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, 6 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a75fba67bb1f..982d934fd9ac 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -965,6 +965,11 @@ struct ext4_inode_info {
 #define EXT4_MOUNT_ERRORS_MASK          0x00070
 #define EXT4_MOUNT_MINIX_DF             0x00080 /* Mimics the Minix statfs */
 #define EXT4_MOUNT_NOLOAD               0x00100 /* Don't use existing journal*/
+#ifdef CONFIG_FS_DAX
+#define EXT4_MOUNT_DAX                  0x00200 /* Direct Access */
+#else
+#define EXT4_MOUNT_DAX                  0
+#endif
 #define EXT4_MOUNT_DATA_FLAGS           0x00C00 /* Mode for data writes: */
 #define EXT4_MOUNT_JOURNAL_DATA         0x00400 /* Write data to journal */
 #define EXT4_MOUNT_ORDERED_DATA         0x00800 /* Flush data before commit */
@@ -2578,6 +2583,7 @@ extern const struct file_operations ext4_dir_operations;
 /* file.c */
 extern const struct inode_operations ext4_file_inode_operations;
 extern const struct file_operations ext4_file_operations;
+extern const struct file_operations ext4_dax_file_operations;
 extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
 
 /* inline.c */