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Qu Wenruo 884b07d0f4 btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors
To support sectorsize < PAGE_SIZE case, we need to take extra care of
extent buffer accessors.

Since sectorsize is smaller than PAGE_SIZE, one page can contain
multiple tree blocks, we must use eb->start to determine the real offset
to read/write for extent buffer accessors.

This patch introduces two helpers to do this:

- get_eb_page_index()
  This is to calculate the index to access extent_buffer::pages.
  It's just a simple wrapper around "start >> PAGE_SHIFT".

  For sectorsize == PAGE_SIZE case, nothing is changed.
  For sectorsize < PAGE_SIZE case, we always get index as 0, and
  the existing page shift also works.

- get_eb_offset_in_page()
  This is to calculate the offset to access extent_buffer::pages.
  This needs to take extent_buffer::start into consideration.

  For sectorsize == PAGE_SIZE case, extent_buffer::start is always
  aligned to PAGE_SIZE, thus adding extent_buffer::start to
  offset_in_page() won't change the result.
  For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives
  us the correct offset to access.

This patch will touch the following parts to cover all extent buffer
accessors:

- BTRFS_SETGET_HEADER_FUNCS()
- read_extent_buffer()
- read_extent_buffer_to_user()
- memcmp_extent_buffer()
- write_extent_buffer_chunk_tree_uuid()
- write_extent_buffer_fsid()
- write_extent_buffer()
- memzero_extent_buffer()
- copy_extent_buffer_full()
- copy_extent_buffer()
- memcpy_extent_buffer()
- memmove_extent_buffer()
- btrfs_get_token_##bits()
- btrfs_get_##bits()
- btrfs_set_token_##bits()
- btrfs_set_##bits()
- generic_bin_search()

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09 19:16:10 +01:00
arch USB fixes for 5.10-rc7 2020-12-06 11:38:36 -08:00
block block-5.10-2020-12-05 2020-12-05 14:45:30 -08:00
certs
crypto
Documentation Networking fixes for 5.10-rc7, including fixes from bpf, netfilter, 2020-12-03 13:10:11 -08:00
drivers Char/Misc driver fixes for 5.10-rc7 2020-12-06 11:48:17 -08:00
fs btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors 2020-12-09 19:16:10 +01:00
include btrfs: calculate inline extent buffer page size based on page size 2020-12-09 19:16:10 +01:00
init Kbuild fixes for v5.10 (2nd) 2020-12-06 10:31:39 -08:00
ipc
kernel A set of updates for the interrupt subsystem: 2020-12-06 11:15:55 -08:00
lib zlib: export S390 symbols for zlib modules 2020-12-06 10:19:07 -08:00
LICENSES
mm mm/mmap.c: fix mmap return value when vma is merged after call_mmap() 2020-12-06 10:19:07 -08:00
net net/sched: act_mpls: ensure LSE is pullable before reading it 2020-12-03 11:13:37 -08:00
samples Tracing fixes for 5.10-rc6 2020-12-01 15:30:18 -08:00
scripts Kbuild fixes for v5.10 (2nd) 2020-12-06 10:31:39 -08:00
security
sound
tools A set of fixes for x86: 2020-12-06 11:22:39 -08:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild
Kconfig
MAINTAINERS A set of updates for the interrupt subsystem: 2020-12-06 11:15:55 -08:00
Makefile Linux 5.10-rc7 2020-12-06 14:25:12 -08:00
README

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.