Module Name: src
Committed By: uebayasi
Date: Sat Jan 30 12:06:20 UTC 2010
Modified Files:
src/sys/miscfs/genfs: genfs_io.c
Log Message:
Reduce the diff between genfs_getpages() and genfs_do_io(). These should be
merged eventually.
To generate a diff of this commit:
cvs rdiff -u -r1.35 -r1.36 src/sys/miscfs/genfs/genfs_io.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/miscfs/genfs/genfs_io.c
diff -u src/sys/miscfs/genfs/genfs_io.c:1.35 src/sys/miscfs/genfs/genfs_io.c:1.36
--- src/sys/miscfs/genfs/genfs_io.c:1.35 Sat Jan 30 05:19:20 2010
+++ src/sys/miscfs/genfs/genfs_io.c Sat Jan 30 12:06:20 2010
@@ -1,4 +1,4 @@
-/* $NetBSD: genfs_io.c,v 1.35 2010/01/30 05:19:20 uebayasi Exp $ */
+/* $NetBSD: genfs_io.c,v 1.36 2010/01/30 12:06:20 uebayasi Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1993
@@ -31,7 +31,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.35 2010/01/30 05:19:20 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.36 2010/01/30 12:06:20 uebayasi Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -490,8 +490,9 @@
error = VOP_BMAP(vp, lbn, &devvp, &blkno, &run);
if (error) {
UVMHIST_LOG(ubchist, "VOP_BMAP lbn 0x%x -> %d\n",
- lbn, error,0,0);
+ lbn,error,0,0);
skipbytes += bytes;
+ bytes = 0;
goto loopdone;
}
@@ -521,7 +522,7 @@
* mark the pages we zeroed PG_RDONLY.
*/
- if (blkno < 0) {
+ if (blkno == (daddr_t)-1) {
int holepages = (round_page(offset + iobytes) -
trunc_page(offset)) >> PAGE_SHIFT;
UVMHIST_LOG(ubchist, "lbn 0x%x -> HOLE", lbn,0,0,0);
@@ -551,6 +552,8 @@
if (offset == startoffset && iobytes == bytes) {
bp = mbp;
} else {
+ UVMHIST_LOG(ubchist, "vp %p bp %p num now %d",
+ vp, bp, vp->v_numoutput, 0);
bp = getiobuf(vp, true);
nestiobuf_setup(mbp, bp, offset - startoffset, iobytes);
}
@@ -562,7 +565,7 @@
UVMHIST_LOG(ubchist,
"bp %p offset 0x%x bcount 0x%x blkno 0x%x",
- bp, offset, iobytes, bp->b_blkno);
+ bp, offset, bp->b_bcount, bp->b_blkno);
VOP_STRATEGY(devvp, bp);
}
@@ -1283,13 +1286,11 @@
genfs_do_io(struct vnode *vp, off_t off, vaddr_t kva, size_t len, int flags,
enum uio_rw rw, void (*iodone)(struct buf *))
{
- int s, error, run;
+ int s, error;
int fs_bshift, dev_bshift;
off_t eof, offset, startoffset;
size_t bytes, iobytes, skipbytes;
- daddr_t lbn, blkno;
struct buf *mbp, *bp;
- struct vnode *devvp;
const bool async = (flags & PGO_SYNCIO) == 0;
const bool iowrite = rw == UIO_WRITE;
const int brw = iowrite ? B_WRITE : B_READ;
@@ -1343,27 +1344,56 @@
for (offset = startoffset;
bytes > 0;
offset += iobytes, bytes -= iobytes) {
+ int run;
+ daddr_t lbn, blkno;
+ struct vnode *devvp;
+
+ /*
+ * bmap the file to find out the blkno to read from and
+ * how much we can read in one i/o. if bmap returns an error,
+ * skip the rest of the top-level i/o.
+ */
+
lbn = offset >> fs_bshift;
error = VOP_BMAP(vp, lbn, &devvp, &blkno, &run);
if (error) {
- UVMHIST_LOG(ubchist, "VOP_BMAP() -> %d", error,0,0,0);
+ UVMHIST_LOG(ubchist, "VOP_BMAP lbn 0x%x -> %d\n",
+ lbn,error,0,0);
skipbytes += bytes;
bytes = 0;
- break;
+ goto loopdone;
}
+ /*
+ * see how many pages can be read with this i/o.
+ * reduce the i/o size if necessary to avoid
+ * overwriting pages with valid data.
+ */
+
iobytes = MIN((((off_t)lbn + 1 + run) << fs_bshift) - offset,
bytes);
+
+ /*
+ * if this block isn't allocated, zero it instead of
+ * reading it. unless we are going to allocate blocks,
+ * mark the pages we zeroed PG_RDONLY.
+ */
+
if (blkno == (daddr_t)-1) {
if (!iowrite) {
memset((char *)kva + (offset - startoffset), 0,
- iobytes);
+ iobytes);
}
skipbytes += iobytes;
continue;
}
- /* if it's really one i/o, don't make a second buf */
+ /*
+ * allocate a sub-buf for this piece of the i/o
+ * (or just use mbp if there's only 1 piece),
+ * and start it going.
+ */
+
if (offset == startoffset && iobytes == bytes) {
bp = mbp;
} else {
@@ -1377,12 +1407,15 @@
/* adjust physical blkno for partial blocks */
bp->b_blkno = blkno + ((offset - ((off_t)lbn << fs_bshift)) >>
dev_bshift);
+
UVMHIST_LOG(ubchist,
- "vp %p offset 0x%x bcount 0x%x blkno 0x%x",
- vp, offset, bp->b_bcount, bp->b_blkno);
+ "bp %p offset 0x%x bcount 0x%x blkno 0x%x",
+ bp, offset, bp->b_bcount, bp->b_blkno);
VOP_STRATEGY(devvp, bp);
}
+
+loopdone:
if (skipbytes) {
UVMHIST_LOG(ubchist, "skipbytes %d", skipbytes, 0,0,0);
}
