1 files changed, 26 insertions, 15 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 56f996e98bbc..4d9e71d43e7e 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -142,7 +142,7 @@ int lease_break_time = 45;
 static LIST_HEAD(file_lock_list);
 static LIST_HEAD(blocked_list);
 
-static kmem_cache_t *filelock_cache;
+static kmem_cache_t *filelock_cache __read_mostly;
 
 /* Allocate an empty lock structure. */
 static struct file_lock *locks_alloc_lock(void)
@@ -533,12 +533,7 @@ static void locks_delete_block(struct file_lock *waiter)
 static void locks_insert_block(struct file_lock *blocker, 
                                struct file_lock *waiter)
 {
-        if (!list_empty(&waiter->fl_block)) {
-                printk(KERN_ERR "locks_insert_block: removing duplicated lock "
-                        "(pid=%d %Ld-%Ld type=%d)\n", waiter->fl_pid,
-                        waiter->fl_start, waiter->fl_end, waiter->fl_type);
-                __locks_delete_block(waiter);
-        }
+        BUG_ON(!list_empty(&waiter->fl_block));
         list_add_tail(&waiter->fl_block, &blocker->fl_block);
         waiter->fl_next = blocker;
         if (IS_POSIX(blocker))
@@ -797,9 +792,7 @@ out:
         return error;
 }
 
-EXPORT_SYMBOL(posix_lock_file);
-
-static int __posix_lock_file(struct inode *inode, struct file_lock *request)
+static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
 {
         struct file_lock *fl;
         struct file_lock *new_fl, *new_fl2;
@@ -823,6 +816,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request)
                                 continue;
                         if (!posix_locks_conflict(request, fl))
                                 continue;
+                        if (conflock)
+                                locks_copy_lock(conflock, fl);
                         error = -EAGAIN;
                         if (!(request->fl_flags & FL_SLEEP))
                                 goto out;
@@ -992,8 +987,24 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request)
  */
 int posix_lock_file(struct file *filp, struct file_lock *fl)
 {
-        return __posix_lock_file(filp->f_dentry->d_inode, fl);
+        return __posix_lock_file_conf(filp->f_dentry->d_inode, fl, NULL);
+}
+EXPORT_SYMBOL(posix_lock_file);
+
+/**
+ * posix_lock_file_conf - Apply a POSIX-style lock to a file
+ * @filp: The file to apply the lock to
+ * @fl: The lock to be applied
+ * @conflock: Place to return a copy of the conflicting lock, if found.
+ *
+ * Except for the conflock parameter, acts just like posix_lock_file.
+ */
+int posix_lock_file_conf(struct file *filp, struct file_lock *fl,
+                        struct file_lock *conflock)
+{
+        return __posix_lock_file_conf(filp->f_dentry->d_inode, fl, conflock);
 }
+EXPORT_SYMBOL(posix_lock_file_conf);
 
 /**
  * posix_lock_file_wait - Apply a POSIX-style lock to a file
@@ -1009,7 +1020,7 @@ int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
         int error;
         might_sleep ();
         for (;;) {
-                error = __posix_lock_file(filp->f_dentry->d_inode, fl);
+                error = posix_lock_file(filp, fl);
                 if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
                         break;
                 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
@@ -1081,7 +1092,7 @@ int locks_mandatory_area(int read_write, struct inode *inode,
         fl.fl_end = offset + count - 1;
 
         for (;;) {
-                error = __posix_lock_file(inode, &fl);
+                error = __posix_lock_file_conf(inode, &fl, NULL);
                 if (error != -EAGAIN)
                         break;
                 if (!(fl.fl_flags & FL_SLEEP))
@@ -1694,7 +1705,7 @@ again:
                 error = filp->f_op->lock(filp, cmd, file_lock);
         else {
                 for (;;) {
-                        error = __posix_lock_file(inode, file_lock);
+                        error = posix_lock_file(filp, file_lock);
                         if ((error != -EAGAIN) || (cmd == F_SETLK))
                                 break;
                         error = wait_event_interruptible(file_lock->fl_wait,
@@ -1837,7 +1848,7 @@ again:
                 error = filp->f_op->lock(filp, cmd, file_lock);
         else {
                 for (;;) {
-                        error = __posix_lock_file(inode, file_lock);
+                        error = posix_lock_file(filp, file_lock);
                         if ((error != -EAGAIN) || (cmd == F_SETLK64))
                                 break;
                         error = wait_event_interruptible(file_lock->fl_wait,