Re: [GIT PULL] Squashfs fixes for 2.6.29?

From: Woody Suwalski
Date: Tue Mar 10 2009 - 09:30:54 EST


Geert Uytterhoeven wrote:
On Tue, 10 Mar 2009, Phillip Lougher wrote:
Stefan Lippers-Hollmann wrote:
This patch seems to break squashfs for me on i386 and amd64. Test environment is a squashed filesystem image (live CD image, but also
tested manually with a loop mounted iso9660 and loop mounted squashfs;
kernel 2.6.29-rc7-git2). The squashfs image has been created with
squashfs-tools CVS[1] as of today (latest commit 2009-03-03).

Can you send me a filesystem (or link to one) which exhibits this? Zlib is
obviously showing unexpected behaviour...

I see the same thing here. I'll send you a test file system by private email.

The patch below fixes it. It seems zlib sometimes does need an additional
loop ;-)

Note that I expect it may now loop forever in case of file system corruption.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx>

diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 321728f..46358dd 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -184,15 +184,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
offset = 0;
}
- if (msblk->stream.avail_out == 0) {
- if (page == pages) {
- ERROR("zlib_inflate tried to "
- "decompress too much data, "
- "expected %d bytes. Zlib "
- "data probably corrupt\n",
- srclength);
- goto release_mutex;
- }
+ if (msblk->stream.avail_out == 0 && page < pages) {
msblk->stream.next_out = buffer[page++];
msblk->stream.avail_out = PAGE_CACHE_SIZE;
}

With kind regards,

Geert Uytterhoeven
Software Architect

Same here. I have experimentally commented out the "goto release_mutex" and I see that the error message is printed once or twice during boot.
(and we are banging on it heavily - no real file system problems seen).
In my case squash4 is a 600M+ all the system partition to be aufs'd with a read-write portion.
Leaving the patch as it is renders the system unbootable - weird errors resulting from aborted reads....

Woody

--
Woody Suwalski, Xandros, Ottawa, Canada, 1-613-842-3498 x414

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