svn commit: r340184 - stable/10/sys/fs/nfsserver

[Andriy Gapon]

Author: avg
Date: Tue Nov  6 14:22:44 2018
New Revision: 340184
URL: https://svnweb.freebsd.org/changeset/base/340184

Log:
  MFC r339595: nfsrvd_readdirplus: for some errors, do not fail the entire request
  
  Sponsored by:	Panzura

Modified:
  stable/10/sys/fs/nfsserver/nfs_nfsdport.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/fs/nfsserver/nfs_nfsdport.c
==============================================================================
--- stable/10/sys/fs/nfsserver/nfs_nfsdport.c	Tue Nov  6 14:21:26 2018	(r340183)
+++ stable/10/sys/fs/nfsserver/nfs_nfsdport.c	Tue Nov  6 14:22:44 2018	(r340184)
@@ -2145,10 +2145,22 @@ again:
 						}
 					}
 				}
-				if (!r) {
-				    if (refp == NULL &&
-					((nd->nd_flag & ND_NFSV3) ||
-					 NFSNONZERO_ATTRBIT(&attrbits))) {
+
+				/*
+				 * If we failed to look up the entry, then it
+				 * has become invalid, most likely removed.
+				 */
+				if (r != 0) {
+					if (needs_unbusy)
+						vfs_unbusy(new_mp);
+					goto invalid;
+				}
+				KASSERT(refp != NULL || nvp != NULL,
+				    ("%s: undetected lookup error", __func__));
+
+				if (refp == NULL &&
+				    ((nd->nd_flag & ND_NFSV3) ||
+				     NFSNONZERO_ATTRBIT(&attrbits))) {
 					r = nfsvno_getfh(nvp, &nfh, p);
 					if (!r)
 					    r = nfsvno_getattr(nvp, nvap,
@@ -2169,17 +2181,25 @@ again:
 					    if (new_mp == mp)
 						new_mp = nvp->v_mount;
 					}
-				    }
-				} else {
-				    nvp = NULL;
 				}
-				if (r) {
+
+				/*
+				 * If we failed to get attributes of the entry,
+				 * then just skip it for NFSv3 (the traditional
+				 * behavior in the old NFS server).
+				 * For NFSv4 the behavior is controlled by
+				 * RDATTRERROR: we either ignore the error or
+				 * fail the request.
+				 * Note that RDATTRERROR is never set for NFSv3.
+				 */
+				if (r != 0) {
 					if (!NFSISSET_ATTRBIT(&attrbits,
 					    NFSATTRBIT_RDATTRERROR)) {
-						if (nvp != NULL)
-							vput(nvp);
+						vput(nvp);
 						if (needs_unbusy != 0)
 							vfs_unbusy(new_mp);
+						if ((nd->nd_flag & ND_NFSV3))
+							goto invalid;
 						nd->nd_repstat = r;
 						break;
 					}
@@ -2248,6 +2268,7 @@ again:
 			if (dirlen <= cnt)
 				entrycnt++;
 		}
+invalid:
 		cpos += dp->d_reclen;
 		dp = (struct dirent *)cpos;
 		cookiep++;