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Diffstat (limited to 'drivers/staging/lustre/lustre/include/cl_object.h')
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diff --git a/drivers/staging/lustre/lustre/include/cl_object.h b/drivers/staging/lustre/lustre/include/cl_object.h deleted file mode 100644 index 341a145c3331..000000000000 --- a/drivers/staging/lustre/lustre/include/cl_object.h +++ /dev/null @@ -1,2463 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * 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.gnu.org/licenses/gpl-2.0.html - * - * GPL HEADER END - */ -/* - * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. - * Use is subject to license terms. - * - * Copyright (c) 2011, 2015, Intel Corporation. - */ -/* - * This file is part of Lustre, http://www.lustre.org/ - * Lustre is a trademark of Sun Microsystems, Inc. - */ -#ifndef _LUSTRE_CL_OBJECT_H -#define _LUSTRE_CL_OBJECT_H - -/** \defgroup clio clio - * - * Client objects implement io operations and cache pages. - * - * Examples: lov and osc are implementations of cl interface. - * - * Big Theory Statement. - * - * Layered objects. - * - * Client implementation is based on the following data-types: - * - * - cl_object - * - * - cl_page - * - * - cl_lock represents an extent lock on an object. - * - * - cl_io represents high-level i/o activity such as whole read/write - * system call, or write-out of pages from under the lock being - * canceled. cl_io has sub-ios that can be stopped and resumed - * independently, thus achieving high degree of transfer - * parallelism. Single cl_io can be advanced forward by - * the multiple threads (although in the most usual case of - * read/write system call it is associated with the single user - * thread, that issued the system call). - * - * Terminology - * - * - to avoid confusion high-level I/O operation like read or write system - * call is referred to as "an io", whereas low-level I/O operation, like - * RPC, is referred to as "a transfer" - * - * - "generic code" means generic (not file system specific) code in the - * hosting environment. "cl-code" means code (mostly in cl_*.c files) that - * is not layer specific. - * - * Locking. - * - * - i_mutex - * - PG_locked - * - cl_object_header::coh_page_guard - * - lu_site::ls_guard - * - * See the top comment in cl_object.c for the description of overall locking and - * reference-counting design. - * - * See comments below for the description of i/o, page, and dlm-locking - * design. - * - * @{ - */ - -/* - * super-class definitions. - */ -#include <lu_object.h> -#include <lustre_compat.h> -#include <linux/atomic.h> -#include <linux/mutex.h> -#include <linux/radix-tree.h> -#include <linux/spinlock.h> -#include <linux/wait.h> - -struct inode; - -struct cl_device; - -struct cl_object; - -struct cl_page; -struct cl_page_slice; -struct cl_lock; -struct cl_lock_slice; - -struct cl_lock_operations; -struct cl_page_operations; - -struct cl_io; -struct cl_io_slice; - -struct cl_req_attr; - -/** - * Device in the client stack. - * - * \see vvp_device, lov_device, lovsub_device, osc_device - */ -struct cl_device { - /** Super-class. */ - struct lu_device cd_lu_dev; -}; - -/** \addtogroup cl_object cl_object - * @{ - */ -/** - * "Data attributes" of cl_object. Data attributes can be updated - * independently for a sub-object, and top-object's attributes are calculated - * from sub-objects' ones. - */ -struct cl_attr { - /** Object size, in bytes */ - loff_t cat_size; - /** - * Known minimal size, in bytes. - * - * This is only valid when at least one DLM lock is held. - */ - loff_t cat_kms; - /** Modification time. Measured in seconds since epoch. */ - time64_t cat_mtime; - /** Access time. Measured in seconds since epoch. */ - time64_t cat_atime; - /** Change time. Measured in seconds since epoch. */ - time64_t cat_ctime; - /** - * Blocks allocated to this cl_object on the server file system. - * - * \todo XXX An interface for block size is needed. - */ - __u64 cat_blocks; - /** - * User identifier for quota purposes. - */ - uid_t cat_uid; - /** - * Group identifier for quota purposes. - */ - gid_t cat_gid; - - /* nlink of the directory */ - __u64 cat_nlink; -}; - -/** - * Fields in cl_attr that are being set. - */ -enum cl_attr_valid { - CAT_SIZE = 1 << 0, - CAT_KMS = 1 << 1, - CAT_MTIME = 1 << 3, - CAT_ATIME = 1 << 4, - CAT_CTIME = 1 << 5, - CAT_BLOCKS = 1 << 6, - CAT_UID = 1 << 7, - CAT_GID = 1 << 8 -}; - -/** - * Sub-class of lu_object with methods common for objects on the client - * stacks. - * - * cl_object: represents a regular file system object, both a file and a - * stripe. cl_object is based on lu_object: it is identified by a fid, - * layered, cached, hashed, and lrued. Important distinction with the server - * side, where md_object and dt_object are used, is that cl_object "fans out" - * at the lov/sns level: depending on the file layout, single file is - * represented as a set of "sub-objects" (stripes). At the implementation - * level, struct lov_object contains an array of cl_objects. Each sub-object - * is a full-fledged cl_object, having its fid, living in the lru and hash - * table. - * - * This leads to the next important difference with the server side: on the - * client, it's quite usual to have objects with the different sequence of - * layers. For example, typical top-object is composed of the following - * layers: - * - * - vvp - * - lov - * - * whereas its sub-objects are composed of - * - * - lovsub - * - osc - * - * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep - * track of the object-subobject relationship. - * - * Sub-objects are not cached independently: when top-object is about to - * be discarded from the memory, all its sub-objects are torn-down and - * destroyed too. - * - * \see vvp_object, lov_object, lovsub_object, osc_object - */ -struct cl_object { - /** super class */ - struct lu_object co_lu; - /** per-object-layer operations */ - const struct cl_object_operations *co_ops; - /** offset of page slice in cl_page buffer */ - int co_slice_off; -}; - -/** - * Description of the client object configuration. This is used for the - * creation of a new client object that is identified by a more state than - * fid. - */ -struct cl_object_conf { - /** Super-class. */ - struct lu_object_conf coc_lu; - union { - /** - * Object layout. This is consumed by lov. - */ - struct lu_buf coc_layout; - /** - * Description of particular stripe location in the - * cluster. This is consumed by osc. - */ - struct lov_oinfo *coc_oinfo; - } u; - /** - * VFS inode. This is consumed by vvp. - */ - struct inode *coc_inode; - /** - * Layout lock handle. - */ - struct ldlm_lock *coc_lock; - /** - * Operation to handle layout, OBJECT_CONF_XYZ. - */ - int coc_opc; -}; - -enum { - /** configure layout, set up a new stripe, must be called while - * holding layout lock. - */ - OBJECT_CONF_SET = 0, - /** invalidate the current stripe configuration due to losing - * layout lock. - */ - OBJECT_CONF_INVALIDATE = 1, - /** wait for old layout to go away so that new layout can be set up. */ - OBJECT_CONF_WAIT = 2 -}; - -enum { - CL_LAYOUT_GEN_NONE = (u32)-2, /* layout lock was cancelled */ - CL_LAYOUT_GEN_EMPTY = (u32)-1, /* for empty layout */ -}; - -struct cl_layout { - /** the buffer to return the layout in lov_mds_md format. */ - struct lu_buf cl_buf; - /** size of layout in lov_mds_md format. */ - size_t cl_size; - /** Layout generation. */ - u32 cl_layout_gen; -}; - -/** - * Operations implemented for each cl object layer. - * - * \see vvp_ops, lov_ops, lovsub_ops, osc_ops - */ -struct cl_object_operations { - /** - * Initialize page slice for this layer. Called top-to-bottom through - * every object layer when a new cl_page is instantiated. Layer - * keeping private per-page data, or requiring its own page operations - * vector should allocate these data here, and attach then to the page - * by calling cl_page_slice_add(). \a vmpage is locked (in the VM - * sense). Optional. - * - * \retval NULL success. - * - * \retval ERR_PTR(errno) failure code. - * - * \retval valid-pointer pointer to already existing referenced page - * to be used instead of newly created. - */ - int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj, - struct cl_page *page, pgoff_t index); - /** - * Initialize lock slice for this layer. Called top-to-bottom through - * every object layer when a new cl_lock is instantiated. Layer - * keeping private per-lock data, or requiring its own lock operations - * vector should allocate these data here, and attach then to the lock - * by calling cl_lock_slice_add(). Mandatory. - */ - int (*coo_lock_init)(const struct lu_env *env, - struct cl_object *obj, struct cl_lock *lock, - const struct cl_io *io); - /** - * Initialize io state for a given layer. - * - * called top-to-bottom once per io existence to initialize io - * state. If layer wants to keep some state for this type of io, it - * has to embed struct cl_io_slice in lu_env::le_ses, and register - * slice with cl_io_slice_add(). It is guaranteed that all threads - * participating in this io share the same session. - */ - int (*coo_io_init)(const struct lu_env *env, - struct cl_object *obj, struct cl_io *io); - /** - * Fill portion of \a attr that this layer controls. This method is - * called top-to-bottom through all object layers. - * - * \pre cl_object_header::coh_attr_guard of the top-object is locked. - * - * \return 0: to continue - * \return +ve: to stop iterating through layers (but 0 is returned - * from enclosing cl_object_attr_get()) - * \return -ve: to signal error - */ - int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj, - struct cl_attr *attr); - /** - * Update attributes. - * - * \a valid is a bitmask composed from enum #cl_attr_valid, and - * indicating what attributes are to be set. - * - * \pre cl_object_header::coh_attr_guard of the top-object is locked. - * - * \return the same convention as for - * cl_object_operations::coo_attr_get() is used. - */ - int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj, - const struct cl_attr *attr, unsigned int valid); - /** - * Update object configuration. Called top-to-bottom to modify object - * configuration. - * - * XXX error conditions and handling. - */ - int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj, - const struct cl_object_conf *conf); - /** - * Glimpse ast. Executed when glimpse ast arrives for a lock on this - * object. Layers are supposed to fill parts of \a lvb that will be - * shipped to the glimpse originator as a glimpse result. - * - * \see vvp_object_glimpse(), lovsub_object_glimpse(), - * \see osc_object_glimpse() - */ - int (*coo_glimpse)(const struct lu_env *env, - const struct cl_object *obj, struct ost_lvb *lvb); - /** - * Object prune method. Called when the layout is going to change on - * this object, therefore each layer has to clean up their cache, - * mainly pages and locks. - */ - int (*coo_prune)(const struct lu_env *env, struct cl_object *obj); - /** - * Object getstripe method. - */ - int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj, - struct lov_user_md __user *lum); - /** - * Get FIEMAP mapping from the object. - */ - int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj, - struct ll_fiemap_info_key *fmkey, - struct fiemap *fiemap, size_t *buflen); - /** - * Get layout and generation of the object. - */ - int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj, - struct cl_layout *layout); - /** - * Get maximum size of the object. - */ - loff_t (*coo_maxbytes)(struct cl_object *obj); - /** - * Set request attributes. - */ - void (*coo_req_attr_set)(const struct lu_env *env, - struct cl_object *obj, - struct cl_req_attr *attr); -}; - -/** - * Extended header for client object. - */ -struct cl_object_header { - /** Standard lu_object_header. cl_object::co_lu::lo_header points - * here. - */ - struct lu_object_header coh_lu; - - /** - * Parent object. It is assumed that an object has a well-defined - * parent, but not a well-defined child (there may be multiple - * sub-objects, for the same top-object). cl_object_header::coh_parent - * field allows certain code to be written generically, without - * limiting possible cl_object layouts unduly. - */ - struct cl_object_header *coh_parent; - /** - * Protects consistency between cl_attr of parent object and - * attributes of sub-objects, that the former is calculated ("merged") - * from. - * - * \todo XXX this can be read/write lock if needed. - */ - spinlock_t coh_attr_guard; - /** - * Size of cl_page + page slices - */ - unsigned short coh_page_bufsize; - /** - * Number of objects above this one: 0 for a top-object, 1 for its - * sub-object, etc. - */ - unsigned char coh_nesting; -}; - -/** - * Helper macro: iterate over all layers of the object \a obj, assigning every - * layer top-to-bottom to \a slice. - */ -#define cl_object_for_each(slice, obj) \ - list_for_each_entry((slice), \ - &(obj)->co_lu.lo_header->loh_layers, \ - co_lu.lo_linkage) -/** - * Helper macro: iterate over all layers of the object \a obj, assigning every - * layer bottom-to-top to \a slice. - */ -#define cl_object_for_each_reverse(slice, obj) \ - list_for_each_entry_reverse((slice), \ - &(obj)->co_lu.lo_header->loh_layers, \ - co_lu.lo_linkage) -/** @} cl_object */ - -#define CL_PAGE_EOF ((pgoff_t)~0ull) - -/** \addtogroup cl_page cl_page - * @{ - */ - -/** \struct cl_page - * Layered client page. - * - * cl_page: represents a portion of a file, cached in the memory. All pages - * of the given file are of the same size, and are kept in the radix tree - * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects - * of the top-level file object are first class cl_objects, they have their - * own radix trees of pages and hence page is implemented as a sequence of - * struct cl_pages's, linked into double-linked list through - * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the - * corresponding radix tree at the corresponding logical offset. - * - * cl_page is associated with VM page of the hosting environment (struct - * page in Linux kernel, for example), struct page. It is assumed, that this - * association is implemented by one of cl_page layers (top layer in the - * current design) that - * - * - intercepts per-VM-page call-backs made by the environment (e.g., - * memory pressure), - * - * - translates state (page flag bits) and locking between lustre and - * environment. - * - * The association between cl_page and struct page is immutable and - * established when cl_page is created. - * - * cl_page can be "owned" by a particular cl_io (see below), guaranteeing - * this io an exclusive access to this page w.r.t. other io attempts and - * various events changing page state (such as transfer completion, or - * eviction of the page from the memory). Note, that in general cl_io - * cannot be identified with a particular thread, and page ownership is not - * exactly equal to the current thread holding a lock on the page. Layer - * implementing association between cl_page and struct page has to implement - * ownership on top of available synchronization mechanisms. - * - * While lustre client maintains the notion of an page ownership by io, - * hosting MM/VM usually has its own page concurrency control - * mechanisms. For example, in Linux, page access is synchronized by the - * per-page PG_locked bit-lock, and generic kernel code (generic_file_*()) - * takes care to acquire and release such locks as necessary around the - * calls to the file system methods (->readpage(), ->prepare_write(), - * ->commit_write(), etc.). This leads to the situation when there are two - * different ways to own a page in the client: - * - * - client code explicitly and voluntary owns the page (cl_page_own()); - * - * - VM locks a page and then calls the client, that has "to assume" - * the ownership from the VM (cl_page_assume()). - * - * Dual methods to release ownership are cl_page_disown() and - * cl_page_unassume(). - * - * cl_page is reference counted (cl_page::cp_ref). When reference counter - * drops to 0, the page is returned to the cache, unless it is in - * cl_page_state::CPS_FREEING state, in which case it is immediately - * destroyed. - * - * The general logic guaranteeing the absence of "existential races" for - * pages is the following: - * - * - there are fixed known ways for a thread to obtain a new reference - * to a page: - * - * - by doing a lookup in the cl_object radix tree, protected by the - * spin-lock; - * - * - by starting from VM-locked struct page and following some - * hosting environment method (e.g., following ->private pointer in - * the case of Linux kernel), see cl_vmpage_page(); - * - * - when the page enters cl_page_state::CPS_FREEING state, all these - * ways are severed with the proper synchronization - * (cl_page_delete()); - * - * - entry into cl_page_state::CPS_FREEING is serialized by the VM page - * lock; - * - * - no new references to the page in cl_page_state::CPS_FREEING state - * are allowed (checked in cl_page_get()). - * - * Together this guarantees that when last reference to a - * cl_page_state::CPS_FREEING page is released, it is safe to destroy the - * page, as neither references to it can be acquired at that point, nor - * ones exist. - * - * cl_page is a state machine. States are enumerated in enum - * cl_page_state. Possible state transitions are enumerated in - * cl_page_state_set(). State transition process (i.e., actual changing of - * cl_page::cp_state field) is protected by the lock on the underlying VM - * page. - * - * Linux Kernel implementation. - * - * Binding between cl_page and struct page (which is a typedef for - * struct page) is implemented in the vvp layer. cl_page is attached to the - * ->private pointer of the struct page, together with the setting of - * PG_private bit in page->flags, and acquiring additional reference on the - * struct page (much like struct buffer_head, or any similar file system - * private data structures). - * - * PG_locked lock is used to implement both ownership and transfer - * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}} - * states. No additional references are acquired for the duration of the - * transfer. - * - * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where - * write-out is "protected" by the special PG_writeback bit. - */ - -/** - * States of cl_page. cl_page.c assumes particular order here. - * - * The page state machine is rather crude, as it doesn't recognize finer page - * states like "dirty" or "up to date". This is because such states are not - * always well defined for the whole stack (see, for example, the - * implementation of the read-ahead, that hides page up-to-dateness to track - * cache hits accurately). Such sub-states are maintained by the layers that - * are interested in them. - */ -enum cl_page_state { - /** - * Page is in the cache, un-owned. Page leaves cached state in the - * following cases: - * - * - [cl_page_state::CPS_OWNED] io comes across the page and - * owns it; - * - * - [cl_page_state::CPS_PAGEOUT] page is dirty, the - * req-formation engine decides that it wants to include this page - * into an RPC being constructed, and yanks it from the cache; - * - * - [cl_page_state::CPS_FREEING] VM callback is executed to - * evict the page form the memory; - * - * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL - */ - CPS_CACHED, - /** - * Page is exclusively owned by some cl_io. Page may end up in this - * state as a result of - * - * - io creating new page and immediately owning it; - * - * - [cl_page_state::CPS_CACHED] io finding existing cached page - * and owning it; - * - * - [cl_page_state::CPS_OWNED] io finding existing owned page - * and waiting for owner to release the page; - * - * Page leaves owned state in the following cases: - * - * - [cl_page_state::CPS_CACHED] io decides to leave the page in - * the cache, doing nothing; - * - * - [cl_page_state::CPS_PAGEIN] io starts read transfer for - * this page; - * - * - [cl_page_state::CPS_PAGEOUT] io starts immediate write - * transfer for this page; - * - * - [cl_page_state::CPS_FREEING] io decides to destroy this - * page (e.g., as part of truncate or extent lock cancellation). - * - * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL - */ - CPS_OWNED, - /** - * Page is being written out, as a part of a transfer. This state is - * entered when req-formation logic decided that it wants this page to - * be sent through the wire _now_. Specifically, it means that once - * this state is achieved, transfer completion handler (with either - * success or failure indication) is guaranteed to be executed against - * this page independently of any locks and any scheduling decisions - * made by the hosting environment (that effectively means that the - * page is never put into cl_page_state::CPS_PAGEOUT state "in - * advance". This property is mentioned, because it is important when - * reasoning about possible dead-locks in the system). The page can - * enter this state as a result of - * - * - [cl_page_state::CPS_OWNED] an io requesting an immediate - * write-out of this page, or - * - * - [cl_page_state::CPS_CACHED] req-forming engine deciding - * that it has enough dirty pages cached to issue a "good" - * transfer. - * - * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer - * is completed---it is moved into cl_page_state::CPS_CACHED state. - * - * Underlying VM page is locked for the duration of transfer. - * - * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL - */ - CPS_PAGEOUT, - /** - * Page is being read in, as a part of a transfer. This is quite - * similar to the cl_page_state::CPS_PAGEOUT state, except that - * read-in is always "immediate"---there is no such thing a sudden - * construction of read request from cached, presumably not up to date, - * pages. - * - * Underlying VM page is locked for the duration of transfer. - * - * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL - */ - CPS_PAGEIN, - /** - * Page is being destroyed. This state is entered when client decides - * that page has to be deleted from its host object, as, e.g., a part - * of truncate. - * - * Once this state is reached, there is no way to escape it. - * - * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL - */ - CPS_FREEING, - CPS_NR -}; - -enum cl_page_type { - /** Host page, the page is from the host inode which the cl_page - * belongs to. - */ - CPT_CACHEABLE = 1, - - /** Transient page, the transient cl_page is used to bind a cl_page - * to vmpage which is not belonging to the same object of cl_page. - * it is used in DirectIO and lockless IO. - */ - CPT_TRANSIENT, -}; - -/** - * Fields are protected by the lock on struct page, except for atomics and - * immutables. - * - * \invariant Data type invariants are in cl_page_invariant(). Basically: - * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked - * list, consistent with the parent/child pointers in the cl_page::cp_obj and - * cl_page::cp_owner (when set). - */ -struct cl_page { - /** Reference counter. */ - atomic_t cp_ref; - /** An object this page is a part of. Immutable after creation. */ - struct cl_object *cp_obj; - /** vmpage */ - struct page *cp_vmpage; - /** Linkage of pages within group. Pages must be owned */ - struct list_head cp_batch; - /** List of slices. Immutable after creation. */ - struct list_head cp_layers; - /** - * Page state. This field is const to avoid accidental update, it is - * modified only internally within cl_page.c. Protected by a VM lock. - */ - const enum cl_page_state cp_state; - /** - * Page type. Only CPT_TRANSIENT is used so far. Immutable after - * creation. - */ - enum cl_page_type cp_type; - - /** - * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned - * by sub-io. Protected by a VM lock. - */ - struct cl_io *cp_owner; - /** List of references to this page, for debugging. */ - struct lu_ref cp_reference; - /** Link to an object, for debugging. */ - struct lu_ref_link cp_obj_ref; - /** Link to a queue, for debugging. */ - struct lu_ref_link cp_queue_ref; - /** Assigned if doing a sync_io */ - struct cl_sync_io *cp_sync_io; -}; - -/** - * Per-layer part of cl_page. - * - * \see vvp_page, lov_page, osc_page - */ -struct cl_page_slice { - struct cl_page *cpl_page; - pgoff_t cpl_index; - /** - * Object slice corresponding to this page slice. Immutable after - * creation. - */ - struct cl_object *cpl_obj; - const struct cl_page_operations *cpl_ops; - /** Linkage into cl_page::cp_layers. Immutable after creation. */ - struct list_head cpl_linkage; -}; - -/** - * Lock mode. For the client extent locks. - * - * \ingroup cl_lock - */ -enum cl_lock_mode { - CLM_READ, - CLM_WRITE, - CLM_GROUP -}; - -/** - * Requested transfer type. - */ -enum cl_req_type { - CRT_READ, - CRT_WRITE, - CRT_NR -}; - -/** - * Per-layer page operations. - * - * Methods taking an \a io argument are for the activity happening in the - * context of given \a io. Page is assumed to be owned by that io, except for - * the obvious cases (like cl_page_operations::cpo_own()). - * - * \see vvp_page_ops, lov_page_ops, osc_page_ops - */ -struct cl_page_operations { - /** - * cl_page<->struct page methods. Only one layer in the stack has to - * implement these. Current code assumes that this functionality is - * provided by the topmost layer, see cl_page_disown0() as an example. - */ - - /** - * Called when \a io acquires this page into the exclusive - * ownership. When this method returns, it is guaranteed that the is - * not owned by other io, and no transfer is going on against - * it. Optional. - * - * \see cl_page_own() - * \see vvp_page_own(), lov_page_own() - */ - int (*cpo_own)(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *io, int nonblock); - /** Called when ownership it yielded. Optional. - * - * \see cl_page_disown() - * \see vvp_page_disown() - */ - void (*cpo_disown)(const struct lu_env *env, - const struct cl_page_slice *slice, struct cl_io *io); - /** - * Called for a page that is already "owned" by \a io from VM point of - * view. Optional. - * - * \see cl_page_assume() - * \see vvp_page_assume(), lov_page_assume() - */ - void (*cpo_assume)(const struct lu_env *env, - const struct cl_page_slice *slice, struct cl_io *io); - /** Dual to cl_page_operations::cpo_assume(). Optional. Called - * bottom-to-top when IO releases a page without actually unlocking - * it. - * - * \see cl_page_unassume() - * \see vvp_page_unassume() - */ - void (*cpo_unassume)(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *io); - /** - * Announces whether the page contains valid data or not by \a uptodate. - * - * \see cl_page_export() - * \see vvp_page_export() - */ - void (*cpo_export)(const struct lu_env *env, - const struct cl_page_slice *slice, int uptodate); - /** - * Checks whether underlying VM page is locked (in the suitable - * sense). Used for assertions. - * - * \retval -EBUSY: page is protected by a lock of a given mode; - * \retval -ENODATA: page is not protected by a lock; - * \retval 0: this layer cannot decide. (Should never happen.) - */ - int (*cpo_is_vmlocked)(const struct lu_env *env, - const struct cl_page_slice *slice); - /** - * Page destruction. - */ - - /** - * Called when page is truncated from the object. Optional. - * - * \see cl_page_discard() - * \see vvp_page_discard(), osc_page_discard() - */ - void (*cpo_discard)(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *io); - /** - * Called when page is removed from the cache, and is about to being - * destroyed. Optional. - * - * \see cl_page_delete() - * \see vvp_page_delete(), osc_page_delete() - */ - void (*cpo_delete)(const struct lu_env *env, - const struct cl_page_slice *slice); - /** Destructor. Frees resources and slice itself. */ - void (*cpo_fini)(const struct lu_env *env, - struct cl_page_slice *slice); - /** - * Optional debugging helper. Prints given page slice. - * - * \see cl_page_print() - */ - int (*cpo_print)(const struct lu_env *env, - const struct cl_page_slice *slice, - void *cookie, lu_printer_t p); - /** - * \name transfer - * - * Transfer methods. - * - * @{ - */ - /** - * Request type dependent vector of operations. - * - * Transfer operations depend on transfer mode (cl_req_type). To avoid - * passing transfer mode to each and every of these methods, and to - * avoid branching on request type inside of the methods, separate - * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are - * provided. That is, method invocation usually looks like - * - * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...); - */ - struct { - /** - * Called when a page is submitted for a transfer as a part of - * cl_page_list. - * - * \return 0 : page is eligible for submission; - * \return -EALREADY : skip this page; - * \return -ve : error. - * - * \see cl_page_prep() - */ - int (*cpo_prep)(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *io); - /** - * Completion handler. This is guaranteed to be eventually - * fired after cl_page_operations::cpo_prep() or - * cl_page_operations::cpo_make_ready() call. - * - * This method can be called in a non-blocking context. It is - * guaranteed however, that the page involved and its object - * are pinned in memory (and, hence, calling cl_page_put() is - * safe). - * - * \see cl_page_completion() - */ - void (*cpo_completion)(const struct lu_env *env, - const struct cl_page_slice *slice, - int ioret); - /** - * Called when cached page is about to be added to the - * ptlrpc request as a part of req formation. - * - * \return 0 : proceed with this page; - * \return -EAGAIN : skip this page; - * \return -ve : error. - * - * \see cl_page_make_ready() - */ - int (*cpo_make_ready)(const struct lu_env *env, - const struct cl_page_slice *slice); - } io[CRT_NR]; - /** - * Tell transfer engine that only [to, from] part of a page should be - * transmitted. - * - * This is used for immediate transfers. - * - * \todo XXX this is not very good interface. It would be much better - * if all transfer parameters were supplied as arguments to - * cl_io_operations::cio_submit() call, but it is not clear how to do - * this for page queues. - * - * \see cl_page_clip() - */ - void (*cpo_clip)(const struct lu_env *env, - const struct cl_page_slice *slice, - int from, int to); - /** - * \pre the page was queued for transferring. - * \post page is removed from client's pending list, or -EBUSY - * is returned if it has already been in transferring. - * - * This is one of seldom page operation which is: - * 0. called from top level; - * 1. don't have vmpage locked; - * 2. every layer should synchronize execution of its ->cpo_cancel() - * with completion handlers. Osc uses client obd lock for this - * purpose. Based on there is no vvp_page_cancel and - * lov_page_cancel(), cpo_cancel is defacto protected by client lock. - * - * \see osc_page_cancel(). - */ - int (*cpo_cancel)(const struct lu_env *env, - const struct cl_page_slice *slice); - /** - * Write out a page by kernel. This is only called by ll_writepage - * right now. - * - * \see cl_page_flush() - */ - int (*cpo_flush)(const struct lu_env *env, - const struct cl_page_slice *slice, - struct cl_io *io); - /** @} transfer */ -}; - -/** - * Helper macro, dumping detailed information about \a page into a log. - */ -#define CL_PAGE_DEBUG(mask, env, page, format, ...) \ -do { \ - if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ - LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ - cl_page_print(env, &msgdata, lu_cdebug_printer, page); \ - CDEBUG(mask, format, ## __VA_ARGS__); \ - } \ -} while (0) - -/** - * Helper macro, dumping shorter information about \a page into a log. - */ -#define CL_PAGE_HEADER(mask, env, page, format, ...) \ -do { \ - if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ - LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ - cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \ - CDEBUG(mask, format, ## __VA_ARGS__); \ - } \ -} while (0) - -static inline struct page *cl_page_vmpage(struct cl_page *page) -{ - LASSERT(page->cp_vmpage); - return page->cp_vmpage; -} - -/** - * Check if a cl_page is in use. - * - * Client cache holds a refcount, this refcount will be dropped when - * the page is taken out of cache, see vvp_page_delete(). - */ -static inline bool __page_in_use(const struct cl_page *page, int refc) -{ - return (atomic_read(&page->cp_ref) > refc + 1); -} - -/** - * Caller itself holds a refcount of cl_page. - */ -#define cl_page_in_use(pg) __page_in_use(pg, 1) -/** - * Caller doesn't hold a refcount. - */ -#define cl_page_in_use_noref(pg) __page_in_use(pg, 0) - -/** @} cl_page */ - -/** \addtogroup cl_lock cl_lock - * @{ - */ -/** \struct cl_lock - * - * Extent locking on the client. - * - * LAYERING - * - * The locking model of the new client code is built around - * - * struct cl_lock - * - * data-type representing an extent lock on a regular file. cl_lock is a - * layered object (much like cl_object and cl_page), it consists of a header - * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to - * cl_lock::cll_layers list through cl_lock_slice::cls_linkage. - * - * Typical cl_lock consists of the two layers: - * - * - vvp_lock (vvp specific data), and - * - lov_lock (lov specific data). - * - * lov_lock contains an array of sub-locks. Each of these sub-locks is a - * normal cl_lock: it has a header (struct cl_lock) and a list of layers: - * - * - lovsub_lock, and - * - osc_lock - * - * Each sub-lock is associated with a cl_object (representing stripe - * sub-object or the file to which top-level cl_lock is associated to), and is - * linked into that cl_object::coh_locks. In this respect cl_lock is similar to - * cl_object (that at lov layer also fans out into multiple sub-objects), and - * is different from cl_page, that doesn't fan out (there is usually exactly - * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock - * a "top-lock" and its lovsub-osc portion a "sub-lock". - * - * LIFE CYCLE - * - * cl_lock is a cacheless data container for the requirements of locks to - * complete the IO. cl_lock is created before I/O starts and destroyed when the - * I/O is complete. - * - * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached - * to cl_lock at OSC layer. LDLM lock is still cacheable. - * - * INTERFACE AND USAGE - * - * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A - * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue() - * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock - * consists of multiple sub cl_locks, each sub locks will be enqueued - * correspondingly. At OSC layer, the lock enqueue request will tend to reuse - * cached LDLM lock; otherwise a new LDLM lock will have to be requested from - * OST side. - * - * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel() - * method will be called for each layer to release the resource held by this - * lock. At OSC layer, the reference count of LDLM lock, which is held at - * clo_enqueue time, is released. - * - * LDLM lock can only be canceled if there is no cl_lock using it. - * - * Overall process of the locking during IO operation is as following: - * - * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock() - * is called on each layer. Responsibility of this method is to add locks, - * needed by a given layer into cl_io.ci_lockset. - * - * - once locks for all layers were collected, they are sorted to avoid - * dead-locks (cl_io_locks_sort()), and enqueued. - * - * - when all locks are acquired, IO is performed; - * - * - locks are released after IO is complete. - * - * Striping introduces major additional complexity into locking. The - * fundamental problem is that it is generally unsafe to actively use (hold) - * two locks on the different OST servers at the same time, as this introduces - * inter-server dependency and can lead to cascading evictions. - * - * Basic solution is to sub-divide large read/write IOs into smaller pieces so - * that no multi-stripe locks are taken (note that this design abandons POSIX - * read/write semantics). Such pieces ideally can be executed concurrently. At - * the same time, certain types of IO cannot be sub-divived, without - * sacrificing correctness. This includes: - * - * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee - * atomicity; - * - * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken. - * - * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where - * buf is a part of memory mapped Lustre file, a lock or locks protecting buf - * has to be held together with the usual lock on [offset, offset + count]. - * - * Interaction with DLM - * - * In the expected setup, cl_lock is ultimately backed up by a collection of - * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is - * implemented in osc layer, that also matches DLM events (ASTs, cancellation, - * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed - * description of interaction with DLM. - */ - -/** - * Lock description. - */ -struct cl_lock_descr { - /** Object this lock is granted for. */ - struct cl_object *cld_obj; - /** Index of the first page protected by this lock. */ - pgoff_t cld_start; - /** Index of the last page (inclusive) protected by this lock. */ - pgoff_t cld_end; - /** Group ID, for group lock */ - __u64 cld_gid; - /** Lock mode. */ - enum cl_lock_mode cld_mode; - /** - * flags to enqueue lock. A combination of bit-flags from - * enum cl_enq_flags. - */ - __u32 cld_enq_flags; -}; - -#define DDESCR "%s(%d):[%lu, %lu]:%x" -#define PDESCR(descr) \ - cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \ - (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags - -const char *cl_lock_mode_name(const enum cl_lock_mode mode); - -/** - * Layered client lock. - */ -struct cl_lock { - /** List of slices. Immutable after creation. */ - struct list_head cll_layers; - /** lock attribute, extent, cl_object, etc. */ - struct cl_lock_descr cll_descr; -}; - -/** - * Per-layer part of cl_lock - * - * \see vvp_lock, lov_lock, lovsub_lock, osc_lock - */ -struct cl_lock_slice { - struct cl_lock *cls_lock; - /** Object slice corresponding to this lock slice. Immutable after - * creation. - */ - struct cl_object *cls_obj; - const struct cl_lock_operations *cls_ops; - /** Linkage into cl_lock::cll_layers. Immutable after creation. */ - struct list_head cls_linkage; -}; - -/** - * - * \see vvp_lock_ops, lov_lock_ops, lovsub_lock_ops, osc_lock_ops - */ -struct cl_lock_operations { - /** @{ */ - /** - * Attempts to enqueue the lock. Called top-to-bottom. - * - * \retval 0 this layer has enqueued the lock successfully - * \retval >0 this layer has enqueued the lock, but need to wait on - * @anchor for resources - * \retval -ve failure - * - * \see vvp_lock_enqueue(), lov_lock_enqueue(), lovsub_lock_enqueue(), - * \see osc_lock_enqueue() - */ - int (*clo_enqueue)(const struct lu_env *env, - const struct cl_lock_slice *slice, - struct cl_io *io, struct cl_sync_io *anchor); - /** - * Cancel a lock, release its DLM lock ref, while does not cancel the - * DLM lock - */ - void (*clo_cancel)(const struct lu_env *env, - const struct cl_lock_slice *slice); - /** @} */ - /** - * Destructor. Frees resources and the slice. - * - * \see vvp_lock_fini(), lov_lock_fini(), lovsub_lock_fini(), - * \see osc_lock_fini() - */ - void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice); - /** - * Optional debugging helper. Prints given lock slice. - */ - int (*clo_print)(const struct lu_env *env, - void *cookie, lu_printer_t p, - const struct cl_lock_slice *slice); -}; - -#define CL_LOCK_DEBUG(mask, env, lock, format, ...) \ -do { \ - LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ - \ - if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ - cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \ - CDEBUG(mask, format, ## __VA_ARGS__); \ - } \ -} while (0) - -#define CL_LOCK_ASSERT(expr, env, lock) do { \ - if (likely(expr)) \ - break; \ - \ - CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \ - LBUG(); \ -} while (0) - -/** @} cl_lock */ - -/** \addtogroup cl_page_list cl_page_list - * Page list used to perform collective operations on a group of pages. - * - * Pages are added to the list one by one. cl_page_list acquires a reference - * for every page in it. Page list is used to perform collective operations on - * pages: - * - * - submit pages for an immediate transfer, - * - * - own pages on behalf of certain io (waiting for each page in turn), - * - * - discard pages. - * - * When list is finalized, it releases references on all pages it still has. - * - * \todo XXX concurrency control. - * - * @{ - */ -struct cl_page_list { - unsigned int pl_nr; - struct list_head pl_pages; - struct task_struct *pl_owner; -}; - -/** - * A 2-queue of pages. A convenience data-type for common use case, 2-queue - * contains an incoming page list and an outgoing page list. - */ -struct cl_2queue { - struct cl_page_list c2_qin; - struct cl_page_list c2_qout; -}; - -/** @} cl_page_list */ - -/** \addtogroup cl_io cl_io - * @{ - */ -/** \struct cl_io - * I/O - * - * cl_io represents a high level I/O activity like - * read(2)/write(2)/truncate(2) system call, or cancellation of an extent - * lock. - * - * cl_io is a layered object, much like cl_{object,page,lock} but with one - * important distinction. We want to minimize number of calls to the allocator - * in the fast path, e.g., in the case of read(2) when everything is cached: - * client already owns the lock over region being read, and data are cached - * due to read-ahead. To avoid allocation of cl_io layers in such situations, - * per-layer io state is stored in the session, associated with the io, see - * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized - * by using free-lists, see cl_env_get(). - * - * There is a small predefined number of possible io types, enumerated in enum - * cl_io_type. - * - * cl_io is a state machine, that can be advanced concurrently by the multiple - * threads. It is up to these threads to control the concurrency and, - * specifically, to detect when io is done, and its state can be safely - * released. - * - * For read/write io overall execution plan is as following: - * - * (0) initialize io state through all layers; - * - * (1) loop: prepare chunk of work to do - * - * (2) call all layers to collect locks they need to process current chunk - * - * (3) sort all locks to avoid dead-locks, and acquire them - * - * (4) process the chunk: call per-page methods - * cl_io_operations::cio_prepare_write(), - * cl_io_operations::cio_commit_write() for write) - * - * (5) release locks - * - * (6) repeat loop. - * - * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to - * address allocation efficiency issues mentioned above), and returns with the - * special error condition from per-page method when current sub-io has to - * block. This causes io loop to be repeated, and lov switches to the next - * sub-io in its cl_io_operations::cio_iter_init() implementation. - */ - -/** IO types */ -enum cl_io_type { - /** read system call */ - CIT_READ = 1, - /** write system call */ - CIT_WRITE, - /** truncate, utime system calls */ - CIT_SETATTR, - /** get data version */ - CIT_DATA_VERSION, - /** - * page fault handling - */ - CIT_FAULT, - /** - * fsync system call handling - * To write out a range of file - */ - CIT_FSYNC, - /** - * Miscellaneous io. This is used for occasional io activity that - * doesn't fit into other types. Currently this is used for: - * - * - cancellation of an extent lock. This io exists as a context - * to write dirty pages from under the lock being canceled back - * to the server; - * - * - VM induced page write-out. An io context for writing page out - * for memory cleansing; - * - * - glimpse. An io context to acquire glimpse lock. - * - * - grouplock. An io context to acquire group lock. - * - * CIT_MISC io is used simply as a context in which locks and pages - * are manipulated. Such io has no internal "process", that is, - * cl_io_loop() is never called for it. - */ - CIT_MISC, - CIT_OP_NR -}; - -/** - * States of cl_io state machine - */ -enum cl_io_state { - /** Not initialized. */ - CIS_ZERO, - /** Initialized. */ - CIS_INIT, - /** IO iteration started. */ - CIS_IT_STARTED, - /** Locks taken. */ - CIS_LOCKED, - /** Actual IO is in progress. */ - CIS_IO_GOING, - /** IO for the current iteration finished. */ - CIS_IO_FINISHED, - /** Locks released. */ - CIS_UNLOCKED, - /** Iteration completed. */ - CIS_IT_ENDED, - /** cl_io finalized. */ - CIS_FINI -}; - -/** - * IO state private for a layer. - * - * This is usually embedded into layer session data, rather than allocated - * dynamically. - * - * \see vvp_io, lov_io, osc_io - */ -struct cl_io_slice { - struct cl_io *cis_io; - /** corresponding object slice. Immutable after creation. */ - struct cl_object *cis_obj; - /** io operations. Immutable after creation. */ - const struct cl_io_operations *cis_iop; - /** - * linkage into a list of all slices for a given cl_io, hanging off - * cl_io::ci_layers. Immutable after creation. - */ - struct list_head cis_linkage; -}; - -typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *, - struct cl_page *); - -struct cl_read_ahead { - /* - * Maximum page index the readahead window will end. - * This is determined DLM lock coverage, RPC and stripe boundary. - * cra_end is included. - */ - pgoff_t cra_end; - /* optimal RPC size for this read, by pages */ - unsigned long cra_rpc_size; - /* - * Release callback. If readahead holds resources underneath, this - * function should be called to release it. - */ - void (*cra_release)(const struct lu_env *env, void *cbdata); - /* Callback data for cra_release routine */ - void *cra_cbdata; -}; - -static inline void cl_read_ahead_release(const struct lu_env *env, - struct cl_read_ahead *ra) -{ - if (ra->cra_release) - ra->cra_release(env, ra->cra_cbdata); - memset(ra, 0, sizeof(*ra)); -} - -/** - * Per-layer io operations. - * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops - */ -struct cl_io_operations { - /** - * Vector of io state transition methods for every io type. - * - * \see cl_page_operations::io - */ - struct { - /** - * Prepare io iteration at a given layer. - * - * Called top-to-bottom at the beginning of each iteration of - * "io loop" (if it makes sense for this type of io). Here - * layer selects what work it will do during this iteration. - * - * \see cl_io_operations::cio_iter_fini() - */ - int (*cio_iter_init)(const struct lu_env *env, - const struct cl_io_slice *slice); - /** - * Finalize io iteration. - * - * Called bottom-to-top at the end of each iteration of "io - * loop". Here layers can decide whether IO has to be - * continued. - * - * \see cl_io_operations::cio_iter_init() - */ - void (*cio_iter_fini)(const struct lu_env *env, - const struct cl_io_slice *slice); - /** - * Collect locks for the current iteration of io. - * - * Called top-to-bottom to collect all locks necessary for - * this iteration. This methods shouldn't actually enqueue - * anything, instead it should post a lock through - * cl_io_lock_add(). Once all locks are collected, they are - * sorted and enqueued in the proper order. - */ - int (*cio_lock)(const struct lu_env *env, - const struct cl_io_slice *slice); - /** - * Finalize unlocking. - * - * Called bottom-to-top to finish layer specific unlocking - * functionality, after generic code released all locks - * acquired by cl_io_operations::cio_lock(). - */ - void (*cio_unlock)(const struct lu_env *env, - const struct cl_io_slice *slice); - /** - * Start io iteration. - * - * Once all locks are acquired, called top-to-bottom to - * commence actual IO. In the current implementation, - * top-level vvp_io_{read,write}_start() does all the work - * synchronously by calling generic_file_*(), so other layers - * are called when everything is done. - */ - int (*cio_start)(const struct lu_env *env, - const struct cl_io_slice *slice); - /** - * Called top-to-bottom at the end of io loop. Here layer - * might wait for an unfinished asynchronous io. - */ - void (*cio_end)(const struct lu_env *env, - const struct cl_io_slice *slice); - /** - * Called bottom-to-top to notify layers that read/write IO - * iteration finished, with \a nob bytes transferred. - */ - void (*cio_advance)(const struct lu_env *env, - const struct cl_io_slice *slice, - size_t nob); - /** - * Called once per io, bottom-to-top to release io resources. - */ - void (*cio_fini)(const struct lu_env *env, - const struct cl_io_slice *slice); - } op[CIT_OP_NR]; - - /** - * Submit pages from \a queue->c2_qin for IO, and move - * successfully submitted pages into \a queue->c2_qout. Return - * non-zero if failed to submit even the single page. If - * submission failed after some pages were moved into \a - * queue->c2_qout, completion callback with non-zero ioret is - * executed on them. - */ - int (*cio_submit)(const struct lu_env *env, - const struct cl_io_slice *slice, - enum cl_req_type crt, - struct cl_2queue *queue); - /** - * Queue async page for write. - * The difference between cio_submit and cio_queue is that - * cio_submit is for urgent request. - */ - int (*cio_commit_async)(const struct lu_env *env, - const struct cl_io_slice *slice, - struct cl_page_list *queue, int from, int to, - cl_commit_cbt cb); - /** - * Decide maximum read ahead extent - * - * \pre io->ci_type == CIT_READ - */ - int (*cio_read_ahead)(const struct lu_env *env, - const struct cl_io_slice *slice, - pgoff_t start, struct cl_read_ahead *ra); - /** - * Optional debugging helper. Print given io slice. - */ - int (*cio_print)(const struct lu_env *env, void *cookie, - lu_printer_t p, const struct cl_io_slice *slice); -}; - -/** - * Flags to lock enqueue procedure. - * \ingroup cl_lock - */ -enum cl_enq_flags { - /** - * instruct server to not block, if conflicting lock is found. Instead - * -EWOULDBLOCK is returned immediately. - */ - CEF_NONBLOCK = 0x00000001, - /** - * take lock asynchronously (out of order), as it cannot - * deadlock. This is for LDLM_FL_HAS_INTENT locks used for glimpsing. - */ - CEF_ASYNC = 0x00000002, - /** - * tell the server to instruct (though a flag in the blocking ast) an - * owner of the conflicting lock, that it can drop dirty pages - * protected by this lock, without sending them to the server. - */ - CEF_DISCARD_DATA = 0x00000004, - /** - * tell the sub layers that it must be a `real' lock. This is used for - * mmapped-buffer locks and glimpse locks that must be never converted - * into lockless mode. - * - * \see vvp_mmap_locks(), cl_glimpse_lock(). - */ - CEF_MUST = 0x00000008, - /** - * tell the sub layers that never request a `real' lock. This flag is - * not used currently. - * - * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless - * conversion policy: ci_lockreq describes generic information of lock - * requirement for this IO, especially for locks which belong to the - * object doing IO; however, lock itself may have precise requirements - * that are described by the enqueue flags. - */ - CEF_NEVER = 0x00000010, - /** - * for async glimpse lock. - */ - CEF_AGL = 0x00000020, - /** - * enqueue a lock to test DLM lock existence. - */ - CEF_PEEK = 0x00000040, - /** - * Lock match only. Used by group lock in I/O as group lock - * is known to exist. - */ - CEF_LOCK_MATCH = BIT(7), - /** - * mask of enq_flags. - */ - CEF_MASK = 0x000000ff, -}; - -/** - * Link between lock and io. Intermediate structure is needed, because the - * same lock can be part of multiple io's simultaneously. - */ -struct cl_io_lock_link { - /** linkage into one of cl_lockset lists. */ - struct list_head cill_linkage; - struct cl_lock cill_lock; - /** optional destructor */ - void (*cill_fini)(const struct lu_env *env, - struct cl_io_lock_link *link); -}; -#define cill_descr cill_lock.cll_descr - -/** - * Lock-set represents a collection of locks, that io needs at a - * time. Generally speaking, client tries to avoid holding multiple locks when - * possible, because - * - * - holding extent locks over multiple ost's introduces the danger of - * "cascading timeouts"; - * - * - holding multiple locks over the same ost is still dead-lock prone, - * see comment in osc_lock_enqueue(), - * - * but there are certain situations where this is unavoidable: - * - * - O_APPEND writes have to take [0, EOF] lock for correctness; - * - * - truncate has to take [new-size, EOF] lock for correctness; - * - * - SNS has to take locks across full stripe for correctness; - * - * - in the case when user level buffer, supplied to {read,write}(file0), - * is a part of a memory mapped lustre file, client has to take a dlm - * locks on file0, and all files that back up the buffer (or a part of - * the buffer, that is being processed in the current chunk, in any - * case, there are situations where at least 2 locks are necessary). - * - * In such cases we at least try to take locks in the same consistent - * order. To this end, all locks are first collected, then sorted, and then - * enqueued. - */ -struct cl_lockset { - /** locks to be acquired. */ - struct list_head cls_todo; - /** locks acquired. */ - struct list_head cls_done; -}; - -/** - * Lock requirements(demand) for IO. It should be cl_io_lock_req, - * but 'req' is always to be thought as 'request' :-) - */ -enum cl_io_lock_dmd { - /** Always lock data (e.g., O_APPEND). */ - CILR_MANDATORY = 0, - /** Layers are free to decide between local and global locking. */ - CILR_MAYBE, - /** Never lock: there is no cache (e.g., lockless IO). */ - CILR_NEVER -}; - -enum cl_fsync_mode { - /** start writeback, do not wait for them to finish */ - CL_FSYNC_NONE = 0, - /** start writeback and wait for them to finish */ - CL_FSYNC_LOCAL = 1, - /** discard all of dirty pages in a specific file range */ - CL_FSYNC_DISCARD = 2, - /** start writeback and make sure they have reached storage before - * return. OST_SYNC RPC must be issued and finished - */ - CL_FSYNC_ALL = 3 -}; - -struct cl_io_rw_common { - loff_t crw_pos; - size_t crw_count; - int crw_nonblock; -}; - -/** - * State for io. - * - * cl_io is shared by all threads participating in this IO (in current - * implementation only one thread advances IO, but parallel IO design and - * concurrent copy_*_user() require multiple threads acting on the same IO. It - * is up to these threads to serialize their activities, including updates to - * mutable cl_io fields. - */ -struct cl_io { - /** type of this IO. Immutable after creation. */ - enum cl_io_type ci_type; - /** current state of cl_io state machine. */ - enum cl_io_state ci_state; - /** main object this io is against. Immutable after creation. */ - struct cl_object *ci_obj; - /** - * Upper layer io, of which this io is a part of. Immutable after - * creation. - */ - struct cl_io *ci_parent; - /** List of slices. Immutable after creation. */ - struct list_head ci_layers; - /** list of locks (to be) acquired by this io. */ - struct cl_lockset ci_lockset; - /** lock requirements, this is just a help info for sublayers. */ - enum cl_io_lock_dmd ci_lockreq; - union { - struct cl_rd_io { - struct cl_io_rw_common rd; - } ci_rd; - struct cl_wr_io { - struct cl_io_rw_common wr; - int wr_append; - int wr_sync; - } ci_wr; - struct cl_io_rw_common ci_rw; - struct cl_setattr_io { - struct ost_lvb sa_attr; - unsigned int sa_attr_flags; - unsigned int sa_valid; - int sa_stripe_index; - const struct lu_fid *sa_parent_fid; - } ci_setattr; - struct cl_data_version_io { - u64 dv_data_version; - int dv_flags; - } ci_data_version; - struct cl_fault_io { - /** page index within file. */ - pgoff_t ft_index; - /** bytes valid byte on a faulted page. */ - size_t ft_nob; - /** writable page? for nopage() only */ - int ft_writable; - /** page of an executable? */ - int ft_executable; - /** page_mkwrite() */ - int ft_mkwrite; - /** resulting page */ - struct cl_page *ft_page; - } ci_fault; - struct cl_fsync_io { - loff_t fi_start; - loff_t fi_end; - /** file system level fid */ - struct lu_fid *fi_fid; - enum cl_fsync_mode fi_mode; - /* how many pages were written/discarded */ - unsigned int fi_nr_written; - } ci_fsync; - } u; - struct cl_2queue ci_queue; - size_t ci_nob; - int ci_result; - unsigned int ci_continue:1, - /** - * This io has held grouplock, to inform sublayers that - * don't do lockless i/o. - */ - ci_no_srvlock:1, - /** - * The whole IO need to be restarted because layout has been changed - */ - ci_need_restart:1, - /** - * to not refresh layout - the IO issuer knows that the layout won't - * change(page operations, layout change causes all page to be - * discarded), or it doesn't matter if it changes(sync). - */ - ci_ignore_layout:1, - /** - * Check if layout changed after the IO finishes. Mainly for HSM - * requirement. If IO occurs to openning files, it doesn't need to - * verify layout because HSM won't release openning files. - * Right now, only two operations need to verify layout: glimpse - * and setattr. - */ - ci_verify_layout:1, - /** - * file is released, restore has to be triggered by vvp layer - */ - ci_restore_needed:1, - /** - * O_NOATIME - */ - ci_noatime:1; - /** - * Number of pages owned by this IO. For invariant checking. - */ - unsigned int ci_owned_nr; -}; - -/** @} cl_io */ - -/** - * Per-transfer attributes. - */ -struct cl_req_attr { - enum cl_req_type cra_type; - u64 cra_flags; - struct cl_page *cra_page; - - /** Generic attributes for the server consumption. */ - struct obdo *cra_oa; - /** Jobid */ - char cra_jobid[LUSTRE_JOBID_SIZE]; -}; - -enum cache_stats_item { - /** how many cache lookups were performed */ - CS_lookup = 0, - /** how many times cache lookup resulted in a hit */ - CS_hit, - /** how many entities are in the cache right now */ - CS_total, - /** how many entities in the cache are actively used (and cannot be - * evicted) right now - */ - CS_busy, - /** how many entities were created at all */ - CS_create, - CS_NR -}; - -#define CS_NAMES { "lookup", "hit", "total", "busy", "create" } - -/** - * Stats for a generic cache (similar to inode, lu_object, etc. caches). - */ -struct cache_stats { - const char *cs_name; - atomic_t cs_stats[CS_NR]; -}; - -/** These are not exported so far */ -void cache_stats_init(struct cache_stats *cs, const char *name); - -/** - * Client-side site. This represents particular client stack. "Global" - * variables should (directly or indirectly) be added here to allow multiple - * clients to co-exist in the single address space. - */ -struct cl_site { - struct lu_site cs_lu; - /** - * Statistical counters. Atomics do not scale, something better like - * per-cpu counters is needed. - * - * These are exported as /sys/kernel/debug/lustre/llite/.../site - * - * When interpreting keep in mind that both sub-locks (and sub-pages) - * and top-locks (and top-pages) are accounted here. - */ - struct cache_stats cs_pages; - atomic_t cs_pages_state[CPS_NR]; -}; - -int cl_site_init(struct cl_site *s, struct cl_device *top); -void cl_site_fini(struct cl_site *s); -void cl_stack_fini(const struct lu_env *env, struct cl_device *cl); - -/** - * Output client site statistical counters into a buffer. Suitable for - * ll_rd_*()-style functions. - */ -int cl_site_stats_print(const struct cl_site *site, struct seq_file *m); - -/** - * \name helpers - * - * Type conversion and accessory functions. - */ -/** @{ */ - -static inline struct cl_site *lu2cl_site(const struct lu_site *site) -{ - return container_of(site, struct cl_site, cs_lu); -} - -static inline int lu_device_is_cl(const struct lu_device *d) -{ - return d->ld_type->ldt_tags & LU_DEVICE_CL; -} - -static inline struct cl_device *lu2cl_dev(const struct lu_device *d) -{ - LASSERT(!d || IS_ERR(d) || lu_device_is_cl(d)); - return container_of0(d, struct cl_device, cd_lu_dev); -} - -static inline struct lu_device *cl2lu_dev(struct cl_device *d) -{ - return &d->cd_lu_dev; -} - -static inline struct cl_object *lu2cl(const struct lu_object *o) -{ - LASSERT(!o || IS_ERR(o) || lu_device_is_cl(o->lo_dev)); - return container_of0(o, struct cl_object, co_lu); -} - -static inline const struct cl_object_conf * -lu2cl_conf(const struct lu_object_conf *conf) -{ - return container_of0(conf, struct cl_object_conf, coc_lu); -} - -static inline struct cl_object *cl_object_next(const struct cl_object *obj) -{ - return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL; -} - -static inline struct cl_device *cl_object_device(const struct cl_object *o) -{ - LASSERT(!o || IS_ERR(o) || lu_device_is_cl(o->co_lu.lo_dev)); - return container_of0(o->co_lu.lo_dev, struct cl_device, cd_lu_dev); -} - -static inline struct cl_object_header *luh2coh(const struct lu_object_header *h) -{ - return container_of0(h, struct cl_object_header, coh_lu); -} - -static inline struct cl_site *cl_object_site(const struct cl_object *obj) -{ - return lu2cl_site(obj->co_lu.lo_dev->ld_site); -} - -static inline -struct cl_object_header *cl_object_header(const struct cl_object *obj) -{ - return luh2coh(obj->co_lu.lo_header); -} - -static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t) -{ - return lu_device_init(&d->cd_lu_dev, t); -} - -static inline void cl_device_fini(struct cl_device *d) -{ - lu_device_fini(&d->cd_lu_dev); -} - -void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice, - struct cl_object *obj, pgoff_t index, - const struct cl_page_operations *ops); -void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice, - struct cl_object *obj, - const struct cl_lock_operations *ops); -void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice, - struct cl_object *obj, const struct cl_io_operations *ops); -/** @} helpers */ - -/** \defgroup cl_object cl_object - * @{ - */ -struct cl_object *cl_object_top(struct cl_object *o); -struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd, - const struct lu_fid *fid, - const struct cl_object_conf *c); - -int cl_object_header_init(struct cl_object_header *h); -void cl_object_put(const struct lu_env *env, struct cl_object *o); -void cl_object_get(struct cl_object *o); -void cl_object_attr_lock(struct cl_object *o); -void cl_object_attr_unlock(struct cl_object *o); -int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj, - struct cl_attr *attr); -int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj, - const struct cl_attr *attr, unsigned int valid); -int cl_object_glimpse(const struct lu_env *env, struct cl_object *obj, - struct ost_lvb *lvb); -int cl_conf_set(const struct lu_env *env, struct cl_object *obj, - const struct cl_object_conf *conf); -int cl_object_prune(const struct lu_env *env, struct cl_object *obj); -void cl_object_kill(const struct lu_env *env, struct cl_object *obj); -int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj, - struct lov_user_md __user *lum); -int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj, - struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap, - size_t *buflen); -int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj, - struct cl_layout *cl); -loff_t cl_object_maxbytes(struct cl_object *obj); - -/** - * Returns true, iff \a o0 and \a o1 are slices of the same object. - */ -static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1) -{ - return cl_object_header(o0) == cl_object_header(o1); -} - -static inline void cl_object_page_init(struct cl_object *clob, int size) -{ - clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize; - cl_object_header(clob)->coh_page_bufsize += cfs_size_round(size); - WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512); -} - -static inline void *cl_object_page_slice(struct cl_object *clob, - struct cl_page *page) -{ - return (void *)((char *)page + clob->co_slice_off); -} - -/** - * Return refcount of cl_object. - */ -static inline int cl_object_refc(struct cl_object *clob) -{ - struct lu_object_header *header = clob->co_lu.lo_header; - - return atomic_read(&header->loh_ref); -} - -/** @} cl_object */ - -/** \defgroup cl_page cl_page - * @{ - */ -enum { - CLP_GANG_OKAY = 0, - CLP_GANG_RESCHED, - CLP_GANG_AGAIN, - CLP_GANG_ABORT -}; - -/* callback of cl_page_gang_lookup() */ -struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *obj, - pgoff_t idx, struct page *vmpage, - enum cl_page_type type); -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); -void cl_page_get(struct cl_page *page); -void cl_page_put(const struct lu_env *env, struct cl_page *page); -void cl_page_print(const struct lu_env *env, void *cookie, lu_printer_t printer, - const struct cl_page *pg); -void cl_page_header_print(const struct lu_env *env, void *cookie, - lu_printer_t printer, const struct cl_page *pg); -struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj); - -const struct cl_page_slice *cl_page_at(const struct cl_page *page, - const struct lu_device_type *dtype); - -/** - * \name ownership - * - * Functions dealing with the ownership of page by io. - */ -/** @{ */ - -int cl_page_own(const struct lu_env *env, - struct cl_io *io, struct cl_page *page); -int cl_page_own_try(const struct lu_env *env, - struct cl_io *io, struct cl_page *page); -void cl_page_assume(const struct lu_env *env, - struct cl_io *io, struct cl_page *page); -void cl_page_unassume(const struct lu_env *env, - struct cl_io *io, struct cl_page *pg); -void cl_page_disown(const struct lu_env *env, - struct cl_io *io, struct cl_page *page); -void cl_page_disown0(const struct lu_env *env, - struct cl_io *io, struct cl_page *pg); -int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io); - -/** @} ownership */ - -/** - * \name transfer - * - * Functions dealing with the preparation of a page for a transfer, and - * tracking transfer state. - */ -/** @{ */ -int cl_page_prep(const struct lu_env *env, struct cl_io *io, - struct cl_page *pg, enum cl_req_type crt); -void cl_page_completion(const struct lu_env *env, - struct cl_page *pg, enum cl_req_type crt, int ioret); -int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg, - enum cl_req_type crt); -int cl_page_cache_add(const struct lu_env *env, struct cl_io *io, - struct cl_page *pg, enum cl_req_type crt); -void cl_page_clip(const struct lu_env *env, struct cl_page *pg, - int from, int to); -int cl_page_cancel(const struct lu_env *env, struct cl_page *page); -int cl_page_flush(const struct lu_env *env, struct cl_io *io, - struct cl_page *pg); - -/** @} transfer */ - -/** - * \name helper routines - * Functions to discard, delete and export a cl_page. - */ -/** @{ */ -void cl_page_discard(const struct lu_env *env, struct cl_io *io, - struct cl_page *pg); -void cl_page_delete(const struct lu_env *env, struct cl_page *pg); -int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg); -void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate); -loff_t cl_offset(const struct cl_object *obj, pgoff_t idx); -pgoff_t cl_index(const struct cl_object *obj, loff_t offset); -size_t cl_page_size(const struct cl_object *obj); -int cl_pages_prune(const struct lu_env *env, struct cl_object *obj); - -void cl_lock_print(const struct lu_env *env, void *cookie, - lu_printer_t printer, const struct cl_lock *lock); -void cl_lock_descr_print(const struct lu_env *env, void *cookie, - lu_printer_t printer, - const struct cl_lock_descr *descr); -/* @} helper */ - -/** - * Data structure managing a client's cached pages. A count of - * "unstable" pages is maintained, and an LRU of clean pages is - * maintained. "unstable" pages are pages pinned by the ptlrpc - * layer for recovery purposes. - */ -struct cl_client_cache { - /** - * # of client cache refcount - * # of users (OSCs) + 2 (held by llite and lov) - */ - atomic_t ccc_users; - /** - * # of threads are doing shrinking - */ - unsigned int ccc_lru_shrinkers; - /** - * # of LRU entries available - */ - atomic_long_t ccc_lru_left; - /** - * List of entities(OSCs) for this LRU cache - */ - struct list_head ccc_lru; - /** - * Max # of LRU entries - */ - unsigned long ccc_lru_max; - /** - * Lock to protect ccc_lru list - */ - spinlock_t ccc_lru_lock; - /** - * Set if unstable check is enabled - */ - unsigned int ccc_unstable_check:1; - /** - * # of unstable pages for this mount point - */ - atomic_long_t ccc_unstable_nr; - /** - * Waitq for awaiting unstable pages to reach zero. - * Used at umounting time and signaled on BRW commit - */ - wait_queue_head_t ccc_unstable_waitq; - -}; - -/** - * cl_cache functions - */ -struct cl_client_cache *cl_cache_init(unsigned long lru_page_max); -void cl_cache_incref(struct cl_client_cache *cache); -void cl_cache_decref(struct cl_client_cache *cache); - -/** @} cl_page */ - -/** \defgroup cl_lock cl_lock - * @{ - */ - -int cl_lock_request(const struct lu_env *env, struct cl_io *io, - struct cl_lock *lock); -int cl_lock_init(const struct lu_env *env, struct cl_lock *lock, - const struct cl_io *io); -void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock); -const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock, - const struct lu_device_type *dtype); -void cl_lock_release(const struct lu_env *env, struct cl_lock *lock); -int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io, - struct cl_lock *lock, struct cl_sync_io *anchor); -void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock); - -/** @} cl_lock */ - -/** \defgroup cl_io cl_io - * @{ - */ - -int cl_io_init(const struct lu_env *env, struct cl_io *io, - enum cl_io_type iot, struct cl_object *obj); -int cl_io_sub_init(const struct lu_env *env, struct cl_io *io, - enum cl_io_type iot, struct cl_object *obj); -int cl_io_rw_init(const struct lu_env *env, struct cl_io *io, - enum cl_io_type iot, loff_t pos, size_t count); -int cl_io_loop(const struct lu_env *env, struct cl_io *io); - -void cl_io_fini(const struct lu_env *env, struct cl_io *io); -int cl_io_iter_init(const struct lu_env *env, struct cl_io *io); -void cl_io_iter_fini(const struct lu_env *env, struct cl_io *io); -int cl_io_lock(const struct lu_env *env, struct cl_io *io); -void cl_io_unlock(const struct lu_env *env, struct cl_io *io); -int cl_io_start(const struct lu_env *env, struct cl_io *io); -void cl_io_end(const struct lu_env *env, struct cl_io *io); -int cl_io_lock_add(const struct lu_env *env, struct cl_io *io, - struct cl_io_lock_link *link); -int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io, - struct cl_lock_descr *descr); -int cl_io_submit_rw(const struct lu_env *env, struct cl_io *io, - enum cl_req_type iot, struct cl_2queue *queue); -int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io, - enum cl_req_type iot, struct cl_2queue *queue, - long timeout); -int cl_io_commit_async(const struct lu_env *env, struct cl_io *io, - struct cl_page_list *queue, int from, int to, - cl_commit_cbt cb); -int cl_io_read_ahead(const struct lu_env *env, struct cl_io *io, - pgoff_t start, struct cl_read_ahead *ra); -int cl_io_is_going(const struct lu_env *env); - -/** - * True, iff \a io is an O_APPEND write(2). - */ -static inline int cl_io_is_append(const struct cl_io *io) -{ - return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append; -} - -static inline int cl_io_is_sync_write(const struct cl_io *io) -{ - return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync; -} - -static inline int cl_io_is_mkwrite(const struct cl_io *io) -{ - return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite; -} - -/** - * True, iff \a io is a truncate(2). - */ -static inline int cl_io_is_trunc(const struct cl_io *io) -{ - return io->ci_type == CIT_SETATTR && - (io->u.ci_setattr.sa_valid & ATTR_SIZE); -} - -struct cl_io *cl_io_top(struct cl_io *io); - -#define CL_IO_SLICE_CLEAN(foo_io, base) \ -do { \ - typeof(foo_io) __foo_io = (foo_io); \ - \ - BUILD_BUG_ON(offsetof(typeof(*__foo_io), base) != 0); \ - memset(&__foo_io->base + 1, 0, \ - sizeof(*__foo_io) - sizeof(__foo_io->base)); \ -} while (0) - -/** @} cl_io */ - -/** \defgroup cl_page_list cl_page_list - * @{ - */ - -/** - * Last page in the page list. - */ -static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist) -{ - LASSERT(plist->pl_nr > 0); - return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch); -} - -static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist) -{ - LASSERT(plist->pl_nr > 0); - return list_entry(plist->pl_pages.next, struct cl_page, cp_batch); -} - -/** - * Iterate over pages in a page list. - */ -#define cl_page_list_for_each(page, list) \ - list_for_each_entry((page), &(list)->pl_pages, cp_batch) - -/** - * Iterate over pages in a page list, taking possible removals into account. - */ -#define cl_page_list_for_each_safe(page, temp, list) \ - list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch) - -void cl_page_list_init(struct cl_page_list *plist); -void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page); -void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src, - struct cl_page *page); -void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src, - struct cl_page *page); -void cl_page_list_splice(struct cl_page_list *list, struct cl_page_list *head); -void cl_page_list_del(const struct lu_env *env, struct cl_page_list *plist, - struct cl_page *page); -void cl_page_list_disown(const struct lu_env *env, - struct cl_io *io, struct cl_page_list *plist); -void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist); - -void cl_2queue_init(struct cl_2queue *queue); -void cl_2queue_disown(const struct lu_env *env, - struct cl_io *io, struct cl_2queue *queue); -void cl_2queue_discard(const struct lu_env *env, - struct cl_io *io, struct cl_2queue *queue); -void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue); -void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page); - -/** @} cl_page_list */ - -void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj, - struct cl_req_attr *attr); - -/** \defgroup cl_sync_io cl_sync_io - * @{ - */ - -/** - * Anchor for synchronous transfer. This is allocated on a stack by thread - * doing synchronous transfer, and a pointer to this structure is set up in - * every page submitted for transfer. Transfer completion routine updates - * anchor and wakes up waiting thread when transfer is complete. - */ -struct cl_sync_io { - /** number of pages yet to be transferred. */ - atomic_t csi_sync_nr; - /** error code. */ - int csi_sync_rc; - /** barrier of destroy this structure */ - atomic_t csi_barrier; - /** completion to be signaled when transfer is complete. */ - wait_queue_head_t csi_waitq; - /** callback to invoke when this IO is finished */ - void (*csi_end_io)(const struct lu_env *, - struct cl_sync_io *); -}; - -void cl_sync_io_init(struct cl_sync_io *anchor, int nr, - void (*end)(const struct lu_env *, struct cl_sync_io *)); -int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor, - long timeout); -void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor, - int ioret); -void cl_sync_io_end(const struct lu_env *env, struct cl_sync_io *anchor); - -/** @} cl_sync_io */ - -/** \defgroup cl_env cl_env - * - * lu_env handling for a client. - * - * lu_env is an environment within which lustre code executes. Its major part - * is lu_context---a fast memory allocation mechanism that is used to conserve - * precious kernel stack space. Originally lu_env was designed for a server, - * where - * - * - there is a (mostly) fixed number of threads, and - * - * - call chains have no non-lustre portions inserted between lustre code. - * - * On a client both these assumption fails, because every user thread can - * potentially execute lustre code as part of a system call, and lustre calls - * into VFS or MM that call back into lustre. - * - * To deal with that, cl_env wrapper functions implement the following - * optimizations: - * - * - allocation and destruction of environment is amortized by caching no - * longer used environments instead of destroying them; - * - * \see lu_env, lu_context, lu_context_key - * @{ - */ - -struct lu_env *cl_env_get(u16 *refcheck); -struct lu_env *cl_env_alloc(u16 *refcheck, __u32 tags); -void cl_env_put(struct lu_env *env, u16 *refcheck); -unsigned int cl_env_cache_purge(unsigned int nr); -struct lu_env *cl_env_percpu_get(void); -void cl_env_percpu_put(struct lu_env *env); - -/** @} cl_env */ - -/* - * Misc - */ -void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb); - -struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site, - struct lu_device_type *ldt, - struct lu_device *next); -/** @} clio */ - -int cl_global_init(void); -void cl_global_fini(void); - -#endif /* _LINUX_CL_OBJECT_H */ |