Illumos #3498 panic in arc_read()

3498 panic in arc_read(): !refcount_is_zero(&pbuf->b_hdr->b_refcnt)
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Approved by: Richard Lowe <[email protected]>

References:
  illumos/illumos-gate@1b912ec7100c10e7243bf0879af0fe580e08c73d
  https://www.illumos.org/issues/3498

Ported-by: Brian Behlendorf <[email protected]>
Closes #1249

1 files changed, 5 insertions, 31 deletions

diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
index 297caa067..34a4f0382 100644
--- a/module/zfs/dsl_scan.c
+++ b/module/zfs/dsl_scan.c
@@ -363,24 +363,6 @@ dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
 	zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
 }
 
-int
-dsl_read(zio_t *pio, spa_t *spa, const blkptr_t *bpp, arc_buf_t *pbuf,
-    arc_done_func_t *done, void *private, int priority, int zio_flags,
-    uint32_t *arc_flags, const zbookmark_t *zb)
-{
-	return (arc_read(pio, spa, bpp, pbuf, done, private,
-	    priority, zio_flags, arc_flags, zb));
-}
-
-int
-dsl_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bpp,
-    arc_done_func_t *done, void *private, int priority, int zio_flags,
-    uint32_t *arc_flags, const zbookmark_t *zb)
-{
-	return (arc_read_nolock(pio, spa, bpp, done, private,
-	    priority, zio_flags, arc_flags, zb));
-}
-
 static uint64_t
 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
 {
@@ -551,12 +533,8 @@ dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
 
 	SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
 
-	/*
-	 * XXX need to make sure all of these arc_read() prefetches are
-	 * done before setting xlateall (similar to dsl_read())
-	 */
 	(void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
-	    buf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
+	    NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
 }
 
@@ -614,8 +592,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 		blkptr_t *cbp;
 		int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
 
-		err = arc_read_nolock(NULL, dp->dp_spa, bp,
-		    arc_getbuf_func, bufp,
+		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++;
@@ -637,8 +614,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 	} else if (BP_GET_TYPE(bp) == DMU_OT_USERGROUP_USED) {
 		uint32_t flags = ARC_WAIT;
 
-		err = arc_read_nolock(NULL, dp->dp_spa, bp,
-		    arc_getbuf_func, bufp,
+		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++;
@@ -650,8 +626,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 		int i, j;
 		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 
-		err = arc_read_nolock(NULL, dp->dp_spa, bp,
-		    arc_getbuf_func, bufp,
+		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++;
@@ -673,8 +648,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 		uint32_t flags = ARC_WAIT;
 		objset_phys_t *osp;
 
-		err = arc_read_nolock(NULL, dp->dp_spa, bp,
-		    arc_getbuf_func, bufp,
+		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++;