17aaa434ed
To support optional cancellation of some operations, add helper that will wrap all the combinations. In normal mode it's same as btrfs_exclop_start, in cancellation mode it checks if it's already running and request cancellation and waits until completion. The error codes can be returned to to user space and semantics is not changed, adding ECANCELED. This should be evaluated as an error and that the operation has not completed and the operation should be restarted or the filesystem status reviewed. Signed-off-by: David Sterba <dsterba@suse.com>
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.