block: vhdx - improve error message, and .bdrv_check implementation

If there is a dirty log file to be replayed in a VHDX image, it is
replayed in .vhdx_open().  However, if the file is opened read-only,
then a somewhat cryptic error message results.

This adds a more helpful error message for the user.  If an image file
contains a log to be replayed, and is opened read-only, the user is
instructed to run 'qemu-img check -r all' on the image file.

Running qemu-img check -r all will cause the image file to be opened
r/w, which will replay the log file.  If a log file replay is detected,
this is flagged, and bdrv_check will increase the corruptions_fixed
count for the image.

[Fixed typo in error message that was pointed out by Eric Blake
<eblake@redhat.com>.
--Stefan]

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/block/vhdx.h b/block/vhdx.h
index 51183b243c..2acd7c2d19 100644
--- a/block/vhdx.h
+++ b/block/vhdx.h
@@ -394,6 +394,8 @@ typedef struct BDRVVHDXState {
 
     Error *migration_blocker;
 
+    bool log_replayed_on_open;
+
     QLIST_HEAD(VHDXRegionHead, VHDXRegionEntry) regions;
 } BDRVVHDXState;
 
@@ -408,7 +410,8 @@ uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
 
 bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset);
 
-int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed);
+int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
+                   Error **errp);
 
 int vhdx_log_write_and_flush(BlockDriverState *bs, BDRVVHDXState *s,
                              void *data, uint32_t length, uint64_t offset);