Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livep...

[mirror_ubuntu-artful-kernel.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index d9f5336552d7b12cad62315a2c512a9ca922bf55..ad7242043bdb8b74872e536b61d01ca05a1de6b3 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1695,8 +1695,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
        loff_t *ppos = &iocb->ki_pos;
        loff_t pos = *ppos;
 
-       /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
-       if (file->f_flags & O_DIRECT) {
+       if (io_is_direct(file)) {
                struct address_space *mapping = file->f_mapping;
                struct inode *inode = mapping->host;
                size_t count = iov_iter_count(iter);
@@ -1723,9 +1722,11 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
                 * we've already read everything we wanted to, or if
                 * there was a short read because we hit EOF, go ahead
                 * and return.  Otherwise fallthrough to buffered io for
-                * the rest of the read.
+                * the rest of the read.  Buffered reads will not work for
+                * DAX files, so don't bother trying.
                 */
-               if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) {
+               if (retval < 0 || !iov_iter_count(iter) || *ppos >= size ||
+                   IS_DAX(inode)) {
                        file_accessed(file);
                        goto out;
                }
@@ -2582,18 +2583,20 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
        if (err)
                goto out;
 
-       /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
-       if (unlikely(file->f_flags & O_DIRECT)) {
+       if (io_is_direct(file)) {
                loff_t endbyte;
 
                written = generic_file_direct_write(iocb, from, pos);
-               if (written < 0 || written == count)
-                       goto out;
-
                /*
-                * direct-io write to a hole: fall through to buffered I/O
-                * for completing the rest of the request.
+                * If the write stopped short of completing, fall back to
+                * buffered writes.  Some filesystems do this for writes to
+                * holes, for example.  For DAX files, a buffered write will
+                * not succeed (even if it did, DAX does not handle dirty
+                * page-cache pages correctly).
                 */
+               if (written < 0 || written == count || IS_DAX(inode))
+                       goto out;
+
                pos += written;
                count -= written;