"J. Bruce Fields" <bfields@xxxxxxxxxxxx> writes:
> Yesterday you passed on a report of this printk from nfsdfh.c firing:
>
> printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
> dentry);
>
> I think the dentry probably comes from the FILEID_ROOT case of:
>
> if (fileid_type == FILEID_ROOT)
> dentry = dget(exp->ex_path.dentry);
> else {
> dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
> data_left, fileid_type,
> nfsd_acceptable, exp);
> }
>
> In that case the dentry was found using ordinary filesystem lookups, so
> doesn't go through the same DISCONNECTED-clearing logic as in the case
> of lookups by filehandle.
>
> Probably they have an export root that's not a filesystem root, and the
> lookups happened in the right order?
>
> I suspect that's fine, and that the printk is just stupid, but maybe we
> should clear DISCONNECTED when possible on normal lookups. The
> following is my attempt, though I'm not sure if d_alloc is the right
> place to do this. In any case it might help confirm this is what's
> happening.
>
> So if you pass along this patch to the person who was seeing that printk
> I'd be interested in the results.
I have been reading through the dentry code for other reasons and your
patch definitely won't change anything. __d_alloc sets d_flags = 0.
Therefore d_alloc always returns with d_flags == 0.
Eric
> --b.
>
>
> commit 49fc5637ca951d2add808a695768512f8b5bd7ad
> Author: J. Bruce Fields <bfields@xxxxxxxxxx>
> Date: Thu Feb 13 14:04:43 2014 -0500
>
> dcache: clear DCACHE_DISCONNECTED on child when cleared on parent
>
> Currently DCACHE_DISCONNECTED is only cleared by the filehandle lookup
> code. That's OK, it's only the filehandle code that really cares about
> this flag. But it might be kinder to also clear DCACHE_DISCONNECTED on
> regular lookups when we notice it's appropriate.
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>
> diff --git a/fs/dcache.c b/fs/dcache.c
> index 265e0ce..c4a9478 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -1534,6 +1534,16 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
> return dentry;
> }
>
> +static void d_inherit_connected(struct dentry *dentry)
> +{
> + /*
> + * If the parent is connected, then the child is too. (But if
> + * DISCONNECTED is set, that doesn't tell us anything certain.)
> + */
> + if (!(dentry->d_parent->d_flags & DCACHE_DISCONNECTED))
> + dentry->d_flags &= ~DCACHE_DISCONNECTED;
> +}
> +
> /**
> * d_alloc - allocate a dcache entry
> * @parent: parent of entry to allocate
> @@ -1556,6 +1566,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
> */
> __dget_dlock(parent);
> dentry->d_parent = parent;
> + d_inherit_connected(dentry);
> list_add(&dentry->d_u.d_child, &parent->d_subdirs);
> spin_unlock(&parent->d_lock);
>
> --
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