diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2018-07-25 13:20:32 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2018-07-30 15:35:37 +0200 |
| commit | 52ebcb268273de217510bc9ed688c23894ae32a2 (patch) | |
| tree | 87df452573976d56972e5f730f4e833990c73d2a /include | |
| parent | 8ba4f10fa689251facd483c3ee0ef4dd4e9bec53 (diff) | |
block: Fix documentation for BDRV_REQ_MAY_UNMAP
BDRV_REQ_MAY_UNMAP in a write_zeroes request does not only allow the
driver to unmap the blocks, but it actively requests that the blocks be
unmapped afterwards if at all possible.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/block/block.h | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/include/block/block.h b/include/block/block.h index f85e3a6ed3..4e0871aaf9 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -43,11 +43,12 @@ typedef struct BlockFragInfo { typedef enum { BDRV_REQ_COPY_ON_READ = 0x1, BDRV_REQ_ZERO_WRITE = 0x2, - /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver - * is allowed to optimize a write zeroes request by unmapping (discarding) - * blocks if it is guaranteed that the result will read back as - * zeroes. The flag is only passed to the driver if the block device is - * opened with BDRV_O_UNMAP. + + /* + * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate + * that the block driver should unmap (discard) blocks if it is guaranteed + * that the result will read back as zeroes. The flag is only passed to the + * driver if the block device is opened with BDRV_O_UNMAP. */ BDRV_REQ_MAY_UNMAP = 0x4, |