5 files changed, 47 insertions, 20 deletions

diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index c16a93c353c0..98022e41cda1 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -10,6 +10,7 @@
 
 #include <linux/errno.h>
 #include <linux/fs.h>
+#include <linux/kernel.h>
 #include <linux/kobject.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -176,7 +177,6 @@ const struct file_operations bin_fops = {
  *      sysfs_create_bin_file - create binary file for object.
  *      @kobj:  object.
  *      @attr:  attribute descriptor.
- *
  */
 
 int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
@@ -191,13 +191,16 @@ int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
  *      sysfs_remove_bin_file - remove binary file for object.
  *      @kobj:  object.
  *      @attr:  attribute descriptor.
- *
  */
 
-int sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
+void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 {
-        sysfs_hash_and_remove(kobj->dentry,attr->attr.name);
-        return 0;
+        if (sysfs_hash_and_remove(kobj->dentry, attr->attr.name) < 0) {
+                printk(KERN_ERR "%s: "
+                        "bad dentry or inode or no such file: \"%s\"\n",
+                        __FUNCTION__, attr->attr.name);
+                dump_stack();
+        }
 }
 
 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 610b5bdbe75b..5f3d725d1125 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -43,7 +43,7 @@ static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
 
         memset(sd, 0, sizeof(*sd));
         atomic_set(&sd->s_count, 1);
-        atomic_set(&sd->s_event, 0);
+        atomic_set(&sd->s_event, 1);
         INIT_LIST_HEAD(&sd->s_children);
         list_add(&sd->s_sibling, &parent_sd->s_children);
         sd->s_element = element;
@@ -430,10 +430,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
                         i++;
                         /* fallthrough */
                 default:
-                        if (filp->f_pos == 2) {
-                                list_del(q);
-                                list_add(q, &parent_sd->s_children);
-                        }
+                        if (filp->f_pos == 2)
+                                list_move(q, &parent_sd->s_children);
+
                         for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
                                 struct sysfs_dirent *next;
                                 const char * name;
@@ -455,8 +454,7 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
                                                  dt_type(next)) < 0)
                                         return 0;
 
-                                list_del(q);
-                                list_add(q, p);
+                                list_move(q, p);
                                 p = q;
                                 filp->f_pos++;
                         }
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index f0b347bd12ca..e79e38d52c00 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -12,11 +12,12 @@
 #include <linux/namei.h>
 #include <linux/backing-dev.h>
 #include <linux/capability.h>
+#include <linux/errno.h>
 #include "sysfs.h"
 
 extern struct super_block * sysfs_sb;
 
-static struct address_space_operations sysfs_aops = {
+static const struct address_space_operations sysfs_aops = {
         .readpage       = simple_readpage,
         .prepare_write  = simple_prepare_write,
         .commit_write   = simple_commit_write
@@ -109,15 +110,26 @@ static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
         inode->i_ctime = iattr->ia_ctime;
 }
 
+
+/*
+ * sysfs has a different i_mutex lock order behavior for i_mutex than other
+ * filesystems; sysfs i_mutex is called in many places with subsystem locks
+ * held. At the same time, many of the VFS locking rules do not apply to
+ * sysfs at all (cross directory rename for example). To untangle this mess
+ * (which gives false positives in lockdep), we're giving sysfs inodes their
+ * own class for i_mutex.
+ */
+static struct lock_class_key sysfs_inode_imutex_key;
+
 struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd)
 {
         struct inode * inode = new_inode(sysfs_sb);
         if (inode) {
-                inode->i_blksize = PAGE_CACHE_SIZE;
                 inode->i_blocks = 0;
                 inode->i_mapping->a_ops = &sysfs_aops;
                 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
                 inode->i_op = &sysfs_inode_operations;
+                lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
 
                 if (sd->s_iattr) {
                         /* sysfs_dirent has non-default attributes
@@ -222,17 +234,18 @@ void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
         }
 }
 
-void sysfs_hash_and_remove(struct dentry * dir, const char * name)
+int sysfs_hash_and_remove(struct dentry * dir, const char * name)
 {
         struct sysfs_dirent * sd;
         struct sysfs_dirent * parent_sd;
+        int found = 0;
 
         if (!dir)
-                return;
+                return -ENOENT;
 
         if (dir->d_inode == NULL)
                 /* no inode means this hasn't been made visible yet */
-                return;
+                return -ENOENT;
 
         parent_sd = dir->d_fsdata;
         mutex_lock(&dir->d_inode->i_mutex);
@@ -243,8 +256,11 @@ void sysfs_hash_and_remove(struct dentry * dir, const char * name)
                         list_del_init(&sd->s_sibling);
                         sysfs_drop_dentry(sd, dir);
                         sysfs_put(sd);
+                        found = 1;
                         break;
                 }
         }
         mutex_unlock(&dir->d_inode->i_mutex);
+
+        return found ? 0 : -ENOENT;
 }
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index d2eac3ceed5f..f50e3cc2ded8 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -3,6 +3,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/mount.h>
 #include <linux/module.h>
 #include <linux/kobject.h>
 #include <linux/namei.h>
@@ -82,10 +83,19 @@ exit1:
  */
 int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char * name)
 {
-        struct dentry * dentry = kobj->dentry;
+        struct dentry *dentry = NULL;
         int error = -EEXIST;
 
-        BUG_ON(!kobj || !kobj->dentry || !name);
+        BUG_ON(!name);
+
+        if (!kobj) {
+                if (sysfs_mount && sysfs_mount->mnt_sb)
+                        dentry = sysfs_mount->mnt_sb->s_root;
+        } else
+                dentry = kobj->dentry;
+
+        if (!dentry)
+                return -EFAULT;
 
         mutex_lock(&dentry->d_inode->i_mutex);
         if (!sysfs_dirent_exist(dentry->d_fsdata, name))
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 3651ffb5ec09..6f3d6bd52887 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -10,7 +10,7 @@ extern int sysfs_make_dirent(struct sysfs_dirent *, struct dentry *, void *,
                                 umode_t, int);
 
 extern int sysfs_add_file(struct dentry *, const struct attribute *, int);
-extern void sysfs_hash_and_remove(struct dentry * dir, const char * name);
+extern int sysfs_hash_and_remove(struct dentry * dir, const char * name);
 extern struct sysfs_dirent *sysfs_find(struct sysfs_dirent *dir, const char * name);
 
 extern int sysfs_create_subdir(struct kobject *, const char *, struct dentry **);