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    block_int.h 15.60 KiB
    /*
     * 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.h"
    #include "qemu-option.h"
    #include "qemu-queue.h"
    #include "qemu-coroutine.h"
    #include "qemu-timer.h"
    #include "qapi-types.h"
    
    #define BLOCK_FLAG_ENCRYPT	1
    #define BLOCK_FLAG_COMPAT6	4
    
    #define BLOCK_IO_LIMIT_READ     0
    #define BLOCK_IO_LIMIT_WRITE    1
    #define BLOCK_IO_LIMIT_TOTAL    2
    
    #define BLOCK_IO_SLICE_TIME     100000000
    #define NANOSECONDS_PER_SECOND  1000000000.0
    
    #define BLOCK_OPT_SIZE          "size"
    #define BLOCK_OPT_ENCRYPT       "encryption"
    #define BLOCK_OPT_COMPAT6       "compat6"
    #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"
    
    typedef struct BdrvTrackedRequest BdrvTrackedRequest;
    
    typedef struct BlockIOLimit {
        int64_t bps[3];
        int64_t iops[3];
    } BlockIOLimit;
    
    typedef struct BlockIOBaseValue {
        uint64_t bytes[2];
        uint64_t ios[2];
    } BlockIOBaseValue;
    
    typedef struct BlockJob BlockJob;
    
    /**
     * BlockJobType:
     *
     * A class type for block job objects.
     */
    typedef struct BlockJobType {
        /** Derived BlockJob struct size */
        size_t instance_size;
    
        /** String describing the operation, part of query-block-jobs QMP API */
        const char *job_type;
    
        /** Optional callback for job types that support setting a speed limit */
        void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
    } BlockJobType;
    
    /**
     * BlockJob:
     *
     * Long-running operation on a BlockDriverState.
     */
    struct BlockJob {
        /** The job type, including the job vtable.  */
        const BlockJobType *job_type;
    
        /** The block device on which the job is operating.  */
        BlockDriverState *bs;
    
        /**
         * Set to true if the job should cancel itself.  The flag must
         * always be tested just before toggling the busy flag from false
         * to true.  After a job has detected that the cancelled flag is
         * true, it should not anymore issue any I/O operation to the
         * block device.
         */
        bool cancelled;
    
        /**
         * Set to false by the job while it is in a quiescent state, where
         * no I/O is pending and cancellation can be processed without
         * issuing new I/O.  The busy flag must be set to false when the
         * job goes to sleep on any condition that is not detected by
         * #qemu_aio_wait, such as a timer.
         */
        bool busy;
    
        /** Offset that is published by the query-block-jobs QMP API */
        int64_t offset;
    
        /** Length that is published by the query-block-jobs QMP API */
        int64_t len;
    
        /** Speed that was set with @block_job_set_speed.  */
        int64_t speed;
    
        /** The completion function that will be called when the job completes.  */
        BlockDriverCompletionFunc *cb;
    
        /** The opaque value that is passed to the completion function.  */
        void *opaque;
    };
    
    struct BlockDriver {
        const char *format_name;
        int instance_size;
        int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
        int (*bdrv_probe_device)(const char *filename);
        int (*bdrv_open)(BlockDriverState *bs, int flags);
        int (*bdrv_file_open)(BlockDriverState *bs, const char *filename, int flags);
        int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
                         uint8_t *buf, int nb_sectors);
        int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
                          const uint8_t *buf, int nb_sectors);
        void (*bdrv_close)(BlockDriverState *bs);
        int (*bdrv_create)(const char *filename, QEMUOptionParameter *options);
        int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
        int (*bdrv_make_empty)(BlockDriverState *bs);
        /* aio */
        BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
            int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
            BlockDriverCompletionFunc *cb, void *opaque);
        BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
            int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
            BlockDriverCompletionFunc *cb, void *opaque);
        BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
            BlockDriverCompletionFunc *cb, void *opaque);
        BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
            int64_t sector_num, int nb_sectors,
            BlockDriverCompletionFunc *cb, void *opaque);
    
        int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
            int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
        int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
            int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
        /*
         * 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 and .bdrv_co_writev() will be called
         * instead.
         */
        int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
            int64_t sector_num, int nb_sectors);
        int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
            int64_t sector_num, int nb_sectors);
        int coroutine_fn (*bdrv_co_is_allocated)(BlockDriverState *bs,
            int64_t sector_num, int nb_sectors, int *pnum);
    
        /*
         * Invalidate any cached meta-data.
         */
        void (*bdrv_invalidate_cache)(BlockDriverState *bs);
    
        /*
         * Flushes all data that was already written to the OS all the way down to
         * the disk (for example raw-posix calls fsync()).
         */
        int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
    
        /*
         * Flushes all internal caches to the OS. The data may still sit in a
         * writeback cache of the host OS, but it will survive a crash of the qemu
         * process.
         */
        int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
    
        const char *protocol_name;
        int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
        int64_t (*bdrv_getlength)(BlockDriverState *bs);
        int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
        int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
                                     const uint8_t *buf, int nb_sectors);
    
        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);
        int (*bdrv_snapshot_list)(BlockDriverState *bs,
                                  QEMUSnapshotInfo **psn_info);
        int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
                                      const char *snapshot_name);
        int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
    
        int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
                                 int64_t pos, int size);
        int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
                                 int64_t pos, int size);
    
        int (*bdrv_change_backing_file)(BlockDriverState *bs,
            const char *backing_file, const char *backing_fmt);
    
        /* removable device specific */
        int (*bdrv_is_inserted)(BlockDriverState *bs);
        int (*bdrv_media_changed)(BlockDriverState *bs);
        void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
        void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
    
        /* to control generic scsi devices */
        int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
        BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
            unsigned long int req, void *buf,
            BlockDriverCompletionFunc *cb, void *opaque);
    
        /* List of options for creating images, terminated by name == NULL */
        QEMUOptionParameter *create_options;
    
    
        /*
         * Returns 0 for completed check, -errno for internal errors.
         * The check results are stored in result.
         */
        int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result);
    
        void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
    
        /*
         * Returns 1 if newly created images are guaranteed to contain only
         * zeros, 0 otherwise.
         */
        int (*bdrv_has_zero_init)(BlockDriverState *bs);
    
        QLIST_ENTRY(BlockDriver) list;
    };
    
    /*
     * 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 {
        int64_t total_sectors; /* if we are reading a disk image, give its
                                  size in sectors */
        int read_only; /* if true, the media is read only */
        int keep_read_only; /* if true, the media was requested to stay read only */
        int open_flags; /* flags used to open the file, re-used for re-open */
        int encrypted; /* if true, the media is encrypted */
        int valid_key; /* if true, a valid encryption key has been set */
        int sg;        /* if true, the device is a /dev/sg* */
        int copy_on_read; /* if true, copy read backing sectors into image
                             note this is a reference count */
    
        BlockDriver *drv; /* NULL means no media */
        void *opaque;
    
        void *dev;                  /* attached device model, if any */
        /* TODO change to DeviceState when all users are qdevified */
        const BlockDevOps *dev_ops;
        void *dev_opaque;
    
        char filename[1024];
        char backing_file[1024]; /* if non zero, the image is a diff of
                                    this file image */
        char backing_format[16]; /* if non-zero and backing_file exists */
        int is_temporary;
    
        BlockDriverState *backing_hd;
        BlockDriverState *file;
    
        /* number of in-flight copy-on-read requests */
        unsigned int copy_on_read_in_flight;
    
        /* the time for latest disk I/O */
        int64_t slice_time;
        int64_t slice_start;
        int64_t slice_end;
        BlockIOLimit io_limits;
        BlockIOBaseValue  io_base;
        CoQueue      throttled_reqs;
        QEMUTimer    *block_timer;
        bool         io_limits_enabled;
    
        /* I/O stats (display with "info blockstats"). */
        uint64_t nr_bytes[BDRV_MAX_IOTYPE];
        uint64_t nr_ops[BDRV_MAX_IOTYPE];
        uint64_t total_time_ns[BDRV_MAX_IOTYPE];
        uint64_t wr_highest_sector;
    
        /* Whether the disk can expand beyond total_sectors */
        int growable;
    
        /* the memory alignment required for the buffers handled by this driver */
        int buffer_alignment;
    
        /* do we need to tell the quest if we have a volatile write cache? */
        int enable_write_cache;
    
        /* NOTE: the following infos are only hints for real hardware
           drivers. They are not used by the block driver */
        int cyls, heads, secs, translation;
        BlockErrorAction on_read_error, on_write_error;
        bool iostatus_enabled;
        BlockDeviceIoStatus iostatus;
        char device_name[32];
        unsigned long *dirty_bitmap;
        int64_t dirty_count;
        int in_use; /* users other than guest access, eg. block migration */
        QTAILQ_ENTRY(BlockDriverState) list;
    
        QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
    
        /* long-running background operation */
        BlockJob *job;
    };
    
    void get_tmp_filename(char *filename, int size);
    
    void bdrv_set_io_limits(BlockDriverState *bs,
                            BlockIOLimit *io_limits);
    
    #ifdef _WIN32
    int is_windows_drive(const char *filename);
    #endif
    
    /**
     * block_job_create:
     * @job_type: The class object for the newly-created job.
     * @bs: The block
     * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
     * @cb: Completion function for the job.
     * @opaque: Opaque pointer value passed to @cb.
     * @errp: Error object.
     *
     * Create a new long-running block device job and return it.  The job
     * will call @cb asynchronously when the job completes.  Note that
     * @bs may have been closed at the time the @cb it is called.  If
     * this is the case, the job may be reported as either cancelled or
     * completed.
     *
     * This function is not part of the public job interface; it should be
     * called from a wrapper that is specific to the job type.
     */
    void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
                           int64_t speed, BlockDriverCompletionFunc *cb,
                           void *opaque, Error **errp);
    
    /**
     * block_job_complete:
     * @job: The job being completed.
     * @ret: The status code.
     *
     * Call the completion function that was registered at creation time, and
     * free @job.
     */
    void block_job_complete(BlockJob *job, int ret);
    
    /**
     * block_job_set_speed:
     * @job: The job to set the speed for.
     * @speed: The new value
     * @errp: Error object.
     *
     * Set a rate-limiting parameter for the job; the actual meaning may
     * vary depending on the job type.
     */
    void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
    
    /**
     * block_job_cancel:
     * @job: The job to be canceled.
     *
     * Asynchronously cancel the specified job.
     */
    void block_job_cancel(BlockJob *job);
    
    /**
     * block_job_is_cancelled:
     * @job: The job being queried.
     *
     * Returns whether the job is scheduled for cancellation.
     */
    bool block_job_is_cancelled(BlockJob *job);
    
    /**
     * block_job_cancel:
     * @job: The job to be canceled.
     *
     * Asynchronously cancel the job and wait for it to reach a quiescent
     * state.  Note that the completion callback will still be called
     * asynchronously, hence it is *not* valid to call #bdrv_delete
     * immediately after #block_job_cancel_sync.  Users of block jobs
     * will usually protect the BlockDriverState objects with a reference
     * count, should this be a concern.
     */
    void block_job_cancel_sync(BlockJob *job);
    
    /**
     * stream_start:
     * @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.
     * @base_id: The file name that will be written to @bs as the new
     * backing file if the job completes.  Ignored if @base is %NULL.
     * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
     * @cb: Completion function for the job.
     * @opaque: Opaque pointer value passed to @cb.
     * @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
     * @base_id in the written image and to @base in the live BlockDriverState.
     */
    void stream_start(BlockDriverState *bs, BlockDriverState *base,
                      const char *base_id, int64_t speed,
                      BlockDriverCompletionFunc *cb,
                      void *opaque, Error **errp);
    
    #endif /* BLOCK_INT_H */