// retrieve file buffer from local storage
// if success == TRUE then "buf" contains "size" bytes of data
void cache_mng_retrieve_file_buf (CacheMng *cmng, fuse_ino_t ino, size_t size, off_t off,
cache_mng_on_retrieve_file_buf_cb on_retrieve_file_buf_cb, void *ctx)
{
struct _CacheContext *context;
struct _CacheEntry *entry;
context = cache_context_create (size, ctx);
context->cb.retrieve_cb = on_retrieve_file_buf_cb;
entry = g_hash_table_lookup (cmng->h_entries, GUINT_TO_POINTER (ino));
if (entry && range_contain (entry->avail_range, off, off + size)) {
int fd;
ssize_t res;
char path[PATH_MAX];
if (ino != entry->ino) {
LOG_err (CMNG_LOG, "Requested inode doesn't match hashed key!");
if (context->cb.retrieve_cb)
context->cb.retrieve_cb (NULL, 0, FALSE, context->user_ctx);
cache_context_destroy (context);
return;
}
cache_mng_file_name (cmng, path, sizeof (path), ino);
fd = open (path, O_RDONLY);
context->buf = g_malloc (size);
res = pread (fd, context->buf, size, off);
close (fd);
context->success = (res == (ssize_t) size);
if (!context->success) {
g_free (context->buf);
context->buf = NULL;
}
// move entry to the front of q_lru
g_queue_unlink (cmng->q_lru, entry->ll_lru);
g_queue_push_head_link (cmng->q_lru, entry->ll_lru);
} else {
LOG_debug (CMNG_LOG, "Entry isn't found or doesn't contain requested range: %"INO_FMT, INO ino);
}
context->ev = event_new (application_get_evbase (cmng->app), -1, 0,
cache_read_cb, context);
// fire this event at once
event_active (context->ev, 0, 0);
event_add (context->ev, NULL);
}
// store file buffer into local storage
// if success == TRUE then "buf" successfuly stored on disc
void cache_mng_store_file_buf (CacheMng *cmng, fuse_ino_t ino, size_t size, off_t off, unsigned char *buf,
cache_mng_on_store_file_buf_cb on_store_file_buf_cb, void *ctx)
{
struct _CacheContext *context;
struct _CacheEntry *entry;
ssize_t res;
int fd;
char path[PATH_MAX];
guint64 old_length, new_length;
guint64 range_size;
time_t now;
range_size = (guint64)(off + size);
// limit the number of cache checks
now = time (NULL);
if (cmng->check_time < now && now - cmng->check_time >= 10) {
// remove data until we have at least size bytes of max_size left
while (cmng->max_size < cmng->size + size && g_queue_peek_tail (cmng->q_lru)) {
entry = (struct _CacheEntry *) g_queue_peek_tail (cmng->q_lru);
cache_mng_remove_file (cmng, entry->ino);
}
cmng->check_time = now;
}
context = cache_context_create (size, ctx);
context->cb.store_cb = on_store_file_buf_cb;
cache_mng_file_name (cmng, path, sizeof (path), ino);
fd = open (path, O_WRONLY|O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fd < 0) {
LOG_err (CMNG_LOG, INO_H"Failed to create / open file for writing! Path: %s", INO_T (ino), path);
if (context->cb.store_cb)
context->cb.store_cb (FALSE, context->user_ctx);
cache_context_destroy (context);
return;
}
res = pwrite(fd, buf, size, off);
close (fd);
entry = g_hash_table_lookup (cmng->h_entries, GUINT_TO_POINTER (ino));
if (!entry) {
entry = cache_entry_create (ino);
g_queue_push_head (cmng->q_lru, entry);
entry->ll_lru = g_queue_peek_head_link (cmng->q_lru);
g_hash_table_insert (cmng->h_entries, GUINT_TO_POINTER (ino), entry);
}
old_length = range_length (entry->avail_range);
range_add (entry->avail_range, off, range_size);
new_length = range_length (entry->avail_range);
if (new_length >= old_length)
cmng->size += new_length - old_length;
else {
LOG_err (CMNG_LOG, INO_H"New length is less than the old length !: %"G_GUINT64_FORMAT" <= %"G_GUINT64_FORMAT,
INO_T (ino), new_length, old_length);
}
// update modification time
entry->modification_time = time (NULL);
context->success = (res == (ssize_t) size);
LOG_debug (CMNG_LOG, INO_H"Written [%"OFF_FMT":%zu] bytes, result: %s",
INO_T (ino), off, size, context->success ? "OK" : "Failed");
context->ev = event_new (application_get_evbase (cmng->app), -1, 0,
cache_write_cb, context);
// fire this event at once
event_active (context->ev, 0, 0);
event_add (context->ev, NULL);
}
