[GFS2] The core of GFS2

This patch contains all the core files for GFS2.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 1206 insertions, 0 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
new file mode 100644
index 000000000000..4b4e295b3bf5
--- /dev/null
+++ b/fs/gfs2/bmap.c
@@ -0,0 +1,1206 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <asm/semaphore.h>
+
+#include "gfs2.h"
+#include "bmap.h"
+#include "glock.h"
+#include "inode.h"
+#include "jdata.h"
+#include "meta_io.h"
+#include "page.h"
+#include "quota.h"
+#include "rgrp.h"
+#include "trans.h"
+
+/* This doesn't need to be that large as max 64 bit pointers in a 4k
+ * block is 512, so __u16 is fine for that. It saves stack space to
+ * keep it small.
+ */
+struct metapath {
+	__u16 mp_list[GFS2_MAX_META_HEIGHT];
+};
+
+typedef int (*block_call_t) (struct gfs2_inode *ip, struct buffer_head *dibh,
+			     struct buffer_head *bh, uint64_t *top,
+			     uint64_t *bottom, unsigned int height,
+			     void *data);
+
+struct strip_mine {
+	int sm_first;
+	unsigned int sm_height;
+};
+
+/**
+ * @gfs2_unstuffer_sync - Synchronously unstuff a dinode
+ * @ip:
+ * @dibh:
+ * @block:
+ * @private:
+ *
+ * Cheat and use a metadata buffer instead of a data page.
+ *
+ * Returns: errno
+ */
+
+int gfs2_unstuffer_sync(struct gfs2_inode *ip, struct buffer_head *dibh,
+			uint64_t block, void *private)
+{
+	struct buffer_head *bh;
+	int error;
+
+	bh = gfs2_meta_new(ip->i_gl, block);
+
+	gfs2_buffer_copy_tail(bh, 0, dibh, sizeof(struct gfs2_dinode));
+
+	set_buffer_dirty(bh);
+	error = sync_dirty_buffer(bh);
+
+	brelse(bh);
+
+	return error;
+}
+
+/**
+ * gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big
+ * @ip: The GFS2 inode to unstuff
+ * @unstuffer: the routine that handles unstuffing a non-zero length file
+ * @private: private data for the unstuffer
+ *
+ * This routine unstuffs a dinode and returns it to a "normal" state such
+ * that the height can be grown in the traditional way.
+ *
+ * Returns: errno
+ */
+
+int gfs2_unstuff_dinode(struct gfs2_inode *ip, gfs2_unstuffer_t unstuffer,
+			void *private)
+{
+	struct buffer_head *bh, *dibh;
+	uint64_t block = 0;
+	int journaled = gfs2_is_jdata(ip);
+	int error;
+
+	down_write(&ip->i_rw_mutex);
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		goto out;
+		
+	if (ip->i_di.di_size) {
+		/* Get a free block, fill it with the stuffed data,
+		   and write it out to disk */
+
+		if (journaled) {
+			block = gfs2_alloc_meta(ip);
+
+			error = gfs2_jdata_get_buffer(ip, block, 1, &bh);
+			if (error)
+				goto out_brelse;
+			gfs2_buffer_copy_tail(bh,
+					      sizeof(struct gfs2_meta_header),
+					      dibh, sizeof(struct gfs2_dinode));
+			brelse(bh);
+		} else {
+			block = gfs2_alloc_data(ip);
+
+			error = unstuffer(ip, dibh, block, private);
+			if (error)
+				goto out_brelse;
+		}
+	}
+
+	/*  Set up the pointer to the new block  */
+
+	gfs2_trans_add_bh(ip->i_gl, dibh);
+
+	gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
+
+	if (ip->i_di.di_size) {
+		*(uint64_t *)(dibh->b_data + sizeof(struct gfs2_dinode)) = cpu_to_be64(block);
+		ip->i_di.di_blocks++;
+	}
+
+	ip->i_di.di_height = 1;
+
+	gfs2_dinode_out(&ip->i_di, dibh->b_data);
+
+ out_brelse:
+	brelse(dibh);
+
+ out:
+	up_write(&ip->i_rw_mutex);
+
+	return error;
+}
+
+/**
+ * calc_tree_height - Calculate the height of a metadata tree
+ * @ip: The GFS2 inode
+ * @size: The proposed size of the file
+ *
+ * Work out how tall a metadata tree needs to be in order to accommodate a
+ * file of a particular size. If size is less than the current size of
+ * the inode, then the current size of the inode is used instead of the
+ * supplied one.
+ *
+ * Returns: the height the tree should be
+ */
+
+static unsigned int calc_tree_height(struct gfs2_inode *ip, uint64_t size)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	uint64_t *arr;
+	unsigned int max, height;
+
+	if (ip->i_di.di_size > size)
+		size = ip->i_di.di_size;
+
+	if (gfs2_is_jdata(ip)) {
+		arr = sdp->sd_jheightsize;
+		max = sdp->sd_max_jheight;
+	} else {
+		arr = sdp->sd_heightsize;
+		max = sdp->sd_max_height;
+	}
+
+	for (height = 0; height < max; height++)
+		if (arr[height] >= size)
+			break;
+
+	return height;
+}
+
+/**
+ * build_height - Build a metadata tree of the requested height
+ * @ip: The GFS2 inode
+ * @height: The height to build to
+ *
+ * This routine makes sure that the metadata tree is tall enough to hold
+ * "size" bytes of data.
+ *
+ * Returns: errno
+ */
+
+static int build_height(struct gfs2_inode *ip, int height)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct buffer_head *bh, *dibh;
+	uint64_t block = 0, *bp;
+	unsigned int x;
+	int new_block;
+	int error;
+
+	while (ip->i_di.di_height < height) {
+		error = gfs2_meta_inode_buffer(ip, &dibh);
+		if (error)
+			return error;
+
+		new_block = 0;
+		bp = (uint64_t *)(dibh->b_data + sizeof(struct gfs2_dinode));
+		for (x = 0; x < sdp->sd_diptrs; x++, bp++)
+			if (*bp) {
+				new_block = 1;
+				break;
+			}
+
+		if (new_block) {
+			/* Get a new block, fill it with the old direct
+			   pointers, and write it out */
+
+			block = gfs2_alloc_meta(ip);
+
+			bh = gfs2_meta_new(ip->i_gl, block);
+			gfs2_trans_add_bh(ip->i_gl, bh);
+			gfs2_metatype_set(bh,
+					  GFS2_METATYPE_IN,
+					  GFS2_FORMAT_IN);
+			gfs2_buffer_copy_tail(bh,
+					      sizeof(struct gfs2_meta_header),
+					      dibh, sizeof(struct gfs2_dinode));
+
+			brelse(bh);
+		}
+
+		/*  Set up the new direct pointer and write it out to disk  */
+
+		gfs2_trans_add_bh(ip->i_gl, dibh);
+
+		gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
+
+		if (new_block) {
+			*(uint64_t *)(dibh->b_data + sizeof(struct gfs2_dinode)) = cpu_to_be64(block);
+			ip->i_di.di_blocks++;
+		}
+
+		ip->i_di.di_height++;
+
+		gfs2_dinode_out(&ip->i_di, dibh->b_data);
+		brelse(dibh);
+	}
+
+	return 0;
+}
+
+/**
+ * find_metapath - Find path through the metadata tree
+ * @ip: The inode pointer
+ * @mp: The metapath to return the result in
+ * @block: The disk block to look up
+ *
+ *   This routine returns a struct metapath structure that defines a path
+ *   through the metadata of inode "ip" to get to block "block".
+ *
+ *   Example:
+ *   Given:  "ip" is a height 3 file, "offset" is 101342453, and this is a
+ *   filesystem with a blocksize of 4096.
+ *
+ *   find_metapath() would return a struct metapath structure set to:
+ *   mp_offset = 101342453, mp_height = 3, mp_list[0] = 0, mp_list[1] = 48,
+ *   and mp_list[2] = 165.
+ *
+ *   That means that in order to get to the block containing the byte at
+ *   offset 101342453, we would load the indirect block pointed to by pointer
+ *   0 in the dinode.  We would then load the indirect block pointed to by
+ *   pointer 48 in that indirect block.  We would then load the data block
+ *   pointed to by pointer 165 in that indirect block.
+ *
+ *             ----------------------------------------
+ *             | Dinode |                             |
+ *             |        |                            4|
+ *             |        |0 1 2 3 4 5                 9|
+ *             |        |                            6|
+ *             ----------------------------------------
+ *                       |
+ *                       |
+ *                       V
+ *             ----------------------------------------
+ *             | Indirect Block                       |
+ *             |                                     5|
+ *             |            4 4 4 4 4 5 5            1|
+ *             |0           5 6 7 8 9 0 1            2|
+ *             ----------------------------------------
+ *                                |
+ *                                |
+ *                                V
+ *             ----------------------------------------
+ *             | Indirect Block                       |
+ *             |                         1 1 1 1 1   5|
+ *             |                         6 6 6 6 6   1|
+ *             |0                        3 4 5 6 7   2|
+ *             ----------------------------------------
+ *                                           |
+ *                                           |
+ *                                           V
+ *             ----------------------------------------
+ *             | Data block containing offset         |
+ *             |            101342453                 |
+ *             |                                      |
+ *             |                                      |
+ *             ----------------------------------------
+ *
+ */
+
+static void find_metapath(struct gfs2_inode *ip, uint64_t block, struct metapath *mp)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	uint64_t b = block;
+	unsigned int i;
+
+	for (i = ip->i_di.di_height; i--;)
+		mp->mp_list[i] = (__u16)do_div(b, sdp->sd_inptrs);
+
+}
+
+/**
+ * metapointer - Return pointer to start of metadata in a buffer
+ * @bh: The buffer
+ * @height: The metadata height (0 = dinode)
+ * @mp: The metapath
+ *
+ * Return a pointer to the block number of the next height of the metadata
+ * tree given a buffer containing the pointer to the current height of the
+ * metadata tree.
+ */
+
+static inline uint64_t *metapointer(struct buffer_head *bh,
+				    unsigned int height, struct metapath *mp)
+{
+	unsigned int head_size = (height > 0) ?
+		sizeof(struct gfs2_meta_header) : sizeof(struct gfs2_dinode);
+
+	return ((uint64_t *)(bh->b_data + head_size)) + mp->mp_list[height];
+}
+
+/**
+ * lookup_block - Get the next metadata block in metadata tree
+ * @ip: The GFS2 inode
+ * @bh: Buffer containing the pointers to metadata blocks
+ * @height: The height of the tree (0 = dinode)
+ * @mp: The metapath
+ * @create: Non-zero if we may create a new meatdata block
+ * @new: Used to indicate if we did create a new metadata block
+ * @block: the returned disk block number
+ *
+ * Given a metatree, complete to a particular height, checks to see if the next
+ * height of the tree exists. If not the next height of the tree is created.
+ * The block number of the next height of the metadata tree is returned.
+ *
+ */
+
+static void lookup_block(struct gfs2_inode *ip, struct buffer_head *bh,
+			 unsigned int height, struct metapath *mp, int create,
+			 int *new, uint64_t *block)
+{
+	uint64_t *ptr = metapointer(bh, height, mp);
+
+	if (*ptr) {
+		*block = be64_to_cpu(*ptr);
+		return;
+	}
+
+	*block = 0;
+
+	if (!create)
+		return;
+
+	if (height == ip->i_di.di_height - 1 &&
+	    !gfs2_is_jdata(ip))
+		*block = gfs2_alloc_data(ip);
+	else
+		*block = gfs2_alloc_meta(ip);
+
+	gfs2_trans_add_bh(ip->i_gl, bh);
+
+	*ptr = cpu_to_be64(*block);
+	ip->i_di.di_blocks++;
+
+	*new = 1;
+}
+
+/**
+ * gfs2_block_map - Map a block from an inode to a disk block
+ * @ip: The GFS2 inode
+ * @lblock: The logical block number
+ * @new: Value/Result argument (1 = may create/did create new blocks)
+ * @dblock: the disk block number of the start of an extent
+ * @extlen: the size of the extent
+ *
+ * Find the block number on the current device which corresponds to an
+ * inode's block. If the block had to be created, "new" will be set.
+ *
+ * Returns: errno
+ */
+
+int gfs2_block_map(struct gfs2_inode *ip, uint64_t lblock, int *new,
+		   uint64_t *dblock, uint32_t *extlen)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct buffer_head *bh;
+	struct metapath mp;
+	int create = *new;
+	unsigned int bsize;
+	unsigned int height;
+	unsigned int end_of_metadata;
+	unsigned int x;
+	int error = 0;
+
+	*new = 0;
+	*dblock = 0;
+	if (extlen)
+		*extlen = 0;
+
+	if (create)
+		down_write(&ip->i_rw_mutex);
+	else
+		down_read(&ip->i_rw_mutex);
+
+	if (gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
+		goto out;
+
+	bsize = (gfs2_is_jdata(ip)) ? sdp->sd_jbsize : sdp->sd_sb.sb_bsize;
+
+	height = calc_tree_height(ip, (lblock + 1) * bsize);
+	if (ip->i_di.di_height < height) {
+		if (!create)
+			goto out;
+
+		error = build_height(ip, height);
+		if (error)
+			goto out;
+	}
+
+	find_metapath(ip, lblock, &mp);
+	end_of_metadata = ip->i_di.di_height - 1;
+
+	error = gfs2_meta_inode_buffer(ip, &bh);
+	if (error)
+		goto out;
+
+	for (x = 0; x < end_of_metadata; x++) {
+		lookup_block(ip, bh, x, &mp, create, new, dblock);
+		brelse(bh);
+		if (!*dblock)
+			goto out;
+
+		error = gfs2_meta_indirect_buffer(ip, x+1, *dblock, *new, &bh);
+		if (error)
+			goto out;
+	}
+
+	lookup_block(ip, bh, end_of_metadata, &mp, create, new, dblock);
+
+	if (extlen && *dblock) {
+		*extlen = 1;
+
+		if (!*new) {
+			uint64_t tmp_dblock;
+			int tmp_new;
+			unsigned int nptrs;
+
+			nptrs = (end_of_metadata) ? sdp->sd_inptrs :
+						    sdp->sd_diptrs;
+
+			while (++mp.mp_list[end_of_metadata] < nptrs) {
+				lookup_block(ip, bh, end_of_metadata, &mp,
+					     0, &tmp_new, &tmp_dblock);
+
+				if (*dblock + *extlen != tmp_dblock)
+					break;
+
+				(*extlen)++;
+			}
+		}
+	}
+
+	brelse(bh);
+
+	if (*new) {
+		error = gfs2_meta_inode_buffer(ip, &bh);
+		if (!error) {
+			gfs2_trans_add_bh(ip->i_gl, bh);
+			gfs2_dinode_out(&ip->i_di, bh->b_data);
+			brelse(bh);
+		}
+	}
+
+ out:
+	if (create)
+		up_write(&ip->i_rw_mutex);
+	else
+		up_read(&ip->i_rw_mutex);
+
+	return error;
+}
+
+/**
+ * recursive_scan - recursively scan through the end of a file
+ * @ip: the inode
+ * @dibh: the dinode buffer
+ * @mp: the path through the metadata to the point to start
+ * @height: the height the recursion is at
+ * @block: the indirect block to look at
+ * @first: 1 if this is the first block
+ * @bc: the call to make for each piece of metadata
+ * @data: data opaque to this function to pass to @bc
+ *
+ * When this is first called @height and @block should be zero and
+ * @first should be 1.
+ *
+ * Returns: errno
+ */
+
+static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
+			  struct metapath *mp, unsigned int height,
+			  uint64_t block, int first, block_call_t bc,
+			  void *data)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct buffer_head *bh = NULL;
+	uint64_t *top, *bottom;
+	uint64_t bn;
+	int error;
+	int mh_size = sizeof(struct gfs2_meta_header);
+
+	if (!height) {
+		error = gfs2_meta_inode_buffer(ip, &bh);
+		if (error)
+			return error;
+		dibh = bh;
+
+		top = (uint64_t *)(bh->b_data + sizeof(struct gfs2_dinode)) +
+			mp->mp_list[0];
+		bottom = (uint64_t *)(bh->b_data + sizeof(struct gfs2_dinode)) +
+			sdp->sd_diptrs;
+	} else {
+		error = gfs2_meta_indirect_buffer(ip, height, block, 0, &bh);
+		if (error)
+			return error;
+
+		top = (uint64_t *)(bh->b_data + mh_size) +
+				  ((first) ? mp->mp_list[height] : 0);
+
+		bottom = (uint64_t *)(bh->b_data + mh_size) + sdp->sd_inptrs;
+	}
+
+	error = bc(ip, dibh, bh, top, bottom, height, data);
+	if (error)
+		goto out;
+
+	if (height < ip->i_di.di_height - 1)
+		for (; top < bottom; top++, first = 0) {
+			if (!*top)
+				continue;
+
+			bn = be64_to_cpu(*top);
+
+			error = recursive_scan(ip, dibh, mp, height + 1, bn,
+					       first, bc, data);
+			if (error)
+				break;
+		}
+
+ out:
+	brelse(bh);
+
+	return error;
+}
+
+/**
+ * do_strip - Look for a layer a particular layer of the file and strip it off
+ * @ip: the inode
+ * @dibh: the dinode buffer
+ * @bh: A buffer of pointers
+ * @top: The first pointer in the buffer
+ * @bottom: One more than the last pointer
+ * @height: the height this buffer is at
+ * @data: a pointer to a struct strip_mine
+ *
+ * Returns: errno
+ */
+
+static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh,
+		    struct buffer_head *bh, uint64_t *top, uint64_t *bottom,
+		    unsigned int height, void *data)
+{
+	struct strip_mine *sm = (struct strip_mine *)data;
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct gfs2_rgrp_list rlist;
+	uint64_t bn, bstart;
+	uint32_t blen;
+	uint64_t *p;
+	unsigned int rg_blocks = 0;
+	int metadata;
+	unsigned int revokes = 0;
+	int x;
+	int error;
+
+	if (!*top)
+		sm->sm_first = 0;
+
+	if (height != sm->sm_height)
+		return 0;
+
+	if (sm->sm_first) {
+		top++;
+		sm->sm_first = 0;
+	}
+
+	metadata = (height != ip->i_di.di_height - 1) || gfs2_is_jdata(ip);
+	if (metadata)
+		revokes = (height) ? sdp->sd_inptrs : sdp->sd_diptrs;
+
+	error = gfs2_rindex_hold(sdp, &ip->i_alloc.al_ri_gh);
+	if (error)
+		return error;
+
+	memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
+	bstart = 0;
+	blen = 0;
+
+	for (p = top; p < bottom; p++) {
+		if (!*p)
+			continue;
+
+		bn = be64_to_cpu(*p);
+
+		if (bstart + blen == bn)
+			blen++;
+		else {
+			if (bstart)
+				gfs2_rlist_add(sdp, &rlist, bstart);
+
+			bstart = bn;
+			blen = 1;
+		}
+	}
+
+	if (bstart)
+		gfs2_rlist_add(sdp, &rlist, bstart);
+	else
+		goto out; /* Nothing to do */
+
+	gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE, 0);
+
+	for (x = 0; x < rlist.rl_rgrps; x++) {
+		struct gfs2_rgrpd *rgd;
+		rgd = get_gl2rgd(rlist.rl_ghs[x].gh_gl);
+		rg_blocks += rgd->rd_ri.ri_length;
+	}
+
+	error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
+	if (error)
+		goto out_rlist;
+
+	error = gfs2_trans_begin(sdp, rg_blocks + RES_DINODE +
+				 RES_INDIRECT + RES_STATFS + RES_QUOTA,
+				 revokes);
+	if (error)
+		goto out_rg_gunlock;
+
+	down_write(&ip->i_rw_mutex);
+
+	gfs2_trans_add_bh(ip->i_gl, dibh);
+	gfs2_trans_add_bh(ip->i_gl, bh);
+
+	bstart = 0;
+	blen = 0;
+
+	for (p = top; p < bottom; p++) {
+		if (!*p)
+			continue;
+
+		bn = be64_to_cpu(*p);
+
+		if (bstart + blen == bn)
+			blen++;
+		else {
+			if (bstart) {
+				if (metadata)
+					gfs2_free_meta(ip, bstart, blen);
+				else
+					gfs2_free_data(ip, bstart, blen);
+			}
+
+			bstart = bn;
+			blen = 1;
+		}
+
+		*p = 0;
+		if (!ip->i_di.di_blocks)
+			gfs2_consist_inode(ip);
+		ip->i_di.di_blocks--;
+	}
+	if (bstart) {
+		if (metadata)
+			gfs2_free_meta(ip, bstart, blen);
+		else
+			gfs2_free_data(ip, bstart, blen);
+	}
+
+	ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
+
+	gfs2_dinode_out(&ip->i_di, dibh->b_data);
+
+	up_write(&ip->i_rw_mutex);
+
+	gfs2_trans_end(sdp);
+
+ out_rg_gunlock:
+	gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
+
+ out_rlist:
+	gfs2_rlist_free(&rlist);
+
+ out:
+	gfs2_glock_dq_uninit(&ip->i_alloc.al_ri_gh);
+
+	return error;
+}
+
+/**
+ * do_grow - Make a file look bigger than it is
+ * @ip: the inode
+ * @size: the size to set the file to
+ *
+ * Called with an exclusive lock on @ip.
+ *
+ * Returns: errno
+ */
+
+static int do_grow(struct gfs2_inode *ip, uint64_t size)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct gfs2_alloc *al;
+	struct buffer_head *dibh;
+	unsigned int h;
+	int error;
+
+	al = gfs2_alloc_get(ip);
+
+	error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
+	if (error)
+		goto out;
+
+	error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
+	if (error)
+		goto out_gunlock_q;
+
+	al->al_requested = sdp->sd_max_height + RES_DATA;
+
+	error = gfs2_inplace_reserve(ip);
+	if (error)
+		goto out_gunlock_q;
+
+	error = gfs2_trans_begin(sdp,
+			sdp->sd_max_height + al->al_rgd->rd_ri.ri_length +
+			RES_JDATA + RES_DINODE + RES_STATFS + RES_QUOTA, 0);
+	if (error)
+		goto out_ipres;
+
+	if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
+		if (gfs2_is_stuffed(ip)) {
+			error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
+						    NULL);
+			if (error)
+				goto out_end_trans;
+		}
+
+		h = calc_tree_height(ip, size);
+		if (ip->i_di.di_height < h) {
+			down_write(&ip->i_rw_mutex);
+			error = build_height(ip, h);
+			up_write(&ip->i_rw_mutex);
+			if (error)
+				goto out_end_trans;
+		}
+	}
+
+	ip->i_di.di_size = size;
+	ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		goto out_end_trans;
+
+	gfs2_trans_add_bh(ip->i_gl, dibh);
+	gfs2_dinode_out(&ip->i_di, dibh->b_data);
+	brelse(dibh);
+
+ out_end_trans:
+	gfs2_trans_end(sdp);
+
+ out_ipres:
+	gfs2_inplace_release(ip);
+
+ out_gunlock_q:
+	gfs2_quota_unlock(ip);
+
+ out:
+	gfs2_alloc_put(ip);
+
+	return error;
+}
+
+static int truncator_journaled(struct gfs2_inode *ip, uint64_t size)
+{
+	uint64_t lbn, dbn;
+	uint32_t off;
+	struct buffer_head *bh;
+	int new = 0;
+	int error;
+
+	lbn = size;
+	off = do_div(lbn, ip->i_sbd->sd_jbsize);
+
+	error = gfs2_block_map(ip, lbn, &new, &dbn, NULL);
+	if (error || !dbn)
+		return error;
+
+	error = gfs2_jdata_get_buffer(ip, dbn, 0, &bh);
+	if (error)
+		return error;
+
+	gfs2_trans_add_bh(ip->i_gl, bh);
+	gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header) + off);
+
+	brelse(bh);
+
+	return 0;
+}
+
+static int trunc_start(struct gfs2_inode *ip, uint64_t size,
+		       gfs2_truncator_t truncator)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct buffer_head *dibh;
+	int journaled = gfs2_is_jdata(ip);
+	int error;
+
+	error = gfs2_trans_begin(sdp,
+				 RES_DINODE + ((journaled) ? RES_JDATA : 0), 0);
+	if (error)
+		return error;
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		goto out;
+
+	if (gfs2_is_stuffed(ip)) {
+		ip->i_di.di_size = size;
+		ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
+		gfs2_trans_add_bh(ip->i_gl, dibh);
+		gfs2_dinode_out(&ip->i_di, dibh->b_data);
+		gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + size);
+		error = 1;
+
+	} else {
+		if (journaled) {
+			uint64_t junk = size;
+			/* we're just interested in the modulus */
+			if (do_div(junk, sdp->sd_jbsize))
+				error = truncator_journaled(ip, size);
+		} else if (size & (uint64_t)(sdp->sd_sb.sb_bsize - 1))
+			error = truncator(ip, size);
+
+		if (!error) {
+			ip->i_di.di_size = size;
+			ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
+			ip->i_di.di_flags |= GFS2_DIF_TRUNC_IN_PROG;
+			gfs2_trans_add_bh(ip->i_gl, dibh);
+			gfs2_dinode_out(&ip->i_di, dibh->b_data);
+		}
+	}
+
+	brelse(dibh);
+
+ out:
+	gfs2_trans_end(sdp);
+
+	return error;
+}
+
+static int trunc_dealloc(struct gfs2_inode *ip, uint64_t size)
+{
+	unsigned int height = ip->i_di.di_height;
+	uint64_t lblock;
+	struct metapath mp;
+	int error;
+
+	if (!size)
+		lblock = 0;
+	else if (gfs2_is_jdata(ip)) {
+		lblock = size - 1;
+		do_div(lblock, ip->i_sbd->sd_jbsize);
+	} else
+		lblock = (size - 1) >> ip->i_sbd->sd_sb.sb_bsize_shift;
+
+	find_metapath(ip, lblock, &mp);
+	gfs2_alloc_get(ip);
+
+	error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
+	if (error)
+		goto out;
+
+	while (height--) {
+		struct strip_mine sm;
+		sm.sm_first = !!size;
+		sm.sm_height = height;
+
+		error = recursive_scan(ip, NULL, &mp, 0, 0, 1, do_strip, &sm);
+		if (error)
+			break;
+	}
+
+	gfs2_quota_unhold(ip);
+
+ out:
+	gfs2_alloc_put(ip);
+	return error;
+}
+
+static int trunc_end(struct gfs2_inode *ip)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct buffer_head *dibh;
+	int error;
+
+	error = gfs2_trans_begin(sdp, RES_DINODE, 0);
+	if (error)
+		return error;
+
+	down_write(&ip->i_rw_mutex);
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		goto out;
+
+	if (!ip->i_di.di_size) {
+		ip->i_di.di_height = 0;
+		ip->i_di.di_goal_meta =
+			ip->i_di.di_goal_data =
+			ip->i_num.no_addr;
+		gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
+	}
+	ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
+	ip->i_di.di_flags &= ~GFS2_DIF_TRUNC_IN_PROG;
+
+	gfs2_trans_add_bh(ip->i_gl, dibh);
+	gfs2_dinode_out(&ip->i_di, dibh->b_data);
+	brelse(dibh);
+
+ out:
+	up_write(&ip->i_rw_mutex);
+
+	gfs2_trans_end(sdp);
+
+	return error;
+}
+
+/**
+ * do_shrink - make a file smaller
+ * @ip: the inode
+ * @size: the size to make the file
+ * @truncator: function to truncate the last partial block
+ *
+ * Called with an exclusive lock on @ip.
+ *
+ * Returns: errno
+ */
+
+static int do_shrink(struct gfs2_inode *ip, uint64_t size,
+		     gfs2_truncator_t truncator)
+{
+	int error;
+
+	error = trunc_start(ip, size, truncator);
+	if (error < 0)
+		return error;
+	if (error > 0)
+		return 0;
+
+	error = trunc_dealloc(ip, size);
+	if (!error)
+		error = trunc_end(ip);
+
+	return error;
+}
+
+/**
+ * gfs2_truncatei - make a file a give size
+ * @ip: the inode
+ * @size: the size to make the file
+ * @truncator: function to truncate the last partial block
+ *
+ * The file size can grow, shrink, or stay the same size.
+ *
+ * Returns: errno
+ */
+
+int gfs2_truncatei(struct gfs2_inode *ip, uint64_t size,
+		   gfs2_truncator_t truncator)
+{
+	int error;
+
+	if (gfs2_assert_warn(ip->i_sbd, S_ISREG(ip->i_di.di_mode)))
+		return -EINVAL;
+
+	if (size > ip->i_di.di_size)
+		error = do_grow(ip, size);
+	else
+		error = do_shrink(ip, size, truncator);
+
+	return error;
+}
+
+int gfs2_truncatei_resume(struct gfs2_inode *ip)
+{
+	int error;
+	error = trunc_dealloc(ip, ip->i_di.di_size);
+	if (!error)
+		error = trunc_end(ip);
+	return error;
+}
+
+int gfs2_file_dealloc(struct gfs2_inode *ip)
+{
+	return trunc_dealloc(ip, 0);
+}
+
+/**
+ * gfs2_write_calc_reserv - calculate number of blocks needed to write to a file
+ * @ip: the file
+ * @len: the number of bytes to be written to the file
+ * @data_blocks: returns the number of data blocks required
+ * @ind_blocks: returns the number of indirect blocks required
+ *
+ */
+
+void gfs2_write_calc_reserv(struct gfs2_inode *ip, unsigned int len,
+			    unsigned int *data_blocks, unsigned int *ind_blocks)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	unsigned int tmp;
+
+	if (gfs2_is_jdata(ip)) {
+		*data_blocks = DIV_RU(len, sdp->sd_jbsize) + 2;
+		*ind_blocks = 3 * (sdp->sd_max_jheight - 1);
+	} else {
+		*data_blocks = (len >> sdp->sd_sb.sb_bsize_shift) + 3;
+		*ind_blocks = 3 * (sdp->sd_max_height - 1);
+	}
+
+	for (tmp = *data_blocks; tmp > sdp->sd_diptrs;) {
+		tmp = DIV_RU(tmp, sdp->sd_inptrs);
+		*ind_blocks += tmp;
+	}
+}
+
+/**
+ * gfs2_write_alloc_required - figure out if a write will require an allocation
+ * @ip: the file being written to
+ * @offset: the offset to write to
+ * @len: the number of bytes being written
+ * @alloc_required: set to 1 if an alloc is required, 0 otherwise
+ *
+ * Returns: errno
+ */
+
+int gfs2_write_alloc_required(struct gfs2_inode *ip, uint64_t offset,
+			      unsigned int len, int *alloc_required)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	uint64_t lblock, lblock_stop, dblock;
+	uint32_t extlen;
+	int new = 0;
+	int error = 0;
+
+	*alloc_required = 0;
+
+	if (!len)
+		return 0;
+
+	if (gfs2_is_stuffed(ip)) {
+		if (offset + len >
+		    sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))
+			*alloc_required = 1;
+		return 0;
+	}
+
+	if (gfs2_is_jdata(ip)) {
+		unsigned int bsize = sdp->sd_jbsize;
+		lblock = offset;
+		do_div(lblock, bsize);
+		lblock_stop = offset + len + bsize - 1;
+		do_div(lblock_stop, bsize);
+	} else {
+		unsigned int shift = sdp->sd_sb.sb_bsize_shift;
+		lblock = offset >> shift;
+		lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
+	}
+
+	for (; lblock < lblock_stop; lblock += extlen) {
+		error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
+		if (error)
+			return error;
+
+		if (!dblock) {
+			*alloc_required = 1;
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * do_gfm - Copy out the dinode/indirect blocks of a file
+ * @ip: the file
+ * @dibh: the dinode buffer
+ * @bh: the indirect buffer we're looking at
+ * @top: the first pointer in the block
+ * @bottom: one more than the last pointer in the block
+ * @height: the height the block is at
+ * @data: a pointer to a struct gfs2_user_buffer structure
+ *
+ * If this is a journaled file, copy out the data too.
+ *
+ * Returns: errno
+ */
+
+static int do_gfm(struct gfs2_inode *ip, struct buffer_head *dibh,
+		  struct buffer_head *bh, uint64_t *top, uint64_t *bottom,
+		  unsigned int height, void *data)
+{
+	struct gfs2_user_buffer *ub = (struct gfs2_user_buffer *)data;
+	int error;
+
+	error = gfs2_add_bh_to_ub(ub, bh);
+	if (error)
+		return error;
+
+	if (!S_ISDIR(ip->i_di.di_mode) ||
+	    height + 1 != ip->i_di.di_height)
+		return 0;
+
+	for (; top < bottom; top++)
+		if (*top) {
+			struct buffer_head *data_bh;
+
+			error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*top),
+					       DIO_START | DIO_WAIT,
+					       &data_bh);
+			if (error)
+				return error;
+
+			error = gfs2_add_bh_to_ub(ub, data_bh);
+
+			brelse(data_bh);
+
+			if (error)
+				return error;
+		}
+
+	return 0;
+}
+
+/**
+ * gfs2_get_file_meta - return all the metadata for a file
+ * @ip: the file
+ * @ub: the structure representing the meta
+ *
+ * Returns: errno
+ */
+
+int gfs2_get_file_meta(struct gfs2_inode *ip, struct gfs2_user_buffer *ub)
+{
+	int error;
+
+	if (gfs2_is_stuffed(ip)) {
+		struct buffer_head *dibh;
+		error = gfs2_meta_inode_buffer(ip, &dibh);
+		if (!error) {
+			error = gfs2_add_bh_to_ub(ub, dibh);
+			brelse(dibh);
+		}
+	} else {
+		struct metapath mp;
+		find_metapath(ip, 0, &mp);
+		error = recursive_scan(ip, NULL, &mp, 0, 0, 1, do_gfm, ub);
+	}
+
+	return error;
+}
+