The assertion is currently failing. We can't require callers to have
write permissions when all they are doing is a read, so comment it out.
Add a FIXME comment in the code so that the check is re-enabled when
copy on read is refactored into its own filter driver.
Reported-by: Richard W.M. Jones <rjo...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Richard W.M. Jones <rjo...@redhat.com>
---
block/io.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index 2709a70..7321dda 100644
--- a/block/io.c
+++ b/block/io.c
@@ -945,7 +945,14 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild
*child,
size_t skip_bytes;
int ret;
- assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
+ /* FIXME We cannot require callers to have write permissions when all they
+ * are doing is a read request. If we did things right, write permissions
+ * would be obtained anyway, but internally by the copy-on-read code. As
+ * long as it is implemented here rather than in a separat filter driver,
+ * the copy-on-read code doesn't have its own BdrvChild, however, for which
+ * it could request permissions. Therefore we have to bypass the permission
+ * system for the moment. */
+ // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
/* Cover entire cluster so no additional backing file I/O is required when
* allocating cluster in the image file.
--
1.8.3.1
