c3a62baf21
The stripes_pending in the btrfs_io_context counts number of inflight low-level bios for an upper btrfs_bio. For reads this is generally one as reads are never cloned, while for writes we can trivially use the bio remaining mechanisms that is used for chained bios. To be able to make use of that mechanism, split out a separate trivial end_io handler for the cloned bios that does a minimal amount of error tracking and which then calls bio_endio on the original bio to transfer control to that, with the remaining counter making sure it is completed last. This then allows to merge btrfs_end_bioc into the original bio bi_end_io handler. To make this all work all error handling needs to happen through the bi_end_io handler, which requires a small amount of reshuffling in submit_stripe_bio so that the bio is cloned already by the time the suitability of the device is checked. This reduces the size of the btrfs_io_context and prepares splitting the btrfs_bio at the stripe boundary. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> 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.