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178231af2b
We currently use a btree walk in the fstrim code. This requires a btree cursor and btree cursors are only used inside transactions except for the fstrim code. This means that all the btree operations that allocate memory operate in both GFP_KERNEL and GFP_NOFS contexts. This causes problems with lockdep being unable to determine the difference between objects that are safe to lock both above and below memory reclaim. Free space btree buffers are definitely locked both above and below reclaim and that means we have to mark all btree infrastructure allocations with GFP_NOFS to avoid potential lockdep false positives. If we wrap this btree walk in an empty cursor, all btree walks are now done under transaction context and so all allocations inherit GFP_NOFS context from the tranaction. This enables us to move all the btree allocations to GFP_KERNEL context and hence help remove the explicit use of GFP_NOFS in XFS. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@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.