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SubjectRe: [RFC] extents support for EXT3
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Date
>>>>> Ed Sweetman (ES) writes:

ES> This patch seems to be against test2, just wondering if anyone before
ES> me has used it on the latest test release. If not then i'm gonna do
ES> something stupid and be the first.

I would be happy to see anyone trying this patch ;)

following patch applies to -test4 ok


fs/ext3/Makefile | 2
fs/ext3/extents.c | 1567 +++++++++++++++++++++++++++++++++++++++++++++
fs/ext3/ialloc.c | 2
fs/ext3/inode.c | 25
fs/ext3/super.c | 11
include/linux/ext3_fs.h | 17
include/linux/ext3_fs_i.h | 4
include/linux/ext3_fs_sb.h | 10
8 files changed, 1632 insertions(+), 6 deletions(-)

diff -puN /dev/null fs/ext3/extents.c
--- /dev/null 2003-01-30 13:24:37.000000000 +0300
+++ linux-2.6.0-test4-alexey/fs/ext3/extents.c 2003-08-29 09:58:39.000000000 +0400
@@ -0,0 +1,1567 @@
+/*
+ *
+ * linux/fs/ext3/extents.c
+ *
+ * Extents support for EXT3
+ *
+ * 07/08/2003 Alex Tomas <bzzz@tmi.comex.ru>
+ *
+ * TODO:
+ * - ext3*_error() should be used in some situations
+ * - find_goal() [to be tested and improved]
+ * - quick search for index/leaf in ext3_ext_find_extent()
+ * - tree reduction
+ * - cache last found extent
+ * - arch-independent
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/ext3_jbd.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/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/mpage.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_
+
+/*
+ * if EXT_DEBUG 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(inode,fmt,a...) \
+do { \
+ if (test_opt((inode)->i_sb, EXTDEBUG)) \
+ printk(fmt, ##a); \
+} while (0);
+#else
+#define ext_debug(inode,fmt,a...)
+#endif
+
+#define EXT3_ALLOC_NEEDED 2 /* block bitmap + group descriptor */
+
+/*
+ * ext3_inode has i_block array (total 60 bytes)
+ * first 4 bytes are used to store:
+ * - tree depth (0 mean there is no tree yet. all extents in the inode)
+ * - number of alive extents in the inode
+ */
+
+/*
+ * this is extent on-disk structure
+ * it's used at the bottom of the tree
+ */
+struct ext3_extent {
+ __u32 e_block; /* first logical block extent covers */
+ __u32 e_start; /* first physical block extents lives */
+ __u32 e_num; /* number of blocks covered by extent */
+};
+
+/*
+ * this is index on-disk structure
+ * it's used at all the levels, but the bottom
+ */
+struct ext3_extent_idx {
+ __u32 e_block; /* index covers logical blocks from 'block' */
+ __u32 e_leaf; /* pointer to the physical block of the next *
+ * level. leaf or next index could bet here */
+};
+
+/*
+ * each block (leaves and indexes), even inode-stored has header
+ */
+struct ext3_extent_header {
+ __u16 e_num; /* number of valid entries */
+ __u16 e_max; /* capacity of store in entries */
+};
+
+/*
+ * array of ext3_ext_path contains path to some extent
+ * creation/lookup routines use it for traversal/splitting/etc
+ * truncate uses it to simulate recursive walking
+ */
+struct ext3_ext_path {
+ __u32 p_block;
+ __u16 p_depth;
+ struct ext3_extent *p_ext;
+ struct ext3_extent_idx *p_idx;
+ struct ext3_extent_header *p_hdr;
+ struct buffer_head *p_bh;
+};
+
+#define EXT_FIRST_EXTENT(__hdr__) \
+ ((struct ext3_extent *) (((char *) (__hdr__)) + \
+ sizeof(struct ext3_extent_header)))
+#define EXT_FIRST_INDEX(__hdr__) \
+ ((struct ext3_extent_idx *) (((char *) (__hdr__)) + \
+ sizeof(struct ext3_extent_header)))
+#define EXT_HAS_FREE_INDEX(__path__) \
+ ((__path__)->p_hdr->e_num < (__path__)->p_hdr->e_max)
+#define EXT_LAST_EXTENT(__hdr__) \
+ (EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->e_num - 1)
+#define EXT_LAST_INDEX(__hdr__) \
+ (EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->e_num - 1)
+#define EXT_MAX_EXTENT(__hdr__) \
+ (EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->e_max - 1)
+#define EXT_MAX_INDEX(__hdr__) \
+ (EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->e_max - 1)
+
+
+#define EXT_ASSERT(__x__) if (!(__x__)) BUG();
+
+/*
+ * could return:
+ * - EROFS
+ * - ENOMEM
+ */
+static int ext3_ext_get_access(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ if (path->p_bh) {
+ /* path points to block */
+ return ext3_journal_get_write_access(handle, path->p_bh);
+ }
+
+ /* path points to leaf/index in inode body */
+ return 0;
+}
+
+/*
+ * could return:
+ * - EROFS
+ * - ENOMEM
+ * - EIO
+ */
+static int ext3_ext_dirty(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ if (path->p_bh) {
+ /* path points to block */
+ return ext3_journal_dirty_metadata(handle, path->p_bh);
+ }
+
+ /* path points to leaf/index in inode body */
+ return ext3_mark_inode_dirty(handle, inode);
+}
+
+static inline int ext3_ext_space_block(struct inode *inode)
+{
+ int size;
+
+ size = (inode->i_sb->s_blocksize - sizeof(struct ext3_extent_header))
+ / sizeof(struct ext3_extent);
+#ifdef AGRESSIVE_TEST
+ size = 6; /* FIXME: for debug, remove this line */
+#endif
+ return size;
+}
+
+static inline int ext3_ext_space_inode(struct inode *inode)
+{
+ int size;
+
+ size = (sizeof(EXT3_I(inode)->i_data) -
+ sizeof(struct ext3_extent_header))
+ / sizeof(struct ext3_extent);
+#ifdef AGRESSIVE_TEST
+ size = 3; /* FIXME: for debug, remove this line */
+#endif
+ return size;
+}
+
+static inline int ext3_ext_space_inode_idx(struct inode *inode)
+{
+ int size;
+
+ size = (sizeof(EXT3_I(inode)->i_data) -
+ sizeof(struct ext3_extent_header))
+ / sizeof(struct ext3_extent_idx);
+#ifdef AGRESSIVE_TEST
+ size = 4; /* FIXME: for debug, remove this line */
+#endif
+ return size;
+}
+
+static void ext3_ext_show_path(struct inode *inode, struct ext3_ext_path *path)
+{
+ int k, l = path->p_depth;
+
+ ext_debug(inode, "path:");
+ for (k = 0; k <= l; k++, path++) {
+ if (path->p_idx) {
+ ext_debug(inode, " %d->%d", path->p_idx->e_block,
+ path->p_idx->e_leaf);
+ } else if (path->p_ext) {
+ ext_debug(inode, " %d:%d:%d",
+ path->p_ext->e_block,
+ path->p_ext->e_start,
+ path->p_ext->e_num);
+ } else
+ ext_debug(inode, " []");
+ }
+ ext_debug(inode, "\n");
+}
+
+static void ext3_ext_show_leaf(struct inode *inode, struct ext3_ext_path *path)
+{
+ int depth = EXT3_I(inode)->i_depth;
+ struct ext3_extent_header *eh = path[depth].p_hdr;
+ struct ext3_extent *ex = EXT_FIRST_EXTENT(eh);
+ int i;
+
+ for (i = 0; i < eh->e_num; i++, ex++) {
+ ext_debug(inode, "%d:%d:%d ",
+ ex->e_block, ex->e_start, ex->e_num);
+ }
+ ext_debug(inode, "\n");
+}
+
+static void ext3_ext_drop_refs(struct inode *inode, struct ext3_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;
+ }
+}
+
+static int ext3_ext_find_goal(struct inode *inode, struct ext3_ext_path *path)
+{
+ struct ext3_inode_info *ei = EXT3_I(inode);
+ unsigned long bg_start;
+ unsigned long colour;
+ int depth;
+
+ if (path) {
+ depth = path->p_depth;
+ /* try to find previous block */
+ if (path[depth].p_ext)
+ return path[depth].p_ext->e_start +
+ path[depth].p_ext->e_num - 1;
+
+ /* 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 * EXT3_BLOCKS_PER_GROUP(inode->i_sb)) +
+ le32_to_cpu(EXT3_SB(inode->i_sb)->s_es->s_first_data_block);
+ colour = (current->pid % 16) *
+ (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+ return bg_start + colour;
+}
+
+static struct ext3_ext_path *
+ext3_ext_find_extent(struct inode *inode, int block, struct ext3_ext_path *path)
+{
+ struct ext3_inode_info *ei = EXT3_I(inode);
+ struct ext3_extent_header *eh = (void *) ei->i_data;
+ struct ext3_extent_idx *ix;
+ struct buffer_head *bh;
+ struct ext3_extent *ex;
+ int depth, i, k, ppos = 0;
+
+ eh = (struct ext3_extent_header *) ei->i_data;
+
+ /* initialize capacity of leaf in inode for first time */
+ if (eh->e_max == 0)
+ eh->e_max = ext3_ext_space_inode(inode);
+ i = depth = ei->i_depth;
+ EXT_ASSERT(i == 0 || eh->e_num > 0);
+
+ /* account possible depth increase */
+ if (!path) {
+ path = kmalloc(sizeof(struct ext3_ext_path) * (depth + 2),
+ GFP_NOFS);
+ if (!path)
+ return ERR_PTR(-ENOMEM);
+ }
+ memset(path, 0, sizeof(struct ext3_ext_path) * (depth + 1));
+
+ /* walk through the tree */
+ while (i) {
+ ext_debug(inode, "depth %d: num %d, max %d\n",
+ ppos, eh->e_num, eh->e_max);
+ ix = EXT_FIRST_INDEX(eh);
+ if (eh->e_num)
+ path[ppos].p_idx = ix;
+ EXT_ASSERT(eh->e_num <= eh->e_max);
+ for (k = 0; k < eh->e_num; k++, ix++) {
+ ext_debug(inode, "index: %d -> %d\n",
+ ix->e_block, ix->e_leaf);
+ if (block < ix->e_block)
+ break;
+ path[ppos].p_idx = ix;
+ }
+ path[ppos].p_block = path[ppos].p_idx->e_leaf;
+ path[ppos].p_depth = i;
+ path[ppos].p_hdr = eh;
+ path[ppos].p_ext = NULL;
+
+ bh = sb_bread(inode->i_sb, path[ppos].p_block);
+ if (!bh) {
+ ext3_ext_drop_refs(inode, path);
+ kfree(path);
+ return ERR_PTR(-EIO);
+ }
+ eh = (struct ext3_extent_header *) bh->b_data;
+ ppos++;
+ EXT_ASSERT(ppos <= depth);
+ path[ppos].p_bh = bh;
+ i--;
+ }
+
+ path[ppos].p_depth = i;
+ path[ppos].p_hdr = eh;
+ path[ppos].p_ext = NULL;
+
+ /* find extent */
+ ex = EXT_FIRST_EXTENT(eh);
+ if (eh->e_num)
+ path[ppos].p_ext = ex;
+ EXT_ASSERT(eh->e_num <= eh->e_max);
+ for (k = 0; k < eh->e_num; k++, ex++) {
+ if (block < ex->e_block)
+ break;
+ path[ppos].p_ext = ex;
+ }
+
+ ext3_ext_show_path(inode, path);
+
+ return path;
+}
+
+static void ext3_ext_check_boundary(struct inode *inode,
+ struct ext3_ext_path *curp,
+ void *addr, int len)
+{
+ void *end;
+
+ if (!len)
+ return;
+ if (curp->p_bh)
+ end = (void *) curp->p_hdr + inode->i_sb->s_blocksize;
+ else
+ end = (void *) curp->p_hdr + sizeof(EXT3_I(inode)->i_data);
+ if (((unsigned long) addr) + len > (unsigned long) end) {
+ printk("overflow! 0x%p > 0x%p\n", addr + len, end);
+ BUG();
+ }
+ if ((unsigned long) addr < (unsigned long) curp->p_hdr) {
+ printk("underflow! 0x%p < 0x%p\n", addr, curp->p_hdr);
+ BUG();
+ }
+}
+
+/*
+ * insert new index [logical;ptr] into the block at cupr
+ * it check where to insert: before curp or after curp
+ */
+static int ext3_ext_insert_index(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *curp, int logical,
+ int ptr)
+{
+ struct ext3_extent_idx *ix;
+ int len, err;
+
+ if ((err = ext3_ext_get_access(handle, inode, curp)))
+ return err;
+
+ EXT_ASSERT(logical != curp->p_idx->e_block);
+ len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
+ if (logical > curp->p_idx->e_block) {
+ /* insert after */
+ len = (len - 1) * sizeof(struct ext3_extent_idx);
+ len = len < 0 ? 0 : len;
+ ext_debug(inode, "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));
+
+ ext3_ext_check_boundary(inode, curp, curp->p_idx + 2, len);
+ memmove(curp->p_idx + 2, curp->p_idx + 1, len);
+ ix = curp->p_idx + 1;
+ } else {
+ /* insert before */
+ len = len * sizeof(struct ext3_extent_idx);
+ len = len < 0 ? 0 : len;
+ ext_debug(inode, "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));
+
+ ext3_ext_check_boundary(inode, curp, curp->p_idx + 1, len);
+ memmove(curp->p_idx + 1, curp->p_idx, len);
+ ix = curp->p_idx;
+ }
+
+ ix->e_block = logical;
+ ix->e_leaf = ptr;
+ curp->p_hdr->e_num++;
+
+ err = ext3_ext_dirty(handle, inode, curp);
+ ext3_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 ext3_ext_split(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path,
+ struct ext3_extent *newext, int at)
+{
+ struct buffer_head *bh = NULL;
+ int depth = EXT3_I(inode)->i_depth;
+ struct ext3_extent_header *neh;
+ struct ext3_extent_idx *fidx;
+ struct ext3_extent *ex;
+ int i = at, k, m, a;
+ sector_t newblock, oldblock, 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 */
+ if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
+ border = path[depth].p_ext[1].e_block;
+ ext_debug(inode, "leaf will be splitted."
+ " next leaf starts at %d\n",
+ (int)border);
+ } else {
+ border = newext->e_block;
+ ext_debug(inode, "leaf will be added."
+ " next leaf starts at %d\n",
+ (int)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(sector_t) * depth, GFP_NOFS);
+ if (!ablocks)
+ return -ENOMEM;
+ memset(ablocks, 0, sizeof(sector_t) * depth);
+
+ /* allocate all needed blocks */
+ ext_debug(inode, "allocate %d blocks for indexes and leaf\n",
+ depth - at);
+ ablocks[0] = newext->e_start++;
+ newext->e_num--;
+ for (a = 1; a < depth - at; a++) {
+ newblock = ext3_new_block(handle, inode, newext->e_start,
+ 0, 0, &err);
+ if (newblock == 0)
+ goto cleanup;
+ ablocks[a] = newblock;
+ }
+
+ /* initialize new leaf */
+ newblock = ablocks[--a];
+ EXT_ASSERT(newblock);
+ bh = sb_getblk(inode->i_sb, newblock);
+ if (!bh) {
+ err = -EIO;
+ goto cleanup;
+ }
+ lock_buffer(bh);
+
+ if ((err = ext3_journal_get_create_access(handle, bh)))
+ goto cleanup;
+
+ neh = (struct ext3_extent_header *) bh->b_data;
+ neh->e_num = 0;
+ neh->e_max = ext3_ext_space_block(inode);
+ ex = EXT_FIRST_EXTENT(neh);
+
+ /* move remain of path[depth] to the new leaf */
+ EXT_ASSERT(path[depth].p_hdr->e_num ==
+ path[depth].p_hdr->e_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(inode, "move %d:%d:%d in new leaf\n",
+ path[depth].p_ext->e_block,
+ path[depth].p_ext->e_start,
+ path[depth].p_ext->e_num);
+ memmove(ex++, path[depth].p_ext++,
+ sizeof(struct ext3_extent));
+ neh->e_num++;
+ m++;
+ }
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+
+ if ((err = ext3_journal_dirty_metadata(handle, bh)))
+ goto cleanup;
+ brelse(bh);
+ bh = NULL;
+
+ /* correct old leaf */
+ if (m) {
+ if ((err = ext3_ext_get_access(handle, inode, path)))
+ goto cleanup;
+ path[depth].p_hdr->e_num -= m;
+ if ((err = ext3_ext_dirty(handle, inode, path)))
+ goto cleanup;
+
+ }
+
+ /* create intermediate indexes */
+ k = depth - at - 1;
+ EXT_ASSERT(k >= 0);
+ if (k)
+ ext_debug(inode,
+ "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 = ext3_journal_get_create_access(handle, bh)))
+ goto cleanup;
+
+ neh = (struct ext3_extent_header *) bh->b_data;
+ neh->e_num = 1;
+ neh->e_max = ext3_ext_space_block(inode);
+ fidx = EXT_FIRST_INDEX(neh);
+ fidx->e_block = border;
+ fidx->e_leaf = oldblock;
+
+ ext_debug(inode,
+ "int.index at %d (block %u): %d -> %d\n",
+ i, (unsigned) newblock,
+ (int) border,
+ (int) oldblock);
+ /* copy indexes */
+ m = 0;
+ path[i].p_idx++;
+ EXT_ASSERT(EXT_MAX_INDEX(path[i].p_hdr) ==
+ EXT_LAST_INDEX(path[i].p_hdr));
+ ext_debug(inode, "cur 0x%p, last 0x%p\n", path[i].p_idx,
+ EXT_MAX_INDEX(path[i].p_hdr));
+ while (path[i].p_idx <=
+ EXT_MAX_INDEX(path[i].p_hdr)) {
+ ext_debug(inode, "%d: move %d:%d in new index\n",
+ i, path[i].p_idx->e_block,
+ path[i].p_idx->e_leaf);
+ memmove(++fidx, path[i].p_idx++,
+ sizeof(struct ext3_extent_idx));
+ neh->e_num++;
+ m++;
+ }
+
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+
+ if ((err = ext3_journal_dirty_metadata(handle, bh)))
+ goto cleanup;
+ brelse(bh);
+ bh = NULL;
+
+ /* correct old index */
+ if (m) {
+ err = ext3_ext_get_access(handle,inode,path+i);
+ if (err)
+ goto cleanup;
+ path[i].p_hdr->e_num -= m;
+ err = ext3_ext_dirty(handle, inode, path + i);
+ if (err)
+ goto cleanup;
+ }
+
+ i--;
+ }
+
+ /* insert new index */
+ if (!err)
+ err = ext3_ext_insert_index(handle, inode, path + at,
+ 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;
+ ext3_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 ext3_ext_grow_indepth(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path,
+ struct ext3_extent *newext)
+{
+ struct buffer_head *bh;
+ struct ext3_ext_path *curp = path;
+ struct ext3_extent_header *neh;
+ struct ext3_extent_idx *fidx;
+ int len, err = 0;
+ sector_t newblock;
+
+ /*
+ * use already allocated by the called block for new root block
+ */
+ newblock = newext->e_start++;
+ newext->e_num--;
+
+ bh = sb_getblk(inode->i_sb, newblock);
+ if (!bh) {
+ err = -EIO;
+ ext3_std_error(inode->i_sb, err);
+ return err;
+ }
+ lock_buffer(bh);
+
+ if ((err = ext3_journal_get_create_access(handle, bh))) {
+ unlock_buffer(bh);
+ goto out;
+ }
+
+ /* move top-level index/leaf into new block */
+ len = sizeof(struct ext3_extent_header) +
+ sizeof(struct ext3_extent) * curp->p_hdr->e_max;
+ EXT_ASSERT(len >= 0 && len < 4096);
+ memmove(bh->b_data, curp->p_hdr, len);
+
+ /* set size of new block */
+ neh = (struct ext3_extent_header *) bh->b_data;
+ neh->e_max = ext3_ext_space_block(inode);
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+
+ if ((err = ext3_journal_dirty_metadata(handle, bh)))
+ goto out;
+
+ /* create index in new top-level index: num,max,pointer */
+ if ((err = ext3_ext_get_access(handle, inode, curp)))
+ goto out;
+
+ curp->p_hdr->e_max = ext3_ext_space_inode_idx(inode);
+ curp->p_hdr->e_num = 1;
+ curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
+ curp->p_idx->e_block = EXT_FIRST_EXTENT(path[0].p_hdr)->e_block;
+ curp->p_idx->e_leaf = newblock;
+
+ neh = (struct ext3_extent_header *) EXT3_I(inode)->i_data;
+ fidx = EXT_FIRST_INDEX(neh);
+ ext_debug(inode, "new root: num %d(%d), lblock %d, ptr %d\n",
+ neh->e_num, neh->e_max, fidx->e_block, fidx->e_leaf);
+
+ EXT3_I(inode)->i_depth++;
+ err = ext3_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 ext3_ext_create_new_leaf(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path,
+ struct ext3_extent *newext)
+{
+ int depth = EXT3_I(inode)->i_depth;
+ struct ext3_ext_path *curp;
+ int i = depth, err = 0;
+ sector_t newblock = newext->e_start;
+
+ /* 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 = ext3_ext_split(handle, inode, path, newext, i);
+ } else {
+ /* tree is full, time to grow in depth */
+ err = ext3_ext_grow_indepth(handle, inode, path, newext);
+ }
+
+ if (!err) {
+ /* refill path */
+ ext3_ext_drop_refs(inode, path);
+ path = ext3_ext_find_extent(inode, newext->e_block, path);
+ if (IS_ERR(path))
+ err = PTR_ERR(path);
+
+ /*
+ * probably we've used some blocks from extent
+ * let's allocate new block for it
+ */
+ if (newext->e_num == 0 && !err) {
+ newext->e_start =
+ ext3_new_block(handle, inode, newblock,
+ 0, 0, &err);
+ newext->e_num = 1;
+ }
+ }
+
+ return err;
+}
+
+/*
+ * returns next allocated block or 0xffffffff
+ * NOTE: it consider block number from index entry as
+ * allocated block. thus, index entries have to be consistent
+ * with leafs
+ */
+static inline unsigned ext3_ext_next_allocated_block(struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ int depth;
+
+ EXT_ASSERT(path != NULL);
+ depth = path->p_depth;
+
+ if (depth == 0 && path->p_ext == NULL)
+ return 0xffffffff;
+
+ /* FIXME: what if index isn't full ?! */
+ while (depth >= 0) {
+ if (depth == path->p_depth) {
+ /* leaf */
+ if (path[depth].p_ext !=
+ EXT_LAST_EXTENT(path[depth].p_hdr))
+ return path[depth].p_ext[1].e_block;
+ } else {
+ /* index */
+ if (path[depth].p_idx !=
+ EXT_LAST_INDEX(path[depth].p_hdr))
+ return path[depth].p_idx[1].e_block;
+ }
+ depth--;
+ }
+
+ return 0xffffffff;
+}
+
+/*
+ * returns first allocated block from next leaf or 0xffffffff
+ */
+static unsigned ext3_ext_next_leaf_block(struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ int depth;
+
+ EXT_ASSERT(path != NULL);
+ depth = path->p_depth;
+
+ /* zero-tree has no leaf blocks at all */
+ if (depth == 0)
+ return 0xffffffff;
+
+ /* go to index block */
+ depth--;
+
+ while (depth >= 0) {
+ if (path[depth].p_idx !=
+ EXT_LAST_INDEX(path[depth].p_hdr))
+ return path[depth].p_idx[1].e_block;
+ depth--;
+ }
+
+ return 0xffffffff;
+}
+
+/*
+ * 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 ext3_ext_correct_indexes(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ int depth = EXT3_I(inode)->i_depth;
+ struct ext3_extent_header *eh;
+ struct ext3_extent *ex;
+ sector_t border;
+ int k, err = 0;
+
+ eh = path[depth].p_hdr;
+ ex = path[depth].p_ext;
+
+ EXT_ASSERT(ex);
+ EXT_ASSERT(eh);
+
+ 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;
+ }
+
+ k = depth - 1;
+ border = path[depth].p_ext->e_block;
+ if ((err = ext3_ext_get_access(handle, inode, path + k)))
+ return err;
+ path[k].p_idx->e_block = border;
+ if ((err = ext3_ext_dirty(handle, inode, path + k)))
+ return err;
+
+ while (k--) {
+ /* change all left-side indexes */
+ if (path[k].p_idx != EXT_FIRST_INDEX(path[k].p_hdr)
+ && k != 0)
+ break;
+ if ((err = ext3_ext_get_access(handle, inode, path + k)))
+ break;
+ path[k].p_idx->e_block = border;
+ if ((err = ext3_ext_dirty(handle, inode, path + k)))
+ break;
+ }
+
+ return err;
+}
+
+/*
+ * 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 ext3_ext_insert_extent(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path,
+ struct ext3_extent *newext)
+{
+ int depth, len;
+ struct ext3_extent_header * eh;
+ struct ext3_extent *ex;
+ struct ext3_extent *nearex; /* nearest extent */
+ struct ext3_ext_path *npath = NULL;
+ int err;
+
+ depth = EXT3_I(inode)->i_depth;
+ if ((ex = path[depth].p_ext)) {
+ /* try to insert block into found extent and return */
+ if (ex->e_block + ex->e_num == newext->e_block &&
+ ex->e_start + ex->e_num == newext->e_start) {
+#ifdef AGRESSIVE_TEST
+ if (ex->e_num >= 2)
+ goto repeat;
+#endif
+ if ((err = ext3_ext_get_access(handle, inode,
+ path + depth)))
+ return err;
+ ext_debug(inode, "append %d block to %d:%d (from %d)\n",
+ newext->e_num, ex->e_block, ex->e_num,
+ ex->e_start);
+ ex->e_num += newext->e_num;
+ err = ext3_ext_dirty(handle, inode, path + depth);
+ return err;
+ }
+ }
+
+repeat:
+ depth = EXT3_I(inode)->i_depth;
+ eh = path[depth].p_hdr;
+ if (eh->e_num == eh->e_max) {
+ /* probably next leaf has space for us? */
+ int next = ext3_ext_next_leaf_block(inode, path);
+ if (next != 0xffffffff) {
+ ext_debug(inode, "next leaf block - %d\n", next);
+ EXT_ASSERT(!npath);
+ npath = ext3_ext_find_extent(inode, next, NULL);
+ if (IS_ERR(npath))
+ return PTR_ERR(npath);
+ EXT_ASSERT(npath->p_depth == path->p_depth);
+ eh = npath[depth].p_hdr;
+ if (eh->e_num < eh->e_max) {
+ ext_debug(inode,
+ "next leaf has free ext(%d)\n",
+ eh->e_num);
+ path = npath;
+ goto repeat;
+ }
+ ext_debug(inode, "next leaf hasno free space(%d,%d)\n",
+ eh->e_num, eh->e_max);
+ }
+ /*
+ * there is no free space in found leaf
+ * we're gonna add new leaf in the tree
+ */
+ err = ext3_ext_create_new_leaf(handle, inode, path, newext);
+ if (err)
+ goto cleanup;
+ goto repeat;
+ }
+
+ nearex = path[depth].p_ext;
+
+ if ((err = ext3_ext_get_access(handle, inode, path + depth)))
+ goto cleanup;
+
+ if (!nearex) {
+ /* there is no extent in this leaf, create first one */
+ ext_debug(inode, "first extent in the leaf: %d:%d:%d\n",
+ newext->e_block, newext->e_start,
+ newext->e_num);
+ eh->e_num++;
+ path[depth].p_ext = EXT_FIRST_EXTENT(eh);
+
+ } else if (newext->e_block > nearex->e_block) {
+ EXT_ASSERT(newext->e_block != nearex->e_block);
+ len = EXT_MAX_EXTENT(eh) - nearex;
+ len = (len - 1) * sizeof(struct ext3_extent);
+ len = len < 0 ? 0 : len;
+ ext_debug(inode, "insert %d:%d:%d after: nearest 0x%p, "
+ "move %d from 0x%p to 0x%p\n",
+ newext->e_block, newext->e_start, newext->e_num,
+ nearex, len, nearex + 1, nearex + 2);
+ ext3_ext_check_boundary(inode, path + depth, nearex + 2, len);
+ memmove(nearex + 2, nearex + 1, len);
+ path[depth].p_ext = nearex + 1;
+ eh->e_num++;
+ } else {
+ EXT_ASSERT(newext->e_block != nearex->e_block);
+ len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext3_extent);
+ len = len < 0 ? 0 : len;
+ ext_debug(inode, "insert %d:%d:%d before: nearest 0x%p, "
+ "move %d from 0x%p to 0x%p\n",
+ newext->e_block, newext->e_start, newext->e_num,
+ nearex, len, nearex + 1, nearex + 2);
+ memmove(nearex + 1, nearex, len);
+ path[depth].p_ext = nearex;
+ eh->e_num++;
+
+ /* time to correct all indexes above */
+ err = ext3_ext_correct_indexes(handle, inode, path);
+ }
+
+ if (!err) {
+ nearex = path[depth].p_ext;
+ nearex->e_block = newext->e_block;
+ nearex->e_start = newext->e_start;
+ nearex->e_num = newext->e_num;
+ }
+
+ err = ext3_ext_dirty(handle, inode, path + depth);
+
+cleanup:
+ if (npath) {
+ ext3_ext_drop_refs(inode, npath);
+ kfree(npath);
+ }
+
+ return err;
+}
+
+int ext3_ext_get_block(handle_t *handle, struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create,
+ int extend_disksize)
+{
+ struct ext3_ext_path *path;
+ int depth = EXT3_I(inode)->i_depth;
+ struct ext3_extent newex;
+ struct ext3_extent *ex;
+ int goal, newblock, err = 0;
+
+ ext_debug(inode, "block %d requested for inode %u, bh_result 0x%p\n",
+ (int) iblock, (unsigned) inode->i_ino, bh_result);
+ clear_buffer_new(bh_result);
+
+ down(&EXT3_I(inode)->i_ext_sem);
+
+ /* find extent for this block */
+ path = ext3_ext_find_extent(inode, iblock, NULL);
+ if (IS_ERR(path)) {
+ err = PTR_ERR(path);
+ goto out2;
+ }
+
+ if ((ex = path[depth].p_ext)) {
+ /* if found exent covers block, simple return it */
+ if (iblock >= ex->e_block && iblock < ex->e_block + ex->e_num) {
+ newblock = iblock - ex->e_block + ex->e_start;
+ ext_debug(inode, "%d fit into %d:%d -> %d\n",
+ (int) iblock, ex->e_block, ex->e_num,
+ newblock);
+ goto out;
+ }
+ }
+
+ /*
+ * we couldn't try to create block if create flag is zero
+ */
+ if (!create)
+ goto out2;
+
+ /* allocate new block */
+ goal = ext3_ext_find_goal(inode, path);
+ newblock = ext3_new_block(handle, inode, goal, 0, 0, &err);
+ if (!newblock)
+ goto out2;
+ ext_debug(inode, "allocate new block: goal %d, found %d\n",
+ goal, newblock);
+
+ /* try to insert new extent into found leaf and return */
+ newex.e_block = iblock;
+ newex.e_start = newblock;
+ newex.e_num = 1;
+ err = ext3_ext_insert_extent(handle, inode, path, &newex);
+ if (err)
+ goto out2;
+
+ /* previous routine could use block we allocated */
+ newblock = newex.e_start;
+ set_buffer_new(bh_result);
+
+out:
+ ext3_ext_show_leaf(inode, path);
+ map_bh(bh_result, inode->i_sb, newblock);
+out2:
+ ext3_ext_drop_refs(inode, path);
+ kfree(path);
+ up(&EXT3_I(inode)->i_ext_sem);
+
+ return err;
+}
+
+/*
+ * returns 1 if current index have to be freed (even partial)
+ */
+static int ext3_ext_more_to_truncate(struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ EXT_ASSERT(path->p_idx);
+
+ 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 (path->p_hdr->e_num == path->p_block)
+ return 0;
+
+ /*
+ * put actual number of indexes to know is this number got
+ * changed at the next iteration
+ */
+ path->p_block = path->p_hdr->e_num;
+
+ return 1;
+}
+
+/*
+ * 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 ext3_ext_remove_index(handle_t *handle, struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ struct buffer_head *bh;
+ int err;
+
+ /* free index block */
+ path--;
+ EXT_ASSERT(path->p_hdr->e_num);
+ if ((err = ext3_ext_get_access(handle, inode, path)))
+ return err;
+ path->p_hdr->e_num--;
+ if ((err = ext3_ext_dirty(handle, inode, path)))
+ return err;
+ bh = sb_find_get_block(inode->i_sb, path->p_idx->e_leaf);
+ ext3_forget(handle, 0, inode, bh, path->p_idx->e_leaf);
+ ext3_free_blocks(handle, inode, path->p_idx->e_leaf, 1);
+
+ ext_debug(inode, "index is empty, remove it, free block %d\n",
+ path->p_idx->e_leaf);
+ return err;
+}
+
+/*
+ * returns 1 if current extent needs to be freed (even partial)
+ * instead, returns 0
+ */
+int ext3_ext_more_leaves_to_truncate(struct inode *inode,
+ struct ext3_ext_path *path)
+{
+ unsigned blocksize = inode->i_sb->s_blocksize;
+ struct ext3_extent *ex = path->p_ext;
+ int last_block;
+
+ EXT_ASSERT(ex);
+
+ /* is there leave in the current leaf? */
+ if (ex < EXT_FIRST_EXTENT(path->p_hdr))
+ return 0;
+
+ last_block = (inode->i_size + blocksize-1)
+ >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
+
+ if (last_block >= ex->e_block + ex->e_num)
+ return 0;
+
+ /* seems it extent have to be freed */
+ return 1;
+}
+
+handle_t *ext3_ext_journal_restart(handle_t *handle, int needed)
+{
+ int err;
+
+ if (handle->h_buffer_credits > needed)
+ return handle;
+ if (!ext3_journal_extend(handle, needed))
+ return handle;
+ err = ext3_journal_restart(handle, needed);
+
+ return handle;
+}
+
+/*
+ * this routine calculate max number of blocks to be modified
+ * while freeing extent and is intended to be used in truncate path
+ */
+static int ext3_ext_calc_credits(struct inode *inode,
+ struct ext3_ext_path *path,
+ int num)
+{
+ int depth = EXT3_I(inode)->i_depth;
+ int needed;
+
+ /*
+ * extent couldn't cross group, so we will modify
+ * single bitmap block and single group descriptor
+ */
+ needed = 2;
+
+ /*
+ * if this is last extent in a leaf, then we have to
+ * free leaf block and remove pointer from index above.
+ * that pointer could be last in index block, so we'll
+ * have to remove it too. this way we could modify/free
+ * the whole path + root index (inode stored) will be
+ * modified
+ */
+ if (!path || (num == path->p_ext->e_num &&
+ path->p_ext == EXT_FIRST_EXTENT(path->p_hdr)))
+ needed += (depth * EXT3_ALLOC_NEEDED) + 1;
+
+ return needed;
+}
+
+/*
+ * core of the truncate procedure:
+ * - calculated what part of each extent in the requested leaf
+ * need to be freed
+ * - frees and forgets these blocks
+ *
+ * TODO: we could optimize and free several extents during
+ * single journal_restart()-journal_restart() cycle
+ */
+static int ext3_ext_truncate_leaf(handle_t *handle,
+ struct inode *inode,
+ struct ext3_ext_path *path,
+ int depth)
+{
+ unsigned blocksize = inode->i_sb->s_blocksize;
+ int last_block;
+ int i, err = 0, sf, num;
+
+ ext_debug(inode, "level %d - leaf\n", depth);
+ if (!path->p_hdr)
+ path->p_hdr =
+ (struct ext3_extent_header *) path->p_bh->b_data;
+
+ EXT_ASSERT(path->p_hdr->e_num <= path->p_hdr->e_max);
+
+ last_block = (inode->i_size + blocksize-1)
+ >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
+ path->p_ext = EXT_LAST_EXTENT(path->p_hdr);
+ while (ext3_ext_more_leaves_to_truncate(inode, path)) {
+
+ /* what part of extent have to be freed? */
+ sf = last_block > path->p_ext->e_block ?
+ last_block : path->p_ext->e_block;
+
+ /* number of blocks from extent to be freed */
+ num = path->p_ext->e_block + path->p_ext->e_num - sf;
+
+ /* calc physical first physical block to be freed */
+ sf = path->p_ext->e_start + (sf - path->p_ext->e_block);
+
+ i = ext3_ext_calc_credits(inode, path, num);
+ handle = ext3_ext_journal_restart(handle, i);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ ext_debug(inode, "free extent %d:%d:%d -> free %d:%d\n",
+ path->p_ext->e_block, path->p_ext->e_start,
+ path->p_ext->e_num, sf, num);
+ for (i = 0; i < num; i++) {
+ struct buffer_head *bh =
+ sb_find_get_block(inode->i_sb, sf + i);
+ ext3_forget(handle, 0, inode, bh, sf + i);
+ }
+ ext3_free_blocks(handle, inode, sf, num);
+
+ /* collect extents usage stats */
+ spin_lock(&EXT3_SB(inode->i_sb)->s_ext_lock);
+ EXT3_SB(inode->i_sb)->s_ext_extents++;
+ EXT3_SB(inode->i_sb)->s_ext_blocks += num;
+ spin_unlock(&EXT3_SB(inode->i_sb)->s_ext_lock);
+
+ /* reduce extent */
+ if ((err = ext3_ext_get_access(handle, inode, path)))
+ return err;
+ path->p_ext->e_num -= num;
+ if (path->p_ext->e_num == 0)
+ path->p_hdr->e_num--;
+ if ((err = ext3_ext_dirty(handle, inode, path)))
+ return err;
+
+ path->p_ext--;
+ }
+
+ /* if this leaf is free, then we should
+ * remove it from index block above */
+ if (path->p_hdr->e_num == 0 && depth > 0)
+ err = ext3_ext_remove_index(handle, inode, path);
+
+ return err;
+}
+
+static void ext3_ext_collect_stats(struct inode *inode)
+{
+ int depth;
+
+ /* skip inodes with old good bitmap */
+ if (!(EXT3_I(inode)->i_flags & EXT3_EXTENTS_FL))
+ return;
+
+ /* collect on full truncate only */
+ if (inode->i_size)
+ return;
+
+ depth = EXT3_I(inode)->i_depth;
+ if (depth < EXT3_SB(inode->i_sb)->s_ext_mindepth)
+ EXT3_SB(inode->i_sb)->s_ext_mindepth = depth;
+ if (depth > EXT3_SB(inode->i_sb)->s_ext_maxdepth)
+ EXT3_SB(inode->i_sb)->s_ext_maxdepth = depth;
+ EXT3_SB(inode->i_sb)->s_ext_sum += depth;
+ EXT3_SB(inode->i_sb)->s_ext_count++;
+
+}
+
+void ext3_ext_truncate(struct inode * inode)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct ext3_ext_path *path;
+ struct page * page;
+ handle_t *handle;
+ int i, depth, err = 0;
+
+ ext3_ext_collect_stats(inode);
+
+ /*
+ * We have to lock the EOF page here, because lock_page() nests
+ * outside journal_start().
+ */
+ if ((inode->i_size & (inode->i_sb->s_blocksize - 1)) == 0) {
+ /* Block boundary? Nothing to do */
+ page = NULL;
+ } else {
+ page = grab_cache_page(mapping,
+ inode->i_size >> PAGE_CACHE_SHIFT);
+ if (!page)
+ return;
+ }
+
+ /*
+ * probably first extent we're gonna free will be last in block
+ */
+ i = ext3_ext_calc_credits(inode, NULL, 0);
+ handle = ext3_journal_start(inode, i);
+ if (IS_ERR(handle)) {
+ if (page) {
+ clear_highpage(page);
+ flush_dcache_page(page);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ return;
+ }
+
+ if (page)
+ ext3_block_truncate_page(handle, page, mapping, inode->i_size);
+
+ down(&EXT3_I(inode)->i_ext_sem);
+ /*
+ * TODO: optimization is possible here
+ * probably we need not scaning at all,
+ * because page truncation is enough
+ */
+ if (ext3_orphan_add(handle, inode))
+ goto out_stop;
+
+ /* we have to know where to truncate from in crash case */
+ EXT3_I(inode)->i_disksize = inode->i_size;
+ ext3_mark_inode_dirty(handle, inode);
+
+ /*
+ * we start scanning from right side freeing all the blocks
+ * after i_size and walking into the deep
+ */
+ i = 0;
+ depth = EXT3_I(inode)->i_depth;
+ path = kmalloc(sizeof(struct ext3_ext_path) * (depth + 1), GFP_KERNEL);
+ if (IS_ERR(path)) {
+ ext3_error(inode->i_sb, "ext3_ext_truncate",
+ "Can't allocate path array");
+ goto out_stop;
+ }
+ memset(path, 0, sizeof(struct ext3_ext_path) * (depth + 1));
+
+ path[i].p_hdr = (struct ext3_extent_header *) EXT3_I(inode)->i_data;
+ while (i >= 0 && err == 0) {
+ if (i == depth) {
+ /* this is leaf block */
+ err = ext3_ext_truncate_leaf(handle, inode,
+ path + i, i);
+ /* root level have p_bh == NULL, brelse() eats this */
+ brelse(path[i].p_bh);
+ i--;
+ continue;
+ }
+
+ /* this is index block */
+ if (!path[i].p_hdr) {
+ path[i].p_hdr =
+ (struct ext3_extent_header *) path[i].p_bh->b_data;
+ ext_debug(inode, "initialize header\n");
+ }
+
+ EXT_ASSERT(path[i].p_hdr->e_num <= path[i].p_hdr->e_max);
+
+ 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 = path[i].p_hdr->e_num + 1;
+ ext_debug(inode, "init index ptr: hdr 0x%p, num %d\n",
+ path[i].p_hdr, path[i].p_hdr->e_num);
+ } else {
+ /* we've already was here, see at next index */
+ path[i].p_idx--;
+ }
+
+ ext_debug(inode, "level %d - index, first 0x%p, cur 0x%p\n",
+ i, EXT_FIRST_INDEX(path[i].p_hdr),
+ path[i].p_idx);
+ if (ext3_ext_more_to_truncate(inode, path + i)) {
+ /* go to the next level */
+ ext_debug(inode, "move to level %d (block %d)\n", i+1,
+ path[i].p_idx->e_leaf);
+ memset(path + i + 1, 0, sizeof(*path));
+ path[i+1].p_bh = sb_bread(inode->i_sb,
+ path[i].p_idx->e_leaf);
+ if (!path[i+1].p_bh) {
+ /* should we reset i_size? */
+ err = -EIO;
+ break;
+ }
+ i++;
+ } else {
+ /* we finish processing this index, go up */
+ if (path[i].p_hdr->e_num == 0 && i > 0) {
+ /* index is empty, remove it
+ * handle must be already prepared by the
+ * truncate_leaf()
+ */
+ err = ext3_ext_remove_index(handle, inode,
+ path + i);
+ }
+ /* root level have p_bh == NULL, brelse() eats this */
+ brelse(path[i].p_bh);
+ i--;
+ ext_debug(inode, "return to level %d\n", i);
+ }
+ }
+
+ /* TODO: flexible tree reduction should be here */
+ if (path->p_hdr->e_num == 0) {
+ /*
+ * truncate to zero freed all the tree
+ * so, we need to correct i_depth
+ */
+ EXT3_I(inode)->i_depth = 0;
+ path->p_hdr->e_max = 0;
+ ext3_mark_inode_dirty(handle, inode);
+ }
+
+ kfree(path);
+
+ /* 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
+ * ext3_delete_inode(), and we allow that function to clean up the
+ * orphan info for us.
+ */
+ if (inode->i_nlink)
+ ext3_orphan_del(handle, inode);
+
+ up(&EXT3_I(inode)->i_ext_sem);
+ ext3_journal_stop(handle);
+}
+
+/*
+ * this routine calculate max number of blocks we could modify
+ * in order to allocate new block for an inode
+ */
+int ext3_ext_writepage_trans_blocks(struct inode *inode, int num)
+{
+ struct ext3_inode_info *ei = EXT3_I(inode);
+ int depth = ei->i_depth + 1;
+ int needed;
+
+ /*
+ * the worste case we're expecting is creation of the
+ * new root (growing in depth) with index splitting
+ * for splitting we have to consider depth + 1 because
+ * previous growing could increase it
+ */
+
+ /*
+ * growing in depth:
+ * block allocation + new root + old root
+ */
+ needed = EXT3_ALLOC_NEEDED + 2;
+
+ /* index split. we may need:
+ * allocate intermediate indexes and new leaf
+ * change two blocks at each level, but root
+ * modify root block (inode)
+ */
+ needed += (depth * EXT3_ALLOC_NEEDED) + (2 * depth) + 1;
+
+ /* caller want to allocate num blocks */
+ needed *= num;
+
+#ifdef CONFIG_QUOTA
+ /*
+ * FIXME: real calculation should be here
+ * it depends on blockmap format of qouta file
+ */
+ needed += 2 * EXT3_SINGLEDATA_TRANS_BLOCKS;
+#endif
+
+ return needed;
+}
+
+/*
+ * called at mount time
+ */
+void ext3_ext_init(struct super_block *sb)
+{
+ /*
+ * possible initialization would be here
+ */
+
+ if (test_opt(sb, EXTENTS))
+ printk("EXT3-fs: file extents enabled\n");
+ spin_lock_init(&EXT3_SB(sb)->s_ext_lock);
+}
+
+/*
+ * called at umount time
+ */
+void ext3_ext_release(struct super_block *sb)
+{
+ struct ext3_sb_info *sbi = EXT3_SB(sb);
+
+ /* show collected stats */
+ if (sbi->s_ext_count && sbi->s_ext_extents)
+ printk("EXT3-fs: min depth - %d, max depth - %d, "
+ "ave. depth - %d, ave. blocks/extent - %d\n",
+ sbi->s_ext_mindepth,
+ sbi->s_ext_maxdepth,
+ sbi->s_ext_sum / sbi->s_ext_count,
+ sbi->s_ext_blocks / sbi->s_ext_extents);
+}
+
diff -puN fs/ext3/ialloc.c~ext3-extents fs/ext3/ialloc.c
--- linux-2.6.0-test4/fs/ext3/ialloc.c~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/fs/ext3/ialloc.c 2003-08-29 09:58:39.000000000 +0400
@@ -600,6 +600,8 @@ got:
DQUOT_FREE_INODE(inode);
goto fail2;
}
+ if (test_opt(sb, EXTENTS))
+ EXT3_I(inode)->i_flags |= EXT3_EXTENTS_FL;
err = ext3_mark_inode_dirty(handle, inode);
if (err) {
ext3_std_error(sb, err);
diff -puN fs/ext3/inode.c~ext3-extents fs/ext3/inode.c
--- linux-2.6.0-test4/fs/ext3/inode.c~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/fs/ext3/inode.c 2003-08-29 09:58:39.000000000 +0400
@@ -862,6 +862,15 @@ changed:
goto reread;
}

+static inline int
+ext3_get_block_wrap(handle_t *handle, struct inode *inode, sector_t block,
+ struct buffer_head *bh, int create, int extend_disksize)
+{
+ if (EXT3_I(inode)->i_flags & EXT3_EXTENTS_FL)
+ return ext3_ext_get_block(handle, inode, block, bh, create, 1);
+ return ext3_get_block_handle(handle, inode, block, bh, create, 1);
+}
+
static int ext3_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
@@ -872,7 +881,7 @@ static int ext3_get_block(struct inode *
handle = ext3_journal_current_handle();
J_ASSERT(handle != 0);
}
- ret = ext3_get_block_handle(handle, inode, iblock,
+ ret = ext3_get_block_wrap(handle, inode, iblock,
bh_result, create, 1);
return ret;
}
@@ -899,7 +908,7 @@ ext3_direct_io_get_blocks(struct inode *
}
}
if (ret == 0)
- ret = ext3_get_block_handle(handle, inode, iblock,
+ ret = ext3_get_block_wrap(handle, inode, iblock,
bh_result, create, 0);
if (ret == 0)
bh_result->b_size = (1 << inode->i_blkbits);
@@ -921,7 +930,7 @@ struct buffer_head *ext3_getblk(handle_t
dummy.b_state = 0;
dummy.b_blocknr = -1000;
buffer_trace_init(&dummy.b_history);
- *errp = ext3_get_block_handle(handle, inode, block, &dummy, create, 1);
+ *errp = ext3_get_block_wrap(handle, inode, block, &dummy, create, 1);
if (!*errp && buffer_mapped(&dummy)) {
struct buffer_head *bh;
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
@@ -1663,7 +1672,7 @@ void ext3_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 ext3_block_truncate_page(handle_t *handle, struct page *page,
+int ext3_block_truncate_page(handle_t *handle, struct page *page,
struct address_space *mapping, loff_t from)
{
unsigned long index = from >> PAGE_CACHE_SHIFT;
@@ -2145,6 +2154,9 @@ void ext3_truncate(struct inode * inode)

ext3_discard_prealloc(inode);

+ if (EXT3_I(inode)->i_flags & EXT3_EXTENTS_FL)
+ return ext3_ext_truncate(inode);
+
/*
* We have to lock the EOF page here, because lock_page() nests
* outside journal_start().
@@ -2540,6 +2552,7 @@ void ext3_read_inode(struct inode * inod
ei->i_prealloc_count = 0;
#endif
ei->i_block_group = iloc.block_group;
+ ei->i_depth = raw_inode->osd2.linux2.l_i_depth;

/*
* NOTE! The in-memory inode i_data array is in little-endian order
@@ -2636,6 +2649,7 @@ static int ext3_do_update_inode(handle_t
raw_inode->i_frag = ei->i_frag_no;
raw_inode->i_fsize = ei->i_frag_size;
#endif
+ raw_inode->osd2.linux2.l_i_depth = ei->i_depth;
raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
if (!S_ISREG(inode->i_mode)) {
raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
@@ -2840,6 +2854,9 @@ int ext3_writepage_trans_blocks(struct i
int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
int ret;

+ if (EXT3_I(inode)->i_flags & EXT3_EXTENTS_FL)
+ return ext3_ext_writepage_trans_blocks(inode, bpp);
+
if (ext3_should_journal_data(inode))
ret = 3 * (bpp + indirects) + 2;
else
diff -puN fs/ext3/Makefile~ext3-extents fs/ext3/Makefile
--- linux-2.6.0-test4/fs/ext3/Makefile~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/fs/ext3/Makefile 2003-08-29 09:58:39.000000000 +0400
@@ -5,7 +5,7 @@
obj-$(CONFIG_EXT3_FS) += ext3.o

ext3-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
+ ioctl.o namei.o super.o symlink.o hash.o extents.o

ext3-$(CONFIG_EXT3_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
ext3-$(CONFIG_EXT3_FS_POSIX_ACL) += acl.o
diff -puN fs/ext3/super.c~ext3-extents fs/ext3/super.c
--- linux-2.6.0-test4/fs/ext3/super.c~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/fs/ext3/super.c 2003-08-29 09:58:39.000000000 +0400
@@ -446,6 +446,7 @@ void ext3_put_super (struct super_block
struct ext3_super_block *es = sbi->s_es;
int i;

+ ext3_ext_release(sb);
ext3_xattr_put_super(sb);
journal_destroy(sbi->s_journal);
if (!(sb->s_flags & MS_RDONLY)) {
@@ -504,6 +505,8 @@ static struct inode *ext3_alloc_inode(st
ei->i_default_acl = EXT3_ACL_NOT_CACHED;
#endif
ei->vfs_inode.i_version = 1;
+ ei->i_depth = 0;
+ sema_init(&ei->i_ext_sem, 1);
return &ei->vfs_inode;
}

@@ -656,6 +659,12 @@ static int parse_options (char * options
continue;
if ((value = strchr (this_char, '=')) != NULL)
*value++ = 0;
+ if (!strcmp (this_char, "extents"))
+ set_opt (sbi->s_mount_opt, EXTENTS);
+ else
+ if (!strcmp (this_char, "extdebug"))
+ set_opt (sbi->s_mount_opt, EXTDEBUG);
+ else
#ifdef CONFIG_EXT3_FS_XATTR
if (!strcmp (this_char, "user_xattr"))
set_opt (sbi->s_mount_opt, XATTR_USER);
@@ -1442,6 +1451,8 @@ static int ext3_fill_super (struct super
percpu_counter_mod(&sbi->s_dirs_counter,
ext3_count_dirs(sb));

+ ext3_ext_init(sb);
+
return 0;

failed_mount3:
diff -puN include/linux/ext3_fs.h~ext3-extents include/linux/ext3_fs.h
--- linux-2.6.0-test4/include/linux/ext3_fs.h~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/include/linux/ext3_fs.h 2003-08-29 09:58:39.000000000 +0400
@@ -186,6 +186,7 @@ struct ext3_group_desc
#define EXT3_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */
#define EXT3_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/
#define EXT3_RESERVED_FL 0x80000000 /* reserved for ext3 lib */
+#define EXT3_EXTENTS_FL 0x00080000 /* Inode uses extents */

#define EXT3_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */
#define EXT3_FL_USER_MODIFIABLE 0x000380FF /* User modifiable flags */
@@ -244,7 +245,7 @@ struct ext3_inode {
struct {
__u8 l_i_frag; /* Fragment number */
__u8 l_i_fsize; /* Fragment size */
- __u16 i_pad1;
+ __u16 l_i_depth;
__u16 l_i_uid_high; /* these 2 fields */
__u16 l_i_gid_high; /* were reserved2[0] */
__u32 l_i_reserved2;
@@ -324,6 +325,8 @@ struct ext3_inode {
#define EXT3_MOUNT_NO_UID32 0x2000 /* Disable 32-bit UIDs */
#define EXT3_MOUNT_XATTR_USER 0x4000 /* Extended user attributes */
#define EXT3_MOUNT_POSIX_ACL 0x8000 /* POSIX Access Control Lists */
+#define EXT3_MOUNT_EXTENTS 0x10000 /* Extents support */
+#define EXT3_MOUNT_EXTDEBUG 0x20000 /* Extents debug */

/* Compatibility, for having both ext2_fs.h and ext3_fs.h included at once */
#ifndef _LINUX_EXT2_FS_H
@@ -733,6 +736,11 @@ extern int ext3_change_inode_journal_fla
extern void ext3_truncate (struct inode *);
extern void ext3_set_inode_flags(struct inode *);
extern void ext3_set_aops(struct inode *inode);
+extern int ext3_block_truncate_page(handle_t *handle, struct page *page,
+ struct address_space *mapping, loff_t from);
+extern int ext3_forget(handle_t *handle, int is_metadata,
+ struct inode *inode, struct buffer_head *bh,
+ int blocknr);

/* ioctl.c */
extern int ext3_ioctl (struct inode *, struct file *, unsigned int,
@@ -789,6 +797,13 @@ extern struct inode_operations ext3_spec
extern struct inode_operations ext3_symlink_inode_operations;
extern struct inode_operations ext3_fast_symlink_inode_operations;

+/* extents.c */
+extern int ext3_ext_writepage_trans_blocks(struct inode *, int);
+extern int ext3_ext_get_block(handle_t *, struct inode *, sector_t,
+ struct buffer_head *, int, int);
+extern void ext3_ext_truncate(struct inode *);
+extern void ext3_ext_init(struct super_block *);
+extern void ext3_ext_release(struct super_block *);

#endif /* __KERNEL__ */

diff -puN include/linux/ext3_fs_i.h~ext3-extents include/linux/ext3_fs_i.h
--- linux-2.6.0-test4/include/linux/ext3_fs_i.h~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/include/linux/ext3_fs_i.h 2003-08-29 09:58:39.000000000 +0400
@@ -108,6 +108,10 @@ struct ext3_inode_info {
*/
struct rw_semaphore truncate_sem;
struct inode vfs_inode;
+
+ /* extents-related data */
+ struct semaphore i_ext_sem;
+ __u16 i_depth;
};

#endif /* _LINUX_EXT3_FS_I */
diff -puN include/linux/ext3_fs_sb.h~ext3-extents include/linux/ext3_fs_sb.h
--- linux-2.6.0-test4/include/linux/ext3_fs_sb.h~ext3-extents 2003-08-29 09:58:39.000000000 +0400
+++ linux-2.6.0-test4-alexey/include/linux/ext3_fs_sb.h 2003-08-29 09:58:39.000000000 +0400
@@ -68,6 +68,16 @@ struct ext3_sb_info {
struct timer_list turn_ro_timer; /* For turning read-only (crash simulation) */
wait_queue_head_t ro_wait_queue; /* For people waiting for the fs to go read-only */
#endif
+
+ /* extents */
+ int s_ext_debug;
+ int s_ext_mindepth;
+ int s_ext_maxdepth;
+ int s_ext_sum;
+ int s_ext_count;
+ spinlock_t s_ext_lock;
+ int s_ext_extents;
+ int s_ext_blocks;
};

#endif /* _LINUX_EXT3_FS_SB */
_

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