usage: btrfs check [options] Check structural integrity of a filesystem (unmounted). Check structural integrity of an unmounted filesystem. Verify internal trees' consistency and item connectivity. In the repair mode try to fix the problems found. WARNING: the repair mode is considered dangerous and should not be used without prior analysis of problems found on the filesystem. Starting point selection: -s, --super NUMBER use this superblock copy -b, --backup use the first valid backup root copy -r, --tree-root use the given bytenr for the tree root --chunk-root BYTENR use the given bytenr for the chunk tree root Operation modes: --readonly run in read-only mode (default) --repair try to repair the filesystem (dangerous, see above warning) --force skip mount checks, recommended only with --readonly; WARNING: it is possible to run with --repair but on a mounted filesystem that will most likely lead to a corruption unless the filesystem is quiescent in a quiescent state which may not be possible to guarantee --mode MODE allows choice of memory/IO trade-offs where MODE is one of: original - read inodes and extents to memory (requires more memory, does less IO) lowmem - try to use less memory but read blocks again when needed Repair options: --init-csum-tree create a new CRC tree --init-extent-tree create a new extent tree Check and reporting options: --check-data-csum verify checksums of data blocks --skip-qgroup-accounting skip quota group accounting verification -Q, --qgroup-report print a report on qgroup consistency -E, --subvol-extents SUBVOLID print subvolume extents and sharing state -p, --progress indicate progress Deprecated or moved options: --clear-space-cache v1|v2 clear space cache for v1 or v2 (moved to 'rescue' group)