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 = 1; /* a directory always has at leat 1 entry (EOD) */
uint64_t new_size;
struct exfat_entry eod;
off64_t eod_offset;
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 == dir->size)
return 0;
rc = exfat_truncate(ef, dir, new_size);
if (rc != 0)
return rc;
/* put EOD entry at the end of the last cluster */
memset(&eod, 0, sizeof(eod));
eod_offset = new_size - sizeof(struct exfat_entry);
if (last_node)
exfat_write_raw(&eod, sizeof(eod),
co2o(ef, last_node->entry_cluster, eod_offset), ef->fd);
else
exfat_write_raw(&eod, sizeof(eod),
co2o(ef, dir->start_cluster, eod_offset), ef->fd);
return 0;
}
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_read_raw(&meta1, sizeof(meta1), meta1_offset, ef->fd);
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_read_raw(&meta2, sizeof(meta2), meta2_offset, ef->fd);
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_write_raw(&meta1, sizeof(meta1), meta1_offset, ef->fd);
exfat_write_raw(&meta2, sizeof(meta2), meta2_offset, ef->fd);
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_write_raw(&entry_type, 1, co2o(ef, cluster, offset), ef->fd);
next_entry(ef, node->parent, &cluster, &offset);
entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
exfat_write_raw(&entry_type, 1, co2o(ef, cluster, offset), ef->fd);
while (name_entries--)
{
next_entry(ef, node->parent, &cluster, &offset);
entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
exfat_write_raw(&entry_type, 1, co2o(ef, cluster, offset), ef->fd);
}
}
ssize_t exfat_write(struct exfat* ef, struct exfat_node* node,
const void* buffer, size_t size, off_t offset)
{
cluster_t cluster;
const char* bufp = buffer;
off_t lsize, loffset, remainder;
if (offset + size > node->size)
{
int rc = exfat_truncate(ef, node, offset + size);
if (rc != 0)
return rc;
}
if (size == 0)
return 0;
cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = size;
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
exfat_write_raw(bufp, lsize, exfat_c2o(ef, cluster) + loffset, ef->fd);
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
exfat_update_mtime(node);
return size - remainder;
}
