server: send return quit when asked to leave

[fio.git] / io_u.c

diff --git a/io_u.c b/io_u.c
index a87c58e32791e35cfbb770c705a2c34c9b41ee17..77069c55277f8aeb0cd93d99754b12913cdfbaee 100644 (file)
--- a/io_u.c
+++ b/io_u.c
@@ -1120,6 +1120,44 @@ static int check_get_verify(struct thread_data *td, struct io_u *io_u)
        return 0;
 }
 
+/*
+ * Fill offset and start time into the buffer content, to prevent too
+ * easy compressible data for simple de-dupe attempts. Do this for every
+ * 512b block in the range, since that should be the smallest block size
+ * we can expect from a device.
+ */
+static void small_content_scramble(struct io_u *io_u)
+{
+       unsigned int i, nr_blocks = io_u->buflen / 512;
+       unsigned long long boffset;
+       unsigned int offset;
+       void *p, *end;
+
+       if (!nr_blocks)
+               return;
+
+       p = io_u->xfer_buf;
+       boffset = io_u->offset;
+
+       for (i = 0; i < nr_blocks; i++) {
+               /*
+                * Fill the byte offset into a "random" start offset of
+                * the buffer, given by the product of the usec time
+                * and the actual offset.
+                */
+               offset = (io_u->start_time.tv_usec ^ boffset) & 511;
+               offset &= ~(sizeof(unsigned long long) - 1);
+               if (offset >= 512 - sizeof(unsigned long long))
+                       offset -= sizeof(unsigned long long);
+               memcpy(p + offset, &boffset, sizeof(boffset));
+
+               end = p + 512 - sizeof(io_u->start_time);
+               memcpy(end, &io_u->start_time, sizeof(io_u->start_time));
+               p += 512;
+               boffset += 512;
+       }
+}
+
 /*
  * Return an io_u to be processed. Gets a buflen and offset, sets direction,
  * etc. The returned io_u is fully ready to be prepped and submitted.
@@ -1128,6 +1166,7 @@ struct io_u *get_io_u(struct thread_data *td)
 {
        struct fio_file *f;
        struct io_u *io_u;
+       int do_scramble = 0;
 
        io_u = __get_io_u(td);
        if (!io_u) {
@@ -1169,11 +1208,14 @@ struct io_u *get_io_u(struct thread_data *td)
                f->last_start = io_u->offset;
                f->last_pos = io_u->offset + io_u->buflen;
 
-               if (td->o.verify != VERIFY_NONE && io_u->ddir == DDIR_WRITE)
-                       populate_verify_io_u(td, io_u);
-               else if (td->o.refill_buffers && io_u->ddir == DDIR_WRITE)
-                       io_u_fill_buffer(td, io_u, io_u->xfer_buflen);
-               else if (io_u->ddir == DDIR_READ) {
+               if (io_u->ddir == DDIR_WRITE) {
+                       if (td->o.verify != VERIFY_NONE)
+                               populate_verify_io_u(td, io_u);
+                       else if (td->o.refill_buffers)
+                               io_u_fill_buffer(td, io_u, io_u->xfer_buflen);
+                       else if (td->o.scramble_buffers)
+                               do_scramble = 1;
+               } else if (io_u->ddir == DDIR_READ) {
                        /*
                         * Reset the buf_filled parameters so next time if the
                         * buffer is used for writes it is refilled.
@@ -1193,6 +1235,8 @@ out:
        if (!td_io_prep(td, io_u)) {
                if (!td->o.disable_slat)
                        fio_gettime(&io_u->start_time, NULL);
+               if (do_scramble)
+                       small_content_scramble(io_u);
                return io_u;
        }
 err_put: