Hi Curt,
In journal mode, IMHO the case you described also happens. Could you
shed light on journal mode case?
Thanks,
Yongqiang.
On Tue, Jun 1, 2010 at 8:03 PM, Theodore Ts'o <tytso@xxxxxxx> wrote:
> From: Curt Wohlgemuth <curtw@xxxxxxxxxx>
>
> commit 8b472d739b2ddd8ab7fb278874f696cd95b25a5e upstream (as of v2.6.34-rc6)
>
> In the no-journal case, ext4_write_inode() will fetch the bh and call
> sync_dirty_buffer() on it. However, if the bh has already been
> written and the bh reclaimed for some other purpose, AND if the inode
> is the only one in the inode table block in use, then
> ext4_get_inode_loc() will not read the inode table block from disk,
> but as an optimization, fill the block with zero's assuming that its
> caller will copy in the on-disk version of the inode. This is not
> done by ext4_write_inode(), so the contents of the inode can simply
> get lost. The fix is to use __ext4_get_inode_loc() with in_mem set to
> 0, instead of ext4_get_inode_loc(). Long term the API needs to be
> fixed so it's obvious why latter is not safe.
>
> Addresses-Google-Bug: #2526446
>
> Signed-off-by: Curt Wohlgemuth <curtw@xxxxxxxxxx>
> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
> ---
> fs/ext4/inode.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index ff04c74..28152f8 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -5204,7 +5204,7 @@ int ext4_write_inode(struct inode *inode, int wait)
> } else {
> struct ext4_iloc iloc;
>
> - err = ext4_get_inode_loc(inode, &iloc);
> + err = __ext4_get_inode_loc(inode, &iloc, 0);
> if (err)
> return err;
> if (wait)
> --
> 1.6.6.1.1.g974db.dirty
>
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--
Best Wishes
Yongqiang Yang
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