nilfs2: add barrier mount option
Nilfs enables write barriers by default and has "nobarrier" mount
option to disable this feature. But it lacks the complementary option
and has no way to re-enable the feature on remount.
This adds "barrier" option to resolve this imbalance.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt
index d3e7673..54f61c0 100644
--- a/Documentation/filesystems/nilfs2.txt
+++ b/Documentation/filesystems/nilfs2.txt
@@ -49,7 +49,10 @@
NILFS2 supports the following mount options:
(*) == default
-nobarrier Disables barriers.
+barrier(*) This enables/disables the use of write barriers. This
+nobarrier requires an IO stack which can support barriers, and
+ if nilfs gets an error on a barrier write, it will
+ disable again with a warning.
errors=continue Keep going on a filesystem error.
errors=remount-ro(*) Remount the filesystem read-only on an error.
errors=panic Panic and halt the machine if an error occurs.