nilfs2: add norecovery mount option
This adds "norecovery" mount option which disables temporal write
access to read-only mounts or snapshots during mount/recovery.
Without this option, write access will be even performed for those
types of mounts; the temporal write access is needed to mount root
file system read-only after an unclean shutdown.
This option will be helpful when user wants to prevent any write
access to the device.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Eric Sandeen <sandeen@redhat.com>
diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt
index cbd8779..4949fca 100644
--- a/Documentation/filesystems/nilfs2.txt
+++ b/Documentation/filesystems/nilfs2.txt
@@ -70,6 +70,10 @@
blocks. That means, it is guaranteed that no
overtaking of events occurs in the recovered file
system after a crash.
+norecovery Disable recovery of the filesystem on mount.
+ This disables every write access on the device for
+ read-only mounts or snapshots. This option will fail
+ for r/w mounts on an unclean volume.
NILFS2 usage
============