NFS client bugfixes and cleanups for Linux 4.5

Bugfixes:
 - pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn
 - pNFS/flexfiles: Improve merging of errors in LAYOUTRETURN
 
 Cleanups:
 - NFS: Simplify nfs_request_add_commit_list() arguments
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQIcBAABAgAGBQJWo7eYAAoJEGcL54qWCgDyqWIP/iJFYMdOGwPd6zKA4cfPryTs
 PavS96vzFMsXkr26WyibS6J/pWBSlZA4u7PMqmkR68KhPFRlKDIkaBPUskD4kZS+
 DyTzT3VCBCrDdpnZi+Hk5PfFE6j/fyIs5Im/R+TJFHpdkF3/cLr9o2nuIrm8WOI3
 e+pgcDHJNJSdMvILz9OEGT/s9zi22sqebT0KoTVa19VwisWyjQeB6p2LNAmZF1TZ
 dWRDDcBBw/f5MTnwiS5yqTFtSUnMaiMS7QmNQiX2AiN/rUvNkt6fk45K1XtCmuFV
 X9rv1rsBn1wqW5Knb90eS8OMfNYirFOZZxjuSyOP7dzUxDlWSeTLCkXvUKgKVp0A
 ycu8yckfGR7U1f+jDA87xFMwe4LaP965pprWxIRdqXPMzbDR5x2+b4kVly9TtaD0
 ZploPen9eJTcqh/tzh9RsE30n8UINBPgdh+kEZMeTaAp2mDj1Y220Y7v3s2wvb3/
 xr++FoWlW3EQ/TPEWOtRnVPVPOViZ/xsZmmTMvLfETpTYfC3hpSRWyU4dyQk1bhc
 Kw/rmGWAXU/Y7Du9TM5uExveb/mZK29hLRuhgFAOnMClZ2W6e4yflmjiGJIPw6wA
 E1YuhRUv7nv2EgM190KbDGPbVJ2e54bob9lm3JdcDwSSnqaEcr3imcqjEsEUIeMF
 431tAoroBsf8si0pIX35
 =+1hy
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-4.5-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes and cleanups from Trond Myklebust:
 "Bugfixes:
   - pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn
   - pNFS/flexfiles: Improve merging of errors in LAYOUTRETURN

  Cleanups:
   - NFS: Simplify nfs_request_add_commit_list() arguments"

* tag 'nfs-for-4.5-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn
  NFS: Simplify nfs_request_add_commit_list() arguments
  pNFS/flexfiles: Improve merging of errors in LAYOUTRETURN

fs/nfs/filelayout/filelayout.c

@@ -971,7 +971,7 @@ filelayout_mark_request_commit(struct nfs_page *req,
 	u32 i, j;
 
 	if (fl->commit_through_mds) {
-		nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
+		nfs_request_add_commit_list(req, cinfo);
 	} else {
 		/* Note that we are calling nfs4_fl_calc_j_index on each page
 		 * that ends up being committed to a data server.  An attractive

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -1948,11 +1948,9 @@ ff_layout_encode_layoutreturn(struct pnfs_layout_hdr *lo,
 	start = xdr_reserve_space(xdr, 4);
 	BUG_ON(!start);
 
-	if (ff_layout_encode_ioerr(flo, xdr, args))
+	ff_layout_encode_ioerr(flo, xdr, args);
-		goto out;
-
 	ff_layout_encode_iostats(flo, xdr, args);
-out:
+
 	*start = cpu_to_be32((xdr->p - start - 1) * 4);
 	dprintk("%s: Return\n", __func__);
 }

fs/nfs/flexfilelayout/flexfilelayoutdev.c

@@ -218,63 +218,55 @@ static void extend_ds_error(struct nfs4_ff_layout_ds_err *err,
 	err->length = end - err->offset;
 }
 
-static bool ds_error_can_merge(struct nfs4_ff_layout_ds_err *err,  u64 offset,
+static int
-			       u64 length, int status, enum nfs_opnum4 opnum,
+ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1,
-			       nfs4_stateid *stateid,
+		const struct nfs4_ff_layout_ds_err *e2)
-			       struct nfs4_deviceid *deviceid)
 {
-	return err->status == status && err->opnum == opnum &&
+	int ret;
-	       nfs4_stateid_match(&err->stateid, stateid) &&
+
-	       !memcmp(&err->deviceid, deviceid, sizeof(*deviceid)) &&
+	if (e1->opnum != e2->opnum)
-	       end_offset(err->offset, err->length) >= offset &&
+		return e1->opnum < e2->opnum ? -1 : 1;
-	       err->offset <= end_offset(offset, length);
+	if (e1->status != e2->status)
+		return e1->status < e2->status ? -1 : 1;
+	ret = memcmp(&e1->stateid, &e2->stateid, sizeof(e1->stateid));
+	if (ret != 0)
+		return ret;
+	ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid));
+	if (ret != 0)
+		return ret;
+	if (end_offset(e1->offset, e1->length) < e2->offset)
+		return -1;
+	if (e1->offset > end_offset(e2->offset, e2->length))
+		return 1;
+	/* If ranges overlap or are contiguous, they are the same */
+	return 0;
 }
 
-static bool merge_ds_error(struct nfs4_ff_layout_ds_err *old,
+static void
-			   struct nfs4_ff_layout_ds_err *new)
-{
-	if (!ds_error_can_merge(old, new->offset, new->length, new->status,
-				new->opnum, &new->stateid, &new->deviceid))
-		return false;
-
-	extend_ds_error(old, new->offset, new->length);
-	return true;
-}
-
-static bool
 ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo,
 			      struct nfs4_ff_layout_ds_err *dserr)
 {
-	struct nfs4_ff_layout_ds_err *err;
+	struct nfs4_ff_layout_ds_err *err, *tmp;
+	struct list_head *head = &flo->error_list;
+	int match;
 
-	list_for_each_entry(err, &flo->error_list, list) {
+	/* Do insertion sort w/ merges */
-		if (merge_ds_error(err, dserr)) {
+	list_for_each_entry_safe(err, tmp, &flo->error_list, list) {
-			return true;
+		match = ff_ds_error_match(err, dserr);
-		}
+		if (match < 0)
-	}
+			continue;
-
+		if (match > 0) {
-	list_add(&dserr->list, &flo->error_list);
+			/* Add entry "dserr" _before_ entry "err" */
-	return false;
+			head = &err->list;
-}
-
-static bool
-ff_layout_update_ds_error(struct nfs4_flexfile_layout *flo, u64 offset,
-			  u64 length, int status, enum nfs_opnum4 opnum,
-			  nfs4_stateid *stateid, struct nfs4_deviceid *deviceid)
-{
-	bool found = false;
-	struct nfs4_ff_layout_ds_err *err;
-
-	list_for_each_entry(err, &flo->error_list, list) {
-		if (ds_error_can_merge(err, offset, length, status, opnum,
-				       stateid, deviceid)) {
-			found = true;
-			extend_ds_error(err, offset, length);
 			break;
 		}
+		/* Entries match, so merge "err" into "dserr" */
+		extend_ds_error(dserr, err->offset, err->length);
+		list_del(&err->list);
+		kfree(err);
 	}
 
-	return found;
+	list_add_tail(&dserr->list, head);
 }
 
 int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
@@ -283,7 +275,6 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
 			     gfp_t gfp_flags)
 {
 	struct nfs4_ff_layout_ds_err *dserr;
-	bool needfree;
 
 	if (status == 0)
 		return 0;
@@ -291,14 +282,6 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
 	if (mirror->mirror_ds == NULL)
 		return -EINVAL;
 
-	spin_lock(&flo->generic_hdr.plh_inode->i_lock);
-	if (ff_layout_update_ds_error(flo, offset, length, status, opnum,
-				      &mirror->stateid,
-				      &mirror->mirror_ds->id_node.deviceid)) {
-		spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
-		return 0;
-	}
-	spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
 	dserr = kmalloc(sizeof(*dserr), gfp_flags);
 	if (!dserr)
 		return -ENOMEM;
@@ -313,10 +296,8 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
 	       NFS4_DEVICEID4_SIZE);
 
 	spin_lock(&flo->generic_hdr.plh_inode->i_lock);
-	needfree = ff_layout_add_ds_error_locked(flo, dserr);
+	ff_layout_add_ds_error_locked(flo, dserr);
 	spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
-	if (needfree)
-		kfree(dserr);
 
 	return 0;
 }

fs/nfs/internal.h

@@ -484,7 +484,7 @@ void nfs_retry_commit(struct list_head *page_list,
 		      struct nfs_commit_info *cinfo,
 		      u32 ds_commit_idx);
 void nfs_commitdata_release(struct nfs_commit_data *data);
-void nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
+void nfs_request_add_commit_list(struct nfs_page *req,
 				 struct nfs_commit_info *cinfo);
 void nfs_request_add_commit_list_locked(struct nfs_page *req,
 		struct list_head *dst,

fs/nfs/write.c

@@ -830,11 +830,10 @@ EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
  * holding the nfs_page lock.
  */
 void
-nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
+nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
-			    struct nfs_commit_info *cinfo)
 {
 	spin_lock(cinfo->lock);
-	nfs_request_add_commit_list_locked(req, dst, cinfo);
+	nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 	spin_unlock(cinfo->lock);
 	nfs_mark_page_unstable(req->wb_page, cinfo);
 }
@@ -892,7 +891,7 @@ nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 {
 	if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 		return;
-	nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
+	nfs_request_add_commit_list(req, cinfo);
 }
 
 static void