Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753660AbeAKCAE (ORCPT + 1 other); Wed, 10 Jan 2018 21:00:04 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:3769 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753112AbeAKCAA (ORCPT ); Wed, 10 Jan 2018 21:00:00 -0500 Message-ID: <5A56C50E.5070800@huawei.com> Date: Thu, 11 Jan 2018 09:59:42 +0800 From: alex chen User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Gang He CC: , , , Subject: Re: [Ocfs2-devel] [PATCH v3 2/3] ocfs2: add ocfs2_overwrite_io function References: <1514455665-16325-1-git-send-email-ghe@suse.com> <1514455665-16325-3-git-send-email-ghe@suse.com> <5A4B666B.1040803@huawei.com> <5A4CD719020000F9000A0FE0@prv-mh.provo.novell.com> <5A4D7EF2.4030605@huawei.com> <5A4E10B8020000F9000A122B@prv-mh.provo.novell.com> In-Reply-To: <5A4E10B8020000F9000A122B@prv-mh.provo.novell.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.26.59] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi Gang, On 2018/1/4 11:32, Gang He wrote: > Hi Alex, > > >>>> >> Hi Gang, >> >> On 2018/1/3 13:14, Gang He wrote: >>> Hi Alex, >>> >>> >>>>>> >>>> Hi Gang, >>>> >>>> On 2017/12/28 18:07, 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 | 45 +++++++++++++++++++++++++++++++++++++++++++++ >>>>> fs/ocfs2/extent_map.h | 3 +++ >>>>> 2 files changed, 48 insertions(+) >>>>> >>>>> diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c >>>>> index e4719e0..06cb964 100644 >>>>> --- a/fs/ocfs2/extent_map.c >>>>> +++ b/fs/ocfs2/extent_map.c >>>>> @@ -38,6 +38,7 @@ >>>>> #include "inode.h" >>>>> #include "super.h" >>>>> #include "symlink.h" >>>>> +#include "aops.h" >>>>> #include "ocfs2_trace.h" >>>>> >>>>> #include "buffer_head_io.h" >>>>> @@ -832,6 +833,50 @@ 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, struct buffer_head *di_bh, >>>>> + u64 map_start, u64 map_len) >>>> Here can the type of 'map_start' is struct loff_t and map_len is struct >>>> size_t? >>> I prefer to use the detailed types for file start address and length in >> ocfs2_overwrite_io() function declaration, >>> then here will be a potential type conversion (loff_t -> u64, size_t -> u64), I >> think this conversion should be considered as expectation. >>> Since our OCFS2 is a 64 bit file system, the related data types do not >> change, but loff_t and size_t type can change under different architectures >> (e.g. x86_32, x86_64, etc.). >>> >> The type conversion (loff_t -> u64, size_t -> u64) has been made before calling >> the function ocfs2_overwrite_io(). >> So it doesn't matter which type we use for file start address and length in >> ocfs2_overwrite_io(), Right? >> To be consistent with the context, is it better to use struct loff_t for >> 'map_start' and struct size_t for 'map_len'? > I am not sure if I describe my thought clearly. > In VFS layer, loff_t, size_t and other related data types are used for all architectures, that means these kinds of data type's lengths > will change based on different CPU bits. > But, for a specific file system, the file system bit is fixed, e.g. ocfs2 is a 64 bits file system, this bit length is determined by file system layout (not CPU bits). > Then, in this layer we should use fixed-length (or common) data type in the code, the VFS layer data types should be converted into our data types potentially (but except pointer type). > I agree about you to use fixed-length data type in OCFS2 layer, but now we already use the loff_t for pos in ocfs2_prepare_inode_for_write(), I don't think it's going to work whatever data type we use. Right ? Anyway, I accept it if you think it is better to use fixed-length type here. Reviewed-by: Alex Chen Thanks, Alex > > Thanks > Gang > >> >> Thanks, >> Alex >> >>> Thanks >>> Gang >>> >>>> >>>> Thanks, >>>> Alex >>>>> +{ >>>>> + int ret = 0, is_last; >>>>> + u32 mapping_end, cpos; >>>>> + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); >>>>> + struct ocfs2_extent_rec rec; >>>>> + >>>>> + if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) { >>>>> + if (ocfs2_size_fits_inline_data(di_bh, map_start + map_len)) >>>>> + return ret; >>>>> + else >>>>> + return -EAGAIN; >>>>> + } >>>>> + >>>>> + 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; >>>>> + } >>>>> + >>>>> + 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 = -EAGAIN; >>>>> +out: >>>>> + return ret; >>>>> +} >>>>> + >>>>> 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..1057586 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, struct buffer_head *di_bh, >>>>> + u64 map_start, u64 map_len); >>>>> + >>>>> 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, >>>>> >>> >>> >>> . >>> > > . >