Gang He
2017-Nov-28 07:24 UTC
[Ocfs2-devel] [PATCH 2/3] ocfs2: add ocfs2_overwrite_io function
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 <ghe at suse.com> >>>> --- >>>> 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. 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, >>>> >>
Joseph Qi
2017-Nov-28 08:40 UTC
[Ocfs2-devel] [PATCH 2/3] ocfs2: add ocfs2_overwrite_io function
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 <ghe at suse.com> >>>>> --- >>>>> 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, >>>>> >>>