[PATCH v3 2/2] ext2/4, xfs, blk: call dax_get_unmapped_area() for DAX pmd mappings

[Toshi Kani]

To support DAX pmd mappings with unmodified applications,
filesystems need to align an mmap address by the pmd size.

Call dax_get_unmapped_area() from f_op->get_unmapped_area.

Note, there is no change in behavior for a non-DAX file.

Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
---
 fs/block_dev.c    |    1 +
 fs/ext2/file.c    |    1 +
 fs/ext4/file.c    |    1 +
 fs/xfs/xfs_file.c |    1 +
 4 files changed, 4 insertions(+)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 20a2c02..52518e0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1798,6 +1798,7 @@ const struct file_operations def_blk_fops = {
 	.write_iter	= blkdev_write_iter,
 	.mmap		= blkdev_mmap,
 	.fsync		= blkdev_fsync,
+	.get_unmapped_area = dax_get_unmapped_area,
 	.unlocked_ioctl	= block_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= compat_blkdev_ioctl,
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index c1400b1..dbf11eb 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -172,6 +172,7 @@ const struct file_operations ext2_file_operations = {
 	.open		= dquot_file_open,
 	.release	= ext2_release_file,
 	.fsync		= ext2_fsync,
+	.get_unmapped_area = dax_get_unmapped_area,
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 };
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index fa2208b..6c268f8 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -708,6 +708,7 @@ const struct file_operations ext4_file_operations = {
 	.open		= ext4_file_open,
 	.release	= ext4_release_file,
 	.fsync		= ext4_sync_file,
+	.get_unmapped_area = dax_get_unmapped_area,
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= ext4_fallocate,
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 569938a..1e409a6 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1708,6 +1708,7 @@ const struct file_operations xfs_file_operations = {
 	.open		= xfs_file_open,
 	.release	= xfs_file_release,
 	.fsync		= xfs_file_fsync,
+	.get_unmapped_area = dax_get_unmapped_area,
 	.fallocate	= xfs_file_fallocate,
 };