This series adds "read-only" to the options QDict, fixing a long-standing problem with the reopening code.
[E] <- [D] <- [C] <- [B] <- [A] In a normal scenario, the active layer [A] is in read-write mode and everything else is read-only. If we reopen [D] in read-write mode and later reopen [B], then [D] will become read-only when inheriting the flags from its parent (see bdrv_backing_options()). With this series, inheriting options doesn't need to override values that have been explicitly set before. The BDRV_O_RDWR flag is not removed yet, but its keep in sync with the value of the "read-only" option. Removing the BDRV_O_RDWR flag is not straightforward in all cases and can result in code that is significantly slower and less readable. Therefore it will be dealt with in the future. Regards, Berto Alberto Garcia (7): block: Remove bdrv_is_snapshot block: Set BDRV_O_ALLOW_RDWR and snapshot_options before storing the flags block: Update bs->open_flags earlier in bdrv_open_common() block: Add "read-only" to the options QDict block: Don't queue the same BDS twice in bdrv_reopen_queue_child() commit: Add 'base' to the reopen queue before 'overlay_bs' block: rename "read-only" to BDRV_OPT_READ_ONLY block.c | 86 +++++++++++++++++++++++++++++++++++++-------------- block/commit.c | 8 ++--- block/vvfat.c | 3 +- blockdev.c | 28 ++++++++++------- include/block/block.h | 2 +- 5 files changed, 86 insertions(+), 41 deletions(-) -- 2.9.3