[PATCH 28/38] vfs: Convert qib_fs/ipathfs to fs_context

[David Howells <dhowells@xxxxxxxxxx>]

[Q] Can qib_remove() race with qibfs_kill_super()?  Should qib_super
    accesses be serialised with some sort of lock?

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
cc: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
cc: linux-rdma@xxxxxxxxxxxxxxx
---

 drivers/infiniband/hw/qib/qib_fs.c |   26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/hw/qib/qib_fs.c b/drivers/infiniband/hw/qib/qib_fs.c
index 1d940a2885c9..fc4f62a248a1 100644
--- a/drivers/infiniband/hw/qib/qib_fs.c
+++ b/drivers/infiniband/hw/qib/qib_fs.c
@@ -34,6 +34,7 @@
 
 #include <linux/module.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/mount.h>
 #include <linux/pagemap.h>
 #include <linux/init.h>
@@ -506,7 +507,7 @@ static int remove_device_files(struct super_block *sb,
  * after device init.  The direct add_cntr_files() call handles adding
  * them from the init code, when the fs is already mounted.
  */
-static int qibfs_fill_super(struct super_block *sb, void *data, int silent)
+static int qibfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct qib_devdata *dd, *tmp;
 	unsigned long flags;
@@ -540,17 +541,26 @@ static int qibfs_fill_super(struct super_block *sb, void *data, int silent)
 	return ret;
 }
 
-static struct dentry *qibfs_mount(struct file_system_type *fs_type, int flags,
-			const char *dev_name, void *data)
+static int qibfs_get_tree(struct fs_context *fc)
 {
-	struct dentry *ret;
+	int ret;
 
-	ret = mount_single(fs_type, flags, data, qibfs_fill_super);
-	if (!IS_ERR(ret))
-		qib_super = ret->d_sb;
+	ret = vfs_get_super(fc, vfs_get_single_super, qibfs_fill_super);
+	if (ret == 0)
+		qib_super = fc->root->d_sb;
 	return ret;
 }
 
+static const struct fs_context_operations qibfs_context_ops = {
+	.get_tree	= qibfs_get_tree,
+};
+
+static int qibfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &qibfs_context_ops;
+	return 0;
+}
+
 static void qibfs_kill_super(struct super_block *s)
 {
 	kill_litter_super(s);
@@ -589,7 +599,7 @@ int qibfs_remove(struct qib_devdata *dd)
 static struct file_system_type qibfs_fs_type = {
 	.owner =        THIS_MODULE,
 	.name =         "ipathfs",
-	.mount =        qibfs_mount,
+	.init_fs_context = qibfs_init_fs_context,
 	.kill_sb =      qibfs_kill_super,
 };
 MODULE_ALIAS_FS("ipathfs");