| Message ID | 1507728318-113117-1-git-send-email-yunlong.song@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Yunlong, On 2017/10/11 21:25, Yunlong Song wrote: > Without this patch, it will cause all the free segments using up in some > corner case. For example, there are 100 segments, and 20 of them are > reserved for ovp. If 79 segments are full of data, segment 80 becomes > CURSEG segment, write 512 blocks and then delete 511 blocks. Since it is > CURSEG segment, the __locate_dirty_segment will not update its dirty > status. Then the dirty_segments(sbi) is 0, f2fs_gc will fail to > get_victim, and f2fs_balance_fs will fail to trigger gc action. After > f2fs_balance_fs returns, f2fs can continue to write data to segment 81. > Again, segment 81 becomes CURSEG segment, write 512 blocks and delete > 511 blocks, the dirty_segments(sbi) is 0 and f2fs_gc fail again. This > can finally use up all the free segments and cause panic. Should we also remove the check in locate_dirty_segment? Thanks, > > Signed-off-by: Yunlong Song <yunlong.song@huawei.com> > --- > fs/f2fs/segment.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index bfbcff8..0ff52d5 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -686,10 +686,6 @@ static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno, > { > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > > - /* need not be added */ > - if (IS_CURSEG(sbi, segno)) > - return; > - > if (!test_and_set_bit(segno, dirty_i->dirty_segmap[dirty_type])) > dirty_i->nr_dirty[dirty_type]++; > >
Correct, I will update the patch. On 2017/10/13 19:08, Chao Yu wrote: > Hi Yunlong, > > On 2017/10/11 21:25, Yunlong Song wrote: >> Without this patch, it will cause all the free segments using up in some >> corner case. For example, there are 100 segments, and 20 of them are >> reserved for ovp. If 79 segments are full of data, segment 80 becomes >> CURSEG segment, write 512 blocks and then delete 511 blocks. Since it is >> CURSEG segment, the __locate_dirty_segment will not update its dirty >> status. Then the dirty_segments(sbi) is 0, f2fs_gc will fail to >> get_victim, and f2fs_balance_fs will fail to trigger gc action. After >> f2fs_balance_fs returns, f2fs can continue to write data to segment 81. >> Again, segment 81 becomes CURSEG segment, write 512 blocks and delete >> 511 blocks, the dirty_segments(sbi) is 0 and f2fs_gc fail again. This >> can finally use up all the free segments and cause panic. > Should we also remove the check in locate_dirty_segment? > > Thanks, > >> Signed-off-by: Yunlong Song <yunlong.song@huawei.com> >> --- >> fs/f2fs/segment.c | 4 ---- >> 1 file changed, 4 deletions(-) >> >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index bfbcff8..0ff52d5 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -686,10 +686,6 @@ static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno, >> { >> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); >> >> - /* need not be added */ >> - if (IS_CURSEG(sbi, segno)) >> - return; >> - >> if (!test_and_set_bit(segno, dirty_i->dirty_segmap[dirty_type])) >> dirty_i->nr_dirty[dirty_type]++; >> >> > . >
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index bfbcff8..0ff52d5 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -686,10 +686,6 @@ static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno, { struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); - /* need not be added */ - if (IS_CURSEG(sbi, segno)) - return; - if (!test_and_set_bit(segno, dirty_i->dirty_segmap[dirty_type])) dirty_i->nr_dirty[dirty_type]++;
Without this patch, it will cause all the free segments using up in some corner case. For example, there are 100 segments, and 20 of them are reserved for ovp. If 79 segments are full of data, segment 80 becomes CURSEG segment, write 512 blocks and then delete 511 blocks. Since it is CURSEG segment, the __locate_dirty_segment will not update its dirty status. Then the dirty_segments(sbi) is 0, f2fs_gc will fail to get_victim, and f2fs_balance_fs will fail to trigger gc action. After f2fs_balance_fs returns, f2fs can continue to write data to segment 81. Again, segment 81 becomes CURSEG segment, write 512 blocks and delete 511 blocks, the dirty_segments(sbi) is 0 and f2fs_gc fail again. This can finally use up all the free segments and cause panic. Signed-off-by: Yunlong Song <yunlong.song@huawei.com> --- fs/f2fs/segment.c | 4 ---- 1 file changed, 4 deletions(-)