[PATCH] btrfs-progs: change mans to describe the third copy of superblock

[Satoru Takeuchi <satoru.takeuchi@gmail.com>]

Some tools can select which superblock these commands use by "-s <superblock>"
option. Although this option says the valid values are 0-2, we can set 3
if filesystem is very large.

Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>
---
 Documentation/btrfs-check.asciidoc        | 2 +-
 Documentation/btrfs-restore.asciidoc      | 2 +-
 Documentation/btrfs-select-super.asciidoc | 3 ++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/btrfs-check.asciidoc b/Documentation/btrfs-check.asciidoc
index fbf4884..a557cff 100644
--- a/Documentation/btrfs-check.asciidoc
+++ b/Documentation/btrfs-check.asciidoc
@@ -74,7 +74,7 @@ run in read-only mode, this option exists to calm potential panic when users
 are going to run the checker
 
 -s|--super <superblock>::
-use 'superblock'th superblock copy, valid values are 0, 1 or 2 if the
+use 'superblock'th superblock copy, valid values are 0, 1, 2 or 3 if the
 respective superblock offset is within the device size
 +
 This can be used to use a different starting point if some of the primary
diff --git a/Documentation/btrfs-restore.asciidoc b/Documentation/btrfs-restore.asciidoc
index 090dcc5..c19e0e2 100644
--- a/Documentation/btrfs-restore.asciidoc
+++ b/Documentation/btrfs-restore.asciidoc
@@ -63,7 +63,7 @@ use <bytenr> to read the root tree
 only restore files that are under specified subvolume root pointed by <bytenr>
 
 -u|--super <mirror>::
-use given superblock mirror identified by <mirror>, it can be 0,1 or 2
+use given superblock mirror identified by <mirror>, it can be 0, 1, 2 or 3
 
 -r|--root <rootid>::
 only restore files that are under a specified subvolume whose objectid is <rootid>
diff --git a/Documentation/btrfs-select-super.asciidoc b/Documentation/btrfs-select-super.asciidoc
index 6e94a03..7f96bd8 100644
--- a/Documentation/btrfs-select-super.asciidoc
+++ b/Documentation/btrfs-select-super.asciidoc
@@ -32,13 +32,14 @@ Superblock copies exist in the following offsets on the device:
 - primary: '64KiB' (65536)
 - 1st copy: '64MiB' (67108864)
 - 2nd copy: '256GiB' (274877906944)
+- 3rd copy: '1PiB' (1125899906842624)
 
 A superblock size is '4KiB' (4096).
 
 OPTIONS
 -------
 -s|--super <superblock>::
-use 'superblock'th superblock copy, valid values are 0 1 or 2 if the
+use 'superblock'th superblock copy, valid values are 0, 1, 2 or 3 if the
 respective superblock offset is within the device size
 
 SEE ALSO
-- 
2.7.4