fstrim may miss candidates that need to be discarded in fstrim, as shown in
the examples below.
The root cause is that when cpc->reason is set with CP_DISCARD,
add_discard_addrs() expects that ckpt_valid_map and cur_valid_map have been
synced by seg_info_to_raw_sit() [1] and tries to find the candidates based
on ckpt_valid_map and discard_map. However, seg_info_to_raw_sit() does not
actually run before f2fs_exist_trim_candidates(), which results in failure.
root# cp testfile /f2fs_mountpoint
root# f2fs_io fiemap 0 1 /f2fs_mountpoint/testfile
Fiemap: offset = 0 len = 1
logical addr. physical addr. length flags
0 0000000000000000 0000000406a00000 000000003d800000 00001000
root# rm /f2fs_mountpoint/testfile
root# fstrim -v -o 0x406a00000 -l 1024M /f2fs_mountpoint -- no candidate is
found
/f2fs_mountpoint: 0 B (0 bytes) trimmed
[1] Please refer to commit d7bc2484b8d4 ("f2fs: fix small discards not to
issue redundantly") for the relationship between seg_info_to_raw_sit() and
add_discard_addrs().
Fixes: 25290fa5591d ("f2fs: return fs_trim if there is no candidate")
Signed-off-by: Chunhai Guo <guochun...@vivo.com>
---
fs/f2fs/segment.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index eade36c5ef13..8fe9f794b581 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2070,7 +2070,7 @@ static int f2fs_issue_discard(struct f2fs_sb_info *sbi,
}
static bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
- bool check_only)
+ bool synced, bool check_only)
{
int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
struct seg_entry *se = get_seg_entry(sbi, cpc->trim_start);
@@ -2098,7 +2098,7 @@ static bool add_discard_addrs(struct f2fs_sb_info *sbi,
struct cp_control *cpc,
/* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
for (i = 0; i < entries; i++)
- dmap[i] = force ? ~ckpt_map[i] & ~discard_map[i] :
+ dmap[i] = synced ? ~ckpt_map[i] & ~discard_map[i] :
(cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
while (force || SM_I(sbi)->dcc_info->nr_discards <=
@@ -3275,7 +3275,7 @@ bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
down_write(&SIT_I(sbi)->sentry_lock);
for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++) {
- if (add_discard_addrs(sbi, cpc, true)) {
+ if (add_discard_addrs(sbi, cpc, false, true)) {
has_candidate = true;
break;
}
@@ -4611,7 +4611,7 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi,
struct cp_control *cpc)
/* add discard candidates */
if (!(cpc->reason & CP_DISCARD)) {
cpc->trim_start = segno;
- add_discard_addrs(sbi, cpc, false);
+ add_discard_addrs(sbi, cpc, false, false);
}
if (to_journal) {
@@ -4653,7 +4653,7 @@ void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi,
struct cp_control *cpc)
__u64 trim_start = cpc->trim_start;
for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
- add_discard_addrs(sbi, cpc, false);
+ add_discard_addrs(sbi, cpc, true, false);
cpc->trim_start = trim_start;
}
--
2.34.1
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