qemu-img: Fix Column Width and Improve Formatting in snapshot list

When running the command `qemu-img snapshot -l SNAPSHOT` the output of
VM_CLOCK (measures the offset between host and VM clock) cannot to
accommodate values in the order of thousands (4-digit).

This line [1] hints on the problem. Additionally, the column width for
the VM_CLOCK field was reduced from 15 to 13 spaces in commit b39847a5
in line [2], resulting in a shortage of space.

[1]:
https://gitlab.com/qemu-project/qemu/-/blob/master/block/qapi.c?ref_type=heads#L753
[2]:
https://gitlab.com/qemu-project/qemu/-/blob/master/block/qapi.c?ref_type=heads#L763

This patch restores the column width to 15 spaces and makes adjustments
to the affected iotests accordingly. Furthermore, addresses a potential
source
of confusion by removing whitespace in column headers. Example, VM CLOCK
is modified to VM_CLOCK. Additionally a '--' symbol is introduced when
ICOUNT returns no output for clarity.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2062
Fixes: b39847a50553 ("migration: introduce icount field for snapshots")
Signed-off-by: Abhiram Tilak <atp.exp@gmail.com>
Message-ID: <20240123050354.22152-2-atp.exp@gmail.com>
[kwolf: Fixed up qemu-iotests 261 and 286]
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

7 files changed, 50 insertions, 47 deletions

diff --git a/block/qapi.c b/block/qapi.c
index 31183d4933..2b5793f1d9 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -742,15 +742,15 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
     char *sizing = NULL;
 
     if (!sn) {
-        qemu_printf("%-10s%-17s%8s%20s%13s%11s",
-                    "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK", "ICOUNT");
+        qemu_printf("%-7s %-16s %8s %19s %15s %10s",
+                    "ID", "TAG", "VM_SIZE", "DATE", "VM_CLOCK", "ICOUNT");
     } else {
         g_autoptr(GDateTime) date = g_date_time_new_from_unix_local(sn->date_sec);
         g_autofree char *date_buf = g_date_time_format(date, "%Y-%m-%d %H:%M:%S");
 
         secs = sn->vm_clock_nsec / 1000000000;
         snprintf(clock_buf, sizeof(clock_buf),
-                 "%02d:%02d:%02d.%03d",
+                 "%04d:%02d:%02d.%03d",
                  (int)(secs / 3600),
                  (int)((secs / 60) % 60),
                  (int)(secs % 60),
@@ -759,8 +759,10 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
         if (sn->icount != -1ULL) {
             snprintf(icount_buf, sizeof(icount_buf),
                 "%"PRId64, sn->icount);
+        } else {
+            snprintf(icount_buf, sizeof(icount_buf), "--");
         }
-        qemu_printf("%-9s %-16s %8s%20s%13s%11s",
+        qemu_printf("%-7s %-16s %8s %19s %15s %10s",
                     sn->id_str, sn->name,
                     sizing,
                     date_buf,
diff --git a/tests/qemu-iotests/176.out b/tests/qemu-iotests/176.out
index 45e9153ef3..9c73ef2eea 100644
--- a/tests/qemu-iotests/176.out
+++ b/tests/qemu-iotests/176.out
@@ -37,8 +37,8 @@ Offset          Length          File
 0x7ffe0000      0x20000         TEST_DIR/t.IMGFMT.itmd
 0x83400000      0x200           TEST_DIR/t.IMGFMT.itmd
 Snapshot list:
-ID        TAG
-1         snap
+ID      TAG
+1       snap
 
 === Test pass snapshot.1 ===
 
@@ -78,8 +78,8 @@ Offset          Length          File
 0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
 0x83400000      0x200           TEST_DIR/t.IMGFMT
 Snapshot list:
-ID        TAG
-1         snap
+ID      TAG
+1       snap
 
 === Test pass snapshot.2 ===
 
@@ -119,8 +119,8 @@ Offset          Length          File
 0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
 0x83400000      0x200           TEST_DIR/t.IMGFMT
 Snapshot list:
-ID        TAG
-1         snap
+ID      TAG
+1       snap
 
 === Test pass snapshot.3 ===
 
@@ -157,8 +157,8 @@ Offset          Length          File
 0x7fff0000      0x10000         TEST_DIR/t.IMGFMT
 0x83400000      0x200           TEST_DIR/t.IMGFMT
 Snapshot list:
-ID        TAG
-1         snap
+ID      TAG
+1       snap
 
 === Test pass bitmap.0 ===
 
diff --git a/tests/qemu-iotests/261 b/tests/qemu-iotests/261
index b73da565da..22b969d310 100755
--- a/tests/qemu-iotests/261
+++ b/tests/qemu-iotests/261
@@ -393,7 +393,7 @@ _check_test_img -r all
 
 echo
 echo "$((sn_count - 1)) snapshots should remain:"
-echo "  qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
+echo "  qemu-img info reports $(_img_info | grep -c '^ \{30\}') snapshots"
 echo "  Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
 
 echo
@@ -520,7 +520,7 @@ _check_test_img -r all
 
 echo
 echo '65536 snapshots should remain:'
-echo "  qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
+echo "  qemu-img info reports $(_img_info | grep -c '^ \{30\}') snapshots"
 echo "  Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
 
 # success, all done
diff --git a/tests/qemu-iotests/267.out b/tests/qemu-iotests/267.out
index 7176e376e1..f6f5d8715a 100644
--- a/tests/qemu-iotests/267.out
+++ b/tests/qemu-iotests/267.out
@@ -33,8 +33,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -44,8 +44,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -69,8 +69,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -94,8 +94,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -105,8 +105,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -119,8 +119,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -134,8 +134,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
@@ -145,15 +145,15 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
 Internal snapshots on overlay:
 Snapshot list:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
-1         snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+1       snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 Internal snapshots on backing file:
 
 === -blockdev with NBD server on the backing file ===
@@ -166,17 +166,17 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm snap0
 (qemu) info snapshots
 List of snapshots present on all disks:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
---        snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+--      snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 (qemu) loadvm snap0
 (qemu) quit
 
 Internal snapshots on overlay:
 Snapshot list:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
-1         snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+1       snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 Internal snapshots on backing file:
 Snapshot list:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
-1         snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000           
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+1       snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 *** done
diff --git a/tests/qemu-iotests/286 b/tests/qemu-iotests/286
index 120a8375b7..38216c2a0e 100755
--- a/tests/qemu-iotests/286
+++ b/tests/qemu-iotests/286
@@ -69,7 +69,8 @@ $QEMU_IMG snapshot -l "$TEST_IMG" | tail -n 1 | tr -s ' ' \
           -e 's/\./(VM state size unit)/' \
           -e 's/\./(snapshot date)/' \
           -e 's/\./(snapshot time)/' \
-          -e 's/\./(VM clock)/'
+          -e 's/\./(VM clock)/' \
+          -e 's/\./(icount)/'
 
 # success, all done
 echo "*** done"
diff --git a/tests/qemu-iotests/286.out b/tests/qemu-iotests/286.out
index 39ff07e12c..bb04748e08 100644
--- a/tests/qemu-iotests/286.out
+++ b/tests/qemu-iotests/286.out
@@ -4,5 +4,5 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
 (qemu) quit
 Output structure:
-(snapshot ID) (snapshot name) (VM state size value) (VM state size unit) (snapshot date) (snapshot time) (VM clock)
+(snapshot ID) (snapshot name) (VM state size value) (VM state size unit) (snapshot date) (snapshot time) (VM clock) (icount)
 *** done
diff --git a/tests/qemu-iotests/tests/qcow2-internal-snapshots.out b/tests/qemu-iotests/tests/qcow2-internal-snapshots.out
index 438f535e6a..fedb09224e 100644
--- a/tests/qemu-iotests/tests/qcow2-internal-snapshots.out
+++ b/tests/qemu-iotests/tests/qcow2-internal-snapshots.out
@@ -14,8 +14,8 @@ wrote 524288/524288 bytes at offset 0
 (qemu) quit
 
 Snapshot list:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
-1         snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+1       snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 No errors were found on the image.
 
 === Verify that loading the snapshot reverts to the old content ===
@@ -47,9 +47,9 @@ read 64512/64512 bytes at offset 66560
 (qemu) quit
 
 Snapshot list:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
-1         snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
-2         snap1                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+1       snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
+2       snap1                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 No errors were found on the image.
 
 === qemu-img snapshot can revert to snapshots ===
@@ -79,8 +79,8 @@ read 64512/64512 bytes at offset 66560
 (qemu) quit
 
 Snapshot list:
-ID        TAG               VM SIZE                DATE     VM CLOCK     ICOUNT
-1         snap0                SIZE yyyy-mm-dd hh:mm:ss 00:00:00.000
+ID      TAG               VM_SIZE                DATE        VM_CLOCK     ICOUNT
+1       snap0                SIZE yyyy-mm-dd hh:mm:ss  0000:00:00.000         --
 No errors were found on the image.
 
 === Error cases ===