static int shrink_file(struct exfat* ef, struct exfat_node* node,
uint32_t current, uint32_t difference)
{
cluster_t previous;
cluster_t next;
if (difference == 0)
exfat_bug("zero difference passed");
if (node->start_cluster == EXFAT_CLUSTER_FREE)
exfat_bug("unable to shrink empty file (%u clusters)", current);
if (current < difference)
exfat_bug("file underflow (%u < %u)", current, difference);
/* crop the file */
if (current > difference)
{
cluster_t last = exfat_advance_cluster(ef, node,
current - difference - 1);
if (CLUSTER_INVALID(last))
{
exfat_error("invalid cluster 0x%x while shrinking", last);
return -EIO;
}
previous = exfat_next_cluster(ef, node, last);
if (!set_next_cluster(ef, IS_CONTIGUOUS(*node), last,
EXFAT_CLUSTER_END))
return -EIO;
}
else
{
previous = node->start_cluster;
node->start_cluster = EXFAT_CLUSTER_FREE;
}
node->fptr_index = 0;
node->fptr_cluster = node->start_cluster;
/* free remaining clusters */
while (difference--)
{
if (CLUSTER_INVALID(previous))
{
exfat_error("invalid cluster 0x%x while freeing after shrink",
previous);
return -EIO;
}
next = exfat_next_cluster(ef, node, previous);
if (!set_next_cluster(ef, IS_CONTIGUOUS(*node), previous,
EXFAT_CLUSTER_FREE))
return -EIO;
free_cluster(ef, previous);
previous = next;
}
return 0;
}
static int erase_range(struct exfat* ef, struct exfat_node* node,
uint64_t begin, uint64_t end)
{
uint64_t cluster_boundary;
cluster_t cluster;
if (begin >= end)
return 0;
cluster_boundary = (begin | (CLUSTER_SIZE(*ef->sb) - 1)) + 1;
cluster = exfat_advance_cluster(ef, node,
begin / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while erasing", cluster);
return -EIO;
}
/* erase from the beginning to the closest cluster boundary */
erase_raw(ef, MIN(cluster_boundary, end) - begin,
exfat_c2o(ef, cluster) + begin % CLUSTER_SIZE(*ef->sb));
/* erase whole clusters */
while (cluster_boundary < end)
{
cluster = exfat_next_cluster(ef, node, cluster);
/* the cluster cannot be invalid because we have just allocated it */
if (CLUSTER_INVALID(cluster))
exfat_bug("invalid cluster 0x%x after allocation", cluster);
erase_raw(ef, CLUSTER_SIZE(*ef->sb), exfat_c2o(ef, cluster));
cluster_boundary += CLUSTER_SIZE(*ef->sb);
}
return 0;
}
static int nodeck(struct exfat* ef, struct exfat_node* node)
{
const cluster_t cluster_size = CLUSTER_SIZE(*ef->sb);
cluster_t clusters = (node->size + cluster_size - 1) / cluster_size;
cluster_t c = node->start_cluster;
int rc = 0;
while (clusters--)
{
if (CLUSTER_INVALID(c))
{
char name[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
exfat_get_name(node, name, sizeof(name) - 1);
exfat_error("file '%s' has invalid cluster 0x%x", name, c);
rc = 1;
break;
}
if (BMAP_GET(ef->cmap.chunk, c - EXFAT_FIRST_DATA_CLUSTER) == 0)
{
char name[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
exfat_get_name(node, name, sizeof(name) - 1);
exfat_error("cluster 0x%x of file '%s' is not allocated", c, name);
rc = 1;
}
c = exfat_next_cluster(ef, node, c);
}
return rc;
}
static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
struct iterator* it)
{
/* move iterator to the next entry in the directory */
it->offset += sizeof(struct exfat_entry);
/* fetch the next cluster if needed */
if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
{
/* reached the end of directory; the caller should check this
condition too */
if (it->offset >= parent->size)
return 0;
it->cluster = exfat_next_cluster(ef, parent, it->cluster);
if (CLUSTER_INVALID(it->cluster))
{
exfat_error("invalid cluster 0x%x while reading directory",
it->cluster);
return 1;
}
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 0;
}
static uint64_t rootdir_size(const struct exfat* ef)
{
uint32_t clusters = 0;
uint32_t clusters_max = le32_to_cpu(ef->sb->cluster_count);
cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
/* Iterate all clusters of the root directory to calculate its size.
It can't be contiguous because there is no flag to indicate this. */
do
{
if (clusters == clusters_max) /* infinite loop detected */
{
exfat_error("root directory cannot occupy all %d clusters",
clusters);
return 0;
}
if (CLUSTER_INVALID(rootdir_cluster))
{
exfat_error("bad cluster %#x while reading root directory",
rootdir_cluster);
return 0;
}
rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
clusters++;
}
while (rootdir_cluster != EXFAT_CLUSTER_END);
return (uint64_t) clusters * CLUSTER_SIZE(*ef->sb);
}
static void next_entry(struct exfat* ef, const struct exfat_node* parent,
cluster_t* cluster, off64_t* offset)
{
*offset += sizeof(struct exfat_entry);
if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
/* next cluster cannot be invalid */
*cluster = exfat_next_cluster(ef, parent, *cluster);
}
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;
}
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)
{
*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;
}
ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
void* buffer, size_t size, off64_t offset)
{
cluster_t cluster;
char* bufp = buffer;
off64_t lsize, loffset, remainder;
if (offset >= node->size)
return 0;
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 reading", cluster);
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = MIN(size, node->size - offset);
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while reading", cluster);
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
if (exfat_pread(ef->dev, bufp, lsize,
exfat_c2o(ef, cluster) + loffset) < 0)
{
exfat_error("failed to read cluster %#x", cluster);
return -1;
}
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
if (!ef->ro && !ef->noatime)
exfat_update_atime(node);
return MIN(size, node->size - offset) - remainder;
}
static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
struct iterator* it)
{
/* move iterator to the next entry in the directory */
it->offset += sizeof(struct exfat_entry);
/* fetch the next cluster if needed */
if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
{
it->cluster = exfat_next_cluster(ef, parent, it->cluster);
if (CLUSTER_INVALID(it->cluster))
{
exfat_error("invalid cluster while reading directory");
return 1;
}
exfat_read_raw(it->chunk, CLUSTER_SIZE(*ef->sb),
exfat_c2o(ef, it->cluster), ef->fd);
}
return 0;
}
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;
}
cluster_t exfat_advance_cluster(const struct exfat* ef,
struct exfat_node* node, uint32_t count)
{
uint32_t i;
if (node->fptr_index > count)
{
node->fptr_index = 0;
node->fptr_cluster = node->start_cluster;
}
for (i = node->fptr_index; i < count; i++)
{
node->fptr_cluster = exfat_next_cluster(ef, node, node->fptr_cluster);
if (CLUSTER_INVALID(node->fptr_cluster))
break; /* the caller should handle this and print appropriate
error message */
}
node->fptr_index = count;
return node->fptr_cluster;
}
ssize_t exfat_read(const struct exfat* ef, struct exfat_node* node,
void* buffer, size_t size, off_t offset)
{
cluster_t cluster;
char* bufp = buffer;
off_t lsize, loffset, remainder;
if (offset >= node->size)
return 0;
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 = MIN(size, node->size - offset);
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
exfat_read_raw(bufp, lsize, exfat_c2o(ef, cluster) + loffset, ef->fd);
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
if (!ef->ro && !ef->noatime)
exfat_update_atime(node);
return size - remainder;
}
