btrfs-progs: Documentaion: rename to .asciidoc

A few minor benefits:

* editors set highliting according to the extensions
* web access to the git repository (github) renders the .asciidoc
  files:
  * we can link to them from the wiki
  * the files are editable via browser and such editations can be
    submitted for merge easily

Signed-off-by: David Sterba <dsterba@suse.cz>

1 files changed, 45 insertions, 0 deletions

diff --git a/Documentation/btrfs-zero-log.asciidoc b/Documentation/btrfs-zero-log.asciidoc
new file mode 100644
index 00000000..498ecd67
--- /dev/null
+++ b/Documentation/btrfs-zero-log.asciidoc
@@ -0,0 +1,45 @@
+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)