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1# SPDX-License-Identifier: GPL-2.0-only2config NILFS2_FS3 tristate "NILFS2 file system support"4 select BUFFER_HEAD5 select CRC326 select LEGACY_DIRECT_IO7 help8 NILFS2 is a log-structured file system (LFS) supporting continuous9 snapshotting. In addition to versioning capability of the entire10 file system, users can even restore files mistakenly overwritten or11 destroyed just a few seconds ago. Since this file system can keep12 consistency like conventional LFS, it achieves quick recovery after13 system crashes.14 15 NILFS2 creates a number of checkpoints every few seconds or per16 synchronous write basis (unless there is no change). Users can17 select significant versions among continuously created checkpoints,18 and can change them into snapshots which will be preserved for long19 periods until they are changed back to checkpoints. Each20 snapshot is mountable as a read-only file system concurrently with21 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: the27 module will be called nilfs2. If unsure, say N.28