From 4b93dc9b1c684d0587fe44d36bbfdf45bd3bea9d Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 28 Nov 2013 14:54:43 -0500 Subject: sysfs, kernfs: prepare mount path for kernfs We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch rearranges mount path so that the kernfs and sysfs parts are separate. * As sysfs_super_info won't be visible outside kernfs proper, kernfs_super_ns() is added to allow kernfs users to access a super_block's namespace tag. * Generic mount operation is separated out into kernfs_mount_ns(). sysfs_mount() now just performs sysfs-specific permission check, acquires namespace tag, and invokes kernfs_mount_ns(). * Generic superblock release is separated out into kernfs_kill_sb() which can be used directly as file_system_type->kill_sb(). As sysfs needs to put the namespace tag, sysfs_kill_sb() wraps kernfs_kill_sb() with ns tag put. * sysfs_dir_cachep init and sysfs_inode_init() are separated out into kernfs_init(). kernfs_init() uses only small amount of memory and trying to handle and propagate kernfs_init() failure doesn't make much sense. Use SLAB_PANIC for sysfs_dir_cachep and make sysfs_inode_init() panic on failure. After this change, kernfs_init() should be called before sysfs_init(), fs/namespace.c::mnt_init() modified accordingly. Signed-off-by: Tejun Heo Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig Signed-off-by: Greg Kroah-Hartman --- include/linux/kernfs.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include') diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index fad8b986800f..75fcbe5c9d65 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -18,6 +18,8 @@ struct file; struct iattr; struct seq_file; struct vm_area_struct; +struct super_block; +struct file_system_type; struct sysfs_dirent; @@ -109,6 +111,13 @@ void kernfs_enable_ns(struct sysfs_dirent *sd); int kernfs_setattr(struct sysfs_dirent *sd, const struct iattr *iattr); void kernfs_notify(struct sysfs_dirent *sd); +const void *kernfs_super_ns(struct super_block *sb); +struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, + struct kernfs_root *root, const void *ns); +void kernfs_kill_sb(struct super_block *sb); + +void kernfs_init(void); + #else /* CONFIG_SYSFS */ static inline struct sysfs_dirent * @@ -160,6 +169,18 @@ static inline int kernfs_setattr(struct sysfs_dirent *sd, static inline void kernfs_notify(struct sysfs_dirent *sd) { } +static inline const void *kernfs_super_ns(struct super_block *sb) +{ return NULL; } + +static inline struct dentry * +kernfs_mount_ns(struct file_system_type *fs_type, int flags, + struct kernfs_root *root, const void *ns) +{ return ERR_PTR(-ENOSYS); } + +static inline void kernfs_kill_sb(struct super_block *sb) { } + +static inline void kernfs_init(void) { } + #endif /* CONFIG_SYSFS */ static inline struct sysfs_dirent * @@ -201,4 +222,11 @@ static inline int kernfs_remove_by_name(struct sysfs_dirent *parent, return kernfs_remove_by_name_ns(parent, name, NULL); } +static inline struct dentry * +kernfs_mount(struct file_system_type *fs_type, int flags, + struct kernfs_root *root) +{ + return kernfs_mount_ns(fs_type, flags, root, NULL); +} + #endif /* __LINUX_KERNFS_H */ -- cgit v1.2.3