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Diffstat (limited to 'fs/kernfs/mount.c')
-rw-r--r--fs/kernfs/mount.c47
1 files changed, 45 insertions, 2 deletions
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 0d6ce895a9ee..6a5f04ac8704 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -19,12 +19,49 @@
struct kmem_cache *kernfs_node_cache;
-static const struct super_operations kernfs_sops = {
+static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+ struct kernfs_root *root = kernfs_info(sb)->root;
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->remount_fs)
+ return scops->remount_fs(root, flags, data);
+ return 0;
+}
+
+static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
+{
+ struct kernfs_root *root = kernfs_root(dentry->d_fsdata);
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->show_options)
+ return scops->show_options(sf, root);
+ return 0;
+}
+
+const struct super_operations kernfs_sops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
.evict_inode = kernfs_evict_inode,
+
+ .remount_fs = kernfs_sop_remount_fs,
+ .show_options = kernfs_sop_show_options,
};
+/**
+ * kernfs_root_from_sb - determine kernfs_root associated with a super_block
+ * @sb: the super_block in question
+ *
+ * Return the kernfs_root associated with @sb. If @sb is not a kernfs one,
+ * %NULL is returned.
+ */
+struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
+{
+ if (sb->s_op == &kernfs_sops)
+ return kernfs_info(sb)->root;
+ return NULL;
+}
+
static int kernfs_fill_super(struct super_block *sb)
{
struct kernfs_super_info *info = kernfs_info(sb);
@@ -94,6 +131,7 @@ const void *kernfs_super_ns(struct super_block *sb)
* @fs_type: file_system_type of the fs being mounted
* @flags: mount flags specified for the mount
* @root: kernfs_root of the hierarchy being mounted
+ * @new_sb_created: tell the caller if we allocated a new superblock
* @ns: optional namespace tag of the mount
*
* This is to be called from each kernfs user's file_system_type->mount()
@@ -104,7 +142,8 @@ const void *kernfs_super_ns(struct super_block *sb)
* The return value can be passed to the vfs layer verbatim.
*/
struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
- struct kernfs_root *root, const void *ns)
+ struct kernfs_root *root, bool *new_sb_created,
+ const void *ns)
{
struct super_block *sb;
struct kernfs_super_info *info;
@@ -122,6 +161,10 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
kfree(info);
if (IS_ERR(sb))
return ERR_CAST(sb);
+
+ if (new_sb_created)
+ *new_sb_created = !sb->s_root;
+
if (!sb->s_root) {
error = kernfs_fill_super(sb);
if (error) {