btrfs-zero-log(8) ================= NAME ---- btrfs-zero-log - clear out log tree SYNOPSIS -------- *btrfs-zero-log* DESCRIPTION ----------- *btrfs-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 *btrfs-zero-log* should be used to clear the log and the filesystem may be mounted normally again. NOTE: If you use btrfs as the root filesystem, you may want to include *btrfs-zero-log* into initramdisk if the log problems hits you often. EXIT STATUS ----------- *btrfs-zero-log* will return 0 if no error happened. Other exit code means some problems happened. AUTHOR ------ Written by Shilong Wang and Wenruo Qu. COPYRIGHT --------- Copyright (C) 2013 FUJITSU LIMITED. License GPLv2: GNU GPL version 2 . This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. SEE ALSO -------- `mkfs.btrfs`(8)