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Diffstat (limited to 'include/block/block_int-common.h')
| -rw-r--r-- | include/block/block_int-common.h | 1222 |
1 files changed, 1222 insertions, 0 deletions
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h new file mode 100644 index 0000000000..5a04c778e4 --- /dev/null +++ b/include/block/block_int-common.h @@ -0,0 +1,1222 @@ +/* + * 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_COMMON_H +#define BLOCK_INT_COMMON_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" +#include "qemu/rcu.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, +}; + +/* + * That is not quite good that BdrvTrackedRequest structure is public, + * as block/io.c is very careful about incoming offset/bytes being + * correct. Be sure to assert bdrv_check_request() succeeded after any + * modification of BdrvTrackedRequest object out of block/io.c + */ +typedef struct BdrvTrackedRequest { + BlockDriverState *bs; + int64_t offset; + int64_t bytes; + enum BdrvTrackedRequestType type; + + bool serialising; + int64_t overlap_offset; + int64_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 { + /* + * These fields are initialized when this object is created, + * and are never changed afterwards. + */ + + 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; + + /* + * 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; + + bool has_variable_length; + + /* + * 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; + + /* 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; + + /* + * 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; + + + /* + * Global state (GS) API. These functions run under the BQL. + * + * See include/block/block-global-state.h for more information about + * the GS API. + */ + + /* + * This function is invoked under BQL before .bdrv_co_amend() + * (which in contrast does not necessarily run under the BQL) + * to allow driver-specific initialization code that requires + * the BQL, like setting up specific permission flags. + */ + int (*bdrv_amend_pre_run)(BlockDriverState *bs, Error **errp); + /* + * This function is invoked under BQL after .bdrv_co_amend() + * to allow cleaning up what was done in .bdrv_amend_pre_run(). + */ + void (*bdrv_amend_clean)(BlockDriverState *bs); + + /* + * 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_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); + + /* 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 (*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); + + /* + * This informs the driver that we are no longer interested in the result + * of in-flight requests, so don't waste the time if possible. + * + * One example usage is to avoid waiting for an nbd target node reconnect + * timeout during job-cancel with force=true. + */ + void (*bdrv_cancel_in_flight)(BlockDriverState *bs); + + int (*bdrv_inactivate)(BlockDriverState *bs); + + 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_change_backing_file)(BlockDriverState *bs, + const char *backing_file, const char *backing_fmt); + + /* 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); + + /** + * 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); + + 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); + + /** + * 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); + + /* + * This field is modified only under the BQL, and is part of + * the global state. + */ + QLIST_ENTRY(BlockDriver) list; + + /* + * I/O API functions. These functions are thread-safe. + * + * See include/block/block-io.h for more information about + * the I/O API. + */ + + int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); + + int coroutine_fn (*bdrv_co_amend)(BlockDriverState *bs, + BlockdevAmendOptions *opts, + bool force, + Error **errp); + + /* aio */ + BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, + int64_t offset, int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); + BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs, + int64_t offset, int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags 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, + int64_t offset, int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags); + + int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, + int64_t offset, int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, + BdrvRequestFlags 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, + int64_t offset, int64_t bytes, QEMUIOVector *qiov, + BdrvRequestFlags flags); + int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs, + int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, + BdrvRequestFlags 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, int64_t bytes, BdrvRequestFlags flags); + int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, + int64_t offset, int64_t 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, + int64_t offset, + BdrvChild *dst, + int64_t dst_offset, + int64_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, + int64_t src_offset, + BdrvChild *dst, + int64_t dst_offset, + int64_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. + * + * Note that @bytes is just a hint on how big of a region the + * caller wants to inspect. It is not a limit on *pnum. + * Implementations are free to return larger values of *pnum if + * doing so does not incur a performance penalty. + * + * block/io.c's bdrv_co_block_status() will utilize an unclamped + * *pnum value for the block-status cache on protocol nodes, prior + * to clamping *pnum for return to its caller. + */ + 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); + + /* + * 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); + + /* + * 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); + 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, + int64_t offset, int64_t bytes, QEMUIOVector *qiov); + int coroutine_fn (*bdrv_co_pwritev_compressed_part)(BlockDriverState *bs, + int64_t offset, int64_t bytes, QEMUIOVector *qiov, + size_t qiov_offset); + + 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); + + /* 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); + + /* + * 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); + + /* io queue for linux-aio */ + void (*bdrv_io_plug)(BlockDriverState *bs); + void (*bdrv_io_unplug)(BlockDriverState *bs); + + /** + * 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); + + 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); +}; + +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. Must be multiple + * of pdiscard_alignment, but need not be power of 2. May be 0 if no + * inherent 64-bit limit. + */ + int64_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. Must be multiple of + * pwrite_zeroes_alignment. 0 means no limit. + */ + int64_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; + + /* + * Maximal hardware transfer length in bytes. Applies whenever + * transfers to the device bypass the kernel I/O scheduler, for + * example with SG_IO. If larger than max_transfer or if zero, + * blk_get_max_hw_transfer will fall back to max_transfer. + */ + uint64_t max_hw_transfer; + + /* + * Maximal number of scatter/gather elements allowed by the hardware. + * Applies whenever transfers to the device bypass the kernel I/O + * scheduler, for example with SG_IO. If larger than max_iov + * or if zero, blk_get_max_hw_iov will fall back to max_iov. + */ + int max_hw_iov; + + + /* 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; + + /* + * Global state (GS) API. These functions run under the BQL. + * + * See include/block/block-global-state.h for more information about + * the GS API. + */ + 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); + + /* + * 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); + + /* + * 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); + + AioContext *(*get_parent_aio_context)(BdrvChild *child); + + /* + * I/O API functions. These functions are thread-safe. + * + * See include/block/block-io.h for more information about + * the I/O API. + */ + + 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); + + /* + * 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); +}; + +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; + + /* + * 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; +}; + +/* + * Allows bdrv_co_block_status() to cache one data region for a + * protocol node. + * + * @valid: Whether the cache is valid (should be accessed with atomic + * functions so this can be reset by RCU readers) + * @data_start: Offset where we know (or strongly assume) is data + * @data_end: Offset where the data region ends (which is not necessarily + * the start of a zeroed region) + */ +typedef struct BdrvBlockStatusCache { + struct rcu_head rcu; + + bool valid; + int64_t data_start; + int64_t data_end; +} BdrvBlockStatusCache; + +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 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 pread + */ + unsigned int supported_read_flags; + /* + * 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. Protected by BQL. */ + 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; + + /* threshold limit for writes, in bytes. "High water mark". */ + uint64_t write_threshold_offset; + + /* + * 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; + + /* Lock for block-status cache RCU writers */ + CoMutex bsc_modify_lock; + /* Always non-NULL, but must only be dereferenced under an RCU read guard */ + BdrvBlockStatusCache *block_status_cache; +}; + +struct BlockBackendRootState { + int open_flags; + 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; + +extern unsigned int bdrv_drain_all_count; +extern QemuOptsList bdrv_create_opts_simple; + +/* + * Common functions that are neither I/O nor Global State. + * + * See include/block/block-commmon.h for more information about + * the Common API. + */ + +static inline BlockDriverState *child_bs(BdrvChild *child) +{ + return child ? child->bs : NULL; +} + +int bdrv_check_request(int64_t offset, int64_t bytes, Error **errp); +int get_tmp_filename(char *filename, int size); +void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, + QDict *options); + + +int bdrv_check_qiov_request(int64_t offset, int64_t bytes, + QEMUIOVector *qiov, size_t qiov_offset, + Error **errp); + +#ifdef _WIN32 +int is_windows_drive(const char *filename); +#endif + +#endif /* BLOCK_INT_COMMON_H */ |