ceph: drop support for preferred_osd pgs

This was an ill-conceived feature that has been removed from Ceph.  Do
this gracefully:

 - reject attempts to specify a preferred_osd via the ioctl
 - stop exposing this information via virtual xattrs
 - always fill in -1 for requests, in case we talk to an older server
 - don't calculate preferred_osd placements/pgids

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>

drivers/block/rbd.c

@@ -935,7 +935,6 @@ static int rbd_do_request(struct request *rq,
 	layout->fl_stripe_unit = cpu_to_le32(1 << RBD_MAX_OBJ_ORDER);
 	layout->fl_stripe_count = cpu_to_le32(1);
 	layout->fl_object_size = cpu_to_le32(1 << RBD_MAX_OBJ_ORDER);
-	layout->fl_pg_preferred = cpu_to_le32(-1);
 	layout->fl_pg_pool = cpu_to_le32(dev->poolid);
 	ceph_calc_raw_layout(osdc, layout, snapid, ofs, &len, &bno,
 				req, ops);

fs/ceph/file.c

@@ -54,7 +54,6 @@ prepare_open_request(struct super_block *sb, int flags, int create_mode)
 	req->r_fmode = ceph_flags_to_mode(flags);
 	req->r_args.open.flags = cpu_to_le32(flags);
 	req->r_args.open.mode = cpu_to_le32(create_mode);
-	req->r_args.open.preferred = cpu_to_le32(-1);
 out:
 	return req;
 }

fs/ceph/ioctl.c

@@ -26,8 +26,7 @@ static long ceph_ioctl_get_layout(struct file *file, void __user *arg)
 		l.stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
 		l.object_size = ceph_file_layout_object_size(ci->i_layout);
 		l.data_pool = le32_to_cpu(ci->i_layout.fl_pg_pool);
-		l.preferred_osd =
-			(s32)le32_to_cpu(ci->i_layout.fl_pg_preferred);
+		l.preferred_osd = (s32)-1;
 		if (copy_to_user(arg, &l, sizeof(l)))
 			return -EFAULT;
 	}
@@ -49,6 +48,10 @@ static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
 	if (copy_from_user(&l, arg, sizeof(l)))
 		return -EFAULT;
 
+	/* preferred_osd is no longer supported */
+	if (l.preferred_osd != -1)
+		return -EINVAL;
+
 	/* validate changed params against current layout */
 	err = ceph_do_getattr(file->f_dentry->d_inode, CEPH_STAT_CAP_LAYOUT);
 	if (!err) {
@@ -56,8 +59,6 @@ static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
 		nl.stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
 		nl.object_size = ceph_file_layout_object_size(ci->i_layout);
 		nl.data_pool = le32_to_cpu(ci->i_layout.fl_pg_pool);
-		nl.preferred_osd =
-				(s32)le32_to_cpu(ci->i_layout.fl_pg_preferred);
 	} else
 		return err;
 
@@ -69,8 +70,6 @@ static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
 		nl.object_size = l.object_size;
 	if (l.data_pool)
 		nl.data_pool = l.data_pool;
-	if (l.preferred_osd)
-		nl.preferred_osd = l.preferred_osd;
 
 	if ((nl.object_size & ~PAGE_MASK) ||
 	    (nl.stripe_unit & ~PAGE_MASK) ||
@@ -106,8 +105,6 @@ static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
 	req->r_args.setlayout.layout.fl_object_size =
 		cpu_to_le32(l.object_size);
 	req->r_args.setlayout.layout.fl_pg_pool = cpu_to_le32(l.data_pool);
-	req->r_args.setlayout.layout.fl_pg_preferred =
-		cpu_to_le32(l.preferred_osd);
 
 	parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
 	err = ceph_mdsc_do_request(mdsc, parent_inode, req);
@@ -171,8 +168,6 @@ static long ceph_ioctl_set_layout_policy (struct file *file, void __user *arg)
 			cpu_to_le32(l.object_size);
 	req->r_args.setlayout.layout.fl_pg_pool =
 			cpu_to_le32(l.data_pool);
-	req->r_args.setlayout.layout.fl_pg_preferred =
-			cpu_to_le32(l.preferred_osd);
 
 	err = ceph_mdsc_do_request(mdsc, inode, req);
 	ceph_mdsc_put_request(req);

fs/ceph/xattr.c

@@ -118,15 +118,6 @@ static size_t ceph_vxattrcb_file_layout(struct ceph_inode_info *ci, char *val,
 		(unsigned long long)ceph_file_layout_su(ci->i_layout),
 		(unsigned long long)ceph_file_layout_stripe_count(ci->i_layout),
 		(unsigned long long)ceph_file_layout_object_size(ci->i_layout));
-
-	if (ceph_file_layout_pg_preferred(ci->i_layout) >= 0) {
-		val += ret;
-		size -= ret;
-		ret += snprintf(val, size, "preferred_osd=%lld\n",
-			    (unsigned long long)ceph_file_layout_pg_preferred(
-				    ci->i_layout));
-	}
-
 	return ret;
 }
 

include/linux/ceph/ceph_fs.h

@@ -65,7 +65,7 @@ struct ceph_file_layout {
 	__le32 fl_object_stripe_unit;  /* UNUSED.  for per-object parity, if any */
 
 	/* object -> pg layout */
-	__le32 fl_pg_preferred; /* preferred primary for pg (-1 for none) */
+	__le32 fl_unused;       /* unused; used to be preferred primary (-1) */
 	__le32 fl_pg_pool;      /* namespace, crush ruleset, rep level */
 } __attribute__ ((packed));
 
@@ -384,7 +384,7 @@ union ceph_mds_request_args {
 		__le32 stripe_count;         /* ... */
 		__le32 object_size;
 		__le32 file_replication;
-		__le32 preferred;
+		__le32 unused;               /* used to be preferred osd */
 	} __attribute__ ((packed)) open;
 	struct {
 		__le32 flags;

include/linux/ceph/osdmap.h

@@ -65,8 +65,6 @@ struct ceph_osdmap {
 #define ceph_file_layout_cas_hash(l) ((__s32)le32_to_cpu((l).fl_cas_hash))
 #define ceph_file_layout_object_su(l) \
 	((__s32)le32_to_cpu((l).fl_object_stripe_unit))
-#define ceph_file_layout_pg_preferred(l) \
-	((__s32)le32_to_cpu((l).fl_pg_preferred))
 #define ceph_file_layout_pg_pool(l) \
 	((__s32)le32_to_cpu((l).fl_pg_pool))
 

net/ceph/osdmap.c

@@ -1000,7 +1000,6 @@ int ceph_calc_object_layout(struct ceph_object_layout *ol,
 {
 	unsigned num, num_mask;
 	struct ceph_pg pgid;
-	s32 preferred = (s32)le32_to_cpu(fl->fl_pg_preferred);
 	int poolid = le32_to_cpu(fl->fl_pg_pool);
 	struct ceph_pg_pool_info *pool;
 	unsigned ps;
@@ -1011,22 +1010,12 @@ int ceph_calc_object_layout(struct ceph_object_layout *ol,
 	if (!pool)
 		return -EIO;
 	ps = ceph_str_hash(pool->v.object_hash, oid, strlen(oid));
-	if (preferred >= 0) {
-		ps += preferred;
-		num = le32_to_cpu(pool->v.lpg_num);
-		num_mask = pool->lpg_num_mask;
-	} else {
 	num = le32_to_cpu(pool->v.pg_num);
 	num_mask = pool->pg_num_mask;
-	}
 
 	pgid.ps = cpu_to_le16(ps);
-	pgid.preferred = cpu_to_le16(preferred);
+	pgid.preferred = cpu_to_le16(-1);
 	pgid.pool = fl->fl_pg_pool;
-	if (preferred >= 0)
-		dout("calc_object_layout '%s' pgid %d.%xp%d\n", oid, poolid, ps,
-		     (int)preferred);
-	else
 	dout("calc_object_layout '%s' pgid %d.%x\n", oid, poolid, ps);
 
 	ol->ol_pgid = pgid;
@@ -1046,21 +1035,15 @@ static int *calc_pg_raw(struct ceph_osdmap *osdmap, struct ceph_pg pgid,
 	struct ceph_pg_pool_info *pool;
 	int ruleno;
 	unsigned poolid, ps, pps, t;
-	int preferred;
 
 	poolid = le32_to_cpu(pgid.pool);
 	ps = le16_to_cpu(pgid.ps);
-	preferred = (s16)le16_to_cpu(pgid.preferred);
 
 	pool = __lookup_pg_pool(&osdmap->pg_pools, poolid);
 	if (!pool)
 		return NULL;
 
 	/* pg_temp? */
-	if (preferred >= 0)
-		t = ceph_stable_mod(ps, le32_to_cpu(pool->v.lpg_num),
-				    pool->lpgp_num_mask);
-	else
 	t = ceph_stable_mod(ps, le32_to_cpu(pool->v.pg_num),
 			    pool->pgp_num_mask);
 	pgid.ps = cpu_to_le16(t);
@@ -1080,23 +1063,13 @@ static int *calc_pg_raw(struct ceph_osdmap *osdmap, struct ceph_pg pgid,
 		return NULL;
 	}
 
-	/* don't forcefeed bad device ids to crush */
-	if (preferred >= osdmap->max_osd ||
-	    preferred >= osdmap->crush->max_devices)
-		preferred = -1;
-
-	if (preferred >= 0)
-		pps = ceph_stable_mod(ps,
-				      le32_to_cpu(pool->v.lpgp_num),
-				      pool->lpgp_num_mask);
-	else
 	pps = ceph_stable_mod(ps,
 			      le32_to_cpu(pool->v.pgp_num),
 			      pool->pgp_num_mask);
 	pps += poolid;
 	*num = crush_do_rule(osdmap->crush, ruleno, pps, osds,
 			     min_t(int, pool->v.size, *num),
-			     preferred, osdmap->osd_weight);
+			     -1, osdmap->osd_weight);
 	return osds;
 }