[rebase] resurrect xfs-related changes

During rebase a lot of xfs-related patches/hunks were skipped.
Need to review and resurrect them.

Skipped:

ms/xfs: convert dquot cache lru to list_lru
---
ms/xfs-convert-dquot-cache-lru-to-list_lru-fix
---
ms/xfs: fix dquot isolation hang
---

ms/list_lru: dynamically adjust node arrays

hunk in xfs_qm_init_quotainfo():
orig hunk:
@@ -858,8 +865,6 @@ xfs_qm_init_quotainfo(
        INIT_RADIX_TREE(&qinf->qi_pquota_tree, GFP_NOFS);
        mutex_init(&qinf->qi_tree_lock);

- list_lru_init(&qinf->qi_lru);
-
        /* mutex used to serialize quotaoffs */
        mutex_init(&qinf->qi_quotaofflock);
+++++++++++++++++++++++++++++++++++++++++++++++
what i did:
        mutex_init(&qinf->qi_tree_lock);

<<<<<<< HEAD
        INIT_LIST_HEAD(&qinf->qi_lru_list);
        qinf->qi_lru_count = 0;
- mutex_init(&qinf->qi_lru_lock);

=======
>>>>>>> f7f8d3d... ms/list_lru: dynamically adjust node arrays
        /* mutex used to serialize quotaoffs */
        mutex_init(&qinf->qi_quotaofflock);
+++++++++++++++++++++++++++++++++++++++++++++++

---
ms/list_lru: introduce list_lru_shrink_{count,walk}
dropped hunk in fs/xfs/xfs_qm.c
---
ms/list_lru: add helpers to isolate items
dropped hunk in fs/xfs/xfs_qm.c