bdrv_set_aio_context can take care of children recursively, so it is okay to pass down the perm.
Signed-off-by: Fam Zheng <f...@redhat.com> --- block.c | 10 ++++++---- block/vvfat.c | 2 +- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/block.c b/block.c index d98662f..1e5eae7 100644 --- a/block.c +++ b/block.c @@ -1772,7 +1772,8 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, #define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \ | BLK_PERM_WRITE \ | BLK_PERM_WRITE_UNCHANGED \ - | BLK_PERM_RESIZE) + | BLK_PERM_RESIZE \ + | BLK_PERM_AIO_CONTEXT_CHANGE) #define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH) void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, @@ -1815,9 +1816,10 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, perm |= BLK_PERM_CONSISTENT_READ; shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } else { - /* We want consistent read from backing files if the parent needs it. + /* We want consistent read and aio context change from backing files if + * the parent needs it. * No other operations are performed on backing files. */ - perm &= BLK_PERM_CONSISTENT_READ; + perm &= BLK_PERM_CONSISTENT_READ | BLK_PERM_AIO_CONTEXT_CHANGE; /* If the parent can deal with changing data, we're okay with a * writable and resizable backing file. */ @@ -1829,7 +1831,7 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, } shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | - BLK_PERM_WRITE_UNCHANGED; + BLK_PERM_WRITE_UNCHANGED | BLK_PERM_AIO_CONTEXT_CHANGE; } if (bs->open_flags & BDRV_O_INACTIVE) { diff --git a/block/vvfat.c b/block/vvfat.c index 426ca70..599a370 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -3091,7 +3091,7 @@ static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c, if (c == s->qcow) { /* This is a private node, nobody should try to attach to it */ *nperm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE; - *nshared = BLK_PERM_WRITE_UNCHANGED; + *nshared = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_AIO_CONTEXT_CHANGE; } else { /* The backing file is there so 'commit' can use it. vvfat doesn't * access it in any way. */ -- 2.9.4