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bitmap: Enforce maximum bitmap name length

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We document that for qcow2 persistent bitmaps, the name cannot exceed
1023 bytes.  It is inconsistent if transient bitmaps do not have to
abide by the same limit, and it is unlikely that any existing client
even cares about using bitmap names this long.  It's time to codify
that ALL bitmaps managed by qemu (whether persistent in qcow2 or not)
have a documented maximum length.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20191114024635.11363-3-eblake@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This commit is contained in:
Eric Blake 2019-11-13 20:46:33 -06:00
parent 9d7ab222da
commit cf7c49cf6a
4 changed files with 14 additions and 4 deletions
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8
block/dirty-bitmap.c
View File

@ -104,10 +104,16 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
assert(is_power_of_2(granularity) && granularity >= BDRV_SECTOR_SIZE);
if (name && bdrv_find_dirty_bitmap(bs, name)) {
if (name) {
if (bdrv_find_dirty_bitmap(bs, name)) {
error_setg(errp, "Bitmap already exists: %s", name);
return NULL;
}
if (strlen(name) > BDRV_BITMAP_MAX_NAME_SIZE) {
error_setg(errp, "Bitmap name too long: %s", name);
return NULL;
}
}
bitmap_size = bdrv_getlength(bs);
if (bitmap_size < 0) {
error_setg_errno(errp, -bitmap_size, "could not get length of device");

2
block/qcow2-bitmap.c
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@ -42,6 +42,8 @@
#define BME_MIN_GRANULARITY_BITS 9
#define BME_MAX_NAME_SIZE 1023
QEMU_BUILD_BUG_ON(BME_MAX_NAME_SIZE != BDRV_BITMAP_MAX_NAME_SIZE);
#if BME_MAX_TABLE_SIZE * 8ULL > INT_MAX
#error In the code bitmap table physical size assumed to fit into int
#endif

2
include/block/dirty-bitmap.h
View File

@ -14,6 +14,8 @@ typedef enum BitmapCheckFlags {
BDRV_BITMAP_INCONSISTENT)
#define BDRV_BITMAP_ALLOW_RO (BDRV_BITMAP_BUSY | BDRV_BITMAP_INCONSISTENT)
#define BDRV_BITMAP_MAX_NAME_SIZE 1023
BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
uint32_t granularity,
const char *name,

2
qapi/block-core.json
View File

@ -2042,7 +2042,7 @@
#
# @node: name of device/node which the bitmap is tracking
#
# @name: name of the dirty bitmap
# @name: name of the dirty bitmap (must be less than 1024 bytes)
#
# @granularity: the bitmap granularity, default is 64k for
# block-dirty-bitmap-add