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[PATCH 2/2] qemu-img: Add --start-offset and --max-length to map
From: |
Eyal Moscovici |
Subject: |
[PATCH 2/2] qemu-img: Add --start-offset and --max-length to map |
Date: |
Sun, 22 Mar 2020 11:11:17 +0200 |
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.
Acked-by: Mark Kanda <address@hidden>
Co-developed-by: Yoav Elnekave <address@hidden>
Signed-off-by: Yoav Elnekave <address@hidden>
Signed-off-by: Eyal Moscovici <address@hidden>
---
docs/tools/qemu-img.rst | 2 +-
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 30 +++++++++++++++++++++++++++++-
3 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 0080f83a76..924e89f679 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 9cf8576217..cd365b275e 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2967,6 +2967,8 @@ 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;
@@ -2979,9 +2981,11 @@ 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;
@@ -3005,6 +3009,26 @@ static int img_map(int argc, char **argv)
case OPTION_OUTPUT:
output = optarg;
break;
+ case 's':
+ start_offset = cvtnum(optarg);
+ if (start_offset < 0) {
+ error_report("Invalid start offset specified! You may use "
+ "k, M, G, T, P or E suffixes for ");
+ error_report("kilobytes, megabytes, gigabytes, terabytes, "
+ "petabytes and exabytes.");
+ return 1;
+ }
+ break;
+ case 'l':
+ max_length = cvtnum(optarg);
+ if (max_length < 0) {
+ error_report("Invalid max length specified! You may use "
+ "k, M, G, T, P or E suffixes for ");
+ error_report("kilobytes, megabytes, gigabytes, terabytes, "
+ "petabytes and exabytes.");
+ return 1;
+ }
+ break;
case OPTION_OBJECT: {
QemuOpts *opts;
opts = qemu_opts_parse_noisily(&qemu_object_opts,
@@ -3050,7 +3074,11 @@ static int img_map(int argc, char **argv)
printf("[");
}
+ curr.start = start_offset;
length = blk_getlength(blk);
+ if (max_length != -1) {
+ length = MIN(start_offset + max_length, length);
+ }
while (curr.start + curr.length < length) {
int64_t offset = curr.start + curr.length;
int64_t n;
--
2.17.2 (Apple Git-113)