reservations.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * reservations.c
 *
 * Allocation reservations implementation
 *
 * Some code borrowed from fs/ext3/balloc.c and is:
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 * The rest is copyright (C) 2010 Novell.  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 version 2 as published by the Free Software Foundation.
 *
 * 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/fs.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/bitops.h>
#include <linux/list.h>

#include <cluster/masklog.h>

#include "ocfs2.h"
#include "ocfs2_trace.h"

#ifdef CONFIG_OCFS2_DEBUG_FS
#define OCFS2_CHECK_RESERVATIONS
#endif

DEFINE_SPINLOCK(resv_lock);

#define OCFS2_MIN_RESV_WINDOW_BITS  8
#define OCFS2_MAX_RESV_WINDOW_BITS  1024

int ocfs2_dir_resv_allowed(struct ocfs2_super *osb)
{
    return (osb->osb_resv_level && osb->osb_dir_resv_level);
}

static unsigned int ocfs2_resv_window_bits(struct ocfs2_reservation_map *resmap,
                       struct ocfs2_alloc_reservation *resv)
{
    struct ocfs2_super *osb = resmap->m_osb;
    unsigned int bits;

    if (!(resv->r_flags & OCFS2_RESV_FLAG_DIR)) {
        /* 8, 16, 32, 64, 128, 256, 512, 1024 */
        bits = 4 << osb->osb_resv_level;
    } else {
        bits = 4 << osb->osb_dir_resv_level;
    }
    return bits;
}

static inline unsigned int ocfs2_resv_end(struct ocfs2_alloc_reservation *resv)
{
    if (resv->r_len)
        return resv->r_start + resv->r_len - 1;
    return resv->r_start;
}

static inline int ocfs2_resv_empty(struct ocfs2_alloc_reservation *resv)
{
    return !!(resv->r_len == 0);
}

static inline int ocfs2_resmap_disabled(struct ocfs2_reservation_map *resmap)
{
    if (resmap->m_osb->osb_resv_level == 0)
        return 1;
    return 0;
}

static void ocfs2_dump_resv(struct ocfs2_reservation_map *resmap)
{
    struct ocfs2_super *osb = resmap->m_osb;
    struct rb_node *node;
    struct ocfs2_alloc_reservation *resv;
    int i = 0;

    mlog(ML_NOTICE, "Dumping resmap for device %s. Bitmap length: %u\n",
         osb->dev_str, resmap->m_bitmap_len);

    node = rb_first(&resmap->m_reservations);
    while (node) {
        resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);

        mlog(ML_NOTICE, "start: %u\tend: %u\tlen: %u\tlast_start: %u"
             "\tlast_len: %u\n", resv->r_start,
             ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
             resv->r_last_len);

        node = rb_next(node);
        i++;
    }

    mlog(ML_NOTICE, "%d reservations found. LRU follows\n", i);

    i = 0;
    list_for_each_entry(resv, &resmap->m_lru, r_lru) {
        mlog(ML_NOTICE, "LRU(%d) start: %u\tend: %u\tlen: %u\t"
             "last_start: %u\tlast_len: %u\n", i, resv->r_start,
             ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
             resv->r_last_len);

        i++;
    }
}

#ifdef OCFS2_CHECK_RESERVATIONS
static int ocfs2_validate_resmap_bits(struct ocfs2_reservation_map *resmap,
                      int i,
                      struct ocfs2_alloc_reservation *resv)
{
    char *disk_bitmap = resmap->m_disk_bitmap;
    unsigned int start = resv->r_start;
    unsigned int end = ocfs2_resv_end(resv);

    while (start <= end) {
        if (ocfs2_test_bit(start, disk_bitmap)) {
            mlog(ML_ERROR,
                 "reservation %d covers an allocated area "
                 "starting at bit %u!\n", i, start);
            return 1;
        }

        start++;
    }
    return 0;
}

static void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
{
    unsigned int off = 0;
    int i = 0;
    struct rb_node *node;
    struct ocfs2_alloc_reservation *resv;

    node = rb_first(&resmap->m_reservations);
    while (node) {
        resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);

        if (i > 0 && resv->r_start <= off) {
            mlog(ML_ERROR, "reservation %d has bad start off!\n",
                 i);
            goto bad;
        }

        if (resv->r_len == 0) {
            mlog(ML_ERROR, "reservation %d has no length!\n",
                 i);
            goto bad;
        }

        if (resv->r_start > ocfs2_resv_end(resv)) {
            mlog(ML_ERROR, "reservation %d has invalid range!\n",
                 i);
            goto bad;
        }

        if (ocfs2_resv_end(resv) >= resmap->m_bitmap_len) {
            mlog(ML_ERROR, "reservation %d extends past bitmap!\n",
                 i);
            goto bad;
        }

        if (ocfs2_validate_resmap_bits(resmap, i, resv))
            goto bad;

        off = ocfs2_resv_end(resv);
        node = rb_next(node);

        i++;
    }
    return;

bad:
    ocfs2_dump_resv(resmap);
    BUG();
}
#else
static inline void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
{

}
#endif

void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv)
{
    memset(resv, 0, sizeof(*resv));
    INIT_LIST_HEAD(&resv->r_lru);
}

void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
             unsigned int flags)
{
    BUG_ON(flags & ~OCFS2_RESV_TYPES);

    resv->r_flags |= flags;
}

int ocfs2_resmap_init(struct ocfs2_super *osb,
              struct ocfs2_reservation_map *resmap)
{
    memset(resmap, 0, sizeof(*resmap));

    resmap->m_osb = osb;
    resmap->m_reservations = RB_ROOT;
    /* m_bitmap_len is initialized to zero by the above memset. */
    INIT_LIST_HEAD(&resmap->m_lru);

    return 0;
}

static void ocfs2_resv_mark_lru(struct ocfs2_reservation_map *resmap,
                struct ocfs2_alloc_reservation *resv)
{
    assert_spin_locked(&resv_lock);

    if (!list_empty(&resv->r_lru))
        list_del_init(&resv->r_lru);

    list_add_tail(&resv->r_lru, &resmap->m_lru);
}

static void __ocfs2_resv_trunc(struct ocfs2_alloc_reservation *resv)
{
    resv->r_len = 0;
    resv->r_start = 0;
}

static void ocfs2_resv_remove(struct ocfs2_reservation_map *resmap,
                  struct ocfs2_alloc_reservation *resv)
{
    if (resv->r_flags & OCFS2_RESV_FLAG_INUSE) {
        list_del_init(&resv->r_lru);
        rb_erase(&resv->r_node, &resmap->m_reservations);
        resv->r_flags &= ~OCFS2_RESV_FLAG_INUSE;
    }
}

static void __ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
                 struct ocfs2_alloc_reservation *resv)
{
    assert_spin_locked(&resv_lock);

    __ocfs2_resv_trunc(resv);
    /*
     * last_len and last_start no longer make sense if
     * we're changing the range of our allocations.
     */
    resv->r_last_len = resv->r_last_start = 0;

    ocfs2_resv_remove(resmap, resv);
}

/* does nothing if 'resv' is null */
void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
            struct ocfs2_alloc_reservation *resv)
{
    if (resv) {
        spin_lock(&resv_lock);
        __ocfs2_resv_discard(resmap, resv);
        spin_unlock(&resv_lock);
    }
}

static void ocfs2_resmap_clear_all_resv(struct ocfs2_reservation_map *resmap)
{
    struct rb_node *node;
    struct ocfs2_alloc_reservation *resv;

    assert_spin_locked(&resv_lock);

    while ((node = rb_last(&resmap->m_reservations)) != NULL) {
        resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);

        __ocfs2_resv_discard(resmap, resv);
    }
}

void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
              unsigned int clen, char *disk_bitmap)
{
    if (ocfs2_resmap_disabled(resmap))
        return;

    spin_lock(&resv_lock);

    ocfs2_resmap_clear_all_resv(resmap);
    resmap->m_bitmap_len = clen;
    resmap->m_disk_bitmap = disk_bitmap;

    spin_unlock(&resv_lock);
}

void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap)
{
    /* Does nothing for now. Keep this around for API symmetry */
}

static void ocfs2_resv_insert(struct ocfs2_reservation_map *resmap,
                  struct ocfs2_alloc_reservation *new)
{
    struct rb_root *root = &resmap->m_reservations;
    struct rb_node *parent = NULL;
    struct rb_node **p = &root->rb_node;
    struct ocfs2_alloc_reservation *tmp;

    assert_spin_locked(&resv_lock);

    trace_ocfs2_resv_insert(new->r_start, new->r_len);

    while (*p) {
        parent = *p;

        tmp = rb_entry(parent, struct ocfs2_alloc_reservation, r_node);

        if (new->r_start < tmp->r_start) {
            p = &(*p)->rb_left;

            /*
             * This is a good place to check for
             * overlapping reservations.
             */
            BUG_ON(ocfs2_resv_end(new) >= tmp->r_start);
        } else if (new->r_start > ocfs2_resv_end(tmp)) {
            p = &(*p)->rb_right;
        } else {
            /* This should never happen! */
            mlog(ML_ERROR, "Duplicate reservation window!\n");
            BUG();
        }
    }

    rb_link_node(&new->r_node, parent, p);
    rb_insert_color(&new->r_node, root);
    new->r_flags |= OCFS2_RESV_FLAG_INUSE;

    ocfs2_resv_mark_lru(resmap, new);

    ocfs2_check_resmap(resmap);
}

static struct ocfs2_alloc_reservation *
ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal)
{
    struct ocfs2_alloc_reservation *resv = NULL;
    struct ocfs2_alloc_reservation *prev_resv = NULL;
    struct rb_node *node = resmap->m_reservations.rb_node;

    assert_spin_locked(&resv_lock);

    if (!node)
        return NULL;

    node = rb_first(&resmap->m_reservations);
    while (node) {
        resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);

        if (resv->r_start <= goal && ocfs2_resv_end(resv) >= goal)
            break;

        /* Check if we overshot the reservation just before goal? */
        if (resv->r_start > goal) {
            resv = prev_resv;
            break;
        }

        prev_resv = resv;
        node = rb_next(node);
    }

    return resv;
}

/*
 * We are given a range within the bitmap, which corresponds to a gap
 * inside the reservations tree (search_start, search_len). The range
 * can be anything from the whole bitmap, to a gap between
 * reservations.
 *
 * The start value of *rstart is insignificant.
 *
 * This function searches the bitmap range starting at search_start
 * with length search_len for a set of contiguous free bits. We try
 * to find up to 'wanted' bits, but can sometimes return less.
 *
 * Returns the length of allocation, 0 if no free bits are found.
 *
 * *cstart and *clen will also be populated with the result.
 */
static int ocfs2_resmap_find_free_bits(struct ocfs2_reservation_map *resmap,
                       unsigned int wanted,
                       unsigned int search_start,
                       unsigned int search_len,
                       unsigned int *rstart,
                       unsigned int *rlen)
{
    void *bitmap = resmap->m_disk_bitmap;
    unsigned int best_start, best_len = 0;
    int offset, start, found;

    trace_ocfs2_resmap_find_free_bits_begin(search_start, search_len,
                        wanted, resmap->m_bitmap_len);

    found = best_start = best_len = 0;

    start = search_start;
    while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap->m_bitmap_len,
                         start)) != -1) {
        /* Search reached end of the region */
        if (offset >= (search_start + search_len))
            break;

        if (offset == start) {
            /* we found a zero */
            found++;
            /* move start to the next bit to test */
            start++;
        } else {
            /* got a zero after some ones */
            found = 1;
            start = offset + 1;
        }
        if (found > best_len) {
            best_len = found;
            best_start = start - found;
        }

        if (found >= wanted)
            break;
    }

    if (best_len == 0)
        return 0;

    if (best_len >= wanted)
        best_len = wanted;

    *rlen = best_len;
    *rstart = best_start;

    trace_ocfs2_resmap_find_free_bits_end(best_start, best_len);

    return *rlen;
}

static void __ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
                     struct ocfs2_alloc_reservation *resv,
                     unsigned int goal, unsigned int wanted)
{
    struct rb_root *root = &resmap->m_reservations;
    unsigned int gap_start, gap_end, gap_len;
    struct ocfs2_alloc_reservation *prev_resv, *next_resv;
    struct rb_node *prev, *next;
    unsigned int cstart, clen;
    unsigned int best_start = 0, best_len = 0;

    /*
     * Nasty cases to consider:
     *
     * - rbtree is empty
     * - our window should be first in all reservations
     * - our window should be last in all reservations
     * - need to make sure we don't go past end of bitmap
     */
    trace_ocfs2_resv_find_window_begin(resv->r_start, ocfs2_resv_end(resv),
                       goal, wanted, RB_EMPTY_ROOT(root));

    assert_spin_locked(&resv_lock);

    if (RB_EMPTY_ROOT(root)) {
        /*
         * Easiest case - empty tree. We can just take
         * whatever window of free bits we want.
         */
        clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
                           resmap->m_bitmap_len - goal,
                           &cstart, &clen);

        /*
         * This should never happen - the local alloc window
         * will always have free bits when we're called.
         */
        BUG_ON(goal == 0 && clen == 0);

        if (clen == 0)
            return;

        resv->r_start = cstart;
        resv->r_len = clen;

        ocfs2_resv_insert(resmap, resv);
        return;
    }

    prev_resv = ocfs2_find_resv_lhs(resmap, goal);

    if (prev_resv == NULL) {
        /*
         * A NULL here means that the search code couldn't
         * find a window that starts before goal.
         *
         * However, we can take the first window after goal,
         * which is also by definition, the leftmost window in
         * the entire tree. If we can find free bits in the
         * gap between goal and the LHS window, then the
         * reservation can safely be placed there.
         *
         * Otherwise we fall back to a linear search, checking
         * the gaps in between windows for a place to
         * allocate.
         */

        next = rb_first(root);
        next_resv = rb_entry(next, struct ocfs2_alloc_reservation,
                     r_node);

        /*
         * The search should never return such a window. (see
         * comment above
         */
        if (next_resv->r_start <= goal) {
            mlog(ML_ERROR, "goal: %u next_resv: start %u len %u\n",
                 goal, next_resv->r_start, next_resv->r_len);
            ocfs2_dump_resv(resmap);
            BUG();
        }

        clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
                           next_resv->r_start - goal,
                           &cstart, &clen);
        if (clen) {
            best_len = clen;
            best_start = cstart;
            if (best_len == wanted)
                goto out_insert;
        }

        prev_resv = next_resv;
        next_resv = NULL;
    }

    trace_ocfs2_resv_find_window_prev(prev_resv->r_start,
                      ocfs2_resv_end(prev_resv));

    prev = &prev_resv->r_node;

    /* Now we do a linear search for a window, starting at 'prev_rsv' */
    while (1) {
        next = rb_next(prev);
        if (next) {
            next_resv = rb_entry(next,
                         struct ocfs2_alloc_reservation,
                         r_node);

            gap_start = ocfs2_resv_end(prev_resv) + 1;
            gap_end = next_resv->r_start - 1;
            gap_len = gap_end - gap_start + 1;
        } else {
            /*
             * We're at the rightmost edge of the
             * tree. See if a reservation between this
             * window and the end of the bitmap will work.
             */
            gap_start = ocfs2_resv_end(prev_resv) + 1;
            gap_len = resmap->m_bitmap_len - gap_start;
            gap_end = resmap->m_bitmap_len - 1;
        }

        trace_ocfs2_resv_find_window_next(next ? next_resv->r_start: -1,
                    next ? ocfs2_resv_end(next_resv) : -1);
        /*
         * No need to check this gap if we have already found
         * a larger region of free bits.
         */
        if (gap_len <= best_len)
            goto next_resv;

        clen = ocfs2_resmap_find_free_bits(resmap, wanted, gap_start,
                           gap_len, &cstart, &clen);
        if (clen == wanted) {
            best_len = clen;
            best_start = cstart;
            goto out_insert;
        } else if (clen > best_len) {
            best_len = clen;
            best_start = cstart;
        }

next_resv:
        if (!next)
            break;

        prev = next;
        prev_resv = rb_entry(prev, struct ocfs2_alloc_reservation,
                     r_node);
    }

out_insert:
    if (best_len) {
        resv->r_start = best_start;
        resv->r_len = best_len;
        ocfs2_resv_insert(resmap, resv);
    }
}

static void ocfs2_cannibalize_resv(struct ocfs2_reservation_map *resmap,
                   struct ocfs2_alloc_reservation *resv,
                   unsigned int wanted)
{
    struct ocfs2_alloc_reservation *lru_resv;
    int tmpwindow = !!(resv->r_flags & OCFS2_RESV_FLAG_TMP);
    unsigned int min_bits;

    if (!tmpwindow)
        min_bits = ocfs2_resv_window_bits(resmap, resv) >> 1;
    else
        min_bits = wanted; /* We at know the temp window will use all
                    * of these bits */

    /*
     * Take the first reservation off the LRU as our 'target'. We
     * don't try to be smart about it. There might be a case for
     * searching based on size but I don't have enough data to be
     * sure. --Mark (3/16/2010)
     */
    lru_resv = list_first_entry(&resmap->m_lru,
                    struct ocfs2_alloc_reservation, r_lru);

    trace_ocfs2_cannibalize_resv_begin(lru_resv->r_start,
                       lru_resv->r_len,
                       ocfs2_resv_end(lru_resv));

    /*
     * Cannibalize (some or all) of the target reservation and
     * feed it to the current window.
     */
    if (lru_resv->r_len <= min_bits) {
        /*
         * Discard completely if size is less than or equal to a
         * reasonable threshold - 50% of window bits for non temporary
         * windows.
         */
        resv->r_start = lru_resv->r_start;
        resv->r_len = lru_resv->r_len;

        __ocfs2_resv_discard(resmap, lru_resv);
    } else {
        unsigned int shrink;
        if (tmpwindow)
            shrink = min_bits;
        else
            shrink = lru_resv->r_len / 2;

        lru_resv->r_len -= shrink;

        resv->r_start = ocfs2_resv_end(lru_resv) + 1;
        resv->r_len = shrink;
    }

    trace_ocfs2_cannibalize_resv_end(resv->r_start, ocfs2_resv_end(resv),
                     resv->r_len, resv->r_last_start,
                     resv->r_last_len);

    ocfs2_resv_insert(resmap, resv);
}

static void ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
                   struct ocfs2_alloc_reservation *resv,
                   unsigned int wanted)
{
    unsigned int goal = 0;

    BUG_ON(!ocfs2_resv_empty(resv));

    /*
     * Begin by trying to get a window as close to the previous
     * one as possible. Using the most recent allocation as a
     * start goal makes sense.
     */
    if (resv->r_last_len) {
        goal = resv->r_last_start + resv->r_last_len;
        if (goal >= resmap->m_bitmap_len)
            goal = 0;
    }

    __ocfs2_resv_find_window(resmap, resv, goal, wanted);

    /* Search from last alloc didn't work, try once more from beginning. */
    if (ocfs2_resv_empty(resv) && goal != 0)
        __ocfs2_resv_find_window(resmap, resv, 0, wanted);

    if (ocfs2_resv_empty(resv)) {
        /*
         * Still empty? Pull oldest one off the LRU, remove it from
         * tree, put this one in it's place.
         */
        ocfs2_cannibalize_resv(resmap, resv, wanted);
    }

    BUG_ON(ocfs2_resv_empty(resv));
}

int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
               struct ocfs2_alloc_reservation *resv,
               int *cstart, int *clen)
{
    if (resv == NULL || ocfs2_resmap_disabled(resmap))
        return -ENOSPC;

    spin_lock(&resv_lock);

    if (ocfs2_resv_empty(resv)) {
        /*
         * We don't want to over-allocate for temporary
         * windows. Otherwise, we run the risk of fragmenting the
         * allocation space.
         */
        unsigned int wanted = ocfs2_resv_window_bits(resmap, resv);

        if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen)
            wanted = *clen;

        /*
         * Try to get a window here. If it works, we must fall
         * through and test the bitmap . This avoids some
         * ping-ponging of windows due to non-reserved space
         * being allocation before we initialize a window for
         * that inode.
         */
        ocfs2_resv_find_window(resmap, resv, wanted);
        trace_ocfs2_resmap_resv_bits(resv->r_start, resv->r_len);
    }

    BUG_ON(ocfs2_resv_empty(resv));

    *cstart = resv->r_start;
    *clen = resv->r_len;

    spin_unlock(&resv_lock);
    return 0;
}

static void
    ocfs2_adjust_resv_from_alloc(struct ocfs2_reservation_map *resmap,
                     struct ocfs2_alloc_reservation *resv,
                     unsigned int start, unsigned int end)
{
    unsigned int rhs = 0;
    unsigned int old_end = ocfs2_resv_end(resv);

    BUG_ON(start != resv->r_start || old_end < end);

    /*
     * Completely used? We can remove it then.
     */
    if (old_end == end) {
        __ocfs2_resv_discard(resmap, resv);
        return;
    }

    rhs = old_end - end;

    /*
     * This should have been trapped above.
     */
    BUG_ON(rhs == 0);

    resv->r_start = end + 1;
    resv->r_len = old_end - resv->r_start + 1;
}

void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
                   struct ocfs2_alloc_reservation *resv,
                   u32 cstart, u32 clen)
{
    unsigned int cend = cstart + clen - 1;

    if (resmap == NULL || ocfs2_resmap_disabled(resmap))
        return;

    if (resv == NULL)
        return;

    BUG_ON(cstart != resv->r_start);

    spin_lock(&resv_lock);

    trace_ocfs2_resmap_claimed_bits_begin(cstart, cend, clen, resv->r_start,
                          ocfs2_resv_end(resv), resv->r_len,
                          resv->r_last_start,
                          resv->r_last_len);

    BUG_ON(cstart < resv->r_start);
    BUG_ON(cstart > ocfs2_resv_end(resv));
    BUG_ON(cend > ocfs2_resv_end(resv));

    ocfs2_adjust_resv_from_alloc(resmap, resv, cstart, cend);
    resv->r_last_start = cstart;
    resv->r_last_len = clen;

    /*
     * May have been discarded above from
     * ocfs2_adjust_resv_from_alloc().
     */
    if (!ocfs2_resv_empty(resv))
        ocfs2_resv_mark_lru(resmap, resv);

    trace_ocfs2_resmap_claimed_bits_end(resv->r_start, ocfs2_resv_end(resv),
                        resv->r_len, resv->r_last_start,
                        resv->r_last_len);

    ocfs2_check_resmap(resmap);

    spin_unlock(&resv_lock);
}