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
  46  *  @{
  47  */
  48
  49 /*****************************************************************************
  50  *
  51  * Lov page operations.
  52  *
  53  */
  54
  55 static int lov_page_invariant(const struct cl_page_slice *slice)
  56 {
  57         const struct cl_page  *page = slice->cpl_page;
  58         const struct cl_page  *sub  = lov_sub_page(slice);
  59
  60         return ergo(sub != NULL,
  61                     page->cp_child == sub &&
  62                     sub->cp_parent == page &&
  63                     page->cp_state == sub->cp_state);
  64 }
  65
  66 static void lov_page_fini(const struct lu_env *env,
  67                           struct cl_page_slice *slice)
  68 {
  69         struct lov_page *lp  = cl2lov_page(slice);
  70         struct cl_page  *sub = lov_sub_page(slice);
  71
  72         LINVRNT(lov_page_invariant(slice));
  73         ENTRY;
  74
  75         if (sub != NULL) {
  76                 LASSERT(sub->cp_state == CPS_FREEING);
  77                 lu_ref_del(&sub->cp_reference, "lov", sub->cp_parent);
  78                 sub->cp_parent = NULL;
  79                 slice->cpl_page->cp_child = NULL;
  80                 cl_page_put(env, sub);
  81         }
  82         OBD_SLAB_FREE_PTR(lp, lov_page_kmem);
  83         EXIT;
  84 }
  85
  86 static int lov_page_own(const struct lu_env *env,
  87                         const struct cl_page_slice *slice, struct cl_io *io,
  88                         int nonblock)
  89 {
  90         struct lov_io     *lio = lov_env_io(env);
  91         struct lov_io_sub *sub;
  92
  93         LINVRNT(lov_page_invariant(slice));
  94         LINVRNT(!cl2lov_page(slice)->lps_invalid);
  95         ENTRY;
  96
  97         sub = lov_page_subio(env, lio, slice);
  98         if (!IS_ERR(sub)) {
  99                 lov_sub_page(slice)->cp_owner = sub->sub_io;
 100                 lov_sub_put(sub);
 101         } else
 102                 LBUG(); /* Arrgh */
 103         RETURN(0);
 104 }
 105
 106 static void lov_page_assume(const struct lu_env *env,
 107                             const struct cl_page_slice *slice, struct cl_io *io)
 108 {
 109         lov_page_own(env, slice, io, 0);
 110 }
 111
 112 static int lov_page_print(const struct lu_env *env,
 113                           const struct cl_page_slice *slice,
 114                           void *cookie, lu_printer_t printer)
 115 {
 116         struct lov_page *lp = cl2lov_page(slice);
 117
 118         return (*printer)(env, cookie, LUSTRE_LOV_NAME"-page@%p\n", lp);
 119 }
 120
 121 static const struct cl_page_operations lov_page_ops = {
 122         .cpo_fini   = lov_page_fini,
 123         .cpo_own    = lov_page_own,
 124         .cpo_assume = lov_page_assume,
 125         .cpo_print  = lov_page_print
 126 };
 127
 128 static void lov_empty_page_fini(const struct lu_env *env,
 129                                 struct cl_page_slice *slice)
 130 {
 131         struct lov_page *lp  = cl2lov_page(slice);
 132
 133         LASSERT(slice->cpl_page->cp_child == NULL);
 134         ENTRY;
 135         OBD_SLAB_FREE_PTR(lp, lov_page_kmem);
 136         EXIT;
 137 }
 138
 139 struct cl_page *lov_page_init_raid0(const struct lu_env *env,
 140                                     struct cl_object *obj, struct cl_page *page,
 141                                     cfs_page_t *vmpage)
 142 {
 143         struct lov_page   *lpg;
 144         struct lov_object *loo = cl2lov(obj);
 145         int result;
 146
 147         ENTRY;
 148         OBD_SLAB_ALLOC_PTR_GFP(lpg, lov_page_kmem, CFS_ALLOC_IO);
 149         if (lpg != NULL) {
 150                 loff_t   offset;
 151                 int      stripe;
 152                 obd_off  suboff;
 153                 struct cl_page          *subpage;
 154                 struct cl_object        *subobj;
 155                 struct lov_layout_raid0 *r0 = lov_r0(loo);
 156
 157                 offset = cl_offset(obj, page->cp_index);
 158                 stripe = lov_stripe_number(r0->lo_lsm, offset);
 159                 result = lov_stripe_offset(r0->lo_lsm, offset, stripe,
 160                                            &suboff);
 161                 LASSERT(stripe < r0->lo_nr);
 162                 LASSERT(result == 0);
 163
 164                 subobj  = lovsub2cl(r0->lo_sub[stripe]);
 165                 subpage = cl_page_find(env, subobj,
 166                                        cl_index(subobj, suboff), vmpage,
 167                                        page->cp_type);
 168                 if (!IS_ERR(subpage)) {
 169                         if (subpage->cp_parent != NULL) {
 170                                 /*
 171                                  * This is only possible when TRANSIENT page
 172                                  * is being created, and CACHEABLE sub-page
 173                                  * (attached to already existing top-page) has
 174                                  * been found. Tell cl_page_find() to use
 175                                  * existing page.
 176                                  */
 177                                 LASSERT(subpage->cp_type == CPT_CACHEABLE);
 178                                 LASSERT(page->cp_type == CPT_TRANSIENT);
 179                                 lpg->lps_invalid = 1;
 180                                 cl_page_put(env, subpage);
 181                                 /*
 182                                  * XXX This assumes that lov is in the topmost
 183                                  * cl_page.
 184                                  */
 185                                 result = PTR_ERR(cl_page_top(subpage));
 186                         } else {
 187                                 lu_ref_add(&subpage->cp_reference, "lov", page);
 188                                 subpage->cp_parent = page;
 189                                 page->cp_child = subpage;
 190                         }
 191                         cl_page_slice_add(page, &lpg->lps_cl,
 192                                           obj, &lov_page_ops);
 193                 } else
 194                         result = PTR_ERR(subpage);
 195         } else
 196                 result = -ENOMEM;
 197         RETURN(ERR_PTR(result));
 198 }
 199
 200
 201 static const struct cl_page_operations lov_empty_page_ops = {
 202         .cpo_fini   = lov_empty_page_fini,
 203         .cpo_print  = lov_page_print
 204 };
 205
 206 struct cl_page *lov_page_init_empty(const struct lu_env *env,
 207                                     struct cl_object *obj, struct cl_page *page,
 208                                     cfs_page_t *vmpage)
 209 {
 210         struct lov_page   *lpg;
 211         int result = -ENOMEM;
 212         ENTRY;
 213
 214         OBD_SLAB_ALLOC_PTR_GFP(lpg, lov_page_kmem, CFS_ALLOC_IO);
 215         if (lpg != NULL) {
 216                 void *addr;
 217                 cl_page_slice_add(page, &lpg->lps_cl,
 218                                   obj, &lov_empty_page_ops);
 219                 addr = cfs_kmap(vmpage);
 220                 memset(addr, 0, cl_page_size(obj));
 221                 cfs_kunmap(vmpage);
 222                 cl_page_export(env, page, 1);
 223                 result = 0;
 224         }
 225         RETURN(ERR_PTR(result));
 226 }
 227
 228
 229 /** @} lov */
 230