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29 * This file is part of Lustre, http://www.lustre.org/
31 #ifndef _LUSTRE_CL_OBJECT_H
32 #define _LUSTRE_CL_OBJECT_H
34 /** \defgroup clio clio
36 * Client objects implement io operations and cache pages.
38 * Examples: lov and osc are implementations of cl interface.
40 * Big Theory Statement.
44 * Client implementation is based on the following data-types:
50 * - cl_lock represents an extent lock on an object.
52 * - cl_io represents high-level i/o activity such as whole read/write
53 * system call, or write-out of pages from under the lock being
54 * canceled. cl_io has sub-ios that can be stopped and resumed
55 * independently, thus achieving high degree of transfer
56 * parallelism. Single cl_io can be advanced forward by
57 * the multiple threads (although in the most usual case of
58 * read/write system call it is associated with the single user
59 * thread, that issued the system call).
63 * - to avoid confusion high-level I/O operation like read or write system
64 * call is referred to as "an io", whereas low-level I/O operation, like
65 * RPC, is referred to as "a transfer"
67 * - "generic code" means generic (not file system specific) code in the
68 * hosting environment. "cl-code" means code (mostly in cl_*.c files) that
69 * is not layer specific.
75 * - cl_object_header::coh_page_guard
78 * See the top comment in cl_object.c for the description of overall locking and
79 * reference-counting design.
81 * See comments below for the description of i/o, page, and dlm-locking
88 * super-class definitions.
90 #include <linux/aio.h>
93 #include <libcfs/libcfs.h>
94 #include <lu_object.h>
95 #include <linux/atomic.h>
96 #include <linux/mutex.h>
97 #include <linux/radix-tree.h>
98 #include <linux/spinlock.h>
99 #include <linux/wait.h>
100 #include <linux/pagevec.h>
101 #include <lustre_dlm.h>
111 struct cl_page_slice;
113 struct cl_lock_slice;
115 struct cl_lock_operations;
116 struct cl_page_operations;
124 * Device in the client stack.
126 * \see vvp_device, lov_device, lovsub_device, osc_device
130 struct lu_device cd_lu_dev;
133 /** \addtogroup cl_object cl_object
136 * "Data attributes" of cl_object. Data attributes can be updated
137 * independently for a sub-object, and top-object's attributes are calculated
138 * from sub-objects' ones.
141 /** Object size, in bytes */
144 * Known minimal size, in bytes.
146 * This is only valid when at least one DLM lock is held.
149 /** Modification time. Measured in seconds since epoch. */
151 /** Access time. Measured in seconds since epoch. */
153 /** Change time. Measured in seconds since epoch. */
156 * Blocks allocated to this cl_object on the server file system.
158 * \todo XXX An interface for block size is needed.
162 * User identifier for quota purposes.
166 * Group identifier for quota purposes.
170 /* nlink of the directory */
173 /* Project identifier for quota purpose. */
178 * Fields in cl_attr that are being set.
193 * Sub-class of lu_object with methods common for objects on the client
196 * cl_object: represents a regular file system object, both a file and a
197 * stripe. cl_object is based on lu_object: it is identified by a fid,
198 * layered, cached, hashed, and lrued. Important distinction with the server
199 * side, where md_object and dt_object are used, is that cl_object "fans out"
200 * at the lov/sns level: depending on the file layout, single file is
201 * represented as a set of "sub-objects" (stripes). At the implementation
202 * level, struct lov_object contains an array of cl_objects. Each sub-object
203 * is a full-fledged cl_object, having its fid, living in the lru and hash
206 * This leads to the next important difference with the server side: on the
207 * client, it's quite usual to have objects with the different sequence of
208 * layers. For example, typical top-object is composed of the following
214 * whereas its sub-objects are composed of
219 * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep
220 * track of the object-subobject relationship.
222 * Sub-objects are not cached independently: when top-object is about to
223 * be discarded from the memory, all its sub-objects are torn-down and
226 * \see vvp_object, lov_object, lovsub_object, osc_object
230 struct lu_object co_lu;
231 /** per-object-layer operations */
232 const struct cl_object_operations *co_ops;
233 /** offset of page slice in cl_page buffer */
238 * Description of the client object configuration. This is used for the
239 * creation of a new client object that is identified by a more state than
242 struct cl_object_conf {
244 struct lu_object_conf coc_lu;
247 * Object layout. This is consumed by lov.
249 struct lu_buf coc_layout;
251 * Description of particular stripe location in the
252 * cluster. This is consumed by osc.
254 struct lov_oinfo *coc_oinfo;
257 * VFS inode. This is consumed by vvp.
259 struct inode *coc_inode;
261 * Layout lock handle.
263 struct ldlm_lock *coc_lock;
265 * Operation to handle layout, OBJECT_CONF_XYZ.
271 /** configure layout, set up a new stripe, must be called while
272 * holding layout lock. */
274 /** invalidate the current stripe configuration due to losing
276 OBJECT_CONF_INVALIDATE = 1,
277 /** wait for old layout to go away so that new layout can be
283 CL_LAYOUT_GEN_NONE = (u32)-2, /* layout lock was cancelled */
284 CL_LAYOUT_GEN_EMPTY = (u32)-1, /* for empty layout */
288 /** the buffer to return the layout in lov_mds_md format. */
289 struct lu_buf cl_buf;
290 /** size of layout in lov_mds_md format. */
292 /** Layout generation. */
294 /** whether layout is a composite one */
295 bool cl_is_composite;
296 /** Whether layout is a HSM released one */
301 * Operations implemented for each cl object layer.
303 * \see vvp_ops, lov_ops, lovsub_ops, osc_ops
305 struct cl_object_operations {
307 * Initialize page slice for this layer. Called top-to-bottom through
308 * every object layer when a new cl_page is instantiated. Layer
309 * keeping private per-page data, or requiring its own page operations
310 * vector should allocate these data here, and attach then to the page
311 * by calling cl_page_slice_add(). \a vmpage is locked (in the VM
314 * \retval NULL success.
316 * \retval ERR_PTR(errno) failure code.
318 * \retval valid-pointer pointer to already existing referenced page
319 * to be used instead of newly created.
321 int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj,
322 struct cl_page *page, pgoff_t index);
324 * Initialize lock slice for this layer. Called top-to-bottom through
325 * every object layer when a new cl_lock is instantiated. Layer
326 * keeping private per-lock data, or requiring its own lock operations
327 * vector should allocate these data here, and attach then to the lock
328 * by calling cl_lock_slice_add(). Mandatory.
330 int (*coo_lock_init)(const struct lu_env *env,
331 struct cl_object *obj, struct cl_lock *lock,
332 const struct cl_io *io);
334 * Initialize io state for a given layer.
336 * called top-to-bottom once per io existence to initialize io
337 * state. If layer wants to keep some state for this type of io, it
338 * has to embed struct cl_io_slice in lu_env::le_ses, and register
339 * slice with cl_io_slice_add(). It is guaranteed that all threads
340 * participating in this io share the same session.
342 int (*coo_io_init)(const struct lu_env *env,
343 struct cl_object *obj, struct cl_io *io);
345 * Fill portion of \a attr that this layer controls. This method is
346 * called top-to-bottom through all object layers.
348 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
350 * \return 0: to continue
351 * \return +ve: to stop iterating through layers (but 0 is returned
352 * from enclosing cl_object_attr_get())
353 * \return -ve: to signal error
355 int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj,
356 struct cl_attr *attr);
360 * \a valid is a bitmask composed from enum #cl_attr_valid, and
361 * indicating what attributes are to be set.
363 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
365 * \return the same convention as for
366 * cl_object_operations::coo_attr_get() is used.
368 int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj,
369 const struct cl_attr *attr, unsigned valid);
371 * Update object configuration. Called top-to-bottom to modify object
374 * XXX error conditions and handling.
376 int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj,
377 const struct cl_object_conf *conf);
379 * Glimpse ast. Executed when glimpse ast arrives for a lock on this
380 * object. Layers are supposed to fill parts of \a lvb that will be
381 * shipped to the glimpse originator as a glimpse result.
383 * \see vvp_object_glimpse(), lovsub_object_glimpse(),
384 * \see osc_object_glimpse()
386 int (*coo_glimpse)(const struct lu_env *env,
387 const struct cl_object *obj, struct ost_lvb *lvb);
389 * Object prune method. Called when the layout is going to change on
390 * this object, therefore each layer has to clean up their cache,
391 * mainly pages and locks.
393 int (*coo_prune)(const struct lu_env *env, struct cl_object *obj);
395 * Object getstripe method.
397 int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj,
398 struct lov_user_md __user *lum, size_t size);
400 * Get FIEMAP mapping from the object.
402 int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj,
403 struct ll_fiemap_info_key *fmkey,
404 struct fiemap *fiemap, size_t *buflen);
406 * Get layout and generation of the object.
408 int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj,
409 struct cl_layout *layout);
411 * Get maximum size of the object.
413 loff_t (*coo_maxbytes)(struct cl_object *obj);
415 * Set request attributes.
417 void (*coo_req_attr_set)(const struct lu_env *env,
418 struct cl_object *obj,
419 struct cl_req_attr *attr);
421 * Flush \a obj data corresponding to \a lock. Used for DoM
422 * locks in llite's cancelling blocking ast callback.
424 int (*coo_object_flush)(const struct lu_env *env,
425 struct cl_object *obj,
426 struct ldlm_lock *lock);
430 * Extended header for client object.
432 struct cl_object_header {
433 /** Standard lu_object_header. cl_object::co_lu::lo_header points
435 struct lu_object_header coh_lu;
438 * Parent object. It is assumed that an object has a well-defined
439 * parent, but not a well-defined child (there may be multiple
440 * sub-objects, for the same top-object). cl_object_header::coh_parent
441 * field allows certain code to be written generically, without
442 * limiting possible cl_object layouts unduly.
444 struct cl_object_header *coh_parent;
446 * Protects consistency between cl_attr of parent object and
447 * attributes of sub-objects, that the former is calculated ("merged")
450 * \todo XXX this can be read/write lock if needed.
452 spinlock_t coh_attr_guard;
454 * Size of cl_page + page slices
456 unsigned short coh_page_bufsize;
458 * Number of objects above this one: 0 for a top-object, 1 for its
461 unsigned char coh_nesting;
465 * Helper macro: iterate over all layers of the object \a obj, assigning every
466 * layer top-to-bottom to \a slice.
468 #define cl_object_for_each(slice, obj) \
469 list_for_each_entry((slice), \
470 &(obj)->co_lu.lo_header->loh_layers,\
474 * Helper macro: iterate over all layers of the object \a obj, assigning every
475 * layer bottom-to-top to \a slice.
477 #define cl_object_for_each_reverse(slice, obj) \
478 list_for_each_entry_reverse((slice), \
479 &(obj)->co_lu.lo_header->loh_layers,\
484 #define CL_PAGE_EOF ((pgoff_t)~0ull)
486 /** \addtogroup cl_page cl_page
490 * Layered client page.
492 * cl_page: represents a portion of a file, cached in the memory. All pages
493 * of the given file are of the same size, and are kept in the radix tree
494 * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects
495 * of the top-level file object are first class cl_objects, they have their
496 * own radix trees of pages and hence page is implemented as a sequence of
497 * struct cl_pages's, linked into double-linked list through
498 * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the
499 * corresponding radix tree at the corresponding logical offset.
501 * cl_page is associated with VM page of the hosting environment (struct
502 * page in Linux kernel, for example), struct page. It is assumed, that this
503 * association is implemented by one of cl_page layers (top layer in the
504 * current design) that
506 * - intercepts per-VM-page call-backs made by the environment (e.g.,
509 * - translates state (page flag bits) and locking between lustre and
512 * The association between cl_page and struct page is immutable and
513 * established when cl_page is created.
515 * cl_page can be "owned" by a particular cl_io (see below), guaranteeing
516 * this io an exclusive access to this page w.r.t. other io attempts and
517 * various events changing page state (such as transfer completion, or
518 * eviction of the page from the memory). Note, that in general cl_io
519 * cannot be identified with a particular thread, and page ownership is not
520 * exactly equal to the current thread holding a lock on the page. Layer
521 * implementing association between cl_page and struct page has to implement
522 * ownership on top of available synchronization mechanisms.
524 * While lustre client maintains the notion of an page ownership by io,
525 * hosting MM/VM usually has its own page concurrency control
526 * mechanisms. For example, in Linux, page access is synchronized by the
527 * per-page PG_locked bit-lock, and generic kernel code (generic_file_*())
528 * takes care to acquire and release such locks as necessary around the
529 * calls to the file system methods (->readpage(), ->prepare_write(),
530 * ->commit_write(), etc.). This leads to the situation when there are two
531 * different ways to own a page in the client:
533 * - client code explicitly and voluntary owns the page (cl_page_own());
535 * - VM locks a page and then calls the client, that has "to assume"
536 * the ownership from the VM (cl_page_assume()).
538 * Dual methods to release ownership are cl_page_disown() and
539 * cl_page_unassume().
541 * cl_page is reference counted (cl_page::cp_ref). When reference counter
542 * drops to 0, the page is returned to the cache, unless it is in
543 * cl_page_state::CPS_FREEING state, in which case it is immediately
546 * The general logic guaranteeing the absence of "existential races" for
547 * pages is the following:
549 * - there are fixed known ways for a thread to obtain a new reference
552 * - by doing a lookup in the cl_object radix tree, protected by the
555 * - by starting from VM-locked struct page and following some
556 * hosting environment method (e.g., following ->private pointer in
557 * the case of Linux kernel), see cl_vmpage_page();
559 * - when the page enters cl_page_state::CPS_FREEING state, all these
560 * ways are severed with the proper synchronization
561 * (cl_page_delete());
563 * - entry into cl_page_state::CPS_FREEING is serialized by the VM page
566 * - no new references to the page in cl_page_state::CPS_FREEING state
567 * are allowed (checked in cl_page_get()).
569 * Together this guarantees that when last reference to a
570 * cl_page_state::CPS_FREEING page is released, it is safe to destroy the
571 * page, as neither references to it can be acquired at that point, nor
574 * cl_page is a state machine. States are enumerated in enum
575 * cl_page_state. Possible state transitions are enumerated in
576 * cl_page_state_set(). State transition process (i.e., actual changing of
577 * cl_page::cp_state field) is protected by the lock on the underlying VM
580 * Linux Kernel implementation.
582 * Binding between cl_page and struct page (which is a typedef for
583 * struct page) is implemented in the vvp layer. cl_page is attached to the
584 * ->private pointer of the struct page, together with the setting of
585 * PG_private bit in page->flags, and acquiring additional reference on the
586 * struct page (much like struct buffer_head, or any similar file system
587 * private data structures).
589 * PG_locked lock is used to implement both ownership and transfer
590 * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}}
591 * states. No additional references are acquired for the duration of the
594 * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where
595 * write-out is "protected" by the special PG_writeback bit.
599 * States of cl_page. cl_page.c assumes particular order here.
601 * The page state machine is rather crude, as it doesn't recognize finer page
602 * states like "dirty" or "up to date". This is because such states are not
603 * always well defined for the whole stack (see, for example, the
604 * implementation of the read-ahead, that hides page up-to-dateness to track
605 * cache hits accurately). Such sub-states are maintained by the layers that
606 * are interested in them.
610 * Page is in the cache, un-owned. Page leaves cached state in the
613 * - [cl_page_state::CPS_OWNED] io comes across the page and
616 * - [cl_page_state::CPS_PAGEOUT] page is dirty, the
617 * req-formation engine decides that it wants to include this page
618 * into an RPC being constructed, and yanks it from the cache;
620 * - [cl_page_state::CPS_FREEING] VM callback is executed to
621 * evict the page form the memory;
623 * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL
627 * Page is exclusively owned by some cl_io. Page may end up in this
628 * state as a result of
630 * - io creating new page and immediately owning it;
632 * - [cl_page_state::CPS_CACHED] io finding existing cached page
635 * - [cl_page_state::CPS_OWNED] io finding existing owned page
636 * and waiting for owner to release the page;
638 * Page leaves owned state in the following cases:
640 * - [cl_page_state::CPS_CACHED] io decides to leave the page in
641 * the cache, doing nothing;
643 * - [cl_page_state::CPS_PAGEIN] io starts read transfer for
646 * - [cl_page_state::CPS_PAGEOUT] io starts immediate write
647 * transfer for this page;
649 * - [cl_page_state::CPS_FREEING] io decides to destroy this
650 * page (e.g., as part of truncate or extent lock cancellation).
652 * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL
656 * Page is being written out, as a part of a transfer. This state is
657 * entered when req-formation logic decided that it wants this page to
658 * be sent through the wire _now_. Specifically, it means that once
659 * this state is achieved, transfer completion handler (with either
660 * success or failure indication) is guaranteed to be executed against
661 * this page independently of any locks and any scheduling decisions
662 * made by the hosting environment (that effectively means that the
663 * page is never put into cl_page_state::CPS_PAGEOUT state "in
664 * advance". This property is mentioned, because it is important when
665 * reasoning about possible dead-locks in the system). The page can
666 * enter this state as a result of
668 * - [cl_page_state::CPS_OWNED] an io requesting an immediate
669 * write-out of this page, or
671 * - [cl_page_state::CPS_CACHED] req-forming engine deciding
672 * that it has enough dirty pages cached to issue a "good"
675 * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer
676 * is completed---it is moved into cl_page_state::CPS_CACHED state.
678 * Underlying VM page is locked for the duration of transfer.
680 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
684 * Page is being read in, as a part of a transfer. This is quite
685 * similar to the cl_page_state::CPS_PAGEOUT state, except that
686 * read-in is always "immediate"---there is no such thing a sudden
687 * construction of read request from cached, presumably not up to date,
690 * Underlying VM page is locked for the duration of transfer.
692 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
696 * Page is being destroyed. This state is entered when client decides
697 * that page has to be deleted from its host object, as, e.g., a part
700 * Once this state is reached, there is no way to escape it.
702 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL
709 /** Host page, the page is from the host inode which the cl_page
713 /** Transient page, the transient cl_page is used to bind a cl_page
714 * to vmpage which is not belonging to the same object of cl_page.
715 * it is used in DirectIO and lockless IO. */
720 #define CP_STATE_BITS 4
721 #define CP_TYPE_BITS 2
722 #define CP_MAX_LAYER 2
725 * Fields are protected by the lock on struct page, except for atomics and
728 * \invariant Data type invariants are in cl_page_invariant(). Basically:
729 * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked
730 * list, consistent with the parent/child pointers in the cl_page::cp_obj and
731 * cl_page::cp_owner (when set).
734 /** Reference counter. */
736 /** layout_entry + stripe index, composed using lov_comp_index() */
737 unsigned int cp_lov_index;
738 /** page->index of the page within the whole file */
739 pgoff_t cp_page_index;
740 /** An object this page is a part of. Immutable after creation. */
741 struct cl_object *cp_obj;
743 struct page *cp_vmpage;
745 * Assigned if doing direct IO, because in this case cp_vmpage is not
746 * a valid page cache page, hence the inode cannot be inferred from
747 * cp_vmpage->mapping->host.
749 struct inode *cp_inode;
750 /** Linkage of pages within group. Pages must be owned */
751 struct list_head cp_batch;
752 /** array of slices offset. Immutable after creation. */
753 unsigned char cp_layer_offset[CP_MAX_LAYER];
754 /** current slice index */
755 unsigned char cp_layer_count:2;
757 * Page state. This field is const to avoid accidental update, it is
758 * modified only internally within cl_page.c. Protected by a VM lock.
760 enum cl_page_state cp_state:CP_STATE_BITS;
762 * Page type. Only CPT_TRANSIENT is used so far. Immutable after
765 enum cl_page_type cp_type:CP_TYPE_BITS;
766 unsigned cp_defer_uptodate:1,
769 /* which slab kmem index this memory allocated from */
770 short int cp_kmem_index;
773 * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned
774 * by sub-io. Protected by a VM lock.
776 struct cl_io *cp_owner;
777 /** List of references to this page, for debugging. */
778 struct lu_ref cp_reference;
779 /** Link to an object, for debugging. */
780 struct lu_ref_link cp_obj_ref;
781 /** Link to a queue, for debugging. */
782 struct lu_ref_link cp_queue_ref;
783 /** Assigned if doing a sync_io */
784 struct cl_sync_io *cp_sync_io;
788 * Per-layer part of cl_page.
790 * \see vvp_page, lov_page, osc_page
792 struct cl_page_slice {
793 struct cl_page *cpl_page;
795 * Object slice corresponding to this page slice. Immutable after
798 struct cl_object *cpl_obj;
799 const struct cl_page_operations *cpl_ops;
803 * Lock mode. For the client extent locks.
815 * Requested transfer type.
824 * Per-layer page operations.
826 * Methods taking an \a io argument are for the activity happening in the
827 * context of given \a io. Page is assumed to be owned by that io, except for
830 * \see vvp_page_ops, lov_page_ops, osc_page_ops
832 struct cl_page_operations {
834 * cl_page<->struct page methods. Only one layer in the stack has to
835 * implement these. Current code assumes that this functionality is
836 * provided by the topmost layer, see cl_page_disown0() as an example.
840 * Called for a page that is already "owned" by \a io from VM point of
843 * \see cl_page_assume()
844 * \see vvp_page_assume(), lov_page_assume()
846 void (*cpo_assume)(const struct lu_env *env,
847 const struct cl_page_slice *slice, struct cl_io *io);
848 /** Dual to cl_page_operations::cpo_assume(). Optional. Called
849 * bottom-to-top when IO releases a page without actually unlocking
852 * \see cl_page_unassume()
853 * \see vvp_page_unassume()
855 void (*cpo_unassume)(const struct lu_env *env,
856 const struct cl_page_slice *slice,
859 * Update file attributes when all we have is this page. Used for tiny
860 * writes to update attributes when we don't have a full cl_io.
862 void (*cpo_page_touch)(const struct lu_env *env,
863 const struct cl_page_slice *slice, size_t to);
869 * Called when page is truncated from the object. Optional.
871 * \see cl_page_discard()
872 * \see vvp_page_discard(), osc_page_discard()
874 void (*cpo_discard)(const struct lu_env *env,
875 const struct cl_page_slice *slice,
878 * Called when page is removed from the cache, and is about to being
879 * destroyed. Optional.
881 * \see cl_page_delete()
882 * \see vvp_page_delete(), osc_page_delete()
884 void (*cpo_delete)(const struct lu_env *env,
885 const struct cl_page_slice *slice);
886 /** Destructor. Frees resources and slice itself. */
887 void (*cpo_fini)(const struct lu_env *env,
888 struct cl_page_slice *slice,
889 struct pagevec *pvec);
891 * Optional debugging helper. Prints given page slice.
893 * \see cl_page_print()
895 int (*cpo_print)(const struct lu_env *env,
896 const struct cl_page_slice *slice,
897 void *cookie, lu_printer_t p);
906 * Request type dependent vector of operations.
908 * Transfer operations depend on transfer mode (cl_req_type). To avoid
909 * passing transfer mode to each and every of these methods, and to
910 * avoid branching on request type inside of the methods, separate
911 * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
912 * provided. That is, method invocation usually looks like
914 * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
918 * Called when a page is submitted for a transfer as a part of
921 * \return 0 : page is eligible for submission;
922 * \return -EALREADY : skip this page;
923 * \return -ve : error.
925 * \see cl_page_prep()
927 int (*cpo_prep)(const struct lu_env *env,
928 const struct cl_page_slice *slice,
931 * Completion handler. This is guaranteed to be eventually
932 * fired after cl_page_operations::cpo_prep() or
933 * cl_page_operations::cpo_make_ready() call.
935 * This method can be called in a non-blocking context. It is
936 * guaranteed however, that the page involved and its object
937 * are pinned in memory (and, hence, calling cl_page_put() is
940 * \see cl_page_completion()
942 void (*cpo_completion)(const struct lu_env *env,
943 const struct cl_page_slice *slice,
946 * Called when cached page is about to be added to the
947 * ptlrpc request as a part of req formation.
949 * \return 0 : proceed with this page;
950 * \return -EAGAIN : skip this page;
951 * \return -ve : error.
953 * \see cl_page_make_ready()
955 int (*cpo_make_ready)(const struct lu_env *env,
956 const struct cl_page_slice *slice);
959 * Tell transfer engine that only [to, from] part of a page should be
962 * This is used for immediate transfers.
964 * \todo XXX this is not very good interface. It would be much better
965 * if all transfer parameters were supplied as arguments to
966 * cl_io_operations::cio_submit() call, but it is not clear how to do
967 * this for page queues.
969 * \see cl_page_clip()
971 void (*cpo_clip)(const struct lu_env *env,
972 const struct cl_page_slice *slice,
975 * Write out a page by kernel. This is only called by ll_writepage
978 * \see cl_page_flush()
980 int (*cpo_flush)(const struct lu_env *env,
981 const struct cl_page_slice *slice,
987 * Helper macro, dumping detailed information about \a page into a log.
989 #define CL_PAGE_DEBUG(mask, env, page, format, ...) \
991 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
992 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
993 cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
994 CDEBUG(mask, format , ## __VA_ARGS__); \
999 * Helper macro, dumping shorter information about \a page into a log.
1001 #define CL_PAGE_HEADER(mask, env, page, format, ...) \
1003 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1004 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1005 cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
1006 CDEBUG(mask, format , ## __VA_ARGS__); \
1010 static inline struct page *cl_page_vmpage(const struct cl_page *page)
1012 LASSERT(page->cp_vmpage != NULL);
1013 return page->cp_vmpage;
1017 * Check if a cl_page is in use.
1019 * Client cache holds a refcount, this refcount will be dropped when
1020 * the page is taken out of cache, see vvp_page_delete().
1022 static inline bool __page_in_use(const struct cl_page *page, int refc)
1024 return (atomic_read(&page->cp_ref) > refc + 1);
1028 * Caller itself holds a refcount of cl_page.
1030 #define cl_page_in_use(pg) __page_in_use(pg, 1)
1032 * Caller doesn't hold a refcount.
1034 #define cl_page_in_use_noref(pg) __page_in_use(pg, 0)
1036 /* references: cl_page, page cache, optional + refcount for caller reference
1037 * (always 0 or 1 currently)
1039 static inline int vmpage_in_use(struct page *vmpage, int refcount)
1041 return (page_count(vmpage) - page_mapcount(vmpage) > 2 + refcount);
1046 /** \addtogroup cl_lock cl_lock
1050 * Extent locking on the client.
1054 * The locking model of the new client code is built around
1058 * data-type representing an extent lock on a regular file. cl_lock is a
1059 * layered object (much like cl_object and cl_page), it consists of a header
1060 * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
1061 * cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
1063 * Typical cl_lock consists of one layer:
1065 * - lov_lock (lov specific data).
1067 * lov_lock contains an array of sub-locks. Each of these sub-locks is a
1068 * normal cl_lock: it has a header (struct cl_lock) and a list of layers:
1072 * Each sub-lock is associated with a cl_object (representing stripe
1073 * sub-object or the file to which top-level cl_lock is associated to), and is
1074 * linked into that cl_object::coh_locks. In this respect cl_lock is similar to
1075 * cl_object (that at lov layer also fans out into multiple sub-objects), and
1076 * is different from cl_page, that doesn't fan out (there is usually exactly
1077 * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
1078 * a "top-lock" and its lovsub-osc portion a "sub-lock".
1082 * cl_lock is a cacheless data container for the requirements of locks to
1083 * complete the IO. cl_lock is created before I/O starts and destroyed when the
1086 * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
1087 * to cl_lock at OSC layer. LDLM lock is still cacheable.
1089 * INTERFACE AND USAGE
1091 * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
1092 * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
1093 * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
1094 * consists of multiple sub cl_locks, each sub locks will be enqueued
1095 * correspondingly. At OSC layer, the lock enqueue request will tend to reuse
1096 * cached LDLM lock; otherwise a new LDLM lock will have to be requested from
1099 * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
1100 * method will be called for each layer to release the resource held by this
1101 * lock. At OSC layer, the reference count of LDLM lock, which is held at
1102 * clo_enqueue time, is released.
1104 * LDLM lock can only be canceled if there is no cl_lock using it.
1106 * Overall process of the locking during IO operation is as following:
1108 * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
1109 * is called on each layer. Responsibility of this method is to add locks,
1110 * needed by a given layer into cl_io.ci_lockset.
1112 * - once locks for all layers were collected, they are sorted to avoid
1113 * dead-locks (cl_io_locks_sort()), and enqueued.
1115 * - when all locks are acquired, IO is performed;
1117 * - locks are released after IO is complete.
1119 * Striping introduces major additional complexity into locking. The
1120 * fundamental problem is that it is generally unsafe to actively use (hold)
1121 * two locks on the different OST servers at the same time, as this introduces
1122 * inter-server dependency and can lead to cascading evictions.
1124 * Basic solution is to sub-divide large read/write IOs into smaller pieces so
1125 * that no multi-stripe locks are taken (note that this design abandons POSIX
1126 * read/write semantics). Such pieces ideally can be executed concurrently. At
1127 * the same time, certain types of IO cannot be sub-divived, without
1128 * sacrificing correctness. This includes:
1130 * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
1133 * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
1135 * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
1136 * buf is a part of memory mapped Lustre file, a lock or locks protecting buf
1137 * has to be held together with the usual lock on [offset, offset + count].
1139 * Interaction with DLM
1141 * In the expected setup, cl_lock is ultimately backed up by a collection of
1142 * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
1143 * implemented in osc layer, that also matches DLM events (ASTs, cancellation,
1144 * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
1145 * description of interaction with DLM.
1151 struct cl_lock_descr {
1152 /** Object this lock is granted for. */
1153 struct cl_object *cld_obj;
1154 /** Index of the first page protected by this lock. */
1156 /** Index of the last page (inclusive) protected by this lock. */
1158 /** Group ID, for group lock */
1161 enum cl_lock_mode cld_mode;
1163 * flags to enqueue lock. A combination of bit-flags from
1164 * enum cl_enq_flags.
1166 __u32 cld_enq_flags;
1169 #define DDESCR "%s(%d):[%lu, %lu]:%x"
1170 #define PDESCR(descr) \
1171 cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
1172 (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
1174 const char *cl_lock_mode_name(const enum cl_lock_mode mode);
1177 * Layered client lock.
1180 /** List of slices. Immutable after creation. */
1181 struct list_head cll_layers;
1182 /** lock attribute, extent, cl_object, etc. */
1183 struct cl_lock_descr cll_descr;
1187 * Per-layer part of cl_lock
1189 * \see lov_lock, osc_lock
1191 struct cl_lock_slice {
1192 struct cl_lock *cls_lock;
1193 /** Object slice corresponding to this lock slice. Immutable after
1195 struct cl_object *cls_obj;
1196 const struct cl_lock_operations *cls_ops;
1197 /** Linkage into cl_lock::cll_layers. Immutable after creation. */
1198 struct list_head cls_linkage;
1203 * \see lov_lock_ops, osc_lock_ops
1205 struct cl_lock_operations {
1208 * Attempts to enqueue the lock. Called top-to-bottom.
1210 * \retval 0 this layer has enqueued the lock successfully
1211 * \retval >0 this layer has enqueued the lock, but need to wait on
1212 * @anchor for resources
1213 * \retval -ve failure
1215 * \see lov_lock_enqueue(), osc_lock_enqueue()
1217 int (*clo_enqueue)(const struct lu_env *env,
1218 const struct cl_lock_slice *slice,
1219 struct cl_io *io, struct cl_sync_io *anchor);
1221 * Cancel a lock, release its DLM lock ref, while does not cancel the
1224 void (*clo_cancel)(const struct lu_env *env,
1225 const struct cl_lock_slice *slice);
1228 * Destructor. Frees resources and the slice.
1230 * \see lov_lock_fini(), osc_lock_fini()
1232 void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
1234 * Optional debugging helper. Prints given lock slice.
1236 int (*clo_print)(const struct lu_env *env,
1237 void *cookie, lu_printer_t p,
1238 const struct cl_lock_slice *slice);
1241 #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
1243 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1244 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1245 cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
1246 CDEBUG(mask, format , ## __VA_ARGS__); \
1250 #define CL_LOCK_ASSERT(expr, env, lock) do { \
1254 CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
1260 /** \addtogroup cl_page_list cl_page_list
1261 * Page list used to perform collective operations on a group of pages.
1263 * Pages are added to the list one by one. cl_page_list acquires a reference
1264 * for every page in it. Page list is used to perform collective operations on
1267 * - submit pages for an immediate transfer,
1269 * - own pages on behalf of certain io (waiting for each page in turn),
1273 * When list is finalized, it releases references on all pages it still has.
1275 * \todo XXX concurrency control.
1279 struct cl_page_list {
1281 struct list_head pl_pages;
1285 * A 2-queue of pages. A convenience data-type for common use case, 2-queue
1286 * contains an incoming page list and an outgoing page list.
1289 struct cl_page_list c2_qin;
1290 struct cl_page_list c2_qout;
1293 /** @} cl_page_list */
1295 /** \addtogroup cl_io cl_io
1300 * cl_io represents a high level I/O activity like
1301 * read(2)/write(2)/truncate(2) system call, or cancellation of an extent
1304 * cl_io is a layered object, much like cl_{object,page,lock} but with one
1305 * important distinction. We want to minimize number of calls to the allocator
1306 * in the fast path, e.g., in the case of read(2) when everything is cached:
1307 * client already owns the lock over region being read, and data are cached
1308 * due to read-ahead. To avoid allocation of cl_io layers in such situations,
1309 * per-layer io state is stored in the session, associated with the io, see
1310 * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
1311 * by using free-lists, see cl_env_get().
1313 * There is a small predefined number of possible io types, enumerated in enum
1316 * cl_io is a state machine, that can be advanced concurrently by the multiple
1317 * threads. It is up to these threads to control the concurrency and,
1318 * specifically, to detect when io is done, and its state can be safely
1321 * For read/write io overall execution plan is as following:
1323 * (0) initialize io state through all layers;
1325 * (1) loop: prepare chunk of work to do
1327 * (2) call all layers to collect locks they need to process current chunk
1329 * (3) sort all locks to avoid dead-locks, and acquire them
1331 * (4) process the chunk: call per-page methods
1332 * cl_io_operations::cio_prepare_write(),
1333 * cl_io_operations::cio_commit_write() for write)
1339 * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
1340 * address allocation efficiency issues mentioned above), and returns with the
1341 * special error condition from per-page method when current sub-io has to
1342 * block. This causes io loop to be repeated, and lov switches to the next
1343 * sub-io in its cl_io_operations::cio_iter_init() implementation.
1348 /** read system call */
1350 /** write system call */
1352 /** truncate, utime system calls */
1354 /** get data version */
1357 * page fault handling
1361 * fsync system call handling
1362 * To write out a range of file
1366 * glimpse. An io context to acquire glimpse lock.
1370 * Miscellaneous io. This is used for occasional io activity that
1371 * doesn't fit into other types. Currently this is used for:
1373 * - cancellation of an extent lock. This io exists as a context
1374 * to write dirty pages from under the lock being canceled back
1377 * - VM induced page write-out. An io context for writing page out
1378 * for memory cleansing;
1380 * - grouplock. An io context to acquire group lock.
1382 * CIT_MISC io is used simply as a context in which locks and pages
1383 * are manipulated. Such io has no internal "process", that is,
1384 * cl_io_loop() is never called for it.
1389 * To give advice about access of a file
1393 * SEEK_HOLE/SEEK_DATA handling to search holes or data
1394 * across all file objects
1401 * States of cl_io state machine
1404 /** Not initialized. */
1408 /** IO iteration started. */
1412 /** Actual IO is in progress. */
1414 /** IO for the current iteration finished. */
1416 /** Locks released. */
1418 /** Iteration completed. */
1420 /** cl_io finalized. */
1425 * IO state private for a layer.
1427 * This is usually embedded into layer session data, rather than allocated
1430 * \see vvp_io, lov_io, osc_io
1432 struct cl_io_slice {
1433 struct cl_io *cis_io;
1434 /** corresponding object slice. Immutable after creation. */
1435 struct cl_object *cis_obj;
1436 /** io operations. Immutable after creation. */
1437 const struct cl_io_operations *cis_iop;
1439 * linkage into a list of all slices for a given cl_io, hanging off
1440 * cl_io::ci_layers. Immutable after creation.
1442 struct list_head cis_linkage;
1445 typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
1448 struct cl_read_ahead {
1449 /* Maximum page index the readahead window will end.
1450 * This is determined DLM lock coverage, RPC and stripe boundary.
1451 * cra_end is included. */
1452 pgoff_t cra_end_idx;
1453 /* optimal RPC size for this read, by pages */
1454 unsigned long cra_rpc_pages;
1455 /* Release callback. If readahead holds resources underneath, this
1456 * function should be called to release it. */
1457 void (*cra_release)(const struct lu_env *env,
1458 struct cl_read_ahead *ra);
1460 /* Callback data for cra_release routine */
1464 /* whether lock is in contention */
1465 bool cra_contention;
1468 static inline void cl_read_ahead_release(const struct lu_env *env,
1469 struct cl_read_ahead *ra)
1471 if (ra->cra_release != NULL)
1472 ra->cra_release(env, ra);
1473 memset(ra, 0, sizeof(*ra));
1478 * Per-layer io operations.
1479 * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
1481 struct cl_io_operations {
1483 * Vector of io state transition methods for every io type.
1485 * \see cl_page_operations::io
1489 * Prepare io iteration at a given layer.
1491 * Called top-to-bottom at the beginning of each iteration of
1492 * "io loop" (if it makes sense for this type of io). Here
1493 * layer selects what work it will do during this iteration.
1495 * \see cl_io_operations::cio_iter_fini()
1497 int (*cio_iter_init) (const struct lu_env *env,
1498 const struct cl_io_slice *slice);
1500 * Finalize io iteration.
1502 * Called bottom-to-top at the end of each iteration of "io
1503 * loop". Here layers can decide whether IO has to be
1506 * \see cl_io_operations::cio_iter_init()
1508 void (*cio_iter_fini) (const struct lu_env *env,
1509 const struct cl_io_slice *slice);
1511 * Collect locks for the current iteration of io.
1513 * Called top-to-bottom to collect all locks necessary for
1514 * this iteration. This methods shouldn't actually enqueue
1515 * anything, instead it should post a lock through
1516 * cl_io_lock_add(). Once all locks are collected, they are
1517 * sorted and enqueued in the proper order.
1519 int (*cio_lock) (const struct lu_env *env,
1520 const struct cl_io_slice *slice);
1522 * Finalize unlocking.
1524 * Called bottom-to-top to finish layer specific unlocking
1525 * functionality, after generic code released all locks
1526 * acquired by cl_io_operations::cio_lock().
1528 void (*cio_unlock)(const struct lu_env *env,
1529 const struct cl_io_slice *slice);
1531 * Start io iteration.
1533 * Once all locks are acquired, called top-to-bottom to
1534 * commence actual IO. In the current implementation,
1535 * top-level vvp_io_{read,write}_start() does all the work
1536 * synchronously by calling generic_file_*(), so other layers
1537 * are called when everything is done.
1539 int (*cio_start)(const struct lu_env *env,
1540 const struct cl_io_slice *slice);
1542 * Called top-to-bottom at the end of io loop. Here layer
1543 * might wait for an unfinished asynchronous io.
1545 void (*cio_end) (const struct lu_env *env,
1546 const struct cl_io_slice *slice);
1548 * Called bottom-to-top to notify layers that read/write IO
1549 * iteration finished, with \a nob bytes transferred.
1551 void (*cio_advance)(const struct lu_env *env,
1552 const struct cl_io_slice *slice,
1555 * Called once per io, bottom-to-top to release io resources.
1557 void (*cio_fini) (const struct lu_env *env,
1558 const struct cl_io_slice *slice);
1562 * Submit pages from \a queue->c2_qin for IO, and move
1563 * successfully submitted pages into \a queue->c2_qout. Return
1564 * non-zero if failed to submit even the single page. If
1565 * submission failed after some pages were moved into \a
1566 * queue->c2_qout, completion callback with non-zero ioret is
1569 int (*cio_submit)(const struct lu_env *env,
1570 const struct cl_io_slice *slice,
1571 enum cl_req_type crt,
1572 struct cl_2queue *queue);
1574 * Queue async page for write.
1575 * The difference between cio_submit and cio_queue is that
1576 * cio_submit is for urgent request.
1578 int (*cio_commit_async)(const struct lu_env *env,
1579 const struct cl_io_slice *slice,
1580 struct cl_page_list *queue, int from, int to,
1583 * Release active extent.
1585 void (*cio_extent_release)(const struct lu_env *env,
1586 const struct cl_io_slice *slice);
1588 * Decide maximum read ahead extent
1590 * \pre io->ci_type == CIT_READ
1592 int (*cio_read_ahead)(const struct lu_env *env,
1593 const struct cl_io_slice *slice,
1594 pgoff_t start, struct cl_read_ahead *ra);
1597 * Reserve LRU slots before IO.
1599 int (*cio_lru_reserve) (const struct lu_env *env,
1600 const struct cl_io_slice *slice,
1601 loff_t pos, size_t bytes);
1603 * Optional debugging helper. Print given io slice.
1605 int (*cio_print)(const struct lu_env *env, void *cookie,
1606 lu_printer_t p, const struct cl_io_slice *slice);
1610 * Flags to lock enqueue procedure.
1615 * instruct server to not block, if conflicting lock is found. Instead
1616 * -EAGAIN is returned immediately.
1618 CEF_NONBLOCK = 0x00000001,
1620 * Tell lower layers this is a glimpse request, translated to
1621 * LDLM_FL_HAS_INTENT at LDLM layer.
1623 * Also, because glimpse locks never block other locks, we count this
1624 * as automatically compatible with other osc locks.
1625 * (see osc_lock_compatible)
1627 CEF_GLIMPSE = 0x00000002,
1629 * tell the server to instruct (though a flag in the blocking ast) an
1630 * owner of the conflicting lock, that it can drop dirty pages
1631 * protected by this lock, without sending them to the server.
1633 CEF_DISCARD_DATA = 0x00000004,
1635 * tell the sub layers that it must be a `real' lock. This is used for
1636 * mmapped-buffer locks, glimpse locks, manually requested locks
1637 * (LU_LADVISE_LOCKAHEAD) that must never be converted into lockless
1640 * \see vvp_mmap_locks(), cl_glimpse_lock, cl_request_lock().
1642 CEF_MUST = 0x00000008,
1644 * tell the sub layers that never request a `real' lock. This flag is
1645 * not used currently.
1647 * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
1648 * conversion policy: ci_lockreq describes generic information of lock
1649 * requirement for this IO, especially for locks which belong to the
1650 * object doing IO; however, lock itself may have precise requirements
1651 * that are described by the enqueue flags.
1653 CEF_NEVER = 0x00000010,
1655 * tell the dlm layer this is a speculative lock request
1656 * speculative lock requests are locks which are not requested as part
1657 * of an I/O operation. Instead, they are requested because we expect
1658 * to use them in the future. They are requested asynchronously at the
1661 * Currently used for asynchronous glimpse locks and manually requested
1662 * locks (LU_LADVISE_LOCKAHEAD).
1664 CEF_SPECULATIVE = 0x00000020,
1666 * enqueue a lock to test DLM lock existence.
1668 CEF_PEEK = 0x00000040,
1670 * Lock match only. Used by group lock in I/O as group lock
1671 * is known to exist.
1673 CEF_LOCK_MATCH = 0x00000080,
1675 * tell the DLM layer to lock only the requested range
1677 CEF_LOCK_NO_EXPAND = 0x00000100,
1679 * mask of enq_flags.
1681 CEF_MASK = 0x000001ff,
1685 * Link between lock and io. Intermediate structure is needed, because the
1686 * same lock can be part of multiple io's simultaneously.
1688 struct cl_io_lock_link {
1689 /** linkage into one of cl_lockset lists. */
1690 struct list_head cill_linkage;
1691 struct cl_lock cill_lock;
1692 /** optional destructor */
1693 void (*cill_fini)(const struct lu_env *env,
1694 struct cl_io_lock_link *link);
1696 #define cill_descr cill_lock.cll_descr
1699 * Lock-set represents a collection of locks, that io needs at a
1700 * time. Generally speaking, client tries to avoid holding multiple locks when
1703 * - holding extent locks over multiple ost's introduces the danger of
1704 * "cascading timeouts";
1706 * - holding multiple locks over the same ost is still dead-lock prone,
1707 * see comment in osc_lock_enqueue(),
1709 * but there are certain situations where this is unavoidable:
1711 * - O_APPEND writes have to take [0, EOF] lock for correctness;
1713 * - truncate has to take [new-size, EOF] lock for correctness;
1715 * - SNS has to take locks across full stripe for correctness;
1717 * - in the case when user level buffer, supplied to {read,write}(file0),
1718 * is a part of a memory mapped lustre file, client has to take a dlm
1719 * locks on file0, and all files that back up the buffer (or a part of
1720 * the buffer, that is being processed in the current chunk, in any
1721 * case, there are situations where at least 2 locks are necessary).
1723 * In such cases we at least try to take locks in the same consistent
1724 * order. To this end, all locks are first collected, then sorted, and then
1728 /** locks to be acquired. */
1729 struct list_head cls_todo;
1730 /** locks acquired. */
1731 struct list_head cls_done;
1735 * Lock requirements(demand) for IO. It should be cl_io_lock_req,
1736 * but 'req' is always to be thought as 'request' :-)
1738 enum cl_io_lock_dmd {
1739 /** Always lock data (e.g., O_APPEND). */
1741 /** Layers are free to decide between local and global locking. */
1743 /** Never lock: there is no cache (e.g., liblustre). */
1747 enum cl_fsync_mode {
1748 /** start writeback, do not wait for them to finish */
1750 /** start writeback and wait for them to finish */
1752 /** discard all of dirty pages in a specific file range */
1753 CL_FSYNC_DISCARD = 2,
1754 /** start writeback and make sure they have reached storage before
1755 * return. OST_SYNC RPC must be issued and finished */
1759 struct cl_io_rw_common {
1764 enum cl_setattr_subtype {
1765 /** regular setattr **/
1769 /** fallocate(2) - mode preallocate **/
1770 CL_SETATTR_FALLOCATE
1773 struct cl_io_range {
1779 struct cl_io_pt *cip_next;
1780 struct kiocb cip_iocb;
1781 struct iov_iter cip_iter;
1782 struct file *cip_file;
1783 enum cl_io_type cip_iot;
1784 unsigned int cip_need_restart:1;
1793 * cl_io is shared by all threads participating in this IO (in current
1794 * implementation only one thread advances IO, but parallel IO design and
1795 * concurrent copy_*_user() require multiple threads acting on the same IO. It
1796 * is up to these threads to serialize their activities, including updates to
1797 * mutable cl_io fields.
1800 /** type of this IO. Immutable after creation. */
1801 enum cl_io_type ci_type;
1802 /** current state of cl_io state machine. */
1803 enum cl_io_state ci_state;
1804 /** main object this io is against. Immutable after creation. */
1805 struct cl_object *ci_obj;
1806 /** one AIO request might be split in cl_io_loop */
1807 struct cl_dio_aio *ci_aio;
1809 * Upper layer io, of which this io is a part of. Immutable after
1812 struct cl_io *ci_parent;
1813 /** List of slices. Immutable after creation. */
1814 struct list_head ci_layers;
1815 /** list of locks (to be) acquired by this io. */
1816 struct cl_lockset ci_lockset;
1817 /** lock requirements, this is just a help info for sublayers. */
1818 enum cl_io_lock_dmd ci_lockreq;
1819 /** layout version when this IO occurs */
1820 __u32 ci_layout_version;
1823 struct cl_io_rw_common rd;
1826 struct cl_io_rw_common wr;
1830 struct cl_io_rw_common ci_rw;
1831 struct cl_setattr_io {
1832 struct ost_lvb sa_attr;
1833 unsigned int sa_attr_flags;
1834 unsigned int sa_avalid; /* ATTR_* */
1835 unsigned int sa_xvalid; /* OP_XVALID */
1836 int sa_stripe_index;
1837 struct ost_layout sa_layout;
1838 const struct lu_fid *sa_parent_fid;
1839 /* SETATTR interface is used for regular setattr, */
1840 /* truncate(2) and fallocate(2) subtypes */
1841 enum cl_setattr_subtype sa_subtype;
1842 /* The following are used for fallocate(2) */
1844 loff_t sa_falloc_offset;
1845 loff_t sa_falloc_end;
1846 uid_t sa_falloc_uid;
1847 gid_t sa_falloc_gid;
1848 __u32 sa_falloc_projid;
1850 struct cl_data_version_io {
1851 u64 dv_data_version;
1852 u32 dv_layout_version;
1855 struct cl_fault_io {
1856 /** page index within file. */
1858 /** bytes valid byte on a faulted page. */
1860 /** writable page? for nopage() only */
1862 /** page of an executable? */
1864 /** page_mkwrite() */
1866 /** resulting page */
1867 struct cl_page *ft_page;
1869 struct cl_fsync_io {
1872 /** file system level fid */
1873 struct lu_fid *fi_fid;
1874 enum cl_fsync_mode fi_mode;
1875 /* how many pages were written/discarded */
1876 unsigned int fi_nr_written;
1878 struct cl_ladvise_io {
1881 /** file system level fid */
1882 struct lu_fid *li_fid;
1883 enum lu_ladvise_type li_advice;
1886 struct cl_lseek_io {
1892 time64_t lm_next_rpc_time;
1895 struct cl_2queue ci_queue;
1898 unsigned int ci_continue:1,
1900 * This io has held grouplock, to inform sublayers that
1901 * don't do lockless i/o.
1905 * The whole IO need to be restarted because layout has been changed
1909 * to not refresh layout - the IO issuer knows that the layout won't
1910 * change(page operations, layout change causes all page to be
1911 * discarded), or it doesn't matter if it changes(sync).
1915 * Need MDS intervention to complete a write.
1916 * Write intent is required for the following cases:
1917 * 1. component being written is not initialized, or
1918 * 2. the mirrored files are NOT in WRITE_PENDING state.
1920 ci_need_write_intent:1,
1922 * Check if layout changed after the IO finishes. Mainly for HSM
1923 * requirement. If IO occurs to openning files, it doesn't need to
1924 * verify layout because HSM won't release openning files.
1925 * Right now, only two opertaions need to verify layout: glimpse
1930 * file is released, restore has to to be triggered by vvp layer
1932 ci_restore_needed:1,
1937 /* Tell sublayers not to expand LDLM locks requested for this IO */
1938 ci_lock_no_expand:1,
1940 * Set if non-delay RPC should be used for this IO.
1942 * If this file has multiple mirrors, and if the OSTs of the current
1943 * mirror is inaccessible, non-delay RPC would error out quickly so
1944 * that the upper layer can try to access the next mirror.
1948 * Set if IO is triggered by async workqueue readahead.
1950 ci_async_readahead:1,
1952 * Ignore lockless and do normal locking for this io.
1956 * Set if we've tried all mirrors for this read IO, if it's not set,
1957 * the read IO will check to-be-read OSCs' status, and make fast-switch
1958 * another mirror if some of the OSTs are not healthy.
1960 ci_tried_all_mirrors:1,
1962 * Random read hints, readahead will be disabled.
1966 * Sequential read hints.
1970 * Do parallel (async) submission of DIO RPCs. Note DIO is still sync
1971 * to userspace, only the RPCs are submitted async, then waited for at
1972 * the llite layer before returning.
1976 * Bypass quota check
1978 unsigned ci_noquota:1;
1980 * How many times the read has retried before this one.
1981 * Set by the top level and consumed by the LOV.
1983 unsigned ci_ndelay_tried;
1985 * Designated mirror index for this I/O.
1987 unsigned ci_designated_mirror;
1989 * Number of pages owned by this IO. For invariant checking.
1991 unsigned ci_owned_nr;
1993 * Range of write intent. Valid if ci_need_write_intent is set.
1995 struct lu_extent ci_write_intent;
2001 * Per-transfer attributes.
2003 struct cl_req_attr {
2004 enum cl_req_type cra_type;
2006 struct cl_page *cra_page;
2007 /** Generic attributes for the server consumption. */
2008 struct obdo *cra_oa;
2010 char cra_jobid[LUSTRE_JOBID_SIZE];
2013 enum cache_stats_item {
2014 /** how many cache lookups were performed */
2016 /** how many times cache lookup resulted in a hit */
2018 /** how many entities are in the cache right now */
2020 /** how many entities in the cache are actively used (and cannot be
2021 * evicted) right now */
2023 /** how many entities were created at all */
2028 #define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
2031 * Stats for a generic cache (similar to inode, lu_object, etc. caches).
2033 struct cache_stats {
2034 const char *cs_name;
2035 atomic_t cs_stats[CS_NR];
2038 /** These are not exported so far */
2039 void cache_stats_init (struct cache_stats *cs, const char *name);
2042 * Client-side site. This represents particular client stack. "Global"
2043 * variables should (directly or indirectly) be added here to allow multiple
2044 * clients to co-exist in the single address space.
2047 struct lu_site cs_lu;
2049 * Statistical counters. Atomics do not scale, something better like
2050 * per-cpu counters is needed.
2052 * These are exported as /proc/fs/lustre/llite/.../site
2054 * When interpreting keep in mind that both sub-locks (and sub-pages)
2055 * and top-locks (and top-pages) are accounted here.
2057 struct cache_stats cs_pages;
2058 atomic_t cs_pages_state[CPS_NR];
2061 int cl_site_init(struct cl_site *s, struct cl_device *top);
2062 void cl_site_fini(struct cl_site *s);
2063 void cl_stack_fini(const struct lu_env *env, struct cl_device *cl);
2066 * Output client site statistical counters into a buffer. Suitable for
2067 * ll_rd_*()-style functions.
2069 int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
2074 * Type conversion and accessory functions.
2078 static inline struct cl_site *lu2cl_site(const struct lu_site *site)
2080 return container_of(site, struct cl_site, cs_lu);
2083 static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
2085 LASSERT(d == NULL || IS_ERR(d) || lu_device_is_cl(d));
2086 return container_of_safe(d, struct cl_device, cd_lu_dev);
2089 static inline struct lu_device *cl2lu_dev(struct cl_device *d)
2091 return &d->cd_lu_dev;
2094 static inline struct cl_object *lu2cl(const struct lu_object *o)
2096 LASSERT(o == NULL || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
2097 return container_of_safe(o, struct cl_object, co_lu);
2100 static inline const struct cl_object_conf *
2101 lu2cl_conf(const struct lu_object_conf *conf)
2103 return container_of_safe(conf, struct cl_object_conf, coc_lu);
2106 static inline struct cl_object *cl_object_next(const struct cl_object *obj)
2108 return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL;
2111 static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
2113 return container_of_safe(h, struct cl_object_header, coh_lu);
2116 static inline struct cl_site *cl_object_site(const struct cl_object *obj)
2118 return lu2cl_site(obj->co_lu.lo_dev->ld_site);
2122 struct cl_object_header *cl_object_header(const struct cl_object *obj)
2124 return luh2coh(obj->co_lu.lo_header);
2127 static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
2129 return lu_device_init(&d->cd_lu_dev, t);
2132 static inline void cl_device_fini(struct cl_device *d)
2134 lu_device_fini(&d->cd_lu_dev);
2137 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
2138 struct cl_object *obj,
2139 const struct cl_page_operations *ops);
2140 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
2141 struct cl_object *obj,
2142 const struct cl_lock_operations *ops);
2143 void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
2144 struct cl_object *obj, const struct cl_io_operations *ops);
2147 /** \defgroup cl_object cl_object
2149 struct cl_object *cl_object_top (struct cl_object *o);
2150 struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
2151 const struct lu_fid *fid,
2152 const struct cl_object_conf *c);
2154 int cl_object_header_init(struct cl_object_header *h);
2155 void cl_object_header_fini(struct cl_object_header *h);
2156 void cl_object_put (const struct lu_env *env, struct cl_object *o);
2157 void cl_object_get (struct cl_object *o);
2158 void cl_object_attr_lock (struct cl_object *o);
2159 void cl_object_attr_unlock(struct cl_object *o);
2160 int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
2161 struct cl_attr *attr);
2162 int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
2163 const struct cl_attr *attr, unsigned valid);
2164 int cl_object_glimpse (const struct lu_env *env, struct cl_object *obj,
2165 struct ost_lvb *lvb);
2166 int cl_conf_set (const struct lu_env *env, struct cl_object *obj,
2167 const struct cl_object_conf *conf);
2168 int cl_object_prune (const struct lu_env *env, struct cl_object *obj);
2169 void cl_object_kill (const struct lu_env *env, struct cl_object *obj);
2170 int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj,
2171 struct lov_user_md __user *lum, size_t size);
2172 int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj,
2173 struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap,
2175 int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj,
2176 struct cl_layout *cl);
2177 loff_t cl_object_maxbytes(struct cl_object *obj);
2178 int cl_object_flush(const struct lu_env *env, struct cl_object *obj,
2179 struct ldlm_lock *lock);
2183 * Returns true, iff \a o0 and \a o1 are slices of the same object.
2185 static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
2187 return cl_object_header(o0) == cl_object_header(o1);
2190 static inline void cl_object_page_init(struct cl_object *clob, int size)
2192 clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
2193 cl_object_header(clob)->coh_page_bufsize += cfs_size_round(size);
2194 WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
2197 static inline void *cl_object_page_slice(struct cl_object *clob,
2198 struct cl_page *page)
2200 return (void *)((char *)page + clob->co_slice_off);
2204 * Return refcount of cl_object.
2206 static inline int cl_object_refc(struct cl_object *clob)
2208 struct lu_object_header *header = clob->co_lu.lo_header;
2209 return atomic_read(&header->loh_ref);
2214 /** \defgroup cl_page cl_page
2216 struct cl_page *cl_page_find (const struct lu_env *env,
2217 struct cl_object *obj,
2218 pgoff_t idx, struct page *vmpage,
2219 enum cl_page_type type);
2220 struct cl_page *cl_page_alloc (const struct lu_env *env,
2221 struct cl_object *o, pgoff_t ind,
2222 struct page *vmpage,
2223 enum cl_page_type type);
2224 void cl_page_get (struct cl_page *page);
2225 void cl_page_put (const struct lu_env *env,
2226 struct cl_page *page);
2227 void cl_pagevec_put (const struct lu_env *env,
2228 struct cl_page *page,
2229 struct pagevec *pvec);
2230 void cl_page_print (const struct lu_env *env, void *cookie,
2231 lu_printer_t printer,
2232 const struct cl_page *pg);
2233 void cl_page_header_print(const struct lu_env *env, void *cookie,
2234 lu_printer_t printer,
2235 const struct cl_page *pg);
2236 struct cl_page *cl_vmpage_page (struct page *vmpage, struct cl_object *obj);
2237 struct cl_page *cl_page_top (struct cl_page *page);
2239 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
2240 const struct lu_device_type *dtype);
2245 * Functions dealing with the ownership of page by io.
2249 int cl_page_own (const struct lu_env *env,
2250 struct cl_io *io, struct cl_page *page);
2251 int cl_page_own_try (const struct lu_env *env,
2252 struct cl_io *io, struct cl_page *page);
2253 void cl_page_assume (const struct lu_env *env,
2254 struct cl_io *io, struct cl_page *page);
2255 void cl_page_unassume (const struct lu_env *env,
2256 struct cl_io *io, struct cl_page *pg);
2257 void cl_page_disown (const struct lu_env *env,
2258 struct cl_io *io, struct cl_page *page);
2259 int cl_page_is_owned (const struct cl_page *pg, const struct cl_io *io);
2266 * Functions dealing with the preparation of a page for a transfer, and
2267 * tracking transfer state.
2270 int cl_page_prep (const struct lu_env *env, struct cl_io *io,
2271 struct cl_page *pg, enum cl_req_type crt);
2272 void cl_page_completion (const struct lu_env *env,
2273 struct cl_page *pg, enum cl_req_type crt, int ioret);
2274 int cl_page_make_ready (const struct lu_env *env, struct cl_page *pg,
2275 enum cl_req_type crt);
2276 int cl_page_cache_add (const struct lu_env *env, struct cl_io *io,
2277 struct cl_page *pg, enum cl_req_type crt);
2278 void cl_page_clip (const struct lu_env *env, struct cl_page *pg,
2280 int cl_page_flush (const struct lu_env *env, struct cl_io *io,
2281 struct cl_page *pg);
2287 * \name helper routines
2288 * Functions to discard, delete and export a cl_page.
2291 void cl_page_discard(const struct lu_env *env, struct cl_io *io,
2292 struct cl_page *pg);
2293 void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
2294 void cl_page_touch(const struct lu_env *env, const struct cl_page *pg,
2296 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx);
2297 pgoff_t cl_index(const struct cl_object *obj, loff_t offset);
2298 size_t cl_page_size(const struct cl_object *obj);
2300 void cl_lock_print(const struct lu_env *env, void *cookie,
2301 lu_printer_t printer, const struct cl_lock *lock);
2302 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2303 lu_printer_t printer,
2304 const struct cl_lock_descr *descr);
2308 * Data structure managing a client's cached pages. A count of
2309 * "unstable" pages is maintained, and an LRU of clean pages is
2310 * maintained. "unstable" pages are pages pinned by the ptlrpc
2311 * layer for recovery purposes.
2313 struct cl_client_cache {
2315 * # of client cache refcount
2316 * # of users (OSCs) + 2 (held by llite and lov)
2320 * # of threads are doing shrinking
2322 unsigned int ccc_lru_shrinkers;
2324 * # of LRU entries available
2326 atomic_long_t ccc_lru_left;
2328 * List of entities(OSCs) for this LRU cache
2330 struct list_head ccc_lru;
2332 * Max # of LRU entries
2334 unsigned long ccc_lru_max;
2336 * Lock to protect ccc_lru list
2338 spinlock_t ccc_lru_lock;
2340 * Set if unstable check is enabled
2342 unsigned int ccc_unstable_check:1;
2344 * # of unstable pages for this mount point
2346 atomic_long_t ccc_unstable_nr;
2348 * Waitq for awaiting unstable pages to reach zero.
2349 * Used at umounting time and signaled on BRW commit
2351 wait_queue_head_t ccc_unstable_waitq;
2353 * Serialize max_cache_mb write operation
2355 struct mutex ccc_max_cache_mb_lock;
2358 * cl_cache functions
2360 struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
2361 void cl_cache_incref(struct cl_client_cache *cache);
2362 void cl_cache_decref(struct cl_client_cache *cache);
2366 /** \defgroup cl_lock cl_lock
2368 int cl_lock_request(const struct lu_env *env, struct cl_io *io,
2369 struct cl_lock *lock);
2370 int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
2371 const struct cl_io *io);
2372 void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
2373 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
2374 const struct lu_device_type *dtype);
2375 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
2377 int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
2378 struct cl_lock *lock, struct cl_sync_io *anchor);
2379 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
2383 /** \defgroup cl_io cl_io
2386 int cl_io_init (const struct lu_env *env, struct cl_io *io,
2387 enum cl_io_type iot, struct cl_object *obj);
2388 int cl_io_sub_init (const struct lu_env *env, struct cl_io *io,
2389 enum cl_io_type iot, struct cl_object *obj);
2390 int cl_io_rw_init (const struct lu_env *env, struct cl_io *io,
2391 enum cl_io_type iot, loff_t pos, size_t count);
2392 int cl_io_loop (const struct lu_env *env, struct cl_io *io);
2394 void cl_io_fini (const struct lu_env *env, struct cl_io *io);
2395 int cl_io_iter_init (const struct lu_env *env, struct cl_io *io);
2396 void cl_io_iter_fini (const struct lu_env *env, struct cl_io *io);
2397 int cl_io_lock (const struct lu_env *env, struct cl_io *io);
2398 void cl_io_unlock (const struct lu_env *env, struct cl_io *io);
2399 int cl_io_start (const struct lu_env *env, struct cl_io *io);
2400 void cl_io_end (const struct lu_env *env, struct cl_io *io);
2401 int cl_io_lock_add (const struct lu_env *env, struct cl_io *io,
2402 struct cl_io_lock_link *link);
2403 int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
2404 struct cl_lock_descr *descr);
2405 int cl_io_submit_rw (const struct lu_env *env, struct cl_io *io,
2406 enum cl_req_type iot, struct cl_2queue *queue);
2407 int cl_io_submit_sync (const struct lu_env *env, struct cl_io *io,
2408 enum cl_req_type iot, struct cl_2queue *queue,
2410 int cl_io_commit_async (const struct lu_env *env, struct cl_io *io,
2411 struct cl_page_list *queue, int from, int to,
2413 void cl_io_extent_release (const struct lu_env *env, struct cl_io *io);
2414 int cl_io_lru_reserve(const struct lu_env *env, struct cl_io *io,
2415 loff_t pos, size_t bytes);
2416 int cl_io_read_ahead (const struct lu_env *env, struct cl_io *io,
2417 pgoff_t start, struct cl_read_ahead *ra);
2418 void cl_io_rw_advance (const struct lu_env *env, struct cl_io *io,
2422 * True, iff \a io is an O_APPEND write(2).
2424 static inline int cl_io_is_append(const struct cl_io *io)
2426 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
2429 static inline int cl_io_is_sync_write(const struct cl_io *io)
2431 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
2434 static inline int cl_io_is_mkwrite(const struct cl_io *io)
2436 return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
2440 * True, iff \a io is a truncate(2).
2442 static inline int cl_io_is_trunc(const struct cl_io *io)
2444 return io->ci_type == CIT_SETATTR &&
2445 (io->u.ci_setattr.sa_avalid & ATTR_SIZE) &&
2446 (io->u.ci_setattr.sa_subtype != CL_SETATTR_FALLOCATE);
2449 static inline int cl_io_is_fallocate(const struct cl_io *io)
2451 return (io->ci_type == CIT_SETATTR) &&
2452 (io->u.ci_setattr.sa_subtype == CL_SETATTR_FALLOCATE);
2455 struct cl_io *cl_io_top(struct cl_io *io);
2457 void cl_io_print(const struct lu_env *env, void *cookie,
2458 lu_printer_t printer, const struct cl_io *io);
2460 #define CL_IO_SLICE_CLEAN(foo_io, base) \
2462 typeof(foo_io) __foo_io = (foo_io); \
2464 memset(&__foo_io->base, 0, \
2465 sizeof(*__foo_io) - offsetof(typeof(*__foo_io), base)); \
2470 /** \defgroup cl_page_list cl_page_list
2474 * Last page in the page list.
2476 static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
2478 LASSERT(plist->pl_nr > 0);
2479 return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
2482 static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
2484 LASSERT(plist->pl_nr > 0);
2485 return list_first_entry(&plist->pl_pages, struct cl_page, cp_batch);
2489 * Iterate over pages in a page list.
2491 #define cl_page_list_for_each(page, list) \
2492 list_for_each_entry((page), &(list)->pl_pages, cp_batch)
2495 * Iterate over pages in a page list, taking possible removals into account.
2497 #define cl_page_list_for_each_safe(page, temp, list) \
2498 list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
2500 void cl_page_list_init(struct cl_page_list *plist);
2501 void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page,
2503 void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src,
2504 struct cl_page *page);
2505 void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
2506 struct cl_page *page);
2507 void cl_page_list_splice(struct cl_page_list *list,
2508 struct cl_page_list *head);
2509 void cl_page_list_del(const struct lu_env *env,
2510 struct cl_page_list *plist, struct cl_page *page);
2511 void cl_page_list_disown(const struct lu_env *env,
2512 struct cl_page_list *plist);
2513 void cl_page_list_assume(const struct lu_env *env,
2514 struct cl_io *io, struct cl_page_list *plist);
2515 void cl_page_list_discard(const struct lu_env *env,
2516 struct cl_io *io, struct cl_page_list *plist);
2517 void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist);
2519 void cl_2queue_init(struct cl_2queue *queue);
2520 void cl_2queue_add(struct cl_2queue *queue, struct cl_page *page,
2522 void cl_2queue_disown(const struct lu_env *env, struct cl_2queue *queue);
2523 void cl_2queue_assume(const struct lu_env *env, struct cl_io *io,
2524 struct cl_2queue *queue);
2525 void cl_2queue_discard(const struct lu_env *env, struct cl_io *io,
2526 struct cl_2queue *queue);
2527 void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue);
2528 void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
2530 /** @} cl_page_list */
2532 void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
2533 struct cl_req_attr *attr);
2535 /** \defgroup cl_sync_io cl_sync_io
2541 typedef void (cl_sync_io_end_t)(const struct lu_env *, struct cl_sync_io *);
2543 void cl_sync_io_init_notify(struct cl_sync_io *anchor, int nr,
2544 struct cl_dio_aio *aio, cl_sync_io_end_t *end);
2546 int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
2548 void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
2550 int cl_sync_io_wait_recycle(const struct lu_env *env, struct cl_sync_io *anchor,
2551 long timeout, int ioret);
2552 struct cl_dio_aio *cl_aio_alloc(struct kiocb *iocb, struct cl_object *obj,
2553 struct cl_dio_aio *ll_aio);
2554 void cl_aio_free(const struct lu_env *env, struct cl_dio_aio *aio);
2555 static inline void cl_sync_io_init(struct cl_sync_io *anchor, int nr)
2557 cl_sync_io_init_notify(anchor, nr, NULL, NULL);
2561 * Anchor for synchronous transfer. This is allocated on a stack by thread
2562 * doing synchronous transfer, and a pointer to this structure is set up in
2563 * every page submitted for transfer. Transfer completion routine updates
2564 * anchor and wakes up waiting thread when transfer is complete.
2567 /** number of pages yet to be transferred. */
2568 atomic_t csi_sync_nr;
2571 /** completion to be signaled when transfer is complete. */
2572 wait_queue_head_t csi_waitq;
2573 /** callback to invoke when this IO is finished */
2574 cl_sync_io_end_t *csi_end_io;
2575 /** aio private data */
2576 struct cl_dio_aio *csi_aio;
2579 /** direct IO pages */
2580 struct ll_dio_pages {
2582 * page array to be written. we don't support
2583 * partial pages except the last one.
2585 struct page **ldp_pages;
2586 /** # of pages in the array. */
2588 /* the file offset of the first page. */
2589 loff_t ldp_file_offset;
2592 /** To support Direct AIO */
2594 struct cl_sync_io cda_sync;
2595 struct cl_page_list cda_pages;
2596 struct cl_object *cda_obj;
2597 struct kiocb *cda_iocb;
2599 struct cl_dio_aio *cda_ll_aio;
2600 struct ll_dio_pages cda_dio_pages;
2601 unsigned cda_no_aio_complete:1,
2605 #if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW) || \
2606 defined(HAVE_DIRECTIO_2ARGS)
2607 #define HAVE_DIO_ITER 1
2610 void ll_release_user_pages(struct page **pages, int npages);
2612 /** @} cl_sync_io */
2614 /** \defgroup cl_env cl_env
2616 * lu_env handling for a client.
2618 * lu_env is an environment within which lustre code executes. Its major part
2619 * is lu_context---a fast memory allocation mechanism that is used to conserve
2620 * precious kernel stack space. Originally lu_env was designed for a server,
2623 * - there is a (mostly) fixed number of threads, and
2625 * - call chains have no non-lustre portions inserted between lustre code.
2627 * On a client both these assumtpion fails, because every user thread can
2628 * potentially execute lustre code as part of a system call, and lustre calls
2629 * into VFS or MM that call back into lustre.
2631 * To deal with that, cl_env wrapper functions implement the following
2634 * - allocation and destruction of environment is amortized by caching no
2635 * longer used environments instead of destroying them;
2637 * \see lu_env, lu_context, lu_context_key
2640 struct lu_env *cl_env_get(__u16 *refcheck);
2641 struct lu_env *cl_env_alloc(__u16 *refcheck, __u32 tags);
2642 void cl_env_put(struct lu_env *env, __u16 *refcheck);
2643 unsigned cl_env_cache_purge(unsigned nr);
2644 struct lu_env *cl_env_percpu_get(void);
2645 void cl_env_percpu_put(struct lu_env *env);
2652 void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr);
2653 void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
2655 struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
2656 struct lu_device_type *ldt,
2657 struct lu_device *next);
2660 int cl_global_init(void);
2661 void cl_global_fini(void);
2663 #endif /* _LINUX_CL_OBJECT_H */