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linux/fs/ocfs2/stack_o2cb.c
Joel Becker 1c520dfbf3 ocfs2: Provide the ocfs2_dlm_lvb_valid() stack API. 
The Lock Value Block (LVB) of a DLM lock can be lost when nodes die and
the DLM cannot reconstruct its state.  Clients of the DLM need to know
this.

ocfs2's internal DLM, o2dlm, explicitly zeroes out the LVB when it loses
track of the state.  This is not a standard behavior, but ocfs2 has
always relied on it.  Thus, an o2dlm LVB is always "valid".

ocfs2 now supports both o2dlm and fs/dlm via the stack glue.  When
fs/dlm loses track of an LVBs state, it sets a flag
(DLM_SBF_VALNOTVALID) on the Lock Status Block (LKSB).  The contents of
the LVB may be garbage or merely stale.

ocfs2 doesn't want to try to guess at the validity of the stale LVB.
Instead, it should be checking the VALNOTVALID flag.  As this is the
'standard' way of treating LVBs, we will promote this behavior.

We add a stack glue API ocfs2_dlm_lvb_valid().  It returns non-zero when
the LVB is valid.  o2dlm will always return valid, while fs/dlm will
check VALNOTVALID.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
2009-06-22 14:24:30 -07:00

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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* stack_o2cb.c
*
* Code which interfaces ocfs2 with the o2cb stack.
*
* 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, version 2.
*
* 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.
*/
#include <linux/crc32.h>
#include <linux/module.h>
/* Needed for AOP_TRUNCATED_PAGE in mlog_errno() */
#include <linux/fs.h>
#include "cluster/masklog.h"
#include "cluster/nodemanager.h"
#include "cluster/heartbeat.h"
#include "stackglue.h"
struct o2dlm_private {
struct dlm_eviction_cb op_eviction_cb;
};
static struct ocfs2_stack_plugin o2cb_stack;
/* These should be identical */
#if (DLM_LOCK_IV != LKM_IVMODE)
# error Lock modes do not match
#endif
#if (DLM_LOCK_NL != LKM_NLMODE)
# error Lock modes do not match
#endif
#if (DLM_LOCK_CR != LKM_CRMODE)
# error Lock modes do not match
#endif
#if (DLM_LOCK_CW != LKM_CWMODE)
# error Lock modes do not match
#endif
#if (DLM_LOCK_PR != LKM_PRMODE)
# error Lock modes do not match
#endif
#if (DLM_LOCK_PW != LKM_PWMODE)
# error Lock modes do not match
#endif
#if (DLM_LOCK_EX != LKM_EXMODE)
# error Lock modes do not match
#endif
static inline int mode_to_o2dlm(int mode)
{
BUG_ON(mode > LKM_MAXMODE);
return mode;
}
#define map_flag(_generic, _o2dlm) \
if (flags & (_generic)) { \
flags &= ~(_generic); \
o2dlm_flags |= (_o2dlm); \
}
static int flags_to_o2dlm(u32 flags)
{
int o2dlm_flags = 0;
map_flag(DLM_LKF_NOQUEUE, LKM_NOQUEUE);
map_flag(DLM_LKF_CANCEL, LKM_CANCEL);
map_flag(DLM_LKF_CONVERT, LKM_CONVERT);
map_flag(DLM_LKF_VALBLK, LKM_VALBLK);
map_flag(DLM_LKF_IVVALBLK, LKM_INVVALBLK);
map_flag(DLM_LKF_ORPHAN, LKM_ORPHAN);
map_flag(DLM_LKF_FORCEUNLOCK, LKM_FORCE);
map_flag(DLM_LKF_TIMEOUT, LKM_TIMEOUT);
map_flag(DLM_LKF_LOCAL, LKM_LOCAL);
/* map_flag() should have cleared every flag passed in */
BUG_ON(flags != 0);
return o2dlm_flags;
}
#undef map_flag
/*
* Map an o2dlm status to standard errno values.
*
* o2dlm only uses a handful of these, and returns even fewer to the
* caller. Still, we try to assign sane values to each error.
*
* The following value pairs have special meanings to dlmglue, thus
* the right hand side needs to stay unique - never duplicate the
* mapping elsewhere in the table!
*
* DLM_NORMAL: 0
* DLM_NOTQUEUED: -EAGAIN
* DLM_CANCELGRANT: -EBUSY
* DLM_CANCEL: -DLM_ECANCEL
*/
/* Keep in sync with dlmapi.h */
static int status_map[] = {
[DLM_NORMAL] = 0, /* Success */
[DLM_GRANTED] = -EINVAL,
[DLM_DENIED] = -EACCES,
[DLM_DENIED_NOLOCKS] = -EACCES,
[DLM_WORKING] = -EACCES,
[DLM_BLOCKED] = -EINVAL,
[DLM_BLOCKED_ORPHAN] = -EINVAL,
[DLM_DENIED_GRACE_PERIOD] = -EACCES,
[DLM_SYSERR] = -ENOMEM, /* It is what it is */
[DLM_NOSUPPORT] = -EPROTO,
[DLM_CANCELGRANT] = -EBUSY, /* Cancel after grant */
[DLM_IVLOCKID] = -EINVAL,
[DLM_SYNC] = -EINVAL,
[DLM_BADTYPE] = -EINVAL,
[DLM_BADRESOURCE] = -EINVAL,
[DLM_MAXHANDLES] = -ENOMEM,
[DLM_NOCLINFO] = -EINVAL,
[DLM_NOLOCKMGR] = -EINVAL,
[DLM_NOPURGED] = -EINVAL,
[DLM_BADARGS] = -EINVAL,
[DLM_VOID] = -EINVAL,
[DLM_NOTQUEUED] = -EAGAIN, /* Trylock failed */
[DLM_IVBUFLEN] = -EINVAL,
[DLM_CVTUNGRANT] = -EPERM,
[DLM_BADPARAM] = -EINVAL,
[DLM_VALNOTVALID] = -EINVAL,
[DLM_REJECTED] = -EPERM,
[DLM_ABORT] = -EINVAL,
[DLM_CANCEL] = -DLM_ECANCEL, /* Successful cancel */
[DLM_IVRESHANDLE] = -EINVAL,
[DLM_DEADLOCK] = -EDEADLK,
[DLM_DENIED_NOASTS] = -EINVAL,
[DLM_FORWARD] = -EINVAL,
[DLM_TIMEOUT] = -ETIMEDOUT,
[DLM_IVGROUPID] = -EINVAL,
[DLM_VERS_CONFLICT] = -EOPNOTSUPP,
[DLM_BAD_DEVICE_PATH] = -ENOENT,
[DLM_NO_DEVICE_PERMISSION] = -EPERM,
[DLM_NO_CONTROL_DEVICE] = -ENOENT,
[DLM_RECOVERING] = -ENOTCONN,
[DLM_MIGRATING] = -ERESTART,
[DLM_MAXSTATS] = -EINVAL,
};
static int dlm_status_to_errno(enum dlm_status status)
{
BUG_ON(status > (sizeof(status_map) / sizeof(status_map[0])));
return status_map[status];
}
static void o2dlm_lock_ast_wrapper(void *astarg)
{
BUG_ON(o2cb_stack.sp_proto == NULL);
o2cb_stack.sp_proto->lp_lock_ast(astarg);
}
static void o2dlm_blocking_ast_wrapper(void *astarg, int level)
{
BUG_ON(o2cb_stack.sp_proto == NULL);
o2cb_stack.sp_proto->lp_blocking_ast(astarg, level);
}
static void o2dlm_unlock_ast_wrapper(void *astarg, enum dlm_status status)
{
int error = dlm_status_to_errno(status);
BUG_ON(o2cb_stack.sp_proto == NULL);
/*
* In o2dlm, you can get both the lock_ast() for the lock being
* granted and the unlock_ast() for the CANCEL failing. A
* successful cancel sends DLM_NORMAL here. If the
* lock grant happened before the cancel arrived, you get
* DLM_CANCELGRANT.
*
* There's no need for the double-ast. If we see DLM_CANCELGRANT,
* we just ignore it. We expect the lock_ast() to handle the
* granted lock.
*/
if (status == DLM_CANCELGRANT)
return;
o2cb_stack.sp_proto->lp_unlock_ast(astarg, error);
}
static int o2cb_dlm_lock(struct ocfs2_cluster_connection *conn,
int mode,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *name,
unsigned int namelen,
void *astarg)
{
enum dlm_status status;
int o2dlm_mode = mode_to_o2dlm(mode);
int o2dlm_flags = flags_to_o2dlm(flags);
int ret;
status = dlmlock(conn->cc_lockspace, o2dlm_mode, &lksb->lksb_o2dlm,
o2dlm_flags, name, namelen,
o2dlm_lock_ast_wrapper, astarg,
o2dlm_blocking_ast_wrapper);
ret = dlm_status_to_errno(status);
return ret;
}
static int o2cb_dlm_unlock(struct ocfs2_cluster_connection *conn,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *astarg)
{
enum dlm_status status;
int o2dlm_flags = flags_to_o2dlm(flags);
int ret;
status = dlmunlock(conn->cc_lockspace, &lksb->lksb_o2dlm,
o2dlm_flags, o2dlm_unlock_ast_wrapper, astarg);
ret = dlm_status_to_errno(status);
return ret;
}
static int o2cb_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
{
return dlm_status_to_errno(lksb->lksb_o2dlm.status);
}
/*
* o2dlm aways has a "valid" LVB. If the dlm loses track of the LVB
* contents, it will zero out the LVB. Thus the caller can always trust
* the contents.
*/
static int o2cb_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb)
{
return 1;
}
static void *o2cb_dlm_lvb(union ocfs2_dlm_lksb *lksb)
{
return (void *)(lksb->lksb_o2dlm.lvb);
}
static void o2cb_dump_lksb(union ocfs2_dlm_lksb *lksb)
{
dlm_print_one_lock(lksb->lksb_o2dlm.lockid);
}
/*
* Called from the dlm when it's about to evict a node. This is how the
* classic stack signals node death.
*/
static void o2dlm_eviction_cb(int node_num, void *data)
{
struct ocfs2_cluster_connection *conn = data;
mlog(ML_NOTICE, "o2dlm has evicted node %d from group %.*s\n",
node_num, conn->cc_namelen, conn->cc_name);
conn->cc_recovery_handler(node_num, conn->cc_recovery_data);
}
static int o2cb_cluster_connect(struct ocfs2_cluster_connection *conn)
{
int rc = 0;
u32 dlm_key;
struct dlm_ctxt *dlm;
struct o2dlm_private *priv;
struct dlm_protocol_version dlm_version;
BUG_ON(conn == NULL);
BUG_ON(o2cb_stack.sp_proto == NULL);
/* for now we only have one cluster/node, make sure we see it
* in the heartbeat universe */
if (!o2hb_check_local_node_heartbeating()) {
rc = -EINVAL;
goto out;
}
priv = kzalloc(sizeof(struct o2dlm_private), GFP_KERNEL);
if (!priv) {
rc = -ENOMEM;
goto out_free;
}
/* This just fills the structure in. It is safe to pass conn. */
dlm_setup_eviction_cb(&priv->op_eviction_cb, o2dlm_eviction_cb,
conn);
conn->cc_private = priv;
/* used by the dlm code to make message headers unique, each
* node in this domain must agree on this. */
dlm_key = crc32_le(0, conn->cc_name, conn->cc_namelen);
dlm_version.pv_major = conn->cc_version.pv_major;
dlm_version.pv_minor = conn->cc_version.pv_minor;
dlm = dlm_register_domain(conn->cc_name, dlm_key, &dlm_version);
if (IS_ERR(dlm)) {
rc = PTR_ERR(dlm);
mlog_errno(rc);
goto out_free;
}
conn->cc_version.pv_major = dlm_version.pv_major;
conn->cc_version.pv_minor = dlm_version.pv_minor;
conn->cc_lockspace = dlm;
dlm_register_eviction_cb(dlm, &priv->op_eviction_cb);
out_free:
if (rc && conn->cc_private)
kfree(conn->cc_private);
out:
return rc;
}
static int o2cb_cluster_disconnect(struct ocfs2_cluster_connection *conn)
{
struct dlm_ctxt *dlm = conn->cc_lockspace;
struct o2dlm_private *priv = conn->cc_private;
dlm_unregister_eviction_cb(&priv->op_eviction_cb);
conn->cc_private = NULL;
kfree(priv);
dlm_unregister_domain(dlm);
conn->cc_lockspace = NULL;
return 0;
}
static int o2cb_cluster_this_node(unsigned int *node)
{
int node_num;
node_num = o2nm_this_node();
if (node_num == O2NM_INVALID_NODE_NUM)
return -ENOENT;
if (node_num >= O2NM_MAX_NODES)
return -EOVERFLOW;
*node = node_num;
return 0;
}
static struct ocfs2_stack_operations o2cb_stack_ops = {
.connect = o2cb_cluster_connect,
.disconnect = o2cb_cluster_disconnect,
.this_node = o2cb_cluster_this_node,
.dlm_lock = o2cb_dlm_lock,
.dlm_unlock = o2cb_dlm_unlock,
.lock_status = o2cb_dlm_lock_status,
.lvb_valid = o2cb_dlm_lvb_valid,
.lock_lvb = o2cb_dlm_lvb,
.dump_lksb = o2cb_dump_lksb,
};
static struct ocfs2_stack_plugin o2cb_stack = {
.sp_name = "o2cb",
.sp_ops = &o2cb_stack_ops,
.sp_owner = THIS_MODULE,
};
static int __init o2cb_stack_init(void)
{
return ocfs2_stack_glue_register(&o2cb_stack);
}
static void __exit o2cb_stack_exit(void)
{
ocfs2_stack_glue_unregister(&o2cb_stack);
}
MODULE_AUTHOR("Oracle");
MODULE_DESCRIPTION("ocfs2 driver for the classic o2cb stack");
MODULE_LICENSE("GPL");
module_init(o2cb_stack_init);
module_exit(o2cb_stack_exit);
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