Hi,
Don't worry about the wrong list, I did spot the patch anyway. I agree
with the principle of what you are trying to do, but something isn't
quite right. When I tried this on Friday I got a NULL pointer deref the
first time I tried to touch a file on the fs.
I think it needs a bit more work, but its certainly going in the right
direction,
Steve.
On Fri, 2009-08-14 at 23:05 +0800, Wengang Wang wrote:
> this patch is for the same problem that Benjamin Marzinski fixes at commit
> b94a170e96dc416828af9d350ae2e34b70ae7347
>
> quotation of the original problem:
>
> ---cut here---
> When a file is deleted from a gfs2 filesystem on one node, a dcache
> entry for it may still exist on other nodes in the cluster. If this
> happens, gfs2 will be unable to free this file on disk. Because of this,
> it's possible to have a gfs2 filesystem with no files on it and no free
> space. With this patch, when a node receives a callback notifying it
> that the file is being deleted on another node, it schedules a new
> workqueue thread to remove the file's dcache entry.
> ---end cut---
>
> after applying Benjamin's patch, I think there is still a case in which the
> disk
> inode remains even when "no space" is hit. the case is that when running
> d_prune_aliases() against the inode, there are one or more dentries(aliases)
> which have reference count number > 0. in this case the dentries won't be
> pruned.
> and even later, the reference cound becomes to 0, the dentries can still be
> cached in memory. unfortunately, no callback come again, things come back to
> the state before the callback runs. thus the on disk inode remains there until
> in memory inode is removed for some other reason(shrinking inode cache or
> unmount
> the gfs2 volume..).
>
> this patch is to remove those dentries when their reference count becomes to
> 0 and
> the inode is deleted by remote node. for implementation, gfs2_dentry_delete()
> is
> added as dentry_operations.d_delete. the function returns true when the inode
> is
> deleted by remote node. in dput(), gfs2_dentry_delete() is called and since it
> returns true, the dentry is unhashed from dcache and then removed. when all
> dentries
> are removed, the in memory inode get removed so that the on disk inode can be
> freed.
>
> Signed-off-by: Wengang Wang <wen.gang.w...@oracle.com>
> ---
> fs/gfs2/dentry.c | 11 +++++++++++
> 1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/fs/gfs2/dentry.c b/fs/gfs2/dentry.c
> index 022c66c..434f204 100644
> --- a/fs/gfs2/dentry.c
> +++ b/fs/gfs2/dentry.c
> @@ -107,8 +107,19 @@ static int gfs2_dhash(struct dentry *dentry, struct qstr
> *str)
> return 0;
> }
>
> +static int gfs2_dentry_delete(struct dentry *dentry)
> +{
> + struct gfs2_inode *ginode = GFS2_I(dentry->d_inode);
> +
> + if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
> + return 1;
> +
> + return 0;
> +}
> +
> const struct dentry_operations gfs2_dops = {
> .d_revalidate = gfs2_drevalidate,
> .d_hash = gfs2_dhash,
> + .d_delete = gfs2_dentry_delete,
> };
>
