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[Qemu-block] [PATCH 03/13] block: Add .bdrv_co_pwrite_zeroes()
From: |
Eric Blake |
Subject: |
[Qemu-block] [PATCH 03/13] block: Add .bdrv_co_pwrite_zeroes() |
Date: |
Tue, 24 May 2016 16:25:22 -0600 |
Update bdrv_co_do_write_zeroes() to be byte-based, and select
between the new byte-based bdrv_co_pwrite_zeroes() or the old
bdrv_co_write_zeroes(). The next patches will convert drivers,
then remove the old interface.
Signed-off-by: Eric Blake <address@hidden>
---
include/block/block_int.h | 4 ++-
block/io.c | 81 +++++++++++++++++++++++++----------------------
2 files changed, 47 insertions(+), 38 deletions(-)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 4282ffd..fa7e3f9 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -165,6 +165,8 @@ struct BlockDriver {
*/
int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
+ int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs,
+ int64_t offset, int count, BdrvRequestFlags flags);
int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors);
int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,
@@ -454,7 +456,7 @@ struct BlockDriverState {
unsigned int request_alignment;
/* Flags honored during pwrite (so far: BDRV_REQ_FUA) */
unsigned int supported_write_flags;
- /* Flags honored during write_zeroes (so far: BDRV_REQ_FUA,
+ /* Flags honored during pwrite_zeroes (so far: BDRV_REQ_FUA,
* BDRV_REQ_MAY_UNMAP) */
unsigned int supported_zero_flags;
diff --git a/block/io.c b/block/io.c
index 41b4e9d..c1d700b 100644
--- a/block/io.c
+++ b/block/io.c
@@ -42,8 +42,8 @@ static BlockAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
void *opaque,
bool is_write);
static void coroutine_fn bdrv_co_do_rw(void *opaque);
-static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
+static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
+ int64_t offset, int count, BdrvRequestFlags flags);
static void bdrv_parent_drained_begin(BlockDriverState *bs)
{
@@ -876,10 +876,12 @@ static int coroutine_fn
bdrv_co_do_copy_on_readv(BlockDriverState *bs,
goto err;
}
- if (drv->bdrv_co_write_zeroes &&
+ if ((drv->bdrv_co_write_zeroes || drv->bdrv_co_pwrite_zeroes) &&
buffer_is_zero(bounce_buffer, iov.iov_len)) {
- ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,
- cluster_nb_sectors, 0);
+ ret = bdrv_co_do_pwrite_zeroes(bs,
+ cluster_sector_num * BDRV_SECTOR_SIZE,
+ cluster_nb_sectors * BDRV_SECTOR_SIZE,
+ 0);
} else {
/* This does not change the data on the disk, it is not necessary
* to flush even in cache=writethrough mode.
@@ -1111,8 +1113,8 @@ int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState
*bs,
#define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768
-static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
+static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
+ int64_t offset, int count, BdrvRequestFlags flags)
{
BlockDriver *drv = bs->drv;
QEMUIOVector qiov;
@@ -1121,40 +1123,45 @@ static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState *bs,
bool need_flush = false;
int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_pwrite_zeroes, INT_MAX);
- int max_write_zeroes_sectors = max_write_zeroes >> BDRV_SECTOR_BITS;
- int write_zeroes_sector_align =
- bs->bl.pwrite_zeroes_alignment >> BDRV_SECTOR_BITS;
+ int alignment = MAX(bs->bl.pwrite_zeroes_alignment, BDRV_SECTOR_SIZE);
- assert(nb_sectors <= BDRV_REQUEST_MAX_SECTORS);
- while (nb_sectors > 0 && !ret) {
- int num = nb_sectors;
+ while (count > 0 && !ret) {
+ int num = count;
/* Align request. Block drivers can expect the "bulk" of the request
* to be aligned.
*/
- if (write_zeroes_sector_align
- && num > write_zeroes_sector_align) {
- if (sector_num % write_zeroes_sector_align != 0) {
+ if (count > alignment) {
+ if (offset % alignment) {
/* Make a small request up to the first aligned sector. */
- num = write_zeroes_sector_align;
- num -= sector_num % write_zeroes_sector_align;
- } else if ((sector_num + num) % write_zeroes_sector_align != 0) {
+ num = alignment - (offset % alignment);
+ } else if ((offset + count) % alignment) {
/* Shorten the request to the last aligned sector. num cannot
- * underflow because num > write_zeroes_sector_align.
+ * underflow because num > alignment.
*/
- num -= (sector_num + num) % write_zeroes_sector_align;
+ num -= (offset + num) % alignment;
}
}
/* limit request size */
- if (num > max_write_zeroes_sectors) {
- num = max_write_zeroes_sectors;
+ if (num > max_write_zeroes) {
+ num = max_write_zeroes;
}
ret = -ENOTSUP;
/* First try the efficient write zeroes operation */
- if (drv->bdrv_co_write_zeroes) {
- ret = drv->bdrv_co_write_zeroes(bs, sector_num, num,
+ if (drv->bdrv_co_pwrite_zeroes) {
+ ret = drv->bdrv_co_pwrite_zeroes(bs, offset, num,
+ flags & bs->supported_zero_flags);
+ if (ret != -ENOTSUP && (flags & BDRV_REQ_FUA) &&
+ !(bs->supported_zero_flags & BDRV_REQ_FUA)) {
+ need_flush = true;
+ }
+ } else if (drv->bdrv_co_write_zeroes) {
+ assert(offset % BDRV_SECTOR_SIZE == 0);
+ assert(count % BDRV_SECTOR_SIZE == 0);
+ ret = drv->bdrv_co_write_zeroes(bs, offset >> BDRV_SECTOR_BITS,
+ num >> BDRV_SECTOR_BITS,
flags & bs->supported_zero_flags);
if (ret != -ENOTSUP && (flags & BDRV_REQ_FUA) &&
!(bs->supported_zero_flags & BDRV_REQ_FUA)) {
@@ -1177,33 +1184,31 @@ static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState *bs,
write_flags &= ~BDRV_REQ_FUA;
need_flush = true;
}
- num = MIN(num, max_xfer_len);
- iov.iov_len = num * BDRV_SECTOR_SIZE;
+ num = MIN(num, max_xfer_len << BDRV_SECTOR_BITS);
+ iov.iov_len = num;
if (iov.iov_base == NULL) {
- iov.iov_base = qemu_try_blockalign(bs, num * BDRV_SECTOR_SIZE);
+ iov.iov_base = qemu_try_blockalign(bs, num);
if (iov.iov_base == NULL) {
ret = -ENOMEM;
goto fail;
}
- memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE);
+ memset(iov.iov_base, 0, num);
}
qemu_iovec_init_external(&qiov, &iov, 1);
- ret = bdrv_driver_pwritev(bs, sector_num * BDRV_SECTOR_SIZE,
- num * BDRV_SECTOR_SIZE, &qiov,
- write_flags);
+ ret = bdrv_driver_pwritev(bs, offset, num, &qiov, write_flags);
/* Keep bounce buffer around if it is big enough for all
* all future requests.
*/
- if (num < max_xfer_len) {
+ if (num < max_xfer_len << BDRV_SECTOR_BITS) {
qemu_vfree(iov.iov_base);
iov.iov_base = NULL;
}
}
- sector_num += num;
- nb_sectors -= num;
+ offset += num;
+ count -= num;
}
fail:
@@ -1241,7 +1246,8 @@ static int coroutine_fn
bdrv_aligned_pwritev(BlockDriverState *bs,
ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req);
if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
- !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_write_zeroes &&
+ !(flags & BDRV_REQ_ZERO_WRITE) &&
+ (drv->bdrv_co_pwrite_zeroes || drv->bdrv_co_write_zeroes) &&
qemu_iovec_is_zero(qiov)) {
flags |= BDRV_REQ_ZERO_WRITE;
if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
@@ -1253,7 +1259,8 @@ static int coroutine_fn
bdrv_aligned_pwritev(BlockDriverState *bs,
/* Do nothing, write notifier decided to fail this request */
} else if (flags & BDRV_REQ_ZERO_WRITE) {
bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
- ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);
+ ret = bdrv_co_do_pwrite_zeroes(bs, sector_num << BDRV_SECTOR_BITS,
+ nb_sectors << BDRV_SECTOR_BITS, flags);
} else {
bdrv_debug_event(bs, BLKDBG_PWRITEV);
ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, flags);
--
2.5.5
- [Qemu-block] [PATCH 00/13] Kill sector-based write_zeroes, Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 12/13] vmdk: Convert to bdrv_co_pwrite_zeroes(), Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 10/13] raw-posix: Convert to bdrv_co_pwrite_zeroes(), Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 03/13] block: Add .bdrv_co_pwrite_zeroes(),
Eric Blake <=
- [Qemu-block] [PATCH 04/13] block: Switch bdrv_write_zeroes() to byte interface, Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 08/13] gluster: Convert to bdrv_co_pwrite_zeroes(), Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 01/13] block: Rename blk_write_zeroes(), Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 13/13] block: Kill bdrv_co_write_zeroes(), Eric Blake, 2016/05/24
- [Qemu-block] [PATCH 11/13] raw_bsd: Convert to bdrv_co_pwrite_zeroes(), Eric Blake, 2016/05/24