ocfs2: add ocfs2_overwrite_io()

Add ocfs2_overwrite_io function, which is used to judge if overwrite allocated blocks, otherwise, the write will bring extra block allocation overhead. [[email protected]: v3] Link: http://lkml.kernel.org/r/[email protected] [[email protected]: v2] Link: http://lkml.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Gang He <[email protected]> Reviewed-by: Changwei Ge <[email protected]> Cc: Mark Fasheh <[email protected]> Cc: Joel Becker <[email protected]> Cc: Junxiao Bi <[email protected]> Cc: Joseph Qi <[email protected]> Cc: Jun Piao <[email protected]> Cc: alex chen <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
imcsk8 · Feb 1, 2018 · ac604d3 · ac604d3
1 parent 06e7f13
commit ac604d3
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diff --git 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)
+{
+	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
@@ -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,