Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/hch/vfs-queue

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/hch/vfs-queue:
  vfs: add d_prune dentry operation
  vfs: protect i_nlink
  filesystems: add set_nlink()
  filesystems: add missing nlink wrappers
  logfs: remove unnecessary nlink setting
  ocfs2: remove unnecessary nlink setting
  jfs: remove unnecessary nlink setting
  hypfs: remove unnecessary nlink setting
  vfs: ignore error on forced remount
  readlinkat: ensure we return ENOENT for the empty pathname for normal lookups
  vfs: fix dentry leak in simple_fill_super()

3 files changed, 33 insertions, 7 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 62157c03caf7..4df926199369 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -165,6 +165,7 @@ struct dentry_operations {
                         unsigned int, const char *, const struct qstr *);
         int (*d_delete)(const struct dentry *);
         void (*d_release)(struct dentry *);
+        void (*d_prune)(struct dentry *);
         void (*d_iput)(struct dentry *, struct inode *);
         char *(*d_dname)(struct dentry *, char *, int);
         struct vfsmount *(*d_automount)(struct path *);
@@ -184,8 +185,9 @@ struct dentry_operations {
 #define DCACHE_OP_COMPARE       0x0002
 #define DCACHE_OP_REVALIDATE    0x0004
 #define DCACHE_OP_DELETE        0x0008
+#define DCACHE_OP_PRUNE         0x0010
 
-#define DCACHE_DISCONNECTED     0x0010
+#define DCACHE_DISCONNECTED     0x0020
      /* This dentry is possibly not currently connected to the dcache tree, in
       * which case its parent will either be itself, or will have this flag as
       * well.  nfsd will not use a dentry with this bit set, but will first
@@ -196,8 +198,8 @@ struct dentry_operations {
       * dentry into place and return that dentry rather than the passed one,
       * typically using d_splice_alias. */
 
-#define DCACHE_REFERENCED       0x0020  /* Recently used, don't discard. */
-#define DCACHE_RCUACCESS        0x0040  /* Entry has ever been RCU-visible */
+#define DCACHE_REFERENCED       0x0040  /* Recently used, don't discard. */
+#define DCACHE_RCUACCESS        0x0080  /* Entry has ever been RCU-visible */
 
 #define DCACHE_CANT_MOUNT       0x0100
 #define DCACHE_GENOCIDE         0x0200
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 78af9385f415..0c4df261af7e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -768,7 +768,17 @@ struct inode {
 
         /* Stat data, not accessed from path walking */
         unsigned long           i_ino;
-        unsigned int            i_nlink;
+        /*
+         * Filesystems may only read i_nlink directly.  They shall use the
+         * following functions for modification:
+         *
+         *    (set|clear|inc|drop)_nlink
+         *    inode_(inc|dec)_link_count
+         */
+        union {
+                const unsigned int i_nlink;
+                unsigned int __i_nlink;
+        };
         dev_t                   i_rdev;
         struct timespec         i_atime;
         struct timespec         i_mtime;
@@ -1755,6 +1765,19 @@ static inline void mark_inode_dirty_sync(struct inode *inode)
 }
 
 /**
+ * set_nlink - directly set an inode's link count
+ * @inode: inode
+ * @nlink: new nlink (should be non-zero)
+ *
+ * This is a low-level filesystem helper to replace any
+ * direct filesystem manipulation of i_nlink.
+ */
+static inline void set_nlink(struct inode *inode, unsigned int nlink)
+{
+        inode->__i_nlink = nlink;
+}
+
+/**
  * inc_nlink - directly increment an inode's link count
  * @inode: inode
  *
@@ -1764,7 +1787,7 @@ static inline void mark_inode_dirty_sync(struct inode *inode)
  */
 static inline void inc_nlink(struct inode *inode)
 {
-        inode->i_nlink++;
+        inode->__i_nlink++;
 }
 
 static inline void inode_inc_link_count(struct inode *inode)
@@ -1786,7 +1809,7 @@ static inline void inode_inc_link_count(struct inode *inode)
  */
 static inline void drop_nlink(struct inode *inode)
 {
-        inode->i_nlink--;
+        inode->__i_nlink--;
 }
 
 /**
@@ -1799,7 +1822,7 @@ static inline void drop_nlink(struct inode *inode)
  */
 static inline void clear_nlink(struct inode *inode)
 {
-        inode->i_nlink = 0;
+        inode->__i_nlink = 0;
 }
 
 static inline void inode_dec_link_count(struct inode *inode)
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 409328d1cbbb..ffc02135c483 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -67,6 +67,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
 #define LOOKUP_EMPTY            0x4000
 
 extern int user_path_at(int, const char __user *, unsigned, struct path *);
+extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
 
 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)