From 3d69435ee3292b4b1db2d61c4784789d75883821 Mon Sep 17 00:00:00 2001
From: Dimitri John Ledkov <xnox@ubuntu.com>
Date: Tue, 26 Jul 2016 13:24:39 +0100
Subject: Imported Upstream version 4.6.1

---
 Documentation/btrfs-select-super.asciidoc | 47 +++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 Documentation/btrfs-select-super.asciidoc

(limited to 'Documentation/btrfs-select-super.asciidoc')

diff --git a/Documentation/btrfs-select-super.asciidoc b/Documentation/btrfs-select-super.asciidoc
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+btrfs-select-super(8)
+=====================
+
+NAME
+----
+btrfs-select-super - overwrite primary superblock with a backup copy
+
+SYNOPSIS
+--------
+*btrfs-select-super* -s number <device>
+
+DESCRIPTION
+-----------
+Destructively overwrite all copies of the superblock
+with a specified copy.  This helps in certain cases, for example when write
+barriers were disabled during a power failure and not all superblocks were
+written, or if the primary superblock is damaged, eg. accidentally overwritten.
+
+The filesystem specified by 'device' must not be mounted.
+
+NOTE: *Prior to overwriting the primary superblock, please make sure that the backup
+copies are valid!*
+
+To dump a superblock use the *btrfs inspect-internal
+dump-super* command, or the obsolete command *btrfs-show-super*.
+
+Then run the check (in the non-repair mode) using the command *btrfs check -s*
+where '-s' specifies the superblock copy to use.
+
+Superblock copies exist in the following offsets on the device:
+
+- primary: '64KiB' (65536)
+- 1st copy: '64MiB' (67108864)
+- 2nd copy: '256GiB' (274877906944)
+
+A superblock size is '4KiB' (4096).
+
+OPTIONS
+-------
+-s|--super <superblock>::
+use 'superblock'th superblock copy, valid values are 0 1 or 2 if the
+respective superblock offset is within the device size
+
+SEE ALSO
+--------
+`btrfs-inspect-internal`(8),
+`btrfsck check`(8)
-- 
cgit v1.2.3

