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Commit df394fb5 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
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sysfs, kernfs: make super_blocks bind to different kernfs_roots 



kernfs is being updated to allow multiple sysfs_dirent hierarchies so
that it can also be used by other users.  Currently, sysfs
super_blocks are always attached to one kernfs_root - sysfs_root - and
distinguished only by their namespace tags.

This patch adds sysfs_super_info->root and update
sysfs_fill/test_super() so that super_blocks are identified by the
combination of both the associated kernfs_root and namespace tag.
This allows mounting different kernfs hierarchies.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bc755553

fs/sysfs/mount.c

+6 −4
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ struct sysfs_dirent *sysfs_root_sd; 


static int sysfs_fill_super(struct super_block *sb)

{

	struct sysfs_super_info *info = sysfs_info(sb);

	struct inode *inode;

	struct dentry *root;
@@ -48,7 +49,7 @@ static int sysfs_fill_super(struct super_block *sb) 


	/* get root inode, initialize and unlock it */

	mutex_lock(&sysfs_mutex);

	inode = sysfs_get_inode(sb, sysfs_root_sd);

	inode = sysfs_get_inode(sb, info->root->sd);

	mutex_unlock(&sysfs_mutex);

	if (!inode) {

		pr_debug("sysfs: could not get root inode\n");
@@ -61,8 +62,8 @@ static int sysfs_fill_super(struct super_block *sb) 
		pr_debug("%s: could not get root dentry!\n", __func__);

		return -ENOMEM;

	}

	kernfs_get(sysfs_root_sd);

	root->d_fsdata = sysfs_root_sd;

	kernfs_get(info->root->sd);

	root->d_fsdata = info->root->sd;

	sb->s_root = root;

	sb->s_d_op = &sysfs_dentry_ops;

	return 0;
@@ -73,7 +74,7 @@ static int sysfs_test_super(struct super_block *sb, void *data) 
	struct sysfs_super_info *sb_info = sysfs_info(sb);

	struct sysfs_super_info *info = data;



	return sb_info->ns == info->ns;

	return sb_info->root == info->root && sb_info->ns == info->ns;

}



static int sysfs_set_super(struct super_block *sb, void *data)
@@ -110,6 +111,7 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type, 
	if (!info)

		return ERR_PTR(-ENOMEM);



	info->root = sysfs_root;

	info->ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);



	sb = sget(fs_type, sysfs_test_super, sysfs_set_super, flags, info);

fs/sysfs/sysfs.h

+6 −0
Original line number Diff line number Diff line
@@ -19,6 +19,12 @@ 
 */



struct sysfs_super_info {

	/*

	 * The root associated with this super_block.  Each super_block is

	 * identified by the root and ns it's associated with.

	 */

	struct kernfs_root	*root;



	/*

	 * Each sb is associated with one namespace tag, currently the network

	 * namespace of the task which mounted this sysfs instance.  If multiple