f6ad412c64
[ Upstream commit 393f646e34c18b85d0f41272bfcbd475ae3a0d34 ] When we run out of active zones and no sufficient space is left in any block groups, we need to finish one block group to make room to activate a new block group. However, we cannot do this for metadata block groups because we can cause a deadlock by waiting for a running transaction commit. So, do that only for a data block group. Furthermore, the block group to be finished has two requirements. First, the block group must not have reserved bytes left. Having reserved bytes means we have an allocated region but did not yet send bios for it. If that region is allocated by the thread calling btrfs_zone_finish(), it results in a deadlock. Second, the block group to be finished must not be a SYSTEM block group. Finishing a SYSTEM block group easily breaks further chunk allocation by nullifying the SYSTEM free space. In a certain case, we cannot find any zone finish candidate or btrfs_zone_finish() may fail. In that case, we fall back to split the allocation bytes and fill the last spaces left in the block groups. CC: stable@vger.kernel.org # 5.16+ Fixes: afba2bc036b0 ("btrfs: zoned: implement active zone tracking") Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.