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block: include supported_read_flags into BDS structure
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> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [vsementsov: use assert instead of abort] Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201216061703.70908-8-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
parent
b6e0985a4c
commit
897dd0ec4f
10
block/io.c
10
block/io.c
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@ -1453,6 +1453,9 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
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if (flags & BDRV_REQ_COPY_ON_READ) {
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int64_t pnum;
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/* The flag BDRV_REQ_COPY_ON_READ has reached its addressee */
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flags &= ~BDRV_REQ_COPY_ON_READ;
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ret = bdrv_is_allocated(bs, offset, bytes, &pnum);
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if (ret < 0) {
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goto out;
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@ -1474,9 +1477,11 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
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goto out;
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}
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assert(!(flags & ~bs->supported_read_flags));
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max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
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if (bytes <= max_bytes && bytes <= max_transfer) {
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ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0);
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ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, flags);
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goto out;
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}
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@ -1489,7 +1494,8 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
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ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
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num, qiov,
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qiov_offset + bytes - bytes_remaining, 0);
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qiov_offset + bytes - bytes_remaining,
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flags);
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max_bytes -= num;
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} else {
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num = bytes_remaining;
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@ -881,6 +881,10 @@ struct BlockDriverState {
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/* I/O Limits */
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BlockLimits bl;
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/*
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* Flags honored during pread
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*/
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unsigned int supported_read_flags;
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/* Flags honored during pwrite (so far: BDRV_REQ_FUA,
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* BDRV_REQ_WRITE_UNCHANGED).
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* If a driver does not support BDRV_REQ_WRITE_UNCHANGED, those
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