Linus Torvalds fd71def6d9 Merge tag 'for-6.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
 "User visible changes:

   - fall back to buffered write if direct io is done on a file that
     requires checksums
      - this avoids a problem with checksum mismatch errors, observed
        e.g. on virtual images when writes to pages under writeback
        cause the checksum mismatch reports
      - this may lead to some performance degradation but currently the
        recommended setup for VM images is to use the NOCOW file
        attribute that also disables checksums

   - fast/realtime zstd levels -15 to -1
      - supported by mount options (compress=zstd:-5) and defrag ioctl
      - improved speed, reduced compression ratio, check the commit for
        sample measurements

   - defrag ioctl extended to accept negative compression levels

   - subpage mode
      - remove warning when subpage mode is used, the feature is now
        reasonably complete and tested
      - in debug mode allow to create 2K b-tree nodes to allow testing
        subpage on x86_64 with 4K pages too

  Performance improvements:

   - in send, better file path caching improves runtime (on sample load
     by -30%)

   - on s390x with hardware zlib support prepare the input buffer in a
     better way to get the best results from the acceleration

   - minor speed improvement in encoded read, avoid memory allocation in
     synchronous mode

  Core:

   - enable stable writes on inodes, replacing manually waiting for
     writeback and allowing to skip that on inodes without checksums

   - add last checks and warnings for out-of-band dirty writes to pages,
     requiring a fixup ("fixup worker"), this should not be necessary
     since 5.8 where get_user_page() and pin_user_pages*() prevent this
      - long history behind that, we'll be happy to remove the whole
        infrastructure in the near future

   - more folio API conversions and preparations for large folio support

   - subpage cleanups and refactoring, split handling of data and
     metadata to allow future support for large folios

   - readpage works as block-by-block, no change for normal mode, this
     is preparation for future subpage updates

   - block group refcount fixes and hardening

   - delayed iput fixes

   - in zoned mode, fix zone activation on filesystem with missing
     devices

  Cleanups:

   - inode parameter cleanups

   - path auto-freeing updates

   - code flow simplifications in send

   - redundant parameter cleanups"

* tag 'for-6.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (164 commits)
  btrfs: zoned: fix zone finishing with missing devices
  btrfs: zoned: fix zone activation with missing devices
  btrfs: remove end_no_trans label from btrfs_log_inode_parent()
  btrfs: simplify condition for logging new dentries at btrfs_log_inode_parent()
  btrfs: remove redundant else statement from btrfs_log_inode_parent()
  btrfs: use memcmp_extent_buffer() at replay_one_extent()
  btrfs: update outdated comment for overwrite_item()
  btrfs: use variables to store extent buffer and slot at overwrite_item()
  btrfs: avoid unnecessary memory allocation and copy at overwrite_item()
  btrfs: don't clobber ret in btrfs_validate_super()
  btrfs: prepare btrfs_page_mkwrite() for large folios
  btrfs: prepare extent_io.c for future large folio support
  btrfs: prepare btrfs_launcher_folio() for large folios support
  btrfs: replace PAGE_SIZE with folio_size for subpage.[ch]
  btrfs: add a size parameter to btrfs_alloc_subpage()
  btrfs: subpage: make btrfs_is_subpage() check against a folio
  btrfs: add extra warning if delayed iput is added when it's not allowed
  btrfs: avoid redundant path slot assignment in btrfs_search_forward()
  btrfs: remove unnecessary btrfs_key local variable in btrfs_search_forward()
  btrfs: simplify the return value handling in search_ioctl()
  ...
2025-03-27 12:51:48 -07:00

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.
Description
Linux kernel source tree
Readme 8.6 GiB
Languages
C 97.1%
Assembly 1%
Shell 0.6%
Rust 0.4%
Python 0.4%
Other 0.3%