btrfs-progs/Documentation/btrfs-select-super.rst
David Sterba 4110fbc46f btrfs-progs: docs: add sample RSTified manual page
The asciidoc format needs to be tweaked but otherwise is basically the
same. Changes:

- bold text is ** **
- italics is * *
- NOTE is directive .. note
- definition list is simple indented block after the term
- section NAME in the manual page is generated from date in
  conf.py:man_pages
- new page has to be added to the index

To do:

- references to other manual pages, will be RST native linking once all
  the pages are converted

The output is in Documentation/_build/man and the format is visually not
much different from what is generated by asciidoc.

Signed-off-by: David Sterba <dsterba@suse.com>
2021-10-29 17:30:03 +02:00

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ReStructuredText

btrfs-select-super(8)
=====================
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.
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 <N>
use Nth superblock copy, valid values are 0 1 or 2 if the
respective superblock offset is within the device size
SEE ALSO
--------
btrfs(8)