new helpers: vfs_create_mount(), fc_mount()
Create a new helper, vfs_create_mount(), that creates a detached vfsmount
object from an fs_context that has a superblock attached to it.
Almost all uses will be paired with immediately preceding vfs_get_tree();
add a helper for such combination.
Switch vfs_kern_mount() to use this.
NOTE: mild behaviour change; passing NULL as 'device name' to
something like procfs will change /proc/*/mountstats - "device none"
instead on "no device". That is consistent with /proc/mounts et.al.
[do'h - EXPORT_SYMBOL_GPL slipped in by mistake; removed]
[AV -- remove confused comment from vfs_create_mount()]
[AV -- removed the second argument]
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 3f2fd7a..156771f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -941,12 +941,59 @@ static struct mount *skip_mnt_tree(struct mount *p)
return p;
}
+/**
+ * vfs_create_mount - Create a mount for a configured superblock
+ * @fc: The configuration context with the superblock attached
+ *
+ * Create a mount to an already configured superblock. If necessary, the
+ * caller should invoke vfs_get_tree() before calling this.
+ *
+ * Note that this does not attach the mount to anything.
+ */
+struct vfsmount *vfs_create_mount(struct fs_context *fc)
+{
+ struct mount *mnt;
+
+ if (!fc->root)
+ return ERR_PTR(-EINVAL);
+
+ mnt = alloc_vfsmnt(fc->source ?: "none");
+ if (!mnt)
+ return ERR_PTR(-ENOMEM);
+
+ if (fc->sb_flags & SB_KERNMOUNT)
+ mnt->mnt.mnt_flags = MNT_INTERNAL;
+
+ atomic_inc(&fc->root->d_sb->s_active);
+ mnt->mnt.mnt_sb = fc->root->d_sb;
+ mnt->mnt.mnt_root = dget(fc->root);
+ mnt->mnt_mountpoint = mnt->mnt.mnt_root;
+ mnt->mnt_parent = mnt;
+
+ lock_mount_hash();
+ list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
+ unlock_mount_hash();
+ return &mnt->mnt;
+}
+EXPORT_SYMBOL(vfs_create_mount);
+
+struct vfsmount *fc_mount(struct fs_context *fc)
+{
+ int err = vfs_get_tree(fc);
+ if (!err) {
+ up_write(&fc->root->d_sb->s_umount);
+ return vfs_create_mount(fc);
+ }
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL(fc_mount);
+
struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int flags, const char *name,
void *data)
{
struct fs_context *fc;
- struct mount *mnt;
+ struct vfsmount *mnt;
int ret = 0;
if (!type)
@@ -964,31 +1011,12 @@ struct vfsmount *vfs_kern_mount(struct file_system_type *type,
if (!ret)
ret = parse_monolithic_mount_data(fc, data);
if (!ret)
- ret = vfs_get_tree(fc);
- if (ret) {
- put_fs_context(fc);
- return ERR_PTR(ret);
- }
- up_write(&fc->root->d_sb->s_umount);
- mnt = alloc_vfsmnt(name);
- if (!mnt) {
- put_fs_context(fc);
- return ERR_PTR(-ENOMEM);
- }
+ mnt = fc_mount(fc);
+ else
+ mnt = ERR_PTR(ret);
- if (flags & SB_KERNMOUNT)
- mnt->mnt.mnt_flags = MNT_INTERNAL;
-
- atomic_inc(&fc->root->d_sb->s_active);
- mnt->mnt.mnt_root = dget(fc->root);
- mnt->mnt.mnt_sb = fc->root->d_sb;
- mnt->mnt_mountpoint = mnt->mnt.mnt_root;
- mnt->mnt_parent = mnt;
- lock_mount_hash();
- list_add_tail(&mnt->mnt_instance, &fc->root->d_sb->s_mounts);
- unlock_mount_hash();
put_fs_context(fc);
- return &mnt->mnt;
+ return mnt;
}
EXPORT_SYMBOL_GPL(vfs_kern_mount);
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 037eed5..9197ddb 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -21,6 +21,7 @@ struct super_block;
struct vfsmount;
struct dentry;
struct mnt_namespace;
+struct fs_context;
#define MNT_NOSUID 0x01
#define MNT_NODEV 0x02
@@ -88,6 +89,8 @@ struct path;
extern struct vfsmount *clone_private_mount(const struct path *path);
struct file_system_type;
+extern struct vfsmount *fc_mount(struct fs_context *fc);
+extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int flags, const char *name,
void *data);
