mirror of
https://github.com/torvalds/linux.git
synced 2025-12-07 20:06:24 +00:00
2574e90110
Currently btrfs_repair_io_failure() only accept a single @paddr parameter, and for bs > ps cases it's required that @paddr is backed by a large folio. That assumption has quite some limitations, preventing us from utilizing true zero-copy direct-io and encoded read/writes. To address the problem, enhance btrfs_repair_io_failure() by: - Accept an array of paddrs, up to 64K / PAGE_SIZE entries This kind of acts like a bio_vec, but with very limited entries, as the function is only utilized to repair one fs data block, or a tree block. Both have an upper size limit (BTRFS_MAX_BLOCK_SIZE, i.e. 64K), so we don't need the full bio_vec thing to handle it. - Allocate a bio with multiple slots Previously even for bs > ps cases, we only passed in a contiguous physical address range, thus a single slot will be enough. But not anymore, so we have to allocate a bio structure, other than using the on-stack one. - Use on-stack memory to allocate @paddrs array It's at most 16 pages (4K page size, 64K block size), will take up at most 128 bytes. I think the on-stack cost is still acceptable. - Add one extra check to make sure the repair bio is exactly one block - Utilize btrfs_repair_io_failure() to submit a single bio for metadata This should improve the read-repair performance for metadata, as now we submit a node sized bio then wait, other than submit each block of the metadata and wait for each submitted block. - Add one extra parameter indicating the step This is due to the fact that metadata step can be as large as nodesize, instead of sectorsize. So we need a way to distinguish metadata and data repair. - Reduce the width of @length parameter of btrfs_repair_io_failure() Since we only call btrfs_repair_io_failure() on a single data or metadata block, u64 is overkilled. Use u32 instead and add one extra ASSERT()s to make sure the length never exceed BTRFS_MAX_BLOCK_SIZE. Signed-off-by: Qu Wenruo <wqu@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 reStructuredText 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.