1 files changed, 32 insertions, 9 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7a049fd2aa4c..0c4df261af7e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -768,14 +768,25 @@ 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;
-        loff_t                  i_size;
         struct timespec         i_atime;
         struct timespec         i_mtime;
         struct timespec         i_ctime;
-        unsigned int            i_blkbits;
+        spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
+        unsigned short          i_bytes;
         blkcnt_t                i_blocks;
+        loff_t                  i_size;
 
 #ifdef __NEED_I_SIZE_ORDERED
         seqcount_t              i_size_seqcount;
@@ -783,7 +794,6 @@ struct inode {
 
         /* Misc */
         unsigned long           i_state;
-        spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
         struct mutex            i_mutex;
 
         unsigned long           dirtied_when;   /* jiffies of first dirtying */
@@ -797,9 +807,10 @@ struct inode {
                 struct rcu_head         i_rcu;
         };
         atomic_t                i_count;
+        unsigned int            i_blkbits;
         u64                     i_version;
-        unsigned short          i_bytes;
         atomic_t                i_dio_count;
+        atomic_t                i_writecount;
         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
         struct file_lock        *i_flock;
         struct address_space    i_data;
@@ -823,7 +834,6 @@ struct inode {
 #ifdef CONFIG_IMA
         atomic_t                i_readcount; /* struct files open RO */
 #endif
-        atomic_t                i_writecount;
         void                    *i_private; /* fs or device private pointer */
 };
 
@@ -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)