From: Christoph Hellwig <hch@infradead.org>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: Christoph Hellwig <hch@infradead.org>,
Josef 'Jeff' Sipek <jeffpc@josefsipek.net>,
xfs@oss.sgi.com
Subject: Re: [PATCH 12/13] xfs: add version 3 inode format with CRCs
Date: Thu, 12 Feb 2009 13:51:54 -0500 [thread overview]
Message-ID: <20090212185154.GA18280@infradead.org> (raw)
In-Reply-To: <49946D7A.6070806@sandeen.net>
On Thu, Feb 12, 2009 at 12:42:02PM -0600, Eric Sandeen wrote:
> Josef 'Jeff' Sipek wrote:
> > On Tue, Feb 10, 2009 at 03:22:53PM -0500, Christoph Hellwig wrote:
> > ...
> >> Index: xfs/fs/xfs/xfs_dinode.h
> >> ===================================================================
> >> --- xfs.orig/fs/xfs/xfs_dinode.h 2009-02-10 19:45:51.939069576 +0100
> >> +++ xfs/fs/xfs/xfs_dinode.h 2009-02-10 19:45:59.195068745 +0100
> >> @@ -69,11 +69,32 @@ typedef struct xfs_dinode {
> >>
> >> /* di_next_unlinked is the only non-core field in the old dinode */
> >> __be32 di_next_unlinked;/* agi unlinked list ptr */
> >> -} __attribute__((packed)) xfs_dinode_t;
> >> +
> >> + /* start of the extended dinode, writable fields */
> >> + __be32 di_crc; /* CRC of the inode */
> >> + __be64 di_changecount; /* number of attribute changes */
> >> + __u8 di_pad2[16]; /* more padding for future expansion */
> >> +
> >> + /* fields only written to during inode creation */
> >> + xfs_timestamp_t di_crtime; /* time created */
> >> + __be64 di_ino; /* inode number */
> >> + uuid_t di_uuid; /* UUID of the filesystem */
> >> +} xfs_dinode_t;
> >
> > Hrm...removing the packed attribute... Eric, do you remember the ARM ABI
> > alignment rules? Regardless of ARM, are those fields aligned nicely? (From a
> > quick glance at the code looks ok.)
>
> I'll just have to just test it again I suppose. Removing packed is
> good, as long as the padding makes it all come out right.
The reason why the current dinode needs the packed attribute is that
it's end on an un-even 32bit word, and thus the last field might be
wrongly aligned on 64-bit big-endian platforms (same issue as the
bad features2 one). With the CRC patchset we now have a dinode
that's properly aligned on a even 32bit word.
>
> -=Eric
---end quoted text---
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next prev parent reply other threads:[~2009-02-12 18:52 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-10 20:22 [PATCH 00/13] Updated CRC patches Christoph Hellwig
2009-02-10 20:22 ` [PATCH 01/13] xfs: cleanup xlog_bread Christoph Hellwig
2009-02-10 20:22 ` [PATCH 02/13] xfs: remove m_litino Christoph Hellwig
2009-02-10 20:22 ` [PATCH 03/13] xfs: remove m_attroffset Christoph Hellwig
2009-02-10 20:22 ` [PATCH 04/13] xfs: take inode version into account in XFS_LITINO Christoph Hellwig
2009-02-10 20:22 ` [PATCH 05/13] xfs: add CRC infrastructure Christoph Hellwig
2009-02-12 6:10 ` Josef 'Jeff' Sipek
2009-02-10 20:22 ` [PATCH 06/13] xfs: add support for large btree blocks Christoph Hellwig
2009-02-10 20:22 ` [PATCH 07/13] xfs: add CRC checks to the superblock Christoph Hellwig
2009-02-10 20:22 ` [PATCH 08/13] xfs: add CRC checks to the AGF Christoph Hellwig
2009-02-10 20:22 ` [PATCH 09/13] xfs: add CRC checks to the AGI Christoph Hellwig
2009-02-10 20:22 ` [PATCH 10/13] xfs: add CRC checks to the AGFL Christoph Hellwig
2009-02-11 7:54 ` Dave Chinner
2009-02-15 18:23 ` Christoph Hellwig
2009-02-10 20:22 ` [PATCH 11/13] xfs: add CRC checks to the log Christoph Hellwig
2009-02-10 20:22 ` [PATCH 12/13] xfs: add version 3 inode format with CRCs Christoph Hellwig
2009-02-12 6:38 ` Josef 'Jeff' Sipek
2009-02-12 18:42 ` Eric Sandeen
2009-02-12 18:51 ` Christoph Hellwig [this message]
2009-02-10 20:22 ` [PATCH 13/13] xfs: add CRC checks for quota blocks Christoph Hellwig
2009-02-12 6:41 ` Josef 'Jeff' Sipek
2009-02-13 20:10 ` Christoph Hellwig
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