3e44f325f6
REQ_OP_FLUSH is only for internal use in the blk-mq and request based drivers. File systems and other block layer consumers must use REQ_OP_WRITE | REQ_PREFLUSH as documented in Documentation/block/writeback_cache_control.rst. While REQ_OP_FLUSH appears to work for blk-mq drivers it does not get the proper flush state machine handling, and completely fails for any bio based drivers, including all the stacking drivers. The block layer will also get a check in 6.8 to reject this use case entirely. [Note: completely untested, but as this never got fixed since the original bug report in November: https://bugzilla.kernel.org/show_bug.cgi?id=218184 and the the discussion in December: https://lore.kernel.org/all/20231221053016.72cqcfg46vxwohcj@moria.home.lan/T/ this seems to be best way to force it] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.