From 66c76f8acc38f3e0d3b7fd2d362d73c409a1c828 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 14 Feb 2012 11:13:57 +0100
Subject: [PATCH 32/99] raw-posix: add discard support

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1329218101-24213-33-git-send-email-kwolf@redhat.com>
Patchwork-id: 37220
O-Subject: [RHEL-6.3 qemu-kvm PATCH v2 32/96] raw-posix: add discard support
Bugzilla: 783950
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

From: Christoph Hellwig <hch@lst.de>

Bugzilla: 783950

Add support to discard blocks in a raw image residing on an XFS filesystem
by calling the XFS_IOC_UNRESVSP64 ioctl to punch holes.  Support for other
hole punching mechanisms can be added when they become available.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit dce512dedf2b842f453f8b20d6ca37ce283103da)

Conflicts:

	block/raw-posix.c
	configure

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/raw-posix.c |   45 +++++++++++++++++++++++++++++++++++++++++++++
 configure         |   26 ++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 0 deletions(-)

Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
 block/raw-posix.c |   45 +++++++++++++++++++++++++++++++++++++++++++++
 configure         |   26 ++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 0 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index c42d31b..566ffb8 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -72,6 +72,10 @@
 #include <sys/diskslice.h>
 #endif
 
+#ifdef CONFIG_XFS
+#include <xfs/xfs.h>
+#endif
+
 //#define DEBUG_FLOPPY
 
 //#define DEBUG_BLOCK
@@ -124,6 +128,9 @@ typedef struct BDRVRawState {
     uint8_t *aligned_buf;
     unsigned aligned_buf_size;
     bool force_linearize;
+#ifdef CONFIG_XFS
+    bool is_xfs : 1;
+#endif
 } BDRVRawState;
 
 static int fd_open(BlockDriverState *bs);
@@ -233,6 +240,12 @@ static int raw_open_common(BlockDriverState *bs, const char *filename,
 #endif
     }
 
+#ifdef CONFIG_XFS
+    if (platform_test_xfs_fd(s->fd)) {
+        s->is_xfs = 1;
+    }
+#endif
+
     return 0;
 
 out_free_buf:
@@ -790,6 +803,37 @@ static int raw_flush(BlockDriverState *bs)
     return 0;
 }
 
+#ifdef CONFIG_XFS
+static int xfs_discard(BDRVRawState *s, int64_t sector_num, int nb_sectors)
+{
+    struct xfs_flock64 fl;
+
+    memset(&fl, 0, sizeof(fl));
+    fl.l_whence = SEEK_SET;
+    fl.l_start = sector_num << 9;
+    fl.l_len = (int64_t)nb_sectors << 9;
+
+    if (xfsctl(NULL, s->fd, XFS_IOC_UNRESVSP64, &fl) < 0) {
+        DEBUG_BLOCK_PRINT("cannot punch hole (%s)\n", strerror(errno));
+        return -errno;
+    }
+
+    return 0;
+}
+#endif
+
+static int raw_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
+{
+#ifdef CONFIG_XFS
+    BDRVRawState *s = bs->opaque;
+
+    if (s->is_xfs) {
+        return xfs_discard(s, sector_num, nb_sectors);
+    }
+#endif
+
+    return 0;
+}
 
 static QEMUOptionParameter raw_create_options[] = {
     {
@@ -811,6 +855,7 @@ static BlockDriver bdrv_file = {
     .bdrv_close = raw_close,
     .bdrv_create = raw_create,
     .bdrv_flush = raw_flush,
+    .bdrv_discard = raw_discard,
 
     .bdrv_aio_readv = raw_aio_readv,
     .bdrv_aio_writev = raw_aio_writev,
diff --git a/configure b/configure
index c144eba..ecde8bb 100755
--- a/configure
+++ b/configure
@@ -238,6 +238,7 @@ vnc_sasl=""
 xen=""
 linux_aio=""
 vhost_net=""
+xfs=""
 
 gprof="no"
 debug_tcg="no"
@@ -1223,6 +1224,27 @@ EOF
 fi
 
 ##########################################
+# xfsctl() probe, used for raw-posix
+if test "$xfs" != "no" ; then
+  cat > $TMPC << EOF
+#include <xfs/xfs.h>
+int main(void)
+{
+    xfsctl(NULL, 0, 0, NULL);
+    return 0;
+}
+EOF
+  if compile_prog "" "" ; then
+    xfs="yes"
+  else
+    if test "$xfs" = "yes" ; then
+      feature_not_found "xfs"
+    fi
+    xfs=no
+  fi
+fi
+
+##########################################
 # vde libraries probe
 if test "$vde" != "no" ; then
   vde_libs="-lvdeplug"
@@ -2208,6 +2230,7 @@ echo "Trace backend     $trace_backend"
 echo "spice support     $spice"
 echo "nss used          $smartcard_nss"
 echo "Live snapshots    $live_snapshots"
+echo "xfsctl support    $xfs"
 
 if test $sdl_too_old = "yes"; then
 echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -2333,6 +2356,9 @@ fi
 if test "$uuid" = "yes" ; then
   echo "CONFIG_UUID=y" >> $config_host_mak
 fi
+if test "$xfs" = "yes" ; then
+  echo "CONFIG_XFS=y" >> $config_host_mak
+fi
 qemu_version=`head $source_path/VERSION`
 echo "VERSION=$qemu_version" >>$config_host_mak
 echo "PKGVERSION=$pkgversion" >>$config_host_mak
-- 
1.7.7.5

