On Fri, 09/15 12:10, Kevin Wolf wrote: > bdrv_reopen() can switch nodes between read-only and read-write modes. > This has implications for the required permissions on their child nodes. > For example, a qcow2 node requests write permissions on bs->file only if > it is writable itself. > > This means that during bdrv_reopen(), the permissions need to be > recalculated in order to prevent failures where the bs->file > permissions don't match its actual read-only state (e.g. bs->file is a > read-write node, but the permission still enforces read-only access).
Passing reopen_queue around makes the interface and implementations complicated. I wonder if any of the alternatives make sense: 1) Don't pass reopen_queue as a parameter, just pass the one interesting BDRVReopenState pointer. So that callees don't need to call bdrv_reopen_get_flags(). 2) Don't change the prototypes at all, just change .bdrv_reopen_prepare contract so that after it returns, .bdrv_child_perm/.bdrv_check_perm should comply to the new state that would be commited once .bdrv_reopen_commit() is called, or reverted if .bdrv_reopen_abort(). 3) Don't change the prototypes at all, track the reopen progress in block.c generically, (e.g. ignore conflicts and voilations) and update the permissions only after bdrv_reopen_commit(). Fam > > Kevin Wolf (6): > qemu-io: Reset qemuio_blk permissions before each command > block: Add reopen_queue to bdrv_child_perm() > block: Add reopen queue to bdrv_check_perm() > block: Base permissions on rw state after reopen > block: reopen: Queue children after their parents > block: Fix permissions after bdrv_reopen() > > include/block/block.h | 2 +- > include/block/block_int.h | 7 ++ > block.c | 191 > +++++++++++++++++++++++++++++++++------------ > block/commit.c | 1 + > block/mirror.c | 1 + > block/replication.c | 1 + > block/vvfat.c | 1 + > qemu-io.c | 13 +++ > tests/qemu-iotests/187.out | 2 +- > 9 files changed, 169 insertions(+), 50 deletions(-) > > -- > 2.13.5 >
