Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus

1 files changed, 17 insertions, 3 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 44d9a6a7ec5..11dbf08651b 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -116,6 +116,7 @@
 
 #include <linux/capability.h>
 #include <linux/file.h>
+#include <linux/fdtable.h>
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -772,7 +773,7 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
 	 * give it the opportunity to lock the file.
 	 */
 	if (found)
-		cond_resched();
+		cond_resched_bkl();
 
 find_conflict:
 	for_each_lock(inode, before) {
@@ -1752,6 +1753,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 	struct file_lock *file_lock = locks_alloc_lock();
 	struct flock flock;
 	struct inode *inode;
+	struct file *f;
 	int error;
 
 	if (file_lock == NULL)
@@ -1824,7 +1826,15 @@ again:
 	 * Attempt to detect a close/fcntl race and recover by
 	 * releasing the lock that was just acquired.
 	 */
-	if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
+	/*
+	 * we need that spin_lock here - it prevents reordering between
+	 * update of inode->i_flock and check for it done in close().
+	 * rcu_read_lock() wouldn't do.
+	 */
+	spin_lock(&current->files->file_lock);
+	f = fcheck(fd);
+	spin_unlock(&current->files->file_lock);
+	if (!error && f != filp && flock.l_type != F_UNLCK) {
 		flock.l_type = F_UNLCK;
 		goto again;
 	}
@@ -1880,6 +1890,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
 	struct file_lock *file_lock = locks_alloc_lock();
 	struct flock64 flock;
 	struct inode *inode;
+	struct file *f;
 	int error;
 
 	if (file_lock == NULL)
@@ -1952,7 +1963,10 @@ again:
 	 * Attempt to detect a close/fcntl race and recover by
 	 * releasing the lock that was just acquired.
 	 */
-	if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
+	spin_lock(&current->files->file_lock);
+	f = fcheck(fd);
+	spin_unlock(&current->files->file_lock);
+	if (!error && f != filp && flock.l_type != F_UNLCK) {
 		flock.l_type = F_UNLCK;
 		goto again;
 	}