[Qemu-devel] [PULL 36/41] vhdx: Fix "log that needs to be replayed" error message

[Markus Armbruster]

The arguments of error_setg_errno() should yield a short error string
without newlines.

Here, we try to append additional help to the error message by
embedding newlines in the error string.  That's nice, but it's doesn't
play nicely with the errno part.  tests/qemu-iotests/070.out shows the
resulting mess:

    can't open device TEST_DIR/iotest-dirtylog-10G-4M.vhdx: VHDX image file 
'TEST_DIR/iotest-dirtylog-10G-4M.vhdx' opened read-only, but contains a log 
that needs to be replayed.  To replay the log, execute:
     qemu-img check -r all 'TEST_DIR/iotest-dirtylog-10G-4M.vhdx': Operation 
not permitted

Switch to error_setg() and error_append_hint().  Result:

    can't open device TEST_DIR/iotest-dirtylog-10G-4M.vhdx: VHDX image file 
'TEST_DIR/iotest-dirtylog-10G-4M.vhdx' opened read-only, but contains a log 
that needs to be replayed
    To replay the log, run:
    qemu-img check -r all 'TEST_DIR/iotest-dirtylog-10G-4M.vhdx'

Signed-off-by: Markus Armbruster <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
---
 block/vhdx-log.c           | 13 +++++++------
 tests/qemu-iotests/070.out |  5 +++--
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/block/vhdx-log.c b/block/vhdx-log.c
index 47ae4b1..ab86416 100644
--- a/block/vhdx-log.c
+++ b/block/vhdx-log.c
@@ -784,12 +784,13 @@ int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState 
*s, bool *flushed,
     if (logs.valid) {
         if (bs->read_only) {
             ret = -EPERM;
-            error_setg_errno(errp, EPERM,
-                             "VHDX image file '%s' opened read-only, but "
-                             "contains a log that needs to be replayed.  To "
-                             "replay the log, execute:\n qemu-img check -r "
-                             "all '%s'",
-                             bs->filename, bs->filename);
+            error_setg(errp,
+                       "VHDX image file '%s' opened read-only, but "
+                       "contains a log that needs to be replayed",
+                       bs->filename);
+            error_append_hint(errp,  "To replay the log, run:\n"
+                              "qemu-img check -r all '%s'\n",
+                              bs->filename);
             goto exit;
         }
         /* now flush the log */
diff --git a/tests/qemu-iotests/070.out b/tests/qemu-iotests/070.out
index ffd4251..131a5b1 100644
--- a/tests/qemu-iotests/070.out
+++ b/tests/qemu-iotests/070.out
@@ -1,8 +1,9 @@
 QA output created by 070
 
 === Verify open image read-only fails, due to dirty log ===
-can't open device TEST_DIR/iotest-dirtylog-10G-4M.vhdx: VHDX image file 
'TEST_DIR/iotest-dirtylog-10G-4M.vhdx' opened read-only, but contains a log 
that needs to be replayed.  To replay the log, execute:
- qemu-img check -r all 'TEST_DIR/iotest-dirtylog-10G-4M.vhdx': Operation not 
permitted
+can't open device TEST_DIR/iotest-dirtylog-10G-4M.vhdx: VHDX image file 
'TEST_DIR/iotest-dirtylog-10G-4M.vhdx' opened read-only, but contains a log 
that needs to be replayed
+To replay the log, run:
+qemu-img check -r all 'TEST_DIR/iotest-dirtylog-10G-4M.vhdx'
  no file open, try 'help open'
 === Verify open image replays log  ===
 read 18874368/18874368 bytes at offset 0
-- 
2.4.3