Re: GFS2 Filesystem [15/16]

Re: GFS2 Filesystem [15/16]

[Pavel Machek]

> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/types.h>
> +#include <linux/fs.h>
> +#include <linux/smp_lock.h>
> +
> +#include "../../lm_interface.h"

ugly...

> +{
> +	char *c;
> +	unsigned int jid;
> +	struct nolock_lockspace *nl;
> +
> +	/* If there is a "jid=" in the hostdata, return that jid.
> +	   Otherwise, return zero. */

useful comment of the year 2006....

> +	c = strstr(host_data, "jid=");
> +	if (!c)
> +		jid = 0;
> +	else {
> +		c += 4;
> +		sscanf(c, "%u", &jid);
> +	}
> +

...
> +
> +static int nolock_get_lock(lm_lockspace_t *lockspace, struct lm_lockname *name,
> +			   lm_lock_t **lockp)
> +{
> +	*lockp = (lm_lock_t *)lockspace;


typedef abuse?

-- 
Thanks, Sharp!

GFS2 Filesystem [15/16]

[Steven Whitehouse]

[PATCH 15/16] GFS2: 

The "nolock" locking module provides locking services for single node
GFS2 set ups and is also useful for testing.



Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>


 fs/gfs2/locking/nolock/Makefile |    3 
 fs/gfs2/locking/nolock/main.c   |  268 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 271 insertions(+)

--- /dev/null
+++ b/fs/gfs2/locking/nolock/main.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/smp_lock.h>
+
+#include "../../lm_interface.h"
+
+struct nolock_lockspace {
+	unsigned int nl_lvb_size;
+};
+
+struct lm_lockops nolock_ops;
+
+static int nolock_mount(char *table_name, char *host_data,
+			lm_callback_t cb, lm_fsdata_t *fsdata,
+			unsigned int min_lvb_size, int flags,
+			struct lm_lockstruct *lockstruct,
+			struct kobject *fskobj)
+{
+	char *c;
+	unsigned int jid;
+	struct nolock_lockspace *nl;
+
+	/* If there is a "jid=" in the hostdata, return that jid.
+	   Otherwise, return zero. */
+
+	c = strstr(host_data, "jid=");
+	if (!c)
+		jid = 0;
+	else {
+		c += 4;
+		sscanf(c, "%u", &jid);
+	}
+
+	nl = kmalloc(sizeof(struct nolock_lockspace), GFP_KERNEL);
+	if (!nl)
+		return -ENOMEM;
+
+	memset(nl, 0, sizeof(struct nolock_lockspace));
+	nl->nl_lvb_size = min_lvb_size;
+
+	lockstruct->ls_jid = jid;
+	lockstruct->ls_first = 1;
+	lockstruct->ls_lvb_size = min_lvb_size;
+	lockstruct->ls_lockspace = (lm_lockspace_t *)nl;
+	lockstruct->ls_ops = &nolock_ops;
+	lockstruct->ls_flags = LM_LSFLAG_LOCAL;
+
+	return 0;
+}
+
+static void nolock_others_may_mount(lm_lockspace_t *lockspace)
+{
+}
+
+static void nolock_unmount(lm_lockspace_t *lockspace)
+{
+	struct nolock_lockspace *nl = (struct nolock_lockspace *)lockspace;
+	kfree(nl);
+}
+
+static void nolock_withdraw(lm_lockspace_t *lockspace)
+{
+}
+
+/**
+ * nolock_get_lock - get a lm_lock_t given a descripton of the lock
+ * @lockspace: the lockspace the lock lives in
+ * @name: the name of the lock
+ * @lockp: return the lm_lock_t here
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+static int nolock_get_lock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			   lm_lock_t **lockp)
+{
+	*lockp = (lm_lock_t *)lockspace;
+	return 0;
+}
+
+/**
+ * nolock_put_lock - get rid of a lock structure
+ * @lock: the lock to throw away
+ *
+ */
+
+static void nolock_put_lock(lm_lock_t *lock)
+{
+}
+
+/**
+ * nolock_lock - acquire a lock
+ * @lock: the lock to manipulate
+ * @cur_state: the current state
+ * @req_state: the requested state
+ * @flags: modifier flags
+ *
+ * Returns: A bitmap of LM_OUT_*
+ */
+
+static unsigned int nolock_lock(lm_lock_t *lock, unsigned int cur_state,
+				unsigned int req_state, unsigned int flags)
+{
+	return req_state | LM_OUT_CACHEABLE;
+}
+
+/**
+ * nolock_unlock - unlock a lock
+ * @lock: the lock to manipulate
+ * @cur_state: the current state
+ *
+ * Returns: 0
+ */
+
+static unsigned int nolock_unlock(lm_lock_t *lock, unsigned int cur_state)
+{
+	return 0;
+}
+
+static void nolock_cancel(lm_lock_t *lock)
+{
+}
+
+/**
+ * nolock_hold_lvb - hold on to a lock value block
+ * @lock: the lock the LVB is associated with
+ * @lvbp: return the lm_lvb_t here
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+static int nolock_hold_lvb(lm_lock_t *lock, char **lvbp)
+{
+	struct nolock_lockspace *nl = (struct nolock_lockspace *)lock;
+	int error = 0;
+
+	*lvbp = kmalloc(nl->nl_lvb_size, GFP_KERNEL);
+	if (*lvbp)
+		memset(*lvbp, 0, nl->nl_lvb_size);
+	else
+		error = -ENOMEM;
+
+	return error;
+}
+
+/**
+ * nolock_unhold_lvb - release a LVB
+ * @lock: the lock the LVB is associated with
+ * @lvb: the lock value block
+ *
+ */
+
+static void nolock_unhold_lvb(lm_lock_t *lock, char *lvb)
+{
+	kfree(lvb);
+}
+
+/**
+ * nolock_sync_lvb - sync out the value of a lvb
+ * @lock: the lock the LVB is associated with
+ * @lvb: the lock value block
+ *
+ */
+
+static void nolock_sync_lvb(lm_lock_t *lock, char *lvb)
+{
+}
+
+static int nolock_plock_get(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			    struct file *file, struct file_lock *fl)
+{
+	struct file_lock *tmp;
+
+	lock_kernel();
+	tmp = posix_test_lock(file, fl);
+	fl->fl_type = F_UNLCK;
+	if (tmp)
+		memcpy(fl, tmp, sizeof(struct file_lock));
+	unlock_kernel();
+
+	return 0;
+}
+
+static int nolock_plock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			struct file *file, int cmd, struct file_lock *fl)
+{
+	int error;
+	lock_kernel();
+	error = posix_lock_file_wait(file, fl);
+	unlock_kernel();
+	return error;
+}
+
+static int nolock_punlock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			  struct file *file, struct file_lock *fl)
+{
+	int error;
+	lock_kernel();
+	error = posix_lock_file_wait(file, fl);
+	unlock_kernel();
+	return error;
+}
+
+static void nolock_recovery_done(lm_lockspace_t *lockspace, unsigned int jid,
+				 unsigned int message)
+{
+}
+
+struct lm_lockops nolock_ops = {
+	.lm_proto_name = "lock_nolock",
+	.lm_mount = nolock_mount,
+	.lm_others_may_mount = nolock_others_may_mount,
+	.lm_unmount = nolock_unmount,
+	.lm_withdraw = nolock_withdraw,
+	.lm_get_lock = nolock_get_lock,
+	.lm_put_lock = nolock_put_lock,
+	.lm_lock = nolock_lock,
+	.lm_unlock = nolock_unlock,
+	.lm_cancel = nolock_cancel,
+	.lm_hold_lvb = nolock_hold_lvb,
+	.lm_unhold_lvb = nolock_unhold_lvb,
+	.lm_sync_lvb = nolock_sync_lvb,
+	.lm_plock_get = nolock_plock_get,
+	.lm_plock = nolock_plock,
+	.lm_punlock = nolock_punlock,
+	.lm_recovery_done = nolock_recovery_done,
+	.lm_owner = THIS_MODULE,
+};
+
+int __init init_nolock(void)
+{
+	int error;
+
+	error = gfs_register_lockproto(&nolock_ops);
+	if (error) {
+		printk("lock_nolock: can't register protocol: %d\n", error);
+		return error;
+	}
+
+	printk("Lock_Nolock (built %s %s) installed\n", __DATE__, __TIME__);
+	return 0;
+}
+
+void __exit exit_nolock(void)
+{
+	gfs_unregister_lockproto(&nolock_ops);
+}
+
+module_init(init_nolock);
+module_exit(exit_nolock);
+
+MODULE_DESCRIPTION("GFS Nolock Locking Module");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
--- /dev/null
+++ b/fs/gfs2/locking/nolock/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_GFS2_FS) += lock_nolock.o
+lock_nolock-y := main.o
+

Re: GFS2 Filesystem [15/16]

[Pekka Enberg]

On 2/24/06, Steven Whitehouse <swhiteho@redhat.com> wrote:
> +       nl = kmalloc(sizeof(struct nolock_lockspace), GFP_KERNEL);
> +       if (!nl)
> +               return -ENOMEM;
> +
> +       memset(nl, 0, sizeof(struct nolock_lockspace));

kzalloc, please.

> +       *lvbp = kmalloc(nl->nl_lvb_size, GFP_KERNEL);
> +       if (*lvbp)
> +               memset(*lvbp, 0, nl->nl_lvb_size);
> +       else
> +               error = -ENOMEM;

Likewise.

                                   Pekka

Re: GFS2 Filesystem [15/16]

[Steven Whitehouse]

Hi,

On Wed, 2006-02-22 at 18:54 +0000, Pavel Machek wrote:
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/module.h>
> > +#include <linux/init.h>
> > +#include <linux/types.h>
> > +#include <linux/fs.h>
> > +#include <linux/smp_lock.h>
> > +
> > +#include "../../lm_interface.h"
> 
> ugly...
> 
Agreed (see below)

> > +{
> > +	char *c;
> > +	unsigned int jid;
> > +	struct nolock_lockspace *nl;
> > +
> > +	/* If there is a "jid=" in the hostdata, return that jid.
> > +	   Otherwise, return zero. */
> 
> useful comment of the year 2006....
> 
> > +	c = strstr(host_data, "jid=");
> > +	if (!c)
> > +		jid = 0;
> > +	else {
> > +		c += 4;
> > +		sscanf(c, "%u", &jid);
> > +	}
> > +
> 
> ...
> > +
> > +static int nolock_get_lock(lm_lockspace_t *lockspace, struct lm_lockname *name,
> > +			   lm_lock_t **lockp)
> > +{
> > +	*lockp = (lm_lock_t *)lockspace;
> 
> 
> typedef abuse?
> 
The lock module interface has been left identical to that in GFS1 for
the time being so that it is possible to share lock modules between the
two versions. There are a few things which could be tidied up if we were
to change the interface, and we may well do that, but we've been holding
off as long as possible if only to make testing easier.

Since you've brought the subject up, we'll add it to out list :-) Thanks
for the suggestions,

Steve.