* Changed obdecho persistent object id to 1; object id 0 is now illegal.

*  Fixed obdecho persistent object size at 1 MByte.

*  Changed test_brw data verification tests to work on a fixed 4k block
   rather than on page size to allow different page sized servers and
   clients.

diff --git a/lustre/include/linux/lustre_debug.h b/lustre/include/linux/lustre_debug.h
index 756d32e..669c0e8 100644 (file)
--- a/lustre/include/linux/lustre_debug.h
+++ b/lustre/include/linux/lustre_debug.h
@@ -48,6 +48,6 @@ int dump_rniobuf(struct niobuf_remote *rnb);
 int dump_ioo(struct obd_ioobj *nb);
 int dump_req(struct ptlrpc_request *req);
 int dump_obdo(struct obdo *oa);
-int page_debug_setup(void *addr, int len, __u64 off, __u64 id);
-int page_debug_check(char *who, void *addr, int len, __u64 off, __u64 id);
+int block_debug_setup(void *addr, int len, __u64 off, __u64 id);
+int block_debug_check(char *who, void *addr, int len, __u64 off, __u64 id);
 #endif

diff --git a/lustre/include/linux/obd_echo.h b/lustre/include/linux/obd_echo.h
index 5ff5e6c..d885579 100644 (file)
--- a/lustre/include/linux/obd_echo.h
+++ b/lustre/include/linux/obd_echo.h
@@ -13,6 +13,13 @@
 #define OBD_ECHO_DEVICENAME "obdecho"
 #define OBD_ECHO_CLIENT_DEVICENAME "echo_client"
 
+/* The persistent object (i.e. actually stores stuff!) */
+#define ECHO_PERSISTENT_OBJID    1ULL
+#define ECHO_PERSISTENT_SIZE     ((__u64)(1<<20))
+
+/* block size to use for data verification */
+#define OBD_ECHO_BLOCK_SIZE    (4<<10)
+
 struct ec_object {
         struct list_head       eco_obj_chain;
         struct obd_device     *eco_device;

diff --git a/lustre/obdclass/debug.c b/lustre/obdclass/debug.c
index 04d17b9..fa125c8 100644 (file)
--- a/lustre/obdclass/debug.c
+++ b/lustre/obdclass/debug.c
@@ -114,7 +114,7 @@ int dump_req(struct ptlrpc_request *req)
 */
 
 #define LPDS sizeof(__u64)
-int page_debug_setup(void *addr, int len, __u64 off, __u64 id)
+int block_debug_setup(void *addr, int len, __u64 off, __u64 id)
 {
         LASSERT(addr);
 
@@ -130,7 +130,7 @@ int page_debug_setup(void *addr, int len, __u64 off, __u64 id)
         return 0;
 }
 
-int page_debug_check(char *who, void *addr, int end, __u64 off, __u64 id)
+int block_debug_check(char *who, void *addr, int end, __u64 off, __u64 id)
 {
         __u64 ne_off;
         int err = 0;
@@ -171,5 +171,5 @@ EXPORT_SYMBOL(dump_rniobuf);
 EXPORT_SYMBOL(dump_ioo);
 //EXPORT_SYMBOL(dump_req);
 EXPORT_SYMBOL(dump_obdo);
-EXPORT_SYMBOL(page_debug_setup);
-EXPORT_SYMBOL(page_debug_check);
+EXPORT_SYMBOL(block_debug_setup);
+EXPORT_SYMBOL(block_debug_check);

diff --git a/lustre/obdecho/echo.c b/lustre/obdecho/echo.c
index a922517..8ac9b5a 100644 (file)
--- a/lustre/obdecho/echo.c
+++ b/lustre/obdecho/echo.c
@@ -51,8 +51,8 @@
 #define ECHO_INIT_OBJID      0x1000000000000000ULL
 #define ECHO_HANDLE_MAGIC    0xabcd0123fedc9876ULL
 
-#define ECHO_OBJECT0_NPAGES  16
-static struct page *echo_object0_pages[ECHO_OBJECT0_NPAGES];
+#define ECHO_PERSISTENT_PAGES (ECHO_PERSISTENT_SIZE/PAGE_SIZE)
+static struct page *echo_persistent_pages[ECHO_PERSISTENT_PAGES];
 
 enum {
         LPROC_ECHO_READ_BYTES = 1,
@@ -201,6 +201,62 @@ static int echo_setattr(struct obd_export *exp, struct obdo *oa,
         return 0;
 }
 
+static void
+echo_page_debug_setup(struct page *page, int rw, obd_id id,
+                      __u64 offset, int len)
+{
+        int   page_offset = offset & (PAGE_SIZE - 1);
+        char *addr        = ((char *)kmap(page)) + page_offset;
+
+        if (len % OBD_ECHO_BLOCK_SIZE != 0)
+                CERROR("Unexpected block size %d\n", len);
+
+        while (len > 0) {
+                if (rw & OBD_BRW_READ)
+                        block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
+                                          offset, id);
+                else
+                        block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
+                                          0xecc0ecc0ecc0ecc0ULL,
+                                          0xecc0ecc0ecc0ecc0ULL);
+                
+                addr   += OBD_ECHO_BLOCK_SIZE;
+                offset += OBD_ECHO_BLOCK_SIZE;
+                len    -= OBD_ECHO_BLOCK_SIZE;
+        }
+
+        kunmap(page);
+}
+
+static int
+echo_page_debug_check(struct page *page, obd_id id,
+                      __u64 offset, int len)
+{
+        int   page_offset = offset & (PAGE_SIZE - 1);
+        char *addr        = ((char *)kmap(page)) + page_offset;
+        int   rc          = 0;
+        int   rc2;
+
+        if (len % OBD_ECHO_BLOCK_SIZE != 0)
+                CERROR("Unexpected block size %d\n", len);
+
+        while (len > 0) {
+                rc2 = block_debug_check("echo", addr, OBD_ECHO_BLOCK_SIZE,
+                                        offset, id);
+
+                if (rc2 != 0 && rc == 0)
+                        rc = rc2;
+                
+                addr   += OBD_ECHO_BLOCK_SIZE;
+                offset += OBD_ECHO_BLOCK_SIZE;
+                len    -= OBD_ECHO_BLOCK_SIZE;
+        }
+
+        kunmap(page);
+
+        return (rc);
+}
+
 /* This allows us to verify that desc_private is passed unmolested */
 #define DESC_PRIV 0x10293847
 
@@ -233,16 +289,15 @@ int echo_preprw(int cmd, struct obd_export *export, struct obdo *oa,
 
         for (i = 0; i < objcount; i++, obj++) {
                 int gfp_mask = (obj->ioo_id & 1) ? GFP_HIGHUSER : GFP_KERNEL;
-                int isobj0 = obj->ioo_id == 0;
-                int verify = !isobj0;
+                int ispersistent = obj->ioo_id == ECHO_PERSISTENT_OBJID;
                 int j;
 
                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, nb++, r++) {
 
-                        if (isobj0 &&
-                            (nb->offset >> PAGE_SHIFT) < ECHO_OBJECT0_NPAGES) {
-                                r->page = echo_object0_pages[nb->offset >>
-                                                             PAGE_SHIFT];
+                        if (ispersistent &&
+                            (nb->offset >> PAGE_SHIFT) < ECHO_PERSISTENT_PAGES) {
+                                r->page = echo_persistent_pages[nb->offset >>
+                                                                PAGE_SHIFT];
                                 /* Take extra ref so __free_pages() can be called OK */
                                 get_page (r->page);
                         } else {
@@ -266,22 +321,12 @@ int echo_preprw(int cmd, struct obd_export *export, struct obdo *oa,
                         CDEBUG(D_PAGE, "$$$$ get page %p @ "LPU64" for %d\n",
                                r->page, r->offset, r->len);
 
-                        if (cmd & OBD_BRW_READ) {
-                                r->rc = r->len;
-                                if (verify) {
-                                        page_debug_setup(kmap (r->page), r->len,
-                                                         r->offset,obj->ioo_id);
-                                        kunmap (r->page);
-                                }
+                        if (cmd & OBD_BRW_READ)
                                 r->rc = r->len;
-                        } else {
-                                if (verify) {
-                                        page_debug_setup(kmap (r->page), r->len,
-                                                         0xecc0ecc0ecc0ecc0ULL,
-                                                         0xecc0ecc0ecc0ecc0ULL);
-                                        kunmap (r->page);
-                                }
-                        }
+
+                        if (!ispersistent)
+                                echo_page_debug_setup(r->page, cmd, obj->ioo_id,
+                                                      r->offset, r->len);
                 }
         }
         if (cmd & OBD_BRW_READ)
@@ -305,7 +350,7 @@ preprw_cleanup:
         CERROR("cleaning up %ld pages (%d obdos)\n", (long)(r - res), objcount);
         while (r-- > res) {
                 kunmap(r->page);
-                /* NB if this is an 'object0' page, __free_pages will just
+                /* NB if this is a persistent page, __free_pages will just
                  * lose the extra ref gained above */
                 __free_pages(r->page, 0);
                 atomic_dec(&obd->u.echo.eo_prep);
@@ -344,7 +389,7 @@ int echo_commitrw(int cmd, struct obd_export *export, struct obdo *oa,
         LASSERT(oti == NULL || oti->oti_handle == (void *)DESC_PRIV);
 
         for (i = 0; i < objcount; i++, obj++) {
-                int verify = obj->ioo_id != 0;
+                int verify = obj->ioo_id != ECHO_PERSISTENT_OBJID;
                 int j;
 
                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, r++) {
@@ -363,15 +408,15 @@ int echo_commitrw(int cmd, struct obd_export *export, struct obdo *oa,
                                r->page, addr, r->offset);
 
                         if (verify) {
-                                vrc = page_debug_check("echo", addr, r->len,
-                                                       r->offset, obj->ioo_id);
+                                vrc = echo_page_debug_check(page, obj->ioo_id, 
+                                                            r->offset, r->len);
                                 /* check all the pages always */
                                 if (vrc != 0 && rc == 0)
                                         rc = vrc;
                         }
 
                         kunmap(page);
-                        /* NB see comment above regarding object0 pages */
+                        /* NB see comment above regarding persistent pages */
                         __free_pages(page, 0);
                         atomic_dec(&obd->u.echo.eo_prep);
                 }
@@ -386,7 +431,7 @@ commitrw_cleanup:
         while (++r < res + niocount) {
                 struct page *page = r->page;
 
-                /* NB see comment above regarding object0 pages */
+                /* NB see comment above regarding persistent pages */
                 __free_pages(page, 0);
                 atomic_dec(&obd->u.echo.eo_prep);
         }
@@ -473,37 +518,37 @@ extern int echo_client_init(void);
 extern void echo_client_exit(void);
 
 static void
-echo_object0_pages_fini (void)
+echo_persistent_pages_fini (void)
 {
         int     i;
 
-        for (i = 0; i < ECHO_OBJECT0_NPAGES; i++)
-                if (echo_object0_pages[i] != NULL) {
-                        __free_pages (echo_object0_pages[i], 0);
-                        echo_object0_pages[i] = NULL;
+        for (i = 0; i < ECHO_PERSISTENT_PAGES; i++)
+                if (echo_persistent_pages[i] != NULL) {
+                        __free_pages (echo_persistent_pages[i], 0);
+                        echo_persistent_pages[i] = NULL;
                 }
 }
 
 static int
-echo_object0_pages_init (void)
+echo_persistent_pages_init (void)
 {
         struct page *pg;
         int          i;
 
-        for (i = 0; i < ECHO_OBJECT0_NPAGES; i++) {
-                int gfp_mask = (i < ECHO_OBJECT0_NPAGES/2) ?
+        for (i = 0; i < ECHO_PERSISTENT_PAGES; i++) {
+                int gfp_mask = (i < ECHO_PERSISTENT_PAGES/2) ?
                         GFP_KERNEL : GFP_HIGHUSER;
 
                 pg = alloc_pages (gfp_mask, 0);
                 if (pg == NULL) {
-                        echo_object0_pages_fini ();
+                        echo_persistent_pages_fini ();
                         return (-ENOMEM);
                 }
 
                 memset (kmap (pg), 0, PAGE_SIZE);
                 kunmap (pg);
 
-                echo_object0_pages[i] = pg;
+                echo_persistent_pages[i] = pg;
         }
 
         return (0);
@@ -516,9 +561,11 @@ static int __init obdecho_init(void)
 
         printk(KERN_INFO "Lustre: Echo OBD driver; info@clusterfs.com\n");
 
+        LASSERT(PAGE_SIZE % OBD_ECHO_BLOCK_SIZE == 0);
+
         lprocfs_init_vars(echo, &lvars);
 
-        rc = echo_object0_pages_init ();
+        rc = echo_persistent_pages_init ();
         if (rc != 0)
                 goto failed_0;
 
@@ -533,7 +580,7 @@ static int __init obdecho_init(void)
 
         class_unregister_type(OBD_ECHO_DEVICENAME);
  failed_1:
-        echo_object0_pages_fini ();
+        echo_persistent_pages_fini ();
  failed_0:
         RETURN(rc);
 }
@@ -542,7 +589,7 @@ static void /*__exit*/ obdecho_exit(void)
 {
         echo_client_exit();
         class_unregister_type(OBD_ECHO_DEVICENAME);
-        echo_object0_pages_fini ();
+        echo_persistent_pages_fini ();
 }
 
 MODULE_AUTHOR("Cluster File Systems, Inc. <info@clusterfs.com>");

diff --git a/lustre/obdecho/echo_client.c b/lustre/obdecho/echo_client.c
index 69862b7..f5bcf79 100644 (file)
--- a/lustre/obdecho/echo_client.c
+++ b/lustre/obdecho/echo_client.c
@@ -274,7 +274,8 @@ echo_get_object (struct ec_object **ecop, struct obd_device *obd,
         struct ec_object       *eco2;
         int                     rc;
 
-        if ((oa->o_valid & OBD_MD_FLID) == 0)
+        if ((oa->o_valid & OBD_MD_FLID) == 0 ||
+            oa->o_id == 0)                      /* disallow use of object id 0 */
         {
                 CERROR ("No valid oid\n");
                 return (-EINVAL);
@@ -423,47 +424,66 @@ echo_get_stripe_off_id (struct lov_stripe_md *lsm, obd_off *offp, obd_id *idp)
         *offp = offset * stripe_size + woffset % stripe_size;
 }
 
-static void echo_page_debug_setup(struct lov_stripe_md *lsm, 
-                                  struct page *page, int rw, obd_id id, 
-                                  obd_off offset, obd_off count)
+static void 
+echo_client_page_debug_setup(struct lov_stripe_md *lsm, 
+                             struct page *page, int rw, obd_id id, 
+                             obd_off offset, obd_off count)
 {
-        void *addr;
-        obd_off stripe_off;
-        obd_id stripe_id;
+        char    *addr;
+        obd_off  stripe_off;
+        obd_id   stripe_id;
+        int      delta;
 
-        if (id == 0)
-                return;
+        /* no partial pages on the client */
+        LASSERT(count == PAGE_SIZE);
 
         addr = kmap(page);
 
-        if (rw == OBD_BRW_WRITE) {
-                stripe_off = offset;
-                stripe_id = id;
-                echo_get_stripe_off_id(lsm, &stripe_off, &stripe_id);
-        } else {
-                stripe_off = 0xdeadbeef00c0ffeeULL;
-                stripe_id = 0xdeadbeef00c0ffeeULL;
+        for (delta = 0; delta < PAGE_SIZE; delta += OBD_ECHO_BLOCK_SIZE) {
+                if (rw == OBD_BRW_WRITE) {
+                        stripe_off = offset + delta;
+                        stripe_id = id;
+                        echo_get_stripe_off_id(lsm, &stripe_off, &stripe_id);
+                } else {
+                        stripe_off = 0xdeadbeef00c0ffeeULL;
+                        stripe_id = 0xdeadbeef00c0ffeeULL;
+                }
+                block_debug_setup(addr + delta, OBD_ECHO_BLOCK_SIZE, 
+                                  stripe_off, stripe_id);
         }
-        page_debug_setup(addr, count, stripe_off, stripe_id);
 
         kunmap(page);
 }
 
-static int echo_page_debug_check(struct lov_stripe_md *lsm, 
-                                  struct page *page, obd_id id, 
-                                  obd_off offset, obd_off count)
+static int
+echo_client_page_debug_check(struct lov_stripe_md *lsm, 
+                             struct page *page, obd_id id, 
+                             obd_off offset, obd_off count)
 {
-        obd_off stripe_off = offset;
-        obd_id stripe_id = id;
-        void *addr;
-        int rc;
+        obd_off stripe_off;
+        obd_id  stripe_id;
+        char   *addr;
+        int     delta;
+        int     rc;
+        int     rc2;
 
-        if (id == 0)
-                return 0;
+        /* no partial pages on the client */
+        LASSERT(count == PAGE_SIZE);
 
         addr = kmap(page);
-        echo_get_stripe_off_id (lsm, &stripe_off, &stripe_id);
-        rc = page_debug_check("test_brw", addr, count, stripe_off, stripe_id);
+
+        for (rc = delta = 0; delta < PAGE_SIZE; delta += OBD_ECHO_BLOCK_SIZE) {
+                stripe_off = offset + delta;
+                stripe_id = id;
+                echo_get_stripe_off_id (lsm, &stripe_off, &stripe_id);
+
+                rc2 = block_debug_check("test_brw", 
+                                        addr + delta, OBD_ECHO_BLOCK_SIZE, 
+                                        stripe_off, stripe_id);
+                if (rc2 != 0)
+                        rc = rc2;
+        }
+
         kunmap(page);
         return rc;
 }
@@ -482,10 +502,11 @@ static int echo_client_kbrw(struct obd_device *obd, int rw, struct obdo *oa,
         int                     verify = 0;
         int                     gfp_mask;
 
-        /* oa_id  == 0    => speed test (no verification) else...
-         * oa & 1         => use HIGHMEM
-         */
-        gfp_mask = ((oa->o_id & 1) == 0) ? GFP_KERNEL : GFP_HIGHUSER;
+        /* oa_id == ECHO_PERSISTENT_OBJID => speed test (no verification).
+         * oa & 1                         => use HIGHMEM */
+
+        verify = (oa->o_id) != ECHO_PERSISTENT_OBJID;
+        gfp_mask = ((oa->o_id & 2) == 0) ? GFP_KERNEL : GFP_HIGHUSER;
 
         LASSERT(rw == OBD_BRW_WRITE || rw == OBD_BRW_READ);
 
@@ -517,15 +538,16 @@ static int echo_client_kbrw(struct obd_device *obd, int rw, struct obdo *oa,
                 pgp->off = off;
                 pgp->flag = 0;
 
-                echo_page_debug_setup(lsm, pgp->pg, rw, oa->o_id, off, 
-                                      pgp->count);
+                if (verify)
+                        echo_client_page_debug_setup(lsm, pgp->pg, rw, 
+                                                     oa->o_id, off, pgp->count);
         }
 
         rc = obd_brw(rw, ec->ec_exp, oa, lsm, npages, pga, oti);
 
  out:
-        if (rc == 0 && rw == OBD_BRW_READ)
-                verify = 1;
+        if (rc != 0 || rw != OBD_BRW_READ)
+                verify = 0;
 
         for (i = 0, pgp = pga; i < npages; i++, pgp++) {
                 if (pgp->pg == NULL)
@@ -533,8 +555,8 @@ static int echo_client_kbrw(struct obd_device *obd, int rw, struct obdo *oa,
 
                 if (verify) {
                         int vrc;
-                        vrc = echo_page_debug_check(lsm, pgp->pg, oa->o_id,
-                                                    pgp->off, pgp->count);
+                        vrc = echo_client_page_debug_check(lsm, pgp->pg, oa->o_id,
+                                                           pgp->off, pgp->count);
                         if (vrc != 0 && rc == 0)
                                 rc = vrc;
                 }
@@ -698,10 +720,11 @@ static void ec_ap_completion(void *data, int cmd, int rc)
                 return;
         eas = eap->eap_eas;
 
-        if (cmd == OBD_BRW_READ)
-                echo_page_debug_check(eas->eas_lsm, eap->eap_page, 
-                                      eas->eas_oa.o_id, eap->eap_off, 
-                                      PAGE_SIZE);
+        if (cmd == OBD_BRW_READ &&
+            eas->eas_oa.o_id != ECHO_PERSISTENT_OBJID)
+                echo_client_page_debug_check(eas->eas_lsm, eap->eap_page, 
+                                             eas->eas_oa.o_id, eap->eap_off,
+                                             PAGE_SIZE);
 
         spin_lock_irqsave(&eas->eas_lock, flags);
         if (rc && !eas->eas_rc)
@@ -823,9 +846,10 @@ static int echo_client_async_page(struct obd_export *exp, int rw,
                         break;
                 }
 
-                if (rw == OBD_BRW_WRITE)
-                        echo_page_debug_setup(lsm, eap->eap_page, rw, oa->o_id,
-                                              eap->eap_off, PAGE_SIZE);
+                if (oa->o_id != ECHO_PERSISTENT_OBJID)
+                        echo_client_page_debug_setup(lsm, eap->eap_page, rw, 
+                                                     oa->o_id, 
+                                                     eap->eap_off, PAGE_SIZE);
 
                 /* always asserts urgent, which isn't quite right */
                 rc = obd_queue_async_io(exp, lsm, NULL, eap->eap_cookie,
@@ -925,14 +949,19 @@ static int echo_client_prep_commit(struct obd_export *exp, int rw,
                         if (page == NULL && lnb[i].rc == 0) 
                                 continue;
 
+                        if (oa->o_id == ECHO_PERSISTENT_OBJID)
+                                continue;
+
                         if (rw == OBD_BRW_WRITE) 
-                                echo_page_debug_setup(lsm, page, rw, oa->o_id, 
-                                                      rnb[i].offset, 
-                                                      rnb[i].len);
+                                echo_client_page_debug_setup(lsm, page, rw, 
+                                                             oa->o_id, 
+                                                             rnb[i].offset, 
+                                                             rnb[i].len);
                         else
-                                echo_page_debug_check(lsm, page, oa->o_id, 
-                                                      rnb[i].offset, 
-                                                      rnb[i].len);
+                                echo_client_page_debug_check(lsm, page, 
+                                                             oa->o_id, 
+                                                             rnb[i].offset, 
+                                                             rnb[i].len);
                 }
 
                 ret = obd_commitrw(rw, exp, oa, 1, &ioo, npages, lnb, oti);

diff --git a/lustre/tests/test_brw.c b/lustre/tests/test_brw.c
index f242eba..54126a0 100644 (file)
--- a/lustre/tests/test_brw.c
+++ b/lustre/tests/test_brw.c
@@ -31,7 +31,7 @@
 #define WRITE 2
 
 #define LPDS sizeof(__u64)
-int page_debug_setup(void *addr, int len, __u64 off, __u64 id)
+int block_debug_setup(void *addr, int len, __u64 off, __u64 id)
 {
         off = cpu_to_le64(off);
         id = cpu_to_le64(id);
@@ -45,7 +45,7 @@ int page_debug_setup(void *addr, int len, __u64 off, __u64 id)
         return 0;
 }
 
-int page_debug_check(char *who, void *addr, int size, __u64 off, __u64 id)
+int block_debug_check(char *who, void *addr, int size, __u64 off, __u64 id)
 {
         __u64 ne_off;
         int err = 0;
@@ -181,14 +181,14 @@ int main(int argc, char **argv)
                 int i;
 
                 for (i = 0; i < len; i += st.st_blksize)
-                        page_debug_setup(buf + i, st.st_blksize, offset + i,
-                                         objid);
+                        block_debug_setup(buf + i, st.st_blksize, 
+                                          offset + i, objid);
 
                 rc = write(fd, buf, len);
 
                 for (i = 0; i < len; i += st.st_blksize) {
-                        if (page_debug_check("write", buf + i, st.st_blksize,
-                                             offset + i, objid))
+                        if (block_debug_check("write", buf + i, st.st_blksize,
+                                              offset + i, objid))
                                 return 10;
                 }
 
@@ -216,8 +216,8 @@ int main(int argc, char **argv)
                 }
 
                 for (i = 0; i < len; i += st.st_blksize) {
-                        if (page_debug_check("read", buf + i, st.st_blksize,
-                                             offset + i, objid))
+                        if (block_debug_check("read", buf + i, st.st_blksize,
+                                              offset + i, objid))
                                 return 11;
                 }
         }

diff --git a/lustre/utils/obd.c b/lustre/utils/obd.c
index ad043aa..e4ef0a8 100644 (file)
--- a/lustre/utils/obd.c
+++ b/lustre/utils/obd.c
@@ -1242,6 +1242,7 @@ int jt_obd_test_brw(int argc, char **argv)
         struct timeval start, next_time;
         __u64 count, next_count, len, thr_offset = 0, objid = 3;
         int write = 0, verbose = 1, cmd, i, rc = 0, pages = 1;
+        int repeat_offset = 0;
         char *end;
 
         if (argc < 2 || argc > 7) {
@@ -1267,8 +1268,11 @@ int jt_obd_test_brw(int argc, char **argv)
         if (argc >= 3) {
                 if (argv[2][0] == 'w' || argv[2][0] == '1')
                         write = 1;
-                else if (argv[2][0] == 'r' || argv[2][0] == '0')
-                        write = 0;
+                /* else it's a read */
+
+                if (argv[2][0] != 0 &&
+                    argv[2][1] == 'r')
+                        repeat_offset = 1;
         }
 
         if (argc >= 4) {
@@ -1366,7 +1370,8 @@ int jt_obd_test_brw(int argc, char **argv)
                         printf("%s: %s number %dx%d\n", jt_cmdname(argv[0]),
                                write ? "write" : "read", i, pages);
 
-                data.ioc_offset += len;
+                if (!repeat_offset)
+                        data.ioc_offset += len;
         }
 
         if (!rc) {