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40 * Internal interfaces of LOV layer.
42 * Author: Nikita Danilov <nikita.danilov@sun.com>
43 * Author: Jinshan Xiong <jinshan.xiong@intel.com>
46 #ifndef LOV_CL_INTERNAL_H
47 #define LOV_CL_INTERNAL_H
50 # include <libcfs/libcfs.h>
52 # include <liblustre.h>
56 #include <cl_object.h>
57 #include "lov_internal.h"
60 * Logical object volume layer. This layer implements data striping (raid0).
62 * At the lov layer top-entity (object, page, lock, io) is connected to one or
63 * more sub-entities: top-object, representing a file is connected to a set of
64 * sub-objects, each representing a stripe, file-level top-lock is connected
65 * to a set of per-stripe sub-locks, top-page is connected to a (single)
66 * sub-page, and a top-level IO is connected to a set of (potentially
67 * concurrent) sub-IO's.
69 * Sub-object, sub-page, and sub-io have well-defined top-object and top-page
70 * respectively, while a single sub-lock can be part of multiple top-locks.
72 * Reference counting models are different for different types of entities:
74 * - top-object keeps a reference to its sub-objects, and destroys them
75 * when it is destroyed.
77 * - top-page keeps a reference to its sub-page, and destroys it when it
80 * - sub-lock keep a reference to its top-locks. Top-lock keeps a
81 * reference (and a hold, see cl_lock_hold()) on its sub-locks when it
82 * actively using them (that is, in cl_lock_state::CLS_QUEUING,
83 * cl_lock_state::CLS_ENQUEUED, cl_lock_state::CLS_HELD states). When
84 * moving into cl_lock_state::CLS_CACHED state, top-lock releases a
85 * hold. From this moment top-lock has only a 'weak' reference to its
86 * sub-locks. This reference is protected by top-lock
87 * cl_lock::cll_guard, and will be automatically cleared by the sub-lock
88 * when the latter is destroyed. When a sub-lock is canceled, a
89 * reference to it is removed from the top-lock array, and top-lock is
90 * moved into CLS_NEW state. It is guaranteed that all sub-locks exist
91 * while their top-lock is in CLS_HELD or CLS_CACHED states.
93 * - IO's are not reference counted.
95 * To implement a connection between top and sub entities, lov layer is split
96 * into two pieces: lov ("upper half"), and lovsub ("bottom half"), both
97 * implementing full set of cl-interfaces. For example, top-object has vvp and
98 * lov layers, and it's sub-object has lovsub and osc layers. lovsub layer is
99 * used to track child-parent relationship.
104 struct lovsub_device;
105 struct lovsub_object;
108 enum lov_device_flags {
109 LOV_DEV_INITIALIZED = 1 << 0
117 * Resources that are used in memory-cleaning path, and whose allocation
118 * cannot fail even when memory is tight. They are preallocated in sufficient
119 * quantities in lov_device::ld_emerg[], and access to them is serialized
120 * lov_device::ld_mutex.
122 struct lov_device_emerg {
124 * Page list used to submit IO when memory is in pressure.
126 struct cl_page_list emrg_page_list;
128 * sub-io's shared by all threads accessing this device when memory is
129 * too low to allocate sub-io's dynamically.
131 struct cl_io emrg_subio;
133 * Environments used by sub-io's in
134 * lov_device_emerg::emrg_subio.
136 struct lu_env *emrg_env;
138 * Refchecks for lov_device_emerg::emrg_env.
147 * XXX Locking of lov-private data is missing.
149 struct cl_device ld_cl;
150 struct lov_obd *ld_lov;
151 /** size of lov_device::ld_target[] array */
153 struct lovsub_device **ld_target;
156 /** Emergency resources used in memory-cleansing paths. */
157 struct lov_device_emerg **ld_emrg;
159 * Serializes access to lov_device::ld_emrg in low-memory
162 struct mutex ld_mutex;
168 enum lov_layout_type {
169 LLT_EMPTY, /** empty file without body (mknod + truncate) */
170 LLT_RAID0, /** striped file */
171 LLT_RELEASED, /** file with no objects (data in HSM) */
175 static inline char *llt2str(enum lov_layout_type llt)
192 * lov-specific file state.
194 * lov object has particular layout type, determining how top-object is built
195 * on top of sub-objects. Layout type can change dynamically. When this
196 * happens, lov_object::lo_type_guard semaphore is taken in exclusive mode,
197 * all state pertaining to the old layout type is destroyed, and new state is
198 * constructed. All object methods take said semaphore in the shared mode,
199 * providing serialization against transition between layout types.
201 * To avoid multiple `if' or `switch' statements, selecting behavior for the
202 * current layout type, object methods perform double-dispatch, invoking
203 * function corresponding to the current layout type.
206 struct cl_object lo_cl;
208 * Serializes object operations with transitions between layout types.
210 * This semaphore is taken in shared mode by all object methods, and
211 * is taken in exclusive mode when object type is changed.
213 * \see lov_object::lo_type
215 struct rw_semaphore lo_type_guard;
217 * Type of an object. Protected by lov_object::lo_type_guard.
219 enum lov_layout_type lo_type;
221 * True if layout is invalid. This bit is cleared when layout lock
224 bool lo_layout_invalid;
226 * How many IOs are on going on this object. Layout can be changed
227 * only if there is no active IO.
229 cfs_atomic_t lo_active_ios;
231 * Waitq - wait for no one else is using lo_lsm
233 wait_queue_head_t lo_waitq;
235 * Layout metadata. NULL if empty layout.
237 struct lov_stripe_md *lo_lsm;
239 union lov_layout_state {
240 struct lov_layout_raid0 {
243 * When this is true, lov_object::lo_attr contains
244 * valid up to date attributes for a top-level
245 * object. This field is reset to 0 when attributes of
246 * any sub-object change.
250 * Array of sub-objects. Allocated when top-object is
251 * created (lov_init_raid0()).
253 * Top-object is a strict master of its sub-objects:
254 * it is created before them, and outlives its
255 * children (this later is necessary so that basic
256 * functions like cl_object_top() always
257 * work). Top-object keeps a reference on every
260 * When top-object is destroyed (lov_delete_raid0())
261 * it releases its reference to a sub-object and waits
262 * until the latter is finally destroyed.
264 struct lovsub_object **lo_sub;
268 spinlock_t lo_sub_lock;
270 * Cached object attribute, built from sub-object
273 struct cl_attr lo_attr;
275 struct lov_layout_state_empty {
277 struct lov_layout_state_released {
281 * Thread that acquired lov_object::lo_type_guard in an exclusive
284 struct task_struct *lo_owner;
288 * Flags that top-lock can set on each of its sub-locks.
291 /** Top-lock acquired a hold (cl_lock_hold()) on a sub-lock. */
296 * State lov_lock keeps for each sub-lock.
298 struct lov_lock_sub {
299 /** sub-lock itself */
300 struct lovsub_lock *sub_lock;
301 /** An array of per-sub-lock flags, taken from enum lov_sub_flags */
304 struct cl_lock_descr sub_descr;
305 struct cl_lock_descr sub_got;
309 * lov-specific lock state.
312 struct cl_lock_slice lls_cl;
313 /** Number of sub-locks in this lock */
316 * Number of existing sub-locks.
318 unsigned lls_nr_filled;
320 * Set when sub-lock was canceled, while top-lock was being
323 unsigned int lls_cancel_race:1,
326 * An array of sub-locks
328 * There are two issues with managing sub-locks:
330 * - sub-locks are concurrently canceled, and
332 * - sub-locks are shared with other top-locks.
334 * To manage cancellation, top-lock acquires a hold on a sublock
335 * (lov_sublock_adopt()) when the latter is inserted into
336 * lov_lock::lls_sub[]. This hold is released (lov_sublock_release())
337 * when top-lock is going into CLS_CACHED state or destroyed. Hold
338 * prevents sub-lock from cancellation.
340 * Sub-lock sharing means, among other things, that top-lock that is
341 * in the process of creation (i.e., not yet inserted into lock list)
342 * is already accessible to other threads once at least one of its
343 * sub-locks is created, see lov_lock_sub_init().
345 * Sub-lock can be in one of the following states:
347 * - doesn't exist, lov_lock::lls_sub[]::sub_lock == NULL. Such
348 * sub-lock was either never created (top-lock is in CLS_NEW
349 * state), or it was created, then canceled, then destroyed
350 * (lov_lock_unlink() cleared sub-lock pointer in the top-lock).
352 * - sub-lock exists and is on
353 * hold. (lov_lock::lls_sub[]::sub_flags & LSF_HELD). This is a
354 * normal state of a sub-lock in CLS_HELD and CLS_CACHED states
357 * - sub-lock exists, but is not held by the top-lock. This
358 * happens after top-lock released a hold on sub-locks before
359 * going into cache (lov_lock_unuse()).
361 * \todo To support wide-striping, array has to be replaced with a set
362 * of queues to avoid scanning.
364 struct lov_lock_sub *lls_sub;
366 * Original description with which lock was enqueued.
368 struct cl_lock_descr lls_orig;
372 struct cl_page_slice lps_cl;
380 struct lovsub_device {
381 struct cl_device acid_cl;
382 struct lov_device *acid_super;
384 struct cl_device *acid_next;
387 struct lovsub_object {
388 struct cl_object_header lso_header;
389 struct cl_object lso_cl;
390 struct lov_object *lso_super;
395 * A link between a top-lock and a sub-lock. Separate data-structure is
396 * necessary, because top-locks and sub-locks are in M:N relationship.
398 * \todo This can be optimized for a (by far) most frequent case of a single
399 * top-lock per sub-lock.
401 struct lov_lock_link {
402 struct lov_lock *lll_super;
403 /** An index within parent lock. */
406 * A linkage into per sub-lock list of all corresponding top-locks,
407 * hanging off lovsub_lock::lss_parents.
413 * Lock state at lovsub layer.
416 struct cl_lock_slice lss_cl;
418 * List of top-locks that have given sub-lock as their part. Protected
419 * by cl_lock::cll_guard mutex.
421 cfs_list_t lss_parents;
423 * Top-lock that initiated current operation on this sub-lock. This is
424 * only set during top-to-bottom lock operations like enqueue, and is
425 * used to optimize state change notification. Protected by
426 * cl_lock::cll_guard mutex.
428 * \see lovsub_lock_state_one().
430 struct cl_lock *lss_active;
434 * Describe the environment settings for sublocks.
436 struct lov_sublock_env {
437 const struct lu_env *lse_env;
438 struct cl_io *lse_io;
439 struct lov_io_sub *lse_sub;
443 struct cl_page_slice lsb_cl;
447 struct lov_thread_info {
448 struct cl_object_conf lti_stripe_conf;
449 struct lu_fid lti_fid;
450 struct cl_lock_descr lti_ldescr;
451 struct ost_lvb lti_lvb;
452 struct cl_2queue lti_cl2q;
453 struct cl_lock_closure lti_closure;
454 wait_queue_t lti_waiter;
458 * State that lov_io maintains for every sub-io.
463 * sub-io for a stripe. Ideally sub-io's can be stopped and resumed
464 * independently, with lov acting as a scheduler to maximize overall
467 struct cl_io *sub_io;
469 * Linkage into a list (hanging off lov_io::lis_active) of all
470 * sub-io's active for the current IO iteration.
472 cfs_list_t sub_linkage;
474 * true, iff cl_io_init() was successfully executed against
475 * lov_io_sub::sub_io.
477 int sub_io_initialized;
479 * True, iff lov_io_sub::sub_io and lov_io_sub::sub_env weren't
480 * allocated, but borrowed from a per-device emergency pool.
484 * environment, in which sub-io executes.
486 struct lu_env *sub_env;
488 * environment's refcheck.
499 * IO state private for LOV.
503 struct cl_io_slice lis_cl;
505 * Pointer to the object slice. This is a duplicate of
506 * lov_io::lis_cl::cis_object.
508 struct lov_object *lis_object;
510 * Original end-of-io position for this IO, set by the upper layer as
511 * cl_io::u::ci_rw::pos + cl_io::u::ci_rw::count. lov remembers this,
512 * changes pos and count to fit IO into a single stripe and uses saved
513 * value to determine when IO iterations have to stop.
515 * This is used only for CIT_READ and CIT_WRITE io's.
517 loff_t lis_io_endpos;
520 * starting position within a file, for the current io loop iteration
521 * (stripe), used by ci_io_loop().
525 * end position with in a file, for the current stripe io. This is
526 * exclusive (i.e., next offset after last byte affected by io).
531 int lis_stripe_count;
532 int lis_active_subios;
535 * the index of ls_single_subio in ls_subios array
537 int lis_single_subio_index;
538 struct cl_io lis_single_subio;
541 * size of ls_subios array, actually the highest stripe #
544 struct lov_io_sub *lis_subs;
546 * List of active sub-io's.
548 cfs_list_t lis_active;
553 struct lov_sublock_env ls_subenv;
557 * State of transfer for lov.
560 struct cl_req_slice lr_cl;
564 * State of transfer for lovsub.
567 struct cl_req_slice lsrq_cl;
570 extern struct lu_device_type lov_device_type;
571 extern struct lu_device_type lovsub_device_type;
573 extern struct lu_context_key lov_key;
574 extern struct lu_context_key lov_session_key;
576 extern struct kmem_cache *lov_lock_kmem;
577 extern struct kmem_cache *lov_object_kmem;
578 extern struct kmem_cache *lov_thread_kmem;
579 extern struct kmem_cache *lov_session_kmem;
580 extern struct kmem_cache *lov_req_kmem;
582 extern struct kmem_cache *lovsub_lock_kmem;
583 extern struct kmem_cache *lovsub_object_kmem;
584 extern struct kmem_cache *lovsub_req_kmem;
586 extern struct kmem_cache *lov_lock_link_kmem;
588 int lov_object_init (const struct lu_env *env, struct lu_object *obj,
589 const struct lu_object_conf *conf);
590 int lovsub_object_init (const struct lu_env *env, struct lu_object *obj,
591 const struct lu_object_conf *conf);
592 int lov_lock_init (const struct lu_env *env, struct cl_object *obj,
593 struct cl_lock *lock, const struct cl_io *io);
594 int lov_io_init (const struct lu_env *env, struct cl_object *obj,
596 int lovsub_lock_init (const struct lu_env *env, struct cl_object *obj,
597 struct cl_lock *lock, const struct cl_io *io);
599 int lov_lock_init_raid0 (const struct lu_env *env, struct cl_object *obj,
600 struct cl_lock *lock, const struct cl_io *io);
601 int lov_lock_init_empty (const struct lu_env *env, struct cl_object *obj,
602 struct cl_lock *lock, const struct cl_io *io);
603 int lov_io_init_raid0 (const struct lu_env *env, struct cl_object *obj,
605 int lov_io_init_empty (const struct lu_env *env, struct cl_object *obj,
607 int lov_io_init_released(const struct lu_env *env, struct cl_object *obj,
609 void lov_lock_unlink (const struct lu_env *env, struct lov_lock_link *link,
610 struct lovsub_lock *sub);
612 struct lov_io_sub *lov_sub_get(const struct lu_env *env, struct lov_io *lio,
614 void lov_sub_put (struct lov_io_sub *sub);
615 int lov_sublock_modify (const struct lu_env *env, struct lov_lock *lov,
616 struct lovsub_lock *sublock,
617 const struct cl_lock_descr *d, int idx);
620 int lov_page_init (const struct lu_env *env, struct cl_object *ob,
621 struct cl_page *page, struct page *vmpage);
622 int lovsub_page_init (const struct lu_env *env, struct cl_object *ob,
623 struct cl_page *page, struct page *vmpage);
625 int lov_page_init_empty (const struct lu_env *env,
626 struct cl_object *obj,
627 struct cl_page *page, struct page *vmpage);
628 int lov_page_init_raid0 (const struct lu_env *env,
629 struct cl_object *obj,
630 struct cl_page *page, struct page *vmpage);
631 struct lu_object *lov_object_alloc (const struct lu_env *env,
632 const struct lu_object_header *hdr,
633 struct lu_device *dev);
634 struct lu_object *lovsub_object_alloc(const struct lu_env *env,
635 const struct lu_object_header *hdr,
636 struct lu_device *dev);
638 struct lov_lock_link *lov_lock_link_find(const struct lu_env *env,
639 struct lov_lock *lck,
640 struct lovsub_lock *sub);
641 struct lov_io_sub *lov_page_subio (const struct lu_env *env,
643 const struct cl_page_slice *slice);
645 void lov_lsm_decref(struct lov_object *lov, struct lov_stripe_md *lsm);
646 struct lov_stripe_md *lov_lsm_addref(struct lov_object *lov);
648 #define lov_foreach_target(lov, var) \
649 for (var = 0; var < lov_targets_nr(lov); ++var)
651 /*****************************************************************************
659 static inline struct lov_session *lov_env_session(const struct lu_env *env)
661 struct lov_session *ses;
663 ses = lu_context_key_get(env->le_ses, &lov_session_key);
664 LASSERT(ses != NULL);
668 static inline struct lov_io *lov_env_io(const struct lu_env *env)
670 return &lov_env_session(env)->ls_io;
673 static inline int lov_is_object(const struct lu_object *obj)
675 return obj->lo_dev->ld_type == &lov_device_type;
678 static inline int lovsub_is_object(const struct lu_object *obj)
680 return obj->lo_dev->ld_type == &lovsub_device_type;
683 static inline struct lu_device *lov2lu_dev(struct lov_device *lov)
685 return &lov->ld_cl.cd_lu_dev;
688 static inline struct lov_device *lu2lov_dev(const struct lu_device *d)
690 LINVRNT(d->ld_type == &lov_device_type);
691 return container_of0(d, struct lov_device, ld_cl.cd_lu_dev);
694 static inline struct cl_device *lovsub2cl_dev(struct lovsub_device *lovsub)
696 return &lovsub->acid_cl;
699 static inline struct lu_device *lovsub2lu_dev(struct lovsub_device *lovsub)
701 return &lovsub2cl_dev(lovsub)->cd_lu_dev;
704 static inline struct lovsub_device *lu2lovsub_dev(const struct lu_device *d)
706 LINVRNT(d->ld_type == &lovsub_device_type);
707 return container_of0(d, struct lovsub_device, acid_cl.cd_lu_dev);
710 static inline struct lovsub_device *cl2lovsub_dev(const struct cl_device *d)
712 LINVRNT(d->cd_lu_dev.ld_type == &lovsub_device_type);
713 return container_of0(d, struct lovsub_device, acid_cl);
716 static inline struct lu_object *lov2lu(struct lov_object *lov)
718 return &lov->lo_cl.co_lu;
721 static inline struct cl_object *lov2cl(struct lov_object *lov)
726 static inline struct lov_object *lu2lov(const struct lu_object *obj)
728 LINVRNT(lov_is_object(obj));
729 return container_of0(obj, struct lov_object, lo_cl.co_lu);
732 static inline struct lov_object *cl2lov(const struct cl_object *obj)
734 LINVRNT(lov_is_object(&obj->co_lu));
735 return container_of0(obj, struct lov_object, lo_cl);
738 static inline struct lu_object *lovsub2lu(struct lovsub_object *los)
740 return &los->lso_cl.co_lu;
743 static inline struct cl_object *lovsub2cl(struct lovsub_object *los)
748 static inline struct lovsub_object *cl2lovsub(const struct cl_object *obj)
750 LINVRNT(lovsub_is_object(&obj->co_lu));
751 return container_of0(obj, struct lovsub_object, lso_cl);
754 static inline struct lovsub_object *lu2lovsub(const struct lu_object *obj)
756 LINVRNT(lovsub_is_object(obj));
757 return container_of0(obj, struct lovsub_object, lso_cl.co_lu);
760 static inline struct lovsub_lock *
761 cl2lovsub_lock(const struct cl_lock_slice *slice)
763 LINVRNT(lovsub_is_object(&slice->cls_obj->co_lu));
764 return container_of(slice, struct lovsub_lock, lss_cl);
767 static inline struct lovsub_lock *cl2sub_lock(const struct cl_lock *lock)
769 const struct cl_lock_slice *slice;
771 slice = cl_lock_at(lock, &lovsub_device_type);
772 LASSERT(slice != NULL);
773 return cl2lovsub_lock(slice);
776 static inline struct lov_lock *cl2lov_lock(const struct cl_lock_slice *slice)
778 LINVRNT(lov_is_object(&slice->cls_obj->co_lu));
779 return container_of(slice, struct lov_lock, lls_cl);
782 static inline struct lov_page *cl2lov_page(const struct cl_page_slice *slice)
784 LINVRNT(lov_is_object(&slice->cpl_obj->co_lu));
785 return container_of0(slice, struct lov_page, lps_cl);
788 static inline struct lov_req *cl2lov_req(const struct cl_req_slice *slice)
790 return container_of0(slice, struct lov_req, lr_cl);
793 static inline struct lovsub_page *
794 cl2lovsub_page(const struct cl_page_slice *slice)
796 LINVRNT(lovsub_is_object(&slice->cpl_obj->co_lu));
797 return container_of0(slice, struct lovsub_page, lsb_cl);
800 static inline struct lovsub_req *cl2lovsub_req(const struct cl_req_slice *slice)
802 return container_of0(slice, struct lovsub_req, lsrq_cl);
805 static inline struct cl_page *lov_sub_page(const struct cl_page_slice *slice)
807 return slice->cpl_page->cp_child;
810 static inline struct lov_io *cl2lov_io(const struct lu_env *env,
811 const struct cl_io_slice *ios)
815 lio = container_of(ios, struct lov_io, lis_cl);
816 LASSERT(lio == lov_env_io(env));
820 static inline int lov_targets_nr(const struct lov_device *lov)
822 return lov->ld_lov->desc.ld_tgt_count;
825 static inline struct lov_thread_info *lov_env_info(const struct lu_env *env)
827 struct lov_thread_info *info;
829 info = lu_context_key_get(&env->le_ctx, &lov_key);
830 LASSERT(info != NULL);
834 static inline struct lov_layout_raid0 *lov_r0(struct lov_object *lov)
836 LASSERT(lov->lo_type == LLT_RAID0);
837 LASSERT(lov->lo_lsm->lsm_wire.lw_magic == LOV_MAGIC ||
838 lov->lo_lsm->lsm_wire.lw_magic == LOV_MAGIC_V3);
839 return &lov->u.raid0;