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[Qemu-devel] [RFC 11/12] qorum: Add qorum mechanism.
From: |
Benoît Canet |
Subject: |
[Qemu-devel] [RFC 11/12] qorum: Add qorum mechanism. |
Date: |
Thu, 2 Aug 2012 12:16:43 +0200 |
Signed-off-by: Benoit Canet <address@hidden>
---
block/qorum.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 78 insertions(+), 6 deletions(-)
diff --git a/block/qorum.c b/block/qorum.c
index 772d138..1f307b6 100644
--- a/block/qorum.c
+++ b/block/qorum.c
@@ -175,7 +175,7 @@ static int qorum_check_ret(QorumAIOCB *acb)
static void qorum_aio_bh(void *opaque)
{
QorumAIOCB *acb = opaque;
- int i;
+ int i, ret;
for (i = 0; i <= 2; i++) {
if (acb->aios[i].buf) {
@@ -185,7 +185,12 @@ static void qorum_aio_bh(void *opaque)
}
qemu_bh_delete(acb->bh);
- acb->common.cb(acb->common.opaque, qorum_check_ret(acb));
+ if (acb->vote_ret) {
+ ret = acb->vote_ret;
+ } else {
+ ret = qorum_check_ret(acb);
+ }
+ acb->common.cb(acb->common.opaque, ret);
if (acb->finished) {
*acb->finished = true;
}
@@ -229,10 +234,75 @@ static void qorum_aio_cb(void *opaque, int ret)
sacb->ret = ret;
acb->count++;
assert(acb->count <= 3);
- if (acb->count == 3) {
- acb->bh = qemu_bh_new(qorum_aio_bh, acb);
- qemu_bh_schedule(acb->bh);
+ if (acb->count < 3) {
+ return;
}
+
+ /* Do the qorum */
+ if (acb->vote) {
+ acb->vote(acb);
+ }
+
+ acb->bh = qemu_bh_new(qorum_aio_bh, acb);
+ qemu_bh_schedule(acb->bh);
+}
+
+static void qorum_print_bad(QorumAIOCB *acb, const char *filename)
+{
+ fprintf(stderr, "qorum: corrected error in qorum file %s: sector_num=%"
+ PRId64 " nb_sectors=%i\n", filename, acb->sector_num,
+ acb->nb_sectors);
+}
+
+static void qorum_print_failure(QorumAIOCB *acb)
+{
+ fprintf(stderr, "qorum: failure sector_num=%" PRId64 " nb_sectors=%i\n",
+ acb->sector_num, acb->nb_sectors);
+}
+
+static void qorum_copy_qiov(QEMUIOVector *dest, QEMUIOVector *source)
+{
+ int i;
+ for (i = 0; i < source->niov; i++) {
+ memcpy(dest->iov[i].iov_base,
+ source->iov[i].iov_base,
+ source->iov[i].iov_len);
+ dest->iov[i].iov_len = source->iov[i].iov_len;
+ }
+ dest->niov = source->niov;
+ dest->nalloc = source->nalloc;
+ dest->size = source->size;
+}
+
+static void qorum_vote(QorumAIOCB *acb)
+{
+ ssize_t a_b, b_c, a_c;
+ a_b = blkverify_iovec_compare(&acb->qiovs[0], &acb->qiovs[1]);
+ b_c = blkverify_iovec_compare(&acb->qiovs[1], &acb->qiovs[2]);
+
+ /* Three vector identical -> qorum */
+ if (a_b == b_c && a_b == -1) {
+ qorum_copy_qiov(acb->qiov, &acb->qiovs[0]); /*clone a */
+ return;
+ }
+ if (a_b == -1) {
+ qorum_print_bad(acb, "C");
+ qorum_copy_qiov(acb->qiov, &acb->qiovs[0]); /*clone a */
+ return;
+ }
+ if (b_c == -1) {
+ qorum_print_bad(acb, "A");
+ qorum_copy_qiov(acb->qiov, &acb->qiovs[1]); /*clone b */
+ return;
+ }
+ a_c = blkverify_iovec_compare(&acb->qiovs[0], &acb->qiovs[2]);
+ if (a_c == -1) {
+ qorum_print_bad(acb, "B");
+ qorum_copy_qiov(acb->qiov, &acb->qiovs[0]); /*clone a */
+ return;
+ }
+ qorum_print_failure(acb);
+ acb->vote_ret = -EIO;
}
static BlockDriverAIOCB *qorum_aio_readv(BlockDriverState *bs,
@@ -247,6 +317,8 @@ static BlockDriverAIOCB *qorum_aio_readv(BlockDriverState
*bs,
nb_sectors, cb, opaque);
int i;
+ acb->vote = qorum_vote;
+
for (i = 0; i <= 2; i++) {
acb->aios[i].buf = qemu_blockalign(bs->file, qiov->size);
qemu_iovec_init(&acb->qiovs[i], qiov->niov);
@@ -254,7 +326,7 @@ static BlockDriverAIOCB *qorum_aio_readv(BlockDriverState
*bs,
}
for (i = 0; i <= 2; i++) {
- bdrv_aio_readv(s->bs[i], sector_num, qiov, nb_sectors,
+ bdrv_aio_readv(s->bs[i], sector_num, &acb->qiovs[i], nb_sectors,
qorum_aio_cb, &acb->aios[i]);
}
--
1.7.9.5
- [Qemu-devel] [RFC 06/12] qorum: Add qorum_getlength()., (continued)
- [Qemu-devel] [RFC 06/12] qorum: Add qorum_getlength()., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 03/12] qorum: Create BDRVQorumState and BlkDriver and do init., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 05/12] qorum: Add qorum_close()., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 02/12] qorum: Add QorumSingleAIOCB and QorumAIOCB., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 10/12] qorum: Add qorum_aio_readv., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 07/12] qorum: Add qorum_aio_writev and its dependencies., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 12/12] qorum: build feature into QEMU., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 08/12] blkverify: Make blkverify_iovec_clone() and blkverify_iovec_compare() public, Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 09/12] qorum: Add qorum_co_flush()., Benoît Canet, 2012/08/02
- [Qemu-devel] [RFC 11/12] qorum: Add qorum mechanism.,
Benoît Canet <=
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency, Eric Blake, 2012/08/02
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency, Anthony Liguori, 2012/08/02
- Re: [Qemu-devel] [RFC 00/12] Qorum disk image corruption resiliency, Blue Swirl, 2012/08/03