From c0469496b32910a6a092d5b614efbf4088b13a29 Mon Sep 17 00:00:00 2001 From: Eyal Moscovici Date: Wed, 13 May 2020 16:36:29 +0300 Subject: [PATCH] qemu-img: Add --start-offset and --max-length to map The mapping operation of large disks especially ones stored over a long chain of QCOW2 files can take a long time to finish. Additionally when mapping fails there was no way recover by restarting the mapping from the failed location. The new options, --start-offset and --max-length allows the user to divide these type of map operations into shorter independent tasks. Reviewed-by: Eric Blake Acked-by: Mark Kanda Co-developed-by: Yoav Elnekave Signed-off-by: Yoav Elnekave Signed-off-by: Eyal Moscovici Message-Id: <20200513133629.18508-5-eyal.moscovici@oracle.com> Signed-off-by: Eric Blake --- docs/tools/qemu-img.rst | 2 +- qemu-img-cmds.hx | 4 ++-- qemu-img.c | 22 +++++++++++++++++++++- 3 files changed, 24 insertions(+), 4 deletions(-) diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst index 0080f83a76..f4ffe528ea 100644 --- a/docs/tools/qemu-img.rst +++ b/docs/tools/qemu-img.rst @@ -519,7 +519,7 @@ Command description: ``ImageInfoSpecific*`` QAPI object (e.g. ``ImageInfoSpecificQCow2`` for qcow2 images). -.. option:: map [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [-U] FILENAME +.. option:: map [--object OBJECTDEF] [--image-opts] [-f FMT] [--start-offset=OFFSET] [--max-length=LEN] [--output=OFMT] [-U] FILENAME Dump the metadata of image *FILENAME* and its backing file chain. In particular, this commands dumps the allocation state of every sector diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx index c9c54de1df..35f832816f 100644 --- a/qemu-img-cmds.hx +++ b/qemu-img-cmds.hx @@ -63,9 +63,9 @@ SRST ERST DEF("map", img_map, - "map [--object objectdef] [--image-opts] [-f fmt] [--output=ofmt] [-U] filename") + "map [--object objectdef] [--image-opts] [-f fmt] [--start-offset=offset] [--max-length=len] [--output=ofmt] [-U] filename") SRST -.. option:: map [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [-U] FILENAME +.. option:: map [--object OBJECTDEF] [--image-opts] [-f FMT] [--start-offset=OFFSET] [--max-length=LEN] [--output=OFMT] [-U] FILENAME ERST DEF("measure", img_measure, diff --git a/qemu-img.c b/qemu-img.c index 4aa9414aba..947bf8b34b 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3009,6 +3009,8 @@ static int img_map(int argc, char **argv) int ret = 0; bool image_opts = false; bool force_share = false; + int64_t start_offset = 0; + int64_t max_length = -1; fmt = NULL; output = NULL; @@ -3021,9 +3023,11 @@ static int img_map(int argc, char **argv) {"object", required_argument, 0, OPTION_OBJECT}, {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS}, {"force-share", no_argument, 0, 'U'}, + {"start-offset", required_argument, 0, 's'}, + {"max-length", required_argument, 0, 'l'}, {0, 0, 0, 0} }; - c = getopt_long(argc, argv, ":f:hU", + c = getopt_long(argc, argv, ":f:s:l:hU", long_options, &option_index); if (c == -1) { break; @@ -3047,6 +3051,18 @@ static int img_map(int argc, char **argv) case OPTION_OUTPUT: output = optarg; break; + case 's': + start_offset = cvtnum("start offset", optarg); + if (start_offset < 0) { + return 1; + } + break; + case 'l': + max_length = cvtnum("max length", optarg); + if (max_length < 0) { + return 1; + } + break; case OPTION_OBJECT: { QemuOpts *opts; opts = qemu_opts_parse_noisily(&qemu_object_opts, @@ -3097,7 +3113,11 @@ static int img_map(int argc, char **argv) error_report("Failed to get size for '%s'", filename); return 1; } + if (max_length != -1) { + length = MIN(start_offset + max_length, length); + } + curr.start = start_offset; while (curr.start + curr.length < length) { int64_t offset = curr.start + curr.length; int64_t n;