c5ef5c6c73
__extent_writepage_io() function originally just iterates through all the extent maps of a page, and submits any regular extents. This is fine for sectorsize == PAGE_SIZE case, as if a page is dirty, we need to submit the only sector contained in the page. But for subpage case, one dirty page can contain several clean sectors with at least one dirty sector. If __extent_writepage_io() still submit all regular extent maps, it can submit data which is already written to disk. And since such already written data won't have corresponding ordered extents, it will trigger a BUG_ON() in btrfs_csum_one_bio(). Change the behavior of __extent_writepage_io() by finding the first dirty byte in the page, and only submit the dirty range other than the full extent. Since we're also here, also modify the following calls to be subpage compatible: - SetPageError() - end_page_writeback() Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64] Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64] Signed-off-by: Qu Wenruo <wqu@suse.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 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.