[Qemu-devel] [PATCH v2 4/4] parallels: 2TB+ parallels images support

["Denis V. Lunev" <den@openvz.org>]

Parallels has released in the recent updates of Parallels Server 5/6
new addition to his image format. Images with signature WithouFreSpacExt
have offsets in the catalog coded not as offsets in sectors (multiple
of 512 bytes) but offsets coded in blocks (i.e. header->tracks * 512)

In this case all 64 bits of header->nb_sectors are used for image size.

This patch implements support of this for qemu-img and also adds specific
check for an incorrect image. Images with block size greater than
INT_MAX/513 are not supported. The biggest available Parallels image
cluster size in the field is 1 Mb. Thus this limit will not hurt
anyone.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Jeff Cody <jcody@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/parallels.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index 466705e..4414a9d 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -30,6 +30,7 @@
 /**************************************************************/
 
 #define HEADER_MAGIC "WithoutFreeSpace"
+#define HEADER_MAGIC2 "WithouFreSpacExt"
 #define HEADER_VERSION 2
 #define HEADER_SIZE 64
 
@@ -54,6 +55,8 @@ typedef struct BDRVParallelsState {
     unsigned int catalog_size;
 
     unsigned int tracks;
+
+    unsigned int off_multiplier;
 } BDRVParallelsState;
 
 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
@@ -63,7 +66,8 @@ static int parallels_probe(const uint8_t *buf, int buf_size, const char *filenam
     if (buf_size < HEADER_SIZE)
         return 0;
 
-    if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&
+    if ((!memcmp(ph->magic, HEADER_MAGIC, 16) ||
+        !memcmp(ph->magic, HEADER_MAGIC2, 16)) &&
         (le32_to_cpu(ph->version) == HEADER_VERSION))
         return 100;
 
@@ -85,21 +89,31 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
         goto fail;
     }
 
+    bs->total_sectors = le64_to_cpu(ph.nb_sectors);
+
     if (le32_to_cpu(ph.version) != HEADER_VERSION) {
         goto fail_format;
     }
-    if (memcmp(ph.magic, HEADER_MAGIC, 16)) {
+    if (!memcmp(ph.magic, HEADER_MAGIC, 16)) {
+        s->off_multiplier = 1;
+        bs->total_sectors = 0xffffffff & bs->total_sectors;
+    } else if (!memcmp(ph.magic, HEADER_MAGIC2, 16)) {
+        s->off_multiplier = le32_to_cpu(ph.tracks);
+    } else {
         goto fail_format;
     }
 
-    bs->total_sectors = 0xffffffff & le64_to_cpu(ph.nb_sectors);
-
     s->tracks = le32_to_cpu(ph.tracks);
     if (s->tracks == 0) {
         error_setg(errp, "Invalid image: Zero sectors per track");
         ret = -EINVAL;
         goto fail;
     }
+    if (s->tracks > INT32_MAX/513) {
+        error_setg(errp, "Invalid image: Too big cluster");
+        ret = -EFBIG;
+        goto fail;
+    }
 
     s->catalog_size = le32_to_cpu(ph.catalog_entries);
     if (s->catalog_size > INT_MAX / 4) {
@@ -139,7 +153,8 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
     /* not allocated */
     if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
         return -1;
-    return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;
+    return
+        ((uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset) * 512;
 }
 
 static int parallels_read(BlockDriverState *bs, int64_t sector_num,
-- 
1.9.1