X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Flocks.c;h=3b0d05dcd7c1cc8f098205e781536cc2d1605acf;hb=8686a0e200419322654a75155e2e6f80346a1297;hp=c525aa4de234827c1e59960b7e0e280c8a37246a;hpb=778fc546f749c588aa2f6cd50215d2715c374252;p=pandora-kernel.git

diff --git a/fs/locks.c b/fs/locks.c
index c525aa4de234..3b0d05dcd7c1 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -60,7 +60,7 @@
  *
  *  Initial implementation of mandatory locks. SunOS turned out to be
  *  a rotten model, so I implemented the "obvious" semantics.
- *  See 'Documentation/mandatory.txt' for details.
+ *  See 'Documentation/filesystems/mandatory-locking.txt' for details.
  *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
  *
  *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to
@@ -1352,50 +1352,23 @@ int fcntl_getlease(struct file *filp)
 	return type;
 }
 
-/**
- *	generic_setlease	-	sets a lease on an open file
- *	@filp: file pointer
- *	@arg: type of lease to obtain
- *	@flp: input - file_lock to use, output - file_lock inserted
- *
- *	The (input) flp->fl_lmops->lm_break function is required
- *	by break_lease().
- *
- *	Called with file_lock_lock held.
- */
-int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
+int generic_add_lease(struct file *filp, long arg, struct file_lock **flp)
 {
 	struct file_lock *fl, **before, **my_before = NULL, *lease;
 	struct dentry *dentry = filp->f_path.dentry;
 	struct inode *inode = dentry->d_inode;
-	int error, rdlease_count = 0, wrlease_count = 0;
+	int error;
 
 	lease = *flp;
 
-	error = -EACCES;
-	if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE))
-		goto out;
-	error = -EINVAL;
-	if (!S_ISREG(inode->i_mode))
+	error = -EAGAIN;
+	if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
 		goto out;
-	error = security_file_lock(filp, arg);
-	if (error)
+	if ((arg == F_WRLCK)
+	    && ((dentry->d_count > 1)
+		|| (atomic_read(&inode->i_count) > 1)))
 		goto out;
 
-	time_out_leases(inode);
-
-	BUG_ON(!(*flp)->fl_lmops->lm_break);
-
-	if (arg != F_UNLCK) {
-		error = -EAGAIN;
-		if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
-			goto out;
-		if ((arg == F_WRLCK)
-		    && ((dentry->d_count > 1)
-			|| (atomic_read(&inode->i_count) > 1)))
-			goto out;
-	}
-
 	/*
 	 * At this point, we know that if there is an exclusive
 	 * lease on this file, then we hold it on this filp
@@ -1404,27 +1377,28 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 	 * then the file is not open by anyone (including us)
 	 * except for this filp.
 	 */
+	error = -EAGAIN;
 	for (before = &inode->i_flock;
 			((fl = *before) != NULL) && IS_LEASE(fl);
 			before = &fl->fl_next) {
-		if (fl->fl_file == filp)
+		if (fl->fl_file == filp) {
 			my_before = before;
-		else if (fl->fl_flags & FL_UNLOCK_PENDING)
-			/*
-			 * Someone is in the process of opening this
-			 * file for writing so we may not take an
-			 * exclusive lease on it.
-			 */
-			wrlease_count++;
-		else
-			rdlease_count++;
+			continue;
+		}
+		/*
+		 * No exclusive leases if someone else has a lease on
+		 * this file:
+		 */
+		if (arg == F_WRLCK)
+			goto out;
+		/*
+		 * Modifying our existing lease is OK, but no getting a
+		 * new lease if someone else is opening for write:
+		 */
+		if (fl->fl_flags & FL_UNLOCK_PENDING)
+			goto out;
 	}
 
-	error = -EAGAIN;
-	if ((arg == F_RDLCK && (wrlease_count > 0)) ||
-	    (arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0)))
-		goto out;
-
 	if (my_before != NULL) {
 		error = lease->fl_lmops->lm_change(my_before, arg);
 		if (!error)
@@ -1432,9 +1406,6 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 		goto out;
 	}
 
-	if (arg == F_UNLCK)
-		goto out;
-
 	error = -EINVAL;
 	if (!leases_enable)
 		goto out;
@@ -1445,6 +1416,62 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 out:
 	return error;
 }
+
+int generic_delete_lease(struct file *filp, struct file_lock **flp)
+{
+	struct file_lock *fl, **before;
+	struct dentry *dentry = filp->f_path.dentry;
+	struct inode *inode = dentry->d_inode;
+
+	for (before = &inode->i_flock;
+			((fl = *before) != NULL) && IS_LEASE(fl);
+			before = &fl->fl_next) {
+		if (fl->fl_file != filp)
+			continue;
+		return (*flp)->fl_lmops->lm_change(before, F_UNLCK);
+	}
+	return -EAGAIN;
+}
+
+/**
+ *	generic_setlease	-	sets a lease on an open file
+ *	@filp: file pointer
+ *	@arg: type of lease to obtain
+ *	@flp: input - file_lock to use, output - file_lock inserted
+ *
+ *	The (input) flp->fl_lmops->lm_break function is required
+ *	by break_lease().
+ *
+ *	Called with file_lock_lock held.
+ */
+int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
+{
+	struct dentry *dentry = filp->f_path.dentry;
+	struct inode *inode = dentry->d_inode;
+	int error;
+
+	if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE))
+		return -EACCES;
+	if (!S_ISREG(inode->i_mode))
+		return -EINVAL;
+	error = security_file_lock(filp, arg);
+	if (error)
+		return error;
+
+	time_out_leases(inode);
+
+	BUG_ON(!(*flp)->fl_lmops->lm_break);
+
+	switch (arg) {
+	case F_UNLCK:
+		return generic_delete_lease(filp, flp);
+	case F_RDLCK:
+	case F_WRLCK:
+		return generic_add_lease(filp, arg, flp);
+	default:
+		BUG();
+	}
+}
 EXPORT_SYMBOL(generic_setlease);
 
 static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease)