qemu-img: Saner printing of large file sizes

Disk sizes close to INT64_MAX cause overflow, for some pretty
ridiculous output:

  $ ./nbdkit -U - memory size=$((2**63 - 512)) --run 'qemu-img info $nbd'
  image: nbd+unix://?socket=/tmp/nbdkitHSAzNz/socket
  file format: raw
  virtual size: -8388607T (9223372036854775296 bytes)
  disk size: unavailable

But there's no reason to have two separate implementations of integer
to human-readable abbreviation, where one has overflow and stops at
'T', while the other avoids overflow and goes all the way to 'E'. With
this patch, the output now claims 8EiB instead of -8388607T, which
really is the correct rounding of largest file size supported by qemu
(we could go 511 bytes larger if we used byte-accurate sizing instead
of rounding up to the next sector boundary, but that wouldn't change
the human-readable result).

Quite a few iotests need updates to expected output to match.

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Max Reitz <mreitz@redhat.com>

1 files changed, 11 insertions, 38 deletions

diff --git a/block/qapi.c b/block/qapi.c
index e3e74f8..0c13c86 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -631,42 +631,13 @@ BlockStatsList *qmp_query_blockstats(bool has_query_nodes,
     return head;
 }
 
-#define NB_SUFFIXES 4
-
-static char *get_human_readable_size(char *buf, int buf_size, int64_t size)
-{
-    static const char suffixes[NB_SUFFIXES] = {'K', 'M', 'G', 'T'};
-    int64_t base;
-    int i;
-
-    if (size <= 999) {
-        snprintf(buf, buf_size, "%" PRId64, size);
-    } else {
-        base = 1024;
-        for (i = 0; i < NB_SUFFIXES; i++) {
-            if (size < (10 * base)) {
-                snprintf(buf, buf_size, "%0.1f%c",
-                         (double)size / base,
-                         suffixes[i]);
-                break;
-            } else if (size < (1000 * base) || i == (NB_SUFFIXES - 1)) {
-                snprintf(buf, buf_size, "%" PRId64 "%c",
-                         ((size + (base >> 1)) / base),
-                         suffixes[i]);
-                break;
-            }
-            base = base * 1024;
-        }
-    }
-    return buf;
-}
-
 void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
 {
-    char buf1[128], date_buf[128], clock_buf[128];
+    char date_buf[128], clock_buf[128];
     struct tm tm;
     time_t ti;
     int64_t secs;
+    char *sizing = NULL;
 
     if (!sn) {
         qemu_printf("%-10s%-20s%7s%20s%15s",
@@ -683,13 +654,14 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
                  (int)((secs / 60) % 60),
                  (int)(secs % 60),
                  (int)((sn->vm_clock_nsec / 1000000) % 1000));
+        sizing = size_to_str(sn->vm_state_size);
         qemu_printf("%-10s%-20s%7s%20s%15s",
                     sn->id_str, sn->name,
-                    get_human_readable_size(buf1, sizeof(buf1),
-                                            sn->vm_state_size),
+                    sizing,
                     date_buf,
                     clock_buf);
     }
+    g_free(sizing);
 }
 
 static void dump_qdict(int indentation, QDict *dict);
@@ -787,14 +759,13 @@ void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec)
 
 void bdrv_image_info_dump(ImageInfo *info)
 {
-    char size_buf[128], dsize_buf[128];
+    char *size_buf, *dsize_buf;
     if (!info->has_actual_size) {
-        snprintf(dsize_buf, sizeof(dsize_buf), "unavailable");
+        dsize_buf = g_strdup("unavailable");
     } else {
-        get_human_readable_size(dsize_buf, sizeof(dsize_buf),
-                                info->actual_size);
+        dsize_buf = size_to_str(info->actual_size);
     }
-    get_human_readable_size(size_buf, sizeof(size_buf), info->virtual_size);
+    size_buf = size_to_str(info->virtual_size);
     qemu_printf("image: %s\n"
                 "file format: %s\n"
                 "virtual size: %s (%" PRId64 " bytes)\n"
@@ -802,6 +773,8 @@ void bdrv_image_info_dump(ImageInfo *info)
                 info->filename, info->format, size_buf,
                 info->virtual_size,
                 dsize_buf);
+    g_free(size_buf);
+    g_free(dsize_buf);
 
     if (info->has_encrypted && info->encrypted) {
         qemu_printf("encrypted: yes\n");