diff options
| author | Manos Pitsidianakis <el13635@mail.ntua.gr> | 2017-07-13 18:30:25 +0300 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2017-09-04 18:31:13 +0200 |
| commit | 5a612c009ee538a3b32c896f9a6c5562a50efe9d (patch) | |
| tree | 9e33b62dd41f222d3712d2adf3ce21145787520e /include/block | |
| parent | 98bfaac788be0ca63d7d010c8d4ba100ff1d8278 (diff) | |
block: pass bdrv_* methods to bs->file by default in block filters
The following functions fail if bs->drv is a filter and does not
implement them:
bdrv_probe_blocksizes
bdrv_probe_geometry
bdrv_truncate
bdrv_has_zero_init
bdrv_get_info
Instead, the call should be passed to bs->file if it exists, to allow
filter drivers to support those methods without implementing them. This
commit makes `drv->is_filter = true` imply that these callbacks will be
forwarded to bs->file by default, so disabling support for these
functions must be done explicitly.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/block_int.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/block/block_int.h b/include/block/block_int.h index 7571c0aaaf..71183cc76e 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -87,7 +87,11 @@ struct BlockDriver { const char *format_name; int instance_size; - /* set to true if the BlockDriver is a block filter */ + /* set to true if the BlockDriver is a block filter. Block filters pass + * certain callbacks that refer to data (see block.c) to their bs->file if + * the driver doesn't implement them. Drivers that do not wish to forward + * must implement them and return -ENOTSUP. + */ bool is_filter; /* for snapshots block filter like Quorum can implement the * following recursive callback. |