047487c947
Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
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.