Re: [PATCH] dcache: fix d_splice_alias handling of aliases

From: Steven Whitehouse
Date: Fri Jan 17 2014 - 05:10:30 EST


Hi,

On Thu, 2014-01-16 at 13:51 -0500, J. Bruce Fields wrote:
> On Thu, Jan 16, 2014 at 11:54:07AM -0500, Bob Peterson wrote:
> > ----- Original Message -----
> > | Something like this?
> > (snip)
> > | @@ -779,6 +782,11 @@ static struct dentry *__gfs2_lookup(struct inode *dir,
> > | struct dentry *dentry,
> > | }
> > |
> > | d = d_splice_alias(inode, dentry);
> > | + if (IS_ERR(d)) {
> > | + iput(inode);
> > | + gfs2_glock_dq_uninit(&gh);
> > | + return ERR_PTR(error);
> >
> > ---------------------------------^
> > Shouldn't that be ERR_PTR(d)?
>
> Oops, yeah--well, actually just "d" I guess.
>
> This is what I've got for what it's worth.
>
> --b.
>

I think the patch looks ok to me. Did you give it a spin to test it? If
so then I will put it in the GFS2 -nmw tree,

Steve.

> commit 6fba5295019b52a03d76c9e9570952466051a7a6
> Author: J. Bruce Fields <bfields@xxxxxxxxxx>
> Date: Thu Jan 16 11:44:53 2014 -0500
>
> gfs2: revert "GFS2: d_splice_alias() can't return error"
>
> 0d0d110720d7960b77c03c9f2597faaff4b484ae asserts that "d_splice_alias()
> can't return error unless it was given an IS_ERR(inode)".
>
> That was true of the implementation of d_splice_alias, but this is
> really a problem with d_splice_alias: at a minimum it should be able to
> return -ELOOP in the case where inserting the given dentry would cause a
> directory loop.
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>
> diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
> index 7119504..3f44902 100644
> --- a/fs/gfs2/inode.c
> +++ b/fs/gfs2/inode.c
> @@ -585,6 +585,9 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
> error = PTR_ERR(inode);
> if (!IS_ERR(inode)) {
> d = d_splice_alias(inode, dentry);
> + error = PTR_ERR(d);
> + if (IS_ERR(d))
> + goto fail_gunlock;
> error = 0;
> if (file) {
> if (S_ISREG(inode->i_mode)) {
> @@ -779,6 +782,11 @@ static struct dentry *__gfs2_lookup(struct inode *dir, struct dentry *dentry,
> }
>
> d = d_splice_alias(inode, dentry);
> + if (IS_ERR(d)) {
> + iput(inode);
> + gfs2_glock_dq_uninit(&gh);
> + return d;
> + }
> if (file && S_ISREG(inode->i_mode))
> error = finish_open(file, dentry, gfs2_open_common, opened);
>


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