From df394fb56c64244b30b442e9e02de1a2d9c5a98b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 28 Nov 2013 14:54:42 -0500 Subject: [PATCH] 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: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/mount.c | 10 ++++++---- fs/sysfs/sysfs.h | 6 ++++++ 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 0b5661b462f7..f143b203a7e6 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -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); diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 2b217cef90be..93b4b68458ad 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -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