Module Name: src
Committed By: manu
Date: Tue Jan 13 16:39:51 UTC 2015
Modified Files:
src/sys/fs/puffs: puffs_vnops.c
Log Message:
Make sure reads on empty files reach PUFFS filesystems
Sending a read through the page cache will get the operation
short-circuited. This is a problem with some filesystems that
expect to receive the read operation in order to update atime.
We fix that by bypassing the page cache when reading a file
wich a size known to be zero.
To generate a diff of this commit:
cvs rdiff -u -r1.198 -r1.199 src/sys/fs/puffs/puffs_vnops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/fs/puffs/puffs_vnops.c
diff -u src/sys/fs/puffs/puffs_vnops.c:1.198 src/sys/fs/puffs/puffs_vnops.c:1.199
--- src/sys/fs/puffs/puffs_vnops.c:1.198 Tue Nov 4 09:14:42 2014
+++ src/sys/fs/puffs/puffs_vnops.c Tue Jan 13 16:39:51 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: puffs_vnops.c,v 1.198 2014/11/04 09:14:42 manu Exp $ */
+/* $NetBSD: puffs_vnops.c,v 1.199 2015/01/13 16:39:51 manu Exp $ */
/*
* Copyright (c) 2005, 2006, 2007 Antti Kantee. All Rights Reserved.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.198 2014/11/04 09:14:42 manu Exp $");
+__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.199 2015/01/13 16:39:51 manu Exp $");
#include <sys/param.h>
#include <sys/buf.h>
@@ -2279,9 +2279,17 @@ puffs_vnop_read(void *v)
if (uio->uio_offset < 0)
return EFBIG;
+ /*
+ * On the case of reading empty files and (vp->v_size != 0) below:
+ * some filesystems (hint: FUSE and distributed filesystems) still
+ * expect to get the READ in order to update atime. Reading through
+ * the case filters empty files, therefore we prefer to bypass the
+ * cache here.
+ */
if (vp->v_type == VREG &&
PUFFS_USE_PAGECACHE(pmp) &&
- !(pn->pn_stat & PNODE_RDIRECT)) {
+ !(pn->pn_stat & PNODE_RDIRECT) &&
+ (vp->v_size != 0)) {
const int advice = IO_ADV_DECODE(ap->a_ioflag);
while (uio->uio_resid > 0) {
