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[PATCH v14 07/13] block: include supported_read_flags into BDS structure
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH v14 07/13] block: include supported_read_flags into BDS structure |
Date: |
Sat, 5 Dec 2020 01:07:52 +0300 |
From: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Add the new member supported_read_flags to the BlockDriverState
structure. It will control the flags set for copy-on-read operations.
Make the block generic layer evaluate supported read flags before they
go to a block driver.
Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
include/block/block_int.h | 4 ++++
block/io.c | 12 ++++++++++--
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index c05fa1eb6b..247e166ab6 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -873,6 +873,10 @@ struct BlockDriverState {
/* I/O Limits */
BlockLimits bl;
+ /*
+ * Flags honored during pread
+ */
+ unsigned int supported_read_flags;
/* Flags honored during pwrite (so far: BDRV_REQ_FUA,
* BDRV_REQ_WRITE_UNCHANGED).
* If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those
diff --git a/block/io.c b/block/io.c
index ec5e152bb7..e28b11c42b 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1405,6 +1405,9 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild
*child,
if (flags & BDRV_REQ_COPY_ON_READ) {
int64_t pnum;
+ /* The flag BDRV_REQ_COPY_ON_READ has reached its addressee */
+ flags &= ~BDRV_REQ_COPY_ON_READ;
+
ret = bdrv_is_allocated(bs, offset, bytes, &pnum);
if (ret < 0) {
goto out;
@@ -1426,9 +1429,13 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild
*child,
goto out;
}
+ if (flags & ~bs->supported_read_flags) {
+ abort();
+ }
+
max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
if (bytes <= max_bytes && bytes <= max_transfer) {
- ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0);
+ ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, flags);
goto out;
}
@@ -1441,7 +1448,8 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild
*child,
ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
num, qiov,
- qiov_offset + bytes - bytes_remaining, 0);
+ qiov_offset + bytes - bytes_remaining,
+ flags);
max_bytes -= num;
} else {
num = bytes_remaining;
--
2.21.3
- [PATCH v14 00/13] Apply COR-filter to the block-stream permanently, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 01/13] copy-on-read: support preadv/pwritev_part functions, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 02/13] block: add API function to insert a node, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 03/13] copy-on-read: add filter drop function, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 04/13] qapi: add filter-node-name to block-stream, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 07/13] block: include supported_read_flags into BDS structure,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v14 06/13] iotests: add #310 to test bottom node in COR driver, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 09/13] stream: skip filters when writing backing file name to QCOW2 header, Vladimir Sementsov-Ogievskiy, 2020/12/04
- [PATCH v14 05/13] qapi: create BlockdevOptionsCor structure for COR driver, Vladimir Sementsov-Ogievskiy, 2020/12/04