diff options
| -rw-r--r-- | libstore/nbd.c | 56 |
1 files changed, 40 insertions, 16 deletions
diff --git a/libstore/nbd.c b/libstore/nbd.c index c3a3ef66..9130db43 100644 --- a/libstore/nbd.c +++ b/libstore/nbd.c @@ -43,6 +43,8 @@ #define NBD_REQUEST_MAGIC (htonl (0x25609513)) #define NBD_REPLY_MAGIC (htonl (0x67446698)) +#define NBD_IO_MAX 10240 + struct nbd_startup { char magic[16]; /* NBD_INIT_MAGIC */ @@ -120,29 +122,45 @@ nbd_write (struct store *store, { magic: NBD_REQUEST_MAGIC, type: htonl (1), /* WRITE */ - from: htonll (addr << store->log2_block_size), - len: htonl (len) }; error_t err; mach_msg_type_number_t cc; - err = io_write (store->port, (char *) &req, sizeof req, -1, &cc); - if (err) - return err; - if (cc != sizeof req) - return EIO; - + addr <<= store->log2_block_size; *amount = 0; + do { - err = io_write (store->port, (char *) buf, len - *amount, -1, &cc); + size_t chunk = len < NBD_IO_MAX ? len : NBD_IO_MAX, nwrote; + req.from = htonll (addr); + req.len = htonl (chunk); + + err = io_write (store->port, (char *) &req, sizeof req, -1, &cc); + if (err) + return err; + if (cc != sizeof req) + return EIO; + + nwrote = 0; + do + { + err = io_write (store->port, (char *) buf, chunk - nwrote, -1, &cc); + if (err) + return err; + buf += cc; + nwrote += cc; + } while (nwrote < chunk); + + err = read_reply (store, req.handle); if (err) return err; - buf += cc; - *amount += cc; - } while (*amount < len); - return read_reply (store, req.handle); + addr += chunk; + *amount += chunk; + len -= chunk; + } while (len > 0); + + return 0; } static error_t @@ -154,12 +172,18 @@ nbd_read (struct store *store, { magic: NBD_REQUEST_MAGIC, type: htonl (0), /* READ */ - from: htonll (addr << store->log2_block_size), - len: htonl (amount), }; error_t err; mach_msg_type_number_t cc; + if (amount > NBD_IO_MAX) + amount = NBD_IO_MAX; + + addr <<= store->log2_block_size; + + req.from = htonll (addr); + req.len = htonl (amount); + err = io_write (store->port, (char *) &req, sizeof req, -1, &cc); if (err) return err; @@ -168,7 +192,7 @@ nbd_read (struct store *store, err = read_reply (store, req.handle); if (err == 0) - err = io_read (store->port, (char **) buf, len, (off_t) -1, amount); + err = io_read (store->port, (char **) buf, &cc, (off_t) -1, amount); return err; } |