Illumos 5960, 5925

5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=
Reviewed by: Prakash Surya <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>

References:
  https://www.illumos.org/issues/5960
  https://www.illumos.org/issues/5925
  https://github.com/illumos/illumos-gate/commit/a2cdcdd

Porting notes:
- [lib/libzfs/libzfs_sendrecv.c]
  - b8864a2 Fix gcc cast warnings
  - 325f023 Add linux kernel device support
  - 5c3f61e Increase Linux pipe buffer size on 'zfs receive'
- [module/zfs/zfs_vnops.c]
  - 3558fd7 Prototype/structure update for Linux
  - c12e3a5 Restructure zfs_readdir() to fix regressions
- [module/zfs/zvol.c]
  - Function @zvol_map_block() isn't needed in ZoL
  - 9965059 Prefetch start and end of volumes
- [module/zfs/dmu.c]
  - Fixed ISO C90 - mixed declarations and code
  - Function dmu_prefetch() 'int i' is initialized before
    the following code block (c90 vs. c99)
- [module/zfs/dbuf.c]
  - fc5bb51 Fix stack dbuf_hold_impl()
  - 9b67f60 Illumos 4757, 4913
  - 34229a2 Reduce stack usage for recursive traverse_visitbp()
- [module/zfs/dmu_send.c]
  - Fixed ISO C90 - mixed declarations and code
  - b58986e Use large stacks when available
  - 241b541 Illumos 5959 - clean up per-dataset feature count code
  - 77aef6f Use vmem_alloc() for nvlists
  - 00b4602 Add linux kernel memory support

Ported-by: kernelOfTruth [email protected]
Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 15 insertions, 13 deletions

diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index 829452b1d..edc5ea17a 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -547,6 +547,7 @@ dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 	const char *snapname;
 	uint64_t obj;
 	int err = 0;
+	dsl_dataset_t *ds;
 
 	err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
 	if (err != 0)
@@ -555,36 +556,37 @@ dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 	ASSERT(dsl_pool_config_held(dp));
 	obj = dsl_dir_phys(dd)->dd_head_dataset_obj;
 	if (obj != 0)
-		err = dsl_dataset_hold_obj(dp, obj, tag, dsp);
+		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
 	else
 		err = SET_ERROR(ENOENT);
 
 	/* we may be looking for a snapshot */
 	if (err == 0 && snapname != NULL) {
-		dsl_dataset_t *ds;
+		dsl_dataset_t *snap_ds;
 
 		if (*snapname++ != '@') {
-			dsl_dataset_rele(*dsp, tag);
+			dsl_dataset_rele(ds, tag);
 			dsl_dir_rele(dd, FTAG);
 			return (SET_ERROR(ENOENT));
 		}
 
 		dprintf("looking for snapshot '%s'\n", snapname);
-		err = dsl_dataset_snap_lookup(*dsp, snapname, &obj);
+		err = dsl_dataset_snap_lookup(ds, snapname, &obj);
 		if (err == 0)
-			err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
-		dsl_dataset_rele(*dsp, tag);
+			err = dsl_dataset_hold_obj(dp, obj, tag, &snap_ds);
+		dsl_dataset_rele(ds, tag);
 
 		if (err == 0) {
-			mutex_enter(&ds->ds_lock);
-			if (ds->ds_snapname[0] == 0)
-				(void) strlcpy(ds->ds_snapname, snapname,
-				    sizeof (ds->ds_snapname));
-			mutex_exit(&ds->ds_lock);
-			*dsp = ds;
+			mutex_enter(&snap_ds->ds_lock);
+			if (snap_ds->ds_snapname[0] == 0)
+				(void) strlcpy(snap_ds->ds_snapname, snapname,
+				    sizeof (snap_ds->ds_snapname));
+			mutex_exit(&snap_ds->ds_lock);
+			ds = snap_ds;
 		}
 	}
-
+	if (err == 0)
+		*dsp = ds;
 	dsl_dir_rele(dd, FTAG);
 	return (err);
 }