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path: root/fs/gfs2/locking/dlm/plock.c
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-rw-r--r--fs/gfs2/locking/dlm/plock.c301
1 files changed, 301 insertions, 0 deletions
diff --git a/fs/gfs2/locking/dlm/plock.c b/fs/gfs2/locking/dlm/plock.c
new file mode 100644
index 00000000000..7365aec9511
--- /dev/null
+++ b/fs/gfs2/locking/dlm/plock.c
@@ -0,0 +1,301 @@
+/*
+ * Copyright (C) 2005 Red Hat, Inc. All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License version 2.
+ */
+
+#include <linux/miscdevice.h>
+#include <linux/lock_dlm_plock.h>
+
+#include "lock_dlm.h"
+
+
+static spinlock_t ops_lock;
+static struct list_head send_list;
+static struct list_head recv_list;
+static wait_queue_head_t send_wq;
+static wait_queue_head_t recv_wq;
+
+struct plock_op {
+ struct list_head list;
+ int done;
+ struct gdlm_plock_info info;
+};
+
+static inline void set_version(struct gdlm_plock_info *info)
+{
+ info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
+ info->version[1] = GDLM_PLOCK_VERSION_MINOR;
+ info->version[2] = GDLM_PLOCK_VERSION_PATCH;
+}
+
+static int check_version(struct gdlm_plock_info *info)
+{
+ if ((GDLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
+ (GDLM_PLOCK_VERSION_MINOR < info->version[1])) {
+ log_error("plock device version mismatch: "
+ "kernel (%u.%u.%u), user (%u.%u.%u)",
+ GDLM_PLOCK_VERSION_MAJOR,
+ GDLM_PLOCK_VERSION_MINOR,
+ GDLM_PLOCK_VERSION_PATCH,
+ info->version[0],
+ info->version[1],
+ info->version[2]);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static void send_op(struct plock_op *op)
+{
+ set_version(&op->info);
+ INIT_LIST_HEAD(&op->list);
+ spin_lock(&ops_lock);
+ list_add_tail(&op->list, &send_list);
+ spin_unlock(&ops_lock);
+ wake_up(&send_wq);
+}
+
+int gdlm_plock(void *lockspace, struct lm_lockname *name,
+ struct file *file, int cmd, struct file_lock *fl)
+{
+ struct gdlm_ls *ls = lockspace;
+ struct plock_op *op;
+ int rv;
+
+ op = kzalloc(sizeof(*op), GFP_KERNEL);
+ if (!op)
+ return -ENOMEM;
+
+ op->info.optype = GDLM_PLOCK_OP_LOCK;
+ op->info.pid = fl->fl_pid;
+ op->info.ex = (fl->fl_type == F_WRLCK);
+ op->info.wait = IS_SETLKW(cmd);
+ op->info.fsid = ls->id;
+ op->info.number = name->ln_number;
+ op->info.start = fl->fl_start;
+ op->info.end = fl->fl_end;
+ op->info.owner = (__u64)(long) fl->fl_owner;
+
+ send_op(op);
+ wait_event(recv_wq, (op->done != 0));
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&op->list)) {
+ printk(KERN_INFO "plock op on list\n");
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ rv = op->info.rv;
+
+ if (!rv) {
+ if (posix_lock_file_wait(file, fl) < 0)
+ log_error("gdlm_plock: vfs lock error %x,%llx",
+ name->ln_type,
+ (unsigned long long)name->ln_number);
+ }
+
+ kfree(op);
+ return rv;
+}
+
+int gdlm_punlock(void *lockspace, struct lm_lockname *name,
+ struct file *file, struct file_lock *fl)
+{
+ struct gdlm_ls *ls = lockspace;
+ struct plock_op *op;
+ int rv;
+
+ op = kzalloc(sizeof(*op), GFP_KERNEL);
+ if (!op)
+ return -ENOMEM;
+
+ if (posix_lock_file_wait(file, fl) < 0)
+ log_error("gdlm_punlock: vfs unlock error %x,%llx",
+ name->ln_type, (unsigned long long)name->ln_number);
+
+ op->info.optype = GDLM_PLOCK_OP_UNLOCK;
+ op->info.pid = fl->fl_pid;
+ op->info.fsid = ls->id;
+ op->info.number = name->ln_number;
+ op->info.start = fl->fl_start;
+ op->info.end = fl->fl_end;
+ op->info.owner = (__u64)(long) fl->fl_owner;
+
+ send_op(op);
+ wait_event(recv_wq, (op->done != 0));
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&op->list)) {
+ printk(KERN_INFO "punlock op on list\n");
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ rv = op->info.rv;
+
+ kfree(op);
+ return rv;
+}
+
+int gdlm_plock_get(void *lockspace, struct lm_lockname *name,
+ struct file *file, struct file_lock *fl)
+{
+ struct gdlm_ls *ls = lockspace;
+ struct plock_op *op;
+ int rv;
+
+ op = kzalloc(sizeof(*op), GFP_KERNEL);
+ if (!op)
+ return -ENOMEM;
+
+ op->info.optype = GDLM_PLOCK_OP_GET;
+ op->info.pid = fl->fl_pid;
+ op->info.ex = (fl->fl_type == F_WRLCK);
+ op->info.fsid = ls->id;
+ op->info.number = name->ln_number;
+ op->info.start = fl->fl_start;
+ op->info.end = fl->fl_end;
+
+ send_op(op);
+ wait_event(recv_wq, (op->done != 0));
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&op->list)) {
+ printk(KERN_INFO "plock_get op on list\n");
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ rv = op->info.rv;
+
+ if (rv == 0)
+ fl->fl_type = F_UNLCK;
+ else if (rv > 0) {
+ fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
+ fl->fl_pid = op->info.pid;
+ fl->fl_start = op->info.start;
+ fl->fl_end = op->info.end;
+ }
+
+ kfree(op);
+ return rv;
+}
+
+/* a read copies out one plock request from the send list */
+static ssize_t dev_read(struct file *file, char __user *u, size_t count,
+ loff_t *ppos)
+{
+ struct gdlm_plock_info info;
+ struct plock_op *op = NULL;
+
+ if (count < sizeof(info))
+ return -EINVAL;
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&send_list)) {
+ op = list_entry(send_list.next, struct plock_op, list);
+ list_move(&op->list, &recv_list);
+ memcpy(&info, &op->info, sizeof(info));
+ }
+ spin_unlock(&ops_lock);
+
+ if (!op)
+ return -EAGAIN;
+
+ if (copy_to_user(u, &info, sizeof(info)))
+ return -EFAULT;
+ return sizeof(info);
+}
+
+/* a write copies in one plock result that should match a plock_op
+ on the recv list */
+static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
+ loff_t *ppos)
+{
+ struct gdlm_plock_info info;
+ struct plock_op *op;
+ int found = 0;
+
+ if (count != sizeof(info))
+ return -EINVAL;
+
+ if (copy_from_user(&info, u, sizeof(info)))
+ return -EFAULT;
+
+ if (check_version(&info))
+ return -EINVAL;
+
+ spin_lock(&ops_lock);
+ list_for_each_entry(op, &recv_list, list) {
+ if (op->info.fsid == info.fsid && op->info.number == info.number &&
+ op->info.owner == info.owner) {
+ list_del_init(&op->list);
+ found = 1;
+ op->done = 1;
+ memcpy(&op->info, &info, sizeof(info));
+ break;
+ }
+ }
+ spin_unlock(&ops_lock);
+
+ if (found)
+ wake_up(&recv_wq);
+ else
+ printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
+ (unsigned long long)info.number);
+ return count;
+}
+
+static unsigned int dev_poll(struct file *file, poll_table *wait)
+{
+ poll_wait(file, &send_wq, wait);
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&send_list)) {
+ spin_unlock(&ops_lock);
+ return POLLIN | POLLRDNORM;
+ }
+ spin_unlock(&ops_lock);
+ return 0;
+}
+
+static struct file_operations dev_fops = {
+ .read = dev_read,
+ .write = dev_write,
+ .poll = dev_poll,
+ .owner = THIS_MODULE
+};
+
+static struct miscdevice plock_dev_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = GDLM_PLOCK_MISC_NAME,
+ .fops = &dev_fops
+};
+
+int gdlm_plock_init(void)
+{
+ int rv;
+
+ spin_lock_init(&ops_lock);
+ INIT_LIST_HEAD(&send_list);
+ INIT_LIST_HEAD(&recv_list);
+ init_waitqueue_head(&send_wq);
+ init_waitqueue_head(&recv_wq);
+
+ rv = misc_register(&plock_dev_misc);
+ if (rv)
+ printk(KERN_INFO "gdlm_plock_init: misc_register failed %d",
+ rv);
+ return rv;
+}
+
+void gdlm_plock_exit(void)
+{
+ if (misc_deregister(&plock_dev_misc) < 0)
+ printk(KERN_INFO "gdlm_plock_exit: misc_deregister failed");
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-23 19:38:14 +0000