/* * 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, 2016, 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 #include #include #include #include #include #include #include struct obd_info; 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; /* Project identifier for quota purpose. */ __u32 cat_projid; }; /** * 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, CAT_PROJID = 1 << 9 }; /** * 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; /** whether layout is a composite one */ bool cl_is_composite; }; /** * 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 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, lockless IO and liblustre. */ 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, CLM_MAX, }; /** * 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(const struct cl_page *page) { LASSERT(page->cp_vmpage != NULL); 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 { \ if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ 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_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, /** * ladvise handling * To give advice about access of a file */ CIT_LADVISE, 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 != NULL) 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 = 0x00000080, /** * 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., liblustre). */ 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; struct ost_layout sa_layout; 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; struct cl_ladvise_io { __u64 li_start; __u64 li_end; /** file system level fid */ struct lu_fid *li_fid; enum lu_ladvise_type li_advice; __u64 li_flags; } ci_ladvise; } 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, /** * Need MDS intervention to complete a write. This usually means the * corresponding component is not initialized for the writing extent. */ ci_need_write_intent: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 opertaions 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 */ /** * 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 /proc/fs/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 struct cl_device *lu2cl_dev(const struct lu_device *d) { LASSERT(d == NULL || 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 == NULL || 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_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_header_fini(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 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); struct cl_page *cl_page_top (struct cl_page *page); 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); 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); 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); void cl_io_rw_advance (const struct lu_env *env, struct cl_io *io, size_t nob); int cl_io_cancel (const struct lu_env *env, struct cl_io *io, struct cl_page_list *queue); /** * 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); void cl_io_print(const struct lu_env *env, void *cookie, lu_printer_t printer, const 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_assume (const struct lu_env *env, struct cl_io *io, struct cl_page_list *plist); void cl_page_list_discard(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_add (struct cl_2queue *queue, struct cl_page *page); void cl_2queue_disown (const struct lu_env *env, struct cl_io *io, struct cl_2queue *queue); void cl_2queue_assume (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 assumtpion 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 cl_env_cache_purge(unsigned nr); struct lu_env *cl_env_percpu_get(void); void cl_env_percpu_put(struct lu_env *env); /** @} cl_env */ /* * Misc */ void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr); 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 */