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 <g...@suse.com> >> --- >> 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.). 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, >>