hgfs: make data files with meta headers having the right size after open

to get the right data size of a file, the revlog needs to have been
opened and the metaheader parsed. as an optimization, we used to
open revlog only on the first read resulting revlogs with metaheaders
having the wrong size returned by fstat() until the first read().

tar relies on fstat() giving the correct file size, so just open
the revlog on open. reading directories can still yield the wrong
size but it is not that critical.

1 files changed, 15 insertions, 14 deletions

diff --git a/sys/src/cmd/hgfs/fs.c b/sys/src/cmd/hgfs/fs.c
index ab820f656..09644b8a5 100644
--- a/sys/src/cmd/hgfs/fs.c
+++ b/sys/src/cmd/hgfs/fs.c
@@ -606,6 +606,19 @@ fsopen(Req *r)
 		if(rf->node == nil || rf->node->mode != 'x')
 			break;
 	case OREAD:
+		if(rf->level == Qlog){
+			if((rf->fd = revlogopentemp(&changelog, hashrev(&changelog, rf->info->chash))) < 0){
+				responderror(r);
+				return;
+			}
+			rf->doff = rf->info->logoff;
+		} else if(rf->level == Qtree && rf->node->down == nil){
+			if((rf->fd = revlogopentemp(rf->rlog, hashrev(rf->rlog, rf->node->hash))) < 0){
+				responderror(r);
+				return;
+			}
+			rf->doff = fmetaheader(rf->fd);
+		}
 		respond(r, nil);
 		return;
 	}
@@ -697,13 +710,6 @@ fsread(Req *r)
 			len = 0;
 		else if((off + len) >= rf->info->loglen)
 			len = rf->info->loglen - off;
-		if(rf->fd >= 0)
-			goto Fdgen;
-		if((rf->fd = revlogopentemp(&changelog, hashrev(&changelog, rf->info->chash))) < 0){
-			responderror(r);
-			return;
-		}
-		rf->doff = rf->info->logoff;
 		goto Fdgen;
 	case Qwho:
 		s = rf->info->who;
@@ -724,14 +730,9 @@ fsread(Req *r)
 			respond(r, nil);
 			return;
 		}
-		if(rf->fd >= 0)
-			goto Fdgen;
-		if((rf->fd = revlogopentemp(rf->rlog, hashrev(rf->rlog, rf->node->hash))) < 0){
-			responderror(r);
-			return;
-		}
-		rf->doff = fmetaheader(rf->fd);
 	Fdgen:
+		if(rf->fd < 0)
+			break;
 		if((n = pread(rf->fd, r->ofcall.data, len, off + rf->doff)) < 0){
 			responderror(r);
 			return;