Commit 18930ba3 authored by Fam Zheng's avatar Fam Zheng Committed by Kevin Wolf
Browse files

blockjob: Introduce reference count and fix reference to job->bs 



Add reference count to block job, meanwhile move the ownership of the
reference to job->bs from the caller (which is released in two
completion callbacks) to the block job itself. It is necessary for
block_job_complete_sync to work, because block job shouldn't live longer
than its bs, as asserted in bdrv_delete.

Now block_job_complete_sync can be simplified.

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarJohn Snow <jsnow@redhat.com>
Message-id: 1446765200-3054-6-git-send-email-jsnow@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent b976ea3c

block/mirror.c

+1 −1
Original line number Diff line number Diff line
@@ -742,7 +742,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, 
    s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);

    if (!s->dirty_bitmap) {

        g_free(s->replaces);

        block_job_release(bs);

        block_job_unref(&s->common);

        return;

    }

blockdev.c

+0 −28
Original line number Diff line number Diff line
@@ -283,32 +283,6 @@ typedef struct { 
    BlockDriverState *bs;

} BDRVPutRefBH;



static void bdrv_put_ref_bh(void *opaque)

{

    BDRVPutRefBH *s = opaque;



    bdrv_unref(s->bs);

    qemu_bh_delete(s->bh);

    g_free(s);

}



/*

 * Release a BDS reference in a BH

 *

 * It is not safe to use bdrv_unref() from a callback function when the callers

 * still need the BlockDriverState.  In such cases we schedule a BH to release

 * the reference.

 */

static void bdrv_put_ref_bh_schedule(BlockDriverState *bs)

{

    BDRVPutRefBH *s;



    s = g_new(BDRVPutRefBH, 1);

    s->bh = qemu_bh_new(bdrv_put_ref_bh, s);

    s->bs = bs;

    qemu_bh_schedule(s->bh);

}



static int parse_block_error_action(const char *buf, bool is_read, Error **errp)

{

    if (!strcmp(buf, "ignore")) {
@@ -2741,8 +2715,6 @@ static void block_job_cb(void *opaque, int ret) 
    } else {

        block_job_event_completed(bs->job, msg);

    }



    bdrv_put_ref_bh_schedule(bs);

}



void qmp_block_stream(const char *device,

blockjob.c

+16 −9
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, 
    job->cb            = cb;

    job->opaque        = opaque;

    job->busy          = true;

    job->refcnt        = 1;

    bs->job = job;



    /* Only set speed when necessary to avoid NotSupported error */
@@ -68,7 +69,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, 


        block_job_set_speed(job, speed, &local_err);

        if (local_err) {

            block_job_release(bs);

            block_job_unref(job);

            error_propagate(errp, local_err);

            return NULL;

        }
@@ -76,16 +77,22 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, 
    return job;

}



void block_job_release(BlockDriverState *bs)

void block_job_ref(BlockJob *job)

{

    BlockJob *job = bs->job;

    ++job->refcnt;

}



    bs->job = NULL;

    bdrv_op_unblock_all(bs, job->blocker);

void block_job_unref(BlockJob *job)

{

    if (--job->refcnt == 0) {

        job->bs->job = NULL;

        bdrv_op_unblock_all(job->bs, job->blocker);

        bdrv_unref(job->bs);

        error_free(job->blocker);

        g_free(job->id);

        g_free(job);

    }

}



void block_job_completed(BlockJob *job, int ret)

{
@@ -93,7 +100,7 @@ void block_job_completed(BlockJob *job, int ret) 


    assert(bs->job == job);

    job->cb(job->opaque, ret);

    block_job_release(bs);

    block_job_unref(job);

}



void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)

include/block/blockjob.h

+15 −3
Original line number Diff line number Diff line
@@ -130,6 +130,9 @@ struct BlockJob { 


    /** The opaque value that is passed to the completion function.  */

    void *opaque;



    /** Reference count of the block job */

    int refcnt;

};



/**
@@ -174,12 +177,21 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns); 
void block_job_yield(BlockJob *job);



/**

 * block_job_release:

 * block_job_ref:

 * @bs: The block device.

 *

 * Grab a reference to the block job. Should be paired with block_job_unref.

 */

void block_job_ref(BlockJob *job);



/**

 * block_job_unref:

 * @bs: The block device.

 *

 * Release job resources when an error occurred or job completed.

 * Release reference to the block job and release resources if it is the last

 * reference.

 */

void block_job_release(BlockDriverState *bs);

void block_job_unref(BlockJob *job);



/**

 * block_job_completed:

qemu-img.c

+0 −3
Original line number Diff line number Diff line
@@ -645,9 +645,6 @@ static void common_block_job_cb(void *opaque, int ret) 
    if (ret < 0) {

        error_setg_errno(cbi->errp, -ret, "Block job failed");

    }



    /* Drop this block job's reference */

    bdrv_unref(cbi->bs);

}



static void run_block_job(BlockJob *job, Error **errp)