On 30.09.2016 14:09, Fam Zheng wrote: > Block drivers can implement this new operation .bdrv_lockf to actually lock > the > image in the protocol specific way. > > Signed-off-by: Fam Zheng <f...@redhat.com> > --- > block.c | 52 > +++++++++++++++++++++++++++++++++++++++++++++++ > include/block/block.h | 4 +++- > include/block/block_int.h | 5 +++++ > include/hw/block/block.h | 2 ++ > 4 files changed, 62 insertions(+), 1 deletion(-) > > diff --git a/block.c b/block.c > index 493ecf3..9d600df 100644 > --- a/block.c > +++ b/block.c > @@ -235,6 +235,7 @@ BlockDriverState *bdrv_new(void) > notifier_with_return_list_init(&bs->before_write_notifiers); > bs->refcnt = 1; > bs->aio_context = qemu_get_aio_context(); > + bs->cur_lock = IMAGE_LOCK_MODE__MAX;
(Yes, I know, I'm supposed to write a high-level review, but...) I don't really like using values for enums that are not actually supposed to be part of the enum. Maybe nolock would be a reasonable choice? > qemu_co_queue_init(&bs->flush_queue); > > @@ -925,6 +926,48 @@ out: > g_free(gen_node_name); > } > > +ImageLockMode bdrv_lock_mode_from_flags(int flags) > +{ > + if (flags & BDRV_O_NO_LOCK) { > + return IMAGE_LOCK_MODE_NOLOCK; > + } else if (flags & BDRV_O_SHARED_LOCK) { > + return IMAGE_LOCK_MODE_SHARED; > + } else if (flags & BDRV_O_EXCLUSIVE_LOCK) { > + return IMAGE_LOCK_MODE_EXCLUSIVE; > + } else { > + return IMAGE_LOCK_MODE_AUTO; > + } > +} I don't know if there's been any discussion about the order of the flags here, but I personally would order them exactly the other way around: Asking for exclusive locking should override nolock, in my opinion. > + > +ImageLockMode bdrv_get_lock_mode(BlockDriverState *bs) > +{ > + return bs->cur_lock; > +} > + > +int bdrv_set_lock_mode(BlockDriverState *bs, ImageLockMode mode) > +{ > + int ret; > + > + if (bs->cur_lock == mode) { > + return 0; > + } else if (!bs->drv) { > + return -ENOMEDIUM; > + } else if (!bs->drv->bdrv_lockf) { > + if (bs->file) { > + return bdrv_set_lock_mode(bs->file->bs, mode); > + } > + return 0; > + } > + ret = bs->drv->bdrv_lockf(bs, mode); > + if (ret == -ENOTSUP) { > + /* Handle it the same way as !bs->drv->bdrv_lockf */ > + ret = 0; Yes, well, why do you handle both as success? Wouldn't returning -ENOTSUP make more sense? I guess the caller can find out itself by checking whether bs->cur_lock has changed, but... > + } else if (ret == 0) { > + bs->cur_lock = mode; > + } > + return ret; > +} > + > static QemuOptsList bdrv_runtime_opts = { > .name = "bdrv_common", > .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head), > @@ -1076,6 +1119,10 @@ static int bdrv_open_common(BlockDriverState *bs, > BdrvChild *file, > goto free_and_fail; > } > > + if (open_flags & BDRV_O_INACTIVE) { > + open_flags = (open_flags & ~BDRV_O_LOCK_MASK) & BDRV_O_NO_LOCK; I suppose the second & is supposed to be a |? > + } > + > ret = refresh_total_sectors(bs, bs->total_sectors); > if (ret < 0) { > error_setg_errno(errp, -ret, "Could not refresh total sector count"); > @@ -2273,6 +2320,7 @@ static void bdrv_close(BlockDriverState *bs) > if (bs->drv) { > BdrvChild *child, *next; > > + bdrv_set_lock_mode(bs, IMAGE_LOCK_MODE_NOLOCK); > bs->drv->bdrv_close(bs); > bs->drv = NULL; > > @@ -3188,6 +3236,9 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error > **errp) This function's name is pretty weird... Maybe it would be better to rename it to "bdrv_complete_incoming" or something. (Unrelated to this series, of course.) > error_setg_errno(errp, -ret, "Could not refresh total sector count"); > return; > } > + if (bs->cur_lock != IMAGE_LOCK_MODE__MAX) { > + bdrv_set_lock_mode(bs, bs->cur_lock); > + } > } > > void bdrv_invalidate_cache_all(Error **errp) > @@ -3230,6 +3281,7 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs, > } > > if (setting_flag) { > + ret = bdrv_set_lock_mode(bs, IMAGE_LOCK_MODE_NOLOCK); Maybe it would make sense to do something with the return value...? :-) At least you should probably check whether bdrv_get_lock_mode(bs) == IMAGE_LOCK_MODE_NOLOCK. Max > bs->open_flags |= BDRV_O_INACTIVE; > } > return 0;
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