| Message ID | 1475237406-26917-4-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
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 <famz@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;
On Fri, 10/21 23:04, Max Reitz wrote: > > +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. The idea was to assert no two bits are set at the same time. But I seem to have forgotten to actually add the assertion. > > > + > > +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... I can't think of a reason for any caller to do something different for -ENOTSUP from success, hence the check here. > > > + } 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 |? Yes. Thanks for catching it. > > > + } > > + > > 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...? :-) Yes, sounds good. Fam
On 25.10.2016 07:48, Fam Zheng wrote: > On Fri, 10/21 23:04, Max Reitz wrote: [...] >>> +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... > > I can't think of a reason for any caller to do something different for -ENOTSUP > from success, hence the check here. OK, that's fine, then. Max
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; 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; + } +} + +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; + } 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; + } + 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) 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); bs->open_flags |= BDRV_O_INACTIVE; } return 0; diff --git a/include/block/block.h b/include/block/block.h index cecab7a..828ab14 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -272,7 +272,8 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, BlockDriverState *bdrv_find_overlay(BlockDriverState *active, BlockDriverState *bs); BlockDriverState *bdrv_find_base(BlockDriverState *bs); - +ImageLockMode bdrv_lock_mode_from_flags(int flags); +ImageLockMode bdrv_get_lock_mode(BlockDriverState *bs); typedef struct BdrvCheckResult { int corruptions; @@ -529,5 +530,6 @@ void bdrv_drained_end(BlockDriverState *bs); void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child, Error **errp); void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp); +int bdrv_set_lock_mode(BlockDriverState *bs, ImageLockMode mode); #endif diff --git a/include/block/block_int.h b/include/block/block_int.h index 3e79228..486e1ea 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -319,6 +319,10 @@ struct BlockDriver { Error **errp); void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child, Error **errp); + /** + * Lock/unlock the image. + */ + int (*bdrv_lockf)(BlockDriverState *bs, ImageLockMode mode); QLIST_ENTRY(BlockDriver) list; }; @@ -528,6 +532,7 @@ struct BlockDriverState { unsigned io_plug_disabled; int quiesce_counter; + ImageLockMode cur_lock; }; struct BlockBackendRootState { diff --git a/include/hw/block/block.h b/include/hw/block/block.h index df9d207..8c04469 100644 --- a/include/hw/block/block.h +++ b/include/hw/block/block.h @@ -12,11 +12,13 @@ #define HW_BLOCK_H #include "qemu-common.h" +#include "block/block.h" /* Configuration */ typedef struct BlockConf { BlockBackend *blk; + ImageLockMode lock_mode; uint16_t physical_block_size; uint16_t logical_block_size; uint16_t min_io_size;
Block drivers can implement this new operation .bdrv_lockf to actually lock the image in the protocol specific way. Signed-off-by: Fam Zheng <famz@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(-)