142fbad314
[ Upstream commit 7561551e7ba870b9659083b95feb520fb2dacce3 ] Currently we allow a block group not to be marked read-only for scrub. But for RAID56 block groups if we require the block group to be read-only, then we're allowed to use cached content from scrub stripe to reduce unnecessary RAID56 reads. So this patch would: - Make btrfs_inc_block_group_ro() try harder During my tests, for cases like btrfs/061 and btrfs/064, we can hit ENOSPC from btrfs_inc_block_group_ro() calls during scrub. The reason is if we only have one single data chunk, and trying to scrub it, we won't have any space left for any newer data writes. But this check should be done by the caller, especially for scrub cases we only temporarily mark the chunk read-only. And newer data writes would always try to allocate a new data chunk when needed. - Return error for scrub if we failed to mark a RAID56 chunk read-only Signed-off-by: Qu Wenruo <wqu@suse.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.