[PATCH 19/52] virito-fs: Make dax optional

[Vivek Goyal <vgoyal@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Add a 'dax' option and only enable dax when it's on.

Also show "dax" in mount options if filesystem was mounted with dax
enabled.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 fs/fuse/fuse_i.h    | 1 +
 fs/fuse/inode.c     | 8 ++++++++
 fs/fuse/virtio_fs.c | 2 +-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index b5a6a12e67d6..345abe9b022f 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -70,6 +70,7 @@ struct fuse_mount_data {
 	unsigned group_id_present:1;
 	unsigned default_permissions:1;
 	unsigned allow_other:1;
+	unsigned dax:1;
 	unsigned max_read;
 	unsigned blksize;
 };
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 10e4a39318c4..d2afce377fd4 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -439,6 +439,7 @@ enum {
 	OPT_ALLOW_OTHER,
 	OPT_MAX_READ,
 	OPT_BLKSIZE,
+	OPT_DAX,
 	OPT_ERR
 };
 
@@ -452,6 +453,7 @@ static const match_table_t tokens = {
 	{OPT_ALLOW_OTHER,		"allow_other"},
 	{OPT_MAX_READ,			"max_read=%u"},
 	{OPT_BLKSIZE,			"blksize=%u"},
+	{OPT_DAX,			"dax"},
 	{OPT_ERR,			NULL}
 };
 
@@ -543,6 +545,10 @@ int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
 			d->blksize = value;
 			break;
 
+		case OPT_DAX:
+			d->dax = 1;
+			break;
+
 		default:
 			return 0;
 		}
@@ -571,6 +577,8 @@ static int fuse_show_options(struct seq_file *m, struct dentry *root)
 		seq_printf(m, ",max_read=%u", fc->max_read);
 	if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 		seq_printf(m, ",blksize=%lu", sb->s_blocksize);
+	if (fc->dax_dev)
+		seq_printf(m, ",dax");
 	return 0;
 }
 
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 55bac1465536..e4d5e0cd41ba 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -1050,7 +1050,7 @@ static int virtio_fs_fill_super(struct super_block *sb, void *data,
 	/* TODO this sends FUSE_INIT and could cause hiprio or notifications
 	 * virtqueue races since they haven't been set up yet!
 	 */
-	err = fuse_fill_super_common(sb, &d, fs->dax_dev,
+	err = fuse_fill_super_common(sb, &d, d.dax ? fs->dax_dev : NULL,
 				     &virtio_fs_fiq_ops, fs,
 				     (void **)&fs->vqs[2].fud);
 	if (err < 0)
-- 
2.13.6