1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
4 * Copyright (C) 2006 Cluster File Systems, Inc.
6 * This file is part of Lustre, http://www.lustre.org.
8 * Lustre is free software; you can redistribute it and/or
9 * modify it under the terms of version 2 of the GNU General Public
10 * License as published by the Free Software Foundation.
12 * Lustre is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with Lustre; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #ifndef __LUSTRE_LU_OBJECT_H
24 #define __LUSTRE_LU_OBJECT_H
29 #include <lustre/lustre_idl.h>
31 #include <libcfs/list.h>
32 #include <libcfs/kp30.h>
35 * Layered objects support for CMD3/C5.
40 struct proc_dir_entry;
44 * lu_* data-types represent server-side entities shared by data and meta-data
49 * 0. support for layering.
51 * Server side object is split into layers, one per device in the
52 * corresponding device stack. Individual layer is represented by struct
53 * lu_object. Compound layered object --- by struct lu_object_header. Most
54 * interface functions take lu_object as an argument and operate on the
55 * whole compound object. This decision was made due to the following
58 * - it's envisaged that lu_object will be used much more often than
61 * - we want lower (non-top) layers to be able to initiate operations
62 * on the whole object.
64 * Generic code supports layering more complex than simple stacking, e.g.,
65 * it is possible that at some layer object "spawns" multiple sub-objects
68 * 1. fid-based identification.
70 * Compound object is uniquely identified by its fid. Objects are indexed
71 * by their fids (hash table is used for index).
73 * 2. caching and life-cycle management.
75 * Object's life-time is controlled by reference counting. When reference
76 * count drops to 0, object is returned to cache. Cached objects still
77 * retain their identity (i.e., fid), and can be recovered from cache.
79 * Objects are kept in the global LRU list, and lu_site_purge() function
80 * can be used to reclaim given number of unused objects from the tail of
83 * 3. avoiding recursion.
85 * Generic code tries to replace recursion through layers by iterations
86 * where possible. Additionally to the end of reducing stack consumption,
87 * data, when practically possible, are allocated through lu_context_key
88 * interface rather than on stack.
95 struct lu_object_header;
98 * Operations common for data and meta-data devices.
100 struct lu_device_operations {
102 * Object creation protocol.
104 * Due to design goal of avoiding recursion, object creation (see
105 * lu_object_alloc()) is somewhat involved:
107 * - first, ->ldo_object_alloc() method of the top-level device
108 * in the stack is called. It should allocate top level object
109 * (including lu_object_header), but without any lower-layer
112 * - then lu_object_alloc() sets fid in the header of newly created
115 * - then ->loo_object_init() (a method from struct
116 * lu_object_operations) is called. It has to allocate lower-layer
117 * object(s). To do this, ->loo_object_init() calls
118 * ldo_object_alloc() of the lower-layer device(s).
120 * - for all new objects allocated by ->loo_object_init() (and
121 * inserted into object stack), ->loo_object_init() is called again
122 * repeatedly, until no new objects are created.
127 * Allocate object for the given device (without lower-layer
128 * parts). This is called by ->loo_object_init() from the parent
129 * layer, and should setup at least ->lo_dev and ->lo_ops fields of
130 * resulting lu_object.
132 * postcondition: ergo(!IS_ERR(result), result->lo_dev == d &&
133 * result->lo_ops != NULL);
135 struct lu_object *(*ldo_object_alloc)(const struct lu_context *ctx,
136 const struct lu_object_header *h,
137 struct lu_device *d);
139 * process config specific for device
141 int (*ldo_process_config)(const struct lu_context *ctx,
142 struct lu_device *, struct lustre_cfg *);
143 int (*ldo_recovery_complete)(const struct lu_context *,
149 * Type of "printer" function used by ->loo_object_print() method.
151 * Printer function is needed to provide some flexibility in (semi-)debugging
152 * output: possible implementations: printk, CDEBUG, sysfs/seq_file
154 typedef int (*lu_printer_t)(const struct lu_context *ctx,
155 void *cookie, const char *format, ...)
156 __attribute__ ((format (printf, 3, 4)));
159 * Operations specific for particular lu_object.
161 struct lu_object_operations {
164 * Allocate lower-layer parts of the object by calling
165 * ->ldo_object_alloc() of the corresponding underlying device.
167 * This method is called once for each object inserted into object
168 * stack. It's responsibility of this method to insert lower-layer
169 * object(s) it create into appropriate places of object stack.
171 int (*loo_object_init)(const struct lu_context *ctx,
172 struct lu_object *o);
174 * Called (in top-to-bottom order) during object allocation after all
175 * layers were allocated and initialized. Can be used to perform
176 * initialization depending on lower layers.
178 int (*loo_object_start)(const struct lu_context *ctx,
179 struct lu_object *o);
181 * Called before ->loo_object_free() to signal that object is being
182 * destroyed. Dual to ->loo_object_init().
184 void (*loo_object_delete)(const struct lu_context *ctx,
185 struct lu_object *o);
188 * Dual to ->ldo_object_alloc(). Called when object is removed from
191 void (*loo_object_free)(const struct lu_context *ctx,
192 struct lu_object *o);
195 * Called when last active reference to the object is released (and
196 * object returns to the cache). This method is optional.
198 void (*loo_object_release)(const struct lu_context *ctx,
199 struct lu_object *o);
201 * Debugging helper. Print given object.
203 int (*loo_object_print)(const struct lu_context *ctx, void *cookie,
204 lu_printer_t p, const struct lu_object *o);
206 * Optional debugging method. Returns true iff method is internally
209 int (*loo_object_invariant)(const struct lu_object *o);
215 struct lu_device_type;
218 * Device: a layer in the server side abstraction stacking.
222 * reference count. This is incremented, in particular, on each object
223 * created at this layer.
225 * XXX which means that atomic_t is probably too small.
229 * Pointer to device type. Never modified once set.
231 struct lu_device_type *ld_type;
233 * Operation vector for this device.
235 struct lu_device_operations *ld_ops;
237 * Stack this device belongs to.
239 struct lu_site *ld_site;
240 struct proc_dir_entry *ld_proc_entry;
242 /* XXX: temporary back pointer into obd. */
243 struct obd_device *ld_obd;
246 struct lu_device_type_operations;
249 * Tag bits for device type. They are used to distinguish certain groups of
253 /* this is meta-data device */
254 LU_DEVICE_MD = (1 << 0),
255 /* this is data device */
256 LU_DEVICE_DT = (1 << 1)
262 struct lu_device_type {
264 * Tag bits. Taken from enum lu_device_tag. Never modified once set.
268 * Name of this class. Unique system-wide. Never modified once set.
272 * Operations for this type.
274 struct lu_device_type_operations *ldt_ops;
276 * XXX: temporary pointer to associated obd_type.
278 struct obd_type *ldt_obd_type;
280 * XXX: temporary: context tags used by obd_*() calls.
286 * Operations on a device type.
288 struct lu_device_type_operations {
290 * Allocate new device.
292 struct lu_device *(*ldto_device_alloc)(const struct lu_context *ctx,
293 struct lu_device_type *t,
294 struct lustre_cfg *lcfg);
296 * Free device. Dual to ->ldto_device_alloc().
298 void (*ldto_device_free)(const struct lu_context *,
302 * Initialize the devices after allocation
304 int (*ldto_device_init)(const struct lu_context *ctx,
305 struct lu_device *, struct lu_device *);
307 * Finalize device. Dual to ->ldto_device_init(). Returns pointer to
308 * the next device in the stack.
310 struct lu_device *(*ldto_device_fini)(const struct lu_context *ctx,
314 * Initialize device type. This is called on module load.
316 int (*ldto_init)(struct lu_device_type *t);
318 * Finalize device type. Dual to ->ldto_init(). Called on module
321 void (*ldto_fini)(struct lu_device_type *t);
325 * Flags for the object layers.
327 enum lu_object_flags {
329 * this flags is set if ->loo_object_init() has been called for this
330 * layer. Used by lu_object_alloc().
332 LU_OBJECT_ALLOCATED = (1 << 0)
336 * Common object attributes.
353 LA_BLKSIZE = 1 << 12,
357 __u64 la_size; /* size in bytes */
358 __u64 la_mtime; /* modification time in seconds since Epoch */
359 __u64 la_atime; /* access time in seconds since Epoch */
360 __u64 la_ctime; /* change time in seconds since Epoch */
361 __u64 la_blocks; /* 512-byte blocks allocated to object */
362 __u32 la_mode; /* permission bits and file type */
363 __u32 la_uid; /* owner id */
364 __u32 la_gid; /* group id */
365 __u32 la_flags; /* object flags */
366 __u32 la_nlink; /* number of persistent references to this
368 __u32 la_blksize; /* blk size of the object*/
370 __u32 la_rdev; /* real device */
371 __u64 la_valid; /* valid bits */
376 * Layer in the layered object.
380 * Header for this object.
382 struct lu_object_header *lo_header;
384 * Device for this layer.
386 struct lu_device *lo_dev;
388 * Operations for this object.
390 struct lu_object_operations *lo_ops;
392 * Linkage into list of all layers.
394 struct list_head lo_linkage;
396 * Depth. Top level layer depth is 0.
400 * Flags from enum lu_object_flags.
402 unsigned long lo_flags;
405 enum lu_object_header_flags {
407 * Don't keep this object in cache. Object will be destroyed as soon
408 * as last reference to it is released. This flag cannot be cleared
411 LU_OBJECT_HEARD_BANSHEE = 0,
414 enum lu_object_header_attr {
415 LOHA_EXISTS = 1 << 0,
416 LOHA_REMOTE = 1 << 1,
418 * UNIX file type is stored in S_IFMT bits.
420 LOHA_FT_START = 1 << 12, /* S_IFIFO */
421 LOHA_FT_END = 1 << 15, /* S_IFREG */
425 * "Compound" object, consisting of multiple layers.
427 * Compound object with given fid is unique with given lu_site.
429 * Note, that object does *not* necessary correspond to the real object in the
430 * persistent storage: object is an anchor for locking and method calling, so
431 * it is created for things like not-yet-existing child created by mkdir or
432 * create calls. ->loo_exists() can be used to check whether object is backed
433 * by persistent storage entity.
435 struct lu_object_header {
437 * Object flags from enum lu_object_header_flags. Set and checked
440 unsigned long loh_flags;
442 * Object reference count. Protected by site guard lock.
446 * Fid, uniquely identifying this object.
448 struct lu_fid loh_fid;
450 * Common object attributes, cached for efficiency. From enum
451 * lu_object_header_attr.
455 * Linkage into per-site hash table. Protected by site guard lock.
457 struct hlist_node loh_hash;
459 * Linkage into per-site LRU list. Protected by site guard lock.
461 struct list_head loh_lru;
463 * Linkage into list of layers. Never modified once set (except lately
464 * during object destruction). No locking is necessary.
466 struct list_head loh_layers;
472 * lu_site is a "compartment" within which objects are unique, and LRU
473 * discipline is maintained.
475 * lu_site exists so that multiple layered stacks can co-exist in the same
478 * lu_site has the same relation to lu_device as lu_object_header to
485 * - ->ls_hash hash table (and its linkages in objects);
487 * - ->ls_lru list (and its linkages in objects);
489 * - 0/1 transitions of object ->loh_ref reference count;
495 * Hash-table where objects are indexed by fid.
497 struct hlist_head *ls_hash;
499 * Bit-mask for hash-table size.
504 * LRU list, updated on each access to object. Protected by
507 * "Cold" end of LRU is ->ls_lru.next. Accessed object are moved to
508 * the ->ls_lru.prev (this is due to the non-existence of
509 * list_for_each_entry_safe_reverse()).
511 struct list_head ls_lru;
513 * Total number of objects in this site. Protected by ->ls_guard.
517 * Total number of objects in this site with reference counter greater
518 * than 0. Protected by ->ls_guard.
523 * Top-level device for this stack.
525 struct lu_device *ls_top_dev;
527 * mds number of this site.
531 * Fid location database
533 struct lu_server_fld *ls_server_fld;
534 struct lu_client_fld *ls_client_fld;
539 struct lu_server_seq *ls_server_seq;
542 * Controller Seq Manager
544 struct lu_server_seq *ls_control_seq;
549 struct lu_client_seq *ls_client_seq;
550 struct obd_export *ls_client_exp;
552 /* statistical counters. Protected by nothing, races are accepted. */
558 * Number of hash-table entry checks made.
560 * ->s_cache_check / (->s_cache_miss + ->s_cache_hit)
562 * is an average number of hash slots inspected during single
566 /* raced cache insertions */
573 * Constructors/destructors.
577 * Initialize site @s, with @d as the top level device.
579 int lu_site_init(struct lu_site *s, struct lu_device *d);
581 * Finalize @s and release its resources.
583 void lu_site_fini(struct lu_site *s);
586 * Acquire additional reference on device @d
588 void lu_device_get(struct lu_device *d);
590 * Release reference on device @d.
592 void lu_device_put(struct lu_device *d);
595 * Initialize device @d of type @t.
597 int lu_device_init(struct lu_device *d, struct lu_device_type *t);
599 * Finalize device @d.
601 void lu_device_fini(struct lu_device *d);
604 * Initialize compound object.
606 int lu_object_header_init(struct lu_object_header *h);
608 * Finalize compound object.
610 void lu_object_header_fini(struct lu_object_header *h);
613 * Initialize object @o that is part of compound object @h and was created by
616 int lu_object_init(struct lu_object *o,
617 struct lu_object_header *h, struct lu_device *d);
619 * Finalize object and release its resources.
621 void lu_object_fini(struct lu_object *o);
623 * Add object @o as first layer of compound object @h.
625 * This is typically called by the ->ldo_object_alloc() method of top-level
628 void lu_object_add_top(struct lu_object_header *h, struct lu_object *o);
630 * Add object @o as a layer of compound object, going after @before.1
632 * This is typically called by the ->ldo_object_alloc() method of
635 void lu_object_add(struct lu_object *before, struct lu_object *o);
638 * Caching and reference counting.
642 * Acquire additional reference to the given object. This function is used to
643 * attain additional reference. To acquire initial reference use
646 static inline void lu_object_get(struct lu_object *o)
648 LASSERT(o->lo_header->loh_ref > 0);
649 spin_lock(&o->lo_dev->ld_site->ls_guard);
650 o->lo_header->loh_ref ++;
651 spin_unlock(&o->lo_dev->ld_site->ls_guard);
655 * Return true of object will not be cached after last reference to it is
658 static inline int lu_object_is_dying(const struct lu_object_header *h)
660 return test_bit(LU_OBJECT_HEARD_BANSHEE, &h->loh_flags);
664 * Decrease reference counter on object. If last reference is freed, return
665 * object to the cache, unless lu_object_is_dying(o) holds. In the latter
666 * case, free object immediately.
668 void lu_object_put(const struct lu_context *ctxt,
669 struct lu_object *o);
672 * Free @nr objects from the cold end of the site LRU list.
674 void lu_site_purge(const struct lu_context *ctx,
675 struct lu_site *s, int nr);
678 * Search cache for an object with the fid @f. If such object is found, return
679 * it. Otherwise, create new object, insert it into cache and return it. In
680 * any case, additional reference is acquired on the returned object.
682 struct lu_object *lu_object_find(const struct lu_context *ctxt,
683 struct lu_site *s, const struct lu_fid *f);
690 * First (topmost) sub-object of given compound object
692 static inline struct lu_object *lu_object_top(struct lu_object_header *h)
694 LASSERT(!list_empty(&h->loh_layers));
695 return container_of0(h->loh_layers.next, struct lu_object, lo_linkage);
699 * Next sub-object in the layering
701 static inline struct lu_object *lu_object_next(const struct lu_object *o)
703 return container_of0(o->lo_linkage.next, struct lu_object, lo_linkage);
707 * Pointer to the fid of this object.
709 static inline const struct lu_fid *lu_object_fid(const struct lu_object *o)
711 return &o->lo_header->loh_fid;
715 * return device operations vector for this object
717 static inline struct lu_device_operations *
718 lu_object_ops(const struct lu_object *o)
720 return o->lo_dev->ld_ops;
724 * Given a compound object, find its slice, corresponding to the device type
727 struct lu_object *lu_object_locate(struct lu_object_header *h,
728 struct lu_device_type *dtype);
730 struct lu_cdebug_print_info {
733 const char *lpi_file;
739 * Printer function emitting messages through libcfs_debug_msg().
741 int lu_cdebug_printer(const struct lu_context *ctx,
742 void *cookie, const char *format, ...);
745 * Print object description followed by user-supplied message.
747 #define LU_OBJECT_DEBUG(mask, ctx, object, format, ...) \
749 static struct lu_cdebug_print_info __info = { \
750 .lpi_subsys = DEBUG_SUBSYSTEM, \
751 .lpi_mask = (mask), \
752 .lpi_file = __FILE__, \
753 .lpi_fn = __FUNCTION__, \
754 .lpi_line = __LINE__ \
756 lu_object_print(ctx, &__info, lu_cdebug_printer, object); \
757 CDEBUG(mask, format , ## __VA_ARGS__); \
761 * Print human readable representation of the @o to the @f.
763 void lu_object_print(const struct lu_context *ctxt, void *cookie,
764 lu_printer_t printer, const struct lu_object *o);
767 * Check object consistency.
769 int lu_object_invariant(const struct lu_object *o);
772 * Returns 1 iff object @o exists on the stable storage,
773 * returns -1 iff object @o is on remote server.
775 static inline int lu_object_exists(const struct lu_object *o)
779 attr = o->lo_header->loh_attr;
780 if (attr & LOHA_REMOTE)
782 else if (attr & LOHA_EXISTS)
788 static inline int lu_object_assert_exists(const struct lu_object *o)
790 return lu_object_exists(o) != 0;
793 static inline int lu_object_assert_not_exists(const struct lu_object *o)
795 return lu_object_exists(o) <= 0;
799 * Attr of this object.
801 static inline const __u32 lu_object_attr(const struct lu_object *o)
803 LASSERT(lu_object_exists(o) > 0);
804 return o->lo_header->loh_attr;
808 /* input params, should be filled out by mdt */
809 __u32 rp_hash; /* hash */
810 int rp_count; /* count in bytes */
811 int rp_npages; /* number of pages */
812 struct page **rp_pages; /* pointers to pages */
815 enum lu_xattr_flags {
816 LU_XATTR_REPLACE = (1 << 0),
817 LU_XATTR_CREATE = (1 << 1)
821 * lu_context. Execution context for lu_object methods. Currently associated
824 * All lu_object methods, except device and device type methods (called during
825 * system initialization and shutdown) are executed "within" some
826 * lu_context. This means, that pointer to some "current" lu_context is passed
827 * as an argument to all methods.
829 * All service ptlrpc threads create lu_context as part of their
830 * initialization. It is possible to create "stand-alone" context for other
831 * execution environments (like system calls).
833 * lu_object methods mainly use lu_context through lu_context_key interface
834 * that allows each layer to associate arbitrary pieces of data with each
835 * context (see pthread_key_create(3) for similar interface).
840 * Theoretically we'd want to use lu_objects and lu_contexts on the
841 * client side too. On the other hand, we don't want to allocate
842 * values of server-side keys for the client contexts and vice versa.
844 * To achieve this, set of tags in introduced. Contexts and keys are
845 * marked with tags. Key value are created only for context whose set
846 * of tags has non-empty intersection with one for key. Tags are taken
847 * from enum lu_context_tag.
851 * Pointer to the home service thread. NULL for other execution
854 struct ptlrpc_thread *lc_thread;
856 * Pointer to an array with key values. Internal implementation
863 * lu_context_key interface. Similar to pthread_key.
866 enum lu_context_tag {
867 LCT_MD_THREAD = 1 << 0,
868 LCT_DT_THREAD = 1 << 1,
869 LCT_TX_HANDLE = 1 << 2,
870 LCT_CL_THREAD = 1 << 3
874 * Key. Represents per-context value slot.
876 struct lu_context_key {
878 * Set of tags for which values of this key are to be instantiated.
882 * Value constructor. This is called when new value is created for a
883 * context. Returns pointer to new value of error pointer.
885 void *(*lct_init)(const struct lu_context *ctx,
886 struct lu_context_key *key);
888 * Value destructor. Called when context with previously allocated
889 * value of this slot is destroyed. @data is a value that was returned
890 * by a matching call to ->lct_init().
892 void (*lct_fini)(const struct lu_context *ctx,
893 struct lu_context_key *key, void *data);
895 * Optional method called on lu_context_exit() for all allocated
896 * keys. Can be used by debugging code checking that locks are
899 void (*lct_exit)(const struct lu_context *ctx,
900 struct lu_context_key *key, void *data);
902 * Internal implementation detail: index within ->lc_value[] reserved
907 * Internal implementation detail: number of values created for this
916 int lu_context_key_register(struct lu_context_key *key);
920 void lu_context_key_degister(struct lu_context_key *key);
922 * Return value associated with key @key in context @ctx.
924 void *lu_context_key_get(const struct lu_context *ctx,
925 struct lu_context_key *key);
928 * Initialize context data-structure. Create values for all keys.
930 int lu_context_init(struct lu_context *ctx, __u32 tags);
932 * Finalize context data-structure. Destroy key values.
934 void lu_context_fini(struct lu_context *ctx);
937 * Called before entering context.
939 void lu_context_enter(struct lu_context *ctx);
941 * Called after exiting from @ctx
943 void lu_context_exit(struct lu_context *ctx);
946 * Allocate for context all missing keys that were registered after context
949 int lu_context_refill(const struct lu_context *ctx);
952 * One-time initializers, called at obdclass module initialization, not
957 * Initialization of global lu_* data.
959 int lu_global_init(void);
962 * Dual to lu_global_init().
964 void lu_global_fini(void);
966 #endif /* __LUSTRE_LU_OBJECT_H */