1314 lines
49 KiB
C
1314 lines
49 KiB
C
/*
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* QEMU System Emulator block driver
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef BLOCK_INT_COMMON_H
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#define BLOCK_INT_COMMON_H
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#include "block/aio.h"
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#include "block/block-common.h"
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#include "block/block-global-state.h"
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#include "block/snapshot.h"
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#include "qemu/iov.h"
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#include "qemu/rcu.h"
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#include "qemu/stats64.h"
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#define BLOCK_FLAG_LAZY_REFCOUNTS 8
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#define BLOCK_OPT_SIZE "size"
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#define BLOCK_OPT_ENCRYPT "encryption"
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#define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format"
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#define BLOCK_OPT_COMPAT6 "compat6"
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#define BLOCK_OPT_HWVERSION "hwversion"
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#define BLOCK_OPT_BACKING_FILE "backing_file"
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#define BLOCK_OPT_BACKING_FMT "backing_fmt"
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#define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
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#define BLOCK_OPT_TABLE_SIZE "table_size"
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#define BLOCK_OPT_PREALLOC "preallocation"
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#define BLOCK_OPT_SUBFMT "subformat"
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#define BLOCK_OPT_COMPAT_LEVEL "compat"
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#define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts"
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#define BLOCK_OPT_ADAPTER_TYPE "adapter_type"
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#define BLOCK_OPT_REDUNDANCY "redundancy"
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#define BLOCK_OPT_NOCOW "nocow"
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#define BLOCK_OPT_EXTENT_SIZE_HINT "extent_size_hint"
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#define BLOCK_OPT_OBJECT_SIZE "object_size"
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#define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
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#define BLOCK_OPT_DATA_FILE "data_file"
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#define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
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#define BLOCK_OPT_COMPRESSION_TYPE "compression_type"
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#define BLOCK_OPT_EXTL2 "extended_l2"
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#define BLOCK_PROBE_BUF_SIZE 512
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enum BdrvTrackedRequestType {
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BDRV_TRACKED_READ,
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BDRV_TRACKED_WRITE,
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BDRV_TRACKED_DISCARD,
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BDRV_TRACKED_TRUNCATE,
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};
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/*
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* That is not quite good that BdrvTrackedRequest structure is public,
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* as block/io.c is very careful about incoming offset/bytes being
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* correct. Be sure to assert bdrv_check_request() succeeded after any
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* modification of BdrvTrackedRequest object out of block/io.c
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*/
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typedef struct BdrvTrackedRequest {
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BlockDriverState *bs;
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int64_t offset;
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int64_t bytes;
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enum BdrvTrackedRequestType type;
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bool serialising;
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int64_t overlap_offset;
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int64_t overlap_bytes;
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QLIST_ENTRY(BdrvTrackedRequest) list;
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Coroutine *co; /* owner, used for deadlock detection */
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CoQueue wait_queue; /* coroutines blocked on this request */
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struct BdrvTrackedRequest *waiting_for;
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} BdrvTrackedRequest;
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struct BlockDriver {
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/*
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* These fields are initialized when this object is created,
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* and are never changed afterwards.
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*/
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const char *format_name;
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int instance_size;
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/*
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* Set to true if the BlockDriver is a block filter. Block filters pass
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* certain callbacks that refer to data (see block.c) to their bs->file
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* or bs->backing (whichever one exists) if the driver doesn't implement
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* them. Drivers that do not wish to forward must implement them and return
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* -ENOTSUP.
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* Note that filters are not allowed to modify data.
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*
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* Filters generally cannot have more than a single filtered child,
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* because the data they present must at all times be the same as
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* that on their filtered child. That would be impossible to
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* achieve for multiple filtered children.
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* (And this filtered child must then be bs->file or bs->backing.)
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*/
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bool is_filter;
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/*
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* Only make sense for filter drivers, for others must be false.
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* If true, filtered child is bs->backing. Otherwise it's bs->file.
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* Two internal filters use bs->backing as filtered child and has this
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* field set to true: mirror_top and commit_top. There also two such test
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* filters in tests/unit/test-bdrv-graph-mod.c.
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*
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* Never create any more such filters!
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*
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* TODO: imagine how to deprecate this behavior and make all filters work
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* similarly using bs->file as filtered child.
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*/
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bool filtered_child_is_backing;
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/*
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* Set to true if the BlockDriver is a format driver. Format nodes
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* generally do not expect their children to be other format nodes
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* (except for backing files), and so format probing is disabled
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* on those children.
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*/
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bool is_format;
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/*
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* Set to true if the BlockDriver supports zoned children.
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*/
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bool supports_zoned_children;
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/*
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* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
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* this field set to true, except ones that are defined only by their
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* child's bs.
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* An example of the last type will be the quorum block driver.
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*/
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bool bdrv_needs_filename;
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/*
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* Set if a driver can support backing files. This also implies the
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* following semantics:
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*
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* - Return status 0 of .bdrv_co_block_status means that corresponding
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* blocks are not allocated in this layer of backing-chain
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* - For such (unallocated) blocks, read will:
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* - fill buffer with zeros if there is no backing file
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* - read from the backing file otherwise, where the block layer
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* takes care of reading zeros beyond EOF if backing file is short
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*/
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bool supports_backing;
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/*
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* Drivers setting this field must be able to work with just a plain
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* filename with '<protocol_name>:' as a prefix, and no other options.
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* Options may be extracted from the filename by implementing
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* bdrv_parse_filename.
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*/
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const char *protocol_name;
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/* List of options for creating images, terminated by name == NULL */
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QemuOptsList *create_opts;
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/* List of options for image amend */
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QemuOptsList *amend_opts;
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/*
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* If this driver supports reopening images this contains a
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* NULL-terminated list of the runtime options that can be
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* modified. If an option in this list is unspecified during
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* reopen then it _must_ be reset to its default value or return
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* an error.
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*/
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const char *const *mutable_opts;
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/*
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* Pointer to a NULL-terminated array of names of strong options
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* that can be specified for bdrv_open(). A strong option is one
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* that changes the data of a BDS.
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* If this pointer is NULL, the array is considered empty.
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* "filename" and "driver" are always considered strong.
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*/
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const char *const *strong_runtime_opts;
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/*
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* Global state (GS) API. These functions run under the BQL.
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*
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* See include/block/block-global-state.h for more information about
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* the GS API.
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*/
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/*
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* This function is invoked under BQL before .bdrv_co_amend()
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* (which in contrast does not necessarily run under the BQL)
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* to allow driver-specific initialization code that requires
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* the BQL, like setting up specific permission flags.
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*/
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int GRAPH_RDLOCK_PTR (*bdrv_amend_pre_run)(
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BlockDriverState *bs, Error **errp);
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/*
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* This function is invoked under BQL after .bdrv_co_amend()
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* to allow cleaning up what was done in .bdrv_amend_pre_run().
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*/
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void GRAPH_RDLOCK_PTR (*bdrv_amend_clean)(BlockDriverState *bs);
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/*
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* Return true if @to_replace can be replaced by a BDS with the
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* same data as @bs without it affecting @bs's behavior (that is,
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* without it being visible to @bs's parents).
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*/
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bool GRAPH_RDLOCK_PTR (*bdrv_recurse_can_replace)(
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BlockDriverState *bs, BlockDriverState *to_replace);
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int (*bdrv_probe_device)(const char *filename);
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/*
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* Any driver implementing this callback is expected to be able to handle
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* NULL file names in its .bdrv_open() implementation.
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*/
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void (*bdrv_parse_filename)(const char *filename, QDict *options,
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Error **errp);
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/* For handling image reopen for split or non-split files. */
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int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state,
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BlockReopenQueue *queue, Error **errp);
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void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state);
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void (*bdrv_reopen_commit_post)(BDRVReopenState *reopen_state);
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void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state);
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void (*bdrv_join_options)(QDict *options, QDict *old_options);
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int GRAPH_UNLOCKED_PTR (*bdrv_open)(
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BlockDriverState *bs, QDict *options, int flags, Error **errp);
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/* Protocol drivers should implement this instead of bdrv_open */
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int GRAPH_UNLOCKED_PTR (*bdrv_file_open)(
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BlockDriverState *bs, QDict *options, int flags, Error **errp);
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void (*bdrv_close)(BlockDriverState *bs);
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int coroutine_fn GRAPH_UNLOCKED_PTR (*bdrv_co_create)(
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BlockdevCreateOptions *opts, Error **errp);
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int coroutine_fn GRAPH_UNLOCKED_PTR (*bdrv_co_create_opts)(
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BlockDriver *drv, const char *filename, QemuOpts *opts, Error **errp);
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int (*bdrv_amend_options)(BlockDriverState *bs,
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QemuOpts *opts,
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BlockDriverAmendStatusCB *status_cb,
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void *cb_opaque,
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bool force,
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Error **errp);
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int (*bdrv_make_empty)(BlockDriverState *bs);
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/*
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* Refreshes the bs->exact_filename field. If that is impossible,
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* bs->exact_filename has to be left empty.
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*/
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void (*bdrv_refresh_filename)(BlockDriverState *bs);
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/*
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* Gathers the open options for all children into @target.
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* A simple format driver (without backing file support) might
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* implement this function like this:
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*
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* QINCREF(bs->file->bs->full_open_options);
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* qdict_put(target, "file", bs->file->bs->full_open_options);
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*
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* If not specified, the generic implementation will simply put
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* all children's options under their respective name.
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*
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* @backing_overridden is true when bs->backing seems not to be
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* the child that would result from opening bs->backing_file.
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* Therefore, if it is true, the backing child's options should be
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* gathered; otherwise, there is no need since the backing child
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* is the one implied by the image header.
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*
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* Note that ideally this function would not be needed. Every
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* block driver which implements it is probably doing something
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* shady regarding its runtime option structure.
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*/
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void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target,
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bool backing_overridden);
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/*
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* Returns an allocated string which is the directory name of this BDS: It
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* will be used to make relative filenames absolute by prepending this
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* function's return value to them.
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*/
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char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp);
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/*
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* This informs the driver that we are no longer interested in the result
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* of in-flight requests, so don't waste the time if possible.
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*
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* One example usage is to avoid waiting for an nbd target node reconnect
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* timeout during job-cancel with force=true.
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*/
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void (*bdrv_cancel_in_flight)(BlockDriverState *bs);
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int (*bdrv_inactivate)(BlockDriverState *bs);
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int (*bdrv_snapshot_create)(BlockDriverState *bs,
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QEMUSnapshotInfo *sn_info);
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int (*bdrv_snapshot_goto)(BlockDriverState *bs,
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const char *snapshot_id);
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int (*bdrv_snapshot_delete)(BlockDriverState *bs,
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const char *snapshot_id,
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const char *name,
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Error **errp);
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int (*bdrv_snapshot_list)(BlockDriverState *bs,
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QEMUSnapshotInfo **psn_info);
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int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
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const char *snapshot_id,
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const char *name,
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Error **errp);
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int (*bdrv_change_backing_file)(BlockDriverState *bs,
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const char *backing_file, const char *backing_fmt);
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/* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
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int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event,
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const char *tag);
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int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs,
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const char *tag);
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int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag);
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bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag);
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void GRAPH_RDLOCK_PTR (*bdrv_refresh_limits)(
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BlockDriverState *bs, Error **errp);
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/*
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* Returns 1 if newly created images are guaranteed to contain only
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* zeros, 0 otherwise.
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*/
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int (*bdrv_has_zero_init)(BlockDriverState *bs);
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/*
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* Remove fd handlers, timers, and other event loop callbacks so the event
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* loop is no longer in use. Called with no in-flight requests and in
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* depth-first traversal order with parents before child nodes.
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*/
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void (*bdrv_detach_aio_context)(BlockDriverState *bs);
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/*
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* Add fd handlers, timers, and other event loop callbacks so I/O requests
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* can be processed again. Called with no in-flight requests and in
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* depth-first traversal order with child nodes before parent nodes.
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*/
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void (*bdrv_attach_aio_context)(BlockDriverState *bs,
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AioContext *new_context);
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/**
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* bdrv_drain_begin is called if implemented in the beginning of a
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* drain operation to drain and stop any internal sources of requests in
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* the driver.
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* bdrv_drain_end is called if implemented at the end of the drain.
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*
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* They should be used by the driver to e.g. manage scheduled I/O
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* requests, or toggle an internal state. After the end of the drain new
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* requests will continue normally.
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*
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* Implementations of both functions must not call aio_poll().
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*/
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void (*bdrv_drain_begin)(BlockDriverState *bs);
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void (*bdrv_drain_end)(BlockDriverState *bs);
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/**
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* Try to get @bs's logical and physical block size.
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* On success, store them in @bsz and return zero.
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* On failure, return negative errno.
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*/
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int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz);
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/**
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* Try to get @bs's geometry (cyls, heads, sectors)
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* On success, store them in @geo and return 0.
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* On failure return -errno.
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* Only drivers that want to override guest geometry implement this
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* callback; see hd_geometry_guess().
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*/
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int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
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void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child,
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Error **errp);
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void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child,
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Error **errp);
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/**
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* Informs the block driver that a permission change is intended. The
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* driver checks whether the change is permissible and may take other
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* preparations for the change (e.g. get file system locks). This operation
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* is always followed either by a call to either .bdrv_set_perm or
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* .bdrv_abort_perm_update.
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*
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* Checks whether the requested set of cumulative permissions in @perm
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* can be granted for accessing @bs and whether no other users are using
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* permissions other than those given in @shared (both arguments take
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* BLK_PERM_* bitmasks).
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*
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* If both conditions are met, 0 is returned. Otherwise, -errno is returned
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* and errp is set to an error describing the conflict.
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*/
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int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm,
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uint64_t shared, Error **errp);
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/**
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* Called to inform the driver that the set of cumulative set of used
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* permissions for @bs has changed to @perm, and the set of sharable
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* permission to @shared. The driver can use this to propagate changes to
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* its children (i.e. request permissions only if a parent actually needs
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* them).
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*
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* This function is only invoked after bdrv_check_perm(), so block drivers
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* may rely on preparations made in their .bdrv_check_perm implementation.
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*/
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void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared);
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/*
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* Called to inform the driver that after a previous bdrv_check_perm()
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* call, the permission update is not performed and any preparations made
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* for it (e.g. taken file locks) need to be undone.
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*
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* This function can be called even for nodes that never saw a
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* bdrv_check_perm() call. It is a no-op then.
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*/
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void (*bdrv_abort_perm_update)(BlockDriverState *bs);
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/**
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* Returns in @nperm and @nshared the permissions that the driver for @bs
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* needs on its child @c, based on the cumulative permissions requested by
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* the parents in @parent_perm and @parent_shared.
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*
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* If @c is NULL, return the permissions for attaching a new child for the
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* given @child_class and @role.
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*
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* If @reopen_queue is non-NULL, don't return the currently needed
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* permissions, but those that will be needed after applying the
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* @reopen_queue.
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*/
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void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c,
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BdrvChildRole role,
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BlockReopenQueue *reopen_queue,
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uint64_t parent_perm, uint64_t parent_shared,
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uint64_t *nperm, uint64_t *nshared);
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/**
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* Register/unregister a buffer for I/O. For example, when the driver is
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* interested to know the memory areas that will later be used in iovs, so
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* that it can do IOMMU mapping with VFIO etc., in order to get better
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* performance. In the case of VFIO drivers, this callback is used to do
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* DMA mapping for hot buffers.
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*
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* Returns: true on success, false on failure
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*/
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bool GRAPH_RDLOCK_PTR (*bdrv_register_buf)(
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BlockDriverState *bs, void *host, size_t size, Error **errp);
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void GRAPH_RDLOCK_PTR (*bdrv_unregister_buf)(
|
|
BlockDriverState *bs, void *host, size_t size);
|
|
|
|
/*
|
|
* This field is modified only under the BQL, and is part of
|
|
* the global state.
|
|
*/
|
|
QLIST_ENTRY(BlockDriver) list;
|
|
|
|
/*
|
|
* I/O API functions. These functions are thread-safe.
|
|
*
|
|
* See include/block/block-io.h for more information about
|
|
* the I/O API.
|
|
*/
|
|
|
|
int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_amend)(
|
|
BlockDriverState *bs, BlockdevAmendOptions *opts, bool force,
|
|
Error **errp);
|
|
|
|
/* aio */
|
|
BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_preadv)(BlockDriverState *bs,
|
|
int64_t offset, int64_t bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque);
|
|
|
|
BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_pwritev)(BlockDriverState *bs,
|
|
int64_t offset, int64_t bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque);
|
|
|
|
BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_flush)(
|
|
BlockDriverState *bs, BlockCompletionFunc *cb, void *opaque);
|
|
|
|
BlockAIOCB * GRAPH_RDLOCK_PTR (*bdrv_aio_pdiscard)(
|
|
BlockDriverState *bs, int64_t offset, int bytes,
|
|
BlockCompletionFunc *cb, void *opaque);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_readv)(BlockDriverState *bs,
|
|
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
|
|
|
|
/**
|
|
* @offset: position in bytes to read at
|
|
* @bytes: number of bytes to read
|
|
* @qiov: the buffers to fill with read data
|
|
* @flags: currently unused, always 0
|
|
*
|
|
* @offset and @bytes will be a multiple of 'request_alignment',
|
|
* but the length of individual @qiov elements does not have to
|
|
* be a multiple.
|
|
*
|
|
* @bytes will always equal the total size of @qiov, and will be
|
|
* no larger than 'max_transfer'.
|
|
*
|
|
* The buffer in @qiov may point directly to guest memory.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv)(BlockDriverState *bs,
|
|
int64_t offset, int64_t bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv_part)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes,
|
|
QEMUIOVector *qiov, size_t qiov_offset,
|
|
BdrvRequestFlags flags);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_writev)(BlockDriverState *bs,
|
|
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
|
|
int flags);
|
|
/**
|
|
* @offset: position in bytes to write at
|
|
* @bytes: number of bytes to write
|
|
* @qiov: the buffers containing data to write
|
|
* @flags: zero or more bits allowed by 'supported_write_flags'
|
|
*
|
|
* @offset and @bytes will be a multiple of 'request_alignment',
|
|
* but the length of individual @qiov elements does not have to
|
|
* be a multiple.
|
|
*
|
|
* @bytes will always equal the total size of @qiov, and will be
|
|
* no larger than 'max_transfer'.
|
|
*
|
|
* The buffer in @qiov may point directly to guest memory.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags);
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev_part)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov,
|
|
size_t qiov_offset, BdrvRequestFlags flags);
|
|
|
|
/*
|
|
* Efficiently zero a region of the disk image. Typically an image format
|
|
* would use a compact metadata representation to implement this. This
|
|
* function pointer may be NULL or return -ENOSUP and .bdrv_co_writev()
|
|
* will be called instead.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwrite_zeroes)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes,
|
|
BdrvRequestFlags flags);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pdiscard)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes);
|
|
|
|
/*
|
|
* Map [offset, offset + nbytes) range onto a child of @bs to copy from,
|
|
* and invoke bdrv_co_copy_range_from(child, ...), or invoke
|
|
* bdrv_co_copy_range_to() if @bs is the leaf child to copy data from.
|
|
*
|
|
* See the comment of bdrv_co_copy_range for the parameter and return value
|
|
* semantics.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_copy_range_from)(
|
|
BlockDriverState *bs, BdrvChild *src, int64_t offset,
|
|
BdrvChild *dst, int64_t dst_offset, int64_t bytes,
|
|
BdrvRequestFlags read_flags, BdrvRequestFlags write_flags);
|
|
|
|
/*
|
|
* Map [offset, offset + nbytes) range onto a child of bs to copy data to,
|
|
* and invoke bdrv_co_copy_range_to(child, src, ...), or perform the copy
|
|
* operation if @bs is the leaf and @src has the same BlockDriver. Return
|
|
* -ENOTSUP if @bs is the leaf but @src has a different BlockDriver.
|
|
*
|
|
* See the comment of bdrv_co_copy_range for the parameter and return value
|
|
* semantics.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_copy_range_to)(
|
|
BlockDriverState *bs, BdrvChild *src, int64_t src_offset,
|
|
BdrvChild *dst, int64_t dst_offset, int64_t bytes,
|
|
BdrvRequestFlags read_flags, BdrvRequestFlags write_flags);
|
|
|
|
/*
|
|
* Building block for bdrv_block_status[_above] and
|
|
* bdrv_is_allocated[_above]. The driver should answer only
|
|
* according to the current layer, and should only need to set
|
|
* BDRV_BLOCK_DATA, BDRV_BLOCK_ZERO, BDRV_BLOCK_OFFSET_VALID,
|
|
* and/or BDRV_BLOCK_RAW; if the current layer defers to a backing
|
|
* layer, the result should be 0 (and not BDRV_BLOCK_ZERO). See
|
|
* block.h for the overall meaning of the bits. As a hint, the
|
|
* flag want_zero is true if the caller cares more about precise
|
|
* mappings (favor accurate _OFFSET_VALID/_ZERO) or false for
|
|
* overall allocation (favor larger *pnum, perhaps by reporting
|
|
* _DATA instead of _ZERO). The block layer guarantees input
|
|
* clamped to bdrv_getlength() and aligned to request_alignment,
|
|
* as well as non-NULL pnum, map, and file; in turn, the driver
|
|
* must return an error or set pnum to an aligned non-zero value.
|
|
*
|
|
* Note that @bytes is just a hint on how big of a region the
|
|
* caller wants to inspect. It is not a limit on *pnum.
|
|
* Implementations are free to return larger values of *pnum if
|
|
* doing so does not incur a performance penalty.
|
|
*
|
|
* block/io.c's bdrv_co_block_status() will utilize an unclamped
|
|
* *pnum value for the block-status cache on protocol nodes, prior
|
|
* to clamping *pnum for return to its caller.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_block_status)(
|
|
BlockDriverState *bs,
|
|
bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
|
|
int64_t *map, BlockDriverState **file);
|
|
|
|
/*
|
|
* Snapshot-access API.
|
|
*
|
|
* Block-driver may provide snapshot-access API: special functions to access
|
|
* some internal "snapshot". The functions are similar with normal
|
|
* read/block_status/discard handler, but don't have any specific handling
|
|
* in generic block-layer: no serializing, no alignment, no tracked
|
|
* requests. So, block-driver that realizes these APIs is fully responsible
|
|
* for synchronization between snapshot-access API and normal IO requests.
|
|
*
|
|
* TODO: To be able to support qcow2's internal snapshots, this API will
|
|
* need to be extended to:
|
|
* - be able to select a specific snapshot
|
|
* - receive the snapshot's actual length (which may differ from bs's
|
|
* length)
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv_snapshot)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes,
|
|
QEMUIOVector *qiov, size_t qiov_offset);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_snapshot_block_status)(
|
|
BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes,
|
|
int64_t *pnum, int64_t *map, BlockDriverState **file);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pdiscard_snapshot)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes);
|
|
|
|
/*
|
|
* Invalidate any cached meta-data.
|
|
*/
|
|
void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_invalidate_cache)(
|
|
BlockDriverState *bs, Error **errp);
|
|
|
|
/*
|
|
* Flushes all data for all layers by calling bdrv_co_flush for underlying
|
|
* layers, if needed. This function is needed for deterministic
|
|
* synchronization of the flush finishing callback.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_flush)(BlockDriverState *bs);
|
|
|
|
/* Delete a created file. */
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_delete_file)(
|
|
BlockDriverState *bs, Error **errp);
|
|
|
|
/*
|
|
* Flushes all data that was already written to the OS all the way down to
|
|
* the disk (for example file-posix.c calls fsync()).
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_flush_to_disk)(
|
|
BlockDriverState *bs);
|
|
|
|
/*
|
|
* Flushes all internal caches to the OS. The data may still sit in a
|
|
* writeback cache of the host OS, but it will survive a crash of the qemu
|
|
* process.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_flush_to_os)(
|
|
BlockDriverState *bs);
|
|
|
|
/*
|
|
* Truncate @bs to @offset bytes using the given @prealloc mode
|
|
* when growing. Modes other than PREALLOC_MODE_OFF should be
|
|
* rejected when shrinking @bs.
|
|
*
|
|
* If @exact is true, @bs must be resized to exactly @offset.
|
|
* Otherwise, it is sufficient for @bs (if it is a host block
|
|
* device and thus there is no way to resize it) to be at least
|
|
* @offset bytes in length.
|
|
*
|
|
* If @exact is true and this function fails but would succeed
|
|
* with @exact = false, it should return -ENOTSUP.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_truncate)(
|
|
BlockDriverState *bs, int64_t offset, bool exact,
|
|
PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
|
|
|
|
int64_t coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_getlength)(
|
|
BlockDriverState *bs);
|
|
|
|
int64_t coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_get_allocated_file_size)(
|
|
BlockDriverState *bs);
|
|
|
|
BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs,
|
|
Error **errp);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev_compressed)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes,
|
|
QEMUIOVector *qiov);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pwritev_compressed_part)(
|
|
BlockDriverState *bs, int64_t offset, int64_t bytes,
|
|
QEMUIOVector *qiov, size_t qiov_offset);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_get_info)(
|
|
BlockDriverState *bs, BlockDriverInfo *bdi);
|
|
|
|
ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs,
|
|
Error **errp);
|
|
BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_save_vmstate)(
|
|
BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_load_vmstate)(
|
|
BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
|
|
|
|
int coroutine_fn (*bdrv_co_zone_report)(BlockDriverState *bs,
|
|
int64_t offset, unsigned int *nr_zones,
|
|
BlockZoneDescriptor *zones);
|
|
int coroutine_fn (*bdrv_co_zone_mgmt)(BlockDriverState *bs, BlockZoneOp op,
|
|
int64_t offset, int64_t len);
|
|
int coroutine_fn (*bdrv_co_zone_append)(BlockDriverState *bs,
|
|
int64_t *offset, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags);
|
|
|
|
/* removable device specific */
|
|
bool coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_is_inserted)(
|
|
BlockDriverState *bs);
|
|
void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_eject)(
|
|
BlockDriverState *bs, bool eject_flag);
|
|
void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_lock_medium)(
|
|
BlockDriverState *bs, bool locked);
|
|
|
|
/* to control generic scsi devices */
|
|
BlockAIOCB *coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_aio_ioctl)(
|
|
BlockDriverState *bs, unsigned long int req, void *buf,
|
|
BlockCompletionFunc *cb, void *opaque);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_ioctl)(
|
|
BlockDriverState *bs, unsigned long int req, void *buf);
|
|
|
|
/*
|
|
* Returns 0 for completed check, -errno for internal errors.
|
|
* The check results are stored in result.
|
|
*/
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)(
|
|
BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix);
|
|
|
|
void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_debug_event)(
|
|
BlockDriverState *bs, BlkdebugEvent event);
|
|
|
|
bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs);
|
|
|
|
bool coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_can_store_new_dirty_bitmap)(
|
|
BlockDriverState *bs, const char *name, uint32_t granularity,
|
|
Error **errp);
|
|
|
|
int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_remove_persistent_dirty_bitmap)(
|
|
BlockDriverState *bs, const char *name, Error **errp);
|
|
};
|
|
|
|
static inline bool TSA_NO_TSA block_driver_can_compress(BlockDriver *drv)
|
|
{
|
|
return drv->bdrv_co_pwritev_compressed ||
|
|
drv->bdrv_co_pwritev_compressed_part;
|
|
}
|
|
|
|
typedef struct BlockLimits {
|
|
/*
|
|
* Alignment requirement, in bytes, for offset/length of I/O
|
|
* requests. Must be a power of 2 less than INT_MAX; defaults to
|
|
* 1 for drivers with modern byte interfaces, and to 512
|
|
* otherwise.
|
|
*/
|
|
uint32_t request_alignment;
|
|
|
|
/*
|
|
* Maximum number of bytes that can be discarded at once. Must be multiple
|
|
* of pdiscard_alignment, but need not be power of 2. May be 0 if no
|
|
* inherent 64-bit limit.
|
|
*/
|
|
int64_t max_pdiscard;
|
|
|
|
/*
|
|
* Optimal alignment for discard requests in bytes. A power of 2
|
|
* is best but not mandatory. Must be a multiple of
|
|
* bl.request_alignment, and must be less than max_pdiscard if
|
|
* that is set. May be 0 if bl.request_alignment is good enough
|
|
*/
|
|
uint32_t pdiscard_alignment;
|
|
|
|
/*
|
|
* Maximum number of bytes that can zeroized at once. Must be multiple of
|
|
* pwrite_zeroes_alignment. 0 means no limit.
|
|
*/
|
|
int64_t max_pwrite_zeroes;
|
|
|
|
/*
|
|
* Optimal alignment for write zeroes requests in bytes. A power
|
|
* of 2 is best but not mandatory. Must be a multiple of
|
|
* bl.request_alignment, and must be less than max_pwrite_zeroes
|
|
* if that is set. May be 0 if bl.request_alignment is good
|
|
* enough
|
|
*/
|
|
uint32_t pwrite_zeroes_alignment;
|
|
|
|
/*
|
|
* Optimal transfer length in bytes. A power of 2 is best but not
|
|
* mandatory. Must be a multiple of bl.request_alignment, or 0 if
|
|
* no preferred size
|
|
*/
|
|
uint32_t opt_transfer;
|
|
|
|
/*
|
|
* Maximal transfer length in bytes. Need not be power of 2, but
|
|
* must be multiple of opt_transfer and bl.request_alignment, or 0
|
|
* for no 32-bit limit. For now, anything larger than INT_MAX is
|
|
* clamped down.
|
|
*/
|
|
uint32_t max_transfer;
|
|
|
|
/*
|
|
* Maximal hardware transfer length in bytes. Applies whenever
|
|
* transfers to the device bypass the kernel I/O scheduler, for
|
|
* example with SG_IO. If larger than max_transfer or if zero,
|
|
* blk_get_max_hw_transfer will fall back to max_transfer.
|
|
*/
|
|
uint64_t max_hw_transfer;
|
|
|
|
/*
|
|
* Maximal number of scatter/gather elements allowed by the hardware.
|
|
* Applies whenever transfers to the device bypass the kernel I/O
|
|
* scheduler, for example with SG_IO. If larger than max_iov
|
|
* or if zero, blk_get_max_hw_iov will fall back to max_iov.
|
|
*/
|
|
int max_hw_iov;
|
|
|
|
|
|
/* memory alignment, in bytes so that no bounce buffer is needed */
|
|
size_t min_mem_alignment;
|
|
|
|
/* memory alignment, in bytes, for bounce buffer */
|
|
size_t opt_mem_alignment;
|
|
|
|
/* maximum number of iovec elements */
|
|
int max_iov;
|
|
|
|
/*
|
|
* true if the length of the underlying file can change, and QEMU
|
|
* is expected to adjust automatically. Mostly for CD-ROM drives,
|
|
* whose length is zero when the tray is empty (they don't need
|
|
* an explicit monitor command to load the disk inside the guest).
|
|
*/
|
|
bool has_variable_length;
|
|
|
|
/* device zone model */
|
|
BlockZoneModel zoned;
|
|
|
|
/* zone size expressed in bytes */
|
|
uint32_t zone_size;
|
|
|
|
/* total number of zones */
|
|
uint32_t nr_zones;
|
|
|
|
/* maximum sectors of a zone append write operation */
|
|
uint32_t max_append_sectors;
|
|
|
|
/* maximum number of open zones */
|
|
uint32_t max_open_zones;
|
|
|
|
/* maximum number of active zones */
|
|
uint32_t max_active_zones;
|
|
|
|
uint32_t write_granularity;
|
|
} BlockLimits;
|
|
|
|
typedef struct BdrvOpBlocker BdrvOpBlocker;
|
|
|
|
typedef struct BdrvAioNotifier {
|
|
void (*attached_aio_context)(AioContext *new_context, void *opaque);
|
|
void (*detach_aio_context)(void *opaque);
|
|
|
|
void *opaque;
|
|
bool deleted;
|
|
|
|
QLIST_ENTRY(BdrvAioNotifier) list;
|
|
} BdrvAioNotifier;
|
|
|
|
struct BdrvChildClass {
|
|
/*
|
|
* If true, bdrv_replace_node() doesn't change the node this BdrvChild
|
|
* points to.
|
|
*/
|
|
bool stay_at_node;
|
|
|
|
/*
|
|
* If true, the parent is a BlockDriverState and bdrv_next_all_states()
|
|
* will return it. This information is used for drain_all, where every node
|
|
* will be drained separately, so the drain only needs to be propagated to
|
|
* non-BDS parents.
|
|
*/
|
|
bool parent_is_bds;
|
|
|
|
/*
|
|
* Global state (GS) API. These functions run under the BQL.
|
|
*
|
|
* See include/block/block-global-state.h for more information about
|
|
* the GS API.
|
|
*/
|
|
void (*inherit_options)(BdrvChildRole role, bool parent_is_format,
|
|
int *child_flags, QDict *child_options,
|
|
int parent_flags, QDict *parent_options);
|
|
void (*change_media)(BdrvChild *child, bool load);
|
|
|
|
/*
|
|
* Returns a malloced string that describes the parent of the child for a
|
|
* human reader. This could be a node-name, BlockBackend name, qdev ID or
|
|
* QOM path of the device owning the BlockBackend, job type and ID etc. The
|
|
* caller is responsible for freeing the memory.
|
|
*/
|
|
char *(*get_parent_desc)(BdrvChild *child);
|
|
|
|
/*
|
|
* Notifies the parent that the child has been activated/inactivated (e.g.
|
|
* when migration is completing) and it can start/stop requesting
|
|
* permissions and doing I/O on it.
|
|
*/
|
|
void (*activate)(BdrvChild *child, Error **errp);
|
|
int (*inactivate)(BdrvChild *child);
|
|
|
|
void GRAPH_WRLOCK_PTR (*attach)(BdrvChild *child);
|
|
void GRAPH_WRLOCK_PTR (*detach)(BdrvChild *child);
|
|
|
|
/*
|
|
* If this pair of functions is implemented, the parent doesn't issue new
|
|
* requests after returning from .drained_begin() until .drained_end() is
|
|
* called.
|
|
*
|
|
* These functions must not change the graph (and therefore also must not
|
|
* call aio_poll(), which could change the graph indirectly).
|
|
*
|
|
* Note that this can be nested. If drained_begin() was called twice, new
|
|
* I/O is allowed only after drained_end() was called twice, too.
|
|
*/
|
|
void (*drained_begin)(BdrvChild *child);
|
|
void (*drained_end)(BdrvChild *child);
|
|
|
|
/*
|
|
* Returns whether the parent has pending requests for the child. This
|
|
* callback is polled after .drained_begin() has been called until all
|
|
* activity on the child has stopped.
|
|
*/
|
|
bool (*drained_poll)(BdrvChild *child);
|
|
|
|
/*
|
|
* Notifies the parent that the filename of its child has changed (e.g.
|
|
* because the direct child was removed from the backing chain), so that it
|
|
* can update its reference.
|
|
*/
|
|
int (*update_filename)(BdrvChild *child, BlockDriverState *new_base,
|
|
const char *filename, Error **errp);
|
|
|
|
bool (*change_aio_ctx)(BdrvChild *child, AioContext *ctx,
|
|
GHashTable *visited, Transaction *tran,
|
|
Error **errp);
|
|
|
|
/*
|
|
* I/O API functions. These functions are thread-safe.
|
|
*
|
|
* See include/block/block-io.h for more information about
|
|
* the I/O API.
|
|
*/
|
|
|
|
void (*resize)(BdrvChild *child);
|
|
|
|
/*
|
|
* Returns a name that is supposedly more useful for human users than the
|
|
* node name for identifying the node in question (in particular, a BB
|
|
* name), or NULL if the parent can't provide a better name.
|
|
*/
|
|
const char *(*get_name)(BdrvChild *child);
|
|
|
|
AioContext *(*get_parent_aio_context)(BdrvChild *child);
|
|
};
|
|
|
|
extern const BdrvChildClass child_of_bds;
|
|
|
|
struct BdrvChild {
|
|
BlockDriverState *bs;
|
|
char *name;
|
|
const BdrvChildClass *klass;
|
|
BdrvChildRole role;
|
|
void *opaque;
|
|
|
|
/**
|
|
* Granted permissions for operating on this BdrvChild (BLK_PERM_* bitmask)
|
|
*/
|
|
uint64_t perm;
|
|
|
|
/**
|
|
* Permissions that can still be granted to other users of @bs while this
|
|
* BdrvChild is still attached to it. (BLK_PERM_* bitmask)
|
|
*/
|
|
uint64_t shared_perm;
|
|
|
|
/*
|
|
* This link is frozen: the child can neither be replaced nor
|
|
* detached from the parent.
|
|
*/
|
|
bool frozen;
|
|
|
|
/*
|
|
* True if the parent of this child has been drained by this BdrvChild
|
|
* (through klass->drained_*).
|
|
*
|
|
* It is generally true if bs->quiesce_counter > 0. It may differ while the
|
|
* child is entering or leaving a drained section.
|
|
*/
|
|
bool quiesced_parent;
|
|
|
|
QLIST_ENTRY(BdrvChild) next;
|
|
QLIST_ENTRY(BdrvChild) next_parent;
|
|
};
|
|
|
|
/*
|
|
* Allows bdrv_co_block_status() to cache one data region for a
|
|
* protocol node.
|
|
*
|
|
* @valid: Whether the cache is valid (should be accessed with atomic
|
|
* functions so this can be reset by RCU readers)
|
|
* @data_start: Offset where we know (or strongly assume) is data
|
|
* @data_end: Offset where the data region ends (which is not necessarily
|
|
* the start of a zeroed region)
|
|
*/
|
|
typedef struct BdrvBlockStatusCache {
|
|
struct rcu_head rcu;
|
|
|
|
bool valid;
|
|
int64_t data_start;
|
|
int64_t data_end;
|
|
} BdrvBlockStatusCache;
|
|
|
|
struct BlockDriverState {
|
|
/*
|
|
* Protected by big QEMU lock or read-only after opening. No special
|
|
* locking needed during I/O...
|
|
*/
|
|
int open_flags; /* flags used to open the file, re-used for re-open */
|
|
bool encrypted; /* if true, the media is encrypted */
|
|
bool sg; /* if true, the device is a /dev/sg* */
|
|
bool probed; /* if true, format was probed rather than specified */
|
|
bool force_share; /* if true, always allow all shared permissions */
|
|
bool implicit; /* if true, this filter node was automatically inserted */
|
|
|
|
BlockDriver *drv; /* NULL means no media */
|
|
void *opaque;
|
|
|
|
AioContext *aio_context; /* event loop used for fd handlers, timers, etc */
|
|
/*
|
|
* long-running tasks intended to always use the same AioContext as this
|
|
* BDS may register themselves in this list to be notified of changes
|
|
* regarding this BDS's context
|
|
*/
|
|
QLIST_HEAD(, BdrvAioNotifier) aio_notifiers;
|
|
bool walking_aio_notifiers; /* to make removal during iteration safe */
|
|
|
|
char filename[PATH_MAX];
|
|
/*
|
|
* If not empty, this image is a diff in relation to backing_file.
|
|
* Note that this is the name given in the image header and
|
|
* therefore may or may not be equal to .backing->bs->filename.
|
|
* If this field contains a relative path, it is to be resolved
|
|
* relatively to the overlay's location.
|
|
*/
|
|
char backing_file[PATH_MAX];
|
|
/*
|
|
* The backing filename indicated by the image header. Contrary
|
|
* to backing_file, if we ever open this file, auto_backing_file
|
|
* is replaced by the resulting BDS's filename (i.e. after a
|
|
* bdrv_refresh_filename() run).
|
|
*/
|
|
char auto_backing_file[PATH_MAX];
|
|
char backing_format[16]; /* if non-zero and backing_file exists */
|
|
|
|
QDict *full_open_options;
|
|
char exact_filename[PATH_MAX];
|
|
|
|
/* I/O Limits */
|
|
BlockLimits bl;
|
|
|
|
/*
|
|
* Flags honored during pread
|
|
*/
|
|
BdrvRequestFlags supported_read_flags;
|
|
/*
|
|
* Flags honored during pwrite (so far: BDRV_REQ_FUA,
|
|
* BDRV_REQ_WRITE_UNCHANGED).
|
|
* If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those
|
|
* writes will be issued as normal writes without the flag set.
|
|
* This is important to note for drivers that do not explicitly
|
|
* request a WRITE permission for their children and instead take
|
|
* the same permissions as their parent did (this is commonly what
|
|
* block filters do). Such drivers have to be aware that the
|
|
* parent may have taken a WRITE_UNCHANGED permission only and is
|
|
* issuing such requests. Drivers either must make sure that
|
|
* these requests do not result in plain WRITE accesses (usually
|
|
* by supporting BDRV_REQ_WRITE_UNCHANGED, and then forwarding
|
|
* every incoming write request as-is, including potentially that
|
|
* flag), or they have to explicitly take the WRITE permission for
|
|
* their children.
|
|
*/
|
|
BdrvRequestFlags supported_write_flags;
|
|
/*
|
|
* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
|
|
* BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED)
|
|
*/
|
|
BdrvRequestFlags supported_zero_flags;
|
|
/*
|
|
* Flags honoured during truncate (so far: BDRV_REQ_ZERO_WRITE).
|
|
*
|
|
* If BDRV_REQ_ZERO_WRITE is given, the truncate operation must make sure
|
|
* that any added space reads as all zeros. If this can't be guaranteed,
|
|
* the operation must fail.
|
|
*/
|
|
BdrvRequestFlags supported_truncate_flags;
|
|
|
|
/* the following member gives a name to every node on the bs graph. */
|
|
char node_name[32];
|
|
/* element of the list of named nodes building the graph */
|
|
QTAILQ_ENTRY(BlockDriverState) node_list;
|
|
/* element of the list of all BlockDriverStates (all_bdrv_states) */
|
|
QTAILQ_ENTRY(BlockDriverState) bs_list;
|
|
/* element of the list of monitor-owned BDS */
|
|
QTAILQ_ENTRY(BlockDriverState) monitor_list;
|
|
int refcnt;
|
|
|
|
/* operation blockers. Protected by BQL. */
|
|
QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
|
|
|
|
/*
|
|
* The node that this node inherited default options from (and a reopen on
|
|
* which can affect this node by changing these defaults). This is always a
|
|
* parent node of this node.
|
|
*/
|
|
BlockDriverState *inherits_from;
|
|
|
|
/*
|
|
* @backing and @file are some of @children or NULL. All these three fields
|
|
* (@file, @backing and @children) are modified only in
|
|
* bdrv_child_cb_attach() and bdrv_child_cb_detach().
|
|
*
|
|
* See also comment in include/block/block.h, to learn how backing and file
|
|
* are connected with BdrvChildRole.
|
|
*/
|
|
QLIST_HEAD(, BdrvChild) children;
|
|
BdrvChild *backing;
|
|
BdrvChild *file;
|
|
|
|
QLIST_HEAD(, BdrvChild) parents;
|
|
|
|
QDict *options;
|
|
QDict *explicit_options;
|
|
BlockdevDetectZeroesOptions detect_zeroes;
|
|
|
|
/* The error object in use for blocking operations on backing_hd */
|
|
Error *backing_blocker;
|
|
|
|
/* Protected by AioContext lock */
|
|
|
|
/*
|
|
* If we are reading a disk image, give its size in sectors.
|
|
* Generally read-only; it is written to by load_snapshot and
|
|
* save_snaphost, but the block layer is quiescent during those.
|
|
*/
|
|
int64_t total_sectors;
|
|
|
|
/* threshold limit for writes, in bytes. "High water mark". */
|
|
uint64_t write_threshold_offset;
|
|
|
|
/*
|
|
* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex.
|
|
* Reading from the list can be done with either the BQL or the
|
|
* dirty_bitmap_mutex. Modifying a bitmap only requires
|
|
* dirty_bitmap_mutex.
|
|
*/
|
|
QemuMutex dirty_bitmap_mutex;
|
|
QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
|
|
|
|
/* Offset after the highest byte written to */
|
|
Stat64 wr_highest_offset;
|
|
|
|
/*
|
|
* If true, copy read backing sectors into image. Can be >1 if more
|
|
* than one client has requested copy-on-read. Accessed with atomic
|
|
* ops.
|
|
*/
|
|
int copy_on_read;
|
|
|
|
/*
|
|
* number of in-flight requests; overall and serialising.
|
|
* Accessed with atomic ops.
|
|
*/
|
|
unsigned int in_flight;
|
|
unsigned int serialising_in_flight;
|
|
|
|
/* do we need to tell the quest if we have a volatile write cache? */
|
|
int enable_write_cache;
|
|
|
|
/* Accessed with atomic ops. */
|
|
int quiesce_counter;
|
|
|
|
unsigned int write_gen; /* Current data generation */
|
|
|
|
/* Protected by reqs_lock. */
|
|
CoMutex reqs_lock;
|
|
QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
|
|
CoQueue flush_queue; /* Serializing flush queue */
|
|
bool active_flush_req; /* Flush request in flight? */
|
|
|
|
/* Only read/written by whoever has set active_flush_req to true. */
|
|
unsigned int flushed_gen; /* Flushed write generation */
|
|
|
|
/* BdrvChild links to this node may never be frozen */
|
|
bool never_freeze;
|
|
|
|
/* Lock for block-status cache RCU writers */
|
|
CoMutex bsc_modify_lock;
|
|
/* Always non-NULL, but must only be dereferenced under an RCU read guard */
|
|
BdrvBlockStatusCache *block_status_cache;
|
|
|
|
/* array of write pointers' location of each zone in the zoned device. */
|
|
BlockZoneWps *wps;
|
|
};
|
|
|
|
struct BlockBackendRootState {
|
|
int open_flags;
|
|
BlockdevDetectZeroesOptions detect_zeroes;
|
|
};
|
|
|
|
typedef enum BlockMirrorBackingMode {
|
|
/*
|
|
* Reuse the existing backing chain from the source for the target.
|
|
* - sync=full: Set backing BDS to NULL.
|
|
* - sync=top: Use source's backing BDS.
|
|
* - sync=none: Use source as the backing BDS.
|
|
*/
|
|
MIRROR_SOURCE_BACKING_CHAIN,
|
|
|
|
/* Open the target's backing chain completely anew */
|
|
MIRROR_OPEN_BACKING_CHAIN,
|
|
|
|
/* Do not change the target's backing BDS after job completion */
|
|
MIRROR_LEAVE_BACKING_CHAIN,
|
|
} BlockMirrorBackingMode;
|
|
|
|
|
|
/*
|
|
* Essential block drivers which must always be statically linked into qemu, and
|
|
* which therefore can be accessed without using bdrv_find_format()
|
|
*/
|
|
extern BlockDriver bdrv_file;
|
|
extern BlockDriver bdrv_raw;
|
|
extern BlockDriver bdrv_qcow2;
|
|
|
|
extern unsigned int bdrv_drain_all_count;
|
|
extern QemuOptsList bdrv_create_opts_simple;
|
|
|
|
/*
|
|
* Common functions that are neither I/O nor Global State.
|
|
*
|
|
* See include/block/block-common.h for more information about
|
|
* the Common API.
|
|
*/
|
|
|
|
static inline BlockDriverState *child_bs(BdrvChild *child)
|
|
{
|
|
return child ? child->bs : NULL;
|
|
}
|
|
|
|
int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp);
|
|
char *create_tmp_file(Error **errp);
|
|
void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
|
|
QDict *options);
|
|
|
|
|
|
int bdrv_check_qiov_request(int64_t offset, int64_t bytes,
|
|
QEMUIOVector *qiov, size_t qiov_offset,
|
|
Error **errp);
|
|
|
|
#ifdef _WIN32
|
|
int is_windows_drive(const char *filename);
|
|
#endif
|
|
|
|
#endif /* BLOCK_INT_COMMON_H */
|