From 6e6e55f5c2e5b520d6506c2716287ba3b5d1bbc8 Mon Sep 17 00:00:00 2001 From: John Snow Date: Mon, 17 Jul 2017 20:34:22 -0400 Subject: [PATCH] qemu-img: Check for backing image if specified during create Or, rather, force the open of a backing image if one was specified for creation. Using a similar -unsafe option as rebase, allow qemu-img to ignore the backing file validation if possible. It may not always be possible, as in the existing case when a filesize for the new image was not specified. This is accomplished by shifting around the conditionals in bdrv_img_create, such that a backing file is always opened unless we provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag when -u is provided to create. Sorry for the heinous looking diffstat, but it's mostly whitespace. Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786 Signed-off-by: John Snow Signed-off-by: Kevin Wolf --- block.c | 94 +++++++++++++++++++++----------------- qemu-img-cmds.hx | 4 +- qemu-img.c | 16 +++++-- qemu-img.texi | 9 +++- tests/qemu-iotests/082 | 4 +- tests/qemu-iotests/082.out | 4 +- tests/qemu-iotests/085 | 2 +- tests/qemu-iotests/111.out | 1 + tests/qemu-iotests/139 | 2 +- tests/qemu-iotests/156 | 2 +- tests/qemu-iotests/158 | 2 +- tests/qemu-iotests/189 | 2 +- 12 files changed, 83 insertions(+), 59 deletions(-) diff --git a/block.c b/block.c index 98a9209371..2dd9262cd0 100644 --- a/block.c +++ b/block.c @@ -4396,55 +4396,65 @@ void bdrv_img_create(const char *filename, const char *fmt, backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); - // The size for the image must always be specified, with one exception: - // If we are using a backing file, we can obtain the size from there + /* The size for the image must always be specified, unless we have a backing + * file and we have not been forbidden from opening it. */ size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); - if (size == -1) { - if (backing_file) { - BlockDriverState *bs; - char *full_backing = g_new0(char, PATH_MAX); - int64_t size; - int back_flags; - QDict *backing_options = NULL; - - bdrv_get_full_backing_filename_from_filename(filename, backing_file, - full_backing, PATH_MAX, - &local_err); - if (local_err) { - g_free(full_backing); - goto out; - } + if (backing_file && !(flags & BDRV_O_NO_BACKING)) { + BlockDriverState *bs; + char *full_backing = g_new0(char, PATH_MAX); + int back_flags; + QDict *backing_options = NULL; + + bdrv_get_full_backing_filename_from_filename(filename, backing_file, + full_backing, PATH_MAX, + &local_err); + if (local_err) { + g_free(full_backing); + goto out; + } - /* backing files always opened read-only */ - back_flags = flags; - back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); + /* backing files always opened read-only */ + back_flags = flags; + back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); - if (backing_fmt) { - backing_options = qdict_new(); - qdict_put_str(backing_options, "driver", backing_fmt); - } + if (backing_fmt) { + backing_options = qdict_new(); + qdict_put_str(backing_options, "driver", backing_fmt); + } - bs = bdrv_open(full_backing, NULL, backing_options, back_flags, - &local_err); - g_free(full_backing); - if (!bs) { - goto out; - } - size = bdrv_getlength(bs); - if (size < 0) { - error_setg_errno(errp, -size, "Could not get size of '%s'", - backing_file); - bdrv_unref(bs); - goto out; + bs = bdrv_open(full_backing, NULL, backing_options, back_flags, + &local_err); + g_free(full_backing); + if (!bs && size != -1) { + /* Couldn't open BS, but we have a size, so it's nonfatal */ + warn_reportf_err(local_err, + "Could not verify backing image. " + "This may become an error in future versions.\n"); + local_err = NULL; + } else if (!bs) { + /* Couldn't open bs, do not have size */ + error_append_hint(&local_err, + "Could not open backing image to determine size.\n"); + goto out; + } else { + if (size == -1) { + /* Opened BS, have no size */ + size = bdrv_getlength(bs); + if (size < 0) { + error_setg_errno(errp, -size, "Could not get size of '%s'", + backing_file); + bdrv_unref(bs); + goto out; + } + qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort); } - - qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort); - bdrv_unref(bs); - } else { - error_setg(errp, "Image creation needs a size parameter"); - goto out; } + } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */ + + if (size == -1) { + error_setg(errp, "Image creation needs a size parameter"); + goto out; } if (!quiet) { diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx index ac5946bc4f..3763f13625 100644 --- a/qemu-img-cmds.hx +++ b/qemu-img-cmds.hx @@ -22,9 +22,9 @@ STEXI ETEXI DEF("create", img_create, - "create [-q] [--object objectdef] [-f fmt] [-b backing_file] [-F backing_fmt] [-o options] filename [size]") + "create [-q] [--object objectdef] [-f fmt] [-b backing_file] [-F backing_fmt] [-u] [-o options] filename [size]") STEXI -@item create [--object @var{objectdef}] [-q] [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-o @var{options}] @var{filename} [@var{size}] +@item create [--object @var{objectdef}] [-q] [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-u] [-o @var{options}] @var{filename} [@var{size}] ETEXI DEF("commit", img_commit, diff --git a/qemu-img.c b/qemu-img.c index 182e697f81..eb32b93e90 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -150,9 +150,11 @@ static void QEMU_NORETURN help(void) " 'snapshot_id_or_name' is deprecated, use 'snapshot_param'\n" " instead\n" " '-c' indicates that target image must be compressed (qcow format only)\n" - " '-u' enables unsafe rebasing. It is assumed that old and new backing file\n" - " match exactly. The image doesn't need a working backing file before\n" - " rebasing in this case (useful for renaming the backing file)\n" + " '-u' allows unsafe backing chains. For rebasing, it is assumed that old and\n" + " new backing file match exactly. The image doesn't need a working\n" + " backing file before rebasing in this case (useful for renaming the\n" + " backing file). For image creation, allow creating without attempting\n" + " to open the backing file.\n" " '-h' with or without a command shows this help and lists the supported formats\n" " '-p' show progress of command (only certain commands)\n" " '-q' use Quiet mode - do not print any output (except errors)\n" @@ -429,6 +431,7 @@ static int img_create(int argc, char **argv) char *options = NULL; Error *local_err = NULL; bool quiet = false; + int flags = 0; for(;;) { static const struct option long_options[] = { @@ -436,7 +439,7 @@ static int img_create(int argc, char **argv) {"object", required_argument, 0, OPTION_OBJECT}, {0, 0, 0, 0} }; - c = getopt_long(argc, argv, ":F:b:f:ho:q", + c = getopt_long(argc, argv, ":F:b:f:ho:qu", long_options, NULL); if (c == -1) { break; @@ -476,6 +479,9 @@ static int img_create(int argc, char **argv) case 'q': quiet = true; break; + case 'u': + flags |= BDRV_O_NO_BACKING; + break; case OPTION_OBJECT: { QemuOpts *opts; opts = qemu_opts_parse_noisily(&qemu_object_opts, @@ -528,7 +534,7 @@ static int img_create(int argc, char **argv) } bdrv_img_create(filename, fmt, base_filename, base_fmt, - options, img_size, 0, quiet, &local_err); + options, img_size, flags, quiet, &local_err); if (local_err) { error_reportf_err(local_err, "%s: ", filename); goto fail; diff --git a/qemu-img.texi b/qemu-img.texi index f11f6036ad..72dabd6b3e 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -233,7 +233,7 @@ If @code{-r} is specified, exit codes representing the image state refer to the state after (the attempt at) repairing it. That is, a successful @code{-r all} will yield the exit code 0, independently of the image state before. -@item create [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-o @var{options}] @var{filename} [@var{size}] +@item create [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-u] [-o @var{options}] @var{filename} [@var{size}] Create the new disk image @var{filename} of size @var{size} and format @var{fmt}. Depending on the file format, you can add one or more @var{options} @@ -244,6 +244,13 @@ only the differences from @var{backing_file}. No size needs to be specified in this case. @var{backing_file} will never be modified unless you use the @code{commit} monitor command (or qemu-img commit). +Note that a given backing file will be opened to check that it is valid. Use +the @code{-u} option to enable unsafe backing file mode, which means that the +image will be created even if the associated backing file cannot be opened. A +matching backing file must be created or additional options be used to make the +backing file specification valid when you want to use an image created this +way. + The size can also be specified using the @var{size} option with @code{-o}, it doesn't need to be specified separately in this case. diff --git a/tests/qemu-iotests/082 b/tests/qemu-iotests/082 index ad1d9fadc1..d5c83d45ed 100755 --- a/tests/qemu-iotests/082 +++ b/tests/qemu-iotests/082 @@ -85,8 +85,8 @@ run_qemu_img create -f $IMGFMT -o cluster_size=4k -o help "$TEST_IMG" $size run_qemu_img create -f $IMGFMT -o cluster_size=4k -o \? "$TEST_IMG" $size # Looks like a help option, but is part of the backing file name -run_qemu_img create -f $IMGFMT -o backing_file="$TEST_IMG",,help "$TEST_IMG" $size -run_qemu_img create -f $IMGFMT -o backing_file="$TEST_IMG",,\? "$TEST_IMG" $size +run_qemu_img create -f $IMGFMT -u -o backing_file="$TEST_IMG",,help "$TEST_IMG" $size +run_qemu_img create -f $IMGFMT -u -o backing_file="$TEST_IMG",,\? "$TEST_IMG" $size # Try to trick qemu-img into creating escaped commas run_qemu_img create -f $IMGFMT -o backing_file="$TEST_IMG", -o help "$TEST_IMG" $size diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out index dbed67f2ba..1527fbe1b7 100644 --- a/tests/qemu-iotests/082.out +++ b/tests/qemu-iotests/082.out @@ -210,10 +210,10 @@ lazy_refcounts Postpone refcount updates refcount_bits Width of a reference count entry in bits nocow Turn off copy-on-write (valid only on btrfs) -Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M +Testing: create -f qcow2 -u -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file=TEST_DIR/t.qcow2,,help cluster_size=65536 lazy_refcounts=off refcount_bits=16 -Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,? TEST_DIR/t.qcow2 128M +Testing: create -f qcow2 -u -o backing_file=TEST_DIR/t.qcow2,,? TEST_DIR/t.qcow2 128M Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file=TEST_DIR/t.qcow2,,? cluster_size=65536 lazy_refcounts=off refcount_bits=16 Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2, -o help TEST_DIR/t.qcow2 128M diff --git a/tests/qemu-iotests/085 b/tests/qemu-iotests/085 index b97adcd8db..71efe50d34 100755 --- a/tests/qemu-iotests/085 +++ b/tests/qemu-iotests/085 @@ -104,7 +104,7 @@ function add_snapshot_image() { base_image="${TEST_DIR}/$((${1}-1))-${snapshot_virt0}" snapshot_file="${TEST_DIR}/${1}-${snapshot_virt0}" - _make_test_img -b "${base_image}" "$size" + _make_test_img -u -b "${base_image}" "$size" mv "${TEST_IMG}" "${snapshot_file}" do_blockdev_add "$1" "'backing': '', " "${snapshot_file}" } diff --git a/tests/qemu-iotests/111.out b/tests/qemu-iotests/111.out index 683c01a679..5279c462fc 100644 --- a/tests/qemu-iotests/111.out +++ b/tests/qemu-iotests/111.out @@ -1,3 +1,4 @@ QA output created by 111 qemu-img: TEST_DIR/t.IMGFMT: Could not open 'TEST_DIR/t.IMGFMT.inexistent': No such file or directory +Could not open backing image to determine size. *** done diff --git a/tests/qemu-iotests/139 b/tests/qemu-iotests/139 index 175d8f0008..9ff51d9647 100644 --- a/tests/qemu-iotests/139 +++ b/tests/qemu-iotests/139 @@ -65,7 +65,7 @@ class TestBlockdevDel(iotests.QMPTestCase): # Add a BlockDriverState that will be used as overlay for the base_img BDS def addBlockDriverStateOverlay(self, node): self.checkBlockDriverState(node, False) - iotests.qemu_img('create', '-f', iotests.imgfmt, + iotests.qemu_img('create', '-u', '-f', iotests.imgfmt, '-b', base_img, new_img, '1M') opts = {'driver': iotests.imgfmt, 'node-name': node, diff --git a/tests/qemu-iotests/156 b/tests/qemu-iotests/156 index d799b73e1e..2c4a06e2d8 100755 --- a/tests/qemu-iotests/156 +++ b/tests/qemu-iotests/156 @@ -66,7 +66,7 @@ _send_qemu_cmd $QEMU_HANDLE \ 'return' # Create snapshot -TEST_IMG="$TEST_IMG.overlay" _make_test_img -b "$TEST_IMG" 1M +TEST_IMG="$TEST_IMG.overlay" _make_test_img -u -b "$TEST_IMG" 1M _send_qemu_cmd $QEMU_HANDLE \ "{ 'execute': 'blockdev-snapshot-sync', 'arguments': { 'device': 'source', diff --git a/tests/qemu-iotests/158 b/tests/qemu-iotests/158 index 823c12002e..24ac600a4a 100755 --- a/tests/qemu-iotests/158 +++ b/tests/qemu-iotests/158 @@ -66,7 +66,7 @@ echo "== verify pattern ==" $QEMU_IO --object $SECRET -c "read -P 0xa 0 $size" --image-opts $IMGSPECBASE | _filter_qemu_io | _filter_testdir echo "== create overlay ==" -_make_test_img --object $SECRET -o "encryption=on,encrypt.key-secret=sec0" -b "$TEST_IMG_BASE" $size +_make_test_img -u --object $SECRET -o "encryption=on,encrypt.key-secret=sec0" -b "$TEST_IMG_BASE" $size echo echo "== writing part of a cluster ==" diff --git a/tests/qemu-iotests/189 b/tests/qemu-iotests/189 index 54ad980a4e..e695475722 100755 --- a/tests/qemu-iotests/189 +++ b/tests/qemu-iotests/189 @@ -66,7 +66,7 @@ echo "== verify pattern ==" $QEMU_IO --object $SECRET0 -c "read -P 0xa 0 $size" --image-opts $IMGSPECBASE | _filter_qemu_io | _filter_testdir echo "== create overlay ==" -_make_test_img --object $SECRET1 -o "encrypt.format=luks,encrypt.key-secret=sec1,encrypt.iter-time=10" -b "$TEST_IMG_BASE" $size +_make_test_img --object $SECRET1 -o "encrypt.format=luks,encrypt.key-secret=sec1,encrypt.iter-time=10" -u -b "$TEST_IMG_BASE" $size echo echo "== writing part of a cluster ==" -- GitLab