* [PATCH] btrfs: Add "barrier" option to support "-o remount,barrier"
@ 2013-12-26 6:45 Qu Wenruo
2014-01-02 15:41 ` David Sterba
0 siblings, 1 reply; 3+ messages in thread
From: Qu Wenruo @ 2013-12-26 6:45 UTC (permalink / raw)
To: linux-btrfs
Btrfs can be remounted without barrier, but there is no "barrier" option
so nobody can remount btrfs back with barrier on. Only umount and
mount again can re-enable barrier.(Quite awkward)
Reported-by: Daniel Blueman <daniel@quora.org>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
Documentation/filesystems/btrfs.txt | 6 ++++++
fs/btrfs/super.c | 8 +++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
index 5dd282d..f6f71d6 100644
--- a/Documentation/filesystems/btrfs.txt
+++ b/Documentation/filesystems/btrfs.txt
@@ -51,6 +51,12 @@ Unless otherwise specified, all options default to off.
defrag process. Works best for small files; Not well suited for
large database workloads.
+ barrier
+ Enable the use of block layer write barriers. Write barriers ensure
+ that certain IOs make it through the device cache and are on persistent
+ storage.
+ Barriers are enabled by default.
+
check_int
check_int_data
check_int_print_mask=<value>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index e9c13fb..c8f4aca 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -323,7 +323,7 @@ enum {
Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
Opt_check_integrity, Opt_check_integrity_including_extent_data,
Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
- Opt_commit_interval,
+ Opt_commit_interval, Opt_barrier,
Opt_err,
};
@@ -335,6 +335,7 @@ static match_table_t tokens = {
{Opt_nodatasum, "nodatasum"},
{Opt_nodatacow, "nodatacow"},
{Opt_nobarrier, "nobarrier"},
+ {Opt_barrier, "barrier"},
{Opt_max_inline, "max_inline=%s"},
{Opt_alloc_start, "alloc_start=%s"},
{Opt_thread_pool, "thread_pool=%d"},
@@ -498,6 +499,11 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
btrfs_info(root->fs_info, "turning off barriers");
btrfs_set_opt(info->mount_opt, NOBARRIER);
break;
+ case Opt_barrier:
+ if (btrfs_test_opt(root, NOBARRIER))
+ btrfs_info(root->fs_info, "turning on barriers");
+ btrfs_clear_opt(info->mount_opt, NOBARRIER);
+ break;
case Opt_thread_pool:
ret = match_int(&args[0], &intarg);
if (ret) {
--
1.8.5.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] btrfs: Add "barrier" option to support "-o remount,barrier"
2013-12-26 6:45 [PATCH] btrfs: Add "barrier" option to support "-o remount,barrier" Qu Wenruo
@ 2014-01-02 15:41 ` David Sterba
2014-01-03 0:43 ` Qu Wenruo
0 siblings, 1 reply; 3+ messages in thread
From: David Sterba @ 2014-01-02 15:41 UTC (permalink / raw)
To: Qu Wenruo; +Cc: linux-btrfs
On Thu, Dec 26, 2013 at 02:45:10PM +0800, Qu Wenruo wrote:
> Btrfs can be remounted without barrier, but there is no "barrier" option
> so nobody can remount btrfs back with barrier on. Only umount and
> mount again can re-enable barrier.(Quite awkward)
Ok for adding the mount option.
> Reported-by: Daniel Blueman <daniel@quora.org>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
> Documentation/filesystems/btrfs.txt | 6 ++++++
> fs/btrfs/super.c | 8 +++++++-
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
> index 5dd282d..f6f71d6 100644
> --- a/Documentation/filesystems/btrfs.txt
> +++ b/Documentation/filesystems/btrfs.txt
> @@ -51,6 +51,12 @@ Unless otherwise specified, all options default to off.
> defrag process. Works best for small files; Not well suited for
> large database workloads.
>
> + barrier
> + Enable the use of block layer write barriers. Write barriers ensure
> + that certain IOs make it through the device cache and are on persistent
> + storage.
> + Barriers are enabled by default.
There's the 'nobarrier' option already, I think it's better to keep the
pairing option documentation at one place and mark the default one with (*).
Related to that, there should imho be a pairing option for every mount
option where it makes sense, so all the combinations work through
remount.
The defaults do not need to be listed via btrfs_show_options, ie. keep
the output same as it is now.
david
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] btrfs: Add "barrier" option to support "-o remount,barrier"
2014-01-02 15:41 ` David Sterba
@ 2014-01-03 0:43 ` Qu Wenruo
0 siblings, 0 replies; 3+ messages in thread
From: Qu Wenruo @ 2014-01-03 0:43 UTC (permalink / raw)
To: dsterba, linux-btrfs
On Thu, 2 Jan 2014 16:41:03 +0100, David Sterba wrote:
> On Thu, Dec 26, 2013 at 02:45:10PM +0800, Qu Wenruo wrote:
>> Btrfs can be remounted without barrier, but there is no "barrier" option
>> so nobody can remount btrfs back with barrier on. Only umount and
>> mount again can re-enable barrier.(Quite awkward)
> Ok for adding the mount option.
>
>> Reported-by: Daniel Blueman <daniel@quora.org>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> ---
>> Documentation/filesystems/btrfs.txt | 6 ++++++
>> fs/btrfs/super.c | 8 +++++++-
>> 2 files changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
>> index 5dd282d..f6f71d6 100644
>> --- a/Documentation/filesystems/btrfs.txt
>> +++ b/Documentation/filesystems/btrfs.txt
>> @@ -51,6 +51,12 @@ Unless otherwise specified, all options default to off.
>> defrag process. Works best for small files; Not well suited for
>> large database workloads.
>>
>> + barrier
>> + Enable the use of block layer write barriers. Write barriers ensure
>> + that certain IOs make it through the device cache and are on persistent
>> + storage.
>> + Barriers are enabled by default.
> There's the 'nobarrier' option already, I think it's better to keep the
> pairing option documentation at one place and mark the default one with (*).
>
> Related to that, there should imho be a pairing option for every mount
> option where it makes sense, so all the combinations work through
> remount.
>
> The defaults do not need to be listed via btrfs_show_options, ie. keep
> the output same as it is now.
>
>
> david
>
Thanks for pointing out these problem.
This makes sense.Like space_cache and nospace_cache follows the way you
mentioned,
but most other options just followed the alphabet order, and a lot of
pairing is missing.
I'll try to add all the missingpairing and unify mount options in the
document.
Qu
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-12-26 6:45 [PATCH] btrfs: Add "barrier" option to support "-o remount,barrier" Qu Wenruo
2014-01-02 15:41 ` David Sterba
2014-01-03 0:43 ` Qu Wenruo
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