| /* |
| * 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, 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). |
| * |
| * - cl_req represents a collection of pages for a transfer. cl_req is |
| * constructed by req-forming engine that tries to saturate |
| * transport with large and continuous transfers. |
| * |
| * 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 <linux/atomic.h> |
| #include "linux/lustre_compat25.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_device_operations; |
| |
| struct cl_object; |
| struct cl_object_page_operations; |
| struct cl_object_lock_operations; |
| |
| 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; |
| struct cl_req_slice; |
| |
| /** |
| * Operations for each data device in the client stack. |
| * |
| * \see vvp_cl_ops, lov_cl_ops, lovsub_cl_ops, osc_cl_ops |
| */ |
| struct cl_device_operations { |
| /** |
| * Initialize cl_req. This method is called top-to-bottom on all |
| * devices in the stack to get them a chance to allocate layer-private |
| * data, and to attach them to the cl_req by calling |
| * cl_req_slice_add(). |
| * |
| * \see osc_req_init(), lov_req_init(), lovsub_req_init() |
| * \see vvp_req_init() |
| */ |
| int (*cdo_req_init)(const struct lu_env *env, struct cl_device *dev, |
| struct cl_req *req); |
| }; |
| |
| /** |
| * 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; |
| /** Per-layer operation vector. */ |
| const struct cl_device_operations *cd_ops; |
| }; |
| |
| /** \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; |
| }; |
| |
| /** |
| * 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 lustre_md *coc_md; |
| /** |
| * 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 |
| }; |
| |
| /** |
| * 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_set)(const struct lu_env *env, struct cl_object *obj, |
| const struct cl_attr *attr, unsigned 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); |
| }; |
| |
| /** |
| * 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 cl_req 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 cl_req 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, |
| }; |
| |
| /** |
| * Flags maintained for every cl_page. |
| */ |
| enum cl_page_flags { |
| /** |
| * Set when pagein completes. Used for debugging (read completes at |
| * most once for a page). |
| */ |
| CPF_READ_COMPLETED = 1 << 0 |
| }; |
| |
| /** |
| * 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; |
| /** List of slices. Immutable after creation. */ |
| struct list_head cp_layers; |
| /** vmpage */ |
| struct page *cp_vmpage; |
| /** |
| * 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; |
| /** Linkage of pages within group. Protected by cl_page::cp_mutex. */ |
| struct list_head cp_batch; |
| /** Mutex serializing membership of a page in a batch. */ |
| struct mutex cp_mutex; |
| /** Linkage of pages within cl_req. */ |
| struct list_head cp_flight; |
| /** Transfer error. */ |
| int cp_error; |
| |
| /** |
| * 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; |
| /** |
| * Debug information, the task is owning the page. |
| */ |
| struct task_struct *cp_task; |
| /** |
| * Owning IO request in cl_page_state::CPS_PAGEOUT and |
| * cl_page_state::CPS_PAGEIN states. This field is maintained only in |
| * the top-level pages. Protected by a VM lock. |
| */ |
| struct cl_req *cp_req; |
| /** 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; |
| /** Per-page flags from enum cl_page_flags. Protected by a VM lock. */ |
| unsigned cp_flags; |
| /** 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. |
| * \ingroup cl_req |
| */ |
| 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); |
| |
| /** |
| * Checks whether the page is protected by a cl_lock. This is a |
| * per-layer method, because certain layers have ways to check for the |
| * lock much more efficiently than through the generic locks scan, or |
| * implement locking mechanisms separate from cl_lock, e.g., |
| * LL_FILE_GROUP_LOCKED in vvp. If \a pending is true, check for locks |
| * being canceled, or scheduled for cancellation as soon as the last |
| * user goes away, too. |
| * |
| * \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. |
| * |
| * \see cl_page_is_under_lock() |
| */ |
| int (*cpo_is_under_lock)(const struct lu_env *env, |
| const struct cl_page_slice *slice, |
| struct cl_io *io, pgoff_t *max); |
| |
| /** |
| * 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. See comment on cl_req for a description of |
| * transfer formation and life-cycle. |
| * |
| * @{ |
| */ |
| /** |
| * 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 |
| * cl_req 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 int __page_in_use(const struct cl_page *page, int refc) |
| { |
| if (page->cp_type == CPT_CACHEABLE) |
| ++refc; |
| LASSERT(atomic_read(&page->cp_ref) > 0); |
| return (atomic_read(&page->cp_ref) > refc); |
| } |
| |
| #define cl_page_in_use(pg) __page_in_use(pg, 1) |
| #define cl_page_in_use_noref(pg) __page_in_use(pg, 0) |
| |
| static inline struct page *cl_page_vmpage(struct cl_page *page) |
| { |
| LASSERT(page->cp_vmpage); |
| return page->cp_vmpage; |
| } |
| |
| /** @} 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 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_read_page() for read, |
| * 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, |
| /** write system call */ |
| CIT_WRITE, |
| /** truncate, utime system calls */ |
| CIT_SETATTR, |
| /** |
| * 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 *); |
| /** |
| * 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); |
| /** |
| * Read missing page. |
| * |
| * Called by a top-level cl_io_operations::op[CIT_READ]::cio_start() |
| * method, when it hits not-up-to-date page in the range. Optional. |
| * |
| * \pre io->ci_type == CIT_READ |
| */ |
| int (*cio_read_page)(const struct lu_env *env, |
| const struct cl_io_slice *slice, |
| const struct cl_page_slice *page); |
| /** |
| * 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, |
| /** |
| * mask of enq_flags. |
| */ |
| CEF_MASK = 0x0000007f, |
| }; |
| |
| /** |
| * 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_valid; |
| } ci_setattr; |
| struct cl_fault_io { |
| /** page index within file. */ |
| pgoff_t ft_index; |
| /** bytes valid byte on a faulted page. */ |
| int 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 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 ci_owned_nr; |
| }; |
| |
| /** @} cl_io */ |
| |
| /** \addtogroup cl_req cl_req |
| * @{ |
| */ |
| /** \struct cl_req |
| * Transfer. |
| * |
| * There are two possible modes of transfer initiation on the client: |
| * |
| * - immediate transfer: this is started when a high level io wants a page |
| * or a collection of pages to be transferred right away. Examples: |
| * read-ahead, synchronous read in the case of non-page aligned write, |
| * page write-out as a part of extent lock cancellation, page write-out |
| * as a part of memory cleansing. Immediate transfer can be both |
| * cl_req_type::CRT_READ and cl_req_type::CRT_WRITE; |
| * |
| * - opportunistic transfer (cl_req_type::CRT_WRITE only), that happens |
| * when io wants to transfer a page to the server some time later, when |
| * it can be done efficiently. Example: pages dirtied by the write(2) |
| * path. |
| * |
| * In any case, transfer takes place in the form of a cl_req, which is a |
| * representation for a network RPC. |
| * |
| * Pages queued for an opportunistic transfer are cached until it is decided |
| * that efficient RPC can be composed of them. This decision is made by "a |
| * req-formation engine", currently implemented as a part of osc |
| * layer. Req-formation depends on many factors: the size of the resulting |
| * RPC, whether or not multi-object RPCs are supported by the server, |
| * max-rpc-in-flight limitations, size of the dirty cache, etc. |
| * |
| * For the immediate transfer io submits a cl_page_list, that req-formation |
| * engine slices into cl_req's, possibly adding cached pages to some of |
| * the resulting req's. |
| * |
| * Whenever a page from cl_page_list is added to a newly constructed req, its |
| * cl_page_operations::cpo_prep() layer methods are called. At that moment, |
| * page state is atomically changed from cl_page_state::CPS_OWNED to |
| * cl_page_state::CPS_PAGEOUT or cl_page_state::CPS_PAGEIN, cl_page::cp_owner |
| * is zeroed, and cl_page::cp_req is set to the |
| * req. cl_page_operations::cpo_prep() method at the particular layer might |
| * return -EALREADY to indicate that it does not need to submit this page |
| * at all. This is possible, for example, if page, submitted for read, |
| * became up-to-date in the meantime; and for write, the page don't have |
| * dirty bit marked. \see cl_io_submit_rw() |
| * |
| * Whenever a cached page is added to a newly constructed req, its |
| * cl_page_operations::cpo_make_ready() layer methods are called. At that |
| * moment, page state is atomically changed from cl_page_state::CPS_CACHED to |
| * cl_page_state::CPS_PAGEOUT, and cl_page::cp_req is set to |
| * req. cl_page_operations::cpo_make_ready() method at the particular layer |
| * might return -EAGAIN to indicate that this page is not eligible for the |
| * transfer right now. |
| * |
| * FUTURE |
| * |
| * Plan is to divide transfers into "priority bands" (indicated when |
| * submitting cl_page_list, and queuing a page for the opportunistic transfer) |
| * and allow glueing of cached pages to immediate transfers only within single |
| * band. This would make high priority transfers (like lock cancellation or |
| * memory pressure induced write-out) really high priority. |
| * |
| */ |
| |
| /** |
| * Per-transfer attributes. |
| */ |
| struct cl_req_attr { |
| /** Generic attributes for the server consumption. */ |
| struct obdo *cra_oa; |
| /** Jobid */ |
| char cra_jobid[JOBSTATS_JOBID_SIZE]; |
| }; |
| |
| /** |
| * Transfer request operations definable at every layer. |
| * |
| * Concurrency: transfer formation engine synchronizes calls to all transfer |
| * methods. |
| */ |
| struct cl_req_operations { |
| /** |
| * Invoked top-to-bottom by cl_req_prep() when transfer formation is |
| * complete (all pages are added). |
| * |
| * \see osc_req_prep() |
| */ |
| int (*cro_prep)(const struct lu_env *env, |
| const struct cl_req_slice *slice); |
| /** |
| * Called top-to-bottom to fill in \a oa fields. This is called twice |
| * with different flags, see bug 10150 and osc_build_req(). |
| * |
| * \param obj an object from cl_req which attributes are to be set in |
| * \a oa. |
| * |
| * \param oa struct obdo where attributes are placed |
| * |
| * \param flags \a oa fields to be filled. |
| */ |
| void (*cro_attr_set)(const struct lu_env *env, |
| const struct cl_req_slice *slice, |
| const struct cl_object *obj, |
| struct cl_req_attr *attr, u64 flags); |
| /** |
| * Called top-to-bottom from cl_req_completion() to notify layers that |
| * transfer completed. Has to free all state allocated by |
| * cl_device_operations::cdo_req_init(). |
| */ |
| void (*cro_completion)(const struct lu_env *env, |
| const struct cl_req_slice *slice, int ioret); |
| }; |
| |
| /** |
| * A per-object state that (potentially multi-object) transfer request keeps. |
| */ |
| struct cl_req_obj { |
| /** object itself */ |
| struct cl_object *ro_obj; |
| /** reference to cl_req_obj::ro_obj. For debugging. */ |
| struct lu_ref_link ro_obj_ref; |
| /* something else? Number of pages for a given object? */ |
| }; |
| |
| /** |
| * Transfer request. |
| * |
| * Transfer requests are not reference counted, because IO sub-system owns |
| * them exclusively and knows when to free them. |
| * |
| * Life cycle. |
| * |
| * cl_req is created by cl_req_alloc() that calls |
| * cl_device_operations::cdo_req_init() device methods to allocate per-req |
| * state in every layer. |
| * |
| * Then pages are added (cl_req_page_add()), req keeps track of all objects it |
| * contains pages for. |
| * |
| * Once all pages were collected, cl_page_operations::cpo_prep() method is |
| * called top-to-bottom. At that point layers can modify req, let it pass, or |
| * deny it completely. This is to support things like SNS that have transfer |
| * ordering requirements invisible to the individual req-formation engine. |
| * |
| * On transfer completion (or transfer timeout, or failure to initiate the |
| * transfer of an allocated req), cl_req_operations::cro_completion() method |
| * is called, after execution of cl_page_operations::cpo_completion() of all |
| * req's pages. |
| */ |
| struct cl_req { |
| enum cl_req_type crq_type; |
| /** A list of pages being transferred */ |
| struct list_head crq_pages; |
| /** Number of pages in cl_req::crq_pages */ |
| unsigned crq_nrpages; |
| /** An array of objects which pages are in ->crq_pages */ |
| struct cl_req_obj *crq_o; |
| /** Number of elements in cl_req::crq_objs[] */ |
| unsigned crq_nrobjs; |
| struct list_head crq_layers; |
| }; |
| |
| /** |
| * Per-layer state for request. |
| */ |
| struct cl_req_slice { |
| struct cl_req *crs_req; |
| struct cl_device *crs_dev; |
| struct list_head crs_linkage; |
| const struct cl_req_operations *crs_ops; |
| }; |
| |
| /* @} cl_req */ |
| |
| 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); |
| void cl_req_slice_add(struct cl_req *req, struct cl_req_slice *slice, |
| struct cl_device *dev, |
| const struct cl_req_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_set(const struct lu_env *env, struct cl_object *obj, |
| const struct cl_attr *attr, unsigned 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); |
| |
| /** |
| * 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); |
| } |
| |
| 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); |
| 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); |
| int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io, |
| struct cl_page *page, pgoff_t *max_index); |
| loff_t cl_offset(const struct cl_object *obj, pgoff_t idx); |
| pgoff_t cl_index(const struct cl_object *obj, loff_t offset); |
| int 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 users (OSCs) |
| */ |
| atomic_t ccc_users; |
| /** |
| * # of threads are doing shrinking |
| */ |
| unsigned int ccc_lru_shrinkers; |
| /** |
| * # of LRU entries available |
| */ |
| atomic_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; |
| /** |
| * # of unstable pages for this mount point |
| */ |
| atomic_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_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_read_page(const struct lu_env *env, struct cl_io *io, |
| struct cl_page *page); |
| 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_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); \ |
| \ |
| CLASSERT(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 */ |
| |
| /** \defgroup cl_req cl_req |
| * @{ |
| */ |
| struct cl_req *cl_req_alloc(const struct lu_env *env, struct cl_page *page, |
| enum cl_req_type crt, int nr_objects); |
| |
| void cl_req_page_add(const struct lu_env *env, struct cl_req *req, |
| struct cl_page *page); |
| void cl_req_page_done(const struct lu_env *env, struct cl_page *page); |
| int cl_req_prep(const struct lu_env *env, struct cl_req *req); |
| void cl_req_attr_set(const struct lu_env *env, struct cl_req *req, |
| struct cl_req_attr *attr, u64 flags); |
| void cl_req_completion(const struct lu_env *env, struct cl_req *req, int ioret); |
| |
| /** \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 */ |
| |
| /** @} cl_req */ |
| |
| /** \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; |
| * |
| * - there is a notion of "current" environment, attached to the kernel |
| * data structure representing current thread Top-level lustre code |
| * allocates an environment and makes it current, then calls into |
| * non-lustre code, that in turn calls lustre back. Low-level lustre |
| * code thus called can fetch environment created by the top-level code |
| * and reuse it, avoiding additional environment allocation. |
| * Right now, three interfaces can attach the cl_env to running thread: |
| * - cl_env_get |
| * - cl_env_implant |
| * - cl_env_reexit(cl_env_reenter had to be called priorly) |
| * |
| * \see lu_env, lu_context, lu_context_key |
| * @{ |
| */ |
| |
| struct cl_env_nest { |
| int cen_refcheck; |
| void *cen_cookie; |
| }; |
| |
| struct lu_env *cl_env_get(int *refcheck); |
| struct lu_env *cl_env_alloc(int *refcheck, __u32 tags); |
| struct lu_env *cl_env_nested_get(struct cl_env_nest *nest); |
| void cl_env_put(struct lu_env *env, int *refcheck); |
| void cl_env_nested_put(struct cl_env_nest *nest, struct lu_env *env); |
| void *cl_env_reenter(void); |
| void cl_env_reexit(void *cookie); |
| void cl_env_implant(struct lu_env *env, int *refcheck); |
| void cl_env_unplant(struct lu_env *env, int *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 */ |