a8c752bb1d
This patch adds backpointers: we now have a reverse index from device and offset on that device (specifically, offset within a bucket) back to btree nodes and (non cached) data extents. The first 40 backpointers within a bucket are stored in the alloc key; after that backpointers spill over to the next backpointers btree. This is to help avoid performance regressions from additional btree updates on large streaming workloads. This patch adds all the code for creating, checking and repairing backpointers. The next patch in the series is going to use backpointers for copygc - finally getting rid of the need to scan all extents to do copygc. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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.