1 files changed, 527 insertions, 0 deletions

diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
new file mode 100644
index 0000000..cbc8510
--- /dev/null
+++ b/fs/hfs/extent.c
@@ -0,0 +1,527 @@
+/*
+ *  linux/fs/hfs/extent.c
+ *
+ * Copyright (C) 1995-1997  Paul H. Hargrove
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ * This file may be distributed under the terms of the GNU General Public License.
+ *
+ * This file contains the functions related to the extents B-tree.
+ */
+
+#include <linux/pagemap.h>
+
+#include "hfs_fs.h"
+#include "btree.h"
+
+/*================ File-local functions ================*/
+
+/*
+ * build_key
+ */
+static void hfs_ext_build_key(hfs_btree_key *key, u32 cnid, u16 block, u8 type)
+{
+	key->key_len = 7;
+	key->ext.FkType = type;
+	key->ext.FNum = cpu_to_be32(cnid);
+	key->ext.FABN = cpu_to_be16(block);
+}
+
+/*
+ * hfs_ext_compare()
+ *
+ * Description:
+ *   This is the comparison function used for the extents B-tree.  In
+ *   comparing extent B-tree entries, the file id is the most
+ *   significant field (compared as unsigned ints); the fork type is
+ *   the second most significant field (compared as unsigned chars);
+ *   and the allocation block number field is the least significant
+ *   (compared as unsigned ints).
+ * Input Variable(s):
+ *   struct hfs_ext_key *key1: pointer to the first key to compare
+ *   struct hfs_ext_key *key2: pointer to the second key to compare
+ * Output Variable(s):
+ *   NONE
+ * Returns:
+ *   int: negative if key1<key2, positive if key1>key2, and 0 if key1==key2
+ * Preconditions:
+ *   key1 and key2 point to "valid" (struct hfs_ext_key)s.
+ * Postconditions:
+ *   This function has no side-effects */
+int hfs_ext_keycmp(const btree_key *key1, const btree_key *key2)
+{
+	__be32 fnum1, fnum2;
+	__be16 block1, block2;
+
+	fnum1 = key1->ext.FNum;
+	fnum2 = key2->ext.FNum;
+	if (fnum1 != fnum2)
+		return be32_to_cpu(fnum1) < be32_to_cpu(fnum2) ? -1 : 1;
+	if (key1->ext.FkType != key2->ext.FkType)
+		return key1->ext.FkType < key2->ext.FkType ? -1 : 1;
+
+	block1 = key1->ext.FABN;
+	block2 = key2->ext.FABN;
+	if (block1 == block2)
+		return 0;
+	return be16_to_cpu(block1) < be16_to_cpu(block2) ? -1 : 1;
+}
+
+/*
+ * hfs_ext_find_block
+ *
+ * Find a block within an extent record
+ */
+static u16 hfs_ext_find_block(struct hfs_extent *ext, u16 off)
+{
+	int i;
+	u16 count;
+
+	for (i = 0; i < 3; ext++, i++) {
+		count = be16_to_cpu(ext->count);
+		if (off < count)
+			return be16_to_cpu(ext->block) + off;
+		off -= count;
+	}
+	/* panic? */
+	return 0;
+}
+
+static int hfs_ext_block_count(struct hfs_extent *ext)
+{
+	int i;
+	u16 count = 0;
+
+	for (i = 0; i < 3; ext++, i++)
+		count += be16_to_cpu(ext->count);
+	return count;
+}
+
+static u16 hfs_ext_lastblock(struct hfs_extent *ext)
+{
+	int i;
+
+	ext += 2;
+	for (i = 0; i < 2; ext--, i++)
+		if (ext->count)
+			break;
+	return be16_to_cpu(ext->block) + be16_to_cpu(ext->count);
+}
+
+static void __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
+{
+	int res;
+
+	hfs_ext_build_key(fd->search_key, inode->i_ino, HFS_I(inode)->cached_start,
+			  HFS_IS_RSRC(inode) ?  HFS_FK_RSRC : HFS_FK_DATA);
+	res = hfs_brec_find(fd);
+	if (HFS_I(inode)->flags & HFS_FLG_EXT_NEW) {
+		if (res != -ENOENT)
+			return;
+		hfs_brec_insert(fd, HFS_I(inode)->cached_extents, sizeof(hfs_extent_rec));
+		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
+	} else {
+		if (res)
+			return;
+		hfs_bnode_write(fd->bnode, HFS_I(inode)->cached_extents, fd->entryoffset, fd->entrylength);
+		HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY;
+	}
+}
+
+void hfs_ext_write_extent(struct inode *inode)
+{
+	struct hfs_find_data fd;
+
+	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
+		hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
+		__hfs_ext_write_extent(inode, &fd);
+		hfs_find_exit(&fd);
+	}
+}
+
+static inline int __hfs_ext_read_extent(struct hfs_find_data *fd, struct hfs_extent *extent,
+					u32 cnid, u32 block, u8 type)
+{
+	int res;
+
+	hfs_ext_build_key(fd->search_key, cnid, block, type);
+	fd->key->ext.FNum = 0;
+	res = hfs_brec_find(fd);
+	if (res && res != -ENOENT)
+		return res;
+	if (fd->key->ext.FNum != fd->search_key->ext.FNum ||
+	    fd->key->ext.FkType != fd->search_key->ext.FkType)
+		return -ENOENT;
+	if (fd->entrylength != sizeof(hfs_extent_rec))
+		return -EIO;
+	hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfs_extent_rec));
+	return 0;
+}
+
+static inline int __hfs_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
+{
+	int res;
+
+	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY)
+		__hfs_ext_write_extent(inode, fd);
+
+	res = __hfs_ext_read_extent(fd, HFS_I(inode)->cached_extents, inode->i_ino,
+				    block, HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA);
+	if (!res) {
+		HFS_I(inode)->cached_start = be16_to_cpu(fd->key->ext.FABN);
+		HFS_I(inode)->cached_blocks = hfs_ext_block_count(HFS_I(inode)->cached_extents);
+	} else {
+		HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0;
+		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
+	}
+	return res;
+}
+
+static int hfs_ext_read_extent(struct inode *inode, u16 block)
+{
+	struct hfs_find_data fd;
+	int res;
+
+	if (block >= HFS_I(inode)->cached_start &&
+	    block < HFS_I(inode)->cached_start + HFS_I(inode)->cached_blocks)
+		return 0;
+
+	hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
+	res = __hfs_ext_cache_extent(&fd, inode, block);
+	hfs_find_exit(&fd);
+	return res;
+}
+
+static void hfs_dump_extent(struct hfs_extent *extent)
+{
+	int i;
+
+	dprint(DBG_EXTENT, "   ");
+	for (i = 0; i < 3; i++)
+		dprint(DBG_EXTENT, " %u:%u", be16_to_cpu(extent[i].block),
+				 be16_to_cpu(extent[i].count));
+	dprint(DBG_EXTENT, "\n");
+}
+
+static int hfs_add_extent(struct hfs_extent *extent, u16 offset,
+			  u16 alloc_block, u16 block_count)
+{
+	u16 count, start;
+	int i;
+
+	hfs_dump_extent(extent);
+	for (i = 0; i < 3; extent++, i++) {
+		count = be16_to_cpu(extent->count);
+		if (offset == count) {
+			start = be16_to_cpu(extent->block);
+			if (alloc_block != start + count) {
+				if (++i >= 3)
+					return -ENOSPC;
+				extent++;
+				extent->block = cpu_to_be16(alloc_block);
+			} else
+				block_count += count;
+			extent->count = cpu_to_be16(block_count);
+			return 0;
+		} else if (offset < count)
+			break;
+		offset -= count;
+	}
+	/* panic? */
+	return -EIO;
+}
+
+static int hfs_free_extents(struct super_block *sb, struct hfs_extent *extent,
+			    u16 offset, u16 block_nr)
+{
+	u16 count, start;
+	int i;
+
+	hfs_dump_extent(extent);
+	for (i = 0; i < 3; extent++, i++) {
+		count = be16_to_cpu(extent->count);
+		if (offset == count)
+			goto found;
+		else if (offset < count)
+			break;
+		offset -= count;
+	}
+	/* panic? */
+	return -EIO;
+found:
+	for (;;) {
+		start = be16_to_cpu(extent->block);
+		if (count <= block_nr) {
+			hfs_clear_vbm_bits(sb, start, count);
+			extent->block = 0;
+			extent->count = 0;
+			block_nr -= count;
+		} else {
+			count -= block_nr;
+			hfs_clear_vbm_bits(sb, start + count, block_nr);
+			extent->count = cpu_to_be16(count);
+			block_nr = 0;
+		}
+		if (!block_nr || !i)
+			return 0;
+		i--;
+		extent--;
+		count = be16_to_cpu(extent->count);
+	}
+}
+
+int hfs_free_fork(struct super_block *sb, struct hfs_cat_file *file, int type)
+{
+	struct hfs_find_data fd;
+	u32 total_blocks, blocks, start;
+	u32 cnid = be32_to_cpu(file->FlNum);
+	struct hfs_extent *extent;
+	int res, i;
+
+	if (type == HFS_FK_DATA) {
+		total_blocks = be32_to_cpu(file->PyLen);
+		extent = file->ExtRec;
+	} else {
+		total_blocks = be32_to_cpu(file->RPyLen);
+		extent = file->RExtRec;
+	}
+	total_blocks /= HFS_SB(sb)->alloc_blksz;
+	if (!total_blocks)
+		return 0;
+
+	blocks = 0;
+	for (i = 0; i < 3; extent++, i++)
+		blocks += be16_to_cpu(extent[i].count);
+
+	res = hfs_free_extents(sb, extent, blocks, blocks);
+	if (res)
+		return res;
+	if (total_blocks == blocks)
+		return 0;
+
+	hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+	do {
+		res = __hfs_ext_read_extent(&fd, extent, cnid, total_blocks, type);
+		if (res)
+			break;
+		start = be16_to_cpu(fd.key->ext.FABN);
+		hfs_free_extents(sb, extent, total_blocks - start, total_blocks);
+		hfs_brec_remove(&fd);
+		total_blocks = start;
+	} while (total_blocks > blocks);
+	hfs_find_exit(&fd);
+
+	return res;
+}
+
+/*
+ * hfs_get_block
+ */
+int hfs_get_block(struct inode *inode, sector_t block,
+		  struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb;
+	u16 dblock, ablock;
+	int res;
+
+	sb = inode->i_sb;
+	/* Convert inode block to disk allocation block */
+	ablock = (u32)block / HFS_SB(sb)->fs_div;
+
+	if (block >= HFS_I(inode)->fs_blocks) {
+		if (block > HFS_I(inode)->fs_blocks || !create)
+			return -EIO;
+		if (ablock >= HFS_I(inode)->alloc_blocks) {
+			res = hfs_extend_file(inode);
+			if (res)
+				return res;
+		}
+	} else
+		create = 0;
+
+	if (ablock < HFS_I(inode)->first_blocks) {
+		dblock = hfs_ext_find_block(HFS_I(inode)->first_extents, ablock);
+		goto done;
+	}
+
+	down(&HFS_I(inode)->extents_lock);
+	res = hfs_ext_read_extent(inode, ablock);
+	if (!res)
+		dblock = hfs_ext_find_block(HFS_I(inode)->cached_extents,
+					    ablock - HFS_I(inode)->cached_start);
+	else {
+		up(&HFS_I(inode)->extents_lock);
+		return -EIO;
+	}
+	up(&HFS_I(inode)->extents_lock);
+
+done:
+	map_bh(bh_result, sb, HFS_SB(sb)->fs_start +
+	       dblock * HFS_SB(sb)->fs_div +
+	       (u32)block % HFS_SB(sb)->fs_div);
+
+	if (create) {
+		set_buffer_new(bh_result);
+		HFS_I(inode)->phys_size += sb->s_blocksize;
+		HFS_I(inode)->fs_blocks++;
+		inode_add_bytes(inode, sb->s_blocksize);
+		mark_inode_dirty(inode);
+	}
+	return 0;
+}
+
+int hfs_extend_file(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	u32 start, len, goal;
+	int res;
+
+	down(&HFS_I(inode)->extents_lock);
+	if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks)
+		goal = hfs_ext_lastblock(HFS_I(inode)->first_extents);
+	else {
+		res = hfs_ext_read_extent(inode, HFS_I(inode)->alloc_blocks);
+		if (res)
+			goto out;
+		goal = hfs_ext_lastblock(HFS_I(inode)->cached_extents);
+	}
+
+	len = HFS_I(inode)->clump_blocks;
+	start = hfs_vbm_search_free(sb, goal, &len);
+	if (!len) {
+		res = -ENOSPC;
+		goto out;
+	}
+
+	dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
+	if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks) {
+		if (!HFS_I(inode)->first_blocks) {
+			dprint(DBG_EXTENT, "first extents\n");
+			/* no extents yet */
+			HFS_I(inode)->first_extents[0].block = cpu_to_be16(start);
+			HFS_I(inode)->first_extents[0].count = cpu_to_be16(len);
+			res = 0;
+		} else {
+			/* try to append to extents in inode */
+			res = hfs_add_extent(HFS_I(inode)->first_extents,
+					     HFS_I(inode)->alloc_blocks,
+					     start, len);
+			if (res == -ENOSPC)
+				goto insert_extent;
+		}
+		if (!res) {
+			hfs_dump_extent(HFS_I(inode)->first_extents);
+			HFS_I(inode)->first_blocks += len;
+		}
+	} else {
+		res = hfs_add_extent(HFS_I(inode)->cached_extents,
+				     HFS_I(inode)->alloc_blocks -
+				     HFS_I(inode)->cached_start,
+				     start, len);
+		if (!res) {
+			hfs_dump_extent(HFS_I(inode)->cached_extents);
+			HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY;
+			HFS_I(inode)->cached_blocks += len;
+		} else if (res == -ENOSPC)
+			goto insert_extent;
+	}
+out:
+	up(&HFS_I(inode)->extents_lock);
+	if (!res) {
+		HFS_I(inode)->alloc_blocks += len;
+		mark_inode_dirty(inode);
+		if (inode->i_ino < HFS_FIRSTUSER_CNID)
+			set_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags);
+		set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
+		sb->s_dirt = 1;
+	}
+	return res;
+
+insert_extent:
+	dprint(DBG_EXTENT, "insert new extent\n");
+	hfs_ext_write_extent(inode);
+
+	memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
+	HFS_I(inode)->cached_extents[0].block = cpu_to_be16(start);
+	HFS_I(inode)->cached_extents[0].count = cpu_to_be16(len);
+	hfs_dump_extent(HFS_I(inode)->cached_extents);
+	HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW;
+	HFS_I(inode)->cached_start = HFS_I(inode)->alloc_blocks;
+	HFS_I(inode)->cached_blocks = len;
+
+	res = 0;
+	goto out;
+}
+
+void hfs_file_truncate(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfs_find_data fd;
+	u16 blk_cnt, alloc_cnt, start;
+	u32 size;
+	int res;
+
+	dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
+	       (long long)HFS_I(inode)->phys_size, inode->i_size);
+	if (inode->i_size > HFS_I(inode)->phys_size) {
+		struct address_space *mapping = inode->i_mapping;
+		struct page *page;
+		int res;
+
+		size = inode->i_size - 1;
+		page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
+		if (!page)
+			return;
+		size &= PAGE_CACHE_SIZE - 1;
+		size++;
+		res = mapping->a_ops->prepare_write(NULL, page, size, size);
+		if (!res)
+			res = mapping->a_ops->commit_write(NULL, page, size, size);
+		if (res)
+			inode->i_size = HFS_I(inode)->phys_size;
+		unlock_page(page);
+		page_cache_release(page);
+		mark_inode_dirty(inode);
+		return;
+	}
+	size = inode->i_size + HFS_SB(sb)->alloc_blksz - 1;
+	blk_cnt = size / HFS_SB(sb)->alloc_blksz;
+	alloc_cnt = HFS_I(inode)->alloc_blocks;
+	if (blk_cnt == alloc_cnt)
+		goto out;
+
+	down(&HFS_I(inode)->extents_lock);
+	hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+	while (1) {
+		if (alloc_cnt == HFS_I(inode)->first_blocks) {
+			hfs_free_extents(sb, HFS_I(inode)->first_extents,
+					 alloc_cnt, alloc_cnt - blk_cnt);
+			hfs_dump_extent(HFS_I(inode)->first_extents);
+			HFS_I(inode)->first_blocks = blk_cnt;
+			break;
+		}
+		res = __hfs_ext_cache_extent(&fd, inode, alloc_cnt);
+		if (res)
+			break;
+		start = HFS_I(inode)->cached_start;
+		hfs_free_extents(sb, HFS_I(inode)->cached_extents,
+				 alloc_cnt - start, alloc_cnt - blk_cnt);
+		hfs_dump_extent(HFS_I(inode)->cached_extents);
+		if (blk_cnt > start) {
+			HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY;
+			break;
+		}
+		alloc_cnt = start;
+		HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0;
+		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
+		hfs_brec_remove(&fd);
+	}
+	hfs_find_exit(&fd);
+	up(&HFS_I(inode)->extents_lock);
+
+	HFS_I(inode)->alloc_blocks = blk_cnt;
+out:
+	HFS_I(inode)->phys_size = inode->i_size;
+	HFS_I(inode)->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+	inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
+	mark_inode_dirty(inode);
+}