In SSR mode, the segment selected for allocation might be the same as
the target segment of the GC triggered by ioctl, resulting in the GC
moving the CURSEG_I(sbi, type)->segno.
Thread A Thread B or Thread A
- f2fs_ioc_gc_range
- __f2fs_ioc_gc_range(.victim_segno=segno#N)
- f2fs_gc
- __get_victim
- f2fs_get_victim
: segno#N is valid, return segno#N as source segment of GC
- f2fs_allocate_data_block
- need_new_seg
- get_ssr_segment
- f2fs_get_victim
: get segno #N as destination
segment
- change_curseg
Fixes: e066b83c9b40 ("f2fs: add ioctl to flush data from faster device to cold
area")
Signed-off-by: Yongpeng Yang <yangyongpe...@oppo.com>
---
V2: Include an explanation of concurrent scenarios.
---
fs/f2fs/gc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 3e1b6d2ff3a7..8029369bb71d 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -806,11 +806,14 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned
int *result,
goto out;
}
- if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
+ if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result))) {
ret = -EBUSY;
- else
- p.min_segno = *result;
- goto out;
+ goto out;
+ }
+ if (gc_type == FG_GC)
+ clear_bit(GET_SEC_FROM_SEG(sbi, *result),
dirty_i->victim_secmap);
+ p.min_segno = *result;
+ goto got_result;
}
ret = -ENODATA;
--
2.34.1
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