From: Michael Vrable <mvrable@cs.ucsd.edu>
Date: Thu, 7 Jan 2010 00:05:25 +0000 (-0800)
Subject: Improve NFS readdirplus to estimate response sizes.
X-Git-Url: https://git.vrable.net/?a=commitdiff_plain;h=53162a864578bcfbc2c35cbc59b9395d7108a2fe;p=bluesky.git

Improve NFS readdirplus to estimate response sizes.

It should now give a response closer to, but not larger than, the requested
size.
---

diff --git a/nfs3/nfs3.c b/nfs3/nfs3.c
index 4b1b8c5..70273ff 100644
--- a/nfs3/nfs3.c
+++ b/nfs3/nfs3.c
@@ -747,7 +747,7 @@ nfsproc3_link_3_svc(link3args *argp, struct svc_req *rqstp)
 gint bluesky_dirent_compare(gconstpointer a, gconstpointer b,
                             gpointer unused);
 
-#define MAX_READDIR_DIRENTS 4
+#define MAX_READDIR_DIRENTS 64
 readdir3res *
 nfsproc3_readdir_3_svc(readdir3args *argp, struct svc_req *rqstp)
 {
@@ -797,6 +797,13 @@ nfsproc3_readdir_3_svc(readdir3args *argp, struct svc_req *rqstp)
 readdirplus3res *
 nfsproc3_readdirplus_3_svc(readdirplus3args *argp, struct svc_req *rqstp)
 {
+    /* XDR-encoded sizes:
+     *   post_op_attr: 88 bytes
+     *   base readdirplus3resok: 88 + 16 bytes
+     *   base directory entry: 24 bytes + filename
+     *   attributes/fh3: 88 + 8 + filehandle size
+     */
+    size_t dircount = 88 + 16, attrcount = 0;
     static readdirplus3res result;
 
     BlueSkyInode *dir = lookup_fh(&argp->dir);
@@ -826,6 +833,11 @@ nfsproc3_readdirplus_3_svc(readdirplus3args *argp, struct svc_req *rqstp)
         BlueSkyDirent *d = g_sequence_get(i);
         BlueSkyInode *inode = bluesky_get_inode(fs, d->inum);
         if (inode != NULL) {
+            dircount += 24 + ((strlen(d->name) + 3) & ~3);
+            attrcount += 88 + 8 + 8;
+            if (dircount > argp->dircount
+                || dircount + attrcount > argp->maxcount)
+                break;
             dirents[count].fileid = d->inum;
             dirents[count].name = d->name;
             dirents[count].cookie = d->cookie;