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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
49 #include <libcfs/libcfs.h>
51 #include <cl_object.h>
52 #include "lov_internal.h"
55 * Logical object volume layer. This layer implements data striping (raid0).
57 * At the lov layer top-entity (object, page, lock, io) is connected to one or
58 * more sub-entities: top-object, representing a file is connected to a set of
59 * sub-objects, each representing a stripe, file-level top-lock is connected
60 * to a set of per-stripe sub-locks, top-page is connected to a (single)
61 * sub-page, and a top-level IO is connected to a set of (potentially
62 * concurrent) sub-IO's.
64 * Sub-object, sub-page, and sub-io have well-defined top-object and top-page
65 * respectively, while a single sub-lock can be part of multiple top-locks.
67 * Reference counting models are different for different types of entities:
69 * - top-object keeps a reference to its sub-objects, and destroys them
70 * when it is destroyed.
72 * - top-page keeps a reference to its sub-page, and destroys it when it
75 * - sub-lock keep a reference to its top-locks. Top-lock keeps a
76 * reference (and a hold, see cl_lock_hold()) on its sub-locks when it
77 * actively using them (that is, in cl_lock_state::CLS_QUEUING,
78 * cl_lock_state::CLS_ENQUEUED, cl_lock_state::CLS_HELD states). When
79 * moving into cl_lock_state::CLS_CACHED state, top-lock releases a
80 * hold. From this moment top-lock has only a 'weak' reference to its
81 * sub-locks. This reference is protected by top-lock
82 * cl_lock::cll_guard, and will be automatically cleared by the sub-lock
83 * when the latter is destroyed. When a sub-lock is canceled, a
84 * reference to it is removed from the top-lock array, and top-lock is
85 * moved into CLS_NEW state. It is guaranteed that all sub-locks exist
86 * while their top-lock is in CLS_HELD or CLS_CACHED states.
88 * - IO's are not reference counted.
90 * To implement a connection between top and sub entities, lov layer is split
91 * into two pieces: lov ("upper half"), and lovsub ("bottom half"), both
92 * implementing full set of cl-interfaces. For example, top-object has vvp and
93 * lov layers, and it's sub-object has lovsub and osc layers. lovsub layer is
94 * used to track child-parent relationship.
100 struct lovsub_object;
103 enum lov_device_flags {
104 LOV_DEV_INITIALIZED = 1 << 0
112 * Resources that are used in memory-cleaning path, and whose allocation
113 * cannot fail even when memory is tight. They are preallocated in sufficient
114 * quantities in lov_device::ld_emerg[], and access to them is serialized
115 * lov_device::ld_mutex.
117 struct lov_device_emerg {
119 * Page list used to submit IO when memory is in pressure.
121 struct cl_page_list emrg_page_list;
123 * sub-io's shared by all threads accessing this device when memory is
124 * too low to allocate sub-io's dynamically.
126 struct cl_io emrg_subio;
128 * Environments used by sub-io's in
129 * lov_device_emerg::emrg_subio.
131 struct lu_env *emrg_env;
133 * Refchecks for lov_device_emerg::emrg_env.
142 * XXX Locking of lov-private data is missing.
144 struct cl_device ld_cl;
145 struct lov_obd *ld_lov;
146 /** size of lov_device::ld_target[] array */
148 struct lovsub_device **ld_target;
151 /** Emergency resources used in memory-cleansing paths. */
152 struct lov_device_emerg **ld_emrg;
154 * Serializes access to lov_device::ld_emrg in low-memory
157 struct mutex ld_mutex;
163 enum lov_layout_type {
164 LLT_EMPTY, /** empty file without body (mknod + truncate) */
165 LLT_RAID0, /** striped file */
166 LLT_RELEASED, /** file with no objects (data in HSM) */
170 static inline char *llt2str(enum lov_layout_type llt)
187 * lov-specific file state.
189 * lov object has particular layout type, determining how top-object is built
190 * on top of sub-objects. Layout type can change dynamically. When this
191 * happens, lov_object::lo_type_guard semaphore is taken in exclusive mode,
192 * all state pertaining to the old layout type is destroyed, and new state is
193 * constructed. All object methods take said semaphore in the shared mode,
194 * providing serialization against transition between layout types.
196 * To avoid multiple `if' or `switch' statements, selecting behavior for the
197 * current layout type, object methods perform double-dispatch, invoking
198 * function corresponding to the current layout type.
201 struct cl_object lo_cl;
203 * Serializes object operations with transitions between layout types.
205 * This semaphore is taken in shared mode by all object methods, and
206 * is taken in exclusive mode when object type is changed.
208 * \see lov_object::lo_type
210 struct rw_semaphore lo_type_guard;
212 * Type of an object. Protected by lov_object::lo_type_guard.
214 enum lov_layout_type lo_type;
216 * True if layout is invalid. This bit is cleared when layout lock
219 bool lo_layout_invalid;
221 * How many IOs are on going on this object. Layout can be changed
222 * only if there is no active IO.
224 atomic_t lo_active_ios;
226 * Waitq - wait for no one else is using lo_lsm
228 wait_queue_head_t lo_waitq;
230 * Layout metadata. NULL if empty layout.
232 struct lov_stripe_md *lo_lsm;
234 union lov_layout_state {
235 struct lov_layout_raid0 {
238 * When this is true, lov_object::lo_attr contains
239 * valid up to date attributes for a top-level
240 * object. This field is reset to 0 when attributes of
241 * any sub-object change.
245 * Array of sub-objects. Allocated when top-object is
246 * created (lov_init_raid0()).
248 * Top-object is a strict master of its sub-objects:
249 * it is created before them, and outlives its
250 * children (this later is necessary so that basic
251 * functions like cl_object_top() always
252 * work). Top-object keeps a reference on every
255 * When top-object is destroyed (lov_delete_raid0())
256 * it releases its reference to a sub-object and waits
257 * until the latter is finally destroyed.
259 struct lovsub_object **lo_sub;
263 spinlock_t lo_sub_lock;
265 * Cached object attribute, built from sub-object
268 struct cl_attr lo_attr;
270 struct lov_layout_state_empty {
272 struct lov_layout_state_released {
276 * Thread that acquired lov_object::lo_type_guard in an exclusive
279 struct task_struct *lo_owner;
283 * Flags that top-lock can set on each of its sub-locks.
286 /** Top-lock acquired a hold (cl_lock_hold()) on a sub-lock. */
291 * State lov_lock keeps for each sub-lock.
293 struct lov_lock_sub {
294 /** sub-lock itself */
295 struct lovsub_lock *sub_lock;
296 /** An array of per-sub-lock flags, taken from enum lov_sub_flags */
299 struct cl_lock_descr sub_descr;
300 struct cl_lock_descr sub_got;
304 * lov-specific lock state.
307 struct cl_lock_slice lls_cl;
308 /** Number of sub-locks in this lock */
311 * Number of existing sub-locks.
313 unsigned lls_nr_filled;
315 * Set when sub-lock was canceled, while top-lock was being
318 unsigned int lls_cancel_race:1,
321 * An array of sub-locks
323 * There are two issues with managing sub-locks:
325 * - sub-locks are concurrently canceled, and
327 * - sub-locks are shared with other top-locks.
329 * To manage cancellation, top-lock acquires a hold on a sublock
330 * (lov_sublock_adopt()) when the latter is inserted into
331 * lov_lock::lls_sub[]. This hold is released (lov_sublock_release())
332 * when top-lock is going into CLS_CACHED state or destroyed. Hold
333 * prevents sub-lock from cancellation.
335 * Sub-lock sharing means, among other things, that top-lock that is
336 * in the process of creation (i.e., not yet inserted into lock list)
337 * is already accessible to other threads once at least one of its
338 * sub-locks is created, see lov_lock_sub_init().
340 * Sub-lock can be in one of the following states:
342 * - doesn't exist, lov_lock::lls_sub[]::sub_lock == NULL. Such
343 * sub-lock was either never created (top-lock is in CLS_NEW
344 * state), or it was created, then canceled, then destroyed
345 * (lov_lock_unlink() cleared sub-lock pointer in the top-lock).
347 * - sub-lock exists and is on
348 * hold. (lov_lock::lls_sub[]::sub_flags & LSF_HELD). This is a
349 * normal state of a sub-lock in CLS_HELD and CLS_CACHED states
352 * - sub-lock exists, but is not held by the top-lock. This
353 * happens after top-lock released a hold on sub-locks before
354 * going into cache (lov_lock_unuse()).
356 * \todo To support wide-striping, array has to be replaced with a set
357 * of queues to avoid scanning.
359 struct lov_lock_sub *lls_sub;
361 * Original description with which lock was enqueued.
363 struct cl_lock_descr lls_orig;
367 struct cl_page_slice lps_cl;
368 unsigned int lps_stripe; /* stripe index */
375 struct lovsub_device {
376 struct cl_device acid_cl;
377 struct lov_device *acid_super;
379 struct cl_device *acid_next;
382 struct lovsub_object {
383 struct cl_object_header lso_header;
384 struct cl_object lso_cl;
385 struct lov_object *lso_super;
390 * A link between a top-lock and a sub-lock. Separate data-structure is
391 * necessary, because top-locks and sub-locks are in M:N relationship.
393 * \todo This can be optimized for a (by far) most frequent case of a single
394 * top-lock per sub-lock.
396 struct lov_lock_link {
397 struct lov_lock *lll_super;
398 /** An index within parent lock. */
401 * A linkage into per sub-lock list of all corresponding top-locks,
402 * hanging off lovsub_lock::lss_parents.
404 struct list_head lll_list;
408 * Lock state at lovsub layer.
411 struct cl_lock_slice lss_cl;
413 * List of top-locks that have given sub-lock as their part. Protected
414 * by cl_lock::cll_guard mutex.
416 struct list_head lss_parents;
418 * Top-lock that initiated current operation on this sub-lock. This is
419 * only set during top-to-bottom lock operations like enqueue, and is
420 * used to optimize state change notification. Protected by
421 * cl_lock::cll_guard mutex.
423 * \see lovsub_lock_state_one().
425 struct cl_lock *lss_active;
429 * Describe the environment settings for sublocks.
431 struct lov_sublock_env {
432 const struct lu_env *lse_env;
433 struct cl_io *lse_io;
434 struct lov_io_sub *lse_sub;
438 struct cl_page_slice lsb_cl;
442 struct lov_thread_info {
443 struct cl_object_conf lti_stripe_conf;
444 struct lu_fid lti_fid;
445 struct cl_lock_descr lti_ldescr;
446 struct ost_lvb lti_lvb;
447 struct cl_2queue lti_cl2q;
448 struct cl_page_list lti_plist;
449 struct cl_lock_closure lti_closure;
450 wait_queue_t lti_waiter;
451 struct cl_attr lti_attr;
455 * State that lov_io maintains for every sub-io.
460 * sub-io for a stripe. Ideally sub-io's can be stopped and resumed
461 * independently, with lov acting as a scheduler to maximize overall
464 struct cl_io *sub_io;
466 * Linkage into a list (hanging off lov_io::lis_active) of all
467 * sub-io's active for the current IO iteration.
469 struct list_head sub_linkage;
471 * true, iff cl_io_init() was successfully executed against
472 * lov_io_sub::sub_io.
474 int sub_io_initialized;
476 * True, iff lov_io_sub::sub_io and lov_io_sub::sub_env weren't
477 * allocated, but borrowed from a per-device emergency pool.
481 * environment, in which sub-io executes.
483 struct lu_env *sub_env;
485 * environment's refcheck.
496 * IO state private for LOV.
500 struct cl_io_slice lis_cl;
502 * Pointer to the object slice. This is a duplicate of
503 * lov_io::lis_cl::cis_object.
505 struct lov_object *lis_object;
507 * Original end-of-io position for this IO, set by the upper layer as
508 * cl_io::u::ci_rw::pos + cl_io::u::ci_rw::count. lov remembers this,
509 * changes pos and count to fit IO into a single stripe and uses saved
510 * value to determine when IO iterations have to stop.
512 * This is used only for CIT_READ and CIT_WRITE io's.
514 loff_t lis_io_endpos;
517 * starting position within a file, for the current io loop iteration
518 * (stripe), used by ci_io_loop().
522 * end position with in a file, for the current stripe io. This is
523 * exclusive (i.e., next offset after last byte affected by io).
528 int lis_stripe_count;
529 int lis_active_subios;
532 * the index of ls_single_subio in ls_subios array
534 int lis_single_subio_index;
535 struct cl_io lis_single_subio;
538 * size of ls_subios array, actually the highest stripe #
541 struct lov_io_sub *lis_subs;
543 * List of active sub-io's.
545 struct list_head lis_active;
550 struct lov_sublock_env ls_subenv;
554 * State of transfer for lov.
557 struct cl_req_slice lr_cl;
561 * State of transfer for lovsub.
564 struct cl_req_slice lsrq_cl;
567 extern struct lu_device_type lov_device_type;
568 extern struct lu_device_type lovsub_device_type;
570 extern struct lu_context_key lov_key;
571 extern struct lu_context_key lov_session_key;
573 extern struct kmem_cache *lov_lock_kmem;
574 extern struct kmem_cache *lov_object_kmem;
575 extern struct kmem_cache *lov_thread_kmem;
576 extern struct kmem_cache *lov_session_kmem;
577 extern struct kmem_cache *lov_req_kmem;
579 extern struct kmem_cache *lovsub_lock_kmem;
580 extern struct kmem_cache *lovsub_object_kmem;
581 extern struct kmem_cache *lovsub_req_kmem;
583 extern struct kmem_cache *lov_lock_link_kmem;
585 int lov_object_init (const struct lu_env *env, struct lu_object *obj,
586 const struct lu_object_conf *conf);
587 int lovsub_object_init (const struct lu_env *env, struct lu_object *obj,
588 const struct lu_object_conf *conf);
589 int lov_lock_init (const struct lu_env *env, struct cl_object *obj,
590 struct cl_lock *lock, const struct cl_io *io);
591 int lov_io_init (const struct lu_env *env, struct cl_object *obj,
593 int lovsub_lock_init (const struct lu_env *env, struct cl_object *obj,
594 struct cl_lock *lock, const struct cl_io *io);
596 int lov_lock_init_raid0 (const struct lu_env *env, struct cl_object *obj,
597 struct cl_lock *lock, const struct cl_io *io);
598 int lov_lock_init_empty (const struct lu_env *env, struct cl_object *obj,
599 struct cl_lock *lock, const struct cl_io *io);
600 int lov_io_init_raid0 (const struct lu_env *env, struct cl_object *obj,
602 int lov_io_init_empty (const struct lu_env *env, struct cl_object *obj,
604 int lov_io_init_released(const struct lu_env *env, struct cl_object *obj,
606 void lov_lock_unlink (const struct lu_env *env, struct lov_lock_link *link,
607 struct lovsub_lock *sub);
609 struct lov_io_sub *lov_sub_get(const struct lu_env *env, struct lov_io *lio,
611 void lov_sub_put (struct lov_io_sub *sub);
612 int lov_sublock_modify (const struct lu_env *env, struct lov_lock *lov,
613 struct lovsub_lock *sublock,
614 const struct cl_lock_descr *d, int idx);
617 int lov_page_init (const struct lu_env *env, struct cl_object *ob,
618 struct cl_page *page, pgoff_t index);
619 int lovsub_page_init (const struct lu_env *env, struct cl_object *ob,
620 struct cl_page *page, pgoff_t index);
621 int lov_page_init_empty (const struct lu_env *env, struct cl_object *obj,
622 struct cl_page *page, pgoff_t index);
623 int lov_page_init_raid0 (const struct lu_env *env, struct cl_object *obj,
624 struct cl_page *page, pgoff_t index);
625 struct lu_object *lov_object_alloc (const struct lu_env *env,
626 const struct lu_object_header *hdr,
627 struct lu_device *dev);
628 struct lu_object *lovsub_object_alloc(const struct lu_env *env,
629 const struct lu_object_header *hdr,
630 struct lu_device *dev);
632 struct lov_lock_link *lov_lock_link_find(const struct lu_env *env,
633 struct lov_lock *lck,
634 struct lovsub_lock *sub);
635 struct lov_io_sub *lov_page_subio (const struct lu_env *env,
637 const struct cl_page_slice *slice);
639 struct lov_stripe_md *lov_lsm_addref(struct lov_object *lov);
640 int lov_page_stripe(const struct cl_page *page);
642 #define lov_foreach_target(lov, var) \
643 for (var = 0; var < lov_targets_nr(lov); ++var)
645 /*****************************************************************************
653 static inline struct lov_session *lov_env_session(const struct lu_env *env)
655 struct lov_session *ses;
657 ses = lu_context_key_get(env->le_ses, &lov_session_key);
658 LASSERT(ses != NULL);
662 static inline struct lov_io *lov_env_io(const struct lu_env *env)
664 return &lov_env_session(env)->ls_io;
667 static inline int lov_is_object(const struct lu_object *obj)
669 return obj->lo_dev->ld_type == &lov_device_type;
672 static inline int lovsub_is_object(const struct lu_object *obj)
674 return obj->lo_dev->ld_type == &lovsub_device_type;
677 static inline struct lu_device *lov2lu_dev(struct lov_device *lov)
679 return &lov->ld_cl.cd_lu_dev;
682 static inline struct lov_device *lu2lov_dev(const struct lu_device *d)
684 LINVRNT(d->ld_type == &lov_device_type);
685 return container_of0(d, struct lov_device, ld_cl.cd_lu_dev);
688 static inline struct cl_device *lovsub2cl_dev(struct lovsub_device *lovsub)
690 return &lovsub->acid_cl;
693 static inline struct lu_device *lovsub2lu_dev(struct lovsub_device *lovsub)
695 return &lovsub2cl_dev(lovsub)->cd_lu_dev;
698 static inline struct lovsub_device *lu2lovsub_dev(const struct lu_device *d)
700 LINVRNT(d->ld_type == &lovsub_device_type);
701 return container_of0(d, struct lovsub_device, acid_cl.cd_lu_dev);
704 static inline struct lovsub_device *cl2lovsub_dev(const struct cl_device *d)
706 LINVRNT(d->cd_lu_dev.ld_type == &lovsub_device_type);
707 return container_of0(d, struct lovsub_device, acid_cl);
710 static inline struct lu_object *lov2lu(struct lov_object *lov)
712 return &lov->lo_cl.co_lu;
715 static inline struct cl_object *lov2cl(struct lov_object *lov)
720 static inline struct lov_object *lu2lov(const struct lu_object *obj)
722 LINVRNT(lov_is_object(obj));
723 return container_of0(obj, struct lov_object, lo_cl.co_lu);
726 static inline struct lov_object *cl2lov(const struct cl_object *obj)
728 LINVRNT(lov_is_object(&obj->co_lu));
729 return container_of0(obj, struct lov_object, lo_cl);
732 static inline struct lu_object *lovsub2lu(struct lovsub_object *los)
734 return &los->lso_cl.co_lu;
737 static inline struct cl_object *lovsub2cl(struct lovsub_object *los)
742 static inline struct lovsub_object *cl2lovsub(const struct cl_object *obj)
744 LINVRNT(lovsub_is_object(&obj->co_lu));
745 return container_of0(obj, struct lovsub_object, lso_cl);
748 static inline struct lovsub_object *lu2lovsub(const struct lu_object *obj)
750 LINVRNT(lovsub_is_object(obj));
751 return container_of0(obj, struct lovsub_object, lso_cl.co_lu);
754 static inline struct lovsub_lock *
755 cl2lovsub_lock(const struct cl_lock_slice *slice)
757 LINVRNT(lovsub_is_object(&slice->cls_obj->co_lu));
758 return container_of(slice, struct lovsub_lock, lss_cl);
761 static inline struct lovsub_lock *cl2sub_lock(const struct cl_lock *lock)
763 const struct cl_lock_slice *slice;
765 slice = cl_lock_at(lock, &lovsub_device_type);
766 LASSERT(slice != NULL);
767 return cl2lovsub_lock(slice);
770 static inline struct lov_lock *cl2lov_lock(const struct cl_lock_slice *slice)
772 LINVRNT(lov_is_object(&slice->cls_obj->co_lu));
773 return container_of(slice, struct lov_lock, lls_cl);
776 static inline struct lov_page *cl2lov_page(const struct cl_page_slice *slice)
778 LINVRNT(lov_is_object(&slice->cpl_obj->co_lu));
779 return container_of0(slice, struct lov_page, lps_cl);
782 static inline struct lov_req *cl2lov_req(const struct cl_req_slice *slice)
784 return container_of0(slice, struct lov_req, lr_cl);
787 static inline struct lovsub_page *
788 cl2lovsub_page(const struct cl_page_slice *slice)
790 LINVRNT(lovsub_is_object(&slice->cpl_obj->co_lu));
791 return container_of0(slice, struct lovsub_page, lsb_cl);
794 static inline struct lovsub_req *cl2lovsub_req(const struct cl_req_slice *slice)
796 return container_of0(slice, struct lovsub_req, lsrq_cl);
799 static inline struct lov_io *cl2lov_io(const struct lu_env *env,
800 const struct cl_io_slice *ios)
804 lio = container_of(ios, struct lov_io, lis_cl);
805 LASSERT(lio == lov_env_io(env));
809 static inline int lov_targets_nr(const struct lov_device *lov)
811 return lov->ld_lov->desc.ld_tgt_count;
814 static inline struct lov_thread_info *lov_env_info(const struct lu_env *env)
816 struct lov_thread_info *info;
818 info = lu_context_key_get(&env->le_ctx, &lov_key);
819 LASSERT(info != NULL);
823 static inline struct lov_layout_raid0 *lov_r0(struct lov_object *lov)
825 LASSERT(lov->lo_type == LLT_RAID0);
826 LASSERT(lov->lo_lsm->lsm_wire.lw_magic == LOV_MAGIC ||
827 lov->lo_lsm->lsm_wire.lw_magic == LOV_MAGIC_V3);
828 return &lov->u.raid0;