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qemu/include/block/block_int.h

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/*
* QEMU System Emulator block driver
*
* Copyright (c) 2003 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef BLOCK_INT_H
#define BLOCK_INT_H
#include "block/accounting.h"
#include "block/block.h"
#include "block/aio-wait.h"
#include "qemu/queue.h"
#include "qemu/coroutine.h"
#include "qemu/stats64.h"
#include "qemu/timer.h"
#include "qemu/hbitmap.h"
#include "block/snapshot.h"
#include "qemu/main-loop.h"
#include "qemu/throttle.h"
#define BLOCK_FLAG_LAZY_REFCOUNTS 8
#define BLOCK_OPT_SIZE "size"
#define BLOCK_OPT_ENCRYPT "encryption"
#define BLOCK_OPT_ENCRYPT_FORMAT "encrypt.format"
#define BLOCK_OPT_COMPAT6 "compat6"
#define BLOCK_OPT_HWVERSION "hwversion"
#define BLOCK_OPT_BACKING_FILE "backing_file"
#define BLOCK_OPT_BACKING_FMT "backing_fmt"
#define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
#define BLOCK_OPT_TABLE_SIZE "table_size"
#define BLOCK_OPT_PREALLOC "preallocation"
#define BLOCK_OPT_SUBFMT "subformat"
#define BLOCK_OPT_COMPAT_LEVEL "compat"
#define BLOCK_OPT_LAZY_REFCOUNTS "lazy_refcounts"
#define BLOCK_OPT_ADAPTER_TYPE "adapter_type"
#define BLOCK_OPT_REDUNDANCY "redundancy"
#define BLOCK_OPT_NOCOW "nocow"
#define BLOCK_OPT_OBJECT_SIZE "object_size"
#define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
#define BLOCK_PROBE_BUF_SIZE 512
enum BdrvTrackedRequestType {
BDRV_TRACKED_READ,
BDRV_TRACKED_WRITE,
BDRV_TRACKED_DISCARD,
BDRV_TRACKED_TRUNCATE,
};
typedef struct BdrvTrackedRequest {
BlockDriverState *bs;
int64_t offset;
uint64_t bytes;
enum BdrvTrackedRequestType type;
bool serialising;
int64_t overlap_offset;
uint64_t overlap_bytes;
QLIST_ENTRY(BdrvTrackedRequest) list;
Coroutine *co; /* owner, used for deadlock detection */
CoQueue wait_queue; /* coroutines blocked on this request */
struct BdrvTrackedRequest *waiting_for;
} BdrvTrackedRequest;
struct BlockDriver {
const char *format_name;
int instance_size;
/* set to true if the BlockDriver is a block filter. Block filters pass
* certain callbacks that refer to data (see block.c) to their bs->file if
* the driver doesn't implement them. Drivers that do not wish to forward
* must implement them and return -ENOTSUP.
*/
bool is_filter;
/* for snapshots block filter like Quorum can implement the
* following recursive callback.
* It's purpose is to recurse on the filter children while calling
* bdrv_recurse_is_first_non_filter on them.
* For a sample implementation look in the future Quorum block filter.
*/
bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs,
BlockDriverState *candidate);
int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
int (*bdrv_probe_device)(const char *filename);
/* Any driver implementing this callback is expected to be able to handle
* NULL file names in its .bdrv_open() implementation */
void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp);
/* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
* this field set to true, except ones that are defined only by their
* child's bs.
* An example of the last type will be the quorum block driver.
*/
bool bdrv_needs_filename;
/* Set if a driver can support backing files */
bool supports_backing;
/* For handling image reopen for split or non-split files */
int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state,
BlockReopenQueue *queue, Error **errp);
void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state);
void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state);
void (*bdrv_join_options)(QDict *options, QDict *old_options);
int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags,
Error **errp);
/* Protocol drivers should implement this instead of bdrv_open */
int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
Error **errp);
void (*bdrv_close)(BlockDriverState *bs);
int coroutine_fn (*bdrv_co_create)(BlockdevCreateOptions *opts,
Error **errp);
int coroutine_fn (*bdrv_co_create_opts)(const char *filename,
QemuOpts *opts,
Error **errp);
int (*bdrv_make_empty)(BlockDriverState *bs);
void (*bdrv_refresh_filename)(BlockDriverState *bs, QDict *options);
/* aio */
BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags,
BlockCompletionFunc *cb, void *opaque);
BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags,
BlockCompletionFunc *cb, void *opaque);
BlockAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
BlockCompletionFunc *cb, void *opaque);
BlockAIOCB *(*bdrv_aio_pdiscard)(BlockDriverState *bs,
int64_t offset, int bytes,
BlockCompletionFunc *cb, void *opaque);
int coroutine_fn (*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 (*bdrv_co_preadv)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
int coroutine_fn (*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 (*bdrv_co_pwritev)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int 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 (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs,
int64_t offset, int bytes, BdrvRequestFlags flags);
int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs,
int64_t offset, int 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 (*bdrv_co_copy_range_from)(BlockDriverState *bs,
BdrvChild *src,
uint64_t offset,
BdrvChild *dst,
uint64_t dst_offset,
uint64_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 (*bdrv_co_copy_range_to)(BlockDriverState *bs,
BdrvChild *src,
uint64_t src_offset,
BdrvChild *dst,
uint64_t dst_offset,
uint64_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.
*/
int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs,
bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
int64_t *map, BlockDriverState **file);
/*
* Invalidate any cached meta-data.
*/
void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs,
Error **errp);
int (*bdrv_inactivate)(BlockDriverState *bs);
/*
* 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 (*bdrv_co_flush)(BlockDriverState *bs);
/*
* 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 (*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 (*bdrv_co_flush_to_os)(BlockDriverState *bs);
/*
* Drivers setting this field must be able to work with just a plain
* filename with '<protocol_name>:' as a prefix, and no other options.
* Options may be extracted from the filename by implementing
* bdrv_parse_filename.
*/
const char *protocol_name;
int coroutine_fn (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset,
PreallocMode prealloc, Error **errp);
int64_t (*bdrv_getlength)(BlockDriverState *bs);
bool has_variable_length;
int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs,
Error **errp);
int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov);
int (*bdrv_snapshot_create)(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info);
int (*bdrv_snapshot_goto)(BlockDriverState *bs,
const char *snapshot_id);
int (*bdrv_snapshot_delete)(BlockDriverState *bs,
const char *snapshot_id,
const char *name,
Error **errp);
int (*bdrv_snapshot_list)(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info);
int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
const char *snapshot_id,
const char *name,
Error **errp);
int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs);
int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs,
QEMUIOVector *qiov,
int64_t pos);
int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs,
QEMUIOVector *qiov,
int64_t pos);
int (*bdrv_change_backing_file)(BlockDriverState *bs,
const char *backing_file, const char *backing_fmt);
/* removable device specific */
bool (*bdrv_is_inserted)(BlockDriverState *bs);
void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
/* to control generic scsi devices */
BlockAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockCompletionFunc *cb, void *opaque);
int coroutine_fn (*bdrv_co_ioctl)(BlockDriverState *bs,
unsigned long int req, void *buf);
/* List of options for creating images, terminated by name == NULL */
QemuOptsList *create_opts;
/*
* Returns 0 for completed check, -errno for internal errors.
* The check results are stored in result.
*/
int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs,
BdrvCheckResult *result,
BdrvCheckMode fix);
int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts,
BlockDriverAmendStatusCB *status_cb,
void *cb_opaque,
Error **errp);
void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event);
/* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event,
const char *tag);
int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs,
const char *tag);
int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag);
bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag);
void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp);
/*
* Returns 1 if newly created images are guaranteed to contain only
* zeros, 0 otherwise.
*/
int (*bdrv_has_zero_init)(BlockDriverState *bs);
/* Remove fd handlers, timers, and other event loop callbacks so the event
* loop is no longer in use. Called with no in-flight requests and in
* depth-first traversal order with parents before child nodes.
*/
void (*bdrv_detach_aio_context)(BlockDriverState *bs);
/* Add fd handlers, timers, and other event loop callbacks so I/O requests
* can be processed again. Called with no in-flight requests and in
* depth-first traversal order with child nodes before parent nodes.
*/
void (*bdrv_attach_aio_context)(BlockDriverState *bs,
AioContext *new_context);
/* io queue for linux-aio */
void (*bdrv_io_plug)(BlockDriverState *bs);
void (*bdrv_io_unplug)(BlockDriverState *bs);
/**
* Try to get @bs's logical and physical block size.
* On success, store them in @bsz and return zero.
* On failure, return negative errno.
*/
int (*bdrv_probe_blocksizes)(BlockDriverState *bs, BlockSizes *bsz);
/**
* Try to get @bs's geometry (cyls, heads, sectors)
* On success, store them in @geo and return 0.
* On failure return -errno.
* Only drivers that want to override guest geometry implement this
* callback; see hd_geometry_guess().
*/
int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
/**
* bdrv_co_drain_begin is called if implemented in the beginning of a
* drain operation to drain and stop any internal sources of requests in
* the driver.
* bdrv_co_drain_end is called if implemented at the end of the drain.
*
* They should be used by the driver to e.g. manage scheduled I/O
* requests, or toggle an internal state. After the end of the drain new
* requests will continue normally.
*/
void coroutine_fn (*bdrv_co_drain_begin)(BlockDriverState *bs);
void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs);
void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child,
Error **errp);
void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child,
Error **errp);
/**
* Informs the block driver that a permission change is intended. The
* driver checks whether the change is permissible and may take other
* preparations for the change (e.g. get file system locks). This operation
* is always followed either by a call to either .bdrv_set_perm or
* .bdrv_abort_perm_update.
*
* Checks whether the requested set of cumulative permissions in @perm
* can be granted for accessing @bs and whether no other users are using
* permissions other than those given in @shared (both arguments take
* BLK_PERM_* bitmasks).
*
* If both conditions are met, 0 is returned. Otherwise, -errno is returned
* and errp is set to an error describing the conflict.
*/
int (*bdrv_check_perm)(BlockDriverState *bs, uint64_t perm,
uint64_t shared, Error **errp);
/**
* Called to inform the driver that the set of cumulative set of used
* permissions for @bs has changed to @perm, and the set of sharable
* permission to @shared. The driver can use this to propagate changes to
* its children (i.e. request permissions only if a parent actually needs
* them).
*
* This function is only invoked after bdrv_check_perm(), so block drivers
* may rely on preparations made in their .bdrv_check_perm implementation.
*/
void (*bdrv_set_perm)(BlockDriverState *bs, uint64_t perm, uint64_t shared);
/*
* Called to inform the driver that after a previous bdrv_check_perm()
* call, the permission update is not performed and any preparations made
* for it (e.g. taken file locks) need to be undone.
*
* This function can be called even for nodes that never saw a
* bdrv_check_perm() call. It is a no-op then.
*/
void (*bdrv_abort_perm_update)(BlockDriverState *bs);
/**
* Returns in @nperm and @nshared the permissions that the driver for @bs
* needs on its child @c, based on the cumulative permissions requested by
* the parents in @parent_perm and @parent_shared.
*
* If @c is NULL, return the permissions for attaching a new child for the
* given @role.
*
* If @reopen_queue is non-NULL, don't return the currently needed
* permissions, but those that will be needed after applying the
* @reopen_queue.
*/
void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
BlockReopenQueue *reopen_queue,
uint64_t parent_perm, uint64_t parent_shared,
uint64_t *nperm, uint64_t *nshared);
/**
* Bitmaps should be marked as 'IN_USE' in the image on reopening image
* as rw. This handler should realize it. It also should unset readonly
* field of BlockDirtyBitmap's in case of success.
*/
int (*bdrv_reopen_bitmaps_rw)(BlockDriverState *bs, Error **errp);
bool (*bdrv_can_store_new_dirty_bitmap)(BlockDriverState *bs,
const char *name,
uint32_t granularity,
Error **errp);
void (*bdrv_remove_persistent_dirty_bitmap)(BlockDriverState *bs,
const char *name,
Error **errp);
/**
* Register/unregister a buffer for I/O. For example, when the driver is
* interested to know the memory areas that will later be used in iovs, so
* that it can do IOMMU mapping with VFIO etc., in order to get better
* performance. In the case of VFIO drivers, this callback is used to do
* DMA mapping for hot buffers.
*/
void (*bdrv_register_buf)(BlockDriverState *bs, void *host, size_t size);
void (*bdrv_unregister_buf)(BlockDriverState *bs, void *host);
QLIST_ENTRY(BlockDriver) list;
};
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 (since it
* is signed, it must be < 2G, if set). Must be multiple of
* pdiscard_alignment, but need not be power of 2. May be 0 if no
* inherent 32-bit limit */
int32_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 (since it is
* signed, it must be < 2G, if set). Must be multiple of
* pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */
int32_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;
/* 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;
} 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 BdrvChildRole {
/* 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;
void (*inherit_options)(int *child_flags, QDict *child_options,
int parent_flags, QDict *parent_options);
void (*change_media)(BdrvChild *child, bool load);
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);
/* 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);
/*
* 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 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 (*attach)(BdrvChild *child);
void (*detach)(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);
};
extern const BdrvChildRole child_file;
extern const BdrvChildRole child_format;
extern const BdrvChildRole child_backing;
struct BdrvChild {
BlockDriverState *bs;
char *name;
const 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;
QLIST_ENTRY(BdrvChild) next;
QLIST_ENTRY(BdrvChild) next_parent;
};
/*
* Note: the function bdrv_append() copies and swaps contents of
* BlockDriverStates, so if you add new fields to this struct, please
* inspect bdrv_append() to determine if the new fields need to be
* copied as well.
*/
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 read_only; /* if true, the media is read only */
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];
char backing_file[PATH_MAX]; /* if non zero, the image is a diff of
this file image */
char backing_format[16]; /* if non-zero and backing_file exists */
QDict *full_open_options;
char exact_filename[PATH_MAX];
BdrvChild *backing;
BdrvChild *file;
/* I/O Limits */
BlockLimits bl;
/* 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. */
unsigned int supported_write_flags;
/* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
* BDRV_REQ_MAY_UNMAP, BDRV_REQ_WRITE_UNCHANGED) */
unsigned int supported_zero_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 */
QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
/* long-running background operation */
BlockJob *job;
/* 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;
QLIST_HEAD(, BdrvChild) children;
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;
/* Callback before write request is processed */
NotifierWithReturnList before_write_notifiers;
/* threshold limit for writes, in bytes. "High water mark". */
uint64_t write_threshold_offset;
NotifierWithReturn write_threshold_notifier;
/* 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;
/* Kicked to signal main loop when a request completes. */
AioWait wait;
/* counter for nested bdrv_io_plug.
* Accessed with atomic ops.
*/
unsigned io_plugged;
/* 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;
int recursive_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 */
};
struct BlockBackendRootState {
int open_flags;
bool read_only;
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;
static inline BlockDriverState *backing_bs(BlockDriverState *bs)
{
return bs->backing ? bs->backing->bs : NULL;
}
/* 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;
int coroutine_fn bdrv_co_preadv(BdrvChild *child,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
extern unsigned int bdrv_drain_all_count;
void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent);
void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent);
int get_tmp_filename(char *filename, int size);
BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
const char *filename);
void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix,
QDict *options);
/**
* bdrv_add_before_write_notifier:
*
* Register a callback that is invoked before write requests are processed but
* after any throttling or waiting for overlapping requests.
*/
void bdrv_add_before_write_notifier(BlockDriverState *bs,
NotifierWithReturn *notifier);
/**
* bdrv_detach_aio_context:
*
* May be called from .bdrv_detach_aio_context() to detach children from the
* current #AioContext. This is only needed by block drivers that manage their
* own children. Both ->file and ->backing are automatically handled and
* block drivers should not call this function on them explicitly.
*/
void bdrv_detach_aio_context(BlockDriverState *bs);
/**
* bdrv_attach_aio_context:
*
* May be called from .bdrv_attach_aio_context() to attach children to the new
* #AioContext. This is only needed by block drivers that manage their own
* children. Both ->file and ->backing are automatically handled and block
* drivers should not call this function on them explicitly.
*/
void bdrv_attach_aio_context(BlockDriverState *bs,
AioContext *new_context);
/**
* bdrv_add_aio_context_notifier:
*
* If a long-running job intends to be always run in the same AioContext as a
* certain BDS, it may use this function to be notified of changes regarding the
* association of the BDS to an AioContext.
*
* attached_aio_context() is called after the target BDS has been attached to a
* new AioContext; detach_aio_context() is called before the target BDS is being
* detached from its old AioContext.
*/
void bdrv_add_aio_context_notifier(BlockDriverState *bs,
void (*attached_aio_context)(AioContext *new_context, void *opaque),
void (*detach_aio_context)(void *opaque), void *opaque);
/**
* bdrv_remove_aio_context_notifier:
*
* Unsubscribe of change notifications regarding the BDS's AioContext. The
* parameters given here have to be the same as those given to
* bdrv_add_aio_context_notifier().
*/
void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
void (*aio_context_attached)(AioContext *,
void *),
void (*aio_context_detached)(void *),
void *opaque);
/**
* bdrv_wakeup:
* @bs: The BlockDriverState for which an I/O operation has been completed.
*
* Wake up the main thread if it is waiting on BDRV_POLL_WHILE. During
* synchronous I/O on a BlockDriverState that is attached to another
* I/O thread, the main thread lets the I/O thread's event loop run,
* waiting for the I/O operation to complete. A bdrv_wakeup will wake
* up the main thread if necessary.
*
* Manual calls to bdrv_wakeup are rarely necessary, because
* bdrv_dec_in_flight already calls it.
*/
void bdrv_wakeup(BlockDriverState *bs);
#ifdef _WIN32
int is_windows_drive(const char *filename);
#endif
/**
* stream_start:
* @job_id: The id of the newly-created job, or %NULL to use the
* device name of @bs.
* @bs: Block device to operate on.
* @base: Block device that will become the new base, or %NULL to
* flatten the whole backing file chain onto @bs.
* @backing_file_str: The file name that will be written to @bs as the
* the new backing file if the job completes. Ignored if @base is %NULL.
* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
* @on_error: The action to take upon error.
* @errp: Error object.
*
* Start a streaming operation on @bs. Clusters that are unallocated
* in @bs, but allocated in any image between @base and @bs (both
* exclusive) will be written to @bs. At the end of a successful
* streaming job, the backing file of @bs will be changed to
* @backing_file_str in the written image and to @base in the live
* BlockDriverState.
*/
void stream_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *base, const char *backing_file_str,
int64_t speed, BlockdevOnError on_error, Error **errp);
/**
* commit_start:
* @job_id: The id of the newly-created job, or %NULL to use the
* device name of @bs.
* @bs: Active block device.
* @top: Top block device to be committed.
* @base: Block device that will be written into, and become the new top.
* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
* @on_error: The action to take upon error.
* @backing_file_str: String to use as the backing file in @top's overlay
* @filter_node_name: The node name that should be assigned to the filter
* driver that the commit job inserts into the graph above @top. NULL means
* that a node name should be autogenerated.
* @errp: Error object.
*
*/
void commit_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *base, BlockDriverState *top, int64_t speed,
BlockdevOnError on_error, const char *backing_file_str,
const char *filter_node_name, Error **errp);
/**
* commit_active_start:
* @job_id: The id of the newly-created job, or %NULL to use the
* device name of @bs.
* @bs: Active block device to be committed.
* @base: Block device that will be written into, and become the new top.
* @creation_flags: Flags that control the behavior of the Job lifetime.
* See @BlockJobCreateFlags
* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
* @on_error: The action to take upon error.
* @filter_node_name: The node name that should be assigned to the filter
* driver that the commit job inserts into the graph above @bs. NULL means that
* a node name should be autogenerated.
* @cb: Completion function for the job.
* @opaque: Opaque pointer value passed to @cb.
* @auto_complete: Auto complete the job.
* @errp: Error object.
*
*/
void commit_active_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *base, int creation_flags,
int64_t speed, BlockdevOnError on_error,
const char *filter_node_name,
BlockCompletionFunc *cb, void *opaque,
bool auto_complete, Error **errp);
/*
* mirror_start:
* @job_id: The id of the newly-created job, or %NULL to use the
* device name of @bs.
* @bs: Block device to operate on.
* @target: Block device to write to.
* @replaces: Block graph node name to replace once the mirror is done. Can
* only be used when full mirroring is selected.
* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
* @granularity: The chosen granularity for the dirty bitmap.
* @buf_size: The amount of data that can be in flight at one time.
* @mode: Whether to collapse all images in the chain to the target.
* @backing_mode: How to establish the target's backing chain after completion.
* @on_source_error: The action to take upon error reading from the source.
* @on_target_error: The action to take upon error writing to the target.
* @unmap: Whether to unmap target where source sectors only contain zeroes.
* @filter_node_name: The node name that should be assigned to the filter
* driver that the mirror job inserts into the graph above @bs. NULL means that
* a node name should be autogenerated.
* @copy_mode: When to trigger writes to the target.
* @errp: Error object.
*
* Start a mirroring operation on @bs. Clusters that are allocated
* in @bs will be written to @target until the job is cancelled or
* manually completed. At the end of a successful mirroring job,
* @bs will be switched to read from @target.
*/
void mirror_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *target, const char *replaces,
int64_t speed, uint32_t granularity, int64_t buf_size,
MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
bool unmap, const char *filter_node_name,
MirrorCopyMode copy_mode, Error **errp);
/*
* backup_job_create:
* @job_id: The id of the newly-created job, or %NULL to use the
* device name of @bs.
* @bs: Block device to operate on.
* @target: Block device to write to.
* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
* @sync_mode: What parts of the disk image should be copied to the destination.
* @sync_bitmap: The dirty bitmap if sync_mode is MIRROR_SYNC_MODE_INCREMENTAL.
* @on_source_error: The action to take upon error reading from the source.
* @on_target_error: The action to take upon error writing to the target.
* @creation_flags: Flags that control the behavior of the Job lifetime.
* See @BlockJobCreateFlags
* @cb: Completion function for the job.
* @opaque: Opaque pointer value passed to @cb.
* @txn: Transaction that this job is part of (may be NULL).
*
* Create a backup operation on @bs. Clusters in @bs are written to @target
* until the job is cancelled or manually completed.
*/
BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
BlockDriverState *target, int64_t speed,
MirrorSyncMode sync_mode,
BdrvDirtyBitmap *sync_bitmap,
bool compress,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
int creation_flags,
BlockCompletionFunc *cb, void *opaque,
JobTxn *txn, Error **errp);
void hmp_drive_add_node(Monitor *mon, const char *optstr);
BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
const char *child_name,
const BdrvChildRole *child_role,
uint64_t perm, uint64_t shared_perm,
void *opaque, Error **errp);
void bdrv_root_unref_child(BdrvChild *child);
int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
Error **errp);
/* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
* block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to
* all children */
void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared);
/* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
* (non-raw) image formats: Like above for bs->backing, but for bs->file it
* requires WRITE | RESIZE for read-write images, always requires
* CONSISTENT_READ and doesn't share WRITE. */
void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared);
/*
* Default implementation for drivers to pass bdrv_co_block_status() to
* their file.
*/
int coroutine_fn bdrv_co_block_status_from_file(BlockDriverState *bs,
bool want_zero,
int64_t offset,
int64_t bytes,
int64_t *pnum,
int64_t *map,
BlockDriverState **file);
/*
* Default implementation for drivers to pass bdrv_co_block_status() to
* their backing file.
*/
int coroutine_fn bdrv_co_block_status_from_backing(BlockDriverState *bs,
bool want_zero,
int64_t offset,
int64_t bytes,
int64_t *pnum,
int64_t *map,
BlockDriverState **file);
const char *bdrv_get_parent_name(const BlockDriverState *bs);
void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp);
bool blk_dev_has_removable_media(BlockBackend *blk);
bool blk_dev_has_tray(BlockBackend *blk);
void blk_dev_eject_request(BlockBackend *blk, bool force);
bool blk_dev_is_tray_open(BlockBackend *blk);
bool blk_dev_is_medium_locked(BlockBackend *blk);
void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes);
void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in);
void bdrv_inc_in_flight(BlockDriverState *bs);
void bdrv_dec_in_flight(BlockDriverState *bs);
void blockdev_close_all_bdrv_states(void);
int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, uint64_t src_offset,
BdrvChild *dst, uint64_t dst_offset,
uint64_t bytes,
BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags);
int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, uint64_t src_offset,
BdrvChild *dst, uint64_t dst_offset,
uint64_t bytes,
BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags);
int refresh_total_sectors(BlockDriverState *bs, int64_t hint);
#endif /* BLOCK_INT_H */
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