/* * QEMU Block backends * * Copyright (C) 2014-2016 Red Hat, Inc. * * Authors: * Markus Armbruster , * * 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; uint64_t saved_shared_perm; if (!blk->disable_perm) { return; } blk->disable_perm = false; /* * blk->shared_perm contains the permissions we want to share once * migration is really completely done. For now, we need to share * all; but we also need to retain blk->shared_perm, which is * overwritten by a successful blk_set_perm() call. Save it and * restore it below. */ saved_shared_perm = blk->shared_perm; blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err); if (local_err) { error_propagate(errp, local_err); blk->disable_perm = true; return; } blk->shared_perm = saved_shared_perm; 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; BdrvChild *root; notifier_list_notify(&blk->remove_bs_notifiers, blk); if (tgm->throttle_state) { BlockDriverState *bs = blk_bs(blk); /* * Take a ref in case blk_bs() changes across bdrv_drained_begin(), for * example, if a temporary filter node is removed by a blockjob. */ bdrv_ref(bs); bdrv_drained_begin(bs); throttle_group_detach_aio_context(tgm); throttle_group_attach_aio_context(tgm, qemu_get_aio_context()); bdrv_drained_end(bs); bdrv_unref(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_ref(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); bdrv_unref(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_activate(BlockBackend *blk, Error **errp) { BlockDriverState *bs = blk_bs(blk); if (!bs) { error_setg(errp, "Device '%s' has no medium", blk->name); return; } bdrv_activate(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) { bdrv_ref(bs); if (update_root_node) { ret = bdrv_child_try_set_aio_context(bs, new_context, blk->root, errp); if (ret < 0) { bdrv_unref(bs); 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); } bdrv_unref(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_ref(bs); bdrv_drained_begin(bs); } throttle_group_unregister_tgm(tgm); if (bs) { bdrv_drained_end(bs); bdrv_unref(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); }