On Tue 14-04-20 23:45:21, ira.weiny@xxxxxxxxx wrote:
> From: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> DCACHE_DONTCACHE indicates a dentry should not be cached on final
> dput().
>
> Also add a helper function which will flag I_DONTCACHE as well ad
> DCACHE_DONTCACHE on all dentries point to a specified inode.
I think this sentence needs more work :). Like: Also add a helper function
which will mark the inode with I_DONTCACHE flag and also mark all dentries
pointing to a specified inode as DCACHE_DONTCACHE.
>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> ---
> Changes from V7:
> new patch
> ---
> fs/dcache.c | 4 ++++
> fs/inode.c | 15 +++++++++++++++
> include/linux/dcache.h | 2 ++
> include/linux/fs.h | 1 +
> 4 files changed, 22 insertions(+)
...
> diff --git a/fs/inode.c b/fs/inode.c
> index 93d9252a00ab..b8b1917a324e 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1526,6 +1526,21 @@ int generic_delete_inode(struct inode *inode)
> }
> EXPORT_SYMBOL(generic_delete_inode);
>
> +void flag_inode_dontcache(struct inode *inode)
mark_inode_dontcache?
> +{
> + struct dentry *dent;
This is really nitpicking but dentry variables are usually called 'de' or
'dentry' :)
> +
> + rcu_read_lock();
I don't think this list is safe to traverse under RCU. E.g.
dentry_unlink_inode() does hlist_del_init(&dentry->d_u.d_alias). Usually,
we traverse this list under inode->i_lock protection AFAICS.
Honza
> + hlist_for_each_entry(dent, &inode->i_dentry, d_u.d_alias) {
> + spin_lock(&dent->d_lock);
> + dent->d_flags |= DCACHE_DONTCACHE;
> + spin_unlock(&dent->d_lock);
> + }
> + rcu_read_unlock();
> + inode->i_state |= I_DONTCACHE;
> +}
> +EXPORT_SYMBOL(flag_inode_dontcache);
> +
> /*
> * Called when we're dropping the last reference
> * to an inode.
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
