X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Flocks.c;h=0ac6b92cb0b6365a19a7d4c337362a97b320a0a6;hb=1df5a8d004f64b1aa3fb93e0556886ba00ebc979;hp=da1d0ddb4abdd8040dbbbe1681328b204e63a9c2;hpb=288b2fd8251cb0bcb14b8a93755ef9c78de70e0f;p=linux-2.6

diff --git a/fs/locks.c b/fs/locks.c
index da1d0ddb4a..0ac6b92cb0 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>
@@ -224,7 +225,7 @@ static void locks_copy_private(struct file_lock *new, struct file_lock *fl)
 /*
  * Initialize a new lock from an existing file_lock structure.
  */
-static void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
+void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
 {
 	new->fl_owner = fl->fl_owner;
 	new->fl_pid = fl->fl_pid;
@@ -236,6 +237,7 @@ static void __locks_copy_lock(struct file_lock *new, const struct file_lock *fl)
 	new->fl_ops = NULL;
 	new->fl_lmops = NULL;
 }
+EXPORT_SYMBOL(__locks_copy_lock);
 
 void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 {
@@ -833,7 +835,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 			if (!posix_locks_conflict(request, fl))
 				continue;
 			if (conflock)
-				locks_copy_lock(conflock, fl);
+				__locks_copy_lock(conflock, fl);
 			error = -EAGAIN;
 			if (!(request->fl_flags & FL_SLEEP))
 				goto out;
@@ -1368,6 +1370,11 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 	lease = *flp;
 
 	if (arg != F_UNLCK) {
+		error = -ENOMEM;
+		new_fl = locks_alloc_lock();
+		if (new_fl == NULL)
+			goto out;
+
 		error = -EAGAIN;
 		if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
 			goto out;
@@ -1375,11 +1382,6 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 		    && ((atomic_read(&dentry->d_count) > 1)
 			|| (atomic_read(&inode->i_count) > 1)))
 			goto out;
-
-		error = -ENOMEM;
-		new_fl = locks_alloc_lock();
-		if (new_fl == NULL)
-			goto out;
 	}
 
 	/*
@@ -1493,8 +1495,7 @@ EXPORT_SYMBOL_GPL(vfs_setlease);
 int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
 {
 	struct file_lock fl, *flp = &fl;
-	struct dentry *dentry = filp->f_path.dentry;
-	struct inode *inode = dentry->d_inode;
+	struct inode *inode = filp->f_path.dentry->d_inode;
 	int error;
 
 	locks_init_lock(&fl);
@@ -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;
 	}