OSDN Git Service

Rename real_size to valid_size and add comment about this field.
[android-x86/external-exfat.git] / libexfat / node.c
index 8babe4f..8dd946f 100644 (file)
@@ -1,11 +1,24 @@
 /*
- *  node.c
- *  exFAT file system implementation library.
- *
- *  Created by Andrew Nayenko on 09.10.09.
- *  This software is distributed under the GNU General Public License 
- *  version 3 or any later.
- */
+       node.c (09.10.09)
+       exFAT file system implementation library.
+
+       Free exFAT implementation.
+       Copyright (C) 2010-2013  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 2 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, write to the Free Software Foundation, Inc.,
+       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
 
 #include "exfat.h"
 #include <errno.h>
@@ -31,28 +44,54 @@ 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[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
+
+       --node->references;
+       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);
+               exfat_get_name(node, buffer, sizeof(buffer) - 1);
+               exfat_bug("reference counter of '%s' is below zero", buffer);
        }
-
-       if (node->references == 0)
+       else if (node->references == 0 && node != ef->root)
        {
                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);
+                       exfat_get_name(node, buffer, sizeof(buffer) - 1);
+                       exfat_warn("dirty node '%s' with zero references", buffer);
                }
-               if (ef->cmap.dirty)
-                       exfat_flush_cmap(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->flags & EXFAT_ATTRIB_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)
+{
+       return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
+}
+
 static int opendir(struct exfat* ef, const struct exfat_node* dir,
                struct iterator* it)
 {
@@ -67,8 +106,12 @@ static int opendir(struct exfat* ef, const struct exfat_node* dir,
                exfat_error("out of memory");
                return -ENOMEM;
        }
-       exfat_read_raw(it->chunk, CLUSTER_SIZE(*ef->sb),
-                       exfat_c2o(ef, it->cluster), ef->fd);
+       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);
+               return -EIO;
+       }
        return 0;
 }
 
@@ -89,14 +132,24 @@ static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
        /* 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 while reading directory");
+                       exfat_error("invalid cluster 0x%x while reading directory",
+                                       it->cluster);
+                       return 1;
+               }
+               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;
                }
-               exfat_read_raw(it->chunk, CLUSTER_SIZE(*ef->sb),
-                               exfat_c2o(ef, it->cluster), ef->fd);
        }
        return 0;
 }
@@ -114,23 +167,66 @@ static struct exfat_node* allocate_node(void)
 }
 
 static void init_node_meta1(struct exfat_node* node,
-               const struct exfat_file* meta1)
+               const struct exfat_entry_meta1* meta1)
 {
        node->flags = le16_to_cpu(meta1->attrib);
-       node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime);
-       node->atime = exfat_exfat2unix(meta1->adate, meta1->atime);
+       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_file_info* meta2)
+               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->flag == EXFAT_FLAG_CONTIGUOUS)
+       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));
+}
+
+static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
+               uint16_t reference_checksum, uint64_t valid_size)
+{
+       char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
+
+       /*
+          Validate checksum first. If it's invalid all other fields probably
+          contain just garbage.
+       */
+       if (actual_checksum != reference_checksum)
+       {
+               exfat_get_name(node, buffer, sizeof(buffer) - 1);
+               exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
+                               actual_checksum, reference_checksum);
+               return 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, sizeof(buffer) - 1);
+               exfat_error("'%s' has valid size (%"PRIu64") greater than size "
+                               "(%"PRIu64")", buffer, valid_size, node->size);
+               return false;
+       }
+
+       return true;
+}
+
 /*
  * Reads one entry in directory at position pointed by iterator and fills
  * node structure.
@@ -138,38 +234,37 @@ static void init_node_meta2(struct exfat_node* node,
 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_file* file;
-       const struct exfat_file_info* file_info;
-       const struct exfat_file_name* file_name;
-       const struct exfat_upcase* upcase;
-       const struct exfat_bitmap* bitmap;
-       const struct exfat_label* label;
+       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 valid_size = 0;
 
        *node = NULL;
 
        for (;;)
        {
-               /* every directory (even empty one) occupies at least one cluster and
-                  must contain EOD entry */
-               entry = (const struct exfat_entry*)
-                               (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
-
-               switch (entry->type)
+               if (it->offset >= parent->size)
                {
-               case EXFAT_ENTRY_EOD:
                        if (continuations != 0)
                        {
-                               exfat_error("expected %hhu continuations before EOD",
-                                               continuations);
+                               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)
                        {
@@ -177,24 +272,33 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
                                                continuations);
                                goto error;
                        }
-                       file = (const struct exfat_file*) entry;
-                       continuations = file->continuations;
+                       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);
-                               return -EIO;
+                               goto error;
+                       }
+                       if (continuations > 1 +
+                                       DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
+                       {
+                               exfat_error("too many continuations (%hhu)", continuations);
+                               goto error;
                        }
-                       reference_checksum = le16_to_cpu(file->checksum);
-                       actual_checksum = exfat_start_checksum(file);
+                       reference_checksum = le16_to_cpu(meta1->checksum);
+                       actual_checksum = exfat_start_checksum(meta1);
                        *node = allocate_node();
                        if (*node == NULL)
-                               return -ENOMEM;
+                       {
+                               rc = -ENOMEM;
+                               goto error;
+                       }
                        /* new node has zero reference counter */
                        (*node)->entry_cluster = it->cluster;
-                       (*node)->entry_offset = it->offset % CLUSTER_SIZE(*ef->sb);
-                       init_node_meta1(*node, file);
+                       (*node)->entry_offset = it->offset;
+                       init_node_meta1(*node, meta1);
                        namep = (*node)->name;
                        break;
 
@@ -205,30 +309,28 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
                                                continuations);
                                goto error;
                        }
-                       file_info = (const struct exfat_file_info*) entry;
-                       init_node_meta2(*node, file_info);
+                       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);
-                       /* 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. */
-                       if (le64_to_cpu(file_info->real_size) != (*node)->size)
+                       valid_size = le64_to_cpu(meta2->valid_size);
+                       /* empty files must be marked as non-contiguous */
+                       if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
                        {
-                               exfat_error("real size does not equal to size "
-                                               "(%"PRIu64" != %"PRIu64")",
-                                               le64_to_cpu(file_info->real_size), (*node)->size);
+                               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)
                        {
-                               char buffer[EXFAT_NAME_MAX + 1];
-
-                               exfat_get_name(*node, buffer, EXFAT_NAME_MAX);
-                               exfat_error("directory `%s' has invalid size %"PRIu64" bytes",
-                                               buffer, (*node)->size);
+                               exfat_error("directory has invalid size %"PRIu64" bytes",
+                                               (*node)->size);
                                goto error;
                        }
                        --continuations;
@@ -240,19 +342,19 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
                                exfat_error("unexpected continuation");
                                goto error;
                        }
-                       file_name = (const struct exfat_file_name*) entry;
+                       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));
+                       memcpy(namep, file_name->name,
+                                       MIN(EXFAT_ENAME_MAX,
+                                               ((*node)->name + EXFAT_NAME_MAX - namep)) *
+                                       sizeof(le16_t));
                        namep += EXFAT_ENAME_MAX;
                        if (--continuations == 0)
                        {
-                               if (actual_checksum != reference_checksum)
-                               {
-                                       exfat_error("invalid checksum (0x%hx != 0x%hx)",
-                                                       actual_checksum, reference_checksum);
-                                       return -EIO;
-                               }
+                               if (!check_node(*node, actual_checksum, reference_checksum,
+                                               valid_size))
+                                       goto error;
                                if (fetch_next_entry(ef, parent, it) != 0)
                                        goto error;
                                return 0; /* entry completed */
@@ -262,11 +364,12 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
                case EXFAT_ENTRY_UPCASE:
                        if (ef->upcase != NULL)
                                break;
-                       upcase = (const struct exfat_upcase*) entry;
+                       upcase = (const struct exfat_entry_upcase*) entry;
                        if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
                        {
-                               exfat_error("invalid cluster in upcase table");
-                               return -EIO;
+                               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) ||
@@ -274,64 +377,86 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
                        {
                                exfat_error("bad upcase table size (%"PRIu64" bytes)",
                                                le64_to_cpu(upcase->size));
-                               return -EIO;
+                               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));
-                               return -ENOMEM;
+                               rc = -ENOMEM;
+                               goto error;
                        }
                        ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
 
-                       exfat_read_raw(ef->upcase, le64_to_cpu(upcase->size),
-                                       exfat_c2o(ef, le32_to_cpu(upcase->start_cluster)), ef->fd);
+                       if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
+                                       exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
+                       {
+                               exfat_error("failed to read upper case table "
+                                               "(%"PRIu64" bytes starting at cluster %#x)",
+                                               le64_to_cpu(upcase->size),
+                                               le32_to_cpu(upcase->start_cluster));
+                               goto error;
+                       }
                        break;
 
                case EXFAT_ENTRY_BITMAP:
-                       bitmap = (const struct exfat_bitmap*) entry;
-                       if (CLUSTER_INVALID(le32_to_cpu(bitmap->start_cluster)))
+                       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 in clusters bitmap");
-                               return -EIO;
+                               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)
+                       if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
                        {
-                               exfat_error("invalid bitmap size: %"PRIu64" (expected %u)",
-                                               le64_to_cpu(bitmap->size), (ef->cmap.size + 7) / 8);
-                               return -EIO;
+                               exfat_error("invalid clusters bitmap size: %"PRIu64
+                                               " (expected at least %u)",
+                                               le64_to_cpu(bitmap->size),
+                                               DIV_ROUND_UP(ef->cmap.size, 8));
+                               goto error;
                        }
-                       ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
                        /* 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));
+                       ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
                        if (ef->cmap.chunk == NULL)
                        {
-                               exfat_error("failed to allocate clusters map chunk "
+                               exfat_error("failed to allocate clusters bitmap chunk "
                                                "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
-                               return -ENOMEM;
+                               rc = -ENOMEM;
+                               goto error;
                        }
 
-                       exfat_read_raw(ef->cmap.chunk, le64_to_cpu(bitmap->size),
-                                       exfat_c2o(ef, ef->cmap.start_cluster), ef->fd);
+                       if (exfat_pread(ef->dev, ef->cmap.chunk,
+                                       BMAP_SIZE(ef->cmap.chunk_size),
+                                       exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
+                       {
+                               exfat_error("failed to read clusters bitmap "
+                                               "(%"PRIu64" bytes starting at cluster %#x)",
+                                               le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
+                               goto error;
+                       }
                        break;
 
                case EXFAT_ENTRY_LABEL:
-                       label = (const struct exfat_label*) entry;
+                       label = (const struct exfat_entry_label*) entry;
                        if (label->length > EXFAT_ENAME_MAX)
                        {
                                exfat_error("too long label (%hhu chars)", label->length);
-                               return -EIO;
+                               goto error;
                        }
+                       if (utf16_to_utf8(ef->label, label->name,
+                                               sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
+                               goto error;
                        break;
 
                default:
                        if (entry->type & EXFAT_ENTRY_VALID)
                        {
-                               exfat_error("unknown entry type 0x%hhu", entry->type);
+                               exfat_error("unknown entry type 0x%hhx", entry->type);
                                goto error;
                        }
                        break;
@@ -345,7 +470,7 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 error:
        free(*node);
        *node = NULL;
-       return -EIO;
+       return rc;
 }
 
 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
@@ -392,28 +517,55 @@ int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
        return 0;
 }
 
+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 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 reset_cache(struct exfat* ef, struct exfat_node* node)
 {
-       struct exfat_node* child;
-       struct exfat_node* next;
+       char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 
-       for (child = node->child; child; child = next)
+       while (node->child)
        {
-               reset_cache(ef, child);
-               next = child->next;
-               free(child);
+               struct exfat_node* p = node->child;
+               reset_cache(ef, p);
+               tree_detach(p);
+               free(p);
        }
+       node->flags &= ~EXFAT_ATTRIB_CACHED;
        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'",
+               exfat_get_name(node, buffer, sizeof(buffer) - 1);
+               exfat_warn("non-zero reference counter (%d) for '%s'",
                                node->references, buffer);
        }
-       while (node->references--)
+       if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
+       {
+               exfat_get_name(node, buffer, sizeof(buffer) - 1);
+               exfat_bug("node '%s' is dirty", buffer);
+       }
+       while (node->references)
                exfat_put_node(ef, node);
-       node->child = NULL;
-       node->flags &= ~EXFAT_ATTRIB_CACHED;
 }
 
 void exfat_reset_cache(struct exfat* ef)
@@ -421,65 +573,91 @@ void exfat_reset_cache(struct exfat* ef)
        reset_cache(ef, ef->root);
 }
 
-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)
 {
-       if (*offset + sizeof(struct exfat_entry) == CLUSTER_SIZE(*ef->sb))
+       *offset += sizeof(struct exfat_entry);
+       if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
        {
-               /* next cluster cannot be invalid */
                *cluster = exfat_next_cluster(ef, parent, *cluster);
-               *offset = 0;
+               if (CLUSTER_INVALID(*cluster))
+               {
+                       exfat_error("invalid cluster %#x while getting next entry",
+                                       *cluster);
+                       return false;
+               }
        }
-       else
-               *offset += sizeof(struct exfat_entry);
-
+       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;
        off_t meta1_offset, meta2_offset;
-       struct exfat_file meta1;
-       struct exfat_file_info meta2;
+       struct exfat_entry_meta1 meta1;
+       struct exfat_entry_meta2 meta2;
+
+       if (!(node->flags & EXFAT_ATTRIB_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 = exfat_c2o(ef, cluster) + offset;
-       next_entry(ef, node->parent, &cluster, &offset);
-       meta2_offset = exfat_c2o(ef, cluster) + offset;
+       meta1_offset = co2o(ef, cluster, offset);
+       if (!next_entry(ef, node->parent, &cluster, &offset))
+               return -EIO;
+       meta2_offset = co2o(ef, cluster, offset);
 
-       exfat_read_raw(&meta1, sizeof(meta1), meta1_offset, ef->fd);
+       if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
+       {
+               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);
-       exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime);
-       exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime);
+       exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
+       exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 
-       exfat_read_raw(&meta2, sizeof(meta2), meta2_offset, ef->fd);
+       if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
+       {
+               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);
-       /* empty files must be marked as fragmented */
+       meta2.flags = EXFAT_FLAG_ALWAYS1;
+       /* empty files must not be marked as contiguous */
        if (node->size != 0 && IS_CONTIGUOUS(*node))
-               meta2.flag = EXFAT_FLAG_CONTIGUOUS;
-       else
-               meta2.flag = EXFAT_FLAG_FRAGMENTED;
+               meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
        /* name hash remains unchanged, no need to recalculate it */
 
        meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 
-       exfat_write_raw(&meta1, sizeof(meta1), meta1_offset, ef->fd);
-       exfat_write_raw(&meta2, sizeof(meta2), meta2_offset, ef->fd);
+       if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
+       {
+               exfat_error("failed to write meta1 entry on flush");
+               return -EIO;
+       }
+       if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
+       {
+               exfat_error("failed to write meta2 entry on flush");
+               return -EIO;
+       }
 
        node->flags &= ~EXFAT_ATTRIB_DIRTY;
+       return 0;
 }
 
-static void erase_entry(struct exfat* ef, struct exfat_node* node)
+static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 {
        cluster_t cluster = node->entry_cluster;
        off_t offset = node->entry_offset;
@@ -487,55 +665,128 @@ static void erase_entry(struct exfat* ef, struct exfat_node* node)
        uint8_t entry_type;
 
        entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
-       exfat_write_raw(&entry_type, 1, exfat_c2o(ef, cluster) + offset, ef->fd);
+       if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
+       {
+               exfat_error("failed to erase meta1 entry");
+               return false;
+       }
 
-       next_entry(ef, node->parent, &cluster, &offset);
+       if (!next_entry(ef, node->parent, &cluster, &offset))
+               return false;
        entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
-       exfat_write_raw(&entry_type, 1, exfat_c2o(ef, cluster) + offset, ef->fd);
+       if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
+       {
+               exfat_error("failed to erase meta2 entry");
+               return false;
+       }
 
        while (name_entries--)
        {
-               next_entry(ef, node->parent, &cluster, &offset);
+               if (!next_entry(ef, node->parent, &cluster, &offset))
+                       return false;
                entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
-               exfat_write_raw(&entry_type, 1, exfat_c2o(ef, cluster) + offset,
-                               ef->fd);
+               if (exfat_pwrite(ef->dev, &entry_type, 1,
+                               co2o(ef, cluster, offset)) < 0)
+               {
+                       exfat_error("failed to erase name entry");
+                       return false;
+               }
        }
+       return true;
 }
 
-static void delete(struct exfat* ef, struct exfat_node* node)
+static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
+               off_t deleted_offset)
 {
-       erase_entry(ef, 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;
-       /* file clusters will be freed when node reference counter becomes 0 */
+       const struct exfat_node* node;
+       const struct exfat_node* last_node;
+       uint64_t entries = 0;
+       uint64_t new_size;
+
+       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;
+       return exfat_truncate(ef, dir, new_size, true);
+}
+
+static int delete(struct exfat* ef, struct exfat_node* node)
+{
+       struct exfat_node* parent = node->parent;
+       off_t deleted_offset = node->entry_offset;
+       int rc;
+
+       exfat_get_node(parent);
+       if (!erase_entry(ef, node))
+       {
+               exfat_put_node(ef, parent);
+               return -EIO;
+       }
+       exfat_update_mtime(parent);
+       tree_detach(node);
+       rc = shrink_directory(ef, parent, deleted_offset);
        node->flags |= EXFAT_ATTRIB_UNLINKED;
+       if (rc != 0)
+       {
+               exfat_flush_node(ef, parent);
+               exfat_put_node(ef, parent);
+               return rc;
+       }
+       rc = exfat_flush_node(ef, parent);
+       exfat_put_node(ef, parent);
+       return rc;
 }
 
 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 {
        if (node->flags & EXFAT_ATTRIB_DIR)
                return -EISDIR;
-       delete(ef, node);
-       return 0;
+       return delete(ef, node);
 }
 
 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 {
+       int rc;
+
        if (!(node->flags & 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;
-       delete(ef, node);
-       return 0;
+       return delete(ef, node);
 }
 
 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
@@ -543,19 +794,7 @@ static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 {
        return exfat_truncate(ef, dir,
                        DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
-                               * CLUSTER_SIZE(*ef->sb));
-}
-
-static void write_eod(struct exfat* ef, struct exfat_node* dir,
-               cluster_t cluster, off_t offset, int seek)
-{
-       struct exfat_entry eod;
-
-       while (seek--)
-               next_entry(ef, dir, &cluster, &offset);
-       memset(&eod, 0, sizeof(struct exfat_entry));
-       exfat_write_raw(&eod, sizeof(struct exfat_entry),
-                       exfat_c2o(ef, cluster) + offset, ef->fd);
+                               * CLUSTER_SIZE(*ef->sb), true);
 }
 
 static int find_slot(struct exfat* ef, struct exfat_node* dir,
@@ -574,29 +813,25 @@ static int find_slot(struct exfat* ef, struct exfat_node* dir,
                if (contiguous == 0)
                {
                        *cluster = it.cluster;
-                       *offset = it.offset % CLUSTER_SIZE(*ef->sb);
+                       *offset = it.offset;
                }
-               entry = (const struct exfat_entry*)
-                               (it.chunk + it.offset % CLUSTER_SIZE(*ef->sb));
-               if (entry->type == EXFAT_ENTRY_EOD)
+               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,
-                                       it.offset + sizeof(struct exfat_entry), /* actual size */
+                       rc = grow_directory(ef, dir, dir->size,
                                        (subentries - contiguous) * sizeof(struct exfat_entry));
                        if (rc != 0)
                        {
                                closedir(&it);
                                return rc;
                        }
-                       write_eod(ef, dir, *cluster, *offset, subentries - contiguous);
-                       break;
                }
-               if (entry->type & EXFAT_ENTRY_VALID)
-                       contiguous = 0;
-               else
-                       contiguous++;
-               if (contiguous == subentries)
-                       break;  /* suitable slot it found */
                if (fetch_next_entry(ef, dir, &it) != 0)
                {
                        closedir(&it);
@@ -611,8 +846,8 @@ static int write_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_file meta1;
-       struct exfat_file_info meta2;
+       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;
@@ -628,66 +863,77 @@ static int write_entry(struct exfat* ef, struct exfat_node* dir,
        meta1.type = EXFAT_ENTRY_FILE;
        meta1.continuations = 1 + name_entries;
        meta1.attrib = cpu_to_le16(attrib);
-       exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime);
+       exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
+                       &meta1.crtime_cs);
        meta1.adate = meta1.mdate = meta1.crdate;
        meta1.atime = meta1.mtime = meta1.crtime;
-       /* crtime_cs and mtime_cs contain addition to the time in centiseconds;
-          just ignore those fields because we operate with 2 sec resolution */
+       meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 
        memset(&meta2, 0, sizeof(meta2));
        meta2.type = EXFAT_ENTRY_FILE_INFO;
-       meta2.flag = EXFAT_FLAG_FRAGMENTED;
+       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_write_raw(&meta1, sizeof(meta1), exfat_c2o(ef, cluster) + offset,
-                       ef->fd);
-       next_entry(ef, dir, &cluster, &offset);
-       exfat_write_raw(&meta2, sizeof(meta2), exfat_c2o(ef, cluster) + offset,
-                       ef->fd);
+       if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
+                       co2o(ef, cluster, offset)) < 0)
+       {
+               exfat_error("failed to write meta1 entry");
+               return -EIO;
+       }
+       if (!next_entry(ef, dir, &cluster, &offset))
+               return -EIO;
+       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_file_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
+               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_write_raw(&name_entry, sizeof(name_entry),
-                               exfat_c2o(ef, cluster) + offset, ef->fd);
+                               MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
+                               sizeof(le16_t));
+               if (!next_entry(ef, dir, &cluster, &offset))
+                       return -EIO;
+               if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
+                               co2o(ef, cluster, offset)) < 0)
+               {
+                       exfat_error("failed to write name entry");
+                       return -EIO;
+               }
        }
 
        init_node_meta1(node, &meta1);
        init_node_meta2(node, &meta2);
 
-       node->parent = dir;
-       if (dir->child)
-       {
-               dir->child->prev = node;
-               node->next = dir->child;
-       }
-       dir->child = node;
-
-       dir->mtime = time(NULL);
-       dir->flags |= EXFAT_ATTRIB_DIRTY;
-
+       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;
        off_t offset = -1;
        le16_t name[EXFAT_NAME_MAX + 1];
        int rc;
 
-       /* FIXME filter name characters */
-
-       rc = exfat_split(ef, &dir, name, path);
+       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));
@@ -697,6 +943,12 @@ static int create(struct exfat* ef, const char* path, uint16_t attrib)
                return rc;
        }
        rc = write_entry(ef, dir, name, cluster, offset, attrib);
+       if (rc != 0)
+       {
+               exfat_put_node(ef, dir);
+               return rc;
+       }
+       rc = exfat_flush_node(ef, dir);
        exfat_put_node(ef, dir);
        return rc;
 }
@@ -718,7 +970,14 @@ int exfat_mkdir(struct exfat* ef, const char* path)
        if (rc != 0)
                return 0;
        /* directories always have at least one cluster */
-       rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb));
+       rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
+       if (rc != 0)
+       {
+               delete(ef, node);
+               exfat_put_node(ef, node);
+               return rc;
+       }
+       rc = exfat_flush_node(ef, node);
        if (rc != 0)
        {
                delete(ef, node);
@@ -728,3 +987,250 @@ int exfat_mkdir(struct exfat* ef, const char* path)
        exfat_put_node(ef, node);
        return 0;
 }
+
+static int rename_entry(struct exfat* ef, struct exfat_node* dir,
+               struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
+               off_t new_offset)
+{
+       struct exfat_entry_meta1 meta1;
+       struct exfat_entry_meta2 meta2;
+       cluster_t old_cluster = node->entry_cluster;
+       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 i;
+
+       if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
+                       co2o(ef, old_cluster, old_offset)) < 0)
+       {
+               exfat_error("failed to read meta1 entry on rename");
+               return -EIO;
+       }
+       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)
+       {
+               exfat_error("failed to read meta2 entry on rename");
+               return -EIO;
+       }
+       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);
+
+       if (!erase_entry(ef, node))
+               return -EIO;
+
+       node->entry_cluster = new_cluster;
+       node->entry_offset = new_offset;
+
+       if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
+                       co2o(ef, new_cluster, new_offset)) < 0)
+       {
+               exfat_error("failed to write meta1 entry on rename");
+               return -EIO;
+       }
+       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)
+       {
+               exfat_error("failed to write meta2 entry on rename");
+               return -EIO;
+       }
+
+       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));
+               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)
+               {
+                       exfat_error("failed to write name entry on rename");
+                       return -EIO;
+               }
+       }
+
+       memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
+       tree_detach(node);
+       tree_attach(dir, node);
+       return 0;
+}
+
+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;
+       off_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;
+       }
+
+       /* check that target is not a subdirectory of the source */
+       if (node->flags & EXFAT_ATTRIB_DIR)
+       {
+               struct exfat_node* p;
+
+               for (p = dir; p; p = p->parent)
+                       if (node == p)
+                       {
+                               if (existing != NULL)
+                                       exfat_put_node(ef, existing);
+                               exfat_put_node(ef, dir);
+                               exfat_put_node(ef, node);
+                               return -EINVAL;
+                       }
+       }
+
+       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;
+       }
+       rc = rename_entry(ef, dir, node, name, cluster, offset);
+       exfat_put_node(ef, dir);
+       exfat_put_node(ef, node);
+       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;
+}
+
+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, off_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;
+       off_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;
+
+       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;
+       }
+       strcpy(ef->label, label);
+       return 0;
+}