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authorKevin Wolf <kwolf@redhat.com>2017-04-07 12:29:05 +0200
committerKevin Wolf <kwolf@redhat.com>2017-04-07 14:44:06 +0200
commit1bf03e66fd03af46ff0f98dd04b6e28f432ac1e3 (patch)
treeecf68ddad2419e4259586f79b8a28c2b3a341c69
parent89aa0465b9135d70682420918b28b6e38a0f6322 (diff)
block: Don't check permissions for copy on read
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 <rjones@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
-rw-r--r--block/io.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/block/io.c b/block/io.c
index 2709a7007f..7321ddab3d 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.