1 files changed, 1041 insertions, 0 deletions

diff --git a/exfat/libexfat/node.c b/exfat/libexfat/node.c
new file mode 100644
index 000000000..bacb01d10
--- /dev/null
+++ b/exfat/libexfat/node.c
@@ -0,0 +1,1041 @@
+/*
+	node.c (09.10.09)
+	exFAT file system implementation library.
+
+	Copyright (C) 2010-2012  Andrew Nayenko
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	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 License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "exfat.h"
+#include <errno.h>
+#include <string.h>
+#include <inttypes.h>
+
+/* on-disk nodes iterator */
+struct iterator
+{
+	cluster_t cluster;
+	off64_t offset;
+	int contiguous;
+	char* chunk;
+};
+
+struct exfat_node* exfat_get_node(struct exfat_node* node)
+{
+	/* if we switch to multi-threaded mode we will need atomic
+	   increment here and atomic decrement in exfat_put_node() */
+	node->references++;
+	return node;
+}
+
+void exfat_put_node(struct exfat* ef, struct exfat_node* node)
+{
+	if (--node->references < 0)
+	{
+		char buffer[EXFAT_NAME_MAX + 1];
+		exfat_get_name(node, buffer, EXFAT_NAME_MAX);
+		exfat_bug("reference counter of `%s' is below zero", buffer);
+	}
+
+	if (node->references == 0)
+	{
+		if (node->flags & EXFAT_ATTRIB_DIRTY)
+			exfat_flush_node(ef, node);
+		if (node->flags & EXFAT_ATTRIB_UNLINKED)
+		{
+			/* free all clusters and node structure itself */
+			exfat_truncate(ef, node, 0);
+			free(node);
+		}
+		if (ef->cmap.dirty)
+			exfat_flush_cmap(ef);
+	}
+}
+
+/**
+ * Cluster + offset from the beginning of the directory to absolute offset.
+ */
+static off64_t co2o(struct exfat* ef, cluster_t cluster, off64_t offset)
+{
+	return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
+}
+
+static int opendir(struct exfat* ef, const struct exfat_node* dir,
+		struct iterator* it)
+{
+	if (!(dir->flags & EXFAT_ATTRIB_DIR))
+		exfat_bug("not a directory");
+	it->cluster = dir->start_cluster;
+	it->offset = 0;
+	it->contiguous = IS_CONTIGUOUS(*dir);
+	it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
+	if (it->chunk == NULL)
+	{
+		exfat_error("out of memory");
+		return -ENOMEM;
+	}
+	exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
+			exfat_c2o(ef, it->cluster));
+	return 0;
+}
+
+static void closedir(struct iterator* it)
+{
+	it->cluster = 0;
+	it->offset = 0;
+	it->contiguous = 0;
+	free(it->chunk);
+	it->chunk = NULL;
+}
+
+static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
+		struct iterator* it)
+{
+	/* move iterator to the next entry in the directory */
+	it->offset += sizeof(struct exfat_entry);
+	/* fetch the next cluster if needed */
+	if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
+	{
+		/* reached the end of directory; the caller should check this
+		   condition too */
+		if (it->offset >= parent->size)
+			return 0;
+		it->cluster = exfat_next_cluster(ef, parent, it->cluster);
+		if (CLUSTER_INVALID(it->cluster))
+		{
+			exfat_error("invalid cluster 0x%x while reading directory",
+					it->cluster);
+			return 1;
+		}
+		exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
+				exfat_c2o(ef, it->cluster));
+	}
+	return 0;
+}
+
+static struct exfat_node* allocate_node(void)
+{
+	struct exfat_node* node = malloc(sizeof(struct exfat_node));
+	if (node == NULL)
+	{
+		exfat_error("failed to allocate node");
+		return NULL;
+	}
+	memset(node, 0, sizeof(struct exfat_node));
+	return node;
+}
+
+static void init_node_meta1(struct exfat_node* node,
+		const struct exfat_entry_meta1* meta1)
+{
+	node->flags = le16_to_cpu(meta1->attrib);
+	node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
+			meta1->mtime_cs);
+	/* there is no centiseconds field for atime */
+	node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
+}
+
+static void init_node_meta2(struct exfat_node* node,
+		const struct exfat_entry_meta2* meta2)
+{
+	node->size = le64_to_cpu(meta2->size);
+	node->start_cluster = le32_to_cpu(meta2->start_cluster);
+	node->fptr_cluster = node->start_cluster;
+	if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
+		node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
+}
+
+static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
+		const struct iterator* it)
+{
+	return (const struct exfat_entry*)
+			(it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
+}
+
+/*
+ * Reads one entry in directory at position pointed by iterator and fills
+ * node structure.
+ */
+static int readdir(struct exfat* ef, const struct exfat_node* parent,
+		struct exfat_node** node, struct iterator* it)
+{
+	int rc = -EIO;
+	const struct exfat_entry* entry;
+	const struct exfat_entry_meta1* meta1;
+	const struct exfat_entry_meta2* meta2;
+	const struct exfat_entry_name* file_name;
+	const struct exfat_entry_upcase* upcase;
+	const struct exfat_entry_bitmap* bitmap;
+	const struct exfat_entry_label* label;
+	uint8_t continuations = 0;
+	le16_t* namep = NULL;
+	uint16_t reference_checksum = 0;
+	uint16_t actual_checksum = 0;
+	uint64_t real_size = 0;
+
+	*node = NULL;
+
+	for (;;)
+	{
+		if (it->offset >= parent->size)
+		{
+			if (continuations != 0)
+			{
+				exfat_error("expected %hhu continuations", continuations);
+				goto error;
+			}
+			return -ENOENT; /* that's OK, means end of directory */
+		}
+
+		entry = get_entry_ptr(ef, it);
+		switch (entry->type)
+		{
+		case EXFAT_ENTRY_FILE:
+			if (continuations != 0)
+			{
+				exfat_error("expected %hhu continuations before new entry",
+						continuations);
+				goto error;
+			}
+			meta1 = (const struct exfat_entry_meta1*) entry;
+			continuations = meta1->continuations;
+			/* each file entry must have at least 2 continuations:
+			   info and name */
+			if (continuations < 2)
+			{
+				exfat_error("too few continuations (%hhu)", continuations);
+				goto error;
+			}
+			reference_checksum = le16_to_cpu(meta1->checksum);
+			actual_checksum = exfat_start_checksum(meta1);
+			*node = allocate_node();
+			if (*node == NULL)
+			{
+				rc = -ENOMEM;
+				goto error;
+			}
+			/* new node has zero reference counter */
+			(*node)->entry_cluster = it->cluster;
+			(*node)->entry_offset = it->offset;
+			init_node_meta1(*node, meta1);
+			namep = (*node)->name;
+			break;
+
+		case EXFAT_ENTRY_FILE_INFO:
+			if (continuations < 2)
+			{
+				exfat_error("unexpected continuation (%hhu)",
+						continuations);
+				goto error;
+			}
+			meta2 = (const struct exfat_entry_meta2*) entry;
+			if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
+			{
+				exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
+				goto error;
+			}
+			init_node_meta2(*node, meta2);
+			actual_checksum = exfat_add_checksum(entry, actual_checksum);
+			real_size = le64_to_cpu(meta2->real_size);
+			/* empty files must be marked as non-contiguous */
+			if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
+			{
+				exfat_error("empty file marked as contiguous (0x%hhx)",
+						meta2->flags);
+				goto error;
+			}
+			/* directories must be aligned on at cluster boundary */
+			if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
+				(*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
+			{
+				exfat_error("directory has invalid size %"PRIu64" bytes",
+						(*node)->size);
+				goto error;
+			}
+			--continuations;
+			break;
+
+		case EXFAT_ENTRY_FILE_NAME:
+			if (continuations == 0)
+			{
+				exfat_error("unexpected continuation");
+				goto error;
+			}
+			file_name = (const struct exfat_entry_name*) entry;
+			actual_checksum = exfat_add_checksum(entry, actual_checksum);
+
+			memcpy(namep, file_name->name, EXFAT_ENAME_MAX * sizeof(le16_t));
+			namep += EXFAT_ENAME_MAX;
+			if (--continuations == 0)
+			{
+				/*
+				   There are two fields that contain file size. Maybe they
+				   plan to add compression support in the future and one of
+				   those fields is visible (uncompressed) size and the other
+				   is real (compressed) size. Anyway, currently it looks like
+				   exFAT does not support compression and both fields must be
+				   equal.
+
+				   There is an exception though: pagefile.sys (its real_size
+				   is always 0).
+				*/
+				if (real_size != (*node)->size)
+				{
+					char buffer[EXFAT_NAME_MAX + 1];
+
+					exfat_get_name(*node, buffer, EXFAT_NAME_MAX);
+					exfat_error("`%s' real size does not equal to size "
+							"(%"PRIu64" != %"PRIu64")", buffer,
+							real_size, (*node)->size);
+					goto error;
+				}
+				if (actual_checksum != reference_checksum)
+				{
+					char buffer[EXFAT_NAME_MAX + 1];
+
+					exfat_get_name(*node, buffer, EXFAT_NAME_MAX);
+					exfat_error("`%s' has invalid checksum (0x%hx != 0x%hx)",
+							buffer, actual_checksum, reference_checksum);
+					goto error;
+				}
+				if (fetch_next_entry(ef, parent, it) != 0)
+					goto error;
+				return 0; /* entry completed */
+			}
+			break;
+
+		case EXFAT_ENTRY_UPCASE:
+			if (ef->upcase != NULL)
+				break;
+			upcase = (const struct exfat_entry_upcase*) entry;
+			if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
+			{
+				exfat_error("invalid cluster 0x%x in upcase table",
+						le32_to_cpu(upcase->start_cluster));
+				goto error;
+			}
+			if (le64_to_cpu(upcase->size) == 0 ||
+				le64_to_cpu(upcase->size) > 0xffff * sizeof(uint16_t) ||
+				le64_to_cpu(upcase->size) % sizeof(uint16_t) != 0)
+			{
+				exfat_error("bad upcase table size (%"PRIu64" bytes)",
+						le64_to_cpu(upcase->size));
+				goto error;
+			}
+			ef->upcase = malloc(le64_to_cpu(upcase->size));
+			if (ef->upcase == NULL)
+			{
+				exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
+						le64_to_cpu(upcase->size));
+				rc = -ENOMEM;
+				goto error;
+			}
+			ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
+
+			exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
+					exfat_c2o(ef, le32_to_cpu(upcase->start_cluster)));
+			break;
+
+		case EXFAT_ENTRY_BITMAP:
+			bitmap = (const struct exfat_entry_bitmap*) entry;
+			ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
+			if (CLUSTER_INVALID(ef->cmap.start_cluster))
+			{
+				exfat_error("invalid cluster 0x%x in clusters bitmap",
+						ef->cmap.start_cluster);
+				goto error;
+			}
+			ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
+				EXFAT_FIRST_DATA_CLUSTER;
+			if (le64_to_cpu(bitmap->size) < (ef->cmap.size + 7) / 8)
+			{
+				exfat_error("invalid clusters bitmap size: %"PRIu64
+						" (expected at least %u)",
+						le64_to_cpu(bitmap->size), (ef->cmap.size + 7) / 8);
+				goto error;
+			}
+			/* FIXME bitmap can be rather big, up to 512 MB */
+			ef->cmap.chunk_size = ef->cmap.size;
+			ef->cmap.chunk = malloc(le64_to_cpu(bitmap->size));
+			if (ef->cmap.chunk == NULL)
+			{
+				exfat_error("failed to allocate clusters bitmap chunk "
+						"(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
+				rc = -ENOMEM;
+				goto error;
+			}
+
+			exfat_pread(ef->dev, ef->cmap.chunk, le64_to_cpu(bitmap->size),
+					exfat_c2o(ef, ef->cmap.start_cluster));
+			break;
+
+		case EXFAT_ENTRY_LABEL:
+			label = (const struct exfat_entry_label*) entry;
+			if (label->length > EXFAT_ENAME_MAX)
+			{
+				exfat_error("too long label (%hhu chars)", label->length);
+				goto error;
+			}
+			if (utf16_to_utf8(ef->label, label->name,
+						sizeof(ef->label), EXFAT_ENAME_MAX) != 0)
+				goto error;
+			break;
+
+		default:
+			if (entry->type & EXFAT_ENTRY_VALID)
+			{
+				exfat_error("unknown entry type 0x%hhx", entry->type);
+				goto error;
+			}
+			break;
+		}
+
+		if (fetch_next_entry(ef, parent, it) != 0)
+			goto error;
+	}
+	/* we never reach here */
+
+error:
+	free(*node);
+	*node = NULL;
+	return rc;
+}
+
+int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
+{
+	struct iterator it;
+	int rc;
+	struct exfat_node* node;
+	struct exfat_node* current = NULL;
+
+	if (dir->flags & EXFAT_ATTRIB_CACHED)
+		return 0; /* already cached */
+
+	rc = opendir(ef, dir, &it);
+	if (rc != 0)
+		return rc;
+	while ((rc = readdir(ef, dir, &node, &it)) == 0)
+	{
+		node->parent = dir;
+		if (current != NULL)
+		{
+			current->next = node;
+			node->prev = current;
+		}
+		else
+			dir->child = node;
+
+		current = node;
+	}
+	closedir(&it);
+
+	if (rc != -ENOENT)
+	{
+		/* rollback */
+		for (current = dir->child; current; current = node)
+		{
+			node = current->next;
+			free(current);
+		}
+		dir->child = NULL;
+		return rc;
+	}
+
+	dir->flags |= EXFAT_ATTRIB_CACHED;
+	return 0;
+}
+
+static void reset_cache(struct exfat* ef, struct exfat_node* node)
+{
+	struct exfat_node* child;
+	struct exfat_node* next;
+
+	for (child = node->child; child; child = next)
+	{
+		reset_cache(ef, child);
+		next = child->next;
+		free(child);
+	}
+	if (node->references != 0)
+	{
+		char buffer[EXFAT_NAME_MAX + 1];
+		exfat_get_name(node, buffer, EXFAT_NAME_MAX);
+		exfat_warn("non-zero reference counter (%d) for `%s'",
+				node->references, buffer);
+	}
+	while (node->references--)
+		exfat_put_node(ef, node);
+	node->child = NULL;
+	node->flags &= ~EXFAT_ATTRIB_CACHED;
+}
+
+void exfat_reset_cache(struct exfat* ef)
+{
+	reset_cache(ef, ef->root);
+}
+
+void next_entry(struct exfat* ef, const struct exfat_node* parent,
+		cluster_t* cluster, off64_t* offset)
+{
+	*offset += sizeof(struct exfat_entry);
+	if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
+		/* next cluster cannot be invalid */
+		*cluster = exfat_next_cluster(ef, parent, *cluster);
+}
+
+void exfat_flush_node(struct exfat* ef, struct exfat_node* node)
+{
+	cluster_t cluster;
+	off64_t offset;
+	off64_t meta1_offset, meta2_offset;
+	struct exfat_entry_meta1 meta1;
+	struct exfat_entry_meta2 meta2;
+
+	if (ef->ro)
+		exfat_bug("unable to flush node to read-only FS");
+
+	if (node->parent == NULL)
+		return; /* do not flush unlinked node */
+
+	cluster = node->entry_cluster;
+	offset = node->entry_offset;
+	meta1_offset = co2o(ef, cluster, offset);
+	next_entry(ef, node->parent, &cluster, &offset);
+	meta2_offset = co2o(ef, cluster, offset);
+
+	exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset);
+	if (meta1.type != EXFAT_ENTRY_FILE)
+		exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
+	meta1.attrib = cpu_to_le16(node->flags);
+	exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
+	exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
+
+	exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset);
+	if (meta2.type != EXFAT_ENTRY_FILE_INFO)
+		exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
+	meta2.size = meta2.real_size = cpu_to_le64(node->size);
+	meta2.start_cluster = cpu_to_le32(node->start_cluster);
+	meta2.flags = EXFAT_FLAG_ALWAYS1;
+	/* empty files must not be marked as contiguous */
+	if (node->size != 0 && IS_CONTIGUOUS(*node))
+		meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
+	/* name hash remains unchanged, no need to recalculate it */
+
+	meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
+
+	exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset);
+	exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset);
+
+	node->flags &= ~EXFAT_ATTRIB_DIRTY;
+}
+
+static void erase_entry(struct exfat* ef, struct exfat_node* node)
+{
+	cluster_t cluster = node->entry_cluster;
+	off64_t offset = node->entry_offset;
+	int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
+	uint8_t entry_type;
+
+	entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
+	exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset));
+
+	next_entry(ef, node->parent, &cluster, &offset);
+	entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
+	exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset));
+
+	while (name_entries--)
+	{
+		next_entry(ef, node->parent, &cluster, &offset);
+		entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
+		exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset));
+	}
+}
+
+static void tree_detach(struct exfat_node* node)
+{
+	if (node->prev)
+		node->prev->next = node->next;
+	else /* this is the first node in the list */
+		node->parent->child = node->next;
+	if (node->next)
+		node->next->prev = node->prev;
+	node->parent = NULL;
+	node->prev = NULL;
+	node->next = NULL;
+}
+
+static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
+{
+	node->parent = dir;
+	if (dir->child)
+	{
+		dir->child->prev = node;
+		node->next = dir->child;
+	}
+	dir->child = node;
+}
+
+static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
+		off64_t deleted_offset)
+{
+	const struct exfat_node* node;
+	const struct exfat_node* last_node;
+	uint64_t entries = 0;
+	uint64_t new_size;
+	int rc;
+
+	if (!(dir->flags & EXFAT_ATTRIB_DIR))
+		exfat_bug("attempted to shrink a file");
+	if (!(dir->flags & EXFAT_ATTRIB_CACHED))
+		exfat_bug("attempted to shrink uncached directory");
+
+	for (last_node = node = dir->child; node; node = node->next)
+	{
+		if (deleted_offset < node->entry_offset)
+		{
+			/* there are other entries after the removed one, no way to shrink
+			   this directory */
+			return 0;
+		}
+		if (last_node->entry_offset < node->entry_offset)
+			last_node = node;
+	}
+
+	if (last_node)
+	{
+		/* offset of the last entry */
+		entries += last_node->entry_offset / sizeof(struct exfat_entry);
+		/* two subentries with meta info */
+		entries += 2;
+		/* subentries with file name */
+		entries += DIV_ROUND_UP(utf16_length(last_node->name),
+				EXFAT_ENAME_MAX);
+	}
+
+	new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
+				 CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
+	if (new_size == 0) /* directory always has at least 1 cluster */
+		new_size = CLUSTER_SIZE(*ef->sb);
+	if (new_size == dir->size)
+		return 0;
+	rc = exfat_truncate(ef, dir, new_size);
+	if (rc != 0)
+		return rc;
+	return 0;
+}
+
+static int delete(struct exfat* ef, struct exfat_node* node)
+{
+	struct exfat_node* parent = node->parent;
+	off64_t deleted_offset = node->entry_offset;
+	int rc;
+
+	exfat_get_node(parent);
+	erase_entry(ef, node);
+	exfat_update_mtime(parent);
+	tree_detach(node);
+	rc = shrink_directory(ef, parent, deleted_offset);
+	exfat_put_node(ef, parent);
+	/* file clusters will be freed when node reference counter becomes 0 */
+	node->flags |= EXFAT_ATTRIB_UNLINKED;
+	return rc;
+}
+
+int exfat_unlink(struct exfat* ef, struct exfat_node* node)
+{
+	if (node->flags & EXFAT_ATTRIB_DIR)
+		return -EISDIR;
+	return delete(ef, node);
+}
+
+int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
+{
+	if (!(node->flags & EXFAT_ATTRIB_DIR))
+		return -ENOTDIR;
+	/* check that directory is empty */
+	exfat_cache_directory(ef, node);
+	if (node->child)
+		return -ENOTEMPTY;
+	return delete(ef, node);
+}
+
+static int grow_directory(struct exfat* ef, struct exfat_node* dir,
+		uint64_t asize, uint32_t difference)
+{
+	return exfat_truncate(ef, dir,
+			DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
+				* CLUSTER_SIZE(*ef->sb));
+}
+
+static int find_slot(struct exfat* ef, struct exfat_node* dir,
+		cluster_t* cluster, off64_t* offset, int subentries)
+{
+	struct iterator it;
+	int rc;
+	const struct exfat_entry* entry;
+	int contiguous = 0;
+
+	rc = opendir(ef, dir, &it);
+	if (rc != 0)
+		return rc;
+	for (;;)
+	{
+		if (contiguous == 0)
+		{
+			*cluster = it.cluster;
+			*offset = it.offset;
+		}
+		entry = get_entry_ptr(ef, &it);
+		if (entry->type & EXFAT_ENTRY_VALID)
+			contiguous = 0;
+		else
+			contiguous++;
+		if (contiguous == subentries)
+			break;	/* suitable slot is found */
+		if (it.offset + sizeof(struct exfat_entry) >= dir->size)
+		{
+			rc = grow_directory(ef, dir, dir->size,
+					(subentries - contiguous) * sizeof(struct exfat_entry));
+			if (rc != 0)
+			{
+				closedir(&it);
+				return rc;
+			}
+		}
+		if (fetch_next_entry(ef, dir, &it) != 0)
+		{
+			closedir(&it);
+			return -EIO;
+		}
+	}
+	closedir(&it);
+	return 0;
+}
+
+static int write_entry(struct exfat* ef, struct exfat_node* dir,
+		const le16_t* name, cluster_t cluster, off64_t offset, uint16_t attrib)
+{
+	struct exfat_node* node;
+	struct exfat_entry_meta1 meta1;
+	struct exfat_entry_meta2 meta2;
+	const size_t name_length = utf16_length(name);
+	const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
+	int i;
+
+	node = allocate_node();
+	if (node == NULL)
+		return -ENOMEM;
+	node->entry_cluster = cluster;
+	node->entry_offset = offset;
+	memcpy(node->name, name, name_length * sizeof(le16_t));
+
+	memset(&meta1, 0, sizeof(meta1));
+	meta1.type = EXFAT_ENTRY_FILE;
+	meta1.continuations = 1 + name_entries;
+	meta1.attrib = cpu_to_le16(attrib);
+	exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
+			&meta1.crtime_cs);
+	meta1.adate = meta1.mdate = meta1.crdate;
+	meta1.atime = meta1.mtime = meta1.crtime;
+	meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
+
+	memset(&meta2, 0, sizeof(meta2));
+	meta2.type = EXFAT_ENTRY_FILE_INFO;
+	meta2.flags = EXFAT_FLAG_ALWAYS1;
+	meta2.name_length = name_length;
+	meta2.name_hash = exfat_calc_name_hash(ef, node->name);
+	meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
+
+	meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
+
+	exfat_pwrite(ef->dev, &meta1, sizeof(meta1), co2o(ef, cluster, offset));
+	next_entry(ef, dir, &cluster, &offset);
+	exfat_pwrite(ef->dev, &meta2, sizeof(meta2), co2o(ef, cluster, offset));
+	for (i = 0; i < name_entries; i++)
+	{
+		struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
+		memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
+				EXFAT_ENAME_MAX * sizeof(le16_t));
+		next_entry(ef, dir, &cluster, &offset);
+		exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
+				co2o(ef, cluster, offset));
+	}
+
+	init_node_meta1(node, &meta1);
+	init_node_meta2(node, &meta2);
+
+	tree_attach(dir, node);
+	exfat_update_mtime(dir);
+	return 0;
+}
+
+static int create(struct exfat* ef, const char* path, uint16_t attrib)
+{
+	struct exfat_node* dir;
+	struct exfat_node* existing;
+	cluster_t cluster = EXFAT_CLUSTER_BAD;
+	off64_t offset = -1;
+	le16_t name[EXFAT_NAME_MAX + 1];
+	int rc;
+
+	rc = exfat_split(ef, &dir, &existing, name, path);
+	if (rc != 0)
+		return rc;
+	if (existing != NULL)
+	{
+		exfat_put_node(ef, existing);
+		exfat_put_node(ef, dir);
+		return -EEXIST;
+	}
+
+	rc = find_slot(ef, dir, &cluster, &offset,
+			2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
+	if (rc != 0)
+	{
+		exfat_put_node(ef, dir);
+		return rc;
+	}
+	rc = write_entry(ef, dir, name, cluster, offset, attrib);
+	exfat_put_node(ef, dir);
+	return rc;
+}
+
+int exfat_mknod(struct exfat* ef, const char* path)
+{
+	return create(ef, path, EXFAT_ATTRIB_ARCH);
+}
+
+int exfat_mkdir(struct exfat* ef, const char* path)
+{
+	int rc;
+	struct exfat_node* node;
+
+	rc = create(ef, path, EXFAT_ATTRIB_ARCH | EXFAT_ATTRIB_DIR);
+	if (rc != 0)
+		return rc;
+	rc = exfat_lookup(ef, &node, path);
+	if (rc != 0)
+		return 0;
+	/* directories always have at least one cluster */
+	rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb));
+	if (rc != 0)
+	{
+		delete(ef, node);
+		exfat_put_node(ef, node);
+		return rc;
+	}
+	exfat_put_node(ef, node);
+	return 0;
+}
+
+static void rename_entry(struct exfat* ef, struct exfat_node* dir,
+		struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
+		off64_t new_offset)
+{
+	struct exfat_entry_meta1 meta1;
+	struct exfat_entry_meta2 meta2;
+	cluster_t old_cluster = node->entry_cluster;
+	off64_t old_offset = node->entry_offset;
+	const size_t name_length = utf16_length(name);
+	const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
+	int i;
+
+	exfat_pread(ef->dev, &meta1, sizeof(meta1),
+			co2o(ef, old_cluster, old_offset));
+	next_entry(ef, node->parent, &old_cluster, &old_offset);
+	exfat_pread(ef->dev, &meta2, sizeof(meta2),
+			co2o(ef, old_cluster, old_offset));
+	meta1.continuations = 1 + name_entries;
+	meta2.name_hash = exfat_calc_name_hash(ef, name);
+	meta2.name_length = name_length;
+	meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
+
+	erase_entry(ef, node);
+
+	node->entry_cluster = new_cluster;
+	node->entry_offset = new_offset;
+
+	exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
+			co2o(ef, new_cluster, new_offset));
+	next_entry(ef, dir, &new_cluster, &new_offset);
+	exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
+			co2o(ef, new_cluster, new_offset));
+
+	for (i = 0; i < name_entries; i++)
+	{
+		struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
+		memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
+				EXFAT_ENAME_MAX * sizeof(le16_t));
+		next_entry(ef, dir, &new_cluster, &new_offset);
+		exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
+				co2o(ef, new_cluster, new_offset));
+	}
+
+	memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
+	tree_detach(node);
+	tree_attach(dir, node);
+}
+
+int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
+{
+	struct exfat_node* node;
+	struct exfat_node* existing;
+	struct exfat_node* dir;
+	cluster_t cluster = EXFAT_CLUSTER_BAD;
+	off64_t offset = -1;
+	le16_t name[EXFAT_NAME_MAX + 1];
+	int rc;
+
+	rc = exfat_lookup(ef, &node, old_path);
+	if (rc != 0)
+		return rc;
+
+	rc = exfat_split(ef, &dir, &existing, name, new_path);
+	if (rc != 0)
+	{
+		exfat_put_node(ef, node);
+		return rc;
+	}
+	if (existing != NULL)
+	{
+		/* remove target if it's not the same node as source */
+		if (existing != node)
+		{
+			if (existing->flags & EXFAT_ATTRIB_DIR)
+			{
+				if (node->flags & EXFAT_ATTRIB_DIR)
+					rc = exfat_rmdir(ef, existing);
+				else
+					rc = -ENOTDIR;
+			}
+			else
+			{
+				if (!(node->flags & EXFAT_ATTRIB_DIR))
+					rc = exfat_unlink(ef, existing);
+				else
+					rc = -EISDIR;
+			}
+			exfat_put_node(ef, existing);
+			if (rc != 0)
+			{
+				exfat_put_node(ef, dir);
+				exfat_put_node(ef, node);
+				return rc;
+			}
+		}
+		else
+			exfat_put_node(ef, existing);
+	}
+
+	rc = find_slot(ef, dir, &cluster, &offset,
+			2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
+	if (rc != 0)
+	{
+		exfat_put_node(ef, dir);
+		exfat_put_node(ef, node);
+		return rc;
+	}
+	rename_entry(ef, dir, node, name, cluster, offset);
+	exfat_put_node(ef, dir);
+	exfat_put_node(ef, node);
+	return 0;
+}
+
+void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
+{
+	node->atime = tv[0].tv_sec;
+	node->mtime = tv[1].tv_sec;
+	node->flags |= EXFAT_ATTRIB_DIRTY;
+}
+
+void exfat_update_atime(struct exfat_node* node)
+{
+	node->atime = time(NULL);
+	node->flags |= EXFAT_ATTRIB_DIRTY;
+}
+
+void exfat_update_mtime(struct exfat_node* node)
+{
+	node->mtime = time(NULL);
+	node->flags |= EXFAT_ATTRIB_DIRTY;
+}
+
+const char* exfat_get_label(struct exfat* ef)
+{
+	return ef->label;
+}
+
+static int find_label(struct exfat* ef, cluster_t* cluster, off64_t* offset)
+{
+	struct iterator it;
+	int rc;
+
+	rc = opendir(ef, ef->root, &it);
+	if (rc != 0)
+		return rc;
+
+	for (;;)
+	{
+		if (it.offset >= ef->root->size)
+		{
+			closedir(&it);
+			return -ENOENT;
+		}
+
+		if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
+		{
+			*cluster = it.cluster;
+			*offset = it.offset;
+			closedir(&it);
+			return 0;
+		}
+
+		if (fetch_next_entry(ef, ef->root, &it) != 0)
+		{
+			closedir(&it);
+			return -EIO;
+		}
+	}
+}
+
+int exfat_set_label(struct exfat* ef, const char* label)
+{
+	le16_t label_utf16[EXFAT_ENAME_MAX + 1];
+	int rc;
+	cluster_t cluster;
+	off64_t offset;
+	struct exfat_entry_label entry;
+
+	memset(label_utf16, 0, sizeof(label_utf16));
+	rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
+	if (rc != 0)
+		return rc;
+
+	rc = find_label(ef, &cluster, &offset);
+	if (rc == -ENOENT)
+		rc = find_slot(ef, ef->root, &cluster, &offset, 1);
+	if (rc != 0)
+		return rc;
+
+	entry.type = EXFAT_ENTRY_LABEL;
+	entry.length = utf16_length(label_utf16);
+	memcpy(entry.name, label_utf16, sizeof(entry.name));
+	if (entry.length == 0)
+		entry.type ^= EXFAT_ENTRY_VALID;
+
+	exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
+			co2o(ef, cluster, offset));
+	return 0;
+}