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[Qemu-devel] [PULL 03/39] qcow2: Make copy_sectors() byte based
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PULL 03/39] qcow2: Make copy_sectors() byte based |
Date: |
Thu, 16 Jun 2016 16:07:52 +0200 |
This will allow copy on write operations where the overwritten part of
the cluster is not aligned to sector boundaries.
Also rename the function because it has nothing to do with sectors any
more.
Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
block/qcow2-cluster.c | 55 +++++++++++++++++++++++++--------------------------
1 file changed, 27 insertions(+), 28 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 277764f..b7671fc 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -390,22 +390,18 @@ int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t
sector_num,
return 0;
}
-static int coroutine_fn copy_sectors(BlockDriverState *bs,
- uint64_t start_sect,
- uint64_t cluster_offset,
- int n_start, int n_end)
+static int coroutine_fn do_perform_cow(BlockDriverState *bs,
+ uint64_t src_cluster_offset,
+ uint64_t cluster_offset,
+ int offset_in_cluster,
+ int bytes)
{
BDRVQcow2State *s = bs->opaque;
QEMUIOVector qiov;
struct iovec iov;
- int n, ret;
-
- n = n_end - n_start;
- if (n <= 0) {
- return 0;
- }
+ int ret;
- iov.iov_len = n * BDRV_SECTOR_SIZE;
+ iov.iov_len = bytes;
iov.iov_base = qemu_try_blockalign(bs, iov.iov_len);
if (iov.iov_base == NULL) {
return -ENOMEM;
@@ -424,18 +420,21 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
* interface. This avoids double I/O throttling and request tracking,
* which can lead to deadlock when block layer copy-on-read is enabled.
*/
- ret = bs->drv->bdrv_co_preadv(bs, (start_sect + n_start) *
BDRV_SECTOR_SIZE,
- n * BDRV_SECTOR_SIZE, &qiov, 0);
+ ret = bs->drv->bdrv_co_preadv(bs, src_cluster_offset + offset_in_cluster,
+ bytes, &qiov, 0);
if (ret < 0) {
goto out;
}
if (bs->encrypted) {
Error *err = NULL;
+ int64_t sector = (cluster_offset + offset_in_cluster)
+ >> BDRV_SECTOR_BITS;
assert(s->cipher);
- if (qcow2_encrypt_sectors(s, start_sect + n_start,
- iov.iov_base, iov.iov_base, n,
- true, &err) < 0) {
+ assert((offset_in_cluster & ~BDRV_SECTOR_MASK) == 0);
+ assert((bytes & ~BDRV_SECTOR_MASK) == 0);
+ if (qcow2_encrypt_sectors(s, sector, iov.iov_base, iov.iov_base,
+ bytes >> BDRV_SECTOR_BITS, true, &err) < 0) {
ret = -EIO;
error_free(err);
goto out;
@@ -443,14 +442,14 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
}
ret = qcow2_pre_write_overlap_check(bs, 0,
- cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE);
+ cluster_offset + offset_in_cluster, bytes);
if (ret < 0) {
goto out;
}
BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
- ret = bdrv_co_writev(bs->file->bs, (cluster_offset >> 9) + n_start, n,
- &qiov);
+ ret = bdrv_co_pwritev(bs->file->bs, cluster_offset + offset_in_cluster,
+ bytes, &qiov, 0);
if (ret < 0) {
goto out;
}
@@ -745,9 +744,8 @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m,
Qcow2COWRegion *r)
}
qemu_co_mutex_unlock(&s->lock);
- ret = copy_sectors(bs, m->offset / BDRV_SECTOR_SIZE, m->alloc_offset,
- r->offset / BDRV_SECTOR_SIZE,
- r->offset / BDRV_SECTOR_SIZE + r->nb_sectors);
+ ret = do_perform_cow(bs, m->offset, m->alloc_offset,
+ r->offset, r->nb_sectors * BDRV_SECTOR_SIZE);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
@@ -809,13 +807,14 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m)
assert(l2_index + m->nb_clusters <= s->l2_size);
for (i = 0; i < m->nb_clusters; i++) {
/* if two concurrent writes happen to the same unallocated cluster
- * each write allocates separate cluster and writes data concurrently.
- * The first one to complete updates l2 table with pointer to its
- * cluster the second one has to do RMW (which is done above by
- * copy_sectors()), update l2 table with its cluster pointer and free
- * old cluster. This is what this loop does */
- if(l2_table[l2_index + i] != 0)
+ * each write allocates separate cluster and writes data concurrently.
+ * The first one to complete updates l2 table with pointer to its
+ * cluster the second one has to do RMW (which is done above by
+ * perform_cow()), update l2 table with its cluster pointer and free
+ * old cluster. This is what this loop does */
+ if (l2_table[l2_index + i] != 0) {
old_cluster[j++] = l2_table[l2_index + i];
+ }
l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
(i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
--
1.8.3.1
- [Qemu-devel] [PULL 00/39] Block layer patches, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 04/39] qcow2: Use bytes instead of sectors for QCowL2Meta, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 01/39] qcow2: Work with bytes in qcow2_get_cluster_offset(), Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 02/39] qcow2: Implement .bdrv_co_preadv(), Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 06/39] blockdev: clarify error on attempt to open locked tray, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 05/39] qcow2: Implement .bdrv_co_pwritev(), Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 07/39] hmp: acquire aio_context in hmp_qemu_io, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 14/39] block: Prepare bdrv_aligned_preadv() for byte-aligned requests, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 03/39] qcow2: Make copy_sectors() byte based,
Kevin Wolf <=
- [Qemu-devel] [PULL 11/39] block: Assert that flags are in range, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 15/39] block: Prepare bdrv_aligned_pwritev() for byte-aligned requests, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 12/39] block: drop support for using qcow[2] encryption with system emulators, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 08/39] m25p80: fix test on blk_pread() return value, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 09/39] qemu-img bench: Fix uninitialised writethrough mode, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 10/39] block: Avoid bogus flags during mirroring, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 13/39] block: Byte-based bdrv_co_do_copy_on_readv(), Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 19/39] linux-aio: Cancel BH if not needed, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 20/39] doc: Fix mailing list address in tests/qemu-iotests/README, Kevin Wolf, 2016/06/16
- [Qemu-devel] [PULL 16/39] raw-posix: Switch to bdrv_co_* interfaces, Kevin Wolf, 2016/06/16