lustre/lov/lov_page.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see
  20  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  30  * Use is subject to license terms.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * Implementation of cl_page for LOV layer.
  37  *
  38  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_LOV
  42
  43 #include "lov_cl_internal.h"
  44
  45 /** \addtogroup lov lov @{ */
  46
  47 /*****************************************************************************
  48  *
  49  * Lov page operations.
  50  *
  51  */
  52
  53 static int lov_page_invariant(const struct cl_page_slice *slice)
  54 {
  55         const struct cl_page  *page = slice->cpl_page;
  56         const struct cl_page  *sub  = lov_sub_page(slice);
  57
  58         return ergo(sub != NULL,
  59                     page->cp_child == sub &&
  60                     sub->cp_parent == page &&
  61                     page->cp_state == sub->cp_state);
  62 }
  63
  64 static void lov_page_fini(const struct lu_env *env,
  65                           struct cl_page_slice *slice)
  66 {
  67         struct lov_page *lp  = cl2lov_page(slice);
  68         struct cl_page  *sub = lov_sub_page(slice);
  69
  70         LINVRNT(lov_page_invariant(slice));
  71         ENTRY;
  72
  73         if (sub != NULL) {
  74                 LASSERT(sub->cp_state == CPS_FREEING);
  75                 lu_ref_del(&sub->cp_reference, "lov", sub->cp_parent);
  76                 sub->cp_parent = NULL;
  77                 slice->cpl_page->cp_child = NULL;
  78                 cl_page_put(env, sub);
  79         }
  80         OBD_SLAB_FREE_PTR(lp, lov_page_kmem);
  81         EXIT;
  82 }
  83
  84 static int lov_page_own(const struct lu_env *env,
  85                         const struct cl_page_slice *slice, struct cl_io *io,
  86                         int nonblock)
  87 {
  88         struct lov_io     *lio = lov_env_io(env);
  89         struct lov_io_sub *sub;
  90
  91         LINVRNT(lov_page_invariant(slice));
  92         LINVRNT(!cl2lov_page(slice)->lps_invalid);
  93         ENTRY;
  94
  95         sub = lov_page_subio(env, lio, slice);
  96         if (!IS_ERR(sub)) {
  97                 lov_sub_page(slice)->cp_owner = sub->sub_io;
  98                 lov_sub_put(sub);
  99         } else
 100                 LBUG(); /* Arrgh */
 101         RETURN(0);
 102 }
 103
 104 static void lov_page_assume(const struct lu_env *env,
 105                             const struct cl_page_slice *slice, struct cl_io *io)
 106 {
 107         lov_page_own(env, slice, io, 0);
 108 }
 109
 110 static int lov_page_print(const struct lu_env *env,
 111                           const struct cl_page_slice *slice,
 112                           void *cookie, lu_printer_t printer)
 113 {
 114         struct lov_page *lp = cl2lov_page(slice);
 115
 116         return (*printer)(env, cookie, LUSTRE_LOV_NAME"-page@%p\n", lp);
 117 }
 118
 119 static const struct cl_page_operations lov_page_ops = {
 120         .cpo_fini   = lov_page_fini,
 121         .cpo_own    = lov_page_own,
 122         .cpo_assume = lov_page_assume,
 123         .cpo_print  = lov_page_print
 124 };
 125
 126 static void lov_empty_page_fini(const struct lu_env *env,
 127                                 struct cl_page_slice *slice)
 128 {
 129         struct lov_page *lp  = cl2lov_page(slice);
 130
 131         LASSERT(slice->cpl_page->cp_child == NULL);
 132         ENTRY;
 133         OBD_SLAB_FREE_PTR(lp, lov_page_kmem);
 134         EXIT;
 135 }
 136
 137 struct cl_page *lov_page_init_raid0(const struct lu_env *env,
 138                                     struct cl_object *obj, struct cl_page *page,
 139                                     cfs_page_t *vmpage)
 140 {
 141         struct lov_page   *lpg;
 142         struct lov_object *loo = cl2lov(obj);
 143         int result;
 144
 145         ENTRY;
 146         OBD_SLAB_ALLOC_PTR_GFP(lpg, lov_page_kmem, CFS_ALLOC_IO);
 147         if (lpg != NULL) {
 148                 loff_t   offset;
 149                 int      stripe;
 150                 obd_off  suboff;
 151                 struct cl_page          *subpage;
 152                 struct cl_object        *subobj;
 153                 struct lov_layout_raid0 *r0 = lov_r0(loo);
 154
 155                 offset = cl_offset(obj, page->cp_index);
 156                 stripe = lov_stripe_number(r0->lo_lsm, offset);
 157                 result = lov_stripe_offset(r0->lo_lsm, offset, stripe,
 158                                            &suboff);
 159                 LASSERT(stripe < r0->lo_nr);
 160                 LASSERT(result == 0);
 161
 162                 subobj  = lovsub2cl(r0->lo_sub[stripe]);
 163                 subpage = cl_page_find(env, subobj,
 164                                        cl_index(subobj, suboff), vmpage,
 165                                        page->cp_type);
 166                 if (!IS_ERR(subpage)) {
 167                         if (subpage->cp_parent != NULL) {
 168                                 /*
 169                                  * This is only possible when TRANSIENT page
 170                                  * is being created, and CACHEABLE sub-page
 171                                  * (attached to already existing top-page) has
 172                                  * been found. Tell cl_page_find() to use
 173                                  * existing page.
 174                                  */
 175                                 LASSERT(subpage->cp_type == CPT_CACHEABLE);
 176                                 LASSERT(page->cp_type == CPT_TRANSIENT);
 177                                 lpg->lps_invalid = 1;
 178                                 cl_page_put(env, subpage);
 179                                 /*
 180                                  * XXX This assumes that lov is in the topmost
 181                                  * cl_page.
 182                                  */
 183                                 result = PTR_ERR(cl_page_top(subpage));
 184                         } else {
 185                                 lu_ref_add(&subpage->cp_reference, "lov", page);
 186                                 subpage->cp_parent = page;
 187                                 page->cp_child = subpage;
 188                         }
 189                         cl_page_slice_add(page, &lpg->lps_cl,
 190                                           obj, &lov_page_ops);
 191                 } else
 192                         result = PTR_ERR(subpage);
 193         } else
 194                 result = -ENOMEM;
 195         RETURN(ERR_PTR(result));
 196 }
 197
 198
 199 static const struct cl_page_operations lov_empty_page_ops = {
 200         .cpo_fini   = lov_empty_page_fini,
 201         .cpo_print  = lov_page_print
 202 };
 203
 204 struct cl_page *lov_page_init_empty(const struct lu_env *env,
 205                                     struct cl_object *obj, struct cl_page *page,
 206                                     cfs_page_t *vmpage)
 207 {
 208         struct lov_page   *lpg;
 209         int result = -ENOMEM;
 210         ENTRY;
 211
 212         OBD_SLAB_ALLOC_PTR_GFP(lpg, lov_page_kmem, CFS_ALLOC_IO);
 213         if (lpg != NULL) {
 214                 void *addr;
 215                 cl_page_slice_add(page, &lpg->lps_cl,
 216                                   obj, &lov_empty_page_ops);
 217                 addr = cfs_kmap(vmpage);
 218                 memset(addr, 0, cl_page_size(obj));
 219                 cfs_kunmap(vmpage);
 220                 cl_page_export(env, page, 1);
 221                 result = 0;
 222         }
 223         RETURN(ERR_PTR(result));
 224 }
 225
 226
 227 /** @} lov */
 228