Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753876AbdGNL6Q (ORCPT ); Fri, 14 Jul 2017 07:58:16 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:10294 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753519AbdGNL6O (ORCPT ); Fri, 14 Jul 2017 07:58:14 -0400 From: Yunlong Song To: , , , , CC: , , , , Subject: [PATCH] f2fs: let __get_victim successfully get a segno in corner case Date: Fri, 14 Jul 2017 19:57:12 +0800 Message-ID: <1500033432-57620-1-git-send-email-yunlong.song@huawei.com> X-Mailer: git-send-email 1.8.5.2 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.250] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.5968B1AC.0003,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: d7028b0eaa22ab7525764e7ccae6be42 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4207 Lines: 123 Suppose that the valid blocks of each section are all over sbi->fggc_threshold, and even has_not_enough_free_secs is true, f2fs_gc cannot do its job since the no_fggc_candidate always returns true. As a result, the reserved segments can be used up, and finally there is no free segment at all, and get_new_segment cannot get a free segment, filesystem will trap into a wrong status. To fix this, we record the segno which has a rough minimum cost and return it to __get_victim to continue f2fs_gc's job. Signed-off-by: Yunlong Song --- fs/f2fs/gc.c | 19 ++++++++++++++----- fs/f2fs/segment.h | 17 ++++++++++++++--- 2 files changed, 28 insertions(+), 8 deletions(-) diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index fa3d2e2..965e783 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -178,6 +178,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, p->offset = 0; else p->offset = SIT_I(sbi)->last_victim[p->gc_mode]; + + p->min_cost_r = UINT_MAX; } static unsigned int get_max_cost(struct f2fs_sb_info *sbi, @@ -194,7 +196,7 @@ static unsigned int get_max_cost(struct f2fs_sb_info *sbi, return 0; } -static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) +static unsigned int check_bg_victims(struct f2fs_sb_info *sbi, struct victim_sel_policy *p) { struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); unsigned int secno; @@ -208,11 +210,12 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) if (sec_usage_check(sbi, secno)) continue; - if (no_fggc_candidate(sbi, secno)) + p->cur_segno_r = GET_SEG_FROM_SEC(sbi, secno); + if (no_fggc_candidate(sbi, secno, p)) continue; clear_bit(secno, dirty_i->victim_secmap); - return GET_SEG_FROM_SEC(sbi, secno); + return p->cur_segno_r; } return NULL_SEGNO; } @@ -332,7 +335,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, last_victim = sm->last_victim[p.gc_mode]; if (p.alloc_mode == LFS && gc_type == FG_GC) { - p.min_segno = check_bg_victims(sbi); + p.min_segno = check_bg_victims(sbi, &p); if (p.min_segno != NULL_SEGNO) goto got_it; } @@ -369,8 +372,9 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, goto next; if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap)) goto next; + p.cur_segno_r = segno; if (gc_type == FG_GC && p.alloc_mode == LFS && - no_fggc_candidate(sbi, secno)) + no_fggc_candidate(sbi, secno, &p)) goto next; cost = get_gc_cost(sbi, segno, &p); @@ -403,6 +407,11 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, sbi->cur_victim_sec, prefree_segments(sbi), free_segments(sbi)); + } else if (has_not_enough_free_secs(sbi, 0, 0)) { + p.min_segno = p.min_segno_r; + if (p.alloc_mode == LFS && gc_type == FG_GC) + clear_bit(GET_SEC_FROM_SEG(sbi, p.min_segno), dirty_i->victim_secmap); + goto got_it; } out: mutex_unlock(&dirty_i->seglist_lock); diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 6b871b4..7d2d0f3 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -169,6 +169,9 @@ struct victim_sel_policy { unsigned int ofs_unit; /* bitmap search unit */ unsigned int min_cost; /* minimum cost */ unsigned int min_segno; /* segment # having min. cost */ + unsigned int min_cost_r; /* rough minimum cost */ + unsigned int min_segno_r; /* segment # having rough min. cost */ + unsigned int cur_segno_r; /* segment # rough process is handling */ }; struct seg_entry { @@ -743,11 +746,19 @@ static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type) } static inline bool no_fggc_candidate(struct f2fs_sb_info *sbi, - unsigned int secno) + unsigned int secno, struct victim_sel_policy *p) { - if (get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true) >= - sbi->fggc_threshold) + unsigned int cur_cost; + + cur_cost = get_valid_blocks(sbi, GET_SEG_FROM_SEC(sbi, secno), true); + if (cur_cost >= sbi->fggc_threshold) { + if (p->min_cost_r > cur_cost) { + p->min_cost_r = cur_cost; + p->min_segno_r = p->cur_segno_r; + } return true; + } + return false; } -- 1.8.5.2