diff mbox series

[v2,3/4] qemu-img: add --shallow option for qemu-img compare

Message ID 20211021101236.1144824-4-vsementsov@virtuozzo.com (mailing list archive)
State New, archived
Headers show
Series qemu-img compare --stat | expand

Commit Message

Vladimir Sementsov-Ogievskiy Oct. 21, 2021, 10:12 a.m. UTC 
Allow compare only top images of backing chains. This is useful to
compare images with same backing file or to compare incremental images
from the chain of incremental backups with "--stat" option.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 docs/tools/qemu-img.rst | 9 ++++++++-
 qemu-img.c              | 8 ++++++--
 qemu-img-cmds.hx        | 4 ++--
 3 files changed, 16 insertions(+), 5 deletions(-)

Comments

Hanna Czenczek Oct. 26, 2021, 8:11 a.m. UTC | #1 
On 21.10.21 12:12, Vladimir Sementsov-Ogievskiy wrote:
> Allow compare only top images of backing chains. This is useful to
> compare images with same backing file or to compare incremental images
> from the chain of incremental backups with "--stat" option.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   docs/tools/qemu-img.rst | 9 ++++++++-
>   qemu-img.c              | 8 ++++++--
>   qemu-img-cmds.hx        | 4 ++--
>   3 files changed, 16 insertions(+), 5 deletions(-)

Reviewed-by: Hanna Reitz <hreitz@redhat.com>
diff mbox series

Patch

diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index 4b382ca2b0..4ae9543472 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -176,6 +176,13 @@  Parameters to compare subcommand:
     - If both files don't specify cluster-size, use default of 64K
     - If only one file specify cluster-size, just use it.
 
+.. option:: --shallow
+
+  This option prevents opening and comparing any backing files.
+  This is useful to compare images with same backing file or to compare
+  incremental images from the chain of incremental backups with
+  ``--stat`` option.
+
 Parameters to convert subcommand:
 
 .. program:: qemu-img-convert
@@ -395,7 +402,7 @@  Command description:
 
   The rate limit for the commit process is specified by ``-r``.
 
-.. option:: compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] [--stat [--block-size BLOCK_SIZE]] FILENAME1 FILENAME2
+.. option:: compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] [--stat [--block-size BLOCK_SIZE]] [--shallow] FILENAME1 FILENAME2
 
   Check if two images have the same content. You can compare images with
   different format or settings.
diff --git a/qemu-img.c b/qemu-img.c
index 61e7f470bb..c9b5067353 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -85,6 +85,7 @@  enum {
     OPTION_SKIP_BROKEN = 277,
     OPTION_STAT = 277,
     OPTION_BLOCK_SIZE = 278,
+    OPTION_SHALLOW = 279,
 };
 
 typedef enum OutputFormat {
@@ -1482,7 +1483,7 @@  static int img_compare(int argc, char **argv)
     int64_t block_end;
     int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */
     bool progress = false, quiet = false, strict = false;
-    int flags;
+    int flags = 0;
     bool writethrough;
     int64_t total_size;
     int64_t offset = 0;
@@ -1504,6 +1505,7 @@  static int img_compare(int argc, char **argv)
             {"force-share", no_argument, 0, 'U'},
             {"stat", no_argument, 0, OPTION_STAT},
             {"block-size", required_argument, 0, OPTION_BLOCK_SIZE},
+            {"shallow", no_argument, 0, OPTION_SHALLOW},
             {0, 0, 0, 0}
         };
         c = getopt_long(argc, argv, ":hf:F:T:pqsU",
@@ -1569,6 +1571,9 @@  static int img_compare(int argc, char **argv)
                 exit(EXIT_SUCCESS);
             }
             break;
+        case OPTION_SHALLOW:
+            flags |= BDRV_O_NO_BACKING;
+            break;
         }
     }
 
@@ -1593,7 +1598,6 @@  static int img_compare(int argc, char **argv)
     /* Initialize before goto out */
     qemu_progress_init(progress, 2.0);
 
-    flags = 0;
     ret = bdrv_parse_cache_mode(cache, &flags, &writethrough);
     if (ret < 0) {
         error_report("Invalid source cache option: %s", cache);
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 96a193eea8..6b164767fd 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -40,9 +40,9 @@  SRST
 ERST
 
 DEF("compare", img_compare,
-    "compare [--object objectdef] [--image-opts] [-f fmt] [-F fmt] [-T src_cache] [-p] [-q] [-s] [-U] [--stat [--block-size BLOCK_SIZE]] filename1 filename2")
+    "compare [--object objectdef] [--image-opts] [-f fmt] [-F fmt] [-T src_cache] [-p] [-q] [-s] [-U] [--stat [--block-size BLOCK_SIZE]] [--shallow] filename1 filename2")
 SRST
-.. option:: compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] [--stat [--block-size BLOCK_SIZE]] FILENAME1 FILENAME2
+.. option:: compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] [--stat [--block-size BLOCK_SIZE]] [--shallow] FILENAME1 FILENAME2
 ERST
 
 DEF("convert", img_convert,