Here are the patches for the sysfs shadow directories ported to
2.6.21-mm2 in case you want to look at them to spot the issues.
They are extracted from the full netns patchset.
Benjamin
--
B e n j a m i n T h e r y - BULL/DT/Open Software R&D
http://www.bull.com
>From c25e55e214c208c28208605e251148cc7423a0ef Mon Sep 17 00:00:00 2001
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Date: Thu, 5 Apr 2007 00:36:53 -0600
Subject: [PATCH] sysfs: Remove first pass at shadow directory support
While shadow directories appear to be a good idea, the current scheme
of controlling their creation and destruction outside of sysfs appears
to be a locking and maintenance nightmare in the face of sysfs directories
dynamically coming and going. Which can now occur for directories containing
network devices when CONFIG_SYSFS_DEPRECATED is not set.
This patch removes everything from the initial shadow directory support
that allowed the shadow directory creation to be controlled at a higher
level. So except for a few bits of sysfs_rename_dir everything from
commit b592fcfe7f06c15ec11774b5be7ce0de3aa86e73 is now gone.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
fs/sysfs/dir.c | 196 +++++++++--------------------------------------
fs/sysfs/group.c | 1 -
fs/sysfs/inode.c | 10 ---
fs/sysfs/mount.c | 2 +-
fs/sysfs/sysfs.h | 5 -
include/linux/kobject.h | 4 -
include/linux/sysfs.h | 24 +-----
lib/kobject.c | 43 +---------
8 files changed, 45 insertions(+), 240 deletions(-)
Index: linux-2.6.21-mm2-netns1/fs/sysfs/dir.c
===================================================================
--- linux-2.6.21-mm2-netns1.orig/fs/sysfs/dir.c
+++ linux-2.6.21-mm2-netns1/fs/sysfs/dir.c
@@ -272,10 +272,9 @@ int sysfs_create_subdir(struct kobject *
/**
* sysfs_create_dir - create a directory for an object.
* @kobj: object we're creating directory for.
- * @shadow_parent: parent parent object.
*/
-int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
+int sysfs_create_dir(struct kobject * kobj)
{
struct dentry * dentry = NULL;
struct dentry * parent;
@@ -283,9 +282,7 @@ int sysfs_create_dir(struct kobject * ko
BUG_ON(!kobj);
- if (shadow_parent)
- parent = shadow_parent;
- else if (kobj->parent)
+ if (kobj->parent)
parent = kobj->parent->dentry;
else if (sysfs_mount && sysfs_mount->mnt_sb)
parent = sysfs_mount->mnt_sb->s_root;
@@ -444,35 +441,34 @@ void sysfs_remove_dir(struct kobject * k
__sysfs_remove_dir(d);
}
-int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
- const char *new_name)
+int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
{
struct sysfs_dirent *sd = kobj->dentry->d_fsdata;
- struct sysfs_dirent *parent_sd = new_parent->d_fsdata;
- struct dentry *new_dentry;
+ struct sysfs_dirent *parent_sd;
+ struct inode * inode;
+ struct dentry * new_dentry, * old_parent, * new_parent;
char *dup_name;
int error;
- if (!new_parent)
- return -EFAULT;
+ if (!kobj->parent)
+ return -EINVAL;
+
+ old_parent = dget(kobj->dentry->d_parent);
+ inode = old_parent->d_inode;
down_write(&sysfs_rename_sem);
- mutex_lock(&new_parent->d_inode->i_mutex);
+ mutex_lock(&inode->i_mutex);
+ new_parent = kobj->dentry->d_parent;
+ parent_sd = new_parent->d_fsdata;
new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
if (IS_ERR(new_dentry)) {
error = PTR_ERR(new_dentry);
goto out_unlock;
}
- /* By allowing two different directories with the same
- * d_parent we allow this routine to move between different
- * shadows of the same directory
- */
error = -EINVAL;
- if (kobj->dentry->d_parent->d_inode != new_parent->d_inode ||
- new_dentry->d_parent->d_inode != new_parent->d_inode ||
- new_dentry == kobj->dentry)
+ if (new_dentry == kobj->dentry)
goto out_dput;
error = -EEXIST;
@@ -509,7 +505,7 @@ int sysfs_rename_dir(struct kobject * ko
out_dput:
dput(new_dentry);
out_unlock:
- mutex_unlock(&new_parent->d_inode->i_mutex);
+ mutex_unlock(&inode->i_mutex);
up_write(&sysfs_rename_sem);
return error;
}
@@ -692,98 +688,6 @@ static loff_t sysfs_dir_lseek(struct fil
return offset;
}
-
-/**
- * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
- * @kobj: object we're creating shadow of.
- */
-
-int sysfs_make_shadowed_dir(struct kobject *kobj,
- void * (*follow_link)(struct dentry *, struct nameidata *))
-{
- struct inode *inode;
- struct inode_operations *i_op;
-
- inode = kobj->dentry->d_inode;
- if (inode->i_op != &sysfs_dir_inode_operations)
- return -EINVAL;
-
- i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
- if (!i_op)
- return -ENOMEM;
-
- memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
- i_op->follow_link = follow_link;
-
- /* Locking of inode->i_op?
- * Since setting i_op is a single word write and they
- * are atomic we should be ok here.
- */
- inode->i_op = i_op;
- return 0;
-}
-
-/**
- * sysfs_create_shadow_dir - create a shadow directory for an object.
- * @kobj: object we're creating directory for.
- *
- * sysfs_make_shadowed_dir must already have been called on this
- * directory.
- */
-
-struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
-{
- struct dentry *dir = kobj->dentry;
- struct inode *inode = dir->d_inode;
- struct dentry *parent = dir->d_parent;
- struct sysfs_dirent *parent_sd = parent->d_fsdata;
- struct dentry *shadow;
- struct sysfs_dirent *sd;
-
- shadow = ERR_PTR(-EINVAL);
- if (!sysfs_is_shadowed_inode(inode))
- goto out;
-
- shadow = d_alloc(parent, &dir->d_name);
- if (!shadow)
- goto nomem;
-
- sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR);
- if (!sd)
- goto nomem;
- sd->s_elem.dir.kobj = kobj;
- /* point to parent_sd but don't attach to it */
- sd->s_parent = sysfs_get(parent_sd);
- sysfs_attach_dirent(sd, NULL, shadow);
-
- d_instantiate(shadow, igrab(inode));
- inc_nlink(inode);
- inc_nlink(parent->d_inode);
-
- dget(shadow); /* Extra count - pin the dentry in core */
-
-out:
- return shadow;
-nomem:
- dput(shadow);
- shadow = ERR_PTR(-ENOMEM);
- goto out;
-}
-
-/**
- * sysfs_remove_shadow_dir - remove an object's directory.
- * @shadow: dentry of shadow directory
- *
- * The only thing special about this is that we remove any files in
- * the directory before we remove the directory, and we've inlined
- * what used to be sysfs_rmdir() below, instead of calling separately.
- */
-
-void sysfs_remove_shadow_dir(struct dentry *shadow)
-{
- __sysfs_remove_dir(shadow);
-}
-
const struct file_operations sysfs_dir_operations = {
.open = sysfs_dir_open,
.release = sysfs_dir_close,
Index: linux-2.6.21-mm2-netns1/fs/sysfs/group.c
===================================================================
--- linux-2.6.21-mm2-netns1.orig/fs/sysfs/group.c
+++ linux-2.6.21-mm2-netns1/fs/sysfs/group.c
@@ -13,7 +13,6 @@
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
-#include <linux/fs.h>
#include <asm/semaphore.h>
#include "sysfs.h"
Index: linux-2.6.21-mm2-netns1/fs/sysfs/inode.c
===================================================================
--- linux-2.6.21-mm2-netns1.orig/fs/sysfs/inode.c
+++ linux-2.6.21-mm2-netns1/fs/sysfs/inode.c
@@ -33,16 +33,6 @@ static const struct inode_operations sys
.setattr = sysfs_setattr,
};
-void sysfs_delete_inode(struct inode *inode)
-{
- /* Free the shadowed directory inode operations */
- if (sysfs_is_shadowed_inode(inode)) {
- kfree(inode->i_op);
- inode->i_op = NULL;
- }
- return generic_delete_inode(inode);
-}
-
int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
{
struct inode * inode = dentry->d_inode;
Index: linux-2.6.21-mm2-netns1/fs/sysfs/mount.c
===================================================================
--- linux-2.6.21-mm2-netns1.orig/fs/sysfs/mount.c
+++ linux-2.6.21-mm2-netns1/fs/sysfs/mount.c
@@ -19,7 +19,7 @@ struct kmem_cache *sysfs_dir_cachep;
static const struct super_operations sysfs_ops = {
.statfs = simple_statfs,
- .drop_inode = sysfs_delete_inode,
+ .drop_inode = generic_delete_inode,
};
static struct sysfs_dirent sysfs_root = {
Index: linux-2.6.21-mm2-netns1/fs/sysfs/sysfs.h
===================================================================
--- linux-2.6.21-mm2-netns1.orig/fs/sysfs/sysfs.h
+++ linux-2.6.21-mm2-netns1/fs/sysfs/sysfs.h
@@ -56,7 +56,6 @@ enum sysfs_s_active_class
extern struct vfsmount * sysfs_mount;
extern struct kmem_cache *sysfs_dir_cachep;
-extern void sysfs_delete_inode(struct inode *inode);
extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *);
extern int sysfs_create(struct sysfs_dirent *sd, struct dentry *dentry,
int mode, int (*init)(struct inode *));
@@ -192,7 +191,3 @@ static inline void sysfs_deactivate(stru
rwsem_release(&sd->s_active.dep_map, 1, _RET_IP_);
}
-static inline int sysfs_is_shadowed_inode(struct inode *inode)
-{
- return S_ISDIR(inode->i_mode) && inode->i_op->follow_link;
-}
Index: linux-2.6.21-mm2-netns1/include/linux/kobject.h
===================================================================
--- linux-2.6.21-mm2-netns1.orig/include/linux/kobject.h
+++ linux-2.6.21-mm2-netns1/include/linux/kobject.h
@@ -71,13 +71,9 @@ extern void kobject_init(struct kobject
extern void kobject_cleanup(struct kobject *);
extern int __must_check kobject_add(struct kobject *);
-extern int __must_check kobject_shadow_add(struct kobject *, struct dentry *);
extern void kobject_del(struct kobject *);
extern int __must_check kobject_rename(struct kobject *, const char *new_name);
-extern int __must_check kobject_shadow_rename(struct kobject *kobj,
- struct dentry *new_parent,
- const char *new_name);
extern int __must_check kobject_move(struct kobject *, struct kobject *);
extern int __must_check kobject_register(struct kobject *);
Index: linux-2.6.21-mm2-netns1/include/linux/sysfs.h
===================================================================
--- linux-2.6.21-mm2-netns1.orig/include/linux/sysfs.h
+++ linux-2.6.21-mm2-netns1/include/linux/sysfs.h
@@ -17,8 +17,6 @@
struct kobject;
struct module;
-struct nameidata;
-struct dentry;
/* FIXME
* The *owner field is no longer used, but leave around
@@ -88,13 +86,13 @@ extern int sysfs_schedule_callback(struc
void (*func)(void *), void *data, struct module *owner);
extern int __must_check
-sysfs_create_dir(struct kobject *, struct dentry *);
+sysfs_create_dir(struct kobject *);
extern void
sysfs_remove_dir(struct kobject *);
extern int __must_check
-sysfs_rename_dir(struct kobject *, struct dentry *, const char *new_name);
+sysfs_rename_dir(struct kobject *, const char *new_name);
extern int __must_check
sysfs_move_dir(struct kobject *, struct kobject *);
@@ -131,12 +129,6 @@ void sysfs_remove_file_from_group(struct
void sysfs_notify(struct kobject * k, char *dir, char *attr);
-
-extern int sysfs_make_shadowed_dir(struct kobject *kobj,
- void * (*follow_link)(struct dentry *, struct nameidata *));
-extern struct dentry *sysfs_create_shadow_dir(struct kobject *kobj);
-extern void sysfs_remove_shadow_dir(struct dentry *dir);
-
extern int __must_check sysfs_init(void);
#else /* CONFIG_SYSFS */
@@ -147,7 +139,7 @@ static inline int sysfs_schedule_callbac
return -ENOSYS;
}
-static inline int sysfs_create_dir(struct kobject * k, struct dentry *shadow)
+static inline int sysfs_create_dir(struct kobject * k)
{
return 0;
}
@@ -157,9 +149,7 @@ static inline void sysfs_remove_dir(stru
;
}
-static inline int sysfs_rename_dir(struct kobject * k,
- struct dentry *new_parent,
- const char *new_name)
+static inline int sysfs_rename_dir(struct kobject * k, const char *new_name)
{
return 0;
}
@@ -234,12 +224,6 @@ static inline void sysfs_notify(struct k
{
}
-static inline int sysfs_make_shadowed_dir(struct kobject *kobj,
- void * (*follow_link)(struct dentry *, struct nameidata *))
-{
- return 0;
-}
-
static inline int __must_check sysfs_init(void)
{
return 0;
Index: linux-2.6.21-mm2-netns1/lib/kobject.c
===================================================================
--- linux-2.6.21-mm2-netns1.orig/lib/kobject.c
+++ linux-2.6.21-mm2-netns1/lib/kobject.c
@@ -46,11 +46,11 @@ static int populate_dir(struct kobject *
return error;
}
-static int create_dir(struct kobject * kobj, struct dentry *shadow_parent)
+static int create_dir(struct kobject * kobj)
{
int error = 0;
if (kobject_name(kobj)) {
- error = sysfs_create_dir(kobj, shadow_parent);
+ error = sysfs_create_dir(kobj);
if (!error) {
if ((error = populate_dir(kobj)))
sysfs_remove_dir(kobj);
@@ -203,10 +203,9 @@ static void unlink(struct kobject * kobj
/**
* kobject_shadow_add - add an object to the hierarchy.
* @kobj: object.
- * @shadow_parent: sysfs directory to add to.
*/
-int kobject_shadow_add(struct kobject * kobj, struct dentry *shadow_parent)
+int kobject_add(struct kobject * kobj)
{
int error = 0;
struct kobject * parent;
@@ -238,7 +237,7 @@ int kobject_shadow_add(struct kobject *
kobj->parent = parent;
}
- error = create_dir(kobj, shadow_parent);
+ error = create_dir(kobj);
if (error) {
/* unlink does the kobject_put() for us */
unlink(kobj);
@@ -259,15 +258,6 @@ int kobject_shadow_add(struct kobject *
return error;
}
-/**
- * kobject_add - add an object to the hierarchy.
- * @kobj: object.
- */
-int kobject_add(struct kobject * kobj)
-{
- return kobject_shadow_add(kobj, NULL);
-}
-
/**
* kobject_register - initialize and add an object.
@@ -363,8 +353,6 @@ int kobject_rename(struct kobject * kobj
kobj = kobject_get(kobj);
if (!kobj)
return -EINVAL;
- if (!kobj->parent)
- return -EINVAL;
devpath = kobject_get_path(kobj, GFP_KERNEL);
if (!devpath) {
@@ -382,7 +370,7 @@ int kobject_rename(struct kobject * kobj
/* Note : if we want to send the new name alone, not the full path,
* we could probably use kobject_name(kobj); */
- error = sysfs_rename_dir(kobj, kobj->parent->dentry, new_name);
+ error = sysfs_rename_dir(kobj, new_name);
/* This function is mostly/only used for network interface.
* Some hotplug package track interfaces by their name and
@@ -399,27 +387,6 @@ out:
}
/**
- * kobject_rename - change the name of an object
- * @kobj: object in question.
- * @new_parent: object's new parent
- * @new_name: object's new name
- */
-
-int kobject_shadow_rename(struct kobject * kobj, struct dentry *new_parent,
- const char *new_name)
-{
- int error = 0;
-
- kobj = kobject_get(kobj);
- if (!kobj)
- return -EINVAL;
- error = sysfs_rename_dir(kobj, new_parent, new_name);
- kobject_put(kobj);
-
- return error;
-}
-
-/**
* kobject_move - move object to another parent
* @kobj: object in question.
* @new_parent: object's new parent (can be NULL)
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