--- /dev/null
+/*
+ * 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>
+
+
+/*
+ * ext_pblock:
+ * combine low and high parts of physical block number into ext4_fsblk_t
+ */
+static ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
+{
+ ext4_fsblk_t block;
+
+ block = le32_to_cpu(ex->ee_start);
+ block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
+ return block;
+}
+
+/*
+ * idx_pblock:
+ * combine low and high parts of a leaf physical block number into ext4_fsblk_t
+ */
+static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
+{
+ ext4_fsblk_t block;
+
+ block = le32_to_cpu(ix->ei_leaf);
+ block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
+ return block;
+}
+
+/*
+ * ext4_ext_store_pblock:
+ * stores a large physical block number into an extent struct,
+ * breaking it into parts
+ */
+static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
+{
+ ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+ ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
+}
+
+/*
+ * ext4_idx_store_pblock:
+ * stores a large physical block number into an index struct,
+ * breaking it into parts
+ */
+static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
+{
+ ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+ ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
+}
+
+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 ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
+ struct ext4_ext_path *path,
+ ext4_fsblk_t block)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ ext4_fsblk_t bg_start;
+ ext4_grpblk_t colour;
+ int depth;
+
+ if (path) {
+ struct ext4_extent *ex;
+ depth = path->p_depth;
+
+ /* try to predict block placement */
+ ex = path[depth].p_ext;
+ if (ex)
+ return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
+
+ /* it looks like index is empty;
+ * try to find starting block 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 ext4_fsblk_t
+ext4_ext_new_block(handle_t *handle, struct inode *inode,
+ struct ext4_ext_path *path,
+ struct ext4_extent *ex, int *err)
+{
+ ext4_fsblk_t 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 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 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 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 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->%llu", le32_to_cpu(path->p_idx->ei_block),
+ idx_pblock(path->p_idx));
+ } else if (path->p_ext) {
+ ext_debug(" %d:%d:%llu ",
+ le32_to_cpu(path->p_ext->ee_block),
+ le16_to_cpu(path->p_ext->ee_len),
+ ext_pblock(path->p_ext));
+ } 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:%llu ", le32_to_cpu(ex->ee_block),
+ le16_to_cpu(ex->ee_len), ext_pblock(ex));
+ }
+ 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;
+ }
+}
+
+/*
+ * ext4_ext_binsearch_idx:
+ * binary search for the closest index of the 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->%lld ", le32_to_cpu(path->p_idx->ei_block),
+ idx_block(path->p_idx));
+
+#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
+
+}
+
+/*
+ * ext4_ext_binsearch:
+ * binary search for closest extent of the 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:
+ * 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:%llu:%d ",
+ le32_to_cpu(path->p_ext->ee_block),
+ ext_pblock(path->p_ext),
+ 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 = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
+ GFP_NOFS);
+ if (!path)
+ return ERR_PTR(-ENOMEM);
+ alloc = 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 = idx_pblock(path[ppos].p_idx);
+ 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);
+}
+
+/*
+ * ext4_ext_insert_index:
+ * insert new index [@logical;@ptr] into the block at @curp;
+ * 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, ext4_fsblk_t ptr)
+{
+ struct ext4_extent_idx *ix;
+ int len, err;
+
+ err = ext4_ext_get_access(handle, inode, curp);
+ if (err)
+ 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);
+ ext4_idx_store_pblock(ix, 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;
+}
+
+/*
+ * ext4_ext_split:
+ * 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 extents and index entries (right to the split point)
+ * into the newly allocated blocks
+ * - initializes 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;
+ ext4_fsblk_t newblock, oldblock;
+ __le32 border;
+ ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
+ int err = 0;
+
+ /* make decision: where to split? */
+ /* FIXME: now decision is simplest: at current extent */
+
+ /* if current leaf will be split, 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 split."
+ " 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 mark filesystem read-only. 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 = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
+ if (!ablocks)
+ return -ENOMEM;
+
+ /* 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);
+
+ err = ext4_journal_get_create_access(handle, bh);
+ if (err)
+ 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 remainder 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:%llu:%d in new leaf %llu\n",
+ le32_to_cpu(path[depth].p_ext->ee_block),
+ ext_pblock(path[depth].p_ext),
+ 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);
+
+ err = ext4_journal_dirty_metadata(handle, bh);
+ if (err)
+ goto cleanup;
+ brelse(bh);
+ bh = NULL;
+
+ /* correct old leaf */
+ if (m) {
+ err = ext4_ext_get_access(handle, inode, path + depth);
+ if (err)
+ goto cleanup;
+ path[depth].p_hdr->eh_entries =
+ cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
+ err = ext4_ext_dirty(handle, inode, path + depth);
+ if (err)
+ 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, (ext4_fsblk_t)newblock);
+ if (!bh) {
+ err = -EIO;
+ goto cleanup;
+ }
+ lock_buffer(bh);
+
+ err = ext4_journal_get_create_access(handle, bh);
+ if (err)
+ 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;
+ ext4_idx_store_pblock(fidx, oldblock);
+
+ ext_debug("int.index at %d (block %llu): %lu -> %llu\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 %llu\n", i,
+ le32_to_cpu(path[i].p_idx->ei_block),
+ idx_pblock(path[i].p_idx),
+ 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);
+
+ err = ext4_journal_dirty_metadata(handle, bh);
+ if (err)
+ 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 */
+ 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;
+}
+
+/*
+ * ext4_ext_grow_indepth:
+ * implements tree growing procedure:
+ * - allocates new block
+ * - moves top-level data (index block or leaf) into the new block
+ * - initializes 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;
+ ext4_fsblk_t 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);
+
+ err = ext4_journal_get_create_access(handle, bh);
+ if (err) {
+ 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);
+
+ err = ext4_journal_dirty_metadata(handle, bh);
+ if (err)
+ goto out;
+
+ /* create index in new top-level index: num,max,pointer */
+ err = ext4_ext_get_access(handle, inode, curp);
+ if (err)
+ 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;
+ ext4_idx_store_pblock(curp->p_idx, newblock);
+
+ neh = ext_inode_hdr(inode);
+ fidx = EXT_FIRST_INDEX(neh);
+ ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
+ le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
+ le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
+
+ neh->eh_depth = cpu_to_le16(path->p_depth + 1);
+ err = ext4_ext_dirty(handle, inode, curp);
+out:
+ brelse(bh);
+
+ return err;
+}
+
+/*
+ * ext4_ext_create_new_leaf:
+ * finds empty index and adds new leaf.
+ * if no free index is 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 contiguous */
+ 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 the grown tree
+ */
+ depth = ext_depth(inode);
+ if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
+ /* now we need to split */
+ goto repeat;
+ }
+ }
+
+out:
+ return err;
+}
+
+/*
+ * ext4_ext_next_allocated_block:
+ * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
+ * NOTE: it considers block number from index entry as
+ * allocated block. Thus, index entries have to be consistent
+ * with leaves.
+ */
+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;
+}
+
+/*
+ * ext4_ext_next_leaf_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;
+}
+
+/*
+ * ext4_ext_correct_indexes:
+ * 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 than current one
+ */
+ k = depth - 1;
+ border = path[depth].p_ext->ee_block;
+ err = ext4_ext_get_access(handle, inode, path + k);
+ if (err)
+ return err;
+ path[k].p_idx->ei_block = border;
+ err = ext4_ext_dirty(handle, inode, path + k);
+ if (err)
+ return err;
+
+ while (k--) {
+ /* change all left-side indexes */
+ if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
+ break;
+ err = ext4_ext_get_access(handle, inode, path + k);
+ if (err)
+ break;
+ path[k].p_idx->ei_block = border;
+ err = ext4_ext_dirty(handle, inode, path + k);
+ if (err)
+ break;
+ }
+
+ return err;
+}
+
+static int
+ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
+ struct ext4_extent *ex2)
+{
+ if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) !=
+ le32_to_cpu(ex2->ee_block))
+ return 0;
+
+ /*
+ * To allow future support for preallocated extents to be added
+ * as an RO_COMPAT feature, refuse to merge to extents if
+ * this can result in the top bit of ee_len being set.
+ */
+ if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
+ return 0;
+#ifdef AGRESSIVE_TEST
+ if (le16_to_cpu(ex1->ee_len) >= 4)
+ return 0;
+#endif
+
+ if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
+ return 1;
+ return 0;
+}
+
+/*
+ * ext4_ext_insert_extent:
+ * tries to merge requsted extent into the existing extent or
+ * inserts requested extent as new one into the tree,
+ * creating new leaf in the 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 %llu)\n",
+ le16_to_cpu(newext->ee_len),
+ le32_to_cpu(ex->ee_block),
+ le16_to_cpu(ex->ee_len), ext_pblock(ex));
+ err = ext4_ext_get_access(handle, inode, path + depth);
+ if (err)
+ 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 the found leaf.
+ * We're gonna add a 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;
+
+ err = ext4_ext_get_access(handle, inode, path + depth);
+ if (err)
+ goto cleanup;
+
+ if (!nearex) {
+ /* there is no extent in this leaf, create first one */
+ ext_debug("first extent in the leaf: %d:%llu:%d\n",
+ le32_to_cpu(newext->ee_block),
+ ext_pblock(newext),
+ 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:%llu:%d after: nearest 0x%p, "
+ "move %d from 0x%p to 0x%p\n",
+ le32_to_cpu(newext->ee_block),
+ ext_pblock(newext),
+ 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:%llu:%d before: nearest 0x%p, "
+ "move %d from 0x%p to 0x%p\n",
+ le32_to_cpu(newext->ee_block),
+ ext_pblock(newext),
+ 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_start_hi = newext->ee_start_hi;
+ nearex->ee_len = newext->ee_len;
+
+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 = ext_pblock(ex);
+ 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 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;
+}
+
+/*
+ * ext4_ext_put_gap_in_cache:
+ * calculate boundaries of the gap that the requested block fits into
+ * and cache this gap
+ */
+static 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 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);
+ ext4_ext_store_pblock(ex, cex->ec_start);
+ ex->ee_len = cpu_to_le16(cex->ec_len);
+ ext_debug("%lu cached by %lu:%lu:%llu\n",
+ (unsigned long) block,
+ (unsigned long) cex->ec_block,
+ (unsigned long) cex->ec_len,
+ cex->ec_start);
+ return cex->ec_type;
+ }
+
+ /* not in cache */
+ return EXT4_EXT_CACHE_NO;
+}
+
+/*
+ * ext4_ext_rm_idx:
+ * 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;
+ ext4_fsblk_t leaf;
+
+ /* free index block */
+ path--;
+ leaf = idx_pblock(path->p_idx);
+ BUG_ON(path->p_hdr->eh_entries == 0);
+ err = ext4_ext_get_access(handle, inode, path);
+ if (err)
+ return err;
+ path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
+ err = ext4_ext_dirty(handle, inode, path);
+ if (err)
+ return err;
+ ext_debug("index is empty, remove it, free block %llu\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;
+}
+
+/*
+ * ext4_ext_calc_credits_for_insert:
+ * This routine returns max. credits that the extent tree can consume.
+ * It should be OK for low-performance paths like ->writepage()
+ * To allow many writing processes to fit into a single transaction,
+ * the caller should calculate credits under truncate_mutex and
+ * pass the actual path.
+ */
+int 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 32-bit 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 would need to grow in depth:
+ * we need one credit to modify old root, credits for
+ * new root will be added in split accounting
+ */
+ needed += 1;
+
+ /*
+ * Index split can happen, we would 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;
+ ext4_fsblk_t start;
+ num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
+ start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
+ ext_debug("free last %lu blocks starting %llu\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; mark slot entirely unused */
+ ext4_ext_store_pblock(ex, 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:%llu\n", block, num,
+ ext_pblock(ex));
+ 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;
+}
+
+/*
+ * ext4_ext_more_to_rm:
+ * returns 1 if current index has to be freed (even partial)
+ */
+static int
+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 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 tree depth-wise.
+ */
+ path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
+ if (path == NULL) {
+ ext4_journal_stop(handle);
+ return -ENOMEM;
+ }
+ 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 has 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 been 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 were already 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 %llu)\n",
+ i + 1, idx_pblock(path[i].p_idx));
+ memset(path + i + 1, 0, sizeof(*path));
+ path[i+1].p_bh =
+ sb_bread(sb, idx_pblock(path[i].p_idx));
+ if (!path[i+1].p_bh) {
+ /* should we reset i_size? */
+ err = -EIO;
+ break;
+ }
+
+ /* save actual number of indexes since this
+ * number is changed at the next iteration */
+ path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
+ i++;
+ } else {
+ /* we finished 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 has 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,
+ ext4_fsblk_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;
+ ext4_fsblk_t goal, newblock;
+ int 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 */
+ goal = ext4_ext_in_cache(inode, iblock, &newex);
+ if (goal) {
+ if (goal == EXT4_EXT_CACHE_GAP) {
+ if (!create) {
+ /* block isn't allocated yet and
+ * user doesn'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)
+ + ext_pblock(&newex);
+ /* number of remaining 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 situation 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);
+
+ ex = path[depth].p_ext;
+ if (ex) {
+ unsigned long ee_block = le32_to_cpu(ex->ee_block);
+ ext4_fsblk_t ee_start = ext_pblock(ex);
+ unsigned short ee_len = le16_to_cpu(ex->ee_len);
+
+ /*
+ * Allow future support for preallocated extents to be added
+ * as an RO_COMPAT feature:
+ * Uninitialized extents are treated as holes, except that
+ * we avoid (fail) allocating new blocks during a write.
+ */
+ if (ee_len > EXT_MAX_LEN)
+ goto out2;
+ /* if found extent covers block, simply return it */
+ if (iblock >= ee_block && iblock < ee_block + ee_len) {
+ newblock = iblock - ee_block + ee_start;
+ /* number of remaining blocks in the extent */
+ allocated = ee_len - (iblock - ee_block);
+ ext_debug("%d fit into %lu:%d -> %llu\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 speed up
+ * subsequent requests */
+ 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 %llu, found %llu/%lu\n",
+ goal, newblock, allocated);
+
+ /* try to insert new extent into found leaf and return */
+ newex.ee_block = cpu_to_le32(iblock);
+ ext4_ext_store_pblock(&newex, 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 = ext_pblock(&newex);
+ __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 scan 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);
+}
+
+/*
+ * ext4_ext_writepage_trans_blocks:
+ * 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 wants 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);
+
git://git.onelab.eu / linux-2.6.git / blobdiff