From: Andreas Dilger <andreas.dilger@intel.com>
Date: Thu, 5 Nov 2015 18:47:06 +0000 (+0000)
Subject: Revert "LU-4865 zfs: grow block size by write pattern"
X-Git-Tag: 2.7.63~8
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=refs%2Fchanges%2F53%2F17053%2F4;p=fs%2Flustre-release.git

Revert "LU-4865 zfs: grow block size by write pattern"

This reverts commit 3e4369135127b350dbc26a4a5dc94cfa46e394cf.

This has shown problems in testing and may be the cause of LU-7392.

Change-Id: I664f7f8c943d8a90f2d2a9845aea2636535d6b1e
Reviewed-on: http://review.whamcloud.com/17053
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/osd-zfs/osd_io.c b/lustre/osd-zfs/osd_io.c
index 85e8310..8299128 100644
--- a/lustre/osd-zfs/osd_io.c
+++ b/lustre/osd-zfs/osd_io.c
@@ -682,51 +682,6 @@ retry:
 	RETURN(rc);
 }
 
-/**
- * Policy to grow ZFS block size by write pattern.
- * For sequential write, it grows block size gradually until it reaches the
- * maximum blocksize the dataset can support. Otherwise, it will just use
- * the maximum block size.
- */
-static int osd_grow_blocksize(struct osd_object *obj, struct osd_thandle *oh,
-			      uint64_t start, uint64_t end)
-{
-	struct osd_device	*osd = osd_obj2dev(obj);
-	dmu_buf_impl_t		*db = (dmu_buf_impl_t *)obj->oo_db;
-	dnode_t			*dn;
-	uint32_t		 blksz;
-	int			 rc = 0;
-	ENTRY;
-
-	DB_DNODE_ENTER(db);
-	dn = DB_DNODE(db);
-
-	if (dn->dn_maxblkid > 0) /* can't change block size */
-		GOTO(out, rc);
-
-	blksz = dn->dn_datablksz;
-	if (blksz >= osd->od_max_blksz)
-		GOTO(out, rc);
-
-	/* now ZFS can support up to 16MB block size, and if the write
-	 * is sequential, it just increases the block size gradually */
-	if (start <= blksz) { /* sequential */
-		blksz = (uint32_t)min_t(uint64_t, osd->od_max_blksz, end);
-		if (!is_power_of_2(blksz))
-			blksz = size_roundup_power2(blksz);
-	} else { /* otherwise, use maximum block size */
-		blksz = osd->od_max_blksz;
-	}
-
-	if (blksz > dn->dn_datablksz)
-		rc = -dmu_object_set_blocksize(osd->od_os, dn->dn_object,
-					       blksz, 0, oh->ot_tx);
-	EXIT;
-out:
-	DB_DNODE_EXIT(db);
-	return rc;
-}
-
 static int osd_write_commit(const struct lu_env *env, struct dt_object *dt,
 			struct niobuf_local *lnb, int npages,
 			struct thandle *th)
@@ -745,14 +700,6 @@ static int osd_write_commit(const struct lu_env *env, struct dt_object *dt,
 	LASSERT(th != NULL);
 	oh = container_of0(th, struct osd_thandle, ot_super);
 
-	/* adjust block size. Assume the buffers are sorted. */
-	rc = osd_grow_blocksize(obj, oh, lnb[0].lnb_file_offset,
-				lnb[npages - 1].lnb_file_offset +
-				lnb[npages - 1].lnb_len);
-	if (rc < 0) /* ignore the error */
-		CDEBUG(D_INODE, "obj "DFID": change block size error rc=%d\n",
-		       PFID(lu_object_fid(&dt->do_lu)), rc);
-
 	for (i = 0; i < npages; i++) {
 		CDEBUG(D_INODE, "write %u bytes at %u\n",
 			(unsigned) lnb[i].lnb_len,
diff --git a/lustre/osd-zfs/osd_object.c b/lustre/osd-zfs/osd_object.c
index cc364a5..5c2d1f5 100644
--- a/lustre/osd-zfs/osd_object.c
+++ b/lustre/osd-zfs/osd_object.c
@@ -1303,11 +1303,16 @@ static dmu_buf_t *osd_mkreg(const struct lu_env *env, struct osd_object *obj,
 	if (rc)
 		return ERR_PTR(rc);
 
+	/*
+	 * XXX: This heuristic is non-optimal.  It would be better to
+	 * increase the blocksize up to osd->od_max_blksz during the write.
+	 * This is exactly how the ZPL behaves and it ensures that the right
+	 * blocksize is selected based on the file size rather than the
+	 * making broad assumptions based on the osd type.
+	 */
 	if (!lu_device_is_md(osd2lu_dev(osd))) {
-		/* uses 4K as default block size because clients write data
-		 * with page size that is 4K at minimum */
 		rc = -dmu_object_set_blocksize(osd->od_os, db->db_object,
-					       4096, 0, oh->ot_tx);
+					       osd->od_max_blksz, 0, oh->ot_tx);
 		if (unlikely(rc)) {
 			CERROR("%s: can't change blocksize: %d\n",
 			       osd->od_svname, rc);