X-Git-Url: http://git.osdn.net/view?a=blobdiff_plain;f=libexfat%2Fnode.c;h=44f4ae320009015b83c2677a2abf03f0b599ea09;hb=cf962cdfdd7fe80ae8dac93d689c90cc55350a2a;hp=7367f192c6d89770093f7cc054a06eb37675c1d2;hpb=0c4b5cb6011dd09f5bc2132337817bd743b12bd2;p=android-x86%2Fexternal-exfat.git

diff --git a/libexfat/node.c b/libexfat/node.c
index 7367f19..44f4ae3 100644
--- a/libexfat/node.c
+++ b/libexfat/node.c
@@ -3,7 +3,7 @@
 	exFAT file system implementation library.
 
 	Free exFAT implementation.
-	Copyright (C) 2010-2013  Andrew Nayenko
+	Copyright (C) 2010-2016  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
@@ -30,7 +30,6 @@ struct iterator
 {
 	cluster_t cluster;
 	off_t offset;
-	int contiguous;
 	char* chunk;
 };
 
@@ -44,27 +43,47 @@ struct exfat_node* exfat_get_node(struct exfat_node* node)
 
 void exfat_put_node(struct exfat* ef, struct exfat_node* node)
 {
-	if (--node->references < 0)
+	char buffer[EXFAT_UTF8_NAME_BUFFER_MAX];
+
+	--node->references;
+	if (node->references < 0)
 	{
-		char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
-		exfat_get_name(node, buffer, sizeof(buffer) - 1);
-		exfat_bug("reference counter of `%s' is below zero", buffer);
+		exfat_get_name(node, buffer);
+		exfat_bug("reference counter of '%s' is below zero", buffer);
 	}
-
-	if (node->references == 0)
+	else if (node->references == 0 && node != ef->root)
 	{
-		exfat_flush_node(ef, node);
-		if (node->flags & EXFAT_ATTRIB_UNLINKED)
+		if (node->is_dirty)
 		{
-			/* free all clusters and node structure itself */
-			exfat_truncate(ef, node, 0, true);
-			free(node);
+			exfat_get_name(node, buffer);
+			exfat_warn("dirty node '%s' with zero references", buffer);
 		}
-		exfat_flush(ef);
 	}
 }
 
 /**
+ * This function must be called on rmdir and unlink (after the last
+ * exfat_put_node()) to free clusters.
+ */
+int exfat_cleanup_node(struct exfat* ef, struct exfat_node* node)
+{
+	int rc = 0;
+
+	if (node->references != 0)
+		exfat_bug("unable to cleanup a node with %d references",
+				node->references);
+
+	if (node->is_unlinked)
+	{
+		/* free all clusters and node structure itself */
+		rc = exfat_truncate(ef, node, 0, true);
+		/* free the node even in case of error or its memory will be lost */
+		free(node);
+	}
+	return rc;
+}
+
+/**
  * Cluster + offset from the beginning of the directory to absolute offset.
  */
 static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
@@ -75,21 +94,35 @@ static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
 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");
+	char buffer[EXFAT_UTF8_NAME_BUFFER_MAX];
+
+	if (!(dir->attrib & EXFAT_ATTRIB_DIR))
+	{
+		exfat_get_name(dir, buffer);
+		exfat_bug("'%s' is not a directory", buffer);
+	}
+	if (CLUSTER_INVALID(dir->start_cluster))
+	{
+		exfat_get_name(dir, buffer);
+		exfat_error("'%s' directory starts with invalid cluster %#x", buffer,
+				dir->start_cluster);
+		return -EIO;
+	}
 	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");
+		exfat_error("failed to allocate memory for directory cluster");
 		return -ENOMEM;
 	}
 	if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 			exfat_c2o(ef, it->cluster)) < 0)
 	{
-		exfat_error("failed to read directory cluster %#x", it->cluster);
+		free(it->chunk);
+		exfat_get_name(dir, buffer);
+		exfat_error("failed to read '%s' directory cluster %#x", buffer,
+				it->cluster);
 		return -EIO;
 	}
 	return 0;
@@ -99,12 +132,11 @@ 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,
+static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 		struct iterator* it)
 {
 	/* move iterator to the next entry in the directory */
@@ -115,23 +147,63 @@ static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 		/* reached the end of directory; the caller should check this
 		   condition too */
 		if (it->offset >= parent->size)
-			return 0;
+			return true;
 		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;
+			return false;
 		}
 		if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 				exfat_c2o(ef, it->cluster)) < 0)
 		{
 			exfat_error("failed to read the next directory cluster %#x",
 					it->cluster);
-			return 1;
+			return false;
 		}
 	}
-	return 0;
+	return true;
+}
+
+static int read_entries(struct exfat* ef, struct exfat_node* dir,
+		struct exfat_entry* entries, int n, off_t offset)
+{
+	ssize_t size;
+
+	if (!(dir->attrib & EXFAT_ATTRIB_DIR))
+		exfat_bug("attempted to read entries from a file");
+
+	size = exfat_generic_pread(ef, dir, entries,
+			sizeof(struct exfat_entry[n]), offset);
+	if (size == sizeof(struct exfat_entry[n]))
+		return 0; /* success */
+	if (size == 0)
+		return -ENOENT;
+	if (size < 0)
+		return -EIO;
+	exfat_error("read %zd bytes instead of %zu bytes", size,
+			sizeof(struct exfat_entry[n]));
+	return -EIO;
+}
+
+static int write_entries(struct exfat* ef, struct exfat_node* dir,
+		const struct exfat_entry* entries, int n, off_t offset)
+{
+	ssize_t size;
+
+	if (!(dir->attrib & EXFAT_ATTRIB_DIR))
+		exfat_bug("attempted to write entries into a file");
+
+	size = exfat_generic_pwrite(ef, dir, entries,
+			sizeof(struct exfat_entry[n]), offset);
+	if (size == sizeof(struct exfat_entry[n]))
+		return 0; /* success */
+	if (size < 0)
+		return -EIO;
+	exfat_error("wrote %zd bytes instead of %zu bytes", size,
+			sizeof(struct exfat_entry[n]));
+	return -EIO;
 }
 
 static struct exfat_node* allocate_node(void)
@@ -149,7 +221,8 @@ static struct exfat_node* allocate_node(void)
 static void init_node_meta1(struct exfat_node* node,
 		const struct exfat_entry_meta1* meta1)
 {
-	node->flags = le16_to_cpu(meta1->attrib);
+	node->attrib = le16_to_cpu(meta1->attrib);
+	node->continuations = meta1->continuations;
 	node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 			meta1->mtime_cs);
 	/* there is no centiseconds field for atime */
@@ -162,8 +235,7 @@ static void init_node_meta2(struct exfat_node* node,
 	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;
+	node->is_contiguous = ((meta2->flags & EXFAT_FLAG_CONTIGUOUS) != 0);
 }
 
 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
@@ -173,6 +245,100 @@ static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 			(it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 }
 
+static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
+		uint16_t reference_checksum, uint64_t valid_size, int cluster_size)
+{
+	char buffer[EXFAT_UTF8_NAME_BUFFER_MAX];
+	bool ret = true;
+
+	/*
+	   Validate checksum first. If it's invalid all other fields probably
+	   contain just garbage.
+	*/
+	if (actual_checksum != reference_checksum)
+	{
+		exfat_get_name(node, buffer);
+		exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
+				actual_checksum, reference_checksum);
+		ret = false;
+	}
+
+	/*
+	   exFAT does not support sparse files but allows files with uninitialized
+	   clusters. For such files valid_size means initialized data size and
+	   cannot be greater than file size. See SetFileValidData() function
+	   description in MSDN.
+	*/
+	if (valid_size > node->size)
+	{
+		exfat_get_name(node, buffer);
+		exfat_error("'%s' has valid size (%"PRIu64") greater than size "
+				"(%"PRIu64")", buffer, valid_size, node->size);
+		ret = false;
+	}
+
+	/*
+	   Empty file must have zero start cluster. Non-empty file must start
+	   with a valid cluster. Directories cannot be empty (i.e. must always
+	   have a valid start cluster), but we will check this later in opendir()
+	   to give user a chance to read current directory.
+	*/
+	if (node->size == 0 && node->start_cluster != EXFAT_CLUSTER_FREE)
+	{
+		exfat_get_name(node, buffer);
+		exfat_error("'%s' is empty but start cluster is %#x", buffer,
+				node->start_cluster);
+		ret = false;
+	}
+	if (node->size > 0 && CLUSTER_INVALID(node->start_cluster))
+	{
+		exfat_get_name(node, buffer);
+		exfat_error("'%s' points to invalid cluster %#x", buffer,
+				node->start_cluster);
+		ret = false;
+	}
+
+	/* Empty file or directory must be marked as non-contiguous. */
+	if (node->size == 0 && node->is_contiguous)
+	{
+		exfat_get_name(node, buffer);
+		exfat_error("'%s' is empty but marked as contiguous (%#hx)", buffer,
+				node->attrib);
+		ret = false;
+	}
+
+	/* Directory size must be aligned on at cluster boundary. */
+	if ((node->attrib & EXFAT_ATTRIB_DIR) && node->size % cluster_size != 0)
+	{
+		exfat_get_name(node, buffer);
+		exfat_error("'%s' directory size %"PRIu64" is not divisible by %d", buffer,
+				node->size, cluster_size);
+		ret = false;
+	}
+
+	return ret;
+}
+
+static void decompress_upcase(uint16_t* output, const le16_t* source,
+		size_t size)
+{
+	size_t si;
+	size_t oi;
+
+	for (oi = 0; oi < EXFAT_UPCASE_CHARS; oi++)
+		output[oi] = oi;
+
+	for (si = 0, oi = 0; si < size && oi < EXFAT_UPCASE_CHARS; si++)
+	{
+		uint16_t ch = le16_to_cpu(source[si]);
+
+		if (ch == 0xffff && si + 1 < size)	/* indicates a run */
+			oi += le16_to_cpu(source[++si]);
+		else
+			output[oi++] = ch;
+	}
+}
+
 /*
  * Reads one entry in directory at position pointed by iterator and fills
  * node structure.
@@ -192,7 +358,9 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 	le16_t* namep = NULL;
 	uint16_t reference_checksum = 0;
 	uint16_t actual_checksum = 0;
-	uint64_t real_size = 0;
+	uint64_t valid_size = 0;
+	uint64_t upcase_size = 0;
+	le16_t* upcase_comp = NULL;
 
 	*node = NULL;
 
@@ -263,22 +431,7 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 			}
 			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;
-			}
+			valid_size = le64_to_cpu(meta2->valid_size);
 			--continuations;
 			break;
 
@@ -298,37 +451,10 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 			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[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
-
-					exfat_get_name(*node, buffer, sizeof(buffer) - 1);
-					exfat_error("`%s' real size does not equal to size "
-							"(%"PRIu64" != %"PRIu64")", buffer,
-							real_size, (*node)->size);
+				if (!check_node(*node, actual_checksum, reference_checksum,
+						valid_size, CLUSTER_SIZE(*ef->sb)))
 					goto error;
-				}
-				if (actual_checksum != reference_checksum)
-				{
-					char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
-
-					exfat_get_name(*node, buffer, sizeof(buffer) - 1);
-					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)
+				if (!fetch_next_entry(ef, parent, it))
 					goto error;
 				return 0; /* entry completed */
 			}
@@ -344,33 +470,48 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 						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)
+			upcase_size = le64_to_cpu(upcase->size);
+			if (upcase_size == 0 ||
+				upcase_size > EXFAT_UPCASE_CHARS * sizeof(uint16_t) ||
+				upcase_size % sizeof(uint16_t) != 0)
 			{
 				exfat_error("bad upcase table size (%"PRIu64" bytes)",
-						le64_to_cpu(upcase->size));
+						upcase_size);
 				goto error;
 			}
-			ef->upcase = malloc(le64_to_cpu(upcase->size));
-			if (ef->upcase == NULL)
+			upcase_comp = malloc(upcase_size);
+			if (upcase_comp == NULL)
 			{
 				exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
-						le64_to_cpu(upcase->size));
+						upcase_size);
 				rc = -ENOMEM;
 				goto error;
 			}
-			ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
 
-			if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
+			/* read compressed upcase table */
+			if (exfat_pread(ef->dev, upcase_comp, upcase_size,
 					exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 			{
+				free(upcase_comp);
 				exfat_error("failed to read upper case table "
 						"(%"PRIu64" bytes starting at cluster %#x)",
-						le64_to_cpu(upcase->size),
+						upcase_size,
 						le32_to_cpu(upcase->start_cluster));
 				goto error;
 			}
+
+			/* decompress upcase table */
+			ef->upcase = calloc(EXFAT_UPCASE_CHARS, sizeof(uint16_t));
+			if (ef->upcase == NULL)
+			{
+				free(upcase_comp);
+				exfat_error("failed to allocate decompressed upcase table");
+				rc = -ENOMEM;
+				goto error;
+			}
+			decompress_upcase(ef->upcase, upcase_comp,
+					upcase_size / sizeof(uint16_t));
+			free(upcase_comp);
 			break;
 
 		case EXFAT_ENTRY_BITMAP:
@@ -422,20 +563,30 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 				goto error;
 			}
 			if (utf16_to_utf8(ef->label, label->name,
-						sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
+						sizeof(ef->label), EXFAT_ENAME_MAX) != 0)
 				goto error;
 			break;
 
 		default:
-			if (entry->type & EXFAT_ENTRY_VALID)
+			if (!(entry->type & EXFAT_ENTRY_VALID))
+				break; /* deleted entry, ignore it */
+			if (!(entry->type & EXFAT_ENTRY_OPTIONAL))
+			{
+				exfat_error("unknown entry type %#hhx", entry->type);
+				goto error;
+			}
+			/* optional entry, warn and skip */
+			exfat_warn("unknown entry type %#hhx", entry->type);
+			if (continuations == 0)
 			{
-				exfat_error("unknown entry type 0x%hhx", entry->type);
+				exfat_error("unexpected continuation");
 				goto error;
 			}
+			--continuations;
 			break;
 		}
 
-		if (fetch_next_entry(ef, parent, it) != 0)
+		if (!fetch_next_entry(ef, parent, it))
 			goto error;
 	}
 	/* we never reach here */
@@ -453,7 +604,7 @@ int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 	struct exfat_node* node;
 	struct exfat_node* current = NULL;
 
-	if (dir->flags & EXFAT_ATTRIB_CACHED)
+	if (dir->is_cached)
 		return 0; /* already cached */
 
 	rc = opendir(ef, dir, &it);
@@ -486,7 +637,7 @@ int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 		return rc;
 	}
 
-	dir->flags |= EXFAT_ATTRIB_CACHED;
+	dir->is_cached = true;
 	return 0;
 }
 
@@ -516,6 +667,8 @@ static void tree_detach(struct exfat_node* node)
 
 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 {
+	char buffer[EXFAT_UTF8_NAME_BUFFER_MAX];
+
 	while (node->child)
 	{
 		struct exfat_node* p = node->child;
@@ -523,14 +676,18 @@ static void reset_cache(struct exfat* ef, struct exfat_node* node)
 		tree_detach(p);
 		free(p);
 	}
-	node->flags &= ~EXFAT_ATTRIB_CACHED;
+	node->is_cached = false;
 	if (node->references != 0)
 	{
-		char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
-		exfat_get_name(node, buffer, sizeof(buffer) - 1);
-		exfat_warn("non-zero reference counter (%d) for `%s'",
+		exfat_get_name(node, buffer);
+		exfat_warn("non-zero reference counter (%d) for '%s'",
 				node->references, buffer);
 	}
+	if (node != ef->root && node->is_dirty)
+	{
+		exfat_get_name(node, buffer);
+		exfat_bug("node '%s' is dirty", buffer);
+	}
 	while (node->references)
 		exfat_put_node(ef, node);
 }
@@ -540,16 +697,24 @@ void exfat_reset_cache(struct exfat* ef)
 	reset_cache(ef, ef->root);
 }
 
-static void next_entry(struct exfat* ef, const struct exfat_node* parent,
+static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 		cluster_t* cluster, off_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);
+		if (CLUSTER_INVALID(*cluster))
+		{
+			exfat_error("invalid cluster %#x while getting next entry",
+					*cluster);
+			return false;
+		}
+	}
+	return true;
 }
 
-void exfat_flush_node(struct exfat* ef, struct exfat_node* node)
+int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 {
 	cluster_t cluster;
 	off_t offset;
@@ -557,82 +722,95 @@ void exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 	struct exfat_entry_meta1 meta1;
 	struct exfat_entry_meta2 meta2;
 
-	if (!(node->flags & EXFAT_ATTRIB_DIRTY))
-		return; /* no need to flush */
+	if (!node->is_dirty)
+		return 0; /* no need to flush */
 
 	if (ef->ro)
 		exfat_bug("unable to flush node to read-only FS");
 
 	if (node->parent == NULL)
-		return; /* do not flush unlinked node */
+		return 0; /* 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);
+	if (!next_entry(ef, node->parent, &cluster, &offset))
+		return -EIO;
 	meta2_offset = co2o(ef, cluster, offset);
 
-	/* FIXME handle I/O error */
 	if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
-		exfat_bug("failed to read meta1 entry on flush");
+	{
+		exfat_error("failed to read meta1 entry on flush");
+		return -EIO;
+	}
 	if (meta1.type != EXFAT_ENTRY_FILE)
 		exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
-	meta1.attrib = cpu_to_le16(node->flags);
+	meta1.attrib = cpu_to_le16(node->attrib);
 	exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 	exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 
-	/* FIXME handle I/O error */
 	if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
-		exfat_bug("failed to read meta2 entry on flush");
+	{
+		exfat_error("failed to read meta2 entry on flush");
+		return -EIO;
+	}
 	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.size = meta2.valid_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))
+	if (node->size != 0 && node->is_contiguous)
 		meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 	/* name hash remains unchanged, no need to recalculate it */
 
 	meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 
-	/* FIXME handle I/O error */
 	if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
-		exfat_bug("failed to write meta1 entry on flush");
-	/* FIXME handle I/O error */
+	{
+		exfat_error("failed to write meta1 entry on flush");
+		return -EIO;
+	}
 	if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
-		exfat_bug("failed to write meta2 entry on flush");
+	{
+		exfat_error("failed to write meta2 entry on flush");
+		return -EIO;
+	}
 
-	node->flags &= ~EXFAT_ATTRIB_DIRTY;
+	node->is_dirty = false;
+	return exfat_flush(ef);
 }
 
-static void erase_entry(struct exfat* ef, struct exfat_node* node)
+static int erase_entries(struct exfat* ef, struct exfat_node* dir, int n,
+		off_t offset)
 {
-	cluster_t cluster = node->entry_cluster;
-	off_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;
-	/* FIXME handle I/O error */
-	if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
-		exfat_bug("failed to erase meta1 entry");
-
-	next_entry(ef, node->parent, &cluster, &offset);
-	entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
-	/* FIXME handle I/O error */
-	if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
-		exfat_bug("failed to erase meta2 entry");
-
-	while (name_entries--)
+	struct exfat_entry entries[n];
+	int rc;
+	int i;
+
+	rc = read_entries(ef, dir, entries, n, offset);
+	if (rc != 0)
+		return rc;
+	for (i = 0; i < n; i++)
+		entries[i].type &= ~EXFAT_ENTRY_VALID;
+	return write_entries(ef, dir, entries, n, offset);
+}
+
+static int erase_node(struct exfat* ef, struct exfat_node* node)
+{
+	int rc;
+
+	exfat_get_node(node->parent);
+	rc = erase_entries(ef, node->parent, 1 + node->continuations,
+			node->entry_offset);
+	if (rc != 0)
 	{
-		next_entry(ef, node->parent, &cluster, &offset);
-		entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
-		/* FIXME handle I/O error */
-		if (exfat_pwrite(ef->dev, &entry_type, 1,
-				co2o(ef, cluster, offset)) < 0)
-			exfat_bug("failed to erase name entry");
+		exfat_put_node(ef, node->parent);
+		return rc;
 	}
+	rc = exfat_flush_node(ef, node->parent);
+	exfat_put_node(ef, node->parent);
+	return rc;
 }
 
 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
@@ -642,11 +820,10 @@ static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 	const struct exfat_node* last_node;
 	uint64_t entries = 0;
 	uint64_t new_size;
-	int rc;
 
-	if (!(dir->flags & EXFAT_ATTRIB_DIR))
+	if (!(dir->attrib & EXFAT_ATTRIB_DIR))
 		exfat_bug("attempted to shrink a file");
-	if (!(dir->flags & EXFAT_ATTRIB_CACHED))
+	if (!dir->is_cached)
 		exfat_bug("attempted to shrink uncached directory");
 
 	for (last_node = node = dir->child; node; node = node->next)
@@ -678,10 +855,7 @@ static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 		new_size = CLUSTER_SIZE(*ef->sb);
 	if (new_size == dir->size)
 		return 0;
-	rc = exfat_truncate(ef, dir, new_size, true);
-	if (rc != 0)
-		return rc;
-	return 0;
+	return exfat_truncate(ef, dir, new_size, true);
 }
 
 static int delete(struct exfat* ef, struct exfat_node* node)
@@ -691,29 +865,44 @@ static int delete(struct exfat* ef, struct exfat_node* node)
 	int rc;
 
 	exfat_get_node(parent);
-	erase_entry(ef, node);
-	exfat_update_mtime(parent);
+	rc = erase_node(ef, node);
+	if (rc != 0)
+	{
+		exfat_put_node(ef, parent);
+		return rc;
+	}
 	tree_detach(node);
 	rc = shrink_directory(ef, parent, deleted_offset);
+	node->is_unlinked = true;
+	if (rc != 0)
+	{
+		exfat_flush_node(ef, parent);
+		exfat_put_node(ef, parent);
+		return rc;
+	}
+	exfat_update_mtime(parent);
+	rc = exfat_flush_node(ef, parent);
 	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)
+	if (node->attrib & 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))
+	int rc;
+
+	if (!(node->attrib & EXFAT_ATTRIB_DIR))
 		return -ENOTDIR;
 	/* check that directory is empty */
-	exfat_cache_directory(ef, node);
+	rc = exfat_cache_directory(ef, node);
+	if (rc != 0)
+		return rc;
 	if (node->child)
 		return -ENOTEMPTY;
 	return delete(ef, node);
@@ -762,7 +951,7 @@ static int find_slot(struct exfat* ef, struct exfat_node* dir,
 				return rc;
 			}
 		}
-		if (fetch_next_entry(ef, dir, &it) != 0)
+		if (!fetch_next_entry(ef, dir, &it))
 		{
 			closedir(&it);
 			return -EIO;
@@ -772,75 +961,62 @@ static int find_slot(struct exfat* ef, struct exfat_node* dir,
 	return 0;
 }
 
-static int write_entry(struct exfat* ef, struct exfat_node* dir,
+static int commit_entry(struct exfat* ef, struct exfat_node* dir,
 		const le16_t* name, cluster_t cluster, off_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);
+	struct exfat_entry entries[2 + name_entries];
+	struct exfat_entry_meta1* meta1 = (struct exfat_entry_meta1*) &entries[0];
+	struct exfat_entry_meta2* meta2 = (struct exfat_entry_meta2*) &entries[1];
 	int i;
+	int rc;
 
-	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(entries, 0, sizeof(struct exfat_entry[2]));
 
-	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->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 */
 
-	meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
+	meta2->type = EXFAT_ENTRY_FILE_INFO;
+	meta2->flags = EXFAT_FLAG_ALWAYS1;
+	meta2->name_length = name_length;
+	meta2->name_hash = exfat_calc_name_hash(ef, name, name_length);
+	meta2->start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
+
+	meta1->checksum = exfat_calc_checksum(meta1, meta2, name);
 
-	if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
-			co2o(ef, cluster, offset)) < 0)
-	{
-		exfat_error("failed to write meta1 entry");
-		return -EIO;
-	}
-	next_entry(ef, dir, &cluster, &offset);
-	if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
-			co2o(ef, cluster, offset)) < 0)
-	{
-		exfat_error("failed to write meta2 entry");
-		return -EIO;
-	}
 	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,
-				MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
-				sizeof(le16_t));
-		next_entry(ef, dir, &cluster, &offset);
-		if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
-				co2o(ef, cluster, offset)) < 0)
-		{
-			exfat_error("failed to write name entry");
-			return -EIO;
-		}
+		struct exfat_entry_name* name_entry;
+
+		name_entry = (struct exfat_entry_name*) &entries[2 + i];
+		name_entry->type = EXFAT_ENTRY_FILE_NAME;
+		name_entry->__unknown = 0;
+		memcpy(name_entry->name, name + i * EXFAT_ENAME_MAX,
+				EXFAT_ENAME_MAX * sizeof(le16_t));
 	}
 
-	init_node_meta1(node, &meta1);
-	init_node_meta2(node, &meta2);
+	rc = write_entries(ef, dir, entries, 2 + name_entries, offset);
+	if (rc != 0)
+		return rc;
+
+	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));
+	init_node_meta1(node, meta1);
+	init_node_meta2(node, meta2);
 
 	tree_attach(dir, node);
-	exfat_update_mtime(dir);
 	return 0;
 }
 
@@ -870,7 +1046,14 @@ static int create(struct exfat* ef, const char* path, uint16_t attrib)
 		exfat_put_node(ef, dir);
 		return rc;
 	}
-	rc = write_entry(ef, dir, name, cluster, offset, attrib);
+	rc = commit_entry(ef, dir, name, cluster, offset, attrib);
+	if (rc != 0)
+	{
+		exfat_put_node(ef, dir);
+		return rc;
+	}
+	exfat_update_mtime(dir);
+	rc = exfat_flush_node(ef, dir);
 	exfat_put_node(ef, dir);
 	return rc;
 }
@@ -885,7 +1068,7 @@ 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);
+	rc = create(ef, path, EXFAT_ATTRIB_DIR);
 	if (rc != 0)
 		return rc;
 	rc = exfat_lookup(ef, &node, path);
@@ -899,6 +1082,13 @@ int exfat_mkdir(struct exfat* ef, const char* path)
 		exfat_put_node(ef, node);
 		return rc;
 	}
+	rc = exfat_flush_node(ef, node);
+	if (rc != 0)
+	{
+		delete(ef, node);
+		exfat_put_node(ef, node);
+		return rc;
+	}
 	exfat_put_node(ef, node);
 	return 0;
 }
@@ -913,6 +1103,7 @@ static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 	off_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 rc;
 	int i;
 
 	if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
@@ -921,7 +1112,8 @@ static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 		exfat_error("failed to read meta1 entry on rename");
 		return -EIO;
 	}
-	next_entry(ef, node->parent, &old_cluster, &old_offset);
+	if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
+		return -EIO;
 	if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
 			co2o(ef, old_cluster, old_offset)) < 0)
 	{
@@ -929,14 +1121,17 @@ static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 		return -EIO;
 	}
 	meta1.continuations = 1 + name_entries;
-	meta2.name_hash = exfat_calc_name_hash(ef, name);
+	meta2.name_hash = exfat_calc_name_hash(ef, name, name_length);
 	meta2.name_length = name_length;
 	meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
 
-	erase_entry(ef, node);
+	rc = erase_node(ef, node);
+	if (rc != 0)
+		return rc;
 
 	node->entry_cluster = new_cluster;
 	node->entry_offset = new_offset;
+	node->continuations = 1 + name_entries;
 
 	if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 			co2o(ef, new_cluster, new_offset)) < 0)
@@ -944,7 +1139,8 @@ static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 		exfat_error("failed to write meta1 entry on rename");
 		return -EIO;
 	}
-	next_entry(ef, dir, &new_cluster, &new_offset);
+	if (!next_entry(ef, dir, &new_cluster, &new_offset))
+		return -EIO;
 	if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 			co2o(ef, new_cluster, new_offset)) < 0)
 	{
@@ -957,7 +1153,8 @@ static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 		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);
+		if (!next_entry(ef, dir, &new_cluster, &new_offset))
+			return -EIO;
 		if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 				co2o(ef, new_cluster, new_offset)) < 0)
 		{
@@ -994,7 +1191,7 @@ int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
 	}
 
 	/* check that target is not a subdirectory of the source */
-	if (node->flags & EXFAT_ATTRIB_DIR)
+	if (node->attrib & EXFAT_ATTRIB_DIR)
 	{
 		struct exfat_node* p;
 
@@ -1014,16 +1211,16 @@ int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
 		/* remove target if it's not the same node as source */
 		if (existing != node)
 		{
-			if (existing->flags & EXFAT_ATTRIB_DIR)
+			if (existing->attrib & EXFAT_ATTRIB_DIR)
 			{
-				if (node->flags & EXFAT_ATTRIB_DIR)
+				if (node->attrib & EXFAT_ATTRIB_DIR)
 					rc = exfat_rmdir(ef, existing);
 				else
 					rc = -ENOTDIR;
 			}
 			else
 			{
-				if (!(node->flags & EXFAT_ATTRIB_DIR))
+				if (!(node->attrib & EXFAT_ATTRIB_DIR))
 					rc = exfat_unlink(ef, existing);
 				else
 					rc = -EISDIR;
@@ -1031,6 +1228,16 @@ int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
 			exfat_put_node(ef, existing);
 			if (rc != 0)
 			{
+				/* free clusters even if something went wrong; overwise they
+				   will be just lost */
+				exfat_cleanup_node(ef, existing);
+				exfat_put_node(ef, dir);
+				exfat_put_node(ef, node);
+				return rc;
+			}
+			rc = exfat_cleanup_node(ef, existing);
+			if (rc != 0)
+			{
 				exfat_put_node(ef, dir);
 				exfat_put_node(ef, node);
 				return rc;
@@ -1051,26 +1258,26 @@ int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
 	rc = rename_entry(ef, dir, node, name, cluster, offset);
 	exfat_put_node(ef, dir);
 	exfat_put_node(ef, node);
-	return 0;
+	return rc;
 }
 
 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;
+	node->is_dirty = true;
 }
 
 void exfat_update_atime(struct exfat_node* node)
 {
 	node->atime = time(NULL);
-	node->flags |= EXFAT_ATTRIB_DIRTY;
+	node->is_dirty = true;
 }
 
 void exfat_update_mtime(struct exfat_node* node)
 {
 	node->mtime = time(NULL);
-	node->flags |= EXFAT_ATTRIB_DIRTY;
+	node->is_dirty = true;
 }
 
 const char* exfat_get_label(struct exfat* ef)
@@ -1078,36 +1285,19 @@ const char* exfat_get_label(struct exfat* ef)
 	return ef->label;
 }
 
-static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
+static int find_label(struct exfat* ef, off_t* offset)
 {
-	struct iterator it;
+	struct exfat_entry entry;
 	int rc;
 
-	rc = opendir(ef, ef->root, &it);
-	if (rc != 0)
-		return rc;
-
-	for (;;)
+	for (*offset = 0; ; *offset += sizeof(entry))
 	{
-		if (it.offset >= ef->root->size)
-		{
-			closedir(&it);
-			return -ENOENT;
-		}
+		rc = read_entries(ef, ef->root, &entry, 1, *offset);
+		if (rc != 0)
+			return rc;
 
-		if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
-		{
-			*cluster = it.cluster;
-			*offset = it.offset;
-			closedir(&it);
+		if (entry.type == EXFAT_ENTRY_LABEL)
 			return 0;
-		}
-
-		if (fetch_next_entry(ef, ef->root, &it) != 0)
-		{
-			closedir(&it);
-			return -EIO;
-		}
 	}
 }
 
@@ -1120,11 +1310,11 @@ int exfat_set_label(struct exfat* ef, const char* label)
 	struct exfat_entry_label entry;
 
 	memset(label_utf16, 0, sizeof(label_utf16));
-	rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
+	rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX + 1, strlen(label));
 	if (rc != 0)
 		return rc;
 
-	rc = find_label(ef, &cluster, &offset);
+	rc = find_label(ef, &offset);
 	if (rc == -ENOENT)
 		rc = find_slot(ef, ef->root, &cluster, &offset, 1);
 	if (rc != 0)
@@ -1136,12 +1326,10 @@ int exfat_set_label(struct exfat* ef, const char* label)
 	if (entry.length == 0)
 		entry.type ^= EXFAT_ENTRY_VALID;
 
-	if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
-			co2o(ef, cluster, offset)) < 0)
-	{
-		exfat_error("failed to write label entry");
-		return -EIO;
-	}
+	rc = write_entries(ef, ef->root, (struct exfat_entry*) &entry, 1, offset);
+	if (rc != 0)
+		return rc;
+
 	strcpy(ef->label, label);
 	return 0;
 }