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    Subject[PATCH 1/9] extents for ext4
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    Date

    Add extent map support to ext4. Patch from Alex Tomas.

    On disk extents format:
    /*
    * this is extent on-disk structure
    * it's used at the bottom of the tree
    */
    struct ext3_extent {
    __le32 ee_block; /* first logical block extent covers */
    __le16 ee_len; /* number of blocks covered by extent */
    __le16 ee_start_hi; /* high 16 bits of physical block */
    __le32 ee_start; /* low 32 bigs of physical block */
    };

    Signed-Off-By: Alex Tomas <alex@clusterfs.com>
    Signed-Off-By: Mingming Cao <cmm@us.ibm.com>



    ---

    linux-2.6.18-rc4-ming/fs/ext4/Makefile | 2
    linux-2.6.18-rc4-ming/fs/ext4/dir.c | 3
    linux-2.6.18-rc4-ming/fs/ext4/extents.c | 2075 ++++++++++++++++++
    linux-2.6.18-rc4-ming/fs/ext4/ialloc.c | 11
    linux-2.6.18-rc4-ming/fs/ext4/inode.c | 17
    linux-2.6.18-rc4-ming/fs/ext4/ioctl.c | 1
    linux-2.6.18-rc4-ming/fs/ext4/super.c | 10
    linux-2.6.18-rc4-ming/include/linux/ext4_fs.h | 31
    linux-2.6.18-rc4-ming/include/linux/ext4_fs_extents.h | 196 +
    linux-2.6.18-rc4-ming/include/linux/ext4_fs_i.h | 13
    linux-2.6.18-rc4-ming/include/linux/ext4_fs_sb.h | 10
    linux-2.6.18-rc4-ming/include/linux/ext4_jbd2.h | 15
    12 files changed, 2366 insertions(+), 18 deletions(-)

    diff -puN fs/ext4/dir.c~ext4-extents fs/ext4/dir.c
    --- linux-2.6.18-rc4/fs/ext4/dir.c~ext4-extents 2006-08-09 15:41:44.192226487 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/dir.c 2006-08-09 15:41:44.296227329 -0700
    @@ -131,8 +131,7 @@ static int ext4_readdir(struct file * fi
    struct buffer_head *bh = NULL;

    map_bh.b_state = 0;
    - err = ext4_get_blocks_handle(NULL, inode, blk, 1,
    - &map_bh, 0, 0);
    + err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0);
    if (err > 0) {
    page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
    &filp->f_ra,
    diff -puN /dev/null fs/ext4/extents.c
    --- /dev/null 2006-08-08 14:57:22.983223272 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/extents.c 2006-08-09 15:41:44.303227386 -0700
    @@ -0,0 +1,2075 @@
    +/*
    + * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
    + * Written by Alex Tomas <alex@clusterfs.com>
    + *
    + * Architecture independence:
    + * Copyright (c) 2005, Bull S.A.
    + * Written by Pierre Peiffer <pierre.peiffer@bull.net>
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 as
    + * published by the Free Software Foundation.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public Licens
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
    + */
    +
    +/*
    + * Extents support for EXT4
    + *
    + * TODO:
    + * - ext4*_error() should be used in some situations
    + * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
    + * - smart tree reduction
    + */
    +
    +#include <linux/module.h>
    +#include <linux/fs.h>
    +#include <linux/time.h>
    +#include <linux/ext4_jbd2.h>
    +#include <linux/jbd.h>
    +#include <linux/smp_lock.h>
    +#include <linux/highuid.h>
    +#include <linux/pagemap.h>
    +#include <linux/quotaops.h>
    +#include <linux/string.h>
    +#include <linux/slab.h>
    +#include <linux/ext4_fs_extents.h>
    +#include <asm/uaccess.h>
    +
    +
    +static int ext4_ext_check_header(const char *function, struct inode *inode,
    + struct ext4_extent_header *eh)
    +{
    + const char *error_msg = NULL;
    +
    + if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
    + error_msg = "invalid magic";
    + goto corrupted;
    + }
    + if (unlikely(eh->eh_max == 0)) {
    + error_msg = "invalid eh_max";
    + goto corrupted;
    + }
    + if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
    + error_msg = "invalid eh_entries";
    + goto corrupted;
    + }
    + return 0;
    +
    +corrupted:
    + ext4_error(inode->i_sb, function,
    + "bad header in inode #%lu: %s - magic %x, "
    + "entries %u, max %u, depth %u",
    + inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
    + le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
    + le16_to_cpu(eh->eh_depth));
    +
    + return -EIO;
    +}
    +
    +static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
    +{
    + int err;
    +
    + if (handle->h_buffer_credits > needed)
    + return handle;
    + if (!ext4_journal_extend(handle, needed))
    + return handle;
    + err = ext4_journal_restart(handle, needed);
    +
    + return handle;
    +}
    +
    +/*
    + * could return:
    + * - EROFS
    + * - ENOMEM
    + */
    +static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path)
    +{
    + if (path->p_bh) {
    + /* path points to block */
    + return ext4_journal_get_write_access(handle, path->p_bh);
    + }
    + /* path points to leaf/index in inode body */
    + /* we use in-core data, no need to protect them */
    + return 0;
    +}
    +
    +/*
    + * could return:
    + * - EROFS
    + * - ENOMEM
    + * - EIO
    + */
    +static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path)
    +{
    + int err;
    + if (path->p_bh) {
    + /* path points to block */
    + err = ext4_journal_dirty_metadata(handle, path->p_bh);
    + } else {
    + /* path points to leaf/index in inode body */
    + err = ext4_mark_inode_dirty(handle, inode);
    + }
    + return err;
    +}
    +
    +static int ext4_ext_find_goal(struct inode *inode,
    + struct ext4_ext_path *path,
    + unsigned long block)
    +{
    + struct ext4_inode_info *ei = EXT4_I(inode);
    + unsigned long bg_start;
    + unsigned long colour;
    + int depth;
    +
    + if (path) {
    + struct ext4_extent *ex;
    + depth = path->p_depth;
    +
    + /* try to predict block placement */
    + if ((ex = path[depth].p_ext))
    + return le32_to_cpu(ex->ee_start)
    + + (block - le32_to_cpu(ex->ee_block));
    +
    + /* it looks index is empty
    + * try to find starting from index itself */
    + if (path[depth].p_bh)
    + return path[depth].p_bh->b_blocknr;
    + }
    +
    + /* OK. use inode's group */
    + bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
    + le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
    + colour = (current->pid % 16) *
    + (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
    + return bg_start + colour + block;
    +}
    +
    +static int
    +ext4_ext_new_block(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path,
    + struct ext4_extent *ex, int *err)
    +{
    + int goal, newblock;
    +
    + goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
    + newblock = ext4_new_block(handle, inode, goal, err);
    + return newblock;
    +}
    +
    +static inline int ext4_ext_space_block(struct inode *inode)
    +{
    + int size;
    +
    + size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
    + / sizeof(struct ext4_extent);
    +#ifdef AGRESSIVE_TEST
    + if (size > 6)
    + size = 6;
    +#endif
    + return size;
    +}
    +
    +static inline int ext4_ext_space_block_idx(struct inode *inode)
    +{
    + int size;
    +
    + size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
    + / sizeof(struct ext4_extent_idx);
    +#ifdef AGRESSIVE_TEST
    + if (size > 5)
    + size = 5;
    +#endif
    + return size;
    +}
    +
    +static inline int ext4_ext_space_root(struct inode *inode)
    +{
    + int size;
    +
    + size = sizeof(EXT4_I(inode)->i_data);
    + size -= sizeof(struct ext4_extent_header);
    + size /= sizeof(struct ext4_extent);
    +#ifdef AGRESSIVE_TEST
    + if (size > 3)
    + size = 3;
    +#endif
    + return size;
    +}
    +
    +static inline int ext4_ext_space_root_idx(struct inode *inode)
    +{
    + int size;
    +
    + size = sizeof(EXT4_I(inode)->i_data);
    + size -= sizeof(struct ext4_extent_header);
    + size /= sizeof(struct ext4_extent_idx);
    +#ifdef AGRESSIVE_TEST
    + if (size > 4)
    + size = 4;
    +#endif
    + return size;
    +}
    +
    +#ifdef EXT_DEBUG
    +static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
    +{
    + int k, l = path->p_depth;
    +
    + ext_debug("path:");
    + for (k = 0; k <= l; k++, path++) {
    + if (path->p_idx) {
    + ext_debug(" %d->%d", le32_to_cpu(path->p_idx->ei_block),
    + le32_to_cpu(path->p_idx->ei_leaf));
    + } else if (path->p_ext) {
    + ext_debug(" %d:%d:%d",
    + le32_to_cpu(path->p_ext->ee_block),
    + le16_to_cpu(path->p_ext->ee_len),
    + le32_to_cpu(path->p_ext->ee_start));
    + } else
    + ext_debug(" []");
    + }
    + ext_debug("\n");
    +}
    +
    +static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
    +{
    + int depth = ext_depth(inode);
    + struct ext4_extent_header *eh;
    + struct ext4_extent *ex;
    + int i;
    +
    + if (!path)
    + return;
    +
    + eh = path[depth].p_hdr;
    + ex = EXT_FIRST_EXTENT(eh);
    +
    + for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
    + ext_debug("%d:%d:%d ", le32_to_cpu(ex->ee_block),
    + le16_to_cpu(ex->ee_len),
    + le32_to_cpu(ex->ee_start));
    + }
    + ext_debug("\n");
    +}
    +#else
    +#define ext4_ext_show_path(inode,path)
    +#define ext4_ext_show_leaf(inode,path)
    +#endif
    +
    +static void ext4_ext_drop_refs(struct ext4_ext_path *path)
    +{
    + int depth = path->p_depth;
    + int i;
    +
    + for (i = 0; i <= depth; i++, path++)
    + if (path->p_bh) {
    + brelse(path->p_bh);
    + path->p_bh = NULL;
    + }
    +}
    +
    +/*
    + * binary search for closest index by given block
    + */
    +static void
    +ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
    +{
    + struct ext4_extent_header *eh = path->p_hdr;
    + struct ext4_extent_idx *r, *l, *m;
    +
    + BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
    + BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
    + BUG_ON(le16_to_cpu(eh->eh_entries) <= 0);
    +
    + ext_debug("binsearch for %d(idx): ", block);
    +
    + l = EXT_FIRST_INDEX(eh) + 1;
    + r = EXT_FIRST_INDEX(eh) + le16_to_cpu(eh->eh_entries) - 1;
    + while (l <= r) {
    + m = l + (r - l) / 2;
    + if (block < le32_to_cpu(m->ei_block))
    + r = m - 1;
    + else
    + l = m + 1;
    + ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ei_block,
    + m, m->ei_block, r, r->ei_block);
    + }
    +
    + path->p_idx = l - 1;
    + ext_debug(" -> %d->%d ", le32_to_cpu(path->p_idx->ei_block),
    + le32_to_cpu(path->p_idx->ei_leaf));
    +
    +#ifdef CHECK_BINSEARCH
    + {
    + struct ext4_extent_idx *chix, *ix;
    + int k;
    +
    + chix = ix = EXT_FIRST_INDEX(eh);
    + for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
    + if (k != 0 &&
    + le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
    + printk("k=%d, ix=0x%p, first=0x%p\n", k,
    + ix, EXT_FIRST_INDEX(eh));
    + printk("%u <= %u\n",
    + le32_to_cpu(ix->ei_block),
    + le32_to_cpu(ix[-1].ei_block));
    + }
    + BUG_ON(k && le32_to_cpu(ix->ei_block)
    + <= le32_to_cpu(ix[-1].ei_block));
    + if (block < le32_to_cpu(ix->ei_block))
    + break;
    + chix = ix;
    + }
    + BUG_ON(chix != path->p_idx);
    + }
    +#endif
    +
    +}
    +
    +/*
    + * binary search for closest extent by given block
    + */
    +static void
    +ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
    +{
    + struct ext4_extent_header *eh = path->p_hdr;
    + struct ext4_extent *r, *l, *m;
    +
    + BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
    + BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
    +
    + if (eh->eh_entries == 0) {
    + /*
    + * this leaf is empty yet:
    + * we get such a leaf in split/add case
    + */
    + return;
    + }
    +
    + ext_debug("binsearch for %d: ", block);
    +
    + l = EXT_FIRST_EXTENT(eh) + 1;
    + r = EXT_FIRST_EXTENT(eh) + le16_to_cpu(eh->eh_entries) - 1;
    +
    + while (l <= r) {
    + m = l + (r - l) / 2;
    + if (block < le32_to_cpu(m->ee_block))
    + r = m - 1;
    + else
    + l = m + 1;
    + ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ee_block,
    + m, m->ee_block, r, r->ee_block);
    + }
    +
    + path->p_ext = l - 1;
    + ext_debug(" -> %d:%d:%d ",
    + le32_to_cpu(path->p_ext->ee_block),
    + le32_to_cpu(path->p_ext->ee_start),
    + le16_to_cpu(path->p_ext->ee_len));
    +
    +#ifdef CHECK_BINSEARCH
    + {
    + struct ext4_extent *chex, *ex;
    + int k;
    +
    + chex = ex = EXT_FIRST_EXTENT(eh);
    + for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
    + BUG_ON(k && le32_to_cpu(ex->ee_block)
    + <= le32_to_cpu(ex[-1].ee_block));
    + if (block < le32_to_cpu(ex->ee_block))
    + break;
    + chex = ex;
    + }
    + BUG_ON(chex != path->p_ext);
    + }
    +#endif
    +
    +}
    +
    +int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
    +{
    + struct ext4_extent_header *eh;
    +
    + eh = ext_inode_hdr(inode);
    + eh->eh_depth = 0;
    + eh->eh_entries = 0;
    + eh->eh_magic = EXT4_EXT_MAGIC;
    + eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
    + ext4_mark_inode_dirty(handle, inode);
    + ext4_ext_invalidate_cache(inode);
    + return 0;
    +}
    +
    +struct ext4_ext_path *
    +ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
    +{
    + struct ext4_extent_header *eh;
    + struct buffer_head *bh;
    + short int depth, i, ppos = 0, alloc = 0;
    +
    + eh = ext_inode_hdr(inode);
    + BUG_ON(eh == NULL);
    + if (ext4_ext_check_header(__FUNCTION__, inode, eh))
    + return ERR_PTR(-EIO);
    +
    + i = depth = ext_depth(inode);
    +
    + /* account possible depth increase */
    + if (!path) {
    + path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 2),
    + GFP_NOFS);
    + if (!path)
    + return ERR_PTR(-ENOMEM);
    + alloc = 1;
    + }
    + memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
    + path[0].p_hdr = eh;
    +
    + /* walk through the tree */
    + while (i) {
    + ext_debug("depth %d: num %d, max %d\n",
    + ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
    + ext4_ext_binsearch_idx(inode, path + ppos, block);
    + path[ppos].p_block = le32_to_cpu(path[ppos].p_idx->ei_leaf);
    + path[ppos].p_depth = i;
    + path[ppos].p_ext = NULL;
    +
    + bh = sb_bread(inode->i_sb, path[ppos].p_block);
    + if (!bh)
    + goto err;
    +
    + eh = ext_block_hdr(bh);
    + ppos++;
    + BUG_ON(ppos > depth);
    + path[ppos].p_bh = bh;
    + path[ppos].p_hdr = eh;
    + i--;
    +
    + if (ext4_ext_check_header(__FUNCTION__, inode, eh))
    + goto err;
    + }
    +
    + path[ppos].p_depth = i;
    + path[ppos].p_hdr = eh;
    + path[ppos].p_ext = NULL;
    + path[ppos].p_idx = NULL;
    +
    + if (ext4_ext_check_header(__FUNCTION__, inode, eh))
    + goto err;
    +
    + /* find extent */
    + ext4_ext_binsearch(inode, path + ppos, block);
    +
    + ext4_ext_show_path(inode, path);
    +
    + return path;
    +
    +err:
    + ext4_ext_drop_refs(path);
    + if (alloc)
    + kfree(path);
    + return ERR_PTR(-EIO);
    +}
    +
    +/*
    + * insert new index [logical;ptr] into the block at cupr
    + * it check where to insert: before curp or after curp
    + */
    +static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *curp,
    + int logical, int ptr)
    +{
    + struct ext4_extent_idx *ix;
    + int len, err;
    +
    + if ((err = ext4_ext_get_access(handle, inode, curp)))
    + return err;
    +
    + BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
    + len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
    + if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
    + /* insert after */
    + if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
    + len = (len - 1) * sizeof(struct ext4_extent_idx);
    + len = len < 0 ? 0 : len;
    + ext_debug("insert new index %d after: %d. "
    + "move %d from 0x%p to 0x%p\n",
    + logical, ptr, len,
    + (curp->p_idx + 1), (curp->p_idx + 2));
    + memmove(curp->p_idx + 2, curp->p_idx + 1, len);
    + }
    + ix = curp->p_idx + 1;
    + } else {
    + /* insert before */
    + len = len * sizeof(struct ext4_extent_idx);
    + len = len < 0 ? 0 : len;
    + ext_debug("insert new index %d before: %d. "
    + "move %d from 0x%p to 0x%p\n",
    + logical, ptr, len,
    + curp->p_idx, (curp->p_idx + 1));
    + memmove(curp->p_idx + 1, curp->p_idx, len);
    + ix = curp->p_idx;
    + }
    +
    + ix->ei_block = cpu_to_le32(logical);
    + ix->ei_leaf = cpu_to_le32(ptr);
    + curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
    +
    + BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
    + > le16_to_cpu(curp->p_hdr->eh_max));
    + BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
    +
    + err = ext4_ext_dirty(handle, inode, curp);
    + ext4_std_error(inode->i_sb, err);
    +
    + return err;
    +}
    +
    +/*
    + * routine inserts new subtree into the path, using free index entry
    + * at depth 'at:
    + * - allocates all needed blocks (new leaf and all intermediate index blocks)
    + * - makes decision where to split
    + * - moves remaining extens and index entries (right to the split point)
    + * into the newly allocated blocks
    + * - initialize subtree
    + */
    +static int ext4_ext_split(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path,
    + struct ext4_extent *newext, int at)
    +{
    + struct buffer_head *bh = NULL;
    + int depth = ext_depth(inode);
    + struct ext4_extent_header *neh;
    + struct ext4_extent_idx *fidx;
    + struct ext4_extent *ex;
    + int i = at, k, m, a;
    + unsigned long newblock, oldblock;
    + __le32 border;
    + int *ablocks = NULL; /* array of allocated blocks */
    + int err = 0;
    +
    + /* make decision: where to split? */
    + /* FIXME: now desicion is simplest: at current extent */
    +
    + /* if current leaf will be splitted, then we should use
    + * border from split point */
    + BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
    + if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
    + border = path[depth].p_ext[1].ee_block;
    + ext_debug("leaf will be splitted."
    + " next leaf starts at %d\n",
    + le32_to_cpu(border));
    + } else {
    + border = newext->ee_block;
    + ext_debug("leaf will be added."
    + " next leaf starts at %d\n",
    + le32_to_cpu(border));
    + }
    +
    + /*
    + * if error occurs, then we break processing
    + * and turn filesystem read-only. so, index won't
    + * be inserted and tree will be in consistent
    + * state. next mount will repair buffers too
    + */
    +
    + /*
    + * get array to track all allocated blocks
    + * we need this to handle errors and free blocks
    + * upon them
    + */
    + ablocks = kmalloc(sizeof(unsigned long) * depth, GFP_NOFS);
    + if (!ablocks)
    + return -ENOMEM;
    + memset(ablocks, 0, sizeof(unsigned long) * depth);
    +
    + /* allocate all needed blocks */
    + ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
    + for (a = 0; a < depth - at; a++) {
    + newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
    + if (newblock == 0)
    + goto cleanup;
    + ablocks[a] = newblock;
    + }
    +
    + /* initialize new leaf */
    + newblock = ablocks[--a];
    + BUG_ON(newblock == 0);
    + bh = sb_getblk(inode->i_sb, newblock);
    + if (!bh) {
    + err = -EIO;
    + goto cleanup;
    + }
    + lock_buffer(bh);
    +
    + if ((err = ext4_journal_get_create_access(handle, bh)))
    + goto cleanup;
    +
    + neh = ext_block_hdr(bh);
    + neh->eh_entries = 0;
    + neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
    + neh->eh_magic = EXT4_EXT_MAGIC;
    + neh->eh_depth = 0;
    + ex = EXT_FIRST_EXTENT(neh);
    +
    + /* move remain of path[depth] to the new leaf */
    + BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
    + /* start copy from next extent */
    + /* TODO: we could do it by single memmove */
    + m = 0;
    + path[depth].p_ext++;
    + while (path[depth].p_ext <=
    + EXT_MAX_EXTENT(path[depth].p_hdr)) {
    + ext_debug("move %d:%d:%d in new leaf %lu\n",
    + le32_to_cpu(path[depth].p_ext->ee_block),
    + le32_to_cpu(path[depth].p_ext->ee_start),
    + le16_to_cpu(path[depth].p_ext->ee_len),
    + newblock);
    + /*memmove(ex++, path[depth].p_ext++,
    + sizeof(struct ext4_extent));
    + neh->eh_entries++;*/
    + path[depth].p_ext++;
    + m++;
    + }
    + if (m) {
    + memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
    + neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
    + }
    +
    + set_buffer_uptodate(bh);
    + unlock_buffer(bh);
    +
    + if ((err = ext4_journal_dirty_metadata(handle, bh)))
    + goto cleanup;
    + brelse(bh);
    + bh = NULL;
    +
    + /* correct old leaf */
    + if (m) {
    + if ((err = ext4_ext_get_access(handle, inode, path + depth)))
    + goto cleanup;
    + path[depth].p_hdr->eh_entries =
    + cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
    + if ((err = ext4_ext_dirty(handle, inode, path + depth)))
    + goto cleanup;
    +
    + }
    +
    + /* create intermediate indexes */
    + k = depth - at - 1;
    + BUG_ON(k < 0);
    + if (k)
    + ext_debug("create %d intermediate indices\n", k);
    + /* insert new index into current index block */
    + /* current depth stored in i var */
    + i = depth - 1;
    + while (k--) {
    + oldblock = newblock;
    + newblock = ablocks[--a];
    + bh = sb_getblk(inode->i_sb, newblock);
    + if (!bh) {
    + err = -EIO;
    + goto cleanup;
    + }
    + lock_buffer(bh);
    +
    + if ((err = ext4_journal_get_create_access(handle, bh)))
    + goto cleanup;
    +
    + neh = ext_block_hdr(bh);
    + neh->eh_entries = cpu_to_le16(1);
    + neh->eh_magic = EXT4_EXT_MAGIC;
    + neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
    + neh->eh_depth = cpu_to_le16(depth - i);
    + fidx = EXT_FIRST_INDEX(neh);
    + fidx->ei_block = border;
    + fidx->ei_leaf = cpu_to_le32(oldblock);
    +
    + ext_debug("int.index at %d (block %lu): %lu -> %lu\n", i,
    + newblock, (unsigned long) le32_to_cpu(border),
    + oldblock);
    + /* copy indexes */
    + m = 0;
    + path[i].p_idx++;
    +
    + ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
    + EXT_MAX_INDEX(path[i].p_hdr));
    + BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
    + EXT_LAST_INDEX(path[i].p_hdr));
    + while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
    + ext_debug("%d: move %d:%d in new index %lu\n", i,
    + le32_to_cpu(path[i].p_idx->ei_block),
    + le32_to_cpu(path[i].p_idx->ei_leaf),
    + newblock);
    + /*memmove(++fidx, path[i].p_idx++,
    + sizeof(struct ext4_extent_idx));
    + neh->eh_entries++;
    + BUG_ON(neh->eh_entries > neh->eh_max);*/
    + path[i].p_idx++;
    + m++;
    + }
    + if (m) {
    + memmove(++fidx, path[i].p_idx - m,
    + sizeof(struct ext4_extent_idx) * m);
    + neh->eh_entries =
    + cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
    + }
    + set_buffer_uptodate(bh);
    + unlock_buffer(bh);
    +
    + if ((err = ext4_journal_dirty_metadata(handle, bh)))
    + goto cleanup;
    + brelse(bh);
    + bh = NULL;
    +
    + /* correct old index */
    + if (m) {
    + err = ext4_ext_get_access(handle, inode, path + i);
    + if (err)
    + goto cleanup;
    + path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
    + err = ext4_ext_dirty(handle, inode, path + i);
    + if (err)
    + goto cleanup;
    + }
    +
    + i--;
    + }
    +
    + /* insert new index */
    + if (err)
    + goto cleanup;
    +
    + err = ext4_ext_insert_index(handle, inode, path + at,
    + le32_to_cpu(border), newblock);
    +
    +cleanup:
    + if (bh) {
    + if (buffer_locked(bh))
    + unlock_buffer(bh);
    + brelse(bh);
    + }
    +
    + if (err) {
    + /* free all allocated blocks in error case */
    + for (i = 0; i < depth; i++) {
    + if (!ablocks[i])
    + continue;
    + ext4_free_blocks(handle, inode, ablocks[i], 1);
    + }
    + }
    + kfree(ablocks);
    +
    + return err;
    +}
    +
    +/*
    + * routine implements tree growing procedure:
    + * - allocates new block
    + * - moves top-level data (index block or leaf) into the new block
    + * - initialize new top-level, creating index that points to the
    + * just created block
    + */
    +static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path,
    + struct ext4_extent *newext)
    +{
    + struct ext4_ext_path *curp = path;
    + struct ext4_extent_header *neh;
    + struct ext4_extent_idx *fidx;
    + struct buffer_head *bh;
    + unsigned long newblock;
    + int err = 0;
    +
    + newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
    + if (newblock == 0)
    + return err;
    +
    + bh = sb_getblk(inode->i_sb, newblock);
    + if (!bh) {
    + err = -EIO;
    + ext4_std_error(inode->i_sb, err);
    + return err;
    + }
    + lock_buffer(bh);
    +
    + if ((err = ext4_journal_get_create_access(handle, bh))) {
    + unlock_buffer(bh);
    + goto out;
    + }
    +
    + /* move top-level index/leaf into new block */
    + memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
    +
    + /* set size of new block */
    + neh = ext_block_hdr(bh);
    + /* old root could have indexes or leaves
    + * so calculate e_max right way */
    + if (ext_depth(inode))
    + neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
    + else
    + neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
    + neh->eh_magic = EXT4_EXT_MAGIC;
    + set_buffer_uptodate(bh);
    + unlock_buffer(bh);
    +
    + if ((err = ext4_journal_dirty_metadata(handle, bh)))
    + goto out;
    +
    + /* create index in new top-level index: num,max,pointer */
    + if ((err = ext4_ext_get_access(handle, inode, curp)))
    + goto out;
    +
    + curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
    + curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
    + curp->p_hdr->eh_entries = cpu_to_le16(1);
    + curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
    + /* FIXME: it works, but actually path[0] can be index */
    + curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
    + curp->p_idx->ei_leaf = cpu_to_le32(newblock);
    +
    + neh = ext_inode_hdr(inode);
    + fidx = EXT_FIRST_INDEX(neh);
    + ext_debug("new root: num %d(%d), lblock %d, ptr %d\n",
    + le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
    + le32_to_cpu(fidx->ei_block), le32_to_cpu(fidx->ei_leaf));
    +
    + neh->eh_depth = cpu_to_le16(path->p_depth + 1);
    + err = ext4_ext_dirty(handle, inode, curp);
    +out:
    + brelse(bh);
    +
    + return err;
    +}
    +
    +/*
    + * routine finds empty index and adds new leaf. if no free index found
    + * then it requests in-depth growing
    + */
    +static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path,
    + struct ext4_extent *newext)
    +{
    + struct ext4_ext_path *curp;
    + int depth, i, err = 0;
    +
    +repeat:
    + i = depth = ext_depth(inode);
    +
    + /* walk up to the tree and look for free index entry */
    + curp = path + depth;
    + while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
    + i--;
    + curp--;
    + }
    +
    + /* we use already allocated block for index block
    + * so, subsequent data blocks should be contigoues */
    + if (EXT_HAS_FREE_INDEX(curp)) {
    + /* if we found index with free entry, then use that
    + * entry: create all needed subtree and add new leaf */
    + err = ext4_ext_split(handle, inode, path, newext, i);
    +
    + /* refill path */
    + ext4_ext_drop_refs(path);
    + path = ext4_ext_find_extent(inode,
    + le32_to_cpu(newext->ee_block),
    + path);
    + if (IS_ERR(path))
    + err = PTR_ERR(path);
    + } else {
    + /* tree is full, time to grow in depth */
    + err = ext4_ext_grow_indepth(handle, inode, path, newext);
    + if (err)
    + goto out;
    +
    + /* refill path */
    + ext4_ext_drop_refs(path);
    + path = ext4_ext_find_extent(inode,
    + le32_to_cpu(newext->ee_block),
    + path);
    + if (IS_ERR(path)) {
    + err = PTR_ERR(path);
    + goto out;
    + }
    +
    + /*
    + * only first (depth 0 -> 1) produces free space
    + * in all other cases we have to split growed tree
    + */
    + depth = ext_depth(inode);
    + if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
    + /* now we need split */
    + goto repeat;
    + }
    + }
    +
    +out:
    + return err;
    +}
    +
    +/*
    + * returns allocated block in subsequent extent or EXT_MAX_BLOCK
    + * NOTE: it consider block number from index entry as
    + * allocated block. thus, index entries have to be consistent
    + * with leafs
    + */
    +static unsigned long
    +ext4_ext_next_allocated_block(struct ext4_ext_path *path)
    +{
    + int depth;
    +
    + BUG_ON(path == NULL);
    + depth = path->p_depth;
    +
    + if (depth == 0 && path->p_ext == NULL)
    + return EXT_MAX_BLOCK;
    +
    + while (depth >= 0) {
    + if (depth == path->p_depth) {
    + /* leaf */
    + if (path[depth].p_ext !=
    + EXT_LAST_EXTENT(path[depth].p_hdr))
    + return le32_to_cpu(path[depth].p_ext[1].ee_block);
    + } else {
    + /* index */
    + if (path[depth].p_idx !=
    + EXT_LAST_INDEX(path[depth].p_hdr))
    + return le32_to_cpu(path[depth].p_idx[1].ei_block);
    + }
    + depth--;
    + }
    +
    + return EXT_MAX_BLOCK;
    +}
    +
    +/*
    + * returns first allocated block from next leaf or EXT_MAX_BLOCK
    + */
    +static unsigned ext4_ext_next_leaf_block(struct inode *inode,
    + struct ext4_ext_path *path)
    +{
    + int depth;
    +
    + BUG_ON(path == NULL);
    + depth = path->p_depth;
    +
    + /* zero-tree has no leaf blocks at all */
    + if (depth == 0)
    + return EXT_MAX_BLOCK;
    +
    + /* go to index block */
    + depth--;
    +
    + while (depth >= 0) {
    + if (path[depth].p_idx !=
    + EXT_LAST_INDEX(path[depth].p_hdr))
    + return le32_to_cpu(path[depth].p_idx[1].ei_block);
    + depth--;
    + }
    +
    + return EXT_MAX_BLOCK;
    +}
    +
    +/*
    + * if leaf gets modified and modified extent is first in the leaf
    + * then we have to correct all indexes above
    + * TODO: do we need to correct tree in all cases?
    + */
    +int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path)
    +{
    + struct ext4_extent_header *eh;
    + int depth = ext_depth(inode);
    + struct ext4_extent *ex;
    + __le32 border;
    + int k, err = 0;
    +
    + eh = path[depth].p_hdr;
    + ex = path[depth].p_ext;
    + BUG_ON(ex == NULL);
    + BUG_ON(eh == NULL);
    +
    + if (depth == 0) {
    + /* there is no tree at all */
    + return 0;
    + }
    +
    + if (ex != EXT_FIRST_EXTENT(eh)) {
    + /* we correct tree if first leaf got modified only */
    + return 0;
    + }
    +
    + /*
    + * TODO: we need correction if border is smaller then current one
    + */
    + k = depth - 1;
    + border = path[depth].p_ext->ee_block;
    + if ((err = ext4_ext_get_access(handle, inode, path + k)))
    + return err;
    + path[k].p_idx->ei_block = border;
    + if ((err = ext4_ext_dirty(handle, inode, path + k)))
    + return err;
    +
    + while (k--) {
    + /* change all left-side indexes */
    + if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
    + break;
    + if ((err = ext4_ext_get_access(handle, inode, path + k)))
    + break;
    + path[k].p_idx->ei_block = border;
    + if ((err = ext4_ext_dirty(handle, inode, path + k)))
    + break;
    + }
    +
    + return err;
    +}
    +
    +static int inline
    +ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
    + struct ext4_extent *ex2)
    +{
    + /* FIXME: 48bit support */
    + if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len)
    + != le32_to_cpu(ex2->ee_block))
    + return 0;
    +
    +#ifdef AGRESSIVE_TEST
    + if (le16_to_cpu(ex1->ee_len) >= 4)
    + return 0;
    +#endif
    +
    + if (le32_to_cpu(ex1->ee_start) + le16_to_cpu(ex1->ee_len)
    + == le32_to_cpu(ex2->ee_start))
    + return 1;
    + return 0;
    +}
    +
    +/*
    + * this routine tries to merge requsted extent into the existing
    + * extent or inserts requested extent as new one into the tree,
    + * creating new leaf in no-space case
    + */
    +int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path,
    + struct ext4_extent *newext)
    +{
    + struct ext4_extent_header * eh;
    + struct ext4_extent *ex, *fex;
    + struct ext4_extent *nearex; /* nearest extent */
    + struct ext4_ext_path *npath = NULL;
    + int depth, len, err, next;
    +
    + BUG_ON(newext->ee_len == 0);
    + depth = ext_depth(inode);
    + ex = path[depth].p_ext;
    + BUG_ON(path[depth].p_hdr == NULL);
    +
    + /* try to insert block into found extent and return */
    + if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
    + ext_debug("append %d block to %d:%d (from %d)\n",
    + le16_to_cpu(newext->ee_len),
    + le32_to_cpu(ex->ee_block),
    + le16_to_cpu(ex->ee_len),
    + le32_to_cpu(ex->ee_start));
    + if ((err = ext4_ext_get_access(handle, inode, path + depth)))
    + return err;
    + ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
    + + le16_to_cpu(newext->ee_len));
    + eh = path[depth].p_hdr;
    + nearex = ex;
    + goto merge;
    + }
    +
    +repeat:
    + depth = ext_depth(inode);
    + eh = path[depth].p_hdr;
    + if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
    + goto has_space;
    +
    + /* probably next leaf has space for us? */
    + fex = EXT_LAST_EXTENT(eh);
    + next = ext4_ext_next_leaf_block(inode, path);
    + if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
    + && next != EXT_MAX_BLOCK) {
    + ext_debug("next leaf block - %d\n", next);
    + BUG_ON(npath != NULL);
    + npath = ext4_ext_find_extent(inode, next, NULL);
    + if (IS_ERR(npath))
    + return PTR_ERR(npath);
    + BUG_ON(npath->p_depth != path->p_depth);
    + eh = npath[depth].p_hdr;
    + if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
    + ext_debug("next leaf isnt full(%d)\n",
    + le16_to_cpu(eh->eh_entries));
    + path = npath;
    + goto repeat;
    + }
    + ext_debug("next leaf has no free space(%d,%d)\n",
    + le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
    + }
    +
    + /*
    + * there is no free space in found leaf
    + * we're gonna add new leaf in the tree
    + */
    + err = ext4_ext_create_new_leaf(handle, inode, path, newext);
    + if (err)
    + goto cleanup;
    + depth = ext_depth(inode);
    + eh = path[depth].p_hdr;
    +
    +has_space:
    + nearex = path[depth].p_ext;
    +
    + if ((err = ext4_ext_get_access(handle, inode, path + depth)))
    + goto cleanup;
    +
    + if (!nearex) {
    + /* there is no extent in this leaf, create first one */
    + ext_debug("first extent in the leaf: %d:%d:%d\n",
    + le32_to_cpu(newext->ee_block),
    + le32_to_cpu(newext->ee_start),
    + le16_to_cpu(newext->ee_len));
    + path[depth].p_ext = EXT_FIRST_EXTENT(eh);
    + } else if (le32_to_cpu(newext->ee_block)
    + > le32_to_cpu(nearex->ee_block)) {
    +/* BUG_ON(newext->ee_block == nearex->ee_block); */
    + if (nearex != EXT_LAST_EXTENT(eh)) {
    + len = EXT_MAX_EXTENT(eh) - nearex;
    + len = (len - 1) * sizeof(struct ext4_extent);
    + len = len < 0 ? 0 : len;
    + ext_debug("insert %d:%d:%d after: nearest 0x%p, "
    + "move %d from 0x%p to 0x%p\n",
    + le32_to_cpu(newext->ee_block),
    + le32_to_cpu(newext->ee_start),
    + le16_to_cpu(newext->ee_len),
    + nearex, len, nearex + 1, nearex + 2);
    + memmove(nearex + 2, nearex + 1, len);
    + }
    + path[depth].p_ext = nearex + 1;
    + } else {
    + BUG_ON(newext->ee_block == nearex->ee_block);
    + len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
    + len = len < 0 ? 0 : len;
    + ext_debug("insert %d:%d:%d before: nearest 0x%p, "
    + "move %d from 0x%p to 0x%p\n",
    + le32_to_cpu(newext->ee_block),
    + le32_to_cpu(newext->ee_start),
    + le16_to_cpu(newext->ee_len),
    + nearex, len, nearex + 1, nearex + 2);
    + memmove(nearex + 1, nearex, len);
    + path[depth].p_ext = nearex;
    + }
    +
    + eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
    + nearex = path[depth].p_ext;
    + nearex->ee_block = newext->ee_block;
    + nearex->ee_start = newext->ee_start;
    + nearex->ee_len = newext->ee_len;
    + /* FIXME: support for large fs */
    + nearex->ee_start_hi = 0;
    +
    +merge:
    + /* try to merge extents to the right */
    + while (nearex < EXT_LAST_EXTENT(eh)) {
    + if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
    + break;
    + /* merge with next extent! */
    + nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
    + + le16_to_cpu(nearex[1].ee_len));
    + if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
    + len = (EXT_LAST_EXTENT(eh) - nearex - 1)
    + * sizeof(struct ext4_extent);
    + memmove(nearex + 1, nearex + 2, len);
    + }
    + eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
    + BUG_ON(eh->eh_entries == 0);
    + }
    +
    + /* try to merge extents to the left */
    +
    + /* time to correct all indexes above */
    + err = ext4_ext_correct_indexes(handle, inode, path);
    + if (err)
    + goto cleanup;
    +
    + err = ext4_ext_dirty(handle, inode, path + depth);
    +
    +cleanup:
    + if (npath) {
    + ext4_ext_drop_refs(npath);
    + kfree(npath);
    + }
    + ext4_ext_tree_changed(inode);
    + ext4_ext_invalidate_cache(inode);
    + return err;
    +}
    +
    +int ext4_ext_walk_space(struct inode *inode, unsigned long block,
    + unsigned long num, ext_prepare_callback func,
    + void *cbdata)
    +{
    + struct ext4_ext_path *path = NULL;
    + struct ext4_ext_cache cbex;
    + struct ext4_extent *ex;
    + unsigned long next, start = 0, end = 0;
    + unsigned long last = block + num;
    + int depth, exists, err = 0;
    +
    + BUG_ON(func == NULL);
    + BUG_ON(inode == NULL);
    +
    + while (block < last && block != EXT_MAX_BLOCK) {
    + num = last - block;
    + /* find extent for this block */
    + path = ext4_ext_find_extent(inode, block, path);
    + if (IS_ERR(path)) {
    + err = PTR_ERR(path);
    + path = NULL;
    + break;
    + }
    +
    + depth = ext_depth(inode);
    + BUG_ON(path[depth].p_hdr == NULL);
    + ex = path[depth].p_ext;
    + next = ext4_ext_next_allocated_block(path);
    +
    + exists = 0;
    + if (!ex) {
    + /* there is no extent yet, so try to allocate
    + * all requested space */
    + start = block;
    + end = block + num;
    + } else if (le32_to_cpu(ex->ee_block) > block) {
    + /* need to allocate space before found extent */
    + start = block;
    + end = le32_to_cpu(ex->ee_block);
    + if (block + num < end)
    + end = block + num;
    + } else if (block >=
    + le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) {
    + /* need to allocate space after found extent */
    + start = block;
    + end = block + num;
    + if (end >= next)
    + end = next;
    + } else if (block >= le32_to_cpu(ex->ee_block)) {
    + /*
    + * some part of requested space is covered
    + * by found extent
    + */
    + start = block;
    + end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len);
    + if (block + num < end)
    + end = block + num;
    + exists = 1;
    + } else {
    + BUG();
    + }
    + BUG_ON(end <= start);
    +
    + if (!exists) {
    + cbex.ec_block = start;
    + cbex.ec_len = end - start;
    + cbex.ec_start = 0;
    + cbex.ec_type = EXT4_EXT_CACHE_GAP;
    + } else {
    + cbex.ec_block = le32_to_cpu(ex->ee_block);
    + cbex.ec_len = le16_to_cpu(ex->ee_len);
    + cbex.ec_start = le32_to_cpu(ex->ee_start);
    + cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
    + }
    +
    + BUG_ON(cbex.ec_len == 0);
    + err = func(inode, path, &cbex, cbdata);
    + ext4_ext_drop_refs(path);
    +
    + if (err < 0)
    + break;
    + if (err == EXT_REPEAT)
    + continue;
    + else if (err == EXT_BREAK) {
    + err = 0;
    + break;
    + }
    +
    + if (ext_depth(inode) != depth) {
    + /* depth was changed. we have to realloc path */
    + kfree(path);
    + path = NULL;
    + }
    +
    + block = cbex.ec_block + cbex.ec_len;
    + }
    +
    + if (path) {
    + ext4_ext_drop_refs(path);
    + kfree(path);
    + }
    +
    + return err;
    +}
    +
    +static inline void
    +ext4_ext_put_in_cache(struct inode *inode, __u32 block,
    + __u32 len, __u32 start, int type)
    +{
    + struct ext4_ext_cache *cex;
    + BUG_ON(len == 0);
    + cex = &EXT4_I(inode)->i_cached_extent;
    + cex->ec_type = type;
    + cex->ec_block = block;
    + cex->ec_len = len;
    + cex->ec_start = start;
    +}
    +
    +/*
    + * this routine calculate boundaries of the gap requested block fits into
    + * and cache this gap
    + */
    +static inline void
    +ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
    + unsigned long block)
    +{
    + int depth = ext_depth(inode);
    + unsigned long lblock, len;
    + struct ext4_extent *ex;
    +
    + ex = path[depth].p_ext;
    + if (ex == NULL) {
    + /* there is no extent yet, so gap is [0;-] */
    + lblock = 0;
    + len = EXT_MAX_BLOCK;
    + ext_debug("cache gap(whole file):");
    + } else if (block < le32_to_cpu(ex->ee_block)) {
    + lblock = block;
    + len = le32_to_cpu(ex->ee_block) - block;
    + ext_debug("cache gap(before): %lu [%lu:%lu]",
    + (unsigned long) block,
    + (unsigned long) le32_to_cpu(ex->ee_block),
    + (unsigned long) le16_to_cpu(ex->ee_len));
    + } else if (block >= le32_to_cpu(ex->ee_block)
    + + le16_to_cpu(ex->ee_len)) {
    + lblock = le32_to_cpu(ex->ee_block)
    + + le16_to_cpu(ex->ee_len);
    + len = ext4_ext_next_allocated_block(path);
    + ext_debug("cache gap(after): [%lu:%lu] %lu",
    + (unsigned long) le32_to_cpu(ex->ee_block),
    + (unsigned long) le16_to_cpu(ex->ee_len),
    + (unsigned long) block);
    + BUG_ON(len == lblock);
    + len = len - lblock;
    + } else {
    + lblock = len = 0;
    + BUG();
    + }
    +
    + ext_debug(" -> %lu:%lu\n", (unsigned long) lblock, len);
    + ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
    +}
    +
    +static inline int
    +ext4_ext_in_cache(struct inode *inode, unsigned long block,
    + struct ext4_extent *ex)
    +{
    + struct ext4_ext_cache *cex;
    +
    + cex = &EXT4_I(inode)->i_cached_extent;
    +
    + /* has cache valid data? */
    + if (cex->ec_type == EXT4_EXT_CACHE_NO)
    + return EXT4_EXT_CACHE_NO;
    +
    + BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
    + cex->ec_type != EXT4_EXT_CACHE_EXTENT);
    + if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
    + ex->ee_block = cpu_to_le32(cex->ec_block);
    + ex->ee_start = cpu_to_le32(cex->ec_start);
    + ex->ee_len = cpu_to_le16(cex->ec_len);
    + ext_debug("%lu cached by %lu:%lu:%lu\n",
    + (unsigned long) block,
    + (unsigned long) cex->ec_block,
    + (unsigned long) cex->ec_len,
    + (unsigned long) cex->ec_start);
    + return cex->ec_type;
    + }
    +
    + /* not in cache */
    + return EXT4_EXT_CACHE_NO;
    +}
    +
    +/*
    + * routine removes index from the index block
    + * it's used in truncate case only. thus all requests are for
    + * last index in the block only
    + */
    +int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path)
    +{
    + struct buffer_head *bh;
    + int err;
    + unsigned long leaf;
    +
    + /* free index block */
    + path--;
    + leaf = le32_to_cpu(path->p_idx->ei_leaf);
    + BUG_ON(path->p_hdr->eh_entries == 0);
    + if ((err = ext4_ext_get_access(handle, inode, path)))
    + return err;
    + path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
    + if ((err = ext4_ext_dirty(handle, inode, path)))
    + return err;
    + ext_debug("index is empty, remove it, free block %lu\n", leaf);
    + bh = sb_find_get_block(inode->i_sb, leaf);
    + ext4_forget(handle, 1, inode, bh, leaf);
    + ext4_free_blocks(handle, inode, leaf, 1);
    + return err;
    +}
    +
    +/*
    + * This routine returns max. credits extent tree can consume.
    + * It should be OK for low-performance paths like ->writepage()
    + * To allow many writing process to fit a single transaction,
    + * caller should calculate credits under truncate_mutex and
    + * pass actual path.
    + */
    +int inline ext4_ext_calc_credits_for_insert(struct inode *inode,
    + struct ext4_ext_path *path)
    +{
    + int depth, needed;
    +
    + if (path) {
    + /* probably there is space in leaf? */
    + depth = ext_depth(inode);
    + if (le16_to_cpu(path[depth].p_hdr->eh_entries)
    + < le16_to_cpu(path[depth].p_hdr->eh_max))
    + return 1;
    + }
    +
    + /*
    + * given 32bit logical block (4294967296 blocks), max. tree
    + * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
    + * let's also add one more level for imbalance.
    + */
    + depth = 5;
    +
    + /* allocation of new data block(s) */
    + needed = 2;
    +
    + /*
    + * tree can be full, so it'd need to grow in depth:
    + * allocation + old root + new root
    + */
    + needed += 2 + 1 + 1;
    +
    + /*
    + * Index split can happen, we'd need:
    + * allocate intermediate indexes (bitmap + group)
    + * + change two blocks at each level, but root (already included)
    + */
    + needed = (depth * 2) + (depth * 2);
    +
    + /* any allocation modifies superblock */
    + needed += 1;
    +
    + return needed;
    +}
    +
    +static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
    + struct ext4_extent *ex,
    + unsigned long from, unsigned long to)
    +{
    + struct buffer_head *bh;
    + int i;
    +
    +#ifdef EXTENTS_STATS
    + {
    + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
    + unsigned short ee_len = le16_to_cpu(ex->ee_len);
    + spin_lock(&sbi->s_ext_stats_lock);
    + sbi->s_ext_blocks += ee_len;
    + sbi->s_ext_extents++;
    + if (ee_len < sbi->s_ext_min)
    + sbi->s_ext_min = ee_len;
    + if (ee_len > sbi->s_ext_max)
    + sbi->s_ext_max = ee_len;
    + if (ext_depth(inode) > sbi->s_depth_max)
    + sbi->s_depth_max = ext_depth(inode);
    + spin_unlock(&sbi->s_ext_stats_lock);
    + }
    +#endif
    + if (from >= le32_to_cpu(ex->ee_block)
    + && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
    + /* tail removal */
    + unsigned long num, start;
    + num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
    + start = le32_to_cpu(ex->ee_start) + le16_to_cpu(ex->ee_len) - num;
    + ext_debug("free last %lu blocks starting %lu\n", num, start);
    + for (i = 0; i < num; i++) {
    + bh = sb_find_get_block(inode->i_sb, start + i);
    + ext4_forget(handle, 0, inode, bh, start + i);
    + }
    + ext4_free_blocks(handle, inode, start, num);
    + } else if (from == le32_to_cpu(ex->ee_block)
    + && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
    + printk("strange request: removal %lu-%lu from %u:%u\n",
    + from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
    + } else {
    + printk("strange request: removal(2) %lu-%lu from %u:%u\n",
    + from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
    + }
    + return 0;
    +}
    +
    +static int
    +ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
    + struct ext4_ext_path *path, unsigned long start)
    +{
    + int err = 0, correct_index = 0;
    + int depth = ext_depth(inode), credits;
    + struct ext4_extent_header *eh;
    + unsigned a, b, block, num;
    + unsigned long ex_ee_block;
    + unsigned short ex_ee_len;
    + struct ext4_extent *ex;
    +
    + ext_debug("truncate since %lu in leaf\n", start);
    + if (!path[depth].p_hdr)
    + path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
    + eh = path[depth].p_hdr;
    + BUG_ON(eh == NULL);
    + BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
    + BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
    +
    + /* find where to start removing */
    + ex = EXT_LAST_EXTENT(eh);
    +
    + ex_ee_block = le32_to_cpu(ex->ee_block);
    + ex_ee_len = le16_to_cpu(ex->ee_len);
    +
    + while (ex >= EXT_FIRST_EXTENT(eh) &&
    + ex_ee_block + ex_ee_len > start) {
    + ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
    + path[depth].p_ext = ex;
    +
    + a = ex_ee_block > start ? ex_ee_block : start;
    + b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
    + ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
    +
    + ext_debug(" border %u:%u\n", a, b);
    +
    + if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
    + block = 0;
    + num = 0;
    + BUG();
    + } else if (a != ex_ee_block) {
    + /* remove tail of the extent */
    + block = ex_ee_block;
    + num = a - block;
    + } else if (b != ex_ee_block + ex_ee_len - 1) {
    + /* remove head of the extent */
    + block = a;
    + num = b - a;
    + /* there is no "make a hole" API yet */
    + BUG();
    + } else {
    + /* remove whole extent: excellent! */
    + block = ex_ee_block;
    + num = 0;
    + BUG_ON(a != ex_ee_block);
    + BUG_ON(b != ex_ee_block + ex_ee_len - 1);
    + }
    +
    + /* at present, extent can't cross block group */
    + /* leaf + bitmap + group desc + sb + inode */
    + credits = 5;
    + if (ex == EXT_FIRST_EXTENT(eh)) {
    + correct_index = 1;
    + credits += (ext_depth(inode)) + 1;
    + }
    +#ifdef CONFIG_QUOTA
    + credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
    +#endif
    +
    + handle = ext4_ext_journal_restart(handle, credits);
    + if (IS_ERR(handle)) {
    + err = PTR_ERR(handle);
    + goto out;
    + }
    +
    + err = ext4_ext_get_access(handle, inode, path + depth);
    + if (err)
    + goto out;
    +
    + err = ext4_remove_blocks(handle, inode, ex, a, b);
    + if (err)
    + goto out;
    +
    + if (num == 0) {
    + /* this extent is removed entirely mark slot unused */
    + ex->ee_start = 0;
    + eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
    + }
    +
    + ex->ee_block = cpu_to_le32(block);
    + ex->ee_len = cpu_to_le16(num);
    +
    + err = ext4_ext_dirty(handle, inode, path + depth);
    + if (err)
    + goto out;
    +
    + ext_debug("new extent: %u:%u:%u\n", block, num,
    + le32_to_cpu(ex->ee_start));
    + ex--;
    + ex_ee_block = le32_to_cpu(ex->ee_block);
    + ex_ee_len = le16_to_cpu(ex->ee_len);
    + }
    +
    + if (correct_index && eh->eh_entries)
    + err = ext4_ext_correct_indexes(handle, inode, path);
    +
    + /* if this leaf is free, then we should
    + * remove it from index block above */
    + if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
    + err = ext4_ext_rm_idx(handle, inode, path + depth);
    +
    +out:
    + return err;
    +}
    +
    +/*
    + * returns 1 if current index have to be freed (even partial)
    + */
    +static int inline
    +ext4_ext_more_to_rm(struct ext4_ext_path *path)
    +{
    + BUG_ON(path->p_idx == NULL);
    +
    + if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
    + return 0;
    +
    + /*
    + * if truncate on deeper level happened it it wasn't partial
    + * so we have to consider current index for truncation
    + */
    + if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
    + return 0;
    + return 1;
    +}
    +
    +int ext4_ext_remove_space(struct inode *inode, unsigned long start)
    +{
    + struct super_block *sb = inode->i_sb;
    + int depth = ext_depth(inode);
    + struct ext4_ext_path *path;
    + handle_t *handle;
    + int i = 0, err = 0;
    +
    + ext_debug("truncate since %lu\n", start);
    +
    + /* probably first extent we're gonna free will be last in block */
    + handle = ext4_journal_start(inode, depth + 1);
    + if (IS_ERR(handle))
    + return PTR_ERR(handle);
    +
    + ext4_ext_invalidate_cache(inode);
    +
    + /*
    + * we start scanning from right side freeing all the blocks
    + * after i_size and walking into the deep
    + */
    + path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
    + if (path == NULL) {
    + ext4_journal_stop(handle);
    + return -ENOMEM;
    + }
    + memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
    + path[0].p_hdr = ext_inode_hdr(inode);
    + if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) {
    + err = -EIO;
    + goto out;
    + }
    + path[0].p_depth = depth;
    +
    + while (i >= 0 && err == 0) {
    + if (i == depth) {
    + /* this is leaf block */
    + err = ext4_ext_rm_leaf(handle, inode, path, start);
    + /* root level have p_bh == NULL, brelse() eats this */
    + brelse(path[i].p_bh);
    + path[i].p_bh = NULL;
    + i--;
    + continue;
    + }
    +
    + /* this is index block */
    + if (!path[i].p_hdr) {
    + ext_debug("initialize header\n");
    + path[i].p_hdr = ext_block_hdr(path[i].p_bh);
    + if (ext4_ext_check_header(__FUNCTION__, inode,
    + path[i].p_hdr)) {
    + err = -EIO;
    + goto out;
    + }
    + }
    +
    + BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries)
    + > le16_to_cpu(path[i].p_hdr->eh_max));
    + BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
    +
    + if (!path[i].p_idx) {
    + /* this level hasn't touched yet */
    + path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
    + path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
    + ext_debug("init index ptr: hdr 0x%p, num %d\n",
    + path[i].p_hdr,
    + le16_to_cpu(path[i].p_hdr->eh_entries));
    + } else {
    + /* we've already was here, see at next index */
    + path[i].p_idx--;
    + }
    +
    + ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
    + i, EXT_FIRST_INDEX(path[i].p_hdr),
    + path[i].p_idx);
    + if (ext4_ext_more_to_rm(path + i)) {
    + /* go to the next level */
    + ext_debug("move to level %d (block %d)\n",
    + i + 1, le32_to_cpu(path[i].p_idx->ei_leaf));
    + memset(path + i + 1, 0, sizeof(*path));
    + path[i+1].p_bh =
    + sb_bread(sb, le32_to_cpu(path[i].p_idx->ei_leaf));
    + if (!path[i+1].p_bh) {
    + /* should we reset i_size? */
    + err = -EIO;
    + break;
    + }
    +
    + /* put actual number of indexes to know is this
    + * number got changed at the next iteration */
    + path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
    + i++;
    + } else {
    + /* we finish processing this index, go up */
    + if (path[i].p_hdr->eh_entries == 0 && i > 0) {
    + /* index is empty, remove it
    + * handle must be already prepared by the
    + * truncatei_leaf() */
    + err = ext4_ext_rm_idx(handle, inode, path + i);
    + }
    + /* root level have p_bh == NULL, brelse() eats this */
    + brelse(path[i].p_bh);
    + path[i].p_bh = NULL;
    + i--;
    + ext_debug("return to level %d\n", i);
    + }
    + }
    +
    + /* TODO: flexible tree reduction should be here */
    + if (path->p_hdr->eh_entries == 0) {
    + /*
    + * truncate to zero freed all the tree
    + * so, we need to correct eh_depth
    + */
    + err = ext4_ext_get_access(handle, inode, path);
    + if (err == 0) {
    + ext_inode_hdr(inode)->eh_depth = 0;
    + ext_inode_hdr(inode)->eh_max =
    + cpu_to_le16(ext4_ext_space_root(inode));
    + err = ext4_ext_dirty(handle, inode, path);
    + }
    + }
    +out:
    + ext4_ext_tree_changed(inode);
    + ext4_ext_drop_refs(path);
    + kfree(path);
    + ext4_journal_stop(handle);
    +
    + return err;
    +}
    +
    +/*
    + * called at mount time
    + */
    +void ext4_ext_init(struct super_block *sb)
    +{
    + /*
    + * possible initialization would be here
    + */
    +
    + if (test_opt(sb, EXTENTS)) {
    + printk("EXT4-fs: file extents enabled");
    +#ifdef AGRESSIVE_TEST
    + printk(", agressive tests");
    +#endif
    +#ifdef CHECK_BINSEARCH
    + printk(", check binsearch");
    +#endif
    +#ifdef EXTENTS_STATS
    + printk(", stats");
    +#endif
    + printk("\n");
    +#ifdef EXTENTS_STATS
    + spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
    + EXT4_SB(sb)->s_ext_min = 1 << 30;
    + EXT4_SB(sb)->s_ext_max = 0;
    +#endif
    + }
    +}
    +
    +/*
    + * called at umount time
    + */
    +void ext4_ext_release(struct super_block *sb)
    +{
    + if (!test_opt(sb, EXTENTS))
    + return;
    +
    +#ifdef EXTENTS_STATS
    + if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
    + struct ext4_sb_info *sbi = EXT4_SB(sb);
    + printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
    + sbi->s_ext_blocks, sbi->s_ext_extents,
    + sbi->s_ext_blocks / sbi->s_ext_extents);
    + printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
    + sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
    + }
    +#endif
    +}
    +
    +int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, sector_t iblock,
    + unsigned long max_blocks, struct buffer_head *bh_result,
    + int create, int extend_disksize)
    +{
    + struct ext4_ext_path *path = NULL;
    + struct ext4_extent newex, *ex;
    + int goal, newblock, err = 0, depth;
    + unsigned long allocated = 0;
    +
    + __clear_bit(BH_New, &bh_result->b_state);
    + ext_debug("blocks %d/%lu requested for inode %u\n", (int) iblock,
    + max_blocks, (unsigned) inode->i_ino);
    + mutex_lock(&EXT4_I(inode)->truncate_mutex);
    +
    + /* check in cache */
    + if ((goal = ext4_ext_in_cache(inode, iblock, &newex))) {
    + if (goal == EXT4_EXT_CACHE_GAP) {
    + if (!create) {
    + /* block isn't allocated yet and
    + * user don't want to allocate it */
    + goto out2;
    + }
    + /* we should allocate requested block */
    + } else if (goal == EXT4_EXT_CACHE_EXTENT) {
    + /* block is already allocated */
    + newblock = iblock
    + - le32_to_cpu(newex.ee_block)
    + + le32_to_cpu(newex.ee_start);
    + /* number of remain blocks in the extent */
    + allocated = le16_to_cpu(newex.ee_len) -
    + (iblock - le32_to_cpu(newex.ee_block));
    + goto out;
    + } else {
    + BUG();
    + }
    + }
    +
    + /* find extent for this block */
    + path = ext4_ext_find_extent(inode, iblock, NULL);
    + if (IS_ERR(path)) {
    + err = PTR_ERR(path);
    + path = NULL;
    + goto out2;
    + }
    +
    + depth = ext_depth(inode);
    +
    + /*
    + * consistent leaf must not be empty
    + * this situations is possible, though, _during_ tree modification
    + * this is why assert can't be put in ext4_ext_find_extent()
    + */
    + BUG_ON(path[depth].p_ext == NULL && depth != 0);
    +
    + if ((ex = path[depth].p_ext)) {
    + unsigned long ee_block = le32_to_cpu(ex->ee_block);
    + unsigned long ee_start = le32_to_cpu(ex->ee_start);
    + unsigned short ee_len = le16_to_cpu(ex->ee_len);
    + /* if found exent covers block, simple return it */
    + if (iblock >= ee_block && iblock < ee_block + ee_len) {
    + newblock = iblock - ee_block + ee_start;
    + /* number of remain blocks in the extent */
    + allocated = ee_len - (iblock - ee_block);
    + ext_debug("%d fit into %lu:%d -> %d\n", (int) iblock,
    + ee_block, ee_len, newblock);
    + ext4_ext_put_in_cache(inode, ee_block, ee_len,
    + ee_start, EXT4_EXT_CACHE_EXTENT);
    + goto out;
    + }
    + }
    +
    + /*
    + * requested block isn't allocated yet
    + * we couldn't try to create block if create flag is zero
    + */
    + if (!create) {
    + /* put just found gap into cache to speedup subsequest reqs */
    + ext4_ext_put_gap_in_cache(inode, path, iblock);
    + goto out2;
    + }
    + /*
    + * Okay, we need to do block allocation. Lazily initialize the block
    + * allocation info here if necessary
    + */
    + if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
    + ext4_init_block_alloc_info(inode);
    +
    + /* allocate new block */
    + goal = ext4_ext_find_goal(inode, path, iblock);
    + allocated = max_blocks;
    + newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
    + if (!newblock)
    + goto out2;
    + ext_debug("allocate new block: goal %d, found %d/%lu\n",
    + goal, newblock, allocated);
    +
    + /* try to insert new extent into found leaf and return */
    + newex.ee_block = cpu_to_le32(iblock);
    + newex.ee_start = cpu_to_le32(newblock);
    + newex.ee_len = cpu_to_le16(allocated);
    + err = ext4_ext_insert_extent(handle, inode, path, &newex);
    + if (err)
    + goto out2;
    +
    + if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
    + EXT4_I(inode)->i_disksize = inode->i_size;
    +
    + /* previous routine could use block we allocated */
    + newblock = le32_to_cpu(newex.ee_start);
    + __set_bit(BH_New, &bh_result->b_state);
    +
    + ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
    + EXT4_EXT_CACHE_EXTENT);
    +out:
    + if (allocated > max_blocks)
    + allocated = max_blocks;
    + ext4_ext_show_leaf(inode, path);
    + __set_bit(BH_Mapped, &bh_result->b_state);
    + bh_result->b_bdev = inode->i_sb->s_bdev;
    + bh_result->b_blocknr = newblock;
    +out2:
    + if (path) {
    + ext4_ext_drop_refs(path);
    + kfree(path);
    + }
    + mutex_unlock(&EXT4_I(inode)->truncate_mutex);
    +
    + return err ? err : allocated;
    +}
    +
    +void ext4_ext_truncate(struct inode * inode, struct page *page)
    +{
    + struct address_space *mapping = inode->i_mapping;
    + struct super_block *sb = inode->i_sb;
    + unsigned long last_block;
    + handle_t *handle;
    + int err = 0;
    +
    + /*
    + * probably first extent we're gonna free will be last in block
    + */
    + err = ext4_writepage_trans_blocks(inode) + 3;
    + handle = ext4_journal_start(inode, err);
    + if (IS_ERR(handle)) {
    + if (page) {
    + clear_highpage(page);
    + flush_dcache_page(page);
    + unlock_page(page);
    + page_cache_release(page);
    + }
    + return;
    + }
    +
    + if (page)
    + ext4_block_truncate_page(handle, page, mapping, inode->i_size);
    +
    + mutex_lock(&EXT4_I(inode)->truncate_mutex);
    + ext4_ext_invalidate_cache(inode);
    +
    + /*
    + * TODO: optimization is possible here
    + * probably we need not scaning at all,
    + * because page truncation is enough
    + */
    + if (ext4_orphan_add(handle, inode))
    + goto out_stop;
    +
    + /* we have to know where to truncate from in crash case */
    + EXT4_I(inode)->i_disksize = inode->i_size;
    + ext4_mark_inode_dirty(handle, inode);
    +
    + last_block = (inode->i_size + sb->s_blocksize - 1)
    + >> EXT4_BLOCK_SIZE_BITS(sb);
    + err = ext4_ext_remove_space(inode, last_block);
    +
    + /* In a multi-transaction truncate, we only make the final
    + * transaction synchronous */
    + if (IS_SYNC(inode))
    + handle->h_sync = 1;
    +
    +out_stop:
    + /*
    + * If this was a simple ftruncate(), and the file will remain alive
    + * then we need to clear up the orphan record which we created above.
    + * However, if this was a real unlink then we were called by
    + * ext4_delete_inode(), and we allow that function to clean up the
    + * orphan info for us.
    + */
    + if (inode->i_nlink)
    + ext4_orphan_del(handle, inode);
    +
    + mutex_unlock(&EXT4_I(inode)->truncate_mutex);
    + ext4_journal_stop(handle);
    +}
    +
    +/*
    + * this routine calculate max number of blocks we could modify
    + * in order to allocate new block for an inode
    + */
    +int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
    +{
    + int needed;
    +
    + needed = ext4_ext_calc_credits_for_insert(inode, NULL);
    +
    + /* caller want to allocate num blocks, but note it includes sb */
    + needed = needed * num - (num - 1);
    +
    +#ifdef CONFIG_QUOTA
    + needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
    +#endif
    +
    + return needed;
    +}
    +
    +EXPORT_SYMBOL(ext4_mark_inode_dirty);
    +EXPORT_SYMBOL(ext4_ext_invalidate_cache);
    +EXPORT_SYMBOL(ext4_ext_insert_extent);
    +EXPORT_SYMBOL(ext4_ext_walk_space);
    +EXPORT_SYMBOL(ext4_ext_find_goal);
    +EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert);
    +
    diff -puN fs/ext4/ialloc.c~ext4-extents fs/ext4/ialloc.c
    --- linux-2.6.18-rc4/fs/ext4/ialloc.c~ext4-extents 2006-08-09 15:41:44.196226520 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/ialloc.c 2006-08-09 15:41:44.305227402 -0700
    @@ -616,6 +616,17 @@ got:
    ext4_std_error(sb, err);
    goto fail_free_drop;
    }
    + if (test_opt(sb, EXTENTS)) {
    + EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
    + ext4_ext_tree_init(handle, inode);
    + if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
    + err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
    + if (err) goto fail;
    + EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS);
    + BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "call ext4_journal_dirty_metadata");
    + err = ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
    + }
    + }

    ext4_debug("allocating inode %lu\n", inode->i_ino);
    goto really_out;
    diff -puN fs/ext4/inode.c~ext4-extents fs/ext4/inode.c
    --- linux-2.6.18-rc4/fs/ext4/inode.c~ext4-extents 2006-08-09 15:41:44.200226552 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/inode.c 2006-08-09 15:41:44.310227443 -0700
    @@ -39,8 +39,6 @@
    #include "xattr.h"
    #include "acl.h"

    -static int ext4_writepage_trans_blocks(struct inode *inode);
    -
    /*
    * Test whether an inode is a fast symlink.
    */
    @@ -803,6 +801,7 @@ int ext4_get_blocks_handle(handle_t *han
    ext4_fsblk_t first_block = 0;


    + J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
    J_ASSERT(handle != NULL || create == 0);
    depth = ext4_block_to_path(inode,iblock,offsets,&blocks_to_boundary);

    @@ -983,7 +982,7 @@ static int ext4_get_block(struct inode *

    get_block:
    if (ret == 0) {
    - ret = ext4_get_blocks_handle(handle, inode, iblock,
    + ret = ext4_get_blocks_wrap(handle, inode, iblock,
    max_blocks, bh_result, create, 0);
    if (ret > 0) {
    bh_result->b_size = (ret << inode->i_blkbits);
    @@ -1007,7 +1006,7 @@ struct buffer_head *ext4_getblk(handle_t
    dummy.b_state = 0;
    dummy.b_blocknr = -1000;
    buffer_trace_init(&dummy.b_history);
    - err = ext4_get_blocks_handle(handle, inode, block, 1,
    + err = ext4_get_blocks_wrap(handle, inode, block, 1,
    &dummy, create, 1);
    if (err == 1) {
    err = 0;
    @@ -1755,7 +1754,7 @@ void ext4_set_aops(struct inode *inode)
    * This required during truncate. We need to physically zero the tail end
    * of that block so it doesn't yield old data if the file is later grown.
    */
    -static int ext4_block_truncate_page(handle_t *handle, struct page *page,
    +int ext4_block_truncate_page(handle_t *handle, struct page *page,
    struct address_space *mapping, loff_t from)
    {
    ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
    @@ -2259,6 +2258,9 @@ void ext4_truncate(struct inode *inode)
    return;
    }

    + if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
    + return ext4_ext_truncate(inode, page);
    +
    handle = start_transaction(inode);
    if (IS_ERR(handle)) {
    if (page) {
    @@ -3001,12 +3003,15 @@ err_out:
    * block and work out the exact number of indirects which are touched. Pah.
    */

    -static int ext4_writepage_trans_blocks(struct inode *inode)
    +int ext4_writepage_trans_blocks(struct inode *inode)
    {
    int bpp = ext4_journal_blocks_per_page(inode);
    int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
    int ret;

    + if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
    + return ext4_ext_writepage_trans_blocks(inode, bpp);
    +
    if (ext4_should_journal_data(inode))
    ret = 3 * (bpp + indirects) + 2;
    else
    diff -puN fs/ext4/ioctl.c~ext4-extents fs/ext4/ioctl.c
    --- linux-2.6.18-rc4/fs/ext4/ioctl.c~ext4-extents 2006-08-09 15:41:44.203226576 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/ioctl.c 2006-08-09 15:41:44.311227451 -0700
    @@ -247,7 +247,6 @@ flags_err:
    return err;
    }

    -
    default:
    return -ENOTTY;
    }
    diff -puN fs/ext4/Makefile~ext4-extents fs/ext4/Makefile
    --- linux-2.6.18-rc4/fs/ext4/Makefile~ext4-extents 2006-08-09 15:41:44.247226932 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/Makefile 2006-08-09 15:41:44.311227451 -0700
    @@ -5,7 +5,7 @@
    obj-$(CONFIG_EXT3DEV_FS) += ext3dev.o

    ext3dev-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
    - ioctl.o namei.o super.o symlink.o hash.o resize.o
    + ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o

    ext3dev-$(CONFIG_EXT3DEV_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
    ext3dev-$(CONFIG_EXT3DEV_FS_POSIX_ACL) += acl.o
    diff -puN fs/ext4/super.c~ext4-extents fs/ext4/super.c
    --- linux-2.6.18-rc4/fs/ext4/super.c~ext4-extents 2006-08-09 15:41:44.250226957 -0700
    +++ linux-2.6.18-rc4-ming/fs/ext4/super.c 2006-08-09 15:41:44.316227491 -0700
    @@ -389,6 +389,7 @@ static void ext4_put_super (struct super
    struct ext4_super_block *es = sbi->s_es;
    int i;

    + ext4_ext_release(sb);
    ext4_xattr_put_super(sb);
    jbd2_journal_destroy(sbi->s_journal);
    if (!(sb->s_flags & MS_RDONLY)) {
    @@ -453,6 +454,7 @@ static struct inode *ext4_alloc_inode(st
    #endif
    ei->i_block_alloc_info = NULL;
    ei->vfs_inode.i_version = 1;
    + memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
    return &ei->vfs_inode;
    }

    @@ -635,7 +637,7 @@ enum {
    Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
    Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
    Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
    - Opt_grpquota
    + Opt_grpquota, Opt_extents,
    };

    static match_table_t tokens = {
    @@ -685,6 +687,7 @@ static match_table_t tokens = {
    {Opt_quota, "quota"},
    {Opt_usrquota, "usrquota"},
    {Opt_barrier, "barrier=%u"},
    + {Opt_extents, "extents"},
    {Opt_err, NULL},
    {Opt_resize, "resize"},
    };
    @@ -1017,6 +1020,9 @@ clear_qf_name:
    case Opt_bh:
    clear_opt(sbi->s_mount_opt, NOBH);
    break;
    + case Opt_extents:
    + set_opt (sbi->s_mount_opt, EXTENTS);
    + break;
    default:
    printk (KERN_ERR
    "EXT4-fs: Unrecognized mount option \"%s\" "
    @@ -1742,6 +1748,8 @@ static int ext4_fill_super (struct super
    test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
    "writeback");

    + ext4_ext_init(sb);
    +
    lock_kernel();
    return 0;

    diff -puN /dev/null include/linux/ext4_fs_extents.h
    --- /dev/null 2006-08-08 14:57:22.983223272 -0700
    +++ linux-2.6.18-rc4-ming/include/linux/ext4_fs_extents.h 2006-08-09 15:41:44.317227499 -0700
    @@ -0,0 +1,196 @@
    +/*
    + * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
    + * Written by Alex Tomas <alex@clusterfs.com>
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 as
    + * published by the Free Software Foundation.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public Licens
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
    + */
    +
    +#ifndef _LINUX_EXT4_EXTENTS
    +#define _LINUX_EXT4_EXTENTS
    +
    +#include <linux/ext4_fs.h>
    +
    +/*
    + * with AGRESSIVE_TEST defined capacity of index/leaf blocks
    + * become very little, so index split, in-depth growing and
    + * other hard changes happens much more often
    + * this is for debug purposes only
    + */
    +#define AGRESSIVE_TEST_
    +
    +/*
    + * with EXTENTS_STATS defined number of blocks and extents
    + * are collected in truncate path. they'll be showed at
    + * umount time
    + */
    +#define EXTENTS_STATS__
    +
    +/*
    + * if CHECK_BINSEARCH defined, then results of binary search
    + * will be checked by linear search
    + */
    +#define CHECK_BINSEARCH__
    +
    +/*
    + * if EXT_DEBUG is defined you can use 'extdebug' mount option
    + * to get lots of info what's going on
    + */
    +#define EXT_DEBUG__
    +#ifdef EXT_DEBUG
    +#define ext_debug(a...) printk(a)
    +#else
    +#define ext_debug(a...)
    +#endif
    +
    +/*
    + * if EXT_STATS is defined then stats numbers are collected
    + * these number will be displayed at umount time
    + */
    +#define EXT_STATS_
    +
    +
    +/*
    + * ext4_inode has i_block array (60 bytes total)
    + * first 12 bytes store ext4_extent_header
    + * the remain stores array of ext4_extent
    + */
    +
    +/*
    + * this is extent on-disk structure
    + * it's used at the bottom of the tree
    + */
    +struct ext4_extent {
    + __le32 ee_block; /* first logical block extent covers */
    + __le16 ee_len; /* number of blocks covered by extent */
    + __le16 ee_start_hi; /* high 16 bits of physical block */
    + __le32 ee_start; /* low 32 bigs of physical block */
    +};
    +
    +/*
    + * this is index on-disk structure
    + * it's used at all the levels, but the bottom
    + */
    +struct ext4_extent_idx {
    + __le32 ei_block; /* index covers logical blocks from 'block' */
    + __le32 ei_leaf; /* pointer to the physical block of the next *
    + * level. leaf or next index could bet here */
    + __le16 ei_leaf_hi; /* high 16 bits of physical block */
    + __u16 ei_unused;
    +};
    +
    +/*
    + * each block (leaves and indexes), even inode-stored has header
    + */
    +struct ext4_extent_header {
    + __le16 eh_magic; /* probably will support different formats */
    + __le16 eh_entries; /* number of valid entries */
    + __le16 eh_max; /* capacity of store in entries */
    + __le16 eh_depth; /* has tree real underlaying blocks? */
    + __le32 eh_generation; /* generation of the tree */
    +};
    +
    +#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
    +
    +/*
    + * array of ext4_ext_path contains path to some extent
    + * creation/lookup routines use it for traversal/splitting/etc
    + * truncate uses it to simulate recursive walking
    + */
    +struct ext4_ext_path {
    + __u32 p_block;
    + __u16 p_depth;
    + struct ext4_extent *p_ext;
    + struct ext4_extent_idx *p_idx;
    + struct ext4_extent_header *p_hdr;
    + struct buffer_head *p_bh;
    +};
    +
    +/*
    + * structure for external API
    + */
    +
    +#define EXT4_EXT_CACHE_NO 0
    +#define EXT4_EXT_CACHE_GAP 1
    +#define EXT4_EXT_CACHE_EXTENT 2
    +
    +/*
    + * to be called by ext4_ext_walk_space()
    + * negative retcode - error
    + * positive retcode - signal for ext4_ext_walk_space(), see below
    + * callback must return valid extent (passed or newly created)
    + */
    +typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *,
    + struct ext4_ext_cache *,
    + void *);
    +
    +#define EXT_CONTINUE 0
    +#define EXT_BREAK 1
    +#define EXT_REPEAT 2
    +
    +
    +#define EXT_MAX_BLOCK 0xffffffff
    +
    +
    +#define EXT_FIRST_EXTENT(__hdr__) \
    + ((struct ext4_extent *) (((char *) (__hdr__)) + \
    + sizeof(struct ext4_extent_header)))
    +#define EXT_FIRST_INDEX(__hdr__) \
    + ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
    + sizeof(struct ext4_extent_header)))
    +#define EXT_HAS_FREE_INDEX(__path__) \
    + (le16_to_cpu((__path__)->p_hdr->eh_entries) \
    + < le16_to_cpu((__path__)->p_hdr->eh_max))
    +#define EXT_LAST_EXTENT(__hdr__) \
    + (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
    +#define EXT_LAST_INDEX(__hdr__) \
    + (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
    +#define EXT_MAX_EXTENT(__hdr__) \
    + (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
    +#define EXT_MAX_INDEX(__hdr__) \
    + (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
    +
    +static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
    +{
    + return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
    +}
    +
    +static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
    +{
    + return (struct ext4_extent_header *) bh->b_data;
    +}
    +
    +static inline unsigned short ext_depth(struct inode *inode)
    +{
    + return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
    +}
    +
    +static inline void ext4_ext_tree_changed(struct inode *inode)
    +{
    + EXT4_I(inode)->i_ext_generation++;
    +}
    +
    +static inline void
    +ext4_ext_invalidate_cache(struct inode *inode)
    +{
    + EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
    +}
    +
    +extern int ext4_extent_tree_init(handle_t *, struct inode *);
    +extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
    +extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *);
    +extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *);
    +extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *);
    +
    +#endif /* _LINUX_EXT4_EXTENTS */
    +
    diff -puN include/linux/ext4_fs.h~ext4-extents include/linux/ext4_fs.h
    --- linux-2.6.18-rc4/include/linux/ext4_fs.h~ext4-extents 2006-08-09 15:41:44.282227216 -0700
    +++ linux-2.6.18-rc4-ming/include/linux/ext4_fs.h 2006-08-09 15:41:44.319227515 -0700
    @@ -182,8 +182,9 @@ struct ext4_group_desc
    #define EXT4_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */
    #define EXT4_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/
    #define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */
    +#define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */

    -#define EXT4_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */
    +#define EXT4_FL_USER_VISIBLE 0x000BDFFF /* User visible flags */
    #define EXT4_FL_USER_MODIFIABLE 0x000380FF /* User modifiable flags */

    /*
    @@ -371,6 +372,7 @@ struct ext4_inode {
    #define EXT4_MOUNT_QUOTA 0x80000 /* Some quota option set */
    #define EXT4_MOUNT_USRQUOTA 0x100000 /* "old" user quota */
    #define EXT4_MOUNT_GRPQUOTA 0x200000 /* "old" group quota */
    +#define EXT4_MOUNT_EXTENTS 0x400000 /* Extents support */

    /* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
    #ifndef _LINUX_EXT2_FS_H
    @@ -560,11 +562,13 @@ static inline struct ext4_inode_info *EX
    #define EXT4_FEATURE_INCOMPAT_RECOVER 0x0004 /* Needs recovery */
    #define EXT4_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Journal device */
    #define EXT4_FEATURE_INCOMPAT_META_BG 0x0010
    +#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */

    #define EXT4_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
    #define EXT4_FEATURE_INCOMPAT_SUPP (EXT4_FEATURE_INCOMPAT_FILETYPE| \
    EXT4_FEATURE_INCOMPAT_RECOVER| \
    - EXT4_FEATURE_INCOMPAT_META_BG)
    + EXT4_FEATURE_INCOMPAT_META_BG| \
    + EXT4_FEATURE_INCOMPAT_EXTENTS)
    #define EXT4_FEATURE_RO_COMPAT_SUPP (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
    EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
    EXT4_FEATURE_RO_COMPAT_BTREE_DIR)
    @@ -803,6 +807,9 @@ extern int ext4_get_inode_loc(struct ino
    extern void ext4_truncate (struct inode *);
    extern void ext4_set_inode_flags(struct inode *);
    extern void ext4_set_aops(struct inode *inode);
    +extern int ext4_writepage_trans_blocks(struct inode *);
    +extern int ext4_block_truncate_page(handle_t *handle, struct page *page,
    + struct address_space *mapping, loff_t from);

    /* ioctl.c */
    extern int ext4_ioctl (struct inode *, struct file *, unsigned int,
    @@ -856,6 +863,26 @@ extern struct inode_operations ext4_spec
    extern struct inode_operations ext4_symlink_inode_operations;
    extern struct inode_operations ext4_fast_symlink_inode_operations;

    +/* extents.c */
    +extern int ext4_ext_tree_init(handle_t *handle, struct inode *);
    +extern int ext4_ext_writepage_trans_blocks(struct inode *, int);
    +extern int ext4_ext_get_blocks(handle_t *, struct inode *, sector_t,
    + unsigned long, struct buffer_head *, int, int);
    +extern void ext4_ext_truncate(struct inode *, struct page *);
    +extern void ext4_ext_init(struct super_block *);
    +extern void ext4_ext_release(struct super_block *);
    +static inline int
    +ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
    + unsigned long max_blocks, struct buffer_head *bh,
    + int create, int extend_disksize)
    +{
    + if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
    + return ext4_ext_get_blocks(handle, inode, block, max_blocks,
    + bh, create, extend_disksize);
    + return ext4_get_blocks_handle(handle, inode, block, max_blocks, bh,
    + create, extend_disksize);
    +}
    +

    #endif /* __KERNEL__ */

    diff -puN include/linux/ext4_fs_i.h~ext4-extents include/linux/ext4_fs_i.h
    --- linux-2.6.18-rc4/include/linux/ext4_fs_i.h~ext4-extents 2006-08-09 15:41:44.285227240 -0700
    +++ linux-2.6.18-rc4-ming/include/linux/ext4_fs_i.h 2006-08-09 15:41:44.320227524 -0700
    @@ -65,6 +65,16 @@ struct ext4_block_alloc_info {
    #define rsv_end rsv_window._rsv_end

    /*
    + * storage for cached extent
    + */
    +struct ext4_ext_cache {
    + __u32 ec_start;
    + __u32 ec_block;
    + __u32 ec_len; /* must be 32bit to return holes */
    + __u32 ec_type;
    +};
    +
    +/*
    * third extended file system inode data in memory
    */
    struct ext4_inode_info {
    @@ -142,6 +152,9 @@ struct ext4_inode_info {
    */
    struct mutex truncate_mutex;
    struct inode vfs_inode;
    +
    + unsigned long i_ext_generation;
    + struct ext4_ext_cache i_cached_extent;
    };

    #endif /* _LINUX_EXT4_FS_I */
    diff -puN include/linux/ext4_fs_sb.h~ext4-extents include/linux/ext4_fs_sb.h
    --- linux-2.6.18-rc4/include/linux/ext4_fs_sb.h~ext4-extents 2006-08-09 15:41:44.289227273 -0700
    +++ linux-2.6.18-rc4-ming/include/linux/ext4_fs_sb.h 2006-08-09 15:41:44.320227524 -0700
    @@ -78,6 +78,16 @@ struct ext4_sb_info {
    char *s_qf_names[MAXQUOTAS]; /* Names of quota files with journalled quota */
    int s_jquota_fmt; /* Format of quota to use */
    #endif
    +
    +#ifdef EXTENTS_STATS
    + /* ext4 extents stats */
    + unsigned long s_ext_min;
    + unsigned long s_ext_max;
    + unsigned long s_depth_max;
    + spinlock_t s_ext_stats_lock;
    + unsigned long s_ext_blocks;
    + unsigned long s_ext_extents;
    +#endif
    };

    #endif /* _LINUX_EXT4_FS_SB */
    diff -puN include/linux/ext4_jbd2.h~ext4-extents include/linux/ext4_jbd2.h
    --- linux-2.6.18-rc4/include/linux/ext4_jbd2.h~ext4-extents 2006-08-09 15:41:44.292227297 -0700
    +++ linux-2.6.18-rc4-ming/include/linux/ext4_jbd2.h 2006-08-09 15:41:44.321227532 -0700
    @@ -26,9 +26,14 @@
    *
    * We may have to touch one inode, one bitmap buffer, up to three
    * indirection blocks, the group and superblock summaries, and the data
    - * block to complete the transaction. */
    + * block to complete the transaction.
    + *
    + * For extents-enabled fs we may have to allocate and modify upto
    + * 5 levels of tree + root which is stored in inode. */

    -#define EXT4_SINGLEDATA_TRANS_BLOCKS 8U
    +#define EXT4_SINGLEDATA_TRANS_BLOCKS(sb) \
    + (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS) \
    + || test_opt(sb, EXTENTS) ? 27U : 8U)

    /* Extended attribute operations touch at most two data buffers,
    * two bitmap buffers, and two group summaries, in addition to the inode
    @@ -42,7 +47,7 @@
    * superblock only gets updated once, of course, so don't bother
    * counting that again for the quota updates. */

    -#define EXT4_DATA_TRANS_BLOCKS(sb) (EXT4_SINGLEDATA_TRANS_BLOCKS + \
    +#define EXT4_DATA_TRANS_BLOCKS(sb) (EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + \
    EXT4_XATTR_TRANS_BLOCKS - 2 + \
    2*EXT4_QUOTA_TRANS_BLOCKS(sb))

    @@ -78,9 +83,9 @@
    /* Amount of blocks needed for quota insert/delete - we do some block writes
    * but inode, sb and group updates are done only once */
    #define EXT4_QUOTA_INIT_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_INIT_ALLOC*\
    - (EXT4_SINGLEDATA_TRANS_BLOCKS-3)+3+DQUOT_INIT_REWRITE) : 0)
    + (EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)+3+DQUOT_INIT_REWRITE) : 0)
    #define EXT4_QUOTA_DEL_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_DEL_ALLOC*\
    - (EXT4_SINGLEDATA_TRANS_BLOCKS-3)+3+DQUOT_DEL_REWRITE) : 0)
    + (EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)+3+DQUOT_DEL_REWRITE) : 0)
    #else
    #define EXT4_QUOTA_TRANS_BLOCKS(sb) 0
    #define EXT4_QUOTA_INIT_BLOCKS(sb) 0
    _


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