restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace pid

[linux-2.6] / fs / gfs2 / rgrp.c

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>

#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "lops.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "super.h"
#include "trans.h"
#include "ops_file.h"
#include "util.h"
#include "log.h"
#include "inode.h"

#define BFITNOENT ((u32)~0)
#define NO_BLOCK ((u64)~0)

/*
 * These routines are used by the resource group routines (rgrp.c)
 * to keep track of block allocation.  Each block is represented by two
 * bits.  So, each byte represents GFS2_NBBY (i.e. 4) blocks.
 *
 * 0 = Free
 * 1 = Used (not metadata)
 * 2 = Unlinked (still in use) inode
 * 3 = Used (metadata)
 */

static const char valid_change[16] = {
                /* current */
        /* n */ 0, 1, 1, 1,
        /* e */ 1, 0, 0, 0,
        /* w */ 0, 0, 0, 1,
                1, 0, 0, 0
};

static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
                        unsigned char old_state, unsigned char new_state);

/**
 * gfs2_setbit - Set a bit in the bitmaps
 * @buffer: the buffer that holds the bitmaps
 * @buflen: the length (in bytes) of the buffer
 * @block: the block to set
 * @new_state: the new state of the block
 *
 */

static void gfs2_setbit(struct gfs2_rgrpd *rgd, unsigned char *buffer,
                        unsigned int buflen, u32 block,
                        unsigned char new_state)
{
        unsigned char *byte, *end, cur_state;
        unsigned int bit;

        byte = buffer + (block / GFS2_NBBY);
        bit = (block % GFS2_NBBY) * GFS2_BIT_SIZE;
        end = buffer + buflen;

        gfs2_assert(rgd->rd_sbd, byte < end);

        cur_state = (*byte >> bit) & GFS2_BIT_MASK;

        if (valid_change[new_state * 4 + cur_state]) {
                *byte ^= cur_state << bit;
                *byte |= new_state << bit;
        } else
                gfs2_consist_rgrpd(rgd);
}

/**
 * gfs2_testbit - test a bit in the bitmaps
 * @buffer: the buffer that holds the bitmaps
 * @buflen: the length (in bytes) of the buffer
 * @block: the block to read
 *
 */

static unsigned char gfs2_testbit(struct gfs2_rgrpd *rgd, unsigned char *buffer,
                                  unsigned int buflen, u32 block)
{
        unsigned char *byte, *end, cur_state;
        unsigned int bit;

        byte = buffer + (block / GFS2_NBBY);
        bit = (block % GFS2_NBBY) * GFS2_BIT_SIZE;
        end = buffer + buflen;

        gfs2_assert(rgd->rd_sbd, byte < end);

        cur_state = (*byte >> bit) & GFS2_BIT_MASK;

        return cur_state;
}

/**
 * gfs2_bitfit - Search an rgrp's bitmap buffer to find a bit-pair representing
 *       a block in a given allocation state.
 * @buffer: the buffer that holds the bitmaps
 * @buflen: the length (in bytes) of the buffer
 * @goal: start search at this block's bit-pair (within @buffer)
 * @old_state: GFS2_BLKST_XXX the state of the block we're looking for.
 *
 * Scope of @goal and returned block number is only within this bitmap buffer,
 * not entire rgrp or filesystem.  @buffer will be offset from the actual
 * beginning of a bitmap block buffer, skipping any header structures.
 *
 * Return: the block number (bitmap buffer scope) that was found
 */

static u32 gfs2_bitfit(struct gfs2_rgrpd *rgd, unsigned char *buffer,
                            unsigned int buflen, u32 goal,
                            unsigned char old_state)
{
        unsigned char *byte, *end, alloc;
        u32 blk = goal;
        unsigned int bit;

        byte = buffer + (goal / GFS2_NBBY);
        bit = (goal % GFS2_NBBY) * GFS2_BIT_SIZE;
        end = buffer + buflen;
        alloc = (old_state == GFS2_BLKST_FREE) ? 0x55 : 0;

        while (byte < end) {
                /* If we're looking for a free block we can eliminate all
                   bitmap settings with 0x55, which represents four data
                   blocks in a row.  If we're looking for a data block, we can
                   eliminate 0x00 which corresponds to four free blocks. */
                if ((*byte & 0x55) == alloc) {
                        blk += (8 - bit) >> 1;

                        bit = 0;
                        byte++;

                        continue;
                }

                if (((*byte >> bit) & GFS2_BIT_MASK) == old_state)
                        return blk;

                bit += GFS2_BIT_SIZE;
                if (bit >= 8) {
                        bit = 0;
                        byte++;
                }

                blk++;
        }

        return BFITNOENT;
}

/**
 * gfs2_bitcount - count the number of bits in a certain state
 * @buffer: the buffer that holds the bitmaps
 * @buflen: the length (in bytes) of the buffer
 * @state: the state of the block we're looking for
 *
 * Returns: The number of bits
 */

static u32 gfs2_bitcount(struct gfs2_rgrpd *rgd, unsigned char *buffer,
                              unsigned int buflen, unsigned char state)
{
        unsigned char *byte = buffer;
        unsigned char *end = buffer + buflen;
        unsigned char state1 = state << 2;
        unsigned char state2 = state << 4;
        unsigned char state3 = state << 6;
        u32 count = 0;

        for (; byte < end; byte++) {
                if (((*byte) & 0x03) == state)
                        count++;
                if (((*byte) & 0x0C) == state1)
                        count++;
                if (((*byte) & 0x30) == state2)
                        count++;
                if (((*byte) & 0xC0) == state3)
                        count++;
        }

        return count;
}

/**
 * gfs2_rgrp_verify - Verify that a resource group is consistent
 * @sdp: the filesystem
 * @rgd: the rgrp
 *
 */

void gfs2_rgrp_verify(struct gfs2_rgrpd *rgd)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        struct gfs2_bitmap *bi = NULL;
        u32 length = rgd->rd_length;
        u32 count[4], tmp;
        int buf, x;

        memset(count, 0, 4 * sizeof(u32));

        /* Count # blocks in each of 4 possible allocation states */
        for (buf = 0; buf < length; buf++) {
                bi = rgd->rd_bits + buf;
                for (x = 0; x < 4; x++)
                        count[x] += gfs2_bitcount(rgd,
                                                  bi->bi_bh->b_data +
                                                  bi->bi_offset,
                                                  bi->bi_len, x);
        }

        if (count[0] != rgd->rd_rg.rg_free) {
                if (gfs2_consist_rgrpd(rgd))
                        fs_err(sdp, "free data mismatch:  %u != %u\n",
                               count[0], rgd->rd_rg.rg_free);
                return;
        }

        tmp = rgd->rd_data -
                rgd->rd_rg.rg_free -
                rgd->rd_rg.rg_dinodes;
        if (count[1] + count[2] != tmp) {
                if (gfs2_consist_rgrpd(rgd))
                        fs_err(sdp, "used data mismatch:  %u != %u\n",
                               count[1], tmp);
                return;
        }

        if (count[3] != rgd->rd_rg.rg_dinodes) {
                if (gfs2_consist_rgrpd(rgd))
                        fs_err(sdp, "used metadata mismatch:  %u != %u\n",
                               count[3], rgd->rd_rg.rg_dinodes);
                return;
        }

        if (count[2] > count[3]) {
                if (gfs2_consist_rgrpd(rgd))
                        fs_err(sdp, "unlinked inodes > inodes:  %u\n",
                               count[2]);
                return;
        }

}

static inline int rgrp_contains_block(struct gfs2_rgrpd *rgd, u64 block)
{
        u64 first = rgd->rd_data0;
        u64 last = first + rgd->rd_data;
        return first <= block && block < last;
}

/**
 * gfs2_blk2rgrpd - Find resource group for a given data/meta block number
 * @sdp: The GFS2 superblock
 * @n: The data block number
 *
 * Returns: The resource group, or NULL if not found
 */

struct gfs2_rgrpd *gfs2_blk2rgrpd(struct gfs2_sbd *sdp, u64 blk)
{
        struct gfs2_rgrpd *rgd;

        spin_lock(&sdp->sd_rindex_spin);

        list_for_each_entry(rgd, &sdp->sd_rindex_mru_list, rd_list_mru) {
                if (rgrp_contains_block(rgd, blk)) {
                        list_move(&rgd->rd_list_mru, &sdp->sd_rindex_mru_list);
                        spin_unlock(&sdp->sd_rindex_spin);
                        return rgd;
                }
        }

        spin_unlock(&sdp->sd_rindex_spin);

        return NULL;
}

/**
 * gfs2_rgrpd_get_first - get the first Resource Group in the filesystem
 * @sdp: The GFS2 superblock
 *
 * Returns: The first rgrp in the filesystem
 */

struct gfs2_rgrpd *gfs2_rgrpd_get_first(struct gfs2_sbd *sdp)
{
        gfs2_assert(sdp, !list_empty(&sdp->sd_rindex_list));
        return list_entry(sdp->sd_rindex_list.next, struct gfs2_rgrpd, rd_list);
}

/**
 * gfs2_rgrpd_get_next - get the next RG
 * @rgd: A RG
 *
 * Returns: The next rgrp
 */

struct gfs2_rgrpd *gfs2_rgrpd_get_next(struct gfs2_rgrpd *rgd)
{
        if (rgd->rd_list.next == &rgd->rd_sbd->sd_rindex_list)
                return NULL;
        return list_entry(rgd->rd_list.next, struct gfs2_rgrpd, rd_list);
}

static void clear_rgrpdi(struct gfs2_sbd *sdp)
{
        struct list_head *head;
        struct gfs2_rgrpd *rgd;
        struct gfs2_glock *gl;

        spin_lock(&sdp->sd_rindex_spin);
        sdp->sd_rindex_forward = NULL;
        head = &sdp->sd_rindex_recent_list;
        while (!list_empty(head)) {
                rgd = list_entry(head->next, struct gfs2_rgrpd, rd_recent);
                list_del(&rgd->rd_recent);
        }
        spin_unlock(&sdp->sd_rindex_spin);

        head = &sdp->sd_rindex_list;
        while (!list_empty(head)) {
                rgd = list_entry(head->next, struct gfs2_rgrpd, rd_list);
                gl = rgd->rd_gl;

                list_del(&rgd->rd_list);
                list_del(&rgd->rd_list_mru);

                if (gl) {
                        gl->gl_object = NULL;
                        gfs2_glock_put(gl);
                }

                kfree(rgd->rd_bits);
                kfree(rgd);
        }
}

void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
{
        mutex_lock(&sdp->sd_rindex_mutex);
        clear_rgrpdi(sdp);
        mutex_unlock(&sdp->sd_rindex_mutex);
}

static void gfs2_rindex_print(const struct gfs2_rgrpd *rgd)
{
        printk(KERN_INFO "  ri_addr = %llu\n", (unsigned long long)rgd->rd_addr);
        printk(KERN_INFO "  ri_length = %u\n", rgd->rd_length);
        printk(KERN_INFO "  ri_data0 = %llu\n", (unsigned long long)rgd->rd_data0);
        printk(KERN_INFO "  ri_data = %u\n", rgd->rd_data);
        printk(KERN_INFO "  ri_bitbytes = %u\n", rgd->rd_bitbytes);
}

/**
 * gfs2_compute_bitstructs - Compute the bitmap sizes
 * @rgd: The resource group descriptor
 *
 * Calculates bitmap descriptors, one for each block that contains bitmap data
 *
 * Returns: errno
 */

static int compute_bitstructs(struct gfs2_rgrpd *rgd)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        struct gfs2_bitmap *bi;
        u32 length = rgd->rd_length; /* # blocks in hdr & bitmap */
        u32 bytes_left, bytes;
        int x;

        if (!length)
                return -EINVAL;

        rgd->rd_bits = kcalloc(length, sizeof(struct gfs2_bitmap), GFP_NOFS);
        if (!rgd->rd_bits)
                return -ENOMEM;

        bytes_left = rgd->rd_bitbytes;

        for (x = 0; x < length; x++) {
                bi = rgd->rd_bits + x;

                /* small rgrp; bitmap stored completely in header block */
                if (length == 1) {
                        bytes = bytes_left;
                        bi->bi_offset = sizeof(struct gfs2_rgrp);
                        bi->bi_start = 0;
                        bi->bi_len = bytes;
                /* header block */
                } else if (x == 0) {
                        bytes = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_rgrp);
                        bi->bi_offset = sizeof(struct gfs2_rgrp);
                        bi->bi_start = 0;
                        bi->bi_len = bytes;
                /* last block */
                } else if (x + 1 == length) {
                        bytes = bytes_left;
                        bi->bi_offset = sizeof(struct gfs2_meta_header);
                        bi->bi_start = rgd->rd_bitbytes - bytes_left;
                        bi->bi_len = bytes;
                /* other blocks */
                } else {
                        bytes = sdp->sd_sb.sb_bsize -
                                sizeof(struct gfs2_meta_header);
                        bi->bi_offset = sizeof(struct gfs2_meta_header);
                        bi->bi_start = rgd->rd_bitbytes - bytes_left;
                        bi->bi_len = bytes;
                }

                bytes_left -= bytes;
        }

        if (bytes_left) {
                gfs2_consist_rgrpd(rgd);
                return -EIO;
        }
        bi = rgd->rd_bits + (length - 1);
        if ((bi->bi_start + bi->bi_len) * GFS2_NBBY != rgd->rd_data) {
                if (gfs2_consist_rgrpd(rgd)) {
                        gfs2_rindex_print(rgd);
                        fs_err(sdp, "start=%u len=%u offset=%u\n",
                               bi->bi_start, bi->bi_len, bi->bi_offset);
                }
                return -EIO;
        }

        return 0;
}

/**
 * gfs2_ri_total - Total up the file system space, according to the rindex.
 *
 */
u64 gfs2_ri_total(struct gfs2_sbd *sdp)
{
        u64 total_data = 0;     
        struct inode *inode = sdp->sd_rindex;
        struct gfs2_inode *ip = GFS2_I(inode);
        char buf[sizeof(struct gfs2_rindex)];
        struct file_ra_state ra_state;
        int error, rgrps;

        mutex_lock(&sdp->sd_rindex_mutex);
        file_ra_state_init(&ra_state, inode->i_mapping);
        for (rgrps = 0;; rgrps++) {
                loff_t pos = rgrps * sizeof(struct gfs2_rindex);

                if (pos + sizeof(struct gfs2_rindex) >= ip->i_di.di_size)
                        break;
                error = gfs2_internal_read(ip, &ra_state, buf, &pos,
                                           sizeof(struct gfs2_rindex));
                if (error != sizeof(struct gfs2_rindex))
                        break;
                total_data += be32_to_cpu(((struct gfs2_rindex *)buf)->ri_data);
        }
        mutex_unlock(&sdp->sd_rindex_mutex);
        return total_data;
}

static void gfs2_rindex_in(struct gfs2_rgrpd *rgd, const void *buf)
{
        const struct gfs2_rindex *str = buf;

        rgd->rd_addr = be64_to_cpu(str->ri_addr);
        rgd->rd_length = be32_to_cpu(str->ri_length);
        rgd->rd_data0 = be64_to_cpu(str->ri_data0);
        rgd->rd_data = be32_to_cpu(str->ri_data);
        rgd->rd_bitbytes = be32_to_cpu(str->ri_bitbytes);
}

/**
 * read_rindex_entry - Pull in a new resource index entry from the disk
 * @gl: The glock covering the rindex inode
 *
 * Returns: 0 on success, error code otherwise
 */

static int read_rindex_entry(struct gfs2_inode *ip,
                             struct file_ra_state *ra_state)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        loff_t pos = sdp->sd_rgrps * sizeof(struct gfs2_rindex);
        char buf[sizeof(struct gfs2_rindex)];
        int error;
        struct gfs2_rgrpd *rgd;

        error = gfs2_internal_read(ip, ra_state, buf, &pos,
                                   sizeof(struct gfs2_rindex));
        if (!error)
                return 0;
        if (error != sizeof(struct gfs2_rindex)) {
                if (error > 0)
                        error = -EIO;
                return error;
        }

        rgd = kzalloc(sizeof(struct gfs2_rgrpd), GFP_NOFS);
        error = -ENOMEM;
        if (!rgd)
                return error;

        mutex_init(&rgd->rd_mutex);
        lops_init_le(&rgd->rd_le, &gfs2_rg_lops);
        rgd->rd_sbd = sdp;

        list_add_tail(&rgd->rd_list, &sdp->sd_rindex_list);
        list_add_tail(&rgd->rd_list_mru, &sdp->sd_rindex_mru_list);

        gfs2_rindex_in(rgd, buf);
        error = compute_bitstructs(rgd);
        if (error)
                return error;

        error = gfs2_glock_get(sdp, rgd->rd_addr,
                               &gfs2_rgrp_glops, CREATE, &rgd->rd_gl);
        if (error)
                return error;

        rgd->rd_gl->gl_object = rgd;
        rgd->rd_rg_vn = rgd->rd_gl->gl_vn - 1;
        rgd->rd_flags |= GFS2_RDF_CHECK;
        return error;
}

/**
 * gfs2_ri_update - Pull in a new resource index from the disk
 * @ip: pointer to the rindex inode
 *
 * Returns: 0 on successful update, error code otherwise
 */

static int gfs2_ri_update(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct inode *inode = &ip->i_inode;
        struct file_ra_state ra_state;
        u64 rgrp_count = ip->i_di.di_size;
        int error;

        if (do_div(rgrp_count, sizeof(struct gfs2_rindex))) {
                gfs2_consist_inode(ip);
                return -EIO;
        }

        clear_rgrpdi(sdp);

        file_ra_state_init(&ra_state, inode->i_mapping);
        for (sdp->sd_rgrps = 0; sdp->sd_rgrps < rgrp_count; sdp->sd_rgrps++) {
                error = read_rindex_entry(ip, &ra_state);
                if (error) {
                        clear_rgrpdi(sdp);
                        return error;
                }
        }

        sdp->sd_rindex_vn = ip->i_gl->gl_vn;
        return 0;
}

/**
 * gfs2_ri_update_special - Pull in a new resource index from the disk
 *
 * This is a special version that's safe to call from gfs2_inplace_reserve_i.
 * In this case we know that we don't have any resource groups in memory yet.
 *
 * @ip: pointer to the rindex inode
 *
 * Returns: 0 on successful update, error code otherwise
 */
static int gfs2_ri_update_special(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct inode *inode = &ip->i_inode;
        struct file_ra_state ra_state;
        int error;

        file_ra_state_init(&ra_state, inode->i_mapping);
        for (sdp->sd_rgrps = 0;; sdp->sd_rgrps++) {
                /* Ignore partials */
                if ((sdp->sd_rgrps + 1) * sizeof(struct gfs2_rindex) >
                    ip->i_di.di_size)
                        break;
                error = read_rindex_entry(ip, &ra_state);
                if (error) {
                        clear_rgrpdi(sdp);
                        return error;
                }
        }

        sdp->sd_rindex_vn = ip->i_gl->gl_vn;
        return 0;
}

/**
 * gfs2_rindex_hold - Grab a lock on the rindex
 * @sdp: The GFS2 superblock
 * @ri_gh: the glock holder
 *
 * We grab a lock on the rindex inode to make sure that it doesn't
 * change whilst we are performing an operation. We keep this lock
 * for quite long periods of time compared to other locks. This
 * doesn't matter, since it is shared and it is very, very rarely
 * accessed in the exclusive mode (i.e. only when expanding the filesystem).
 *
 * This makes sure that we're using the latest copy of the resource index
 * special file, which might have been updated if someone expanded the
 * filesystem (via gfs2_grow utility), which adds new resource groups.
 *
 * Returns: 0 on success, error code otherwise
 */

int gfs2_rindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ri_gh)
{
        struct gfs2_inode *ip = GFS2_I(sdp->sd_rindex);
        struct gfs2_glock *gl = ip->i_gl;
        int error;

        error = gfs2_glock_nq_init(gl, LM_ST_SHARED, 0, ri_gh);
        if (error)
                return error;

        /* Read new copy from disk if we don't have the latest */
        if (sdp->sd_rindex_vn != gl->gl_vn) {
                mutex_lock(&sdp->sd_rindex_mutex);
                if (sdp->sd_rindex_vn != gl->gl_vn) {
                        error = gfs2_ri_update(ip);
                        if (error)
                                gfs2_glock_dq_uninit(ri_gh);
                }
                mutex_unlock(&sdp->sd_rindex_mutex);
        }

        return error;
}

static void gfs2_rgrp_in(struct gfs2_rgrp_host *rg, const void *buf)
{
        const struct gfs2_rgrp *str = buf;

        rg->rg_flags = be32_to_cpu(str->rg_flags);
        rg->rg_free = be32_to_cpu(str->rg_free);
        rg->rg_dinodes = be32_to_cpu(str->rg_dinodes);
        rg->rg_igeneration = be64_to_cpu(str->rg_igeneration);
}

static void gfs2_rgrp_out(const struct gfs2_rgrp_host *rg, void *buf)
{
        struct gfs2_rgrp *str = buf;

        str->rg_flags = cpu_to_be32(rg->rg_flags);
        str->rg_free = cpu_to_be32(rg->rg_free);
        str->rg_dinodes = cpu_to_be32(rg->rg_dinodes);
        str->__pad = cpu_to_be32(0);
        str->rg_igeneration = cpu_to_be64(rg->rg_igeneration);
        memset(&str->rg_reserved, 0, sizeof(str->rg_reserved));
}

/**
 * gfs2_rgrp_bh_get - Read in a RG's header and bitmaps
 * @rgd: the struct gfs2_rgrpd describing the RG to read in
 *
 * Read in all of a Resource Group's header and bitmap blocks.
 * Caller must eventually call gfs2_rgrp_relse() to free the bitmaps.
 *
 * Returns: errno
 */

int gfs2_rgrp_bh_get(struct gfs2_rgrpd *rgd)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        struct gfs2_glock *gl = rgd->rd_gl;
        unsigned int length = rgd->rd_length;
        struct gfs2_bitmap *bi;
        unsigned int x, y;
        int error;

        mutex_lock(&rgd->rd_mutex);

        spin_lock(&sdp->sd_rindex_spin);
        if (rgd->rd_bh_count) {
                rgd->rd_bh_count++;
                spin_unlock(&sdp->sd_rindex_spin);
                mutex_unlock(&rgd->rd_mutex);
                return 0;
        }
        spin_unlock(&sdp->sd_rindex_spin);

        for (x = 0; x < length; x++) {
                bi = rgd->rd_bits + x;
                error = gfs2_meta_read(gl, rgd->rd_addr + x, 0, &bi->bi_bh);
                if (error)
                        goto fail;
        }

        for (y = length; y--;) {
                bi = rgd->rd_bits + y;
                error = gfs2_meta_wait(sdp, bi->bi_bh);
                if (error)
                        goto fail;
                if (gfs2_metatype_check(sdp, bi->bi_bh, y ? GFS2_METATYPE_RB :
                                              GFS2_METATYPE_RG)) {
                        error = -EIO;
                        goto fail;
                }
        }

        if (rgd->rd_rg_vn != gl->gl_vn) {
                gfs2_rgrp_in(&rgd->rd_rg, (rgd->rd_bits[0].bi_bh)->b_data);
                rgd->rd_rg_vn = gl->gl_vn;
        }

        spin_lock(&sdp->sd_rindex_spin);
        rgd->rd_free_clone = rgd->rd_rg.rg_free;
        rgd->rd_bh_count++;
        spin_unlock(&sdp->sd_rindex_spin);

        mutex_unlock(&rgd->rd_mutex);

        return 0;

fail:
        while (x--) {
                bi = rgd->rd_bits + x;
                brelse(bi->bi_bh);
                bi->bi_bh = NULL;
                gfs2_assert_warn(sdp, !bi->bi_clone);
        }
        mutex_unlock(&rgd->rd_mutex);

        return error;
}

void gfs2_rgrp_bh_hold(struct gfs2_rgrpd *rgd)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;

        spin_lock(&sdp->sd_rindex_spin);
        gfs2_assert_warn(rgd->rd_sbd, rgd->rd_bh_count);
        rgd->rd_bh_count++;
        spin_unlock(&sdp->sd_rindex_spin);
}

/**
 * gfs2_rgrp_bh_put - Release RG bitmaps read in with gfs2_rgrp_bh_get()
 * @rgd: the struct gfs2_rgrpd describing the RG to read in
 *
 */

void gfs2_rgrp_bh_put(struct gfs2_rgrpd *rgd)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        int x, length = rgd->rd_length;

        spin_lock(&sdp->sd_rindex_spin);
        gfs2_assert_warn(rgd->rd_sbd, rgd->rd_bh_count);
        if (--rgd->rd_bh_count) {
                spin_unlock(&sdp->sd_rindex_spin);
                return;
        }

        for (x = 0; x < length; x++) {
                struct gfs2_bitmap *bi = rgd->rd_bits + x;
                kfree(bi->bi_clone);
                bi->bi_clone = NULL;
                brelse(bi->bi_bh);
                bi->bi_bh = NULL;
        }

        spin_unlock(&sdp->sd_rindex_spin);
}

void gfs2_rgrp_repolish_clones(struct gfs2_rgrpd *rgd)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        unsigned int length = rgd->rd_length;
        unsigned int x;

        for (x = 0; x < length; x++) {
                struct gfs2_bitmap *bi = rgd->rd_bits + x;
                if (!bi->bi_clone)
                        continue;
                memcpy(bi->bi_clone + bi->bi_offset,
                       bi->bi_bh->b_data + bi->bi_offset, bi->bi_len);
        }

        spin_lock(&sdp->sd_rindex_spin);
        rgd->rd_free_clone = rgd->rd_rg.rg_free;
        spin_unlock(&sdp->sd_rindex_spin);
}

/**
 * gfs2_alloc_get - get the struct gfs2_alloc structure for an inode
 * @ip: the incore GFS2 inode structure
 *
 * Returns: the struct gfs2_alloc
 */

struct gfs2_alloc *gfs2_alloc_get(struct gfs2_inode *ip)
{
        struct gfs2_alloc *al = &ip->i_alloc;

        /* FIXME: Should assert that the correct locks are held here... */
        memset(al, 0, sizeof(*al));
        return al;
}

/**
 * try_rgrp_fit - See if a given reservation will fit in a given RG
 * @rgd: the RG data
 * @al: the struct gfs2_alloc structure describing the reservation
 *
 * If there's room for the requested blocks to be allocated from the RG:
 *   Sets the $al_rgd field in @al.
 *
 * Returns: 1 on success (it fits), 0 on failure (it doesn't fit)
 */

static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_alloc *al)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        int ret = 0;

        if (rgd->rd_rg.rg_flags & GFS2_RGF_NOALLOC)
                return 0;

        spin_lock(&sdp->sd_rindex_spin);
        if (rgd->rd_free_clone >= al->al_requested) {
                al->al_rgd = rgd;
                ret = 1;
        }
        spin_unlock(&sdp->sd_rindex_spin);

        return ret;
}

/**
 * try_rgrp_unlink - Look for any unlinked, allocated, but unused inodes
 * @rgd: The rgrp
 *
 * Returns: The inode, if one has been found
 */

static struct inode *try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked)
{
        struct inode *inode;
        u32 goal = 0, block;
        u64 no_addr;
        struct gfs2_sbd *sdp = rgd->rd_sbd;

        for(;;) {
                if (goal >= rgd->rd_data)
                        break;
                down_write(&sdp->sd_log_flush_lock);
                block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED,
                                     GFS2_BLKST_UNLINKED);
                up_write(&sdp->sd_log_flush_lock);
                if (block == BFITNOENT)
                        break;
                /* rgblk_search can return a block < goal, so we need to
                   keep it marching forward. */
                no_addr = block + rgd->rd_data0;
                goal++;
                if (*last_unlinked != NO_BLOCK && no_addr <= *last_unlinked)
                        continue;
                *last_unlinked = no_addr;
                inode = gfs2_inode_lookup(rgd->rd_sbd->sd_vfs, DT_UNKNOWN,
                                          no_addr, -1, 1);
                if (!IS_ERR(inode))
                        return inode;
        }

        rgd->rd_flags &= ~GFS2_RDF_CHECK;
        return NULL;
}

/**
 * recent_rgrp_first - get first RG from "recent" list
 * @sdp: The GFS2 superblock
 * @rglast: address of the rgrp used last
 *
 * Returns: The first rgrp in the recent list
 */

static struct gfs2_rgrpd *recent_rgrp_first(struct gfs2_sbd *sdp,
                                            u64 rglast)
{
        struct gfs2_rgrpd *rgd = NULL;

        spin_lock(&sdp->sd_rindex_spin);

        if (list_empty(&sdp->sd_rindex_recent_list))
                goto out;

        if (!rglast)
                goto first;

        list_for_each_entry(rgd, &sdp->sd_rindex_recent_list, rd_recent) {
                if (rgd->rd_addr == rglast)
                        goto out;
        }

first:
        rgd = list_entry(sdp->sd_rindex_recent_list.next, struct gfs2_rgrpd,
                         rd_recent);
out:
        spin_unlock(&sdp->sd_rindex_spin);
        return rgd;
}

/**
 * recent_rgrp_next - get next RG from "recent" list
 * @cur_rgd: current rgrp
 * @remove:
 *
 * Returns: The next rgrp in the recent list
 */

static struct gfs2_rgrpd *recent_rgrp_next(struct gfs2_rgrpd *cur_rgd,
                                           int remove)
{
        struct gfs2_sbd *sdp = cur_rgd->rd_sbd;
        struct list_head *head;
        struct gfs2_rgrpd *rgd;

        spin_lock(&sdp->sd_rindex_spin);

        head = &sdp->sd_rindex_recent_list;

        list_for_each_entry(rgd, head, rd_recent) {
                if (rgd == cur_rgd) {
                        if (cur_rgd->rd_recent.next != head)
                                rgd = list_entry(cur_rgd->rd_recent.next,
                                                 struct gfs2_rgrpd, rd_recent);
                        else
                                rgd = NULL;

                        if (remove)
                                list_del(&cur_rgd->rd_recent);

                        goto out;
                }
        }

        rgd = NULL;
        if (!list_empty(head))
                rgd = list_entry(head->next, struct gfs2_rgrpd, rd_recent);

out:
        spin_unlock(&sdp->sd_rindex_spin);
        return rgd;
}

/**
 * recent_rgrp_add - add an RG to tail of "recent" list
 * @new_rgd: The rgrp to add
 *
 */

static void recent_rgrp_add(struct gfs2_rgrpd *new_rgd)
{
        struct gfs2_sbd *sdp = new_rgd->rd_sbd;
        struct gfs2_rgrpd *rgd;
        unsigned int count = 0;
        unsigned int max = sdp->sd_rgrps / gfs2_jindex_size(sdp);

        spin_lock(&sdp->sd_rindex_spin);

        list_for_each_entry(rgd, &sdp->sd_rindex_recent_list, rd_recent) {
                if (rgd == new_rgd)
                        goto out;

                if (++count >= max)
                        goto out;
        }
        list_add_tail(&new_rgd->rd_recent, &sdp->sd_rindex_recent_list);

out:
        spin_unlock(&sdp->sd_rindex_spin);
}

/**
 * forward_rgrp_get - get an rgrp to try next from full list
 * @sdp: The GFS2 superblock
 *
 * Returns: The rgrp to try next
 */

static struct gfs2_rgrpd *forward_rgrp_get(struct gfs2_sbd *sdp)
{
        struct gfs2_rgrpd *rgd;
        unsigned int journals = gfs2_jindex_size(sdp);
        unsigned int rg = 0, x;

        spin_lock(&sdp->sd_rindex_spin);

        rgd = sdp->sd_rindex_forward;
        if (!rgd) {
                if (sdp->sd_rgrps >= journals)
                        rg = sdp->sd_rgrps * sdp->sd_jdesc->jd_jid / journals;

                for (x = 0, rgd = gfs2_rgrpd_get_first(sdp); x < rg;
                     x++, rgd = gfs2_rgrpd_get_next(rgd))
                        /* Do Nothing */;

                sdp->sd_rindex_forward = rgd;
        }

        spin_unlock(&sdp->sd_rindex_spin);

        return rgd;
}

/**
 * forward_rgrp_set - set the forward rgrp pointer
 * @sdp: the filesystem
 * @rgd: The new forward rgrp
 *
 */

static void forward_rgrp_set(struct gfs2_sbd *sdp, struct gfs2_rgrpd *rgd)
{
        spin_lock(&sdp->sd_rindex_spin);
        sdp->sd_rindex_forward = rgd;
        spin_unlock(&sdp->sd_rindex_spin);
}

/**
 * get_local_rgrp - Choose and lock a rgrp for allocation
 * @ip: the inode to reserve space for
 * @rgp: the chosen and locked rgrp
 *
 * Try to acquire rgrp in way which avoids contending with others.
 *
 * Returns: errno
 */

static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
{
        struct inode *inode = NULL;
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrpd *rgd, *begin = NULL;
        struct gfs2_alloc *al = &ip->i_alloc;
        int flags = LM_FLAG_TRY;
        int skipped = 0;
        int loops = 0;
        int error;

        /* Try recently successful rgrps */

        rgd = recent_rgrp_first(sdp, ip->i_last_rg_alloc);

        while (rgd) {
                error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE,
                                           LM_FLAG_TRY, &al->al_rgd_gh);
                switch (error) {
                case 0:
                        if (try_rgrp_fit(rgd, al))
                                goto out;
                        if (rgd->rd_flags & GFS2_RDF_CHECK)
                                inode = try_rgrp_unlink(rgd, last_unlinked);
                        gfs2_glock_dq_uninit(&al->al_rgd_gh);
                        if (inode)
                                return inode;
                        rgd = recent_rgrp_next(rgd, 1);
                        break;

                case GLR_TRYFAILED:
                        rgd = recent_rgrp_next(rgd, 0);
                        break;

                default:
                        return ERR_PTR(error);
                }
        }

        /* Go through full list of rgrps */

        begin = rgd = forward_rgrp_get(sdp);

        for (;;) {
                error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE, flags,
                                          &al->al_rgd_gh);
                switch (error) {
                case 0:
                        if (try_rgrp_fit(rgd, al))
                                goto out;
                        if (rgd->rd_flags & GFS2_RDF_CHECK)
                                inode = try_rgrp_unlink(rgd, last_unlinked);
                        gfs2_glock_dq_uninit(&al->al_rgd_gh);
                        if (inode)
                                return inode;
                        break;

                case GLR_TRYFAILED:
                        skipped++;
                        break;

                default:
                        return ERR_PTR(error);
                }

                rgd = gfs2_rgrpd_get_next(rgd);
                if (!rgd)
                        rgd = gfs2_rgrpd_get_first(sdp);

                if (rgd == begin) {
                        if (++loops >= 3)
                                return ERR_PTR(-ENOSPC);
                        if (!skipped)
                                loops++;
                        flags = 0;
                        if (loops == 2)
                                gfs2_log_flush(sdp, NULL);
                }
        }

out:
        ip->i_last_rg_alloc = rgd->rd_addr;

        if (begin) {
                recent_rgrp_add(rgd);
                rgd = gfs2_rgrpd_get_next(rgd);
                if (!rgd)
                        rgd = gfs2_rgrpd_get_first(sdp);
                forward_rgrp_set(sdp, rgd);
        }

        return NULL;
}

/**
 * gfs2_inplace_reserve_i - Reserve space in the filesystem
 * @ip: the inode to reserve space for
 *
 * Returns: errno
 */

int gfs2_inplace_reserve_i(struct gfs2_inode *ip, char *file, unsigned int line)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = &ip->i_alloc;
        struct inode *inode;
        int error = 0;
        u64 last_unlinked = NO_BLOCK;

        if (gfs2_assert_warn(sdp, al->al_requested))
                return -EINVAL;

try_again:
        /* We need to hold the rindex unless the inode we're using is
           the rindex itself, in which case it's already held. */
        if (ip != GFS2_I(sdp->sd_rindex))
                error = gfs2_rindex_hold(sdp, &al->al_ri_gh);
        else if (!sdp->sd_rgrps) /* We may not have the rindex read in, so: */
                error = gfs2_ri_update_special(ip);

        if (error)
                return error;

        inode = get_local_rgrp(ip, &last_unlinked);
        if (inode) {
                if (ip != GFS2_I(sdp->sd_rindex))
                        gfs2_glock_dq_uninit(&al->al_ri_gh);
                if (IS_ERR(inode))
                        return PTR_ERR(inode);
                iput(inode);
                gfs2_log_flush(sdp, NULL);
                goto try_again;
        }

        al->al_file = file;
        al->al_line = line;

        return 0;
}

/**
 * gfs2_inplace_release - release an inplace reservation
 * @ip: the inode the reservation was taken out on
 *
 * Release a reservation made by gfs2_inplace_reserve().
 */

void gfs2_inplace_release(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = &ip->i_alloc;

        if (gfs2_assert_warn(sdp, al->al_alloced <= al->al_requested) == -1)
                fs_warn(sdp, "al_alloced = %u, al_requested = %u "
                             "al_file = %s, al_line = %u\n",
                             al->al_alloced, al->al_requested, al->al_file,
                             al->al_line);

        al->al_rgd = NULL;
        gfs2_glock_dq_uninit(&al->al_rgd_gh);
        if (ip != GFS2_I(sdp->sd_rindex))
                gfs2_glock_dq_uninit(&al->al_ri_gh);
}

/**
 * gfs2_get_block_type - Check a block in a RG is of given type
 * @rgd: the resource group holding the block
 * @block: the block number
 *
 * Returns: The block type (GFS2_BLKST_*)
 */

unsigned char gfs2_get_block_type(struct gfs2_rgrpd *rgd, u64 block)
{
        struct gfs2_bitmap *bi = NULL;
        u32 length, rgrp_block, buf_block;
        unsigned int buf;
        unsigned char type;

        length = rgd->rd_length;
        rgrp_block = block - rgd->rd_data0;

        for (buf = 0; buf < length; buf++) {
                bi = rgd->rd_bits + buf;
                if (rgrp_block < (bi->bi_start + bi->bi_len) * GFS2_NBBY)
                        break;
        }

        gfs2_assert(rgd->rd_sbd, buf < length);
        buf_block = rgrp_block - bi->bi_start * GFS2_NBBY;

        type = gfs2_testbit(rgd, bi->bi_bh->b_data + bi->bi_offset,
                           bi->bi_len, buf_block);

        return type;
}

/**
 * rgblk_search - find a block in @old_state, change allocation
 *           state to @new_state
 * @rgd: the resource group descriptor
 * @goal: the goal block within the RG (start here to search for avail block)
 * @old_state: GFS2_BLKST_XXX the before-allocation state to find
 * @new_state: GFS2_BLKST_XXX the after-allocation block state
 *
 * Walk rgrp's bitmap to find bits that represent a block in @old_state.
 * Add the found bitmap buffer to the transaction.
 * Set the found bits to @new_state to change block's allocation state.
 *
 * This function never fails, because we wouldn't call it unless we
 * know (from reservation results, etc.) that a block is available.
 *
 * Scope of @goal and returned block is just within rgrp, not the whole
 * filesystem.
 *
 * Returns:  the block number allocated
 */

static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
                        unsigned char old_state, unsigned char new_state)
{
        struct gfs2_bitmap *bi = NULL;
        u32 length = rgd->rd_length;
        u32 blk = 0;
        unsigned int buf, x;

        /* Find bitmap block that contains bits for goal block */
        for (buf = 0; buf < length; buf++) {
                bi = rgd->rd_bits + buf;
                if (goal < (bi->bi_start + bi->bi_len) * GFS2_NBBY)
                        break;
        }

        gfs2_assert(rgd->rd_sbd, buf < length);

        /* Convert scope of "goal" from rgrp-wide to within found bit block */
        goal -= bi->bi_start * GFS2_NBBY;

        /* Search (up to entire) bitmap in this rgrp for allocatable block.
           "x <= length", instead of "x < length", because we typically start
           the search in the middle of a bit block, but if we can't find an
           allocatable block anywhere else, we want to be able wrap around and
           search in the first part of our first-searched bit block.  */
        for (x = 0; x <= length; x++) {
                /* The GFS2_BLKST_UNLINKED state doesn't apply to the clone
                   bitmaps, so we must search the originals for that. */
                if (old_state != GFS2_BLKST_UNLINKED && bi->bi_clone)
                        blk = gfs2_bitfit(rgd, bi->bi_clone + bi->bi_offset,
                                          bi->bi_len, goal, old_state);
                else
                        blk = gfs2_bitfit(rgd,
                                          bi->bi_bh->b_data + bi->bi_offset,
                                          bi->bi_len, goal, old_state);
                if (blk != BFITNOENT)
                        break;

                /* Try next bitmap block (wrap back to rgrp header if at end) */
                buf = (buf + 1) % length;
                bi = rgd->rd_bits + buf;
                goal = 0;
        }

        if (blk != BFITNOENT && old_state != new_state) {
                gfs2_trans_add_bh(rgd->rd_gl, bi->bi_bh, 1);
                gfs2_setbit(rgd, bi->bi_bh->b_data + bi->bi_offset,
                            bi->bi_len, blk, new_state);
                if (bi->bi_clone)
                        gfs2_setbit(rgd, bi->bi_clone + bi->bi_offset,
                                    bi->bi_len, blk, new_state);
        }

        return (blk == BFITNOENT) ? blk : (bi->bi_start * GFS2_NBBY) + blk;
}

/**
 * rgblk_free - Change alloc state of given block(s)
 * @sdp: the filesystem
 * @bstart: the start of a run of blocks to free
 * @blen: the length of the block run (all must lie within ONE RG!)
 * @new_state: GFS2_BLKST_XXX the after-allocation block state
 *
 * Returns:  Resource group containing the block(s)
 */

static struct gfs2_rgrpd *rgblk_free(struct gfs2_sbd *sdp, u64 bstart,
                                     u32 blen, unsigned char new_state)
{
        struct gfs2_rgrpd *rgd;
        struct gfs2_bitmap *bi = NULL;
        u32 length, rgrp_blk, buf_blk;
        unsigned int buf;

        rgd = gfs2_blk2rgrpd(sdp, bstart);
        if (!rgd) {
                if (gfs2_consist(sdp))
                        fs_err(sdp, "block = %llu\n", (unsigned long long)bstart);
                return NULL;
        }

        length = rgd->rd_length;

        rgrp_blk = bstart - rgd->rd_data0;

        while (blen--) {
                for (buf = 0; buf < length; buf++) {
                        bi = rgd->rd_bits + buf;
                        if (rgrp_blk < (bi->bi_start + bi->bi_len) * GFS2_NBBY)
                                break;
                }

                gfs2_assert(rgd->rd_sbd, buf < length);

                buf_blk = rgrp_blk - bi->bi_start * GFS2_NBBY;
                rgrp_blk++;

                if (!bi->bi_clone) {
                        bi->bi_clone = kmalloc(bi->bi_bh->b_size,
                                               GFP_NOFS | __GFP_NOFAIL);
                        memcpy(bi->bi_clone + bi->bi_offset,
                               bi->bi_bh->b_data + bi->bi_offset,
                               bi->bi_len);
                }
                gfs2_trans_add_bh(rgd->rd_gl, bi->bi_bh, 1);
                gfs2_setbit(rgd, bi->bi_bh->b_data + bi->bi_offset,
                            bi->bi_len, buf_blk, new_state);
        }

        return rgd;
}

/**
 * gfs2_alloc_data - Allocate a data block
 * @ip: the inode to allocate the data block for
 *
 * Returns: the allocated block
 */

u64 gfs2_alloc_data(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = &ip->i_alloc;
        struct gfs2_rgrpd *rgd = al->al_rgd;
        u32 goal, blk;
        u64 block;

        if (rgrp_contains_block(rgd, ip->i_di.di_goal_data))
                goal = ip->i_di.di_goal_data - rgd->rd_data0;
        else
                goal = rgd->rd_last_alloc_data;

        blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, GFS2_BLKST_USED);
        BUG_ON(blk == BFITNOENT);
        rgd->rd_last_alloc_data = blk;

        block = rgd->rd_data0 + blk;
        ip->i_di.di_goal_data = block;

        gfs2_assert_withdraw(sdp, rgd->rd_rg.rg_free);
        rgd->rd_rg.rg_free--;

        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);

        al->al_alloced++;

        gfs2_statfs_change(sdp, 0, -1, 0);
        gfs2_quota_change(ip, +1, ip->i_inode.i_uid, ip->i_inode.i_gid);

        spin_lock(&sdp->sd_rindex_spin);
        rgd->rd_free_clone--;
        spin_unlock(&sdp->sd_rindex_spin);

        return block;
}

/**
 * gfs2_alloc_meta - Allocate a metadata block
 * @ip: the inode to allocate the metadata block for
 *
 * Returns: the allocated block
 */

u64 gfs2_alloc_meta(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = &ip->i_alloc;
        struct gfs2_rgrpd *rgd = al->al_rgd;
        u32 goal, blk;
        u64 block;

        if (rgrp_contains_block(rgd, ip->i_di.di_goal_meta))
                goal = ip->i_di.di_goal_meta - rgd->rd_data0;
        else
                goal = rgd->rd_last_alloc_meta;

        blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, GFS2_BLKST_USED);
        BUG_ON(blk == BFITNOENT);
        rgd->rd_last_alloc_meta = blk;

        block = rgd->rd_data0 + blk;
        ip->i_di.di_goal_meta = block;

        gfs2_assert_withdraw(sdp, rgd->rd_rg.rg_free);
        rgd->rd_rg.rg_free--;

        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);

        al->al_alloced++;

        gfs2_statfs_change(sdp, 0, -1, 0);
        gfs2_quota_change(ip, +1, ip->i_inode.i_uid, ip->i_inode.i_gid);
        gfs2_trans_add_unrevoke(sdp, block);

        spin_lock(&sdp->sd_rindex_spin);
        rgd->rd_free_clone--;
        spin_unlock(&sdp->sd_rindex_spin);

        return block;
}

/**
 * gfs2_alloc_di - Allocate a dinode
 * @dip: the directory that the inode is going in
 *
 * Returns: the block allocated
 */

u64 gfs2_alloc_di(struct gfs2_inode *dip, u64 *generation)
{
        struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
        struct gfs2_alloc *al = &dip->i_alloc;
        struct gfs2_rgrpd *rgd = al->al_rgd;
        u32 blk;
        u64 block;

        blk = rgblk_search(rgd, rgd->rd_last_alloc_meta,
                           GFS2_BLKST_FREE, GFS2_BLKST_DINODE);
        BUG_ON(blk == BFITNOENT);

        rgd->rd_last_alloc_meta = blk;

        block = rgd->rd_data0 + blk;

        gfs2_assert_withdraw(sdp, rgd->rd_rg.rg_free);
        rgd->rd_rg.rg_free--;
        rgd->rd_rg.rg_dinodes++;
        *generation = rgd->rd_rg.rg_igeneration++;
        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);

        al->al_alloced++;

        gfs2_statfs_change(sdp, 0, -1, +1);
        gfs2_trans_add_unrevoke(sdp, block);

        spin_lock(&sdp->sd_rindex_spin);
        rgd->rd_free_clone--;
        spin_unlock(&sdp->sd_rindex_spin);

        return block;
}

/**
 * gfs2_free_data - free a contiguous run of data block(s)
 * @ip: the inode these blocks are being freed from
 * @bstart: first block of a run of contiguous blocks
 * @blen: the length of the block run
 *
 */

void gfs2_free_data(struct gfs2_inode *ip, u64 bstart, u32 blen)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrpd *rgd;

        rgd = rgblk_free(sdp, bstart, blen, GFS2_BLKST_FREE);
        if (!rgd)
                return;

        rgd->rd_rg.rg_free += blen;

        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);

        gfs2_trans_add_rg(rgd);

        gfs2_statfs_change(sdp, 0, +blen, 0);
        gfs2_quota_change(ip, -(s64)blen, ip->i_inode.i_uid, ip->i_inode.i_gid);
}

/**
 * gfs2_free_meta - free a contiguous run of data block(s)
 * @ip: the inode these blocks are being freed from
 * @bstart: first block of a run of contiguous blocks
 * @blen: the length of the block run
 *
 */

void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrpd *rgd;

        rgd = rgblk_free(sdp, bstart, blen, GFS2_BLKST_FREE);
        if (!rgd)
                return;

        rgd->rd_rg.rg_free += blen;

        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);

        gfs2_trans_add_rg(rgd);

        gfs2_statfs_change(sdp, 0, +blen, 0);
        gfs2_quota_change(ip, -(s64)blen, ip->i_inode.i_uid, ip->i_inode.i_gid);
        gfs2_meta_wipe(ip, bstart, blen);
}

void gfs2_unlink_di(struct inode *inode)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_sbd *sdp = GFS2_SB(inode);
        struct gfs2_rgrpd *rgd;
        u64 blkno = ip->i_no_addr;

        rgd = rgblk_free(sdp, blkno, 1, GFS2_BLKST_UNLINKED);
        if (!rgd)
                return;
        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);
        gfs2_trans_add_rg(rgd);
}

static void gfs2_free_uninit_di(struct gfs2_rgrpd *rgd, u64 blkno)
{
        struct gfs2_sbd *sdp = rgd->rd_sbd;
        struct gfs2_rgrpd *tmp_rgd;

        tmp_rgd = rgblk_free(sdp, blkno, 1, GFS2_BLKST_FREE);
        if (!tmp_rgd)
                return;
        gfs2_assert_withdraw(sdp, rgd == tmp_rgd);

        if (!rgd->rd_rg.rg_dinodes)
                gfs2_consist_rgrpd(rgd);
        rgd->rd_rg.rg_dinodes--;
        rgd->rd_rg.rg_free++;

        gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
        gfs2_rgrp_out(&rgd->rd_rg, rgd->rd_bits[0].bi_bh->b_data);

        gfs2_statfs_change(sdp, 0, +1, -1);
        gfs2_trans_add_rg(rgd);
}


void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip)
{
        gfs2_free_uninit_di(rgd, ip->i_no_addr);
        gfs2_quota_change(ip, -1, ip->i_inode.i_uid, ip->i_inode.i_gid);
        gfs2_meta_wipe(ip, ip->i_no_addr, 1);
}

/**
 * gfs2_rlist_add - add a RG to a list of RGs
 * @sdp: the filesystem
 * @rlist: the list of resource groups
 * @block: the block
 *
 * Figure out what RG a block belongs to and add that RG to the list
 *
 * FIXME: Don't use NOFAIL
 *
 */

void gfs2_rlist_add(struct gfs2_sbd *sdp, struct gfs2_rgrp_list *rlist,
                    u64 block)
{
        struct gfs2_rgrpd *rgd;
        struct gfs2_rgrpd **tmp;
        unsigned int new_space;
        unsigned int x;

        if (gfs2_assert_warn(sdp, !rlist->rl_ghs))
                return;

        rgd = gfs2_blk2rgrpd(sdp, block);
        if (!rgd) {
                if (gfs2_consist(sdp))
                        fs_err(sdp, "block = %llu\n", (unsigned long long)block);
                return;
        }

        for (x = 0; x < rlist->rl_rgrps; x++)
                if (rlist->rl_rgd[x] == rgd)
                        return;

        if (rlist->rl_rgrps == rlist->rl_space) {
                new_space = rlist->rl_space + 10;

                tmp = kcalloc(new_space, sizeof(struct gfs2_rgrpd *),
                              GFP_NOFS | __GFP_NOFAIL);

                if (rlist->rl_rgd) {
                        memcpy(tmp, rlist->rl_rgd,
                               rlist->rl_space * sizeof(struct gfs2_rgrpd *));
                        kfree(rlist->rl_rgd);
                }

                rlist->rl_space = new_space;
                rlist->rl_rgd = tmp;
        }

        rlist->rl_rgd[rlist->rl_rgrps++] = rgd;
}

/**
 * gfs2_rlist_alloc - all RGs have been added to the rlist, now allocate
 *      and initialize an array of glock holders for them
 * @rlist: the list of resource groups
 * @state: the lock state to acquire the RG lock in
 * @flags: the modifier flags for the holder structures
 *
 * FIXME: Don't use NOFAIL
 *
 */

void gfs2_rlist_alloc(struct gfs2_rgrp_list *rlist, unsigned int state,
                      int flags)
{
        unsigned int x;

        rlist->rl_ghs = kcalloc(rlist->rl_rgrps, sizeof(struct gfs2_holder),
                                GFP_NOFS | __GFP_NOFAIL);
        for (x = 0; x < rlist->rl_rgrps; x++)
                gfs2_holder_init(rlist->rl_rgd[x]->rd_gl,
                                state, flags,
                                &rlist->rl_ghs[x]);
}

/**
 * gfs2_rlist_free - free a resource group list
 * @list: the list of resource groups
 *
 */

void gfs2_rlist_free(struct gfs2_rgrp_list *rlist)
{
        unsigned int x;

        kfree(rlist->rl_rgd);

        if (rlist->rl_ghs) {
                for (x = 0; x < rlist->rl_rgrps; x++)
                        gfs2_holder_uninit(&rlist->rl_ghs[x]);
                kfree(rlist->rl_ghs);
        }
}