dax: unify ext2/4_{dax,}_file_operations

The original dax patchset split the ext2/4_file_operations because of the
two NULL splice_read/splice_write in the dax case.

In the vfs if splice_read/splice_write are NULL we then call
default_splice_read/write.

What we do here is make generic_file_splice_read aware of IS_DAX() so the
original ext2/4_file_operations can be used as is.

For write it appears that iter_file_splice_write is just fine.  It uses
the regular f_op->write(file,..) or new_sync_write(file, ...).

Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 41cbb16299e0..476024bb6546 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -523,6 +523,9 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
         loff_t isize, left;
         int ret;
 
+        if (IS_DAX(in->f_mapping->host))
+                return default_file_splice_read(in, ppos, pipe, len, flags);
+
         isize = i_size_read(in->f_mapping->host);
         if (unlikely(*ppos >= isize))
                 return 0;