ext4: add DAX functionality

This is a port of the DAX functionality found in the current version of
ext2.

[matthew.r.wilcox@intel.com: heavily tweaked]
[akpm@linux-foundation.org: remap_pages went away]
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
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, 8 insertions, 2 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 2291923dae4e..28fe71a2904c 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2235,7 +2235,10 @@ retry:
         err = PTR_ERR(inode);
         if (!IS_ERR(inode)) {
                 inode->i_op = &ext4_file_inode_operations;
-                inode->i_fop = &ext4_file_operations;
+                if (test_opt(inode->i_sb, DAX))
+                        inode->i_fop = &ext4_dax_file_operations;
+                else
+                        inode->i_fop = &ext4_file_operations;
                 ext4_set_aops(inode);
                 err = ext4_add_nondir(handle, dentry, inode);
                 if (!err && IS_DIRSYNC(dir))
@@ -2299,7 +2302,10 @@ retry:
         err = PTR_ERR(inode);
         if (!IS_ERR(inode)) {
                 inode->i_op = &ext4_file_inode_operations;
-                inode->i_fop = &ext4_file_operations;
+                if (test_opt(inode->i_sb, DAX))
+                        inode->i_fop = &ext4_dax_file_operations;
+                else
+                        inode->i_fop = &ext4_file_operations;
                 ext4_set_aops(inode);
                 d_tmpfile(dentry, inode);
                 err = ext4_orphan_add(handle, inode);