fe3e397668
The current log space allocation logic is hard to understand or extend. The principle it that when the log is flushed, we may or may not have a transaction active that has space allocated in the log. To deal with that, we set aside a magical number of blocks to be used in case we don't have an active transaction. It isn't clear that the pool will always be big enough. In addition, we can't return unused log space at the end of a transaction, so the number of blocks allocated must exactly match the number of blocks used. Simplify this as follows: * When transactions are allocated or merged, always reserve enough blocks to flush the transaction (err on the safe side). * In gfs2_log_flush, return any allocated blocks that haven't been used. * Maintain a pool of spare blocks big enough to do one log flush, as before. * In gfs2_log_flush, when we have no active transaction, allocate a suitable number of blocks. For that, use the spare pool when called from logd, and leave the pool alone otherwise. This means that when the log is almost full, logd will still be able to do one more log flush, which will result in more log space becoming available. This will make the log space allocator code easier to work with in the future. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.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.