From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751911AbdK1IkL (ORCPT ); Tue, 28 Nov 2017 03:40:11 -0500 Received: from mail-ot0-f196.google.com ([74.125.82.196]:34037 "EHLO mail-ot0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558AbdK1IkK (ORCPT ); Tue, 28 Nov 2017 03:40:10 -0500 X-Google-Smtp-Source: AGs4zMayDxStsCp8RbF+/HyasUppimTbB0CpK1URRm5yMNw/9OVA9qrjYzUZz74IWTbJsvwOdVqb/A== Subject: Re: [Ocfs2-devel] [PATCH 2/3] ocfs2: add ocfs2_overwrite_io function To: Gang He , jlbec@evilplan.org, hch@lst.de, Goldwyn Rodrigues , mfasheh@versity.com Cc: ocfs2-devel@oss.oracle.com, linux-kernel@vger.kernel.org References: <1511775987-841-1-git-send-email-ghe@suse.com> <1511775987-841-3-git-send-email-ghe@suse.com> <123f1322-d453-4aca-ac95-63d6f90fd8a2@gmail.com> <5A1D49E5020000F90009AC66@prv-mh.provo.novell.com> <805fb849-dcc7-cbbc-02af-1c6116a88957@gmail.com> <5A1D7FC2020000F90009AD91@prv-mh.provo.novell.com> From: Joseph Qi Message-ID: <1437e732-35ea-9022-3358-dbe7d2708009@gmail.com> Date: Tue, 28 Nov 2017 16:40:04 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <5A1D7FC2020000F90009AD91@prv-mh.provo.novell.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/11/28 15:24, Gang He wrote: > Hello Joseph, > > >>>> > >> >> On 17/11/28 11:35, Gang He wrote: >>> Hello Joseph, >>> >>> >>>>>> >>>> Hi Gang, >>>> >>>> On 17/11/27 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; >>>>> + 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: >>>> Should brelse(di_bh) be here? >>> If the code jumps to out_unlock1 directly, the di_bh pointer should be NULL, >> it is not necessary to release. >>> >> Umm... No, once going out here, we have already taken inode lock. So >> di_bh should be released. > Sorry, you are right. > >> >>>> >>>>> + ocfs2_inode_unlock(inode, 0); >>>>> + >>>>> +out: >>>>> + return (ret ? 0 : 1); >>>> I don't think EAGAIN and other error code can be handled the same. We >>>> have to distinguish them. >>> Ok, I think we can add one line log to report the error in case the error is >> not EAGAIN. >>> >> My point is, there is no need to try again in several cases, e.g. EROFS >> returned by ocfs2_get_clusters_nocache. > In this function ocfs2_overwrite_io() only can return True(1) or False(0), then I think we can only give a error print before return true/false. > It is not necessary to return another value, but should let the user know any possible error message. >This is because you just ignore the error and convert it to 0 or 1. But in your next patch, if !ocfs2_overwrite_io(), it will return EGAIN to upper layer and let it try again. But in some cases, e.g. EROFS, trying again is meaningless. That's why we can't simply return 0 or 1 here. Also we have to distinguish the error code in the next patch. > Thanks > Gang > >> >>>> >>>> Thanks, >>>> Joseph >>>> >>>>> +} >>>>> + >>>>> 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, >>>>> >>> From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joseph Qi Date: Tue, 28 Nov 2017 16:40:04 +0800 Subject: [Ocfs2-devel] [PATCH 2/3] ocfs2: add ocfs2_overwrite_io function In-Reply-To: <5A1D7FC2020000F90009AD91@prv-mh.provo.novell.com> References: <1511775987-841-1-git-send-email-ghe@suse.com> <1511775987-841-3-git-send-email-ghe@suse.com> <123f1322-d453-4aca-ac95-63d6f90fd8a2@gmail.com> <5A1D49E5020000F90009AC66@prv-mh.provo.novell.com> <805fb849-dcc7-cbbc-02af-1c6116a88957@gmail.com> <5A1D7FC2020000F90009AD91@prv-mh.provo.novell.com> Message-ID: <1437e732-35ea-9022-3358-dbe7d2708009@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Gang He , jlbec@evilplan.org, hch@lst.de, Goldwyn Rodrigues , mfasheh@versity.com Cc: ocfs2-devel@oss.oracle.com, linux-kernel@vger.kernel.org On 17/11/28 15:24, Gang He wrote: > Hello Joseph, > > >>>> > >> >> On 17/11/28 11:35, Gang He wrote: >>> Hello Joseph, >>> >>> >>>>>> >>>> Hi Gang, >>>> >>>> On 17/11/27 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; >>>>> + 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: >>>> Should brelse(di_bh) be here? >>> If the code jumps to out_unlock1 directly, the di_bh pointer should be NULL, >> it is not necessary to release. >>> >> Umm... No, once going out here, we have already taken inode lock. So >> di_bh should be released. > Sorry, you are right. > >> >>>> >>>>> + ocfs2_inode_unlock(inode, 0); >>>>> + >>>>> +out: >>>>> + return (ret ? 0 : 1); >>>> I don't think EAGAIN and other error code can be handled the same. We >>>> have to distinguish them. >>> Ok, I think we can add one line log to report the error in case the error is >> not EAGAIN. >>> >> My point is, there is no need to try again in several cases, e.g. EROFS >> returned by ocfs2_get_clusters_nocache. > In this function ocfs2_overwrite_io() only can return True(1) or False(0), then I think we can only give a error print before return true/false. > It is not necessary to return another value, but should let the user know any possible error message. >This is because you just ignore the error and convert it to 0 or 1. But in your next patch, if !ocfs2_overwrite_io(), it will return EGAIN to upper layer and let it try again. But in some cases, e.g. EROFS, trying again is meaningless. That's why we can't simply return 0 or 1 here. Also we have to distinguish the error code in the next patch. > Thanks > Gang > >> >>>> >>>> Thanks, >>>> Joseph >>>> >>>>> +} >>>>> + >>>>> 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, >>>>> >>>