[Libguestfs] [PATCH nbdcopy] copy: Implement extent metadata for efficient copying.
Richard W.M. Jones
rjones at redhat.com
Tue Nov 24 13:04:53 UTC 2020
This implements these interconnected options:
--allocated
--destination-is-zero (alias: --target-is-zero)
--no-extents
---
TODO | 6 +-
copy/Makefile.am | 7 +
copy/copy-sparse-allocated.sh | 92 ++++++++++++++
copy/copy-sparse-no-extents.sh | 92 ++++++++++++++
copy/copy-sparse.sh | 97 ++++++++++++++
copy/file-ops.c | 181 ++++++++++++++++++++++++++
copy/main.c | 107 ++++++++++++++--
copy/multi-thread-copying.c | 226 ++++++++++++++++++++++++---------
copy/nbd-ops.c | 176 +++++++++++++++++++++++++
copy/nbdcopy.h | 50 ++++++++
copy/nbdcopy.pod | 32 ++++-
copy/pipe-ops.c | 30 ++++-
12 files changed, 1015 insertions(+), 81 deletions(-)
diff --git a/TODO b/TODO
index 9e5c821..8c0402e 100644
--- a/TODO
+++ b/TODO
@@ -30,9 +30,9 @@ Performance: Chart it over various buffer sizes and threads, as that
Examine other fuzzers: https://gitlab.com/akihe/radamsa
nbdcopy:
- - Properly handle extents/sparseness in input and output.
- - Write zeroes efficiently.
- - Detect zeroes (optionally) and turn into sparseness.
+ - --synchronous mode does not yet support extents.
+ - Detect zeroes (optionally) and turn into sparseness
+ (like qemu-img convert -S).
- Progress bar: allow it to be written to a file descriptor
and/or written in a machine-consumable format.
- Minimum/preferred/maximum block size.
diff --git a/copy/Makefile.am b/copy/Makefile.am
index 8f2d168..cfbc386 100644
--- a/copy/Makefile.am
+++ b/copy/Makefile.am
@@ -26,6 +26,9 @@ EXTRA_DIST = \
copy-nbd-to-small-block-error.sh \
copy-nbd-to-small-nbd-error.sh \
copy-nbd-to-stdout.sh \
+ copy-sparse.sh \
+ copy-sparse-allocated.sh \
+ copy-sparse-no-extents.sh \
copy-stdin-to-nbd.sh \
nbdcopy.pod \
$(NULL)
@@ -46,6 +49,7 @@ nbdcopy_SOURCES = \
$(NULL)
nbdcopy_CPPFLAGS = \
-I$(top_srcdir)/include \
+ -I$(top_srcdir)/common/include \
-I$(top_srcdir)/common/utils \
$(NULL)
nbdcopy_CFLAGS = \
@@ -88,6 +92,9 @@ TESTS += \
copy-nbd-to-small-nbd-error.sh \
copy-stdin-to-nbd.sh \
copy-nbd-to-stdout.sh \
+ copy-sparse.sh \
+ copy-sparse-allocated.sh \
+ copy-sparse-no-extents.sh \
$(ROOT_TESTS) \
$(NULL)
diff --git a/copy/copy-sparse-allocated.sh b/copy/copy-sparse-allocated.sh
new file mode 100755
index 0000000..203c3b9
--- /dev/null
+++ b/copy/copy-sparse-allocated.sh
@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+# nbd client library in userspace
+# Copyright (C) 2020 Red Hat Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+# Adapted from copy-sparse.sh.
+#
+# This test depends on the nbdkit default sparse block size (32K).
+
+. ../tests/functions.sh
+
+set -e
+set -x
+
+requires nbdkit --version
+requires nbdkit --exit-with-parent --version
+requires nbdkit data --version
+requires nbdkit eval --version
+
+out=copy-sparse-allocated.out
+cleanup_fn rm -f $out
+
+$VG nbdcopy --allocated -- \
+ [ nbdkit --exit-with-parent data data='
+ 1
+ @1073741823 1
+ @4294967295 1
+ @4294967296 1
+ ' ] \
+ [ nbdkit --exit-with-parent eval \
+ get_size=' echo 7E ' \
+ pwrite=" echo \$@ >> $out " \
+ trim=" echo \$@ >> $out " \
+ zero=" echo \$@ >> $out " ]
+
+sort -o $out $out
+
+echo Output:
+cat $out
+
+if [ "$(cat $out)" != "pwrite 1 4294967296
+pwrite 32768 0
+pwrite 32768 1073709056
+pwrite 32768 4294934528
+zero 134184960 32768
+zero 134184960 4160749568
+zero 134184960 939524096
+zero 134217728 1073741824
+zero 134217728 1207959552
+zero 134217728 134217728
+zero 134217728 1342177280
+zero 134217728 1476395008
+zero 134217728 1610612736
+zero 134217728 1744830464
+zero 134217728 1879048192
+zero 134217728 2013265920
+zero 134217728 2147483648
+zero 134217728 2281701376
+zero 134217728 2415919104
+zero 134217728 2550136832
+zero 134217728 268435456
+zero 134217728 2684354560
+zero 134217728 2818572288
+zero 134217728 2952790016
+zero 134217728 3087007744
+zero 134217728 3221225472
+zero 134217728 3355443200
+zero 134217728 3489660928
+zero 134217728 3623878656
+zero 134217728 3758096384
+zero 134217728 3892314112
+zero 134217728 402653184
+zero 134217728 4026531840
+zero 134217728 536870912
+zero 134217728 671088640
+zero 134217728 805306368" ]; then
+ echo "$0: output does not match expected"
+ exit 1
+fi
diff --git a/copy/copy-sparse-no-extents.sh b/copy/copy-sparse-no-extents.sh
new file mode 100755
index 0000000..e976d55
--- /dev/null
+++ b/copy/copy-sparse-no-extents.sh
@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+# nbd client library in userspace
+# Copyright (C) 2020 Red Hat Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+# Adapted from copy-sparse.sh
+#
+# This test depends on the nbdkit default sparse block size (32K).
+
+. ../tests/functions.sh
+
+set -e
+set -x
+
+# Skip this test under valgrind, it takes too long.
+if [ "x$LIBNBD_VALGRIND" = "x1" ]; then
+ echo "$0: test skipped under valgrind"
+ exit 77
+fi
+
+requires nbdkit --version
+requires nbdkit --exit-with-parent --version
+requires nbdkit data --version
+requires nbdkit eval --version
+
+out=copy-sparse-no-extents.out
+cleanup_fn rm -f $out
+
+$VG nbdcopy --no-extents -- \
+ [ nbdkit --exit-with-parent data data='
+ 1
+ @1073741823 1
+ ' ] \
+ [ nbdkit --exit-with-parent eval \
+ get_size=' echo 7E ' \
+ pwrite=" echo \$@ >> $out " \
+ trim=" echo \$@ >> $out " \
+ zero=" echo \$@ >> $out " ]
+
+sort -n -o $out $out
+
+echo Output:
+cat $out
+
+if [ "$(cat $out)" != "pwrite 33554432 0
+pwrite 33554432 100663296
+pwrite 33554432 1006632960
+pwrite 33554432 1040187392
+pwrite 33554432 134217728
+pwrite 33554432 167772160
+pwrite 33554432 201326592
+pwrite 33554432 234881024
+pwrite 33554432 268435456
+pwrite 33554432 301989888
+pwrite 33554432 33554432
+pwrite 33554432 335544320
+pwrite 33554432 369098752
+pwrite 33554432 402653184
+pwrite 33554432 436207616
+pwrite 33554432 469762048
+pwrite 33554432 503316480
+pwrite 33554432 536870912
+pwrite 33554432 570425344
+pwrite 33554432 603979776
+pwrite 33554432 637534208
+pwrite 33554432 67108864
+pwrite 33554432 671088640
+pwrite 33554432 704643072
+pwrite 33554432 738197504
+pwrite 33554432 771751936
+pwrite 33554432 805306368
+pwrite 33554432 838860800
+pwrite 33554432 872415232
+pwrite 33554432 905969664
+pwrite 33554432 939524096
+pwrite 33554432 973078528" ]; then
+ echo "$0: output does not match expected"
+ exit 1
+fi
diff --git a/copy/copy-sparse.sh b/copy/copy-sparse.sh
new file mode 100755
index 0000000..2fc4d9a
--- /dev/null
+++ b/copy/copy-sparse.sh
@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+# nbd client library in userspace
+# Copyright (C) 2020 Red Hat Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+# This test depends on the nbdkit default sparse block size (32K).
+
+. ../tests/functions.sh
+
+set -e
+set -x
+
+requires nbdkit --version
+requires nbdkit --exit-with-parent --version
+requires nbdkit data --version
+requires nbdkit eval --version
+
+out=copy-sparse.out
+cleanup_fn rm -f $out
+
+# Copy from a sparse data disk to an nbdkit-eval-plugin instance which
+# is logging everything. This allows us to see exactly what nbdcopy
+# is writing, to ensure it is writing and trimming the target as
+# expected.
+$VG nbdcopy -- \
+ [ nbdkit --exit-with-parent data data='
+ 1
+ @1073741823 1
+ @4294967295 1
+ @4294967296 1
+ ' ] \
+ [ nbdkit --exit-with-parent eval \
+ get_size=' echo 7E ' \
+ pwrite=" echo \$@ >> $out " \
+ trim=" echo \$@ >> $out " \
+ zero=" echo \$@ >> $out " ]
+
+# Order of the output could vary because requests are sent in
+# parallel.
+sort -n -o $out $out
+
+echo Output:
+cat $out
+
+# Check the output matches expected.
+if [ "$(cat $out)" != "pwrite 1 4294967296
+pwrite 32768 0
+pwrite 32768 1073709056
+pwrite 32768 4294934528
+trim 134184960 32768
+trim 134184960 4160749568
+trim 134184960 939524096
+trim 134217728 1073741824
+trim 134217728 1207959552
+trim 134217728 134217728
+trim 134217728 1342177280
+trim 134217728 1476395008
+trim 134217728 1610612736
+trim 134217728 1744830464
+trim 134217728 1879048192
+trim 134217728 2013265920
+trim 134217728 2147483648
+trim 134217728 2281701376
+trim 134217728 2415919104
+trim 134217728 2550136832
+trim 134217728 268435456
+trim 134217728 2684354560
+trim 134217728 2818572288
+trim 134217728 2952790016
+trim 134217728 3087007744
+trim 134217728 3221225472
+trim 134217728 3355443200
+trim 134217728 3489660928
+trim 134217728 3623878656
+trim 134217728 3758096384
+trim 134217728 3892314112
+trim 134217728 402653184
+trim 134217728 4026531840
+trim 134217728 536870912
+trim 134217728 671088640
+trim 134217728 805306368" ]; then
+ echo "$0: output does not match expected"
+ exit 1
+fi
diff --git a/copy/file-ops.c b/copy/file-ops.c
index 9e94b30..cd19e81 100644
--- a/copy/file-ops.c
+++ b/copy/file-ops.c
@@ -24,7 +24,16 @@
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <pthread.h>
+
+#if defined (__linux__)
+#include <linux/fs.h> /* For BLKZEROOUT */
+#endif
+
+#include "isaligned.h"
#include "nbdcopy.h"
static size_t
@@ -74,6 +83,64 @@ file_synch_write (struct rw *rw,
}
}
+static bool
+file_synch_trim (struct rw *rw, uint64_t offset, uint64_t count)
+{
+ assert (rw->t == LOCAL);
+
+#ifdef FALLOC_FL_PUNCH_HOLE
+ int fd = rw->u.local.fd;
+ int r;
+
+ r = fallocate (fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ offset, count);
+ if (r == -1) {
+ perror ("fallocate: FALLOC_FL_PUNCH_HOLE");
+ exit (EXIT_FAILURE);
+ }
+ return true;
+#else /* !FALLOC_FL_PUNCH_HOLE */
+ return false;
+#endif
+}
+
+static bool
+file_synch_zero (struct rw *rw, uint64_t offset, uint64_t count)
+{
+ assert (rw->t == LOCAL);
+
+ if (S_ISREG (rw->u.local.stat.st_mode)) {
+#ifdef FALLOC_FL_ZERO_RANGE
+ int fd = rw->u.local.fd;
+ int r;
+
+ r = fallocate (fd, FALLOC_FL_ZERO_RANGE, offset, count);
+ if (r == -1) {
+ perror ("fallocate: FALLOC_FL_ZERO_RANGE");
+ exit (EXIT_FAILURE);
+ }
+ return true;
+#endif
+ }
+ else if (S_ISBLK (rw->u.local.stat.st_mode) &&
+ IS_ALIGNED (offset | count, rw->u.local.sector_size)) {
+#ifdef BLKZEROOUT
+ int fd = rw->u.local.fd;
+ int r;
+ uint64_t range[2] = {offset, count};
+
+ r = ioctl (fd, BLKZEROOUT, &range);
+ if (r == -1) {
+ perror ("ioctl: BLKZEROOUT");
+ exit (EXIT_FAILURE);
+ }
+ return true;
+#endif
+ }
+
+ return false;
+}
+
static void
file_asynch_read (struct rw *rw,
struct buffer *buffer,
@@ -104,9 +171,123 @@ file_asynch_write (struct rw *rw,
}
}
+static bool
+file_asynch_trim (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb)
+{
+ assert (rw->t == LOCAL);
+
+ if (!file_synch_trim (rw, buffer->offset, buffer->len))
+ return false;
+ errno = 0;
+ if (cb.callback (cb.user_data, &errno) == -1) {
+ perror (rw->name);
+ exit (EXIT_FAILURE);
+ }
+ return true;
+}
+
+static bool
+file_asynch_zero (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb)
+{
+ assert (rw->t == LOCAL);
+
+ if (!file_synch_zero (rw, buffer->offset, buffer->len))
+ return false;
+ errno = 0;
+ if (cb.callback (cb.user_data, &errno) == -1) {
+ perror (rw->name);
+ exit (EXIT_FAILURE);
+ }
+ return true;
+}
+
+static void
+file_get_extents (struct rw *rw, uintptr_t index,
+ uint64_t offset, uint64_t count,
+ extent_list *ret)
+{
+ assert (rw->t == LOCAL);
+
+ ret->size = 0;
+
+#ifdef SEEK_HOLE
+ static pthread_mutex_t lseek_lock = PTHREAD_MUTEX_INITIALIZER;
+
+ if (rw->u.local.seek_hole_supported) {
+ uint64_t end = offset + count;
+ int fd = rw->u.local.fd;
+ off_t pos;
+ struct extent e;
+
+ pthread_mutex_lock (&lseek_lock);
+
+ /* This loop is taken pretty much verbatim from nbdkit-file-plugin. */
+ do {
+ pos = lseek (fd, offset, SEEK_DATA);
+ if (pos == -1) {
+ if (errno == ENXIO)
+ pos = end;
+ else {
+ perror ("lseek: SEEK_DATA");
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ /* We know there is a hole from offset to pos-1. */
+ if (pos > offset) {
+ e.offset = offset;
+ e.length = pos - offset;
+ e.hole = true;
+ if (extent_list_append (ret, e) == -1) {
+ perror ("realloc");
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ offset = pos;
+ if (offset >= end)
+ break;
+
+ pos = lseek (fd, offset, SEEK_HOLE);
+ if (pos == -1) {
+ perror ("lseek: SEEK_HOLE");
+ exit (EXIT_FAILURE);
+ }
+
+ /* We know there is allocated data from offset to pos-1. */
+ if (pos > offset) {
+ e.offset = offset;
+ e.length = pos - offset;
+ e.hole = false;
+ if (extent_list_append (ret, e) == -1) {
+ perror ("realloc");
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ offset = pos;
+ } while (offset < end);
+
+ pthread_mutex_unlock (&lseek_lock);
+ return;
+ }
+#endif
+
+ /* Otherwise return the default extent covering the whole range. */
+ default_get_extents (rw, index, offset, count, ret);
+}
+
+
struct rw_ops file_ops = {
.synch_read = file_synch_read,
.synch_write = file_synch_write,
+ .synch_trim = file_synch_trim,
+ .synch_zero = file_synch_zero,
.asynch_read = file_asynch_read,
.asynch_write = file_asynch_write,
+ .asynch_trim = file_asynch_trim,
+ .asynch_zero = file_asynch_zero,
+ .get_extents = file_get_extents,
};
diff --git a/copy/main.c b/copy/main.c
index 0b0589e..8187944 100644
--- a/copy/main.c
+++ b/copy/main.c
@@ -27,9 +27,11 @@
#include <limits.h>
#include <fcntl.h>
#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
-#include <assert.h>
+#include <sys/ioctl.h>
#include <pthread.h>
@@ -37,7 +39,10 @@
#include "nbdcopy.h"
+bool allocated; /* --allocated flag */
unsigned connections = 4; /* --connections */
+bool destination_is_zero; /* --destination-is-zero flag */
+bool extents = true; /* ! --no-extents flag */
bool flush; /* --flush flag */
unsigned max_requests = 64; /* --requests */
bool progress; /* -p flag */
@@ -46,13 +51,14 @@ unsigned threads; /* --threads */
struct rw src, dst; /* The source and destination. */
static bool is_nbd_uri (const char *s);
+static bool seek_hole_supported (int fd);
static int open_local (const char *prog,
const char *filename, bool writing, struct rw *rw);
static void open_nbd_uri (const char *prog,
- const char *uri, struct rw *rw);
+ const char *uri, bool writing, struct rw *rw);
static void open_nbd_subprocess (const char *prog,
const char **argv, size_t argc,
- struct rw *rw);
+ bool writing, struct rw *rw);
static void __attribute__((noreturn))
usage (FILE *fp, int exitcode)
@@ -85,19 +91,26 @@ main (int argc, char *argv[])
HELP_OPTION = CHAR_MAX + 1,
LONG_OPTIONS,
SHORT_OPTIONS,
+ ALLOCATED_OPTION,
+ DESTINATION_IS_ZERO_OPTION,
FLUSH_OPTION,
+ NO_EXTENTS_OPTION,
SYNCHRONOUS_OPTION,
};
const char *short_options = "C:pR:T:V";
const struct option long_options[] = {
{ "help", no_argument, NULL, HELP_OPTION },
{ "long-options", no_argument, NULL, LONG_OPTIONS },
+ { "allocated", no_argument, NULL, ALLOCATED_OPTION },
{ "connections", required_argument, NULL, 'C' },
+ { "destination-is-zero",no_argument, NULL, DESTINATION_IS_ZERO_OPTION },
{ "flush", no_argument, NULL, FLUSH_OPTION },
+ { "no-extents", no_argument, NULL, NO_EXTENTS_OPTION },
{ "progress", no_argument, NULL, 'p' },
{ "requests", required_argument, NULL, 'R' },
{ "short-options", no_argument, NULL, SHORT_OPTIONS },
{ "synchronous", no_argument, NULL, SYNCHRONOUS_OPTION },
+ { "target-is-zero", no_argument, NULL, DESTINATION_IS_ZERO_OPTION },
{ "threads", required_argument, NULL, 'T' },
{ "version", no_argument, NULL, 'V' },
{ NULL }
@@ -129,10 +142,22 @@ main (int argc, char *argv[])
}
exit (EXIT_SUCCESS);
+ case ALLOCATED_OPTION:
+ allocated = true;
+ break;
+
+ case DESTINATION_IS_ZERO_OPTION:
+ destination_is_zero = true;
+ break;
+
case FLUSH_OPTION:
flush = true;
break;
+ case NO_EXTENTS_OPTION:
+ extents = false;
+ break;
+
case SYNCHRONOUS_OPTION:
synchronous = true;
break;
@@ -191,7 +216,8 @@ main (int argc, char *argv[])
src.t = NBD;
src.name = argv[optind+1];
open_nbd_subprocess (argv[0],
- (const char **) &argv[optind+1], i-optind-1, &src);
+ (const char **) &argv[optind+1], i-optind-1,
+ false, &src);
optind = i+1;
}
else { /* Source is not [...]. */
@@ -201,7 +227,7 @@ main (int argc, char *argv[])
if (src.t == LOCAL)
src.u.local.fd = open_local (argv[0], src.name, false, &src);
else
- open_nbd_uri (argv[0], src.name, &src);
+ open_nbd_uri (argv[0], src.name, false, &src);
}
if (optind >= argc)
@@ -218,7 +244,8 @@ main (int argc, char *argv[])
dst.t = NBD;
dst.name = argv[optind+1];
open_nbd_subprocess (argv[0],
- (const char **) &argv[optind+1], i-optind-1, &dst);
+ (const char **) &argv[optind+1], i-optind-1,
+ true, &dst);
optind = i+1;
}
else { /* Destination is not [...] */
@@ -228,7 +255,7 @@ main (int argc, char *argv[])
if (dst.t == LOCAL)
dst.u.local.fd = open_local (argv[0], dst.name, true /* writing */, &dst);
else {
- open_nbd_uri (argv[0], dst.name, &dst);
+ open_nbd_uri (argv[0], dst.name, true, &dst);
/* Obviously this is not going to work if the server is
* advertising read-only, so fail early with a nice error message.
@@ -318,6 +345,7 @@ main (int argc, char *argv[])
perror ("truncate");
exit (EXIT_FAILURE);
}
+ destination_is_zero = true;
}
else if (dst.t == NBD) {
dst.size = nbd_get_size (dst.u.nbd.ptr[0]);
@@ -345,16 +373,23 @@ main (int argc, char *argv[])
if (src.t == NBD) {
for (i = 1; i < connections; ++i)
- open_nbd_uri (argv[0], src.name, &src);
+ open_nbd_uri (argv[0], src.name, false, &src);
assert (src.u.nbd.size == connections);
}
if (dst.t == NBD) {
for (i = 1; i < connections; ++i)
- open_nbd_uri (argv[0], dst.name, &dst);
+ open_nbd_uri (argv[0], dst.name, true, &dst);
assert (dst.u.nbd.size == connections);
}
}
+ /* If the source is NBD and we couldn't negotiate meta
+ * base:allocation then turn off extents.
+ */
+ if (src.t == NBD &&
+ !nbd_can_meta_context (src.u.nbd.ptr[0], "base:allocation"))
+ extents = false;
+
/* Start copying. */
if (synchronous)
synch_copying ();
@@ -483,11 +518,18 @@ open_local (const char *prog,
perror ("lseek");
exit (EXIT_FAILURE);
}
+ rw->u.local.seek_hole_supported = seek_hole_supported (fd);
+ rw->u.local.sector_size = 4096;
+#ifdef BLKSSZGET
+ if (ioctl (fd, BLKSSZGET, &rw->u.local.sector_size))
+ fprintf (stderr, "warning: cannot get sector size: %s: %m", rw->name);
+#endif
}
else if (S_ISREG (rw->u.local.stat.st_mode)) {
/* Regular file. */
rw->ops = &file_ops;
rw->size = rw->u.local.stat.st_size;
+ rw->u.local.seek_hole_supported = seek_hole_supported (fd);
}
else {
/* Probably stdin/stdout, a pipe or a socket. Set size == -1
@@ -496,14 +538,26 @@ open_local (const char *prog,
synchronous = true;
rw->ops = &pipe_ops;
rw->size = -1;
+ rw->u.local.seek_hole_supported = false;
}
return fd;
}
+static bool
+seek_hole_supported (int fd)
+{
+#ifndef SEEK_HOLE
+ return false;
+#else
+ off_t r = lseek (fd, 0, SEEK_HOLE);
+ return r >= 0;
+#endif
+}
+
static void
open_nbd_uri (const char *prog,
- const char *uri, struct rw *rw)
+ const char *uri, bool writing, struct rw *rw)
{
struct nbd_handle *nbd;
@@ -514,6 +568,11 @@ open_nbd_uri (const char *prog,
exit (EXIT_FAILURE);
}
nbd_set_uri_allow_local_file (nbd, true); /* Allow ?tls-psk-file. */
+ if (extents && !writing &&
+ nbd_add_meta_context (nbd, "base:allocation") == -1) {
+ fprintf (stderr, "%s: %s\n", prog, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
if (handles_append (&rw->u.nbd, nbd) == -1) {
perror ("realloc");
@@ -531,7 +590,7 @@ DEFINE_VECTOR_TYPE (const_string_vector, const char *);
static void
open_nbd_subprocess (const char *prog,
const char **argv, size_t argc,
- struct rw *rw)
+ bool writing, struct rw *rw)
{
struct nbd_handle *nbd;
const_string_vector copy = empty_vector;
@@ -543,6 +602,11 @@ open_nbd_subprocess (const char *prog,
fprintf (stderr, "%s: %s\n", prog, nbd_get_error ());
exit (EXIT_FAILURE);
}
+ if (extents && !writing &&
+ nbd_add_meta_context (nbd, "base:allocation") == -1) {
+ fprintf (stderr, "%s: %s\n", prog, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
if (handles_append (&rw->u.nbd, nbd) == -1) {
memory_error:
@@ -565,3 +629,24 @@ open_nbd_subprocess (const char *prog,
free (copy.ptr);
}
+
+/* Default implementation of rw->ops->get_extents for backends which
+ * don't/can't support extents. Also used for the --no-extents case.
+ */
+void
+default_get_extents (struct rw *rw, uintptr_t index,
+ uint64_t offset, uint64_t count,
+ extent_list *ret)
+{
+ struct extent e;
+
+ ret->size = 0;
+
+ e.offset = offset;
+ e.length = count;
+ e.hole = false;
+ if (extent_list_append (ret, e) == -1) {
+ perror ("realloc");
+ exit (EXIT_FAILURE);
+ }
+}
diff --git a/copy/multi-thread-copying.c b/copy/multi-thread-copying.c
index 3805daf..8081bb1 100644
--- a/copy/multi-thread-copying.c
+++ b/copy/multi-thread-copying.c
@@ -27,6 +27,7 @@
#include <poll.h>
#include <errno.h>
#include <assert.h>
+#include <sys/stat.h>
#include <pthread.h>
@@ -122,12 +123,14 @@ multi_thread_copying (void)
free (workers);
}
+static void wait_for_request_slots (uintptr_t index);
static unsigned in_flight (struct nbd_handle *src_nbd,
struct nbd_handle *dst_nbd);
static void poll_both_ends (struct nbd_handle *src_nbd,
struct nbd_handle *dst_nbd);
static int finished_read (void *vp, int *error);
-static int finished_write (void *vp, int *error);
+static int free_buffer (void *vp, int *error);
+static void fill_dst_range_with_zeroes (struct buffer *buffer);
/* There are 'threads' worker threads, each copying work ranges from
* src to dst until there are no more work ranges.
@@ -138,13 +141,7 @@ worker_thread (void *indexp)
uintptr_t index = (uintptr_t) indexp;
uint64_t offset, count;
struct nbd_handle *src_nbd, *dst_nbd;
- bool done = false;
-
- if (! get_next_offset (&offset, &count))
- /* No work to do, return immediately. Can happen for files which
- * are smaller than THREAD_WORK_SIZE where multi-conn is enabled.
- */
- return NULL;
+ extent_list exts = empty_vector;
/* In the case where src or dst is NBD, use
* {src|dst}.u.nbd.ptr[index] so that each thread is connected to
@@ -161,54 +158,77 @@ worker_thread (void *indexp)
else
dst_nbd = NULL;
- while (!done) {
- struct buffer *buffer;
- char *data;
- size_t len;
-
- if (count == 0) {
- /* Get another work range. */
- done = ! get_next_offset (&offset, &count);
- if (done) break;
- assert (0 < count && count <= THREAD_WORK_SIZE);
- }
-
- /* If the number of requests in flight exceeds the limit, poll
- * waiting for at least one request to finish. This enforces the
- * user --requests option.
- */
- while (in_flight (src_nbd, dst_nbd) >= max_requests)
- poll_both_ends (src_nbd, dst_nbd);
-
- /* Create a new buffer. This will be freed in a callback handler. */
- len = count;
- if (len > MAX_REQUEST_SIZE)
- len = MAX_REQUEST_SIZE;
- data = malloc (len);
- if (data == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
- buffer = malloc (sizeof *buffer);
- if (buffer == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
- buffer->offset = offset;
- buffer->len = len;
- buffer->data = data;
- buffer->free_data = free;
- buffer->index = index;
-
- /* Begin the asynch read operation. */
- src.ops->asynch_read (&src, buffer,
- (nbd_completion_callback) {
- .callback = finished_read,
- .user_data = buffer,
- });
-
- offset += len;
- count -= len;
+ while (get_next_offset (&offset, &count)) {
+ size_t i;
+
+ assert (0 < count && count <= THREAD_WORK_SIZE);
+ if (extents)
+ src.ops->get_extents (&src, index, offset, count, &exts);
+ else
+ default_get_extents (&src, index, offset, count, &exts);
+
+ for (i = 0; i < exts.size; ++i) {
+ struct buffer *buffer;
+ char *data;
+ size_t len;
+
+ if (exts.ptr[i].hole) {
+ /* The source is a hole so we can proceed directly to
+ * skipping, trimming or writing zeroes at the destination.
+ */
+ buffer = calloc (1, sizeof *buffer);
+ if (buffer == NULL) {
+ perror ("malloc");
+ exit (EXIT_FAILURE);
+ }
+ buffer->offset = exts.ptr[i].offset;
+ buffer->len = exts.ptr[i].length;
+ buffer->index = index;
+ fill_dst_range_with_zeroes (buffer);
+ }
+
+ else /* data */ {
+ /* As the extent might be larger than permitted for a single
+ * command, we may have to split this into multiple read
+ * requests.
+ */
+ while (exts.ptr[i].length > 0) {
+ len = exts.ptr[i].length;
+ if (len > MAX_REQUEST_SIZE)
+ len = MAX_REQUEST_SIZE;
+ data = malloc (len);
+ if (data == NULL) {
+ perror ("malloc");
+ exit (EXIT_FAILURE);
+ }
+ buffer = calloc (1, sizeof *buffer);
+ if (buffer == NULL) {
+ perror ("malloc");
+ exit (EXIT_FAILURE);
+ }
+ buffer->offset = exts.ptr[i].offset;
+ buffer->len = len;
+ buffer->data = data;
+ buffer->free_data = free;
+ buffer->index = index;
+
+ wait_for_request_slots (index);
+
+ /* Begin the asynch read operation. */
+ src.ops->asynch_read (&src, buffer,
+ (nbd_completion_callback) {
+ .callback = finished_read,
+ .user_data = buffer,
+ });
+
+ exts.ptr[i].offset += len;
+ exts.ptr[i].length -= len;
+ }
+ }
+
+ offset += count;
+ count = 0;
+ } /* for extents */
}
/* Wait for in flight NBD requests to finish. */
@@ -218,14 +238,37 @@ worker_thread (void *indexp)
if (progress)
progress_bar (1, 1);
+ free (exts.ptr);
return NULL;
}
+/* If the number of requests in flight exceeds the limit, poll
+ * waiting for at least one request to finish. This enforces
+ * the user --requests option.
+ */
+static void
+wait_for_request_slots (uintptr_t index)
+{
+ struct nbd_handle *src_nbd, *dst_nbd;
+
+ if (src.t == NBD)
+ src_nbd = src.u.nbd.ptr[index];
+ else
+ src_nbd = NULL;
+ if (dst.t == NBD)
+ dst_nbd = dst.u.nbd.ptr[index];
+ else
+ dst_nbd = NULL;
+
+ while (in_flight (src_nbd, dst_nbd) >= max_requests)
+ poll_both_ends (src_nbd, dst_nbd);
+}
+
/* Count the number of NBD commands in flight. Since the commands are
* auto-retired in the callbacks we don't need to count "done"
* commands.
*/
-static inline unsigned
+static unsigned
in_flight (struct nbd_handle *src_nbd, struct nbd_handle *dst_nbd)
{
return
@@ -335,18 +378,79 @@ finished_read (void *vp, int *error)
dst.ops->asynch_write (&dst, buffer,
(nbd_completion_callback) {
- .callback = finished_write,
+ .callback = free_buffer,
.user_data = buffer,
});
return 1; /* auto-retires the command */
}
-/* Callback called when dst has finished one write command. We can
- * now free the buffer.
+/* Fill a range in dst with zeroes. This is called from the copying
+ * loop when we see a hole in the source. Depending on the command
+ * line flags this could mean:
+ *
+ * --destination-is-zero:
+ * do nothing
+ *
+ * --allocated: we must write zeroes either using an efficient
+ * zeroing command or writing a buffer of zeroes
+ *
+ * (neither flag) try trimming if supported, else write zeroes
+ * as above
+ *
+ * This takes over ownership of the buffer and frees it eventually.
*/
+static void
+fill_dst_range_with_zeroes (struct buffer *buffer)
+{
+ char *data;
+
+ if (destination_is_zero)
+ goto free_and_return;
+
+ if (!allocated) {
+ /* Try trimming. */
+ wait_for_request_slots (buffer->index);
+ if (dst.ops->asynch_trim (&dst, buffer,
+ (nbd_completion_callback) {
+ .callback = free_buffer,
+ .user_data = buffer,
+ }))
+ return;
+ }
+
+ /* Try efficient zeroing. */
+ wait_for_request_slots (buffer->index);
+ if (dst.ops->asynch_zero (&dst, buffer,
+ (nbd_completion_callback) {
+ .callback = free_buffer,
+ .user_data = buffer,
+ }))
+ return;
+
+ /* Fall back to loop writing zeroes. This is going to be slow
+ * anyway, so do it synchronously. XXX
+ */
+ data = calloc (1, BUFSIZ);
+ if (!data) {
+ perror ("calloc");
+ exit (EXIT_FAILURE);
+ }
+ while (buffer->len > 0) {
+ size_t len = buffer->len > BUFSIZ ? BUFSIZ : buffer->len;
+
+ dst.ops->synch_write (&dst, data, len, buffer->offset);
+ buffer->len -= len;
+ buffer->offset += len;
+ }
+ free (data);
+
+ free_and_return:
+ free_buffer (buffer, &errno);
+}
+
static int
-finished_write (void *vp, int *error)
+free_buffer (void *vp, int *error)
{
struct buffer *buffer = vp;
diff --git a/copy/nbd-ops.c b/copy/nbd-ops.c
index 3ae01ad..6a8ac95 100644
--- a/copy/nbd-ops.c
+++ b/copy/nbd-ops.c
@@ -57,6 +57,37 @@ nbd_synch_write (struct rw *rw,
}
}
+static bool
+nbd_synch_trim (struct rw *rw, uint64_t offset, uint64_t count)
+{
+ assert (rw->t == NBD);
+
+ if (nbd_can_trim (rw->u.nbd.ptr[0]) == 0)
+ return false;
+
+ if (nbd_trim (rw->u.nbd.ptr[0], count, offset, 0) == -1) {
+ fprintf (stderr, "%s: %s\n", rw->name, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+ return true;
+}
+
+static bool
+nbd_synch_zero (struct rw *rw, uint64_t offset, uint64_t count)
+{
+ assert (rw->t == NBD);
+
+ if (nbd_can_zero (rw->u.nbd.ptr[0]) == 0)
+ return false;
+
+ if (nbd_zero (rw->u.nbd.ptr[0],
+ count, offset, LIBNBD_CMD_FLAG_NO_HOLE) == -1) {
+ fprintf (stderr, "%s: %s\n", rw->name, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+ return true;
+}
+
static void
nbd_asynch_read (struct rw *rw,
struct buffer *buffer,
@@ -87,9 +118,154 @@ nbd_asynch_write (struct rw *rw,
}
}
+static bool
+nbd_asynch_trim (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb)
+{
+ assert (rw->t == NBD);
+
+ if (nbd_can_trim (rw->u.nbd.ptr[0]) == 0)
+ return false;
+
+ if (nbd_aio_trim (rw->u.nbd.ptr[buffer->index],
+ buffer->len, buffer->offset,
+ cb, 0) == -1) {
+ fprintf (stderr, "%s: %s\n", rw->name, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+ return true;
+}
+
+static bool
+nbd_asynch_zero (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb)
+{
+ assert (rw->t == NBD);
+
+ if (nbd_can_zero (rw->u.nbd.ptr[0]) == 0)
+ return false;
+
+ if (nbd_aio_zero (rw->u.nbd.ptr[buffer->index],
+ buffer->len, buffer->offset,
+ cb, LIBNBD_CMD_FLAG_NO_HOLE) == -1) {
+ fprintf (stderr, "%s: %s\n", rw->name, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+ return true;
+}
+
+static int
+add_extent (void *vp, const char *metacontext,
+ uint64_t offset, uint32_t *entries, size_t nr_entries,
+ int *error)
+{
+ extent_list *ret = vp;
+ size_t i;
+
+ if (strcmp (metacontext, "base:allocation") != 0)
+ return 0;
+
+ for (i = 0; i < nr_entries; i += 2) {
+ struct extent e;
+
+ e.offset = offset;
+ e.length = entries[i];
+ /* Note we deliberately don't care about the ZERO flag. */
+ e.hole = (entries[i+1] & LIBNBD_STATE_HOLE) != 0;
+ if (extent_list_append (ret, e) == -1) {
+ perror ("realloc");
+ exit (EXIT_FAILURE);
+ }
+
+ offset += entries[i];
+ }
+
+ return 0;
+}
+
+/* This is done synchronously, but that's fine because commands from
+ * the previous work range in flight continue to run, it's difficult
+ * to (sanely) start new work until we have the full list of extents,
+ * and in almost every case the remote NBD server can answer our
+ * request for extents in a single round trip.
+ */
+static void
+nbd_get_extents (struct rw *rw, uintptr_t index,
+ uint64_t offset, uint64_t count,
+ extent_list *ret)
+{
+ extent_list exts = empty_vector;
+ struct nbd_handle *nbd;
+
+ assert (rw->t == NBD);
+ nbd = rw->u.nbd.ptr[index];
+
+ ret->size = 0;
+
+ while (count > 0) {
+ size_t i;
+
+ exts.size = 0;
+ if (nbd_block_status (nbd, count, offset,
+ (nbd_extent_callback) {
+ .user_data = &exts,
+ .callback = add_extent
+ }, 0) == -1) {
+ /* XXX We could call default_get_extents, but unclear if it's
+ * the right thing to do if the server is returning errors.
+ */
+ fprintf (stderr, "%s: %s\n", rw->name, nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+
+ /* The server should always make progress. */
+ if (exts.size == 0) {
+ fprintf (stderr, "%s: NBD server is broken: it is not returning extent information.\nTry nbdcopy --no-extents as a workaround.\n",
+ rw->name);
+ exit (EXIT_FAILURE);
+ }
+
+ /* Copy the extents returned into the final list (ret). This is
+ * complicated because the extents returned by the server may
+ * begin earlier and begin or end later than the requested size.
+ */
+ for (i = 0; i < exts.size; ++i) {
+ uint64_t d;
+
+ if (exts.ptr[i].offset + exts.ptr[i].length <= offset)
+ continue;
+ if (exts.ptr[i].offset < offset) {
+ d = offset - exts.ptr[i].offset;
+ exts.ptr[i].offset += d;
+ exts.ptr[i].length -= d;
+ assert (exts.ptr[i].offset == offset);
+ }
+ if (exts.ptr[i].offset + exts.ptr[i].length > offset + count) {
+ d = offset + count - exts.ptr[i].offset - exts.ptr[i].length;
+ exts.ptr[i].length -= d;
+ assert (exts.ptr[i].length == offset + count);
+ }
+ if (extent_list_append (ret, exts.ptr[i]) == -1) {
+ perror ("realloc");
+ exit (EXIT_FAILURE);
+ }
+
+ offset += exts.ptr[i].length;
+ count -= exts.ptr[i].length;
+ }
+ }
+
+ free (exts.ptr);
+}
+
struct rw_ops nbd_ops = {
.synch_read = nbd_synch_read,
.synch_write = nbd_synch_write,
+ .synch_trim = nbd_synch_trim,
+ .synch_zero = nbd_synch_zero,
.asynch_read = nbd_asynch_read,
.asynch_write = nbd_asynch_write,
+ .asynch_trim = nbd_asynch_trim,
+ .asynch_zero = nbd_asynch_zero,
+ .get_extents = nbd_get_extents,
};
diff --git a/copy/nbdcopy.h b/copy/nbdcopy.h
index 9e4fc19..d74abad 100644
--- a/copy/nbdcopy.h
+++ b/copy/nbdcopy.h
@@ -47,6 +47,8 @@ struct rw {
struct { /* For LOCAL. */
int fd;
struct stat stat;
+ bool seek_hole_supported;
+ int sector_size;
} local;
handles nbd; /* For NBD, one handle per connection. */
} u;
@@ -63,6 +65,14 @@ struct buffer {
uintptr_t index; /* Thread number. */
};
+/* List of extents for rw->ops->get_extents. */
+struct extent {
+ uint64_t offset;
+ uint64_t length;
+ bool hole;
+};
+DEFINE_VECTOR_TYPE(extent_list, struct extent);
+
/* The operations struct hides some of the differences between local
* file, NBD and pipes from the copying code.
*
@@ -80,6 +90,16 @@ struct rw_ops {
void (*synch_write) (struct rw *rw,
const void *data, size_t len, uint64_t offset);
+ /* Synchronously trim. buffer->data is not used. If not possible,
+ * returns false.
+ */
+ bool (*synch_trim) (struct rw *rw, uint64_t offset, uint64_t count);
+
+ /* Synchronously zero. buffer->data is not used. If not possible,
+ * returns false.
+ */
+ bool (*synch_zero) (struct rw *rw, uint64_t offset, uint64_t count);
+
/* Asynchronous I/O operations. These start the operation and call
* 'cb' on completion.
*
@@ -95,12 +115,42 @@ struct rw_ops {
void (*asynch_write) (struct rw *rw,
struct buffer *buffer,
nbd_completion_callback cb);
+
+ /* Asynchronously trim. buffer->data is not used. If not possible,
+ * returns false.
+ */
+ bool (*asynch_trim) (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb);
+
+ /* Asynchronously zero. buffer->data is not used. If not possible,
+ * returns false.
+ */
+ bool (*asynch_zero) (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb);
+
+ /* Read base:allocation extents metadata for a region of the source.
+ * For local files the same information is read from the kernel.
+ *
+ * Note that qemu-img fetches extents for the entire disk up front,
+ * and we want to avoid doing that because it had very negative
+ * behaviour for certain sources (ie. VDDK).
+ */
+ void (*get_extents) (struct rw *rw, uintptr_t index,
+ uint64_t offset, uint64_t count,
+ extent_list *ret);
};
extern struct rw_ops file_ops;
extern struct rw_ops nbd_ops;
extern struct rw_ops pipe_ops;
+extern void default_get_extents (struct rw *rw, uintptr_t index,
+ uint64_t offset, uint64_t count,
+ extent_list *ret);
+
+extern bool allocated;
extern unsigned connections;
+extern bool destination_is_zero;
+extern bool extents;
extern bool flush;
extern unsigned max_requests;
extern bool progress;
diff --git a/copy/nbdcopy.pod b/copy/nbdcopy.pod
index f654f65..5ff7434 100644
--- a/copy/nbdcopy.pod
+++ b/copy/nbdcopy.pod
@@ -4,7 +4,9 @@ nbdcopy - copy to and from an NBD server
=head1 SYNOPSIS
- nbdcopy [-C N|--connections=N] [--flush] [-p|--progress]
+ nbdcopy [--allocated] [-C N|--connections=N]
+ [--destination-is-zero|--target-is-zero]
+ [--flush] [--no-extents] [-p|--progress]
[-R N|--requests=N] [--synchronous]
[-T N|--threads=N]
SOURCE DESTINATION
@@ -74,6 +76,15 @@ formats use C<qemu-img convert>, see L<qemu-img(1)>.
Display brief command line help and exit.
+=item B<--allocated>
+
+Normally nbdcopy tries to create a sparse output (with holes), if the
+destination supports that. It does this in two ways: either using
+extent informtation from the source to copy holes (see
+I<--no-extents>), or by detecting runs of zeroes (see I<-S>). If you
+use I<--allocated> then nbdcopy creates a fully allocated, non-sparse
+output on the destination.
+
=item B<-C> N
=item B<--connections=>N
@@ -82,11 +93,30 @@ Set the maximum number of NBD connections ("multi-conn"). By default
nbdcopy will try to use multi-conn with up to 4 connections if the NBD
server supports it.
+=item B<--destination-is-zero>
+
+=item B<--target-is-zero>
+
+Assume the destination is already zeroed. This allows nbdcopy to skip
+copying blocks of zeroes from the source to the destination. This is
+not safe unless the destination device is already zeroed.
+(I<--target-is-zero> is provided for compatibility with
+L<qemu-img(1)>.)
+
=item B<--flush>
Flush writes to ensure that everything is written to persistent
storage before nbdcopy exits.
+=item B<--no-extents>
+
+Normally nbdcopy uses extent metadata to skip over parts of the source
+disk which contain holes. If you use this flag, nbdcopy ignores
+extent information and reads everything, which is usually slower. You
+might use this flag in two situations: the source NBD server has
+incorrect metadata information; or the source has very slow extent
+querying so it's faster to simply read all of the data.
+
=item B<-p>
=item B<--progress>
diff --git a/copy/pipe-ops.c b/copy/pipe-ops.c
index e10a31e..0788aae 100644
--- a/copy/pipe-ops.c
+++ b/copy/pipe-ops.c
@@ -61,6 +61,12 @@ pipe_synch_write (struct rw *rw,
}
}
+static bool
+pipe_synch_trim_zero (struct rw *rw, uint64_t offset, uint64_t count)
+{
+ return false; /* not supported by pipes */
+}
+
static void
pipe_asynch_read (struct rw *rw,
struct buffer *buffer,
@@ -77,16 +83,30 @@ pipe_asynch_write (struct rw *rw,
abort (); /* See comment below. */
}
+static bool
+pipe_asynch_trim_zero (struct rw *rw, struct buffer *buffer,
+ nbd_completion_callback cb)
+{
+ return false; /* not supported by pipes */
+}
+
struct rw_ops pipe_ops = {
.synch_read = pipe_synch_read,
.synch_write = pipe_synch_write,
+ .synch_trim = pipe_synch_trim_zero,
+ .synch_zero = pipe_synch_trim_zero,
- /* Asynch pipe operations are not defined. These should never be
- * called because pipes/streams/sockets force --synchronous.
- * Because calling a NULL pointer screws up the stack trace when
- * we're not using frame pointers, these are defined to functions
- * that call abort().
+ /* Asynch pipe read/write operations are not defined. These should
+ * never be called because pipes/streams/sockets force synchronous
+ * mode. Because calling a NULL pointer screws up the stack trace
+ * when we're not using frame pointers, these are defined to
+ * functions that call abort().
*/
.asynch_read = pipe_asynch_read,
.asynch_write = pipe_asynch_write,
+
+ .asynch_trim = pipe_asynch_trim_zero,
+ .asynch_zero = pipe_asynch_trim_zero,
+
+ .get_extents = default_get_extents,
};
--
2.29.0.rc2
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