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Diffstat (limited to 'block/block-backend.c')
| -rw-r--r-- | block/block-backend.c | 2454 |
1 files changed, 2454 insertions, 0 deletions
diff --git a/block/block-backend.c b/block/block-backend.c new file mode 100644 index 000000000..12ef80ea1 --- /dev/null +++ b/block/block-backend.c @@ -0,0 +1,2454 @@ +/* + * QEMU Block backends + * + * Copyright (C) 2014-2016 Red Hat, Inc. + * + * Authors: + * Markus Armbruster <armbru@redhat.com>, + * + * This work is licensed under the terms of the GNU LGPL, version 2.1 + * or later. See the COPYING.LIB file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "sysemu/block-backend.h" +#include "block/block_int.h" +#include "block/blockjob.h" +#include "block/coroutines.h" +#include "block/throttle-groups.h" +#include "hw/qdev-core.h" +#include "sysemu/blockdev.h" +#include "sysemu/runstate.h" +#include "sysemu/replay.h" +#include "qapi/error.h" +#include "qapi/qapi-events-block.h" +#include "qemu/id.h" +#include "qemu/main-loop.h" +#include "qemu/option.h" +#include "trace.h" +#include "migration/misc.h" + +/* Number of coroutines to reserve per attached device model */ +#define COROUTINE_POOL_RESERVATION 64 + +#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ + +static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb); + +typedef struct BlockBackendAioNotifier { + void (*attached_aio_context)(AioContext *new_context, void *opaque); + void (*detach_aio_context)(void *opaque); + void *opaque; + QLIST_ENTRY(BlockBackendAioNotifier) list; +} BlockBackendAioNotifier; + +struct BlockBackend { + char *name; + int refcnt; + BdrvChild *root; + AioContext *ctx; + DriveInfo *legacy_dinfo; /* null unless created by drive_new() */ + QTAILQ_ENTRY(BlockBackend) link; /* for block_backends */ + QTAILQ_ENTRY(BlockBackend) monitor_link; /* for monitor_block_backends */ + BlockBackendPublic public; + + DeviceState *dev; /* attached device model, if any */ + const BlockDevOps *dev_ops; + void *dev_opaque; + + /* the block size for which the guest device expects atomicity */ + int guest_block_size; + + /* If the BDS tree is removed, some of its options are stored here (which + * can be used to restore those options in the new BDS on insert) */ + BlockBackendRootState root_state; + + bool enable_write_cache; + + /* I/O stats (display with "info blockstats"). */ + BlockAcctStats stats; + + BlockdevOnError on_read_error, on_write_error; + bool iostatus_enabled; + BlockDeviceIoStatus iostatus; + + uint64_t perm; + uint64_t shared_perm; + bool disable_perm; + + bool allow_aio_context_change; + bool allow_write_beyond_eof; + + NotifierList remove_bs_notifiers, insert_bs_notifiers; + QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers; + + int quiesce_counter; + CoQueue queued_requests; + bool disable_request_queuing; + + VMChangeStateEntry *vmsh; + bool force_allow_inactivate; + + /* Number of in-flight aio requests. BlockDriverState also counts + * in-flight requests but aio requests can exist even when blk->root is + * NULL, so we cannot rely on its counter for that case. + * Accessed with atomic ops. + */ + unsigned int in_flight; +}; + +typedef struct BlockBackendAIOCB { + BlockAIOCB common; + BlockBackend *blk; + int ret; +} BlockBackendAIOCB; + +static const AIOCBInfo block_backend_aiocb_info = { + .get_aio_context = blk_aiocb_get_aio_context, + .aiocb_size = sizeof(BlockBackendAIOCB), +}; + +static void drive_info_del(DriveInfo *dinfo); +static BlockBackend *bdrv_first_blk(BlockDriverState *bs); + +/* All BlockBackends */ +static QTAILQ_HEAD(, BlockBackend) block_backends = + QTAILQ_HEAD_INITIALIZER(block_backends); + +/* All BlockBackends referenced by the monitor and which are iterated through by + * blk_next() */ +static QTAILQ_HEAD(, BlockBackend) monitor_block_backends = + QTAILQ_HEAD_INITIALIZER(monitor_block_backends); + +static void blk_root_inherit_options(BdrvChildRole role, bool parent_is_format, + int *child_flags, QDict *child_options, + int parent_flags, QDict *parent_options) +{ + /* We're not supposed to call this function for root nodes */ + abort(); +} +static void blk_root_drained_begin(BdrvChild *child); +static bool blk_root_drained_poll(BdrvChild *child); +static void blk_root_drained_end(BdrvChild *child, int *drained_end_counter); + +static void blk_root_change_media(BdrvChild *child, bool load); +static void blk_root_resize(BdrvChild *child); + +static bool blk_root_can_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore, Error **errp); +static void blk_root_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore); + +static char *blk_root_get_parent_desc(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + g_autofree char *dev_id = NULL; + + if (blk->name) { + return g_strdup_printf("block device '%s'", blk->name); + } + + dev_id = blk_get_attached_dev_id(blk); + if (*dev_id) { + return g_strdup_printf("block device '%s'", dev_id); + } else { + /* TODO Callback into the BB owner for something more detailed */ + return g_strdup("an unnamed block device"); + } +} + +static const char *blk_root_get_name(BdrvChild *child) +{ + return blk_name(child->opaque); +} + +static void blk_vm_state_changed(void *opaque, bool running, RunState state) +{ + Error *local_err = NULL; + BlockBackend *blk = opaque; + + if (state == RUN_STATE_INMIGRATE) { + return; + } + + qemu_del_vm_change_state_handler(blk->vmsh); + blk->vmsh = NULL; + blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err); + if (local_err) { + error_report_err(local_err); + } +} + +/* + * Notifies the user of the BlockBackend that migration has completed. qdev + * devices can tighten their permissions in response (specifically revoke + * shared write permissions that we needed for storage migration). + * + * If an error is returned, the VM cannot be allowed to be resumed. + */ +static void blk_root_activate(BdrvChild *child, Error **errp) +{ + BlockBackend *blk = child->opaque; + Error *local_err = NULL; + + if (!blk->disable_perm) { + return; + } + + blk->disable_perm = false; + + blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err); + if (local_err) { + error_propagate(errp, local_err); + blk->disable_perm = true; + return; + } + + if (runstate_check(RUN_STATE_INMIGRATE)) { + /* Activation can happen when migration process is still active, for + * example when nbd_server_add is called during non-shared storage + * migration. Defer the shared_perm update to migration completion. */ + if (!blk->vmsh) { + blk->vmsh = qemu_add_vm_change_state_handler(blk_vm_state_changed, + blk); + } + return; + } + + blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err); + if (local_err) { + error_propagate(errp, local_err); + blk->disable_perm = true; + return; + } +} + +void blk_set_force_allow_inactivate(BlockBackend *blk) +{ + blk->force_allow_inactivate = true; +} + +static bool blk_can_inactivate(BlockBackend *blk) +{ + /* If it is a guest device, inactivate is ok. */ + if (blk->dev || blk_name(blk)[0]) { + return true; + } + + /* Inactivating means no more writes to the image can be done, + * even if those writes would be changes invisible to the + * guest. For block job BBs that satisfy this, we can just allow + * it. This is the case for mirror job source, which is required + * by libvirt non-shared block migration. */ + if (!(blk->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED))) { + return true; + } + + return blk->force_allow_inactivate; +} + +static int blk_root_inactivate(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + + if (blk->disable_perm) { + return 0; + } + + if (!blk_can_inactivate(blk)) { + return -EPERM; + } + + blk->disable_perm = true; + if (blk->root) { + bdrv_child_try_set_perm(blk->root, 0, BLK_PERM_ALL, &error_abort); + } + + return 0; +} + +static void blk_root_attach(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + BlockBackendAioNotifier *notifier; + + trace_blk_root_attach(child, blk, child->bs); + + QLIST_FOREACH(notifier, &blk->aio_notifiers, list) { + bdrv_add_aio_context_notifier(child->bs, + notifier->attached_aio_context, + notifier->detach_aio_context, + notifier->opaque); + } +} + +static void blk_root_detach(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + BlockBackendAioNotifier *notifier; + + trace_blk_root_detach(child, blk, child->bs); + + QLIST_FOREACH(notifier, &blk->aio_notifiers, list) { + bdrv_remove_aio_context_notifier(child->bs, + notifier->attached_aio_context, + notifier->detach_aio_context, + notifier->opaque); + } +} + +static AioContext *blk_root_get_parent_aio_context(BdrvChild *c) +{ + BlockBackend *blk = c->opaque; + + return blk_get_aio_context(blk); +} + +static const BdrvChildClass child_root = { + .inherit_options = blk_root_inherit_options, + + .change_media = blk_root_change_media, + .resize = blk_root_resize, + .get_name = blk_root_get_name, + .get_parent_desc = blk_root_get_parent_desc, + + .drained_begin = blk_root_drained_begin, + .drained_poll = blk_root_drained_poll, + .drained_end = blk_root_drained_end, + + .activate = blk_root_activate, + .inactivate = blk_root_inactivate, + + .attach = blk_root_attach, + .detach = blk_root_detach, + + .can_set_aio_ctx = blk_root_can_set_aio_ctx, + .set_aio_ctx = blk_root_set_aio_ctx, + + .get_parent_aio_context = blk_root_get_parent_aio_context, +}; + +/* + * Create a new BlockBackend with a reference count of one. + * + * @perm is a bitmasks of BLK_PERM_* constants which describes the permissions + * to request for a block driver node that is attached to this BlockBackend. + * @shared_perm is a bitmask which describes which permissions may be granted + * to other users of the attached node. + * Both sets of permissions can be changed later using blk_set_perm(). + * + * Return the new BlockBackend on success, null on failure. + */ +BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm) +{ + BlockBackend *blk; + + blk = g_new0(BlockBackend, 1); + blk->refcnt = 1; + blk->ctx = ctx; + blk->perm = perm; + blk->shared_perm = shared_perm; + blk_set_enable_write_cache(blk, true); + + blk->on_read_error = BLOCKDEV_ON_ERROR_REPORT; + blk->on_write_error = BLOCKDEV_ON_ERROR_ENOSPC; + + block_acct_init(&blk->stats); + + qemu_co_queue_init(&blk->queued_requests); + notifier_list_init(&blk->remove_bs_notifiers); + notifier_list_init(&blk->insert_bs_notifiers); + QLIST_INIT(&blk->aio_notifiers); + + QTAILQ_INSERT_TAIL(&block_backends, blk, link); + return blk; +} + +/* + * Create a new BlockBackend connected to an existing BlockDriverState. + * + * @perm is a bitmasks of BLK_PERM_* constants which describes the + * permissions to request for @bs that is attached to this + * BlockBackend. @shared_perm is a bitmask which describes which + * permissions may be granted to other users of the attached node. + * Both sets of permissions can be changed later using blk_set_perm(). + * + * Return the new BlockBackend on success, null on failure. + */ +BlockBackend *blk_new_with_bs(BlockDriverState *bs, uint64_t perm, + uint64_t shared_perm, Error **errp) +{ + BlockBackend *blk = blk_new(bdrv_get_aio_context(bs), perm, shared_perm); + + if (blk_insert_bs(blk, bs, errp) < 0) { + blk_unref(blk); + return NULL; + } + return blk; +} + +/* + * Creates a new BlockBackend, opens a new BlockDriverState, and connects both. + * The new BlockBackend is in the main AioContext. + * + * Just as with bdrv_open(), after having called this function the reference to + * @options belongs to the block layer (even on failure). + * + * TODO: Remove @filename and @flags; it should be possible to specify a whole + * BDS tree just by specifying the @options QDict (or @reference, + * alternatively). At the time of adding this function, this is not possible, + * though, so callers of this function have to be able to specify @filename and + * @flags. + */ +BlockBackend *blk_new_open(const char *filename, const char *reference, + QDict *options, int flags, Error **errp) +{ + BlockBackend *blk; + BlockDriverState *bs; + uint64_t perm = 0; + uint64_t shared = BLK_PERM_ALL; + + /* + * blk_new_open() is mainly used in .bdrv_create implementations and the + * tools where sharing isn't a major concern because the BDS stays private + * and the file is generally not supposed to be used by a second process, + * so we just request permission according to the flags. + * + * The exceptions are xen_disk and blockdev_init(); in these cases, the + * caller of blk_new_open() doesn't make use of the permissions, but they + * shouldn't hurt either. We can still share everything here because the + * guest devices will add their own blockers if they can't share. + */ + if ((flags & BDRV_O_NO_IO) == 0) { + perm |= BLK_PERM_CONSISTENT_READ; + if (flags & BDRV_O_RDWR) { + perm |= BLK_PERM_WRITE; + } + } + if (flags & BDRV_O_RESIZE) { + perm |= BLK_PERM_RESIZE; + } + if (flags & BDRV_O_NO_SHARE) { + shared = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED; + } + + blk = blk_new(qemu_get_aio_context(), perm, shared); + bs = bdrv_open(filename, reference, options, flags, errp); + if (!bs) { + blk_unref(blk); + return NULL; + } + + blk->root = bdrv_root_attach_child(bs, "root", &child_root, + BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, + perm, shared, blk, errp); + if (!blk->root) { + blk_unref(blk); + return NULL; + } + + return blk; +} + +static void blk_delete(BlockBackend *blk) +{ + assert(!blk->refcnt); + assert(!blk->name); + assert(!blk->dev); + if (blk->public.throttle_group_member.throttle_state) { + blk_io_limits_disable(blk); + } + if (blk->root) { + blk_remove_bs(blk); + } + if (blk->vmsh) { + qemu_del_vm_change_state_handler(blk->vmsh); + blk->vmsh = NULL; + } + assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers)); + assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers)); + assert(QLIST_EMPTY(&blk->aio_notifiers)); + QTAILQ_REMOVE(&block_backends, blk, link); + drive_info_del(blk->legacy_dinfo); + block_acct_cleanup(&blk->stats); + g_free(blk); +} + +static void drive_info_del(DriveInfo *dinfo) +{ + if (!dinfo) { + return; + } + qemu_opts_del(dinfo->opts); + g_free(dinfo); +} + +int blk_get_refcnt(BlockBackend *blk) +{ + return blk ? blk->refcnt : 0; +} + +/* + * Increment @blk's reference count. + * @blk must not be null. + */ +void blk_ref(BlockBackend *blk) +{ + assert(blk->refcnt > 0); + blk->refcnt++; +} + +/* + * Decrement @blk's reference count. + * If this drops it to zero, destroy @blk. + * For convenience, do nothing if @blk is null. + */ +void blk_unref(BlockBackend *blk) +{ + if (blk) { + assert(blk->refcnt > 0); + if (blk->refcnt > 1) { + blk->refcnt--; + } else { + blk_drain(blk); + /* blk_drain() cannot resurrect blk, nobody held a reference */ + assert(blk->refcnt == 1); + blk->refcnt = 0; + blk_delete(blk); + } + } +} + +/* + * Behaves similarly to blk_next() but iterates over all BlockBackends, even the + * ones which are hidden (i.e. are not referenced by the monitor). + */ +BlockBackend *blk_all_next(BlockBackend *blk) +{ + return blk ? QTAILQ_NEXT(blk, link) + : QTAILQ_FIRST(&block_backends); +} + +void blk_remove_all_bs(void) +{ + BlockBackend *blk = NULL; + + while ((blk = blk_all_next(blk)) != NULL) { + AioContext *ctx = blk_get_aio_context(blk); + + aio_context_acquire(ctx); + if (blk->root) { + blk_remove_bs(blk); + } + aio_context_release(ctx); + } +} + +/* + * Return the monitor-owned BlockBackend after @blk. + * If @blk is null, return the first one. + * Else, return @blk's next sibling, which may be null. + * + * To iterate over all BlockBackends, do + * for (blk = blk_next(NULL); blk; blk = blk_next(blk)) { + * ... + * } + */ +BlockBackend *blk_next(BlockBackend *blk) +{ + return blk ? QTAILQ_NEXT(blk, monitor_link) + : QTAILQ_FIRST(&monitor_block_backends); +} + +/* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by + * the monitor or attached to a BlockBackend */ +BlockDriverState *bdrv_next(BdrvNextIterator *it) +{ + BlockDriverState *bs, *old_bs; + + /* Must be called from the main loop */ + assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + + /* First, return all root nodes of BlockBackends. In order to avoid + * returning a BDS twice when multiple BBs refer to it, we only return it + * if the BB is the first one in the parent list of the BDS. */ + if (it->phase == BDRV_NEXT_BACKEND_ROOTS) { + BlockBackend *old_blk = it->blk; + + old_bs = old_blk ? blk_bs(old_blk) : NULL; + + do { + it->blk = blk_all_next(it->blk); + bs = it->blk ? blk_bs(it->blk) : NULL; + } while (it->blk && (bs == NULL || bdrv_first_blk(bs) != it->blk)); + + if (it->blk) { + blk_ref(it->blk); + } + blk_unref(old_blk); + + if (bs) { + bdrv_ref(bs); + bdrv_unref(old_bs); + return bs; + } + it->phase = BDRV_NEXT_MONITOR_OWNED; + } else { + old_bs = it->bs; + } + + /* Then return the monitor-owned BDSes without a BB attached. Ignore all + * BDSes that are attached to a BlockBackend here; they have been handled + * by the above block already */ + do { + it->bs = bdrv_next_monitor_owned(it->bs); + bs = it->bs; + } while (bs && bdrv_has_blk(bs)); + + if (bs) { + bdrv_ref(bs); + } + bdrv_unref(old_bs); + + return bs; +} + +static void bdrv_next_reset(BdrvNextIterator *it) +{ + *it = (BdrvNextIterator) { + .phase = BDRV_NEXT_BACKEND_ROOTS, + }; +} + +BlockDriverState *bdrv_first(BdrvNextIterator *it) +{ + bdrv_next_reset(it); + return bdrv_next(it); +} + +/* Must be called when aborting a bdrv_next() iteration before + * bdrv_next() returns NULL */ +void bdrv_next_cleanup(BdrvNextIterator *it) +{ + /* Must be called from the main loop */ + assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + + if (it->phase == BDRV_NEXT_BACKEND_ROOTS) { + if (it->blk) { + bdrv_unref(blk_bs(it->blk)); + blk_unref(it->blk); + } + } else { + bdrv_unref(it->bs); + } + + bdrv_next_reset(it); +} + +/* + * Add a BlockBackend into the list of backends referenced by the monitor, with + * the given @name acting as the handle for the monitor. + * Strictly for use by blockdev.c. + * + * @name must not be null or empty. + * + * Returns true on success and false on failure. In the latter case, an Error + * object is returned through @errp. + */ +bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp) +{ + assert(!blk->name); + assert(name && name[0]); + + if (!id_wellformed(name)) { + error_setg(errp, "Invalid device name"); + return false; + } + if (blk_by_name(name)) { + error_setg(errp, "Device with id '%s' already exists", name); + return false; + } + if (bdrv_find_node(name)) { + error_setg(errp, + "Device name '%s' conflicts with an existing node name", + name); + return false; + } + + blk->name = g_strdup(name); + QTAILQ_INSERT_TAIL(&monitor_block_backends, blk, monitor_link); + return true; +} + +/* + * Remove a BlockBackend from the list of backends referenced by the monitor. + * Strictly for use by blockdev.c. + */ +void monitor_remove_blk(BlockBackend *blk) +{ + if (!blk->name) { + return; + } + + QTAILQ_REMOVE(&monitor_block_backends, blk, monitor_link); + g_free(blk->name); + blk->name = NULL; +} + +/* + * Return @blk's name, a non-null string. + * Returns an empty string iff @blk is not referenced by the monitor. + */ +const char *blk_name(const BlockBackend *blk) +{ + return blk->name ?: ""; +} + +/* + * Return the BlockBackend with name @name if it exists, else null. + * @name must not be null. + */ +BlockBackend *blk_by_name(const char *name) +{ + BlockBackend *blk = NULL; + + assert(name); + while ((blk = blk_next(blk)) != NULL) { + if (!strcmp(name, blk->name)) { + return blk; + } + } + return NULL; +} + +/* + * Return the BlockDriverState attached to @blk if any, else null. + */ +BlockDriverState *blk_bs(BlockBackend *blk) +{ + return blk->root ? blk->root->bs : NULL; +} + +static BlockBackend *bdrv_first_blk(BlockDriverState *bs) +{ + BdrvChild *child; + QLIST_FOREACH(child, &bs->parents, next_parent) { + if (child->klass == &child_root) { + return child->opaque; + } + } + + return NULL; +} + +/* + * Returns true if @bs has an associated BlockBackend. + */ +bool bdrv_has_blk(BlockDriverState *bs) +{ + return bdrv_first_blk(bs) != NULL; +} + +/* + * Returns true if @bs has only BlockBackends as parents. + */ +bool bdrv_is_root_node(BlockDriverState *bs) +{ + BdrvChild *c; + + QLIST_FOREACH(c, &bs->parents, next_parent) { + if (c->klass != &child_root) { + return false; + } + } + + return true; +} + +/* + * Return @blk's DriveInfo if any, else null. + */ +DriveInfo *blk_legacy_dinfo(BlockBackend *blk) +{ + return blk->legacy_dinfo; +} + +/* + * Set @blk's DriveInfo to @dinfo, and return it. + * @blk must not have a DriveInfo set already. + * No other BlockBackend may have the same DriveInfo set. + */ +DriveInfo *blk_set_legacy_dinfo(BlockBackend *blk, DriveInfo *dinfo) +{ + assert(!blk->legacy_dinfo); + return blk->legacy_dinfo = dinfo; +} + +/* + * Return the BlockBackend with DriveInfo @dinfo. + * It must exist. + */ +BlockBackend *blk_by_legacy_dinfo(DriveInfo *dinfo) +{ + BlockBackend *blk = NULL; + + while ((blk = blk_next(blk)) != NULL) { + if (blk->legacy_dinfo == dinfo) { + return blk; + } + } + abort(); +} + +/* + * Returns a pointer to the publicly accessible fields of @blk. + */ +BlockBackendPublic *blk_get_public(BlockBackend *blk) +{ + return &blk->public; +} + +/* + * Returns a BlockBackend given the associated @public fields. + */ +BlockBackend *blk_by_public(BlockBackendPublic *public) +{ + return container_of(public, BlockBackend, public); +} + +/* + * Disassociates the currently associated BlockDriverState from @blk. + */ +void blk_remove_bs(BlockBackend *blk) +{ + ThrottleGroupMember *tgm = &blk->public.throttle_group_member; + BlockDriverState *bs; + BdrvChild *root; + + notifier_list_notify(&blk->remove_bs_notifiers, blk); + if (tgm->throttle_state) { + bs = blk_bs(blk); + bdrv_drained_begin(bs); + throttle_group_detach_aio_context(tgm); + throttle_group_attach_aio_context(tgm, qemu_get_aio_context()); + bdrv_drained_end(bs); + } + + blk_update_root_state(blk); + + /* bdrv_root_unref_child() will cause blk->root to become stale and may + * switch to a completion coroutine later on. Let's drain all I/O here + * to avoid that and a potential QEMU crash. + */ + blk_drain(blk); + root = blk->root; + blk->root = NULL; + bdrv_root_unref_child(root); +} + +/* + * Associates a new BlockDriverState with @blk. + */ +int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp) +{ + ThrottleGroupMember *tgm = &blk->public.throttle_group_member; + bdrv_ref(bs); + blk->root = bdrv_root_attach_child(bs, "root", &child_root, + BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, + blk->perm, blk->shared_perm, + blk, errp); + if (blk->root == NULL) { + return -EPERM; + } + + notifier_list_notify(&blk->insert_bs_notifiers, blk); + if (tgm->throttle_state) { + throttle_group_detach_aio_context(tgm); + throttle_group_attach_aio_context(tgm, bdrv_get_aio_context(bs)); + } + + return 0; +} + +/* + * Change BlockDriverState associated with @blk. + */ +int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp) +{ + return bdrv_replace_child_bs(blk->root, new_bs, errp); +} + +/* + * Sets the permission bitmasks that the user of the BlockBackend needs. + */ +int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm, + Error **errp) +{ + int ret; + + if (blk->root && !blk->disable_perm) { + ret = bdrv_child_try_set_perm(blk->root, perm, shared_perm, errp); + if (ret < 0) { + return ret; + } + } + + blk->perm = perm; + blk->shared_perm = shared_perm; + + return 0; +} + +void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm) +{ + *perm = blk->perm; + *shared_perm = blk->shared_perm; +} + +/* + * Attach device model @dev to @blk. + * Return 0 on success, -EBUSY when a device model is attached already. + */ +int blk_attach_dev(BlockBackend *blk, DeviceState *dev) +{ + if (blk->dev) { + return -EBUSY; + } + + /* While migration is still incoming, we don't need to apply the + * permissions of guest device BlockBackends. We might still have a block + * job or NBD server writing to the image for storage migration. */ + if (runstate_check(RUN_STATE_INMIGRATE)) { + blk->disable_perm = true; + } + + blk_ref(blk); + blk->dev = dev; + blk_iostatus_reset(blk); + + return 0; +} + +/* + * Detach device model @dev from @blk. + * @dev must be currently attached to @blk. + */ +void blk_detach_dev(BlockBackend *blk, DeviceState *dev) +{ + assert(blk->dev == dev); + blk->dev = NULL; + blk->dev_ops = NULL; + blk->dev_opaque = NULL; + blk->guest_block_size = 512; + blk_set_perm(blk, 0, BLK_PERM_ALL, &error_abort); + blk_unref(blk); +} + +/* + * Return the device model attached to @blk if any, else null. + */ +DeviceState *blk_get_attached_dev(BlockBackend *blk) +{ + return blk->dev; +} + +/* Return the qdev ID, or if no ID is assigned the QOM path, of the block + * device attached to the BlockBackend. */ +char *blk_get_attached_dev_id(BlockBackend *blk) +{ + DeviceState *dev = blk->dev; + + if (!dev) { + return g_strdup(""); + } else if (dev->id) { + return g_strdup(dev->id); + } + + return object_get_canonical_path(OBJECT(dev)) ?: g_strdup(""); +} + +/* + * Return the BlockBackend which has the device model @dev attached if it + * exists, else null. + * + * @dev must not be null. + */ +BlockBackend *blk_by_dev(void *dev) +{ + BlockBackend *blk = NULL; + + assert(dev != NULL); + while ((blk = blk_all_next(blk)) != NULL) { + if (blk->dev == dev) { + return blk; + } + } + return NULL; +} + +/* + * Set @blk's device model callbacks to @ops. + * @opaque is the opaque argument to pass to the callbacks. + * This is for use by device models. + */ +void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, + void *opaque) +{ + blk->dev_ops = ops; + blk->dev_opaque = opaque; + + /* Are we currently quiesced? Should we enforce this right now? */ + if (blk->quiesce_counter && ops->drained_begin) { + ops->drained_begin(opaque); + } +} + +/* + * Notify @blk's attached device model of media change. + * + * If @load is true, notify of media load. This action can fail, meaning that + * the medium cannot be loaded. @errp is set then. + * + * If @load is false, notify of media eject. This can never fail. + * + * Also send DEVICE_TRAY_MOVED events as appropriate. + */ +void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp) +{ + if (blk->dev_ops && blk->dev_ops->change_media_cb) { + bool tray_was_open, tray_is_open; + Error *local_err = NULL; + + tray_was_open = blk_dev_is_tray_open(blk); + blk->dev_ops->change_media_cb(blk->dev_opaque, load, &local_err); + if (local_err) { + assert(load == true); + error_propagate(errp, local_err); + return; + } + tray_is_open = blk_dev_is_tray_open(blk); + + if (tray_was_open != tray_is_open) { + char *id = blk_get_attached_dev_id(blk); + qapi_event_send_device_tray_moved(blk_name(blk), id, tray_is_open); + g_free(id); + } + } +} + +static void blk_root_change_media(BdrvChild *child, bool load) +{ + blk_dev_change_media_cb(child->opaque, load, NULL); +} + +/* + * Does @blk's attached device model have removable media? + * %true if no device model is attached. + */ +bool blk_dev_has_removable_media(BlockBackend *blk) +{ + return !blk->dev || (blk->dev_ops && blk->dev_ops->change_media_cb); +} + +/* + * Does @blk's attached device model have a tray? + */ +bool blk_dev_has_tray(BlockBackend *blk) +{ + return blk->dev_ops && blk->dev_ops->is_tray_open; +} + +/* + * Notify @blk's attached device model of a media eject request. + * If @force is true, the medium is about to be yanked out forcefully. + */ +void blk_dev_eject_request(BlockBackend *blk, bool force) +{ + if (blk->dev_ops && blk->dev_ops->eject_request_cb) { + blk->dev_ops->eject_request_cb(blk->dev_opaque, force); + } +} + +/* + * Does @blk's attached device model have a tray, and is it open? + */ +bool blk_dev_is_tray_open(BlockBackend *blk) +{ + if (blk_dev_has_tray(blk)) { + return blk->dev_ops->is_tray_open(blk->dev_opaque); + } + return false; +} + +/* + * Does @blk's attached device model have the medium locked? + * %false if the device model has no such lock. + */ +bool blk_dev_is_medium_locked(BlockBackend *blk) +{ + if (blk->dev_ops && blk->dev_ops->is_medium_locked) { + return blk->dev_ops->is_medium_locked(blk->dev_opaque); + } + return false; +} + +/* + * Notify @blk's attached device model of a backend size change. + */ +static void blk_root_resize(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + + if (blk->dev_ops && blk->dev_ops->resize_cb) { + blk->dev_ops->resize_cb(blk->dev_opaque); + } +} + +void blk_iostatus_enable(BlockBackend *blk) +{ + blk->iostatus_enabled = true; + blk->iostatus = BLOCK_DEVICE_IO_STATUS_OK; +} + +/* The I/O status is only enabled if the drive explicitly + * enables it _and_ the VM is configured to stop on errors */ +bool blk_iostatus_is_enabled(const BlockBackend *blk) +{ + return (blk->iostatus_enabled && + (blk->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC || + blk->on_write_error == BLOCKDEV_ON_ERROR_STOP || + blk->on_read_error == BLOCKDEV_ON_ERROR_STOP)); +} + +BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk) +{ + return blk->iostatus; +} + +void blk_iostatus_disable(BlockBackend *blk) +{ + blk->iostatus_enabled = false; +} + +void blk_iostatus_reset(BlockBackend *blk) +{ + if (blk_iostatus_is_enabled(blk)) { + blk->iostatus = BLOCK_DEVICE_IO_STATUS_OK; + } +} + +void blk_iostatus_set_err(BlockBackend *blk, int error) +{ + assert(blk_iostatus_is_enabled(blk)); + if (blk->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { + blk->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : + BLOCK_DEVICE_IO_STATUS_FAILED; + } +} + +void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow) +{ + blk->allow_write_beyond_eof = allow; +} + +void blk_set_allow_aio_context_change(BlockBackend *blk, bool allow) +{ + blk->allow_aio_context_change = allow; +} + +void blk_set_disable_request_queuing(BlockBackend *blk, bool disable) +{ + blk->disable_request_queuing = disable; +} + +static int blk_check_byte_request(BlockBackend *blk, int64_t offset, + int64_t bytes) +{ + int64_t len; + + if (bytes < 0) { + return -EIO; + } + + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + if (offset < 0) { + return -EIO; + } + + if (!blk->allow_write_beyond_eof) { + len = blk_getlength(blk); + if (len < 0) { + return len; + } + + if (offset > len || len - offset < bytes) { + return -EIO; + } + } + + return 0; +} + +/* To be called between exactly one pair of blk_inc/dec_in_flight() */ +static void coroutine_fn blk_wait_while_drained(BlockBackend *blk) +{ + assert(blk->in_flight > 0); + + if (blk->quiesce_counter && !blk->disable_request_queuing) { + blk_dec_in_flight(blk); + qemu_co_queue_wait(&blk->queued_requests, NULL); + blk_inc_in_flight(blk); + } +} + +/* To be called between exactly one pair of blk_inc/dec_in_flight() */ +int coroutine_fn +blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, BdrvRequestFlags flags) +{ + int ret; + BlockDriverState *bs; + + blk_wait_while_drained(blk); + + /* Call blk_bs() only after waiting, the graph may have changed */ + bs = blk_bs(blk); + trace_blk_co_preadv(blk, bs, offset, bytes, flags); + + ret = blk_check_byte_request(blk, offset, bytes); + if (ret < 0) { + return ret; + } + + bdrv_inc_in_flight(bs); + + /* throttling disk I/O */ + if (blk->public.throttle_group_member.throttle_state) { + throttle_group_co_io_limits_intercept(&blk->public.throttle_group_member, + bytes, false); + } + + ret = bdrv_co_preadv(blk->root, offset, bytes, qiov, flags); + bdrv_dec_in_flight(bs); + return ret; +} + +int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset, + int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_co_do_preadv(blk, offset, bytes, qiov, flags); + blk_dec_in_flight(blk); + + return ret; +} + +/* To be called between exactly one pair of blk_inc/dec_in_flight() */ +int coroutine_fn +blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, + BdrvRequestFlags flags) +{ + int ret; + BlockDriverState *bs; + + blk_wait_while_drained(blk); + + /* Call blk_bs() only after waiting, the graph may have changed */ + bs = blk_bs(blk); + trace_blk_co_pwritev(blk, bs, offset, bytes, flags); + + ret = blk_check_byte_request(blk, offset, bytes); + if (ret < 0) { + return ret; + } + + bdrv_inc_in_flight(bs); + /* throttling disk I/O */ + if (blk->public.throttle_group_member.throttle_state) { + throttle_group_co_io_limits_intercept(&blk->public.throttle_group_member, + bytes, true); + } + + if (!blk->enable_write_cache) { + flags |= BDRV_REQ_FUA; + } + + ret = bdrv_co_pwritev_part(blk->root, offset, bytes, qiov, qiov_offset, + flags); + bdrv_dec_in_flight(bs); + return ret; +} + +int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset, + int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, + BdrvRequestFlags flags) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_co_do_pwritev_part(blk, offset, bytes, qiov, qiov_offset, flags); + blk_dec_in_flight(blk); + + return ret; +} + +int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset, + int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags) +{ + return blk_co_pwritev_part(blk, offset, bytes, qiov, 0, flags); +} + +static int coroutine_fn blk_pwritev_part(BlockBackend *blk, int64_t offset, + int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, + BdrvRequestFlags flags) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_do_pwritev_part(blk, offset, bytes, qiov, qiov_offset, flags); + blk_dec_in_flight(blk); + + return ret; +} + +typedef struct BlkRwCo { + BlockBackend *blk; + int64_t offset; + void *iobuf; + int ret; + BdrvRequestFlags flags; +} BlkRwCo; + +int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset, + int64_t bytes, BdrvRequestFlags flags) +{ + return blk_pwritev_part(blk, offset, bytes, NULL, 0, + flags | BDRV_REQ_ZERO_WRITE); +} + +int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags) +{ + return bdrv_make_zero(blk->root, flags); +} + +void blk_inc_in_flight(BlockBackend *blk) +{ + qatomic_inc(&blk->in_flight); +} + +void blk_dec_in_flight(BlockBackend *blk) +{ + qatomic_dec(&blk->in_flight); + aio_wait_kick(); +} + +static void error_callback_bh(void *opaque) +{ + struct BlockBackendAIOCB *acb = opaque; + + blk_dec_in_flight(acb->blk); + acb->common.cb(acb->common.opaque, acb->ret); + qemu_aio_unref(acb); +} + +BlockAIOCB *blk_abort_aio_request(BlockBackend *blk, + BlockCompletionFunc *cb, + void *opaque, int ret) +{ + struct BlockBackendAIOCB *acb; + + blk_inc_in_flight(blk); + acb = blk_aio_get(&block_backend_aiocb_info, blk, cb, opaque); + acb->blk = blk; + acb->ret = ret; + + replay_bh_schedule_oneshot_event(blk_get_aio_context(blk), + error_callback_bh, acb); + return &acb->common; +} + +typedef struct BlkAioEmAIOCB { + BlockAIOCB common; + BlkRwCo rwco; + int64_t bytes; + bool has_returned; +} BlkAioEmAIOCB; + +static AioContext *blk_aio_em_aiocb_get_aio_context(BlockAIOCB *acb_) +{ + BlkAioEmAIOCB *acb = container_of(acb_, BlkAioEmAIOCB, common); + + return blk_get_aio_context(acb->rwco.blk); +} + +static const AIOCBInfo blk_aio_em_aiocb_info = { + .aiocb_size = sizeof(BlkAioEmAIOCB), + .get_aio_context = blk_aio_em_aiocb_get_aio_context, +}; + +static void blk_aio_complete(BlkAioEmAIOCB *acb) +{ + if (acb->has_returned) { + acb->common.cb(acb->common.opaque, acb->rwco.ret); + blk_dec_in_flight(acb->rwco.blk); + qemu_aio_unref(acb); + } +} + +static void blk_aio_complete_bh(void *opaque) +{ + BlkAioEmAIOCB *acb = opaque; + assert(acb->has_returned); + blk_aio_complete(acb); +} + +static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, + int64_t bytes, + void *iobuf, CoroutineEntry co_entry, + BdrvRequestFlags flags, + BlockCompletionFunc *cb, void *opaque) +{ + BlkAioEmAIOCB *acb; + Coroutine *co; + + blk_inc_in_flight(blk); + acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque); + acb->rwco = (BlkRwCo) { + .blk = blk, + .offset = offset, + .iobuf = iobuf, + .flags = flags, + .ret = NOT_DONE, + }; + acb->bytes = bytes; + acb->has_returned = false; + + co = qemu_coroutine_create(co_entry, acb); + bdrv_coroutine_enter(blk_bs(blk), co); + + acb->has_returned = true; + if (acb->rwco.ret != NOT_DONE) { + replay_bh_schedule_oneshot_event(blk_get_aio_context(blk), + blk_aio_complete_bh, acb); + } + + return &acb->common; +} + +static void blk_aio_read_entry(void *opaque) +{ + BlkAioEmAIOCB *acb = opaque; + BlkRwCo *rwco = &acb->rwco; + QEMUIOVector *qiov = rwco->iobuf; + + assert(qiov->size == acb->bytes); + rwco->ret = blk_co_do_preadv(rwco->blk, rwco->offset, acb->bytes, + qiov, rwco->flags); + blk_aio_complete(acb); +} + +static void blk_aio_write_entry(void *opaque) +{ + BlkAioEmAIOCB *acb = opaque; + BlkRwCo *rwco = &acb->rwco; + QEMUIOVector *qiov = rwco->iobuf; + + assert(!qiov || qiov->size == acb->bytes); + rwco->ret = blk_co_do_pwritev_part(rwco->blk, rwco->offset, acb->bytes, + qiov, 0, rwco->flags); + blk_aio_complete(acb); +} + +BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset, + int64_t bytes, BdrvRequestFlags flags, + BlockCompletionFunc *cb, void *opaque) +{ + return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_write_entry, + flags | BDRV_REQ_ZERO_WRITE, cb, opaque); +} + +int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes) +{ + int ret; + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); + + blk_inc_in_flight(blk); + ret = blk_do_preadv(blk, offset, bytes, &qiov, 0); + blk_dec_in_flight(blk); + + return ret < 0 ? ret : bytes; +} + +int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes, + BdrvRequestFlags flags) +{ + int ret; + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); + + ret = blk_pwritev_part(blk, offset, bytes, &qiov, 0, flags); + + return ret < 0 ? ret : bytes; +} + +int64_t blk_getlength(BlockBackend *blk) +{ + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_getlength(blk_bs(blk)); +} + +void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr) +{ + if (!blk_bs(blk)) { + *nb_sectors_ptr = 0; + } else { + bdrv_get_geometry(blk_bs(blk), nb_sectors_ptr); + } +} + +int64_t blk_nb_sectors(BlockBackend *blk) +{ + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_nb_sectors(blk_bs(blk)); +} + +BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset, + QEMUIOVector *qiov, BdrvRequestFlags flags, + BlockCompletionFunc *cb, void *opaque) +{ + assert((uint64_t)qiov->size <= INT64_MAX); + return blk_aio_prwv(blk, offset, qiov->size, qiov, + blk_aio_read_entry, flags, cb, opaque); +} + +BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset, + QEMUIOVector *qiov, BdrvRequestFlags flags, + BlockCompletionFunc *cb, void *opaque) +{ + assert((uint64_t)qiov->size <= INT64_MAX); + return blk_aio_prwv(blk, offset, qiov->size, qiov, + blk_aio_write_entry, flags, cb, opaque); +} + +void blk_aio_cancel(BlockAIOCB *acb) +{ + bdrv_aio_cancel(acb); +} + +void blk_aio_cancel_async(BlockAIOCB *acb) +{ + bdrv_aio_cancel_async(acb); +} + +/* To be called between exactly one pair of blk_inc/dec_in_flight() */ +int coroutine_fn +blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf) +{ + blk_wait_while_drained(blk); + + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_co_ioctl(blk_bs(blk), req, buf); +} + +int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_do_ioctl(blk, req, buf); + blk_dec_in_flight(blk); + + return ret; +} + +static void blk_aio_ioctl_entry(void *opaque) +{ + BlkAioEmAIOCB *acb = opaque; + BlkRwCo *rwco = &acb->rwco; + + rwco->ret = blk_co_do_ioctl(rwco->blk, rwco->offset, rwco->iobuf); + + blk_aio_complete(acb); +} + +BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf, + BlockCompletionFunc *cb, void *opaque) +{ + return blk_aio_prwv(blk, req, 0, buf, blk_aio_ioctl_entry, 0, cb, opaque); +} + +/* To be called between exactly one pair of blk_inc/dec_in_flight() */ +int coroutine_fn +blk_co_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes) +{ + int ret; + + blk_wait_while_drained(blk); + + ret = blk_check_byte_request(blk, offset, bytes); + if (ret < 0) { + return ret; + } + + return bdrv_co_pdiscard(blk->root, offset, bytes); +} + +static void blk_aio_pdiscard_entry(void *opaque) +{ + BlkAioEmAIOCB *acb = opaque; + BlkRwCo *rwco = &acb->rwco; + + rwco->ret = blk_co_do_pdiscard(rwco->blk, rwco->offset, acb->bytes); + blk_aio_complete(acb); +} + +BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, + int64_t offset, int64_t bytes, + BlockCompletionFunc *cb, void *opaque) +{ + return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_pdiscard_entry, 0, + cb, opaque); +} + +int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset, + int64_t bytes) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_co_do_pdiscard(blk, offset, bytes); + blk_dec_in_flight(blk); + + return ret; +} + +int blk_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_do_pdiscard(blk, offset, bytes); + blk_dec_in_flight(blk); + + return ret; +} + +/* To be called between exactly one pair of blk_inc/dec_in_flight() */ +int coroutine_fn blk_co_do_flush(BlockBackend *blk) +{ + blk_wait_while_drained(blk); + + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_co_flush(blk_bs(blk)); +} + +static void blk_aio_flush_entry(void *opaque) +{ + BlkAioEmAIOCB *acb = opaque; + BlkRwCo *rwco = &acb->rwco; + + rwco->ret = blk_co_do_flush(rwco->blk); + blk_aio_complete(acb); +} + +BlockAIOCB *blk_aio_flush(BlockBackend *blk, + BlockCompletionFunc *cb, void *opaque) +{ + return blk_aio_prwv(blk, 0, 0, NULL, blk_aio_flush_entry, 0, cb, opaque); +} + +int coroutine_fn blk_co_flush(BlockBackend *blk) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_co_do_flush(blk); + blk_dec_in_flight(blk); + + return ret; +} + +int blk_flush(BlockBackend *blk) +{ + int ret; + + blk_inc_in_flight(blk); + ret = blk_do_flush(blk); + blk_dec_in_flight(blk); + + return ret; +} + +void blk_drain(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_drained_begin(bs); + } + + /* We may have -ENOMEDIUM completions in flight */ + AIO_WAIT_WHILE(blk_get_aio_context(blk), + qatomic_mb_read(&blk->in_flight) > 0); + + if (bs) { + bdrv_drained_end(bs); + } +} + +void blk_drain_all(void) +{ + BlockBackend *blk = NULL; + + bdrv_drain_all_begin(); + + while ((blk = blk_all_next(blk)) != NULL) { + AioContext *ctx = blk_get_aio_context(blk); + + aio_context_acquire(ctx); + + /* We may have -ENOMEDIUM completions in flight */ + AIO_WAIT_WHILE(ctx, qatomic_mb_read(&blk->in_flight) > 0); + + aio_context_release(ctx); + } + + bdrv_drain_all_end(); +} + +void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error, + BlockdevOnError on_write_error) +{ + blk->on_read_error = on_read_error; + blk->on_write_error = on_write_error; +} + +BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read) +{ + return is_read ? blk->on_read_error : blk->on_write_error; +} + +BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read, + int error) +{ + BlockdevOnError on_err = blk_get_on_error(blk, is_read); + + switch (on_err) { + case BLOCKDEV_ON_ERROR_ENOSPC: + return (error == ENOSPC) ? + BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT; + case BLOCKDEV_ON_ERROR_STOP: + return BLOCK_ERROR_ACTION_STOP; + case BLOCKDEV_ON_ERROR_REPORT: + return BLOCK_ERROR_ACTION_REPORT; + case BLOCKDEV_ON_ERROR_IGNORE: + return BLOCK_ERROR_ACTION_IGNORE; + case BLOCKDEV_ON_ERROR_AUTO: + default: + abort(); + } +} + +static void send_qmp_error_event(BlockBackend *blk, + BlockErrorAction action, + bool is_read, int error) +{ + IoOperationType optype; + BlockDriverState *bs = blk_bs(blk); + + optype = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE; + qapi_event_send_block_io_error(blk_name(blk), !!bs, + bs ? bdrv_get_node_name(bs) : NULL, optype, + action, blk_iostatus_is_enabled(blk), + error == ENOSPC, strerror(error)); +} + +/* This is done by device models because, while the block layer knows + * about the error, it does not know whether an operation comes from + * the device or the block layer (from a job, for example). + */ +void blk_error_action(BlockBackend *blk, BlockErrorAction action, + bool is_read, int error) +{ + assert(error >= 0); + + if (action == BLOCK_ERROR_ACTION_STOP) { + /* First set the iostatus, so that "info block" returns an iostatus + * that matches the events raised so far (an additional error iostatus + * is fine, but not a lost one). + */ + blk_iostatus_set_err(blk, error); + + /* Then raise the request to stop the VM and the event. + * qemu_system_vmstop_request_prepare has two effects. First, + * it ensures that the STOP event always comes after the + * BLOCK_IO_ERROR event. Second, it ensures that even if management + * can observe the STOP event and do a "cont" before the STOP + * event is issued, the VM will not stop. In this case, vm_start() + * also ensures that the STOP/RESUME pair of events is emitted. + */ + qemu_system_vmstop_request_prepare(); + send_qmp_error_event(blk, action, is_read, error); + qemu_system_vmstop_request(RUN_STATE_IO_ERROR); + } else { + send_qmp_error_event(blk, action, is_read, error); + } +} + +/* + * Returns true if the BlockBackend can support taking write permissions + * (because its root node is not read-only). + */ +bool blk_supports_write_perm(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + return !bdrv_is_read_only(bs); + } else { + return blk->root_state.open_flags & BDRV_O_RDWR; + } +} + +/* + * Returns true if the BlockBackend can be written to in its current + * configuration (i.e. if write permission have been requested) + */ +bool blk_is_writable(BlockBackend *blk) +{ + return blk->perm & BLK_PERM_WRITE; +} + +bool blk_is_sg(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (!bs) { + return false; + } + + return bdrv_is_sg(bs); +} + +bool blk_enable_write_cache(BlockBackend *blk) +{ + return blk->enable_write_cache; +} + +void blk_set_enable_write_cache(BlockBackend *blk, bool wce) +{ + blk->enable_write_cache = wce; +} + +void blk_invalidate_cache(BlockBackend *blk, Error **errp) +{ + BlockDriverState *bs = blk_bs(blk); + + if (!bs) { + error_setg(errp, "Device '%s' has no medium", blk->name); + return; + } + + bdrv_invalidate_cache(bs, errp); +} + +bool blk_is_inserted(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + return bs && bdrv_is_inserted(bs); +} + +bool blk_is_available(BlockBackend *blk) +{ + return blk_is_inserted(blk) && !blk_dev_is_tray_open(blk); +} + +void blk_lock_medium(BlockBackend *blk, bool locked) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_lock_medium(bs, locked); + } +} + +void blk_eject(BlockBackend *blk, bool eject_flag) +{ + BlockDriverState *bs = blk_bs(blk); + char *id; + + if (bs) { + bdrv_eject(bs, eject_flag); + } + + /* Whether or not we ejected on the backend, + * the frontend experienced a tray event. */ + id = blk_get_attached_dev_id(blk); + qapi_event_send_device_tray_moved(blk_name(blk), id, + eject_flag); + g_free(id); +} + +int blk_get_flags(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + return bdrv_get_flags(bs); + } else { + return blk->root_state.open_flags; + } +} + +/* Returns the minimum request alignment, in bytes; guaranteed nonzero */ +uint32_t blk_get_request_alignment(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + return bs ? bs->bl.request_alignment : BDRV_SECTOR_SIZE; +} + +/* Returns the maximum hardware transfer length, in bytes; guaranteed nonzero */ +uint64_t blk_get_max_hw_transfer(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + uint64_t max = INT_MAX; + + if (bs) { + max = MIN_NON_ZERO(max, bs->bl.max_hw_transfer); + max = MIN_NON_ZERO(max, bs->bl.max_transfer); + } + return ROUND_DOWN(max, blk_get_request_alignment(blk)); +} + +/* Returns the maximum transfer length, in bytes; guaranteed nonzero */ +uint32_t blk_get_max_transfer(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + uint32_t max = INT_MAX; + + if (bs) { + max = MIN_NON_ZERO(max, bs->bl.max_transfer); + } + return ROUND_DOWN(max, blk_get_request_alignment(blk)); +} + +int blk_get_max_hw_iov(BlockBackend *blk) +{ + return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov, + blk->root->bs->bl.max_iov); +} + +int blk_get_max_iov(BlockBackend *blk) +{ + return blk->root->bs->bl.max_iov; +} + +void blk_set_guest_block_size(BlockBackend *blk, int align) +{ + blk->guest_block_size = align; +} + +void *blk_try_blockalign(BlockBackend *blk, size_t size) +{ + return qemu_try_blockalign(blk ? blk_bs(blk) : NULL, size); +} + +void *blk_blockalign(BlockBackend *blk, size_t size) +{ + return qemu_blockalign(blk ? blk_bs(blk) : NULL, size); +} + +bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp) +{ + BlockDriverState *bs = blk_bs(blk); + + if (!bs) { + return false; + } + + return bdrv_op_is_blocked(bs, op, errp); +} + +void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_op_unblock(bs, op, reason); + } +} + +void blk_op_block_all(BlockBackend *blk, Error *reason) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_op_block_all(bs, reason); + } +} + +void blk_op_unblock_all(BlockBackend *blk, Error *reason) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_op_unblock_all(bs, reason); + } +} + +AioContext *blk_get_aio_context(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + AioContext *ctx = bdrv_get_aio_context(blk_bs(blk)); + assert(ctx == blk->ctx); + } + + return blk->ctx; +} + +static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb) +{ + BlockBackendAIOCB *blk_acb = DO_UPCAST(BlockBackendAIOCB, common, acb); + return blk_get_aio_context(blk_acb->blk); +} + +static int blk_do_set_aio_context(BlockBackend *blk, AioContext *new_context, + bool update_root_node, Error **errp) +{ + BlockDriverState *bs = blk_bs(blk); + ThrottleGroupMember *tgm = &blk->public.throttle_group_member; + int ret; + + if (bs) { + if (update_root_node) { + ret = bdrv_child_try_set_aio_context(bs, new_context, blk->root, + errp); + if (ret < 0) { + return ret; + } + } + if (tgm->throttle_state) { + bdrv_drained_begin(bs); + throttle_group_detach_aio_context(tgm); + throttle_group_attach_aio_context(tgm, new_context); + bdrv_drained_end(bs); + } + } + + blk->ctx = new_context; + return 0; +} + +int blk_set_aio_context(BlockBackend *blk, AioContext *new_context, + Error **errp) +{ + return blk_do_set_aio_context(blk, new_context, true, errp); +} + +static bool blk_root_can_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore, Error **errp) +{ + BlockBackend *blk = child->opaque; + + if (blk->allow_aio_context_change) { + return true; + } + + /* Only manually created BlockBackends that are not attached to anything + * can change their AioContext without updating their user. */ + if (!blk->name || blk->dev) { + /* TODO Add BB name/QOM path */ + error_setg(errp, "Cannot change iothread of active block backend"); + return false; + } + + return true; +} + +static void blk_root_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore) +{ + BlockBackend *blk = child->opaque; + blk_do_set_aio_context(blk, ctx, false, &error_abort); +} + +void blk_add_aio_context_notifier(BlockBackend *blk, + void (*attached_aio_context)(AioContext *new_context, void *opaque), + void (*detach_aio_context)(void *opaque), void *opaque) +{ + BlockBackendAioNotifier *notifier; + BlockDriverState *bs = blk_bs(blk); + + notifier = g_new(BlockBackendAioNotifier, 1); + notifier->attached_aio_context = attached_aio_context; + notifier->detach_aio_context = detach_aio_context; + notifier->opaque = opaque; + QLIST_INSERT_HEAD(&blk->aio_notifiers, notifier, list); + + if (bs) { + bdrv_add_aio_context_notifier(bs, attached_aio_context, + detach_aio_context, opaque); + } +} + +void blk_remove_aio_context_notifier(BlockBackend *blk, + void (*attached_aio_context)(AioContext *, + void *), + void (*detach_aio_context)(void *), + void *opaque) +{ + BlockBackendAioNotifier *notifier; + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_remove_aio_context_notifier(bs, attached_aio_context, + detach_aio_context, opaque); + } + + QLIST_FOREACH(notifier, &blk->aio_notifiers, list) { + if (notifier->attached_aio_context == attached_aio_context && + notifier->detach_aio_context == detach_aio_context && + notifier->opaque == opaque) { + QLIST_REMOVE(notifier, list); + g_free(notifier); + return; + } + } + + abort(); +} + +void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify) +{ + notifier_list_add(&blk->remove_bs_notifiers, notify); +} + +void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify) +{ + notifier_list_add(&blk->insert_bs_notifiers, notify); +} + +void blk_io_plug(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_io_plug(bs); + } +} + +void blk_io_unplug(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + + if (bs) { + bdrv_io_unplug(bs); + } +} + +BlockAcctStats *blk_get_stats(BlockBackend *blk) +{ + return &blk->stats; +} + +void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk, + BlockCompletionFunc *cb, void *opaque) +{ + return qemu_aio_get(aiocb_info, blk_bs(blk), cb, opaque); +} + +int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset, + int64_t bytes, BdrvRequestFlags flags) +{ + return blk_co_pwritev(blk, offset, bytes, NULL, + flags | BDRV_REQ_ZERO_WRITE); +} + +int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf, + int64_t bytes) +{ + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); + return blk_pwritev_part(blk, offset, bytes, &qiov, 0, + BDRV_REQ_WRITE_COMPRESSED); +} + +int blk_truncate(BlockBackend *blk, int64_t offset, bool exact, + PreallocMode prealloc, BdrvRequestFlags flags, Error **errp) +{ + if (!blk_is_available(blk)) { + error_setg(errp, "No medium inserted"); + return -ENOMEDIUM; + } + + return bdrv_truncate(blk->root, offset, exact, prealloc, flags, errp); +} + +int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf, + int64_t pos, int size) +{ + int ret; + + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + ret = bdrv_save_vmstate(blk_bs(blk), buf, pos, size); + if (ret < 0) { + return ret; + } + + if (ret == size && !blk->enable_write_cache) { + ret = bdrv_flush(blk_bs(blk)); + } + + return ret < 0 ? ret : size; +} + +int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size) +{ + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_load_vmstate(blk_bs(blk), buf, pos, size); +} + +int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz) +{ + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_probe_blocksizes(blk_bs(blk), bsz); +} + +int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo) +{ + if (!blk_is_available(blk)) { + return -ENOMEDIUM; + } + + return bdrv_probe_geometry(blk_bs(blk), geo); +} + +/* + * Updates the BlockBackendRootState object with data from the currently + * attached BlockDriverState. + */ +void blk_update_root_state(BlockBackend *blk) +{ + assert(blk->root); + + blk->root_state.open_flags = blk->root->bs->open_flags; + blk->root_state.detect_zeroes = blk->root->bs->detect_zeroes; +} + +/* + * Returns the detect-zeroes setting to be used for bdrv_open() of a + * BlockDriverState which is supposed to inherit the root state. + */ +bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk) +{ + return blk->root_state.detect_zeroes; +} + +/* + * Returns the flags to be used for bdrv_open() of a BlockDriverState which is + * supposed to inherit the root state. + */ +int blk_get_open_flags_from_root_state(BlockBackend *blk) +{ + return blk->root_state.open_flags; +} + +BlockBackendRootState *blk_get_root_state(BlockBackend *blk) +{ + return &blk->root_state; +} + +int blk_commit_all(void) +{ + BlockBackend *blk = NULL; + + while ((blk = blk_all_next(blk)) != NULL) { + AioContext *aio_context = blk_get_aio_context(blk); + BlockDriverState *unfiltered_bs = bdrv_skip_filters(blk_bs(blk)); + + aio_context_acquire(aio_context); + if (blk_is_inserted(blk) && bdrv_cow_child(unfiltered_bs)) { + int ret; + + ret = bdrv_commit(unfiltered_bs); + if (ret < 0) { + aio_context_release(aio_context); + return ret; + } + } + aio_context_release(aio_context); + } + return 0; +} + + +/* throttling disk I/O limits */ +void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg) +{ + throttle_group_config(&blk->public.throttle_group_member, cfg); +} + +void blk_io_limits_disable(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + ThrottleGroupMember *tgm = &blk->public.throttle_group_member; + assert(tgm->throttle_state); + if (bs) { + bdrv_drained_begin(bs); + } + throttle_group_unregister_tgm(tgm); + if (bs) { + bdrv_drained_end(bs); + } +} + +/* should be called before blk_set_io_limits if a limit is set */ +void blk_io_limits_enable(BlockBackend *blk, const char *group) +{ + assert(!blk->public.throttle_group_member.throttle_state); + throttle_group_register_tgm(&blk->public.throttle_group_member, + group, blk_get_aio_context(blk)); +} + +void blk_io_limits_update_group(BlockBackend *blk, const char *group) +{ + /* this BB is not part of any group */ + if (!blk->public.throttle_group_member.throttle_state) { + return; + } + + /* this BB is a part of the same group than the one we want */ + if (!g_strcmp0(throttle_group_get_name(&blk->public.throttle_group_member), + group)) { + return; + } + + /* need to change the group this bs belong to */ + blk_io_limits_disable(blk); + blk_io_limits_enable(blk, group); +} + +static void blk_root_drained_begin(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + ThrottleGroupMember *tgm = &blk->public.throttle_group_member; + + if (++blk->quiesce_counter == 1) { + if (blk->dev_ops && blk->dev_ops->drained_begin) { + blk->dev_ops->drained_begin(blk->dev_opaque); + } + } + + /* Note that blk->root may not be accessible here yet if we are just + * attaching to a BlockDriverState that is drained. Use child instead. */ + + if (qatomic_fetch_inc(&tgm->io_limits_disabled) == 0) { + throttle_group_restart_tgm(tgm); + } +} + +static bool blk_root_drained_poll(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + bool busy = false; + assert(blk->quiesce_counter); + + if (blk->dev_ops && blk->dev_ops->drained_poll) { + busy = blk->dev_ops->drained_poll(blk->dev_opaque); + } + return busy || !!blk->in_flight; +} + +static void blk_root_drained_end(BdrvChild *child, int *drained_end_counter) +{ + BlockBackend *blk = child->opaque; + assert(blk->quiesce_counter); + + assert(blk->public.throttle_group_member.io_limits_disabled); + qatomic_dec(&blk->public.throttle_group_member.io_limits_disabled); + + if (--blk->quiesce_counter == 0) { + if (blk->dev_ops && blk->dev_ops->drained_end) { + blk->dev_ops->drained_end(blk->dev_opaque); + } + while (qemu_co_enter_next(&blk->queued_requests, NULL)) { + /* Resume all queued requests */ + } + } +} + +void blk_register_buf(BlockBackend *blk, void *host, size_t size) +{ + bdrv_register_buf(blk_bs(blk), host, size); +} + +void blk_unregister_buf(BlockBackend *blk, void *host) +{ + bdrv_unregister_buf(blk_bs(blk), host); +} + +int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in, + BlockBackend *blk_out, int64_t off_out, + int64_t bytes, BdrvRequestFlags read_flags, + BdrvRequestFlags write_flags) +{ + int r; + r = blk_check_byte_request(blk_in, off_in, bytes); + if (r) { + return r; + } + r = blk_check_byte_request(blk_out, off_out, bytes); + if (r) { + return r; + } + return bdrv_co_copy_range(blk_in->root, off_in, + blk_out->root, off_out, + bytes, read_flags, write_flags); +} + +const BdrvChild *blk_root(BlockBackend *blk) +{ + return blk->root; +} + +int blk_make_empty(BlockBackend *blk, Error **errp) +{ + if (!blk_is_available(blk)) { + error_setg(errp, "No medium inserted"); + return -ENOMEDIUM; + } + + return bdrv_make_empty(blk->root, errp); +} |