[PATCH v4] f2fs: fix a missing discard prefree segments

[PATCH v4] f2fs: fix a missing discard prefree segments

[Yunlei He]

If userspace issue a fstrim with a range not involve prefree segments,
it will reuse these segments without discard. This patch fix it.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
---
 fs/f2fs/segment.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0738f48..30cd445 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -916,9 +916,13 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 		dirty_i->nr_dirty[PRE] -= end - start;
 
-		if (force || !test_opt(sbi, DISCARD))
+		if (!test_opt(sbi, DISCARD))
 			continue;
 
+		if (force && start >= cpc->trim_start &&
+					(end -1) <= cpc->trim_end)
+				continue;
+
 		if (!test_opt(sbi, LFS) || sbi->segs_per_sec == 1) {
 			f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
 				(end - start) << sbi->log_blocks_per_seg);
@@ -2263,8 +2267,11 @@ void flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	f2fs_bug_on(sbi, sit_i->dirty_sentries);
 out:
 	if (cpc->reason == CP_DISCARD) {
+		__u64 trim_start = cpc->trim_start;
 		for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
 			add_discard_addrs(sbi, cpc);
+
+		cpc->trim_start = trim_start;
 	}
 	mutex_unlock(&sit_i->sentry_lock);
 
-- 
2.10.1


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Re: [PATCH v4] f2fs: fix a missing discard prefree segments

[Chao Yu]

On 2016/12/22 11:46, Yunlei He wrote:
> If userspace issue a fstrim with a range not involve prefree segments,
> it will reuse these segments without discard. This patch fix it.
> 
> Signed-off-by: Yunlei He <heyunlei@huawei.com>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

> ---
>  fs/f2fs/segment.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0738f48..30cd445 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -916,9 +916,13 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>  
>  		dirty_i->nr_dirty[PRE] -= end - start;
>  
> -		if (force || !test_opt(sbi, DISCARD))
> +		if (!test_opt(sbi, DISCARD))
>  			continue;
>  
> +		if (force && start >= cpc->trim_start &&
> +					(end -1) <= cpc->trim_end)

Coding style:  (end - 1)

> +				continue;
> +
>  		if (!test_opt(sbi, LFS) || sbi->segs_per_sec == 1) {
>  			f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
>  				(end - start) << sbi->log_blocks_per_seg);
> @@ -2263,8 +2267,11 @@ void flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>  	f2fs_bug_on(sbi, sit_i->dirty_sentries);
>  out:
>  	if (cpc->reason == CP_DISCARD) {
> +		__u64 trim_start = cpc->trim_start;
>  		for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
>  			add_discard_addrs(sbi, cpc);
> +
> +		cpc->trim_start = trim_start;
>  	}
>  	mutex_unlock(&sit_i->sentry_lock);
>  
> 


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Access to Intel Xeon Phi processor-based developer platforms.
With one year of Intel Parallel Studio XE.
Training and support from Colfax.
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