mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-04 18:19:28 +09:00
6bb6b51447
When you snapshot a subvolume containing a subvolume, you get a placeholder directory where the subvolume would be. These directories have their own btrfs_dir_ro_inode_operations. Al pointed out [1] that these directories can use simple_lookup() instead of btrfs_lookup(), as they are always empty. Furthermore, they can use the default generic_permission() instead of btrfs_permission(); the additional checks in the latter don't matter because we can't write to the directory anyways. Finally, they can use the default generic_update_time() instead of btrfs_update_time(), as the inode doesn't exist on disk and doesn't need any special handling. All together, this means that we can get rid of btrfs_dir_ro_inode_operations and use simple_dir_inode_operations instead. 1: https://lore.kernel.org/linux-btrfs/20190929052934.GY26530@ZenIV.linux.org.uk/ Cc: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comment ] 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 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.