aa56b0aa91
run_delalloc_nocow is a little special because we use the file extents to see if we can nocow a range. We don't actually need the protection of the extent lock to look at the file extents at this point however. We are currently holding the page lock for this range, so we are protected from anybody who would simultaneously be modifying the file extent items for this range. * mmap() - we're holding the page lock. * buffered writes - we're holding the page lock. * direct writes - we're holding the page lock and direct IO has to flush page cache before it's able to continue. * fallocate() - all callers flush the range and wait on ordered extents while holding the inode lock and the mmap lock, so we are again saved by the page lock. We want to use the extent lock to protect 1) The mapping tree for the given range. 2) The ordered extents for the given range. 3) The io_tree for the given range. Push the extent lock down to cover these operations. In the fallback_to_cow() case we simply lock before doing anything and rely on the cow_file_range() helper to handle it's range properly. Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> 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 reStructuredText 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.