Re: [PATCH] direct IO breaks root filesystem

GOTO Masanori (gotom@debian.org)
Tue, 11 Dec 2001 20:30:40 +0900


At Tue, 11 Dec 2001 04:13:06 -0500 (EST),
Alexander Viro <viro@math.psu.edu> wrote:
> > + /*
> > + * If inode is BLK and it is not already mounted,
> > + * blocksize change hardsect_size.
> > + */
> > + if (S_ISBLK(inode->i_mode) && !is_mounted(inode->i_rdev)) {
>
> That's obviously wrong. What's to stop it from getting mounted
> right after that check?

Ah! You're right. I was confused, I'm sorry.
New patch is here (and works well)... Ugh.

--- linux-2.4.17-pre8.vanilla/mm/filemap.c Tue Dec 11 15:54:57 2001
+++ linux-2.4.17-pre8/mm/filemap.c Tue Dec 11 19:36:09 2001
@@ -1508,8 +1508,21 @@
new_iobuf = 1;
}

- blocksize = 1 << inode->i_blkbits;
- blocksize_bits = inode->i_blkbits;
+ /*
+ * If inode is block device, blocksize is set as hardsect_size.
+ */
+ if (S_ISBLK(inode->i_mode)) {
+ int size;
+
+ size = get_hardsect_size(inode->i_rdev);
+ blocksize = size;
+ for (blocksize_bits = 0; !(size & 1); )
+ size >>= 1, blocksize_bits++;
+ } else {
+ blocksize = 1 << inode->i_blkbits;
+ blocksize_bits = inode->i_blkbits;
+ }
+
blocksize_mask = blocksize - 1;
chunk_size = KIO_MAX_ATOMIC_IO << 10;

-- gotom
-
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