Currently, null_blk has 'badblocks' attribute to simulate IO failures for broken blocks. This helps checking if userland tools can handle IO failures. However, this badblocks feature has two differences from the IO failures on real storage devices. Firstly, when write operations fail for the badblocks, null_blk does not write any data, while real storage devices sometimes do partial data write. Secondly, null_blk always make write operations fail for the specified badblocks, while real storage devices can recover the bad blocks so that next write operations can succeed after failure. Hence, real storage devices are required to check if userland tools support such partial writes or bad blocks recovery. This series improves write failure simulation by null_blk to allow checking userland tools without real storage devices. The first patch is a preparation to make new feature addition simpler. The second and the third patches add partial IO support. The last patch introduces 'badblocks_once' attribute to simulate bad blocks recovery. Changes from v1: * Added the first patch which avoids the long, multi-line features string Shin'ichiro Kawasaki (4): null_blk: generate null_blk configfs features string null_blk: do partial IO for bad blocks null_blk: move write pointers for partial writes null_blk: introduce badblocks_once parameter drivers/block/null_blk/main.c | 135 ++++++++++++++++++++---------- drivers/block/null_blk/null_blk.h | 7 ++ drivers/block/null_blk/zoned.c | 10 +++ 3 files changed, 110 insertions(+), 42 deletions(-) -- 2.47.0
