From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753838AbdKGCRn (ORCPT ); Mon, 6 Nov 2017 21:17:43 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:10016 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752575AbdKGCRm (ORCPT ); Mon, 6 Nov 2017 21:17:42 -0500 Subject: Re: [PATCH v3] f2fs: fix out-of-free problem caused by atomic write To: Jaegeuk Kim , Yunlong Song CC: , , , , , , References: <1509934071-116656-1-git-send-email-yunlong.song@huawei.com> <20171107015543.GB88544@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: Date: Tue, 7 Nov 2017 10:17:12 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20171107015543.GB88544@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.5A0117AF.00EE,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: 2d2258825146a4f67a00ad47654a03e2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/11/7 9:55, Jaegeuk Kim wrote: > On 11/06, Yunlong Song wrote: >> f2fs_balance_fs only actives once in the commit_inmem_pages, but there >> are more than one page to commit, so all the other pages will miss the >> check. This will lead to out-of-free problem when commit a very large >> file. However, we cannot do f2fs_balance_fs for each inmem page, since >> this will break atomicity. As a result, we should collect prefree >> segments if needed. >> >> Signed-off-by: Yunlong Song >> --- >> fs/f2fs/f2fs.h | 1 + >> fs/f2fs/segment.c | 24 +++++++++++++++++++++++- >> 2 files changed, 24 insertions(+), 1 deletion(-) >> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index 13a96b8..04ce48f 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -610,6 +610,7 @@ struct f2fs_inode_info { >> struct list_head inmem_pages; /* inmemory pages managed by f2fs */ >> struct task_struct *inmem_task; /* store inmemory task */ >> struct mutex inmem_lock; /* lock for inmemory pages */ >> + unsigned long inmem_blocks; /* inmemory blocks */ >> struct extent_tree *extent_tree; /* cached extent_tree entry */ >> struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */ >> struct rw_semaphore i_mmap_sem; >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index 46dfbca..b87ede4 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -210,6 +210,7 @@ void register_inmem_page(struct inode *inode, struct page *page) >> list_add_tail(&fi->inmem_ilist, &sbi->inode_list[ATOMIC_FILE]); >> spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); >> inc_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES); >> + fi->inmem_blocks++; >> mutex_unlock(&fi->inmem_lock); >> >> trace_f2fs_register_inmem_page(page, INMEM); >> @@ -221,6 +222,7 @@ static int __revoke_inmem_pages(struct inode *inode, >> struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> struct inmem_pages *cur, *tmp; >> int err = 0; >> + struct f2fs_inode_info *fi = F2FS_I(inode); >> >> list_for_each_entry_safe(cur, tmp, head, list) { >> struct page *page = cur->page; >> @@ -263,6 +265,7 @@ static int __revoke_inmem_pages(struct inode *inode, >> list_del(&cur->list); >> kmem_cache_free(inmem_entry_slab, cur); >> dec_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES); >> + fi->inmem_blocks--; >> } >> return err; >> } >> @@ -302,6 +305,10 @@ void drop_inmem_pages(struct inode *inode) >> if (!list_empty(&fi->inmem_ilist)) >> list_del_init(&fi->inmem_ilist); >> spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); >> + if (fi->inmem_blocks) { >> + f2fs_bug_on(sbi, 1); >> + fi->inmem_blocks = 0; >> + } >> mutex_unlock(&fi->inmem_lock); >> >> clear_inode_flag(inode, FI_ATOMIC_FILE); >> @@ -326,6 +333,7 @@ void drop_inmem_page(struct inode *inode, struct page *page) >> >> f2fs_bug_on(sbi, !cur || cur->page != page); >> list_del(&cur->list); >> + fi->inmem_blocks--; >> mutex_unlock(&fi->inmem_lock); >> >> dec_page_count(sbi, F2FS_INMEM_PAGES); >> @@ -410,6 +418,16 @@ int commit_inmem_pages(struct inode *inode) >> >> INIT_LIST_HEAD(&revoke_list); >> f2fs_balance_fs(sbi, true); >> + if (prefree_segments(sbi) >> + && has_not_enough_free_secs(sbi, 0, >> + fi->inmem_blocks / BLKS_PER_SEC(sbi))) { >> + struct cp_control cpc; >> + >> + cpc.reason = __get_cp_reason(sbi); >> + err = write_checkpoint(sbi, &cpc); >> + if (err) >> + goto drop; > > What do you want to guarantee with this? How about passing target # of segments > into f2fs_balance_fs() so that f2fs_gc() could secure wanted free space in a > loop? Agreed, Jaegeuk, IMO, later we can add one more dirty type F2FS_DIRTY_BUDGET in enum count_type, and introduce below function, add them around dirtying node/dent/imeta datas. void f2fs_budget_space(struct f2fs_sb_info *sbi, unsigned int dirty_budget) { if (dirty_budget) atomic_add(&sbi->nr_pages[F2FS_DIRTY_BUDGET], dirty_budget); f2fs_balance_fs(sbi, dirty_budget); } void f2fs_release_budget(struct f2fs_sb_info *sbi, unsigned int dirty_budget) { atomic_dec(&sbi->nr_pages[F2FS_DIRTY_BUDGET], dirty_budget); } So that in has_not_enough_free_secs we can calculate all dirty datas include F2FS_DIRTY_BUDGET type datas more precisely. How about that? Thanks, > > Thanks, > >> + } >> f2fs_lock_op(sbi); >> >> set_inode_flag(inode, FI_ATOMIC_COMMIT); >> @@ -429,7 +447,7 @@ int commit_inmem_pages(struct inode *inode) >> ret = __revoke_inmem_pages(inode, &revoke_list, false, true); >> if (ret) >> err = ret; >> - >> +drop: >> /* drop all uncommitted pages */ >> __revoke_inmem_pages(inode, &fi->inmem_pages, true, false); >> } >> @@ -437,6 +455,10 @@ int commit_inmem_pages(struct inode *inode) >> if (!list_empty(&fi->inmem_ilist)) >> list_del_init(&fi->inmem_ilist); >> spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); >> + if (fi->inmem_blocks) { >> + f2fs_bug_on(sbi, 1); >> + fi->inmem_blocks = 0; >> + } >> mutex_unlock(&fi->inmem_lock); >> >> clear_inode_flag(inode, FI_ATOMIC_COMMIT); >> -- >> 1.8.5.2 > > . >