Set zvol discard_granularity to the volblocksize.

Currently, zvols have a discard granularity set to 0, which suggests to the upper layer that discard requests of arbirarily small size and alignment can be made efficiently. In practice however, ZFS does not handle unaligned discard requests efficiently: indeed, it is unable to free a part of a block. It will write zeros to the specified range instead, which is both useless and inefficient (see dnode_free_range). With this patch, zvol block devices expose volblocksize as their discard granularity, so the upper layer is aware that it's not supposed to send discard requests smaller than volblocksize. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #862
2012-08-01 10:29:59 +02:00 · 2012-08-01 10:29:59 +02:00 · ee5fd0bb80
parent 9a512dca97
commit ee5fd0bb80
61 changed files with 233 additions and 0 deletions
--- a/Makefile.in
+++ b/Makefile.in
@ -91,6 +91,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/Makefile.in
+++ b/cmd/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/mount_zfs/Makefile.in
+++ b/cmd/mount_zfs/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/vdev_id/Makefile.in
+++ b/cmd/vdev_id/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zdb/Makefile.in
+++ b/cmd/zdb/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zfs/Makefile.in
+++ b/cmd/zfs/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zinject/Makefile.in
+++ b/cmd/zinject/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zpios/Makefile.in
+++ b/cmd/zpios/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zpool/Makefile.in
+++ b/cmd/zpool/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zpool_id/Makefile.in
+++ b/cmd/zpool_id/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zpool_layout/Makefile.in
+++ b/cmd/zpool_layout/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/ztest/Makefile.in
+++ b/cmd/ztest/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/cmd/zvol_id/Makefile.in
+++ b/cmd/zvol_id/Makefile.in
@ -71,6 +71,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/config/kernel-discard-granularity.m4
+++ b/config/kernel-discard-granularity.m4
@ -0,0 +1,20 @@
+dnl #
+dnl # 2.6.33 API change
+dnl # Discard granularity and alignment restrictions may now be set.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_DISCARD_GRANULARITY], [
+	AC_MSG_CHECKING([whether ql->discard_granularity is available])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/blkdev.h>
+	],[
+		struct queue_limits ql __attribute__ ((unused));
+
+		ql.discard_granularity = 0;
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_DISCARD_GRANULARITY, 1,
+		          [ql->discard_granularity is available])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
--- a/config/kernel.m4
+++ b/config/kernel.m4
@ -39,6 +39,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_GET_GENDISK
 	ZFS_AC_KERNEL_RQ_IS_SYNC
 	ZFS_AC_KERNEL_RQ_FOR_EACH_SEGMENT
+	ZFS_AC_KERNEL_DISCARD_GRANULARITY
 	ZFS_AC_KERNEL_CONST_XATTR_HANDLER
 	ZFS_AC_KERNEL_XATTR_HANDLER_GET
 	ZFS_AC_KERNEL_XATTR_HANDLER_SET
--- a/138
+++ b/138
@ -15369,6 +15369,75 @@ fi

 	EXTRA_KCFLAGS="$tmp_flags"

+
+	{ $as_echo "$as_me:$LINENO: checking whether ql->discard_granularity is available" >&5
+$as_echo_n "checking whether ql->discard_granularity is available... " >&6; }
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#include <linux/blkdev.h>
+
+int
+main (void)
+{
+
+		struct queue_limits ql __attribute__ ((unused));
+
+		ql.discard_granularity = 0;
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build && touch build/conftest.mod.c
+	echo "obj-m := conftest.o" >build/Makefile
+	modpost_flag=''
+	test "x$enable_linux_builtin" = xyes && modpost_flag='modpost=true' # fake modpost stage
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build $modpost_flag'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_DISCARD_GRANULARITY 1
+_ACEOF
+
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+		{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+
+fi
+
+	rm -Rf build
+
+
+
 	{ $as_echo "$as_me:$LINENO: checking whether super_block uses const struct xattr_hander" >&5
 $as_echo_n "checking whether super_block uses const struct xattr_hander... " >&6; }

@ -22873,6 +22942,75 @@ fi

 	EXTRA_KCFLAGS="$tmp_flags"

+
+	{ $as_echo "$as_me:$LINENO: checking whether ql->discard_granularity is available" >&5
+$as_echo_n "checking whether ql->discard_granularity is available... " >&6; }
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#include <linux/blkdev.h>
+
+int
+main (void)
+{
+
+		struct queue_limits ql __attribute__ ((unused));
+
+		ql.discard_granularity = 0;
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build && touch build/conftest.mod.c
+	echo "obj-m := conftest.o" >build/Makefile
+	modpost_flag=''
+	test "x$enable_linux_builtin" = xyes && modpost_flag='modpost=true' # fake modpost stage
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build $modpost_flag'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_DISCARD_GRANULARITY 1
+_ACEOF
+
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+		{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+
+fi
+
+	rm -Rf build
+
+
+
 	{ $as_echo "$as_me:$LINENO: checking whether super_block uses const struct xattr_hander" >&5
 $as_echo_n "checking whether super_block uses const struct xattr_hander... " >&6; }

--- a/dracut/90zfs/Makefile.in
+++ b/dracut/90zfs/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/dracut/Makefile.in
+++ b/dracut/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/etc/Makefile.in
+++ b/etc/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/etc/init.d/Makefile.in
+++ b/etc/init.d/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/etc/zfs/Makefile.in
+++ b/etc/zfs/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/include/Makefile.in
+++ b/include/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/include/linux/Makefile.in
+++ b/include/linux/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/include/linux/blkdev_compat.h
+++ b/include/linux/blkdev_compat.h
@ -432,6 +432,21 @@ bio_set_flags_failfast(struct block_device *bdev, int *flags)
 # define VDEV_REQ_DISCARD		REQ_DISCARD
 #endif

+/*
+ * 2.6.33 API change
+ * Discard granularity and alignment restrictions may now be set.  For
+ * older kernels which do not support this it is safe to skip it.
+ */
+#ifdef HAVE_DISCARD_GRANULARITY
+static inline void
+blk_queue_discard_granularity(struct request_queue *q, unsigned int dg)
+{
+	q->limits.discard_granularity = dg;
+}
+#else
+#define blk_queue_discard_granularity(x, dg)	((void)0)
+#endif /* HAVE_DISCARD_GRANULARITY */
+
 /*
 * Default Linux IO Scheduler,
 * Setting the scheduler to noop will allow the Linux IO scheduler to
--- a/include/sys/Makefile.in
+++ b/include/sys/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/include/sys/fm/Makefile.in
+++ b/include/sys/fm/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/include/sys/fm/fs/Makefile.in
+++ b/include/sys/fm/fs/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/include/sys/fs/Makefile.in
+++ b/include/sys/fs/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libavl/Makefile.in
+++ b/lib/libavl/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libefi/Makefile.in
+++ b/lib/libefi/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libnvpair/Makefile.in
+++ b/lib/libnvpair/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libshare/Makefile.in
+++ b/lib/libshare/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/Makefile.in
+++ b/lib/libspl/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/asm-generic/Makefile.in
+++ b/lib/libspl/asm-generic/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/asm-i386/Makefile.in
+++ b/lib/libspl/asm-i386/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/asm-x86_64/Makefile.in
+++ b/lib/libspl/asm-x86_64/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/Makefile.in
+++ b/lib/libspl/include/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/ia32/Makefile.in
+++ b/lib/libspl/include/ia32/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/ia32/sys/Makefile.in
+++ b/lib/libspl/include/ia32/sys/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/rpc/Makefile.in
+++ b/lib/libspl/include/rpc/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/sys/Makefile.in
+++ b/lib/libspl/include/sys/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/sys/dktp/Makefile.in
+++ b/lib/libspl/include/sys/dktp/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/sys/sysevent/Makefile.in
+++ b/lib/libspl/include/sys/sysevent/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libspl/include/util/Makefile.in
+++ b/lib/libspl/include/util/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libunicode/Makefile.in
+++ b/lib/libunicode/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libuutil/Makefile.in
+++ b/lib/libuutil/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libzfs/Makefile.in
+++ b/lib/libzfs/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/lib/libzpool/Makefile.in
+++ b/lib/libzpool/Makefile.in
@ -70,6 +70,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/man/Makefile.in
+++ b/man/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/man/man5/Makefile.in
+++ b/man/man5/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/man/man8/Makefile.in
+++ b/man/man8/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@ -1245,6 +1245,7 @@ __zvol_create_minor(const char *name)
 #ifdef HAVE_BLK_QUEUE_DISCARD
 	blk_queue_max_discard_sectors(zv->zv_queue,
 	    (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
+	blk_queue_discard_granularity(zv->zv_queue, zv->zv_volblocksize);
 	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
 #endif
 #ifdef HAVE_BLK_QUEUE_NONROT
--- a/scripts/Makefile.in
+++ b/scripts/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/scripts/zpios-profile/Makefile.in
+++ b/scripts/zpios-profile/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/scripts/zpios-test/Makefile.in
+++ b/scripts/zpios-test/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/scripts/zpool-config/Makefile.in
+++ b/scripts/zpool-config/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/scripts/zpool-layout/Makefile.in
+++ b/scripts/zpool-layout/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/udev/Makefile.in
+++ b/udev/Makefile.in
@ -68,6 +68,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/udev/rules.d/Makefile.in
+++ b/udev/rules.d/Makefile.in
@ -69,6 +69,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/kernel-create-umode-t.m4 \
 	$(top_srcdir)/config/kernel-d-make-root.m4 \
 	$(top_srcdir)/config/kernel-d-obtain-alias.m4 \
+	$(top_srcdir)/config/kernel-discard-granularity.m4 \
 	$(top_srcdir)/config/kernel-encode-fh-inode.m4 \
 	$(top_srcdir)/config/kernel-evict-inode.m4 \
 	$(top_srcdir)/config/kernel-fallocate.m4 \
--- a/zfs_config.h.in
+++ b/zfs_config.h.in
@ -120,6 +120,9 @@
 /* xattr_handler->set() wants dentry */
 #undef HAVE_DENTRY_XATTR_SET

+/* ql->discard_granularity is available */
+#undef HAVE_DISCARD_GRANULARITY
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H