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xianfeng |
/* AFS file locking support
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/smp_lock.h>
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#include "internal.h"
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#define AFS_LOCK_GRANTED 0
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#define AFS_LOCK_PENDING 1
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static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);
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static void afs_fl_release_private(struct file_lock *fl);
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static struct workqueue_struct *afs_lock_manager;
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static DEFINE_MUTEX(afs_lock_manager_mutex);
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static struct file_lock_operations afs_lock_ops = {
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.fl_copy_lock = afs_fl_copy_lock,
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.fl_release_private = afs_fl_release_private,
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};
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/*
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* initialise the lock manager thread if it isn't already running
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*/
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static int afs_init_lock_manager(void)
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{
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int ret;
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ret = 0;
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37 |
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if (!afs_lock_manager) {
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38 |
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mutex_lock(&afs_lock_manager_mutex);
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if (!afs_lock_manager) {
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afs_lock_manager =
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create_singlethread_workqueue("kafs_lockd");
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if (!afs_lock_manager)
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ret = -ENOMEM;
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44 |
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}
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mutex_unlock(&afs_lock_manager_mutex);
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}
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return ret;
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}
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/*
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* destroy the lock manager thread if it's running
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*/
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void __exit afs_kill_lock_manager(void)
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54 |
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{
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if (afs_lock_manager)
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destroy_workqueue(afs_lock_manager);
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}
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/*
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* if the callback is broken on this vnode, then the lock may now be available
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*/
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void afs_lock_may_be_available(struct afs_vnode *vnode)
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{
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_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
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queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
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}
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/*
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* the lock will time out in 5 minutes unless we extend it, so schedule
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* extension in a bit less than that time
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*/
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static void afs_schedule_lock_extension(struct afs_vnode *vnode)
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{
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queue_delayed_work(afs_lock_manager, &vnode->lock_work,
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AFS_LOCKWAIT * HZ / 2);
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}
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/*
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* grant one or more locks (readlocks are allowed to jump the queue if the
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* first lock in the queue is itself a readlock)
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* - the caller must hold the vnode lock
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*/
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static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl)
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{
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struct file_lock *p, *_p;
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87 |
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list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
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if (fl->fl_type == F_RDLCK) {
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list_for_each_entry_safe(p, _p, &vnode->pending_locks,
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fl_u.afs.link) {
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if (p->fl_type == F_RDLCK) {
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p->fl_u.afs.state = AFS_LOCK_GRANTED;
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list_move_tail(&p->fl_u.afs.link,
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&vnode->granted_locks);
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wake_up(&p->fl_wait);
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}
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}
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}
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}
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/*
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* do work for a lock, including:
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* - probing for a lock we're waiting on but didn't get immediately
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* - extending a lock that's close to timing out
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*/
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void afs_lock_work(struct work_struct *work)
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108 |
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{
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109 |
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struct afs_vnode *vnode =
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container_of(work, struct afs_vnode, lock_work.work);
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111 |
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struct file_lock *fl;
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112 |
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afs_lock_type_t type;
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113 |
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struct key *key;
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114 |
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int ret;
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115 |
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_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
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117 |
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spin_lock(&vnode->lock);
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119 |
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120 |
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if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) {
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_debug("unlock");
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spin_unlock(&vnode->lock);
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123 |
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/* attempt to release the server lock; if it fails, we just
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125 |
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* wait 5 minutes and it'll time out anyway */
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126 |
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ret = afs_vnode_release_lock(vnode, vnode->unlock_key);
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127 |
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if (ret < 0)
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128 |
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printk(KERN_WARNING "AFS:"
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" Failed to release lock on {%x:%x} error %d\n",
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vnode->fid.vid, vnode->fid.vnode, ret);
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131 |
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132 |
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spin_lock(&vnode->lock);
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133 |
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key_put(vnode->unlock_key);
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134 |
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vnode->unlock_key = NULL;
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135 |
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clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags);
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136 |
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}
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137 |
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138 |
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/* if we've got a lock, then it must be time to extend that lock as AFS
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139 |
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* locks time out after 5 minutes */
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140 |
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if (!list_empty(&vnode->granted_locks)) {
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141 |
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_debug("extend");
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142 |
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143 |
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if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
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144 |
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BUG();
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145 |
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fl = list_entry(vnode->granted_locks.next,
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146 |
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struct file_lock, fl_u.afs.link);
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147 |
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key = key_get(fl->fl_file->private_data);
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148 |
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spin_unlock(&vnode->lock);
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149 |
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150 |
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ret = afs_vnode_extend_lock(vnode, key);
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clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
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152 |
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key_put(key);
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153 |
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switch (ret) {
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154 |
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case 0:
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155 |
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afs_schedule_lock_extension(vnode);
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156 |
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break;
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157 |
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default:
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158 |
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/* ummm... we failed to extend the lock - retry
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159 |
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* extension shortly */
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160 |
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printk(KERN_WARNING "AFS:"
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161 |
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" Failed to extend lock on {%x:%x} error %d\n",
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vnode->fid.vid, vnode->fid.vnode, ret);
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queue_delayed_work(afs_lock_manager, &vnode->lock_work,
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HZ * 10);
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break;
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166 |
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}
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_leave(" [extend]");
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168 |
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return;
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169 |
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}
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170 |
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171 |
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/* if we don't have a granted lock, then we must've been called back by
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172 |
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* the server, and so if might be possible to get a lock we're
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173 |
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* currently waiting for */
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174 |
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if (!list_empty(&vnode->pending_locks)) {
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175 |
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_debug("get");
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177 |
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if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
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178 |
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BUG();
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179 |
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fl = list_entry(vnode->pending_locks.next,
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180 |
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struct file_lock, fl_u.afs.link);
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181 |
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key = key_get(fl->fl_file->private_data);
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182 |
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type = (fl->fl_type == F_RDLCK) ?
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183 |
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AFS_LOCK_READ : AFS_LOCK_WRITE;
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184 |
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spin_unlock(&vnode->lock);
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185 |
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186 |
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ret = afs_vnode_set_lock(vnode, key, type);
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187 |
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clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
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188 |
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switch (ret) {
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189 |
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case -EWOULDBLOCK:
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190 |
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_debug("blocked");
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191 |
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break;
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192 |
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case 0:
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193 |
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_debug("acquired");
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194 |
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if (type == AFS_LOCK_READ)
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195 |
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set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
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196 |
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else
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197 |
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set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
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198 |
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ret = AFS_LOCK_GRANTED;
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199 |
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default:
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200 |
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spin_lock(&vnode->lock);
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201 |
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/* the pending lock may have been withdrawn due to a
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202 |
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* signal */
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203 |
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if (list_entry(vnode->pending_locks.next,
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204 |
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struct file_lock, fl_u.afs.link) == fl) {
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205 |
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fl->fl_u.afs.state = ret;
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206 |
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if (ret == AFS_LOCK_GRANTED)
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207 |
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afs_grant_locks(vnode, fl);
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208 |
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else
|
209 |
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list_del_init(&fl->fl_u.afs.link);
|
210 |
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wake_up(&fl->fl_wait);
|
211 |
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spin_unlock(&vnode->lock);
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212 |
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} else {
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213 |
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_debug("withdrawn");
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214 |
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clear_bit(AFS_VNODE_READLOCKED, &vnode->flags);
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215 |
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clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
|
216 |
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spin_unlock(&vnode->lock);
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217 |
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afs_vnode_release_lock(vnode, key);
|
218 |
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if (!list_empty(&vnode->pending_locks))
|
219 |
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afs_lock_may_be_available(vnode);
|
220 |
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}
|
221 |
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break;
|
222 |
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}
|
223 |
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key_put(key);
|
224 |
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_leave(" [pend]");
|
225 |
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return;
|
226 |
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}
|
227 |
|
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|
228 |
|
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/* looks like the lock request was withdrawn on a signal */
|
229 |
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spin_unlock(&vnode->lock);
|
230 |
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_leave(" [no locks]");
|
231 |
|
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}
|
232 |
|
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|
233 |
|
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/*
|
234 |
|
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* pass responsibility for the unlocking of a vnode on the server to the
|
235 |
|
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* manager thread, lest a pending signal in the calling thread interrupt
|
236 |
|
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* AF_RXRPC
|
237 |
|
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* - the caller must hold the vnode lock
|
238 |
|
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*/
|
239 |
|
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static void afs_defer_unlock(struct afs_vnode *vnode, struct key *key)
|
240 |
|
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{
|
241 |
|
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cancel_delayed_work(&vnode->lock_work);
|
242 |
|
|
if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) &&
|
243 |
|
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!test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags))
|
244 |
|
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BUG();
|
245 |
|
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if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags))
|
246 |
|
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BUG();
|
247 |
|
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vnode->unlock_key = key_get(key);
|
248 |
|
|
afs_lock_may_be_available(vnode);
|
249 |
|
|
}
|
250 |
|
|
|
251 |
|
|
/*
|
252 |
|
|
* request a lock on a file on the server
|
253 |
|
|
*/
|
254 |
|
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static int afs_do_setlk(struct file *file, struct file_lock *fl)
|
255 |
|
|
{
|
256 |
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
|
257 |
|
|
afs_lock_type_t type;
|
258 |
|
|
struct key *key = file->private_data;
|
259 |
|
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int ret;
|
260 |
|
|
|
261 |
|
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_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
|
262 |
|
|
|
263 |
|
|
/* only whole-file locks are supported */
|
264 |
|
|
if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
|
265 |
|
|
return -EINVAL;
|
266 |
|
|
|
267 |
|
|
ret = afs_init_lock_manager();
|
268 |
|
|
if (ret < 0)
|
269 |
|
|
return ret;
|
270 |
|
|
|
271 |
|
|
fl->fl_ops = &afs_lock_ops;
|
272 |
|
|
INIT_LIST_HEAD(&fl->fl_u.afs.link);
|
273 |
|
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
274 |
|
|
|
275 |
|
|
type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
|
276 |
|
|
|
277 |
|
|
lock_kernel();
|
278 |
|
|
|
279 |
|
|
/* make sure we've got a callback on this file and that our view of the
|
280 |
|
|
* data version is up to date */
|
281 |
|
|
ret = afs_vnode_fetch_status(vnode, NULL, key);
|
282 |
|
|
if (ret < 0)
|
283 |
|
|
goto error;
|
284 |
|
|
|
285 |
|
|
if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) {
|
286 |
|
|
ret = -EAGAIN;
|
287 |
|
|
goto error;
|
288 |
|
|
}
|
289 |
|
|
|
290 |
|
|
spin_lock(&vnode->lock);
|
291 |
|
|
|
292 |
|
|
/* if we've already got a readlock on the server then we can instantly
|
293 |
|
|
* grant another readlock, irrespective of whether there are any
|
294 |
|
|
* pending writelocks */
|
295 |
|
|
if (type == AFS_LOCK_READ &&
|
296 |
|
|
vnode->flags & (1 << AFS_VNODE_READLOCKED)) {
|
297 |
|
|
_debug("instant readlock");
|
298 |
|
|
ASSERTCMP(vnode->flags &
|
299 |
|
|
((1 << AFS_VNODE_LOCKING) |
|
300 |
|
|
(1 << AFS_VNODE_WRITELOCKED)), ==, 0);
|
301 |
|
|
ASSERT(!list_empty(&vnode->granted_locks));
|
302 |
|
|
goto sharing_existing_lock;
|
303 |
|
|
}
|
304 |
|
|
|
305 |
|
|
/* if there's no-one else with a lock on this vnode, then we need to
|
306 |
|
|
* ask the server for a lock */
|
307 |
|
|
if (list_empty(&vnode->pending_locks) &&
|
308 |
|
|
list_empty(&vnode->granted_locks)) {
|
309 |
|
|
_debug("not locked");
|
310 |
|
|
ASSERTCMP(vnode->flags &
|
311 |
|
|
((1 << AFS_VNODE_LOCKING) |
|
312 |
|
|
(1 << AFS_VNODE_READLOCKED) |
|
313 |
|
|
(1 << AFS_VNODE_WRITELOCKED)), ==, 0);
|
314 |
|
|
list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
|
315 |
|
|
set_bit(AFS_VNODE_LOCKING, &vnode->flags);
|
316 |
|
|
spin_unlock(&vnode->lock);
|
317 |
|
|
|
318 |
|
|
ret = afs_vnode_set_lock(vnode, key, type);
|
319 |
|
|
clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
|
320 |
|
|
switch (ret) {
|
321 |
|
|
case 0:
|
322 |
|
|
_debug("acquired");
|
323 |
|
|
goto acquired_server_lock;
|
324 |
|
|
case -EWOULDBLOCK:
|
325 |
|
|
_debug("would block");
|
326 |
|
|
spin_lock(&vnode->lock);
|
327 |
|
|
ASSERT(list_empty(&vnode->granted_locks));
|
328 |
|
|
ASSERTCMP(vnode->pending_locks.next, ==,
|
329 |
|
|
&fl->fl_u.afs.link);
|
330 |
|
|
goto wait;
|
331 |
|
|
default:
|
332 |
|
|
spin_lock(&vnode->lock);
|
333 |
|
|
list_del_init(&fl->fl_u.afs.link);
|
334 |
|
|
spin_unlock(&vnode->lock);
|
335 |
|
|
goto error;
|
336 |
|
|
}
|
337 |
|
|
}
|
338 |
|
|
|
339 |
|
|
/* otherwise, we need to wait for a local lock to become available */
|
340 |
|
|
_debug("wait local");
|
341 |
|
|
list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
|
342 |
|
|
wait:
|
343 |
|
|
if (!(fl->fl_flags & FL_SLEEP)) {
|
344 |
|
|
_debug("noblock");
|
345 |
|
|
ret = -EAGAIN;
|
346 |
|
|
goto abort_attempt;
|
347 |
|
|
}
|
348 |
|
|
spin_unlock(&vnode->lock);
|
349 |
|
|
|
350 |
|
|
/* now we need to sleep and wait for the lock manager thread to get the
|
351 |
|
|
* lock from the server */
|
352 |
|
|
_debug("sleep");
|
353 |
|
|
ret = wait_event_interruptible(fl->fl_wait,
|
354 |
|
|
fl->fl_u.afs.state <= AFS_LOCK_GRANTED);
|
355 |
|
|
if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
|
356 |
|
|
ret = fl->fl_u.afs.state;
|
357 |
|
|
if (ret < 0)
|
358 |
|
|
goto error;
|
359 |
|
|
spin_lock(&vnode->lock);
|
360 |
|
|
goto given_lock;
|
361 |
|
|
}
|
362 |
|
|
|
363 |
|
|
/* we were interrupted, but someone may still be in the throes of
|
364 |
|
|
* giving us the lock */
|
365 |
|
|
_debug("intr");
|
366 |
|
|
ASSERTCMP(ret, ==, -ERESTARTSYS);
|
367 |
|
|
|
368 |
|
|
spin_lock(&vnode->lock);
|
369 |
|
|
if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
|
370 |
|
|
ret = fl->fl_u.afs.state;
|
371 |
|
|
if (ret < 0) {
|
372 |
|
|
spin_unlock(&vnode->lock);
|
373 |
|
|
goto error;
|
374 |
|
|
}
|
375 |
|
|
goto given_lock;
|
376 |
|
|
}
|
377 |
|
|
|
378 |
|
|
abort_attempt:
|
379 |
|
|
/* we aren't going to get the lock, either because we're unwilling to
|
380 |
|
|
* wait, or because some signal happened */
|
381 |
|
|
_debug("abort");
|
382 |
|
|
if (list_empty(&vnode->granted_locks) &&
|
383 |
|
|
vnode->pending_locks.next == &fl->fl_u.afs.link) {
|
384 |
|
|
if (vnode->pending_locks.prev != &fl->fl_u.afs.link) {
|
385 |
|
|
/* kick the next pending lock into having a go */
|
386 |
|
|
list_del_init(&fl->fl_u.afs.link);
|
387 |
|
|
afs_lock_may_be_available(vnode);
|
388 |
|
|
}
|
389 |
|
|
} else {
|
390 |
|
|
list_del_init(&fl->fl_u.afs.link);
|
391 |
|
|
}
|
392 |
|
|
spin_unlock(&vnode->lock);
|
393 |
|
|
goto error;
|
394 |
|
|
|
395 |
|
|
acquired_server_lock:
|
396 |
|
|
/* we've acquired a server lock, but it needs to be renewed after 5
|
397 |
|
|
* mins */
|
398 |
|
|
spin_lock(&vnode->lock);
|
399 |
|
|
afs_schedule_lock_extension(vnode);
|
400 |
|
|
if (type == AFS_LOCK_READ)
|
401 |
|
|
set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
|
402 |
|
|
else
|
403 |
|
|
set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
|
404 |
|
|
sharing_existing_lock:
|
405 |
|
|
/* the lock has been granted as far as we're concerned... */
|
406 |
|
|
fl->fl_u.afs.state = AFS_LOCK_GRANTED;
|
407 |
|
|
list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
|
408 |
|
|
given_lock:
|
409 |
|
|
/* ... but we do still need to get the VFS's blessing */
|
410 |
|
|
ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING)));
|
411 |
|
|
ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) |
|
412 |
|
|
(1 << AFS_VNODE_WRITELOCKED))) != 0);
|
413 |
|
|
ret = posix_lock_file(file, fl, NULL);
|
414 |
|
|
if (ret < 0)
|
415 |
|
|
goto vfs_rejected_lock;
|
416 |
|
|
spin_unlock(&vnode->lock);
|
417 |
|
|
|
418 |
|
|
/* again, make sure we've got a callback on this file and, again, make
|
419 |
|
|
* sure that our view of the data version is up to date (we ignore
|
420 |
|
|
* errors incurred here and deal with the consequences elsewhere) */
|
421 |
|
|
afs_vnode_fetch_status(vnode, NULL, key);
|
422 |
|
|
|
423 |
|
|
error:
|
424 |
|
|
unlock_kernel();
|
425 |
|
|
_leave(" = %d", ret);
|
426 |
|
|
return ret;
|
427 |
|
|
|
428 |
|
|
vfs_rejected_lock:
|
429 |
|
|
/* the VFS rejected the lock we just obtained, so we have to discard
|
430 |
|
|
* what we just got */
|
431 |
|
|
_debug("vfs refused %d", ret);
|
432 |
|
|
list_del_init(&fl->fl_u.afs.link);
|
433 |
|
|
if (list_empty(&vnode->granted_locks))
|
434 |
|
|
afs_defer_unlock(vnode, key);
|
435 |
|
|
spin_unlock(&vnode->lock);
|
436 |
|
|
goto abort_attempt;
|
437 |
|
|
}
|
438 |
|
|
|
439 |
|
|
/*
|
440 |
|
|
* unlock on a file on the server
|
441 |
|
|
*/
|
442 |
|
|
static int afs_do_unlk(struct file *file, struct file_lock *fl)
|
443 |
|
|
{
|
444 |
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
|
445 |
|
|
struct key *key = file->private_data;
|
446 |
|
|
int ret;
|
447 |
|
|
|
448 |
|
|
_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
|
449 |
|
|
|
450 |
|
|
/* only whole-file unlocks are supported */
|
451 |
|
|
if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
|
452 |
|
|
return -EINVAL;
|
453 |
|
|
|
454 |
|
|
fl->fl_ops = &afs_lock_ops;
|
455 |
|
|
INIT_LIST_HEAD(&fl->fl_u.afs.link);
|
456 |
|
|
fl->fl_u.afs.state = AFS_LOCK_PENDING;
|
457 |
|
|
|
458 |
|
|
spin_lock(&vnode->lock);
|
459 |
|
|
ret = posix_lock_file(file, fl, NULL);
|
460 |
|
|
if (ret < 0) {
|
461 |
|
|
spin_unlock(&vnode->lock);
|
462 |
|
|
_leave(" = %d [vfs]", ret);
|
463 |
|
|
return ret;
|
464 |
|
|
}
|
465 |
|
|
|
466 |
|
|
/* discard the server lock only if all granted locks are gone */
|
467 |
|
|
if (list_empty(&vnode->granted_locks))
|
468 |
|
|
afs_defer_unlock(vnode, key);
|
469 |
|
|
spin_unlock(&vnode->lock);
|
470 |
|
|
_leave(" = 0");
|
471 |
|
|
return 0;
|
472 |
|
|
}
|
473 |
|
|
|
474 |
|
|
/*
|
475 |
|
|
* return information about a lock we currently hold, if indeed we hold one
|
476 |
|
|
*/
|
477 |
|
|
static int afs_do_getlk(struct file *file, struct file_lock *fl)
|
478 |
|
|
{
|
479 |
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
|
480 |
|
|
struct key *key = file->private_data;
|
481 |
|
|
int ret, lock_count;
|
482 |
|
|
|
483 |
|
|
_enter("");
|
484 |
|
|
|
485 |
|
|
fl->fl_type = F_UNLCK;
|
486 |
|
|
|
487 |
|
|
mutex_lock(&vnode->vfs_inode.i_mutex);
|
488 |
|
|
|
489 |
|
|
/* check local lock records first */
|
490 |
|
|
ret = 0;
|
491 |
|
|
posix_test_lock(file, fl);
|
492 |
|
|
if (fl->fl_type == F_UNLCK) {
|
493 |
|
|
/* no local locks; consult the server */
|
494 |
|
|
ret = afs_vnode_fetch_status(vnode, NULL, key);
|
495 |
|
|
if (ret < 0)
|
496 |
|
|
goto error;
|
497 |
|
|
lock_count = vnode->status.lock_count;
|
498 |
|
|
if (lock_count) {
|
499 |
|
|
if (lock_count > 0)
|
500 |
|
|
fl->fl_type = F_RDLCK;
|
501 |
|
|
else
|
502 |
|
|
fl->fl_type = F_WRLCK;
|
503 |
|
|
fl->fl_start = 0;
|
504 |
|
|
fl->fl_end = OFFSET_MAX;
|
505 |
|
|
}
|
506 |
|
|
}
|
507 |
|
|
|
508 |
|
|
error:
|
509 |
|
|
mutex_unlock(&vnode->vfs_inode.i_mutex);
|
510 |
|
|
_leave(" = %d [%hd]", ret, fl->fl_type);
|
511 |
|
|
return ret;
|
512 |
|
|
}
|
513 |
|
|
|
514 |
|
|
/*
|
515 |
|
|
* manage POSIX locks on a file
|
516 |
|
|
*/
|
517 |
|
|
int afs_lock(struct file *file, int cmd, struct file_lock *fl)
|
518 |
|
|
{
|
519 |
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
|
520 |
|
|
|
521 |
|
|
_enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}",
|
522 |
|
|
vnode->fid.vid, vnode->fid.vnode, cmd,
|
523 |
|
|
fl->fl_type, fl->fl_flags,
|
524 |
|
|
(long long) fl->fl_start, (long long) fl->fl_end);
|
525 |
|
|
|
526 |
|
|
/* AFS doesn't support mandatory locks */
|
527 |
|
|
if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
|
528 |
|
|
return -ENOLCK;
|
529 |
|
|
|
530 |
|
|
if (IS_GETLK(cmd))
|
531 |
|
|
return afs_do_getlk(file, fl);
|
532 |
|
|
if (fl->fl_type == F_UNLCK)
|
533 |
|
|
return afs_do_unlk(file, fl);
|
534 |
|
|
return afs_do_setlk(file, fl);
|
535 |
|
|
}
|
536 |
|
|
|
537 |
|
|
/*
|
538 |
|
|
* manage FLOCK locks on a file
|
539 |
|
|
*/
|
540 |
|
|
int afs_flock(struct file *file, int cmd, struct file_lock *fl)
|
541 |
|
|
{
|
542 |
|
|
struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
|
543 |
|
|
|
544 |
|
|
_enter("{%x:%u},%d,{t=%x,fl=%x}",
|
545 |
|
|
vnode->fid.vid, vnode->fid.vnode, cmd,
|
546 |
|
|
fl->fl_type, fl->fl_flags);
|
547 |
|
|
|
548 |
|
|
/*
|
549 |
|
|
* No BSD flocks over NFS allowed.
|
550 |
|
|
* Note: we could try to fake a POSIX lock request here by
|
551 |
|
|
* using ((u32) filp | 0x80000000) or some such as the pid.
|
552 |
|
|
* Not sure whether that would be unique, though, or whether
|
553 |
|
|
* that would break in other places.
|
554 |
|
|
*/
|
555 |
|
|
if (!(fl->fl_flags & FL_FLOCK))
|
556 |
|
|
return -ENOLCK;
|
557 |
|
|
|
558 |
|
|
/* we're simulating flock() locks using posix locks on the server */
|
559 |
|
|
fl->fl_owner = (fl_owner_t) file;
|
560 |
|
|
fl->fl_start = 0;
|
561 |
|
|
fl->fl_end = OFFSET_MAX;
|
562 |
|
|
|
563 |
|
|
if (fl->fl_type == F_UNLCK)
|
564 |
|
|
return afs_do_unlk(file, fl);
|
565 |
|
|
return afs_do_setlk(file, fl);
|
566 |
|
|
}
|
567 |
|
|
|
568 |
|
|
/*
|
569 |
|
|
* the POSIX lock management core VFS code copies the lock record and adds the
|
570 |
|
|
* copy into its own list, so we need to add that copy to the vnode's lock
|
571 |
|
|
* queue in the same place as the original (which will be deleted shortly
|
572 |
|
|
* after)
|
573 |
|
|
*/
|
574 |
|
|
static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl)
|
575 |
|
|
{
|
576 |
|
|
_enter("");
|
577 |
|
|
|
578 |
|
|
list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
|
579 |
|
|
}
|
580 |
|
|
|
581 |
|
|
/*
|
582 |
|
|
* need to remove this lock from the vnode queue when it's removed from the
|
583 |
|
|
* VFS's list
|
584 |
|
|
*/
|
585 |
|
|
static void afs_fl_release_private(struct file_lock *fl)
|
586 |
|
|
{
|
587 |
|
|
_enter("");
|
588 |
|
|
|
589 |
|
|
list_del_init(&fl->fl_u.afs.link);
|
590 |
|
|
}
|