[PATCH 0/2] ext4: fix two minor mistakes in ext4_es_scan()

[PATCH 0/2] ext4: fix two minor mistakes in ext4_es_scan()

[Zhang Yi]

Fix two minor mistakes introduced by 1ab6c4997e04 ("fs: convert fs
shrinkers to new scan/count API") in  ext4_es_scan().

Zhang Yi (2):
  ext4: remove check for zero nr_to_scan in ext4_es_scan()
  ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit

 fs/ext4/extents_status.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

-- 
2.25.4

[PATCH 1/2] ext4: remove check for zero nr_to_scan in ext4_es_scan()

[Zhang Yi]

After converting fs shrinkers to new scan/count API, we are no longer
pass zero nr_to_scan parameter to detect the number of objects to free,
just remove this check.

Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
Cc: stable@vger.kernel.org # 3.12+
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/ext4/extents_status.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 0a729027322d..db3cd70a72e4 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -1574,9 +1574,6 @@ static unsigned long ext4_es_scan(struct shrinker *shrink,
 	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
 	trace_ext4_es_shrink_scan_enter(sbi->s_sb, nr_to_scan, ret);
 
-	if (!nr_to_scan)
-		return ret;
-
 	nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
 
 	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
-- 
2.25.4

[PATCH 2/2] ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit

[Zhang Yi]

The cache_cnt parameter of tracepoint ext4_es_shrink_exit means the
remaining cache count after shrink, but now it is the cache count before
shrink, fix it by read sbi->s_extent_cache_cnt again.

Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
Cc: stable@vger.kernel.org # 3.12+
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/ext4/extents_status.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index db3cd70a72e4..9a3a8996aacf 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -1576,6 +1576,7 @@ static unsigned long ext4_es_scan(struct shrinker *shrink,
 
 	nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
 
+	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
 	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
 	return nr_shrunk;
 }
-- 
2.25.4

Re: [PATCH 1/2] ext4: remove check for zero nr_to_scan in ext4_es_scan()

[Jan Kara]

On Sat 22-05-21 18:30:44, Zhang Yi wrote:
> After converting fs shrinkers to new scan/count API, we are no longer
> pass zero nr_to_scan parameter to detect the number of objects to free,
> just remove this check.
> 
> Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
> Cc: stable@vger.kernel.org # 3.12+
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Looks good. Thanks for the patch. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/extents_status.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index 0a729027322d..db3cd70a72e4 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -1574,9 +1574,6 @@ static unsigned long ext4_es_scan(struct shrinker *shrink,
>  	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
>  	trace_ext4_es_shrink_scan_enter(sbi->s_sb, nr_to_scan, ret);
>  
> -	if (!nr_to_scan)
> -		return ret;
> -
>  	nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
>  
>  	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
> -- 
> 2.25.4
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 2/2] ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit

[Jan Kara]

On Sat 22-05-21 18:30:45, Zhang Yi wrote:
> The cache_cnt parameter of tracepoint ext4_es_shrink_exit means the
> remaining cache count after shrink, but now it is the cache count before
> shrink, fix it by read sbi->s_extent_cache_cnt again.
> 
> Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
> Cc: stable@vger.kernel.org # 3.12+
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Yeah, probably it is better this way. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/extents_status.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index db3cd70a72e4..9a3a8996aacf 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -1576,6 +1576,7 @@ static unsigned long ext4_es_scan(struct shrinker *shrink,
>  
>  	nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
>  
> +	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
>  	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
>  	return nr_shrunk;
>  }
> -- 
> 2.25.4
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] ext4: remove check for zero nr_to_scan in ext4_es_scan()

[Theodore Ts'o]

On Sat, May 22, 2021 at 06:30:44PM +0800, Zhang Yi wrote:
> After converting fs shrinkers to new scan/count API, we are no longer
> pass zero nr_to_scan parameter to detect the number of objects to free,
> just remove this check.
> 
> Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
> Cc: stable@vger.kernel.org # 3.12+
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Thanks, applied.

					- Ted

Re: [PATCH 2/2] ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit

[Theodore Ts'o]

On Sat, May 22, 2021 at 06:30:45PM +0800, Zhang Yi wrote:
> The cache_cnt parameter of tracepoint ext4_es_shrink_exit means the
> remaining cache count after shrink, but now it is the cache count before
> shrink, fix it by read sbi->s_extent_cache_cnt again.
> 
> Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
> Cc: stable@vger.kernel.org # 3.12+
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Thanks, applied.

				- Ted