From bbf9f7d90f21e05e31b7cdd95b32f64dd2819dfe Mon Sep 17 00:00:00 2001 From: Sahitya Tummala Date: Wed, 7 Aug 2019 19:10:32 +0530 Subject: 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 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'fs/f2fs/gc.c') 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; } -- cgit v1.2.3