dlm: move plock code from gfs2
Move the code that handles cluster posix locks from gfs2 into the dlm
so that it can be used by both gfs2 and ocfs2.
Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
new file mode 100644
index 0000000..d6d6e37
--- /dev/null
+++ b/fs/dlm/plock.c
@@ -0,0 +1,439 @@
+/*
+ * Copyright (C) 2005-2008 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/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+#include <linux/dlm.h>
+#include <linux/dlm_plock.h>
+
+#include "dlm_internal.h"
+#include "lockspace.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 dlm_plock_info info;
+};
+
+struct plock_xop {
+ struct plock_op xop;
+ void *callback;
+ void *fl;
+ void *file;
+ struct file_lock flc;
+};
+
+
+static inline void set_version(struct dlm_plock_info *info)
+{
+ info->version[0] = DLM_PLOCK_VERSION_MAJOR;
+ info->version[1] = DLM_PLOCK_VERSION_MINOR;
+ info->version[2] = DLM_PLOCK_VERSION_PATCH;
+}
+
+static int check_version(struct dlm_plock_info *info)
+{
+ if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
+ (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
+ log_print("plock device version mismatch: "
+ "kernel (%u.%u.%u), user (%u.%u.%u)",
+ DLM_PLOCK_VERSION_MAJOR,
+ DLM_PLOCK_VERSION_MINOR,
+ DLM_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 dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
+ int cmd, struct file_lock *fl)
+{
+ struct dlm_ls *ls;
+ struct plock_op *op;
+ struct plock_xop *xop;
+ int rv;
+
+ ls = dlm_find_lockspace_local(lockspace);
+ if (!ls)
+ return -EINVAL;
+
+ xop = kzalloc(sizeof(*xop), GFP_KERNEL);
+ if (!xop) {
+ rv = -ENOMEM;
+ goto out;
+ }
+
+ op = &xop->xop;
+ op->info.optype = DLM_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->ls_global_id;
+ op->info.number = number;
+ op->info.start = fl->fl_start;
+ op->info.end = fl->fl_end;
+ if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
+ /* fl_owner is lockd which doesn't distinguish
+ processes on the nfs client */
+ op->info.owner = (__u64) fl->fl_pid;
+ xop->callback = fl->fl_lmops->fl_grant;
+ locks_init_lock(&xop->flc);
+ locks_copy_lock(&xop->flc, fl);
+ xop->fl = fl;
+ xop->file = file;
+ } else {
+ op->info.owner = (__u64)(long) fl->fl_owner;
+ xop->callback = NULL;
+ }
+
+ send_op(op);
+
+ if (xop->callback == NULL)
+ wait_event(recv_wq, (op->done != 0));
+ else {
+ rv = -EINPROGRESS;
+ goto out;
+ }
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&op->list)) {
+ log_error(ls, "dlm_posix_lock: op on list %llx",
+ (unsigned long long)number);
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ rv = op->info.rv;
+
+ if (!rv) {
+ if (posix_lock_file_wait(file, fl) < 0)
+ log_error(ls, "dlm_posix_lock: vfs lock error %llx",
+ (unsigned long long)number);
+ }
+
+ kfree(xop);
+out:
+ dlm_put_lockspace(ls);
+ return rv;
+}
+EXPORT_SYMBOL_GPL(dlm_posix_lock);
+
+/* Returns failure iff a succesful lock operation should be canceled */
+static int dlm_plock_callback(struct plock_op *op)
+{
+ struct file *file;
+ struct file_lock *fl;
+ struct file_lock *flc;
+ int (*notify)(void *, void *, int) = NULL;
+ struct plock_xop *xop = (struct plock_xop *)op;
+ int rv = 0;
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&op->list)) {
+ log_print("dlm_plock_callback: op on list %llx",
+ (unsigned long long)op->info.number);
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ /* check if the following 2 are still valid or make a copy */
+ file = xop->file;
+ flc = &xop->flc;
+ fl = xop->fl;
+ notify = xop->callback;
+
+ if (op->info.rv) {
+ notify(flc, NULL, op->info.rv);
+ goto out;
+ }
+
+ /* got fs lock; bookkeep locally as well: */
+ flc->fl_flags &= ~FL_SLEEP;
+ if (posix_lock_file(file, flc, NULL)) {
+ /*
+ * This can only happen in the case of kmalloc() failure.
+ * The filesystem's own lock is the authoritative lock,
+ * so a failure to get the lock locally is not a disaster.
+ * As long as the fs cannot reliably cancel locks (especially
+ * in a low-memory situation), we're better off ignoring
+ * this failure than trying to recover.
+ */
+ log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
+ (unsigned long long)op->info.number, file, fl);
+ }
+
+ rv = notify(flc, NULL, 0);
+ if (rv) {
+ /* XXX: We need to cancel the fs lock here: */
+ log_print("dlm_plock_callback: lock granted after lock request "
+ "failed; dangling lock!\n");
+ goto out;
+ }
+
+out:
+ kfree(xop);
+ return rv;
+}
+
+int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
+ struct file_lock *fl)
+{
+ struct dlm_ls *ls;
+ struct plock_op *op;
+ int rv;
+
+ ls = dlm_find_lockspace_local(lockspace);
+ if (!ls)
+ return -EINVAL;
+
+ op = kzalloc(sizeof(*op), GFP_KERNEL);
+ if (!op) {
+ rv = -ENOMEM;
+ goto out;
+ }
+
+ if (posix_lock_file_wait(file, fl) < 0)
+ log_error(ls, "dlm_posix_unlock: vfs unlock error %llx",
+ (unsigned long long)number);
+
+ op->info.optype = DLM_PLOCK_OP_UNLOCK;
+ op->info.pid = fl->fl_pid;
+ op->info.fsid = ls->ls_global_id;
+ op->info.number = number;
+ op->info.start = fl->fl_start;
+ op->info.end = fl->fl_end;
+ if (fl->fl_lmops && fl->fl_lmops->fl_grant)
+ op->info.owner = (__u64) fl->fl_pid;
+ else
+ 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)) {
+ log_error(ls, "dlm_posix_unlock: op on list %llx",
+ (unsigned long long)number);
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ rv = op->info.rv;
+
+ if (rv == -ENOENT)
+ rv = 0;
+
+ kfree(op);
+out:
+ dlm_put_lockspace(ls);
+ return rv;
+}
+EXPORT_SYMBOL_GPL(dlm_posix_unlock);
+
+int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
+ struct file_lock *fl)
+{
+ struct dlm_ls *ls;
+ struct plock_op *op;
+ int rv;
+
+ ls = dlm_find_lockspace_local(lockspace);
+ if (!ls)
+ return -EINVAL;
+
+ op = kzalloc(sizeof(*op), GFP_KERNEL);
+ if (!op) {
+ rv = -ENOMEM;
+ goto out;
+ }
+
+ op->info.optype = DLM_PLOCK_OP_GET;
+ op->info.pid = fl->fl_pid;
+ op->info.ex = (fl->fl_type == F_WRLCK);
+ op->info.fsid = ls->ls_global_id;
+ op->info.number = number;
+ op->info.start = fl->fl_start;
+ op->info.end = fl->fl_end;
+ if (fl->fl_lmops && fl->fl_lmops->fl_grant)
+ op->info.owner = (__u64) fl->fl_pid;
+ else
+ 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)) {
+ log_error(ls, "dlm_posix_get: op on list %llx",
+ (unsigned long long)number);
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
+ -ENOENT if there are no locks on the file */
+
+ rv = op->info.rv;
+
+ fl->fl_type = F_UNLCK;
+ if (rv == -ENOENT)
+ rv = 0;
+ 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;
+ rv = 0;
+ }
+
+ kfree(op);
+out:
+ dlm_put_lockspace(ls);
+ return rv;
+}
+EXPORT_SYMBOL_GPL(dlm_posix_get);
+
+/* 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 dlm_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 dlm_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) {
+ struct plock_xop *xop;
+ xop = (struct plock_xop *)op;
+ if (xop->callback)
+ count = dlm_plock_callback(op);
+ else
+ wake_up(&recv_wq);
+ } else
+ log_print("dev_write no op %x %llx", info.fsid,
+ (unsigned long long)info.number);
+ return count;
+}
+
+static unsigned int dev_poll(struct file *file, poll_table *wait)
+{
+ unsigned int mask = 0;
+
+ poll_wait(file, &send_wq, wait);
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&send_list))
+ mask = POLLIN | POLLRDNORM;
+ spin_unlock(&ops_lock);
+
+ return mask;
+}
+
+static const 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 = DLM_PLOCK_MISC_NAME,
+ .fops = &dev_fops
+};
+
+int dlm_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)
+ log_print("dlm_plock_init: misc_register failed %d", rv);
+ return rv;
+}
+
+void dlm_plock_exit(void)
+{
+ if (misc_deregister(&plock_dev_misc) < 0)
+ log_print("dlm_plock_exit: misc_deregister failed");
+}
+