/*
* 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_COMMON_H
#define BLOCK_COMMON_H
#include "block/aio.h"
#include "block/aio-wait.h"
#include "qemu/iov.h"
#include "qemu/coroutine.h"
#include "block/accounting.h"
#include "block/dirty-bitmap.h"
#include "block/blockjob.h"
#include "qemu/hbitmap.h"
#include "qemu/transactions.h"
/*
* generated_co_wrapper
*
* Function specifier, which does nothing but mark functions to be
* generated by scripts/block-coroutine-wrapper.py
*
* Read more in docs/devel/block-coroutine-wrapper.rst
*/
#define generated_co_wrapper
/* block.c */
typedef struct BlockDriver BlockDriver;
typedef struct BdrvChild BdrvChild;
typedef struct BdrvChildClass BdrvChildClass;
typedef struct BlockDriverInfo {
/* in bytes, 0 if irrelevant */
int cluster_size;
/* offset at which the VM state can be saved (0 if not possible) */
int64_t vm_state_offset;
bool is_dirty;
/*
* True if this block driver only supports compressed writes
*/
bool needs_compressed_writes;
} BlockDriverInfo;
typedef struct BlockFragInfo {
uint64_t allocated_clusters;
uint64_t total_clusters;
uint64_t fragmented_clusters;
uint64_t compressed_clusters;
} BlockFragInfo;
typedef enum {
BDRV_REQ_COPY_ON_READ = 0x1,
BDRV_REQ_ZERO_WRITE = 0x2,
/*
* The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
* that the block driver should unmap (discard) blocks if it is guaranteed
* that the result will read back as zeroes. The flag is only passed to the
* driver if the block device is opened with BDRV_O_UNMAP.
*/
BDRV_REQ_MAY_UNMAP = 0x4,
BDRV_REQ_FUA = 0x10,
BDRV_REQ_WRITE_COMPRESSED = 0x20,
/*
* Signifies that this write request will not change the visible disk
* content.
*/
BDRV_REQ_WRITE_UNCHANGED = 0x40,
/*
* Forces request serialisation. Use only with write requests.
*/
BDRV_REQ_SERIALISING = 0x80,
/*
* Execute the request only if the operation can be offloaded or otherwise
* be executed efficiently, but return an error instead of using a slow
* fallback.
*/
BDRV_REQ_NO_FALLBACK = 0x100,
/*
* BDRV_REQ_PREFETCH makes sense only in the context of copy-on-read
* (i.e., together with the BDRV_REQ_COPY_ON_READ flag or when a COR
* filter is involved), in which case it signals that the COR operation
* need not read the data into memory (qiov) but only ensure they are
* copied to the top layer (i.e., that COR operation is done).
*/
BDRV_REQ_PREFETCH = 0x200,
/*
* If we need to wait for other requests, just fail immediately. Used
* only together with BDRV_REQ_SERIALISING. Used only with requests aligned
* to request_alignment (corresponding assertions are in block/io.c).
*/
BDRV_REQ_NO_WAIT = 0x400,
/* Mask of valid flags */
BDRV_REQ_MASK = 0x7ff,
} BdrvRequestFlags;
#define BDRV_O_NO_SHARE 0x0001 /* don't share permissions */
#define BDRV_O_RDWR 0x0002
#define BDRV_O_RESIZE 0x0004 /* request permission for resizing the node */
#define BDRV_O_SNAPSHOT 0x0008 /* open the file read only and save
writes in a snapshot */
#define BDRV_O_TEMPORARY 0x0010 /* delete the file after use */
#define BDRV_O_NOCACHE 0x0020 /* do not use the host page cache */
#define BDRV_O_NATIVE_AIO 0x0080 /* use native AIO instead of the
thread pool */
#define BDRV_O_NO_BACKING 0x0100 /* don't open the backing file */
#define BDRV_O_NO_FLUSH 0x0200 /* disable flushing on this disk */
#define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
#define BDRV_O_INACTIVE 0x0800 /* consistency hint for migration handoff */
#define BDRV_O_CHECK 0x1000 /* open solely for consistency check */
#define BDRV_O_ALLOW_RDWR 0x2000 /* allow reopen to change from r/o to r/w */
#define BDRV_O_UNMAP 0x4000 /* execute guest UNMAP/TRIM operations */
#define BDRV_O_PROTOCOL 0x8000 /* if no block driver is explicitly given:
select an appropriate protocol driver,
ignoring the format layer */
#define BDRV_O_NO_IO 0x10000 /* don't initialize for I/O */
#define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening
read-write fails */
#define BDRV_O_IO_URING 0x40000 /* use io_uring instead of the thread pool */
#define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
/* Option names of options parsed by the block layer */
#define BDRV_OPT_CACHE_WB "cache.writeback"
#define BDRV_OPT_CACHE_DIRECT "cache.direct"
#define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
#define BDRV_OPT_READ_ONLY "read-only"
#define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
#define BDRV_OPT_DISCARD "discard"
#define BDRV_OPT_FORCE_SHARE "force-share"
#define BDRV_SECTOR_BITS 9
#define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
#define BDRV_REQUEST_MAX_SECTORS MIN_CONST(SIZE_MAX >> BDRV_SECTOR_BITS, \
INT_MAX >> BDRV_SECTOR_BITS)
#define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
/*
* We want allow aligning requests and disk length up to any 32bit alignment
* and don't afraid of overflow.
* To achieve it, and in the same time use some pretty number as maximum disk
* size, let's define maximum "length" (a limit for any offset/bytes request and
* for disk size) to be the greatest power of 2 less than INT64_MAX.
*/
#define BDRV_MAX_ALIGNMENT (1L << 30)
#define BDRV_MAX_LENGTH (QEMU_ALIGN_DOWN(INT64_MAX, BDRV_MAX_ALIGNMENT))
/*
* Allocation status flags for bdrv_block_status() and friends.
*
* Public flags:
* BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
* BDRV_BLOCK_ZERO: offset reads as zero
* BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
* BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
* layer rather than any backing, set by block layer
* BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
* layer, set by block layer
*
* Internal flags:
* BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
* that the block layer recompute the answer from the returned
* BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
* BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
* zeroes in file child of current block node inside
* returned region. Only valid together with both
* BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
* appear with BDRV_BLOCK_ZERO.
*
* If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
* host offset within the returned BDS that is allocated for the
* corresponding raw guest data. However, whether that offset
* actually contains data also depends on BDRV_BLOCK_DATA, as follows:
*
* DATA ZERO OFFSET_VALID
* t t t sectors read as zero, returned file is zero at offset
* t f t sectors read as valid from file at offset
* f t t sectors preallocated, read as zero, returned file not
* necessarily zero at offset
* f f t sectors preallocated but read from backing_hd,
* returned file contains garbage at offset
* t t f sectors preallocated, read as zero, unknown offset
* t f f sectors read from unknown file or offset
* f t f not allocated or unknown offset, read as zero
* f f f not allocated or unknown offset, read from backing_hd
*/
#define BDRV_BLOCK_DATA 0x01
#define BDRV_BLOCK_ZERO 0x02
#define BDRV_BLOCK_OFFSET_VALID 0x04
#define BDRV_BLOCK_RAW 0x08
#define BDRV_BLOCK_ALLOCATED 0x10
#define BDRV_BLOCK_EOF 0x20
#define BDRV_BLOCK_RECURSE 0x40
typedef QTAILQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
typedef struct BDRVReopenState {
BlockDriverState *bs;
int flags;
BlockdevDetectZeroesOptions detect_zeroes;
bool backing_missing;
BlockDriverState *old_backing_bs; /* keep pointer for permissions update */
BlockDriverState *old_file_bs; /* keep pointer for permissions update */
QDict *options;
QDict *explicit_options;
void *opaque;
} BDRVReopenState;
/*
* Block operation types
*/
typedef enum BlockOpType {
BLOCK_OP_TYPE_BACKUP_SOURCE,
BLOCK_OP_TYPE_BACKUP_TARGET,
BLOCK_OP_TYPE_CHANGE,
BLOCK_OP_TYPE_COMMIT_SOURCE,
BLOCK_OP_TYPE_COMMIT_TARGET,
BLOCK_OP_TYPE_DATAPLANE,
BLOCK_OP_TYPE_DRIVE_DEL,
BLOCK_OP_TYPE_EJECT,
BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
BLOCK_OP_TYPE_MIRROR_SOURCE,
BLOCK_OP_TYPE_MIRROR_TARGET,
BLOCK_OP_TYPE_RESIZE,
BLOCK_OP_TYPE_STREAM,
BLOCK_OP_TYPE_REPLACE,
BLOCK_OP_TYPE_MAX,
} BlockOpType;
/* Block node permission constants */
enum {
/**
* A user that has the "permission" of consistent reads is guaranteed that
* their view of the contents of the block device is complete and
* self-consistent, representing the contents of a disk at a specific
* point.
*
* For most block devices (including their backing files) this is true, but
* the property cannot be maintained in a few situations like for
* intermediate nodes of a commit block job.
*/
BLK_PERM_CONSISTENT_READ = 0x01,
/** This permission is required to change the visible disk contents. */
BLK_PERM_WRITE = 0x02,
/**
* This permission (which is weaker than BLK_PERM_WRITE) is both enough and
* required for writes to the block node when the caller promises that
* the visible disk content doesn't change.
*
* As the BLK_PERM_WRITE permission is strictly stronger, either is
* sufficient to perform an unchanging write.
*/
BLK_PERM_WRITE_UNCHANGED = 0x04,
/** This permission is required to change the size of a block node. */
BLK_PERM_RESIZE = 0x08,
/**
* There was a now-removed bit BLK_PERM_GRAPH_MOD, with value of 0x10. QEMU
* 6.1 and earlier may still lock the corresponding byte in block/file-posix
* locking. So, implementing some new permission should be very careful to
* not interfere with this old unused thing.
*/
BLK_PERM_ALL = 0x0f,
DEFAULT_PERM_PASSTHROUGH = BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_RESIZE,
DEFAULT_PERM_UNCHANGED = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
};
/*
* Flags that parent nodes assign to child nodes to specify what kind of
* role(s) they take.
*
* At least one of DATA, METADATA, FILTERED, or COW must be set for
* every child.
*/
enum BdrvChildRoleBits {
/*
* This child stores data.
* Any node may have an arbitrary number of such children.
*/
BDRV_CHILD_DATA = (1 << 0),
/*
* This child stores metadata.
* Any node may have an arbitrary number of metadata-storing
* children.
*/
BDRV_CHILD_METADATA = (1 << 1),
/*
* A child that always presents exactly the same visible data as
* the parent, e.g. by virtue of the parent forwarding all reads
* and writes.
* This flag is mutually exclusive with DATA, METADATA, and COW.
* Any node may have at most one filtered child at a time.
*/
BDRV_CHILD_FILTERED = (1 << 2),
/*
* Child from which to read all data that isn't allocated in the
* parent (i.e., the backing child); such data is copied to the
* parent through COW (and optionally COR).
* This field is mutually exclusive with DATA, METADATA, and
* FILTERED.
* Any node may have at most one such backing child at a time.
*/
BDRV_CHILD_COW = (1 << 3),
/*
* The primary child. For most drivers, this is the child whose
* filename applies best to the parent node.
* Any node may have at most one primary child at a time.
*/
BDRV_CHILD_PRIMARY = (1 << 4),
/* Useful combination of flags */
BDRV_CHILD_IMAGE = BDRV_CHILD_DATA
| BDRV_CHILD_METADATA
| BDRV_CHILD_PRIMARY,
};
/* Mask of BdrvChildRoleBits values */
typedef unsigned int BdrvChildRole;
typedef struct BdrvCheckResult {
int corruptions;
int leaks;
int check_errors;
int corruptions_fixed;
int leaks_fixed;
int64_t image_end_offset;
BlockFragInfo bfi;
} BdrvCheckResult;
typedef enum {
BDRV_FIX_LEAKS = 1,
BDRV_FIX_ERRORS = 2,
} BdrvCheckMode;
typedef struct BlockSizes {
uint32_t phys;
uint32_t log;
} BlockSizes;
typedef struct HDGeometry {
uint32_t heads;
uint32_t sectors;
uint32_t cylinders;
} HDGeometry;
/*
* Common functions that are neither I/O nor Global State.
*
* These functions must never call any function from other categories
* (I/O, "I/O or GS", Global State) except this one, but can be invoked by
* all of them.
*/
char *bdrv_perm_names(uint64_t perm);
uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
void bdrv_init_with_whitelist(void);
bool bdrv_uses_whitelist(void);
int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
int bdrv_parse_aio(const char *mode, int *flags);
int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
int bdrv_parse_discard_flags(const char *mode, int *flags);
int path_has_protocol(const char *path);
int path_is_absolute(const char *path);
char *path_combine(const char *base_path, const char *filename);
char *bdrv_get_full_backing_filename_from_filename(const char *backed,
const char *backing,
Error **errp);
#endif /* BLOCK_COMMON_H */
