From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751451AbdK1F1m convert rfc822-to-8bit (ORCPT ); Tue, 28 Nov 2017 00:27:42 -0500 Received: from prv-mh.provo.novell.com ([137.65.248.74]:53899 "EHLO prv-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750904AbdK1F1l (ORCPT ); Tue, 28 Nov 2017 00:27:41 -0500 Message-Id: <5A1D6444020000F90009ACCB@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.2.2 Date: Mon, 27 Nov 2017 22:27:32 -0700 From: "Gang He" To: , , , , "Goldwyn Rodrigues" , Cc: , Subject: Re: [Ocfs2-devel] [PATCH 2/3] ocfs2: add ocfs2_overwrite_io function References: <1511775987-841-1-git-send-email-ghe@suse.com> <1511775987-841-3-git-send-email-ghe@suse.com> <5A1CC0EA.9010100@huawei.com> <63ADC13FD55D6546B7DECE290D39E373F1470AB8@H3CMLB12-EX.srv.huawei-3com.com> In-Reply-To: <63ADC13FD55D6546B7DECE290D39E373F1470AB8@H3CMLB12-EX.srv.huawei-3com.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> > On 2017/11/28 9:52, piaojun wrote: >> Hi Gang, >> >> If ocfs2_overwrite_io is only called in 'nowait' scenarios, I wonder if >> we can discard 'int wait' just as ext4 does: >> >> static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len); > > Yes, Jun has a point. > It seems that ocfs2_overwrite_io is only involved in non-blocking aio > and no other code spot is calling ocfs2_overwrite_io with wait=1 passed. Ok, I will do this change. > >> >> thans, >> Jun >> >> On 2017/11/27 17:46, Gang He wrote: >>> Add ocfs2_overwrite_io function, which is used to judge if >>> overwrite allocated blocks, otherwise, the write will bring extra >>> block allocation overhead. >>> >>> Signed-off-by: Gang He >>> --- >>> fs/ocfs2/extent_map.c | 67 > +++++++++++++++++++++++++++++++++++++++++++++++++++ >>> fs/ocfs2/extent_map.h | 3 +++ >>> 2 files changed, 70 insertions(+) >>> >>> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c >>> index e4719e0..98bf325 100644 >>> --- a/fs/ocfs2/extent_map.c >>> +++ b/fs/ocfs2/extent_map.c >>> @@ -832,6 +832,73 @@ int ocfs2_fiemap(struct inode *inode, struct > fiemap_extent_info *fieinfo, >>> return ret; >>> } >>> >>> +/* Is IO overwriting allocated blocks? */ >>> +int ocfs2_overwrite_io(struct inode *inode, u64 map_start, u64 map_len, >>> + int wait) >>> +{ >>> + int ret = 0, is_last; >>> + u32 mapping_end, cpos; >>> + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); >>> + struct buffer_head *di_bh = NULL; >>> + struct ocfs2_extent_rec rec; >>> + >>> + if (wait) >>> + ret = ocfs2_inode_lock(inode, &di_bh, 0); >>> + else >>> + ret = ocfs2_try_inode_lock(inode, &di_bh, 0); >>> + if (ret) >>> + goto out; >>> + >>> + if (wait) >>> + down_read(&OCFS2_I(inode)->ip_alloc_sem); >>> + else { >>> + if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) { >>> + ret = -EAGAIN; > Here is a little strange, it seems that you don't care much about how > this function fails. Why evaluate _ret_ to -EAGAIN here and ignore it > later? > > Thanks, > Changwei > >>> + goto out_unlock1; >>> + } >>> + } >>> + >>> + if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) && >>> + ((map_start + map_len) <= i_size_read(inode))) >>> + goto out_unlock2; >>> + >>> + cpos = map_start >> osb->s_clustersize_bits; >>> + mapping_end = ocfs2_clusters_for_bytes(inode->i_sb, >>> + map_start + map_len); >>> + is_last = 0; >>> + while (cpos < mapping_end && !is_last) { >>> + ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, >>> + NULL, &rec, &is_last); >>> + if (ret) { >>> + mlog_errno(ret); >>> + goto out_unlock2; >>> + } >>> + >>> + if (rec.e_blkno == 0ULL) >>> + break; >>> + >>> + if (rec.e_flags & OCFS2_EXT_REFCOUNTED) >>> + break; >>> + >>> + cpos = le32_to_cpu(rec.e_cpos) + >>> + le16_to_cpu(rec.e_leaf_clusters); >>> + } >>> + >>> + if (cpos < mapping_end) >>> + ret = 1; >>> + >>> +out_unlock2: >>> + brelse(di_bh); >>> + >>> + up_read(&OCFS2_I(inode)->ip_alloc_sem); >>> + >>> +out_unlock1: >>> + ocfs2_inode_unlock(inode, 0); >>> + >>> +out: >>> + return (ret ? 0 : 1); >>> +} >>> + >>> int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int > whence) >>> { >>> struct inode *inode = file->f_mapping->host; >>> diff --git a/fs/ocfs2/extent_map.h b/fs/ocfs2/extent_map.h >>> index 67ea57d..fd9e86a 100644 >>> --- a/fs/ocfs2/extent_map.h >>> +++ b/fs/ocfs2/extent_map.h >>> @@ -53,6 +53,9 @@ int ocfs2_extent_map_get_blocks(struct inode *inode, u64 > v_blkno, u64 *p_blkno, >>> int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, >>> u64 map_start, u64 map_len); >>> >>> +int ocfs2_overwrite_io(struct inode *inode, u64 map_start, u64 map_len, >>> + int wait); >>> + >>> int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int > origin); >>> >>> int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster, >>> >> >> _______________________________________________ >> Ocfs2-devel mailing list >> Ocfs2-devel@oss.oracle.com >> https://oss.oracle.com/mailman/listinfo/ocfs2-devel >>