btrfs-zero-log(8)
=================

NAME
----
btrfs-zero-log - clear out log tree

SYNOPSIS
--------
*btrfs-zero-log* <dev>

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.

SEE ALSO
--------
`mkfs.btrfs`(8)
