b6735eff2a
[ Upstream commit 898793d992c23dac6126a6a94ad893eae1a2c9df ] cow_file_range() works in an all-or-nothing way: if it fails to allocate an extent for a part of the given region, it gives up all the region including the successfully allocated parts. On cow_file_range(), run_delalloc_zoned() writes data for the region only when it successfully allocate all the region. This all-or-nothing allocation and write-out are problematic when available space in all the block groups are get tight with the active zone restriction. btrfs_reserve_extent() try hard to utilize the left space in the active block groups and gives up finally and fails with -ENOSPC. However, if we send IOs for the successfully allocated region, we can finish a zone and can continue on the rest of the allocation on a newly allocated block group. This patch implements the partial write-out for run_delalloc_zoned(). With this patch applied, cow_file_range() returns -EAGAIN to tell the caller to do something to progress the further allocation, and tells the successfully allocated region with done_offset. Furthermore, the zoned extent allocator returns -EAGAIN to tell cow_file_range() going back to the caller side. Actually, we still need to wait for an IO to complete to continue the allocation. The next patch implements that part. CC: stable@vger.kernel.org # 5.16+ Fixes: afba2bc036b0 ("btrfs: zoned: implement active zone tracking") 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.