Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH v4] f2fs: Fix indefinite loop in f2fs_gc() | From | Chao Yu <> | Date | Wed, 7 Aug 2019 22:06:17 +0800 |
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On 2019-8-7 21:40, Sahitya Tummala wrote: > Policy - Foreground GC, LFS and greedy GC mode. > > Under this policy, f2fs_gc() loops forever to GC as it doesn't have > enough free segements to proceed and thus it keeps calling gc_more > for the same victim segment. This can happen if the selected victim > segment could not be GC'd due to failed blkaddr validity check i.e. > is_alive() returns false for the blocks set in current validity map. > > Fix this by keeping track of such invalid segments and skip those > segments for selection in get_victim_by_default() to avoid endless > GC loop under such error scenarios. Currently, add this logic under > CONFIG_F2FS_CHECK_FS to be able to root cause the issue in debug > version. > > Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> > --- > v4: Cover all logic with CONFIG_F2FS_CHECK_FS > > fs/f2fs/gc.c | 31 +++++++++++++++++++++++++++++-- > fs/f2fs/segment.c | 14 +++++++++++++- > fs/f2fs/segment.h | 3 +++ > 3 files changed, 45 insertions(+), 3 deletions(-) > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index 8974672..cbcacbd 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -382,6 +382,16 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, > nsearched++; > } > > +#ifdef CONFIG_F2FS_CHECK_FS > + /* > + * skip selecting the invalid segno (that is failed due to block > + * validity check failure during GC) to avoid endless GC loop in > + * such cases. > + */ > + if (test_bit(segno, sm->invalid_segmap)) > + goto next; > +#endif > + > secno = GET_SEC_FROM_SEG(sbi, segno); > > if (sec_usage_check(sbi, secno)) > @@ -602,8 +612,15 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, > { > struct page *node_page; > nid_t nid; > - unsigned int ofs_in_node; > + unsigned int ofs_in_node, segno; > block_t source_blkaddr; > + unsigned long offset; > +#ifdef CONFIG_F2FS_CHECK_FS > + struct sit_info *sit_i = SIT_I(sbi); > +#endif > + > + segno = GET_SEGNO(sbi, blkaddr); > + offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr); > > nid = le32_to_cpu(sum->nid); > ofs_in_node = le16_to_cpu(sum->ofs_in_node); > @@ -627,8 +644,18 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, > source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node); > f2fs_put_page(node_page, 1); > > - if (source_blkaddr != blkaddr) > + if (source_blkaddr != blkaddr) { > +#ifdef CONFIG_F2FS_CHECK_FS
unsigned int segno = GET_SEGNO(sbi, blkaddr); unsigned int offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
Should be local, otherwise it looks good to me, I think Jaegeuk can help to fix this while merging.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Thanks,
> + if (unlikely(check_valid_map(sbi, segno, offset))) { > + if (!test_and_set_bit(segno, sit_i->invalid_segmap)) { > + f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u\n", > + blkaddr, source_blkaddr, segno); > + f2fs_bug_on(sbi, 1); > + } > + } > +#endif > return false; > + } > return true; > } > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index a661ac3..ee795b1 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -806,6 +806,9 @@ static void __remove_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno, > enum dirty_type dirty_type) > { > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > +#ifdef CONFIG_F2FS_CHECK_FS > + struct sit_info *sit_i = SIT_I(sbi); > +#endif > > if (test_and_clear_bit(segno, dirty_i->dirty_segmap[dirty_type])) > dirty_i->nr_dirty[dirty_type]--; > @@ -817,9 +820,13 @@ static void __remove_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno, > if (test_and_clear_bit(segno, dirty_i->dirty_segmap[t])) > dirty_i->nr_dirty[t]--; > > - if (get_valid_blocks(sbi, segno, true) == 0) > + if (get_valid_blocks(sbi, segno, true) == 0) { > clear_bit(GET_SEC_FROM_SEG(sbi, segno), > dirty_i->victim_secmap); > +#ifdef CONFIG_F2FS_CHECK_FS > + clear_bit(segno, sit_i->invalid_segmap); > +#endif > + } > } > } > > @@ -4015,6 +4022,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi) > sit_i->sit_bitmap_mir = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL); > if (!sit_i->sit_bitmap_mir) > return -ENOMEM; > + > + sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL); > + if (!sit_i->invalid_segmap) > + return -ENOMEM; > #endif > > /* init SIT information */ > @@ -4517,6 +4528,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi) > kvfree(sit_i->sit_bitmap); > #ifdef CONFIG_F2FS_CHECK_FS > kvfree(sit_i->sit_bitmap_mir); > + kvfree(sit_i->invalid_segmap); > #endif > kvfree(sit_i); > } > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index b746028..9370d53 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -229,6 +229,9 @@ struct sit_info { > char *sit_bitmap; /* SIT bitmap pointer */ > #ifdef CONFIG_F2FS_CHECK_FS > char *sit_bitmap_mir; /* SIT bitmap mirror */ > + > + /* bitmap of segments to be ignored by GC in case of errors */ > + unsigned long *invalid_segmap; > #endif > unsigned int bitmap_size; /* SIT bitmap size */ > >
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