/* * 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 "qemu/hbitmap.h" #include "qemu/transactions.h" /* * co_wrapper{*}: Function specifiers used by block-coroutine-wrapper.py * * Function specifiers, which do nothing but mark functions to be * generated by scripts/block-coroutine-wrapper.py * * Usage: read docs/devel/block-coroutine-wrapper.rst * * There are 2 kind of specifiers: * - co_wrapper functions can be called by only non-coroutine context, because * they always generate a new coroutine. * - co_wrapper_mixed functions can be called by both coroutine and * non-coroutine context. */ #define co_wrapper #define co_wrapper_mixed #include "block/dirty-bitmap.h" #include "block/blockjob.h" /* 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, /* * An optimization hint when all QEMUIOVector elements are within * previously registered bdrv_register_buf() memory ranges. * * Code that replaces the user's QEMUIOVector elements with bounce buffers * must take care to clear this flag. */ BDRV_REQ_REGISTERED_BUF = 0x8, 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. * * * = Connection with bs->children, bs->file and bs->backing fields = * * 1. Filters * * Filter drivers have drv->is_filter = true. * * Filter node has exactly one FILTERED|PRIMARY child, and may have other * children which must not have these bits (one example is the * copy-before-write filter, which also has its target DATA child). * * Filter nodes never have COW children. * * For most filters, the filtered child is linked in bs->file, bs->backing is * NULL. For some filters (as an exception), it is the other way around; those * drivers will have drv->filtered_child_is_backing set to true (see that * field’s documentation for what drivers this concerns) * * 2. "raw" driver (block/raw-format.c) * * Formally it's not a filter (drv->is_filter = false) * * bs->backing is always NULL * * Only has one child, linked in bs->file. Its role is either FILTERED|PRIMARY * (like filter) or DATA|PRIMARY depending on options. * * 3. Other drivers * * Don't have any FILTERED children. * * May have at most one COW child. In this case it's linked in bs->backing. * Otherwise bs->backing is NULL. COW child is never PRIMARY. * * May have at most one PRIMARY child. In this case it's linked in bs->file. * Otherwise bs->file is NULL. * * May also have some other children that don't have the PRIMARY or COW bit set. */ 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 */