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36 #ifndef _LUSTRE_CL_OBJECT_H
37 #define _LUSTRE_CL_OBJECT_H
39 /** \defgroup clio clio
41 * Client objects implement io operations and cache pages.
43 * Examples: lov and osc are implementations of cl interface.
45 * Big Theory Statement.
49 * Client implementation is based on the following data-types:
55 * - cl_lock represents an extent lock on an object.
57 * - cl_io represents high-level i/o activity such as whole read/write
58 * system call, or write-out of pages from under the lock being
59 * canceled. cl_io has sub-ios that can be stopped and resumed
60 * independently, thus achieving high degree of transfer
61 * parallelism. Single cl_io can be advanced forward by
62 * the multiple threads (although in the most usual case of
63 * read/write system call it is associated with the single user
64 * thread, that issued the system call).
68 * - to avoid confusion high-level I/O operation like read or write system
69 * call is referred to as "an io", whereas low-level I/O operation, like
70 * RPC, is referred to as "a transfer"
72 * - "generic code" means generic (not file system specific) code in the
73 * hosting environment. "cl-code" means code (mostly in cl_*.c files) that
74 * is not layer specific.
80 * - cl_object_header::coh_page_guard
83 * See the top comment in cl_object.c for the description of overall locking and
84 * reference-counting design.
86 * See comments below for the description of i/o, page, and dlm-locking
93 * super-class definitions.
95 #include <libcfs/libcfs.h>
96 #include <lu_object.h>
97 #include <linux/atomic.h>
98 #include <linux/mutex.h>
99 #include <linux/radix-tree.h>
100 #include <linux/spinlock.h>
101 #include <linux/wait.h>
102 #include <lustre_dlm.h>
112 struct cl_page_slice;
114 struct cl_lock_slice;
116 struct cl_lock_operations;
117 struct cl_page_operations;
125 * Device in the client stack.
127 * \see vvp_device, lov_device, lovsub_device, osc_device
131 struct lu_device cd_lu_dev;
134 /** \addtogroup cl_object cl_object
137 * "Data attributes" of cl_object. Data attributes can be updated
138 * independently for a sub-object, and top-object's attributes are calculated
139 * from sub-objects' ones.
142 /** Object size, in bytes */
145 * Known minimal size, in bytes.
147 * This is only valid when at least one DLM lock is held.
150 /** Modification time. Measured in seconds since epoch. */
152 /** Access time. Measured in seconds since epoch. */
154 /** Change time. Measured in seconds since epoch. */
157 * Blocks allocated to this cl_object on the server file system.
159 * \todo XXX An interface for block size is needed.
163 * User identifier for quota purposes.
167 * Group identifier for quota purposes.
171 /* nlink of the directory */
176 * Fields in cl_attr that are being set.
190 * Sub-class of lu_object with methods common for objects on the client
193 * cl_object: represents a regular file system object, both a file and a
194 * stripe. cl_object is based on lu_object: it is identified by a fid,
195 * layered, cached, hashed, and lrued. Important distinction with the server
196 * side, where md_object and dt_object are used, is that cl_object "fans out"
197 * at the lov/sns level: depending on the file layout, single file is
198 * represented as a set of "sub-objects" (stripes). At the implementation
199 * level, struct lov_object contains an array of cl_objects. Each sub-object
200 * is a full-fledged cl_object, having its fid, living in the lru and hash
203 * This leads to the next important difference with the server side: on the
204 * client, it's quite usual to have objects with the different sequence of
205 * layers. For example, typical top-object is composed of the following
211 * whereas its sub-objects are composed of
216 * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep
217 * track of the object-subobject relationship.
219 * Sub-objects are not cached independently: when top-object is about to
220 * be discarded from the memory, all its sub-objects are torn-down and
223 * \see vvp_object, lov_object, lovsub_object, osc_object
227 struct lu_object co_lu;
228 /** per-object-layer operations */
229 const struct cl_object_operations *co_ops;
230 /** offset of page slice in cl_page buffer */
235 * Description of the client object configuration. This is used for the
236 * creation of a new client object that is identified by a more state than
239 struct cl_object_conf {
241 struct lu_object_conf coc_lu;
244 * Object layout. This is consumed by lov.
246 struct lu_buf coc_layout;
248 * Description of particular stripe location in the
249 * cluster. This is consumed by osc.
251 struct lov_oinfo *coc_oinfo;
254 * VFS inode. This is consumed by vvp.
256 struct inode *coc_inode;
258 * Layout lock handle.
260 struct ldlm_lock *coc_lock;
262 * Operation to handle layout, OBJECT_CONF_XYZ.
268 /** configure layout, set up a new stripe, must be called while
269 * holding layout lock. */
271 /** invalidate the current stripe configuration due to losing
273 OBJECT_CONF_INVALIDATE = 1,
274 /** wait for old layout to go away so that new layout can be
280 CL_LAYOUT_GEN_NONE = (u32)-2, /* layout lock was cancelled */
281 CL_LAYOUT_GEN_EMPTY = (u32)-1, /* for empty layout */
285 /** the buffer to return the layout in lov_mds_md format. */
286 struct lu_buf cl_buf;
287 /** size of layout in lov_mds_md format. */
289 /** Layout generation. */
294 * Operations implemented for each cl object layer.
296 * \see vvp_ops, lov_ops, lovsub_ops, osc_ops
298 struct cl_object_operations {
300 * Initialize page slice for this layer. Called top-to-bottom through
301 * every object layer when a new cl_page is instantiated. Layer
302 * keeping private per-page data, or requiring its own page operations
303 * vector should allocate these data here, and attach then to the page
304 * by calling cl_page_slice_add(). \a vmpage is locked (in the VM
307 * \retval NULL success.
309 * \retval ERR_PTR(errno) failure code.
311 * \retval valid-pointer pointer to already existing referenced page
312 * to be used instead of newly created.
314 int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj,
315 struct cl_page *page, pgoff_t index);
317 * Initialize lock slice for this layer. Called top-to-bottom through
318 * every object layer when a new cl_lock is instantiated. Layer
319 * keeping private per-lock data, or requiring its own lock operations
320 * vector should allocate these data here, and attach then to the lock
321 * by calling cl_lock_slice_add(). Mandatory.
323 int (*coo_lock_init)(const struct lu_env *env,
324 struct cl_object *obj, struct cl_lock *lock,
325 const struct cl_io *io);
327 * Initialize io state for a given layer.
329 * called top-to-bottom once per io existence to initialize io
330 * state. If layer wants to keep some state for this type of io, it
331 * has to embed struct cl_io_slice in lu_env::le_ses, and register
332 * slice with cl_io_slice_add(). It is guaranteed that all threads
333 * participating in this io share the same session.
335 int (*coo_io_init)(const struct lu_env *env,
336 struct cl_object *obj, struct cl_io *io);
338 * Fill portion of \a attr that this layer controls. This method is
339 * called top-to-bottom through all object layers.
341 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
343 * \return 0: to continue
344 * \return +ve: to stop iterating through layers (but 0 is returned
345 * from enclosing cl_object_attr_get())
346 * \return -ve: to signal error
348 int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj,
349 struct cl_attr *attr);
353 * \a valid is a bitmask composed from enum #cl_attr_valid, and
354 * indicating what attributes are to be set.
356 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
358 * \return the same convention as for
359 * cl_object_operations::coo_attr_get() is used.
361 int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj,
362 const struct cl_attr *attr, unsigned valid);
364 * Update object configuration. Called top-to-bottom to modify object
367 * XXX error conditions and handling.
369 int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj,
370 const struct cl_object_conf *conf);
372 * Glimpse ast. Executed when glimpse ast arrives for a lock on this
373 * object. Layers are supposed to fill parts of \a lvb that will be
374 * shipped to the glimpse originator as a glimpse result.
376 * \see vvp_object_glimpse(), lovsub_object_glimpse(),
377 * \see osc_object_glimpse()
379 int (*coo_glimpse)(const struct lu_env *env,
380 const struct cl_object *obj, struct ost_lvb *lvb);
382 * Object prune method. Called when the layout is going to change on
383 * this object, therefore each layer has to clean up their cache,
384 * mainly pages and locks.
386 int (*coo_prune)(const struct lu_env *env, struct cl_object *obj);
388 * Object getstripe method.
390 int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj,
391 struct lov_user_md __user *lum);
393 * Get FIEMAP mapping from the object.
395 int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj,
396 struct ll_fiemap_info_key *fmkey,
397 struct fiemap *fiemap, size_t *buflen);
399 * Get layout and generation of the object.
401 int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj,
402 struct cl_layout *layout);
404 * Get maximum size of the object.
406 loff_t (*coo_maxbytes)(struct cl_object *obj);
408 * Set request attributes.
410 void (*coo_req_attr_set)(const struct lu_env *env,
411 struct cl_object *obj,
412 struct cl_req_attr *attr);
416 * Extended header for client object.
418 struct cl_object_header {
419 /** Standard lu_object_header. cl_object::co_lu::lo_header points
421 struct lu_object_header coh_lu;
424 * Parent object. It is assumed that an object has a well-defined
425 * parent, but not a well-defined child (there may be multiple
426 * sub-objects, for the same top-object). cl_object_header::coh_parent
427 * field allows certain code to be written generically, without
428 * limiting possible cl_object layouts unduly.
430 struct cl_object_header *coh_parent;
432 * Protects consistency between cl_attr of parent object and
433 * attributes of sub-objects, that the former is calculated ("merged")
436 * \todo XXX this can be read/write lock if needed.
438 spinlock_t coh_attr_guard;
440 * Size of cl_page + page slices
442 unsigned short coh_page_bufsize;
444 * Number of objects above this one: 0 for a top-object, 1 for its
447 unsigned char coh_nesting;
451 * Helper macro: iterate over all layers of the object \a obj, assigning every
452 * layer top-to-bottom to \a slice.
454 #define cl_object_for_each(slice, obj) \
455 list_for_each_entry((slice), \
456 &(obj)->co_lu.lo_header->loh_layers,\
460 * Helper macro: iterate over all layers of the object \a obj, assigning every
461 * layer bottom-to-top to \a slice.
463 #define cl_object_for_each_reverse(slice, obj) \
464 list_for_each_entry_reverse((slice), \
465 &(obj)->co_lu.lo_header->loh_layers,\
470 #define CL_PAGE_EOF ((pgoff_t)~0ull)
472 /** \addtogroup cl_page cl_page
476 * Layered client page.
478 * cl_page: represents a portion of a file, cached in the memory. All pages
479 * of the given file are of the same size, and are kept in the radix tree
480 * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects
481 * of the top-level file object are first class cl_objects, they have their
482 * own radix trees of pages and hence page is implemented as a sequence of
483 * struct cl_pages's, linked into double-linked list through
484 * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the
485 * corresponding radix tree at the corresponding logical offset.
487 * cl_page is associated with VM page of the hosting environment (struct
488 * page in Linux kernel, for example), struct page. It is assumed, that this
489 * association is implemented by one of cl_page layers (top layer in the
490 * current design) that
492 * - intercepts per-VM-page call-backs made by the environment (e.g.,
495 * - translates state (page flag bits) and locking between lustre and
498 * The association between cl_page and struct page is immutable and
499 * established when cl_page is created.
501 * cl_page can be "owned" by a particular cl_io (see below), guaranteeing
502 * this io an exclusive access to this page w.r.t. other io attempts and
503 * various events changing page state (such as transfer completion, or
504 * eviction of the page from the memory). Note, that in general cl_io
505 * cannot be identified with a particular thread, and page ownership is not
506 * exactly equal to the current thread holding a lock on the page. Layer
507 * implementing association between cl_page and struct page has to implement
508 * ownership on top of available synchronization mechanisms.
510 * While lustre client maintains the notion of an page ownership by io,
511 * hosting MM/VM usually has its own page concurrency control
512 * mechanisms. For example, in Linux, page access is synchronized by the
513 * per-page PG_locked bit-lock, and generic kernel code (generic_file_*())
514 * takes care to acquire and release such locks as necessary around the
515 * calls to the file system methods (->readpage(), ->prepare_write(),
516 * ->commit_write(), etc.). This leads to the situation when there are two
517 * different ways to own a page in the client:
519 * - client code explicitly and voluntary owns the page (cl_page_own());
521 * - VM locks a page and then calls the client, that has "to assume"
522 * the ownership from the VM (cl_page_assume()).
524 * Dual methods to release ownership are cl_page_disown() and
525 * cl_page_unassume().
527 * cl_page is reference counted (cl_page::cp_ref). When reference counter
528 * drops to 0, the page is returned to the cache, unless it is in
529 * cl_page_state::CPS_FREEING state, in which case it is immediately
532 * The general logic guaranteeing the absence of "existential races" for
533 * pages is the following:
535 * - there are fixed known ways for a thread to obtain a new reference
538 * - by doing a lookup in the cl_object radix tree, protected by the
541 * - by starting from VM-locked struct page and following some
542 * hosting environment method (e.g., following ->private pointer in
543 * the case of Linux kernel), see cl_vmpage_page();
545 * - when the page enters cl_page_state::CPS_FREEING state, all these
546 * ways are severed with the proper synchronization
547 * (cl_page_delete());
549 * - entry into cl_page_state::CPS_FREEING is serialized by the VM page
552 * - no new references to the page in cl_page_state::CPS_FREEING state
553 * are allowed (checked in cl_page_get()).
555 * Together this guarantees that when last reference to a
556 * cl_page_state::CPS_FREEING page is released, it is safe to destroy the
557 * page, as neither references to it can be acquired at that point, nor
560 * cl_page is a state machine. States are enumerated in enum
561 * cl_page_state. Possible state transitions are enumerated in
562 * cl_page_state_set(). State transition process (i.e., actual changing of
563 * cl_page::cp_state field) is protected by the lock on the underlying VM
566 * Linux Kernel implementation.
568 * Binding between cl_page and struct page (which is a typedef for
569 * struct page) is implemented in the vvp layer. cl_page is attached to the
570 * ->private pointer of the struct page, together with the setting of
571 * PG_private bit in page->flags, and acquiring additional reference on the
572 * struct page (much like struct buffer_head, or any similar file system
573 * private data structures).
575 * PG_locked lock is used to implement both ownership and transfer
576 * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}}
577 * states. No additional references are acquired for the duration of the
580 * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where
581 * write-out is "protected" by the special PG_writeback bit.
585 * States of cl_page. cl_page.c assumes particular order here.
587 * The page state machine is rather crude, as it doesn't recognize finer page
588 * states like "dirty" or "up to date". This is because such states are not
589 * always well defined for the whole stack (see, for example, the
590 * implementation of the read-ahead, that hides page up-to-dateness to track
591 * cache hits accurately). Such sub-states are maintained by the layers that
592 * are interested in them.
596 * Page is in the cache, un-owned. Page leaves cached state in the
599 * - [cl_page_state::CPS_OWNED] io comes across the page and
602 * - [cl_page_state::CPS_PAGEOUT] page is dirty, the
603 * req-formation engine decides that it wants to include this page
604 * into an RPC being constructed, and yanks it from the cache;
606 * - [cl_page_state::CPS_FREEING] VM callback is executed to
607 * evict the page form the memory;
609 * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL
613 * Page is exclusively owned by some cl_io. Page may end up in this
614 * state as a result of
616 * - io creating new page and immediately owning it;
618 * - [cl_page_state::CPS_CACHED] io finding existing cached page
621 * - [cl_page_state::CPS_OWNED] io finding existing owned page
622 * and waiting for owner to release the page;
624 * Page leaves owned state in the following cases:
626 * - [cl_page_state::CPS_CACHED] io decides to leave the page in
627 * the cache, doing nothing;
629 * - [cl_page_state::CPS_PAGEIN] io starts read transfer for
632 * - [cl_page_state::CPS_PAGEOUT] io starts immediate write
633 * transfer for this page;
635 * - [cl_page_state::CPS_FREEING] io decides to destroy this
636 * page (e.g., as part of truncate or extent lock cancellation).
638 * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL
642 * Page is being written out, as a part of a transfer. This state is
643 * entered when req-formation logic decided that it wants this page to
644 * be sent through the wire _now_. Specifically, it means that once
645 * this state is achieved, transfer completion handler (with either
646 * success or failure indication) is guaranteed to be executed against
647 * this page independently of any locks and any scheduling decisions
648 * made by the hosting environment (that effectively means that the
649 * page is never put into cl_page_state::CPS_PAGEOUT state "in
650 * advance". This property is mentioned, because it is important when
651 * reasoning about possible dead-locks in the system). The page can
652 * enter this state as a result of
654 * - [cl_page_state::CPS_OWNED] an io requesting an immediate
655 * write-out of this page, or
657 * - [cl_page_state::CPS_CACHED] req-forming engine deciding
658 * that it has enough dirty pages cached to issue a "good"
661 * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer
662 * is completed---it is moved into cl_page_state::CPS_CACHED state.
664 * Underlying VM page is locked for the duration of transfer.
666 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
670 * Page is being read in, as a part of a transfer. This is quite
671 * similar to the cl_page_state::CPS_PAGEOUT state, except that
672 * read-in is always "immediate"---there is no such thing a sudden
673 * construction of read request from cached, presumably not up to date,
676 * Underlying VM page is locked for the duration of transfer.
678 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
682 * Page is being destroyed. This state is entered when client decides
683 * that page has to be deleted from its host object, as, e.g., a part
686 * Once this state is reached, there is no way to escape it.
688 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL
695 /** Host page, the page is from the host inode which the cl_page
699 /** Transient page, the transient cl_page is used to bind a cl_page
700 * to vmpage which is not belonging to the same object of cl_page.
701 * it is used in DirectIO, lockless IO and liblustre. */
706 * Fields are protected by the lock on struct page, except for atomics and
709 * \invariant Data type invariants are in cl_page_invariant(). Basically:
710 * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked
711 * list, consistent with the parent/child pointers in the cl_page::cp_obj and
712 * cl_page::cp_owner (when set).
715 /** Reference counter. */
717 /** An object this page is a part of. Immutable after creation. */
718 struct cl_object *cp_obj;
720 struct page *cp_vmpage;
721 /** Linkage of pages within group. Pages must be owned */
722 struct list_head cp_batch;
723 /** List of slices. Immutable after creation. */
724 struct list_head cp_layers;
726 * Page state. This field is const to avoid accidental update, it is
727 * modified only internally within cl_page.c. Protected by a VM lock.
729 const enum cl_page_state cp_state;
731 * Page type. Only CPT_TRANSIENT is used so far. Immutable after
734 enum cl_page_type cp_type;
737 * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned
738 * by sub-io. Protected by a VM lock.
740 struct cl_io *cp_owner;
741 /** List of references to this page, for debugging. */
742 struct lu_ref cp_reference;
743 /** Link to an object, for debugging. */
744 struct lu_ref_link cp_obj_ref;
745 /** Link to a queue, for debugging. */
746 struct lu_ref_link cp_queue_ref;
747 /** Assigned if doing a sync_io */
748 struct cl_sync_io *cp_sync_io;
752 * Per-layer part of cl_page.
754 * \see vvp_page, lov_page, osc_page
756 struct cl_page_slice {
757 struct cl_page *cpl_page;
760 * Object slice corresponding to this page slice. Immutable after
763 struct cl_object *cpl_obj;
764 const struct cl_page_operations *cpl_ops;
765 /** Linkage into cl_page::cp_layers. Immutable after creation. */
766 struct list_head cpl_linkage;
770 * Lock mode. For the client extent locks.
782 * Requested transfer type.
791 * Per-layer page operations.
793 * Methods taking an \a io argument are for the activity happening in the
794 * context of given \a io. Page is assumed to be owned by that io, except for
795 * the obvious cases (like cl_page_operations::cpo_own()).
797 * \see vvp_page_ops, lov_page_ops, osc_page_ops
799 struct cl_page_operations {
801 * cl_page<->struct page methods. Only one layer in the stack has to
802 * implement these. Current code assumes that this functionality is
803 * provided by the topmost layer, see cl_page_disown0() as an example.
807 * Called when \a io acquires this page into the exclusive
808 * ownership. When this method returns, it is guaranteed that the is
809 * not owned by other io, and no transfer is going on against
813 * \see vvp_page_own(), lov_page_own()
815 int (*cpo_own)(const struct lu_env *env,
816 const struct cl_page_slice *slice,
817 struct cl_io *io, int nonblock);
818 /** Called when ownership it yielded. Optional.
820 * \see cl_page_disown()
821 * \see vvp_page_disown()
823 void (*cpo_disown)(const struct lu_env *env,
824 const struct cl_page_slice *slice, struct cl_io *io);
826 * Called for a page that is already "owned" by \a io from VM point of
829 * \see cl_page_assume()
830 * \see vvp_page_assume(), lov_page_assume()
832 void (*cpo_assume)(const struct lu_env *env,
833 const struct cl_page_slice *slice, struct cl_io *io);
834 /** Dual to cl_page_operations::cpo_assume(). Optional. Called
835 * bottom-to-top when IO releases a page without actually unlocking
838 * \see cl_page_unassume()
839 * \see vvp_page_unassume()
841 void (*cpo_unassume)(const struct lu_env *env,
842 const struct cl_page_slice *slice,
845 * Announces whether the page contains valid data or not by \a uptodate.
847 * \see cl_page_export()
848 * \see vvp_page_export()
850 void (*cpo_export)(const struct lu_env *env,
851 const struct cl_page_slice *slice, int uptodate);
853 * Checks whether underlying VM page is locked (in the suitable
854 * sense). Used for assertions.
856 * \retval -EBUSY: page is protected by a lock of a given mode;
857 * \retval -ENODATA: page is not protected by a lock;
858 * \retval 0: this layer cannot decide. (Should never happen.)
860 int (*cpo_is_vmlocked)(const struct lu_env *env,
861 const struct cl_page_slice *slice);
867 * Called when page is truncated from the object. Optional.
869 * \see cl_page_discard()
870 * \see vvp_page_discard(), osc_page_discard()
872 void (*cpo_discard)(const struct lu_env *env,
873 const struct cl_page_slice *slice,
876 * Called when page is removed from the cache, and is about to being
877 * destroyed. Optional.
879 * \see cl_page_delete()
880 * \see vvp_page_delete(), osc_page_delete()
882 void (*cpo_delete)(const struct lu_env *env,
883 const struct cl_page_slice *slice);
884 /** Destructor. Frees resources and slice itself. */
885 void (*cpo_fini)(const struct lu_env *env,
886 struct cl_page_slice *slice);
888 * Optional debugging helper. Prints given page slice.
890 * \see cl_page_print()
892 int (*cpo_print)(const struct lu_env *env,
893 const struct cl_page_slice *slice,
894 void *cookie, lu_printer_t p);
903 * Request type dependent vector of operations.
905 * Transfer operations depend on transfer mode (cl_req_type). To avoid
906 * passing transfer mode to each and every of these methods, and to
907 * avoid branching on request type inside of the methods, separate
908 * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
909 * provided. That is, method invocation usually looks like
911 * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
915 * Called when a page is submitted for a transfer as a part of
918 * \return 0 : page is eligible for submission;
919 * \return -EALREADY : skip this page;
920 * \return -ve : error.
922 * \see cl_page_prep()
924 int (*cpo_prep)(const struct lu_env *env,
925 const struct cl_page_slice *slice,
928 * Completion handler. This is guaranteed to be eventually
929 * fired after cl_page_operations::cpo_prep() or
930 * cl_page_operations::cpo_make_ready() call.
932 * This method can be called in a non-blocking context. It is
933 * guaranteed however, that the page involved and its object
934 * are pinned in memory (and, hence, calling cl_page_put() is
937 * \see cl_page_completion()
939 void (*cpo_completion)(const struct lu_env *env,
940 const struct cl_page_slice *slice,
943 * Called when cached page is about to be added to the
944 * ptlrpc request as a part of req formation.
946 * \return 0 : proceed with this page;
947 * \return -EAGAIN : skip this page;
948 * \return -ve : error.
950 * \see cl_page_make_ready()
952 int (*cpo_make_ready)(const struct lu_env *env,
953 const struct cl_page_slice *slice);
956 * Tell transfer engine that only [to, from] part of a page should be
959 * This is used for immediate transfers.
961 * \todo XXX this is not very good interface. It would be much better
962 * if all transfer parameters were supplied as arguments to
963 * cl_io_operations::cio_submit() call, but it is not clear how to do
964 * this for page queues.
966 * \see cl_page_clip()
968 void (*cpo_clip)(const struct lu_env *env,
969 const struct cl_page_slice *slice,
972 * \pre the page was queued for transferring.
973 * \post page is removed from client's pending list, or -EBUSY
974 * is returned if it has already been in transferring.
976 * This is one of seldom page operation which is:
977 * 0. called from top level;
978 * 1. don't have vmpage locked;
979 * 2. every layer should synchronize execution of its ->cpo_cancel()
980 * with completion handlers. Osc uses client obd lock for this
981 * purpose. Based on there is no vvp_page_cancel and
982 * lov_page_cancel(), cpo_cancel is defacto protected by client lock.
984 * \see osc_page_cancel().
986 int (*cpo_cancel)(const struct lu_env *env,
987 const struct cl_page_slice *slice);
989 * Write out a page by kernel. This is only called by ll_writepage
992 * \see cl_page_flush()
994 int (*cpo_flush)(const struct lu_env *env,
995 const struct cl_page_slice *slice,
1001 * Helper macro, dumping detailed information about \a page into a log.
1003 #define CL_PAGE_DEBUG(mask, env, page, format, ...) \
1005 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1006 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1007 cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
1008 CDEBUG(mask, format , ## __VA_ARGS__); \
1013 * Helper macro, dumping shorter information about \a page into a log.
1015 #define CL_PAGE_HEADER(mask, env, page, format, ...) \
1017 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1018 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1019 cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
1020 CDEBUG(mask, format , ## __VA_ARGS__); \
1024 static inline struct page *cl_page_vmpage(const struct cl_page *page)
1026 LASSERT(page->cp_vmpage != NULL);
1027 return page->cp_vmpage;
1031 * Check if a cl_page is in use.
1033 * Client cache holds a refcount, this refcount will be dropped when
1034 * the page is taken out of cache, see vvp_page_delete().
1036 static inline bool __page_in_use(const struct cl_page *page, int refc)
1038 return (atomic_read(&page->cp_ref) > refc + 1);
1042 * Caller itself holds a refcount of cl_page.
1044 #define cl_page_in_use(pg) __page_in_use(pg, 1)
1046 * Caller doesn't hold a refcount.
1048 #define cl_page_in_use_noref(pg) __page_in_use(pg, 0)
1052 /** \addtogroup cl_lock cl_lock
1056 * Extent locking on the client.
1060 * The locking model of the new client code is built around
1064 * data-type representing an extent lock on a regular file. cl_lock is a
1065 * layered object (much like cl_object and cl_page), it consists of a header
1066 * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
1067 * cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
1069 * Typical cl_lock consists of the two layers:
1071 * - vvp_lock (vvp specific data), and
1072 * - lov_lock (lov specific data).
1074 * lov_lock contains an array of sub-locks. Each of these sub-locks is a
1075 * normal cl_lock: it has a header (struct cl_lock) and a list of layers:
1077 * - lovsub_lock, and
1080 * Each sub-lock is associated with a cl_object (representing stripe
1081 * sub-object or the file to which top-level cl_lock is associated to), and is
1082 * linked into that cl_object::coh_locks. In this respect cl_lock is similar to
1083 * cl_object (that at lov layer also fans out into multiple sub-objects), and
1084 * is different from cl_page, that doesn't fan out (there is usually exactly
1085 * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
1086 * a "top-lock" and its lovsub-osc portion a "sub-lock".
1090 * cl_lock is a cacheless data container for the requirements of locks to
1091 * complete the IO. cl_lock is created before I/O starts and destroyed when the
1094 * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
1095 * to cl_lock at OSC layer. LDLM lock is still cacheable.
1097 * INTERFACE AND USAGE
1099 * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
1100 * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
1101 * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
1102 * consists of multiple sub cl_locks, each sub locks will be enqueued
1103 * correspondingly. At OSC layer, the lock enqueue request will tend to reuse
1104 * cached LDLM lock; otherwise a new LDLM lock will have to be requested from
1107 * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
1108 * method will be called for each layer to release the resource held by this
1109 * lock. At OSC layer, the reference count of LDLM lock, which is held at
1110 * clo_enqueue time, is released.
1112 * LDLM lock can only be canceled if there is no cl_lock using it.
1114 * Overall process of the locking during IO operation is as following:
1116 * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
1117 * is called on each layer. Responsibility of this method is to add locks,
1118 * needed by a given layer into cl_io.ci_lockset.
1120 * - once locks for all layers were collected, they are sorted to avoid
1121 * dead-locks (cl_io_locks_sort()), and enqueued.
1123 * - when all locks are acquired, IO is performed;
1125 * - locks are released after IO is complete.
1127 * Striping introduces major additional complexity into locking. The
1128 * fundamental problem is that it is generally unsafe to actively use (hold)
1129 * two locks on the different OST servers at the same time, as this introduces
1130 * inter-server dependency and can lead to cascading evictions.
1132 * Basic solution is to sub-divide large read/write IOs into smaller pieces so
1133 * that no multi-stripe locks are taken (note that this design abandons POSIX
1134 * read/write semantics). Such pieces ideally can be executed concurrently. At
1135 * the same time, certain types of IO cannot be sub-divived, without
1136 * sacrificing correctness. This includes:
1138 * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
1141 * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
1143 * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
1144 * buf is a part of memory mapped Lustre file, a lock or locks protecting buf
1145 * has to be held together with the usual lock on [offset, offset + count].
1147 * Interaction with DLM
1149 * In the expected setup, cl_lock is ultimately backed up by a collection of
1150 * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
1151 * implemented in osc layer, that also matches DLM events (ASTs, cancellation,
1152 * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
1153 * description of interaction with DLM.
1159 struct cl_lock_descr {
1160 /** Object this lock is granted for. */
1161 struct cl_object *cld_obj;
1162 /** Index of the first page protected by this lock. */
1164 /** Index of the last page (inclusive) protected by this lock. */
1166 /** Group ID, for group lock */
1169 enum cl_lock_mode cld_mode;
1171 * flags to enqueue lock. A combination of bit-flags from
1172 * enum cl_enq_flags.
1174 __u32 cld_enq_flags;
1177 #define DDESCR "%s(%d):[%lu, %lu]:%x"
1178 #define PDESCR(descr) \
1179 cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
1180 (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
1182 const char *cl_lock_mode_name(const enum cl_lock_mode mode);
1185 * Layered client lock.
1188 /** List of slices. Immutable after creation. */
1189 struct list_head cll_layers;
1190 /** lock attribute, extent, cl_object, etc. */
1191 struct cl_lock_descr cll_descr;
1195 * Per-layer part of cl_lock
1197 * \see vvp_lock, lov_lock, lovsub_lock, osc_lock
1199 struct cl_lock_slice {
1200 struct cl_lock *cls_lock;
1201 /** Object slice corresponding to this lock slice. Immutable after
1203 struct cl_object *cls_obj;
1204 const struct cl_lock_operations *cls_ops;
1205 /** Linkage into cl_lock::cll_layers. Immutable after creation. */
1206 struct list_head cls_linkage;
1211 * \see vvp_lock_ops, lov_lock_ops, lovsub_lock_ops, osc_lock_ops
1213 struct cl_lock_operations {
1216 * Attempts to enqueue the lock. Called top-to-bottom.
1218 * \retval 0 this layer has enqueued the lock successfully
1219 * \retval >0 this layer has enqueued the lock, but need to wait on
1220 * @anchor for resources
1221 * \retval -ve failure
1223 * \see vvp_lock_enqueue(), lov_lock_enqueue(), lovsub_lock_enqueue(),
1224 * \see osc_lock_enqueue()
1226 int (*clo_enqueue)(const struct lu_env *env,
1227 const struct cl_lock_slice *slice,
1228 struct cl_io *io, struct cl_sync_io *anchor);
1230 * Cancel a lock, release its DLM lock ref, while does not cancel the
1233 void (*clo_cancel)(const struct lu_env *env,
1234 const struct cl_lock_slice *slice);
1237 * Destructor. Frees resources and the slice.
1239 * \see vvp_lock_fini(), lov_lock_fini(), lovsub_lock_fini(),
1240 * \see osc_lock_fini()
1242 void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
1244 * Optional debugging helper. Prints given lock slice.
1246 int (*clo_print)(const struct lu_env *env,
1247 void *cookie, lu_printer_t p,
1248 const struct cl_lock_slice *slice);
1251 #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
1253 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1254 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1255 cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
1256 CDEBUG(mask, format , ## __VA_ARGS__); \
1260 #define CL_LOCK_ASSERT(expr, env, lock) do { \
1264 CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
1270 /** \addtogroup cl_page_list cl_page_list
1271 * Page list used to perform collective operations on a group of pages.
1273 * Pages are added to the list one by one. cl_page_list acquires a reference
1274 * for every page in it. Page list is used to perform collective operations on
1277 * - submit pages for an immediate transfer,
1279 * - own pages on behalf of certain io (waiting for each page in turn),
1283 * When list is finalized, it releases references on all pages it still has.
1285 * \todo XXX concurrency control.
1289 struct cl_page_list {
1291 struct list_head pl_pages;
1292 struct task_struct *pl_owner;
1296 * A 2-queue of pages. A convenience data-type for common use case, 2-queue
1297 * contains an incoming page list and an outgoing page list.
1300 struct cl_page_list c2_qin;
1301 struct cl_page_list c2_qout;
1304 /** @} cl_page_list */
1306 /** \addtogroup cl_io cl_io
1311 * cl_io represents a high level I/O activity like
1312 * read(2)/write(2)/truncate(2) system call, or cancellation of an extent
1315 * cl_io is a layered object, much like cl_{object,page,lock} but with one
1316 * important distinction. We want to minimize number of calls to the allocator
1317 * in the fast path, e.g., in the case of read(2) when everything is cached:
1318 * client already owns the lock over region being read, and data are cached
1319 * due to read-ahead. To avoid allocation of cl_io layers in such situations,
1320 * per-layer io state is stored in the session, associated with the io, see
1321 * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
1322 * by using free-lists, see cl_env_get().
1324 * There is a small predefined number of possible io types, enumerated in enum
1327 * cl_io is a state machine, that can be advanced concurrently by the multiple
1328 * threads. It is up to these threads to control the concurrency and,
1329 * specifically, to detect when io is done, and its state can be safely
1332 * For read/write io overall execution plan is as following:
1334 * (0) initialize io state through all layers;
1336 * (1) loop: prepare chunk of work to do
1338 * (2) call all layers to collect locks they need to process current chunk
1340 * (3) sort all locks to avoid dead-locks, and acquire them
1342 * (4) process the chunk: call per-page methods
1343 * cl_io_operations::cio_prepare_write(),
1344 * cl_io_operations::cio_commit_write() for write)
1350 * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
1351 * address allocation efficiency issues mentioned above), and returns with the
1352 * special error condition from per-page method when current sub-io has to
1353 * block. This causes io loop to be repeated, and lov switches to the next
1354 * sub-io in its cl_io_operations::cio_iter_init() implementation.
1359 /** read system call */
1361 /** write system call */
1363 /** truncate, utime system calls */
1365 /** get data version */
1368 * page fault handling
1372 * fsync system call handling
1373 * To write out a range of file
1377 * Miscellaneous io. This is used for occasional io activity that
1378 * doesn't fit into other types. Currently this is used for:
1380 * - cancellation of an extent lock. This io exists as a context
1381 * to write dirty pages from under the lock being canceled back
1384 * - VM induced page write-out. An io context for writing page out
1385 * for memory cleansing;
1387 * - glimpse. An io context to acquire glimpse lock.
1389 * - grouplock. An io context to acquire group lock.
1391 * CIT_MISC io is used simply as a context in which locks and pages
1392 * are manipulated. Such io has no internal "process", that is,
1393 * cl_io_loop() is never called for it.
1398 * To give advice about access of a file
1405 * States of cl_io state machine
1408 /** Not initialized. */
1412 /** IO iteration started. */
1416 /** Actual IO is in progress. */
1418 /** IO for the current iteration finished. */
1420 /** Locks released. */
1422 /** Iteration completed. */
1424 /** cl_io finalized. */
1429 * IO state private for a layer.
1431 * This is usually embedded into layer session data, rather than allocated
1434 * \see vvp_io, lov_io, osc_io
1436 struct cl_io_slice {
1437 struct cl_io *cis_io;
1438 /** corresponding object slice. Immutable after creation. */
1439 struct cl_object *cis_obj;
1440 /** io operations. Immutable after creation. */
1441 const struct cl_io_operations *cis_iop;
1443 * linkage into a list of all slices for a given cl_io, hanging off
1444 * cl_io::ci_layers. Immutable after creation.
1446 struct list_head cis_linkage;
1449 typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
1452 struct cl_read_ahead {
1453 /* Maximum page index the readahead window will end.
1454 * This is determined DLM lock coverage, RPC and stripe boundary.
1455 * cra_end is included. */
1457 /* optimal RPC size for this read, by pages */
1458 unsigned long cra_rpc_size;
1459 /* Release callback. If readahead holds resources underneath, this
1460 * function should be called to release it. */
1461 void (*cra_release)(const struct lu_env *env, void *cbdata);
1462 /* Callback data for cra_release routine */
1466 static inline void cl_read_ahead_release(const struct lu_env *env,
1467 struct cl_read_ahead *ra)
1469 if (ra->cra_release != NULL)
1470 ra->cra_release(env, ra->cra_cbdata);
1471 memset(ra, 0, sizeof(*ra));
1476 * Per-layer io operations.
1477 * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
1479 struct cl_io_operations {
1481 * Vector of io state transition methods for every io type.
1483 * \see cl_page_operations::io
1487 * Prepare io iteration at a given layer.
1489 * Called top-to-bottom at the beginning of each iteration of
1490 * "io loop" (if it makes sense for this type of io). Here
1491 * layer selects what work it will do during this iteration.
1493 * \see cl_io_operations::cio_iter_fini()
1495 int (*cio_iter_init) (const struct lu_env *env,
1496 const struct cl_io_slice *slice);
1498 * Finalize io iteration.
1500 * Called bottom-to-top at the end of each iteration of "io
1501 * loop". Here layers can decide whether IO has to be
1504 * \see cl_io_operations::cio_iter_init()
1506 void (*cio_iter_fini) (const struct lu_env *env,
1507 const struct cl_io_slice *slice);
1509 * Collect locks for the current iteration of io.
1511 * Called top-to-bottom to collect all locks necessary for
1512 * this iteration. This methods shouldn't actually enqueue
1513 * anything, instead it should post a lock through
1514 * cl_io_lock_add(). Once all locks are collected, they are
1515 * sorted and enqueued in the proper order.
1517 int (*cio_lock) (const struct lu_env *env,
1518 const struct cl_io_slice *slice);
1520 * Finalize unlocking.
1522 * Called bottom-to-top to finish layer specific unlocking
1523 * functionality, after generic code released all locks
1524 * acquired by cl_io_operations::cio_lock().
1526 void (*cio_unlock)(const struct lu_env *env,
1527 const struct cl_io_slice *slice);
1529 * Start io iteration.
1531 * Once all locks are acquired, called top-to-bottom to
1532 * commence actual IO. In the current implementation,
1533 * top-level vvp_io_{read,write}_start() does all the work
1534 * synchronously by calling generic_file_*(), so other layers
1535 * are called when everything is done.
1537 int (*cio_start)(const struct lu_env *env,
1538 const struct cl_io_slice *slice);
1540 * Called top-to-bottom at the end of io loop. Here layer
1541 * might wait for an unfinished asynchronous io.
1543 void (*cio_end) (const struct lu_env *env,
1544 const struct cl_io_slice *slice);
1546 * Called bottom-to-top to notify layers that read/write IO
1547 * iteration finished, with \a nob bytes transferred.
1549 void (*cio_advance)(const struct lu_env *env,
1550 const struct cl_io_slice *slice,
1553 * Called once per io, bottom-to-top to release io resources.
1555 void (*cio_fini) (const struct lu_env *env,
1556 const struct cl_io_slice *slice);
1560 * Submit pages from \a queue->c2_qin for IO, and move
1561 * successfully submitted pages into \a queue->c2_qout. Return
1562 * non-zero if failed to submit even the single page. If
1563 * submission failed after some pages were moved into \a
1564 * queue->c2_qout, completion callback with non-zero ioret is
1567 int (*cio_submit)(const struct lu_env *env,
1568 const struct cl_io_slice *slice,
1569 enum cl_req_type crt,
1570 struct cl_2queue *queue);
1572 * Queue async page for write.
1573 * The difference between cio_submit and cio_queue is that
1574 * cio_submit is for urgent request.
1576 int (*cio_commit_async)(const struct lu_env *env,
1577 const struct cl_io_slice *slice,
1578 struct cl_page_list *queue, int from, int to,
1581 * Decide maximum read ahead extent
1583 * \pre io->ci_type == CIT_READ
1585 int (*cio_read_ahead)(const struct lu_env *env,
1586 const struct cl_io_slice *slice,
1587 pgoff_t start, struct cl_read_ahead *ra);
1589 * Optional debugging helper. Print given io slice.
1591 int (*cio_print)(const struct lu_env *env, void *cookie,
1592 lu_printer_t p, const struct cl_io_slice *slice);
1596 * Flags to lock enqueue procedure.
1601 * instruct server to not block, if conflicting lock is found. Instead
1602 * -EWOULDBLOCK is returned immediately.
1604 CEF_NONBLOCK = 0x00000001,
1606 * take lock asynchronously (out of order), as it cannot
1607 * deadlock. This is for LDLM_FL_HAS_INTENT locks used for glimpsing.
1609 CEF_ASYNC = 0x00000002,
1611 * tell the server to instruct (though a flag in the blocking ast) an
1612 * owner of the conflicting lock, that it can drop dirty pages
1613 * protected by this lock, without sending them to the server.
1615 CEF_DISCARD_DATA = 0x00000004,
1617 * tell the sub layers that it must be a `real' lock. This is used for
1618 * mmapped-buffer locks and glimpse locks that must be never converted
1619 * into lockless mode.
1621 * \see vvp_mmap_locks(), cl_glimpse_lock().
1623 CEF_MUST = 0x00000008,
1625 * tell the sub layers that never request a `real' lock. This flag is
1626 * not used currently.
1628 * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
1629 * conversion policy: ci_lockreq describes generic information of lock
1630 * requirement for this IO, especially for locks which belong to the
1631 * object doing IO; however, lock itself may have precise requirements
1632 * that are described by the enqueue flags.
1634 CEF_NEVER = 0x00000010,
1636 * for async glimpse lock.
1638 CEF_AGL = 0x00000020,
1640 * enqueue a lock to test DLM lock existence.
1642 CEF_PEEK = 0x00000040,
1644 * Lock match only. Used by group lock in I/O as group lock
1645 * is known to exist.
1647 CEF_LOCK_MATCH = 0x00000080,
1649 * mask of enq_flags.
1651 CEF_MASK = 0x000000ff,
1655 * Link between lock and io. Intermediate structure is needed, because the
1656 * same lock can be part of multiple io's simultaneously.
1658 struct cl_io_lock_link {
1659 /** linkage into one of cl_lockset lists. */
1660 struct list_head cill_linkage;
1661 struct cl_lock cill_lock;
1662 /** optional destructor */
1663 void (*cill_fini)(const struct lu_env *env,
1664 struct cl_io_lock_link *link);
1666 #define cill_descr cill_lock.cll_descr
1669 * Lock-set represents a collection of locks, that io needs at a
1670 * time. Generally speaking, client tries to avoid holding multiple locks when
1673 * - holding extent locks over multiple ost's introduces the danger of
1674 * "cascading timeouts";
1676 * - holding multiple locks over the same ost is still dead-lock prone,
1677 * see comment in osc_lock_enqueue(),
1679 * but there are certain situations where this is unavoidable:
1681 * - O_APPEND writes have to take [0, EOF] lock for correctness;
1683 * - truncate has to take [new-size, EOF] lock for correctness;
1685 * - SNS has to take locks across full stripe for correctness;
1687 * - in the case when user level buffer, supplied to {read,write}(file0),
1688 * is a part of a memory mapped lustre file, client has to take a dlm
1689 * locks on file0, and all files that back up the buffer (or a part of
1690 * the buffer, that is being processed in the current chunk, in any
1691 * case, there are situations where at least 2 locks are necessary).
1693 * In such cases we at least try to take locks in the same consistent
1694 * order. To this end, all locks are first collected, then sorted, and then
1698 /** locks to be acquired. */
1699 struct list_head cls_todo;
1700 /** locks acquired. */
1701 struct list_head cls_done;
1705 * Lock requirements(demand) for IO. It should be cl_io_lock_req,
1706 * but 'req' is always to be thought as 'request' :-)
1708 enum cl_io_lock_dmd {
1709 /** Always lock data (e.g., O_APPEND). */
1711 /** Layers are free to decide between local and global locking. */
1713 /** Never lock: there is no cache (e.g., liblustre). */
1717 enum cl_fsync_mode {
1718 /** start writeback, do not wait for them to finish */
1720 /** start writeback and wait for them to finish */
1722 /** discard all of dirty pages in a specific file range */
1723 CL_FSYNC_DISCARD = 2,
1724 /** start writeback and make sure they have reached storage before
1725 * return. OST_SYNC RPC must be issued and finished */
1729 struct cl_io_rw_common {
1738 * cl_io is shared by all threads participating in this IO (in current
1739 * implementation only one thread advances IO, but parallel IO design and
1740 * concurrent copy_*_user() require multiple threads acting on the same IO. It
1741 * is up to these threads to serialize their activities, including updates to
1742 * mutable cl_io fields.
1745 /** type of this IO. Immutable after creation. */
1746 enum cl_io_type ci_type;
1747 /** current state of cl_io state machine. */
1748 enum cl_io_state ci_state;
1749 /** main object this io is against. Immutable after creation. */
1750 struct cl_object *ci_obj;
1752 * Upper layer io, of which this io is a part of. Immutable after
1755 struct cl_io *ci_parent;
1756 /** List of slices. Immutable after creation. */
1757 struct list_head ci_layers;
1758 /** list of locks (to be) acquired by this io. */
1759 struct cl_lockset ci_lockset;
1760 /** lock requirements, this is just a help info for sublayers. */
1761 enum cl_io_lock_dmd ci_lockreq;
1764 struct cl_io_rw_common rd;
1767 struct cl_io_rw_common wr;
1771 struct cl_io_rw_common ci_rw;
1772 struct cl_setattr_io {
1773 struct ost_lvb sa_attr;
1774 unsigned int sa_attr_flags;
1775 unsigned int sa_valid;
1776 int sa_stripe_index;
1777 const struct lu_fid *sa_parent_fid;
1779 struct cl_data_version_io {
1780 u64 dv_data_version;
1783 struct cl_fault_io {
1784 /** page index within file. */
1786 /** bytes valid byte on a faulted page. */
1788 /** writable page? for nopage() only */
1790 /** page of an executable? */
1792 /** page_mkwrite() */
1794 /** resulting page */
1795 struct cl_page *ft_page;
1797 struct cl_fsync_io {
1800 /** file system level fid */
1801 struct lu_fid *fi_fid;
1802 enum cl_fsync_mode fi_mode;
1803 /* how many pages were written/discarded */
1804 unsigned int fi_nr_written;
1806 struct cl_ladvise_io {
1809 /** file system level fid */
1810 struct lu_fid *li_fid;
1811 enum lu_ladvise_type li_advice;
1815 struct cl_2queue ci_queue;
1818 unsigned int ci_continue:1,
1820 * This io has held grouplock, to inform sublayers that
1821 * don't do lockless i/o.
1825 * The whole IO need to be restarted because layout has been changed
1829 * to not refresh layout - the IO issuer knows that the layout won't
1830 * change(page operations, layout change causes all page to be
1831 * discarded), or it doesn't matter if it changes(sync).
1835 * Check if layout changed after the IO finishes. Mainly for HSM
1836 * requirement. If IO occurs to openning files, it doesn't need to
1837 * verify layout because HSM won't release openning files.
1838 * Right now, only two opertaions need to verify layout: glimpse
1843 * file is released, restore has to to be triggered by vvp layer
1845 ci_restore_needed:1,
1851 * Number of pages owned by this IO. For invariant checking.
1853 unsigned ci_owned_nr;
1859 * Per-transfer attributes.
1861 struct cl_req_attr {
1862 enum cl_req_type cra_type;
1864 struct cl_page *cra_page;
1865 /** Generic attributes for the server consumption. */
1866 struct obdo *cra_oa;
1868 char cra_jobid[LUSTRE_JOBID_SIZE];
1871 enum cache_stats_item {
1872 /** how many cache lookups were performed */
1874 /** how many times cache lookup resulted in a hit */
1876 /** how many entities are in the cache right now */
1878 /** how many entities in the cache are actively used (and cannot be
1879 * evicted) right now */
1881 /** how many entities were created at all */
1886 #define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
1889 * Stats for a generic cache (similar to inode, lu_object, etc. caches).
1891 struct cache_stats {
1892 const char *cs_name;
1893 atomic_t cs_stats[CS_NR];
1896 /** These are not exported so far */
1897 void cache_stats_init (struct cache_stats *cs, const char *name);
1900 * Client-side site. This represents particular client stack. "Global"
1901 * variables should (directly or indirectly) be added here to allow multiple
1902 * clients to co-exist in the single address space.
1905 struct lu_site cs_lu;
1907 * Statistical counters. Atomics do not scale, something better like
1908 * per-cpu counters is needed.
1910 * These are exported as /proc/fs/lustre/llite/.../site
1912 * When interpreting keep in mind that both sub-locks (and sub-pages)
1913 * and top-locks (and top-pages) are accounted here.
1915 struct cache_stats cs_pages;
1916 atomic_t cs_pages_state[CPS_NR];
1919 int cl_site_init(struct cl_site *s, struct cl_device *top);
1920 void cl_site_fini(struct cl_site *s);
1921 void cl_stack_fini(const struct lu_env *env, struct cl_device *cl);
1924 * Output client site statistical counters into a buffer. Suitable for
1925 * ll_rd_*()-style functions.
1927 int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
1932 * Type conversion and accessory functions.
1936 static inline struct cl_site *lu2cl_site(const struct lu_site *site)
1938 return container_of(site, struct cl_site, cs_lu);
1941 static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
1943 LASSERT(d == NULL || IS_ERR(d) || lu_device_is_cl(d));
1944 return container_of0(d, struct cl_device, cd_lu_dev);
1947 static inline struct lu_device *cl2lu_dev(struct cl_device *d)
1949 return &d->cd_lu_dev;
1952 static inline struct cl_object *lu2cl(const struct lu_object *o)
1954 LASSERT(o == NULL || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
1955 return container_of0(o, struct cl_object, co_lu);
1958 static inline const struct cl_object_conf *
1959 lu2cl_conf(const struct lu_object_conf *conf)
1961 return container_of0(conf, struct cl_object_conf, coc_lu);
1964 static inline struct cl_object *cl_object_next(const struct cl_object *obj)
1966 return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL;
1969 static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
1971 return container_of0(h, struct cl_object_header, coh_lu);
1974 static inline struct cl_site *cl_object_site(const struct cl_object *obj)
1976 return lu2cl_site(obj->co_lu.lo_dev->ld_site);
1980 struct cl_object_header *cl_object_header(const struct cl_object *obj)
1982 return luh2coh(obj->co_lu.lo_header);
1985 static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
1987 return lu_device_init(&d->cd_lu_dev, t);
1990 static inline void cl_device_fini(struct cl_device *d)
1992 lu_device_fini(&d->cd_lu_dev);
1995 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
1996 struct cl_object *obj, pgoff_t index,
1997 const struct cl_page_operations *ops);
1998 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
1999 struct cl_object *obj,
2000 const struct cl_lock_operations *ops);
2001 void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
2002 struct cl_object *obj, const struct cl_io_operations *ops);
2005 /** \defgroup cl_object cl_object
2007 struct cl_object *cl_object_top (struct cl_object *o);
2008 struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
2009 const struct lu_fid *fid,
2010 const struct cl_object_conf *c);
2012 int cl_object_header_init(struct cl_object_header *h);
2013 void cl_object_header_fini(struct cl_object_header *h);
2014 void cl_object_put (const struct lu_env *env, struct cl_object *o);
2015 void cl_object_get (struct cl_object *o);
2016 void cl_object_attr_lock (struct cl_object *o);
2017 void cl_object_attr_unlock(struct cl_object *o);
2018 int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
2019 struct cl_attr *attr);
2020 int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
2021 const struct cl_attr *attr, unsigned valid);
2022 int cl_object_glimpse (const struct lu_env *env, struct cl_object *obj,
2023 struct ost_lvb *lvb);
2024 int cl_conf_set (const struct lu_env *env, struct cl_object *obj,
2025 const struct cl_object_conf *conf);
2026 int cl_object_prune (const struct lu_env *env, struct cl_object *obj);
2027 void cl_object_kill (const struct lu_env *env, struct cl_object *obj);
2028 int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj,
2029 struct lov_user_md __user *lum);
2030 int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj,
2031 struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap,
2033 int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj,
2034 struct cl_layout *cl);
2035 loff_t cl_object_maxbytes(struct cl_object *obj);
2038 * Returns true, iff \a o0 and \a o1 are slices of the same object.
2040 static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
2042 return cl_object_header(o0) == cl_object_header(o1);
2045 static inline void cl_object_page_init(struct cl_object *clob, int size)
2047 clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
2048 cl_object_header(clob)->coh_page_bufsize += cfs_size_round(size);
2049 WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
2052 static inline void *cl_object_page_slice(struct cl_object *clob,
2053 struct cl_page *page)
2055 return (void *)((char *)page + clob->co_slice_off);
2059 * Return refcount of cl_object.
2061 static inline int cl_object_refc(struct cl_object *clob)
2063 struct lu_object_header *header = clob->co_lu.lo_header;
2064 return atomic_read(&header->loh_ref);
2069 /** \defgroup cl_page cl_page
2077 /* callback of cl_page_gang_lookup() */
2079 struct cl_page *cl_page_find (const struct lu_env *env,
2080 struct cl_object *obj,
2081 pgoff_t idx, struct page *vmpage,
2082 enum cl_page_type type);
2083 struct cl_page *cl_page_alloc (const struct lu_env *env,
2084 struct cl_object *o, pgoff_t ind,
2085 struct page *vmpage,
2086 enum cl_page_type type);
2087 void cl_page_get (struct cl_page *page);
2088 void cl_page_put (const struct lu_env *env,
2089 struct cl_page *page);
2090 void cl_page_print (const struct lu_env *env, void *cookie,
2091 lu_printer_t printer,
2092 const struct cl_page *pg);
2093 void cl_page_header_print(const struct lu_env *env, void *cookie,
2094 lu_printer_t printer,
2095 const struct cl_page *pg);
2096 struct cl_page *cl_vmpage_page (struct page *vmpage, struct cl_object *obj);
2097 struct cl_page *cl_page_top (struct cl_page *page);
2099 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
2100 const struct lu_device_type *dtype);
2105 * Functions dealing with the ownership of page by io.
2109 int cl_page_own (const struct lu_env *env,
2110 struct cl_io *io, struct cl_page *page);
2111 int cl_page_own_try (const struct lu_env *env,
2112 struct cl_io *io, struct cl_page *page);
2113 void cl_page_assume (const struct lu_env *env,
2114 struct cl_io *io, struct cl_page *page);
2115 void cl_page_unassume (const struct lu_env *env,
2116 struct cl_io *io, struct cl_page *pg);
2117 void cl_page_disown (const struct lu_env *env,
2118 struct cl_io *io, struct cl_page *page);
2119 int cl_page_is_owned (const struct cl_page *pg, const struct cl_io *io);
2126 * Functions dealing with the preparation of a page for a transfer, and
2127 * tracking transfer state.
2130 int cl_page_prep (const struct lu_env *env, struct cl_io *io,
2131 struct cl_page *pg, enum cl_req_type crt);
2132 void cl_page_completion (const struct lu_env *env,
2133 struct cl_page *pg, enum cl_req_type crt, int ioret);
2134 int cl_page_make_ready (const struct lu_env *env, struct cl_page *pg,
2135 enum cl_req_type crt);
2136 int cl_page_cache_add (const struct lu_env *env, struct cl_io *io,
2137 struct cl_page *pg, enum cl_req_type crt);
2138 void cl_page_clip (const struct lu_env *env, struct cl_page *pg,
2140 int cl_page_cancel (const struct lu_env *env, struct cl_page *page);
2141 int cl_page_flush (const struct lu_env *env, struct cl_io *io,
2142 struct cl_page *pg);
2148 * \name helper routines
2149 * Functions to discard, delete and export a cl_page.
2152 void cl_page_discard(const struct lu_env *env, struct cl_io *io,
2153 struct cl_page *pg);
2154 void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
2155 int cl_page_is_vmlocked(const struct lu_env *env,
2156 const struct cl_page *pg);
2157 void cl_page_export(const struct lu_env *env,
2158 struct cl_page *pg, int uptodate);
2159 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx);
2160 pgoff_t cl_index(const struct cl_object *obj, loff_t offset);
2161 size_t cl_page_size(const struct cl_object *obj);
2163 void cl_lock_print(const struct lu_env *env, void *cookie,
2164 lu_printer_t printer, const struct cl_lock *lock);
2165 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2166 lu_printer_t printer,
2167 const struct cl_lock_descr *descr);
2171 * Data structure managing a client's cached pages. A count of
2172 * "unstable" pages is maintained, and an LRU of clean pages is
2173 * maintained. "unstable" pages are pages pinned by the ptlrpc
2174 * layer for recovery purposes.
2176 struct cl_client_cache {
2178 * # of client cache refcount
2179 * # of users (OSCs) + 2 (held by llite and lov)
2183 * # of threads are doing shrinking
2185 unsigned int ccc_lru_shrinkers;
2187 * # of LRU entries available
2189 atomic_long_t ccc_lru_left;
2191 * List of entities(OSCs) for this LRU cache
2193 struct list_head ccc_lru;
2195 * Max # of LRU entries
2197 unsigned long ccc_lru_max;
2199 * Lock to protect ccc_lru list
2201 spinlock_t ccc_lru_lock;
2203 * Set if unstable check is enabled
2205 unsigned int ccc_unstable_check:1;
2207 * # of unstable pages for this mount point
2209 atomic_long_t ccc_unstable_nr;
2211 * Waitq for awaiting unstable pages to reach zero.
2212 * Used at umounting time and signaled on BRW commit
2214 wait_queue_head_t ccc_unstable_waitq;
2217 * cl_cache functions
2219 struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
2220 void cl_cache_incref(struct cl_client_cache *cache);
2221 void cl_cache_decref(struct cl_client_cache *cache);
2225 /** \defgroup cl_lock cl_lock
2227 int cl_lock_request(const struct lu_env *env, struct cl_io *io,
2228 struct cl_lock *lock);
2229 int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
2230 const struct cl_io *io);
2231 void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
2232 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
2233 const struct lu_device_type *dtype);
2234 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
2236 int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
2237 struct cl_lock *lock, struct cl_sync_io *anchor);
2238 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
2242 /** \defgroup cl_io cl_io
2245 int cl_io_init (const struct lu_env *env, struct cl_io *io,
2246 enum cl_io_type iot, struct cl_object *obj);
2247 int cl_io_sub_init (const struct lu_env *env, struct cl_io *io,
2248 enum cl_io_type iot, struct cl_object *obj);
2249 int cl_io_rw_init (const struct lu_env *env, struct cl_io *io,
2250 enum cl_io_type iot, loff_t pos, size_t count);
2251 int cl_io_loop (const struct lu_env *env, struct cl_io *io);
2253 void cl_io_fini (const struct lu_env *env, struct cl_io *io);
2254 int cl_io_iter_init (const struct lu_env *env, struct cl_io *io);
2255 void cl_io_iter_fini (const struct lu_env *env, struct cl_io *io);
2256 int cl_io_lock (const struct lu_env *env, struct cl_io *io);
2257 void cl_io_unlock (const struct lu_env *env, struct cl_io *io);
2258 int cl_io_start (const struct lu_env *env, struct cl_io *io);
2259 void cl_io_end (const struct lu_env *env, struct cl_io *io);
2260 int cl_io_lock_add (const struct lu_env *env, struct cl_io *io,
2261 struct cl_io_lock_link *link);
2262 int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
2263 struct cl_lock_descr *descr);
2264 int cl_io_submit_rw (const struct lu_env *env, struct cl_io *io,
2265 enum cl_req_type iot, struct cl_2queue *queue);
2266 int cl_io_submit_sync (const struct lu_env *env, struct cl_io *io,
2267 enum cl_req_type iot, struct cl_2queue *queue,
2269 int cl_io_commit_async (const struct lu_env *env, struct cl_io *io,
2270 struct cl_page_list *queue, int from, int to,
2272 int cl_io_read_ahead (const struct lu_env *env, struct cl_io *io,
2273 pgoff_t start, struct cl_read_ahead *ra);
2274 void cl_io_rw_advance (const struct lu_env *env, struct cl_io *io,
2276 int cl_io_cancel (const struct lu_env *env, struct cl_io *io,
2277 struct cl_page_list *queue);
2278 int cl_io_is_going (const struct lu_env *env);
2281 * True, iff \a io is an O_APPEND write(2).
2283 static inline int cl_io_is_append(const struct cl_io *io)
2285 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
2288 static inline int cl_io_is_sync_write(const struct cl_io *io)
2290 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
2293 static inline int cl_io_is_mkwrite(const struct cl_io *io)
2295 return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
2299 * True, iff \a io is a truncate(2).
2301 static inline int cl_io_is_trunc(const struct cl_io *io)
2303 return io->ci_type == CIT_SETATTR &&
2304 (io->u.ci_setattr.sa_valid & ATTR_SIZE);
2307 struct cl_io *cl_io_top(struct cl_io *io);
2309 void cl_io_print(const struct lu_env *env, void *cookie,
2310 lu_printer_t printer, const struct cl_io *io);
2312 #define CL_IO_SLICE_CLEAN(foo_io, base) \
2314 typeof(foo_io) __foo_io = (foo_io); \
2316 CLASSERT(offsetof(typeof(*__foo_io), base) == 0); \
2317 memset(&__foo_io->base + 1, 0, \
2318 (sizeof *__foo_io) - sizeof __foo_io->base); \
2323 /** \defgroup cl_page_list cl_page_list
2327 * Last page in the page list.
2329 static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
2331 LASSERT(plist->pl_nr > 0);
2332 return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
2335 static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
2337 LASSERT(plist->pl_nr > 0);
2338 return list_entry(plist->pl_pages.next, struct cl_page, cp_batch);
2342 * Iterate over pages in a page list.
2344 #define cl_page_list_for_each(page, list) \
2345 list_for_each_entry((page), &(list)->pl_pages, cp_batch)
2348 * Iterate over pages in a page list, taking possible removals into account.
2350 #define cl_page_list_for_each_safe(page, temp, list) \
2351 list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
2353 void cl_page_list_init (struct cl_page_list *plist);
2354 void cl_page_list_add (struct cl_page_list *plist, struct cl_page *page);
2355 void cl_page_list_move (struct cl_page_list *dst, struct cl_page_list *src,
2356 struct cl_page *page);
2357 void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
2358 struct cl_page *page);
2359 void cl_page_list_splice (struct cl_page_list *list,
2360 struct cl_page_list *head);
2361 void cl_page_list_del (const struct lu_env *env,
2362 struct cl_page_list *plist, struct cl_page *page);
2363 void cl_page_list_disown (const struct lu_env *env,
2364 struct cl_io *io, struct cl_page_list *plist);
2365 void cl_page_list_assume (const struct lu_env *env,
2366 struct cl_io *io, struct cl_page_list *plist);
2367 void cl_page_list_discard(const struct lu_env *env,
2368 struct cl_io *io, struct cl_page_list *plist);
2369 void cl_page_list_fini (const struct lu_env *env, struct cl_page_list *plist);
2371 void cl_2queue_init (struct cl_2queue *queue);
2372 void cl_2queue_add (struct cl_2queue *queue, struct cl_page *page);
2373 void cl_2queue_disown (const struct lu_env *env,
2374 struct cl_io *io, struct cl_2queue *queue);
2375 void cl_2queue_assume (const struct lu_env *env,
2376 struct cl_io *io, struct cl_2queue *queue);
2377 void cl_2queue_discard (const struct lu_env *env,
2378 struct cl_io *io, struct cl_2queue *queue);
2379 void cl_2queue_fini (const struct lu_env *env, struct cl_2queue *queue);
2380 void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
2382 /** @} cl_page_list */
2384 void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
2385 struct cl_req_attr *attr);
2387 /** \defgroup cl_sync_io cl_sync_io
2391 * Anchor for synchronous transfer. This is allocated on a stack by thread
2392 * doing synchronous transfer, and a pointer to this structure is set up in
2393 * every page submitted for transfer. Transfer completion routine updates
2394 * anchor and wakes up waiting thread when transfer is complete.
2397 /** number of pages yet to be transferred. */
2398 atomic_t csi_sync_nr;
2401 /** barrier of destroy this structure */
2402 atomic_t csi_barrier;
2403 /** completion to be signaled when transfer is complete. */
2404 wait_queue_head_t csi_waitq;
2405 /** callback to invoke when this IO is finished */
2406 void (*csi_end_io)(const struct lu_env *,
2407 struct cl_sync_io *);
2410 void cl_sync_io_init(struct cl_sync_io *anchor, int nr,
2411 void (*end)(const struct lu_env *, struct cl_sync_io *));
2412 int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
2414 void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
2416 void cl_sync_io_end(const struct lu_env *env, struct cl_sync_io *anchor);
2418 /** @} cl_sync_io */
2420 /** \defgroup cl_env cl_env
2422 * lu_env handling for a client.
2424 * lu_env is an environment within which lustre code executes. Its major part
2425 * is lu_context---a fast memory allocation mechanism that is used to conserve
2426 * precious kernel stack space. Originally lu_env was designed for a server,
2429 * - there is a (mostly) fixed number of threads, and
2431 * - call chains have no non-lustre portions inserted between lustre code.
2433 * On a client both these assumtpion fails, because every user thread can
2434 * potentially execute lustre code as part of a system call, and lustre calls
2435 * into VFS or MM that call back into lustre.
2437 * To deal with that, cl_env wrapper functions implement the following
2440 * - allocation and destruction of environment is amortized by caching no
2441 * longer used environments instead of destroying them;
2443 * \see lu_env, lu_context, lu_context_key
2446 struct lu_env *cl_env_get(__u16 *refcheck);
2447 struct lu_env *cl_env_alloc(__u16 *refcheck, __u32 tags);
2448 void cl_env_put(struct lu_env *env, __u16 *refcheck);
2449 unsigned cl_env_cache_purge(unsigned nr);
2450 struct lu_env *cl_env_percpu_get(void);
2451 void cl_env_percpu_put(struct lu_env *env);
2458 void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr);
2459 void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
2461 struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
2462 struct lu_device_type *ldt,
2463 struct lu_device *next);
2466 int cl_global_init(void);
2467 void cl_global_fini(void);
2469 #endif /* _LINUX_CL_OBJECT_H */