40971f2e52
[ Upstream commit 95ecbd0f162fc06ef4c4045a66f653f47b62a2d3 ] Commit b2b0a5e97855 switched from generic_writepages() to filemap_fdatawrite_wbc() in gfs2_ail1_start_one() on the path to replacing ->writepage() with ->writepages() and eventually eliminating the former. Function gfs2_ail1_start_one() is called from gfs2_log_flush(), our main function for flushing the filesystem log. Unfortunately, at least as implemented today, ->writepage() and ->writepages() are entirely different operations for journaled data inodes: while the former creates and submits transactions covering the data to be written, the latter flushes dirty buffers out to disk. With gfs2_ail1_start_one() now calling ->writepages(), we end up creating filesystem transactions while we are in the course of a log flush, which immediately deadlocks on the sdp->sd_log_flush_lock semaphore. Work around that by going back to how things used to work before commit b2b0a5e97855 for now; figuring out a superior solution will take time we don't have available right now. However ... Since the removal of generic_writepages() is imminent, open-code it here. We're already inside a blk_start_plug() ... blk_finish_plug() section here, so skip that part of the original generic_writepages(). This reverts commit b2b0a5e978552e348f85ad9c7568b630a5ede659. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.