From 773bc4f3b6898634a80a41c72a1f34cb89992dcd Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Date: Mon, 5 Jul 2010 13:00:08 +0900
Subject: [PATCH] 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>
---
Documentation/filesystems/nilfs2.txt | 5 ++++-
fs/nilfs2/super.c | 6 +++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/nilfs2.txt b/Documentation/filesystems/nilfs2.txt
index d3e7673995eb..54f61c0ff442 100644
--- a/Documentation/filesystems/nilfs2.txt
+++ b/Documentation/filesystems/nilfs2.txt
@@ -49,7 +49,10 @@ Mount options
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.
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index f2cfbbab2346..13b0e955c028 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -603,7 +603,7 @@ static const struct export_operations nilfs_export_ops = {
enum {
Opt_err_cont, Opt_err_panic, Opt_err_ro,
- Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
+ Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
Opt_discard, Opt_err,
};
@@ -611,6 +611,7 @@ static match_table_t tokens = {
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
+ {Opt_barrier, "barrier"},
{Opt_nobarrier, "nobarrier"},
{Opt_snapshot, "cp=%u"},
{Opt_order, "order=%s"},
@@ -636,6 +637,9 @@ static int parse_options(char *options, struct super_block *sb)
token = match_token(p, tokens, args);
switch (token) {
+ case Opt_barrier:
+ nilfs_set_opt(sbi, BARRIER);
+ break;
case Opt_nobarrier:
nilfs_clear_opt(sbi, BARRIER);
break;
--
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