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qemu/include/block/block_int.h
Max Reitz 0b877d09df block: Leave BDS.backing_{file,format} constant 
Parts of the block layer treat BDS.backing_file as if it were whatever
the image header says (i.e., if it is a relative path, it is relative to
the overlay), other parts treat it like a cache for
bs->backing->bs->filename (relative paths are relative to the CWD).
Considering bs->backing->bs->filename exists, let us make it mean the
former.

Among other things, this now allows the user to specify a base when
using qemu-img to commit an image file in a directory that is not the
CWD (assuming, everything uses relative filenames).

Before this patch:

$ ./qemu-img create -f qcow2 foo/bot.qcow2 1M
$ ./qemu-img create -f qcow2 -b bot.qcow2 foo/mid.qcow2
$ ./qemu-img create -f qcow2 -b mid.qcow2 foo/top.qcow2
$ ./qemu-img commit -b mid.qcow2 foo/top.qcow2
qemu-img: Did not find 'mid.qcow2' in the backing chain of 'foo/top.qcow2'
$ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2
qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.qcow2'
$ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2
qemu-img: Did not find '[...]/foo/mid.qcow2' in the backing chain of 'foo/top.qcow2'

After this patch:

$ ./qemu-img commit -b mid.qcow2 foo/top.qcow2
Image committed.
$ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2
qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.qcow2'
$ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2
Image committed.

With this change, bdrv_find_backing_image() must look at whether the
user has overridden a BDS's backing file.  If so, it can no longer use
bs->backing_file, but must instead compare the given filename against
the backing node's filename directly.

Note that this changes the QAPI output for a node's backing_file.  We
had very inconsistent output there (sometimes what the image header
said, sometimes the actual filename of the backing image).  This
inconsistent output was effectively useless, so we have to decide one
way or the other.  Considering that bs->backing_file usually at runtime
contained the path to the image relative to qemu's CWD (or absolute),
this patch changes QAPI's backing_file to always report the
bs->backing->bs->filename from now on.  If you want to receive the image
header information, you have to refer to full-backing-filename.

This necessitates a change to iotest 228.  The interesting information
it really wanted is the image header, and it can get that now, but it
has to use full-backing-filename instead of backing_file.  Because of
this patch's changes to bs->backing_file's behavior, we also need some
reference output changes.

Along with the changes to bs->backing_file, stop updating
BDS.backing_format in bdrv_backing_attach() as well.  This way,
ImageInfo's backing-filename and backing-filename-format fields will
represent what the image header says and nothing else.

iotest 245 changes in behavior: With the backing node no longer
overriding the parent node's backing_file string, you can now omit the
@backing option when reopening a node with neither a default nor a
current backing file even if it used to have a backing node at some
point.

273 also changes: The base image is opened without a format layer, so
ImageInfo.backing-filename-format used to report "file" for the base
image's overlay after blockdev-snapshot.  However, the image header
never says "file" anywhere, so it now reports $IMGFMT.

Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-07 12:31:31 +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 "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/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_EXTENT_SIZE_HINT "extent_size_hint"
#define BLOCK_OPT_OBJECT_SIZE "object_size"
#define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
#define BLOCK_OPT_DATA_FILE "data_file"
#define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
#define BLOCK_OPT_COMPRESSION_TYPE "compression_type"
#define BLOCK_OPT_EXTL2 "extended_l2"
#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
* or bs->backing (whichever one exists) if the driver doesn't implement
* them. Drivers that do not wish to forward must implement them and return
* -ENOTSUP.
* Note that filters are not allowed to modify data.
*
* Filters generally cannot have more than a single filtered child,
* because the data they present must at all times be the same as
* that on their filtered child. That would be impossible to
* achieve for multiple filtered children.
* (And this filtered child must then be bs->file or bs->backing.)
*/
bool is_filter;
/*
* Set to true if the BlockDriver is a format driver. Format nodes
* generally do not expect their children to be other format nodes
* (except for backing files), and so format probing is disabled
* on those children.
*/
bool is_format;
/*
* Return true if @to_replace can be replaced by a BDS with the
* same data as @bs without it affecting @bs's behavior (that is,
* without it being visible to @bs's parents).
*/
bool (*bdrv_recurse_can_replace)(BlockDriverState *bs,
BlockDriverState *to_replace);
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. This also implies the
* following semantics:
*
* - Return status 0 of .bdrv_co_block_status means that corresponding
* blocks are not allocated in this layer of backing-chain
* - For such (unallocated) blocks, read will:
* - fill buffer with zeros if there is no backing file
* - read from the backing file otherwise, where the block layer
* takes care of reading zeros beyond EOF if backing file is short
*/
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_commit_post)(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)(BlockDriver *drv,
const char *filename,
QemuOpts *opts,
Error **errp);
int coroutine_fn (*bdrv_co_amend)(BlockDriverState *bs,
BlockdevAmendOptions *opts,
bool force,
Error **errp);
int (*bdrv_amend_options)(BlockDriverState *bs,
QemuOpts *opts,
BlockDriverAmendStatusCB *status_cb,
void *cb_opaque,
bool force,
Error **errp);
int (*bdrv_make_empty)(BlockDriverState *bs);
/*
* Refreshes the bs->exact_filename field. If that is impossible,
* bs->exact_filename has to be left empty.
*/
void (*bdrv_refresh_filename)(BlockDriverState *bs);
/*
* Gathers the open options for all children into @target.
* A simple format driver (without backing file support) might
* implement this function like this:
*
* QINCREF(bs->file->bs->full_open_options);
* qdict_put(target, "file", bs->file->bs->full_open_options);
*
* If not specified, the generic implementation will simply put
* all children's options under their respective name.
*
* @backing_overridden is true when bs->backing seems not to be
* the child that would result from opening bs->backing_file.
* Therefore, if it is true, the backing child's options should be
* gathered; otherwise, there is no need since the backing child
* is the one implied by the image header.
*
* Note that ideally this function would not be needed. Every
* block driver which implements it is probably doing something
* shady regarding its runtime option structure.
*/
void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target,
bool backing_overridden);
/*
* Returns an allocated string which is the directory name of this BDS: It
* will be used to make relative filenames absolute by prepending this
* function's return value to them.
*/
char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp);
/* 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_preadv_part)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, 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);
int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, 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);
/* Delete a created file. */
int coroutine_fn (*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 (*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;
/*
* 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 (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
BdrvRequestFlags flags, 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 coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
size_t qiov_offset);
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,
Error **errp);
BlockStatsSpecific *(*bdrv_get_specific_stats)(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;
/* List of options for image amend */
QemuOptsList *amend_opts;
/*
* If this driver supports reopening images this contains a
* NULL-terminated list of the runtime options that can be
* modified. If an option in this list is unspecified during
* reopen then it _must_ be reset to its default value or return
* an error.
*/
const char *const *mutable_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);
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 @child_class and @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,
BdrvChildRole role,
BlockReopenQueue *reopen_queue,
uint64_t parent_perm, uint64_t parent_shared,
uint64_t *nperm, uint64_t *nshared);
bool (*bdrv_supports_persistent_dirty_bitmap)(BlockDriverState *bs);
bool (*bdrv_co_can_store_new_dirty_bitmap)(BlockDriverState *bs,
const char *name,
uint32_t granularity,
Error **errp);
int (*bdrv_co_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;
/* Pointer to a NULL-terminated array of names of strong options
* that can be specified for bdrv_open(). A strong option is one
* that changes the data of a BDS.
* If this pointer is NULL, the array is considered empty.
* "filename" and "driver" are always considered strong. */
const char *const *strong_runtime_opts;
};
static inline bool 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 (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 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;
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);
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).
*
* If drained_end() schedules background operations, it must atomically
* increment *drained_end_counter for each such operation and atomically
* decrement it once the operation has settled.
*
* 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, int *drained_end_counter);
/*
* 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);
bool (*can_set_aio_ctx)(BdrvChild *child, AioContext *ctx,
GSList **ignore, Error **errp);
void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore);
};
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;
/* backup of permissions during permission update procedure */
bool has_backup_perm;
uint64_t backup_perm;
uint64_t backup_shared_perm;
/*
* This link is frozen: the child can neither be replaced nor
* detached from the parent.
*/
bool frozen;
/*
* How many times the parent of this child has been drained
* (through klass->drained_*).
* Usually, this is equal to bs->quiesce_counter (potentially
* reduced by bdrv_drain_all_count). It may differ while the
* child is entering or leaving a drained section.
*/
int parent_quiesce_counter;
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];
/*
* 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];
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;
/*
* 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.
*/
unsigned int 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 */
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;
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;
/* 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 */
/* BdrvChild links to this node may never be frozen */
bool never_freeze;
};
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;
/* 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_preadv_part(BdrvChild *child,
int64_t offset, unsigned int bytes,
QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
int64_t offset, unsigned int bytes,
QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
static inline int coroutine_fn bdrv_co_pread(BdrvChild *child,
int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
return bdrv_co_preadv(child, offset, bytes, &qiov, flags);
}
static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child,
int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
return bdrv_co_pwritev(child, offset, bytes, &qiov, 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);
bool coroutine_fn bdrv_mark_request_serialising(BdrvTrackedRequest *req, uint64_t align);
BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs);
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);
bool bdrv_backing_overridden(BlockDriverState *bs);
/**
* 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_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.
* @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.
* @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,
int creation_flags, 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.
* @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.
* @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,
int creation_flags, 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.
*
*/
BlockJob *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.
* @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.
* @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.
* @zero_target: Whether the target should be explicitly zero-initialized
* @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,
int creation_flags, int64_t speed,
uint32_t granularity, int64_t buf_size,
MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
bool zero_target,
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 'bitmap' or 'incremental'
* @bitmap_mode: The bitmap synchronization policy to use.
* @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,
BitmapSyncMode bitmap_mode,
bool compress,
const char *filter_node_name,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
int creation_flags,
BlockCompletionFunc *cb, void *opaque,
JobTxn *txn, Error **errp);
BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
const char *child_name,
const BdrvChildClass *child_class,
BdrvChildRole child_role,
AioContext *ctx,
uint64_t perm, uint64_t shared_perm,
void *opaque, Error **errp);
void bdrv_root_unref_child(BdrvChild *child);
void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
uint64_t *shared_perm);
/**
* Sets a BdrvChild's permissions. Avoid if the parent is a BDS; use
* bdrv_child_refresh_perms() instead and make the parent's
* .bdrv_child_perm() implementation return the correct values.
*/
int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
Error **errp);
/**
* Calls bs->drv->bdrv_child_perm() and updates the child's permission
* masks with the result.
* Drivers should invoke this function whenever an event occurs that
* makes their .bdrv_child_perm() implementation return different
* values than before, but which will not result in the block layer
* automatically refreshing the permissions.
*/
int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp);
bool bdrv_recurse_can_replace(BlockDriverState *bs,
BlockDriverState *to_replace);
/*
* Default implementation for BlockDriver.bdrv_child_perm() that can
* be used by block filters and image formats, as long as they use the
* child_of_bds child class and set an appropriate BdrvChildRole.
*/
void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
BdrvChildRole role, BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared);
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_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup);
bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
const BdrvDirtyBitmap *src,
HBitmap **backup, bool lock);
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);
void bdrv_set_monitor_owned(BlockDriverState *bs);
BlockDriverState *bds_tree_init(QDict *bs_opts, Error **errp);
/**
* Simple implementation of bdrv_co_create_opts for protocol drivers
* which only support creation via opening a file
* (usually existing raw storage device)
*/
int coroutine_fn bdrv_co_create_opts_simple(BlockDriver *drv,
const char *filename,
QemuOpts *opts,
Error **errp);
extern QemuOptsList bdrv_create_opts_simple;
BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node,
const char *name,
BlockDriverState **pbs,
Error **errp);
BdrvDirtyBitmap *block_dirty_bitmap_merge(const char *node, const char *target,
BlockDirtyBitmapMergeSourceList *bms,
HBitmap **backup, Error **errp);
BdrvDirtyBitmap *block_dirty_bitmap_remove(const char *node, const char *name,
bool release,
BlockDriverState **bitmap_bs,
Error **errp);
BdrvChild *bdrv_cow_child(BlockDriverState *bs);
BdrvChild *bdrv_filter_child(BlockDriverState *bs);
BdrvChild *bdrv_filter_or_cow_child(BlockDriverState *bs);
BdrvChild *bdrv_primary_child(BlockDriverState *bs);
BlockDriverState *bdrv_skip_implicit_filters(BlockDriverState *bs);
BlockDriverState *bdrv_skip_filters(BlockDriverState *bs);
BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs);
static inline BlockDriverState *child_bs(BdrvChild *child)
{
return child ? child->bs : NULL;
}
static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs)
{
return child_bs(bdrv_cow_child(bs));
}
static inline BlockDriverState *bdrv_filter_bs(BlockDriverState *bs)
{
return child_bs(bdrv_filter_child(bs));
}
static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs)
{
return child_bs(bdrv_filter_or_cow_child(bs));
}
static inline BlockDriverState *bdrv_primary_bs(BlockDriverState *bs)
{
return child_bs(bdrv_primary_child(bs));
}
#endif /* BLOCK_INT_H */
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