/*
   * 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 u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,

  			unsigned char old_state,

  			struct gfs2_bitmap **rbi);

  /**
   * 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 inline void gfs2_setbit(struct gfs2_rgrpd *rgd, unsigned char *buf1,
  			       unsigned char *buf2, unsigned int offset,

  			       struct gfs2_bitmap *bi, u32 block,

  			       unsigned char new_state)

  {

  	unsigned char *byte1, *byte2, *end, cur_state;

  	unsigned int buflen = bi->bi_len;

  	const unsigned int bit = (block % GFS2_NBBY) * GFS2_BIT_SIZE;

  	byte1 = buf1 + offset + (block / GFS2_NBBY);
  	end = buf1 + 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%llx old_state=%d, "
  		       "new_state=%d
  ",
  		       (unsigned long long)block, cur_state, new_state);
  		printk(KERN_WARNING "GFS2: rgrp=0x%llx bi_start=0x%lx
  ",
  		       (unsigned long long)rgd->rd_addr,
  		       (unsigned long)bi->bi_start);
  		printk(KERN_WARNING "GFS2: bi_offset=0x%lx bi_len=0x%lx
  ",
  		       (unsigned long)bi->bi_offset,
  		       (unsigned long)bi->bi_len);
  		dump_stack();

  		gfs2_consist_rgrpd(rgd);

  		return;
  	}
  	*byte1 ^= (cur_state ^ new_state) << bit;
  
  	if (buf2) {
  		byte2 = buf2 + offset + (block / GFS2_NBBY);
  		cur_state = (*byte2 >> bit) & GFS2_BIT_MASK;
  		*byte2 ^= (cur_state ^ new_state) << bit;
  	}

  }
  
  /**
   * 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 inline unsigned char gfs2_testbit(struct gfs2_rgrpd *rgd,
  					 const unsigned char *buffer,
  					 unsigned int buflen, u32 block)

  {

  	const unsigned char *byte, *end;
  	unsigned char 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_bit_search
   * @ptr: Pointer to bitmap data
   * @mask: Mask to use (normally 0x55555.... but adjusted for search start)
   * @state: The state we are searching for
   *
   * We xor the bitmap data with a patter which is the bitwise opposite
   * of what we are looking for, this gives rise to a pattern of ones
   * wherever there is a match. Since we have two bits per entry, we
   * take this pattern, shift it down by one place and then and it with
   * the original. All the even bit positions (0,2,4, etc) then represent
   * successful matches, so we mask with 0x55555..... to remove the unwanted
   * odd bit positions.
   *
   * This allows searching of a whole u64 at once (32 blocks) with a
   * single test (on 64 bit arches).
   */
  
  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;
  }
  
  /**

   * 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

   * @len: the length (in bytes) of the buffer

   * @goal: start search at this block's bit-pair (within @buffer)

   * @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, but
   * headers are always a multiple of 64 bits long so that the buffer is
   * always aligned to a 64 bit boundary.
   *
   * The size of the buffer is in bytes, but is it assumed that it is

   * always ok to read a complete multiple of 64 bits at the end

   * of the block in case the end is no aligned to a natural boundary.

   *
   * Return: the block number (bitmap buffer scope) that was found
   */

  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;
  
  	BUG_ON(state > 3);
  
  	/* 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;

  }
  
  /**
   * 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, 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;
  }

  /**
   * 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_free) {

  		if (gfs2_consist_rgrpd(rgd))
  			fs_err(sdp, "free data mismatch:  %u != %u
  ",

  			       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
  ",
  			       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
  ",

  			       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;

  }
  
  /**
   * 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 rb_node **newn;
  	struct gfs2_rgrpd *cur;

  
  	spin_lock(&sdp->sd_rindex_spin);

  	newn = &sdp->sd_rindex_tree.rb_node;

  	while (*newn) {

  		cur = rb_entry(*newn, struct gfs2_rgrpd, rd_node);

  		if (blk < cur->rd_addr)
  			newn = &((*newn)->rb_left);

  		else if (blk >= cur->rd_data0 + cur->rd_data)

  			newn = &((*newn)->rb_right);
  		else {

  			spin_unlock(&sdp->sd_rindex_spin);

  			return cur;

  		}
  	}

  	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)
  {

  	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;

  }
  
  /**
   * 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)
  {

  	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;
  	}
  }
  
  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);

  		kmem_cache_free(gfs2_rgrpd_cachep, rgd);

  	}
  }

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

  		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
  ",
  			       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) > i_size_read(inode))

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

  /**

   * read_rindex_entry - Pull in a new resource index entry from the disk

   * @gl: The glock covering the rindex inode
   *

   * Returns: 0 on success, > 0 on EOF, 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);

  	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, ra_state, (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);

  	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_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);
  	rgd_insert(rgd);
  	sdp->sd_rgrps++;
  	spin_unlock(&sdp->sd_rindex_spin);
  	return error;
  
  fail:
  	kfree(rgd->rd_bits);
  	kmem_cache_free(gfs2_rgrpd_cachep, rgd);

  	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;

  	int error;

  	file_ra_state_init(&ra_state, inode->i_mapping);

  	do {

  		error = read_rindex_entry(ip, &ra_state);

  	} while (error == 0);
  
  	if (error < 0)
  		return error;

  	sdp->sd_rindex_uptodate = 1;

  	return 0;
  }

  /**

   * gfs2_rindex_update - Update the rindex if required

   * @sdp: The GFS2 superblock

   *
   * 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 succeess, error code otherwise

   */

  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;

  
  	/* Read new copy from disk if we don't have the latest */

  	if (!sdp->sd_rindex_uptodate) {

  		mutex_lock(&sdp->sd_rindex_mutex);

  		error = gfs2_glock_nq_init(gl, LM_ST_SHARED, 0, &ri_gh);
  		if (error)
  			return error;
  		if (!sdp->sd_rindex_uptodate)

  			error = gfs2_ri_update(ip);

  		gfs2_glock_dq_uninit(&ri_gh);

  		mutex_unlock(&sdp->sd_rindex_mutex);

  	}

  	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));
  }

  /**

   * gfs2_rgrp_go_lock - 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_go_lock(struct gfs2_holder *gh)

  {

  	struct gfs2_rgrpd *rgd = gh->gh_gl->gl_object;

  	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;

  	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;

  	}

  	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;
  }

  /**

   * gfs2_rgrp_go_unlock - Release RG bitmaps read in with gfs2_rgrp_bh_get()

   * @rgd: the struct gfs2_rgrpd describing the RG to read in
   *
   */

  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;

  		brelse(bi->bi_bh);
  		bi->bi_bh = NULL;
  	}

  }

  void gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
  			     struct buffer_head *bh,
  			     const struct gfs2_bitmap *bi)

  {
  	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;
  
  	for (x = 0; x < bi->bi_len; x++) {

  		const u8 *orig = bh->b_data + bi->bi_offset + x;

  		const u8 *clone = bi->bi_clone + bi->bi_offset + x;
  		u8 diff = ~(*orig | (*orig >> 1)) & (*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) {
  					rv = blkdev_issue_discard(bdev, start,

  							    nr_sects, GFP_NOFS,

  							    0);

  					if (rv)
  						goto fail;
  					nr_sects = 0;
  start_new_extent:
  					start = blk;
  				}
  				nr_sects += sects_per_blk;
  			}
  			diff >>= 2;
  			blk += sects_per_blk;
  		}
  	}
  	if (nr_sects) {

  		rv = blkdev_issue_discard(bdev, start, nr_sects, GFP_NOFS, 0);

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

  /**

   * gfs2_qadata_get - get the struct gfs2_qadata structure for an inode

   * @ip: the incore GFS2 inode structure
   *

   * Returns: the struct gfs2_qadata

   */

  struct gfs2_qadata *gfs2_qadata_get(struct gfs2_inode *ip)

  {

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

  	BUG_ON(ip->i_qadata != NULL);
  	ip->i_qadata = kzalloc(sizeof(struct gfs2_qadata), GFP_NOFS);

  	error = gfs2_rindex_update(sdp);
  	if (error)
  		fs_warn(sdp, "rindex update returns %d
  ", error);

  	return ip->i_qadata;
  }
  
  /**
   * gfs2_blkrsv_get - get the struct gfs2_blkreserv structure for an inode
   * @ip: the incore GFS2 inode structure
   *
   * Returns: the struct gfs2_qadata
   */
  
  static struct gfs2_blkreserv *gfs2_blkrsv_get(struct gfs2_inode *ip)
  {
  	BUG_ON(ip->i_res != NULL);
  	ip->i_res = kzalloc(sizeof(struct gfs2_blkreserv), GFP_NOFS);
  	return ip->i_res;

  }
  
  /**

   * try_rgrp_fit - See if a given reservation will fit in a given RG
   * @rgd: the RG data

   * @ip: the inode

   *
   * If there's room for the requested blocks to be allocated from the RG:

   *
   * Returns: 1 on success (it fits), 0 on failure (it doesn't fit)
   */

  static int try_rgrp_fit(const struct gfs2_rgrpd *rgd, const struct gfs2_inode *ip)

  {

  	const struct gfs2_blkreserv *rs = ip->i_res;

  	if (rgd->rd_flags & (GFS2_RGF_NOALLOC | GFS2_RDF_ERROR))

  		return 0;

  	if (rgd->rd_free_clone >= rs->rs_requested)

  		return 1;

  	return 0;

  }

  static inline u32 gfs2_bi2rgd_blk(struct gfs2_bitmap *bi, u32 blk)
  {
  	return (bi->bi_start * GFS2_NBBY) + blk;
  }

  /**

   * try_rgrp_unlink - Look for any unlinked, allocated, but unused inodes
   * @rgd: The rgrp
   *

   * Returns: 0 if no error
   *          The inode, if one has been found, in inode.

   */

  static void try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, u64 skip)

  {

  	u32 goal = 0, block;

  	u64 no_addr;

  	struct gfs2_sbd *sdp = rgd->rd_sbd;

  	struct gfs2_glock *gl;
  	struct gfs2_inode *ip;
  	int error;
  	int found = 0;

  	struct gfs2_bitmap *bi;

  	while (goal < rgd->rd_data) {

  		down_write(&sdp->sd_log_flush_lock);

  		block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED, &bi);

  		up_write(&sdp->sd_log_flush_lock);

  		if (block == BFITNOENT)

  			break;

  
  		block = gfs2_bi2rgd_blk(bi, block);

  		/* rgblk_search can return a block < goal, so we need to
  		   keep it marching forward. */
  		no_addr = block + rgd->rd_data0;

  		goal = max(block + 1, goal + 1);

  		if (*last_unlinked != NO_BLOCK && no_addr <= *last_unlinked)

  			continue;

  		if (no_addr == skip)
  			continue;

  		*last_unlinked = no_addr;

  
  		error = gfs2_glock_get(sdp, no_addr, &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;

  }
  
  /**

   * 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 int get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)

  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct gfs2_rgrpd *rgd, *begin = NULL;

  	struct gfs2_blkreserv *rs = ip->i_res;

  	int error, rg_locked, flags = LM_FLAG_TRY;

  	int loops = 0;

  	if (ip->i_rgd && rgrp_contains_block(ip->i_rgd, ip->i_goal))
  		rgd = begin = ip->i_rgd;
  	else
  		rgd = begin = gfs2_blk2rgrpd(sdp, ip->i_goal);

  	if (rgd == NULL)
  		return -EBADSLT;
  
  	while (loops < 3) {

  		rg_locked = 0;
  
  		if (gfs2_glock_is_locked_by_me(rgd->rd_gl)) {
  			rg_locked = 1;
  			error = 0;
  		} else {
  			error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE,

  						   flags, &rs->rs_rgd_gh);

  		}

  		switch (error) {
  		case 0:

  			if (try_rgrp_fit(rgd, ip)) {
  				ip->i_rgd = rgd;

  				return 0;

  			}

  			if (rgd->rd_flags & GFS2_RDF_CHECK)
  				try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr);

  			if (!rg_locked)

  				gfs2_glock_dq_uninit(&rs->rs_rgd_gh);

  			/* fall through */

  		case GLR_TRYFAILED:

  			rgd = gfs2_rgrpd_get_next(rgd);

  			if (rgd == begin) {
  				flags = 0;

  				loops++;

  			}

  			break;

  		default:

  			return error;

  		}

  	}

  	return -ENOSPC;

  }

  static void gfs2_blkrsv_put(struct gfs2_inode *ip)
  {
  	BUG_ON(ip->i_res == NULL);
  	kfree(ip->i_res);
  	ip->i_res = NULL;
  }

  /**

   * gfs2_inplace_reserve - Reserve space in the filesystem

   * @ip: the inode to reserve space for
   *
   * Returns: errno
   */

  int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)

  {

  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

  	struct gfs2_blkreserv *rs;

  	int error = 0;

  	u64 last_unlinked = NO_BLOCK;
  	int tries = 0;

  	rs = gfs2_blkrsv_get(ip);
  	if (!rs)
  		return -ENOMEM;
  
  	rs->rs_requested = requested;
  	if (gfs2_assert_warn(sdp, requested)) {
  		error = -EINVAL;
  		goto out;
  	}

  	do {
  		error = get_local_rgrp(ip, &last_unlinked);

  		if (error != -ENOSPC)
  			break;
  		/* 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)
  				break;
  			continue;

  		}

  		/* Flushing the log may release space */
  		gfs2_log_flush(sdp, NULL);
  	} while (tries++ < 3);

  out:
  	if (error)
  		gfs2_blkrsv_put(ip);

  	return error;

  }
  
  /**
   * 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_blkreserv *rs = ip->i_res;

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

  	gfs2_blkrsv_put(ip);

  }
  
  /**
   * 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_*)
   */

  static 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 @state

   * @rgd: the resource group descriptor
   * @goal: the goal block within the RG (start here to search for avail block)

   * @state: GFS2_BLKST_XXX the before-allocation state to find

   * @dinode: TRUE if the first block we allocate is for a dinode

   * @rbi: address of the pointer to the bitmap containing the block found

   *

   * Walk rgrp's bitmap to find bits that represent a block in @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 is just within rgrp, not the whole filesystem.
   * Scope of @returned block is just within bitmap, not the whole filesystem.

   *

   * Returns: the block number found relative to the bitmap rbi

   */

  static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,

  			unsigned char state,

  			struct gfs2_bitmap **rbi)

  {
  	struct gfs2_bitmap *bi = NULL;

  	const u32 length = rgd->rd_length;

  	u32 blk = BFITNOENT;

  	unsigned int buf, x;

  	const u8 *buffer = NULL;

  	*rbi = NULL;

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

  		/* Convert scope of "goal" from rgrp-wide to within found bit block */
  		if (goal < (bi->bi_start + bi->bi_len) * GFS2_NBBY) {
  			goal -= bi->bi_start * GFS2_NBBY;
  			goto do_search;
  		}

  	}

  	buf = 0;
  	goal = 0;

  do_search:

  	/* 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++) {

  		bi = rgd->rd_bits + buf;
  
  		if (test_bit(GBF_FULL, &bi->bi_flags) &&

  		    (state == GFS2_BLKST_FREE))

  			goto skip;

  		/* The GFS2_BLKST_UNLINKED state doesn't apply to the clone
  		   bitmaps, so we must search the originals for that. */

  		buffer = bi->bi_bh->b_data + bi->bi_offset;

  		WARN_ON(!buffer_uptodate(bi->bi_bh));

  		if (state != GFS2_BLKST_UNLINKED && bi->bi_clone)

  			buffer = bi->bi_clone + bi->bi_offset;

  		blk = gfs2_bitfit(buffer, bi->bi_len, goal, state);

  		if (blk != BFITNOENT)
  			break;

  		if ((goal == 0) && (state == GFS2_BLKST_FREE))

  			set_bit(GBF_FULL, &bi->bi_flags);

  		/* Try next bitmap block (wrap back to rgrp header if at end) */

  skip:
  		buf++;
  		buf %= length;

  		goal = 0;
  	}

  	if (blk != BFITNOENT)
  		*rbi = bi;

  	return blk;
  }

  /**
   * gfs2_alloc_extent - allocate an extent from a given bitmap
   * @rgd: the resource group descriptor
   * @bi: the bitmap within the rgrp
   * @blk: the block within the bitmap
   * @dinode: TRUE if the first block we allocate is for a dinode
   * @n: The extent length
   *
   * Add the found bitmap buffer to the transaction.
   * Set the found bits to @new_state to change block's allocation state.
   * Returns: starting block number of the extent (fs scope)
   */
  static u64 gfs2_alloc_extent(struct gfs2_rgrpd *rgd, struct gfs2_bitmap *bi,
  			     u32 blk, bool dinode, unsigned int *n)
  {
  	const unsigned int elen = *n;
  	u32 goal;
  	const u8 *buffer = NULL;

  	*n = 0;

  	buffer = bi->bi_bh->b_data + bi->bi_offset;

  	gfs2_trans_add_bh(rgd->rd_gl, bi->bi_bh, 1);
  	gfs2_setbit(rgd, bi->bi_bh->b_data, bi->bi_clone, bi->bi_offset,

  		    bi, blk, dinode ? GFS2_BLKST_DINODE : GFS2_BLKST_USED);

  	(*n)++;

  	goal = blk;
  	while (*n < elen) {
  		goal++;
  		if (goal >= (bi->bi_len * GFS2_NBBY))
  			break;
  		if (gfs2_testbit(rgd, buffer, bi->bi_len, goal) !=
  		    GFS2_BLKST_FREE)
  			break;

  		gfs2_setbit(rgd, bi->bi_bh->b_data, bi->bi_clone, bi->bi_offset,

  			    bi, goal, GFS2_BLKST_USED);

  		(*n)++;

  	}

  	blk = gfs2_bi2rgd_blk(bi, blk);

  	rgd->rd_last_alloc = blk + *n - 1;

  	return rgd->rd_data0 + 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
  ", (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, NULL, bi->bi_offset,

  			    bi, buf_blk, new_state);

  	}
  
  	return rgd;
  }
  
  /**

   * gfs2_rgrp_dump - print out an rgrp
   * @seq: The iterator
   * @gl: The glock in question
   *
   */
  
  int gfs2_rgrp_dump(struct seq_file *seq, const struct gfs2_glock *gl)
  {
  	const struct gfs2_rgrpd *rgd = gl->gl_object;
  	if (rgd == NULL)
  		return 0;
  	gfs2_print_dbg(seq, " R: n:%llu f:%02x b:%u/%u i:%u
  ",
  		       (unsigned long long)rgd->rd_addr, rgd->rd_flags,
  		       rgd->rd_free, rgd->rd_free_clone, rgd->rd_dinodes);
  	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
  ",

  		(unsigned long long)rgd->rd_addr);

  	fs_warn(sdp, "umount on all nodes and run fsck.gfs2 to fix the error
  ");
  	gfs2_rgrp_dump(NULL, rgd->rd_gl);
  	rgd->rd_flags |= GFS2_RDF_ERROR;
  }

  /**

   * gfs2_alloc_blocks - Allocate one or more blocks of data and/or a dinode

   * @ip: the inode to allocate the block for

   * @bn: Used to return the starting block number

   * @ndata: requested number of blocks/extent length (value/result)

   * @dinode: 1 if we're allocating a dinode block, else 0

   * @generation: the generation number of the inode

   *

   * Returns: 0 or error

   */

  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_rgrpd *rgd;

  	unsigned int ndata;
  	u32 goal, blk; /* block, within the rgrp scope */

  	u64 block; /* block, within the file system scope */

  	int error;

  	struct gfs2_bitmap *bi;

  	/* Only happens if there is a bug in gfs2, return something distinctive
  	 * to ensure that it is noticed.
  	 */

  	if (ip->i_res == NULL)

  		return -ECANCELED;

  	rgd = ip->i_rgd;

  	if (!dinode && rgrp_contains_block(rgd, ip->i_goal))

  		goal = ip->i_goal - rgd->rd_data0;

  	else

  		goal = rgd->rd_last_alloc;

  	blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, &bi);

  
  	/* Since all blocks are reserved in advance, this shouldn't happen */
  	if (blk == BFITNOENT)
  		goto rgrp_error;

  	block = gfs2_alloc_extent(rgd, bi, blk, dinode, 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 (rgd->rd_free < *nblocks)

  		goto rgrp_error;

  	rgd->rd_free -= *nblocks;

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

  	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_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);

  	rgd->rd_free_clone -= *nblocks;
  	trace_gfs2_block_alloc(ip, block, *nblocks,

  			       dinode ? GFS2_BLKST_DINODE : GFS2_BLKST_USED);

  	*bn = block;
  	return 0;
  
  rgrp_error:
  	gfs2_rgrp_error(rgd);
  	return -EIO;

  }
  
  /**

   * __gfs2_free_blocks - free a contiguous run of 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

   * @meta: 1 if the blocks represent metadata

   *
   */

  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, bstart, blen, GFS2_BLKST_FREE);

  	rgd->rd_free += blen;

  	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);

  	/* Directories keep their data in the metadata address space */

  	if (meta || ip->i_depth)

  		gfs2_meta_wipe(ip, bstart, blen);

  }

  /**

   * 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);

  	__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, 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);

  }

  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_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, 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);

  }
  
  /**

   * gfs2_check_blk_type - Check the type of a block
   * @sdp: The superblock
   * @no_addr: The block number to check
   * @type: The block type we are looking for
   *
   * Returns: 0 if the block type matches the expected type
   *          -ESTALE if it doesn't match
   *          or -ve errno if something went wrong while checking
   */
  
  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;

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

  
  	error = -EINVAL;
  	rgd = gfs2_blk2rgrpd(sdp, no_addr);
  	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;
  }
  
  /**

   * gfs2_rlist_add - add a RG to a list of RGs

   * @ip: the inode

   * @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_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);

  	if (!rgd) {

  		fs_err(sdp, "rlist_add: no rgrp for block %llu
  ", (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;
  }
  
  /**
   * 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)

  {
  	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]);
  }
  
  /**
   * 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);
  	}
  }