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13 * General Public License version 2 for more details (a copy is included
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27 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
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31 * This file is part of Lustre, http://www.lustre.org/
32 * Lustre is a trademark of Sun Microsystems, Inc.
35 * This file is part of Lustre, http://www.lustre.org/
36 * Lustre is a trademark of Sun Microsystems, Inc.
38 * Internal interfaces of LOV layer.
40 * Author: Nikita Danilov <nikita.danilov@sun.com>
43 #ifndef LOV_CL_INTERNAL_H
44 #define LOV_CL_INTERNAL_H
47 # include <libcfs/libcfs.h>
49 # include <liblustre.h>
53 #include <cl_object.h>
54 #include "lov_internal.h"
57 * Logical object volume layer. This layer implements data striping (raid0).
59 * At the lov layer top-entity (object, page, lock, io) is connected to one or
60 * more sub-entities: top-object, representing a file is connected to a set of
61 * sub-objects, each representing a stripe, file-level top-lock is connected
62 * to a set of per-stripe sub-locks, top-page is connected to a (single)
63 * sub-page, and a top-level IO is connected to a set of (potentially
64 * concurrent) sub-IO's.
66 * Sub-object, sub-page, and sub-io have well-defined top-object and top-page
67 * respectively, while a single sub-lock can be part of multiple top-locks.
69 * Reference counting models are different for different types of entities:
71 * - top-object keeps a reference to its sub-objects, and destroys them
72 * when it is destroyed.
74 * - top-page keeps a reference to its sub-page, and destroys it when it
77 * - sub-lock keep a reference to its top-locks. Top-lock keeps a
78 * reference (and a hold, see cl_lock_hold()) on its sub-locks when it
79 * actively using them (that is, in cl_lock_state::CLS_QUEUING,
80 * cl_lock_state::CLS_ENQUEUED, cl_lock_state::CLS_HELD states). When
81 * moving into cl_lock_state::CLS_CACHED state, top-lock releases a
82 * hold. From this moment top-lock has only a 'weak' reference to its
83 * sub-locks. This reference is protected by top-lock
84 * cl_lock::cll_guard, and will be automatically cleared by the sub-lock
85 * when the latter is destroyed. When a sub-lock is canceled, a
86 * reference to it is removed from the top-lock array, and top-lock is
87 * moved into CLS_NEW state. It is guaranteed that all sub-locks exist
88 * while their top-lock is in CLS_HELD or CLS_CACHED states.
90 * - IO's are not reference counted.
92 * To implement a connection between top and sub entities, lov layer is split
93 * into two pieces: lov ("upper half"), and lovsub ("bottom half"), both
94 * implementing full set of cl-interfaces. For example, top-object has vvp and
95 * lov layers, and it's sub-object has lovsub and osc layers. lovsub layer is
96 * used to track child-parent relationship.
101 struct lovsub_device;
102 struct lovsub_object;
105 enum lov_device_flags {
106 LOV_DEV_INITIALIZED = 1 << 0
114 * Resources that are used in memory-cleaning path, and whose allocation
115 * cannot fail even when memory is tight. They are preallocated in sufficient
116 * quantities in lov_device::ld_emerg[], and access to them is serialized
117 * lov_device::ld_mutex.
119 struct lov_device_emerg {
121 * Page list used to submit IO when memory is in pressure.
123 struct cl_page_list emrg_page_list;
125 * sub-io's shared by all threads accessing this device when memory is
126 * too low to allocate sub-io's dynamically.
128 struct cl_io emrg_subio;
130 * Environments used by sub-io's in
131 * lov_device_emerg::emrg_subio.
133 struct lu_env *emrg_env;
135 * Refchecks for lov_device_emerg::emrg_env.
144 * XXX Locking of lov-private data is missing.
146 struct cl_device ld_cl;
147 struct lov_obd *ld_lov;
148 /** size of lov_device::ld_target[] array */
150 struct lovsub_device **ld_target;
153 /** Emergency resources used in memory-cleansing paths. */
154 struct lov_device_emerg **ld_emrg;
156 * Serializes access to lov_device::ld_emrg in low-memory
159 cfs_mutex_t ld_mutex;
165 enum lov_layout_type {
166 /** empty file without body */
174 * lov-specific file state.
176 * lov object has particular layout type, determining how top-object is built
177 * on top of sub-objects. Layout type can change dynamically. When this
178 * happens, lov_object::lo_type_guard semaphore is taken in exclusive mode,
179 * all state pertaining to the old layout type is destroyed, and new state is
180 * constructed. All object methods take said semaphore in the shared mode,
181 * providing serialization against transition between layout types.
183 * To avoid multiple `if' or `switch' statements, selecting behavior for the
184 * current layout type, object methods perform double-dispatch, invoking
185 * function corresponding to the current layout type.
188 struct cl_object lo_cl;
190 * Serializes object operations with transitions between layout types.
192 * This semaphore is taken in shared mode by all object methods, and
193 * is taken in exclusive mode when object type is changed.
195 * \see lov_object::lo_type
197 cfs_rw_semaphore_t lo_type_guard;
199 * Type of an object. Protected by lov_object::lo_type_guard.
201 enum lov_layout_type lo_type;
203 union lov_layout_state {
204 struct lov_layout_raid0 {
206 struct lov_stripe_md *lo_lsm;
208 * Array of sub-objects. Allocated when top-object is
209 * created (lov_init_raid0()).
211 * Top-object is a strict master of its sub-objects:
212 * it is created before them, and outlives its
213 * children (this later is necessary so that basic
214 * functions like cl_object_top() always
215 * work). Top-object keeps a reference on every
218 * When top-object is destroyed (lov_delete_raid0())
219 * it releases its reference to a sub-object and waits
220 * until the latter is finally destroyed.
222 struct lovsub_object **lo_sub;
226 cfs_spinlock_t lo_sub_lock;
228 * When this is true, lov_object::lo_attr contains
229 * valid up to date attributes for a top-level
230 * object. This field is reset to 0 when attributes of
231 * any sub-object change.
235 * Cached object attribute, built from sub-object
238 struct cl_attr lo_attr;
240 struct lov_layout_state_empty {
244 * Thread that acquired lov_object::lo_type_guard in an exclusive
247 cfs_task_t *lo_owner;
251 * Flags that top-lock can set on each of its sub-locks.
254 /** Top-lock acquired a hold (cl_lock_hold()) on a sub-lock. */
259 * State lov_lock keeps for each sub-lock.
261 struct lov_lock_sub {
262 /** sub-lock itself */
263 struct lovsub_lock *sub_lock;
264 /** An array of per-sub-lock flags, taken from enum lov_sub_flags */
267 struct cl_lock_descr sub_descr;
268 struct cl_lock_descr sub_got;
272 * lov-specific lock state.
275 struct cl_lock_slice lls_cl;
276 /** Number of sub-locks in this lock */
279 * Number of existing sub-locks.
281 unsigned lls_nr_filled;
283 * Set when sub-lock was canceled, while top-lock was being
286 int lls_cancel_race:1;
288 * An array of sub-locks
290 * There are two issues with managing sub-locks:
292 * - sub-locks are concurrently canceled, and
294 * - sub-locks are shared with other top-locks.
296 * To manage cancellation, top-lock acquires a hold on a sublock
297 * (lov_sublock_adopt()) when the latter is inserted into
298 * lov_lock::lls_sub[]. This hold is released (lov_sublock_release())
299 * when top-lock is going into CLS_CACHED state or destroyed. Hold
300 * prevents sub-lock from cancellation.
302 * Sub-lock sharing means, among other things, that top-lock that is
303 * in the process of creation (i.e., not yet inserted into lock list)
304 * is already accessible to other threads once at least one of its
305 * sub-locks is created, see lov_lock_sub_init().
307 * Sub-lock can be in one of the following states:
309 * - doesn't exist, lov_lock::lls_sub[]::sub_lock == NULL. Such
310 * sub-lock was either never created (top-lock is in CLS_NEW
311 * state), or it was created, then canceled, then destroyed
312 * (lov_lock_unlink() cleared sub-lock pointer in the top-lock).
314 * - sub-lock exists and is on
315 * hold. (lov_lock::lls_sub[]::sub_flags & LSF_HELD). This is a
316 * normal state of a sub-lock in CLS_HELD and CLS_CACHED states
319 * - sub-lock exists, but is not held by the top-lock. This
320 * happens after top-lock released a hold on sub-locks before
321 * going into cache (lov_lock_unuse()).
323 * \todo To support wide-striping, array has to be replaced with a set
324 * of queues to avoid scanning.
326 struct lov_lock_sub *lls_sub;
328 * Original description with which lock was enqueued.
330 struct cl_lock_descr lls_orig;
334 struct cl_page_slice lps_cl;
342 struct lovsub_device {
343 struct cl_device acid_cl;
344 struct lov_device *acid_super;
346 struct cl_device *acid_next;
349 struct lovsub_object {
350 struct cl_object_header lso_header;
351 struct cl_object lso_cl;
352 struct lov_object *lso_super;
357 * A link between a top-lock and a sub-lock. Separate data-structure is
358 * necessary, because top-locks and sub-locks are in M:N relationship.
360 * \todo This can be optimized for a (by far) most frequent case of a single
361 * top-lock per sub-lock.
363 struct lov_lock_link {
364 struct lov_lock *lll_super;
365 /** An index within parent lock. */
368 * A linkage into per sub-lock list of all corresponding top-locks,
369 * hanging off lovsub_lock::lss_parents.
375 * Lock state at lovsub layer.
378 struct cl_lock_slice lss_cl;
380 * List of top-locks that have given sub-lock as their part. Protected
381 * by cl_lock::cll_guard mutex.
383 cfs_list_t lss_parents;
385 * Top-lock that initiated current operation on this sub-lock. This is
386 * only set during top-to-bottom lock operations like enqueue, and is
387 * used to optimize state change notification. Protected by
388 * cl_lock::cll_guard mutex.
390 * \see lovsub_lock_state_one().
392 struct cl_lock *lss_active;
396 * Describe the environment settings for sublocks.
398 struct lov_sublock_env {
399 const struct lu_env *lse_env;
400 struct cl_io *lse_io;
401 struct lov_io_sub *lse_sub;
405 struct cl_page_slice lsb_cl;
409 struct lov_thread_info {
410 struct cl_object_conf lti_stripe_conf;
411 struct lu_fid lti_fid;
412 struct cl_lock_descr lti_ldescr;
413 struct ost_lvb lti_lvb;
414 struct cl_2queue lti_cl2q;
415 union lov_layout_state lti_state;
416 struct cl_lock_closure lti_closure;
417 cfs_waitlink_t lti_waiter;
421 * State that lov_io maintains for every sub-io.
426 * sub-io for a stripe. Ideally sub-io's can be stopped and resumed
427 * independently, with lov acting as a scheduler to maximize overall
430 struct cl_io *sub_io;
432 * Linkage into a list (hanging off lov_io::lis_active) of all
433 * sub-io's active for the current IO iteration.
435 cfs_list_t sub_linkage;
437 * true, iff cl_io_init() was successfully executed against
438 * lov_io_sub::sub_io.
440 int sub_io_initialized;
442 * True, iff lov_io_sub::sub_io and lov_io_sub::sub_env weren't
443 * allocated, but borrowed from a per-device emergency pool.
447 * environment, in which sub-io executes.
449 struct lu_env *sub_env;
451 * environment's refcheck.
462 * IO state private for LOV.
466 struct cl_io_slice lis_cl;
468 * Pointer to the object slice. This is a duplicate of
469 * lov_io::lis_cl::cis_object.
471 struct lov_object *lis_object;
473 * Original end-of-io position for this IO, set by the upper layer as
474 * cl_io::u::ci_rw::pos + cl_io::u::ci_rw::count. lov remembers this,
475 * changes pos and count to fit IO into a single stripe and uses saved
476 * value to determine when IO iterations have to stop.
478 * This is used only for CIT_READ and CIT_WRITE io's.
480 loff_t lis_io_endpos;
483 * starting position within a file, for the current io loop iteration
484 * (stripe), used by ci_io_loop().
488 * end position with in a file, for the current stripe io. This is
489 * exclusive (i.e., next offset after last byte affected by io).
494 int lis_stripe_count;
495 int lis_active_subios;
498 * the index of ls_single_subio in ls_subios array
500 int lis_single_subio_index;
501 struct cl_io lis_single_subio;
504 * size of ls_subios array, actually the highest stripe #
507 struct lov_io_sub *lis_subs;
509 * List of active sub-io's.
511 cfs_list_t lis_active;
516 struct lov_sublock_env ls_subenv;
520 * State of transfer for lov.
523 struct cl_req_slice lr_cl;
527 * State of transfer for lovsub.
530 struct cl_req_slice lsrq_cl;
533 extern struct lu_device_type lov_device_type;
534 extern struct lu_device_type lovsub_device_type;
536 extern struct lu_context_key lov_key;
537 extern struct lu_context_key lov_session_key;
539 extern cfs_mem_cache_t *lov_page_kmem;
540 extern cfs_mem_cache_t *lov_lock_kmem;
541 extern cfs_mem_cache_t *lov_object_kmem;
542 extern cfs_mem_cache_t *lov_thread_kmem;
543 extern cfs_mem_cache_t *lov_session_kmem;
544 extern cfs_mem_cache_t *lov_req_kmem;
546 extern cfs_mem_cache_t *lovsub_page_kmem;
547 extern cfs_mem_cache_t *lovsub_lock_kmem;
548 extern cfs_mem_cache_t *lovsub_object_kmem;
549 extern cfs_mem_cache_t *lovsub_req_kmem;
551 extern cfs_mem_cache_t *lov_lock_link_kmem;
553 int lov_object_init (const struct lu_env *env, struct lu_object *obj,
554 const struct lu_object_conf *conf);
555 int lovsub_object_init (const struct lu_env *env, struct lu_object *obj,
556 const struct lu_object_conf *conf);
557 int lov_lock_init (const struct lu_env *env, struct cl_object *obj,
558 struct cl_lock *lock, const struct cl_io *io);
559 int lov_io_init (const struct lu_env *env, struct cl_object *obj,
561 int lovsub_lock_init (const struct lu_env *env, struct cl_object *obj,
562 struct cl_lock *lock, const struct cl_io *io);
564 int lov_lock_init_raid0 (const struct lu_env *env, struct cl_object *obj,
565 struct cl_lock *lock, const struct cl_io *io);
566 int lov_io_init_raid0 (const struct lu_env *env, struct cl_object *obj,
568 int lov_io_init_empty (const struct lu_env *env, struct cl_object *obj,
570 void lov_lock_unlink (const struct lu_env *env, struct lov_lock_link *link,
571 struct lovsub_lock *sub);
573 struct lov_io_sub *lov_sub_get(const struct lu_env *env, struct lov_io *lio,
575 void lov_sub_put (struct lov_io_sub *sub);
576 int lov_sublock_modify (const struct lu_env *env, struct lov_lock *lov,
577 struct lovsub_lock *sublock,
578 const struct cl_lock_descr *d, int idx);
581 struct cl_page *lov_page_init (const struct lu_env *env, struct cl_object *ob,
582 struct cl_page *page, cfs_page_t *vmpage);
583 struct cl_page *lovsub_page_init(const struct lu_env *env, struct cl_object *ob,
584 struct cl_page *page, cfs_page_t *vmpage);
586 struct cl_page *lov_page_init_empty(const struct lu_env *env,
587 struct cl_object *obj,
588 struct cl_page *page, cfs_page_t *vmpage);
589 struct cl_page *lov_page_init_raid0(const struct lu_env *env,
590 struct cl_object *obj,
591 struct cl_page *page, cfs_page_t *vmpage);
592 struct lu_object *lov_object_alloc (const struct lu_env *env,
593 const struct lu_object_header *hdr,
594 struct lu_device *dev);
595 struct lu_object *lovsub_object_alloc(const struct lu_env *env,
596 const struct lu_object_header *hdr,
597 struct lu_device *dev);
599 struct lov_lock_link *lov_lock_link_find(const struct lu_env *env,
600 struct lov_lock *lck,
601 struct lovsub_lock *sub);
602 struct lov_io_sub *lov_page_subio (const struct lu_env *env,
604 const struct cl_page_slice *slice);
607 #define lov_foreach_target(lov, var) \
608 for (var = 0; var < lov_targets_nr(lov); ++var)
610 /*****************************************************************************
618 static inline struct lov_session *lov_env_session(const struct lu_env *env)
620 struct lov_session *ses;
622 ses = lu_context_key_get(env->le_ses, &lov_session_key);
623 LASSERT(ses != NULL);
627 static inline struct lov_io *lov_env_io(const struct lu_env *env)
629 return &lov_env_session(env)->ls_io;
632 static inline int lov_is_object(const struct lu_object *obj)
634 return obj->lo_dev->ld_type == &lov_device_type;
637 static inline int lovsub_is_object(const struct lu_object *obj)
639 return obj->lo_dev->ld_type == &lovsub_device_type;
642 static inline struct lu_device *lov2lu_dev(struct lov_device *lov)
644 return &lov->ld_cl.cd_lu_dev;
647 static inline struct lov_device *lu2lov_dev(const struct lu_device *d)
649 LINVRNT(d->ld_type == &lov_device_type);
650 return container_of0(d, struct lov_device, ld_cl.cd_lu_dev);
653 static inline struct cl_device *lovsub2cl_dev(struct lovsub_device *lovsub)
655 return &lovsub->acid_cl;
658 static inline struct lu_device *lovsub2lu_dev(struct lovsub_device *lovsub)
660 return &lovsub2cl_dev(lovsub)->cd_lu_dev;
663 static inline struct lovsub_device *lu2lovsub_dev(const struct lu_device *d)
665 LINVRNT(d->ld_type == &lovsub_device_type);
666 return container_of0(d, struct lovsub_device, acid_cl.cd_lu_dev);
669 static inline struct lovsub_device *cl2lovsub_dev(const struct cl_device *d)
671 LINVRNT(d->cd_lu_dev.ld_type == &lovsub_device_type);
672 return container_of0(d, struct lovsub_device, acid_cl);
675 static inline struct lu_object *lov2lu(struct lov_object *lov)
677 return &lov->lo_cl.co_lu;
680 static inline struct cl_object *lov2cl(struct lov_object *lov)
685 static inline struct lov_object *lu2lov(const struct lu_object *obj)
687 LINVRNT(lov_is_object(obj));
688 return container_of0(obj, struct lov_object, lo_cl.co_lu);
691 static inline struct lov_object *cl2lov(const struct cl_object *obj)
693 LINVRNT(lov_is_object(&obj->co_lu));
694 return container_of0(obj, struct lov_object, lo_cl);
697 static inline struct lu_object *lovsub2lu(struct lovsub_object *los)
699 return &los->lso_cl.co_lu;
702 static inline struct cl_object *lovsub2cl(struct lovsub_object *los)
707 static inline struct lovsub_object *cl2lovsub(const struct cl_object *obj)
709 LINVRNT(lovsub_is_object(&obj->co_lu));
710 return container_of0(obj, struct lovsub_object, lso_cl);
713 static inline struct lovsub_object *lu2lovsub(const struct lu_object *obj)
715 LINVRNT(lovsub_is_object(obj));
716 return container_of0(obj, struct lovsub_object, lso_cl.co_lu);
719 static inline struct lovsub_lock *
720 cl2lovsub_lock(const struct cl_lock_slice *slice)
722 LINVRNT(lovsub_is_object(&slice->cls_obj->co_lu));
723 return container_of(slice, struct lovsub_lock, lss_cl);
726 static inline struct lovsub_lock *cl2sub_lock(const struct cl_lock *lock)
728 const struct cl_lock_slice *slice;
730 slice = cl_lock_at(lock, &lovsub_device_type);
731 LASSERT(slice != NULL);
732 return cl2lovsub_lock(slice);
735 static inline struct lov_lock *cl2lov_lock(const struct cl_lock_slice *slice)
737 LINVRNT(lov_is_object(&slice->cls_obj->co_lu));
738 return container_of(slice, struct lov_lock, lls_cl);
741 static inline struct lov_page *cl2lov_page(const struct cl_page_slice *slice)
743 LINVRNT(lov_is_object(&slice->cpl_obj->co_lu));
744 return container_of0(slice, struct lov_page, lps_cl);
747 static inline struct lov_req *cl2lov_req(const struct cl_req_slice *slice)
749 return container_of0(slice, struct lov_req, lr_cl);
752 static inline struct lovsub_page *
753 cl2lovsub_page(const struct cl_page_slice *slice)
755 LINVRNT(lovsub_is_object(&slice->cpl_obj->co_lu));
756 return container_of0(slice, struct lovsub_page, lsb_cl);
759 static inline struct lovsub_req *cl2lovsub_req(const struct cl_req_slice *slice)
761 return container_of0(slice, struct lovsub_req, lsrq_cl);
764 static inline struct cl_page *lov_sub_page(const struct cl_page_slice *slice)
766 return slice->cpl_page->cp_child;
769 static inline struct lov_io *cl2lov_io(const struct lu_env *env,
770 const struct cl_io_slice *ios)
774 lio = container_of(ios, struct lov_io, lis_cl);
775 LASSERT(lio == lov_env_io(env));
779 static inline int lov_targets_nr(const struct lov_device *lov)
781 return lov->ld_lov->desc.ld_tgt_count;
784 static inline struct lov_thread_info *lov_env_info(const struct lu_env *env)
786 struct lov_thread_info *info;
788 info = lu_context_key_get(&env->le_ctx, &lov_key);
789 LASSERT(info != NULL);
793 static inline struct lov_layout_raid0 *lov_r0(struct lov_object *lov)
795 struct lov_layout_raid0 *raid0;
797 LASSERT(lov->lo_type == LLT_RAID0);
798 raid0 = &lov->u.raid0;
799 LASSERT(raid0->lo_lsm->lsm_wire.lw_magic == LOV_MAGIC ||
800 raid0->lo_lsm->lsm_wire.lw_magic == LOV_MAGIC_V3);