deb78b419d
Software must flush disk cache to guarantee data safety. To check if software correctly does disk cache flush, we must know the behavior of disk. But physical disk behavior is uncontrollable. Even software doesn't do the flush, the disk probably does the flush. This patch tries to emulate a cache in the test disk. All write will go to a cache first, when the cache is full, we then flush some data to disk storage. A flush request will flush all data of the cache to disk storage. A FUA write will write to memory store directly and revalidate data in cache. If there is a power failure (by writing to power attribute, 'echo 0 > disk_name/power'), we discard all data in the cache, but preserve the data in disk storage. Later we can power on the disk again as usual (write 1 to 'power' attribute), then we can check data integrity and very if software does everything correctly. A new attribute 'cache_size' (in MB) is added to configure cache size. Based on original patch from Kyungchan Koh Signed-off-by: Kyungchan Koh <kkc6196@fb.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.