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import nbdkit-1.16.2-4.module+el8.3.0+6922+fd575af8
2020-07-28 10:32:57 +00:00
From e744dcb38cc52cbe64977efcdd4bc60e802d1b17 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Thu, 23 Jan 2020 19:52:00 +0000
Subject: [PATCH 11/19] New filter: extentlist.
Allows a list of extents to be placed on top of an existing plugin.
(cherry picked from commit 3e770b6d6620a62546849a2863638041c0b00640)
---
TODO | 4 +
configure.ac | 2 +
.../nbdkit-cacheextents-filter.pod | 1 +
filters/extentlist/Makefile.am | 67 ++++
filters/extentlist/extentlist.c | 326 ++++++++++++++++++
.../extentlist/nbdkit-extentlist-filter.pod | 90 +++++
filters/noextents/nbdkit-noextents-filter.pod | 1 +
tests/Makefile.am | 4 +
tests/test-extentlist.sh | 175 ++++++++++
9 files changed, 670 insertions(+)
create mode 100644 filters/extentlist/Makefile.am
create mode 100644 filters/extentlist/extentlist.c
create mode 100644 filters/extentlist/nbdkit-extentlist-filter.pod
create mode 100755 tests/test-extentlist.sh
diff --git a/TODO b/TODO
index d2aca440..2a3e89dc 100644
--- a/TODO
+++ b/TODO
@@ -187,6 +187,10 @@ Suggestions for filters
MBs of extra data)
https://github.com/facebook/zstd/issues/395#issuecomment-535875379
+* nbdkit-extentlist-filter could read the extents generated by
+ qemu-img map, allowing extents to be ported from a qemu block
+ device.
+
nbdkit-rate-filter:
* allow other kinds of traffic shaping such as VBR
diff --git a/configure.ac b/configure.ac
index fde498b8..41e68de3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -896,6 +896,7 @@ filters="\
cow \
delay \
error \
+ extentlist \
fua \
log \
nocache \
@@ -979,6 +980,7 @@ AC_CONFIG_FILES([Makefile
filters/cow/Makefile
filters/delay/Makefile
filters/error/Makefile
+ filters/extentlist/Makefile
filters/fua/Makefile
filters/log/Makefile
filters/nocache/Makefile
diff --git a/filters/cacheextents/nbdkit-cacheextents-filter.pod b/filters/cacheextents/nbdkit-cacheextents-filter.pod
index fdd2285a..bb2514a4 100644
--- a/filters/cacheextents/nbdkit-cacheextents-filter.pod
+++ b/filters/cacheextents/nbdkit-cacheextents-filter.pod
@@ -52,6 +52,7 @@ C<nbdkit-cacheextents-filter> first appeared in nbdkit 1.14.
L<nbdkit(1)>,
L<nbdkit-cache-filter(1)>,
+L<nbdkit-extentlist-filter(1)>,
L<nbdkit-readahead-filter(1)>,
L<nbdkit-vddk-plugin(1)>,
L<nbdkit-filter(3)>,
diff --git a/filters/extentlist/Makefile.am b/filters/extentlist/Makefile.am
new file mode 100644
index 00000000..88a9afe1
--- /dev/null
+++ b/filters/extentlist/Makefile.am
@@ -0,0 +1,67 @@
+# nbdkit
+# Copyright (C) 2019-2020 Red Hat Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+#
+# * Neither the name of Red Hat nor the names of its contributors may be
+# used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+include $(top_srcdir)/common-rules.mk
+
+EXTRA_DIST = nbdkit-extentlist-filter.pod
+
+filter_LTLIBRARIES = nbdkit-extentlist-filter.la
+
+nbdkit_extentlist_filter_la_SOURCES = \
+ extentlist.c \
+ $(top_srcdir)/include/nbdkit-filter.h \
+ $(NULL)
+
+nbdkit_extentlist_filter_la_CPPFLAGS = \
+ -I$(top_srcdir)/include \
+ -I$(top_srcdir)/common/include \
+ -I$(top_srcdir)/common/utils \
+ $(NULL)
+nbdkit_extentlist_filter_la_CFLAGS = $(WARNINGS_CFLAGS)
+nbdkit_extentlist_filter_la_LDFLAGS = \
+ -module -avoid-version -shared \
+ -Wl,--version-script=$(top_srcdir)/filters/filters.syms \
+ $(NULL)
+nbdkit_extentlist_filter_la_LIBADD = \
+ $(top_builddir)/common/utils/libutils.la \
+ $(NULL)
+
+if HAVE_POD
+
+man_MANS = nbdkit-extentlist-filter.1
+CLEANFILES += $(man_MANS)
+
+nbdkit-extentlist-filter.1: nbdkit-extentlist-filter.pod
+ $(PODWRAPPER) --section=1 --man $@ \
+ --html $(top_builddir)/html/$@.html \
+ $<
+
+endif HAVE_POD
diff --git a/filters/extentlist/extentlist.c b/filters/extentlist/extentlist.c
new file mode 100644
index 00000000..5f4990b3
--- /dev/null
+++ b/filters/extentlist/extentlist.c
@@ -0,0 +1,326 @@
+/* nbdkit
+ * Copyright (C) 2019-2020 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <nbdkit-filter.h>
+
+#include "cleanup.h"
+#include "minmax.h"
+
+#define HOLE (NBDKIT_EXTENT_HOLE|NBDKIT_EXTENT_ZERO)
+
+static const char *extentlist;
+
+/* List of extents. Once we've finally parsed them this will be
+ * ordered, non-overlapping and have no gaps.
+ */
+struct extent {
+ uint64_t offset, length;
+ uint32_t type;
+};
+static struct extent *extents;
+static size_t nr_extents, allocated;
+
+/* Insert an extent before i. If i = nr_extents, inserts at the end. */
+static void
+insert_extent (size_t i, struct extent new_extent)
+{
+ if (nr_extents >= allocated) {
+ allocated = allocated == 0 ? 1 : allocated * 2;
+ extents = realloc (extents, (sizeof (struct extent) * allocated));
+ if (extents == NULL) {
+ nbdkit_error ("realloc: %m");
+ exit (EXIT_FAILURE);
+ }
+ }
+ memmove (&extents[i+1], &extents[i],
+ sizeof (struct extent) * (nr_extents-i));
+ extents[i] = new_extent;
+ nr_extents++;
+}
+
+static void
+extentlist_unload (void)
+{
+ free (extents);
+}
+
+/* Called for each key=value passed on the command line. */
+static int
+extentlist_config (nbdkit_next_config *next, void *nxdata,
+ const char *key, const char *value)
+{
+ if (strcmp (key, "extentlist") == 0) {
+ if (extentlist != NULL) {
+ nbdkit_error ("extentlist cannot appear twice");
+ exit (EXIT_FAILURE);
+ }
+ extentlist = value;
+ return 0;
+ }
+ else
+ return next (nxdata, key, value);
+}
+
+static int
+compare_offsets (const void *ev1, const void *ev2)
+{
+ const struct extent *e1 = ev1;
+ const struct extent *e2 = ev2;
+
+ if (e1->offset < e2->offset)
+ return -1;
+ else if (e1->offset > e2->offset)
+ return 1;
+ else
+ return 0;
+}
+
+static int
+compare_ranges (const void *ev1, const void *ev2)
+{
+ const struct extent *e1 = ev1;
+ const struct extent *e2 = ev2;
+
+ if (e1->offset < e2->offset)
+ return -1;
+ else if (e1->offset >= e2->offset + e2->length)
+ return 1;
+ else
+ return 0;
+}
+
+/* Similar to parse_extents in plugins/sh/methods.c */
+static void
+parse_extentlist (void)
+{
+ FILE *fp;
+ CLEANUP_FREE char *line = NULL;
+ size_t linelen = 0;
+ ssize_t len;
+ size_t i;
+ uint64_t end;
+
+ assert (extentlist != NULL);
+ assert (extents == NULL);
+ assert (nr_extents == 0);
+
+ fp = fopen (extentlist, "r");
+ if (!fp) {
+ nbdkit_error ("open: %s: %m", extentlist);
+ exit (EXIT_FAILURE);
+ }
+
+ while ((len = getline (&line, &linelen, fp)) != -1) {
+ const char *delim = " \t";
+ char *sp, *p;
+ int64_t offset, length;
+ uint32_t type;
+
+ if (len > 0 && line[len-1] == '\n') {
+ line[len-1] = '\0';
+ len--;
+ }
+
+ if ((p = strtok_r (line, delim, &sp)) == NULL) {
+ parse_error:
+ nbdkit_error ("%s: cannot parse %s", extentlist, line);
+ exit (EXIT_FAILURE);
+ }
+ offset = nbdkit_parse_size (p);
+ if (offset == -1)
+ exit (EXIT_FAILURE);
+
+ if ((p = strtok_r (NULL, delim, &sp)) == NULL)
+ goto parse_error;
+ length = nbdkit_parse_size (p);
+ if (length == -1)
+ exit (EXIT_FAILURE);
+
+ /* Skip zero length extents. Makes the rest of the code easier. */
+ if (length == 0)
+ continue;
+
+ if ((p = strtok_r (NULL, delim, &sp)) == NULL)
+ /* empty type field means allocated data (0) */
+ type = 0;
+ else if (sscanf (p, "%" SCNu32, &type) == 1)
+ ;
+ else {
+ type = 0;
+ if (strstr (p, "hole") != NULL)
+ type |= NBDKIT_EXTENT_HOLE;
+ if (strstr (p, "zero") != NULL)
+ type |= NBDKIT_EXTENT_ZERO;
+ }
+
+ insert_extent (nr_extents,
+ (struct extent){.offset = offset, .length=length,
+ .type=type});
+ }
+
+ fclose (fp);
+
+ /* Sort the extents by offset. */
+ qsort (extents, nr_extents, sizeof (struct extent), compare_offsets);
+
+ /* There must not be overlaps at this point. */
+ end = 0;
+ for (i = 0; i < nr_extents; ++i) {
+ if (extents[i].offset < end ||
+ extents[i].offset + extents[i].length < extents[i].offset) {
+ nbdkit_error ("extents in the extent list are overlapping");
+ exit (EXIT_FAILURE);
+ }
+ end = extents[i].offset + extents[i].length;
+ }
+
+ /* If there's a gap at the beginning, insert a hole|zero extent. */
+ if (nr_extents == 0 || extents[0].offset > 0) {
+ end = nr_extents == 0 ? UINT64_MAX : extents[0].offset;
+ insert_extent (0, (struct extent){.offset = 0, .length = end,
+ .type = HOLE});
+ }
+
+ /* Now insert hole|zero extents after every extent where there
+ * is a gap between that extent and the next one.
+ */
+ for (i = 0; i < nr_extents-1; ++i) {
+ end = extents[i].offset + extents[i].length;
+ if (end < extents[i+1].offset)
+ insert_extent (i+1, (struct extent){.offset = end,
+ .length = extents[i+1].offset - end,
+ .type = HOLE});
+ }
+
+ /* If there's a gap at the end, insert a hole|zero extent. */
+ end = extents[nr_extents-1].offset + extents[nr_extents-1].length;
+ if (end < UINT64_MAX)
+ insert_extent (nr_extents, (struct extent){.offset = end,
+ .length = UINT64_MAX-end,
+ .type = HOLE});
+
+ /* Debug the final list. */
+ for (i = 0; i < nr_extents; ++i) {
+ nbdkit_debug ("extentlist: "
+ "extent[%zu] = %" PRIu64 "-%" PRIu64 " (length %" PRIu64 ")"
+ " type %" PRIu32,
+ i, extents[i].offset,
+ extents[i].offset + extents[i].length - 1,
+ extents[i].length,
+ extents[i].type);
+ }
+}
+
+static int
+extentlist_config_complete (nbdkit_next_config_complete *next, void *nxdata)
+{
+ if (extentlist == NULL) {
+ nbdkit_error ("you must supply the extentlist parameter "
+ "on the command line");
+ return -1;
+ }
+
+ parse_extentlist ();
+
+ return next (nxdata);
+}
+
+static int
+extentlist_can_extents (struct nbdkit_next_ops *next_ops, void *nxdata,
+ void *handle)
+{
+ return 1;
+}
+
+/* Use ‘-D extentlist.lookup=1’ to debug the function below. */
+int extentlist_debug_lookup = 0;
+
+/* Read extents. */
+static int
+extentlist_extents (struct nbdkit_next_ops *next_ops, void *nxdata,
+ void *handle, uint32_t count, uint64_t offset,
+ uint32_t flags,
+ struct nbdkit_extents *ret_extents,
+ int *err)
+{
+ const struct extent eoffset = { .offset = offset };
+ struct extent *p;
+ ssize_t i;
+ uint64_t end;
+
+ /* Find the starting point in the extents list. */
+ p = bsearch (&eoffset, extents,
+ nr_extents, sizeof (struct extent), compare_ranges);
+ assert (p != NULL);
+ i = p - extents;
+
+ /* Add extents to the output. */
+ while (count > 0) {
+ if (extentlist_debug_lookup)
+ nbdkit_debug ("extentlist lookup: "
+ "loop i=%zd count=%" PRIu32 " offset=%" PRIu64,
+ i, count, offset);
+
+ end = extents[i].offset + extents[i].length;
+ if (nbdkit_add_extent (ret_extents, offset, end - offset,
+ extents[i].type) == -1)
+ return -1;
+
+ count -= MIN (count, end-offset);
+ offset = end;
+ i++;
+ }
+
+ return 0;
+}
+
+static struct nbdkit_filter filter = {
+ .name = "extentlist",
+ .longname = "nbdkit extentlist filter",
+ .unload = extentlist_unload,
+ .config = extentlist_config,
+ .config_complete = extentlist_config_complete,
+ .can_extents = extentlist_can_extents,
+ .extents = extentlist_extents,
+};
+
+NBDKIT_REGISTER_FILTER(filter)
diff --git a/filters/extentlist/nbdkit-extentlist-filter.pod b/filters/extentlist/nbdkit-extentlist-filter.pod
new file mode 100644
index 00000000..adfb4ad8
--- /dev/null
+++ b/filters/extentlist/nbdkit-extentlist-filter.pod
@@ -0,0 +1,90 @@
+=head1 NAME
+
+nbdkit-extentlist-filter - place extent list over a plugin
+
+=head1 SYNOPSIS
+
+ nbdkit --filter=extentlist plugin extentlist=FILENAME
+
+=head1 DESCRIPTION
+
+C<nbdkit-extentlist-filter> is an nbdkit filter lets you place a
+static list of extents on top of an existing plugin. Extents record
+whether or not specific parts of the disk are allocated or sparse.
+
+You can use this with plugins which cannot get extent information
+themselves, but you can get this information from another source. One
+place where it is useful is with L<nbdkit-ssh-plugin(1)> because the
+sftp protocol does not support reading sparseness information, but you
+may be able to get this information directly from the source disk on
+the remote server.
+
+=head1 FILE FORMAT
+
+The list of extents is specified in a text file. There is one extent
+specified per line. Each line has the format:
+
+ offset length type
+
+The C<offset> and C<length> fields may use any format understood by
+C<nbdkit_parse_size>. The optional C<type> field may be an integer,
+missing (same as 0), or a comma-separated list of the words C<hole>
+and C<zero>. (The fields correspond to the inputs of the
+C<nbdkit_add_extent> function, see L<nbdkit-plugin(3)>).
+
+An example of a valid set of extents covering a C<10M> disk where the
+first megabyte only is allocated data:
+
+ 0 1M
+ 1M 9M hole,zero
+
+Or you could omit the C<hole,zero> extent since any gaps are assumed
+to be holes with that type:
+
+ 0 1M
+
+The extent list need not cover the whole disk, and does not need to be
+in ascending order, but it must I<not> contain overlapping extents.
+
+=head1 PARAMETERS
+
+=over 4
+
+=item B<extentlist=>FILENAME
+
+Specify the file containing the extent list, in the format described
+in L</FILE FORMAT> above.
+
+=back
+
+=head1 FILES
+
+=over 4
+
+=item F<$filterdir/nbdkit-extentlist-filter.so>
+
+The filter.
+
+Use C<nbdkit --dump-config> to find the location of C<$filterdir>.
+
+=back
+
+=head1 VERSION
+
+C<nbdkit-extentlist-filter> first appeared in nbdkit 1.18.
+
+=head1 SEE ALSO
+
+L<nbdkit(1)>,
+L<nbdkit-cacheextents-filter(1)>,
+L<nbdkit-noextents-filter(1)>,
+L<nbdkit-filter(3)>,
+L<nbdkit-plugin(3)>.
+
+=head1 AUTHORS
+
+Richard W.M. Jones
+
+=head1 COPYRIGHT
+
+Copyright (C) 2020 Red Hat Inc.
diff --git a/filters/noextents/nbdkit-noextents-filter.pod b/filters/noextents/nbdkit-noextents-filter.pod
index 991ecfe8..0260a5cf 100644
--- a/filters/noextents/nbdkit-noextents-filter.pod
+++ b/filters/noextents/nbdkit-noextents-filter.pod
@@ -47,6 +47,7 @@ C<nbdkit-noextents-filter> first appeared in nbdkit 1.14.
L<nbdkit(1)>,
L<nbdkit-filter(3)>,
+L<nbdkit-extentlist-filter(1)>,
L<nbdkit-fua-filter(1)>,
L<nbdkit-nocache-filter(1)>,
L<nbdkit-noparallel-filter(1)>,
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 09103fbb..b99952f4 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -110,6 +110,7 @@ EXTRA_DIST = \
test-error100.sh \
test-error-triggered.sh \
test-export-name.sh \
+ test-extentlist.sh \
test-file-extents.sh \
test-floppy.sh \
test-foreground.sh \
@@ -1009,6 +1010,9 @@ TESTS += \
test-error-triggered.sh \
$(NULL)
+# extentlist filter test.
+TESTS += test-extentlist.sh
+
# fua filter test.
TESTS += test-fua.sh
diff --git a/tests/test-extentlist.sh b/tests/test-extentlist.sh
new file mode 100755
index 00000000..7d05de4f
--- /dev/null
+++ b/tests/test-extentlist.sh
@@ -0,0 +1,175 @@
+#!/usr/bin/env bash
+# nbdkit
+# Copyright (C) 2016-2020 Red Hat Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+#
+# * Neither the name of Red Hat nor the names of its contributors may be
+# used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+# Test the extentlist filter.
+
+source ./functions.sh
+set -e
+set -x
+
+requires jq --version
+requires qemu-img --version
+requires qemu-img map --help
+
+out=test-extentlist.out
+input=test-extentlist.in
+expected=test-extentlist.expected
+files="$out $input $expected"
+rm -f $files
+cleanup_fn rm $files
+
+test ()
+{
+ nbdkit -v -D extentlist.lookup=1 \
+ -U - \
+ --filter=extentlist \
+ null size=$1 extentlist=$input \
+ --run 'qemu-img map -f raw --output=json $nbd' |
+ jq -c '.[] | {start:.start, length:.length, data:.data, zero:.zero}' \
+ > $out
+ diff -u $out $expected
+}
+
+# Empty extent list.
+cat > $input <<'EOF'
+EOF
+
+cat > $expected <<'EOF'
+{"start":0,"length":0,"data":false,"zero":false}
+EOF
+test 0
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+EOF
+test 1M
+
+# Extent list covering 0-1M with data.
+cat > $input <<'EOF'
+0 1M
+EOF
+
+cat > $expected <<'EOF'
+{"start":0,"length":0,"data":false,"zero":false}
+EOF
+test 0
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":true,"zero":false}
+EOF
+test 1M
+
+# Extent list covering 1-2M with data.
+cat > $input <<'EOF'
+1M 1M
+EOF
+
+cat > $expected <<'EOF'
+{"start":0,"length":0,"data":false,"zero":false}
+EOF
+test 0
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+EOF
+test 1M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+{"start":1048576,"length":1048576,"data":true,"zero":false}
+EOF
+test 2M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+{"start":1048576,"length":1048576,"data":true,"zero":false}
+{"start":2097152,"length":1048576,"data":false,"zero":true}
+EOF
+test 3M
+
+# Extent list covering 1-2M with data, but in a more fragmented
+# way than the above.
+cat > $input <<'EOF'
+1024K 512K
+1536K 512K
+EOF
+
+cat > $expected <<'EOF'
+{"start":0,"length":0,"data":false,"zero":false}
+EOF
+test 0
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+EOF
+test 1M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+{"start":1048576,"length":1048576,"data":true,"zero":false}
+EOF
+test 2M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":false,"zero":true}
+{"start":1048576,"length":1048576,"data":true,"zero":false}
+{"start":2097152,"length":1048576,"data":false,"zero":true}
+EOF
+test 3M
+
+# Adjacent data and holes.
+cat > $input <<'EOF'
+0 1M
+2M 1M
+4M 1M
+EOF
+
+cat > $expected <<'EOF'
+{"start":0,"length":0,"data":false,"zero":false}
+EOF
+test 0
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":true,"zero":false}
+EOF
+test 1M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":true,"zero":false}
+{"start":1048576,"length":1048576,"data":false,"zero":true}
+EOF
+test 2M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":true,"zero":false}
+{"start":1048576,"length":1048576,"data":false,"zero":true}
+{"start":2097152,"length":1048576,"data":true,"zero":false}
+EOF
+test 3M
+cat > $expected <<'EOF'
+{"start":0,"length":1048576,"data":true,"zero":false}
+{"start":1048576,"length":1048576,"data":false,"zero":true}
+{"start":2097152,"length":1048576,"data":true,"zero":false}
+{"start":3145728,"length":1048576,"data":false,"zero":true}
+{"start":4194304,"length":1048576,"data":true,"zero":false}
+{"start":5242880,"length":1048576,"data":false,"zero":true}
+EOF
+test 6M
--
2.18.2