vfs: bury ->get_sb() (1a102ff9) · Commits · EulixOS / Software / Kernel

Documentation/filesystems/Locking

+2 −4

Original line number	Original line	Diff line number	Diff line
	@@ -166,13 +166,11 @@ prototypes:
	void (kill_sb) (struct super_block );		void (kill_sb) (struct super_block );
	locking rules:		locking rules:
	may block		may block
	get_sb yes
	mount yes		mount yes
	kill_sb yes		kill_sb yes

	->get_sb() returns error or 0 with locked superblock attached to the vfsmount		->mount() returns ERR_PTR or the root dentry; its superblock should be locked
	(exclusive on ->s_umount).		on return.
	->mount() returns ERR_PTR or the root dentry.
	->kill_sb() takes a write-locked superblock, does all shutdown work on it,		->kill_sb() takes a write-locked superblock, does all shutdown work on it,
	unlocks and drops the reference.		unlocks and drops the reference.

Documentation/filesystems/porting

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -394,3 +394,10 @@ file) you must return -EOPNOTSUPP if FALLOC_FL_PUNCH_HOLE is set in mode.
	Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set,		Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set,
	so the i_size should not change when hole punching, even when puching the end of		so the i_size should not change when hole punching, even when puching the end of
	a file off.		a file off.

			--
			[mandatory]
			->get_sb() is gone. Switch to use of ->mount(). Typically it's just
			a matter of switching from calling get_sb_... to mount_... and changing the
			function type. If you were doing it manually, just switch from setting ->mnt_root
			to some pointer to returning that pointer. On errors return ERR_PTR(...).

Documentation/filesystems/vfs.txt

+32 −24

Original line number	Original line	Diff line number	Diff line
	@@ -95,10 +95,11 @@ functions:
	extern int unregister_filesystem(struct file_system_type *);		extern int unregister_filesystem(struct file_system_type *);

	The passed struct file_system_type describes your filesystem. When a		The passed struct file_system_type describes your filesystem. When a
	request is made to mount a device onto a directory in your filespace,		request is made to mount a filesystem onto a directory in your namespace,
	the VFS will call the appropriate get_sb() method for the specific		the VFS will call the appropriate mount() method for the specific
	filesystem. The dentry for the mount point will then be updated to		filesystem. New vfsmount refering to the tree returned by ->mount()
	point to the root inode for the new filesystem.		will be attached to the mountpoint, so that when pathname resolution
			reaches the mountpoint it will jump into the root of that vfsmount.

	You can see all filesystems that are registered to the kernel in the		You can see all filesystems that are registered to the kernel in the
	file /proc/filesystems.		file /proc/filesystems.
	@@ -107,14 +108,14 @@ file /proc/filesystems.
	struct file_system_type		struct file_system_type
	-----------------------		-----------------------

	This describes the filesystem. As of kernel 2.6.22, the following		This describes the filesystem. As of kernel 2.6.39, the following
	members are defined:		members are defined:

	struct file_system_type {		struct file_system_type {
	const char *name;		const char *name;
	int fs_flags;		int fs_flags;
	int (get_sb) (struct file_system_type , int,		struct dentry (mount) (struct file_system_type , int,
	const char , void , struct vfsmount *);		const char , void );
	void (kill_sb) (struct super_block );		void (kill_sb) (struct super_block );
	struct module *owner;		struct module *owner;
	struct file_system_type * next;		struct file_system_type * next;
	@@ -128,11 +129,11 @@ struct file_system_type {

	fs_flags: various flags (i.e. FS_REQUIRES_DEV, FS_NO_DCACHE, etc.)		fs_flags: various flags (i.e. FS_REQUIRES_DEV, FS_NO_DCACHE, etc.)

	get_sb: the method to call when a new instance of this		mount: the method to call when a new instance of this
	filesystem should be mounted		filesystem should be mounted

	kill_sb: the method to call when an instance of this filesystem		kill_sb: the method to call when an instance of this filesystem
	should be unmounted		should be shut down

	owner: for internal VFS use: you should initialize this to THIS_MODULE in		owner: for internal VFS use: you should initialize this to THIS_MODULE in
	most cases.		most cases.
	@@ -141,7 +142,7 @@ struct file_system_type {

	s_lock_key, s_umount_key: lockdep-specific		s_lock_key, s_umount_key: lockdep-specific

	The get_sb() method has the following arguments:		The mount() method has the following arguments:

	struct file_system_type *fs_type: describes the filesystem, partly initialized		struct file_system_type *fs_type: describes the filesystem, partly initialized
	by the specific filesystem code		by the specific filesystem code
	@@ -153,32 +154,39 @@ The get_sb() method has the following arguments:
	void *data: arbitrary mount options, usually comes as an ASCII		void *data: arbitrary mount options, usually comes as an ASCII
	string (see "Mount Options" section)		string (see "Mount Options" section)

	struct vfsmount *mnt: a vfs-internal representation of a mount point		The mount() method must return the root dentry of the tree requested by
			caller. An active reference to its superblock must be grabbed and the
			superblock must be locked. On failure it should return ERR_PTR(error).

	The get_sb() method must determine if the block device specified		The arguments match those of mount(2) and their interpretation
	in the dev_name and fs_type contains a filesystem of the type the method		depends on filesystem type. E.g. for block filesystems, dev_name is
	supports. If it succeeds in opening the named block device, it initializes a		interpreted as block device name, that device is opened and if it
	struct super_block descriptor for the filesystem contained by the block device.		contains a suitable filesystem image the method creates and initializes
	On failure it returns an error.		struct super_block accordingly, returning its root dentry to caller.

			->mount() may choose to return a subtree of existing filesystem - it
			doesn't have to create a new one. The main result from the caller's
			point of view is a reference to dentry at the root of (sub)tree to
			be attached; creation of new superblock is a common side effect.

	The most interesting member of the superblock structure that the		The most interesting member of the superblock structure that the
	get_sb() method fills in is the "s_op" field. This is a pointer to		mount() method fills in is the "s_op" field. This is a pointer to
	a "struct super_operations" which describes the next level of the		a "struct super_operations" which describes the next level of the
	filesystem implementation.		filesystem implementation.

	Usually, a filesystem uses one of the generic get_sb() implementations		Usually, a filesystem uses one of the generic mount() implementations
	and provides a fill_super() method instead. The generic methods are:		and provides a fill_super() callback instead. The generic variants are:

	get_sb_bdev: mount a filesystem residing on a block device		mount_bdev: mount a filesystem residing on a block device

	get_sb_nodev: mount a filesystem that is not backed by a device		mount_nodev: mount a filesystem that is not backed by a device

	get_sb_single: mount a filesystem which shares the instance between		mount_single: mount a filesystem which shares the instance between
	all mounts		all mounts

	A fill_super() method implementation has the following arguments:		A fill_super() callback implementation has the following arguments:

	struct super_block *sb: the superblock structure. The method fill_super()		struct super_block *sb: the superblock structure. The callback
	must initialize this properly.		must initialize this properly.

	void *data: arbitrary mount options, usually comes as an ASCII		void *data: arbitrary mount options, usually comes as an ASCII

fs/super.c

+6 −61

Original line number	Original line	Diff line number	Diff line
	@@ -843,23 +843,6 @@ struct dentry mount_bdev(struct file_system_type fs_type,
	}		}
	EXPORT_SYMBOL(mount_bdev);		EXPORT_SYMBOL(mount_bdev);

	int get_sb_bdev(struct file_system_type *fs_type,
	int flags, const char dev_name, void data,
	int (fill_super)(struct super_block , void *, int),
	struct vfsmount *mnt)
	{
	struct dentry *root;

	root = mount_bdev(fs_type, flags, dev_name, data, fill_super);
	if (IS_ERR(root))
	return PTR_ERR(root);
	mnt->mnt_root = root;
	mnt->mnt_sb = root->d_sb;
	return 0;
	}

	EXPORT_SYMBOL(get_sb_bdev);

	void kill_block_super(struct super_block *sb)		void kill_block_super(struct super_block *sb)
	{		{
	struct block_device *bdev = sb->s_bdev;		struct block_device *bdev = sb->s_bdev;
	@@ -897,22 +880,6 @@ struct dentry mount_nodev(struct file_system_type fs_type,
	}		}
	EXPORT_SYMBOL(mount_nodev);		EXPORT_SYMBOL(mount_nodev);

	int get_sb_nodev(struct file_system_type *fs_type,
	int flags, void *data,
	int (fill_super)(struct super_block , void *, int),
	struct vfsmount *mnt)
	{
	struct dentry *root;

	root = mount_nodev(fs_type, flags, data, fill_super);
	if (IS_ERR(root))
	return PTR_ERR(root);
	mnt->mnt_root = root;
	mnt->mnt_sb = root->d_sb;
	return 0;
	}
	EXPORT_SYMBOL(get_sb_nodev);

	static int compare_single(struct super_block s, void p)		static int compare_single(struct super_block s, void p)
	{		{
	return 1;		return 1;
	@@ -943,22 +910,6 @@ struct dentry mount_single(struct file_system_type fs_type,
	}		}
	EXPORT_SYMBOL(mount_single);		EXPORT_SYMBOL(mount_single);

	int get_sb_single(struct file_system_type *fs_type,
	int flags, void *data,
	int (fill_super)(struct super_block , void *, int),
	struct vfsmount *mnt)
	{
	struct dentry *root;
	root = mount_single(fs_type, flags, data, fill_super);
	if (IS_ERR(root))
	return PTR_ERR(root);
	mnt->mnt_root = root;
	mnt->mnt_sb = root->d_sb;
	return 0;
	}

	EXPORT_SYMBOL(get_sb_single);

	struct vfsmount *		struct vfsmount *
	vfs_kern_mount(struct file_system_type type, int flags, const char name, void *data)		vfs_kern_mount(struct file_system_type type, int flags, const char name, void *data)
	{		{
	@@ -988,7 +939,6 @@ vfs_kern_mount(struct file_system_type type, int flags, const char name, void
	goto out_free_secdata;		goto out_free_secdata;
	}		}

	if (type->mount) {
	root = type->mount(type, flags, name, data);		root = type->mount(type, flags, name, data);
	if (IS_ERR(root)) {		if (IS_ERR(root)) {
	error = PTR_ERR(root);		error = PTR_ERR(root);
	@@ -996,11 +946,6 @@ vfs_kern_mount(struct file_system_type type, int flags, const char name, void
	}		}
	mnt->mnt_root = root;		mnt->mnt_root = root;
	mnt->mnt_sb = root->d_sb;		mnt->mnt_sb = root->d_sb;
	} else {
	error = type->get_sb(type, flags, name, data, mnt);
	if (error < 0)
	goto out_free_secdata;
	}
	BUG_ON(!mnt->mnt_sb);		BUG_ON(!mnt->mnt_sb);
	WARN_ON(!mnt->mnt_sb->s_bdi);		WARN_ON(!mnt->mnt_sb->s_bdi);
	mnt->mnt_sb->s_flags \|= MS_BORN;		mnt->mnt_sb->s_flags \|= MS_BORN;

include/linux/fs.h

+0 −14

Original line number	Original line	Diff line number	Diff line
	@@ -1797,8 +1797,6 @@ int sync_inode_metadata(struct inode *inode, int wait);
	struct file_system_type {		struct file_system_type {
	const char *name;		const char *name;
	int fs_flags;		int fs_flags;
	int (get_sb) (struct file_system_type , int,
	const char , void , struct vfsmount *);
	struct dentry (mount) (struct file_system_type *, int,		struct dentry (mount) (struct file_system_type *, int,
	const char , void );		const char , void );
	void (kill_sb) (struct super_block );		void (kill_sb) (struct super_block );
	@@ -1821,24 +1819,12 @@ extern struct dentry mount_ns(struct file_system_type fs_type, int flags,
	extern struct dentry mount_bdev(struct file_system_type fs_type,		extern struct dentry mount_bdev(struct file_system_type fs_type,
	int flags, const char dev_name, void data,		int flags, const char dev_name, void data,
	int (fill_super)(struct super_block , void *, int));		int (fill_super)(struct super_block , void *, int));
	extern int get_sb_bdev(struct file_system_type *fs_type,
	int flags, const char dev_name, void data,
	int (fill_super)(struct super_block , void *, int),
	struct vfsmount *mnt);
	extern struct dentry mount_single(struct file_system_type fs_type,		extern struct dentry mount_single(struct file_system_type fs_type,
	int flags, void *data,		int flags, void *data,
	int (fill_super)(struct super_block , void *, int));		int (fill_super)(struct super_block , void *, int));
	extern int get_sb_single(struct file_system_type *fs_type,
	int flags, void *data,
	int (fill_super)(struct super_block , void *, int),
	struct vfsmount *mnt);
	extern struct dentry mount_nodev(struct file_system_type fs_type,		extern struct dentry mount_nodev(struct file_system_type fs_type,
	int flags, void *data,		int flags, void *data,
	int (fill_super)(struct super_block , void *, int));		int (fill_super)(struct super_block , void *, int));
	extern int get_sb_nodev(struct file_system_type *fs_type,
	int flags, void *data,
	int (fill_super)(struct super_block , void *, int),
	struct vfsmount *mnt);
	void generic_shutdown_super(struct super_block *sb);		void generic_shutdown_super(struct super_block *sb);
	void kill_block_super(struct super_block *sb);		void kill_block_super(struct super_block *sb);
	void kill_anon_super(struct super_block *sb);		void kill_anon_super(struct super_block *sb);