| /* -*- mode: c; c-basic-offset: 8; -*- |
| * vim: noexpandtab sw=8 ts=8 sts=0: |
| * |
| * locks.c |
| * |
| * Userspace file locking support |
| * |
| * Copyright (C) 2007 Oracle. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/fcntl.h> |
| |
| #include <cluster/masklog.h> |
| |
| #include "ocfs2.h" |
| |
| #include "dlmglue.h" |
| #include "file.h" |
| #include "inode.h" |
| #include "locks.h" |
| |
| static int ocfs2_do_flock(struct file *file, struct inode *inode, |
| int cmd, struct file_lock *fl) |
| { |
| int ret = 0, level = 0, trylock = 0; |
| struct ocfs2_file_private *fp = file->private_data; |
| struct ocfs2_lock_res *lockres = &fp->fp_flock; |
| |
| if (fl->fl_type == F_WRLCK) |
| level = 1; |
| if (!IS_SETLKW(cmd)) |
| trylock = 1; |
| |
| mutex_lock(&fp->fp_mutex); |
| |
| if (lockres->l_flags & OCFS2_LOCK_ATTACHED && |
| lockres->l_level > LKM_NLMODE) { |
| int old_level = 0; |
| |
| if (lockres->l_level == LKM_EXMODE) |
| old_level = 1; |
| |
| if (level == old_level) |
| goto out; |
| |
| /* |
| * Converting an existing lock is not guaranteed to be |
| * atomic, so we can get away with simply unlocking |
| * here and allowing the lock code to try at the new |
| * level. |
| */ |
| |
| locks_lock_file_wait(file, |
| &(struct file_lock){.fl_type = F_UNLCK}); |
| |
| ocfs2_file_unlock(file); |
| } |
| |
| ret = ocfs2_file_lock(file, level, trylock); |
| if (ret) { |
| if (ret == -EAGAIN && trylock) |
| ret = -EWOULDBLOCK; |
| else |
| mlog_errno(ret); |
| goto out; |
| } |
| |
| ret = locks_lock_file_wait(file, fl); |
| if (ret) |
| ocfs2_file_unlock(file); |
| |
| out: |
| mutex_unlock(&fp->fp_mutex); |
| |
| return ret; |
| } |
| |
| static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) |
| { |
| int ret; |
| struct ocfs2_file_private *fp = file->private_data; |
| |
| mutex_lock(&fp->fp_mutex); |
| ocfs2_file_unlock(file); |
| ret = locks_lock_file_wait(file, fl); |
| mutex_unlock(&fp->fp_mutex); |
| |
| return ret; |
| } |
| |
| /* |
| * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). |
| */ |
| int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) |
| { |
| struct inode *inode = file->f_mapping->host; |
| struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); |
| |
| if (!(fl->fl_flags & FL_FLOCK)) |
| return -ENOLCK; |
| if (__mandatory_lock(inode)) |
| return -ENOLCK; |
| |
| if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || |
| ocfs2_mount_local(osb)) |
| return locks_lock_file_wait(file, fl); |
| |
| if (fl->fl_type == F_UNLCK) |
| return ocfs2_do_funlock(file, cmd, fl); |
| else |
| return ocfs2_do_flock(file, inode, cmd, fl); |
| } |
| |
| int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) |
| { |
| struct inode *inode = file->f_mapping->host; |
| struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); |
| |
| if (!(fl->fl_flags & FL_POSIX)) |
| return -ENOLCK; |
| if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) |
| return -ENOLCK; |
| |
| return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); |
| } |