stack_o2cb.c

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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/kernel.h>
#include <linux/crc32.h>
#include <linux/slab.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 "cluster/tcp.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 < 0 || status >= ARRAY_SIZE(status_map));

    return status_map[status];
}

static void o2dlm_lock_ast_wrapper(void *astarg)
{
    struct ocfs2_dlm_lksb *lksb = astarg;

    lksb->lksb_conn->cc_proto->lp_lock_ast(lksb);
}

static void o2dlm_blocking_ast_wrapper(void *astarg, int level)
{
    struct ocfs2_dlm_lksb *lksb = astarg;

    lksb->lksb_conn->cc_proto->lp_blocking_ast(lksb, level);
}

static void o2dlm_unlock_ast_wrapper(void *astarg, enum dlm_status status)
{
    struct ocfs2_dlm_lksb *lksb = astarg;
    int error = dlm_status_to_errno(status);

    /*
     * 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;

    lksb->lksb_conn->cc_proto->lp_unlock_ast(lksb, error);
}

static int o2cb_dlm_lock(struct ocfs2_cluster_connection *conn,
             int mode,
             struct ocfs2_dlm_lksb *lksb,
             u32 flags,
             void *name,
             unsigned int namelen)
{
    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, lksb,
             o2dlm_blocking_ast_wrapper);
    ret = dlm_status_to_errno(status);
    return ret;
}

static int o2cb_dlm_unlock(struct ocfs2_cluster_connection *conn,
               struct ocfs2_dlm_lksb *lksb,
               u32 flags)
{
    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, lksb);
    ret = dlm_status_to_errno(status);
    return ret;
}

static int o2cb_dlm_lock_status(struct 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(struct ocfs2_dlm_lksb *lksb)
{
    return 1;
}

static void *o2cb_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
{
    return (void *)(lksb->lksb_o2dlm.lvb);
}

static void o2cb_dump_lksb(struct ocfs2_dlm_lksb *lksb)
{
    dlm_print_one_lock(lksb->lksb_o2dlm.lockid);
}

/*
 * Check if this node is heartbeating and is connected to all other
 * heartbeating nodes.
 */
static int o2cb_cluster_check(void)
{
    u8 node_num;
    int i;
    unsigned long hbmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
    unsigned long netmap[BITS_TO_LONGS(O2NM_MAX_NODES)];

    node_num = o2nm_this_node();
    if (node_num == O2NM_MAX_NODES) {
        printk(KERN_ERR "o2cb: This node has not been configured.\n");
        return -EINVAL;
    }

    /*
     * o2dlm expects o2net sockets to be created. If not, then
     * dlm_join_domain() fails with a stack of errors which are both cryptic
     * and incomplete. The idea here is to detect upfront whether we have
     * managed to connect to all nodes or not. If not, then list the nodes
     * to allow the user to check the configuration (incorrect IP, firewall,
     * etc.) Yes, this is racy. But its not the end of the world.
     */
#define O2CB_MAP_STABILIZE_COUNT    60
    for (i = 0; i < O2CB_MAP_STABILIZE_COUNT; ++i) {
        o2hb_fill_node_map(hbmap, sizeof(hbmap));
        if (!test_bit(node_num, hbmap)) {
            printk(KERN_ERR "o2cb: %s heartbeat has not been "
                   "started.\n", (o2hb_global_heartbeat_active() ?
                          "Global" : "Local"));
            return -EINVAL;
        }
        o2net_fill_node_map(netmap, sizeof(netmap));
        /* Force set the current node to allow easy compare */
        set_bit(node_num, netmap);
        if (!memcmp(hbmap, netmap, sizeof(hbmap)))
            return 0;
        if (i < O2CB_MAP_STABILIZE_COUNT)
            msleep(1000);
    }

    printk(KERN_ERR "o2cb: This node could not connect to nodes:");
    i = -1;
    while ((i = find_next_bit(hbmap, O2NM_MAX_NODES,
                  i + 1)) < O2NM_MAX_NODES) {
        if (!test_bit(i, netmap))
            printk(" %u", i);
    }
    printk(".\n");

    return -ENOTCONN;
}

/*
 * 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;

    printk(KERN_NOTICE "o2cb: o2dlm has evicted node %d from domain %.*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 fs_version;

    BUG_ON(conn == NULL);
    BUG_ON(conn->cc_proto == NULL);

    /* Ensure cluster stack is up and all nodes are connected */
    rc = o2cb_cluster_check();
    if (rc) {
        printk(KERN_ERR "o2cb: Cluster check failed. Fix errors "
               "before retrying.\n");
        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);
    fs_version.pv_major = conn->cc_version.pv_major;
    fs_version.pv_minor = conn->cc_version.pv_minor;

    dlm = dlm_register_domain(conn->cc_name, dlm_key, &fs_version);
    if (IS_ERR(dlm)) {
        rc = PTR_ERR(dlm);
        mlog_errno(rc);
        goto out_free;
    }

    conn->cc_version.pv_major = fs_version.pv_major;
    conn->cc_version.pv_minor = fs_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);