X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=fs%2Flocks.c;h=efad798824dc19913b7aace09dbee47b8c6ca6a7;hb=99532559dc7a8e686b2cef14c780a7ad5dbd4a31;hp=56f996e98bbcd03459480ce9ea505e2663b46129;hpb=3661f00e2097676847deb01add1a0918044bd816;p=linux-2.6-omap-h63xx.git

diff --git a/fs/locks.c b/fs/locks.c
index 56f996e98bb..efad798824d 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)
@@ -168,18 +168,9 @@ static void locks_release_private(struct file_lock *fl)
 /* Free a lock which is not in use. */
 static void locks_free_lock(struct file_lock *fl)
 {
-	if (fl == NULL) {
-		BUG();
-		return;
-	}
-	if (waitqueue_active(&fl->fl_wait))
-		panic("Attempting to free lock with active wait queue");
-
-	if (!list_empty(&fl->fl_block))
-		panic("Attempting to free lock with active block list");
-
-	if (!list_empty(&fl->fl_link))
-		panic("Attempting to free lock on active lock list");
+	BUG_ON(waitqueue_active(&fl->fl_wait));
+	BUG_ON(!list_empty(&fl->fl_block));
+	BUG_ON(!list_empty(&fl->fl_link));
 
 	locks_release_private(fl);
 	kmem_cache_free(filelock_cache, fl);
@@ -533,12 +524,7 @@ 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))
@@ -740,8 +726,9 @@ EXPORT_SYMBOL(posix_locks_deadlock);
  * at the head of the list, but that's secret knowledge known only to
  * flock_lock_file and posix_lock_file.
  */
-static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
+static int flock_lock_file(struct file *filp, struct file_lock *request)
 {
+	struct file_lock *new_fl = NULL;
 	struct file_lock **before;
 	struct inode * inode = filp->f_dentry->d_inode;
 	int error = 0;
@@ -756,17 +743,19 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
 			continue;
 		if (filp != fl->fl_file)
 			continue;
-		if (new_fl->fl_type == fl->fl_type)
+		if (request->fl_type == fl->fl_type)
 			goto out;
 		found = 1;
 		locks_delete_lock(before);
 		break;
 	}
-	unlock_kernel();
 
-	if (new_fl->fl_type == F_UNLCK)
-		return 0;
+	if (request->fl_type == F_UNLCK)
+		goto out;
 
+	new_fl = locks_alloc_lock();
+	if (new_fl == NULL)
+		goto out;
 	/*
 	 * If a higher-priority process was blocked on the old file lock,
 	 * give it the opportunity to lock the file.
@@ -774,32 +763,31 @@ static int flock_lock_file(struct file *filp, struct file_lock *new_fl)
 	if (found)
 		cond_resched();
 
-	lock_kernel();
 	for_each_lock(inode, before) {
 		struct file_lock *fl = *before;
 		if (IS_POSIX(fl))
 			break;
 		if (IS_LEASE(fl))
 			continue;
-		if (!flock_locks_conflict(new_fl, fl))
+		if (!flock_locks_conflict(request, fl))
 			continue;
 		error = -EAGAIN;
-		if (new_fl->fl_flags & FL_SLEEP) {
-			locks_insert_block(fl, new_fl);
-		}
+		if (request->fl_flags & FL_SLEEP)
+			locks_insert_block(fl, request);
 		goto out;
 	}
+	locks_copy_lock(new_fl, request);
 	locks_insert_lock(&inode->i_flock, new_fl);
-	error = 0;
+	new_fl = NULL;
 
 out:
 	unlock_kernel();
+	if (new_fl)
+		locks_free_lock(new_fl);
 	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 +811,8 @@ 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 +982,24 @@ 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 +1015,7 @@ 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 +1087,7 @@ 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))
@@ -1558,9 +1564,7 @@ asmlinkage long sys_flock(unsigned int fd, unsigned int cmd)
 		error = flock_lock_file_wait(filp, lock);
 
  out_free:
-	if (list_empty(&lock->fl_link)) {
-		locks_free_lock(lock);
-	}
+	locks_free_lock(lock);
 
  out_putf:
 	fput(filp);
@@ -1694,7 +1698,7 @@ 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 +1841,7 @@ 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,
@@ -2226,7 +2230,12 @@ void steal_locks(fl_owner_t from)
 
 	lock_kernel();
 	j = 0;
-	rcu_read_lock();
+
+	/*
+	 * We are not taking a ref to the file structures, so
+	 * we need to acquire ->file_lock.
+	 */
+	spin_lock(&files->file_lock);
 	fdt = files_fdtable(files);
 	for (;;) {
 		unsigned long set;
@@ -2244,7 +2253,7 @@ void steal_locks(fl_owner_t from)
 			set >>= 1;
 		}
 	}
-	rcu_read_unlock();
+	spin_unlock(&files->file_lock);
 	unlock_kernel();
 }
 EXPORT_SYMBOL(steal_locks);