From bbf9f7d90f21e05e31b7cdd95b32f64dd2819dfe Mon Sep 17 00:00:00 2001 From: Sahitya Tummala Date: Wed, 7 Aug 2019 19:10:32 +0530 Subject: [PATCH] f2fs: Fix indefinite loop in f2fs_gc() 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 Reviewed-by: Chao Yu [Jaegeuk Kim: fix wrong bitmap size] Signed-off-by: Jaegeuk Kim --- fs/f2fs/gc.c | 25 ++++++++++++++++++++++++- fs/f2fs/segment.c | 27 +++++++++++++++++++-------- fs/f2fs/segment.h | 3 +++ 3 files changed, 46 insertions(+), 9 deletions(-) diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 8974672db78f..e88f98ddf396 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)) @@ -627,8 +637,21 @@ 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 long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr); + + if (unlikely(check_valid_map(sbi, segno, offset))) { + if (!test_and_set_bit(segno, SIT_I(sbi)->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 426d4a529f5e..cc230fc829e1 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -817,9 +817,13 @@ 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(sbi)->invalid_segmap); +#endif + } } } @@ -3946,7 +3950,7 @@ static int build_sit_info(struct f2fs_sb_info *sbi) struct sit_info *sit_i; unsigned int sit_segs, start; char *src_bitmap, *bitmap; - unsigned int bitmap_size; + unsigned int bitmap_size, main_bitmap_size, sit_bitmap_size; /* allocate memory for SIT information */ sit_i = f2fs_kzalloc(sbi, sizeof(struct sit_info), GFP_KERNEL); @@ -3962,8 +3966,8 @@ static int build_sit_info(struct f2fs_sb_info *sbi) if (!sit_i->sentries) return -ENOMEM; - bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi)); - sit_i->dirty_sentries_bitmap = f2fs_kvzalloc(sbi, bitmap_size, + main_bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi)); + sit_i->dirty_sentries_bitmap = f2fs_kvzalloc(sbi, main_bitmap_size, GFP_KERNEL); if (!sit_i->dirty_sentries_bitmap) return -ENOMEM; @@ -4012,17 +4016,23 @@ static int build_sit_info(struct f2fs_sb_info *sbi) sit_segs = le32_to_cpu(raw_super->segment_count_sit) >> 1; /* setup SIT bitmap from ckeckpoint pack */ - bitmap_size = __bitmap_size(sbi, SIT_BITMAP); + sit_bitmap_size = __bitmap_size(sbi, SIT_BITMAP); src_bitmap = __bitmap_ptr(sbi, SIT_BITMAP); - sit_i->sit_bitmap = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL); + sit_i->sit_bitmap = kmemdup(src_bitmap, sit_bitmap_size, GFP_KERNEL); if (!sit_i->sit_bitmap) return -ENOMEM; #ifdef CONFIG_F2FS_CHECK_FS - sit_i->sit_bitmap_mir = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL); + sit_i->sit_bitmap_mir = kmemdup(src_bitmap, + sit_bitmap_size, GFP_KERNEL); if (!sit_i->sit_bitmap_mir) return -ENOMEM; + + sit_i->invalid_segmap = f2fs_kvzalloc(sbi, + main_bitmap_size, GFP_KERNEL); + if (!sit_i->invalid_segmap) + return -ENOMEM; #endif /* init SIT information */ @@ -4031,7 +4041,7 @@ static int build_sit_info(struct f2fs_sb_info *sbi) sit_i->sit_base_addr = le32_to_cpu(raw_super->sit_blkaddr); sit_i->sit_blocks = sit_segs << sbi->log_blocks_per_seg; sit_i->written_valid_blocks = 0; - sit_i->bitmap_size = bitmap_size; + sit_i->bitmap_size = sit_bitmap_size; sit_i->dirty_sentries = 0; sit_i->sents_per_block = SIT_ENTRY_PER_BLOCK; sit_i->elapsed_time = le64_to_cpu(sbi->ckpt->elapsed_time); @@ -4514,6 +4524,7 @@ 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 ec4d568fd58c..b219009c3e20 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -230,6 +230,9 @@ 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 */