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| author | Max Reitz | 2019-09-18 11:51:40 +0200 |
|---|---|---|
| committer | Max Reitz | 2019-10-28 12:00:07 +0100 |
| commit | c80d8b06cfa59f5d8229379c85dcb2c3bb9c881b (patch) | |
| tree | 0e30acba1187e0e5ccfaaf6324dc46431b6691af /include/block | |
| parent | block: Do not truncate file node when formatting (diff) | |
| download | qemu-c80d8b06cfa59f5d8229379c85dcb2c3bb9c881b.tar.gz qemu-c80d8b06cfa59f5d8229379c85dcb2c3bb9c881b.tar.xz qemu-c80d8b06cfa59f5d8229379c85dcb2c3bb9c881b.zip | |
block: Add @exact parameter to bdrv_co_truncate()
We have two drivers (iscsi and file-posix) that (in some cases) return
success from their .bdrv_co_truncate() implementation if the block
device is larger than the requested offset, but cannot be shrunk. Some
callers do not want that behavior, so this patch adds a new parameter
that they can use to turn off that behavior.
This patch just adds the parameter and lets the block/io.c and
block/block-backend.c functions pass it around. All other callers
always pass false and none of the implementations evaluate it, so that
this patch does not change existing behavior. Future patches take care
of that.
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190918095144.955-5-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/block.h | 6 | ||||
| -rw-r--r-- | include/block/block_int.h | 17 |
2 files changed, 19 insertions, 4 deletions
diff --git a/include/block/block.h b/include/block/block.h index 89606bd9f8..1df9848e74 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -346,10 +346,10 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, const char *backing_file); void bdrv_refresh_filename(BlockDriverState *bs); -int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, +int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact, PreallocMode prealloc, Error **errp); -int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc, - Error **errp); +int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact, + PreallocMode prealloc, Error **errp); int64_t bdrv_nb_sectors(BlockDriverState *bs); int64_t bdrv_getlength(BlockDriverState *bs); diff --git a/include/block/block_int.h b/include/block/block_int.h index ca4ccac4c1..02dc0034a2 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -334,8 +334,23 @@ struct BlockDriver { * bdrv_parse_filename. */ const char *protocol_name; + + /* + * Truncate @bs to @offset bytes using the given @prealloc mode + * when growing. Modes other than PREALLOC_MODE_OFF should be + * rejected when shrinking @bs. + * + * If @exact is true, @bs must be resized to exactly @offset. + * Otherwise, it is sufficient for @bs (if it is a host block + * device and thus there is no way to resize it) to be at least + * @offset bytes in length. + * + * If @exact is true and this function fails but would succeed + * with @exact = false, it should return -ENOTSUP. + */ int coroutine_fn (*bdrv_co_truncate)(BlockDriverState *bs, int64_t offset, - PreallocMode prealloc, Error **errp); + bool exact, PreallocMode prealloc, + Error **errp); int64_t (*bdrv_getlength)(BlockDriverState *bs); bool has_variable_length; |