On 2018/7/17 17:05, Chao Yu wrote:
On 2018/7/16 18:03, Yunlong Song wrote:
For the case when sbi->segs_per_sec > 1 with lfs mode, take
section:segment = 5 for example, if the section prefree_map is
...previous section | current section (1 1 0 1 1) | next section...,
then the start = x, end = x + 1, after start = start_segno +
sbi->segs_per_sec, start = x + 5, then it will skip x + 3 and x + 4, but
their bitmap is still set, which will cause duplicated
f2fs_issue_discard of this same section in the next write_checkpoint, so
fix it.
I mean:
Subject: [PATCH] f2fs: issue discard align to section in LFS mode
---
fs/f2fs/segment.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index f12dad627fb4..6640c790cf64 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1761,6 +1761,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
unsigned int start = 0, end = -1;
unsigned int secno, start_segno;
bool force = (cpc->reason & CP_DISCARD);
+ bool need_align = test_opt(sbi, LFS) && sbi->segs_per_sec > 1;
mutex_lock(&dirty_i->seglist_lock);
@@ -1772,10 +1773,15 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info
*sbi,
end = find_next_zero_bit(prefree_map, MAIN_SEGS(sbi),
start + 1);
- for (i = start; i < end; i++)
- clear_bit(i, prefree_map);
+ if (need_align) {
+ start = rounddown(start, sbi->segs_per_sec);
+ end = roundup(start, sbi->segs_per_sec);
+ }
- dirty_i->nr_dirty[PRE] -= end - start;
+ for (i = start; i < end; i++) {
+ if (test_and_clear_bit(i, prefree_map))
+ dirty_i->nr_dirty[PRE]--;
+ }
The above part should be put below if (!test_opt(sbi, DISCARD)), or in
test_opt(sbi, DISCARD) == 0 case,
the first segment of the next section will be skipped, if only the first
segment is prefree and all the other
segments of the section are not prefree.
if (!test_opt(sbi, DISCARD))
continue;
@@ -2564,6 +2570,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct
fstrim_range *range)
struct discard_policy dpolicy;
unsigned long long trimmed = 0;
int err = 0;
+ bool need_align = test_opt(sbi, LFS) && sbi->segs_per_sec > 1;
if (start >= MAX_BLKADDR(sbi) || range->len < sbi->blocksize)
return -EINVAL;
@@ -2582,6 +2589,12 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct
fstrim_range *range)
end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
GET_SEGNO(sbi, end);
+ if (need_align) {
+ start_segno = rounddown(start_segno, sbi->segs_per_sec);
+ end_segno = roundup(end_segno, sbi->segs_per_sec);
+ end_segno = min(end_segno, MAIN_SEGS(sbi) - 1);
+ }
+
cpc.reason = CP_DISCARD;
cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
cpc.trim_start = start_segno;
--
Thanks,
Yunlong Song
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