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-rw-r--r--block/qed.c38
-rw-r--r--block/qed.h1
2 files changed, 31 insertions, 8 deletions
diff --git a/block/qed.c b/block/qed.c
index b69374b..cd4872b 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -761,17 +761,19 @@ static BDRVQEDState *acb_to_s(QEDAIOCB *acb)
/**
* Read from the backing file or zero-fill if no backing file
*
- * @s: QED state
- * @pos: Byte position in device
- * @qiov: Destination I/O vector
- * @cb: Completion function
- * @opaque: User data for completion function
+ * @s: QED state
+ * @pos: Byte position in device
+ * @qiov: Destination I/O vector
+ * @backing_qiov: Possibly shortened copy of qiov, to be allocated here
+ * @cb: Completion function
+ * @opaque: User data for completion function
*
* This function reads qiov->size bytes starting at pos from the backing file.
* If there is no backing file then zeroes are read.
*/
static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
QEMUIOVector *qiov,
+ QEMUIOVector **backing_qiov,
BlockDriverCompletionFunc *cb, void *opaque)
{
uint64_t backing_length = 0;
@@ -804,15 +806,21 @@ static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
/* If the read straddles the end of the backing file, shorten it */
size = MIN((uint64_t)backing_length - pos, qiov->size);
+ assert(*backing_qiov == NULL);
+ *backing_qiov = g_new(QEMUIOVector, 1);
+ qemu_iovec_init(*backing_qiov, qiov->niov);
+ qemu_iovec_concat(*backing_qiov, qiov, 0, size);
+
BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO);
bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE,
- qiov, size / BDRV_SECTOR_SIZE, cb, opaque);
+ *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque);
}
typedef struct {
GenericCB gencb;
BDRVQEDState *s;
QEMUIOVector qiov;
+ QEMUIOVector *backing_qiov;
struct iovec iov;
uint64_t offset;
} CopyFromBackingFileCB;
@@ -829,6 +837,12 @@ static void qed_copy_from_backing_file_write(void *opaque, int ret)
CopyFromBackingFileCB *copy_cb = opaque;
BDRVQEDState *s = copy_cb->s;
+ if (copy_cb->backing_qiov) {
+ qemu_iovec_destroy(copy_cb->backing_qiov);
+ g_free(copy_cb->backing_qiov);
+ copy_cb->backing_qiov = NULL;
+ }
+
if (ret) {
qed_copy_from_backing_file_cb(copy_cb, ret);
return;
@@ -866,11 +880,12 @@ static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos,
copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque);
copy_cb->s = s;
copy_cb->offset = offset;
+ copy_cb->backing_qiov = NULL;
copy_cb->iov.iov_base = qemu_blockalign(s->bs, len);
copy_cb->iov.iov_len = len;
qemu_iovec_init_external(&copy_cb->qiov, &copy_cb->iov, 1);
- qed_read_backing_file(s, pos, &copy_cb->qiov,
+ qed_read_backing_file(s, pos, &copy_cb->qiov, &copy_cb->backing_qiov,
qed_copy_from_backing_file_write, copy_cb);
}
@@ -1313,7 +1328,7 @@ static void qed_aio_read_data(void *opaque, int ret,
return;
} else if (ret != QED_CLUSTER_FOUND) {
qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov,
- qed_aio_next_io, acb);
+ &acb->backing_qiov, qed_aio_next_io, acb);
return;
}
@@ -1339,6 +1354,12 @@ static void qed_aio_next_io(void *opaque, int ret)
trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size);
+ if (acb->backing_qiov) {
+ qemu_iovec_destroy(acb->backing_qiov);
+ g_free(acb->backing_qiov);
+ acb->backing_qiov = NULL;
+ }
+
/* Handle I/O error */
if (ret) {
qed_aio_complete(acb, ret);
@@ -1378,6 +1399,7 @@ static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs,
acb->qiov_offset = 0;
acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE;
+ acb->backing_qiov = NULL;
acb->request.l2_table = NULL;
qemu_iovec_init(&acb->cur_qiov, qiov->niov);
diff --git a/block/qed.h b/block/qed.h
index b024751..2b0e724 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -142,6 +142,7 @@ typedef struct QEDAIOCB {
/* Current cluster scatter-gather list */
QEMUIOVector cur_qiov;
+ QEMUIOVector *backing_qiov;
uint64_t cur_pos; /* position on block device, in bytes */
uint64_t cur_cluster; /* cluster offset in image file */
unsigned int cur_nclusters; /* number of clusters being accessed */
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