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authorTejun Heo <tj@kernel.org>2013-09-11 22:29:07 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 15:30:22 -0700
commitcb26a311578e67769e92a39a0a63476533cb7e12 (patch)
tree13a1c59bdf23abdb063d1bc4a8cc1679e36dcd38 /fs/sysfs/dir.c
parent4b30ee58ee64c64f59fd876e4afa6ed82caef3a4 (diff)
downloadlinux-cb26a311578e67769e92a39a0a63476533cb7e12.tar.bz2
sysfs: drop kobj_ns_type handling
The way namespace tags are implemented in sysfs is more complicated than necessary. As each tag is a pointer value and required to be non-NULL under a namespace enabled parent, there's no need to record separately what type each tag is or where namespace is enabled. If multiple namespace types are needed, which currently aren't, we can simply compare the tag to a set of allowed tags in the superblock assuming that the tags, being pointers, won't have the same value across multiple types. Also, whether to filter by namespace tag or not can be trivially determined by whether the node has any tagged children or not. This patch rips out kobj_ns_type handling from sysfs. sysfs no longer cares whether specific type of namespace is enabled or not. If a sysfs_dirent has a non-NULL tag, the parent is marked as needing namespace filtering and the value is tested against the allowed set of tags for the superblock (currently only one but increasing this number isn't difficult) and the sysfs_dirent is ignored if it doesn't match. This removes most kobject namespace knowledge from sysfs proper which will enable proper separation and layering of sysfs. The namespace sanity checks in fs/sysfs/dir.c are replaced by the new sanity check in kobject_namespace(). As this is the only place ktype->namespace() is called for sysfs, this doesn't weaken the sanity check significantly. I omitted converting the sanity check in sysfs_do_create_link_sd(). While the check can be shifted to upper layer, mistakes there are well contained and should be easily visible anyway. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/sysfs/dir.c')
-rw-r--r--fs/sysfs/dir.c90
1 files changed, 25 insertions, 65 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 878ac3afe1b8..1dfb4aaf9446 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -111,6 +111,11 @@ static int sysfs_link_sibling(struct sysfs_dirent *sd)
/* add new node and rebalance the tree */
rb_link_node(&sd->s_rb, parent, node);
rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
+
+ /* if @sd has ns tag, mark the parent to enable ns filtering */
+ if (sd->s_ns)
+ sd->s_parent->s_flags |= SYSFS_FLAG_HAS_NS;
+
return 0;
}
@@ -130,6 +135,13 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
sd->s_parent->s_dir.subdirs--;
rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
+
+ /*
+ * Either all or none of the children have tags. Clearing HAS_NS
+ * when there's no child left is enough to keep the flag synced.
+ */
+ if (RB_EMPTY_ROOT(&sd->s_parent->s_dir.children))
+ sd->s_parent->s_flags &= ~SYSFS_FLAG_HAS_NS;
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -297,7 +309,6 @@ static int sysfs_dentry_delete(const struct dentry *dentry)
static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
{
struct sysfs_dirent *sd;
- int type;
if (flags & LOOKUP_RCU)
return -ECHILD;
@@ -318,13 +329,8 @@ static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
goto out_bad;
/* The sysfs dirent has been moved to a different namespace */
- type = KOBJ_NS_TYPE_NONE;
- if (sd->s_parent) {
- type = sysfs_ns_type(sd->s_parent);
- if (type != KOBJ_NS_TYPE_NONE &&
- sysfs_info(dentry->d_sb)->ns[type] != sd->s_ns)
- goto out_bad;
- }
+ if (sd->s_ns && sd->s_ns != sysfs_info(dentry->d_sb)->ns)
+ goto out_bad;
mutex_unlock(&sysfs_mutex);
out_valid:
@@ -445,13 +451,6 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
struct sysfs_inode_attrs *ps_iattr;
int ret;
- if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) {
- WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
- sysfs_ns_type(acxt->parent_sd) ? "required" : "invalid",
- acxt->parent_sd->s_name, sd->s_name);
- return -EINVAL;
- }
-
sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
sd->s_parent = sysfs_get(acxt->parent_sd);
@@ -613,13 +612,6 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
struct rb_node *node = parent_sd->s_dir.children.rb_node;
unsigned int hash;
- if (!!sysfs_ns_type(parent_sd) != !!ns) {
- WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
- sysfs_ns_type(parent_sd) ? "required" : "invalid",
- parent_sd->s_name, name);
- return NULL;
- }
-
hash = sysfs_name_hash(ns, name);
while (node) {
struct sysfs_dirent *sd;
@@ -667,8 +659,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
EXPORT_SYMBOL_GPL(sysfs_get_dirent);
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
- enum kobj_ns_type type, const void *ns, const char *name,
- struct sysfs_dirent **p_sd)
+ const void *ns, const char *name, struct sysfs_dirent **p_sd)
{
umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
struct sysfs_addrm_cxt acxt;
@@ -680,7 +671,6 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
if (!sd)
return -ENOMEM;
- sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
sd->s_ns = ns;
sd->s_dir.kobj = kobj;
@@ -700,33 +690,7 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
int sysfs_create_subdir(struct kobject *kobj, const char *name,
struct sysfs_dirent **p_sd)
{
- return create_dir(kobj, kobj->sd,
- KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
-}
-
-/**
- * sysfs_read_ns_type: return associated ns_type
- * @kobj: the kobject being queried
- *
- * Each kobject can be tagged with exactly one namespace type
- * (i.e. network or user). Return the ns_type associated with
- * this object if any
- */
-static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
-{
- const struct kobj_ns_type_operations *ops;
- enum kobj_ns_type type;
-
- ops = kobj_child_ns_ops(kobj);
- if (!ops)
- return KOBJ_NS_TYPE_NONE;
-
- type = ops->type;
- BUG_ON(type <= KOBJ_NS_TYPE_NONE);
- BUG_ON(type >= KOBJ_NS_TYPES);
- BUG_ON(!kobj_ns_type_registered(type));
-
- return type;
+ return create_dir(kobj, kobj->sd, NULL, name, p_sd);
}
/**
@@ -736,7 +700,6 @@ static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
*/
int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
{
- enum kobj_ns_type type;
struct sysfs_dirent *parent_sd, *sd;
int error = 0;
@@ -750,9 +713,7 @@ int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
if (!parent_sd)
return -ENOENT;
- type = sysfs_read_ns_type(kobj);
-
- error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
+ error = create_dir(kobj, parent_sd, ns, kobject_name(kobj), &sd);
if (!error)
kobj->sd = sd;
return error;
@@ -766,13 +727,12 @@ static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
struct sysfs_dirent *parent_sd = parent->d_fsdata;
struct sysfs_dirent *sd;
struct inode *inode;
- enum kobj_ns_type type;
- const void *ns;
+ const void *ns = NULL;
mutex_lock(&sysfs_mutex);
- type = sysfs_ns_type(parent_sd);
- ns = sysfs_info(dir->i_sb)->ns[type];
+ if (parent_sd->s_flags & SYSFS_FLAG_HAS_NS)
+ ns = sysfs_info(dir->i_sb)->ns;
sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
@@ -995,15 +955,15 @@ static int sysfs_readdir(struct file *file, struct dir_context *ctx)
struct dentry *dentry = file->f_path.dentry;
struct sysfs_dirent *parent_sd = dentry->d_fsdata;
struct sysfs_dirent *pos = file->private_data;
- enum kobj_ns_type type;
- const void *ns;
-
- type = sysfs_ns_type(parent_sd);
- ns = sysfs_info(dentry->d_sb)->ns[type];
+ const void *ns = NULL;
if (!dir_emit_dots(file, ctx))
return 0;
mutex_lock(&sysfs_mutex);
+
+ if (parent_sd->s_flags & SYSFS_FLAG_HAS_NS)
+ ns = sysfs_info(dentry->d_sb)->ns;
+
for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos);
pos;
pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) {