dlmglue.c

linux 内核源代码

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmglue.c
 *
 * Code which implements an OCFS2 specific interface to our DLM.
 *
 * Copyright (C) 2003, 2004 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; either
 * version 2 of the License, or (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/crc32.h>
#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>

#include <cluster/heartbeat.h>
#include <cluster/nodemanager.h>
#include <cluster/tcp.h>

#include <dlm/dlmapi.h>

#define MLOG_MASK_PREFIX ML_DLM_GLUE
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dcache.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "file.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "slot_map.h"
#include "super.h"
#include "uptodate.h"
#include "vote.h"

#include "buffer_head_io.h"

struct ocfs2_mask_waiter {
	struct list_head	mw_item;
	int			mw_status;
	struct completion	mw_complete;
	unsigned long		mw_mask;
	unsigned long		mw_goal;
};

static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres);
static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres);

/*
 * Return value from ->downconvert_worker functions.
 *
 * These control the precise actions of ocfs2_unblock_lock()
 * and ocfs2_process_blocked_lock()
 *
 */
enum ocfs2_unblock_action {
	UNBLOCK_CONTINUE	= 0, /* Continue downconvert */
	UNBLOCK_CONTINUE_POST	= 1, /* Continue downconvert, fire
				      * ->post_unlock callback */
	UNBLOCK_STOP_POST	= 2, /* Do not downconvert, fire
				      * ->post_unlock() callback. */
};

struct ocfs2_unblock_ctl {
	int requeue;
	enum ocfs2_unblock_action unblock_action;
};

static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
					int new_level);
static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres);

static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
				     int blocking);

static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
				       int blocking);

static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
				     struct ocfs2_lock_res *lockres);


#define mlog_meta_lvb(__level, __lockres) ocfs2_dump_meta_lvb_info(__level, __PRETTY_FUNCTION__, __LINE__, __lockres)

/* This aids in debugging situations where a bad LVB might be involved. */
static void ocfs2_dump_meta_lvb_info(u64 level,
				     const char *function,
				     unsigned int line,
				     struct ocfs2_lock_res *lockres)
{
	struct ocfs2_meta_lvb *lvb = (struct ocfs2_meta_lvb *) lockres->l_lksb.lvb;

	mlog(level, "LVB information for %s (called from %s:%u):\n",
	     lockres->l_name, function, line);
	mlog(level, "version: %u, clusters: %u, generation: 0x%x\n",
	     lvb->lvb_version, be32_to_cpu(lvb->lvb_iclusters),
	     be32_to_cpu(lvb->lvb_igeneration));
	mlog(level, "size: %llu, uid %u, gid %u, mode 0x%x\n",
	     (unsigned long long)be64_to_cpu(lvb->lvb_isize),
	     be32_to_cpu(lvb->lvb_iuid), be32_to_cpu(lvb->lvb_igid),
	     be16_to_cpu(lvb->lvb_imode));
	mlog(level, "nlink %u, atime_packed 0x%llx, ctime_packed 0x%llx, "
	     "mtime_packed 0x%llx iattr 0x%x\n", be16_to_cpu(lvb->lvb_inlink),
	     (long long)be64_to_cpu(lvb->lvb_iatime_packed),
	     (long long)be64_to_cpu(lvb->lvb_ictime_packed),
	     (long long)be64_to_cpu(lvb->lvb_imtime_packed),
	     be32_to_cpu(lvb->lvb_iattr));
}


/*
 * OCFS2 Lock Resource Operations
 *
 * These fine tune the behavior of the generic dlmglue locking infrastructure.
 *
 * The most basic of lock types can point ->l_priv to their respective
 * struct ocfs2_super and allow the default actions to manage things.
 *
 * Right now, each lock type also needs to implement an init function,
 * and trivial lock/unlock wrappers. ocfs2_simple_drop_lockres()
 * should be called when the lock is no longer needed (i.e., object
 * destruction time).
 */
struct ocfs2_lock_res_ops {
	/*
	 * Translate an ocfs2_lock_res * into an ocfs2_super *. Define
	 * this callback if ->l_priv is not an ocfs2_super pointer
	 */
	struct ocfs2_super * (*get_osb)(struct ocfs2_lock_res *);

	/*
	 * Optionally called in the downconvert (or "vote") thread
	 * after a successful downconvert. The lockres will not be
	 * referenced after this callback is called, so it is safe to
	 * free memory, etc.
	 *
	 * The exact semantics of when this is called are controlled
	 * by ->downconvert_worker()
	 */
	void (*post_unlock)(struct ocfs2_super *, struct ocfs2_lock_res *);

	/*
	 * Allow a lock type to add checks to determine whether it is
	 * safe to downconvert a lock. Return 0 to re-queue the
	 * downconvert at a later time, nonzero to continue.
	 *
	 * For most locks, the default checks that there are no
	 * incompatible holders are sufficient.
	 *
	 * Called with the lockres spinlock held.
	 */
	int (*check_downconvert)(struct ocfs2_lock_res *, int);

	/*
	 * Allows a lock type to populate the lock value block. This
	 * is called on downconvert, and when we drop a lock.
	 *
	 * Locks that want to use this should set LOCK_TYPE_USES_LVB
	 * in the flags field.
	 *
	 * Called with the lockres spinlock held.
	 */
	void (*set_lvb)(struct ocfs2_lock_res *);

	/*
	 * Called from the downconvert thread when it is determined
	 * that a lock will be downconverted. This is called without
	 * any locks held so the function can do work that might
	 * schedule (syncing out data, etc).
	 *
	 * This should return any one of the ocfs2_unblock_action
	 * values, depending on what it wants the thread to do.
	 */
	int (*downconvert_worker)(struct ocfs2_lock_res *, int);

	/*
	 * LOCK_TYPE_* flags which describe the specific requirements
	 * of a lock type. Descriptions of each individual flag follow.
	 */
	int flags;
};

/*
 * Some locks want to "refresh" potentially stale data when a
 * meaningful (PRMODE or EXMODE) lock level is first obtained. If this
 * flag is set, the OCFS2_LOCK_NEEDS_REFRESH flag will be set on the
 * individual lockres l_flags member from the ast function. It is
 * expected that the locking wrapper will clear the
 * OCFS2_LOCK_NEEDS_REFRESH flag when done.
 */
#define LOCK_TYPE_REQUIRES_REFRESH 0x1

/*
 * Indicate that a lock type makes use of the lock value block. The
 * ->set_lvb lock type callback must be defined.
 */
#define LOCK_TYPE_USES_LVB		0x2

static struct ocfs2_lock_res_ops ocfs2_inode_rw_lops = {
	.get_osb	= ocfs2_get_inode_osb,
	.flags		= 0,
};

static struct ocfs2_lock_res_ops ocfs2_inode_meta_lops = {
	.get_osb	= ocfs2_get_inode_osb,
	.check_downconvert = ocfs2_check_meta_downconvert,
	.set_lvb	= ocfs2_set_meta_lvb,
	.flags		= LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
};

static struct ocfs2_lock_res_ops ocfs2_inode_data_lops = {
	.get_osb	= ocfs2_get_inode_osb,
	.downconvert_worker = ocfs2_data_convert_worker,
	.flags		= 0,
};

static struct ocfs2_lock_res_ops ocfs2_super_lops = {
	.flags		= LOCK_TYPE_REQUIRES_REFRESH,
};

static struct ocfs2_lock_res_ops ocfs2_rename_lops = {
	.flags		= 0,
};

static struct ocfs2_lock_res_ops ocfs2_dentry_lops = {
	.get_osb	= ocfs2_get_dentry_osb,
	.post_unlock	= ocfs2_dentry_post_unlock,
	.downconvert_worker = ocfs2_dentry_convert_worker,
	.flags		= 0,
};

static struct ocfs2_lock_res_ops ocfs2_inode_open_lops = {
	.get_osb	= ocfs2_get_inode_osb,
	.flags		= 0,
};

static inline int ocfs2_is_inode_lock(struct ocfs2_lock_res *lockres)
{
	return lockres->l_type == OCFS2_LOCK_TYPE_META ||
		lockres->l_type == OCFS2_LOCK_TYPE_DATA ||
		lockres->l_type == OCFS2_LOCK_TYPE_RW ||
		lockres->l_type == OCFS2_LOCK_TYPE_OPEN;
}

static inline struct inode *ocfs2_lock_res_inode(struct ocfs2_lock_res *lockres)
{
	BUG_ON(!ocfs2_is_inode_lock(lockres));

	return (struct inode *) lockres->l_priv;
}

static inline struct ocfs2_dentry_lock *ocfs2_lock_res_dl(struct ocfs2_lock_res *lockres)
{
	BUG_ON(lockres->l_type != OCFS2_LOCK_TYPE_DENTRY);

	return (struct ocfs2_dentry_lock *)lockres->l_priv;
}

static inline struct ocfs2_super *ocfs2_get_lockres_osb(struct ocfs2_lock_res *lockres)
{
	if (lockres->l_ops->get_osb)
		return lockres->l_ops->get_osb(lockres);

	return (struct ocfs2_super *)lockres->l_priv;
}

static int ocfs2_lock_create(struct ocfs2_super *osb,
			     struct ocfs2_lock_res *lockres,
			     int level,
			     int dlm_flags);
static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
						     int wanted);
static void ocfs2_cluster_unlock(struct ocfs2_super *osb,
				 struct ocfs2_lock_res *lockres,
				 int level);
static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres);
static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres);
static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres);
static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres, int level);
static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
					struct ocfs2_lock_res *lockres);
static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
						int convert);
#define ocfs2_log_dlm_error(_func, _stat, _lockres) do {	\
	mlog(ML_ERROR, "Dlm error \"%s\" while calling %s on "	\
		"resource %s: %s\n", dlm_errname(_stat), _func,	\
		_lockres->l_name, dlm_errmsg(_stat));		\
} while (0)
static void ocfs2_vote_on_unlock(struct ocfs2_super *osb,
				 struct ocfs2_lock_res *lockres);
static int ocfs2_meta_lock_update(struct inode *inode,
				  struct buffer_head **bh);
static void ocfs2_drop_osb_locks(struct ocfs2_super *osb);
static inline int ocfs2_highest_compat_lock_level(int level);

static void ocfs2_build_lock_name(enum ocfs2_lock_type type,
				  u64 blkno,
				  u32 generation,
				  char *name)
{
	int len;

	mlog_entry_void();

	BUG_ON(type >= OCFS2_NUM_LOCK_TYPES);

	len = snprintf(name, OCFS2_LOCK_ID_MAX_LEN, "%c%s%016llx%08x",
		       ocfs2_lock_type_char(type), OCFS2_LOCK_ID_PAD,
		       (long long)blkno, generation);

	BUG_ON(len != (OCFS2_LOCK_ID_MAX_LEN - 1));

	mlog(0, "built lock resource with name: %s\n", name);

	mlog_exit_void();
}

static DEFINE_SPINLOCK(ocfs2_dlm_tracking_lock);

static void ocfs2_add_lockres_tracking(struct ocfs2_lock_res *res,
				       struct ocfs2_dlm_debug *dlm_debug)
{
	mlog(0, "Add tracking for lockres %s\n", res->l_name);

	spin_lock(&ocfs2_dlm_tracking_lock);
	list_add(&res->l_debug_list, &dlm_debug->d_lockres_tracking);
	spin_unlock(&ocfs2_dlm_tracking_lock);
}

static void ocfs2_remove_lockres_tracking(struct ocfs2_lock_res *res)
{
	spin_lock(&ocfs2_dlm_tracking_lock);
	if (!list_empty(&res->l_debug_list))
		list_del_init(&res->l_debug_list);
	spin_unlock(&ocfs2_dlm_tracking_lock);
}

static void ocfs2_lock_res_init_common(struct ocfs2_super *osb,
				       struct ocfs2_lock_res *res,
				       enum ocfs2_lock_type type,
				       struct ocfs2_lock_res_ops *ops,
				       void *priv)
{
	res->l_type          = type;
	res->l_ops           = ops;
	res->l_priv          = priv;

	res->l_level         = LKM_IVMODE;
	res->l_requested     = LKM_IVMODE;
	res->l_blocking      = LKM_IVMODE;
	res->l_action        = OCFS2_AST_INVALID;
	res->l_unlock_action = OCFS2_UNLOCK_INVALID;

	res->l_flags         = OCFS2_LOCK_INITIALIZED;

	ocfs2_add_lockres_tracking(res, osb->osb_dlm_debug);
}

void ocfs2_lock_res_init_once(struct ocfs2_lock_res *res)
{
	/* This also clears out the lock status block */
	memset(res, 0, sizeof(struct ocfs2_lock_res));
	spin_lock_init(&res->l_lock);
	init_waitqueue_head(&res->l_event);
	INIT_LIST_HEAD(&res->l_blocked_list);
	INIT_LIST_HEAD(&res->l_mask_waiters);
}

void ocfs2_inode_lock_res_init(struct ocfs2_lock_res *res,
			       enum ocfs2_lock_type type,
			       unsigned int generation,
			       struct inode *inode)
{
	struct ocfs2_lock_res_ops *ops;

	switch(type) {
		case OCFS2_LOCK_TYPE_RW:
			ops = &ocfs2_inode_rw_lops;
			break;
		case OCFS2_LOCK_TYPE_META:
			ops = &ocfs2_inode_meta_lops;
			break;
		case OCFS2_LOCK_TYPE_DATA:
			ops = &ocfs2_inode_data_lops;
			break;
		case OCFS2_LOCK_TYPE_OPEN:
			ops = &ocfs2_inode_open_lops;
			break;
		default:
			mlog_bug_on_msg(1, "type: %d\n", type);
			ops = NULL; /* thanks, gcc */
			break;
	};

	ocfs2_build_lock_name(type, OCFS2_I(inode)->ip_blkno,
			      generation, res->l_name);
	ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), res, type, ops, inode);
}

static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres)
{
	struct inode *inode = ocfs2_lock_res_inode(lockres);

	return OCFS2_SB(inode->i_sb);
}

static __u64 ocfs2_get_dentry_lock_ino(struct ocfs2_lock_res *lockres)
{
	__be64 inode_blkno_be;

	memcpy(&inode_blkno_be, &lockres->l_name[OCFS2_DENTRY_LOCK_INO_START],
	       sizeof(__be64));

	return be64_to_cpu(inode_blkno_be);
}

static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres)
{
	struct ocfs2_dentry_lock *dl = lockres->l_priv;

	return OCFS2_SB(dl->dl_inode->i_sb);
}

void ocfs2_dentry_lock_res_init(struct ocfs2_dentry_lock *dl,
				u64 parent, struct inode *inode)
{
	int len;
	u64 inode_blkno = OCFS2_I(inode)->ip_blkno;
	__be64 inode_blkno_be = cpu_to_be64(inode_blkno);
	struct ocfs2_lock_res *lockres = &dl->dl_lockres;

	ocfs2_lock_res_init_once(lockres);

	/*
	 * Unfortunately, the standard lock naming scheme won't work
	 * here because we have two 16 byte values to use. Instead,
	 * we'll stuff the inode number as a binary value. We still
	 * want error prints to show something without garbling the
	 * display, so drop a null byte in there before the inode
	 * number. A future version of OCFS2 will likely use all
	 * binary lock names. The stringified names have been a
	 * tremendous aid in debugging, but now that the debugfs
	 * interface exists, we can mangle things there if need be.
	 *
	 * NOTE: We also drop the standard "pad" value (the total lock
	 * name size stays the same though - the last part is all
	 * zeros due to the memset in ocfs2_lock_res_init_once()
	 */
	len = snprintf(lockres->l_name, OCFS2_DENTRY_LOCK_INO_START,
		       "%c%016llx",
		       ocfs2_lock_type_char(OCFS2_LOCK_TYPE_DENTRY),
		       (long long)parent);

	BUG_ON(len != (OCFS2_DENTRY_LOCK_INO_START - 1));

	memcpy(&lockres->l_name[OCFS2_DENTRY_LOCK_INO_START], &inode_blkno_be,
	       sizeof(__be64));

	ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
				   OCFS2_LOCK_TYPE_DENTRY, &ocfs2_dentry_lops,
				   dl);
}

static void ocfs2_super_lock_res_init(struct ocfs2_lock_res *res,
				      struct ocfs2_super *osb)
{
	/* Superblock lockres doesn't come from a slab so we call init