a0137082de
- use :file: and :command: - simplify manual page references - add more web links - typo fixes - more cross-references Signed-off-by: David Sterba <dsterba@suse.com>
25 lines
1 KiB
ReStructuredText
25 lines
1 KiB
ReStructuredText
Custom ioctls
|
|
=============
|
|
|
|
Filesystems are usually extended by custom ioctls beyond the standard system
|
|
call interface to let user applications access the advanced features. They're
|
|
low level and the following list gives only an overview of the capabilities or
|
|
a command if available:
|
|
|
|
- reverse lookup, from file offset to inode, as command :command:`btrfs inspect-internal logical-resolve`
|
|
|
|
- resolve inode number to list of names, as command :command:`btrfs inspect-internal inode-resolve`
|
|
|
|
- tree search, given a key range and tree id, lookup and return all b-tree items
|
|
found in that range, basically all metadata at your hand but you need to know
|
|
what to do with them, the ioctl is privileged as it has full access to all
|
|
filesystem metadata
|
|
|
|
- informative, about devices, space allocation or the whole filesystem, many of
|
|
which is also exported in :file:`/sys/fs/btrfs/`
|
|
|
|
- query/set a subset of features on a mounted filesystem
|
|
|
|
Programming documentaion of the ioctls is in the manual page
|
|
:doc:`btrfs-ioctl`.
|