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26 * Copyright (c) 2011, 2017, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
31 * Implementation of cl_page for LOV layer.
33 * Author: Nikita Danilov <nikita.danilov@sun.com>
34 * Author: Jinshan Xiong <jinshan.xiong@intel.com>
37 #define DEBUG_SUBSYSTEM S_LOV
39 #include "lov_cl_internal.h"
45 /*****************************************************************************
47 * Lov page operations.
51 static int lov_comp_page_print(const struct lu_env *env,
52 const struct cl_page_slice *slice,
53 void *cookie, lu_printer_t printer)
55 struct lov_page *lp = cl2lov_page(slice);
57 return (*printer)(env, cookie,
58 LUSTRE_LOV_NAME"-page@%p\n", lp);
61 static const struct cl_page_operations lov_comp_page_ops = {
62 .cpo_print = lov_comp_page_print
65 int lov_page_init_composite(const struct lu_env *env, struct cl_object *obj,
66 struct cl_page *page, pgoff_t index)
68 struct lov_object *loo = cl2lov(obj);
69 struct lov_io *lio = lov_env_io(env);
70 struct cl_object *subobj;
72 struct lov_io_sub *sub;
73 struct lov_page *lpg = cl_object_page_slice(obj, page);
74 struct lov_layout_raid0 *r0;
77 bool stripe_cached = false;
84 /* Direct i/o (CPT_TRANSIENT) is split strictly to stripes, so we can
85 * cache the stripe information. Buffered i/o is differently
86 * organized, and stripe calculation isn't a significant cost for
87 * buffered i/o, so we only cache this for direct i/o.
89 stripe_cached = lio->lis_cached_entry != LIS_CACHE_ENTRY_NONE &&
90 page->cp_type == CPT_TRANSIENT;
92 offset = cl_offset(obj, index);
95 entry = lio->lis_cached_entry;
96 stripe = lio->lis_cached_stripe;
97 /* Offset can never go backwards in an i/o, so this is valid */
98 suboff = lio->lis_cached_suboff + offset - lio->lis_cached_off;
100 entry = lov_io_layout_at(lio, offset);
102 stripe = lov_stripe_number(loo->lo_lsm, entry, offset);
103 rc = lov_stripe_offset(loo->lo_lsm, entry, offset, stripe,
106 lio->lis_cached_entry = entry;
107 lio->lis_cached_stripe = stripe;
108 lio->lis_cached_off = offset;
109 lio->lis_cached_suboff = suboff;
112 if (entry < 0 || !lsm_entry_inited(loo->lo_lsm, entry)) {
113 /* non-existing layout component */
114 lov_page_init_empty(env, obj, page, index);
118 CDEBUG(D_PAGE, "offset %llu, entry %d, stripe %d, suboff %llu\n",
119 offset, entry, stripe, suboff);
121 page->cp_lov_index = lov_comp_index(entry, stripe);
122 cl_page_slice_add(page, &lpg->lps_cl, obj, &lov_comp_page_ops);
124 if (!stripe_cached) {
125 sub = lov_sub_get(env, lio, page->cp_lov_index);
127 RETURN(PTR_ERR(sub));
129 sub = lio->lis_cached_sub;
132 lio->lis_cached_sub = sub;
134 r0 = lov_r0(loo, entry);
135 LASSERT(stripe < r0->lo_nr);
137 subobj = lovsub2cl(r0->lo_sub[stripe]);
138 cl_object_for_each(o, subobj) {
139 if (o->co_ops->coo_page_init) {
140 rc = o->co_ops->coo_page_init(sub->sub_env, o, page,
141 cl_index(subobj, suboff));
150 static int lov_empty_page_print(const struct lu_env *env,
151 const struct cl_page_slice *slice,
152 void *cookie, lu_printer_t printer)
154 struct lov_page *lp = cl2lov_page(slice);
156 return (*printer)(env, cookie, LUSTRE_LOV_NAME"-page@%p, empty.\n", lp);
159 static const struct cl_page_operations lov_empty_page_ops = {
160 .cpo_print = lov_empty_page_print
163 int lov_page_init_empty(const struct lu_env *env, struct cl_object *obj,
164 struct cl_page *page, pgoff_t index)
166 struct lov_page *lpg = cl_object_page_slice(obj, page);
171 page->cp_lov_index = ~0;
172 cl_page_slice_add(page, &lpg->lps_cl, obj, &lov_empty_page_ops);
173 addr = kmap(page->cp_vmpage);
174 memset(addr, 0, cl_page_size(obj));
175 kunmap(page->cp_vmpage);
176 cl_page_export(env, page, 1);
180 int lov_page_init_foreign(const struct lu_env *env, struct cl_object *obj,
181 struct cl_page *page, pgoff_t index)
183 CDEBUG(D_PAGE, DFID" has no data\n", PFID(lu_object_fid(&obj->co_lu)));
187 bool lov_page_is_empty(const struct cl_page *page)
189 const struct cl_page_slice *slice = cl_page_at(page, &lov_device_type);
191 LASSERT(slice != NULL);
192 return slice->cpl_ops == &lov_empty_page_ops;