Commit b9f66d96 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

blkdebug: Inject errors 



Add a mechanism to inject errors instead of passing requests on. With no
further patches applied, you can use it by setting inject_errno in gdb.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 6a143727

block/blkdebug.c

+81 −0
Original line number Diff line number Diff line
@@ -26,10 +26,41 @@ 
#include "block_int.h"

#include "module.h"



#include <stdbool.h>



typedef struct BlkdebugVars {

    int state;



    /* If inject_errno != 0, an error is injected for requests */

    int inject_errno;



    /* Decides if all future requests fail (false) or only the next one and

     * after the next request inject_errno is reset to 0 (true) */

    bool inject_once;



    /* Decides if aio_readv/writev fails right away (true) or returns an error

     * return value only in the callback (false) */

    bool inject_immediately;

} BlkdebugVars;



typedef struct BDRVBlkdebugState {

    BlockDriverState *hd;

    BlkdebugVars vars;

} BDRVBlkdebugState;



typedef struct BlkdebugAIOCB {

    BlockDriverAIOCB common;

    QEMUBH *bh;

    int ret;

} BlkdebugAIOCB;



static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);



static AIOPool blkdebug_aio_pool = {

    .aiocb_size = sizeof(BlkdebugAIOCB),

    .cancel     = blkdebug_aio_cancel,

};



static int blkdebug_open(BlockDriverState *bs, const char *filename, int flags)

{

    BDRVBlkdebugState *s = bs->opaque;
@@ -42,11 +73,56 @@ static int blkdebug_open(BlockDriverState *bs, const char *filename, int flags) 
    return bdrv_file_open(&s->hd, filename, flags);

}



static void error_callback_bh(void *opaque)

{

    struct BlkdebugAIOCB *acb = opaque;

    qemu_bh_delete(acb->bh);

    acb->common.cb(acb->common.opaque, acb->ret);

    qemu_aio_release(acb);

}



static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)

{

    BlkdebugAIOCB *acb = (BlkdebugAIOCB*) blockacb;

    qemu_aio_release(acb);

}



static BlockDriverAIOCB *inject_error(BlockDriverState *bs,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;

    int error = s->vars.inject_errno;

    struct BlkdebugAIOCB *acb;

    QEMUBH *bh;



    if (s->vars.inject_once) {

        s->vars.inject_errno = 0;

    }



    if (s->vars.inject_immediately) {

        return NULL;

    }



    acb = qemu_aio_get(&blkdebug_aio_pool, bs, cb, opaque);

    acb->ret = -error;



    bh = qemu_bh_new(error_callback_bh, acb);

    acb->bh = bh;

    qemu_bh_schedule(bh);



    return (BlockDriverAIOCB*) acb;

}



static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,

    int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;



    if (s->vars.inject_errno) {

        return inject_error(bs, cb, opaque);

    }



    BlockDriverAIOCB *acb =

        bdrv_aio_readv(s->hd, sector_num, qiov, nb_sectors, cb, opaque);

    return acb;
@@ -57,6 +133,11 @@ static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs, 
    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;



    if (s->vars.inject_errno) {

        return inject_error(bs, cb, opaque);

    }



    BlockDriverAIOCB *acb =

        bdrv_aio_writev(s->hd, sector_num, qiov, nb_sectors, cb, opaque);

    return acb;