1c11b63eff
The pending chunks list contains chunks that are allocated in the current transaction but haven't been created yet. The pinned chunks list contains chunks that are being released in the current transaction. Both describe chunks that are not reflected on disk as in use but are unavailable just the same. The pending chunks list is anchored by the transaction handle, which means that we need to hold a reference to a transaction when working with the list. The way we use them is by iterating over both lists to perform comparisons on the stripes they describe for each device. This is backwards and requires that we keep a transaction handle open while we're trimming. This patchset adds an extent_io_tree to btrfs_device that maintains the allocation state of the device. Extents are set dirty when chunks are first allocated -- when the extent maps are added to the mapping tree. They're cleared when last removed -- when the extent maps are removed from the mapping tree. This matches the lifespan of the pending and pinned chunks list and allows us to do trims on unallocated space safely without pinning the transaction for what may be a lengthy operation. We can also use this io tree to mark which chunks have already been trimmed so we don't repeat the operation. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Nikolay Borisov <nborisov@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.