Commit 91bcea48 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

block: document fields protected by AioContext lock 



Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-19-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent bd451435

include/block/block_int.h

+39 −25
Original line number Diff line number Diff line
@@ -430,8 +430,9 @@ struct BdrvChild { 
 * copied as well.

 */

struct BlockDriverState {

    int64_t total_sectors; /* if we are reading a disk image, give its

                              size in sectors */

    /* 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 */
@@ -439,14 +440,6 @@ struct BlockDriverState { 
    bool sg;        /* if true, the device is a /dev/sg* */

    bool probed;    /* if true, format was probed rather than specified */



    int copy_on_read; /* if nonzero, copy read backing sectors into image.

                         note this is a reference count */



    CoQueue flush_queue;            /* Serializing flush queue */

    bool active_flush_req;          /* Flush request in flight? */

    unsigned int write_gen;         /* Current data generation */

    unsigned int flushed_gen;       /* Flushed write generation */



    BlockDriver *drv; /* NULL means no media */

    void *opaque;
@@ -468,18 +461,6 @@ struct BlockDriverState { 
    BdrvChild *backing;

    BdrvChild *file;



    /* Callback before write request is processed */

    NotifierWithReturnList before_write_notifiers;



    /* number of in-flight requests; overall and serialising */

    unsigned int in_flight;

    unsigned int serialising_in_flight;



    bool wakeup;



    /* Offset after the highest byte written to */

    uint64_t wr_highest_offset;



    /* I/O Limits */

    BlockLimits bl;
@@ -497,11 +478,8 @@ struct BlockDriverState { 
    QTAILQ_ENTRY(BlockDriverState) bs_list;

    /* element of the list of monitor-owned BDS */

    QTAILQ_ENTRY(BlockDriverState) monitor_list;

    QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;

    int refcnt;



    QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;



    /* operation blockers */

    QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
@@ -522,6 +500,31 @@ struct BlockDriverState { 
    /* The error object in use for blocking operations on backing_hd */

    Error *backing_blocker;



    /* Protected by AioContext lock */



    /* If true, copy read backing sectors into image.  Can be >1 if more

     * than one client has requested copy-on-read.

     */

    int copy_on_read;



    /* If we are reading a disk image, give its size in sectors.

     * Generally read-only; it is written to by load_vmstate and save_vmstate,

     * but the block layer is quiescent during those.

     */

    int64_t total_sectors;



    /* Callback before write request is processed */

    NotifierWithReturnList before_write_notifiers;



    /* number of in-flight requests; overall and serialising */

    unsigned int in_flight;

    unsigned int serialising_in_flight;



    bool wakeup;



    /* Offset after the highest byte written to */

    uint64_t wr_highest_offset;



    /* threshold limit for writes, in bytes. "High water mark". */

    uint64_t write_threshold_offset;

    NotifierWithReturn write_threshold_notifier;
@@ -529,6 +532,17 @@ struct BlockDriverState { 
    /* counter for nested bdrv_io_plug */

    unsigned io_plugged;



    QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;

    CoQueue flush_queue;                  /* Serializing flush queue */

    bool active_flush_req;                /* Flush request in flight? */

    unsigned int write_gen;               /* Current data generation */

    unsigned int flushed_gen;             /* Flushed write generation */



    QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;



    /* do we need to tell the quest if we have a volatile write cache? */

    int enable_write_cache;



    int quiesce_counter;

};

include/sysemu/block-backend.h

+10 −4
Original line number Diff line number Diff line
@@ -64,14 +64,20 @@ typedef struct BlockDevOps { 
 * fields that must be public. This is in particular for QLIST_ENTRY() and

 * friends so that BlockBackends can be kept in lists outside block-backend.c */

typedef struct BlockBackendPublic {

    /* I/O throttling.

     * throttle_state tells us if this BlockBackend has I/O limits configured.

     * io_limits_disabled tells us if they are currently being enforced */

    /* I/O throttling has its own locking, but also some fields are

     * protected by the AioContext lock.

     */



    /* Protected by AioContext lock.  */

    CoQueue      throttled_reqs[2];



    /* Nonzero if the I/O limits are currently being ignored; generally

     * it is zero.  */

    unsigned int io_limits_disabled;



    /* The following fields are protected by the ThrottleGroup lock.

     * See the ThrottleGroup documentation for details. */

     * See the ThrottleGroup documentation for details.

     * throttle_state tells us if I/O limits are configured. */

    ThrottleState *throttle_state;

    ThrottleTimers throttle_timers;

    unsigned       pending_reqs[2];