On Tue, May 24, 2011 at 12:31 AM, Marcelo Tosatti <mtosa...@redhat.com> wrote: > Mirrored writes are used by live block copy. > > Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com> > > Index: qemu-block-copy/block/blkmirror.c > =================================================================== > --- /dev/null > +++ qemu-block-copy/block/blkmirror.c > @@ -0,0 +1,239 @@ > +/* > + * Block driver for mirrored writes. > + * > + * Copyright (C) 2011 Red Hat, Inc. > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + */ > + > +#include <stdarg.h> > +#include "block_int.h" > + > +typedef struct { > + BlockDriverState *bs[2]; > +} BdrvMirrorState; > + > +/* Valid blkmirror filenames look like > blkmirror:path/to/image1:path/to/image2 */ > +static int blkmirror_open(BlockDriverState *bs, const char *filename, int > flags) > +{ > + BdrvMirrorState *m = bs->opaque; > + int ret; > + char *raw, *c; > + > + /* Parse the blkmirror: prefix */ > + if (strncmp(filename, "blkmirror:", strlen("blkmirror:"))) { > + return -EINVAL; > + } > + filename += strlen("blkmirror:"); > + > + /* Parse the raw image filename */ > + c = strchr(filename, ':'); > + if (c == NULL) { > + return -EINVAL; > + } > + > + raw = strdup(filename); > + raw[c - filename] = '\0'; > + ret = bdrv_file_open(&m->bs[0], raw, flags); > + free(raw); > + if (ret < 0) { > + return ret; > + } > + filename = c + 1; > + > + ret = bdrv_file_open(&m->bs[1], filename, flags); > + if (ret < 0) { > + bdrv_delete(m->bs[0]); > + return ret; > + } > + > + return 0; > +} > + > +static void blkmirror_close(BlockDriverState *bs) > +{ > + BdrvMirrorState *m = bs->opaque; > + int i; > + > + for (i=0; i<2; i++) { > + bdrv_delete(m->bs[i]); > + m->bs[i] = NULL; > + } > +} > + > +static int blkmirror_flush(BlockDriverState *bs) > +{ > + BdrvMirrorState *m = bs->opaque; > + > + bdrv_flush(m->bs[0]); > + bdrv_flush(m->bs[1]); > + > + return 0; > +} > + > +static int64_t blkmirror_getlength(BlockDriverState *bs) > +{ > + BdrvMirrorState *m = bs->opaque; > + > + return bdrv_getlength(m->bs[0]); > +} > + > +static BlockDriverAIOCB *blkmirror_aio_readv(BlockDriverState *bs, > + int64_t sector_num, > + QEMUIOVector *qiov, > + int nb_sectors, > + BlockDriverCompletionFunc *cb, > + void *opaque) > +{ > + BdrvMirrorState *m = bs->opaque; > + return bdrv_aio_readv(m->bs[0], sector_num, qiov, nb_sectors, cb, > opaque); > +} > + > +typedef struct DupAIOCB { > + BlockDriverAIOCB common; > + int count; > + > + BlockDriverCompletionFunc *cb; > + void *opaque; > + > + BlockDriverAIOCB *src_aiocb; > + BlockDriverAIOCB *dest_aiocb; > + > + int ret; > +} DupAIOCB;
Usually all types are defined at the top of the file. > + > +static void dup_aio_cancel(BlockDriverAIOCB *blockacb) > +{ > + DupAIOCB *acb = container_of(blockacb, DupAIOCB, common); > + > + bdrv_aio_cancel(acb->src_aiocb); > + bdrv_aio_cancel(acb->dest_aiocb); > + qemu_aio_release(acb); > +} > + > +static AIOPool dup_aio_pool = { > + .aiocb_size = sizeof(DupAIOCB), > + .cancel = dup_aio_cancel, > +}; > + > +static void blkmirror_aio_cb(void *opaque, int ret) > +{ > + DupAIOCB *dcb = opaque; > + > + dcb->count--; > + assert(dcb->count >= 0); > + if (dcb->count == 0) { > + if (dcb->ret < 0) { > + ret = dcb->ret; > + } > + dcb->common.cb(dcb->opaque, ret); > + qemu_aio_release(dcb); > + } > + dcb->ret = ret; > +} > + > +static DupAIOCB *dup_aio_get(BlockDriverState *bs, > + BlockDriverCompletionFunc *cb, > + void *opaque) > +{ > + DupAIOCB *dcb; > + > + dcb = qemu_aio_get(&dup_aio_pool, bs, cb, opaque); > + if (!dcb) > + return NULL; Please use QEMU's scripts/checkpatch.pl. > + dcb->count = 2; > + dcb->ret = 0; > + dcb->opaque = opaque; > + > + return dcb; > +} > + > +static BlockDriverAIOCB *blkmirror_aio_writev(BlockDriverState *bs, > + int64_t sector_num, > + QEMUIOVector *qiov, > + int nb_sectors, > + BlockDriverCompletionFunc *cb, > + void *opaque) > +{ > + BdrvMirrorState *m = bs->opaque; > + DupAIOCB *dcb = dup_aio_get(bs, cb, opaque); > + > + dcb->src_aiocb = bdrv_aio_writev(m->bs[0], sector_num, qiov, nb_sectors, > + &blkmirror_aio_cb, dcb); > + if (!dcb->src_aiocb) { > + qemu_aio_release(dcb); > + return NULL; > + } > + > + dcb->dest_aiocb = bdrv_aio_writev(m->bs[1], sector_num, qiov, nb_sectors, > + &blkmirror_aio_cb, dcb); > + if (!dcb->dest_aiocb) { > + bdrv_aio_cancel(dcb->src_aiocb); > + qemu_aio_release(dcb); > + return NULL; > + } > + > + return &dcb->common; > +} > + > +static BlockDriverAIOCB *blkmirror_aio_flush(BlockDriverState *bs, > + BlockDriverCompletionFunc *cb, > + void *opaque) > +{ > + BdrvMirrorState *m = bs->opaque; > + DupAIOCB *dcb = dup_aio_get(bs, cb, opaque); > + > + dcb->src_aiocb = bdrv_aio_flush(m->bs[0], &blkmirror_aio_cb, dcb); > + if (!dcb->src_aiocb) { > + qemu_aio_release(dcb); > + return NULL; > + } > + dcb->dest_aiocb = bdrv_aio_flush(m->bs[1], &blkmirror_aio_cb, dcb); > + if (!dcb->dest_aiocb) { > + bdrv_aio_cancel(dcb->src_aiocb); > + qemu_aio_release(dcb); > + return NULL; > + } > + > + return &dcb->common; > +} > + > +static int blkmirror_discard(BlockDriverState *bs, int64_t sector_num, > + int nb_sectors) > +{ > + BdrvMirrorState *m = bs->opaque; > + int ret; > + > + ret = bdrv_discard(m->bs[0], sector_num, nb_sectors); > + if (ret < 0) { > + return ret; > + } > + > + return bdrv_discard(m->bs[1], sector_num, nb_sectors); > +} > + > + > +static BlockDriver bdrv_blkmirror = { > + .format_name = "blkmirror", > + .protocol_name = "blkmirror", > + .instance_size = sizeof(BdrvMirrorState), > + > + .bdrv_getlength = blkmirror_getlength, > + > + .bdrv_file_open = blkmirror_open, > + .bdrv_close = blkmirror_close, > + .bdrv_flush = blkmirror_flush, > + .bdrv_discard = blkmirror_discard, > + > + .bdrv_aio_readv = blkmirror_aio_readv, > + .bdrv_aio_writev = blkmirror_aio_writev, > + .bdrv_aio_flush = blkmirror_aio_flush, > +}; > + > +static void bdrv_blkmirror_init(void) > +{ > + bdrv_register(&bdrv_blkmirror); > +} > + > +block_init(bdrv_blkmirror_init); > Index: qemu-block-copy/Makefile.objs > =================================================================== > --- qemu-block-copy.orig/Makefile.objs > +++ qemu-block-copy/Makefile.objs > @@ -22,7 +22,7 @@ block-nested-y += raw.o cow.o qcow.o vdi > block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o > qcow2-cache.o > block-nested-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o > block-nested-y += qed-check.o > -block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o > +block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o > blkmirror.o > block-nested-$(CONFIG_WIN32) += raw-win32.o > block-nested-$(CONFIG_POSIX) += raw-posix.o > block-nested-$(CONFIG_CURL) += curl.o > > > >