btrfs-check(8) ============== NAME ---- btrfs-rescue - Recover a damaged btrfs filesystem SYNOPSIS -------- *btrfs rescue* DESCRIPTION ----------- *btrfs rescue* is used to try to recover a damaged btrfs filesystem. SUBCOMMAND ---------- *chunk-recover* [options] :: Recover the chunk tree by scanning the devices + `Options` + -y:::: assume an answer of 'yes' to all questions. -v:::: verbose mode. -h:::: help. NOTE: Since *chunk-recover* will scan the whole device, it will be *VERY* slow especially executed on a large device. *super-recover* [options] :: Recover bad superblocks from good copies. + `Options` + -y:::: assume an answer of 'yes' to all questions. -v:::: verbose mode. *zero-log* :: clear out log tree *btrfs rescue zero-log* will remove the log tree if log tree is corrupt, which will allow you to mount the filesystem again. The common case where this happens has been fixed a long time ago, so it is unlikely that you will see this particular problem. One can determine whether *btrfs-zero-log* is needed according to the kernel backtrace: ---- ? replay_one_dir_item+0xb5/0xb5 [btrfs] ? walk_log_tree+0x9c/0x19d [btrfs] ? btrfs_read_fs_root_no_radix+0x169/0x1a1 [btrfs] ? btrfs_recover_log_trees+0x195/0x29c [btrfs] ? replay_one_dir_item+0xb5/0xb5 [btrfs] ? btree_read_extent_buffer_pages+0x76/0xbc [btrfs] ? open_ctree+0xff6/0x132c [btrfs] ---- If the errors are like above, then *zero-log* could be used to clear the log and the filesystem may be mounted normally again. EXIT STATUS ----------- *btrfs rescue* returns a zero exit status if it succeeds. Non zero is returned in case of failure. AVAILABILITY ------------ *btrfs* is part of btrfs-progs. Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for further details. SEE ALSO -------- `mkfs.btrfs`(8), `btrfs-scrub`(8), `btrfs-check`(8)