+ if (nfs->rpc->readahead && time(NULL) - nfsfh->ra.buf_ts > NFS_RA_TIMEOUT) {
+ /* readahead cache timeout */
+ nfs_ra_invalidate(nfsfh);
+ }
+
+ if (nfs->rpc->readahead) {
+ if (offset >= nfsfh->ra.last_offset &&
+ offset - NFS_BLKSIZE <= nfsfh->ra.fh_offset + nfsfh->ra.cur_ra) {
+ if (nfs->rpc->readahead > nfsfh->ra.cur_ra) {
+ nfsfh->ra.cur_ra <<= 1;
+ }
+ } else {
+ nfsfh->ra.cur_ra = NFS_BLKSIZE;
+ }
+
+ nfsfh->ra.last_offset = offset;
+
+ if (nfsfh->ra.buf_offset <= offset &&
+ nfsfh->ra.buf_offset + nfsfh->ra.buf_count >= offset + count) {
+ /* serve request completely from cache */
+ data->buffer = malloc(count);
+ if (data->buffer == NULL) {
+ free_nfs_cb_data(data);
+ return -ENOMEM;
+ }
+ memcpy(data->buffer, nfsfh->ra.buf + (offset - nfsfh->ra.buf_offset), count);
+ data->cb(count, nfs, data->buffer, data->private_data);
+ nfsfh->ra.fh_offset = offset + count;
+ free_nfs_cb_data(data);
+ return 0;
+ }
+
+ /* align start offset to blocksize */
+ count += offset & (NFS_BLKSIZE - 1);
+ offset &= ~(NFS_BLKSIZE - 1);
+
+ /* align end offset to blocksize and add readahead */
+ count += nfsfh->ra.cur_ra - 1;
+ count &= ~(NFS_BLKSIZE - 1);
+
+ data->buffer = malloc(count);
+ if (data->buffer == NULL) {
+ free_nfs_cb_data(data);
+ return -ENOMEM;
+ }
+ data->offset = offset;
+ data->count = count;
+
+ if (nfsfh->ra.buf_count && nfsfh->ra.buf_offset <= offset &&
+ nfsfh->ra.buf_offset + nfsfh->ra.buf_count >= offset) {
+ /* serve request partially from cache */
+ size_t overlap = (nfsfh->ra.buf_offset + nfsfh->ra.buf_count) - offset;
+ if (overlap > count) count = overlap;
+ memcpy(data->buffer, nfsfh->ra.buf + (offset - nfsfh->ra.buf_offset), overlap);
+ offset += overlap;
+ count -= overlap;
+ }
+ } else {
+ data->offset = offset;
+ data->count = count;
+ }
+
+ data->max_offset = offset;
+