4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
30 * Copyright (c) 2011, 2012, Intel Corporation.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
37 #ifndef __LUSTRE_LU_OBJECT_H
38 #define __LUSTRE_LU_OBJECT_H
41 #include "../../include/linux/libcfs/libcfs.h"
42 #include "lustre/lustre_idl.h"
50 * lu_* data-types represent server-side entities shared by data and meta-data
55 * -# support for layering.
57 * Server side object is split into layers, one per device in the
58 * corresponding device stack. Individual layer is represented by struct
59 * lu_object. Compound layered object --- by struct lu_object_header. Most
60 * interface functions take lu_object as an argument and operate on the
61 * whole compound object. This decision was made due to the following
64 * - it's envisaged that lu_object will be used much more often than
67 * - we want lower (non-top) layers to be able to initiate operations
68 * on the whole object.
70 * Generic code supports layering more complex than simple stacking, e.g.,
71 * it is possible that at some layer object "spawns" multiple sub-objects
74 * -# fid-based identification.
76 * Compound object is uniquely identified by its fid. Objects are indexed
77 * by their fids (hash table is used for index).
79 * -# caching and life-cycle management.
81 * Object's life-time is controlled by reference counting. When reference
82 * count drops to 0, object is returned to cache. Cached objects still
83 * retain their identity (i.e., fid), and can be recovered from cache.
85 * Objects are kept in the global LRU list, and lu_site_purge() function
86 * can be used to reclaim given number of unused objects from the tail of
89 * -# avoiding recursion.
91 * Generic code tries to replace recursion through layers by iterations
92 * where possible. Additionally to the end of reducing stack consumption,
93 * data, when practically possible, are allocated through lu_context_key
94 * interface rather than on stack.
101 struct lu_object_header;
106 * Operations common for data and meta-data devices.
108 struct lu_device_operations {
110 * Allocate object for the given device (without lower-layer
111 * parts). This is called by lu_object_operations::loo_object_init()
112 * from the parent layer, and should setup at least lu_object::lo_dev
113 * and lu_object::lo_ops fields of resulting lu_object.
115 * Object creation protocol.
117 * Due to design goal of avoiding recursion, object creation (see
118 * lu_object_alloc()) is somewhat involved:
120 * - first, lu_device_operations::ldo_object_alloc() method of the
121 * top-level device in the stack is called. It should allocate top
122 * level object (including lu_object_header), but without any
123 * lower-layer sub-object(s).
125 * - then lu_object_alloc() sets fid in the header of newly created
128 * - then lu_object_operations::loo_object_init() is called. It has
129 * to allocate lower-layer object(s). To do this,
130 * lu_object_operations::loo_object_init() calls ldo_object_alloc()
131 * of the lower-layer device(s).
133 * - for all new objects allocated by
134 * lu_object_operations::loo_object_init() (and inserted into object
135 * stack), lu_object_operations::loo_object_init() is called again
136 * repeatedly, until no new objects are created.
138 * \post ergo(!IS_ERR(result), result->lo_dev == d &&
139 * result->lo_ops != NULL);
141 struct lu_object *(*ldo_object_alloc)(const struct lu_env *env,
142 const struct lu_object_header *h,
143 struct lu_device *d);
145 * process config specific for device.
147 int (*ldo_process_config)(const struct lu_env *env,
148 struct lu_device *, struct lustre_cfg *);
149 int (*ldo_recovery_complete)(const struct lu_env *,
153 * initialize local objects for device. this method called after layer has
154 * been initialized (after LCFG_SETUP stage) and before it starts serving
158 int (*ldo_prepare)(const struct lu_env *,
159 struct lu_device *parent,
160 struct lu_device *dev);
165 * For lu_object_conf flags
168 /* This is a new object to be allocated, or the file
169 * corresponding to the object does not exists. */
170 LOC_F_NEW = 0x00000001,
174 * Object configuration, describing particulars of object being created. On
175 * server this is not used, as server objects are full identified by fid. On
176 * client configuration contains struct lustre_md.
178 struct lu_object_conf {
180 * Some hints for obj find and alloc.
182 loc_flags_t loc_flags;
186 * Type of "printer" function used by lu_object_operations::loo_object_print()
189 * Printer function is needed to provide some flexibility in (semi-)debugging
190 * output: possible implementations: printk, CDEBUG, sysfs/seq_file
192 typedef int (*lu_printer_t)(const struct lu_env *env,
193 void *cookie, const char *format, ...)
197 * Operations specific for particular lu_object.
199 struct lu_object_operations {
202 * Allocate lower-layer parts of the object by calling
203 * lu_device_operations::ldo_object_alloc() of the corresponding
206 * This method is called once for each object inserted into object
207 * stack. It's responsibility of this method to insert lower-layer
208 * object(s) it create into appropriate places of object stack.
210 int (*loo_object_init)(const struct lu_env *env,
212 const struct lu_object_conf *conf);
214 * Called (in top-to-bottom order) during object allocation after all
215 * layers were allocated and initialized. Can be used to perform
216 * initialization depending on lower layers.
218 int (*loo_object_start)(const struct lu_env *env,
219 struct lu_object *o);
221 * Called before lu_object_operations::loo_object_free() to signal
222 * that object is being destroyed. Dual to
223 * lu_object_operations::loo_object_init().
225 void (*loo_object_delete)(const struct lu_env *env,
226 struct lu_object *o);
228 * Dual to lu_device_operations::ldo_object_alloc(). Called when
229 * object is removed from memory.
231 void (*loo_object_free)(const struct lu_env *env,
232 struct lu_object *o);
234 * Called when last active reference to the object is released (and
235 * object returns to the cache). This method is optional.
237 void (*loo_object_release)(const struct lu_env *env,
238 struct lu_object *o);
240 * Optional debugging helper. Print given object.
242 int (*loo_object_print)(const struct lu_env *env, void *cookie,
243 lu_printer_t p, const struct lu_object *o);
245 * Optional debugging method. Returns true iff method is internally
248 int (*loo_object_invariant)(const struct lu_object *o);
254 struct lu_device_type;
257 * Device: a layer in the server side abstraction stacking.
261 * reference count. This is incremented, in particular, on each object
262 * created at this layer.
264 * \todo XXX which means that atomic_t is probably too small.
268 * Pointer to device type. Never modified once set.
270 struct lu_device_type *ld_type;
272 * Operation vector for this device.
274 const struct lu_device_operations *ld_ops;
276 * Stack this device belongs to.
278 struct lu_site *ld_site;
280 /** \todo XXX: temporary back pointer into obd. */
281 struct obd_device *ld_obd;
283 * A list of references to this object, for debugging.
285 struct lu_ref ld_reference;
287 * Link the device to the site.
289 struct list_head ld_linkage;
292 struct lu_device_type_operations;
295 * Tag bits for device type. They are used to distinguish certain groups of
299 /** this is meta-data device */
300 LU_DEVICE_MD = (1 << 0),
301 /** this is data device */
302 LU_DEVICE_DT = (1 << 1),
303 /** data device in the client stack */
304 LU_DEVICE_CL = (1 << 2)
310 struct lu_device_type {
312 * Tag bits. Taken from enum lu_device_tag. Never modified once set.
316 * Name of this class. Unique system-wide. Never modified once set.
320 * Operations for this type.
322 const struct lu_device_type_operations *ldt_ops;
324 * \todo XXX: temporary pointer to associated obd_type.
326 struct obd_type *ldt_obd_type;
328 * \todo XXX: temporary: context tags used by obd_*() calls.
332 * Number of existing device type instances.
334 unsigned ldt_device_nr;
336 * Linkage into a global list of all device types.
338 * \see lu_device_types.
340 struct list_head ldt_linkage;
344 * Operations on a device type.
346 struct lu_device_type_operations {
348 * Allocate new device.
350 struct lu_device *(*ldto_device_alloc)(const struct lu_env *env,
351 struct lu_device_type *t,
352 struct lustre_cfg *lcfg);
354 * Free device. Dual to
355 * lu_device_type_operations::ldto_device_alloc(). Returns pointer to
356 * the next device in the stack.
358 struct lu_device *(*ldto_device_free)(const struct lu_env *,
362 * Initialize the devices after allocation
364 int (*ldto_device_init)(const struct lu_env *env,
365 struct lu_device *, const char *,
368 * Finalize device. Dual to
369 * lu_device_type_operations::ldto_device_init(). Returns pointer to
370 * the next device in the stack.
372 struct lu_device *(*ldto_device_fini)(const struct lu_env *env,
375 * Initialize device type. This is called on module load.
377 int (*ldto_init)(struct lu_device_type *t);
379 * Finalize device type. Dual to
380 * lu_device_type_operations::ldto_init(). Called on module unload.
382 void (*ldto_fini)(struct lu_device_type *t);
384 * Called when the first device is created.
386 void (*ldto_start)(struct lu_device_type *t);
388 * Called when number of devices drops to 0.
390 void (*ldto_stop)(struct lu_device_type *t);
393 static inline int lu_device_is_md(const struct lu_device *d)
395 return ergo(d != NULL, d->ld_type->ldt_tags & LU_DEVICE_MD);
399 * Common object attributes.
404 /** modification time in seconds since Epoch */
406 /** access time in seconds since Epoch */
408 /** change time in seconds since Epoch */
410 /** 512-byte blocks allocated to object */
412 /** permission bits and file type */
420 /** number of persistent references to this object */
422 /** blk bits of the object*/
424 /** blk size of the object*/
436 /** Bit-mask of valid attributes */
450 LA_BLKSIZE = 1 << 12,
451 LA_KILL_SUID = 1 << 13,
452 LA_KILL_SGID = 1 << 14,
456 * Layer in the layered object.
460 * Header for this object.
462 struct lu_object_header *lo_header;
464 * Device for this layer.
466 struct lu_device *lo_dev;
468 * Operations for this object.
470 const struct lu_object_operations *lo_ops;
472 * Linkage into list of all layers.
474 struct list_head lo_linkage;
476 * Link to the device, for debugging.
478 struct lu_ref_link lo_dev_ref;
481 enum lu_object_header_flags {
483 * Don't keep this object in cache. Object will be destroyed as soon
484 * as last reference to it is released. This flag cannot be cleared
487 LU_OBJECT_HEARD_BANSHEE = 0,
489 * Mark this object has already been taken out of cache.
491 LU_OBJECT_UNHASHED = 1
494 enum lu_object_header_attr {
495 LOHA_EXISTS = 1 << 0,
496 LOHA_REMOTE = 1 << 1,
498 * UNIX file type is stored in S_IFMT bits.
500 LOHA_FT_START = 001 << 12, /**< S_IFIFO */
501 LOHA_FT_END = 017 << 12, /**< S_IFMT */
505 * "Compound" object, consisting of multiple layers.
507 * Compound object with given fid is unique with given lu_site.
509 * Note, that object does *not* necessary correspond to the real object in the
510 * persistent storage: object is an anchor for locking and method calling, so
511 * it is created for things like not-yet-existing child created by mkdir or
512 * create calls. lu_object_operations::loo_exists() can be used to check
513 * whether object is backed by persistent storage entity.
515 struct lu_object_header {
517 * Fid, uniquely identifying this object.
519 struct lu_fid loh_fid;
521 * Object flags from enum lu_object_header_flags. Set and checked
524 unsigned long loh_flags;
526 * Object reference count. Protected by lu_site::ls_guard.
530 * Common object attributes, cached for efficiency. From enum
531 * lu_object_header_attr.
535 * Linkage into per-site hash table. Protected by lu_site::ls_guard.
537 struct hlist_node loh_hash;
539 * Linkage into per-site LRU list. Protected by lu_site::ls_guard.
541 struct list_head loh_lru;
543 * Linkage into list of layers. Never modified once set (except lately
544 * during object destruction). No locking is necessary.
546 struct list_head loh_layers;
548 * A list of references to this object, for debugging.
550 struct lu_ref loh_reference;
555 struct lu_site_bkt_data {
557 * number of object in this bucket on the lsb_lru list.
561 * LRU list, updated on each access to object. Protected by
562 * bucket lock of lu_site::ls_obj_hash.
564 * "Cold" end of LRU is lu_site::ls_lru.next. Accessed object are
565 * moved to the lu_site::ls_lru.prev (this is due to the non-existence
566 * of list_for_each_entry_safe_reverse()).
568 struct list_head lsb_lru;
570 * Wait-queue signaled when an object in this site is ultimately
571 * destroyed (lu_object_free()). It is used by lu_object_find() to
572 * wait before re-trying when object in the process of destruction is
573 * found in the hash table.
575 * \see htable_lookup().
577 wait_queue_head_t lsb_marche_funebre;
585 LU_SS_CACHE_DEATH_RACE,
587 LU_SS_LRU_LEN, /* # of objects in lsb_lru lists */
592 * lu_site is a "compartment" within which objects are unique, and LRU
593 * discipline is maintained.
595 * lu_site exists so that multiple layered stacks can co-exist in the same
598 * lu_site has the same relation to lu_device as lu_object_header to
605 struct cfs_hash *ls_obj_hash;
607 * index of bucket on hash table while purging
611 * Top-level device for this stack.
613 struct lu_device *ls_top_dev;
615 * Bottom-level device for this stack
617 struct lu_device *ls_bottom_dev;
619 * Linkage into global list of sites.
621 struct list_head ls_linkage;
623 * List for lu device for this site, protected
626 struct list_head ls_ld_linkage;
627 spinlock_t ls_ld_lock;
632 struct lprocfs_stats *ls_stats;
634 * XXX: a hack! fld has to find md_site via site, remove when possible
636 struct seq_server_site *ld_seq_site;
639 static inline struct lu_site_bkt_data *
640 lu_site_bkt_from_fid(struct lu_site *site, struct lu_fid *fid)
642 struct cfs_hash_bd bd;
644 cfs_hash_bd_get(site->ls_obj_hash, fid, &bd);
645 return cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
648 static inline struct seq_server_site *lu_site2seq(const struct lu_site *s)
650 return s->ld_seq_site;
654 * Constructors/destructors.
658 int lu_site_init (struct lu_site *s, struct lu_device *d);
659 void lu_site_fini (struct lu_site *s);
660 int lu_site_init_finish (struct lu_site *s);
661 void lu_stack_fini (const struct lu_env *env, struct lu_device *top);
662 void lu_device_get (struct lu_device *d);
663 void lu_device_put (struct lu_device *d);
664 int lu_device_init (struct lu_device *d, struct lu_device_type *t);
665 void lu_device_fini (struct lu_device *d);
666 int lu_object_header_init(struct lu_object_header *h);
667 void lu_object_header_fini(struct lu_object_header *h);
668 int lu_object_init (struct lu_object *o,
669 struct lu_object_header *h, struct lu_device *d);
670 void lu_object_fini (struct lu_object *o);
671 void lu_object_add_top (struct lu_object_header *h, struct lu_object *o);
672 void lu_object_add (struct lu_object *before, struct lu_object *o);
675 * Helpers to initialize and finalize device types.
678 int lu_device_type_init(struct lu_device_type *ldt);
679 void lu_device_type_fini(struct lu_device_type *ldt);
680 void lu_types_stop(void);
685 * Caching and reference counting.
690 * Acquire additional reference to the given object. This function is used to
691 * attain additional reference. To acquire initial reference use
694 static inline void lu_object_get(struct lu_object *o)
696 LASSERT(atomic_read(&o->lo_header->loh_ref) > 0);
697 atomic_inc(&o->lo_header->loh_ref);
701 * Return true of object will not be cached after last reference to it is
704 static inline int lu_object_is_dying(const struct lu_object_header *h)
706 return test_bit(LU_OBJECT_HEARD_BANSHEE, &h->loh_flags);
709 void lu_object_put(const struct lu_env *env, struct lu_object *o);
710 void lu_object_unhash(const struct lu_env *env, struct lu_object *o);
712 int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr);
714 void lu_site_print(const struct lu_env *env, struct lu_site *s, void *cookie,
715 lu_printer_t printer);
716 struct lu_object *lu_object_find_at(const struct lu_env *env,
717 struct lu_device *dev,
718 const struct lu_fid *f,
719 const struct lu_object_conf *conf);
720 struct lu_object *lu_object_find_slice(const struct lu_env *env,
721 struct lu_device *dev,
722 const struct lu_fid *f,
723 const struct lu_object_conf *conf);
732 * First (topmost) sub-object of given compound object
734 static inline struct lu_object *lu_object_top(struct lu_object_header *h)
736 LASSERT(!list_empty(&h->loh_layers));
737 return container_of0(h->loh_layers.next, struct lu_object, lo_linkage);
741 * Next sub-object in the layering
743 static inline struct lu_object *lu_object_next(const struct lu_object *o)
745 return container_of0(o->lo_linkage.next, struct lu_object, lo_linkage);
749 * Pointer to the fid of this object.
751 static inline const struct lu_fid *lu_object_fid(const struct lu_object *o)
753 return &o->lo_header->loh_fid;
757 * return device operations vector for this object
759 static const inline struct lu_device_operations *
760 lu_object_ops(const struct lu_object *o)
762 return o->lo_dev->ld_ops;
766 * Given a compound object, find its slice, corresponding to the device type
769 struct lu_object *lu_object_locate(struct lu_object_header *h,
770 const struct lu_device_type *dtype);
773 * Printer function emitting messages through libcfs_debug_msg().
775 int lu_cdebug_printer(const struct lu_env *env,
776 void *cookie, const char *format, ...);
779 * Print object description followed by a user-supplied message.
781 #define LU_OBJECT_DEBUG(mask, env, object, format, ...) \
783 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
785 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
786 lu_object_print(env, &msgdata, lu_cdebug_printer, object);\
787 CDEBUG(mask, format, ## __VA_ARGS__); \
792 * Print short object description followed by a user-supplied message.
794 #define LU_OBJECT_HEADER(mask, env, object, format, ...) \
796 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
798 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
799 lu_object_header_print(env, &msgdata, lu_cdebug_printer,\
800 (object)->lo_header); \
801 lu_cdebug_printer(env, &msgdata, "\n"); \
802 CDEBUG(mask, format, ## __VA_ARGS__); \
806 void lu_object_print (const struct lu_env *env, void *cookie,
807 lu_printer_t printer, const struct lu_object *o);
808 void lu_object_header_print(const struct lu_env *env, void *cookie,
809 lu_printer_t printer,
810 const struct lu_object_header *hdr);
813 * Check object consistency.
815 int lu_object_invariant(const struct lu_object *o);
818 * Check whether object exists, no matter on local or remote storage.
819 * Note: LOHA_EXISTS will be set once some one created the object,
820 * and it does not needs to be committed to storage.
822 #define lu_object_exists(o) ((o)->lo_header->loh_attr & LOHA_EXISTS)
825 * Check whether object on the remote storage.
827 #define lu_object_remote(o) unlikely((o)->lo_header->loh_attr & LOHA_REMOTE)
829 static inline int lu_object_assert_exists(const struct lu_object *o)
831 return lu_object_exists(o);
834 static inline int lu_object_assert_not_exists(const struct lu_object *o)
836 return !lu_object_exists(o);
840 * Attr of this object.
842 static inline __u32 lu_object_attr(const struct lu_object *o)
844 LASSERT(lu_object_exists(o) != 0);
845 return o->lo_header->loh_attr;
848 static inline void lu_object_ref_add(struct lu_object *o,
852 lu_ref_add(&o->lo_header->loh_reference, scope, source);
855 static inline void lu_object_ref_add_at(struct lu_object *o,
856 struct lu_ref_link *link,
860 lu_ref_add_at(&o->lo_header->loh_reference, link, scope, source);
863 static inline void lu_object_ref_del(struct lu_object *o,
864 const char *scope, const void *source)
866 lu_ref_del(&o->lo_header->loh_reference, scope, source);
869 static inline void lu_object_ref_del_at(struct lu_object *o,
870 struct lu_ref_link *link,
871 const char *scope, const void *source)
873 lu_ref_del_at(&o->lo_header->loh_reference, link, scope, source);
876 /** input params, should be filled out by mdt */
880 /** count in bytes */
881 unsigned int rp_count;
882 /** number of pages */
883 unsigned int rp_npages;
884 /** requested attr */
886 /** pointers to pages */
887 struct page **rp_pages;
890 enum lu_xattr_flags {
891 LU_XATTR_REPLACE = (1 << 0),
892 LU_XATTR_CREATE = (1 << 1)
900 /** For lu_context health-checks */
901 enum lu_context_state {
909 * lu_context. Execution context for lu_object methods. Currently associated
912 * All lu_object methods, except device and device type methods (called during
913 * system initialization and shutdown) are executed "within" some
914 * lu_context. This means, that pointer to some "current" lu_context is passed
915 * as an argument to all methods.
917 * All service ptlrpc threads create lu_context as part of their
918 * initialization. It is possible to create "stand-alone" context for other
919 * execution environments (like system calls).
921 * lu_object methods mainly use lu_context through lu_context_key interface
922 * that allows each layer to associate arbitrary pieces of data with each
923 * context (see pthread_key_create(3) for similar interface).
925 * On a client, lu_context is bound to a thread, see cl_env_get().
927 * \see lu_context_key
931 * lu_context is used on the client side too. Yet we don't want to
932 * allocate values of server-side keys for the client contexts and
935 * To achieve this, set of tags in introduced. Contexts and keys are
936 * marked with tags. Key value are created only for context whose set
937 * of tags has non-empty intersection with one for key. Tags are taken
938 * from enum lu_context_tag.
941 enum lu_context_state lc_state;
943 * Pointer to the home service thread. NULL for other execution
946 struct ptlrpc_thread *lc_thread;
948 * Pointer to an array with key values. Internal implementation
953 * Linkage into a list of all remembered contexts. Only
954 * `non-transient' contexts, i.e., ones created for service threads
957 struct list_head lc_remember;
959 * Version counter used to skip calls to lu_context_refill() when no
960 * keys were registered.
970 * lu_context_key interface. Similar to pthread_key.
973 enum lu_context_tag {
975 * Thread on md server
977 LCT_MD_THREAD = 1 << 0,
979 * Thread on dt server
981 LCT_DT_THREAD = 1 << 1,
983 * Context for transaction handle
985 LCT_TX_HANDLE = 1 << 2,
989 LCT_CL_THREAD = 1 << 3,
991 * A per-request session on a server, and a per-system-call session on
994 LCT_SESSION = 1 << 4,
996 * A per-request data on OSP device
998 LCT_OSP_THREAD = 1 << 5,
1002 LCT_MG_THREAD = 1 << 6,
1004 * Context for local operations
1008 * Set when at least one of keys, having values in this context has
1009 * non-NULL lu_context_key::lct_exit() method. This is used to
1010 * optimize lu_context_exit() call.
1012 LCT_HAS_EXIT = 1 << 28,
1014 * Don't add references for modules creating key values in that context.
1015 * This is only for contexts used internally by lu_object framework.
1017 LCT_NOREF = 1 << 29,
1019 * Key is being prepared for retiring, don't create new values for it.
1021 LCT_QUIESCENT = 1 << 30,
1023 * Context should be remembered.
1025 LCT_REMEMBER = 1 << 31,
1027 * Contexts usable in cache shrinker thread.
1029 LCT_SHRINKER = LCT_MD_THREAD|LCT_DT_THREAD|LCT_CL_THREAD|LCT_NOREF
1033 * Key. Represents per-context value slot.
1035 * Keys are usually registered when module owning the key is initialized, and
1036 * de-registered when module is unloaded. Once key is registered, all new
1037 * contexts with matching tags, will get key value. "Old" contexts, already
1038 * initialized at the time of key registration, can be forced to get key value
1039 * by calling lu_context_refill().
1041 * Every key value is counted in lu_context_key::lct_used and acquires a
1042 * reference on an owning module. This means, that all key values have to be
1043 * destroyed before module can be unloaded. This is usually achieved by
1044 * stopping threads started by the module, that created contexts in their
1045 * entry functions. Situation is complicated by the threads shared by multiple
1046 * modules, like ptlrpcd daemon on a client. To work around this problem,
1047 * contexts, created in such threads, are `remembered' (see
1048 * LCT_REMEMBER)---i.e., added into a global list. When module is preparing
1049 * for unloading it does the following:
1051 * - marks its keys as `quiescent' (lu_context_tag::LCT_QUIESCENT)
1052 * preventing new key values from being allocated in the new contexts,
1055 * - scans a list of remembered contexts, destroying values of module
1056 * keys, thus releasing references to the module.
1058 * This is done by lu_context_key_quiesce(). If module is re-activated
1059 * before key has been de-registered, lu_context_key_revive() call clears
1060 * `quiescent' marker.
1062 * lu_context code doesn't provide any internal synchronization for these
1063 * activities---it's assumed that startup (including threads start-up) and
1064 * shutdown are serialized by some external means.
1068 struct lu_context_key {
1070 * Set of tags for which values of this key are to be instantiated.
1074 * Value constructor. This is called when new value is created for a
1075 * context. Returns pointer to new value of error pointer.
1077 void *(*lct_init)(const struct lu_context *ctx,
1078 struct lu_context_key *key);
1080 * Value destructor. Called when context with previously allocated
1081 * value of this slot is destroyed. \a data is a value that was returned
1082 * by a matching call to lu_context_key::lct_init().
1084 void (*lct_fini)(const struct lu_context *ctx,
1085 struct lu_context_key *key, void *data);
1087 * Optional method called on lu_context_exit() for all allocated
1088 * keys. Can be used by debugging code checking that locks are
1091 void (*lct_exit)(const struct lu_context *ctx,
1092 struct lu_context_key *key, void *data);
1094 * Internal implementation detail: index within lu_context::lc_value[]
1095 * reserved for this key.
1099 * Internal implementation detail: number of values created for this
1104 * Internal implementation detail: module for this key.
1106 struct module *lct_owner;
1108 * References to this key. For debugging.
1110 struct lu_ref lct_reference;
1113 #define LU_KEY_INIT(mod, type) \
1114 static void *mod##_key_init(const struct lu_context *ctx, \
1115 struct lu_context_key *key) \
1119 CLASSERT(PAGE_CACHE_SIZE >= sizeof (*value)); \
1121 value = kzalloc(sizeof(*value), GFP_NOFS); \
1122 if (value == NULL) \
1123 value = ERR_PTR(-ENOMEM); \
1127 struct __##mod##__dummy_init {; } /* semicolon catcher */
1129 #define LU_KEY_FINI(mod, type) \
1130 static void mod##_key_fini(const struct lu_context *ctx, \
1131 struct lu_context_key *key, void *data) \
1133 type *info = data; \
1137 struct __##mod##__dummy_fini {; } /* semicolon catcher */
1139 #define LU_KEY_INIT_FINI(mod, type) \
1140 LU_KEY_INIT(mod, type); \
1141 LU_KEY_FINI(mod, type)
1143 #define LU_CONTEXT_KEY_DEFINE(mod, tags) \
1144 struct lu_context_key mod##_thread_key = { \
1146 .lct_init = mod##_key_init, \
1147 .lct_fini = mod##_key_fini \
1150 #define LU_CONTEXT_KEY_INIT(key) \
1152 (key)->lct_owner = THIS_MODULE; \
1155 int lu_context_key_register(struct lu_context_key *key);
1156 void lu_context_key_degister(struct lu_context_key *key);
1157 void *lu_context_key_get (const struct lu_context *ctx,
1158 const struct lu_context_key *key);
1159 void lu_context_key_quiesce (struct lu_context_key *key);
1160 void lu_context_key_revive (struct lu_context_key *key);
1163 * LU_KEY_INIT_GENERIC() has to be a macro to correctly determine an
1167 #define LU_KEY_INIT_GENERIC(mod) \
1168 static void mod##_key_init_generic(struct lu_context_key *k, ...) \
1170 struct lu_context_key *key = k; \
1173 va_start(args, k); \
1175 LU_CONTEXT_KEY_INIT(key); \
1176 key = va_arg(args, struct lu_context_key *); \
1177 } while (key != NULL); \
1181 #define LU_TYPE_INIT(mod, ...) \
1182 LU_KEY_INIT_GENERIC(mod) \
1183 static int mod##_type_init(struct lu_device_type *t) \
1185 mod##_key_init_generic(__VA_ARGS__, NULL); \
1186 return lu_context_key_register_many(__VA_ARGS__, NULL); \
1188 struct __##mod##_dummy_type_init {; }
1190 #define LU_TYPE_FINI(mod, ...) \
1191 static void mod##_type_fini(struct lu_device_type *t) \
1193 lu_context_key_degister_many(__VA_ARGS__, NULL); \
1195 struct __##mod##_dummy_type_fini {; }
1197 #define LU_TYPE_START(mod, ...) \
1198 static void mod##_type_start(struct lu_device_type *t) \
1200 lu_context_key_revive_many(__VA_ARGS__, NULL); \
1202 struct __##mod##_dummy_type_start {; }
1204 #define LU_TYPE_STOP(mod, ...) \
1205 static void mod##_type_stop(struct lu_device_type *t) \
1207 lu_context_key_quiesce_many(__VA_ARGS__, NULL); \
1209 struct __##mod##_dummy_type_stop {; }
1211 #define LU_TYPE_INIT_FINI(mod, ...) \
1212 LU_TYPE_INIT(mod, __VA_ARGS__); \
1213 LU_TYPE_FINI(mod, __VA_ARGS__); \
1214 LU_TYPE_START(mod, __VA_ARGS__); \
1215 LU_TYPE_STOP(mod, __VA_ARGS__)
1217 int lu_context_init (struct lu_context *ctx, __u32 tags);
1218 void lu_context_fini (struct lu_context *ctx);
1219 void lu_context_enter (struct lu_context *ctx);
1220 void lu_context_exit (struct lu_context *ctx);
1221 int lu_context_refill(struct lu_context *ctx);
1224 * Helper functions to operate on multiple keys. These are used by the default
1225 * device type operations, defined by LU_TYPE_INIT_FINI().
1228 int lu_context_key_register_many(struct lu_context_key *k, ...);
1229 void lu_context_key_degister_many(struct lu_context_key *k, ...);
1230 void lu_context_key_revive_many (struct lu_context_key *k, ...);
1231 void lu_context_key_quiesce_many (struct lu_context_key *k, ...);
1238 * "Local" context, used to store data instead of stack.
1240 struct lu_context le_ctx;
1242 * "Session" context for per-request data.
1244 struct lu_context *le_ses;
1247 int lu_env_init (struct lu_env *env, __u32 tags);
1248 void lu_env_fini (struct lu_env *env);
1249 int lu_env_refill(struct lu_env *env);
1251 /** @} lu_context */
1254 * Output site statistical counters into a buffer. Suitable for
1255 * ll_rd_*()-style functions.
1257 int lu_site_stats_print(const struct lu_site *s, struct seq_file *m);
1260 * Common name structure to be passed around for various name related methods.
1263 const char *ln_name;
1268 * Common buffer structure to be passed around for various xattr_{s,g}et()
1276 #define DLUBUF "(%p %zu)"
1277 #define PLUBUF(buf) (buf)->lb_buf, (buf)->lb_len
1279 * One-time initializers, called at obdclass module initialization, not
1284 * Initialization of global lu_* data.
1286 int lu_global_init(void);
1289 * Dual to lu_global_init().
1291 void lu_global_fini(void);
1293 struct lu_kmem_descr {
1294 struct kmem_cache **ckd_cache;
1295 const char *ckd_name;
1296 const size_t ckd_size;
1299 int lu_kmem_init(struct lu_kmem_descr *caches);
1300 void lu_kmem_fini(struct lu_kmem_descr *caches);
1303 #endif /* __LUSTRE_LU_OBJECT_H */