4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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14 * in the LICENSE file that accompanied this code).
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18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
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26 * Copyright (c) 2011, 2015, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
30 * Lustre is a trademark of Sun Microsystems, Inc.
32 #ifndef _LUSTRE_CL_OBJECT_H
33 #define _LUSTRE_CL_OBJECT_H
35 /** \defgroup clio clio
37 * Client objects implement io operations and cache pages.
39 * Examples: lov and osc are implementations of cl interface.
41 * Big Theory Statement.
45 * Client implementation is based on the following data-types:
51 * - cl_lock represents an extent lock on an object.
53 * - cl_io represents high-level i/o activity such as whole read/write
54 * system call, or write-out of pages from under the lock being
55 * canceled. cl_io has sub-ios that can be stopped and resumed
56 * independently, thus achieving high degree of transfer
57 * parallelism. Single cl_io can be advanced forward by
58 * the multiple threads (although in the most usual case of
59 * read/write system call it is associated with the single user
60 * thread, that issued the system call).
64 * - to avoid confusion high-level I/O operation like read or write system
65 * call is referred to as "an io", whereas low-level I/O operation, like
66 * RPC, is referred to as "a transfer"
68 * - "generic code" means generic (not file system specific) code in the
69 * hosting environment. "cl-code" means code (mostly in cl_*.c files) that
70 * is not layer specific.
76 * - cl_object_header::coh_page_guard
79 * See the top comment in cl_object.c for the description of overall locking and
80 * reference-counting design.
82 * See comments below for the description of i/o, page, and dlm-locking
89 * super-class definitions.
91 #include <lu_object.h>
92 #include <lustre_compat.h>
93 #include <linux/atomic.h>
94 #include <linux/mutex.h>
95 #include <linux/radix-tree.h>
96 #include <linux/spinlock.h>
97 #include <linux/wait.h>
106 struct cl_page_slice;
108 struct cl_lock_slice;
110 struct cl_lock_operations;
111 struct cl_page_operations;
119 * Device in the client stack.
121 * \see vvp_device, lov_device, lovsub_device, osc_device
125 struct lu_device cd_lu_dev;
128 /** \addtogroup cl_object cl_object
132 * "Data attributes" of cl_object. Data attributes can be updated
133 * independently for a sub-object, and top-object's attributes are calculated
134 * from sub-objects' ones.
137 /** Object size, in bytes */
140 * Known minimal size, in bytes.
142 * This is only valid when at least one DLM lock is held.
145 /** Modification time. Measured in seconds since epoch. */
147 /** Access time. Measured in seconds since epoch. */
149 /** Change time. Measured in seconds since epoch. */
152 * Blocks allocated to this cl_object on the server file system.
154 * \todo XXX An interface for block size is needed.
158 * User identifier for quota purposes.
162 * Group identifier for quota purposes.
166 /* nlink of the directory */
171 * Fields in cl_attr that are being set.
185 * Sub-class of lu_object with methods common for objects on the client
188 * cl_object: represents a regular file system object, both a file and a
189 * stripe. cl_object is based on lu_object: it is identified by a fid,
190 * layered, cached, hashed, and lrued. Important distinction with the server
191 * side, where md_object and dt_object are used, is that cl_object "fans out"
192 * at the lov/sns level: depending on the file layout, single file is
193 * represented as a set of "sub-objects" (stripes). At the implementation
194 * level, struct lov_object contains an array of cl_objects. Each sub-object
195 * is a full-fledged cl_object, having its fid, living in the lru and hash
198 * This leads to the next important difference with the server side: on the
199 * client, it's quite usual to have objects with the different sequence of
200 * layers. For example, typical top-object is composed of the following
206 * whereas its sub-objects are composed of
211 * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep
212 * track of the object-subobject relationship.
214 * Sub-objects are not cached independently: when top-object is about to
215 * be discarded from the memory, all its sub-objects are torn-down and
218 * \see vvp_object, lov_object, lovsub_object, osc_object
222 struct lu_object co_lu;
223 /** per-object-layer operations */
224 const struct cl_object_operations *co_ops;
225 /** offset of page slice in cl_page buffer */
230 * Description of the client object configuration. This is used for the
231 * creation of a new client object that is identified by a more state than
234 struct cl_object_conf {
236 struct lu_object_conf coc_lu;
239 * Object layout. This is consumed by lov.
241 struct lu_buf coc_layout;
243 * Description of particular stripe location in the
244 * cluster. This is consumed by osc.
246 struct lov_oinfo *coc_oinfo;
249 * VFS inode. This is consumed by vvp.
251 struct inode *coc_inode;
253 * Layout lock handle.
255 struct ldlm_lock *coc_lock;
257 * Operation to handle layout, OBJECT_CONF_XYZ.
263 /** configure layout, set up a new stripe, must be called while
264 * holding layout lock.
267 /** invalidate the current stripe configuration due to losing
270 OBJECT_CONF_INVALIDATE = 1,
271 /** wait for old layout to go away so that new layout can be set up. */
276 CL_LAYOUT_GEN_NONE = (u32)-2, /* layout lock was cancelled */
277 CL_LAYOUT_GEN_EMPTY = (u32)-1, /* for empty layout */
281 /** the buffer to return the layout in lov_mds_md format. */
282 struct lu_buf cl_buf;
283 /** size of layout in lov_mds_md format. */
285 /** Layout generation. */
290 * Operations implemented for each cl object layer.
292 * \see vvp_ops, lov_ops, lovsub_ops, osc_ops
294 struct cl_object_operations {
296 * Initialize page slice for this layer. Called top-to-bottom through
297 * every object layer when a new cl_page is instantiated. Layer
298 * keeping private per-page data, or requiring its own page operations
299 * vector should allocate these data here, and attach then to the page
300 * by calling cl_page_slice_add(). \a vmpage is locked (in the VM
303 * \retval NULL success.
305 * \retval ERR_PTR(errno) failure code.
307 * \retval valid-pointer pointer to already existing referenced page
308 * to be used instead of newly created.
310 int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj,
311 struct cl_page *page, pgoff_t index);
313 * Initialize lock slice for this layer. Called top-to-bottom through
314 * every object layer when a new cl_lock is instantiated. Layer
315 * keeping private per-lock data, or requiring its own lock operations
316 * vector should allocate these data here, and attach then to the lock
317 * by calling cl_lock_slice_add(). Mandatory.
319 int (*coo_lock_init)(const struct lu_env *env,
320 struct cl_object *obj, struct cl_lock *lock,
321 const struct cl_io *io);
323 * Initialize io state for a given layer.
325 * called top-to-bottom once per io existence to initialize io
326 * state. If layer wants to keep some state for this type of io, it
327 * has to embed struct cl_io_slice in lu_env::le_ses, and register
328 * slice with cl_io_slice_add(). It is guaranteed that all threads
329 * participating in this io share the same session.
331 int (*coo_io_init)(const struct lu_env *env,
332 struct cl_object *obj, struct cl_io *io);
334 * Fill portion of \a attr that this layer controls. This method is
335 * called top-to-bottom through all object layers.
337 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
339 * \return 0: to continue
340 * \return +ve: to stop iterating through layers (but 0 is returned
341 * from enclosing cl_object_attr_get())
342 * \return -ve: to signal error
344 int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj,
345 struct cl_attr *attr);
349 * \a valid is a bitmask composed from enum #cl_attr_valid, and
350 * indicating what attributes are to be set.
352 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
354 * \return the same convention as for
355 * cl_object_operations::coo_attr_get() is used.
357 int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj,
358 const struct cl_attr *attr, unsigned int valid);
360 * Update object configuration. Called top-to-bottom to modify object
363 * XXX error conditions and handling.
365 int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj,
366 const struct cl_object_conf *conf);
368 * Glimpse ast. Executed when glimpse ast arrives for a lock on this
369 * object. Layers are supposed to fill parts of \a lvb that will be
370 * shipped to the glimpse originator as a glimpse result.
372 * \see vvp_object_glimpse(), lovsub_object_glimpse(),
373 * \see osc_object_glimpse()
375 int (*coo_glimpse)(const struct lu_env *env,
376 const struct cl_object *obj, struct ost_lvb *lvb);
378 * Object prune method. Called when the layout is going to change on
379 * this object, therefore each layer has to clean up their cache,
380 * mainly pages and locks.
382 int (*coo_prune)(const struct lu_env *env, struct cl_object *obj);
384 * Object getstripe method.
386 int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj,
387 struct lov_user_md __user *lum);
389 * Get FIEMAP mapping from the object.
391 int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj,
392 struct ll_fiemap_info_key *fmkey,
393 struct fiemap *fiemap, size_t *buflen);
395 * Get layout and generation of the object.
397 int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj,
398 struct cl_layout *layout);
400 * Get maximum size of the object.
402 loff_t (*coo_maxbytes)(struct cl_object *obj);
404 * Set request attributes.
406 void (*coo_req_attr_set)(const struct lu_env *env,
407 struct cl_object *obj,
408 struct cl_req_attr *attr);
412 * Extended header for client object.
414 struct cl_object_header {
415 /** Standard lu_object_header. cl_object::co_lu::lo_header points
418 struct lu_object_header coh_lu;
421 * Parent object. It is assumed that an object has a well-defined
422 * parent, but not a well-defined child (there may be multiple
423 * sub-objects, for the same top-object). cl_object_header::coh_parent
424 * field allows certain code to be written generically, without
425 * limiting possible cl_object layouts unduly.
427 struct cl_object_header *coh_parent;
429 * Protects consistency between cl_attr of parent object and
430 * attributes of sub-objects, that the former is calculated ("merged")
433 * \todo XXX this can be read/write lock if needed.
435 spinlock_t coh_attr_guard;
437 * Size of cl_page + page slices
439 unsigned short coh_page_bufsize;
441 * Number of objects above this one: 0 for a top-object, 1 for its
444 unsigned char coh_nesting;
448 * Helper macro: iterate over all layers of the object \a obj, assigning every
449 * layer top-to-bottom to \a slice.
451 #define cl_object_for_each(slice, obj) \
452 list_for_each_entry((slice), \
453 &(obj)->co_lu.lo_header->loh_layers, \
456 * Helper macro: iterate over all layers of the object \a obj, assigning every
457 * layer bottom-to-top to \a slice.
459 #define cl_object_for_each_reverse(slice, obj) \
460 list_for_each_entry_reverse((slice), \
461 &(obj)->co_lu.lo_header->loh_layers, \
465 #define CL_PAGE_EOF ((pgoff_t)~0ull)
467 /** \addtogroup cl_page cl_page
472 * Layered client page.
474 * cl_page: represents a portion of a file, cached in the memory. All pages
475 * of the given file are of the same size, and are kept in the radix tree
476 * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects
477 * of the top-level file object are first class cl_objects, they have their
478 * own radix trees of pages and hence page is implemented as a sequence of
479 * struct cl_pages's, linked into double-linked list through
480 * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the
481 * corresponding radix tree at the corresponding logical offset.
483 * cl_page is associated with VM page of the hosting environment (struct
484 * page in Linux kernel, for example), struct page. It is assumed, that this
485 * association is implemented by one of cl_page layers (top layer in the
486 * current design) that
488 * - intercepts per-VM-page call-backs made by the environment (e.g.,
491 * - translates state (page flag bits) and locking between lustre and
494 * The association between cl_page and struct page is immutable and
495 * established when cl_page is created.
497 * cl_page can be "owned" by a particular cl_io (see below), guaranteeing
498 * this io an exclusive access to this page w.r.t. other io attempts and
499 * various events changing page state (such as transfer completion, or
500 * eviction of the page from the memory). Note, that in general cl_io
501 * cannot be identified with a particular thread, and page ownership is not
502 * exactly equal to the current thread holding a lock on the page. Layer
503 * implementing association between cl_page and struct page has to implement
504 * ownership on top of available synchronization mechanisms.
506 * While lustre client maintains the notion of an page ownership by io,
507 * hosting MM/VM usually has its own page concurrency control
508 * mechanisms. For example, in Linux, page access is synchronized by the
509 * per-page PG_locked bit-lock, and generic kernel code (generic_file_*())
510 * takes care to acquire and release such locks as necessary around the
511 * calls to the file system methods (->readpage(), ->prepare_write(),
512 * ->commit_write(), etc.). This leads to the situation when there are two
513 * different ways to own a page in the client:
515 * - client code explicitly and voluntary owns the page (cl_page_own());
517 * - VM locks a page and then calls the client, that has "to assume"
518 * the ownership from the VM (cl_page_assume()).
520 * Dual methods to release ownership are cl_page_disown() and
521 * cl_page_unassume().
523 * cl_page is reference counted (cl_page::cp_ref). When reference counter
524 * drops to 0, the page is returned to the cache, unless it is in
525 * cl_page_state::CPS_FREEING state, in which case it is immediately
528 * The general logic guaranteeing the absence of "existential races" for
529 * pages is the following:
531 * - there are fixed known ways for a thread to obtain a new reference
534 * - by doing a lookup in the cl_object radix tree, protected by the
537 * - by starting from VM-locked struct page and following some
538 * hosting environment method (e.g., following ->private pointer in
539 * the case of Linux kernel), see cl_vmpage_page();
541 * - when the page enters cl_page_state::CPS_FREEING state, all these
542 * ways are severed with the proper synchronization
543 * (cl_page_delete());
545 * - entry into cl_page_state::CPS_FREEING is serialized by the VM page
548 * - no new references to the page in cl_page_state::CPS_FREEING state
549 * are allowed (checked in cl_page_get()).
551 * Together this guarantees that when last reference to a
552 * cl_page_state::CPS_FREEING page is released, it is safe to destroy the
553 * page, as neither references to it can be acquired at that point, nor
556 * cl_page is a state machine. States are enumerated in enum
557 * cl_page_state. Possible state transitions are enumerated in
558 * cl_page_state_set(). State transition process (i.e., actual changing of
559 * cl_page::cp_state field) is protected by the lock on the underlying VM
562 * Linux Kernel implementation.
564 * Binding between cl_page and struct page (which is a typedef for
565 * struct page) is implemented in the vvp layer. cl_page is attached to the
566 * ->private pointer of the struct page, together with the setting of
567 * PG_private bit in page->flags, and acquiring additional reference on the
568 * struct page (much like struct buffer_head, or any similar file system
569 * private data structures).
571 * PG_locked lock is used to implement both ownership and transfer
572 * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}}
573 * states. No additional references are acquired for the duration of the
576 * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where
577 * write-out is "protected" by the special PG_writeback bit.
581 * States of cl_page. cl_page.c assumes particular order here.
583 * The page state machine is rather crude, as it doesn't recognize finer page
584 * states like "dirty" or "up to date". This is because such states are not
585 * always well defined for the whole stack (see, for example, the
586 * implementation of the read-ahead, that hides page up-to-dateness to track
587 * cache hits accurately). Such sub-states are maintained by the layers that
588 * are interested in them.
592 * Page is in the cache, un-owned. Page leaves cached state in the
595 * - [cl_page_state::CPS_OWNED] io comes across the page and
598 * - [cl_page_state::CPS_PAGEOUT] page is dirty, the
599 * req-formation engine decides that it wants to include this page
600 * into an RPC being constructed, and yanks it from the cache;
602 * - [cl_page_state::CPS_FREEING] VM callback is executed to
603 * evict the page form the memory;
605 * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL
609 * Page is exclusively owned by some cl_io. Page may end up in this
610 * state as a result of
612 * - io creating new page and immediately owning it;
614 * - [cl_page_state::CPS_CACHED] io finding existing cached page
617 * - [cl_page_state::CPS_OWNED] io finding existing owned page
618 * and waiting for owner to release the page;
620 * Page leaves owned state in the following cases:
622 * - [cl_page_state::CPS_CACHED] io decides to leave the page in
623 * the cache, doing nothing;
625 * - [cl_page_state::CPS_PAGEIN] io starts read transfer for
628 * - [cl_page_state::CPS_PAGEOUT] io starts immediate write
629 * transfer for this page;
631 * - [cl_page_state::CPS_FREEING] io decides to destroy this
632 * page (e.g., as part of truncate or extent lock cancellation).
634 * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL
638 * Page is being written out, as a part of a transfer. This state is
639 * entered when req-formation logic decided that it wants this page to
640 * be sent through the wire _now_. Specifically, it means that once
641 * this state is achieved, transfer completion handler (with either
642 * success or failure indication) is guaranteed to be executed against
643 * this page independently of any locks and any scheduling decisions
644 * made by the hosting environment (that effectively means that the
645 * page is never put into cl_page_state::CPS_PAGEOUT state "in
646 * advance". This property is mentioned, because it is important when
647 * reasoning about possible dead-locks in the system). The page can
648 * enter this state as a result of
650 * - [cl_page_state::CPS_OWNED] an io requesting an immediate
651 * write-out of this page, or
653 * - [cl_page_state::CPS_CACHED] req-forming engine deciding
654 * that it has enough dirty pages cached to issue a "good"
657 * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer
658 * is completed---it is moved into cl_page_state::CPS_CACHED state.
660 * Underlying VM page is locked for the duration of transfer.
662 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
666 * Page is being read in, as a part of a transfer. This is quite
667 * similar to the cl_page_state::CPS_PAGEOUT state, except that
668 * read-in is always "immediate"---there is no such thing a sudden
669 * construction of read request from cached, presumably not up to date,
672 * Underlying VM page is locked for the duration of transfer.
674 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
678 * Page is being destroyed. This state is entered when client decides
679 * that page has to be deleted from its host object, as, e.g., a part
682 * Once this state is reached, there is no way to escape it.
684 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL
691 /** Host page, the page is from the host inode which the cl_page
696 /** Transient page, the transient cl_page is used to bind a cl_page
697 * to vmpage which is not belonging to the same object of cl_page.
698 * it is used in DirectIO and lockless IO.
704 * Fields are protected by the lock on struct page, except for atomics and
707 * \invariant Data type invariants are in cl_page_invariant(). Basically:
708 * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked
709 * list, consistent with the parent/child pointers in the cl_page::cp_obj and
710 * cl_page::cp_owner (when set).
713 /** Reference counter. */
715 /** An object this page is a part of. Immutable after creation. */
716 struct cl_object *cp_obj;
718 struct page *cp_vmpage;
719 /** Linkage of pages within group. Pages must be owned */
720 struct list_head cp_batch;
721 /** List of slices. Immutable after creation. */
722 struct list_head cp_layers;
724 * Page state. This field is const to avoid accidental update, it is
725 * modified only internally within cl_page.c. Protected by a VM lock.
727 const enum cl_page_state cp_state;
729 * Page type. Only CPT_TRANSIENT is used so far. Immutable after
732 enum cl_page_type cp_type;
735 * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned
736 * by sub-io. Protected by a VM lock.
738 struct cl_io *cp_owner;
739 /** List of references to this page, for debugging. */
740 struct lu_ref cp_reference;
741 /** Link to an object, for debugging. */
742 struct lu_ref_link cp_obj_ref;
743 /** Link to a queue, for debugging. */
744 struct lu_ref_link cp_queue_ref;
745 /** Assigned if doing a sync_io */
746 struct cl_sync_io *cp_sync_io;
750 * Per-layer part of cl_page.
752 * \see vvp_page, lov_page, osc_page
754 struct cl_page_slice {
755 struct cl_page *cpl_page;
758 * Object slice corresponding to this page slice. Immutable after
761 struct cl_object *cpl_obj;
762 const struct cl_page_operations *cpl_ops;
763 /** Linkage into cl_page::cp_layers. Immutable after creation. */
764 struct list_head cpl_linkage;
768 * Lock mode. For the client extent locks.
779 * Requested transfer type.
788 * Per-layer page operations.
790 * Methods taking an \a io argument are for the activity happening in the
791 * context of given \a io. Page is assumed to be owned by that io, except for
792 * the obvious cases (like cl_page_operations::cpo_own()).
794 * \see vvp_page_ops, lov_page_ops, osc_page_ops
796 struct cl_page_operations {
798 * cl_page<->struct page methods. Only one layer in the stack has to
799 * implement these. Current code assumes that this functionality is
800 * provided by the topmost layer, see cl_page_disown0() as an example.
804 * Called when \a io acquires this page into the exclusive
805 * ownership. When this method returns, it is guaranteed that the is
806 * not owned by other io, and no transfer is going on against
810 * \see vvp_page_own(), lov_page_own()
812 int (*cpo_own)(const struct lu_env *env,
813 const struct cl_page_slice *slice,
814 struct cl_io *io, int nonblock);
815 /** Called when ownership it yielded. Optional.
817 * \see cl_page_disown()
818 * \see vvp_page_disown()
820 void (*cpo_disown)(const struct lu_env *env,
821 const struct cl_page_slice *slice, struct cl_io *io);
823 * Called for a page that is already "owned" by \a io from VM point of
826 * \see cl_page_assume()
827 * \see vvp_page_assume(), lov_page_assume()
829 void (*cpo_assume)(const struct lu_env *env,
830 const struct cl_page_slice *slice, struct cl_io *io);
831 /** Dual to cl_page_operations::cpo_assume(). Optional. Called
832 * bottom-to-top when IO releases a page without actually unlocking
835 * \see cl_page_unassume()
836 * \see vvp_page_unassume()
838 void (*cpo_unassume)(const struct lu_env *env,
839 const struct cl_page_slice *slice,
842 * Announces whether the page contains valid data or not by \a uptodate.
844 * \see cl_page_export()
845 * \see vvp_page_export()
847 void (*cpo_export)(const struct lu_env *env,
848 const struct cl_page_slice *slice, int uptodate);
850 * Checks whether underlying VM page is locked (in the suitable
851 * sense). Used for assertions.
853 * \retval -EBUSY: page is protected by a lock of a given mode;
854 * \retval -ENODATA: page is not protected by a lock;
855 * \retval 0: this layer cannot decide. (Should never happen.)
857 int (*cpo_is_vmlocked)(const struct lu_env *env,
858 const struct cl_page_slice *slice);
864 * Called when page is truncated from the object. Optional.
866 * \see cl_page_discard()
867 * \see vvp_page_discard(), osc_page_discard()
869 void (*cpo_discard)(const struct lu_env *env,
870 const struct cl_page_slice *slice,
873 * Called when page is removed from the cache, and is about to being
874 * destroyed. Optional.
876 * \see cl_page_delete()
877 * \see vvp_page_delete(), osc_page_delete()
879 void (*cpo_delete)(const struct lu_env *env,
880 const struct cl_page_slice *slice);
881 /** Destructor. Frees resources and slice itself. */
882 void (*cpo_fini)(const struct lu_env *env,
883 struct cl_page_slice *slice);
885 * Optional debugging helper. Prints given page slice.
887 * \see cl_page_print()
889 int (*cpo_print)(const struct lu_env *env,
890 const struct cl_page_slice *slice,
891 void *cookie, lu_printer_t p);
900 * Request type dependent vector of operations.
902 * Transfer operations depend on transfer mode (cl_req_type). To avoid
903 * passing transfer mode to each and every of these methods, and to
904 * avoid branching on request type inside of the methods, separate
905 * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
906 * provided. That is, method invocation usually looks like
908 * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
912 * Called when a page is submitted for a transfer as a part of
915 * \return 0 : page is eligible for submission;
916 * \return -EALREADY : skip this page;
917 * \return -ve : error.
919 * \see cl_page_prep()
921 int (*cpo_prep)(const struct lu_env *env,
922 const struct cl_page_slice *slice,
925 * Completion handler. This is guaranteed to be eventually
926 * fired after cl_page_operations::cpo_prep() or
927 * cl_page_operations::cpo_make_ready() call.
929 * This method can be called in a non-blocking context. It is
930 * guaranteed however, that the page involved and its object
931 * are pinned in memory (and, hence, calling cl_page_put() is
934 * \see cl_page_completion()
936 void (*cpo_completion)(const struct lu_env *env,
937 const struct cl_page_slice *slice,
940 * Called when cached page is about to be added to the
941 * ptlrpc request as a part of req formation.
943 * \return 0 : proceed with this page;
944 * \return -EAGAIN : skip this page;
945 * \return -ve : error.
947 * \see cl_page_make_ready()
949 int (*cpo_make_ready)(const struct lu_env *env,
950 const struct cl_page_slice *slice);
953 * Tell transfer engine that only [to, from] part of a page should be
956 * This is used for immediate transfers.
958 * \todo XXX this is not very good interface. It would be much better
959 * if all transfer parameters were supplied as arguments to
960 * cl_io_operations::cio_submit() call, but it is not clear how to do
961 * this for page queues.
963 * \see cl_page_clip()
965 void (*cpo_clip)(const struct lu_env *env,
966 const struct cl_page_slice *slice,
969 * \pre the page was queued for transferring.
970 * \post page is removed from client's pending list, or -EBUSY
971 * is returned if it has already been in transferring.
973 * This is one of seldom page operation which is:
974 * 0. called from top level;
975 * 1. don't have vmpage locked;
976 * 2. every layer should synchronize execution of its ->cpo_cancel()
977 * with completion handlers. Osc uses client obd lock for this
978 * purpose. Based on there is no vvp_page_cancel and
979 * lov_page_cancel(), cpo_cancel is defacto protected by client lock.
981 * \see osc_page_cancel().
983 int (*cpo_cancel)(const struct lu_env *env,
984 const struct cl_page_slice *slice);
986 * Write out a page by kernel. This is only called by ll_writepage
989 * \see cl_page_flush()
991 int (*cpo_flush)(const struct lu_env *env,
992 const struct cl_page_slice *slice,
998 * Helper macro, dumping detailed information about \a page into a log.
1000 #define CL_PAGE_DEBUG(mask, env, page, format, ...) \
1002 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1003 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1004 cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
1005 CDEBUG(mask, format, ## __VA_ARGS__); \
1010 * Helper macro, dumping shorter information about \a page into a log.
1012 #define CL_PAGE_HEADER(mask, env, page, format, ...) \
1014 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1015 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1016 cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
1017 CDEBUG(mask, format, ## __VA_ARGS__); \
1021 static inline struct page *cl_page_vmpage(struct cl_page *page)
1023 LASSERT(page->cp_vmpage);
1024 return page->cp_vmpage;
1028 * Check if a cl_page is in use.
1030 * Client cache holds a refcount, this refcount will be dropped when
1031 * the page is taken out of cache, see vvp_page_delete().
1033 static inline bool __page_in_use(const struct cl_page *page, int refc)
1035 return (atomic_read(&page->cp_ref) > refc + 1);
1039 * Caller itself holds a refcount of cl_page.
1041 #define cl_page_in_use(pg) __page_in_use(pg, 1)
1043 * Caller doesn't hold a refcount.
1045 #define cl_page_in_use_noref(pg) __page_in_use(pg, 0)
1049 /** \addtogroup cl_lock cl_lock
1054 * Extent locking on the client.
1058 * The locking model of the new client code is built around
1062 * data-type representing an extent lock on a regular file. cl_lock is a
1063 * layered object (much like cl_object and cl_page), it consists of a header
1064 * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
1065 * cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
1067 * Typical cl_lock consists of the two layers:
1069 * - vvp_lock (vvp specific data), and
1070 * - lov_lock (lov specific data).
1072 * lov_lock contains an array of sub-locks. Each of these sub-locks is a
1073 * normal cl_lock: it has a header (struct cl_lock) and a list of layers:
1075 * - lovsub_lock, and
1078 * Each sub-lock is associated with a cl_object (representing stripe
1079 * sub-object or the file to which top-level cl_lock is associated to), and is
1080 * linked into that cl_object::coh_locks. In this respect cl_lock is similar to
1081 * cl_object (that at lov layer also fans out into multiple sub-objects), and
1082 * is different from cl_page, that doesn't fan out (there is usually exactly
1083 * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
1084 * a "top-lock" and its lovsub-osc portion a "sub-lock".
1088 * cl_lock is a cacheless data container for the requirements of locks to
1089 * complete the IO. cl_lock is created before I/O starts and destroyed when the
1092 * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
1093 * to cl_lock at OSC layer. LDLM lock is still cacheable.
1095 * INTERFACE AND USAGE
1097 * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
1098 * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
1099 * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
1100 * consists of multiple sub cl_locks, each sub locks will be enqueued
1101 * correspondingly. At OSC layer, the lock enqueue request will tend to reuse
1102 * cached LDLM lock; otherwise a new LDLM lock will have to be requested from
1105 * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
1106 * method will be called for each layer to release the resource held by this
1107 * lock. At OSC layer, the reference count of LDLM lock, which is held at
1108 * clo_enqueue time, is released.
1110 * LDLM lock can only be canceled if there is no cl_lock using it.
1112 * Overall process of the locking during IO operation is as following:
1114 * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
1115 * is called on each layer. Responsibility of this method is to add locks,
1116 * needed by a given layer into cl_io.ci_lockset.
1118 * - once locks for all layers were collected, they are sorted to avoid
1119 * dead-locks (cl_io_locks_sort()), and enqueued.
1121 * - when all locks are acquired, IO is performed;
1123 * - locks are released after IO is complete.
1125 * Striping introduces major additional complexity into locking. The
1126 * fundamental problem is that it is generally unsafe to actively use (hold)
1127 * two locks on the different OST servers at the same time, as this introduces
1128 * inter-server dependency and can lead to cascading evictions.
1130 * Basic solution is to sub-divide large read/write IOs into smaller pieces so
1131 * that no multi-stripe locks are taken (note that this design abandons POSIX
1132 * read/write semantics). Such pieces ideally can be executed concurrently. At
1133 * the same time, certain types of IO cannot be sub-divived, without
1134 * sacrificing correctness. This includes:
1136 * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
1139 * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
1141 * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
1142 * buf is a part of memory mapped Lustre file, a lock or locks protecting buf
1143 * has to be held together with the usual lock on [offset, offset + count].
1145 * Interaction with DLM
1147 * In the expected setup, cl_lock is ultimately backed up by a collection of
1148 * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
1149 * implemented in osc layer, that also matches DLM events (ASTs, cancellation,
1150 * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
1151 * description of interaction with DLM.
1157 struct cl_lock_descr {
1158 /** Object this lock is granted for. */
1159 struct cl_object *cld_obj;
1160 /** Index of the first page protected by this lock. */
1162 /** Index of the last page (inclusive) protected by this lock. */
1164 /** Group ID, for group lock */
1167 enum cl_lock_mode cld_mode;
1169 * flags to enqueue lock. A combination of bit-flags from
1170 * enum cl_enq_flags.
1172 __u32 cld_enq_flags;
1175 #define DDESCR "%s(%d):[%lu, %lu]:%x"
1176 #define PDESCR(descr) \
1177 cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
1178 (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
1180 const char *cl_lock_mode_name(const enum cl_lock_mode mode);
1183 * Layered client lock.
1186 /** List of slices. Immutable after creation. */
1187 struct list_head cll_layers;
1188 /** lock attribute, extent, cl_object, etc. */
1189 struct cl_lock_descr cll_descr;
1193 * Per-layer part of cl_lock
1195 * \see vvp_lock, lov_lock, lovsub_lock, osc_lock
1197 struct cl_lock_slice {
1198 struct cl_lock *cls_lock;
1199 /** Object slice corresponding to this lock slice. Immutable after
1202 struct cl_object *cls_obj;
1203 const struct cl_lock_operations *cls_ops;
1204 /** Linkage into cl_lock::cll_layers. Immutable after creation. */
1205 struct list_head cls_linkage;
1210 * \see vvp_lock_ops, lov_lock_ops, lovsub_lock_ops, osc_lock_ops
1212 struct cl_lock_operations {
1215 * Attempts to enqueue the lock. Called top-to-bottom.
1217 * \retval 0 this layer has enqueued the lock successfully
1218 * \retval >0 this layer has enqueued the lock, but need to wait on
1219 * @anchor for resources
1220 * \retval -ve failure
1222 * \see vvp_lock_enqueue(), lov_lock_enqueue(), lovsub_lock_enqueue(),
1223 * \see osc_lock_enqueue()
1225 int (*clo_enqueue)(const struct lu_env *env,
1226 const struct cl_lock_slice *slice,
1227 struct cl_io *io, struct cl_sync_io *anchor);
1229 * Cancel a lock, release its DLM lock ref, while does not cancel the
1232 void (*clo_cancel)(const struct lu_env *env,
1233 const struct cl_lock_slice *slice);
1236 * Destructor. Frees resources and the slice.
1238 * \see vvp_lock_fini(), lov_lock_fini(), lovsub_lock_fini(),
1239 * \see osc_lock_fini()
1241 void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
1243 * Optional debugging helper. Prints given lock slice.
1245 int (*clo_print)(const struct lu_env *env,
1246 void *cookie, lu_printer_t p,
1247 const struct cl_lock_slice *slice);
1250 #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
1252 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1254 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1255 cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
1256 CDEBUG(mask, format, ## __VA_ARGS__); \
1260 #define CL_LOCK_ASSERT(expr, env, lock) do { \
1264 CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
1270 /** \addtogroup cl_page_list cl_page_list
1271 * Page list used to perform collective operations on a group of pages.
1273 * Pages are added to the list one by one. cl_page_list acquires a reference
1274 * for every page in it. Page list is used to perform collective operations on
1277 * - submit pages for an immediate transfer,
1279 * - own pages on behalf of certain io (waiting for each page in turn),
1283 * When list is finalized, it releases references on all pages it still has.
1285 * \todo XXX concurrency control.
1289 struct cl_page_list {
1291 struct list_head pl_pages;
1292 struct task_struct *pl_owner;
1296 * A 2-queue of pages. A convenience data-type for common use case, 2-queue
1297 * contains an incoming page list and an outgoing page list.
1300 struct cl_page_list c2_qin;
1301 struct cl_page_list c2_qout;
1304 /** @} cl_page_list */
1306 /** \addtogroup cl_io cl_io
1312 * cl_io represents a high level I/O activity like
1313 * read(2)/write(2)/truncate(2) system call, or cancellation of an extent
1316 * cl_io is a layered object, much like cl_{object,page,lock} but with one
1317 * important distinction. We want to minimize number of calls to the allocator
1318 * in the fast path, e.g., in the case of read(2) when everything is cached:
1319 * client already owns the lock over region being read, and data are cached
1320 * due to read-ahead. To avoid allocation of cl_io layers in such situations,
1321 * per-layer io state is stored in the session, associated with the io, see
1322 * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
1323 * by using free-lists, see cl_env_get().
1325 * There is a small predefined number of possible io types, enumerated in enum
1328 * cl_io is a state machine, that can be advanced concurrently by the multiple
1329 * threads. It is up to these threads to control the concurrency and,
1330 * specifically, to detect when io is done, and its state can be safely
1333 * For read/write io overall execution plan is as following:
1335 * (0) initialize io state through all layers;
1337 * (1) loop: prepare chunk of work to do
1339 * (2) call all layers to collect locks they need to process current chunk
1341 * (3) sort all locks to avoid dead-locks, and acquire them
1343 * (4) process the chunk: call per-page methods
1344 * cl_io_operations::cio_prepare_write(),
1345 * cl_io_operations::cio_commit_write() for write)
1351 * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
1352 * address allocation efficiency issues mentioned above), and returns with the
1353 * special error condition from per-page method when current sub-io has to
1354 * block. This causes io loop to be repeated, and lov switches to the next
1355 * sub-io in its cl_io_operations::cio_iter_init() implementation.
1360 /** read system call */
1362 /** write system call */
1364 /** truncate, utime system calls */
1366 /** get data version */
1369 * page fault handling
1373 * fsync system call handling
1374 * To write out a range of file
1378 * Miscellaneous io. This is used for occasional io activity that
1379 * doesn't fit into other types. Currently this is used for:
1381 * - cancellation of an extent lock. This io exists as a context
1382 * to write dirty pages from under the lock being canceled back
1385 * - VM induced page write-out. An io context for writing page out
1386 * for memory cleansing;
1388 * - glimpse. An io context to acquire glimpse lock.
1390 * - grouplock. An io context to acquire group lock.
1392 * CIT_MISC io is used simply as a context in which locks and pages
1393 * are manipulated. Such io has no internal "process", that is,
1394 * cl_io_loop() is never called for it.
1401 * States of cl_io state machine
1404 /** Not initialized. */
1408 /** IO iteration started. */
1412 /** Actual IO is in progress. */
1414 /** IO for the current iteration finished. */
1416 /** Locks released. */
1418 /** Iteration completed. */
1420 /** cl_io finalized. */
1425 * IO state private for a layer.
1427 * This is usually embedded into layer session data, rather than allocated
1430 * \see vvp_io, lov_io, osc_io
1432 struct cl_io_slice {
1433 struct cl_io *cis_io;
1434 /** corresponding object slice. Immutable after creation. */
1435 struct cl_object *cis_obj;
1436 /** io operations. Immutable after creation. */
1437 const struct cl_io_operations *cis_iop;
1439 * linkage into a list of all slices for a given cl_io, hanging off
1440 * cl_io::ci_layers. Immutable after creation.
1442 struct list_head cis_linkage;
1445 typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
1448 struct cl_read_ahead {
1450 * Maximum page index the readahead window will end.
1451 * This is determined DLM lock coverage, RPC and stripe boundary.
1452 * cra_end is included.
1455 /* optimal RPC size for this read, by pages */
1456 unsigned long cra_rpc_size;
1458 * Release callback. If readahead holds resources underneath, this
1459 * function should be called to release it.
1461 void (*cra_release)(const struct lu_env *env, void *cbdata);
1462 /* Callback data for cra_release routine */
1466 static inline void cl_read_ahead_release(const struct lu_env *env,
1467 struct cl_read_ahead *ra)
1469 if (ra->cra_release)
1470 ra->cra_release(env, ra->cra_cbdata);
1471 memset(ra, 0, sizeof(*ra));
1475 * Per-layer io operations.
1476 * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
1478 struct cl_io_operations {
1480 * Vector of io state transition methods for every io type.
1482 * \see cl_page_operations::io
1486 * Prepare io iteration at a given layer.
1488 * Called top-to-bottom at the beginning of each iteration of
1489 * "io loop" (if it makes sense for this type of io). Here
1490 * layer selects what work it will do during this iteration.
1492 * \see cl_io_operations::cio_iter_fini()
1494 int (*cio_iter_init)(const struct lu_env *env,
1495 const struct cl_io_slice *slice);
1497 * Finalize io iteration.
1499 * Called bottom-to-top at the end of each iteration of "io
1500 * loop". Here layers can decide whether IO has to be
1503 * \see cl_io_operations::cio_iter_init()
1505 void (*cio_iter_fini)(const struct lu_env *env,
1506 const struct cl_io_slice *slice);
1508 * Collect locks for the current iteration of io.
1510 * Called top-to-bottom to collect all locks necessary for
1511 * this iteration. This methods shouldn't actually enqueue
1512 * anything, instead it should post a lock through
1513 * cl_io_lock_add(). Once all locks are collected, they are
1514 * sorted and enqueued in the proper order.
1516 int (*cio_lock)(const struct lu_env *env,
1517 const struct cl_io_slice *slice);
1519 * Finalize unlocking.
1521 * Called bottom-to-top to finish layer specific unlocking
1522 * functionality, after generic code released all locks
1523 * acquired by cl_io_operations::cio_lock().
1525 void (*cio_unlock)(const struct lu_env *env,
1526 const struct cl_io_slice *slice);
1528 * Start io iteration.
1530 * Once all locks are acquired, called top-to-bottom to
1531 * commence actual IO. In the current implementation,
1532 * top-level vvp_io_{read,write}_start() does all the work
1533 * synchronously by calling generic_file_*(), so other layers
1534 * are called when everything is done.
1536 int (*cio_start)(const struct lu_env *env,
1537 const struct cl_io_slice *slice);
1539 * Called top-to-bottom at the end of io loop. Here layer
1540 * might wait for an unfinished asynchronous io.
1542 void (*cio_end)(const struct lu_env *env,
1543 const struct cl_io_slice *slice);
1545 * Called bottom-to-top to notify layers that read/write IO
1546 * iteration finished, with \a nob bytes transferred.
1548 void (*cio_advance)(const struct lu_env *env,
1549 const struct cl_io_slice *slice,
1552 * Called once per io, bottom-to-top to release io resources.
1554 void (*cio_fini)(const struct lu_env *env,
1555 const struct cl_io_slice *slice);
1559 * Submit pages from \a queue->c2_qin for IO, and move
1560 * successfully submitted pages into \a queue->c2_qout. Return
1561 * non-zero if failed to submit even the single page. If
1562 * submission failed after some pages were moved into \a
1563 * queue->c2_qout, completion callback with non-zero ioret is
1566 int (*cio_submit)(const struct lu_env *env,
1567 const struct cl_io_slice *slice,
1568 enum cl_req_type crt,
1569 struct cl_2queue *queue);
1571 * Queue async page for write.
1572 * The difference between cio_submit and cio_queue is that
1573 * cio_submit is for urgent request.
1575 int (*cio_commit_async)(const struct lu_env *env,
1576 const struct cl_io_slice *slice,
1577 struct cl_page_list *queue, int from, int to,
1580 * Decide maximum read ahead extent
1582 * \pre io->ci_type == CIT_READ
1584 int (*cio_read_ahead)(const struct lu_env *env,
1585 const struct cl_io_slice *slice,
1586 pgoff_t start, struct cl_read_ahead *ra);
1588 * Optional debugging helper. Print given io slice.
1590 int (*cio_print)(const struct lu_env *env, void *cookie,
1591 lu_printer_t p, const struct cl_io_slice *slice);
1595 * Flags to lock enqueue procedure.
1600 * instruct server to not block, if conflicting lock is found. Instead
1601 * -EWOULDBLOCK is returned immediately.
1603 CEF_NONBLOCK = 0x00000001,
1605 * take lock asynchronously (out of order), as it cannot
1606 * deadlock. This is for LDLM_FL_HAS_INTENT locks used for glimpsing.
1608 CEF_ASYNC = 0x00000002,
1610 * tell the server to instruct (though a flag in the blocking ast) an
1611 * owner of the conflicting lock, that it can drop dirty pages
1612 * protected by this lock, without sending them to the server.
1614 CEF_DISCARD_DATA = 0x00000004,
1616 * tell the sub layers that it must be a `real' lock. This is used for
1617 * mmapped-buffer locks and glimpse locks that must be never converted
1618 * into lockless mode.
1620 * \see vvp_mmap_locks(), cl_glimpse_lock().
1622 CEF_MUST = 0x00000008,
1624 * tell the sub layers that never request a `real' lock. This flag is
1625 * not used currently.
1627 * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
1628 * conversion policy: ci_lockreq describes generic information of lock
1629 * requirement for this IO, especially for locks which belong to the
1630 * object doing IO; however, lock itself may have precise requirements
1631 * that are described by the enqueue flags.
1633 CEF_NEVER = 0x00000010,
1635 * for async glimpse lock.
1637 CEF_AGL = 0x00000020,
1639 * enqueue a lock to test DLM lock existence.
1641 CEF_PEEK = 0x00000040,
1643 * Lock match only. Used by group lock in I/O as group lock
1644 * is known to exist.
1646 CEF_LOCK_MATCH = BIT(7),
1648 * mask of enq_flags.
1650 CEF_MASK = 0x000000ff,
1654 * Link between lock and io. Intermediate structure is needed, because the
1655 * same lock can be part of multiple io's simultaneously.
1657 struct cl_io_lock_link {
1658 /** linkage into one of cl_lockset lists. */
1659 struct list_head cill_linkage;
1660 struct cl_lock cill_lock;
1661 /** optional destructor */
1662 void (*cill_fini)(const struct lu_env *env,
1663 struct cl_io_lock_link *link);
1665 #define cill_descr cill_lock.cll_descr
1668 * Lock-set represents a collection of locks, that io needs at a
1669 * time. Generally speaking, client tries to avoid holding multiple locks when
1672 * - holding extent locks over multiple ost's introduces the danger of
1673 * "cascading timeouts";
1675 * - holding multiple locks over the same ost is still dead-lock prone,
1676 * see comment in osc_lock_enqueue(),
1678 * but there are certain situations where this is unavoidable:
1680 * - O_APPEND writes have to take [0, EOF] lock for correctness;
1682 * - truncate has to take [new-size, EOF] lock for correctness;
1684 * - SNS has to take locks across full stripe for correctness;
1686 * - in the case when user level buffer, supplied to {read,write}(file0),
1687 * is a part of a memory mapped lustre file, client has to take a dlm
1688 * locks on file0, and all files that back up the buffer (or a part of
1689 * the buffer, that is being processed in the current chunk, in any
1690 * case, there are situations where at least 2 locks are necessary).
1692 * In such cases we at least try to take locks in the same consistent
1693 * order. To this end, all locks are first collected, then sorted, and then
1697 /** locks to be acquired. */
1698 struct list_head cls_todo;
1699 /** locks acquired. */
1700 struct list_head cls_done;
1704 * Lock requirements(demand) for IO. It should be cl_io_lock_req,
1705 * but 'req' is always to be thought as 'request' :-)
1707 enum cl_io_lock_dmd {
1708 /** Always lock data (e.g., O_APPEND). */
1710 /** Layers are free to decide between local and global locking. */
1712 /** Never lock: there is no cache (e.g., lockless IO). */
1716 enum cl_fsync_mode {
1717 /** start writeback, do not wait for them to finish */
1719 /** start writeback and wait for them to finish */
1721 /** discard all of dirty pages in a specific file range */
1722 CL_FSYNC_DISCARD = 2,
1723 /** start writeback and make sure they have reached storage before
1724 * return. OST_SYNC RPC must be issued and finished
1729 struct cl_io_rw_common {
1738 * cl_io is shared by all threads participating in this IO (in current
1739 * implementation only one thread advances IO, but parallel IO design and
1740 * concurrent copy_*_user() require multiple threads acting on the same IO. It
1741 * is up to these threads to serialize their activities, including updates to
1742 * mutable cl_io fields.
1745 /** type of this IO. Immutable after creation. */
1746 enum cl_io_type ci_type;
1747 /** current state of cl_io state machine. */
1748 enum cl_io_state ci_state;
1749 /** main object this io is against. Immutable after creation. */
1750 struct cl_object *ci_obj;
1752 * Upper layer io, of which this io is a part of. Immutable after
1755 struct cl_io *ci_parent;
1756 /** List of slices. Immutable after creation. */
1757 struct list_head ci_layers;
1758 /** list of locks (to be) acquired by this io. */
1759 struct cl_lockset ci_lockset;
1760 /** lock requirements, this is just a help info for sublayers. */
1761 enum cl_io_lock_dmd ci_lockreq;
1764 struct cl_io_rw_common rd;
1767 struct cl_io_rw_common wr;
1771 struct cl_io_rw_common ci_rw;
1772 struct cl_setattr_io {
1773 struct ost_lvb sa_attr;
1774 unsigned int sa_attr_flags;
1775 unsigned int sa_valid;
1776 int sa_stripe_index;
1777 const struct lu_fid *sa_parent_fid;
1779 struct cl_data_version_io {
1780 u64 dv_data_version;
1783 struct cl_fault_io {
1784 /** page index within file. */
1786 /** bytes valid byte on a faulted page. */
1788 /** writable page? for nopage() only */
1790 /** page of an executable? */
1792 /** page_mkwrite() */
1794 /** resulting page */
1795 struct cl_page *ft_page;
1797 struct cl_fsync_io {
1800 /** file system level fid */
1801 struct lu_fid *fi_fid;
1802 enum cl_fsync_mode fi_mode;
1803 /* how many pages were written/discarded */
1804 unsigned int fi_nr_written;
1807 struct cl_2queue ci_queue;
1810 unsigned int ci_continue:1,
1812 * This io has held grouplock, to inform sublayers that
1813 * don't do lockless i/o.
1817 * The whole IO need to be restarted because layout has been changed
1821 * to not refresh layout - the IO issuer knows that the layout won't
1822 * change(page operations, layout change causes all page to be
1823 * discarded), or it doesn't matter if it changes(sync).
1827 * Check if layout changed after the IO finishes. Mainly for HSM
1828 * requirement. If IO occurs to openning files, it doesn't need to
1829 * verify layout because HSM won't release openning files.
1830 * Right now, only two operations need to verify layout: glimpse
1835 * file is released, restore has to to be triggered by vvp layer
1837 ci_restore_needed:1,
1843 * Number of pages owned by this IO. For invariant checking.
1845 unsigned int ci_owned_nr;
1851 * Per-transfer attributes.
1853 struct cl_req_attr {
1854 enum cl_req_type cra_type;
1856 struct cl_page *cra_page;
1858 /** Generic attributes for the server consumption. */
1859 struct obdo *cra_oa;
1861 char cra_jobid[LUSTRE_JOBID_SIZE];
1864 enum cache_stats_item {
1865 /** how many cache lookups were performed */
1867 /** how many times cache lookup resulted in a hit */
1869 /** how many entities are in the cache right now */
1871 /** how many entities in the cache are actively used (and cannot be
1872 * evicted) right now
1875 /** how many entities were created at all */
1880 #define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
1883 * Stats for a generic cache (similar to inode, lu_object, etc. caches).
1885 struct cache_stats {
1886 const char *cs_name;
1887 atomic_t cs_stats[CS_NR];
1890 /** These are not exported so far */
1891 void cache_stats_init(struct cache_stats *cs, const char *name);
1894 * Client-side site. This represents particular client stack. "Global"
1895 * variables should (directly or indirectly) be added here to allow multiple
1896 * clients to co-exist in the single address space.
1899 struct lu_site cs_lu;
1901 * Statistical counters. Atomics do not scale, something better like
1902 * per-cpu counters is needed.
1904 * These are exported as /sys/kernel/debug/lustre/llite/.../site
1906 * When interpreting keep in mind that both sub-locks (and sub-pages)
1907 * and top-locks (and top-pages) are accounted here.
1909 struct cache_stats cs_pages;
1910 atomic_t cs_pages_state[CPS_NR];
1913 int cl_site_init(struct cl_site *s, struct cl_device *top);
1914 void cl_site_fini(struct cl_site *s);
1915 void cl_stack_fini(const struct lu_env *env, struct cl_device *cl);
1918 * Output client site statistical counters into a buffer. Suitable for
1919 * ll_rd_*()-style functions.
1921 int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
1926 * Type conversion and accessory functions.
1930 static inline struct cl_site *lu2cl_site(const struct lu_site *site)
1932 return container_of(site, struct cl_site, cs_lu);
1935 static inline int lu_device_is_cl(const struct lu_device *d)
1937 return d->ld_type->ldt_tags & LU_DEVICE_CL;
1940 static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
1942 LASSERT(!d || IS_ERR(d) || lu_device_is_cl(d));
1943 return container_of0(d, struct cl_device, cd_lu_dev);
1946 static inline struct lu_device *cl2lu_dev(struct cl_device *d)
1948 return &d->cd_lu_dev;
1951 static inline struct cl_object *lu2cl(const struct lu_object *o)
1953 LASSERT(!o || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
1954 return container_of0(o, struct cl_object, co_lu);
1957 static inline const struct cl_object_conf *
1958 lu2cl_conf(const struct lu_object_conf *conf)
1960 return container_of0(conf, struct cl_object_conf, coc_lu);
1963 static inline struct cl_object *cl_object_next(const struct cl_object *obj)
1965 return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL;
1968 static inline struct cl_device *cl_object_device(const struct cl_object *o)
1970 LASSERT(!o || IS_ERR(o) || lu_device_is_cl(o->co_lu.lo_dev));
1971 return container_of0(o->co_lu.lo_dev, struct cl_device, cd_lu_dev);
1974 static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
1976 return container_of0(h, struct cl_object_header, coh_lu);
1979 static inline struct cl_site *cl_object_site(const struct cl_object *obj)
1981 return lu2cl_site(obj->co_lu.lo_dev->ld_site);
1985 struct cl_object_header *cl_object_header(const struct cl_object *obj)
1987 return luh2coh(obj->co_lu.lo_header);
1990 static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
1992 return lu_device_init(&d->cd_lu_dev, t);
1995 static inline void cl_device_fini(struct cl_device *d)
1997 lu_device_fini(&d->cd_lu_dev);
2000 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
2001 struct cl_object *obj, pgoff_t index,
2002 const struct cl_page_operations *ops);
2003 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
2004 struct cl_object *obj,
2005 const struct cl_lock_operations *ops);
2006 void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
2007 struct cl_object *obj, const struct cl_io_operations *ops);
2010 /** \defgroup cl_object cl_object
2013 struct cl_object *cl_object_top(struct cl_object *o);
2014 struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
2015 const struct lu_fid *fid,
2016 const struct cl_object_conf *c);
2018 int cl_object_header_init(struct cl_object_header *h);
2019 void cl_object_put(const struct lu_env *env, struct cl_object *o);
2020 void cl_object_get(struct cl_object *o);
2021 void cl_object_attr_lock(struct cl_object *o);
2022 void cl_object_attr_unlock(struct cl_object *o);
2023 int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
2024 struct cl_attr *attr);
2025 int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
2026 const struct cl_attr *attr, unsigned int valid);
2027 int cl_object_glimpse(const struct lu_env *env, struct cl_object *obj,
2028 struct ost_lvb *lvb);
2029 int cl_conf_set(const struct lu_env *env, struct cl_object *obj,
2030 const struct cl_object_conf *conf);
2031 int cl_object_prune(const struct lu_env *env, struct cl_object *obj);
2032 void cl_object_kill(const struct lu_env *env, struct cl_object *obj);
2033 int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj,
2034 struct lov_user_md __user *lum);
2035 int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj,
2036 struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap,
2038 int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj,
2039 struct cl_layout *cl);
2040 loff_t cl_object_maxbytes(struct cl_object *obj);
2043 * Returns true, iff \a o0 and \a o1 are slices of the same object.
2045 static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
2047 return cl_object_header(o0) == cl_object_header(o1);
2050 static inline void cl_object_page_init(struct cl_object *clob, int size)
2052 clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
2053 cl_object_header(clob)->coh_page_bufsize += cfs_size_round(size);
2054 WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
2057 static inline void *cl_object_page_slice(struct cl_object *clob,
2058 struct cl_page *page)
2060 return (void *)((char *)page + clob->co_slice_off);
2064 * Return refcount of cl_object.
2066 static inline int cl_object_refc(struct cl_object *clob)
2068 struct lu_object_header *header = clob->co_lu.lo_header;
2070 return atomic_read(&header->loh_ref);
2075 /** \defgroup cl_page cl_page
2085 /* callback of cl_page_gang_lookup() */
2086 struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *obj,
2087 pgoff_t idx, struct page *vmpage,
2088 enum cl_page_type type);
2089 struct cl_page *cl_page_alloc(const struct lu_env *env,
2090 struct cl_object *o, pgoff_t ind,
2091 struct page *vmpage,
2092 enum cl_page_type type);
2093 void cl_page_get(struct cl_page *page);
2094 void cl_page_put(const struct lu_env *env, struct cl_page *page);
2095 void cl_page_print(const struct lu_env *env, void *cookie, lu_printer_t printer,
2096 const struct cl_page *pg);
2097 void cl_page_header_print(const struct lu_env *env, void *cookie,
2098 lu_printer_t printer, const struct cl_page *pg);
2099 struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj);
2101 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
2102 const struct lu_device_type *dtype);
2107 * Functions dealing with the ownership of page by io.
2111 int cl_page_own(const struct lu_env *env,
2112 struct cl_io *io, struct cl_page *page);
2113 int cl_page_own_try(const struct lu_env *env,
2114 struct cl_io *io, struct cl_page *page);
2115 void cl_page_assume(const struct lu_env *env,
2116 struct cl_io *io, struct cl_page *page);
2117 void cl_page_unassume(const struct lu_env *env,
2118 struct cl_io *io, struct cl_page *pg);
2119 void cl_page_disown(const struct lu_env *env,
2120 struct cl_io *io, struct cl_page *page);
2121 void cl_page_disown0(const struct lu_env *env,
2122 struct cl_io *io, struct cl_page *pg);
2123 int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io);
2130 * Functions dealing with the preparation of a page for a transfer, and
2131 * tracking transfer state.
2134 int cl_page_prep(const struct lu_env *env, struct cl_io *io,
2135 struct cl_page *pg, enum cl_req_type crt);
2136 void cl_page_completion(const struct lu_env *env,
2137 struct cl_page *pg, enum cl_req_type crt, int ioret);
2138 int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
2139 enum cl_req_type crt);
2140 int cl_page_cache_add(const struct lu_env *env, struct cl_io *io,
2141 struct cl_page *pg, enum cl_req_type crt);
2142 void cl_page_clip(const struct lu_env *env, struct cl_page *pg,
2144 int cl_page_cancel(const struct lu_env *env, struct cl_page *page);
2145 int cl_page_flush(const struct lu_env *env, struct cl_io *io,
2146 struct cl_page *pg);
2151 * \name helper routines
2152 * Functions to discard, delete and export a cl_page.
2155 void cl_page_discard(const struct lu_env *env, struct cl_io *io,
2156 struct cl_page *pg);
2157 void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
2158 int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg);
2159 void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate);
2160 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx);
2161 pgoff_t cl_index(const struct cl_object *obj, loff_t offset);
2162 size_t cl_page_size(const struct cl_object *obj);
2163 int cl_pages_prune(const struct lu_env *env, struct cl_object *obj);
2165 void cl_lock_print(const struct lu_env *env, void *cookie,
2166 lu_printer_t printer, const struct cl_lock *lock);
2167 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2168 lu_printer_t printer,
2169 const struct cl_lock_descr *descr);
2173 * Data structure managing a client's cached pages. A count of
2174 * "unstable" pages is maintained, and an LRU of clean pages is
2175 * maintained. "unstable" pages are pages pinned by the ptlrpc
2176 * layer for recovery purposes.
2178 struct cl_client_cache {
2180 * # of client cache refcount
2181 * # of users (OSCs) + 2 (held by llite and lov)
2185 * # of threads are doing shrinking
2187 unsigned int ccc_lru_shrinkers;
2189 * # of LRU entries available
2191 atomic_long_t ccc_lru_left;
2193 * List of entities(OSCs) for this LRU cache
2195 struct list_head ccc_lru;
2197 * Max # of LRU entries
2199 unsigned long ccc_lru_max;
2201 * Lock to protect ccc_lru list
2203 spinlock_t ccc_lru_lock;
2205 * Set if unstable check is enabled
2207 unsigned int ccc_unstable_check:1;
2209 * # of unstable pages for this mount point
2211 atomic_long_t ccc_unstable_nr;
2213 * Waitq for awaiting unstable pages to reach zero.
2214 * Used at umounting time and signaled on BRW commit
2216 wait_queue_head_t ccc_unstable_waitq;
2221 * cl_cache functions
2223 struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
2224 void cl_cache_incref(struct cl_client_cache *cache);
2225 void cl_cache_decref(struct cl_client_cache *cache);
2229 /** \defgroup cl_lock cl_lock
2233 int cl_lock_request(const struct lu_env *env, struct cl_io *io,
2234 struct cl_lock *lock);
2235 int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
2236 const struct cl_io *io);
2237 void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
2238 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
2239 const struct lu_device_type *dtype);
2240 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
2241 int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
2242 struct cl_lock *lock, struct cl_sync_io *anchor);
2243 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
2247 /** \defgroup cl_io cl_io
2251 int cl_io_init(const struct lu_env *env, struct cl_io *io,
2252 enum cl_io_type iot, struct cl_object *obj);
2253 int cl_io_sub_init(const struct lu_env *env, struct cl_io *io,
2254 enum cl_io_type iot, struct cl_object *obj);
2255 int cl_io_rw_init(const struct lu_env *env, struct cl_io *io,
2256 enum cl_io_type iot, loff_t pos, size_t count);
2257 int cl_io_loop(const struct lu_env *env, struct cl_io *io);
2259 void cl_io_fini(const struct lu_env *env, struct cl_io *io);
2260 int cl_io_iter_init(const struct lu_env *env, struct cl_io *io);
2261 void cl_io_iter_fini(const struct lu_env *env, struct cl_io *io);
2262 int cl_io_lock(const struct lu_env *env, struct cl_io *io);
2263 void cl_io_unlock(const struct lu_env *env, struct cl_io *io);
2264 int cl_io_start(const struct lu_env *env, struct cl_io *io);
2265 void cl_io_end(const struct lu_env *env, struct cl_io *io);
2266 int cl_io_lock_add(const struct lu_env *env, struct cl_io *io,
2267 struct cl_io_lock_link *link);
2268 int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
2269 struct cl_lock_descr *descr);
2270 int cl_io_submit_rw(const struct lu_env *env, struct cl_io *io,
2271 enum cl_req_type iot, struct cl_2queue *queue);
2272 int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io,
2273 enum cl_req_type iot, struct cl_2queue *queue,
2275 int cl_io_commit_async(const struct lu_env *env, struct cl_io *io,
2276 struct cl_page_list *queue, int from, int to,
2278 int cl_io_read_ahead(const struct lu_env *env, struct cl_io *io,
2279 pgoff_t start, struct cl_read_ahead *ra);
2280 int cl_io_is_going(const struct lu_env *env);
2283 * True, iff \a io is an O_APPEND write(2).
2285 static inline int cl_io_is_append(const struct cl_io *io)
2287 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
2290 static inline int cl_io_is_sync_write(const struct cl_io *io)
2292 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
2295 static inline int cl_io_is_mkwrite(const struct cl_io *io)
2297 return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
2301 * True, iff \a io is a truncate(2).
2303 static inline int cl_io_is_trunc(const struct cl_io *io)
2305 return io->ci_type == CIT_SETATTR &&
2306 (io->u.ci_setattr.sa_valid & ATTR_SIZE);
2309 struct cl_io *cl_io_top(struct cl_io *io);
2311 #define CL_IO_SLICE_CLEAN(foo_io, base) \
2313 typeof(foo_io) __foo_io = (foo_io); \
2315 BUILD_BUG_ON(offsetof(typeof(*__foo_io), base) != 0); \
2316 memset(&__foo_io->base + 1, 0, \
2317 sizeof(*__foo_io) - sizeof(__foo_io->base)); \
2322 /** \defgroup cl_page_list cl_page_list
2327 * Last page in the page list.
2329 static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
2331 LASSERT(plist->pl_nr > 0);
2332 return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
2335 static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
2337 LASSERT(plist->pl_nr > 0);
2338 return list_entry(plist->pl_pages.next, struct cl_page, cp_batch);
2342 * Iterate over pages in a page list.
2344 #define cl_page_list_for_each(page, list) \
2345 list_for_each_entry((page), &(list)->pl_pages, cp_batch)
2348 * Iterate over pages in a page list, taking possible removals into account.
2350 #define cl_page_list_for_each_safe(page, temp, list) \
2351 list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
2353 void cl_page_list_init(struct cl_page_list *plist);
2354 void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page);
2355 void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src,
2356 struct cl_page *page);
2357 void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
2358 struct cl_page *page);
2359 void cl_page_list_splice(struct cl_page_list *list, struct cl_page_list *head);
2360 void cl_page_list_del(const struct lu_env *env, struct cl_page_list *plist,
2361 struct cl_page *page);
2362 void cl_page_list_disown(const struct lu_env *env,
2363 struct cl_io *io, struct cl_page_list *plist);
2364 void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist);
2366 void cl_2queue_init(struct cl_2queue *queue);
2367 void cl_2queue_disown(const struct lu_env *env,
2368 struct cl_io *io, struct cl_2queue *queue);
2369 void cl_2queue_discard(const struct lu_env *env,
2370 struct cl_io *io, struct cl_2queue *queue);
2371 void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue);
2372 void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
2374 /** @} cl_page_list */
2376 void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
2377 struct cl_req_attr *attr);
2379 /** \defgroup cl_sync_io cl_sync_io
2384 * Anchor for synchronous transfer. This is allocated on a stack by thread
2385 * doing synchronous transfer, and a pointer to this structure is set up in
2386 * every page submitted for transfer. Transfer completion routine updates
2387 * anchor and wakes up waiting thread when transfer is complete.
2390 /** number of pages yet to be transferred. */
2391 atomic_t csi_sync_nr;
2394 /** barrier of destroy this structure */
2395 atomic_t csi_barrier;
2396 /** completion to be signaled when transfer is complete. */
2397 wait_queue_head_t csi_waitq;
2398 /** callback to invoke when this IO is finished */
2399 void (*csi_end_io)(const struct lu_env *,
2400 struct cl_sync_io *);
2403 void cl_sync_io_init(struct cl_sync_io *anchor, int nr,
2404 void (*end)(const struct lu_env *, struct cl_sync_io *));
2405 int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
2407 void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
2409 void cl_sync_io_end(const struct lu_env *env, struct cl_sync_io *anchor);
2411 /** @} cl_sync_io */
2413 /** \defgroup cl_env cl_env
2415 * lu_env handling for a client.
2417 * lu_env is an environment within which lustre code executes. Its major part
2418 * is lu_context---a fast memory allocation mechanism that is used to conserve
2419 * precious kernel stack space. Originally lu_env was designed for a server,
2422 * - there is a (mostly) fixed number of threads, and
2424 * - call chains have no non-lustre portions inserted between lustre code.
2426 * On a client both these assumption fails, because every user thread can
2427 * potentially execute lustre code as part of a system call, and lustre calls
2428 * into VFS or MM that call back into lustre.
2430 * To deal with that, cl_env wrapper functions implement the following
2433 * - allocation and destruction of environment is amortized by caching no
2434 * longer used environments instead of destroying them;
2436 * \see lu_env, lu_context, lu_context_key
2440 struct lu_env *cl_env_get(u16 *refcheck);
2441 struct lu_env *cl_env_alloc(u16 *refcheck, __u32 tags);
2442 void cl_env_put(struct lu_env *env, u16 *refcheck);
2443 unsigned int cl_env_cache_purge(unsigned int nr);
2444 struct lu_env *cl_env_percpu_get(void);
2445 void cl_env_percpu_put(struct lu_env *env);
2452 void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
2454 struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
2455 struct lu_device_type *ldt,
2456 struct lu_device *next);
2459 int cl_global_init(void);
2460 void cl_global_fini(void);
2462 #endif /* _LINUX_CL_OBJECT_H */