This is second version of patch adding compare subcommand that
compares two
images. Compare has following criteria:
- only data part is compared
- unallocated sectors are not read
- in case of different image size, exceeding part of bigger disk has
to be zeroed/unallocated to compare rest
- qemu-img returns:
- 0 if images are identical
- 1 if images differ
- 2 on error
v3:
- options -f/-F are orthogonal
- documentation updated to new syntax and behavior
- used byte offset instead of sector number for output
v2:
- changed option for second image format to -F
- changed handlig of -f and -F [1]
- added strict mode (-s)
- added quiet mode (-q)
- improved output messages [2]
- rename variables for larger image handling
- added man page content
Signed-off-by: Miroslav Rezanina
diff --git a/block.c b/block.c
index 854ebd6..fdc8c45 100644
--- a/block.c
+++ b/block.c
@@ -2698,6 +2698,7 @@ int bdrv_has_zero_init(BlockDriverState *bs)
typedef struct BdrvCoIsAllocatedData {
BlockDriverState *bs;
+BlockDriverState *base;
int64_t sector_num;
int nb_sectors;
int *pnum;
@@ -2828,6 +2829,44 @@ int coroutine_fn
bdrv_co_is_allocated_above(BlockDriverState *top,
return 0;
}
+/* Coroutine wrapper for bdrv_is_allocated_above() */
+static void coroutine_fn bdrv_is_allocated_above_co_entry(void *opaque)
+{
+BdrvCoIsAllocatedData *data = opaque;
+BlockDriverState *top = data-bs;
+BlockDriverState *base = data-base;
+
+data-ret = bdrv_co_is_allocated_above(top, base, data-sector_num,
+ data-nb_sectors, data-pnum);
+data-done = true;
+}
+
+/*
+ * Synchronous wrapper around bdrv_co_is_allocated_above().
+ *
+ * See bdrv_co_is_allocated_above() for details.
+ */
+int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
+ int64_t sector_num, int nb_sectors, int *pnum)
+{
+Coroutine *co;
+BdrvCoIsAllocatedData data = {
+.bs = top,
+.base = base,
+.sector_num = sector_num,
+.nb_sectors = nb_sectors,
+.pnum = pnum,
+.done = false,
+};
+
+co = qemu_coroutine_create(bdrv_is_allocated_above_co_entry);
+qemu_coroutine_enter(co, data);
+while (!data.done) {
+qemu_aio_wait();
+}
+return data.ret;
+}
+
BlockInfo *bdrv_query_info(BlockDriverState *bs)
{
BlockInfo *info = g_malloc0(sizeof(*info));
diff --git a/block.h b/block.h
index 722c620..2cb8d71 100644
--- a/block.h
+++ b/block.h
@@ -278,6 +278,8 @@ int bdrv_co_discard(BlockDriverState *bs, int64_t
sector_num, int nb_sectors);
int bdrv_has_zero_init(BlockDriverState *bs);
int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
int *pnum);
+int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
+int64_t sector_num, int nb_sectors, int *pnum);
void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error,
BlockdevOnError on_write_error);
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index a181363..c076085 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -27,6 +27,12 @@ STEXI
@item commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
ETEXI
+DEF(compare, img_compare,
+compare [-f fmt] [-F fmt] [-p] [-q] [-s] filename1 filename2)
+STEXI
+@item compare [-f @var{fmt}] [-F @var{fmt}] [-p] [-q] [-s] @var{filename1}
@var{filename2}
+ETEXI
+
DEF(convert, img_convert,
convert [-c] [-p] [-f fmt] [-t cache] [-O output_fmt] [-o options] [-s
snapshot_name] [-S sparse_size] filename [filename2 [...]] output_filename)
STEXI
diff --git a/qemu-img.c b/qemu-img.c
index e29e01b..6294b11 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -101,7 +101,12 @@ static void help(void)
'-a' applies a snapshot (revert disk to saved state)\n
'-c' creates a snapshot\n
'-d' deletes a snapshot\n
- '-l' lists all snapshots in the given image\n;
+ '-l' lists all snapshots in the given image\n
+ Parameters to compare subcommand:\n
+ '-f' First image format\n
+ '-F' Second image format\n
+ '-q' Quiet mode - do not print any output (except errors)\n
+ '-s' Strict mode - fail on different image size or sector
allocation\n;
printf(%s\nSupported formats:, help_msg);
bdrv_iterate_format(format_print, NULL);
@@ -657,6 +662,277 @@ static int compare_sectors(const uint8_t *buf1, const
uint8_t *buf2, int n,
}
#define IO_BUF_SIZE (2 * 1024 * 1024)
+#define sector_to_bytes(sector) ((sector) BDRV_SECTOR_BITS)
+
+/*
+ * Get number of sectors that can be stored in IO buffer.
+ */
+
+static int64_t sectors_to_process(int64_t total, int64_t from)
+{
+int64_t rv = total - from;
+
+if (rv (IO_BUF_SIZE BDRV_SECTOR_BITS)) {
+return IO_BUF_SIZE BDRV_SECTOR_BITS;
+}
+
+
