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qemu-e2k/include/block/block_int.h
Eric Blake efa6e2ed64 block: Align block status requests 
Any device that has request_alignment greater than 512 should be
unable to report status at a finer granularity; it may also be
simpler for such devices to be guaranteed that the block layer
has rounded things out to the granularity boundary (the way the
block layer already rounds all other I/O out).  Besides, getting
the code correct for super-sector alignment also benefits us
for the fact that our public interface now has byte granularity,
even though none of our drivers have byte-level callbacks.

Add an assertion in blkdebug that proves that the block layer
never requests status of unaligned sections, similar to what it
does on other requests (while still keeping the generic helper
in place for when future patches add a throttle driver).  Note
that iotest 177 already covers this (it would fail if you use
just the blkdebug.c hunk without the io.c changes).  Meanwhile,
we can drop assertions in callers that no longer have to pass
in sector-aligned addresses.

There is a mid-function scope added for 'count' and 'longret',
for a couple of reasons: first, an upcoming patch will add an
'if' statement that checks whether a driver has an old- or
new-style callback, and can conveniently use the same scope for
less indentation churn at that time.  Second, since we are
trying to get rid of sector-based computations, wrapping things
in a scope makes it easier to group and see what will be
deleted in a final cleanup patch once all drivers have been
converted to the new-style callback.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-26 14:45:57 +02:00

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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 "qemu/option.h"
#include "qemu/queue.h"
#include "qemu/coroutine.h"
#include "qemu/stats64.h"
#include "qemu/timer.h"
#include "qapi-types.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,
};
typedef struct BdrvTrackedRequest {
BlockDriverState *bs;
int64_t offset;
unsigned int bytes;
enum BdrvTrackedRequestType type;
bool serialising;
int64_t overlap_offset;
unsigned int 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);
int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
Error **errp);
void (*bdrv_close)(BlockDriverState *bs);
int (*bdrv_create)(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_readv)(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque);
BlockAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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 coroutine_fn (*bdrv_co_writev_flags)(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);
/*
* Building block for bdrv_block_status[_above] and
* bdrv_is_allocated[_above]. The driver should answer only
* according to the current layer, and should not set
* BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW. See block.h
* for the meaning of _DATA, _ZERO, and _OFFSET_VALID. The block
* layer guarantees input aligned to request_alignment, as well as
* non-NULL pnum and file.
*/
int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum,
BlockDriverState **file);
/*
* Invalidate any cached meta-data.
*/
void (*bdrv_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);
const char *protocol_name;
int (*bdrv_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 (*bdrv_check)(BlockDriverState *bs, BdrvCheckResult *result,
BdrvCheckMode fix);
int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts,
BlockDriverAmendStatusCB *status_cb,
void *cb_opaque);
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);
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;
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.
*
* 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);
/* 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) */
unsigned int supported_write_flags;
/* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
* BDRV_REQ_MAY_UNMAP) */
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;
/* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic
* ops.
*/
bool wakeup;
/* 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;
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);
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.
* @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, 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,
BlockJobTxn *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_get_block_status() to
* their file.
*/
int64_t coroutine_fn bdrv_co_get_block_status_from_file(BlockDriverState *bs,
int64_t sector_num,
int nb_sectors,
int *pnum,
BlockDriverState **file);
/*
* Default implementation for drivers to pass bdrv_co_get_block_status() to
* their backing file.
*/
int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs,
int64_t sector_num,
int nb_sectors,
int *pnum,
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);
bool bdrv_requests_pending(BlockDriverState *bs);
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);
#endif /* BLOCK_INT_H */
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