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.

[ghe@suse.com: v3]
Link: http://lkml.kernel.org/r/1514455665-16325-3-git-send-email-ghe@suse.com
[ghe@suse.com: v2]
Link: http://lkml.kernel.org/r/1511944612-9629-3-git-send-email-ghe@suse.com
Link: http://lkml.kernel.org/r/1511775987-841-3-git-send-email-ghe@suse.com
Signed-off-by: Gang He <ghe@suse.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: alex chen <alex.chen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index e4719e0a3f9993b46a0158c78e38c08f3f1158fd..06cb96462bf99a92172da155fe11933f76b22584 100644 (file)
--- 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 @@ out:
        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
index 67ea57d2fd594da7e456c1103bb1652fa68b5f69..1057586ec19f931d6410b74098caf63ccdc694fb 100644 (file)
--- 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,