dax,ext2: replace XIP read and write with DAX I/O

Use the generic AIO infrastructure instead of custom read and write
methods.  In addition to giving us support for AIO, this adds the missing
locking between read() and truncate().

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 0cb04486577d..3ccd5fd47d66 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -859,7 +859,12 @@ ext2_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
         size_t count = iov_iter_count(iter);
         ssize_t ret;
 
-        ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, ext2_get_block);
+        if (IS_DAX(inode))
+                ret = dax_do_io(rw, iocb, inode, iter, offset, ext2_get_block,
+                                NULL, DIO_LOCKING);
+        else
+                ret = blockdev_direct_IO(rw, iocb, inode, iter, offset,
+                                         ext2_get_block);
         if (ret < 0 && (rw & WRITE))
                 ext2_write_failed(mapping, offset + count);
         return ret;
@@ -888,6 +893,7 @@ const struct address_space_operations ext2_aops = {
 const struct address_space_operations ext2_aops_xip = {
         .bmap                   = ext2_bmap,
         .get_xip_mem            = ext2_get_xip_mem,
+        .direct_IO              = ext2_direct_IO,
 };
 
 const struct address_space_operations ext2_nobh_aops = {