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@xxxxxxxxxxxxx>
---
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 d3e7673..54f61c0 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 29be735..7d77913 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -598,7 +598,7 @@ 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,
};
@@ -606,6 +606,7 @@ 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"},
@@ -631,6 +632,9 @@ 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;
--
1.6.6.2
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