btrfs-progs: docs: clarify scrub requiring mounted filesystem

That scrub works only on a mounted filesystem is not clear in connection
with the possibility to start scrub on a given device. Update the manual
page and mention the mount requirement where approrpriate.

Issue: #335
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2021-01-29 15:12:34 +01:00
parent 911741e854
commit b691968d18

View File

@ -11,9 +11,9 @@ SYNOPSIS
DESCRIPTION
-----------
*btrfs scrub* is used to scrub a btrfs filesystem, which will read all data
and metadata blocks from all devices and verify checksums. Automatically repair
corrupted blocks if there's a correct copy available.
*btrfs scrub* is used to scrub a mounted btrfs filesystem, which will read all
data and metadata blocks from all devices and verify checksums. Automatically
repair corrupted blocks if there's a correct copy available.
NOTE: Scrub is not a filesystem checker (fsck) and does not verify nor repair
structural damage in the filesystem. It really only checks checksums of data
@ -34,6 +34,9 @@ state is communicated through a named pipe in file 'scrub.progress.UUID' in the
same directory.) The status file is updated every 5 seconds. A resumed scrub
will continue from the last saved position.
Scrub can be started only on a mounted filesystem, though it's possible to
scrub only a selected device. See *scrub start* for more.
SUBCOMMAND
----------
*cancel* <path>|<device>::
@ -57,8 +60,9 @@ This does not start a new scrub if the last scrub finished successfully.
see *scrub start*.
*start* [-BdqrRf] [-c <ioprio_class> -n <ioprio_classdata>] <path>|<device>::
Start a scrub on all devices of the filesystem identified by 'path' or on
a single 'device'. If a scrub is already running, the new one will not start.
Start a scrub on all devices of the mounted filesystem identified by 'path' or
on a single 'device'. If a scrub is already running, the new one will not
start. A device of an unmounted filesystem cannot be scrubbed this way.
+
Without options, scrub is started as a background process. The automatic
repairs of damaged copies is performed by default for block group profiles with