On Thu, 2017-11-30 at 15:53 +0800, Yan, Zheng wrote:
> d_prune_aliases() does not prune dentry that has non-zero reference
> count. If we want trim_caps() to trim 'N' caps, the first 'N' inodes
> in session->s_caps are all directories with child dentry, trim_caps()
> can fail to trim anything.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> ---
> fs/ceph/mds_client.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 80339e278ad8..da181acd4a61 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -1490,16 +1490,20 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
> if ((used | wanted) & ~oissued & mine)
> goto out; /* we need these caps */
>
> - session->s_trim_caps--;
> if (oissued) {
> /* we aren't the only cap.. just remove us */
> __ceph_remove_cap(cap, true);
> + session->s_trim_caps--;
> } else {
> + int refs;
> /* try dropping referring dentries */
> spin_unlock(&ci->i_ceph_lock);
> d_prune_aliases(inode);
> + refs = atomic_read(&inode->i_count);
> + if (refs == 1)
> + session->s_trim_caps--;
> dout("trim_caps_cb %p cap %p pruned, count now %d\n",
> - inode, cap, atomic_read(&inode->i_count));
> + inode, cap, refs);
> return 0;
> }
>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>