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14 * in the LICENSE file that accompanied this code).
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29 * This file is part of Lustre, http://www.lustre.org/
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33 #ifndef __LUSTRE_LU_OBJECT_H
34 #define __LUSTRE_LU_OBJECT_H
37 #include <linux/percpu_counter.h>
38 #include <linux/libcfs/libcfs.h>
39 #include <uapi/linux/lustre/lustre_idl.h>
47 * lu_* data-types represent server-side entities shared by data and meta-data
52 * -# support for layering.
54 * Server side object is split into layers, one per device in the
55 * corresponding device stack. Individual layer is represented by struct
56 * lu_object. Compound layered object --- by struct lu_object_header. Most
57 * interface functions take lu_object as an argument and operate on the
58 * whole compound object. This decision was made due to the following
61 * - it's envisaged that lu_object will be used much more often than
64 * - we want lower (non-top) layers to be able to initiate operations
65 * on the whole object.
67 * Generic code supports layering more complex than simple stacking, e.g.,
68 * it is possible that at some layer object "spawns" multiple sub-objects
71 * -# fid-based identification.
73 * Compound object is uniquely identified by its fid. Objects are indexed
74 * by their fids (hash table is used for index).
76 * -# caching and life-cycle management.
78 * Object's life-time is controlled by reference counting. When reference
79 * count drops to 0, object is returned to cache. Cached objects still
80 * retain their identity (i.e., fid), and can be recovered from cache.
82 * Objects are kept in the global LRU list, and lu_site_purge() function
83 * can be used to reclaim given number of unused objects from the tail of
86 * -# avoiding recursion.
88 * Generic code tries to replace recursion through layers by iterations
89 * where possible. Additionally to the end of reducing stack consumption,
90 * data, when practically possible, are allocated through lu_context_key
91 * interface rather than on stack.
98 struct lu_object_header;
103 * Operations common for data and meta-data devices.
105 struct lu_device_operations {
107 * Allocate object for the given device (without lower-layer
108 * parts). This is called by lu_object_operations::loo_object_init()
109 * from the parent layer, and should setup at least lu_object::lo_dev
110 * and lu_object::lo_ops fields of resulting lu_object.
112 * Object creation protocol.
114 * Due to design goal of avoiding recursion, object creation (see
115 * lu_object_alloc()) is somewhat involved:
117 * - first, lu_device_operations::ldo_object_alloc() method of the
118 * top-level device in the stack is called. It should allocate top
119 * level object (including lu_object_header), but without any
120 * lower-layer sub-object(s).
122 * - then lu_object_alloc() sets fid in the header of newly created
125 * - then lu_object_operations::loo_object_init() is called. It has
126 * to allocate lower-layer object(s). To do this,
127 * lu_object_operations::loo_object_init() calls ldo_object_alloc()
128 * of the lower-layer device(s).
130 * - for all new objects allocated by
131 * lu_object_operations::loo_object_init() (and inserted into object
132 * stack), lu_object_operations::loo_object_init() is called again
133 * repeatedly, until no new objects are created.
135 * \post ergo(!IS_ERR(result), result->lo_dev == d &&
136 * result->lo_ops != NULL);
138 struct lu_object *(*ldo_object_alloc)(const struct lu_env *env,
139 const struct lu_object_header *h,
140 struct lu_device *d);
142 * process config specific for device.
144 int (*ldo_process_config)(const struct lu_env *env,
145 struct lu_device *, struct lustre_cfg *);
146 int (*ldo_recovery_complete)(const struct lu_env *,
150 * initialize local objects for device. this method called after layer
151 * has been initialized (after LCFG_SETUP stage) and before it starts
152 * serving user requests.
155 int (*ldo_prepare)(const struct lu_env *,
156 struct lu_device *parent,
157 struct lu_device *dev);
162 * For lu_object_conf flags
165 /* This is a new object to be allocated, or the file
166 * corresponding to the object does not exists.
168 LOC_F_NEW = 0x00000001,
172 * Object configuration, describing particulars of object being created. On
173 * server this is not used, as server objects are full identified by fid. On
174 * client configuration contains struct lustre_md.
176 struct lu_object_conf {
178 * Some hints for obj find and alloc.
180 enum loc_flags loc_flags;
184 * Type of "printer" function used by lu_object_operations::loo_object_print()
187 * Printer function is needed to provide some flexibility in (semi-)debugging
188 * output: possible implementations: printk, CDEBUG, sysfs/seq_file
190 typedef int (*lu_printer_t)(const struct lu_env *env,
191 void *cookie, const char *format, ...)
195 * Operations specific for particular lu_object.
197 struct lu_object_operations {
199 * Allocate lower-layer parts of the object by calling
200 * lu_device_operations::ldo_object_alloc() of the corresponding
203 * This method is called once for each object inserted into object
204 * stack. It's responsibility of this method to insert lower-layer
205 * object(s) it create into appropriate places of object stack.
207 int (*loo_object_init)(const struct lu_env *env,
209 const struct lu_object_conf *conf);
211 * Called (in top-to-bottom order) during object allocation after all
212 * layers were allocated and initialized. Can be used to perform
213 * initialization depending on lower layers.
215 int (*loo_object_start)(const struct lu_env *env,
216 struct lu_object *o);
218 * Called before lu_object_operations::loo_object_free() to signal
219 * that object is being destroyed. Dual to
220 * lu_object_operations::loo_object_init().
222 void (*loo_object_delete)(const struct lu_env *env,
223 struct lu_object *o);
225 * Dual to lu_device_operations::ldo_object_alloc(). Called when
226 * object is removed from memory.
228 void (*loo_object_free)(const struct lu_env *env,
229 struct lu_object *o);
231 * Called when last active reference to the object is released (and
232 * object returns to the cache). This method is optional.
234 void (*loo_object_release)(const struct lu_env *env,
235 struct lu_object *o);
237 * Optional debugging helper. Print given object.
239 int (*loo_object_print)(const struct lu_env *env, void *cookie,
240 lu_printer_t p, const struct lu_object *o);
242 * Optional debugging method. Returns true iff method is internally
245 int (*loo_object_invariant)(const struct lu_object *o);
251 struct lu_device_type;
254 * Device: a layer in the server side abstraction stacking.
258 * reference count. This is incremented, in particular, on each object
259 * created at this layer.
261 * \todo XXX which means that atomic_t is probably too small.
265 * Pointer to device type. Never modified once set.
267 struct lu_device_type *ld_type;
269 * Operation vector for this device.
271 const struct lu_device_operations *ld_ops;
273 * Stack this device belongs to.
275 struct lu_site *ld_site;
277 /** \todo XXX: temporary back pointer into obd. */
278 struct obd_device *ld_obd;
280 * A list of references to this object, for debugging.
282 struct lu_ref ld_reference;
284 * Link the device to the site.
286 struct list_head ld_linkage;
289 struct lu_device_type_operations;
292 * Tag bits for device type. They are used to distinguish certain groups of
296 /** this is meta-data device */
297 LU_DEVICE_MD = (1 << 0),
298 /** this is data device */
299 LU_DEVICE_DT = (1 << 1),
300 /** data device in the client stack */
301 LU_DEVICE_CL = (1 << 2)
307 struct lu_device_type {
309 * Tag bits. Taken from enum lu_device_tag. Never modified once set.
313 * Name of this class. Unique system-wide. Never modified once set.
317 * Operations for this type.
319 const struct lu_device_type_operations *ldt_ops;
321 * \todo XXX: temporary pointer to associated obd_type.
323 struct obd_type *ldt_obd_type;
325 * \todo XXX: temporary: context tags used by obd_*() calls.
329 * Number of existing device type instances.
331 atomic_t ldt_device_nr;
333 * Linkage into a global list of all device types.
335 * \see lu_device_types.
337 struct list_head ldt_linkage;
341 * Operations on a device type.
343 struct lu_device_type_operations {
345 * Allocate new device.
347 struct lu_device *(*ldto_device_alloc)(const struct lu_env *env,
348 struct lu_device_type *t,
349 struct lustre_cfg *lcfg);
351 * Free device. Dual to
352 * lu_device_type_operations::ldto_device_alloc(). Returns pointer to
353 * the next device in the stack.
355 struct lu_device *(*ldto_device_free)(const struct lu_env *,
359 * Initialize the devices after allocation
361 int (*ldto_device_init)(const struct lu_env *env,
362 struct lu_device *, const char *,
365 * Finalize device. Dual to
366 * lu_device_type_operations::ldto_device_init(). Returns pointer to
367 * the next device in the stack.
369 struct lu_device *(*ldto_device_fini)(const struct lu_env *env,
372 * Initialize device type. This is called on module load.
374 int (*ldto_init)(struct lu_device_type *t);
376 * Finalize device type. Dual to
377 * lu_device_type_operations::ldto_init(). Called on module unload.
379 void (*ldto_fini)(struct lu_device_type *t);
381 * Called when the first device is created.
383 void (*ldto_start)(struct lu_device_type *t);
385 * Called when number of devices drops to 0.
387 void (*ldto_stop)(struct lu_device_type *t);
390 static inline int lu_device_is_md(const struct lu_device *d)
392 return ergo(d, d->ld_type->ldt_tags & LU_DEVICE_MD);
396 * Common object attributes.
401 /** modification time in seconds since Epoch */
403 /** access time in seconds since Epoch */
405 /** change time in seconds since Epoch */
407 /** 512-byte blocks allocated to object */
409 /** permission bits and file type */
417 /** number of persistent references to this object */
419 /** blk bits of the object*/
421 /** blk size of the object*/
433 /** Bit-mask of valid attributes */
447 LA_BLKSIZE = 1 << 12,
448 LA_KILL_SUID = 1 << 13,
449 LA_KILL_SGID = 1 << 14,
453 * Layer in the layered object.
457 * Header for this object.
459 struct lu_object_header *lo_header;
461 * Device for this layer.
463 struct lu_device *lo_dev;
465 * Operations for this object.
467 const struct lu_object_operations *lo_ops;
469 * Linkage into list of all layers.
471 struct list_head lo_linkage;
473 * Link to the device, for debugging.
475 struct lu_ref_link lo_dev_ref;
478 enum lu_object_header_flags {
480 * Don't keep this object in cache. Object will be destroyed as soon
481 * as last reference to it is released. This flag cannot be cleared
484 LU_OBJECT_HEARD_BANSHEE = 0,
486 * Mark this object has already been taken out of cache.
488 LU_OBJECT_UNHASHED = 1,
491 enum lu_object_header_attr {
492 LOHA_EXISTS = 1 << 0,
493 LOHA_REMOTE = 1 << 1,
495 * UNIX file type is stored in S_IFMT bits.
497 LOHA_FT_START = 001 << 12, /**< S_IFIFO */
498 LOHA_FT_END = 017 << 12, /**< S_IFMT */
502 * "Compound" object, consisting of multiple layers.
504 * Compound object with given fid is unique with given lu_site.
506 * Note, that object does *not* necessary correspond to the real object in the
507 * persistent storage: object is an anchor for locking and method calling, so
508 * it is created for things like not-yet-existing child created by mkdir or
509 * create calls. lu_object_operations::loo_exists() can be used to check
510 * whether object is backed by persistent storage entity.
512 struct lu_object_header {
514 * Fid, uniquely identifying this object.
516 struct lu_fid loh_fid;
518 * Object flags from enum lu_object_header_flags. Set and checked
521 unsigned long loh_flags;
523 * Object reference count. Protected by lu_site::ls_guard.
527 * Common object attributes, cached for efficiency. From enum
528 * lu_object_header_attr.
532 * Linkage into per-site hash table. Protected by lu_site::ls_guard.
534 struct hlist_node loh_hash;
536 * Linkage into per-site LRU list. Protected by lu_site::ls_guard.
538 struct list_head loh_lru;
540 * Linkage into list of layers. Never modified once set (except lately
541 * during object destruction). No locking is necessary.
543 struct list_head loh_layers;
545 * A list of references to this object, for debugging.
547 struct lu_ref loh_reference;
552 struct lu_site_bkt_data {
554 * number of object in this bucket on the lsb_lru list.
558 * LRU list, updated on each access to object. Protected by
559 * bucket lock of lu_site::ls_obj_hash.
561 * "Cold" end of LRU is lu_site::ls_lru.next. Accessed object are
562 * moved to the lu_site::ls_lru.prev (this is due to the non-existence
563 * of list_for_each_entry_safe_reverse()).
565 struct list_head lsb_lru;
567 * Wait-queue signaled when an object in this site is ultimately
568 * destroyed (lu_object_free()). It is used by lu_object_find() to
569 * wait before re-trying when object in the process of destruction is
570 * found in the hash table.
572 * \see htable_lookup().
574 wait_queue_head_t lsb_marche_funebre;
582 LU_SS_CACHE_DEATH_RACE,
588 * lu_site is a "compartment" within which objects are unique, and LRU
589 * discipline is maintained.
591 * lu_site exists so that multiple layered stacks can co-exist in the same
594 * lu_site has the same relation to lu_device as lu_object_header to
601 struct cfs_hash *ls_obj_hash;
603 * index of bucket on hash table while purging
605 unsigned int ls_purge_start;
607 * Top-level device for this stack.
609 struct lu_device *ls_top_dev;
611 * Bottom-level device for this stack
613 struct lu_device *ls_bottom_dev;
615 * Linkage into global list of sites.
617 struct list_head ls_linkage;
619 * List for lu device for this site, protected
622 struct list_head ls_ld_linkage;
623 spinlock_t ls_ld_lock;
626 * Lock to serialize site purge.
628 struct mutex ls_purge_mutex;
633 struct lprocfs_stats *ls_stats;
635 * XXX: a hack! fld has to find md_site via site, remove when possible
637 struct seq_server_site *ld_seq_site;
639 * Number of objects in lsb_lru_lists - used for shrinking
641 struct percpu_counter ls_lru_len_counter;
644 static inline struct lu_site_bkt_data *
645 lu_site_bkt_from_fid(struct lu_site *site, struct lu_fid *fid)
647 struct cfs_hash_bd bd;
649 cfs_hash_bd_get(site->ls_obj_hash, fid, &bd);
650 return cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
653 static inline struct seq_server_site *lu_site2seq(const struct lu_site *s)
655 return s->ld_seq_site;
659 * Constructors/destructors.
663 int lu_site_init(struct lu_site *s, struct lu_device *d);
664 void lu_site_fini(struct lu_site *s);
665 int lu_site_init_finish(struct lu_site *s);
666 void lu_stack_fini(const struct lu_env *env, struct lu_device *top);
667 void lu_device_get(struct lu_device *d);
668 void lu_device_put(struct lu_device *d);
669 int lu_device_init(struct lu_device *d, struct lu_device_type *t);
670 void lu_device_fini(struct lu_device *d);
671 int lu_object_header_init(struct lu_object_header *h);
672 void lu_object_header_fini(struct lu_object_header *h);
673 int lu_object_init(struct lu_object *o,
674 struct lu_object_header *h, struct lu_device *d);
675 void lu_object_fini(struct lu_object *o);
676 void lu_object_add_top(struct lu_object_header *h, struct lu_object *o);
677 void lu_object_add(struct lu_object *before, struct lu_object *o);
680 * Helpers to initialize and finalize device types.
683 int lu_device_type_init(struct lu_device_type *ldt);
684 void lu_device_type_fini(struct lu_device_type *ldt);
689 * Caching and reference counting.
694 * Acquire additional reference to the given object. This function is used to
695 * attain additional reference. To acquire initial reference use
698 static inline void lu_object_get(struct lu_object *o)
700 LASSERT(atomic_read(&o->lo_header->loh_ref) > 0);
701 atomic_inc(&o->lo_header->loh_ref);
705 * Return true of object will not be cached after last reference to it is
708 static inline int lu_object_is_dying(const struct lu_object_header *h)
710 return test_bit(LU_OBJECT_HEARD_BANSHEE, &h->loh_flags);
713 void lu_object_put(const struct lu_env *env, struct lu_object *o);
714 void lu_object_unhash(const struct lu_env *env, struct lu_object *o);
715 int lu_site_purge_objects(const struct lu_env *env, struct lu_site *s, int nr,
718 static inline int lu_site_purge(const struct lu_env *env, struct lu_site *s,
721 return lu_site_purge_objects(env, s, nr, true);
724 void lu_site_print(const struct lu_env *env, struct lu_site *s, void *cookie,
725 lu_printer_t printer);
726 struct lu_object *lu_object_find_at(const struct lu_env *env,
727 struct lu_device *dev,
728 const struct lu_fid *f,
729 const struct lu_object_conf *conf);
730 struct lu_object *lu_object_find_slice(const struct lu_env *env,
731 struct lu_device *dev,
732 const struct lu_fid *f,
733 const struct lu_object_conf *conf);
742 * First (topmost) sub-object of given compound object
744 static inline struct lu_object *lu_object_top(struct lu_object_header *h)
746 LASSERT(!list_empty(&h->loh_layers));
747 return container_of0(h->loh_layers.next, struct lu_object, lo_linkage);
751 * Next sub-object in the layering
753 static inline struct lu_object *lu_object_next(const struct lu_object *o)
755 return container_of0(o->lo_linkage.next, struct lu_object, lo_linkage);
759 * Pointer to the fid of this object.
761 static inline const struct lu_fid *lu_object_fid(const struct lu_object *o)
763 return &o->lo_header->loh_fid;
767 * return device operations vector for this object
769 static inline const struct lu_device_operations *
770 lu_object_ops(const struct lu_object *o)
772 return o->lo_dev->ld_ops;
776 * Given a compound object, find its slice, corresponding to the device type
779 struct lu_object *lu_object_locate(struct lu_object_header *h,
780 const struct lu_device_type *dtype);
783 * Printer function emitting messages through libcfs_debug_msg().
785 int lu_cdebug_printer(const struct lu_env *env,
786 void *cookie, const char *format, ...);
789 * Print object description followed by a user-supplied message.
791 #define LU_OBJECT_DEBUG(mask, env, object, format, ...) \
793 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
794 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
795 lu_object_print(env, &msgdata, lu_cdebug_printer, object);\
796 CDEBUG(mask, format "\n", ## __VA_ARGS__); \
801 * Print short object description followed by a user-supplied message.
803 #define LU_OBJECT_HEADER(mask, env, object, format, ...) \
805 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
806 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
807 lu_object_header_print(env, &msgdata, lu_cdebug_printer,\
808 (object)->lo_header); \
809 lu_cdebug_printer(env, &msgdata, "\n"); \
810 CDEBUG(mask, format, ## __VA_ARGS__); \
814 void lu_object_print (const struct lu_env *env, void *cookie,
815 lu_printer_t printer, const struct lu_object *o);
816 void lu_object_header_print(const struct lu_env *env, void *cookie,
817 lu_printer_t printer,
818 const struct lu_object_header *hdr);
821 * Check object consistency.
823 int lu_object_invariant(const struct lu_object *o);
826 * Check whether object exists, no matter on local or remote storage.
827 * Note: LOHA_EXISTS will be set once some one created the object,
828 * and it does not needs to be committed to storage.
830 #define lu_object_exists(o) ((o)->lo_header->loh_attr & LOHA_EXISTS)
833 * Check whether object on the remote storage.
835 #define lu_object_remote(o) unlikely((o)->lo_header->loh_attr & LOHA_REMOTE)
837 static inline int lu_object_assert_exists(const struct lu_object *o)
839 return lu_object_exists(o);
842 static inline int lu_object_assert_not_exists(const struct lu_object *o)
844 return !lu_object_exists(o);
848 * Attr of this object.
850 static inline __u32 lu_object_attr(const struct lu_object *o)
852 LASSERT(lu_object_exists(o) != 0);
853 return o->lo_header->loh_attr;
856 static inline void lu_object_ref_add(struct lu_object *o,
860 lu_ref_add(&o->lo_header->loh_reference, scope, source);
863 static inline void lu_object_ref_add_at(struct lu_object *o,
864 struct lu_ref_link *link,
868 lu_ref_add_at(&o->lo_header->loh_reference, link, scope, source);
871 static inline void lu_object_ref_del(struct lu_object *o,
872 const char *scope, const void *source)
874 lu_ref_del(&o->lo_header->loh_reference, scope, source);
877 static inline void lu_object_ref_del_at(struct lu_object *o,
878 struct lu_ref_link *link,
879 const char *scope, const void *source)
881 lu_ref_del_at(&o->lo_header->loh_reference, link, scope, source);
884 /** input params, should be filled out by mdt */
888 /** count in bytes */
889 unsigned int rp_count;
890 /** number of pages */
891 unsigned int rp_npages;
892 /** requested attr */
894 /** pointers to pages */
895 struct page **rp_pages;
898 enum lu_xattr_flags {
899 LU_XATTR_REPLACE = (1 << 0),
900 LU_XATTR_CREATE = (1 << 1)
909 /** For lu_context health-checks */
910 enum lu_context_state {
918 * lu_context. Execution context for lu_object methods. Currently associated
921 * All lu_object methods, except device and device type methods (called during
922 * system initialization and shutdown) are executed "within" some
923 * lu_context. This means, that pointer to some "current" lu_context is passed
924 * as an argument to all methods.
926 * All service ptlrpc threads create lu_context as part of their
927 * initialization. It is possible to create "stand-alone" context for other
928 * execution environments (like system calls).
930 * lu_object methods mainly use lu_context through lu_context_key interface
931 * that allows each layer to associate arbitrary pieces of data with each
932 * context (see pthread_key_create(3) for similar interface).
934 * On a client, lu_context is bound to a thread, see cl_env_get().
936 * \see lu_context_key
940 * lu_context is used on the client side too. Yet we don't want to
941 * allocate values of server-side keys for the client contexts and
944 * To achieve this, set of tags in introduced. Contexts and keys are
945 * marked with tags. Key value are created only for context whose set
946 * of tags has non-empty intersection with one for key. Tags are taken
947 * from enum lu_context_tag.
950 enum lu_context_state lc_state;
952 * Pointer to the home service thread. NULL for other execution
955 struct ptlrpc_thread *lc_thread;
957 * Pointer to an array with key values. Internal implementation
962 * Linkage into a list of all remembered contexts. Only
963 * `non-transient' contexts, i.e., ones created for service threads
966 struct list_head lc_remember;
968 * Version counter used to skip calls to lu_context_refill() when no
969 * keys were registered.
971 unsigned int lc_version;
975 unsigned int lc_cookie;
979 * lu_context_key interface. Similar to pthread_key.
982 enum lu_context_tag {
984 * Thread on md server
986 LCT_MD_THREAD = 1 << 0,
988 * Thread on dt server
990 LCT_DT_THREAD = 1 << 1,
992 * Context for transaction handle
994 LCT_TX_HANDLE = 1 << 2,
998 LCT_CL_THREAD = 1 << 3,
1000 * A per-request session on a server, and a per-system-call session on
1003 LCT_SESSION = 1 << 4,
1005 * A per-request data on OSP device
1007 LCT_OSP_THREAD = 1 << 5,
1011 LCT_MG_THREAD = 1 << 6,
1013 * Context for local operations
1017 * session for server thread
1019 LCT_SERVER_SESSION = BIT(8),
1021 * Set when at least one of keys, having values in this context has
1022 * non-NULL lu_context_key::lct_exit() method. This is used to
1023 * optimize lu_context_exit() call.
1025 LCT_HAS_EXIT = 1 << 28,
1027 * Don't add references for modules creating key values in that context.
1028 * This is only for contexts used internally by lu_object framework.
1030 LCT_NOREF = 1 << 29,
1032 * Key is being prepared for retiring, don't create new values for it.
1034 LCT_QUIESCENT = 1 << 30,
1036 * Context should be remembered.
1038 LCT_REMEMBER = 1 << 31,
1040 * Contexts usable in cache shrinker thread.
1042 LCT_SHRINKER = LCT_MD_THREAD | LCT_DT_THREAD | LCT_CL_THREAD |
1047 * Key. Represents per-context value slot.
1049 * Keys are usually registered when module owning the key is initialized, and
1050 * de-registered when module is unloaded. Once key is registered, all new
1051 * contexts with matching tags, will get key value. "Old" contexts, already
1052 * initialized at the time of key registration, can be forced to get key value
1053 * by calling lu_context_refill().
1055 * Every key value is counted in lu_context_key::lct_used and acquires a
1056 * reference on an owning module. This means, that all key values have to be
1057 * destroyed before module can be unloaded. This is usually achieved by
1058 * stopping threads started by the module, that created contexts in their
1059 * entry functions. Situation is complicated by the threads shared by multiple
1060 * modules, like ptlrpcd daemon on a client. To work around this problem,
1061 * contexts, created in such threads, are `remembered' (see
1062 * LCT_REMEMBER)---i.e., added into a global list. When module is preparing
1063 * for unloading it does the following:
1065 * - marks its keys as `quiescent' (lu_context_tag::LCT_QUIESCENT)
1066 * preventing new key values from being allocated in the new contexts,
1069 * - scans a list of remembered contexts, destroying values of module
1070 * keys, thus releasing references to the module.
1072 * This is done by lu_context_key_quiesce(). If module is re-activated
1073 * before key has been de-registered, lu_context_key_revive() call clears
1074 * `quiescent' marker.
1076 * lu_context code doesn't provide any internal synchronization for these
1077 * activities---it's assumed that startup (including threads start-up) and
1078 * shutdown are serialized by some external means.
1082 struct lu_context_key {
1084 * Set of tags for which values of this key are to be instantiated.
1088 * Value constructor. This is called when new value is created for a
1089 * context. Returns pointer to new value of error pointer.
1091 void *(*lct_init)(const struct lu_context *ctx,
1092 struct lu_context_key *key);
1094 * Value destructor. Called when context with previously allocated
1095 * value of this slot is destroyed. \a data is a value that was returned
1096 * by a matching call to lu_context_key::lct_init().
1098 void (*lct_fini)(const struct lu_context *ctx,
1099 struct lu_context_key *key, void *data);
1101 * Optional method called on lu_context_exit() for all allocated
1102 * keys. Can be used by debugging code checking that locks are
1105 void (*lct_exit)(const struct lu_context *ctx,
1106 struct lu_context_key *key, void *data);
1108 * Internal implementation detail: index within lu_context::lc_value[]
1109 * reserved for this key.
1113 * Internal implementation detail: number of values created for this
1118 * Internal implementation detail: module for this key.
1120 struct module *lct_owner;
1122 * References to this key. For debugging.
1124 struct lu_ref lct_reference;
1127 #define LU_KEY_INIT(mod, type) \
1128 static void *mod##_key_init(const struct lu_context *ctx, \
1129 struct lu_context_key *key) \
1133 BUILD_BUG_ON(PAGE_SIZE < sizeof(*value)); \
1135 value = kzalloc(sizeof(*value), GFP_NOFS); \
1137 value = ERR_PTR(-ENOMEM); \
1141 struct __##mod##__dummy_init {; } /* semicolon catcher */
1143 #define LU_KEY_FINI(mod, type) \
1144 static void mod##_key_fini(const struct lu_context *ctx, \
1145 struct lu_context_key *key, void *data) \
1147 type *info = data; \
1151 struct __##mod##__dummy_fini {; } /* semicolon catcher */
1153 #define LU_KEY_INIT_FINI(mod, type) \
1154 LU_KEY_INIT(mod, type); \
1155 LU_KEY_FINI(mod, type)
1157 #define LU_CONTEXT_KEY_DEFINE(mod, tags) \
1158 struct lu_context_key mod##_thread_key = { \
1160 .lct_init = mod##_key_init, \
1161 .lct_fini = mod##_key_fini \
1164 #define LU_CONTEXT_KEY_INIT(key) \
1166 (key)->lct_owner = THIS_MODULE; \
1169 int lu_context_key_register(struct lu_context_key *key);
1170 void lu_context_key_degister(struct lu_context_key *key);
1171 void *lu_context_key_get(const struct lu_context *ctx,
1172 const struct lu_context_key *key);
1173 void lu_context_key_quiesce(struct lu_context_key *key);
1174 void lu_context_key_revive(struct lu_context_key *key);
1177 * LU_KEY_INIT_GENERIC() has to be a macro to correctly determine an
1181 #define LU_KEY_INIT_GENERIC(mod) \
1182 static void mod##_key_init_generic(struct lu_context_key *k, ...) \
1184 struct lu_context_key *key = k; \
1187 va_start(args, k); \
1189 LU_CONTEXT_KEY_INIT(key); \
1190 key = va_arg(args, struct lu_context_key *); \
1195 #define LU_TYPE_INIT(mod, ...) \
1196 LU_KEY_INIT_GENERIC(mod) \
1197 static int mod##_type_init(struct lu_device_type *t) \
1199 mod##_key_init_generic(__VA_ARGS__, NULL); \
1200 return lu_context_key_register_many(__VA_ARGS__, NULL); \
1202 struct __##mod##_dummy_type_init {; }
1204 #define LU_TYPE_FINI(mod, ...) \
1205 static void mod##_type_fini(struct lu_device_type *t) \
1207 lu_context_key_degister_many(__VA_ARGS__, NULL); \
1209 struct __##mod##_dummy_type_fini {; }
1211 #define LU_TYPE_START(mod, ...) \
1212 static void mod##_type_start(struct lu_device_type *t) \
1214 lu_context_key_revive_many(__VA_ARGS__, NULL); \
1216 struct __##mod##_dummy_type_start {; }
1218 #define LU_TYPE_STOP(mod, ...) \
1219 static void mod##_type_stop(struct lu_device_type *t) \
1221 lu_context_key_quiesce_many(__VA_ARGS__, NULL); \
1223 struct __##mod##_dummy_type_stop {; }
1225 #define LU_TYPE_INIT_FINI(mod, ...) \
1226 LU_TYPE_INIT(mod, __VA_ARGS__); \
1227 LU_TYPE_FINI(mod, __VA_ARGS__); \
1228 LU_TYPE_START(mod, __VA_ARGS__); \
1229 LU_TYPE_STOP(mod, __VA_ARGS__)
1231 int lu_context_init(struct lu_context *ctx, __u32 tags);
1232 void lu_context_fini(struct lu_context *ctx);
1233 void lu_context_enter(struct lu_context *ctx);
1234 void lu_context_exit(struct lu_context *ctx);
1235 int lu_context_refill(struct lu_context *ctx);
1238 * Helper functions to operate on multiple keys. These are used by the default
1239 * device type operations, defined by LU_TYPE_INIT_FINI().
1242 int lu_context_key_register_many(struct lu_context_key *k, ...);
1243 void lu_context_key_degister_many(struct lu_context_key *k, ...);
1244 void lu_context_key_revive_many(struct lu_context_key *k, ...);
1245 void lu_context_key_quiesce_many(struct lu_context_key *k, ...);
1252 * "Local" context, used to store data instead of stack.
1254 struct lu_context le_ctx;
1256 * "Session" context for per-request data.
1258 struct lu_context *le_ses;
1261 int lu_env_init(struct lu_env *env, __u32 tags);
1262 void lu_env_fini(struct lu_env *env);
1263 int lu_env_refill(struct lu_env *env);
1265 /** @} lu_context */
1268 * Output site statistical counters into a buffer. Suitable for
1269 * ll_rd_*()-style functions.
1271 int lu_site_stats_print(const struct lu_site *s, struct seq_file *m);
1274 * Common name structure to be passed around for various name related methods.
1277 const char *ln_name;
1282 * Validate names (path components)
1284 * To be valid \a name must be non-empty, '\0' terminated of length \a
1285 * name_len, and not contain '/'. The maximum length of a name (before
1286 * say -ENAMETOOLONG will be returned) is really controlled by llite
1287 * and the server. We only check for something insane coming from bad
1288 * integer handling here.
1290 static inline bool lu_name_is_valid_2(const char *name, size_t name_len)
1292 return name && name_len > 0 && name_len < INT_MAX &&
1293 name[name_len] == '\0' && strlen(name) == name_len &&
1294 !memchr(name, '/', name_len);
1298 * Common buffer structure to be passed around for various xattr_{s,g}et()
1306 #define DLUBUF "(%p %zu)"
1307 #define PLUBUF(buf) (buf)->lb_buf, (buf)->lb_len
1309 * One-time initializers, called at obdclass module initialization, not
1314 * Initialization of global lu_* data.
1316 int lu_global_init(void);
1319 * Dual to lu_global_init().
1321 void lu_global_fini(void);
1323 struct lu_kmem_descr {
1324 struct kmem_cache **ckd_cache;
1325 const char *ckd_name;
1326 const size_t ckd_size;
1329 int lu_kmem_init(struct lu_kmem_descr *caches);
1330 void lu_kmem_fini(struct lu_kmem_descr *caches);
1332 void lu_buf_free(struct lu_buf *buf);
1333 void lu_buf_alloc(struct lu_buf *buf, size_t size);
1334 void lu_buf_realloc(struct lu_buf *buf, size_t size);
1336 int lu_buf_check_and_grow(struct lu_buf *buf, size_t len);
1337 struct lu_buf *lu_buf_check_and_alloc(struct lu_buf *buf, size_t len);
1339 extern __u32 lu_context_tags_default;
1340 extern __u32 lu_session_tags_default;
1343 #endif /* __LUSTRE_LU_OBJECT_H */