ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
const void* buffer, size_t size, off64_t offset)
{
cluster_t cluster;
const char* bufp = buffer;
off64_t lsize, loffset, remainder;
if (offset > node->size)
if (exfat_truncate(ef, node, offset, true) != 0)
return -1;
if (offset + size > node->size)
if (exfat_truncate(ef, node, offset + size, false) != 0)
return -1;
if (size == 0)
return 0;
cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while writing", cluster);
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = size;
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while writing", cluster);
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
if (exfat_pwrite(ef->dev, bufp, lsize,
exfat_c2o(ef, cluster) + loffset) < 0)
{
exfat_error("failed to write cluster %#x", cluster);
ef->was_dirty = true; // Leaves the volume "mounted", to force chkdsk on it.
return -1;
}
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
exfat_update_mtime(node);
return size - remainder;
}
void exfat_put_node(struct exfat* ef, struct exfat_node* node)
{
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);
}
if (node->references == 0)
{
/* FIXME handle I/O error */
if (exfat_flush_node(ef, node) != 0)
exfat_bug("node flush failed");
if (node->flags & EXFAT_ATTRIB_UNLINKED)
{
/* free all clusters and node structure itself */
exfat_truncate(ef, node, 0, true);
free(node);
}
/* FIXME handle I/O error */
if (exfat_flush(ef) != 0)
exfat_bug("flush failed");
}
}
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;
}
static int fuse_exfat_truncate(const char* path, off64_t size)
{
struct exfat_node* node;
int rc;
exfat_debug("[%s] %s, %"PRId64, __func__, path, size);
rc = exfat_lookup(&ef, &node, path);
if (rc != 0)
return rc;
rc = exfat_truncate(&ef, node, size);
exfat_put_node(&ef, node);
return rc;
}
static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
off64_t deleted_offset)
{
const struct exfat_node* node;
const struct exfat_node* last_node;
uint64_t entries = 0;
uint64_t new_size;
int rc;
if (!(dir->flags & EXFAT_ATTRIB_DIR))
exfat_bug("attempted to shrink a file");
if (!(dir->flags & EXFAT_ATTRIB_CACHED))
exfat_bug("attempted to shrink uncached directory");
for (last_node = node = dir->child; node; node = node->next)
{
if (deleted_offset < node->entry_offset)
{
/* there are other entries after the removed one, no way to shrink
this directory */
return 0;
}
if (last_node->entry_offset < node->entry_offset)
last_node = node;
}
if (last_node)
{
/* offset of the last entry */
entries += last_node->entry_offset / sizeof(struct exfat_entry);
/* two subentries with meta info */
entries += 2;
/* subentries with file name */
entries += DIV_ROUND_UP(utf16_length(last_node->name),
EXFAT_ENAME_MAX);
}
new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
if (new_size == 0) /* directory always has at least 1 cluster */
new_size = CLUSTER_SIZE(*ef->sb);
if (new_size == dir->size)
return 0;
rc = exfat_truncate(ef, dir, new_size, true);
if (rc != 0)
return rc;
return 0;
}
/**
* 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;
}
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;
}
static int fuse_exfat_truncate(const char* path, fbx_off_t size)
{
struct exfat_node* node;
int rc;
exfat_debug("[%s] %s, %"PRId64, __func__, path, size);
rc = exfat_lookup(&ef, &node, path);
if (rc != 0)
return rc;
rc = exfat_truncate(&ef, node, size, true);
if (rc != 0)
{
exfat_flush_node(&ef, node); /* ignore return code */
exfat_put_node(&ef, node);
return rc;
}
rc = exfat_flush_node(&ef, node);
exfat_put_node(&ef, node);
return rc;
}
void exfat_put_node(struct exfat* ef, struct exfat_node* node)
{
if (--node->references < 0)
{
char buffer[EXFAT_NAME_MAX + 1];
exfat_get_name(node, buffer, EXFAT_NAME_MAX);
exfat_bug("reference counter of `%s' is below zero", buffer);
}
if (node->references == 0)
{
if (node->flags & EXFAT_ATTRIB_DIRTY)
exfat_flush_node(ef, node);
if (node->flags & EXFAT_ATTRIB_UNLINKED)
{
/* free all clusters and node structure itself */
exfat_truncate(ef, node, 0);
free(node);
}
if (ef->cmap.dirty)
exfat_flush_cmap(ef);
}
}