diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/Makefile.objs | 1 | ||||
| -rw-r--r-- | block/qapi.c | 3 | ||||
| -rw-r--r-- | block/write-threshold.c | 125 |
3 files changed, 129 insertions, 0 deletions
diff --git a/block/Makefile.objs b/block/Makefile.objs index 04b0e43eb1..010afad71a 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -20,6 +20,7 @@ block-obj-$(CONFIG_GLUSTERFS) += gluster.o block-obj-$(CONFIG_ARCHIPELAGO) += archipelago.o block-obj-$(CONFIG_LIBSSH2) += ssh.o block-obj-y += accounting.o +block-obj-y += write-threshold.o common-obj-y += stream.o common-obj-y += commit.o diff --git a/block/qapi.c b/block/qapi.c index d1a891796c..1808e67336 100644 --- a/block/qapi.c +++ b/block/qapi.c @@ -24,6 +24,7 @@ #include "block/qapi.h" #include "block/block_int.h" +#include "block/write-threshold.h" #include "qmp-commands.h" #include "qapi-visit.h" #include "qapi/qmp-output-visitor.h" @@ -89,6 +90,8 @@ BlockDeviceInfo *bdrv_block_device_info(BlockDriverState *bs) info->iops_size = cfg.op_size; } + info->write_threshold = bdrv_write_threshold_get(bs); + return info; } diff --git a/block/write-threshold.c b/block/write-threshold.c new file mode 100644 index 0000000000..c2cd517716 --- /dev/null +++ b/block/write-threshold.c @@ -0,0 +1,125 @@ +/* + * QEMU System Emulator block write threshold notification + * + * Copyright Red Hat, Inc. 2014 + * + * Authors: + * Francesco Romani <fromani@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2 or later. + * See the COPYING.LIB file in the top-level directory. + */ + +#include "block/block_int.h" +#include "block/coroutine.h" +#include "block/write-threshold.h" +#include "qemu/notify.h" +#include "qapi-event.h" +#include "qmp-commands.h" + + +uint64_t bdrv_write_threshold_get(const BlockDriverState *bs) +{ + return bs->write_threshold_offset; +} + +bool bdrv_write_threshold_is_set(const BlockDriverState *bs) +{ + return bs->write_threshold_offset > 0; +} + +static void write_threshold_disable(BlockDriverState *bs) +{ + if (bdrv_write_threshold_is_set(bs)) { + notifier_with_return_remove(&bs->write_threshold_notifier); + bs->write_threshold_offset = 0; + } +} + +uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs, + const BdrvTrackedRequest *req) +{ + if (bdrv_write_threshold_is_set(bs)) { + if (req->offset > bs->write_threshold_offset) { + return (req->offset - bs->write_threshold_offset) + req->bytes; + } + if ((req->offset + req->bytes) > bs->write_threshold_offset) { + return (req->offset + req->bytes) - bs->write_threshold_offset; + } + } + return 0; +} + +static int coroutine_fn before_write_notify(NotifierWithReturn *notifier, + void *opaque) +{ + BdrvTrackedRequest *req = opaque; + BlockDriverState *bs = req->bs; + uint64_t amount = 0; + + amount = bdrv_write_threshold_exceeded(bs, req); + if (amount > 0) { + qapi_event_send_block_write_threshold( + bs->node_name, + amount, + bs->write_threshold_offset, + &error_abort); + + /* autodisable to avoid flooding the monitor */ + write_threshold_disable(bs); + } + + return 0; /* should always let other notifiers run */ +} + +static void write_threshold_register_notifier(BlockDriverState *bs) +{ + bs->write_threshold_notifier.notify = before_write_notify; + notifier_with_return_list_add(&bs->before_write_notifiers, + &bs->write_threshold_notifier); +} + +static void write_threshold_update(BlockDriverState *bs, + int64_t threshold_bytes) +{ + bs->write_threshold_offset = threshold_bytes; +} + +void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes) +{ + if (bdrv_write_threshold_is_set(bs)) { + if (threshold_bytes > 0) { + write_threshold_update(bs, threshold_bytes); + } else { + write_threshold_disable(bs); + } + } else { + if (threshold_bytes > 0) { + /* avoid multiple registration */ + write_threshold_register_notifier(bs); + write_threshold_update(bs, threshold_bytes); + } + /* discard bogus disable request */ + } +} + +void qmp_block_set_write_threshold(const char *node_name, + uint64_t threshold_bytes, + Error **errp) +{ + BlockDriverState *bs; + AioContext *aio_context; + + bs = bdrv_find_node(node_name); + if (!bs) { + error_set(errp, QERR_DEVICE_NOT_FOUND, node_name); + return; + } + + aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(aio_context); + + bdrv_write_threshold_set(bs, threshold_bytes); + + aio_context_release(aio_context); +} |