1 files changed, 1221 insertions, 0 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
new file mode 100644
index 000000000000..cc57f2ecd219
--- /dev/null
+++ b/fs/gfs2/bmap.c
@@ -0,0 +1,1221 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 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/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/gfs2_ondisk.h>
+#include <linux/crc32.h>
+#include <linux/lm_interface.h>
+
+#include "gfs2.h"
+#include "incore.h"
+#include "bmap.h"
+#include "glock.h"
+#include "inode.h"
+#include "meta_io.h"
+#include "quota.h"
+#include "rgrp.h"
+#include "trans.h"
+#include "dir.h"
+#include "util.h"
+#include "ops_address.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, u64 *top,
+                             u64 *bottom, unsigned int height,
+                             void *data);
+
+struct strip_mine {
+        int sm_first;
+        unsigned int sm_height;
+};
+
+/**
+ * gfs2_unstuffer_page - unstuff a stuffed inode into a block cached by a page
+ * @ip: the inode
+ * @dibh: the dinode buffer
+ * @block: the block number that was allocated
+ * @private: any locked page held by the caller process
+ *
+ * Returns: errno
+ */
+
+static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
+                               u64 block, struct page *page)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        struct inode *inode = &ip->i_inode;
+        struct buffer_head *bh;
+        int release = 0;
+
+        if (!page || page->index) {
+                page = grab_cache_page(inode->i_mapping, 0);
+                if (!page)
+                        return -ENOMEM;
+                release = 1;
+        }
+
+        if (!PageUptodate(page)) {
+                void *kaddr = kmap(page);
+
+                memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
+                       ip->i_di.di_size);
+                memset(kaddr + ip->i_di.di_size, 0,
+                       PAGE_CACHE_SIZE - ip->i_di.di_size);
+                kunmap(page);
+
+                SetPageUptodate(page);
+        }
+
+        if (!page_has_buffers(page))
+                create_empty_buffers(page, 1 << inode->i_blkbits,
+                                     (1 << BH_Uptodate));
+
+        bh = page_buffers(page);
+
+        if (!buffer_mapped(bh))
+                map_bh(bh, inode->i_sb, block);
+
+        set_buffer_uptodate(bh);
+        if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip))
+                gfs2_trans_add_bh(ip->i_gl, bh, 0);
+        mark_buffer_dirty(bh);
+
+        if (release) {
+                unlock_page(page);
+                page_cache_release(page);
+        }
+
+        return 0;
+}
+
+/**
+ * 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, struct page *page)
+{
+        struct buffer_head *bh, *dibh;
+        struct gfs2_dinode *di;
+        u64 block = 0;
+        int isdir = gfs2_is_dir(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 (isdir) {
+                        block = gfs2_alloc_meta(ip);
+
+                        error = gfs2_dir_get_new_buffer(ip, block, &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 = gfs2_unstuffer_page(ip, dibh, block, page);
+                        if (error)
+                                goto out_brelse;
+                }
+        }
+
+        /*  Set up the pointer to the new block  */
+
+        gfs2_trans_add_bh(ip->i_gl, dibh, 1);
+        di = (struct gfs2_dinode *)dibh->b_data;
+        gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
+
+        if (ip->i_di.di_size) {
+                *(__be64 *)(di + 1) = cpu_to_be64(block);
+                ip->i_di.di_blocks++;
+                di->di_blocks = cpu_to_be64(ip->i_di.di_blocks);
+        }
+
+        ip->i_di.di_height = 1;
+        di->di_height = cpu_to_be16(1);
+
+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, u64 size)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        u64 *arr;
+        unsigned int max, height;
+
+        if (ip->i_di.di_size > size)
+                size = ip->i_di.di_size;
+
+        if (gfs2_is_dir(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
+ *
+ *
+ * Returns: errno
+ */
+
+static int build_height(struct inode *inode, unsigned height)
+{
+        struct gfs2_inode *ip = GFS2_I(inode);
+        unsigned new_height = height - ip->i_di.di_height;
+        struct buffer_head *dibh;
+        struct buffer_head *blocks[GFS2_MAX_META_HEIGHT];
+        struct gfs2_dinode *di;
+        int error;
+        u64 *bp;
+        u64 bn;
+        unsigned n;
+
+        if (height <= ip->i_di.di_height)
+                return 0;
+
+        error = gfs2_meta_inode_buffer(ip, &dibh);
+        if (error)
+                return error;
+
+        for(n = 0; n < new_height; n++) {
+                bn = gfs2_alloc_meta(ip);
+                blocks[n] = gfs2_meta_new(ip->i_gl, bn);
+                gfs2_trans_add_bh(ip->i_gl, blocks[n], 1);
+        }
+
+        n = 0;
+        bn = blocks[0]->b_blocknr;
+        if (new_height > 1) {
+                for(; n < new_height-1; n++) {
+                        gfs2_metatype_set(blocks[n], GFS2_METATYPE_IN,
+                                          GFS2_FORMAT_IN);
+                        gfs2_buffer_clear_tail(blocks[n],
+                                               sizeof(struct gfs2_meta_header));
+                        bp = (u64 *)(blocks[n]->b_data +
+                                     sizeof(struct gfs2_meta_header));
+                        *bp = cpu_to_be64(blocks[n+1]->b_blocknr);
+                        brelse(blocks[n]);
+                        blocks[n] = NULL;
+                }
+        }
+        gfs2_metatype_set(blocks[n], GFS2_METATYPE_IN, GFS2_FORMAT_IN);
+        gfs2_buffer_copy_tail(blocks[n], sizeof(struct gfs2_meta_header),
+                              dibh, sizeof(struct gfs2_dinode));
+        brelse(blocks[n]);
+        gfs2_trans_add_bh(ip->i_gl, dibh, 1);
+        di = (struct gfs2_dinode *)dibh->b_data;
+        gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
+        *(__be64 *)(di + 1) = cpu_to_be64(bn);
+        ip->i_di.di_height += new_height;
+        ip->i_di.di_blocks += new_height;
+        di->di_height = cpu_to_be16(ip->i_di.di_height);
+        di->di_blocks = cpu_to_be64(ip->i_di.di_blocks);
+        brelse(dibh);
+        return error;
+}
+
+/**
+ * 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, u64 block,
+                          struct metapath *mp)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        u64 b = block;
+        unsigned int i;
+
+        for (i = ip->i_di.di_height; i--;)
+                mp->mp_list[i] = 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 u64 *metapointer(struct buffer_head *bh, int *boundary,
+                               unsigned int height, const struct metapath *mp)
+{
+        unsigned int head_size = (height > 0) ?
+                sizeof(struct gfs2_meta_header) : sizeof(struct gfs2_dinode);
+        u64 *ptr;
+        *boundary = 0;
+        ptr = ((u64 *)(bh->b_data + head_size)) + mp->mp_list[height];
+        if (ptr + 1 == (u64 *)(bh->b_data + bh->b_size))
+                *boundary = 1;
+        return ptr;
+}
+
+/**
+ * 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 int lookup_block(struct gfs2_inode *ip, struct buffer_head *bh,
+                        unsigned int height, struct metapath *mp, int create,
+                        int *new, u64 *block)
+{
+        int boundary;
+        u64 *ptr = metapointer(bh, &boundary, height, mp);
+
+        if (*ptr) {
+                *block = be64_to_cpu(*ptr);
+                return boundary;
+        }
+
+        *block = 0;
+
+        if (!create)
+                return 0;
+
+        if (height == ip->i_di.di_height - 1 && !gfs2_is_dir(ip))
+                *block = gfs2_alloc_data(ip);
+        else
+                *block = gfs2_alloc_meta(ip);
+
+        gfs2_trans_add_bh(ip->i_gl, bh, 1);
+
+        *ptr = cpu_to_be64(*block);
+        ip->i_di.di_blocks++;
+
+        *new = 1;
+        return 0;
+}
+
+/**
+ * gfs2_block_pointers - Map a block from an inode to a disk block
+ * @inode: The inode
+ * @lblock: The logical block number
+ * @map_bh: The bh to be mapped
+ * @mp: metapath to use
+ *
+ * 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
+ */
+
+static int gfs2_block_pointers(struct inode *inode, u64 lblock, int create,
+                               struct buffer_head *bh_map, struct metapath *mp,
+                               unsigned int maxlen)
+{
+        struct gfs2_inode *ip = GFS2_I(inode);
+        struct gfs2_sbd *sdp = GFS2_SB(inode);
+        struct buffer_head *bh;
+        unsigned int bsize;
+        unsigned int height;
+        unsigned int end_of_metadata;
+        unsigned int x;
+        int error = 0;
+        int new = 0;
+        u64 dblock = 0;
+        int boundary;
+
+        BUG_ON(maxlen == 0);
+
+        if (gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
+                return 0;
+
+        bsize = gfs2_is_dir(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)
+                        return 0;
+
+                error = build_height(inode, height);
+                if (error)
+                        return error;
+        }
+
+        find_metapath(ip, lblock, mp);
+        end_of_metadata = ip->i_di.di_height - 1;
+
+        error = gfs2_meta_inode_buffer(ip, &bh);
+        if (error)
+                return error;
+
+        for (x = 0; x < end_of_metadata; x++) {
+                lookup_block(ip, bh, x, mp, create, &new, &dblock);
+                brelse(bh);
+                if (!dblock)
+                        return 0;
+
+                error = gfs2_meta_indirect_buffer(ip, x+1, dblock, new, &bh);
+                if (error)
+                        return error;
+        }
+
+        boundary = lookup_block(ip, bh, end_of_metadata, mp, create, &new, &dblock);
+        clear_buffer_mapped(bh_map);
+        clear_buffer_new(bh_map);
+        clear_buffer_boundary(bh_map);
+
+        if (dblock) {
+                map_bh(bh_map, inode->i_sb, dblock);
+                if (boundary)
+                        set_buffer_boundary(bh);
+                if (new) {
+                        struct buffer_head *dibh;
+                        error = gfs2_meta_inode_buffer(ip, &dibh);
+                        if (!error) {
+                                gfs2_trans_add_bh(ip->i_gl, dibh, 1);
+                                gfs2_dinode_out(&ip->i_di, dibh->b_data);
+                                brelse(dibh);
+                        }
+                        set_buffer_new(bh_map);
+                        goto out_brelse;
+                }
+                while(--maxlen && !buffer_boundary(bh_map)) {
+                        u64 eblock;
+
+                        mp->mp_list[end_of_metadata]++;
+                        boundary = lookup_block(ip, bh, end_of_metadata, mp, 0, &new, &eblock);
+                        if (eblock != ++dblock)
+                                break;
+                        bh_map->b_size += (1 << inode->i_blkbits);
+                        if (boundary)
+                                set_buffer_boundary(bh_map);
+                }
+        }
+out_brelse:
+        brelse(bh);
+        return 0;
+}
+
+
+static inline void bmap_lock(struct inode *inode, int create)
+{
+        struct gfs2_inode *ip = GFS2_I(inode);
+        if (create)
+                down_write(&ip->i_rw_mutex);
+        else
+                down_read(&ip->i_rw_mutex);
+}
+
+static inline void bmap_unlock(struct inode *inode, int create)
+{
+        struct gfs2_inode *ip = GFS2_I(inode);
+        if (create)
+                up_write(&ip->i_rw_mutex);
+        else
+                up_read(&ip->i_rw_mutex);
+}
+
+int gfs2_block_map(struct inode *inode, u64 lblock, int create,
+                   struct buffer_head *bh, unsigned int maxlen)
+{
+        struct metapath mp;
+        int ret;
+
+        bmap_lock(inode, create);
+        ret = gfs2_block_pointers(inode, lblock, create, bh, &mp, maxlen);
+        bmap_unlock(inode, create);
+        return ret;
+}
+
+int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen)
+{
+        struct metapath mp;
+        struct buffer_head bh = { .b_state = 0, .b_blocknr = 0, .b_size = 0 };
+        int ret;
+        int create = *new;
+
+        BUG_ON(!extlen);
+        BUG_ON(!dblock);
+        BUG_ON(!new);
+
+        bmap_lock(inode, create);
+        ret = gfs2_block_pointers(inode, lblock, create, &bh, &mp, 32);
+        bmap_unlock(inode, create);
+        *extlen = bh.b_size >> inode->i_blkbits;
+        *dblock = bh.b_blocknr;
+        if (buffer_new(&bh))
+                *new = 1;
+        else
+                *new = 0;
+        return ret;
+}
+
+/**
+ * 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,
+                          u64 block, int first, block_call_t bc,
+                          void *data)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        struct buffer_head *bh = NULL;
+        u64 *top, *bottom;
+        u64 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 = (u64 *)(bh->b_data + sizeof(struct gfs2_dinode)) + mp->mp_list[0];
+                bottom = (u64 *)(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 = (u64 *)(bh->b_data + mh_size) +
+                                  (first ? mp->mp_list[height] : 0);
+
+                bottom = (u64 *)(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, u64 *top, u64 *bottom,
+                    unsigned int height, void *data)
+{
+        struct strip_mine *sm = data;
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        struct gfs2_rgrp_list rlist;
+        u64 bn, bstart;
+        u32 blen;
+        u64 *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);
+        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 = rlist.rl_ghs[x].gh_gl->gl_object;
+                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, 1);
+        gfs2_trans_add_bh(ip->i_gl, bh, 1);
+
+        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, u64 size)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        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, 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->i_inode, 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, 1);
+        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;
+}
+
+
+/**
+ * gfs2_block_truncate_page - Deal with zeroing out data for truncate
+ *
+ * This is partly borrowed from ext3.
+ */
+static int gfs2_block_truncate_page(struct address_space *mapping)
+{
+        struct inode *inode = mapping->host;
+        struct gfs2_inode *ip = GFS2_I(inode);
+        struct gfs2_sbd *sdp = GFS2_SB(inode);
+        loff_t from = inode->i_size;
+        unsigned long index = from >> PAGE_CACHE_SHIFT;
+        unsigned offset = from & (PAGE_CACHE_SIZE-1);
+        unsigned blocksize, iblock, length, pos;
+        struct buffer_head *bh;
+        struct page *page;
+        void *kaddr;
+        int err;
+
+        page = grab_cache_page(mapping, index);
+        if (!page)
+                return 0;
+
+        blocksize = inode->i_sb->s_blocksize;
+        length = blocksize - (offset & (blocksize - 1));
+        iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
+
+        if (!page_has_buffers(page))
+                create_empty_buffers(page, blocksize, 0);
+
+        /* Find the buffer that contains "offset" */
+        bh = page_buffers(page);
+        pos = blocksize;
+        while (offset >= pos) {
+                bh = bh->b_this_page;
+                iblock++;
+                pos += blocksize;
+        }
+
+        err = 0;
+
+        if (!buffer_mapped(bh)) {
+                gfs2_get_block(inode, iblock, bh, 0);
+                /* unmapped? It's a hole - nothing to do */
+                if (!buffer_mapped(bh))
+                        goto unlock;
+        }
+
+        /* Ok, it's mapped. Make sure it's up-to-date */
+        if (PageUptodate(page))
+                set_buffer_uptodate(bh);
+
+        if (!buffer_uptodate(bh)) {
+                err = -EIO;
+                ll_rw_block(READ, 1, &bh);
+                wait_on_buffer(bh);
+                /* Uhhuh. Read error. Complain and punt. */
+                if (!buffer_uptodate(bh))
+                        goto unlock;
+        }
+
+        if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip))
+                gfs2_trans_add_bh(ip->i_gl, bh, 0);
+
+        kaddr = kmap_atomic(page, KM_USER0);
+        memset(kaddr + offset, 0, length);
+        flush_dcache_page(page);
+        kunmap_atomic(kaddr, KM_USER0);
+
+unlock:
+        unlock_page(page);
+        page_cache_release(page);
+        return err;
+}
+
+static int trunc_start(struct gfs2_inode *ip, u64 size)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        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, 1);
+                gfs2_dinode_out(&ip->i_di, dibh->b_data);
+                gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + size);
+                error = 1;
+
+        } else {
+                if (size & (u64)(sdp->sd_sb.sb_bsize - 1))
+                        error = gfs2_block_truncate_page(ip->i_inode.i_mapping);
+
+                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, 1);
+                        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, u64 size)
+{
+        unsigned int height = ip->i_di.di_height;
+        u64 lblock;
+        struct metapath mp;
+        int error;
+
+        if (!size)
+                lblock = 0;
+        else
+                lblock = (size - 1) >> GFS2_SB(&ip->i_inode)->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 = GFS2_SB(&ip->i_inode);
+        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, 1);
+        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, u64 size)
+{
+        int error;
+
+        error = trunc_start(ip, size);
+        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 given 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, u64 size)
+{
+        int error;
+
+        if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), 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);
+
+        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 = GFS2_SB(&ip->i_inode);
+        unsigned int tmp;
+
+        if (gfs2_is_dir(ip)) {
+                *data_blocks = DIV_ROUND_UP(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_ROUND_UP(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, u64 offset,
+                              unsigned int len, int *alloc_required)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+        u64 lblock, lblock_stop, dblock;
+        u32 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_dir(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_extent_map(&ip->i_inode, lblock, &new, &dblock, &extlen);
+                if (error)
+                        return error;
+
+                if (!dblock) {
+                        *alloc_required = 1;
+                        return 0;
+                }
+        }
+
+        return 0;
+}
+