udf: add writepages support for udf

Use mpage_writepages() instead of multiple calls to udf_writepage()
to make performance higher.

*Write Speed with writepage() =
 RecSize     ReadSpeed    WriteSpeed  RanReadSpeed RanWriteSpeed
10485760    0.00MB/sec    8.56MB/sec    0.00MB/sec    8.20MB/sec
 1048576    0.00MB/sec    8.57MB/sec    0.00MB/sec    6.42MB/sec
  524288    0.00MB/sec    8.59MB/sec    0.00MB/sec    5.24MB/sec
  262144    0.00MB/sec    8.59MB/sec    0.00MB/sec    4.17MB/sec
  131072    0.00MB/sec    8.53MB/sec    0.00MB/sec    3.32MB/sec
   65536    0.00MB/sec    8.49MB/sec    0.00MB/sec    2.31MB/sec

*Write Speed with writepages()
RecSize     ReadSpeed    WriteSpeed  RanReadSpeed RanWriteSpeed
10485760    0.00MB/sec    9.88MB/sec    0.00MB/sec    9.60MB/sec
 1048576    0.00MB/sec    9.95MB/sec    0.00MB/sec    7.52MB/sec
  524288    0.00MB/sec    9.98MB/sec    0.00MB/sec    6.16MB/sec
  262144    0.00MB/sec    9.90MB/sec    0.00MB/sec    4.98MB/sec
  131072    0.00MB/sec    9.89MB/sec    0.00MB/sec    3.78MB/sec
   65536    0.00MB/sec    9.81MB/sec    0.00MB/sec    2.50MB/sec

There is about 1.4MB/sec speed improvement over 8.5MB/sec,
which comes out around 16% improvement.

Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Ashish Sangwan <ashish.sangwan2@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index aa23346..1a0588e 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -100,6 +100,12 @@ static int udf_writepage(struct page *page, struct writeback_control *wbc)
        return block_write_full_page(page, udf_get_block, wbc);
 }
 
+static int udf_writepages(struct address_space *mapping,
+                       struct writeback_control *wbc)
+{
+       return mpage_writepages(mapping, wbc, udf_get_block);
+}
+
 static int udf_readpage(struct file *file, struct page *page)
 {
        return mpage_readpage(page, udf_get_block);
@@ -145,6 +151,7 @@ const struct address_space_operations udf_aops = {
        .readpage       = udf_readpage,
        .readpages      = udf_readpages,
        .writepage      = udf_writepage,
+       .writepages     = udf_writepages,
        .write_begin            = udf_write_begin,
        .write_end              = generic_write_end,
        .bmap           = udf_bmap,