Message ID | 1330102144-14491-1-git-send-email-fsimonce@redhat.com |
---|---|
State | New |
Headers | show |
On 02/24/2012 09:49 AM, Federico Simoncelli wrote: > From: Marcelo Tosatti <mtosatti@redhat.com> > > Mirrored writes are used by live block copy. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > Signed-off-by: Federico Simoncelli <fsimonce@redhat.com> > --- > +++ b/block/blkmirror.c > @@ -0,0 +1,247 @@ > +/* > + * Block driver for mirrored writes. > + * > + * Copyright (C) 2011 Red Hat, Inc. It's 2012 now. > +++ b/docs/blkmirror.txt > @@ -0,0 +1,16 @@ > +Block mirror driver > +------------------- > + > +This driver will mirror writes to two distinct images. > +It's used internally by live block copy. > + > +Format > +------ > + > +blkmirror:/image1.img:/image2.img > + > +'\' (backslash) can be used to escape colon processing > +as a separator, in the first image filename. > +Backslashes themselves also can be escaped as '\\'. Is the escaping of : and \ only necessary for image1.img, or for both image1 and image2? I need to know if the parser is consistent for both arguments, but this wording makes it sound like it is only for the first argument.
----- Original Message ----- > From: "Eric Blake" <eblake@redhat.com> > To: "Federico Simoncelli" <fsimonce@redhat.com> > Cc: qemu-devel@nongnu.org, kwolf@redhat.com, mtosatti@redhat.com, armbru@redhat.com, lcapitulino@redhat.com, > pbonzini@redhat.com > Sent: Friday, February 24, 2012 6:02:36 PM > Subject: Re: [Qemu-devel] [PATCH 1/2 v2] Add blkmirror block driver > > +++ b/docs/blkmirror.txt > > @@ -0,0 +1,16 @@ > > +Block mirror driver > > +------------------- > > + > > +This driver will mirror writes to two distinct images. > > +It's used internally by live block copy. > > + > > +Format > > +------ > > + > > +blkmirror:/image1.img:/image2.img > > + > > +'\' (backslash) can be used to escape colon processing > > +as a separator, in the first image filename. > > +Backslashes themselves also can be escaped as '\\'. > > Is the escaping of : and \ only necessary for image1.img, or for both > image1 and image2? I need to know if the parser is consistent for > both > arguments, but this wording makes it sound like it is only for the > first > argument. Yes it is only for the first argument.
On Fri, 24 Feb 2012 16:49:03 +0000 Federico Simoncelli <fsimonce@redhat.com> wrote: > From: Marcelo Tosatti <mtosatti@redhat.com> > > Mirrored writes are used by live block copy. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > Signed-off-by: Federico Simoncelli <fsimonce@redhat.com> > --- > Makefile.objs | 2 +- > block/blkmirror.c | 247 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > docs/blkmirror.txt | 16 ++++ > 3 files changed, 264 insertions(+), 1 deletions(-) > create mode 100644 block/blkmirror.c > create mode 100644 docs/blkmirror.txt > > diff --git a/Makefile.objs b/Makefile.objs > index 67ee3df..6020308 100644 > --- a/Makefile.objs > +++ b/Makefile.objs > @@ -34,7 +34,7 @@ block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vv > 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-y += stream.o > block-nested-$(CONFIG_WIN32) += raw-win32.o > block-nested-$(CONFIG_POSIX) += raw-posix.o > diff --git a/block/blkmirror.c b/block/blkmirror.c > new file mode 100644 > index 0000000..49e3381 > --- /dev/null > +++ b/block/blkmirror.c > @@ -0,0 +1,247 @@ > +/* > + * 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 *filename2; > + > + /* Parse the blkmirror: prefix */ > + if (strncmp(filename, "blkmirror:", strlen("blkmirror:"))) { > + return -EINVAL; > + } > + filename += strlen("blkmirror:"); Minor: you can use strstart() here. > + > + /* Parse the raw image filename */ > + filename2 = g_malloc(strlen(filename)+1); > + 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) { > + filename2[n++] = filename[i]; > + } > + } > + filename2[n] = '\0'; You're escaping only the first image name string, is that intentional? > + > + m->bs[0] = bdrv_new(""); > + if (m->bs[0] == NULL) { > + g_free(filename2); > + return -ENOMEM; > + } > + ret = bdrv_open(m->bs[0], filename2, flags, NULL); > + g_free(filename2); > + if (ret < 0) { Leaking m->bs[0]? > + return ret; > + } > + filename += i + 1; > + > + m->bs[1] = bdrv_new(""); > + if (m->bs[1] == NULL) { > + bdrv_delete(m->bs[0]); > + return -ENOMEM; > + } > + ret = bdrv_open(m->bs[1], filename, flags | BDRV_O_NO_BACKING, NULL); > + if (ret < 0) { > + bdrv_delete(m->bs[0]); What about m->bs[1]? > + 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 coroutine_fn int blkmirror_co_flush(BlockDriverState *bs) > +{ > + BdrvMirrorState *m = bs->opaque; > + int ret; > + > + ret = bdrv_co_flush(m->bs[0]); > + if (ret < 0) { > + return ret; > + } > + > + return bdrv_co_flush(m->bs[1]); > +} > + > +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]); > + } > + > + return &dcb->common; > +} > + > +static coroutine_fn int blkmirror_co_discard(BlockDriverState *bs, > + int64_t sector_num, int nb_sectors) > +{ > + BdrvMirrorState *m = bs->opaque; > + int ret; > + > + ret = bdrv_co_discard(m->bs[0], sector_num, nb_sectors); > + if (ret < 0) { > + return ret; > + } > + > + return bdrv_co_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_co_flush_to_disk = blkmirror_co_flush, > + .bdrv_co_discard = blkmirror_co_discard, > + > + .bdrv_aio_readv = blkmirror_aio_readv, > + .bdrv_aio_writev = blkmirror_aio_writev, > +}; > + > +static void bdrv_blkmirror_init(void) > +{ > + bdrv_register(&bdrv_blkmirror); > +} > + > +block_init(bdrv_blkmirror_init); > diff --git a/docs/blkmirror.txt b/docs/blkmirror.txt > new file mode 100644 > index 0000000..cf73f3f > --- /dev/null > +++ b/docs/blkmirror.txt > @@ -0,0 +1,16 @@ > +Block mirror driver > +------------------- > + > +This driver will mirror writes to two distinct images. > +It's used internally by live block copy. > + > +Format > +------ > + > +blkmirror:/image1.img:/image2.img > + > +'\' (backslash) can be used to escape colon processing > +as a separator, in the first image filename. > +Backslashes themselves also can be escaped as '\\'. > + > +
On 02/24/2012 06:02 PM, Eric Blake wrote: > Is the escaping of : and \ only necessary for image1.img, or for both > image1 and image2? I need to know if the parser is consistent for both > arguments, but this wording makes it sound like it is only for the first > argument. libvirt is completely insulated from this. Paolo
----- Original Message ----- > From: "Luiz Capitulino" <lcapitulino@redhat.com> > To: "Federico Simoncelli" <fsimonce@redhat.com> > Cc: qemu-devel@nongnu.org, mtosatti@redhat.com, pbonzini@redhat.com, kwolf@redhat.com, armbru@redhat.com > Sent: Friday, February 24, 2012 7:17:22 PM > Subject: Re: [PATCH 1/2 v2] Add blkmirror block driver > > On Fri, 24 Feb 2012 16:49:03 +0000 > Federico Simoncelli <fsimonce@redhat.com> wrote: > > > + /* Parse the raw image filename */ > > + filename2 = g_malloc(strlen(filename)+1); > > + 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) { > > + filename2[n++] = filename[i]; > > + } > > + } > > + filename2[n] = '\0'; > > You're escaping only the first image name string, is that > intentional? Yes, it was also documented here by Marcelo: > > diff --git a/docs/blkmirror.txt b/docs/blkmirror.txt > > new file mode 100644 > > index 0000000..cf73f3f > > --- /dev/null > > +++ b/docs/blkmirror.txt > > @@ -0,0 +1,16 @@ > > +Block mirror driver > > +------------------- > > + > > +This driver will mirror writes to two distinct images. > > +It's used internally by live block copy. > > + > > +Format > > +------ > > + > > +blkmirror:/image1.img:/image2.img > > + > > +'\' (backslash) can be used to escape colon processing > > +as a separator, in the first image filename. > > +Backslashes themselves also can be escaped as '\\'. > > + > > + Anyway this format is encapsulated by blockdev-migrate.
diff --git a/Makefile.objs b/Makefile.objs index 67ee3df..6020308 100644 --- a/Makefile.objs +++ b/Makefile.objs @@ -34,7 +34,7 @@ block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vv 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-y += stream.o block-nested-$(CONFIG_WIN32) += raw-win32.o block-nested-$(CONFIG_POSIX) += raw-posix.o diff --git a/block/blkmirror.c b/block/blkmirror.c new file mode 100644 index 0000000..49e3381 --- /dev/null +++ b/block/blkmirror.c @@ -0,0 +1,247 @@ +/* + * 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 *filename2; + + /* Parse the blkmirror: prefix */ + if (strncmp(filename, "blkmirror:", strlen("blkmirror:"))) { + return -EINVAL; + } + filename += strlen("blkmirror:"); + + /* Parse the raw image filename */ + filename2 = g_malloc(strlen(filename)+1); + 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) { + filename2[n++] = filename[i]; + } + } + filename2[n] = '\0'; + + m->bs[0] = bdrv_new(""); + if (m->bs[0] == NULL) { + g_free(filename2); + return -ENOMEM; + } + ret = bdrv_open(m->bs[0], filename2, flags, NULL); + g_free(filename2); + if (ret < 0) { + return ret; + } + filename += i + 1; + + m->bs[1] = bdrv_new(""); + if (m->bs[1] == NULL) { + bdrv_delete(m->bs[0]); + return -ENOMEM; + } + ret = bdrv_open(m->bs[1], filename, flags | BDRV_O_NO_BACKING, 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 coroutine_fn int blkmirror_co_flush(BlockDriverState *bs) +{ + BdrvMirrorState *m = bs->opaque; + int ret; + + ret = bdrv_co_flush(m->bs[0]); + if (ret < 0) { + return ret; + } + + return bdrv_co_flush(m->bs[1]); +} + +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]); + } + + return &dcb->common; +} + +static coroutine_fn int blkmirror_co_discard(BlockDriverState *bs, + int64_t sector_num, int nb_sectors) +{ + BdrvMirrorState *m = bs->opaque; + int ret; + + ret = bdrv_co_discard(m->bs[0], sector_num, nb_sectors); + if (ret < 0) { + return ret; + } + + return bdrv_co_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_co_flush_to_disk = blkmirror_co_flush, + .bdrv_co_discard = blkmirror_co_discard, + + .bdrv_aio_readv = blkmirror_aio_readv, + .bdrv_aio_writev = blkmirror_aio_writev, +}; + +static void bdrv_blkmirror_init(void) +{ + bdrv_register(&bdrv_blkmirror); +} + +block_init(bdrv_blkmirror_init); diff --git a/docs/blkmirror.txt b/docs/blkmirror.txt new file mode 100644 index 0000000..cf73f3f --- /dev/null +++ b/docs/blkmirror.txt @@ -0,0 +1,16 @@ +Block mirror driver +------------------- + +This driver will mirror writes to two distinct images. +It's used internally by live block copy. + +Format +------ + +blkmirror:/image1.img:/image2.img + +'\' (backslash) can be used to escape colon processing +as a separator, in the first image filename. +Backslashes themselves also can be escaped as '\\'. + +