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Differences from btrfs-progs

btrfsutils aims to be a drop-in replacement for btrfs-progs. Most commands produce identical output and accept the same flags. This page lists the known gaps and the features that go beyond what btrfs-progs offers.

What’s not yet supported

These features from btrfs-progs are not yet implemented:

  • btrfs check --repair and related write-mode flags (--init-csum-tree, --init-extent-tree, etc.). Read-only checking works.
  • btrfs check --mode lowmem (currently only the default mode is supported).
  • btrfs balance start --background daemonize path; balance runs in the foreground.
  • btrfs filesystem resize --offline.
  • btrfs-mkfs zoned device support.

What’s added beyond btrfs-progs

These features are original additions not present in the C tools:

  • --format modern (or BTRFS_OUTPUT_FORMAT=modern): opt-in improved output with adaptive column widths and tree views. Supported by most tabular commands including device stats, device usage, subvolume list, inspect list-chunks, filesystem du/df/show/usage, qgroup show, quota status, scrub start/status.
  • btrfs filesystem du --depth N: limit display depth while computing full totals.
  • btrfs filesystem du --sort: sort entries by path, total, exclusive, or shared.
  • btrfs inspect list-chunks --offline: read chunks directly from an unmounted device or image file without CAP_SYS_ADMIN.
  • btrfs inspect min-dev-size --offline: compute minimum device size from an unmounted device or image file.
  • btrfs device stats --offline: read device error statistics from the on-disk device tree without requiring a mounted filesystem.
  • btrfs send --offline IMAGE: generate a v1 send stream from an unmounted btrfs image without touching the kernel ioctl. No CAP_SYS_ADMIN, no mount needed. Tier 1 (full sends only).
  • btrfs reflink clone [-r SRCOFF:LENGTH:DESTOFF]... SRC DST: lightweight file copy via FICLONERANGE. The btrfs-progs command of the same name is a stub that returns EOPNOTSUPP; ours actually clones.
  • btrfs fuse <IMAGE> <MOUNTPOINT>: mount any btrfs image or block device read-only via FUSE, embedded as a subcommand behind the opt-in fuse cargo feature. Mirrors the standalone btrfs-fuse binary.