diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/obdclass/cl_page.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/obdclass/cl_page.c | 1605 |
1 files changed, 1605 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/obdclass/cl_page.c b/drivers/staging/lustre/lustre/obdclass/cl_page.c new file mode 100644 index 000000000000..bb9335911c34 --- /dev/null +++ b/drivers/staging/lustre/lustre/obdclass/cl_page.c @@ -0,0 +1,1605 @@ +/* + * GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see + * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + * GPL HEADER END + */ +/* + * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. + * Use is subject to license terms. + * + * Copyright (c) 2011, 2012, Intel Corporation. + */ +/* + * This file is part of Lustre, http://www.lustre.org/ + * Lustre is a trademark of Sun Microsystems, Inc. + * + * Client Lustre Page. + * + * Author: Nikita Danilov <nikita.danilov@sun.com> + */ + +#define DEBUG_SUBSYSTEM S_CLASS + +#include <linux/libcfs/libcfs.h> +#include <obd_class.h> +#include <obd_support.h> +#include <linux/list.h> + +#include <cl_object.h> +#include "cl_internal.h" + +static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg, + int radix); + +# define PASSERT(env, page, expr) \ + do { \ + if (unlikely(!(expr))) { \ + CL_PAGE_DEBUG(D_ERROR, (env), (page), #expr "\n"); \ + LASSERT(0); \ + } \ + } while (0) + +# define PINVRNT(env, page, exp) \ + ((void)sizeof(env), (void)sizeof(page), (void)sizeof !!(exp)) + +/* Disable page statistic by default due to huge performance penalty. */ +#define CS_PAGE_INC(o, item) +#define CS_PAGE_DEC(o, item) +#define CS_PAGESTATE_INC(o, state) +#define CS_PAGESTATE_DEC(o, state) + +/** + * Internal version of cl_page_top, it should be called if the page is + * known to be not freed, says with page referenced, or radix tree lock held, + * or page owned. + */ +static struct cl_page *cl_page_top_trusted(struct cl_page *page) +{ + while (page->cp_parent != NULL) + page = page->cp_parent; + return page; +} + +/** + * Internal version of cl_page_get(). + * + * This function can be used to obtain initial reference to previously + * unreferenced cached object. It can be called only if concurrent page + * reclamation is somehow prevented, e.g., by locking page radix-tree + * (cl_object_header::hdr->coh_page_guard), or by keeping a lock on a VM page, + * associated with \a page. + * + * Use with care! Not exported. + */ +static void cl_page_get_trust(struct cl_page *page) +{ + LASSERT(atomic_read(&page->cp_ref) > 0); + atomic_inc(&page->cp_ref); +} + +/** + * Returns a slice within a page, corresponding to the given layer in the + * device stack. + * + * \see cl_lock_at() + */ +static const struct cl_page_slice * +cl_page_at_trusted(const struct cl_page *page, + const struct lu_device_type *dtype) +{ + const struct cl_page_slice *slice; + ENTRY; + + page = cl_page_top_trusted((struct cl_page *)page); + do { + list_for_each_entry(slice, &page->cp_layers, cpl_linkage) { + if (slice->cpl_obj->co_lu.lo_dev->ld_type == dtype) + RETURN(slice); + } + page = page->cp_child; + } while (page != NULL); + RETURN(NULL); +} + +/** + * Returns a page with given index in the given object, or NULL if no page is + * found. Acquires a reference on \a page. + * + * Locking: called under cl_object_header::coh_page_guard spin-lock. + */ +struct cl_page *cl_page_lookup(struct cl_object_header *hdr, pgoff_t index) +{ + struct cl_page *page; + + LASSERT(spin_is_locked(&hdr->coh_page_guard)); + + page = radix_tree_lookup(&hdr->coh_tree, index); + if (page != NULL) + cl_page_get_trust(page); + return page; +} +EXPORT_SYMBOL(cl_page_lookup); + +/** + * Returns a list of pages by a given [start, end] of \a obj. + * + * \param resched If not NULL, then we give up before hogging CPU for too + * long and set *resched = 1, in that case caller should implement a retry + * logic. + * + * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely + * crucial in the face of [offset, EOF] locks. + * + * Return at least one page in @queue unless there is no covered page. + */ +int cl_page_gang_lookup(const struct lu_env *env, struct cl_object *obj, + struct cl_io *io, pgoff_t start, pgoff_t end, + cl_page_gang_cb_t cb, void *cbdata) +{ + struct cl_object_header *hdr; + struct cl_page *page; + struct cl_page **pvec; + const struct cl_page_slice *slice; + const struct lu_device_type *dtype; + pgoff_t idx; + unsigned int nr; + unsigned int i; + unsigned int j; + int res = CLP_GANG_OKAY; + int tree_lock = 1; + ENTRY; + + idx = start; + hdr = cl_object_header(obj); + pvec = cl_env_info(env)->clt_pvec; + dtype = cl_object_top(obj)->co_lu.lo_dev->ld_type; + spin_lock(&hdr->coh_page_guard); + while ((nr = radix_tree_gang_lookup(&hdr->coh_tree, (void **)pvec, + idx, CLT_PVEC_SIZE)) > 0) { + int end_of_region = 0; + idx = pvec[nr - 1]->cp_index + 1; + for (i = 0, j = 0; i < nr; ++i) { + page = pvec[i]; + pvec[i] = NULL; + + LASSERT(page->cp_type == CPT_CACHEABLE); + if (page->cp_index > end) { + end_of_region = 1; + break; + } + if (page->cp_state == CPS_FREEING) + continue; + + slice = cl_page_at_trusted(page, dtype); + /* + * Pages for lsm-less file has no underneath sub-page + * for osc, in case of ... + */ + PASSERT(env, page, slice != NULL); + + page = slice->cpl_page; + /* + * Can safely call cl_page_get_trust() under + * radix-tree spin-lock. + * + * XXX not true, because @page is from object another + * than @hdr and protected by different tree lock. + */ + cl_page_get_trust(page); + lu_ref_add_atomic(&page->cp_reference, + "gang_lookup", current); + pvec[j++] = page; + } + + /* + * Here a delicate locking dance is performed. Current thread + * holds a reference to a page, but has to own it before it + * can be placed into queue. Owning implies waiting, so + * radix-tree lock is to be released. After a wait one has to + * check that pages weren't truncated (cl_page_own() returns + * error in the latter case). + */ + spin_unlock(&hdr->coh_page_guard); + tree_lock = 0; + + for (i = 0; i < j; ++i) { + page = pvec[i]; + if (res == CLP_GANG_OKAY) + res = (*cb)(env, io, page, cbdata); + lu_ref_del(&page->cp_reference, + "gang_lookup", current); + cl_page_put(env, page); + } + if (nr < CLT_PVEC_SIZE || end_of_region) + break; + + if (res == CLP_GANG_OKAY && need_resched()) + res = CLP_GANG_RESCHED; + if (res != CLP_GANG_OKAY) + break; + + spin_lock(&hdr->coh_page_guard); + tree_lock = 1; + } + if (tree_lock) + spin_unlock(&hdr->coh_page_guard); + RETURN(res); +} +EXPORT_SYMBOL(cl_page_gang_lookup); + +static void cl_page_free(const struct lu_env *env, struct cl_page *page) +{ + struct cl_object *obj = page->cp_obj; + int pagesize = cl_object_header(obj)->coh_page_bufsize; + + PASSERT(env, page, list_empty(&page->cp_batch)); + PASSERT(env, page, page->cp_owner == NULL); + PASSERT(env, page, page->cp_req == NULL); + PASSERT(env, page, page->cp_parent == NULL); + PASSERT(env, page, page->cp_state == CPS_FREEING); + + ENTRY; + might_sleep(); + while (!list_empty(&page->cp_layers)) { + struct cl_page_slice *slice; + + slice = list_entry(page->cp_layers.next, + struct cl_page_slice, cpl_linkage); + list_del_init(page->cp_layers.next); + slice->cpl_ops->cpo_fini(env, slice); + } + CS_PAGE_DEC(obj, total); + CS_PAGESTATE_DEC(obj, page->cp_state); + lu_object_ref_del_at(&obj->co_lu, page->cp_obj_ref, "cl_page", page); + cl_object_put(env, obj); + lu_ref_fini(&page->cp_reference); + OBD_FREE(page, pagesize); + EXIT; +} + +/** + * Helper function updating page state. This is the only place in the code + * where cl_page::cp_state field is mutated. + */ +static inline void cl_page_state_set_trust(struct cl_page *page, + enum cl_page_state state) +{ + /* bypass const. */ + *(enum cl_page_state *)&page->cp_state = state; +} + +static struct cl_page *cl_page_alloc(const struct lu_env *env, + struct cl_object *o, pgoff_t ind, struct page *vmpage, + enum cl_page_type type) +{ + struct cl_page *page; + struct lu_object_header *head; + + ENTRY; + OBD_ALLOC_GFP(page, cl_object_header(o)->coh_page_bufsize, + __GFP_IO); + if (page != NULL) { + int result = 0; + atomic_set(&page->cp_ref, 1); + if (type == CPT_CACHEABLE) /* for radix tree */ + atomic_inc(&page->cp_ref); + page->cp_obj = o; + cl_object_get(o); + page->cp_obj_ref = lu_object_ref_add(&o->co_lu, "cl_page",page); + page->cp_index = ind; + cl_page_state_set_trust(page, CPS_CACHED); + page->cp_type = type; + INIT_LIST_HEAD(&page->cp_layers); + INIT_LIST_HEAD(&page->cp_batch); + INIT_LIST_HEAD(&page->cp_flight); + mutex_init(&page->cp_mutex); + lu_ref_init(&page->cp_reference); + head = o->co_lu.lo_header; + list_for_each_entry(o, &head->loh_layers, + co_lu.lo_linkage) { + if (o->co_ops->coo_page_init != NULL) { + result = o->co_ops->coo_page_init(env, o, + page, vmpage); + if (result != 0) { + cl_page_delete0(env, page, 0); + cl_page_free(env, page); + page = ERR_PTR(result); + break; + } + } + } + if (result == 0) { + CS_PAGE_INC(o, total); + CS_PAGE_INC(o, create); + CS_PAGESTATE_DEC(o, CPS_CACHED); + } + } else { + page = ERR_PTR(-ENOMEM); + } + RETURN(page); +} + +/** + * Returns a cl_page with index \a idx at the object \a o, and associated with + * the VM page \a vmpage. + * + * This is the main entry point into the cl_page caching interface. First, a + * cache (implemented as a per-object radix tree) is consulted. If page is + * found there, it is returned immediately. Otherwise new page is allocated + * and returned. In any case, additional reference to page is acquired. + * + * \see cl_object_find(), cl_lock_find() + */ +static struct cl_page *cl_page_find0(const struct lu_env *env, + struct cl_object *o, + pgoff_t idx, struct page *vmpage, + enum cl_page_type type, + struct cl_page *parent) +{ + struct cl_page *page = NULL; + struct cl_page *ghost = NULL; + struct cl_object_header *hdr; + int err; + + LASSERT(type == CPT_CACHEABLE || type == CPT_TRANSIENT); + might_sleep(); + + ENTRY; + + hdr = cl_object_header(o); + CS_PAGE_INC(o, lookup); + + CDEBUG(D_PAGE, "%lu@"DFID" %p %lx %d\n", + idx, PFID(&hdr->coh_lu.loh_fid), vmpage, vmpage->private, type); + /* fast path. */ + if (type == CPT_CACHEABLE) { + /* vmpage lock is used to protect the child/parent + * relationship */ + KLASSERT(PageLocked(vmpage)); + /* + * cl_vmpage_page() can be called here without any locks as + * + * - "vmpage" is locked (which prevents ->private from + * concurrent updates), and + * + * - "o" cannot be destroyed while current thread holds a + * reference on it. + */ + page = cl_vmpage_page(vmpage, o); + PINVRNT(env, page, + ergo(page != NULL, + cl_page_vmpage(env, page) == vmpage && + (void *)radix_tree_lookup(&hdr->coh_tree, + idx) == page)); + } + + if (page != NULL) { + CS_PAGE_INC(o, hit); + RETURN(page); + } + + /* allocate and initialize cl_page */ + page = cl_page_alloc(env, o, idx, vmpage, type); + if (IS_ERR(page)) + RETURN(page); + + if (type == CPT_TRANSIENT) { + if (parent) { + LASSERT(page->cp_parent == NULL); + page->cp_parent = parent; + parent->cp_child = page; + } + RETURN(page); + } + + /* + * XXX optimization: use radix_tree_preload() here, and change tree + * gfp mask to GFP_KERNEL in cl_object_header_init(). + */ + spin_lock(&hdr->coh_page_guard); + err = radix_tree_insert(&hdr->coh_tree, idx, page); + if (err != 0) { + ghost = page; + /* + * Noted by Jay: a lock on \a vmpage protects cl_page_find() + * from this race, but + * + * 0. it's better to have cl_page interface "locally + * consistent" so that its correctness can be reasoned + * about without appealing to the (obscure world of) VM + * locking. + * + * 1. handling this race allows ->coh_tree to remain + * consistent even when VM locking is somehow busted, + * which is very useful during diagnosing and debugging. + */ + page = ERR_PTR(err); + CL_PAGE_DEBUG(D_ERROR, env, ghost, + "fail to insert into radix tree: %d\n", err); + } else { + if (parent) { + LASSERT(page->cp_parent == NULL); + page->cp_parent = parent; + parent->cp_child = page; + } + hdr->coh_pages++; + } + spin_unlock(&hdr->coh_page_guard); + + if (unlikely(ghost != NULL)) { + cl_page_delete0(env, ghost, 0); + cl_page_free(env, ghost); + } + RETURN(page); +} + +struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *o, + pgoff_t idx, struct page *vmpage, + enum cl_page_type type) +{ + return cl_page_find0(env, o, idx, vmpage, type, NULL); +} +EXPORT_SYMBOL(cl_page_find); + + +struct cl_page *cl_page_find_sub(const struct lu_env *env, struct cl_object *o, + pgoff_t idx, struct page *vmpage, + struct cl_page *parent) +{ + return cl_page_find0(env, o, idx, vmpage, parent->cp_type, parent); +} +EXPORT_SYMBOL(cl_page_find_sub); + +static inline int cl_page_invariant(const struct cl_page *pg) +{ + struct cl_object_header *header; + struct cl_page *parent; + struct cl_page *child; + struct cl_io *owner; + + /* + * Page invariant is protected by a VM lock. + */ + LINVRNT(cl_page_is_vmlocked(NULL, pg)); + + header = cl_object_header(pg->cp_obj); + parent = pg->cp_parent; + child = pg->cp_child; + owner = pg->cp_owner; + + return cl_page_in_use(pg) && + ergo(parent != NULL, parent->cp_child == pg) && + ergo(child != NULL, child->cp_parent == pg) && + ergo(child != NULL, pg->cp_obj != child->cp_obj) && + ergo(parent != NULL, pg->cp_obj != parent->cp_obj) && + ergo(owner != NULL && parent != NULL, + parent->cp_owner == pg->cp_owner->ci_parent) && + ergo(owner != NULL && child != NULL, + child->cp_owner->ci_parent == owner) && + /* + * Either page is early in initialization (has neither child + * nor parent yet), or it is in the object radix tree. + */ + ergo(pg->cp_state < CPS_FREEING && pg->cp_type == CPT_CACHEABLE, + (void *)radix_tree_lookup(&header->coh_tree, + pg->cp_index) == pg || + (child == NULL && parent == NULL)); +} + +static void cl_page_state_set0(const struct lu_env *env, + struct cl_page *page, enum cl_page_state state) +{ + enum cl_page_state old; + + /* + * Matrix of allowed state transitions [old][new], for sanity + * checking. + */ + static const int allowed_transitions[CPS_NR][CPS_NR] = { + [CPS_CACHED] = { + [CPS_CACHED] = 0, + [CPS_OWNED] = 1, /* io finds existing cached page */ + [CPS_PAGEIN] = 0, + [CPS_PAGEOUT] = 1, /* write-out from the cache */ + [CPS_FREEING] = 1, /* eviction on the memory pressure */ + }, + [CPS_OWNED] = { + [CPS_CACHED] = 1, /* release to the cache */ + [CPS_OWNED] = 0, + [CPS_PAGEIN] = 1, /* start read immediately */ + [CPS_PAGEOUT] = 1, /* start write immediately */ + [CPS_FREEING] = 1, /* lock invalidation or truncate */ + }, + [CPS_PAGEIN] = { + [CPS_CACHED] = 1, /* io completion */ + [CPS_OWNED] = 0, + [CPS_PAGEIN] = 0, + [CPS_PAGEOUT] = 0, + [CPS_FREEING] = 0, + }, + [CPS_PAGEOUT] = { + [CPS_CACHED] = 1, /* io completion */ + [CPS_OWNED] = 0, + [CPS_PAGEIN] = 0, + [CPS_PAGEOUT] = 0, + [CPS_FREEING] = 0, + }, + [CPS_FREEING] = { + [CPS_CACHED] = 0, + [CPS_OWNED] = 0, + [CPS_PAGEIN] = 0, + [CPS_PAGEOUT] = 0, + [CPS_FREEING] = 0, + } + }; + + ENTRY; + old = page->cp_state; + PASSERT(env, page, allowed_transitions[old][state]); + CL_PAGE_HEADER(D_TRACE, env, page, "%d -> %d\n", old, state); + for (; page != NULL; page = page->cp_child) { + PASSERT(env, page, page->cp_state == old); + PASSERT(env, page, + equi(state == CPS_OWNED, page->cp_owner != NULL)); + + CS_PAGESTATE_DEC(page->cp_obj, page->cp_state); + CS_PAGESTATE_INC(page->cp_obj, state); + cl_page_state_set_trust(page, state); + } + EXIT; +} + +static void cl_page_state_set(const struct lu_env *env, + struct cl_page *page, enum cl_page_state state) +{ + cl_page_state_set0(env, page, state); +} + +/** + * Acquires an additional reference to a page. + * + * This can be called only by caller already possessing a reference to \a + * page. + * + * \see cl_object_get(), cl_lock_get(). + */ +void cl_page_get(struct cl_page *page) +{ + ENTRY; + cl_page_get_trust(page); + EXIT; +} +EXPORT_SYMBOL(cl_page_get); + +/** + * Releases a reference to a page. + * + * When last reference is released, page is returned to the cache, unless it + * is in cl_page_state::CPS_FREEING state, in which case it is immediately + * destroyed. + * + * \see cl_object_put(), cl_lock_put(). + */ +void cl_page_put(const struct lu_env *env, struct cl_page *page) +{ + PASSERT(env, page, atomic_read(&page->cp_ref) > !!page->cp_parent); + + ENTRY; + CL_PAGE_HEADER(D_TRACE, env, page, "%d\n", + atomic_read(&page->cp_ref)); + + if (atomic_dec_and_test(&page->cp_ref)) { + LASSERT(page->cp_state == CPS_FREEING); + + LASSERT(atomic_read(&page->cp_ref) == 0); + PASSERT(env, page, page->cp_owner == NULL); + PASSERT(env, page, list_empty(&page->cp_batch)); + /* + * Page is no longer reachable by other threads. Tear + * it down. + */ + cl_page_free(env, page); + } + + EXIT; +} +EXPORT_SYMBOL(cl_page_put); + +/** + * Returns a VM page associated with a given cl_page. + */ +struct page *cl_page_vmpage(const struct lu_env *env, struct cl_page *page) +{ + const struct cl_page_slice *slice; + + /* + * Find uppermost layer with ->cpo_vmpage() method, and return its + * result. + */ + page = cl_page_top(page); + do { + list_for_each_entry(slice, &page->cp_layers, cpl_linkage) { + if (slice->cpl_ops->cpo_vmpage != NULL) + RETURN(slice->cpl_ops->cpo_vmpage(env, slice)); + } + page = page->cp_child; + } while (page != NULL); + LBUG(); /* ->cpo_vmpage() has to be defined somewhere in the stack */ +} +EXPORT_SYMBOL(cl_page_vmpage); + +/** + * Returns a cl_page associated with a VM page, and given cl_object. + */ +struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj) +{ + struct cl_page *top; + struct cl_page *page; + + ENTRY; + KLASSERT(PageLocked(vmpage)); + + /* + * NOTE: absence of races and liveness of data are guaranteed by page + * lock on a "vmpage". That works because object destruction has + * bottom-to-top pass. + */ + + /* + * This loop assumes that ->private points to the top-most page. This + * can be rectified easily. + */ + top = (struct cl_page *)vmpage->private; + if (top == NULL) + RETURN(NULL); + + for (page = top; page != NULL; page = page->cp_child) { + if (cl_object_same(page->cp_obj, obj)) { + cl_page_get_trust(page); + break; + } + } + LASSERT(ergo(page, page->cp_type == CPT_CACHEABLE)); + RETURN(page); +} +EXPORT_SYMBOL(cl_vmpage_page); + +/** + * Returns the top-page for a given page. + * + * \see cl_object_top(), cl_io_top() + */ +struct cl_page *cl_page_top(struct cl_page *page) +{ + return cl_page_top_trusted(page); +} +EXPORT_SYMBOL(cl_page_top); + +const struct cl_page_slice *cl_page_at(const struct cl_page *page, + const struct lu_device_type *dtype) +{ + return cl_page_at_trusted(page, dtype); +} +EXPORT_SYMBOL(cl_page_at); + +#define CL_PAGE_OP(opname) offsetof(struct cl_page_operations, opname) + +#define CL_PAGE_INVOKE(_env, _page, _op, _proto, ...) \ +({ \ + const struct lu_env *__env = (_env); \ + struct cl_page *__page = (_page); \ + const struct cl_page_slice *__scan; \ + int __result; \ + ptrdiff_t __op = (_op); \ + int (*__method)_proto; \ + \ + __result = 0; \ + __page = cl_page_top(__page); \ + do { \ + list_for_each_entry(__scan, &__page->cp_layers, \ + cpl_linkage) { \ + __method = *(void **)((char *)__scan->cpl_ops + \ + __op); \ + if (__method != NULL) { \ + __result = (*__method)(__env, __scan, \ + ## __VA_ARGS__); \ + if (__result != 0) \ + break; \ + } \ + } \ + __page = __page->cp_child; \ + } while (__page != NULL && __result == 0); \ + if (__result > 0) \ + __result = 0; \ + __result; \ +}) + +#define CL_PAGE_INVOID(_env, _page, _op, _proto, ...) \ +do { \ + const struct lu_env *__env = (_env); \ + struct cl_page *__page = (_page); \ + const struct cl_page_slice *__scan; \ + ptrdiff_t __op = (_op); \ + void (*__method)_proto; \ + \ + __page = cl_page_top(__page); \ + do { \ + list_for_each_entry(__scan, &__page->cp_layers, \ + cpl_linkage) { \ + __method = *(void **)((char *)__scan->cpl_ops + \ + __op); \ + if (__method != NULL) \ + (*__method)(__env, __scan, \ + ## __VA_ARGS__); \ + } \ + __page = __page->cp_child; \ + } while (__page != NULL); \ +} while (0) + +#define CL_PAGE_INVOID_REVERSE(_env, _page, _op, _proto, ...) \ +do { \ + const struct lu_env *__env = (_env); \ + struct cl_page *__page = (_page); \ + const struct cl_page_slice *__scan; \ + ptrdiff_t __op = (_op); \ + void (*__method)_proto; \ + \ + /* get to the bottom page. */ \ + while (__page->cp_child != NULL) \ + __page = __page->cp_child; \ + do { \ + list_for_each_entry_reverse(__scan, &__page->cp_layers, \ + cpl_linkage) { \ + __method = *(void **)((char *)__scan->cpl_ops + \ + __op); \ + if (__method != NULL) \ + (*__method)(__env, __scan, \ + ## __VA_ARGS__); \ + } \ + __page = __page->cp_parent; \ + } while (__page != NULL); \ +} while (0) + +static int cl_page_invoke(const struct lu_env *env, + struct cl_io *io, struct cl_page *page, ptrdiff_t op) + +{ + PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj)); + ENTRY; + RETURN(CL_PAGE_INVOKE(env, page, op, + (const struct lu_env *, + const struct cl_page_slice *, struct cl_io *), + io)); +} + +static void cl_page_invoid(const struct lu_env *env, + struct cl_io *io, struct cl_page *page, ptrdiff_t op) + +{ + PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj)); + ENTRY; + CL_PAGE_INVOID(env, page, op, + (const struct lu_env *, + const struct cl_page_slice *, struct cl_io *), io); + EXIT; +} + +static void cl_page_owner_clear(struct cl_page *page) +{ + ENTRY; + for (page = cl_page_top(page); page != NULL; page = page->cp_child) { + if (page->cp_owner != NULL) { + LASSERT(page->cp_owner->ci_owned_nr > 0); + page->cp_owner->ci_owned_nr--; + page->cp_owner = NULL; + page->cp_task = NULL; + } + } + EXIT; +} + +static void cl_page_owner_set(struct cl_page *page) +{ + ENTRY; + for (page = cl_page_top(page); page != NULL; page = page->cp_child) { + LASSERT(page->cp_owner != NULL); + page->cp_owner->ci_owned_nr++; + } + EXIT; +} + +void cl_page_disown0(const struct lu_env *env, + struct cl_io *io, struct cl_page *pg) +{ + enum cl_page_state state; + + ENTRY; + state = pg->cp_state; + PINVRNT(env, pg, state == CPS_OWNED || state == CPS_FREEING); + PINVRNT(env, pg, cl_page_invariant(pg)); + cl_page_owner_clear(pg); + + if (state == CPS_OWNED) + cl_page_state_set(env, pg, CPS_CACHED); + /* + * Completion call-backs are executed in the bottom-up order, so that + * uppermost layer (llite), responsible for VFS/VM interaction runs + * last and can release locks safely. + */ + CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_disown), + (const struct lu_env *, + const struct cl_page_slice *, struct cl_io *), + io); + EXIT; +} + +/** + * returns true, iff page is owned by the given io. + */ +int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io) +{ + LINVRNT(cl_object_same(pg->cp_obj, io->ci_obj)); + ENTRY; + RETURN(pg->cp_state == CPS_OWNED && pg->cp_owner == io); +} +EXPORT_SYMBOL(cl_page_is_owned); + +/** + * Try to own a page by IO. + * + * Waits until page is in cl_page_state::CPS_CACHED state, and then switch it + * into cl_page_state::CPS_OWNED state. + * + * \pre !cl_page_is_owned(pg, io) + * \post result == 0 iff cl_page_is_owned(pg, io) + * + * \retval 0 success + * + * \retval -ve failure, e.g., page was destroyed (and landed in + * cl_page_state::CPS_FREEING instead of cl_page_state::CPS_CACHED). + * or, page was owned by another thread, or in IO. + * + * \see cl_page_disown() + * \see cl_page_operations::cpo_own() + * \see cl_page_own_try() + * \see cl_page_own + */ +static int cl_page_own0(const struct lu_env *env, struct cl_io *io, + struct cl_page *pg, int nonblock) +{ + int result; + + PINVRNT(env, pg, !cl_page_is_owned(pg, io)); + + ENTRY; + pg = cl_page_top(pg); + io = cl_io_top(io); + + if (pg->cp_state == CPS_FREEING) { + result = -ENOENT; + } else { + result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(cpo_own), + (const struct lu_env *, + const struct cl_page_slice *, + struct cl_io *, int), + io, nonblock); + if (result == 0) { + PASSERT(env, pg, pg->cp_owner == NULL); + PASSERT(env, pg, pg->cp_req == NULL); + pg->cp_owner = io; + pg->cp_task = current; + cl_page_owner_set(pg); + if (pg->cp_state != CPS_FREEING) { + cl_page_state_set(env, pg, CPS_OWNED); + } else { + cl_page_disown0(env, io, pg); + result = -ENOENT; + } + } + } + PINVRNT(env, pg, ergo(result == 0, cl_page_invariant(pg))); + RETURN(result); +} + +/** + * Own a page, might be blocked. + * + * \see cl_page_own0() + */ +int cl_page_own(const struct lu_env *env, struct cl_io *io, struct cl_page *pg) +{ + return cl_page_own0(env, io, pg, 0); +} +EXPORT_SYMBOL(cl_page_own); + +/** + * Nonblock version of cl_page_own(). + * + * \see cl_page_own0() + */ +int cl_page_own_try(const struct lu_env *env, struct cl_io *io, + struct cl_page *pg) +{ + return cl_page_own0(env, io, pg, 1); +} +EXPORT_SYMBOL(cl_page_own_try); + + +/** + * Assume page ownership. + * + * Called when page is already locked by the hosting VM. + * + * \pre !cl_page_is_owned(pg, io) + * \post cl_page_is_owned(pg, io) + * + * \see cl_page_operations::cpo_assume() + */ +void cl_page_assume(const struct lu_env *env, + struct cl_io *io, struct cl_page *pg) +{ + PINVRNT(env, pg, cl_object_same(pg->cp_obj, io->ci_obj)); + + ENTRY; + pg = cl_page_top(pg); + io = cl_io_top(io); + + cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_assume)); + PASSERT(env, pg, pg->cp_owner == NULL); + pg->cp_owner = io; + pg->cp_task = current; + cl_page_owner_set(pg); + cl_page_state_set(env, pg, CPS_OWNED); + EXIT; +} +EXPORT_SYMBOL(cl_page_assume); + +/** + * Releases page ownership without unlocking the page. + * + * Moves page into cl_page_state::CPS_CACHED without releasing a lock on the + * underlying VM page (as VM is supposed to do this itself). + * + * \pre cl_page_is_owned(pg, io) + * \post !cl_page_is_owned(pg, io) + * + * \see cl_page_assume() + */ +void cl_page_unassume(const struct lu_env *env, + struct cl_io *io, struct cl_page *pg) +{ + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + PINVRNT(env, pg, cl_page_invariant(pg)); + + ENTRY; + pg = cl_page_top(pg); + io = cl_io_top(io); + cl_page_owner_clear(pg); + cl_page_state_set(env, pg, CPS_CACHED); + CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_unassume), + (const struct lu_env *, + const struct cl_page_slice *, struct cl_io *), + io); + EXIT; +} +EXPORT_SYMBOL(cl_page_unassume); + +/** + * Releases page ownership. + * + * Moves page into cl_page_state::CPS_CACHED. + * + * \pre cl_page_is_owned(pg, io) + * \post !cl_page_is_owned(pg, io) + * + * \see cl_page_own() + * \see cl_page_operations::cpo_disown() + */ +void cl_page_disown(const struct lu_env *env, + struct cl_io *io, struct cl_page *pg) +{ + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + + ENTRY; + pg = cl_page_top(pg); + io = cl_io_top(io); + cl_page_disown0(env, io, pg); + EXIT; +} +EXPORT_SYMBOL(cl_page_disown); + +/** + * Called when page is to be removed from the object, e.g., as a result of + * truncate. + * + * Calls cl_page_operations::cpo_discard() top-to-bottom. + * + * \pre cl_page_is_owned(pg, io) + * + * \see cl_page_operations::cpo_discard() + */ +void cl_page_discard(const struct lu_env *env, + struct cl_io *io, struct cl_page *pg) +{ + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + PINVRNT(env, pg, cl_page_invariant(pg)); + + cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_discard)); +} +EXPORT_SYMBOL(cl_page_discard); + +/** + * Version of cl_page_delete() that can be called for not fully constructed + * pages, e.g,. in a error handling cl_page_find()->cl_page_delete0() + * path. Doesn't check page invariant. + */ +static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg, + int radix) +{ + struct cl_page *tmp = pg; + ENTRY; + + PASSERT(env, pg, pg == cl_page_top(pg)); + PASSERT(env, pg, pg->cp_state != CPS_FREEING); + + /* + * Severe all ways to obtain new pointers to @pg. + */ + cl_page_owner_clear(pg); + + /* + * unexport the page firstly before freeing it so that + * the page content is considered to be invalid. + * We have to do this because a CPS_FREEING cl_page may + * be NOT under the protection of a cl_lock. + * Afterwards, if this page is found by other threads, then this + * page will be forced to reread. + */ + cl_page_export(env, pg, 0); + cl_page_state_set0(env, pg, CPS_FREEING); + + CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_delete), + (const struct lu_env *, const struct cl_page_slice *)); + + if (tmp->cp_type == CPT_CACHEABLE) { + if (!radix) + /* !radix means that @pg is not yet in the radix tree, + * skip removing it. + */ + tmp = pg->cp_child; + for (; tmp != NULL; tmp = tmp->cp_child) { + void *value; + struct cl_object_header *hdr; + + hdr = cl_object_header(tmp->cp_obj); + spin_lock(&hdr->coh_page_guard); + value = radix_tree_delete(&hdr->coh_tree, + tmp->cp_index); + PASSERT(env, tmp, value == tmp); + PASSERT(env, tmp, hdr->coh_pages > 0); + hdr->coh_pages--; + spin_unlock(&hdr->coh_page_guard); + cl_page_put(env, tmp); + } + } + + EXIT; +} + +/** + * Called when a decision is made to throw page out of memory. + * + * Notifies all layers about page destruction by calling + * cl_page_operations::cpo_delete() method top-to-bottom. + * + * Moves page into cl_page_state::CPS_FREEING state (this is the only place + * where transition to this state happens). + * + * Eliminates all venues through which new references to the page can be + * obtained: + * + * - removes page from the radix trees, + * + * - breaks linkage from VM page to cl_page. + * + * Once page reaches cl_page_state::CPS_FREEING, all remaining references will + * drain after some time, at which point page will be recycled. + * + * \pre pg == cl_page_top(pg) + * \pre VM page is locked + * \post pg->cp_state == CPS_FREEING + * + * \see cl_page_operations::cpo_delete() + */ +void cl_page_delete(const struct lu_env *env, struct cl_page *pg) +{ + PINVRNT(env, pg, cl_page_invariant(pg)); + ENTRY; + cl_page_delete0(env, pg, 1); + EXIT; +} +EXPORT_SYMBOL(cl_page_delete); + +/** + * Unmaps page from user virtual memory. + * + * Calls cl_page_operations::cpo_unmap() through all layers top-to-bottom. The + * layer responsible for VM interaction has to unmap page from user space + * virtual memory. + * + * \see cl_page_operations::cpo_unmap() + */ +int cl_page_unmap(const struct lu_env *env, + struct cl_io *io, struct cl_page *pg) +{ + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + PINVRNT(env, pg, cl_page_invariant(pg)); + + return cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_unmap)); +} +EXPORT_SYMBOL(cl_page_unmap); + +/** + * Marks page up-to-date. + * + * Call cl_page_operations::cpo_export() through all layers top-to-bottom. The + * layer responsible for VM interaction has to mark/clear page as up-to-date + * by the \a uptodate argument. + * + * \see cl_page_operations::cpo_export() + */ +void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate) +{ + PINVRNT(env, pg, cl_page_invariant(pg)); + CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_export), + (const struct lu_env *, + const struct cl_page_slice *, int), uptodate); +} +EXPORT_SYMBOL(cl_page_export); + +/** + * Returns true, iff \a pg is VM locked in a suitable sense by the calling + * thread. + */ +int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg) +{ + int result; + const struct cl_page_slice *slice; + + ENTRY; + pg = cl_page_top_trusted((struct cl_page *)pg); + slice = container_of(pg->cp_layers.next, + const struct cl_page_slice, cpl_linkage); + PASSERT(env, pg, slice->cpl_ops->cpo_is_vmlocked != NULL); + /* + * Call ->cpo_is_vmlocked() directly instead of going through + * CL_PAGE_INVOKE(), because cl_page_is_vmlocked() is used by + * cl_page_invariant(). + */ + result = slice->cpl_ops->cpo_is_vmlocked(env, slice); + PASSERT(env, pg, result == -EBUSY || result == -ENODATA); + RETURN(result == -EBUSY); +} +EXPORT_SYMBOL(cl_page_is_vmlocked); + +static enum cl_page_state cl_req_type_state(enum cl_req_type crt) +{ + ENTRY; + RETURN(crt == CRT_WRITE ? CPS_PAGEOUT : CPS_PAGEIN); +} + +static void cl_page_io_start(const struct lu_env *env, + struct cl_page *pg, enum cl_req_type crt) +{ + /* + * Page is queued for IO, change its state. + */ + ENTRY; + cl_page_owner_clear(pg); + cl_page_state_set(env, pg, cl_req_type_state(crt)); + EXIT; +} + +/** + * Prepares page for immediate transfer. cl_page_operations::cpo_prep() is + * called top-to-bottom. Every layer either agrees to submit this page (by + * returning 0), or requests to omit this page (by returning -EALREADY). Layer + * handling interactions with the VM also has to inform VM that page is under + * transfer now. + */ +int cl_page_prep(const struct lu_env *env, struct cl_io *io, + struct cl_page *pg, enum cl_req_type crt) +{ + int result; + + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + PINVRNT(env, pg, cl_page_invariant(pg)); + PINVRNT(env, pg, crt < CRT_NR); + + /* + * XXX this has to be called bottom-to-top, so that llite can set up + * PG_writeback without risking other layers deciding to skip this + * page. + */ + if (crt >= CRT_NR) + return -EINVAL; + result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_prep)); + if (result == 0) + cl_page_io_start(env, pg, crt); + + KLASSERT(ergo(crt == CRT_WRITE && pg->cp_type == CPT_CACHEABLE, + equi(result == 0, + PageWriteback(cl_page_vmpage(env, pg))))); + CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result); + return result; +} +EXPORT_SYMBOL(cl_page_prep); + +/** + * Notify layers about transfer completion. + * + * Invoked by transfer sub-system (which is a part of osc) to notify layers + * that a transfer, of which this page is a part of has completed. + * + * Completion call-backs are executed in the bottom-up order, so that + * uppermost layer (llite), responsible for the VFS/VM interaction runs last + * and can release locks safely. + * + * \pre pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT + * \post pg->cp_state == CPS_CACHED + * + * \see cl_page_operations::cpo_completion() + */ +void cl_page_completion(const struct lu_env *env, + struct cl_page *pg, enum cl_req_type crt, int ioret) +{ + struct cl_sync_io *anchor = pg->cp_sync_io; + + PASSERT(env, pg, crt < CRT_NR); + /* cl_page::cp_req already cleared by the caller (osc_completion()) */ + PASSERT(env, pg, pg->cp_req == NULL); + PASSERT(env, pg, pg->cp_state == cl_req_type_state(crt)); + + ENTRY; + CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, ioret); + if (crt == CRT_READ && ioret == 0) { + PASSERT(env, pg, !(pg->cp_flags & CPF_READ_COMPLETED)); + pg->cp_flags |= CPF_READ_COMPLETED; + } + + cl_page_state_set(env, pg, CPS_CACHED); + if (crt >= CRT_NR) + return; + CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(io[crt].cpo_completion), + (const struct lu_env *, + const struct cl_page_slice *, int), ioret); + if (anchor) { + LASSERT(cl_page_is_vmlocked(env, pg)); + LASSERT(pg->cp_sync_io == anchor); + pg->cp_sync_io = NULL; + } + /* + * As page->cp_obj is pinned by a reference from page->cp_req, it is + * safe to call cl_page_put() without risking object destruction in a + * non-blocking context. + */ + cl_page_put(env, pg); + + if (anchor) + cl_sync_io_note(anchor, ioret); + + EXIT; +} +EXPORT_SYMBOL(cl_page_completion); + +/** + * Notify layers that transfer formation engine decided to yank this page from + * the cache and to make it a part of a transfer. + * + * \pre pg->cp_state == CPS_CACHED + * \post pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT + * + * \see cl_page_operations::cpo_make_ready() + */ +int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg, + enum cl_req_type crt) +{ + int result; + + PINVRNT(env, pg, crt < CRT_NR); + + ENTRY; + if (crt >= CRT_NR) + RETURN(-EINVAL); + result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(io[crt].cpo_make_ready), + (const struct lu_env *, + const struct cl_page_slice *)); + if (result == 0) { + PASSERT(env, pg, pg->cp_state == CPS_CACHED); + cl_page_io_start(env, pg, crt); + } + CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result); + RETURN(result); +} +EXPORT_SYMBOL(cl_page_make_ready); + +/** + * Notify layers that high level io decided to place this page into a cache + * for future transfer. + * + * The layer implementing transfer engine (osc) has to register this page in + * its queues. + * + * \pre cl_page_is_owned(pg, io) + * \post cl_page_is_owned(pg, io) + * + * \see cl_page_operations::cpo_cache_add() + */ +int cl_page_cache_add(const struct lu_env *env, struct cl_io *io, + struct cl_page *pg, enum cl_req_type crt) +{ + const struct cl_page_slice *scan; + int result = 0; + + PINVRNT(env, pg, crt < CRT_NR); + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + PINVRNT(env, pg, cl_page_invariant(pg)); + + ENTRY; + + if (crt >= CRT_NR) + RETURN(-EINVAL); + + list_for_each_entry(scan, &pg->cp_layers, cpl_linkage) { + if (scan->cpl_ops->io[crt].cpo_cache_add == NULL) + continue; + + result = scan->cpl_ops->io[crt].cpo_cache_add(env, scan, io); + if (result != 0) + break; + } + CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result); + RETURN(result); +} +EXPORT_SYMBOL(cl_page_cache_add); + +/** + * Called if a pge is being written back by kernel's intention. + * + * \pre cl_page_is_owned(pg, io) + * \post ergo(result == 0, pg->cp_state == CPS_PAGEOUT) + * + * \see cl_page_operations::cpo_flush() + */ +int cl_page_flush(const struct lu_env *env, struct cl_io *io, + struct cl_page *pg) +{ + int result; + + PINVRNT(env, pg, cl_page_is_owned(pg, io)); + PINVRNT(env, pg, cl_page_invariant(pg)); + + ENTRY; + + result = cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_flush)); + + CL_PAGE_HEADER(D_TRACE, env, pg, "%d\n", result); + RETURN(result); +} +EXPORT_SYMBOL(cl_page_flush); + +/** + * Checks whether page is protected by any extent lock is at least required + * mode. + * + * \return the same as in cl_page_operations::cpo_is_under_lock() method. + * \see cl_page_operations::cpo_is_under_lock() + */ +int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io, + struct cl_page *page) +{ + int rc; + + PINVRNT(env, page, cl_page_invariant(page)); + + ENTRY; + rc = CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_is_under_lock), + (const struct lu_env *, + const struct cl_page_slice *, struct cl_io *), + io); + PASSERT(env, page, rc != 0); + RETURN(rc); +} +EXPORT_SYMBOL(cl_page_is_under_lock); + +static int page_prune_cb(const struct lu_env *env, struct cl_io *io, + struct cl_page *page, void *cbdata) +{ + cl_page_own(env, io, page); + cl_page_unmap(env, io, page); + cl_page_discard(env, io, page); + cl_page_disown(env, io, page); + return CLP_GANG_OKAY; +} + +/** + * Purges all cached pages belonging to the object \a obj. + */ +int cl_pages_prune(const struct lu_env *env, struct cl_object *clobj) +{ + struct cl_thread_info *info; + struct cl_object *obj = cl_object_top(clobj); + struct cl_io *io; + int result; + + ENTRY; + info = cl_env_info(env); + io = &info->clt_io; + + /* + * initialize the io. This is ugly since we never do IO in this + * function, we just make cl_page_list functions happy. -jay + */ + io->ci_obj = obj; + io->ci_ignore_layout = 1; + result = cl_io_init(env, io, CIT_MISC, obj); + if (result != 0) { + cl_io_fini(env, io); + RETURN(io->ci_result); + } + + do { + result = cl_page_gang_lookup(env, obj, io, 0, CL_PAGE_EOF, + page_prune_cb, NULL); + if (result == CLP_GANG_RESCHED) + cond_resched(); + } while (result != CLP_GANG_OKAY); + + cl_io_fini(env, io); + RETURN(result); +} +EXPORT_SYMBOL(cl_pages_prune); + +/** + * Tells transfer engine that only part of a page is to be transmitted. + * + * \see cl_page_operations::cpo_clip() + */ +void cl_page_clip(const struct lu_env *env, struct cl_page *pg, + int from, int to) +{ + PINVRNT(env, pg, cl_page_invariant(pg)); + + CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", from, to); + CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_clip), + (const struct lu_env *, + const struct cl_page_slice *,int, int), + from, to); +} +EXPORT_SYMBOL(cl_page_clip); + +/** + * Prints human readable representation of \a pg to the \a f. + */ +void cl_page_header_print(const struct lu_env *env, void *cookie, + lu_printer_t printer, const struct cl_page *pg) +{ + (*printer)(env, cookie, + "page@%p[%d %p:%lu ^%p_%p %d %d %d %p %p %#x]\n", + pg, atomic_read(&pg->cp_ref), pg->cp_obj, + pg->cp_index, pg->cp_parent, pg->cp_child, + pg->cp_state, pg->cp_error, pg->cp_type, + pg->cp_owner, pg->cp_req, pg->cp_flags); +} +EXPORT_SYMBOL(cl_page_header_print); + +/** + * Prints human readable representation of \a pg to the \a f. + */ +void cl_page_print(const struct lu_env *env, void *cookie, + lu_printer_t printer, const struct cl_page *pg) +{ + struct cl_page *scan; + + for (scan = cl_page_top((struct cl_page *)pg); + scan != NULL; scan = scan->cp_child) + cl_page_header_print(env, cookie, printer, scan); + CL_PAGE_INVOKE(env, (struct cl_page *)pg, CL_PAGE_OP(cpo_print), + (const struct lu_env *env, + const struct cl_page_slice *slice, + void *cookie, lu_printer_t p), cookie, printer); + (*printer)(env, cookie, "end page@%p\n", pg); +} +EXPORT_SYMBOL(cl_page_print); + +/** + * Cancel a page which is still in a transfer. + */ +int cl_page_cancel(const struct lu_env *env, struct cl_page *page) +{ + return CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_cancel), + (const struct lu_env *, + const struct cl_page_slice *)); +} +EXPORT_SYMBOL(cl_page_cancel); + +/** + * Converts a byte offset within object \a obj into a page index. + */ +loff_t cl_offset(const struct cl_object *obj, pgoff_t idx) +{ + /* + * XXX for now. + */ + return (loff_t)idx << PAGE_CACHE_SHIFT; +} +EXPORT_SYMBOL(cl_offset); + +/** + * Converts a page index into a byte offset within object \a obj. + */ +pgoff_t cl_index(const struct cl_object *obj, loff_t offset) +{ + /* + * XXX for now. + */ + return offset >> PAGE_CACHE_SHIFT; +} +EXPORT_SYMBOL(cl_index); + +int cl_page_size(const struct cl_object *obj) +{ + return 1 << PAGE_CACHE_SHIFT; +} +EXPORT_SYMBOL(cl_page_size); + +/** + * Adds page slice to the compound page. + * + * This is called by cl_object_operations::coo_page_init() methods to add a + * per-layer state to the page. New state is added at the end of + * cl_page::cp_layers list, that is, it is at the bottom of the stack. + * + * \see cl_lock_slice_add(), cl_req_slice_add(), cl_io_slice_add() + */ +void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice, + struct cl_object *obj, + const struct cl_page_operations *ops) +{ + ENTRY; + list_add_tail(&slice->cpl_linkage, &page->cp_layers); + slice->cpl_obj = obj; + slice->cpl_ops = ops; + slice->cpl_page = page; + EXIT; +} +EXPORT_SYMBOL(cl_page_slice_add); + +int cl_page_init(void) +{ + return 0; +} + +void cl_page_fini(void) +{ +} |