[PATCH 09/18] btrfs: Add dax specific address_space_operations

[Goldwyn Rodrigues]

From: Goldwyn Rodrigues <rgold...@suse.com>

Signed-off-by: Goldwyn Rodrigues <rgold...@suse.com>
---
 fs/btrfs/inode.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index af4b56cba104..05714ffc4894 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -28,6 +28,7 @@
 #include <linux/magic.h>
 #include <linux/iversion.h>
 #include <linux/swap.h>
+#include <linux/dax.h>
 #include <asm/unaligned.h>
 #include "ctree.h"
 #include "disk-io.h"
@@ -65,6 +66,7 @@ static const struct inode_operations 
btrfs_dir_ro_inode_operations;
 static const struct inode_operations btrfs_special_inode_operations;
 static const struct inode_operations btrfs_file_inode_operations;
 static const struct address_space_operations btrfs_aops;
+static const struct address_space_operations btrfs_dax_aops;
 static const struct file_operations btrfs_dir_file_operations;
 static const struct extent_io_ops btrfs_extent_io_ops;
 
@@ -3757,7 +3759,10 @@ static int btrfs_read_locked_inode(struct inode *inode,
 
        switch (inode->i_mode & S_IFMT) {
        case S_IFREG:
-               inode->i_mapping->a_ops = &btrfs_aops;
+               if (btrfs_test_opt(fs_info, DAX))
+                       inode->i_mapping->a_ops = &btrfs_dax_aops;
+               else
+                       inode->i_mapping->a_ops = &btrfs_aops;
                BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
                inode->i_fop = &btrfs_file_operations;
                inode->i_op = &btrfs_file_inode_operations;
@@ -3778,6 +3783,7 @@ static int btrfs_read_locked_inode(struct inode *inode,
        }
 
        btrfs_sync_inode_flags_to_i_flags(inode);
+
        return 0;
 }
 
@@ -6538,7 +6544,10 @@ static int btrfs_create(struct inode *dir, struct dentry 
*dentry,
        */
        inode->i_fop = &btrfs_file_operations;
        inode->i_op = &btrfs_file_inode_operations;
-       inode->i_mapping->a_ops = &btrfs_aops;
+       if (IS_DAX(inode) && S_ISREG(mode))
+               inode->i_mapping->a_ops = &btrfs_dax_aops;
+       else
+               inode->i_mapping->a_ops = &btrfs_aops;
 
        err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
        if (err)
@@ -8665,6 +8674,15 @@ static int btrfs_writepages(struct address_space 
*mapping,
        return extent_writepages(mapping, wbc);
 }
 
+static int btrfs_dax_writepages(struct address_space *mapping,
+                           struct writeback_control *wbc)
+{
+       struct inode *inode = mapping->host;
+       struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+       return dax_writeback_mapping_range(mapping, 
fs_info->fs_devices->latest_bdev,
+                       wbc);
+}
+
 static int
 btrfs_readpages(struct file *file, struct address_space *mapping,
                struct list_head *pages, unsigned nr_pages)
@@ -10436,7 +10454,10 @@ static int btrfs_tmpfile(struct inode *dir, struct 
dentry *dentry, umode_t mode)
        inode->i_fop = &btrfs_file_operations;
        inode->i_op = &btrfs_file_inode_operations;
 
-       inode->i_mapping->a_ops = &btrfs_aops;
+       if (IS_DAX(inode))
+               inode->i_mapping->a_ops = &btrfs_dax_aops;
+       else
+               inode->i_mapping->a_ops = &btrfs_aops;
        BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 
        ret = btrfs_init_inode_security(trans, inode, dir, NULL);
@@ -10892,6 +10913,13 @@ static const struct address_space_operations 
btrfs_aops = {
        .swap_deactivate = btrfs_swap_deactivate,
 };
 
+static const struct address_space_operations btrfs_dax_aops = {
+       .writepages             = btrfs_dax_writepages,
+       .direct_IO              = noop_direct_IO,
+       .set_page_dirty         = noop_set_page_dirty,
+       .invalidatepage         = noop_invalidatepage,
+};
+
 static const struct inode_operations btrfs_file_inode_operations = {
        .getattr        = btrfs_getattr,
        .setattr        = btrfs_setattr,
-- 
2.16.4

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