SYNC_FILE_RANGE=y" >> $config_host_mak
> fi
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-01-05 12:05 [Qemu-devel] [PATCH] raw-posix: Support discard on more filesystems Kusanagi Kouichi
2013-01-07 13:54 ` Stefan Hajnoczi
2013-01-09 11:02 ` Paolo Bonzini
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