Illumos 5177 - remove dead code from dsl_scan.c

5177 remove dead code from dsl_scan.c
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Richard Elling <richard.elling@gmail.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Robert Mustacchi <rm@joyent.com>

References:
  https://www.illumos.org/issues/5177
  https://github.com/illumos/illumos-gate/commit/5f37736

Porting notes:

The local variable 'buf' was removed from dsl_scan_visitbp().
This wasn't part of the original patch but it should have been.

Ported by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2712

diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
index f22be9889188f9f42dea1c368d282fbb828b482b..5546dad5f656aabc24d5ab4c744c56c627d8baa0 100644 (file)
--- a/module/zfs/dsl_scan.c
+++ b/module/zfs/dsl_scan.c
@@ -389,13 +389,12 @@ dsl_scan_cancel(dsl_pool_t *dp)
            dsl_scan_cancel_sync, NULL, 3));
 }
 
-static void dsl_scan_visitbp(blkptr_t *bp,
-    const zbookmark_phys_t *zb, dnode_phys_t *dnp, arc_buf_t *pbuf,
-    dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
-    dmu_tx_t *tx);
+static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
+    dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
+    dmu_objset_type_t ostype, dmu_tx_t *tx);
 inline __attribute__((always_inline)) static void dsl_scan_visitdnode(
     dsl_scan_t *, dsl_dataset_t *ds, dmu_objset_type_t ostype,
-    dnode_phys_t *dnp, arc_buf_t *buf, uint64_t object, dmu_tx_t *tx);
+    dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
 
 void
 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
@@ -628,7 +627,7 @@ dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
 inline __attribute__((always_inline)) static int
 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
     dnode_phys_t *dnp, const blkptr_t *bp,
-    const zbookmark_phys_t *zb, dmu_tx_t *tx, arc_buf_t **bufp)
+    const zbookmark_phys_t *zb, dmu_tx_t *tx)
 {
        dsl_pool_t *dp = scn->scn_dp;
        int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
@@ -639,76 +638,72 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
                int i;
                blkptr_t *cbp;
                int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
+               arc_buf_t *buf;
 
-               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
+               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
                    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
                }
-               for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
-                       dsl_scan_prefetch(scn, *bufp, cbp, zb->zb_objset,
+               for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
+                       dsl_scan_prefetch(scn, buf, cbp, zb->zb_objset,
                            zb->zb_object, zb->zb_blkid * epb + i);
                }
-               for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
+               for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
                        zbookmark_phys_t czb;
 
                        SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
                            zb->zb_level - 1,
                            zb->zb_blkid * epb + i);
                        dsl_scan_visitbp(cbp, &czb, dnp,
-                           *bufp, ds, scn, ostype, tx);
-               }
-       } else if (BP_GET_TYPE(bp) == DMU_OT_USERGROUP_USED) {
-               uint32_t flags = ARC_WAIT;
-
-               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
-                   ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
-               if (err) {
-                       scn->scn_phys.scn_errors++;
-                       return (err);
+                           ds, scn, ostype, tx);
                }
+               (void) arc_buf_remove_ref(buf, &buf);
        } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
                uint32_t flags = ARC_WAIT;
                dnode_phys_t *cdnp;
                int i, j;
                int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
+               arc_buf_t *buf;
 
-               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
+               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
                    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
                }
-               for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
+               for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
                        for (j = 0; j < cdnp->dn_nblkptr; j++) {
                                blkptr_t *cbp = &cdnp->dn_blkptr[j];
-                               dsl_scan_prefetch(scn, *bufp, cbp,
+                               dsl_scan_prefetch(scn, buf, cbp,
                                    zb->zb_objset, zb->zb_blkid * epb + i, j);
                        }
                }
-               for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
+               for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
                        dsl_scan_visitdnode(scn, ds, ostype,
-                           cdnp, *bufp, zb->zb_blkid * epb + i, tx);
+                           cdnp, zb->zb_blkid * epb + i, tx);
                }
 
+               (void) arc_buf_remove_ref(buf, &buf);
        } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
                uint32_t flags = ARC_WAIT;
                objset_phys_t *osp;
+               arc_buf_t *buf;
 
-               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
+               err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
                    ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
                }
 
-               osp = (*bufp)->b_data;
+               osp = buf->b_data;
 
                dsl_scan_visitdnode(scn, ds, osp->os_type,
-                   &osp->os_meta_dnode, *bufp, DMU_META_DNODE_OBJECT, tx);
+                   &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
 
-               if (OBJSET_BUF_HAS_USERUSED(*bufp)) {
+               if (OBJSET_BUF_HAS_USERUSED(buf)) {
                        /*
                         * We also always visit user/group accounting
                         * objects, and never skip them, even if we are
@@ -716,12 +711,13 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
                         * deltas from this txg get integrated.
                         */
                        dsl_scan_visitdnode(scn, ds, osp->os_type,
-                           &osp->os_groupused_dnode, *bufp,
+                           &osp->os_groupused_dnode,
                            DMU_GROUPUSED_OBJECT, tx);
                        dsl_scan_visitdnode(scn, ds, osp->os_type,
-                           &osp->os_userused_dnode, *bufp,
+                           &osp->os_userused_dnode,
                            DMU_USERUSED_OBJECT, tx);
                }
+               (void) arc_buf_remove_ref(buf, &buf);
        }
 
        return (0);
@@ -729,7 +725,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 
 inline __attribute__((always_inline)) static void
 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
-    dmu_objset_type_t ostype, dnode_phys_t *dnp, arc_buf_t *buf,
+    dmu_objset_type_t ostype, dnode_phys_t *dnp,
     uint64_t object, dmu_tx_t *tx)
 {
        int j;
@@ -740,7 +736,7 @@ dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
                SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
                    dnp->dn_nlevels - 1, j);
                dsl_scan_visitbp(&dnp->dn_blkptr[j],
-                   &czb, dnp, buf, ds, scn, ostype, tx);
+                   &czb, dnp, ds, scn, ostype, tx);
        }
 
        if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
@@ -748,7 +744,7 @@ dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
                SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
                    0, DMU_SPILL_BLKID);
                dsl_scan_visitbp(&dnp->dn_spill,
-                   &czb, dnp, buf, ds, scn, ostype, tx);
+                   &czb, dnp, ds, scn, ostype, tx);
        }
 }
 
@@ -758,12 +754,10 @@ dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
  */
 static void
 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
-    dnode_phys_t *dnp, arc_buf_t *pbuf,
-    dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
-    dmu_tx_t *tx)
+    dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
+    dmu_objset_type_t ostype, dmu_tx_t *tx)
 {
        dsl_pool_t *dp = scn->scn_dp;
-       arc_buf_t *buf = NULL;
        blkptr_t *bp_toread;
 
        bp_toread = kmem_alloc(sizeof (blkptr_t), KM_PUSHPAGE);
@@ -789,17 +783,16 @@ dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
         * if required to debug an issue in dsl_scan_visitbp().
         *
         * dprintf_bp(bp,
-        *    "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx buf=%p bp=%p",
+        *    "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
         *    ds, ds ? ds->ds_object : 0,
         *    zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
-        *    pbuf, bp);
+        *    bp);
         */
 
        if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
                goto out;
 
-       if (dsl_scan_recurse(scn, ds, ostype, dnp, bp_toread, zb, tx,
-           &buf) != 0)
+       if (dsl_scan_recurse(scn, ds, ostype, dnp, bp_toread, zb, tx) != 0)
                goto out;
 
        /*
@@ -809,7 +802,6 @@ dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
         */
        if (ddt_class_contains(dp->dp_spa,
            scn->scn_phys.scn_ddt_class_max, bp)) {
-               ASSERT(buf == NULL);
                goto out;
        }
 
@@ -823,8 +815,6 @@ dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
        if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
                scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
        }
-       if (buf)
-               (void) arc_buf_remove_ref(buf, &buf);
 out:
        kmem_free(bp_toread, sizeof (blkptr_t));
 }
@@ -837,7 +827,7 @@ dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
 
        SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
            ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
-       dsl_scan_visitbp(bp, &zb, NULL, NULL,
+       dsl_scan_visitbp(bp, &zb, NULL,
            ds, scn, DMU_OST_NONE, tx);
 
        dprintf_ds(ds, "finished scan%s", "");