llog.c

lustre 1.6.5 source code

/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  Copyright (C) 2001-2003 Cluster File Systems, Inc.
 *   Author: Andreas Dilger <[e-mail]>
 *
 *   This file is part of the Lustre file system, http://www.lustre.org
 *   Lustre is a trademark of Cluster File Systems, Inc.
 *
 *   You may have signed or agreed to another license before downloading
 *   this software.  If so, you are bound by the terms and conditions
 *   of that agreement, and the following does not apply to you.  See the
 *   LICENSE file included with this distribution for more information.
 *
 *   If you did not agree to a different license, then this copy of Lustre
 *   is open source software; you can redistribute it and/or modify it
 *   under the terms of version 2 of the GNU General Public License as
 *   published by the Free Software Foundation.
 *
 *   In either case, Lustre 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
 *   license text for more details.
 *
 * OST<->MDS recovery logging infrastructure.
 *
 * Invariants in implementation:
 * - we do not share logs among different OST<->MDS connections, so that
 *   if an OST or MDS fails it need only look at log(s) relevant to itself
 */

#define DEBUG_SUBSYSTEM S_LOG

#ifndef EXPORT_SYMTAB
#define EXPORT_SYMTAB
#endif

#ifndef __KERNEL__
#include <liblustre.h>
#endif

#include <obd_class.h>
#include <lustre_log.h>
#include <libcfs/list.h>

/* Allocate a new log or catalog handle */
struct llog_handle *llog_alloc_handle(void)
{
        struct llog_handle *loghandle;
        ENTRY;

        OBD_ALLOC(loghandle, sizeof(*loghandle));
        if (loghandle == NULL)
                RETURN(ERR_PTR(-ENOMEM));

        init_rwsem(&loghandle->lgh_lock);

        RETURN(loghandle);
}
EXPORT_SYMBOL(llog_alloc_handle);


void llog_free_handle(struct llog_handle *loghandle)
{
        if (!loghandle)
                return;

        if (!loghandle->lgh_hdr)
                goto out;
        if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_PLAIN)
                list_del_init(&loghandle->u.phd.phd_entry);
        if (loghandle->lgh_hdr->llh_flags & LLOG_F_IS_CAT)
                LASSERT(list_empty(&loghandle->u.chd.chd_head));
        OBD_FREE(loghandle->lgh_hdr, LLOG_CHUNK_SIZE);

 out:
        OBD_FREE(loghandle, sizeof(*loghandle));
}
EXPORT_SYMBOL(llog_free_handle);

/* returns negative on error; 0 if success; 1 if success & log destroyed */
int llog_cancel_rec(struct llog_handle *loghandle, int index)
{
        struct llog_log_hdr *llh = loghandle->lgh_hdr;
        int rc = 0;
        ENTRY;

        CDEBUG(D_RPCTRACE, "canceling %d in log "LPX64"\n",
               index, loghandle->lgh_id.lgl_oid);

        if (index == 0) {
                CERROR("cannot cancel index 0 (which is header)\n");
                RETURN(-EINVAL);
        }

        if (!ext2_clear_bit(index, llh->llh_bitmap)) {
                CDEBUG(D_RPCTRACE, "catalog index %u already clear?\n", index);
                RETURN(-EINVAL);
        }

        llh->llh_count--;

        if ((llh->llh_flags & LLOG_F_ZAP_WHEN_EMPTY) &&
            (llh->llh_count == 1) &&
            (loghandle->lgh_last_idx == (LLOG_BITMAP_BYTES * 8) - 1)) {
                rc = llog_destroy(loghandle);
                if (rc) {
                        CERROR("failure destroying log after last cancel: %d\n",
                               rc);
                        ext2_set_bit(index, llh->llh_bitmap);
                        llh->llh_count++;
                } else {
                        rc = 1;
                }
                RETURN(rc);
        }

        rc = llog_write_rec(loghandle, &llh->llh_hdr, NULL, 0, NULL, 0);
        if (rc) {
                CERROR("failure re-writing header %d\n", rc);
                ext2_set_bit(index, llh->llh_bitmap);
                llh->llh_count++;
        }
        RETURN(rc);
}
EXPORT_SYMBOL(llog_cancel_rec);

int llog_init_handle(struct llog_handle *handle, int flags,
                     struct obd_uuid *uuid)
{
        int rc;
        struct llog_log_hdr *llh;
        ENTRY;
        LASSERT(handle->lgh_hdr == NULL);

        OBD_ALLOC(llh, sizeof(*llh));
        if (llh == NULL)
                RETURN(-ENOMEM);
        handle->lgh_hdr = llh;
        /* first assign flags to use llog_client_ops */
        llh->llh_flags = flags;
        rc = llog_read_header(handle);
        if (rc == 0) {
                flags = llh->llh_flags;
                if (uuid && !obd_uuid_equals(uuid, &llh->llh_tgtuuid)) {
                        CERROR("uuid mismatch: %s/%s\n", (char *)uuid->uuid,
                               (char *)llh->llh_tgtuuid.uuid);
                        rc = -EEXIST;
                }
                GOTO(out, rc);
        } else if (rc != LLOG_EEMPTY || !flags) {
                /* set a pesudo flag for initialization */
                flags = LLOG_F_IS_CAT;
                GOTO(out, rc);
        }
        rc = 0;

        handle->lgh_last_idx = 0; /* header is record with index 0 */
        llh->llh_count = 1;         /* for the header record */
        llh->llh_hdr.lrh_type = LLOG_HDR_MAGIC;
        llh->llh_hdr.lrh_len = llh->llh_tail.lrt_len = LLOG_CHUNK_SIZE;
        llh->llh_hdr.lrh_index = llh->llh_tail.lrt_index = 0;
        llh->llh_timestamp = CURRENT_SECONDS;
        if (uuid)
                memcpy(&llh->llh_tgtuuid, uuid, sizeof(llh->llh_tgtuuid));
        llh->llh_bitmap_offset = offsetof(typeof(*llh),llh_bitmap);
        ext2_set_bit(0, llh->llh_bitmap);

out:
        if (flags & LLOG_F_IS_CAT) {
                CFS_INIT_LIST_HEAD(&handle->u.chd.chd_head);
                llh->llh_size = sizeof(struct llog_logid_rec);
        } else if (flags & LLOG_F_IS_PLAIN) {
                CFS_INIT_LIST_HEAD(&handle->u.phd.phd_entry);
        } else {
                CERROR("Unknown flags: %#x (Expected %#x or %#x\n",
                       flags, LLOG_F_IS_CAT, LLOG_F_IS_PLAIN);
                LBUG();
        }

        if (rc) {
                OBD_FREE(llh, sizeof(*llh));
                handle->lgh_hdr = NULL;
        }
        RETURN(rc);
}
EXPORT_SYMBOL(llog_init_handle);

int llog_close(struct llog_handle *loghandle)
{
        struct llog_operations *lop;
        int rc;
        ENTRY;

        rc = llog_handle2ops(loghandle, &lop);
        if (rc)
                GOTO(out, rc);
        if (lop->lop_close == NULL)
                GOTO(out, -EOPNOTSUPP);
        rc = lop->lop_close(loghandle);
 out:
        llog_free_handle(loghandle);
        RETURN(rc);
}
EXPORT_SYMBOL(llog_close);

int llog_process(struct llog_handle *loghandle, llog_cb_t cb,
                 void *data, void *catdata)
{
        struct llog_log_hdr *llh = loghandle->lgh_hdr;
        struct llog_process_cat_data *cd = catdata;
        char *buf;
        __u64 cur_offset = LLOG_CHUNK_SIZE, last_offset;