3 files changed, 57 insertions, 1 deletions

diff --git a/fs/inode.c b/fs/inode.c
index aa149e7262ac..f30872ade6d7 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -194,7 +194,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 #ifdef CONFIG_FSNOTIFY
         inode->i_fsnotify_mask = 0;
 #endif
-
+        inode->i_flctx = NULL;
         this_cpu_inc(nr_inodes);
 
         return 0;
@@ -237,6 +237,7 @@ void __destroy_inode(struct inode *inode)
         BUG_ON(inode_has_buffers(inode));
         security_inode_free(inode);
         fsnotify_inode_delete(inode);
+        locks_free_lock_context(inode->i_flctx);
         if (!inode->i_nlink) {
                 WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
                 atomic_long_dec(&inode->i_sb->s_remove_count);
diff --git a/fs/locks.c b/fs/locks.c
index ae1e7cf721d6..526d5fca67c8 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -202,8 +202,49 @@ static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
  */
 static DEFINE_SPINLOCK(blocked_lock_lock);
 
+static struct kmem_cache *flctx_cache __read_mostly;
 static struct kmem_cache *filelock_cache __read_mostly;
 
+static struct file_lock_context *
+locks_get_lock_context(struct inode *inode)
+{
+        struct file_lock_context *new;
+
+        if (likely(inode->i_flctx))
+                goto out;
+
+        new = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
+        if (!new)
+                goto out;
+
+        INIT_LIST_HEAD(&new->flc_flock);
+
+        /*
+         * Assign the pointer if it's not already assigned. If it is, then
+         * free the context we just allocated.
+         */
+        spin_lock(&inode->i_lock);
+        if (likely(!inode->i_flctx)) {
+                inode->i_flctx = new;
+                new = NULL;
+        }
+        spin_unlock(&inode->i_lock);
+
+        if (new)
+                kmem_cache_free(flctx_cache, new);
+out:
+        return inode->i_flctx;
+}
+
+void
+locks_free_lock_context(struct file_lock_context *ctx)
+{
+        if (ctx) {
+                WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
+                kmem_cache_free(flctx_cache, ctx);
+        }
+}
+
 static void locks_init_lock_heads(struct file_lock *fl)
 {
         INIT_HLIST_NODE(&fl->fl_link);
@@ -2636,6 +2677,9 @@ static int __init filelock_init(void)
 {
         int i;
 
+        flctx_cache = kmem_cache_create("file_lock_ctx",
+                        sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
+
         filelock_cache = kmem_cache_create("file_lock_cache",
                         sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cd6818115162..dec0d38b05de 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -626,6 +626,7 @@ struct inode {
 #endif
         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
         struct file_lock        *i_flock;
+        struct file_lock_context        *i_flctx;
         struct address_space    i_data;
         struct list_head        i_devices;
         union {
@@ -965,6 +966,10 @@ struct file_lock {
         } fl_u;
 };
 
+struct file_lock_context {
+        struct list_head        flc_flock;
+};
+
 /* The following constant reflects the upper bound of the file/locking space */
 #ifndef OFFSET_MAX
 #define INT_LIMIT(x)    (~((x)1 << (sizeof(x)*8 - 1)))
@@ -991,6 +996,7 @@ extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
 extern int fcntl_getlease(struct file *filp);
 
 /* fs/locks.c */
+void locks_free_lock_context(struct file_lock_context *ctx);
 void locks_free_lock(struct file_lock *fl);
 extern void locks_init_lock(struct file_lock *);
 extern struct file_lock * locks_alloc_lock(void);
@@ -1048,6 +1054,11 @@ static inline int fcntl_getlease(struct file *filp)
         return F_UNLCK;
 }
 
+static inline void
+locks_free_lock_context(struct file_lock_context *ctx)
+{
+}
+
 static inline void locks_init_lock(struct file_lock *fl)
 {
         return;