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Commit 9d412a43 authored by Al Viro's avatar Al Viro
Browse files

vfs: split off vfsmount-related parts of vfs_kern_mount() 



new function: mount_fs().  Does all work done by vfs_kern_mount()
except the allocation and filling of vfsmount; returns root dentry
or ERR_PTR().

vfs_kern_mount() switched to using it and taken to fs/namespace.c,
along with its wrappers.

alloc_vfsmnt()/free_vfsmnt() made static.

functions in namespace.c slightly reordered.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent fbe0aa1f

fs/internal.h

+3 −2
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/lglock.h>



struct super_block;

struct file_system_type;

struct linux_binprm;

struct path;
@@ -61,8 +62,6 @@ extern int check_unsafe_exec(struct linux_binprm *); 
extern int copy_mount_options(const void __user *, unsigned long *);

extern int copy_mount_string(const void __user *, char **);



extern void free_vfsmnt(struct vfsmount *);

extern struct vfsmount *alloc_vfsmnt(const char *);

extern unsigned int mnt_get_count(struct vfsmount *mnt);

extern struct vfsmount *__lookup_mnt(struct vfsmount *, struct dentry *, int);

extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
@@ -99,6 +98,8 @@ extern struct file *get_empty_filp(void); 
extern int do_remount_sb(struct super_block *, int, void *, int);

extern void __put_super(struct super_block *sb);

extern void put_super(struct super_block *sb);

extern struct dentry *mount_fs(struct file_system_type *,

			       int, const char *, void *);



/*

 * open.c

fs/namespace.c

+113 −40
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ unsigned int mnt_get_count(struct vfsmount *mnt) 
#endif

}



struct vfsmount *alloc_vfsmnt(const char *name)

static struct vfsmount *alloc_vfsmnt(const char *name)

{

	struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);

	if (mnt) {
@@ -466,7 +466,7 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt) 
	br_write_unlock(vfsmount_lock);

}



void free_vfsmnt(struct vfsmount *mnt)

static void free_vfsmnt(struct vfsmount *mnt)

{

	kfree(mnt->mnt_devname);

	mnt_free_id(mnt);
@@ -670,6 +670,36 @@ static struct vfsmount *skip_mnt_tree(struct vfsmount *p) 
	return p;

}



struct vfsmount *

vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)

{

	struct vfsmount *mnt;

	struct dentry *root;



	if (!type)

		return ERR_PTR(-ENODEV);



	mnt = alloc_vfsmnt(name);

	if (!mnt)

		return ERR_PTR(-ENOMEM);



	if (flags & MS_KERNMOUNT)

		mnt->mnt_flags = MNT_INTERNAL;



	root = mount_fs(type, flags, name, data);

	if (IS_ERR(root)) {

		free_vfsmnt(mnt);

		return ERR_CAST(root);

	}



	mnt->mnt_root = root;

	mnt->mnt_sb = root->d_sb;

	mnt->mnt_mountpoint = mnt->mnt_root;

	mnt->mnt_parent = mnt;

	return mnt;

}

EXPORT_SYMBOL_GPL(vfs_kern_mount);



static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,

					int flag)

{
@@ -1905,7 +1935,81 @@ static int do_move_mount(struct path *path, char *old_name) 
	return err;

}



static int do_add_mount(struct vfsmount *, struct path *, int);

static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)

{

	int err;

	const char *subtype = strchr(fstype, '.');

	if (subtype) {

		subtype++;

		err = -EINVAL;

		if (!subtype[0])

			goto err;

	} else

		subtype = "";



	mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);

	err = -ENOMEM;

	if (!mnt->mnt_sb->s_subtype)

		goto err;

	return mnt;



 err:

	mntput(mnt);

	return ERR_PTR(err);

}



struct vfsmount *

do_kern_mount(const char *fstype, int flags, const char *name, void *data)

{

	struct file_system_type *type = get_fs_type(fstype);

	struct vfsmount *mnt;

	if (!type)

		return ERR_PTR(-ENODEV);

	mnt = vfs_kern_mount(type, flags, name, data);

	if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&

	    !mnt->mnt_sb->s_subtype)

		mnt = fs_set_subtype(mnt, fstype);

	put_filesystem(type);

	return mnt;

}

EXPORT_SYMBOL_GPL(do_kern_mount);



/*

 * add a mount into a namespace's mount tree

 */

static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)

{

	int err;



	mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);



	down_write(&namespace_sem);

	/* Something was mounted here while we slept */

	err = follow_down(path, true);

	if (err < 0)

		goto unlock;



	err = -EINVAL;

	if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))

		goto unlock;



	/* Refuse the same filesystem on the same mount point */

	err = -EBUSY;

	if (path->mnt->mnt_sb == newmnt->mnt_sb &&

	    path->mnt->mnt_root == path->dentry)

		goto unlock;



	err = -EINVAL;

	if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))

		goto unlock;



	newmnt->mnt_flags = mnt_flags;

	err = graft_tree(newmnt, path);



unlock:

	up_write(&namespace_sem);

	return err;

}



/*

 * create a new mount for userspace and request it to be added into the
@@ -1965,43 +2069,6 @@ int finish_automount(struct vfsmount *m, struct path *path) 
	return err;

}



/*

 * add a mount into a namespace's mount tree

 */

static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)

{

	int err;



	mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);



	down_write(&namespace_sem);

	/* Something was mounted here while we slept */

	err = follow_down(path, true);

	if (err < 0)

		goto unlock;



	err = -EINVAL;

	if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))

		goto unlock;



	/* Refuse the same filesystem on the same mount point */

	err = -EBUSY;

	if (path->mnt->mnt_sb == newmnt->mnt_sb &&

	    path->mnt->mnt_root == path->dentry)

		goto unlock;



	err = -EINVAL;

	if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))

		goto unlock;



	newmnt->mnt_flags = mnt_flags;

	err = graft_tree(newmnt, path);



unlock:

	up_write(&namespace_sem);

	return err;

}



/**

 * mnt_set_expiry - Put a mount on an expiration list

 * @mnt: The mount to list.
@@ -2660,3 +2727,9 @@ void put_mnt_ns(struct mnt_namespace *ns) 
	kfree(ns);

}

EXPORT_SYMBOL(put_mnt_ns);



struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)

{

	return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);

}

EXPORT_SYMBOL_GPL(kern_mount_data);

fs/super.c

+16 −80
Original line number Diff line number Diff line
@@ -910,29 +910,18 @@ struct dentry *mount_single(struct file_system_type *fs_type, 
}

EXPORT_SYMBOL(mount_single);



struct vfsmount *

vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)

struct dentry *

mount_fs(struct file_system_type *type, int flags, const char *name, void *data)

{

	struct vfsmount *mnt;

	struct dentry *root;

	struct super_block *sb;

	char *secdata = NULL;

	int error;



	if (!type)

		return ERR_PTR(-ENODEV);



	error = -ENOMEM;

	mnt = alloc_vfsmnt(name);

	if (!mnt)

		goto out;



	if (flags & MS_KERNMOUNT)

		mnt->mnt_flags = MNT_INTERNAL;

	int error = -ENOMEM;



	if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {

		secdata = alloc_secdata();

		if (!secdata)

			goto out_mnt;

			goto out;



		error = security_sb_copy_data(data, secdata);

		if (error)
@@ -944,13 +933,12 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void 
		error = PTR_ERR(root);

		goto out_free_secdata;

	}

	mnt->mnt_root = root;

	mnt->mnt_sb = root->d_sb;

	BUG_ON(!mnt->mnt_sb);

	WARN_ON(!mnt->mnt_sb->s_bdi);

	mnt->mnt_sb->s_flags |= MS_BORN;

	sb = root->d_sb;

	BUG_ON(!sb);

	WARN_ON(!sb->s_bdi);

	sb->s_flags |= MS_BORN;



	error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);

	error = security_sb_kern_mount(sb, flags, secdata);

	if (error)

		goto out_sb;
@@ -961,27 +949,21 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void 
	 * violate this rule. This warning should be either removed or

	 * converted to a BUG() in 2.6.34.

	 */

	WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "

		"negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);

	WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "

		"negative value (%lld)\n", type->name, sb->s_maxbytes);



	mnt->mnt_mountpoint = mnt->mnt_root;

	mnt->mnt_parent = mnt;

	up_write(&mnt->mnt_sb->s_umount);

	up_write(&sb->s_umount);

	free_secdata(secdata);

	return mnt;

	return root;

out_sb:

	dput(mnt->mnt_root);

	deactivate_locked_super(mnt->mnt_sb);

	dput(root);

	deactivate_locked_super(sb);

out_free_secdata:

	free_secdata(secdata);

out_mnt:

	free_vfsmnt(mnt);

out:

	return ERR_PTR(error);

}



EXPORT_SYMBOL_GPL(vfs_kern_mount);



/**

 * freeze_super - lock the filesystem and force it into a consistent state

 * @sb: the super to lock
@@ -1071,49 +1053,3 @@ int thaw_super(struct super_block *sb) 
	return 0;

}

EXPORT_SYMBOL(thaw_super);
 


static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)

{

	int err;

	const char *subtype = strchr(fstype, '.');

	if (subtype) {

		subtype++;

		err = -EINVAL;

		if (!subtype[0])

			goto err;

	} else

		subtype = "";



	mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);

	err = -ENOMEM;

	if (!mnt->mnt_sb->s_subtype)

		goto err;

	return mnt;



 err:

	mntput(mnt);

	return ERR_PTR(err);

}



struct vfsmount *

do_kern_mount(const char *fstype, int flags, const char *name, void *data)

{

	struct file_system_type *type = get_fs_type(fstype);

	struct vfsmount *mnt;

	if (!type)

		return ERR_PTR(-ENODEV);

	mnt = vfs_kern_mount(type, flags, name, data);

	if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&

	    !mnt->mnt_sb->s_subtype)

		mnt = fs_set_subtype(mnt, fstype);

	put_filesystem(type);

	return mnt;

}

EXPORT_SYMBOL_GPL(do_kern_mount);



struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)

{

	return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);

}



EXPORT_SYMBOL_GPL(kern_mount_data);