-}
-
-#ifdef ZNODE_STATS
-static struct {
- uint64_t zms_zfsvfs_invalid;
- uint64_t zms_zfsvfs_unmounted;
- uint64_t zms_zfsvfs_recheck_invalid;
- uint64_t zms_obj_held;
- uint64_t zms_vnode_locked;
- uint64_t zms_not_only_dnlc;
-} znode_move_stats;
-#endif /* ZNODE_STATS */
-
-static void
-zfs_znode_move_impl(znode_t *ozp, znode_t *nzp)
-{
- vnode_t *vp;
-
- /* Copy fields. */
- nzp->z_zfsvfs = ozp->z_zfsvfs;
-
- /* Swap vnodes. */
- vp = nzp->z_vnode;
- nzp->z_vnode = ozp->z_vnode;
- ozp->z_vnode = vp; /* let destructor free the overwritten vnode */
- ZTOV(ozp)->v_data = ozp;
- ZTOV(nzp)->v_data = nzp;
-
- nzp->z_id = ozp->z_id;
- ASSERT(ozp->z_dirlocks == NULL); /* znode not in use */
- ASSERT(avl_numnodes(&ozp->z_range_avl) == 0);
- nzp->z_unlinked = ozp->z_unlinked;
- nzp->z_atime_dirty = ozp->z_atime_dirty;
- nzp->z_zn_prefetch = ozp->z_zn_prefetch;
- nzp->z_blksz = ozp->z_blksz;
- nzp->z_seq = ozp->z_seq;
- nzp->z_mapcnt = ozp->z_mapcnt;
- nzp->z_last_itx = ozp->z_last_itx;
- nzp->z_gen = ozp->z_gen;
- nzp->z_sync_cnt = ozp->z_sync_cnt;
- nzp->z_phys = ozp->z_phys;
- nzp->z_dbuf = ozp->z_dbuf;
-
- /* Update back pointers. */
- (void) dmu_buf_update_user(nzp->z_dbuf, ozp, nzp, &nzp->z_phys,
- znode_evict_error);
-
- /*
- * Invalidate the original znode by clearing fields that provide a
- * pointer back to the znode. Set the low bit of the vfs pointer to
- * ensure that zfs_znode_move() recognizes the znode as invalid in any
- * subsequent callback.
- */
- ozp->z_dbuf = NULL;
- POINTER_INVALIDATE(&ozp->z_zfsvfs);
-}
-
-/*
- * Wrapper function for ZFS_ENTER that returns 0 if successful and otherwise
- * returns a non-zero error code.
- */
-static int
-zfs_enter(zfsvfs_t *zfsvfs)
-{
- ZFS_ENTER(zfsvfs);
- return (0);
-}
-
-/*ARGSUSED*/
-static kmem_cbrc_t
-zfs_znode_move(void *buf, void *newbuf, size_t size, void *arg)
-{
- znode_t *ozp = buf, *nzp = newbuf;
- zfsvfs_t *zfsvfs;
- vnode_t *vp;
-
- /*
- * The znode is on the file system's list of known znodes if the vfs
- * pointer is valid. We set the low bit of the vfs pointer when freeing
- * the znode to invalidate it, and the memory patterns written by kmem
- * (baddcafe and deadbeef) set at least one of the two low bits. A newly
- * created znode sets the vfs pointer last of all to indicate that the
- * znode is known and in a valid state to be moved by this function.
- */
- zfsvfs = ozp->z_zfsvfs;
- if (!POINTER_IS_VALID(zfsvfs)) {
- ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_invalid);
- return (KMEM_CBRC_DONT_KNOW);
- }
-
- /*
- * Ensure that the filesystem is not unmounted during the move.
- */
- if (zfs_enter(zfsvfs) != 0) { /* ZFS_ENTER */
- ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_unmounted);
- return (KMEM_CBRC_DONT_KNOW);
- }
-
- mutex_enter(&zfsvfs->z_znodes_lock);
- /*
- * Recheck the vfs pointer in case the znode was removed just before
- * acquiring the lock.
- */
- if (zfsvfs != ozp->z_zfsvfs) {
- mutex_exit(&zfsvfs->z_znodes_lock);
- ZFS_EXIT(zfsvfs);
- ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_recheck_invalid);
- return (KMEM_CBRC_DONT_KNOW);
- }
-
- /*
- * At this point we know that as long as we hold z_znodes_lock, the
- * znode cannot be freed and fields within the znode can be safely
- * accessed. Now, prevent a race with zfs_zget().
- */
- if (ZFS_OBJ_HOLD_TRYENTER(zfsvfs, ozp->z_id) == 0) {
- mutex_exit(&zfsvfs->z_znodes_lock);
- ZFS_EXIT(zfsvfs);
- ZNODE_STAT_ADD(znode_move_stats.zms_obj_held);
- return (KMEM_CBRC_LATER);
- }
-
- vp = ZTOV(ozp);
- if (mutex_tryenter(&vp->v_lock) == 0) {
- ZFS_OBJ_HOLD_EXIT(zfsvfs, ozp->z_id);
- mutex_exit(&zfsvfs->z_znodes_lock);
- ZFS_EXIT(zfsvfs);
- ZNODE_STAT_ADD(znode_move_stats.zms_vnode_locked);
- return (KMEM_CBRC_LATER);
- }
-
- /* Only move znodes that are referenced _only_ by the DNLC. */
- if (vp->v_count != 1 || !vn_in_dnlc(vp)) {
- mutex_exit(&vp->v_lock);
- ZFS_OBJ_HOLD_EXIT(zfsvfs, ozp->z_id);
- mutex_exit(&zfsvfs->z_znodes_lock);
- ZFS_EXIT(zfsvfs);
- ZNODE_STAT_ADD(znode_move_stats.zms_not_only_dnlc);
- return (KMEM_CBRC_LATER);
- }
-
- /*
- * The znode is known and in a valid state to move. We're holding the
- * locks needed to execute the critical section.
- */
- zfs_znode_move_impl(ozp, nzp);
- mutex_exit(&vp->v_lock);
- ZFS_OBJ_HOLD_EXIT(zfsvfs, ozp->z_id);
-
- list_link_replace(&ozp->z_link_node, &nzp->z_link_node);
- mutex_exit(&zfsvfs->z_znodes_lock);
- ZFS_EXIT(zfsvfs);
-
- return (KMEM_CBRC_YES);