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Filipe Manana
4f208dcc6b
When doing a NOWAIT direct IO read/write, we allocate a context object (struct btrfs_dio_data) with GFP_NOFS, which can result in blocking waiting for memory allocation (GFP_NOFS is __GFP_RECLAIM | __GFP_IO). This is undesirable for the NOWAIT semantics, so do the allocation with GFP_NOWAIT if we are serving a NOWAIT request and if the allocation fails return -EAGAIN, so that the caller can fallback to a blocking context and retry with a non-blocking write. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@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.