rgrp.c

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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2008 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/prefetch.h>
#include <linux/blkdev.h>
#include <linux/rbtree.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 "util.h"
#include "log.h"
#include "inode.h"
#include "trace_gfs2.h"

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

#if BITS_PER_LONG == 32
#define LBITMASK   (0x55555555UL)
#define LBITSKIP55 (0x55555555UL)
#define LBITSKIP00 (0x00000000UL)
#else
#define LBITMASK   (0x5555555555555555UL)
#define LBITSKIP55 (0x5555555555555555UL)
#define LBITSKIP00 (0x0000000000000000UL)
#endif

/*
 * 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 int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 minext,
                         const struct gfs2_inode *ip, bool nowrap);


static inline void gfs2_setbit(const struct gfs2_rbm *rbm, bool do_clone,
                   unsigned char new_state)
{
    unsigned char *byte1, *byte2, *end, cur_state;
    unsigned int buflen = rbm->bi->bi_len;
    const unsigned int bit = (rbm->offset % GFS2_NBBY) * GFS2_BIT_SIZE;

    byte1 = rbm->bi->bi_bh->b_data + rbm->bi->bi_offset + (rbm->offset / GFS2_NBBY);
    end = rbm->bi->bi_bh->b_data + rbm->bi->bi_offset + buflen;

    BUG_ON(byte1 >= end);

    cur_state = (*byte1 >> bit) & GFS2_BIT_MASK;

    if (unlikely(!valid_change[new_state * 4 + cur_state])) {
        printk(KERN_WARNING "GFS2: buf_blk = 0x%x old_state=%d, "
               "new_state=%d\n", rbm->offset, cur_state, new_state);
        printk(KERN_WARNING "GFS2: rgrp=0x%llx bi_start=0x%x\n",
               (unsigned long long)rbm->rgd->rd_addr,
               rbm->bi->bi_start);
        printk(KERN_WARNING "GFS2: bi_offset=0x%x bi_len=0x%x\n",
               rbm->bi->bi_offset, rbm->bi->bi_len);
        dump_stack();
        gfs2_consist_rgrpd(rbm->rgd);
        return;
    }
    *byte1 ^= (cur_state ^ new_state) << bit;

    if (do_clone && rbm->bi->bi_clone) {
        byte2 = rbm->bi->bi_clone + rbm->bi->bi_offset + (rbm->offset / GFS2_NBBY);
        cur_state = (*byte2 >> bit) & GFS2_BIT_MASK;
        *byte2 ^= (cur_state ^ new_state) << bit;
    }
}

static inline u8 gfs2_testbit(const struct gfs2_rbm *rbm)
{
    const u8 *buffer = rbm->bi->bi_bh->b_data + rbm->bi->bi_offset;
    const u8 *byte;
    unsigned int bit;

    byte = buffer + (rbm->offset / GFS2_NBBY);
    bit = (rbm->offset % GFS2_NBBY) * GFS2_BIT_SIZE;

    return (*byte >> bit) & GFS2_BIT_MASK;
}

static inline u64 gfs2_bit_search(const __le64 *ptr, u64 mask, u8 state)
{
    u64 tmp;
    static const u64 search[] = {
        [0] = 0xffffffffffffffffULL,
        [1] = 0xaaaaaaaaaaaaaaaaULL,
        [2] = 0x5555555555555555ULL,
        [3] = 0x0000000000000000ULL,
    };
    tmp = le64_to_cpu(*ptr) ^ search[state];
    tmp &= (tmp >> 1);
    tmp &= mask;
    return tmp;
}

static inline int rs_cmp(u64 blk, u32 len, struct gfs2_blkreserv *rs)
{
    u64 startblk = gfs2_rbm_to_block(&rs->rs_rbm);

    if (blk >= startblk + rs->rs_free)
        return 1;
    if (blk + len - 1 < startblk)
        return -1;
    return 0;
}

static u32 gfs2_bitfit(const u8 *buf, const unsigned int len,
               u32 goal, u8 state)
{
    u32 spoint = (goal << 1) & ((8*sizeof(u64)) - 1);
    const __le64 *ptr = ((__le64 *)buf) + (goal >> 5);
    const __le64 *end = (__le64 *)(buf + ALIGN(len, sizeof(u64)));
    u64 tmp;
    u64 mask = 0x5555555555555555ULL;
    u32 bit;

    /* Mask off bits we don't care about at the start of the search */
    mask <<= spoint;
    tmp = gfs2_bit_search(ptr, mask, state);
    ptr++;
    while(tmp == 0 && ptr < end) {
        tmp = gfs2_bit_search(ptr, 0x5555555555555555ULL, state);
        ptr++;
    }
    /* Mask off any bits which are more than len bytes from the start */
    if (ptr == end && (len & (sizeof(u64) - 1)))
        tmp &= (((u64)~0) >> (64 - 8*(len & (sizeof(u64) - 1))));
    /* Didn't find anything, so return */
    if (tmp == 0)
        return BFITNOENT;
    ptr--;
    bit = __ffs64(tmp);
    bit /= 2;   /* two bits per entry in the bitmap */
    return (((const unsigned char *)ptr - buf) * GFS2_NBBY) + bit;
}

static int gfs2_rbm_from_block(struct gfs2_rbm *rbm, u64 block)
{
    u64 rblock = block - rbm->rgd->rd_data0;
    u32 goal = (u32)rblock;
    int x;

    if (WARN_ON_ONCE(rblock > UINT_MAX))
        return -EINVAL;
    if (block >= rbm->rgd->rd_data0 + rbm->rgd->rd_data)
        return -E2BIG;

    for (x = 0; x < rbm->rgd->rd_length; x++) {
        rbm->bi = rbm->rgd->rd_bits + x;
        if (goal < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) {
            rbm->offset = goal - (rbm->bi->bi_start * GFS2_NBBY);
            break;
        }
    }

    return 0;
}

static bool gfs2_unaligned_extlen(struct gfs2_rbm *rbm, u32 n_unaligned, u32 *len)
{
    u64 block;
    u32 n;
    u8 res;

    for (n = 0; n < n_unaligned; n++) {
        res = gfs2_testbit(rbm);
        if (res != GFS2_BLKST_FREE)
            return true;
        (*len)--;
        if (*len == 0)
            return true;
        block = gfs2_rbm_to_block(rbm);
        if (gfs2_rbm_from_block(rbm, block + 1))
            return true;
    }

    return false;
}

static u32 gfs2_free_extlen(const struct gfs2_rbm *rrbm, u32 len)
{
    struct gfs2_rbm rbm = *rrbm;
    u32 n_unaligned = rbm.offset & 3;
    u32 size = len;
    u32 bytes;
    u32 chunk_size;
    u8 *ptr, *start, *end;
    u64 block;

    if (n_unaligned &&
        gfs2_unaligned_extlen(&rbm, 4 - n_unaligned, &len))
        goto out;

    n_unaligned = len & 3;
    /* Start is now byte aligned */
    while (len > 3) {
        start = rbm.bi->bi_bh->b_data;
        if (rbm.bi->bi_clone)
            start = rbm.bi->bi_clone;
        end = start + rbm.bi->bi_bh->b_size;
        start += rbm.bi->bi_offset;
        BUG_ON(rbm.offset & 3);
        start += (rbm.offset / GFS2_NBBY);
        bytes = min_t(u32, len / GFS2_NBBY, (end - start));
        ptr = memchr_inv(start, 0, bytes);
        chunk_size = ((ptr == NULL) ? bytes : (ptr - start));
        chunk_size *= GFS2_NBBY;
        BUG_ON(len < chunk_size);
        len -= chunk_size;
        block = gfs2_rbm_to_block(&rbm);
        gfs2_rbm_from_block(&rbm, block + chunk_size);
        n_unaligned = 3;
        if (ptr)
            break;
        n_unaligned = len & 3;
    }

    /* Deal with any bits left over at the end */
    if (n_unaligned)
        gfs2_unaligned_extlen(&rbm, n_unaligned, &len);
out:
    return size - len;
}

static u32 gfs2_bitcount(struct gfs2_rgrpd *rgd, const u8 *buffer,
             unsigned int buflen, u8 state)
{
    const u8 *byte = buffer;
    const u8 *end = buffer + buflen;
    const u8 state1 = state << 2;
    const u8 state2 = state << 4;
    const u8 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;
}

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

    tmp = rgd->rd_data - rgd->rd_free - rgd->rd_dinodes;
    if (count[1] != tmp) {
        if (gfs2_consist_rgrpd(rgd))
            fs_err(sdp, "used data mismatch:  %u != %u\n",
                   count[1], tmp);
        return;
    }

    if (count[2] + count[3] != rgd->rd_dinodes) {
        if (gfs2_consist_rgrpd(rgd))
            fs_err(sdp, "used metadata mismatch:  %u != %u\n",
                   count[2] + count[3], rgd->rd_dinodes);
        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;
}

struct gfs2_rgrpd *gfs2_blk2rgrpd(struct gfs2_sbd *sdp, u64 blk, bool exact)
{
    struct rb_node *n, *next;
    struct gfs2_rgrpd *cur;

    spin_lock(&sdp->sd_rindex_spin);
    n = sdp->sd_rindex_tree.rb_node;
    while (n) {
        cur = rb_entry(n, struct gfs2_rgrpd, rd_node);
        next = NULL;
        if (blk < cur->rd_addr)
            next = n->rb_left;
        else if (blk >= cur->rd_data0 + cur->rd_data)
            next = n->rb_right;
        if (next == NULL) {
            spin_unlock(&sdp->sd_rindex_spin);
            if (exact) {
                if (blk < cur->rd_addr)
                    return NULL;
                if (blk >= cur->rd_data0 + cur->rd_data)
                    return NULL;
            }
            return cur;
        }
        n = next;
    }
    spin_unlock(&sdp->sd_rindex_spin);

    return NULL;
}

struct gfs2_rgrpd *gfs2_rgrpd_get_first(struct gfs2_sbd *sdp)
{
    const struct rb_node *n;
    struct gfs2_rgrpd *rgd;

    spin_lock(&sdp->sd_rindex_spin);
    n = rb_first(&sdp->sd_rindex_tree);
    rgd = rb_entry(n, struct gfs2_rgrpd, rd_node);
    spin_unlock(&sdp->sd_rindex_spin);

    return rgd;
}

struct gfs2_rgrpd *gfs2_rgrpd_get_next(struct gfs2_rgrpd *rgd)
{
    struct gfs2_sbd *sdp = rgd->rd_sbd;
    const struct rb_node *n;

    spin_lock(&sdp->sd_rindex_spin);
    n = rb_next(&rgd->rd_node);
    if (n == NULL)
        n = rb_first(&sdp->sd_rindex_tree);

    if (unlikely(&rgd->rd_node == n)) {
        spin_unlock(&sdp->sd_rindex_spin);
        return NULL;
    }
    rgd = rb_entry(n, struct gfs2_rgrpd, rd_node);
    spin_unlock(&sdp->sd_rindex_spin);
    return rgd;
}

void gfs2_free_clones(struct gfs2_rgrpd *rgd)
{
    int x;

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

int gfs2_rs_alloc(struct gfs2_inode *ip)
{
    struct gfs2_blkreserv *res;

    if (ip->i_res)
        return 0;

    res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
    if (!res)
        return -ENOMEM;

    RB_CLEAR_NODE(&res->rs_node);

    down_write(&ip->i_rw_mutex);
    if (ip->i_res)
        kmem_cache_free(gfs2_rsrv_cachep, res);
    else
        ip->i_res = res;
    up_write(&ip->i_rw_mutex);
    return 0;
}

static void dump_rs(struct seq_file *seq, const struct gfs2_blkreserv *rs)
{
    gfs2_print_dbg(seq, "  B: n:%llu s:%llu b:%u f:%u\n",
               (unsigned long long)rs->rs_inum,
               (unsigned long long)gfs2_rbm_to_block(&rs->rs_rbm),
               rs->rs_rbm.offset, rs->rs_free);
}

static void __rs_deltree(struct gfs2_inode *ip, struct gfs2_blkreserv *rs)
{
    struct gfs2_rgrpd *rgd;

    if (!gfs2_rs_active(rs))
        return;

    rgd = rs->rs_rbm.rgd;
    trace_gfs2_rs(rs, TRACE_RS_TREEDEL);
    rb_erase(&rs->rs_node, &rgd->rd_rstree);
    RB_CLEAR_NODE(&rs->rs_node);

    if (rs->rs_free) {
        /* return reserved blocks to the rgrp and the ip */
        BUG_ON(rs->rs_rbm.rgd->rd_reserved < rs->rs_free);
        rs->rs_rbm.rgd->rd_reserved -= rs->rs_free;
        rs->rs_free = 0;
        clear_bit(GBF_FULL, &rs->rs_rbm.bi->bi_flags);
        smp_mb__after_clear_bit();
    }
}

void gfs2_rs_deltree(struct gfs2_inode *ip, struct gfs2_blkreserv *rs)
{
    struct gfs2_rgrpd *rgd;

    rgd = rs->rs_rbm.rgd;
    if (rgd) {
        spin_lock(&rgd->rd_rsspin);
        __rs_deltree(ip, rs);
        spin_unlock(&rgd->rd_rsspin);
    }
}

void gfs2_rs_delete(struct gfs2_inode *ip)
{
    down_write(&ip->i_rw_mutex);
    if (ip->i_res) {
        gfs2_rs_deltree(ip, ip->i_res);
        BUG_ON(ip->i_res->rs_free);
        kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
        ip->i_res = NULL;
    }
    up_write(&ip->i_rw_mutex);
}

static void return_all_reservations(struct gfs2_rgrpd *rgd)
{
    struct rb_node *n;
    struct gfs2_blkreserv *rs;

    spin_lock(&rgd->rd_rsspin);
    while ((n = rb_first(&rgd->rd_rstree))) {
        rs = rb_entry(n, struct gfs2_blkreserv, rs_node);
        __rs_deltree(NULL, rs);
    }
    spin_unlock(&rgd->rd_rsspin);
}

void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
{
    struct rb_node *n;
    struct gfs2_rgrpd *rgd;
    struct gfs2_glock *gl;

    while ((n = rb_first(&sdp->sd_rindex_tree))) {
        rgd = rb_entry(n, struct gfs2_rgrpd, rd_node);
        gl = rgd->rd_gl;

        rb_erase(n, &sdp->sd_rindex_tree);

        if (gl) {
            spin_lock(&gl->gl_spin);
            gl->gl_object = NULL;
            spin_unlock(&gl->gl_spin);
            gfs2_glock_add_to_lru(gl);
            gfs2_glock_put(gl);
        }

        gfs2_free_clones(rgd);
        kfree(rgd->rd_bits);
        return_all_reservations(rgd);
        kmem_cache_free(gfs2_rgrpd_cachep, rgd);
    }
}

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);
}

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;

        bi->bi_flags = 0;
        /* 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;
}

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)];
    int error, rgrps;

    for (rgrps = 0;; rgrps++) {
        loff_t pos = rgrps * sizeof(struct gfs2_rindex);

        if (pos + sizeof(struct gfs2_rindex) > i_size_read(inode))
            break;
        error = gfs2_internal_read(ip, buf, &pos,
                       sizeof(struct gfs2_rindex));
        if (error != sizeof(struct gfs2_rindex))
            break;
        total_data += be32_to_cpu(((struct gfs2_rindex *)buf)->ri_data);
    }
    return total_data;
}

static int rgd_insert(struct gfs2_rgrpd *rgd)
{
    struct gfs2_sbd *sdp = rgd->rd_sbd;
    struct rb_node **newn = &sdp->sd_rindex_tree.rb_node, *parent = NULL;

    /* Figure out where to put new node */
    while (*newn) {
        struct gfs2_rgrpd *cur = rb_entry(*newn, struct gfs2_rgrpd,
                          rd_node);

        parent = *newn;
        if (rgd->rd_addr < cur->rd_addr)
            newn = &((*newn)->rb_left);
        else if (rgd->rd_addr > cur->rd_addr)
            newn = &((*newn)->rb_right);
        else
            return -EEXIST;
    }

    rb_link_node(&rgd->rd_node, parent, newn);
    rb_insert_color(&rgd->rd_node, &sdp->sd_rindex_tree);
    sdp->sd_rgrps++;
    return 0;
}

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

    if (pos >= i_size_read(&ip->i_inode))
        return 1;

    error = gfs2_internal_read(ip, (char *)&buf, &pos,
                   sizeof(struct gfs2_rindex));

    if (error != sizeof(struct gfs2_rindex))
        return (error == 0) ? 1 : error;

    rgd = kmem_cache_zalloc(gfs2_rgrpd_cachep, GFP_NOFS);
    error = -ENOMEM;
    if (!rgd)
        return error;

    rgd->rd_sbd = sdp;
    rgd->rd_addr = be64_to_cpu(buf.ri_addr);
    rgd->rd_length = be32_to_cpu(buf.ri_length);
    rgd->rd_data0 = be64_to_cpu(buf.ri_data0);
    rgd->rd_data = be32_to_cpu(buf.ri_data);
    rgd->rd_bitbytes = be32_to_cpu(buf.ri_bitbytes);
    spin_lock_init(&rgd->rd_rsspin);

    error = compute_bitstructs(rgd);
    if (error)
        goto fail;

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

    rgd->rd_gl->gl_object = rgd;
    rgd->rd_rgl = (struct gfs2_rgrp_lvb *)rgd->rd_gl->gl_lvb;
    rgd->rd_flags &= ~GFS2_RDF_UPTODATE;
    if (rgd->rd_data > sdp->sd_max_rg_data)
        sdp->sd_max_rg_data = rgd->rd_data;
    spin_lock(&sdp->sd_rindex_spin);
    error = rgd_insert(rgd);
    spin_unlock(&sdp->sd_rindex_spin);
    if (!error)
        return 0;

    error = 0; /* someone else read in the rgrp; free it and ignore it */
    gfs2_glock_put(rgd->rd_gl);

fail:
    kfree(rgd->rd_bits);
    kmem_cache_free(gfs2_rgrpd_cachep, rgd);
    return error;
}

static int gfs2_ri_update(struct gfs2_inode *ip)
{
    struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
    int error;

    do {
        error = read_rindex_entry(ip);
    } while (error == 0);

    if (error < 0)
        return error;

    sdp->sd_rindex_uptodate = 1;
    return 0;
}

int gfs2_rindex_update(struct gfs2_sbd *sdp)
{
    struct gfs2_inode *ip = GFS2_I(sdp->sd_rindex);
    struct gfs2_glock *gl = ip->i_gl;
    struct gfs2_holder ri_gh;
    int error = 0;
    int unlock_required = 0;

    /* Read new copy from disk if we don't have the latest */
    if (!sdp->sd_rindex_uptodate) {
        if (!gfs2_glock_is_locked_by_me(gl)) {
            error = gfs2_glock_nq_init(gl, LM_ST_SHARED, 0, &ri_gh);
            if (error)
                return error;
            unlock_required = 1;
        }
        if (!sdp->sd_rindex_uptodate)
            error = gfs2_ri_update(ip);
        if (unlock_required)
            gfs2_glock_dq_uninit(&ri_gh);
    }

    return error;
}

static void gfs2_rgrp_in(struct gfs2_rgrpd *rgd, const void *buf)
{
    const struct gfs2_rgrp *str = buf;
    u32 rg_flags;

    rg_flags = be32_to_cpu(str->rg_flags);
    rg_flags &= ~GFS2_RDF_MASK;
    rgd->rd_flags &= GFS2_RDF_MASK;
    rgd->rd_flags |= rg_flags;
    rgd->rd_free = be32_to_cpu(str->rg_free);
    rgd->rd_dinodes = be32_to_cpu(str->rg_dinodes);
    rgd->rd_igeneration = be64_to_cpu(str->rg_igeneration);
}

static void gfs2_rgrp_out(struct gfs2_rgrpd *rgd, void *buf)
{
    struct gfs2_rgrp *str = buf;

    str->rg_flags = cpu_to_be32(rgd->rd_flags & ~GFS2_RDF_MASK);
    str->rg_free = cpu_to_be32(rgd->rd_free);
    str->rg_dinodes = cpu_to_be32(rgd->rd_dinodes);
    str->__pad = cpu_to_be32(0);
    str->rg_igeneration = cpu_to_be64(rgd->rd_igeneration);
    memset(&str->rg_reserved, 0, sizeof(str->rg_reserved));
}

static int gfs2_rgrp_lvb_valid(struct gfs2_rgrpd *rgd)
{
    struct gfs2_rgrp_lvb *rgl = rgd->rd_rgl;
    struct gfs2_rgrp *str = (struct gfs2_rgrp *)rgd->rd_bits[0].bi_bh->b_data;

    if (rgl->rl_flags != str->rg_flags || rgl->rl_free != str->rg_free ||
        rgl->rl_dinodes != str->rg_dinodes ||
        rgl->rl_igeneration != str->rg_igeneration)
        return 0;
    return 1;
}

static void gfs2_rgrp_ondisk2lvb(struct gfs2_rgrp_lvb *rgl, const void *buf)
{
    const struct gfs2_rgrp *str = buf;

    rgl->rl_magic = cpu_to_be32(GFS2_MAGIC);
    rgl->rl_flags = str->rg_flags;
    rgl->rl_free = str->rg_free;
    rgl->rl_dinodes = str->rg_dinodes;
    rgl->rl_igeneration = str->rg_igeneration;
    rgl->__pad = 0UL;
}

static void update_rgrp_lvb_unlinked(struct gfs2_rgrpd *rgd, u32 change)
{
    struct gfs2_rgrp_lvb *rgl = rgd->rd_rgl;
    u32 unlinked = be32_to_cpu(rgl->rl_unlinked) + change;
    rgl->rl_unlinked = cpu_to_be32(unlinked);
}

static u32 count_unlinked(struct gfs2_rgrpd *rgd)
{
    struct gfs2_bitmap *bi;
    const u32 length = rgd->rd_length;
    const u8 *buffer = NULL;
    u32 i, goal, count = 0;

    for (i = 0, bi = rgd->rd_bits; i < length; i++, bi++) {
        goal = 0;
        buffer = bi->bi_bh->b_data + bi->bi_offset;
        WARN_ON(!buffer_uptodate(bi->bi_bh));
        while (goal < bi->bi_len * GFS2_NBBY) {
            goal = gfs2_bitfit(buffer, bi->bi_len, goal,
                       GFS2_BLKST_UNLINKED);
            if (goal == BFITNOENT)
                break;
            count++;
            goal++;
        }
    }

    return count;
}


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;

    if (rgd->rd_bits[0].bi_bh != NULL)
        return 0;

    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_flags & GFS2_RDF_UPTODATE)) {
        for (x = 0; x < length; x++)
            clear_bit(GBF_FULL, &rgd->rd_bits[x].bi_flags);
        gfs2_rgrp_in(rgd, (rgd->rd_bits[0].bi_bh)->b_data);
        rgd->rd_flags |= (GFS2_RDF_UPTODATE | GFS2_RDF_CHECK);
        rgd->rd_free_clone = rgd->rd_free;
    }
    if (be32_to_cpu(GFS2_MAGIC) != rgd->rd_rgl->rl_magic) {
        rgd->rd_rgl->rl_unlinked = cpu_to_be32(count_unlinked(rgd));
        gfs2_rgrp_ondisk2lvb(rgd->rd_rgl,
                     rgd->rd_bits[0].bi_bh->b_data);
    }
    else if (sdp->sd_args.ar_rgrplvb) {
        if (!gfs2_rgrp_lvb_valid(rgd)){
            gfs2_consist_rgrpd(rgd);
            error = -EIO;
            goto fail;
        }
        if (rgd->rd_rgl->rl_unlinked == 0)
            rgd->rd_flags &= ~GFS2_RDF_CHECK;
    }
    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);
    }

    return error;
}

int update_rgrp_lvb(struct gfs2_rgrpd *rgd)
{
    u32 rl_flags;

    if (rgd->rd_flags & GFS2_RDF_UPTODATE)
        return 0;

    if (be32_to_cpu(GFS2_MAGIC) != rgd->rd_rgl->rl_magic)
        return gfs2_rgrp_bh_get(rgd);

    rl_flags = be32_to_cpu(rgd->rd_rgl->rl_flags);
    rl_flags &= ~GFS2_RDF_MASK;
    rgd->rd_flags &= GFS2_RDF_MASK;
    rgd->rd_flags |= (rl_flags | GFS2_RDF_UPTODATE | GFS2_RDF_CHECK);
    if (rgd->rd_rgl->rl_unlinked == 0)
        rgd->rd_flags &= ~GFS2_RDF_CHECK;
    rgd->rd_free = be32_to_cpu(rgd->rd_rgl->rl_free);
    rgd->rd_free_clone = rgd->rd_free;
    rgd->rd_dinodes = be32_to_cpu(rgd->rd_rgl->rl_dinodes);
    rgd->rd_igeneration = be64_to_cpu(rgd->rd_rgl->rl_igeneration);
    return 0;
}

int gfs2_rgrp_go_lock(struct gfs2_holder *gh)
{
    struct gfs2_rgrpd *rgd = gh->gh_gl->gl_object;
    struct gfs2_sbd *sdp = rgd->rd_sbd;

    if (gh->gh_flags & GL_SKIP && sdp->sd_args.ar_rgrplvb)
        return 0;
    return gfs2_rgrp_bh_get((struct gfs2_rgrpd *)gh->gh_gl->gl_object);
}

void gfs2_rgrp_go_unlock(struct gfs2_holder *gh)
{
    struct gfs2_rgrpd *rgd = gh->gh_gl->gl_object;
    int x, length = rgd->rd_length;

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

}

int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
                 struct buffer_head *bh,
                 const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed)
{
    struct super_block *sb = sdp->sd_vfs;
    struct block_device *bdev = sb->s_bdev;
    const unsigned int sects_per_blk = sdp->sd_sb.sb_bsize /
                       bdev_logical_block_size(sb->s_bdev);
    u64 blk;
    sector_t start = 0;
    sector_t nr_sects = 0;
    int rv;
    unsigned int x;
    u32 trimmed = 0;
    u8 diff;

    for (x = 0; x < bi->bi_len; x++) {
        const u8 *clone = bi->bi_clone ? bi->bi_clone : bi->bi_bh->b_data;
        clone += bi->bi_offset;
        clone += x;
        if (bh) {
            const u8 *orig = bh->b_data + bi->bi_offset + x;
            diff = ~(*orig | (*orig >> 1)) & (*clone | (*clone >> 1));
        } else {
            diff = ~(*clone | (*clone >> 1));
        }
        diff &= 0x55;
        if (diff == 0)
            continue;
        blk = offset + ((bi->bi_start + x) * GFS2_NBBY);
        blk *= sects_per_blk; /* convert to sectors */
        while(diff) {
            if (diff & 1) {
                if (nr_sects == 0)
                    goto start_new_extent;
                if ((start + nr_sects) != blk) {
                    if (nr_sects >= minlen) {
                        rv = blkdev_issue_discard(bdev,
                            start, nr_sects,
                            GFP_NOFS, 0);
                        if (rv)
                            goto fail;
                        trimmed += nr_sects;
                    }
                    nr_sects = 0;
start_new_extent:
                    start = blk;
                }
                nr_sects += sects_per_blk;
            }
            diff >>= 2;
            blk += sects_per_blk;
        }
    }
    if (nr_sects >= minlen) {
        rv = blkdev_issue_discard(bdev, start, nr_sects, GFP_NOFS, 0);
        if (rv)
            goto fail;
        trimmed += nr_sects;
    }
    if (ptrimmed)
        *ptrimmed = trimmed;
    return 0;

fail:
    if (sdp->sd_args.ar_discard)
        fs_warn(sdp, "error %d on discard request, turning discards off for this filesystem", rv);
    sdp->sd_args.ar_discard = 0;
    return -EIO;
}

int gfs2_fitrim(struct file *filp, void __user *argp)
{
    struct inode *inode = filp->f_dentry->d_inode;
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    struct request_queue *q = bdev_get_queue(sdp->sd_vfs->s_bdev);
    struct buffer_head *bh;
    struct gfs2_rgrpd *rgd;
    struct gfs2_rgrpd *rgd_end;
    struct gfs2_holder gh;
    struct fstrim_range r;
    int ret = 0;
    u64 amt;
    u64 trimmed = 0;
    u64 start, end, minlen;
    unsigned int x;
    unsigned bs_shift = sdp->sd_sb.sb_bsize_shift;

    if (!capable(CAP_SYS_ADMIN))
        return -EPERM;

    if (!blk_queue_discard(q))
        return -EOPNOTSUPP;

    if (copy_from_user(&r, argp, sizeof(r)))
        return -EFAULT;

    ret = gfs2_rindex_update(sdp);
    if (ret)
        return ret;

    start = r.start >> bs_shift;
    end = start + (r.len >> bs_shift);
    minlen = max_t(u64, r.minlen,
               q->limits.discard_granularity) >> bs_shift;

    rgd = gfs2_blk2rgrpd(sdp, start, 0);
    rgd_end = gfs2_blk2rgrpd(sdp, end - 1, 0);

    if (end <= start ||
        minlen > sdp->sd_max_rg_data ||
        start > rgd_end->rd_data0 + rgd_end->rd_data)
        return -EINVAL;

    while (1) {

        ret = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, &gh);
        if (ret)
            goto out;

        if (!(rgd->rd_flags & GFS2_RGF_TRIMMED)) {
            /* Trim each bitmap in the rgrp */
            for (x = 0; x < rgd->rd_length; x++) {
                struct gfs2_bitmap *bi = rgd->rd_bits + x;
                ret = gfs2_rgrp_send_discards(sdp,
                        rgd->rd_data0, NULL, bi, minlen,
                        &amt);
                if (ret) {
                    gfs2_glock_dq_uninit(&gh);
                    goto out;
                }
                trimmed += amt;
            }

            /* Mark rgrp as having been trimmed */
            ret = gfs2_trans_begin(sdp, RES_RG_HDR, 0);
            if (ret == 0) {
                bh = rgd->rd_bits[0].bi_bh;
                rgd->rd_flags |= GFS2_RGF_TRIMMED;
                gfs2_trans_add_bh(rgd->rd_gl, bh, 1);
                gfs2_rgrp_out(rgd, bh->b_data);
                gfs2_rgrp_ondisk2lvb(rgd->rd_rgl, bh->b_data);
                gfs2_trans_end(sdp);
            }
        }
        gfs2_glock_dq_uninit(&gh);

        if (rgd == rgd_end)
            break;

        rgd = gfs2_rgrpd_get_next(rgd);
    }

out:
    r.len = trimmed << 9;
    if (copy_to_user(argp, &r, sizeof(r)))
        return -EFAULT;

    return ret;
}

static void rs_insert(struct gfs2_inode *ip)
{
    struct rb_node **newn, *parent = NULL;
    int rc;
    struct gfs2_blkreserv *rs = ip->i_res;
    struct gfs2_rgrpd *rgd = rs->rs_rbm.rgd;
    u64 fsblock = gfs2_rbm_to_block(&rs->rs_rbm);

    BUG_ON(gfs2_rs_active(rs));

    spin_lock(&rgd->rd_rsspin);
    newn = &rgd->rd_rstree.rb_node;
    while (*newn) {
        struct gfs2_blkreserv *cur =
            rb_entry(*newn, struct gfs2_blkreserv, rs_node);

        parent = *newn;
        rc = rs_cmp(fsblock, rs->rs_free, cur);
        if (rc > 0)
            newn = &((*newn)->rb_right);
        else if (rc < 0)
            newn = &((*newn)->rb_left);
        else {
            spin_unlock(&rgd->rd_rsspin);
            WARN_ON(1);
            return;
        }
    }

    rb_link_node(&rs->rs_node, parent, newn);
    rb_insert_color(&rs->rs_node, &rgd->rd_rstree);

    /* Do our rgrp accounting for the reservation */
    rgd->rd_reserved += rs->rs_free; /* blocks reserved */
    spin_unlock(&rgd->rd_rsspin);
    trace_gfs2_rs(rs, TRACE_RS_INSERT);
}

static void rg_mblk_search(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip,
               unsigned requested)
{
    struct gfs2_rbm rbm = { .rgd = rgd, };
    u64 goal;
    struct gfs2_blkreserv *rs = ip->i_res;
    u32 extlen;
    u32 free_blocks = rgd->rd_free_clone - rgd->rd_reserved;
    int ret;

    extlen = max_t(u32, atomic_read(&rs->rs_sizehint), requested);
    extlen = clamp(extlen, RGRP_RSRV_MINBLKS, free_blocks);
    if ((rgd->rd_free_clone < rgd->rd_reserved) || (free_blocks < extlen))
        return;

    /* Find bitmap block that contains bits for goal block */
    if (rgrp_contains_block(rgd, ip->i_goal))
        goal = ip->i_goal;
    else
        goal = rgd->rd_last_alloc + rgd->rd_data0;

    if (WARN_ON(gfs2_rbm_from_block(&rbm, goal)))
        return;

    ret = gfs2_rbm_find(&rbm, GFS2_BLKST_FREE, extlen, ip, true);
    if (ret == 0) {
        rs->rs_rbm = rbm;
        rs->rs_free = extlen;
        rs->rs_inum = ip->i_no_addr;
        rs_insert(ip);
    }
}

static u64 gfs2_next_unreserved_block(struct gfs2_rgrpd *rgd, u64 block,
                      u32 length,
                      const struct gfs2_inode *ip)
{
    struct gfs2_blkreserv *rs;
    struct rb_node *n;
    int rc;

    spin_lock(&rgd->rd_rsspin);
    n = rgd->rd_rstree.rb_node;
    while (n) {
        rs = rb_entry(n, struct gfs2_blkreserv, rs_node);
        rc = rs_cmp(block, length, rs);
        if (rc < 0)
            n = n->rb_left;
        else if (rc > 0)
            n = n->rb_right;
        else
            break;
    }

    if (n) {
        while ((rs_cmp(block, length, rs) == 0) && (ip->i_res != rs)) {
            block = gfs2_rbm_to_block(&rs->rs_rbm) + rs->rs_free;
            n = n->rb_right;
            if (n == NULL)
                break;
            rs = rb_entry(n, struct gfs2_blkreserv, rs_node);
        }
    }

    spin_unlock(&rgd->rd_rsspin);
    return block;
}

static int gfs2_reservation_check_and_update(struct gfs2_rbm *rbm,
                         const struct gfs2_inode *ip,
                         u32 minext)
{
    u64 block = gfs2_rbm_to_block(rbm);
    u32 extlen = 1;
    u64 nblock;
    int ret;

    /*
     * If we have a minimum extent length, then skip over any extent
     * which is less than the min extent length in size.
     */
    if (minext) {
        extlen = gfs2_free_extlen(rbm, minext);
        nblock = block + extlen;
        if (extlen < minext)
            goto fail;
    }

    /*
     * Check the extent which has been found against the reservations
     * and skip if parts of it are already reserved
     */
    nblock = gfs2_next_unreserved_block(rbm->rgd, block, extlen, ip);
    if (nblock == block)
        return 0;
fail:
    ret = gfs2_rbm_from_block(rbm, nblock);
    if (ret < 0)
        return ret;
    return 1;
}

static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 minext,
             const struct gfs2_inode *ip, bool nowrap)
{
    struct buffer_head *bh;
    struct gfs2_bitmap *initial_bi;
    u32 initial_offset;
    u32 offset;
    u8 *buffer;
    int index;
    int n = 0;
    int iters = rbm->rgd->rd_length;
    int ret;

    /* If we are not starting at the beginning of a bitmap, then we
     * need to add one to the bitmap count to ensure that we search
     * the starting bitmap twice.
     */
    if (rbm->offset != 0)
        iters++;

    while(1) {
        if (test_bit(GBF_FULL, &rbm->bi->bi_flags) &&
            (state == GFS2_BLKST_FREE))
            goto next_bitmap;

        bh = rbm->bi->bi_bh;
        buffer = bh->b_data + rbm->bi->bi_offset;
        WARN_ON(!buffer_uptodate(bh));
        if (state != GFS2_BLKST_UNLINKED && rbm->bi->bi_clone)
            buffer = rbm->bi->bi_clone + rbm->bi->bi_offset;
        initial_offset = rbm->offset;
        offset = gfs2_bitfit(buffer, rbm->bi->bi_len, rbm->offset, state);
        if (offset == BFITNOENT)
            goto bitmap_full;
        rbm->offset = offset;
        if (ip == NULL)
            return 0;

        initial_bi = rbm->bi;
        ret = gfs2_reservation_check_and_update(rbm, ip, minext);
        if (ret == 0)
            return 0;
        if (ret > 0) {
            n += (rbm->bi - initial_bi);
            goto next_iter;
        }
        if (ret == -E2BIG) {
            index = 0;
            rbm->offset = 0;
            n += (rbm->bi - initial_bi);
            goto res_covered_end_of_rgrp;
        }
        return ret;

bitmap_full:    /* Mark bitmap as full and fall through */
        if ((state == GFS2_BLKST_FREE) && initial_offset == 0)
            set_bit(GBF_FULL, &rbm->bi->bi_flags);

next_bitmap:    /* Find next bitmap in the rgrp */
        rbm->offset = 0;
        index = rbm->bi - rbm->rgd->rd_bits;
        index++;
        if (index == rbm->rgd->rd_length)
            index = 0;
res_covered_end_of_rgrp:
        rbm->bi = &rbm->rgd->rd_bits[index];
        if ((index == 0) && nowrap)
            break;
        n++;
next_iter:
        if (n >= iters)
            break;
    }

    return -ENOSPC;
}

static void try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, u64 skip)
{
    u64 block;
    struct gfs2_sbd *sdp = rgd->rd_sbd;
    struct gfs2_glock *gl;
    struct gfs2_inode *ip;
    int error;
    int found = 0;
    struct gfs2_rbm rbm = { .rgd = rgd, .bi = rgd->rd_bits, .offset = 0 };

    while (1) {
        down_write(&sdp->sd_log_flush_lock);
        error = gfs2_rbm_find(&rbm, GFS2_BLKST_UNLINKED, 0, NULL, true);
        up_write(&sdp->sd_log_flush_lock);
        if (error == -ENOSPC)
            break;
        if (WARN_ON_ONCE(error))
            break;

        block = gfs2_rbm_to_block(&rbm);
        if (gfs2_rbm_from_block(&rbm, block + 1))
            break;
        if (*last_unlinked != NO_BLOCK && block <= *last_unlinked)
            continue;
        if (block == skip)
            continue;
        *last_unlinked = block;

        error = gfs2_glock_get(sdp, block, &gfs2_inode_glops, CREATE, &gl);
        if (error)
            continue;

        /* If the inode is already in cache, we can ignore it here
         * because the existing inode disposal code will deal with
         * it when all refs have gone away. Accessing gl_object like
         * this is not safe in general. Here it is ok because we do
         * not dereference the pointer, and we only need an approx
         * answer to whether it is NULL or not.
         */
        ip = gl->gl_object;

        if (ip || queue_work(gfs2_delete_workqueue, &gl->gl_delete) == 0)
            gfs2_glock_put(gl);
        else
            found++;

        /* Limit reclaim to sensible number of tasks */
        if (found > NR_CPUS)
            return;
    }

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

static bool gfs2_select_rgrp(struct gfs2_rgrpd **pos, const struct gfs2_rgrpd *begin)
{
    struct gfs2_rgrpd *rgd = *pos;

    rgd = gfs2_rgrpd_get_next(rgd);
    if (rgd == NULL)
        rgd = gfs2_rgrpd_get_next(NULL);
    *pos = rgd;
    if (rgd != begin) /* If we didn't wrap */
        return true;
    return false;
}

int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)
{
    struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
    struct gfs2_rgrpd *begin = NULL;
    struct gfs2_blkreserv *rs = ip->i_res;
    int error = 0, rg_locked, flags = LM_FLAG_TRY;
    u64 last_unlinked = NO_BLOCK;
    int loops = 0;

    if (sdp->sd_args.ar_rgrplvb)
        flags |= GL_SKIP;
    if (gfs2_assert_warn(sdp, requested))
        return -EINVAL;
    if (gfs2_rs_active(rs)) {
        begin = rs->rs_rbm.rgd;
        flags = 0; /* Yoda: Do or do not. There is no try */
    } else if (ip->i_rgd && rgrp_contains_block(ip->i_rgd, ip->i_goal)) {
        rs->rs_rbm.rgd = begin = ip->i_rgd;
    } else {
        rs->rs_rbm.rgd = begin = gfs2_blk2rgrpd(sdp, ip->i_goal, 1);
    }
    if (rs->rs_rbm.rgd == NULL)
        return -EBADSLT;

    while (loops < 3) {
        rg_locked = 1;

        if (!gfs2_glock_is_locked_by_me(rs->rs_rbm.rgd->rd_gl)) {
            rg_locked = 0;
            error = gfs2_glock_nq_init(rs->rs_rbm.rgd->rd_gl,
                           LM_ST_EXCLUSIVE, flags,
                           &rs->rs_rgd_gh);
            if (error == GLR_TRYFAILED)
                goto next_rgrp;
            if (unlikely(error))
                return error;
            if (sdp->sd_args.ar_rgrplvb) {
                error = update_rgrp_lvb(rs->rs_rbm.rgd);
                if (unlikely(error)) {
                    gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
                    return error;
                }
            }
        }

        /* Skip unuseable resource groups */
        if (rs->rs_rbm.rgd->rd_flags & (GFS2_RGF_NOALLOC | GFS2_RDF_ERROR))
            goto skip_rgrp;

        if (sdp->sd_args.ar_rgrplvb)
            gfs2_rgrp_bh_get(rs->rs_rbm.rgd);

        /* Get a reservation if we don't already have one */
        if (!gfs2_rs_active(rs))
            rg_mblk_search(rs->rs_rbm.rgd, ip, requested);

        /* Skip rgrps when we can't get a reservation on first pass */
        if (!gfs2_rs_active(rs) && (loops < 1))
            goto check_rgrp;

        /* If rgrp has enough free space, use it */
        if (rs->rs_rbm.rgd->rd_free_clone >= requested) {
            ip->i_rgd = rs->rs_rbm.rgd;
            return 0;
        }

        /* Drop reservation, if we couldn't use reserved rgrp */
        if (gfs2_rs_active(rs))
            gfs2_rs_deltree(ip, rs);
check_rgrp:
        /* Check for unlinked inodes which can be reclaimed */
        if (rs->rs_rbm.rgd->rd_flags & GFS2_RDF_CHECK)
            try_rgrp_unlink(rs->rs_rbm.rgd, &last_unlinked,
                    ip->i_no_addr);
skip_rgrp:
        /* Unlock rgrp if required */
        if (!rg_locked)
            gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
next_rgrp:
        /* Find the next rgrp, and continue looking */
        if (gfs2_select_rgrp(&rs->rs_rbm.rgd, begin))
            continue;

        /* If we've scanned all the rgrps, but found no free blocks
         * then this checks for some less likely conditions before
         * trying again.
         */
        flags &= ~LM_FLAG_TRY;
        loops++;
        /* Check that fs hasn't grown if writing to rindex */
        if (ip == GFS2_I(sdp->sd_rindex) && !sdp->sd_rindex_uptodate) {
            error = gfs2_ri_update(ip);
            if (error)
                return error;
        }
        /* Flushing the log may release space */
        if (loops == 2)
            gfs2_log_flush(sdp, NULL);
    }

    return -ENOSPC;
}

void gfs2_inplace_release(struct gfs2_inode *ip)
{
    struct gfs2_blkreserv *rs = ip->i_res;

    if (rs->rs_rgd_gh.gh_gl)
        gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
}

static unsigned char gfs2_get_block_type(struct gfs2_rgrpd *rgd, u64 block)
{
    struct gfs2_rbm rbm = { .rgd = rgd, };
    int ret;

    ret = gfs2_rbm_from_block(&rbm, block);
    WARN_ON_ONCE(ret != 0);

    return gfs2_testbit(&rbm);
}


static void gfs2_alloc_extent(const struct gfs2_rbm *rbm, bool dinode,
                 unsigned int *n)
{
    struct gfs2_rbm pos = { .rgd = rbm->rgd, };
    const unsigned int elen = *n;
    u64 block;
    int ret;

    *n = 1;
    block = gfs2_rbm_to_block(rbm);
    gfs2_trans_add_bh(rbm->rgd->rd_gl, rbm->bi->bi_bh, 1);
    gfs2_setbit(rbm, true, dinode ? GFS2_BLKST_DINODE : GFS2_BLKST_USED);
    block++;
    while (*n < elen) {
        ret = gfs2_rbm_from_block(&pos, block);
        if (ret || gfs2_testbit(&pos) != GFS2_BLKST_FREE)
            break;
        gfs2_trans_add_bh(pos.rgd->rd_gl, pos.bi->bi_bh, 1);
        gfs2_setbit(&pos, true, GFS2_BLKST_USED);
        (*n)++;
        block++;
    }
}

static struct gfs2_rgrpd *rgblk_free(struct gfs2_sbd *sdp, u64 bstart,
                     u32 blen, unsigned char new_state)
{
    struct gfs2_rbm rbm;

    rbm.rgd = gfs2_blk2rgrpd(sdp, bstart, 1);
    if (!rbm.rgd) {
        if (gfs2_consist(sdp))
            fs_err(sdp, "block = %llu\n", (unsigned long long)bstart);
        return NULL;
    }

    while (blen--) {
        gfs2_rbm_from_block(&rbm, bstart);
        bstart++;
        if (!rbm.bi->bi_clone) {
            rbm.bi->bi_clone = kmalloc(rbm.bi->bi_bh->b_size,
                           GFP_NOFS | __GFP_NOFAIL);
            memcpy(rbm.bi->bi_clone + rbm.bi->bi_offset,
                   rbm.bi->bi_bh->b_data + rbm.bi->bi_offset,
                   rbm.bi->bi_len);
        }
        gfs2_trans_add_bh(rbm.rgd->rd_gl, rbm.bi->bi_bh, 1);
        gfs2_setbit(&rbm, false, new_state);
    }

    return rbm.rgd;
}

int gfs2_rgrp_dump(struct seq_file *seq, const struct gfs2_glock *gl)
{
    struct gfs2_rgrpd *rgd = gl->gl_object;
    struct gfs2_blkreserv *trs;
    const struct rb_node *n;

    if (rgd == NULL)
        return 0;
    gfs2_print_dbg(seq, " R: n:%llu f:%02x b:%u/%u i:%u r:%u\n",
               (unsigned long long)rgd->rd_addr, rgd->rd_flags,
               rgd->rd_free, rgd->rd_free_clone, rgd->rd_dinodes,
               rgd->rd_reserved);
    spin_lock(&rgd->rd_rsspin);
    for (n = rb_first(&rgd->rd_rstree); n; n = rb_next(&trs->rs_node)) {
        trs = rb_entry(n, struct gfs2_blkreserv, rs_node);
        dump_rs(seq, trs);
    }
    spin_unlock(&rgd->rd_rsspin);
    return 0;
}

static void gfs2_rgrp_error(struct gfs2_rgrpd *rgd)
{
    struct gfs2_sbd *sdp = rgd->rd_sbd;
    fs_warn(sdp, "rgrp %llu has an error, marking it readonly until umount\n",
        (unsigned long long)rgd->rd_addr);
    fs_warn(sdp, "umount on all nodes and run fsck.gfs2 to fix the error\n");
    gfs2_rgrp_dump(NULL, rgd->rd_gl);
    rgd->rd_flags |= GFS2_RDF_ERROR;
}

static void gfs2_adjust_reservation(struct gfs2_inode *ip,
                    const struct gfs2_rbm *rbm, unsigned len)
{
    struct gfs2_blkreserv *rs = ip->i_res;
    struct gfs2_rgrpd *rgd = rbm->rgd;
    unsigned rlen;
    u64 block;
    int ret;

    spin_lock(&rgd->rd_rsspin);
    if (gfs2_rs_active(rs)) {
        if (gfs2_rbm_eq(&rs->rs_rbm, rbm)) {
            block = gfs2_rbm_to_block(rbm);
            ret = gfs2_rbm_from_block(&rs->rs_rbm, block + len);
            rlen = min(rs->rs_free, len);
            rs->rs_free -= rlen;
            rgd->rd_reserved -= rlen;
            trace_gfs2_rs(rs, TRACE_RS_CLAIM);
            if (rs->rs_free && !ret)
                goto out;
        }
        __rs_deltree(ip, rs);
    }
out:
    spin_unlock(&rgd->rd_rsspin);
}

int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
              bool dinode, u64 *generation)
{
    struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
    struct buffer_head *dibh;
    struct gfs2_rbm rbm = { .rgd = ip->i_rgd, };
    unsigned int ndata;
    u64 goal;
    u64 block; /* block, within the file system scope */
    int error;

    if (gfs2_rs_active(ip->i_res))
        goal = gfs2_rbm_to_block(&ip->i_res->rs_rbm);
    else if (!dinode && rgrp_contains_block(rbm.rgd, ip->i_goal))
        goal = ip->i_goal;
    else
        goal = rbm.rgd->rd_last_alloc + rbm.rgd->rd_data0;

    gfs2_rbm_from_block(&rbm, goal);
    error = gfs2_rbm_find(&rbm, GFS2_BLKST_FREE, 0, ip, false);

    if (error == -ENOSPC) {
        gfs2_rbm_from_block(&rbm, goal);
        error = gfs2_rbm_find(&rbm, GFS2_BLKST_FREE, 0, NULL, false);
    }

    /* Since all blocks are reserved in advance, this shouldn't happen */
    if (error) {
        fs_warn(sdp, "inum=%llu error=%d, nblocks=%u, full=%d\n",
            (unsigned long long)ip->i_no_addr, error, *nblocks,
            test_bit(GBF_FULL, &rbm.rgd->rd_bits->bi_flags));
        goto rgrp_error;
    }

    gfs2_alloc_extent(&rbm, dinode, nblocks);
    block = gfs2_rbm_to_block(&rbm);
    rbm.rgd->rd_last_alloc = block - rbm.rgd->rd_data0;
    if (gfs2_rs_active(ip->i_res))
        gfs2_adjust_reservation(ip, &rbm, *nblocks);
    ndata = *nblocks;
    if (dinode)
        ndata--;

    if (!dinode) {
        ip->i_goal = block + ndata - 1;
        error = gfs2_meta_inode_buffer(ip, &dibh);
        if (error == 0) {
            struct gfs2_dinode *di =
                (struct gfs2_dinode *)dibh->b_data;
            gfs2_trans_add_bh(ip->i_gl, dibh, 1);
            di->di_goal_meta = di->di_goal_data =
                cpu_to_be64(ip->i_goal);
            brelse(dibh);
        }
    }
    if (rbm.rgd->rd_free < *nblocks) {
        printk(KERN_WARNING "nblocks=%u\n", *nblocks);
        goto rgrp_error;
    }

    rbm.rgd->rd_free -= *nblocks;
    if (dinode) {
        rbm.rgd->rd_dinodes++;
        *generation = rbm.rgd->rd_igeneration++;
        if (*generation == 0)
            *generation = rbm.rgd->rd_igeneration++;
    }

    gfs2_trans_add_bh(rbm.rgd->rd_gl, rbm.rgd->rd_bits[0].bi_bh, 1);
    gfs2_rgrp_out(rbm.rgd, rbm.rgd->rd_bits[0].bi_bh->b_data);
    gfs2_rgrp_ondisk2lvb(rbm.rgd->rd_rgl, rbm.rgd->rd_bits[0].bi_bh->b_data);

    gfs2_statfs_change(sdp, 0, -(s64)*nblocks, dinode ? 1 : 0);
    if (dinode)
        gfs2_trans_add_unrevoke(sdp, block, 1);

    /*
     * This needs reviewing to see why we cannot do the quota change
     * at this point in the dinode case.
     */
    if (ndata)
        gfs2_quota_change(ip, ndata, ip->i_inode.i_uid,
                  ip->i_inode.i_gid);

    rbm.rgd->rd_free_clone -= *nblocks;
    trace_gfs2_block_alloc(ip, rbm.rgd, block, *nblocks,
                   dinode ? GFS2_BLKST_DINODE : GFS2_BLKST_USED);
    *bn = block;
    return 0;

rgrp_error:
    gfs2_rgrp_error(rbm.rgd);
    return -EIO;
}

void __gfs2_free_blocks(struct gfs2_inode *ip, u64 bstart, u32 blen, int meta)
{
    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;
    trace_gfs2_block_alloc(ip, rgd, bstart, blen, GFS2_BLKST_FREE);
    rgd->rd_free += blen;
    rgd->rd_flags &= ~GFS2_RGF_TRIMMED;
    gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
    gfs2_rgrp_out(rgd, rgd->rd_bits[0].bi_bh->b_data);
    gfs2_rgrp_ondisk2lvb(rgd->rd_rgl, rgd->rd_bits[0].bi_bh->b_data);

    /* Directories keep their data in the metadata address space */
    if (meta || ip->i_depth)
        gfs2_meta_wipe(ip, bstart, blen);
}

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

    __gfs2_free_blocks(ip, bstart, blen, 1);
    gfs2_statfs_change(sdp, 0, +blen, 0);
    gfs2_quota_change(ip, -(s64)blen, ip->i_inode.i_uid, ip->i_inode.i_gid);
}

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;
    trace_gfs2_block_alloc(ip, rgd, blkno, 1, GFS2_BLKST_UNLINKED);
    gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
    gfs2_rgrp_out(rgd, rgd->rd_bits[0].bi_bh->b_data);
    gfs2_rgrp_ondisk2lvb(rgd->rd_rgl, rgd->rd_bits[0].bi_bh->b_data);
    update_rgrp_lvb_unlinked(rgd, 1);
}

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_dinodes)
        gfs2_consist_rgrpd(rgd);
    rgd->rd_dinodes--;
    rgd->rd_free++;

    gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
    gfs2_rgrp_out(rgd, rgd->rd_bits[0].bi_bh->b_data);
    gfs2_rgrp_ondisk2lvb(rgd->rd_rgl, rgd->rd_bits[0].bi_bh->b_data);
    update_rgrp_lvb_unlinked(rgd, -1);

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


void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip)
{
    gfs2_free_uninit_di(rgd, ip->i_no_addr);
    trace_gfs2_block_alloc(ip, rgd, ip->i_no_addr, 1, GFS2_BLKST_FREE);
    gfs2_quota_change(ip, -1, ip->i_inode.i_uid, ip->i_inode.i_gid);
    gfs2_meta_wipe(ip, ip->i_no_addr, 1);
}

int gfs2_check_blk_type(struct gfs2_sbd *sdp, u64 no_addr, unsigned int type)
{
    struct gfs2_rgrpd *rgd;
    struct gfs2_holder rgd_gh;
    int error = -EINVAL;

    rgd = gfs2_blk2rgrpd(sdp, no_addr, 1);
    if (!rgd)
        goto fail;

    error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_SHARED, 0, &rgd_gh);
    if (error)
        goto fail;

    if (gfs2_get_block_type(rgd, no_addr) != type)
        error = -ESTALE;

    gfs2_glock_dq_uninit(&rgd_gh);
fail:
    return error;
}

void gfs2_rlist_add(struct gfs2_inode *ip, struct gfs2_rgrp_list *rlist,
            u64 block)
{
    struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
    struct gfs2_rgrpd *rgd;
    struct gfs2_rgrpd **tmp;
    unsigned int new_space;
    unsigned int x;

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

    if (ip->i_rgd && rgrp_contains_block(ip->i_rgd, block))
        rgd = ip->i_rgd;
    else
        rgd = gfs2_blk2rgrpd(sdp, block, 1);
    if (!rgd) {
        fs_err(sdp, "rlist_add: no rgrp for block %llu\n", (unsigned long long)block);
        return;
    }
    ip->i_rgd = rgd;

    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;
}

void gfs2_rlist_alloc(struct gfs2_rgrp_list *rlist, unsigned int state)
{
    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, 0,
                &rlist->rl_ghs[x]);
}

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);
        rlist->rl_ghs = NULL;
    }
}