1 files changed, 21 insertions, 5 deletions

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;
 }