From: Andrea Arcangeli <andrea@suse.de>
To: Alexander Viro <viro@math.psu.edu>
Cc: Linus Torvalds <torvalds@transmeta.com>,
Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 2.4.10-pre11
Date: Fri, 21 Sep 2001 06:46:21 +0200 [thread overview]
Message-ID: <20010921064621.C729@athlon.random> (raw)
In-Reply-To: <20010921003136.H729@athlon.random> <Pine.GSO.4.21.0109201835320.5631-100000@weyl.math.psu.edu> <20010921010340.L729@athlon.random> <20010921054749.Z729@athlon.random> <20010921060625.A729@athlon.random>
In-Reply-To: <20010921060625.A729@athlon.random>; from andrea@suse.de on Fri, Sep 21, 2001 at 06:06:25AM +0200
On Fri, Sep 21, 2001 at 06:06:25AM +0200, Andrea Arcangeli wrote:
> On Fri, Sep 21, 2001 at 05:47:49AM +0200, Andrea Arcangeli wrote:
> > write and I cannot zero it out. It is getting harder to fix this one
> > just inside the ->make_request callback... Hints?
>
> I think the best fix is to have the ramdisk using the same aops of ramfs
> and replace "Secure" with "Uptodate". We need to trap the security issue
> at the higher layer and also this will avoid us having to map useless
> bh, so it should be an improvement, only the filesystem will end
> triggering the ->make_request callback of the ramdisk. Then if the fs
> does I/O on stuff out of the physical address space we'll just clear it
> out.
ok, here it is, this obsoletes the previous patch (so again against
2.4.10pre12), initrd works again.
Al, feel free to expand over rd.c now.
diff -urN ramdisk-ref/drivers/block/rd.c ramdisk/drivers/block/rd.c
--- ramdisk-ref/drivers/block/rd.c Fri Sep 21 06:39:28 2001
+++ ramdisk/drivers/block/rd.c Fri Sep 21 06:26:37 2001
@@ -186,17 +186,77 @@
#endif
+/*
+ * Copyright (C) 2000 Linus Torvalds.
+ * 2000 Transmeta Corp.
+ * aops copied from ramfs.
+ */
+static int ramdisk_readpage(struct file *file, struct page * page)
+{
+ if (!Page_Uptodate(page)) {
+ memset(kmap(page), 0, PAGE_CACHE_SIZE);
+ kunmap(page);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+ UnlockPage(page);
+ return 0;
+}
+
+/*
+ * Writing: just make sure the page gets marked dirty, so that
+ * the page stealer won't grab it.
+ */
+static int ramdisk_writepage(struct page *page)
+{
+ SetPageDirty(page);
+ UnlockPage(page);
+ return 0;
+}
+
+static int ramdisk_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+ void *addr = kmap(page);
+ if (!Page_Uptodate(page)) {
+ memset(addr, 0, PAGE_CACHE_SIZE);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+ SetPageDirty(page);
+ return 0;
+}
+
+static int ramdisk_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+ kunmap(page);
+ return 0;
+}
+
+struct address_space_operations ramdisk_aops = {
+ readpage: ramdisk_readpage,
+ writepage: ramdisk_writepage,
+ prepare_write: ramdisk_prepare_write,
+ commit_write: ramdisk_commit_write,
+};
+
static int rd_blkdev_pagecache_IO(int rw, struct buffer_head * sbh, int minor)
{
- struct address_space * mapping = rd_inode[minor]->i_mapping;
+ struct address_space * mapping;
unsigned long index;
- int offset, size, err = 0;
+ int offset, size, err;
- if (sbh->b_page->mapping == mapping) {
- if (rw != READ)
- SetPageDirty(sbh->b_page);
+ err = -EIO;
+ /*
+ * If we did BLKFLSBUF just before doing read/write,
+ * we could see a rd_inode before the opener had a chance
+ * to return from rd_open(), that's ok, as soon as we
+ * see the inode we can use its i_mapping, and the inode
+ * cannot go away from under us.
+ */
+ if (!rd_inode[minor])
goto out;
- }
+ err = 0;
+ mapping = rd_inode[minor]->i_mapping;
index = sbh->b_rsector >> (PAGE_CACHE_SHIFT - 9);
offset = (sbh->b_rsector << 9) & ~PAGE_CACHE_MASK;
@@ -206,8 +266,7 @@
int count;
struct page ** hash;
struct page * page;
- const char * src;
- char * dst;
+ char * src, * dst;
int unlock = 0;
count = PAGE_CACHE_SIZE - offset;
@@ -217,20 +276,24 @@
hash = page_hash(mapping, index);
page = __find_get_page(mapping, index, hash);
- if (!page && rw != READ) {
+ if (!page) {
page = grab_cache_page(mapping, index);
err = -ENOMEM;
if (!page)
goto out;
err = 0;
+
+ if (!Page_Uptodate(page)) {
+ memset(kmap(page), 0, PAGE_CACHE_SIZE);
+ kunmap(page);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+
unlock = 1;
}
index++;
- if (!page) {
- offset = 0;
- continue;
- }
if (rw == READ) {
src = kmap(page);
@@ -321,6 +384,13 @@
struct block_device * bdev = inode->i_bdev;
down(&bdev->bd_sem);
+ /*
+ * We're the only users here, protected by the
+ * bd_sem, but first check if we didn't just
+ * flushed the ramdisk.
+ */
+ if (!rd_inode[minor])
+ goto unlock;
if (bdev->bd_openers > 2) {
up(&bdev->bd_sem);
return -EBUSY;
@@ -328,8 +398,16 @@
bdev->bd_openers--;
bdev->bd_cache_openers--;
iput(rd_inode[minor]);
+ /*
+ * Make sure the cache is flushed from here
+ * and not from close(2), somebody
+ * could reopen the device before we have a
+ * chance to close it ourself.
+ */
+ truncate_inode_pages(rd_inode[minor]->i_mapping, 0);
rd_inode[minor] = NULL;
rd_blocksizes[minor] = rd_blocksize;
+ unlock:
up(&bdev->bd_sem);
}
break;
@@ -421,6 +499,8 @@
bdev->bd_openers++;
bdev->bd_cache_openers++;
bdev->bd_inode = inode;
+
+ inode->i_mapping->a_ops = &ramdisk_aops;
}
}
Andrea
next prev parent reply other threads:[~2001-09-21 4:46 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-18 0:08 Linux 2.4.10-pre11 Linus Torvalds
2001-09-17 23:17 ` Marcelo Tosatti
2001-09-18 1:08 ` Marcelo Tosatti
2001-09-18 3:37 ` Andrea Arcangeli
2001-09-18 2:25 ` Marcelo Tosatti
2001-09-18 3:58 ` Andrea Arcangeli
2001-09-18 2:53 ` Marcelo Tosatti
2001-09-18 4:54 ` Andrea Arcangeli
2001-09-18 3:33 ` Marcelo Tosatti
2001-09-18 5:06 ` Andrea Arcangeli
2001-09-18 3:55 ` Marcelo Tosatti
2001-09-18 5:32 ` Andrea Arcangeli
2001-09-18 4:14 ` Marcelo Tosatti
2001-09-18 5:59 ` Andrea Arcangeli
2001-09-18 5:00 ` Marcelo Tosatti
[not found] ` <20010917211834.A31693@redhat.com>
[not found] ` <20010918035055.J698@athlon.random>
2001-09-18 2:02 ` Andrea Arcangeli
[not found] ` <20010917221653.B31693@redhat.com>
2001-09-18 2:27 ` Linus Torvalds
2001-09-18 3:14 ` Alan Cox
2001-09-18 3:26 ` Andrea Arcangeli
[not found] ` <20010918052201.N698@athlon.random>
2001-09-18 4:01 ` Benjamin LaHaise
2001-09-18 4:39 ` Andrea Arcangeli
2001-09-18 5:04 ` Alan Cox
2001-09-18 5:09 ` Andrea Arcangeli
2001-09-18 5:22 ` Benjamin LaHaise
2001-09-18 5:48 ` Andrea Arcangeli
2001-09-18 5:48 ` Andrew Morton
2001-09-18 6:11 ` Andrea Arcangeli
2001-09-18 5:02 ` Marcelo Tosatti
2001-09-18 6:40 ` Andrea Arcangeli
2001-09-18 16:06 ` Marcelo Tosatti
2001-09-18 19:18 ` Marcelo Tosatti
2001-09-18 21:05 ` Andrea Arcangeli
2001-09-19 13:57 ` Rik van Riel
2001-09-18 10:58 ` Martin Dalecki
2001-09-18 9:31 ` Alexander Viro
2001-09-18 9:39 ` Andrea Arcangeli
2001-09-18 9:44 ` Alexander Viro
2001-09-18 9:57 ` Andrea Arcangeli
2001-09-18 10:02 ` Alexander Viro
2001-09-18 10:17 ` Andrea Arcangeli
2001-09-18 10:28 ` Alexander Viro
2001-09-18 10:35 ` Andrea Arcangeli
2001-09-18 10:52 ` Alexander Viro
2001-09-18 11:05 ` Helge Hafting
2001-09-18 12:40 ` Andrea Arcangeli
2001-09-18 17:02 ` Linus Torvalds
2001-09-18 16:45 ` Linus Torvalds
2001-09-18 18:19 ` Alexander Viro
2001-09-18 18:27 ` Linus Torvalds
2001-09-18 19:14 ` Andreas Dilger
2001-09-18 19:41 ` Alexander Viro
2001-09-18 20:33 ` Richard Gooch
2001-09-18 20:53 ` Alexander Viro
2001-09-18 21:06 ` Richard Gooch
2001-09-18 21:27 ` Alexander Viro
2001-09-18 19:29 ` Benjamin LaHaise
2001-09-18 20:17 ` Stephan von Krawczynski
2001-09-18 20:33 ` Alan Cox
2001-09-19 13:42 ` Rik van Riel
2001-09-19 14:27 ` Alexander Viro
2001-09-19 2:59 ` Michael Peddemors
2001-09-19 16:11 ` Alexander Viro
2001-09-19 18:25 ` Andrea Arcangeli
2001-09-19 19:21 ` Alexander Viro
2001-09-19 20:55 ` Andrea Arcangeli
2001-09-19 21:17 ` Alexander Viro
2001-09-19 23:01 ` Andrea Arcangeli
2001-09-19 23:03 ` Andrea Arcangeli
2001-09-19 23:30 ` Alexander Viro
2001-09-19 23:40 ` Andrea Arcangeli
2001-09-20 13:56 ` Alexander Viro
2001-09-20 14:38 ` Chris Mason
2001-09-20 14:50 ` Alexander Viro
2001-09-20 15:44 ` Chris Mason
2001-09-20 16:43 ` Alexander Viro
2001-09-20 20:54 ` [PATCH] fs/block_dev.c cleanup Alexander Viro
2001-09-19 22:15 ` Linux 2.4.10-pre11 Richard Gooch
2001-09-20 2:34 ` Andrea Arcangeli
2001-09-20 10:52 ` Alexander Viro
2001-09-20 18:18 ` Andrea Arcangeli
2001-09-20 18:33 ` Alexander Viro
2001-09-20 18:59 ` Andrea Arcangeli
2001-09-20 20:41 ` Alexander Viro
2001-09-20 21:18 ` Andrea Arcangeli
2001-09-20 21:40 ` Alexander Viro
2001-09-20 22:13 ` Andrea Arcangeli
2001-09-20 22:20 ` Alexander Viro
2001-09-20 22:31 ` Andrea Arcangeli
2001-09-20 22:44 ` Alexander Viro
2001-09-20 23:03 ` Andrea Arcangeli
2001-09-20 23:11 ` Alexander Viro
2001-09-21 1:50 ` Alexander Viro
2001-09-21 2:42 ` Andrea Arcangeli
2001-09-21 3:47 ` Andrea Arcangeli
2001-09-21 4:00 ` Alexander Viro
2001-09-21 4:06 ` Andrea Arcangeli
2001-09-21 4:06 ` Andrea Arcangeli
2001-09-21 4:46 ` Andrea Arcangeli [this message]
2001-09-21 7:09 ` Andrea Arcangeli
2001-09-19 20:41 ` Richard Gooch
2001-09-19 13:38 ` Rik van Riel
2001-09-19 16:35 ` Andrea Arcangeli
2001-09-18 3:18 Ed Tomlinson
2001-09-18 2:31 ` Magnus Naeslund(f)
2001-09-18 2:49 ` David B. Stevens
2001-09-18 3:38 ` Ed Tomlinson
2001-09-18 3:15 ` Alan Cox
2001-09-18 4:41 ` H. Peter Anvin
2001-09-18 6:14 Alexei Podtelezhnikov
2001-09-18 13:51 ` Rik van Riel
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