From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: Re: [f2fs-dev] [PATCH] f2fs: add a rw_sem to cover quota flag changes Date: Thu, 30 May 2019 22:01:45 +0800 Message-ID: References: <20190530033115.16853-1-jaegeuk@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190530033115.16853-1-jaegeuk@kernel.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jaegeuk Kim , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net List-Id: linux-f2fs-devel.lists.sourceforge.net On 2019-5-30 11:31, Jaegeuk Kim wrote: > thread 1: thread 2: > writeback checkpoint > set QUOTA_NEED_FLUSH > clear QUOTA_NEED_FLUSH > f2fs_dquot_commit > dquot_commit > clear_dquot_dirty > f2fs_quota_sync > dquot_writeback_dquots > nothing to commit > commit_dqblk > quota_write > f2fs_quota_write > waiting for f2fs_lock_op() > pass __need_flush_quota > (no F2FS_DIRTY_QDATA) At a glance, will it cause deadlock: - f2fs_dquot_commit - down_read(&sbi->quota_sem) - block_operation - f2fs_lock_all - need_flush_quota - down_write(&sbi->quota_sem) - f2fs_quota_write - f2fs_lock_op Thanks, > > -> up-to-date quota is not written > > Signed-off-by: Jaegeuk Kim > --- > fs/f2fs/checkpoint.c | 26 ++++++++++++++++---------- > fs/f2fs/f2fs.h | 1 + > fs/f2fs/super.c | 27 ++++++++++++++++++++++----- > 3 files changed, 39 insertions(+), 15 deletions(-) > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > index 89825261d474..cf3b15c963d2 100644 > --- a/fs/f2fs/checkpoint.c > +++ b/fs/f2fs/checkpoint.c > @@ -1131,17 +1131,23 @@ static void __prepare_cp_block(struct f2fs_sb_info *sbi) > > static bool __need_flush_quota(struct f2fs_sb_info *sbi) > { > + bool ret = false; > + > + down_write(&sbi->quota_sem); > if (!is_journalled_quota(sbi)) > - return false; > - if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) > - return false; > - if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) > - return false; > - if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_FLUSH)) > - return true; > - if (get_pages(sbi, F2FS_DIRTY_QDATA)) > - return true; > - return false; > + ret = false; > + else if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) > + ret = false; > + else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) > + ret = false; > + else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_FLUSH)) > + ret = true; > + else if (get_pages(sbi, F2FS_DIRTY_QDATA)) > + ret = true; > + else > + ret = false; > + up_write(&sbi->quota_sem); > + return ret; > } > > /* > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 9b3d9977cd1e..692c0922f5b2 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1250,6 +1250,7 @@ struct f2fs_sb_info { > block_t unusable_block_count; /* # of blocks saved by last cp */ > > unsigned int nquota_files; /* # of quota sysfile */ > + struct rw_semaphore quota_sem; /* blocking cp for flags */ > > /* # of pages, see count_type */ > atomic_t nr_pages[NR_COUNT_TYPE]; > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 912e2619d581..5ddf5e97ee60 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -1944,7 +1944,10 @@ int f2fs_quota_sync(struct super_block *sb, int type) > int cnt; > int ret; > > + down_read(&sbi->quota_sem); > ret = dquot_writeback_dquots(sb, type); > + up_read(&sbi->quota_sem); > + > if (ret) > goto out; > > @@ -2074,32 +2077,40 @@ static void f2fs_truncate_quota_inode_pages(struct super_block *sb) > > static int f2fs_dquot_commit(struct dquot *dquot) > { > + struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb); > int ret; > > + down_read(&sbi->quota_sem); > ret = dquot_commit(dquot); > if (ret < 0) > - set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR); > + set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR); > + up_read(&sbi->quota_sem); > return ret; > } > > static int f2fs_dquot_acquire(struct dquot *dquot) > { > + struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb); > int ret; > > + down_read(&sbi->quota_sem); > ret = dquot_acquire(dquot); > if (ret < 0) > - set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR); > - > + set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR); > + up_read(&sbi->quota_sem); > return ret; > } > > static int f2fs_dquot_release(struct dquot *dquot) > { > + struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb); > int ret; > > + down_read(&sbi->quota_sem); > ret = dquot_release(dquot); > if (ret < 0) > - set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR); > + set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR); > + up_read(&sbi->quota_sem); > return ret; > } > > @@ -2109,22 +2120,27 @@ static int f2fs_dquot_mark_dquot_dirty(struct dquot *dquot) > struct f2fs_sb_info *sbi = F2FS_SB(sb); > int ret; > > + down_read(&sbi->quota_sem); > ret = dquot_mark_dquot_dirty(dquot); > > /* if we are using journalled quota */ > if (is_journalled_quota(sbi)) > set_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH); > > + up_read(&sbi->quota_sem); > return ret; > } > > static int f2fs_dquot_commit_info(struct super_block *sb, int type) > { > + struct f2fs_sb_info *sbi = F2FS_SB(sb); > int ret; > > + down_read(&sbi->quota_sem); > ret = dquot_commit_info(sb, type); > if (ret < 0) > - set_sbi_flag(F2FS_SB(sb), SBI_QUOTA_NEED_REPAIR); > + set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR); > + up_read(&sbi->quota_sem); > return ret; > } > > @@ -3233,6 +3249,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) > } > > init_rwsem(&sbi->cp_rwsem); > + init_rwsem(&sbi->quota_sem); > init_waitqueue_head(&sbi->cp_wait); > init_sb_info(sbi); > >