X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Flocks.c;h=11956b6179ff81a9924ab099896a07ba3892bc0b;hb=f2ab4461249df85b20930a7a57b54f39c5ae291a;hp=a0bc03495bd44e23bfa89deb6c492ee2a9ccfcb8;hpb=54522b6613a03807f057fd567794a31267ef85cb;p=linux-2.6

diff --git a/fs/locks.c b/fs/locks.c
index a0bc03495b..11956b6179 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1276,7 +1276,7 @@ int fcntl_getlease(struct file *filp)
  */
 static int __setlease(struct file *filp, long arg, struct file_lock **flp)
 {
-	struct file_lock *fl, **before, **my_before = NULL, *lease = *flp;
+	struct file_lock *fl, **before, **my_before = NULL, *lease;
 	struct dentry *dentry = filp->f_dentry;
 	struct inode *inode = dentry->d_inode;
 	int error, rdlease_count = 0, wrlease_count = 0;
@@ -1287,6 +1287,8 @@ static int __setlease(struct file *filp, long arg, struct file_lock **flp)
 	if (!flp || !(*flp) || !(*flp)->fl_lmops || !(*flp)->fl_lmops->fl_break)
 		goto out;
 
+	lease = *flp;
+
 	error = -EAGAIN;
 	if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
 		goto out;
@@ -1589,7 +1591,8 @@ out:
 /* Apply the lock described by l to an open file descriptor.
  * This implements both the F_SETLK and F_SETLKW commands of fcntl().
  */
-int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l)
+int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
+		struct flock __user *l)
 {
 	struct file_lock *file_lock = locks_alloc_lock();
 	struct flock flock;
@@ -1618,6 +1621,7 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l)
 		goto out;
 	}
 
+again:
 	error = flock_to_posix_lock(filp, file_lock, &flock);
 	if (error)
 		goto out;
@@ -1646,25 +1650,33 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l)
 	if (error)
 		goto out;
 
-	if (filp->f_op && filp->f_op->lock != NULL) {
+	if (filp->f_op && filp->f_op->lock != NULL)
 		error = filp->f_op->lock(filp, cmd, file_lock);
-		goto out;
-	}
+	else {
+		for (;;) {
+			error = __posix_lock_file(inode, file_lock);
+			if ((error != -EAGAIN) || (cmd == F_SETLK))
+				break;
+			error = wait_event_interruptible(file_lock->fl_wait,
+					!file_lock->fl_next);
+			if (!error)
+				continue;
 
-	for (;;) {
-		error = __posix_lock_file(inode, file_lock);
-		if ((error != -EAGAIN) || (cmd == F_SETLK))
+			locks_delete_block(file_lock);
 			break;
-		error = wait_event_interruptible(file_lock->fl_wait,
-				!file_lock->fl_next);
-		if (!error)
-			continue;
+		}
+	}
 
-		locks_delete_block(file_lock);
-		break;
+	/*
+	 * 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) {
+		flock.l_type = F_UNLCK;
+		goto again;
 	}
 
- out:
+out:
 	locks_free_lock(file_lock);
 	return error;
 }
@@ -1722,7 +1734,8 @@ out:
 /* Apply the lock described by l to an open file descriptor.
  * This implements both the F_SETLK and F_SETLKW commands of fcntl().
  */
-int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
+int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
+		struct flock64 __user *l)
 {
 	struct file_lock *file_lock = locks_alloc_lock();
 	struct flock64 flock;
@@ -1751,6 +1764,7 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
 		goto out;
 	}
 
+again:
 	error = flock64_to_posix_lock(filp, file_lock, &flock);
 	if (error)
 		goto out;
@@ -1779,22 +1793,30 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
 	if (error)
 		goto out;
 
-	if (filp->f_op && filp->f_op->lock != NULL) {
+	if (filp->f_op && filp->f_op->lock != NULL)
 		error = filp->f_op->lock(filp, cmd, file_lock);
-		goto out;
-	}
+	else {
+		for (;;) {
+			error = __posix_lock_file(inode, file_lock);
+			if ((error != -EAGAIN) || (cmd == F_SETLK64))
+				break;
+			error = wait_event_interruptible(file_lock->fl_wait,
+					!file_lock->fl_next);
+			if (!error)
+				continue;
 
-	for (;;) {
-		error = __posix_lock_file(inode, file_lock);
-		if ((error != -EAGAIN) || (cmd == F_SETLK64))
+			locks_delete_block(file_lock);
 			break;
-		error = wait_event_interruptible(file_lock->fl_wait,
-				!file_lock->fl_next);
-		if (!error)
-			continue;
+		}
+	}
 
-		locks_delete_block(file_lock);
-		break;
+	/*
+	 * 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) {
+		flock.l_type = F_UNLCK;
+		goto again;
 	}
 
 out:
@@ -1886,12 +1908,7 @@ void locks_remove_flock(struct file *filp)
 
 	while ((fl = *before) != NULL) {
 		if (fl->fl_file == filp) {
-			/*
-			 * We might have a POSIX lock that was created at the same time
-			 * the filp was closed for the last time. Just remove that too,
-			 * regardless of ownership, since nobody can own it.
-			 */
-			if (IS_FLOCK(fl) || IS_POSIX(fl)) {
+			if (IS_FLOCK(fl)) {
 				locks_delete_lock(before);
 				continue;
 			}