Message ID | 20110606165823.588925767@amt.cnet |
---|---|
State | New |
Headers | show |
On Mon, 6 Jun 2011, Marcelo Tosatti wrote: > Mirrored writes are used by live block copy. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > > Index: qemu-block-copy/block/blkmirror.c > =================================================================== > --- /dev/null > +++ qemu-block-copy/block/blkmirror.c > @@ -0,0 +1,277 @@ > +/* > + * 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; > + > +typedef struct DupAIOCB DupAIOCB; > + > +typedef struct SingleAIOCB { > + BlockDriverAIOCB *aiocb; > + int finished; > + DupAIOCB *parent; > +} SingleAIOCB; > + > +struct DupAIOCB { > + BlockDriverAIOCB common; > + int count; > + > + BlockDriverCompletionFunc *cb; > + SingleAIOCB aios[2]; > + int ret; > +}; > + > +/* 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, escape, i, n; > + char *raw; > + > + /* Parse the blkmirror: prefix */ > + if (strncmp(filename, "blkmirror:", strlen("blkmirror:"))) { > + return -EINVAL; > + } > + filename += strlen("blkmirror:"); > + > + /* Parse the raw image filename */ > + raw = malloc(strlen(filename)); > + escape = 0; > + for (i = n = 0; i < strlen(filename); i++) { > + if (!escape && filename[i] == ':') { > + break; > + } > + if (!escape && filename[i] == '\\') { > + escape = 1; > + } else { > + escape = 0; > + } > + > + if (!escape) { > + raw[n++] = filename[i]; > + } > + } > + raw[n] = '\0'; This potentially writes past the memory allocated for raw. > + > + m->bs[0] = bdrv_new(""); > + if (m->bs[0] == NULL) { > + return -ENOMEM; > + } > + ret = bdrv_open(m->bs[0], raw, flags, NULL); > + free(raw); > + if (ret < 0) { > + return ret; > + } > + filename += i + 1; > + > + m->bs[1] = bdrv_new(""); > + if (m->bs[1] == NULL) { > + return -ENOMEM; > + } > + ret = bdrv_open(m->bs[1], filename, flags, NULL); > + 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); > +} > + > +static void dup_aio_cancel(BlockDriverAIOCB *blockacb) > +{ > + DupAIOCB *acb = container_of(blockacb, DupAIOCB, common); > + int i; > + > + for (i = 0 ; i < 2; i++) { > + if (!acb->aios[i].finished) { > + bdrv_aio_cancel(acb->aios[i].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) > +{ > + SingleAIOCB *scb = opaque; > + DupAIOCB *dcb = scb->parent; > + > + scb->finished = 1; > + dcb->count--; > + assert(dcb->count >= 0); > + if (ret < 0) { > + dcb->ret = ret; > + } > + if (dcb->count == 0) { > + dcb->common.cb(dcb->common.opaque, dcb->ret); > + qemu_aio_release(dcb); > + } > +} > + > +static DupAIOCB *dup_aio_get(BlockDriverState *bs, > + BlockDriverCompletionFunc *cb, > + void *opaque) > +{ > + DupAIOCB *dcb; > + int i; > + > + dcb = qemu_aio_get(&dup_aio_pool, bs, cb, opaque); > + if (!dcb) { > + return NULL; > + } > + dcb->count = 2; > + for (i = 0; i < 2; i++) { > + dcb->aios[i].parent = dcb; > + dcb->aios[i].finished = 0; > + } > + dcb->ret = 0; > + > + 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); > + int i; > + > + for (i = 0; i < 2; i++) { > + dcb->aios[i].aiocb = bdrv_aio_writev(m->bs[i], sector_num, qiov, > + nb_sectors, &blkmirror_aio_cb, > + &dcb->aios[i]); > + if (!dcb->aios[i].aiocb) { > + int a; > + > + for (a = 0; a < i; a++) { > + bdrv_aio_cancel(dcb->aios[i].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); > + int i; > + > + for (i = 0; i < 2; i++) { > + dcb->aios[i].aiocb = bdrv_aio_flush(m->bs[i], &blkmirror_aio_cb, > + &dcb->aios[i]); > + if (!dcb->aios[i].aiocb) { > + int a; > + > + for (a = 0; a < i; a++) { > + bdrv_aio_cancel(dcb->aios[i].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 > Index: qemu-block-copy/docs/blkmirror.txt > =================================================================== > --- /dev/null > +++ qemu-block-copy/docs/blkmirror.txt > @@ -0,0 +1,15 @@ > +Block mirror driver > +------------------- > + > +This driver will mirror writes to two distinct images. > +Its used internally by live block copy. > + > +Format > +------ > + > +blkmirror:/image1.img:/image2.img > + > +'\' (backslash) can be used to escape colon processing > +as a separator. > + > + > > >
On Mon, Jun 6, 2011 at 5:55 PM, Marcelo Tosatti <mtosatti@redhat.com> wrote: > +/* 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, escape, i, n; > + char *raw; > + > + /* Parse the blkmirror: prefix */ > + if (strncmp(filename, "blkmirror:", strlen("blkmirror:"))) { > + return -EINVAL; > + } > + filename += strlen("blkmirror:"); > + > + /* Parse the raw image filename */ > + raw = malloc(strlen(filename)); Please use qemu_malloc()/qemu_strdup()/qemu_free() instead of the system library versions. I'm guilty of this in blkverify :(. > + escape = 0; > + for (i = n = 0; i < strlen(filename); i++) { > + if (!escape && filename[i] == ':') { > + break; > + } > + if (!escape && filename[i] == '\\') { > + escape = 1; > + } else { > + escape = 0; > + } > + > + if (!escape) { > + raw[n++] = filename[i]; > + } > + } > + raw[n] = '\0'; > + > + m->bs[0] = bdrv_new(""); > + if (m->bs[0] == NULL) { > + return -ENOMEM; raw is leaked. > + } > + ret = bdrv_open(m->bs[0], raw, flags, NULL); This isn't necessarily a "raw" file. filename0 and filename1 would be clearer IMO. > + free(raw); > + if (ret < 0) { > + return ret; > + } > + filename += i + 1; Please document that escaping only takes effect in filename0. After the second ':' you may no longer escape. For sanity perhaps the whole string should be unescaped. > + > + m->bs[1] = bdrv_new(""); > + if (m->bs[1] == NULL) { bs[0] is leaked. > + return -ENOMEM; > + } > + ret = bdrv_open(m->bs[1], filename, flags, NULL); > + 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 values should be checked. Stefan
Index: qemu-block-copy/block/blkmirror.c =================================================================== --- /dev/null +++ qemu-block-copy/block/blkmirror.c @@ -0,0 +1,277 @@ +/* + * 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; + +typedef struct DupAIOCB DupAIOCB; + +typedef struct SingleAIOCB { + BlockDriverAIOCB *aiocb; + int finished; + DupAIOCB *parent; +} SingleAIOCB; + +struct DupAIOCB { + BlockDriverAIOCB common; + int count; + + BlockDriverCompletionFunc *cb; + SingleAIOCB aios[2]; + int ret; +}; + +/* 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, escape, i, n; + char *raw; + + /* Parse the blkmirror: prefix */ + if (strncmp(filename, "blkmirror:", strlen("blkmirror:"))) { + return -EINVAL; + } + filename += strlen("blkmirror:"); + + /* Parse the raw image filename */ + raw = malloc(strlen(filename)); + escape = 0; + for (i = n = 0; i < strlen(filename); i++) { + if (!escape && filename[i] == ':') { + break; + } + if (!escape && filename[i] == '\\') { + escape = 1; + } else { + escape = 0; + } + + if (!escape) { + raw[n++] = filename[i]; + } + } + raw[n] = '\0'; + + m->bs[0] = bdrv_new(""); + if (m->bs[0] == NULL) { + return -ENOMEM; + } + ret = bdrv_open(m->bs[0], raw, flags, NULL); + free(raw); + if (ret < 0) { + return ret; + } + filename += i + 1; + + m->bs[1] = bdrv_new(""); + if (m->bs[1] == NULL) { + return -ENOMEM; + } + ret = bdrv_open(m->bs[1], filename, flags, NULL); + 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); +} + +static void dup_aio_cancel(BlockDriverAIOCB *blockacb) +{ + DupAIOCB *acb = container_of(blockacb, DupAIOCB, common); + int i; + + for (i = 0 ; i < 2; i++) { + if (!acb->aios[i].finished) { + bdrv_aio_cancel(acb->aios[i].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) +{ + SingleAIOCB *scb = opaque; + DupAIOCB *dcb = scb->parent; + + scb->finished = 1; + dcb->count--; + assert(dcb->count >= 0); + if (ret < 0) { + dcb->ret = ret; + } + if (dcb->count == 0) { + dcb->common.cb(dcb->common.opaque, dcb->ret); + qemu_aio_release(dcb); + } +} + +static DupAIOCB *dup_aio_get(BlockDriverState *bs, + BlockDriverCompletionFunc *cb, + void *opaque) +{ + DupAIOCB *dcb; + int i; + + dcb = qemu_aio_get(&dup_aio_pool, bs, cb, opaque); + if (!dcb) { + return NULL; + } + dcb->count = 2; + for (i = 0; i < 2; i++) { + dcb->aios[i].parent = dcb; + dcb->aios[i].finished = 0; + } + dcb->ret = 0; + + 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); + int i; + + for (i = 0; i < 2; i++) { + dcb->aios[i].aiocb = bdrv_aio_writev(m->bs[i], sector_num, qiov, + nb_sectors, &blkmirror_aio_cb, + &dcb->aios[i]); + if (!dcb->aios[i].aiocb) { + int a; + + for (a = 0; a < i; a++) { + bdrv_aio_cancel(dcb->aios[i].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); + int i; + + for (i = 0; i < 2; i++) { + dcb->aios[i].aiocb = bdrv_aio_flush(m->bs[i], &blkmirror_aio_cb, + &dcb->aios[i]); + if (!dcb->aios[i].aiocb) { + int a; + + for (a = 0; a < i; a++) { + bdrv_aio_cancel(dcb->aios[i].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 Index: qemu-block-copy/docs/blkmirror.txt =================================================================== --- /dev/null +++ qemu-block-copy/docs/blkmirror.txt @@ -0,0 +1,15 @@ +Block mirror driver +------------------- + +This driver will mirror writes to two distinct images. +Its used internally by live block copy. + +Format +------ + +blkmirror:/image1.img:/image2.img + +'\' (backslash) can be used to escape colon processing +as a separator. + +
Mirrored writes are used by live block copy. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>