path: root/Documentation/btrfs-check.asciidoc
diff options
authorDimitri John Ledkov <>2017-10-18 13:15:59 +0100
committerDimitri John Ledkov <>2017-10-18 13:15:59 +0100
commit74d288e05c2d0cb97186f51049813b3e5b5bb0cd (patch)
tree4fc213398dc89e053d53ff7d42102942470e9cb5 /Documentation/btrfs-check.asciidoc
parent569a646293cd782de7665b6158514f3b48d229d3 (diff)
New upstream release.
Diffstat (limited to 'Documentation/btrfs-check.asciidoc')
1 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/btrfs-check.asciidoc b/Documentation/btrfs-check.asciidoc
index 28ed9dd7..fbf48847 100644
--- a/Documentation/btrfs-check.asciidoc
+++ b/Documentation/btrfs-check.asciidoc
@@ -3,7 +3,7 @@ btrfs-check(8)
-btrfs-check - check or repair an unmounted btrfs filesystem
+btrfs-check - check or repair a btrfs filesystem
@@ -13,7 +13,9 @@ DESCRIPTION
The filesystem checker is used to verify structural integrity of a filesystem
-and attempt to repair it if requested. The filesystem must be unmounted.
+and attempt to repair it if requested. It is recommended to unmount the
+filesystem prior to running the check, but it is possible to start checking a
+mounted filesystem (see '--force').
By default, *btrfs check* will not modify the device but you can reaffirm that
by the option '--readonly'.
@@ -60,7 +62,7 @@ show extent state for the given subvolume
indicate progress at various checking phases
verify qgroup accounting and compare against filesystem accounting
-r|--tree-root <bytenr>::
@@ -120,6 +122,12 @@ needs to re-read blocks when needed. This may increase run time.
NOTE: 'lowmem' mode does not work with '--repair' yet, and is still considered
+allow to work on a mounted filesystem. Note that this should work fine on a
+quiescent or read-only mounted filesystem but may crash if the device is
+changed externally, eg. by the kernel module. Repair without mount checks is
+not supported right now.
*btrfs check* returns a zero exit status if it succeeds. Non zero is