llog_cat.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>

/* Create a new log handle and add it to the open list.
 * This log handle will be closed when all of the records in it are removed.
 *
 * Assumes caller has already pushed us into the kernel context and is locking.
 */
static struct llog_handle *llog_cat_new_log(struct llog_handle *cathandle)
{
        struct llog_handle *loghandle;
        struct llog_log_hdr *llh;
        struct llog_logid_rec rec = { { 0 }, };
        int rc, index, bitmap_size;
        ENTRY;

        llh = cathandle->lgh_hdr;
        bitmap_size = LLOG_BITMAP_SIZE(llh);

        index = (cathandle->lgh_last_idx + 1) % bitmap_size;

        /* maximum number of available slots in catlog is bitmap_size - 2 */
        if (llh->llh_cat_idx == index) {
                CERROR("no free catalog slots for log...\n");
                RETURN(ERR_PTR(-ENOSPC));
        }

        if (OBD_FAIL_CHECK_ONCE(OBD_FAIL_MDS_LLOG_CREATE_FAILED))
                RETURN(ERR_PTR(-ENOSPC));
        
        rc = llog_create(cathandle->lgh_ctxt, &loghandle, NULL, NULL);
        if (rc)
                RETURN(ERR_PTR(rc));
        
        rc = llog_init_handle(loghandle,
                              LLOG_F_IS_PLAIN | LLOG_F_ZAP_WHEN_EMPTY,
                              &cathandle->lgh_hdr->llh_tgtuuid);
        if (rc)
                GOTO(out_destroy, rc);
        if (index == 0)
                index = 1;
        if (ext2_set_bit(index, llh->llh_bitmap)) {
                CERROR("argh, index %u already set in log bitmap?\n",
                       index);
                LBUG(); /* should never happen */
        }
        cathandle->lgh_last_idx = index;
        llh->llh_count++;
        llh->llh_tail.lrt_index = index;

        CDEBUG(D_RPCTRACE,"new recovery log "LPX64":%x for index %u of catalog "
               LPX64"\n", loghandle->lgh_id.lgl_oid, loghandle->lgh_id.lgl_ogen,
               index, cathandle->lgh_id.lgl_oid);
        /* build the record for this log in the catalog */
        rec.lid_hdr.lrh_len = sizeof(rec);
        rec.lid_hdr.lrh_index = index;
        rec.lid_hdr.lrh_type = LLOG_LOGID_MAGIC;
        rec.lid_id = loghandle->lgh_id;
        rec.lid_tail.lrt_len = sizeof(rec);
        rec.lid_tail.lrt_index = index;

        /* update the catalog: header and record */
        rc = llog_write_rec(cathandle, &rec.lid_hdr,
                            &loghandle->u.phd.phd_cookie, 1, NULL, index);
        if (rc < 0) {
                GOTO(out_destroy, rc);
        }

        loghandle->lgh_hdr->llh_cat_idx = index;
        cathandle->u.chd.chd_current_log = loghandle;
        LASSERT(list_empty(&loghandle->u.phd.phd_entry));
        list_add_tail(&loghandle->u.phd.phd_entry, &cathandle->u.chd.chd_head);

 out_destroy:
        if (rc < 0)
                llog_destroy(loghandle);

        RETURN(loghandle);
}
EXPORT_SYMBOL(llog_cat_new_log);

/* Open an existent log handle and add it to the open list.
 * This log handle will be closed when all of the records in it are removed.
 *
 * Assumes caller has already pushed us into the kernel context and is locking.
 * We return a lock on the handle to ensure nobody yanks it from us.
 */
int llog_cat_id2handle(struct llog_handle *cathandle, struct llog_handle **res,
                       struct llog_logid *logid)
{
        struct llog_handle *loghandle;
        int rc = 0;
        ENTRY;

        if (cathandle == NULL)
                RETURN(-EBADF);

        list_for_each_entry(loghandle, &cathandle->u.chd.chd_head,
                            u.phd.phd_entry) {
                struct llog_logid *cgl = &loghandle->lgh_id;
                if (cgl->lgl_oid == logid->lgl_oid) {
                        if (cgl->lgl_ogen != logid->lgl_ogen) {
                                CERROR("log "LPX64" generation %x != %x\n",
                                       logid->lgl_oid, cgl->lgl_ogen,
                                       logid->lgl_ogen);
                                continue;
                        }
                        loghandle->u.phd.phd_cat_handle = cathandle;
                        GOTO(out, rc = 0);
                }
        }

        rc = llog_create(cathandle->lgh_ctxt, &loghandle, logid, NULL);
        if (rc) {
                CERROR("error opening log id "LPX64":%x: rc %d\n",
                       logid->lgl_oid, logid->lgl_ogen, rc);
        } else {
                rc = llog_init_handle(loghandle, LLOG_F_IS_PLAIN, NULL);
                if (!rc) {
                        list_add(&loghandle->u.phd.phd_entry,
                                 &cathandle->u.chd.chd_head);
                }
        }
        if (!rc) {
                loghandle->u.phd.phd_cat_handle = cathandle;
                loghandle->u.phd.phd_cookie.lgc_lgl = cathandle->lgh_id;
                loghandle->u.phd.phd_cookie.lgc_index = 
                        loghandle->lgh_hdr->llh_cat_idx;
        }

out:
        *res = loghandle;
        RETURN(rc);
}

int llog_cat_put(struct llog_handle *cathandle)
{
        struct llog_handle *loghandle, *n;
        int rc;
        ENTRY;

        list_for_each_entry_safe(loghandle, n, &cathandle->u.chd.chd_head,
                                 u.phd.phd_entry) {
                int err = llog_close(loghandle);
                if (err)
                        CERROR("error closing loghandle\n");
        }
        rc = llog_close(cathandle);
        RETURN(rc);
}
EXPORT_SYMBOL(llog_cat_put);

/* Return the currently active log handle.  If the current log handle doesn't
 * have enough space left for the current record, start a new one.
 *
 * If reclen is 0, we only want to know what the currently active log is,
 * otherwise we get a lock on this log so nobody can steal our space.
 *
 * Assumes caller has already pushed us into the kernel context and is locking.
 *
 * NOTE: loghandle is write-locked upon successful return
 */
static struct llog_handle *llog_cat_current_log(struct llog_handle *cathandle,
                                                int create)
{
        struct llog_handle *loghandle = NULL;
        ENTRY;

        down_read(&cathandle->lgh_lock);
        loghandle = cathandle->u.chd.chd_current_log;
        if (loghandle) {
                struct llog_log_hdr *llh = loghandle->lgh_hdr;
                down_write(&loghandle->lgh_lock);
                if (loghandle->lgh_last_idx < LLOG_BITMAP_SIZE(llh) - 1) {
                        up_read(&cathandle->lgh_lock);
                        RETURN(loghandle);
                } else {
                        up_write(&loghandle->lgh_lock);
                }
        }
        if (!create) {
                if (loghandle)
                        down_write(&loghandle->lgh_lock);
                up_read(&cathandle->lgh_lock);
                RETURN(loghandle);
        }
        up_read(&cathandle->lgh_lock);

        /* time to create new log */

        /* first, we have to make sure the state hasn't changed */
        down_write(&cathandle->lgh_lock);
        loghandle = cathandle->u.chd.chd_current_log;
        if (loghandle) {
                struct llog_log_hdr *llh = loghandle->lgh_hdr;
                down_write(&loghandle->lgh_lock);
                if (loghandle->lgh_last_idx < LLOG_BITMAP_SIZE(llh) - 1) {
                        up_write(&cathandle->lgh_lock);
                        RETURN(loghandle);
                } else {
                        up_write(&loghandle->lgh_lock);
                }
        }

        CDEBUG(D_INODE, "creating new log\n");
        loghandle = llog_cat_new_log(cathandle);
        if (!IS_ERR(loghandle))
                down_write(&loghandle->lgh_lock);
        up_write(&cathandle->lgh_lock);
        RETURN(loghandle);
}

/* Add a single record to the recovery log(s) using a catalog
 * Returns as llog_write_record
 *
 * Assumes caller has already pushed us into the kernel context.
 */
int llog_cat_add_rec(struct llog_handle *cathandle, struct llog_rec_hdr *rec,
                     struct llog_cookie *reccookie, void *buf)
{
        struct llog_handle *loghandle;
        int rc;
        ENTRY;

        LASSERT(rec->lrh_len <= LLOG_CHUNK_SIZE);
        loghandle = llog_cat_current_log(cathandle, 1);
        if (IS_ERR(loghandle))
                RETURN(PTR_ERR(loghandle));