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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 | /* -*- 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> #define MLOG_MASK_PREFIX ML_INODE #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. */ flock_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 = flock_lock_file_wait(file, fl); 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 = flock_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 flock_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); } |