fs/affs/file.c: add support to O_DIRECT

Based on ext2_direct_IO

Tested with O_DIRECT file open and sysbench/mariadb with 1% written
queries improvement (update_non_index test) on a volume created with
mkaffs.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/fs/affs/file.c b/fs/affs/file.c
index 8e510854f487..05005bd2621a 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -12,6 +12,7 @@
  *  affs regular file handling primitives
  */
 
+#include <linux/aio.h>
 #include "affs.h"
 
 #if PAGE_SIZE < 4096
@@ -392,6 +393,22 @@ static void affs_write_failed(struct address_space *mapping, loff_t to)
         }
 }
 
+static ssize_t
+affs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+               loff_t offset)
+{
+        struct file *file = iocb->ki_filp;
+        struct address_space *mapping = file->f_mapping;
+        struct inode *inode = mapping->host;
+        size_t count = iov_iter_count(iter);
+        ssize_t ret;
+
+        ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, affs_get_block);
+        if (ret < 0 && (rw & WRITE))
+                affs_write_failed(mapping, offset + count);
+        return ret;
+}
+
 static int affs_write_begin(struct file *file, struct address_space *mapping,
                         loff_t pos, unsigned len, unsigned flags,
                         struct page **pagep, void **fsdata)
@@ -418,6 +435,7 @@ const struct address_space_operations affs_aops = {
         .writepage = affs_writepage,
         .write_begin = affs_write_begin,
         .write_end = generic_write_end,
+        .direct_IO = affs_direct_IO,
         .bmap = _affs_bmap
 };