[PATCH] btrfs: Add nossd_spread mount option

[PATCH] btrfs: Add nossd_spread mount option

[Howard McLauchlan]

Btrfs has two mount options for SSD optimizations: ssd and ssd_spread.
Presently there is an option to disable all SSD optimizations, but there
isn't an option to disable just ssd_spread.

This patch adds a mount option nossd_spread that disables ssd_spread
only.

Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
---
 fs/btrfs/super.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6e71a2a78363..4c0fcf5b3e7e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -310,10 +310,10 @@ static void btrfs_put_super(struct super_block *sb)
 enum {
 	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
-	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
-	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
-	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
-	Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
+	Opt_nossd, Opt_ssd_spread, Opt_nossd_spread, Opt_thread_pool, Opt_noacl,
+	Opt_compress, Opt_compress_type, Opt_compress_force,
+	Opt_compress_force_type, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
+	Opt_discard, Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 	Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 	Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 	Opt_skip_balance, Opt_check_integrity,
@@ -353,6 +353,7 @@ static const match_table_t tokens = {
 	{Opt_ssd, "ssd"},
 	{Opt_ssd_spread, "ssd_spread"},
 	{Opt_nossd, "nossd"},
+	{Opt_nossd_spread, "nossd_spread"},
 	{Opt_acl, "acl"},
 	{Opt_noacl, "noacl"},
 	{Opt_notreelog, "notreelog"},
@@ -582,6 +583,10 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 			btrfs_clear_and_info(info, SSD_SPREAD,
 					     "not using spread ssd allocation scheme");
 			break;
+		case Opt_nossd_spread:
+			btrfs_clear_and_info(info, SSD_SPREAD,
+					     "not using spread ssd allocation scheme");
+			break;
 		case Opt_barrier:
 			btrfs_clear_and_info(info, NOBARRIER,
 					     "turning on barriers");
-- 
2.14.1

Re: [PATCH] btrfs: Add nossd_spread mount option

[Hans van Kranenburg]

On 02/22/2018 12:31 AM, Howard McLauchlan wrote:
> Btrfs has two mount options for SSD optimizations: ssd and ssd_spread.
> Presently there is an option to disable all SSD optimizations, but there
> isn't an option to disable just ssd_spread.
> 
> This patch adds a mount option nossd_spread that disables ssd_spread
> only.
> 
> Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
> ---
>  fs/btrfs/super.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 6e71a2a78363..4c0fcf5b3e7e 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -310,10 +310,10 @@ static void btrfs_put_super(struct super_block *sb)
>  enum {
>  	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
>  	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
> -	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
> -	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
> -	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
> -	Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
> +	Opt_nossd, Opt_ssd_spread, Opt_nossd_spread, Opt_thread_pool, Opt_noacl,
> +	Opt_compress, Opt_compress_type, Opt_compress_force,
> +	Opt_compress_force_type, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
> +	Opt_discard, Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
>  	Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
>  	Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
>  	Opt_skip_balance, Opt_check_integrity,
> @@ -353,6 +353,7 @@ static const match_table_t tokens = {
>  	{Opt_ssd, "ssd"},
>  	{Opt_ssd_spread, "ssd_spread"},
>  	{Opt_nossd, "nossd"},
> +	{Opt_nossd_spread, "nossd_spread"},
>  	{Opt_acl, "acl"},
>  	{Opt_noacl, "noacl"},
>  	{Opt_notreelog, "notreelog"},

.oO(Why doesn't the enum just have one option per line, so the changelog
is less invasive?)

> @@ -582,6 +583,10 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
>  			btrfs_clear_and_info(info, SSD_SPREAD,
>  					     "not using spread ssd allocation scheme");
>  			break;
> +		case Opt_nossd_spread:
> +			btrfs_clear_and_info(info, SSD_SPREAD,
> +					     "not using spread ssd allocation scheme");
> +			break;
>  		case Opt_barrier:
>  			btrfs_clear_and_info(info, NOBARRIER,
>  					     "turning on barriers");
> 

Related:
* https://www.spinics.net/lists/linux-btrfs/msg64247.html
* https://www.spinics.net/lists/linux-btrfs/msg64277.html
* https://www.spinics.net/lists/linux-btrfs/msg64499.html

Apparently that discussion never resulted in actual changes, so thanks
for continuing it now.

The mount options are a bit weird, because ssd_spread also includes ssd,
but doesn't show it.

I personally don't like all of them at all, and I should really finish
and send my proposal to get them replaced by options that can choose
extent allocator for data and metadata individually (instead of some
setting that changes them both at the same time) because there are
proper real life situations that e.g. benefit from nossd style 'tetris'
data allocator with ssd_spread style 'contiguous' metadata extent allocator.

-- 
Hans van Kranenburg

Re: [PATCH] btrfs: Add nossd_spread mount option

[Howard McLauchlan]

On 02/21/2018 05:20 PM, Hans van Kranenburg wrote:
> On 02/22/2018 12:31 AM, Howard McLauchlan wrote:
>> Btrfs has two mount options for SSD optimizations: ssd and ssd_spread.
>> Presently there is an option to disable all SSD optimizations, but there
>> isn't an option to disable just ssd_spread.
>>
>> This patch adds a mount option nossd_spread that disables ssd_spread
>> only.
>>
>> Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
>> ---
>>  fs/btrfs/super.c | 13 +++++++++----
>>  1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
>> index 6e71a2a78363..4c0fcf5b3e7e 100644
>> --- a/fs/btrfs/super.c
>> +++ b/fs/btrfs/super.c
>> @@ -310,10 +310,10 @@ static void btrfs_put_super(struct super_block *sb)
>>  enum {
>>  	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
>>  	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
>> -	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
>> -	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
>> -	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
>> -	Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
>> +	Opt_nossd, Opt_ssd_spread, Opt_nossd_spread, Opt_thread_pool, Opt_noacl,
>> +	Opt_compress, Opt_compress_type, Opt_compress_force,
>> +	Opt_compress_force_type, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
>> +	Opt_discard, Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
>>  	Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
>>  	Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
>>  	Opt_skip_balance, Opt_check_integrity,
>> @@ -353,6 +353,7 @@ static const match_table_t tokens = {
>>  	{Opt_ssd, "ssd"},
>>  	{Opt_ssd_spread, "ssd_spread"},
>>  	{Opt_nossd, "nossd"},
>> +	{Opt_nossd_spread, "nossd_spread"},
>>  	{Opt_acl, "acl"},
>>  	{Opt_noacl, "noacl"},
>>  	{Opt_notreelog, "notreelog"},
> 
> .oO(Why doesn't the enum just have one option per line, so the changelog
> is less invasive?)
> 
>> @@ -582,6 +583,10 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
>>  			btrfs_clear_and_info(info, SSD_SPREAD,
>>  					     "not using spread ssd allocation scheme");
>>  			break;
>> +		case Opt_nossd_spread:
>> +			btrfs_clear_and_info(info, SSD_SPREAD,
>> +					     "not using spread ssd allocation scheme");
>> +			break;
>>  		case Opt_barrier:
>>  			btrfs_clear_and_info(info, NOBARRIER,
>>  					     "turning on barriers");
>>
> 
> Related:
> * https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dbtrfs_msg64247.html&d=DwIDaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=UA4c4GV4shA70-jKB4kwcF99U6K6bzKVYdicFvu-DtQ&m=oYU5SWdFSoawOXAWRYLqZvvDYpROHFkzMQLlAZEehaU&s=0LRSD37KWUOyo_i9ypRAaZrv7_8R_kJ0yHv9vNoqDB4&e=
> * https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dbtrfs_msg64277.html&d=DwIDaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=UA4c4GV4shA70-jKB4kwcF99U6K6bzKVYdicFvu-DtQ&m=oYU5SWdFSoawOXAWRYLqZvvDYpROHFkzMQLlAZEehaU&s=WB_Fyhm3SDx3XdaE71X6aYRxonuk0Q8Jr4f1ai6K2dI&e=
> * https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dbtrfs_msg64499.html&d=DwIDaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=UA4c4GV4shA70-jKB4kwcF99U6K6bzKVYdicFvu-DtQ&m=oYU5SWdFSoawOXAWRYLqZvvDYpROHFkzMQLlAZEehaU&s=FcKlny0UlOCTWEfvCgEz_QtGnYI20EiDF3weQVKPyDs&e=
> 
> Apparently that discussion never resulted in actual changes, so thanks
> for continuing it now.
> 
> The mount options are a bit weird, because ssd_spread also includes ssd,
> but doesn't show it.
> 
> I personally don't like all of them at all, and I should really finish
> and send my proposal to get them replaced by options that can choose
> extent allocator for data and metadata individually (instead of some
> setting that changes them both at the same time) because there are
> proper real life situations that e.g. benefit from nossd style 'tetris'
> data allocator with ssd_spread style 'contiguous' metadata extent allocator.
> 
I agree; this change is just something very specific that came up in prod for us, so I decided to push a patch for it. 

Re: [PATCH] btrfs: Add nossd_spread mount option

[Josef Bacik]

On Wed, Feb 21, 2018 at 03:31:40PM -0800, Howard McLauchlan wrote:
> Btrfs has two mount options for SSD optimizations: ssd and ssd_spread.
> Presently there is an option to disable all SSD optimizations, but there
> isn't an option to disable just ssd_spread.
> 
> This patch adds a mount option nossd_spread that disables ssd_spread
> only.
> 
> Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>

Reviewed-by: Josef Bacik <jbacik@fb.com>

Thanks,

Josef

Re: [PATCH] btrfs: Add nossd_spread mount option

[David Sterba]

On Wed, Feb 21, 2018 at 03:31:40PM -0800, Howard McLauchlan wrote:
> Btrfs has two mount options for SSD optimizations: ssd and ssd_spread.
> Presently there is an option to disable all SSD optimizations, but there
> isn't an option to disable just ssd_spread.
> 
> This patch adds a mount option nossd_spread that disables ssd_spread
> only.
> 
> Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
> ---
>  fs/btrfs/super.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 6e71a2a78363..4c0fcf5b3e7e 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -310,10 +310,10 @@ static void btrfs_put_super(struct super_block *sb)
>  enum {
>  	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
>  	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
> -	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
> -	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
> -	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
> -	Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
> +	Opt_nossd, Opt_ssd_spread, Opt_nossd_spread, Opt_thread_pool, Opt_noacl,
> +	Opt_compress, Opt_compress_type, Opt_compress_force,
> +	Opt_compress_force_type, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
> +	Opt_discard, Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
>  	Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
>  	Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
>  	Opt_skip_balance, Opt_check_integrity,
> @@ -353,6 +353,7 @@ static const match_table_t tokens = {
>  	{Opt_ssd, "ssd"},
>  	{Opt_ssd_spread, "ssd_spread"},
>  	{Opt_nossd, "nossd"},
> +	{Opt_nossd_spread, "nossd_spread"},
>  	{Opt_acl, "acl"},
>  	{Opt_noacl, "noacl"},
>  	{Opt_notreelog, "notreelog"},
> @@ -582,6 +583,10 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
>  			btrfs_clear_and_info(info, SSD_SPREAD,
>  					     "not using spread ssd allocation scheme");
>  			break;
> +		case Opt_nossd_spread:
> +			btrfs_clear_and_info(info, SSD_SPREAD,
> +					     "not using spread ssd allocation scheme");

The message is the same as above adn the 2 cases can be merged.

> +			break;
>  		case Opt_barrier:
>  			btrfs_clear_and_info(info, NOBARRIER,
>  					     "turning on barriers");
> -- 
> 2.14.1
> 
> --
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