diff options
| author | Omar Sandoval <osandov@fb.com> | 2016-11-14 10:43:22 -0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-11-23 11:07:05 +0100 |
| commit | 87895ef4da2819b0b3ffde6bcd45abf7b2533b7f (patch) | |
| tree | 67d3e1899a67397bb25cae6a6ea71443717601d5 /Documentation | |
| parent | 981441102199c5c9e3fca84ff3e723ddfa78de01 (diff) | |
btrfs-progs: implement btrfs check --clear-space-cache v2
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
[ adjusted error messages ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/btrfs-check.asciidoc | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/btrfs-check.asciidoc b/Documentation/btrfs-check.asciidoc index 5ef414eb..633cbbf6 100644 --- a/Documentation/btrfs-check.asciidoc +++ b/Documentation/btrfs-check.asciidoc @@ -80,12 +80,16 @@ superblock is damaged. --clear-space-cache v1|v2:: completely wipe all free space cache of given type - -NOTE: Only v1 free space cache supported is implemented. + -Kernel mount option 'clear_cache' is only designed to rebuild free space cache -which is modified during the lifetime of that mount option. It doesn't rebuild -all free space cache, nor clear them out. +For free space cache 'v1', the 'clear_cache' kernel mount option only rebuilds +the free space cache for block groups that are modified while the filesystem is +mounted with that option. Thus, using this option with 'v1' makes it possible +to actually clear the entire free space cache. ++ +For free space cache 'v2', the 'clear_cache' kernel mount option does destroy +the entire free space cache. This option with 'v2' provides an alternative +method of clearing the free space cache that doesn't require mounting the +filesystem. DANGEROUS OPTIONS |