1# SPDX-License-Identifier: GPL-2.0-only 2config NILFS2_FS 3 tristate "NILFS2 file system support" 4 select BUFFER_HEAD 5 select CRC32 6 select LEGACY_DIRECT_IO 7 help 8 NILFS2 is a log-structured file system (LFS) supporting continuous 9 snapshotting. In addition to versioning capability of the entire 10 file system, users can even restore files mistakenly overwritten or 11 destroyed just a few seconds ago. Since this file system can keep 12 consistency like conventional LFS, it achieves quick recovery after 13 system crashes. 14 15 NILFS2 creates a number of checkpoints every few seconds or per 16 synchronous write basis (unless there is no change). Users can 17 select significant versions among continuously created checkpoints, 18 and can change them into snapshots which will be preserved for long 19 periods until they are changed back to checkpoints. Each 20 snapshot is mountable as a read-only file system concurrently with 21 its writable mount, and this feature is convenient for online backup. 22 23 Some features including atime, extended attributes, and POSIX ACLs, 24 are not supported yet. 25 26 To compile this file system support as a module, choose M here: the 27 module will be called nilfs2. If unsure, say N. 28