Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin

* 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits)
  fs: scale mntget/mntput
  fs: rename vfsmount counter helpers
  fs: implement faster dentry memcmp
  fs: prefetch inode data in dcache lookup
  fs: improve scalability of pseudo filesystems
  fs: dcache per-inode inode alias locking
  fs: dcache per-bucket dcache hash locking
  bit_spinlock: add required includes
  kernel: add bl_list
  xfs: provide simple rcu-walk ACL implementation
  btrfs: provide simple rcu-walk ACL implementation
  ext2,3,4: provide simple rcu-walk ACL implementation
  fs: provide simple rcu-walk generic_check_acl implementation
  fs: provide rcu-walk aware permission i_ops
  fs: rcu-walk aware d_revalidate method
  fs: cache optimise dentry and inode for rcu-walk
  fs: dcache reduce branches in lookup path
  fs: dcache remove d_mounted
  fs: fs_struct use seqlock
  fs: rcu-walk for path lookup
  ...

3 files changed, 16 insertions, 7 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 7e54bac8c4b0..ea9120a830d8 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -231,7 +231,7 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
                 goto repeat;
 }
 
-static int sysfs_dentry_delete(struct dentry *dentry)
+static int sysfs_dentry_delete(const struct dentry *dentry)
 {
         struct sysfs_dirent *sd = dentry->d_fsdata;
         return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
@@ -239,9 +239,13 @@ static int sysfs_dentry_delete(struct dentry *dentry)
 
 static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-        struct sysfs_dirent *sd = dentry->d_fsdata;
+        struct sysfs_dirent *sd;
         int is_dir;
 
+        if (nd->flags & LOOKUP_RCU)
+                return -ECHILD;
+
+        sd = dentry->d_fsdata;
         mutex_lock(&sysfs_mutex);
 
         /* The sysfs dirent has been deleted */
@@ -701,7 +705,7 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
         /* instantiate and hash dentry */
         ret = d_find_alias(inode);
         if (!ret) {
-                dentry->d_op = &sysfs_dentry_ops;
+                d_set_d_op(dentry, &sysfs_dentry_ops);
                 dentry->d_fsdata = sysfs_get(sd);
                 d_add(dentry, inode);
         } else {
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index cffb1fd8ba33..30ac27345586 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -348,13 +348,18 @@ int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const cha
                 return -ENOENT;
 }
 
-int sysfs_permission(struct inode *inode, int mask)
+int sysfs_permission(struct inode *inode, int mask, unsigned int flags)
 {
-        struct sysfs_dirent *sd = inode->i_private;
+        struct sysfs_dirent *sd;
+
+        if (flags & IPERM_FLAG_RCU)
+                return -ECHILD;
+
+        sd = inode->i_private;
 
         mutex_lock(&sysfs_mutex);
         sysfs_refresh_inode(sd, inode);
         mutex_unlock(&sysfs_mutex);
 
-        return generic_permission(inode, mask, NULL);
+        return generic_permission(inode, mask, flags, NULL);
 }
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index d9be60a2e956..ffaaa816bfba 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -200,7 +200,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd)
 struct inode *sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd);
 void sysfs_evict_inode(struct inode *inode);
 int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr);
-int sysfs_permission(struct inode *inode, int mask);
+int sysfs_permission(struct inode *inode, int mask, unsigned int flags);
 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
 int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat);
 int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,