1 files changed, 583 insertions, 0 deletions

diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
new file mode 100644
index 00000000..5849e3ef
--- /dev/null
+++ b/fs/hfsplus/extents.c
@@ -0,0 +1,583 @@
+/*
+ *  linux/fs/hfsplus/extents.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Handling of Extents both in catalog and extents overflow trees
+ */
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+
+#include "hfsplus_fs.h"
+#include "hfsplus_raw.h"
+
+/* Compare two extents keys, returns 0 on same, pos/neg for difference */
+int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
+			const hfsplus_btree_key *k2)
+{
+	__be32 k1id, k2id;
+	__be32 k1s, k2s;
+
+	k1id = k1->ext.cnid;
+	k2id = k2->ext.cnid;
+	if (k1id != k2id)
+		return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
+
+	if (k1->ext.fork_type != k2->ext.fork_type)
+		return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
+
+	k1s = k1->ext.start_block;
+	k2s = k2->ext.start_block;
+	if (k1s == k2s)
+		return 0;
+	return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
+}
+
+static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
+				  u32 block, u8 type)
+{
+	key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
+	key->ext.cnid = cpu_to_be32(cnid);
+	key->ext.start_block = cpu_to_be32(block);
+	key->ext.fork_type = type;
+	key->ext.pad = 0;
+}
+
+static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
+{
+	int i;
+	u32 count;
+
+	for (i = 0; i < 8; ext++, i++) {
+		count = be32_to_cpu(ext->block_count);
+		if (off < count)
+			return be32_to_cpu(ext->start_block) + off;
+		off -= count;
+	}
+	/* panic? */
+	return 0;
+}
+
+static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
+{
+	int i;
+	u32 count = 0;
+
+	for (i = 0; i < 8; ext++, i++)
+		count += be32_to_cpu(ext->block_count);
+	return count;
+}
+
+static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
+{
+	int i;
+
+	ext += 7;
+	for (i = 0; i < 7; ext--, i++)
+		if (ext->block_count)
+			break;
+	return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
+}
+
+static void __hfsplus_ext_write_extent(struct inode *inode,
+		struct hfs_find_data *fd)
+{
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	int res;
+
+	WARN_ON(!mutex_is_locked(&hip->extents_lock));
+
+	hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
+			      HFSPLUS_IS_RSRC(inode) ?
+				HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
+
+	res = hfs_brec_find(fd);
+	if (hip->extent_state & HFSPLUS_EXT_NEW) {
+		if (res != -ENOENT)
+			return;
+		hfs_brec_insert(fd, hip->cached_extents,
+				sizeof(hfsplus_extent_rec));
+		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
+	} else {
+		if (res)
+			return;
+		hfs_bnode_write(fd->bnode, hip->cached_extents,
+				fd->entryoffset, fd->entrylength);
+		hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
+	}
+
+	/*
+	 * We can't just use hfsplus_mark_inode_dirty here, because we
+	 * also get called from hfsplus_write_inode, which should not
+	 * redirty the inode.  Instead the callers have to be careful
+	 * to explicily mark the inode dirty, too.
+	 */
+	set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
+}
+
+static int hfsplus_ext_write_extent_locked(struct inode *inode)
+{
+	int res;
+
+	if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
+		struct hfs_find_data fd;
+
+		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
+		if (res)
+			return res;
+		__hfsplus_ext_write_extent(inode, &fd);
+		hfs_find_exit(&fd);
+	}
+	return 0;
+}
+
+int hfsplus_ext_write_extent(struct inode *inode)
+{
+	int res;
+
+	mutex_lock(&HFSPLUS_I(inode)->extents_lock);
+	res = hfsplus_ext_write_extent_locked(inode);
+	mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
+
+	return res;
+}
+
+static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
+					    struct hfsplus_extent *extent,
+					    u32 cnid, u32 block, u8 type)
+{
+	int res;
+
+	hfsplus_ext_build_key(fd->search_key, cnid, block, type);
+	fd->key->ext.cnid = 0;
+	res = hfs_brec_find(fd);
+	if (res && res != -ENOENT)
+		return res;
+	if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
+	    fd->key->ext.fork_type != fd->search_key->ext.fork_type)
+		return -ENOENT;
+	if (fd->entrylength != sizeof(hfsplus_extent_rec))
+		return -EIO;
+	hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
+		sizeof(hfsplus_extent_rec));
+	return 0;
+}
+
+static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
+		struct inode *inode, u32 block)
+{
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	int res;
+
+	WARN_ON(!mutex_is_locked(&hip->extents_lock));
+
+	if (hip->extent_state & HFSPLUS_EXT_DIRTY)
+		__hfsplus_ext_write_extent(inode, fd);
+
+	res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
+					block, HFSPLUS_IS_RSRC(inode) ?
+						HFSPLUS_TYPE_RSRC :
+						HFSPLUS_TYPE_DATA);
+	if (!res) {
+		hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
+		hip->cached_blocks =
+			hfsplus_ext_block_count(hip->cached_extents);
+	} else {
+		hip->cached_start = hip->cached_blocks = 0;
+		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
+	}
+	return res;
+}
+
+static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
+{
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	struct hfs_find_data fd;
+	int res;
+
+	if (block >= hip->cached_start &&
+	    block < hip->cached_start + hip->cached_blocks)
+		return 0;
+
+	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
+	if (!res) {
+		res = __hfsplus_ext_cache_extent(&fd, inode, block);
+		hfs_find_exit(&fd);
+	}
+	return res;
+}
+
+/* Get a block at iblock for inode, possibly allocating if create */
+int hfsplus_get_block(struct inode *inode, sector_t iblock,
+		      struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	int res = -EIO;
+	u32 ablock, dblock, mask;
+	sector_t sector;
+	int was_dirty = 0;
+	int shift;
+
+	/* Convert inode block to disk allocation block */
+	shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
+	ablock = iblock >> sbi->fs_shift;
+
+	if (iblock >= hip->fs_blocks) {
+		if (iblock > hip->fs_blocks || !create)
+			return -EIO;
+		if (ablock >= hip->alloc_blocks) {
+			res = hfsplus_file_extend(inode);
+			if (res)
+				return res;
+		}
+	} else
+		create = 0;
+
+	if (ablock < hip->first_blocks) {
+		dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
+		goto done;
+	}
+
+	if (inode->i_ino == HFSPLUS_EXT_CNID)
+		return -EIO;
+
+	mutex_lock(&hip->extents_lock);
+
+	/*
+	 * hfsplus_ext_read_extent will write out a cached extent into
+	 * the extents btree.  In that case we may have to mark the inode
+	 * dirty even for a pure read of an extent here.
+	 */
+	was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
+	res = hfsplus_ext_read_extent(inode, ablock);
+	if (res) {
+		mutex_unlock(&hip->extents_lock);
+		return -EIO;
+	}
+	dblock = hfsplus_ext_find_block(hip->cached_extents,
+					ablock - hip->cached_start);
+	mutex_unlock(&hip->extents_lock);
+
+done:
+	dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n",
+		inode->i_ino, (long long)iblock, dblock);
+
+	mask = (1 << sbi->fs_shift) - 1;
+	sector = ((sector_t)dblock << sbi->fs_shift) +
+		  sbi->blockoffset + (iblock & mask);
+	map_bh(bh_result, sb, sector);
+
+	if (create) {
+		set_buffer_new(bh_result);
+		hip->phys_size += sb->s_blocksize;
+		hip->fs_blocks++;
+		inode_add_bytes(inode, sb->s_blocksize);
+	}
+	if (create || was_dirty)
+		mark_inode_dirty(inode);
+	return 0;
+}
+
+static void hfsplus_dump_extent(struct hfsplus_extent *extent)
+{
+	int i;
+
+	dprint(DBG_EXTENT, "   ");
+	for (i = 0; i < 8; i++)
+		dprint(DBG_EXTENT, " %u:%u", be32_to_cpu(extent[i].start_block),
+				 be32_to_cpu(extent[i].block_count));
+	dprint(DBG_EXTENT, "\n");
+}
+
+static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
+			      u32 alloc_block, u32 block_count)
+{
+	u32 count, start;
+	int i;
+
+	hfsplus_dump_extent(extent);
+	for (i = 0; i < 8; extent++, i++) {
+		count = be32_to_cpu(extent->block_count);
+		if (offset == count) {
+			start = be32_to_cpu(extent->start_block);
+			if (alloc_block != start + count) {
+				if (++i >= 8)
+					return -ENOSPC;
+				extent++;
+				extent->start_block = cpu_to_be32(alloc_block);
+			} else
+				block_count += count;
+			extent->block_count = cpu_to_be32(block_count);
+			return 0;
+		} else if (offset < count)
+			break;
+		offset -= count;
+	}
+	/* panic? */
+	return -EIO;
+}
+
+static int hfsplus_free_extents(struct super_block *sb,
+				struct hfsplus_extent *extent,
+				u32 offset, u32 block_nr)
+{
+	u32 count, start;
+	int i;
+
+	hfsplus_dump_extent(extent);
+	for (i = 0; i < 8; extent++, i++) {
+		count = be32_to_cpu(extent->block_count);
+		if (offset == count)
+			goto found;
+		else if (offset < count)
+			break;
+		offset -= count;
+	}
+	/* panic? */
+	return -EIO;
+found:
+	for (;;) {
+		start = be32_to_cpu(extent->start_block);
+		if (count <= block_nr) {
+			hfsplus_block_free(sb, start, count);
+			extent->block_count = 0;
+			extent->start_block = 0;
+			block_nr -= count;
+		} else {
+			count -= block_nr;
+			hfsplus_block_free(sb, start + count, block_nr);
+			extent->block_count = cpu_to_be32(count);
+			block_nr = 0;
+		}
+		if (!block_nr || !i)
+			return 0;
+		i--;
+		extent--;
+		count = be32_to_cpu(extent->block_count);
+	}
+}
+
+int hfsplus_free_fork(struct super_block *sb, u32 cnid,
+		struct hfsplus_fork_raw *fork, int type)
+{
+	struct hfs_find_data fd;
+	hfsplus_extent_rec ext_entry;
+	u32 total_blocks, blocks, start;
+	int res, i;
+
+	total_blocks = be32_to_cpu(fork->total_blocks);
+	if (!total_blocks)
+		return 0;
+
+	blocks = 0;
+	for (i = 0; i < 8; i++)
+		blocks += be32_to_cpu(fork->extents[i].block_count);
+
+	res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
+	if (res)
+		return res;
+	if (total_blocks == blocks)
+		return 0;
+
+	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
+	if (res)
+		return res;
+	do {
+		res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
+						total_blocks, type);
+		if (res)
+			break;
+		start = be32_to_cpu(fd.key->ext.start_block);
+		hfsplus_free_extents(sb, ext_entry,
+				     total_blocks - start,
+				     total_blocks);
+		hfs_brec_remove(&fd);
+		total_blocks = start;
+	} while (total_blocks > blocks);
+	hfs_find_exit(&fd);
+
+	return res;
+}
+
+int hfsplus_file_extend(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	u32 start, len, goal;
+	int res;
+
+	if (sbi->alloc_file->i_size * 8 <
+	    sbi->total_blocks - sbi->free_blocks + 8) {
+		/* extend alloc file */
+		printk(KERN_ERR "hfs: extend alloc file! "
+				"(%llu,%u,%u)\n",
+			sbi->alloc_file->i_size * 8,
+			sbi->total_blocks, sbi->free_blocks);
+		return -ENOSPC;
+	}
+
+	mutex_lock(&hip->extents_lock);
+	if (hip->alloc_blocks == hip->first_blocks)
+		goal = hfsplus_ext_lastblock(hip->first_extents);
+	else {
+		res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
+		if (res)
+			goto out;
+		goal = hfsplus_ext_lastblock(hip->cached_extents);
+	}
+
+	len = hip->clump_blocks;
+	start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
+	if (start >= sbi->total_blocks) {
+		start = hfsplus_block_allocate(sb, goal, 0, &len);
+		if (start >= goal) {
+			res = -ENOSPC;
+			goto out;
+		}
+	}
+
+	dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
+
+	if (hip->alloc_blocks <= hip->first_blocks) {
+		if (!hip->first_blocks) {
+			dprint(DBG_EXTENT, "first extents\n");
+			/* no extents yet */
+			hip->first_extents[0].start_block = cpu_to_be32(start);
+			hip->first_extents[0].block_count = cpu_to_be32(len);
+			res = 0;
+		} else {
+			/* try to append to extents in inode */
+			res = hfsplus_add_extent(hip->first_extents,
+						 hip->alloc_blocks,
+						 start, len);
+			if (res == -ENOSPC)
+				goto insert_extent;
+		}
+		if (!res) {
+			hfsplus_dump_extent(hip->first_extents);
+			hip->first_blocks += len;
+		}
+	} else {
+		res = hfsplus_add_extent(hip->cached_extents,
+					 hip->alloc_blocks - hip->cached_start,
+					 start, len);
+		if (!res) {
+			hfsplus_dump_extent(hip->cached_extents);
+			hip->extent_state |= HFSPLUS_EXT_DIRTY;
+			hip->cached_blocks += len;
+		} else if (res == -ENOSPC)
+			goto insert_extent;
+	}
+out:
+	mutex_unlock(&hip->extents_lock);
+	if (!res) {
+		hip->alloc_blocks += len;
+		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
+	}
+	return res;
+
+insert_extent:
+	dprint(DBG_EXTENT, "insert new extent\n");
+	res = hfsplus_ext_write_extent_locked(inode);
+	if (res)
+		goto out;
+
+	memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
+	hip->cached_extents[0].start_block = cpu_to_be32(start);
+	hip->cached_extents[0].block_count = cpu_to_be32(len);
+	hfsplus_dump_extent(hip->cached_extents);
+	hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
+	hip->cached_start = hip->alloc_blocks;
+	hip->cached_blocks = len;
+
+	res = 0;
+	goto out;
+}
+
+void hfsplus_file_truncate(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	struct hfs_find_data fd;
+	u32 alloc_cnt, blk_cnt, start;
+	int res;
+
+	dprint(DBG_INODE, "truncate: %lu, %llu -> %llu\n",
+		inode->i_ino, (long long)hip->phys_size,
+		inode->i_size);
+
+	if (inode->i_size > hip->phys_size) {
+		struct address_space *mapping = inode->i_mapping;
+		struct page *page;
+		void *fsdata;
+		u32 size = inode->i_size;
+
+		res = pagecache_write_begin(NULL, mapping, size, 0,
+						AOP_FLAG_UNINTERRUPTIBLE,
+						&page, &fsdata);
+		if (res)
+			return;
+		res = pagecache_write_end(NULL, mapping, size,
+			0, 0, page, fsdata);
+		if (res < 0)
+			return;
+		mark_inode_dirty(inode);
+		return;
+	} else if (inode->i_size == hip->phys_size)
+		return;
+
+	blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
+			HFSPLUS_SB(sb)->alloc_blksz_shift;
+	alloc_cnt = hip->alloc_blocks;
+	if (blk_cnt == alloc_cnt)
+		goto out;
+
+	mutex_lock(&hip->extents_lock);
+	res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
+	if (res) {
+		mutex_unlock(&hip->extents_lock);
+		/* XXX: We lack error handling of hfsplus_file_truncate() */
+		return;
+	}
+	while (1) {
+		if (alloc_cnt == hip->first_blocks) {
+			hfsplus_free_extents(sb, hip->first_extents,
+					     alloc_cnt, alloc_cnt - blk_cnt);
+			hfsplus_dump_extent(hip->first_extents);
+			hip->first_blocks = blk_cnt;
+			break;
+		}
+		res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
+		if (res)
+			break;
+		start = hip->cached_start;
+		hfsplus_free_extents(sb, hip->cached_extents,
+				     alloc_cnt - start, alloc_cnt - blk_cnt);
+		hfsplus_dump_extent(hip->cached_extents);
+		if (blk_cnt > start) {
+			hip->extent_state |= HFSPLUS_EXT_DIRTY;
+			break;
+		}
+		alloc_cnt = start;
+		hip->cached_start = hip->cached_blocks = 0;
+		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
+		hfs_brec_remove(&fd);
+	}
+	hfs_find_exit(&fd);
+	mutex_unlock(&hip->extents_lock);
+
+	hip->alloc_blocks = blk_cnt;
+out:
+	hip->phys_size = inode->i_size;
+	hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
+		sb->s_blocksize_bits;
+	inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
+	hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
+}