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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 * Update file attributes when all we have is this page. Used for tiny
841 * writes to update attributes when we don't have a full cl_io.
843 void (*cpo_page_touch)(const struct lu_env *env,
844 const struct cl_page_slice *slice, size_t to);
850 * Called when page is truncated from the object. Optional.
852 * \see cl_page_discard()
853 * \see vvp_page_discard(), osc_page_discard()
855 void (*cpo_discard)(const struct lu_env *env,
856 const struct cl_page_slice *slice,
859 * Called when page is removed from the cache, and is about to being
860 * destroyed. Optional.
862 * \see cl_page_delete()
863 * \see vvp_page_delete(), osc_page_delete()
865 void (*cpo_delete)(const struct lu_env *env,
866 const struct cl_page_slice *slice);
868 * Optional debugging helper. Prints given page slice.
870 * \see cl_page_print()
872 int (*cpo_print)(const struct lu_env *env,
873 const struct cl_page_slice *slice,
874 void *cookie, lu_printer_t p);
883 * Request type dependent vector of operations.
885 * Transfer operations depend on transfer mode (cl_req_type). To avoid
886 * passing transfer mode to each and every of these methods, and to
887 * avoid branching on request type inside of the methods, separate
888 * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
889 * provided. That is, method invocation usually looks like
891 * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
895 * Called when a page is submitted for a transfer as a part of
898 * \return 0 : page is eligible for submission;
899 * \return -EALREADY : skip this page;
900 * \return -ve : error.
902 * \see cl_page_prep()
904 int (*cpo_prep)(const struct lu_env *env,
905 const struct cl_page_slice *slice,
908 * Completion handler. This is guaranteed to be eventually
909 * fired after cl_page_operations::cpo_prep() or
910 * cl_page_operations::cpo_make_ready() call.
912 * This method can be called in a non-blocking context. It is
913 * guaranteed however, that the page involved and its object
914 * are pinned in memory (and, hence, calling cl_page_put() is
917 * \see cl_page_completion()
919 void (*cpo_completion)(const struct lu_env *env,
920 const struct cl_page_slice *slice,
923 * Called when cached page is about to be added to the
924 * ptlrpc request as a part of req formation.
926 * \return 0 : proceed with this page;
927 * \return -EAGAIN : skip this page;
928 * \return -ve : error.
930 * \see cl_page_make_ready()
932 int (*cpo_make_ready)(const struct lu_env *env,
933 const struct cl_page_slice *slice);
936 * Tell transfer engine that only [to, from] part of a page should be
939 * This is used for immediate transfers.
941 * \todo XXX this is not very good interface. It would be much better
942 * if all transfer parameters were supplied as arguments to
943 * cl_io_operations::cio_submit() call, but it is not clear how to do
944 * this for page queues.
946 * \see cl_page_clip()
948 void (*cpo_clip)(const struct lu_env *env,
949 const struct cl_page_slice *slice,
952 * Write out a page by kernel. This is only called by ll_writepage
955 * \see cl_page_flush()
957 int (*cpo_flush)(const struct lu_env *env,
958 const struct cl_page_slice *slice,
964 * Helper macro, dumping detailed information about \a page into a log.
966 #define CL_PAGE_DEBUG(mask, env, page, format, ...) \
968 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
969 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
970 cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
971 CDEBUG(mask, format , ## __VA_ARGS__); \
976 * Helper macro, dumping shorter information about \a page into a log.
978 #define CL_PAGE_HEADER(mask, env, page, format, ...) \
980 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
981 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
982 cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
983 CDEBUG(mask, format , ## __VA_ARGS__); \
987 static inline struct page *cl_page_vmpage(const struct cl_page *page)
989 LASSERT(page->cp_vmpage != NULL);
990 return page->cp_vmpage;
994 * Check if a cl_page is in use.
996 * Client cache holds a refcount, this refcount will be dropped when
997 * the page is taken out of cache, see vvp_page_delete().
999 static inline bool __page_in_use(const struct cl_page *page, int refc)
1001 return (atomic_read(&page->cp_ref) > refc + 1);
1005 * Caller itself holds a refcount of cl_page.
1007 #define cl_page_in_use(pg) __page_in_use(pg, 1)
1009 * Caller doesn't hold a refcount.
1011 #define cl_page_in_use_noref(pg) __page_in_use(pg, 0)
1013 /* references: cl_page, page cache, optional + refcount for caller reference
1014 * (always 0 or 1 currently)
1016 static inline int vmpage_in_use(struct page *vmpage, int refcount)
1018 return (page_count(vmpage) - page_mapcount(vmpage) > 2 + refcount);
1023 /** \addtogroup cl_lock cl_lock
1027 * Extent locking on the client.
1031 * The locking model of the new client code is built around
1035 * data-type representing an extent lock on a regular file. cl_lock is a
1036 * layered object (much like cl_object and cl_page), it consists of a header
1037 * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
1038 * cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
1040 * Typical cl_lock consists of one layer:
1042 * - lov_lock (lov specific data).
1044 * lov_lock contains an array of sub-locks. Each of these sub-locks is a
1045 * normal cl_lock: it has a header (struct cl_lock) and a list of layers:
1049 * Each sub-lock is associated with a cl_object (representing stripe
1050 * sub-object or the file to which top-level cl_lock is associated to), and is
1051 * linked into that cl_object::coh_locks. In this respect cl_lock is similar to
1052 * cl_object (that at lov layer also fans out into multiple sub-objects), and
1053 * is different from cl_page, that doesn't fan out (there is usually exactly
1054 * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
1055 * a "top-lock" and its lovsub-osc portion a "sub-lock".
1059 * cl_lock is a cacheless data container for the requirements of locks to
1060 * complete the IO. cl_lock is created before I/O starts and destroyed when the
1063 * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
1064 * to cl_lock at OSC layer. LDLM lock is still cacheable.
1066 * INTERFACE AND USAGE
1068 * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
1069 * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
1070 * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
1071 * consists of multiple sub cl_locks, each sub locks will be enqueued
1072 * correspondingly. At OSC layer, the lock enqueue request will tend to reuse
1073 * cached LDLM lock; otherwise a new LDLM lock will have to be requested from
1076 * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
1077 * method will be called for each layer to release the resource held by this
1078 * lock. At OSC layer, the reference count of LDLM lock, which is held at
1079 * clo_enqueue time, is released.
1081 * LDLM lock can only be canceled if there is no cl_lock using it.
1083 * Overall process of the locking during IO operation is as following:
1085 * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
1086 * is called on each layer. Responsibility of this method is to add locks,
1087 * needed by a given layer into cl_io.ci_lockset.
1089 * - once locks for all layers were collected, they are sorted to avoid
1090 * dead-locks (cl_io_locks_sort()), and enqueued.
1092 * - when all locks are acquired, IO is performed;
1094 * - locks are released after IO is complete.
1096 * Striping introduces major additional complexity into locking. The
1097 * fundamental problem is that it is generally unsafe to actively use (hold)
1098 * two locks on the different OST servers at the same time, as this introduces
1099 * inter-server dependency and can lead to cascading evictions.
1101 * Basic solution is to sub-divide large read/write IOs into smaller pieces so
1102 * that no multi-stripe locks are taken (note that this design abandons POSIX
1103 * read/write semantics). Such pieces ideally can be executed concurrently. At
1104 * the same time, certain types of IO cannot be sub-divived, without
1105 * sacrificing correctness. This includes:
1107 * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
1110 * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
1112 * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
1113 * buf is a part of memory mapped Lustre file, a lock or locks protecting buf
1114 * has to be held together with the usual lock on [offset, offset + count].
1116 * Interaction with DLM
1118 * In the expected setup, cl_lock is ultimately backed up by a collection of
1119 * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
1120 * implemented in osc layer, that also matches DLM events (ASTs, cancellation,
1121 * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
1122 * description of interaction with DLM.
1128 struct cl_lock_descr {
1129 /** Object this lock is granted for. */
1130 struct cl_object *cld_obj;
1131 /** Index of the first page protected by this lock. */
1133 /** Index of the last page (inclusive) protected by this lock. */
1135 /** Group ID, for group lock */
1138 enum cl_lock_mode cld_mode;
1140 * flags to enqueue lock. A combination of bit-flags from
1141 * enum cl_enq_flags.
1143 __u32 cld_enq_flags;
1146 #define DDESCR "%s(%d):[%lu, %lu]:%x"
1147 #define PDESCR(descr) \
1148 cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
1149 (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
1151 const char *cl_lock_mode_name(const enum cl_lock_mode mode);
1154 * Layered client lock.
1157 /** List of slices. Immutable after creation. */
1158 struct list_head cll_layers;
1159 /** lock attribute, extent, cl_object, etc. */
1160 struct cl_lock_descr cll_descr;
1164 * Per-layer part of cl_lock
1166 * \see lov_lock, osc_lock
1168 struct cl_lock_slice {
1169 struct cl_lock *cls_lock;
1170 /** Object slice corresponding to this lock slice. Immutable after
1172 struct cl_object *cls_obj;
1173 const struct cl_lock_operations *cls_ops;
1174 /** Linkage into cl_lock::cll_layers. Immutable after creation. */
1175 struct list_head cls_linkage;
1180 * \see lov_lock_ops, osc_lock_ops
1182 struct cl_lock_operations {
1185 * Attempts to enqueue the lock. Called top-to-bottom.
1187 * \retval 0 this layer has enqueued the lock successfully
1188 * \retval >0 this layer has enqueued the lock, but need to wait on
1189 * @anchor for resources
1190 * \retval -ve failure
1192 * \see lov_lock_enqueue(), osc_lock_enqueue()
1194 int (*clo_enqueue)(const struct lu_env *env,
1195 const struct cl_lock_slice *slice,
1196 struct cl_io *io, struct cl_sync_io *anchor);
1198 * Cancel a lock, release its DLM lock ref, while does not cancel the
1201 void (*clo_cancel)(const struct lu_env *env,
1202 const struct cl_lock_slice *slice);
1205 * Destructor. Frees resources and the slice.
1207 * \see lov_lock_fini(), osc_lock_fini()
1209 void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
1211 * Optional debugging helper. Prints given lock slice.
1213 int (*clo_print)(const struct lu_env *env,
1214 void *cookie, lu_printer_t p,
1215 const struct cl_lock_slice *slice);
1218 #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
1220 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1221 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1222 cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
1223 CDEBUG(mask, format , ## __VA_ARGS__); \
1227 #define CL_LOCK_ASSERT(expr, env, lock) do { \
1231 CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
1237 /** \addtogroup cl_page_list cl_page_list
1238 * Page list used to perform collective operations on a group of pages.
1240 * Pages are added to the list one by one. cl_page_list acquires a reference
1241 * for every page in it. Page list is used to perform collective operations on
1244 * - submit pages for an immediate transfer,
1246 * - own pages on behalf of certain io (waiting for each page in turn),
1250 * When list is finalized, it releases references on all pages it still has.
1252 * \todo XXX concurrency control.
1256 struct cl_page_list {
1258 struct list_head pl_pages;
1262 * A 2-queue of pages. A convenience data-type for common use case, 2-queue
1263 * contains an incoming page list and an outgoing page list.
1266 struct cl_page_list c2_qin;
1267 struct cl_page_list c2_qout;
1270 /** @} cl_page_list */
1272 /** \addtogroup cl_io cl_io
1277 * cl_io represents a high level I/O activity like
1278 * read(2)/write(2)/truncate(2) system call, or cancellation of an extent
1281 * cl_io is a layered object, much like cl_{object,page,lock} but with one
1282 * important distinction. We want to minimize number of calls to the allocator
1283 * in the fast path, e.g., in the case of read(2) when everything is cached:
1284 * client already owns the lock over region being read, and data are cached
1285 * due to read-ahead. To avoid allocation of cl_io layers in such situations,
1286 * per-layer io state is stored in the session, associated with the io, see
1287 * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
1288 * by using free-lists, see cl_env_get().
1290 * There is a small predefined number of possible io types, enumerated in enum
1293 * cl_io is a state machine, that can be advanced concurrently by the multiple
1294 * threads. It is up to these threads to control the concurrency and,
1295 * specifically, to detect when io is done, and its state can be safely
1298 * For read/write io overall execution plan is as following:
1300 * (0) initialize io state through all layers;
1302 * (1) loop: prepare chunk of work to do
1304 * (2) call all layers to collect locks they need to process current chunk
1306 * (3) sort all locks to avoid dead-locks, and acquire them
1308 * (4) process the chunk: call per-page methods
1309 * cl_io_operations::cio_prepare_write(),
1310 * cl_io_operations::cio_commit_write() for write)
1316 * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
1317 * address allocation efficiency issues mentioned above), and returns with the
1318 * special error condition from per-page method when current sub-io has to
1319 * block. This causes io loop to be repeated, and lov switches to the next
1320 * sub-io in its cl_io_operations::cio_iter_init() implementation.
1325 /** read system call */
1327 /** write system call */
1329 /** truncate, utime system calls */
1331 /** get data version */
1334 * page fault handling
1338 * fsync system call handling
1339 * To write out a range of file
1343 * glimpse. An io context to acquire glimpse lock.
1347 * Miscellaneous io. This is used for occasional io activity that
1348 * doesn't fit into other types. Currently this is used for:
1350 * - cancellation of an extent lock. This io exists as a context
1351 * to write dirty pages from under the lock being canceled back
1354 * - VM induced page write-out. An io context for writing page out
1355 * for memory cleansing;
1357 * - grouplock. An io context to acquire group lock.
1359 * CIT_MISC io is used simply as a context in which locks and pages
1360 * are manipulated. Such io has no internal "process", that is,
1361 * cl_io_loop() is never called for it.
1366 * To give advice about access of a file
1370 * SEEK_HOLE/SEEK_DATA handling to search holes or data
1371 * across all file objects
1378 * States of cl_io state machine
1381 /** Not initialized. */
1385 /** IO iteration started. */
1389 /** Actual IO is in progress. */
1391 /** IO for the current iteration finished. */
1393 /** Locks released. */
1395 /** Iteration completed. */
1397 /** cl_io finalized. */
1402 * IO state private for a layer.
1404 * This is usually embedded into layer session data, rather than allocated
1407 * \see vvp_io, lov_io, osc_io
1409 struct cl_io_slice {
1410 struct cl_io *cis_io;
1411 /** corresponding object slice. Immutable after creation. */
1412 struct cl_object *cis_obj;
1413 /** io operations. Immutable after creation. */
1414 const struct cl_io_operations *cis_iop;
1416 * linkage into a list of all slices for a given cl_io, hanging off
1417 * cl_io::ci_layers. Immutable after creation.
1419 struct list_head cis_linkage;
1422 typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
1425 struct cl_read_ahead {
1426 /* Maximum page index the readahead window will end.
1427 * This is determined DLM lock coverage, RPC and stripe boundary.
1428 * cra_end is included. */
1429 pgoff_t cra_end_idx;
1430 /* optimal RPC size for this read, by pages */
1431 unsigned long cra_rpc_pages;
1432 /* Release callback. If readahead holds resources underneath, this
1433 * function should be called to release it. */
1434 void (*cra_release)(const struct lu_env *env,
1435 struct cl_read_ahead *ra);
1437 /* Callback data for cra_release routine */
1441 /* whether lock is in contention */
1442 bool cra_contention;
1445 static inline void cl_read_ahead_release(const struct lu_env *env,
1446 struct cl_read_ahead *ra)
1448 if (ra->cra_release != NULL)
1449 ra->cra_release(env, ra);
1450 memset(ra, 0, sizeof(*ra));
1455 * Per-layer io operations.
1456 * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
1458 struct cl_io_operations {
1460 * Vector of io state transition methods for every io type.
1462 * \see cl_page_operations::io
1466 * Prepare io iteration at a given layer.
1468 * Called top-to-bottom at the beginning of each iteration of
1469 * "io loop" (if it makes sense for this type of io). Here
1470 * layer selects what work it will do during this iteration.
1472 * \see cl_io_operations::cio_iter_fini()
1474 int (*cio_iter_init) (const struct lu_env *env,
1475 const struct cl_io_slice *slice);
1477 * Finalize io iteration.
1479 * Called bottom-to-top at the end of each iteration of "io
1480 * loop". Here layers can decide whether IO has to be
1483 * \see cl_io_operations::cio_iter_init()
1485 void (*cio_iter_fini) (const struct lu_env *env,
1486 const struct cl_io_slice *slice);
1488 * Collect locks for the current iteration of io.
1490 * Called top-to-bottom to collect all locks necessary for
1491 * this iteration. This methods shouldn't actually enqueue
1492 * anything, instead it should post a lock through
1493 * cl_io_lock_add(). Once all locks are collected, they are
1494 * sorted and enqueued in the proper order.
1496 int (*cio_lock) (const struct lu_env *env,
1497 const struct cl_io_slice *slice);
1499 * Finalize unlocking.
1501 * Called bottom-to-top to finish layer specific unlocking
1502 * functionality, after generic code released all locks
1503 * acquired by cl_io_operations::cio_lock().
1505 void (*cio_unlock)(const struct lu_env *env,
1506 const struct cl_io_slice *slice);
1508 * Start io iteration.
1510 * Once all locks are acquired, called top-to-bottom to
1511 * commence actual IO. In the current implementation,
1512 * top-level vvp_io_{read,write}_start() does all the work
1513 * synchronously by calling generic_file_*(), so other layers
1514 * are called when everything is done.
1516 int (*cio_start)(const struct lu_env *env,
1517 const struct cl_io_slice *slice);
1519 * Called top-to-bottom at the end of io loop. Here layer
1520 * might wait for an unfinished asynchronous io.
1522 void (*cio_end) (const struct lu_env *env,
1523 const struct cl_io_slice *slice);
1525 * Called bottom-to-top to notify layers that read/write IO
1526 * iteration finished, with \a nob bytes transferred.
1528 void (*cio_advance)(const struct lu_env *env,
1529 const struct cl_io_slice *slice,
1532 * Called once per io, bottom-to-top to release io resources.
1534 void (*cio_fini) (const struct lu_env *env,
1535 const struct cl_io_slice *slice);
1539 * Submit pages from \a queue->c2_qin for IO, and move
1540 * successfully submitted pages into \a queue->c2_qout. Return
1541 * non-zero if failed to submit even the single page. If
1542 * submission failed after some pages were moved into \a
1543 * queue->c2_qout, completion callback with non-zero ioret is
1546 int (*cio_submit)(const struct lu_env *env,
1547 const struct cl_io_slice *slice,
1548 enum cl_req_type crt,
1549 struct cl_2queue *queue);
1551 * Queue async page for write.
1552 * The difference between cio_submit and cio_queue is that
1553 * cio_submit is for urgent request.
1555 int (*cio_commit_async)(const struct lu_env *env,
1556 const struct cl_io_slice *slice,
1557 struct cl_page_list *queue, int from, int to,
1560 * Release active extent.
1562 void (*cio_extent_release)(const struct lu_env *env,
1563 const struct cl_io_slice *slice);
1565 * Decide maximum read ahead extent
1567 * \pre io->ci_type == CIT_READ
1569 int (*cio_read_ahead)(const struct lu_env *env,
1570 const struct cl_io_slice *slice,
1571 pgoff_t start, struct cl_read_ahead *ra);
1574 * Reserve LRU slots before IO.
1576 int (*cio_lru_reserve) (const struct lu_env *env,
1577 const struct cl_io_slice *slice,
1578 loff_t pos, size_t bytes);
1580 * Optional debugging helper. Print given io slice.
1582 int (*cio_print)(const struct lu_env *env, void *cookie,
1583 lu_printer_t p, const struct cl_io_slice *slice);
1587 * Flags to lock enqueue procedure.
1592 * instruct server to not block, if conflicting lock is found. Instead
1593 * -EAGAIN is returned immediately.
1595 CEF_NONBLOCK = 0x00000001,
1597 * Tell lower layers this is a glimpse request, translated to
1598 * LDLM_FL_HAS_INTENT at LDLM layer.
1600 * Also, because glimpse locks never block other locks, we count this
1601 * as automatically compatible with other osc locks.
1602 * (see osc_lock_compatible)
1604 CEF_GLIMPSE = 0x00000002,
1606 * tell the server to instruct (though a flag in the blocking ast) an
1607 * owner of the conflicting lock, that it can drop dirty pages
1608 * protected by this lock, without sending them to the server.
1610 CEF_DISCARD_DATA = 0x00000004,
1612 * tell the sub layers that it must be a `real' lock. This is used for
1613 * mmapped-buffer locks, glimpse locks, manually requested locks
1614 * (LU_LADVISE_LOCKAHEAD) that must never be converted into lockless
1617 * \see vvp_mmap_locks(), cl_glimpse_lock, cl_request_lock().
1619 CEF_MUST = 0x00000008,
1621 * tell the sub layers that never request a `real' lock. This flag is
1622 * not used currently.
1624 * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
1625 * conversion policy: ci_lockreq describes generic information of lock
1626 * requirement for this IO, especially for locks which belong to the
1627 * object doing IO; however, lock itself may have precise requirements
1628 * that are described by the enqueue flags.
1630 CEF_NEVER = 0x00000010,
1632 * tell the dlm layer this is a speculative lock request
1633 * speculative lock requests are locks which are not requested as part
1634 * of an I/O operation. Instead, they are requested because we expect
1635 * to use them in the future. They are requested asynchronously at the
1638 * Currently used for asynchronous glimpse locks and manually requested
1639 * locks (LU_LADVISE_LOCKAHEAD).
1641 CEF_SPECULATIVE = 0x00000020,
1643 * enqueue a lock to test DLM lock existence.
1645 CEF_PEEK = 0x00000040,
1647 * Lock match only. Used by group lock in I/O as group lock
1648 * is known to exist.
1650 CEF_LOCK_MATCH = 0x00000080,
1652 * tell the DLM layer to lock only the requested range
1654 CEF_LOCK_NO_EXPAND = 0x00000100,
1656 * mask of enq_flags.
1658 CEF_MASK = 0x000001ff,
1662 * Link between lock and io. Intermediate structure is needed, because the
1663 * same lock can be part of multiple io's simultaneously.
1665 struct cl_io_lock_link {
1666 /** linkage into one of cl_lockset lists. */
1667 struct list_head cill_linkage;
1668 struct cl_lock cill_lock;
1669 /** optional destructor */
1670 void (*cill_fini)(const struct lu_env *env,
1671 struct cl_io_lock_link *link);
1673 #define cill_descr cill_lock.cll_descr
1676 * Lock-set represents a collection of locks, that io needs at a
1677 * time. Generally speaking, client tries to avoid holding multiple locks when
1680 * - holding extent locks over multiple ost's introduces the danger of
1681 * "cascading timeouts";
1683 * - holding multiple locks over the same ost is still dead-lock prone,
1684 * see comment in osc_lock_enqueue(),
1686 * but there are certain situations where this is unavoidable:
1688 * - O_APPEND writes have to take [0, EOF] lock for correctness;
1690 * - truncate has to take [new-size, EOF] lock for correctness;
1692 * - SNS has to take locks across full stripe for correctness;
1694 * - in the case when user level buffer, supplied to {read,write}(file0),
1695 * is a part of a memory mapped lustre file, client has to take a dlm
1696 * locks on file0, and all files that back up the buffer (or a part of
1697 * the buffer, that is being processed in the current chunk, in any
1698 * case, there are situations where at least 2 locks are necessary).
1700 * In such cases we at least try to take locks in the same consistent
1701 * order. To this end, all locks are first collected, then sorted, and then
1705 /** locks to be acquired. */
1706 struct list_head cls_todo;
1707 /** locks acquired. */
1708 struct list_head cls_done;
1712 * Lock requirements(demand) for IO. It should be cl_io_lock_req,
1713 * but 'req' is always to be thought as 'request' :-)
1715 enum cl_io_lock_dmd {
1716 /** Always lock data (e.g., O_APPEND). */
1718 /** Layers are free to decide between local and global locking. */
1720 /** Never lock: there is no cache (e.g., liblustre). */
1724 enum cl_fsync_mode {
1725 /** start writeback, do not wait for them to finish */
1727 /** start writeback and wait for them to finish */
1729 /** discard all of dirty pages in a specific file range */
1730 CL_FSYNC_DISCARD = 2,
1731 /** start writeback and make sure they have reached storage before
1732 * return. OST_SYNC RPC must be issued and finished */
1736 struct cl_io_rw_common {
1741 enum cl_setattr_subtype {
1742 /** regular setattr **/
1746 /** fallocate(2) - mode preallocate **/
1747 CL_SETATTR_FALLOCATE
1750 struct cl_io_range {
1756 struct cl_io_pt *cip_next;
1757 struct kiocb cip_iocb;
1758 struct iov_iter cip_iter;
1759 struct file *cip_file;
1760 enum cl_io_type cip_iot;
1761 unsigned int cip_need_restart:1;
1770 * cl_io is shared by all threads participating in this IO (in current
1771 * implementation only one thread advances IO, but parallel IO design and
1772 * concurrent copy_*_user() require multiple threads acting on the same IO. It
1773 * is up to these threads to serialize their activities, including updates to
1774 * mutable cl_io fields.
1777 /** type of this IO. Immutable after creation. */
1778 enum cl_io_type ci_type;
1779 /** current state of cl_io state machine. */
1780 enum cl_io_state ci_state;
1781 /** main object this io is against. Immutable after creation. */
1782 struct cl_object *ci_obj;
1783 /** top level dio_aio */
1784 struct cl_dio_aio *ci_dio_aio;
1786 * Upper layer io, of which this io is a part of. Immutable after
1789 struct cl_io *ci_parent;
1790 /** List of slices. Immutable after creation. */
1791 struct list_head ci_layers;
1792 /** list of locks (to be) acquired by this io. */
1793 struct cl_lockset ci_lockset;
1794 /** lock requirements, this is just a help info for sublayers. */
1795 enum cl_io_lock_dmd ci_lockreq;
1796 /** layout version when this IO occurs */
1797 __u32 ci_layout_version;
1800 struct cl_io_rw_common rd;
1803 struct cl_io_rw_common wr;
1807 struct cl_io_rw_common ci_rw;
1808 struct cl_setattr_io {
1809 struct ost_lvb sa_attr;
1810 unsigned int sa_attr_flags;
1811 unsigned int sa_avalid; /* ATTR_* */
1812 unsigned int sa_xvalid; /* OP_XVALID */
1813 int sa_stripe_index;
1814 struct ost_layout sa_layout;
1815 const struct lu_fid *sa_parent_fid;
1816 /* SETATTR interface is used for regular setattr, */
1817 /* truncate(2) and fallocate(2) subtypes */
1818 enum cl_setattr_subtype sa_subtype;
1819 /* The following are used for fallocate(2) */
1821 loff_t sa_falloc_offset;
1822 loff_t sa_falloc_end;
1823 uid_t sa_falloc_uid;
1824 gid_t sa_falloc_gid;
1825 __u32 sa_falloc_projid;
1827 struct cl_data_version_io {
1828 u64 dv_data_version;
1829 u32 dv_layout_version;
1832 struct cl_fault_io {
1833 /** page index within file. */
1835 /** bytes valid byte on a faulted page. */
1837 /** writable page? for nopage() only */
1839 /** page of an executable? */
1841 /** page_mkwrite() */
1843 /** resulting page */
1844 struct cl_page *ft_page;
1846 struct cl_fsync_io {
1849 /** file system level fid */
1850 struct lu_fid *fi_fid;
1851 enum cl_fsync_mode fi_mode;
1852 /* how many pages were written/discarded */
1853 unsigned int fi_nr_written;
1855 struct cl_ladvise_io {
1858 /** file system level fid */
1859 struct lu_fid *li_fid;
1860 enum lu_ladvise_type li_advice;
1863 struct cl_lseek_io {
1869 time64_t lm_next_rpc_time;
1872 struct cl_2queue ci_queue;
1875 unsigned int ci_continue:1,
1877 * This io has held grouplock, to inform sublayers that
1878 * don't do lockless i/o.
1882 * The whole IO need to be restarted because layout has been changed
1886 * to not refresh layout - the IO issuer knows that the layout won't
1887 * change(page operations, layout change causes all page to be
1888 * discarded), or it doesn't matter if it changes(sync).
1892 * Need MDS intervention to complete a write.
1893 * Write intent is required for the following cases:
1894 * 1. component being written is not initialized, or
1895 * 2. the mirrored files are NOT in WRITE_PENDING state.
1897 ci_need_write_intent:1,
1899 * Check if layout changed after the IO finishes. Mainly for HSM
1900 * requirement. If IO occurs to openning files, it doesn't need to
1901 * verify layout because HSM won't release openning files.
1902 * Right now, only two opertaions need to verify layout: glimpse
1907 * file is released, restore has to to be triggered by vvp layer
1909 ci_restore_needed:1,
1914 /* Tell sublayers not to expand LDLM locks requested for this IO */
1915 ci_lock_no_expand:1,
1917 * Set if non-delay RPC should be used for this IO.
1919 * If this file has multiple mirrors, and if the OSTs of the current
1920 * mirror is inaccessible, non-delay RPC would error out quickly so
1921 * that the upper layer can try to access the next mirror.
1925 * Set if IO is triggered by async workqueue readahead.
1927 ci_async_readahead:1,
1929 * Ignore lockless and do normal locking for this io.
1933 * Set if we've tried all mirrors for this read IO, if it's not set,
1934 * the read IO will check to-be-read OSCs' status, and make fast-switch
1935 * another mirror if some of the OSTs are not healthy.
1937 ci_tried_all_mirrors:1,
1939 * Random read hints, readahead will be disabled.
1943 * Sequential read hints.
1947 * Do parallel (async) submission of DIO RPCs. Note DIO is still sync
1948 * to userspace, only the RPCs are submitted async, then waited for at
1949 * the llite layer before returning.
1953 * Bypass quota check
1955 unsigned ci_noquota:1,
1957 * io_uring direct IO with flags IOCB_NOWAIT.
1961 * How many times the read has retried before this one.
1962 * Set by the top level and consumed by the LOV.
1964 unsigned ci_ndelay_tried;
1966 * Designated mirror index for this I/O.
1968 unsigned ci_designated_mirror;
1970 * Number of pages owned by this IO. For invariant checking.
1972 unsigned ci_owned_nr;
1974 * Range of write intent. Valid if ci_need_write_intent is set.
1976 struct lu_extent ci_write_intent;
1982 * Per-transfer attributes.
1984 struct cl_req_attr {
1985 enum cl_req_type cra_type;
1987 struct cl_page *cra_page;
1988 /** Generic attributes for the server consumption. */
1989 struct obdo *cra_oa;
1991 char cra_jobid[LUSTRE_JOBID_SIZE];
1994 enum cache_stats_item {
1995 /** how many cache lookups were performed */
1997 /** how many times cache lookup resulted in a hit */
1999 /** how many entities are in the cache right now */
2001 /** how many entities in the cache are actively used (and cannot be
2002 * evicted) right now */
2004 /** how many entities were created at all */
2009 #define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
2012 * Stats for a generic cache (similar to inode, lu_object, etc. caches).
2014 struct cache_stats {
2015 const char *cs_name;
2016 atomic_t cs_stats[CS_NR];
2019 /** These are not exported so far */
2020 void cache_stats_init (struct cache_stats *cs, const char *name);
2023 * Client-side site. This represents particular client stack. "Global"
2024 * variables should (directly or indirectly) be added here to allow multiple
2025 * clients to co-exist in the single address space.
2028 struct lu_site cs_lu;
2030 * Statistical counters. Atomics do not scale, something better like
2031 * per-cpu counters is needed.
2033 * These are exported as /proc/fs/lustre/llite/.../site
2035 * When interpreting keep in mind that both sub-locks (and sub-pages)
2036 * and top-locks (and top-pages) are accounted here.
2038 struct cache_stats cs_pages;
2039 atomic_t cs_pages_state[CPS_NR];
2042 int cl_site_init(struct cl_site *s, struct cl_device *top);
2043 void cl_site_fini(struct cl_site *s);
2044 void cl_stack_fini(const struct lu_env *env, struct cl_device *cl);
2047 * Output client site statistical counters into a buffer. Suitable for
2048 * ll_rd_*()-style functions.
2050 int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
2055 * Type conversion and accessory functions.
2059 static inline struct cl_site *lu2cl_site(const struct lu_site *site)
2061 return container_of(site, struct cl_site, cs_lu);
2064 static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
2066 LASSERT(d == NULL || IS_ERR(d) || lu_device_is_cl(d));
2067 return container_of_safe(d, struct cl_device, cd_lu_dev);
2070 static inline struct lu_device *cl2lu_dev(struct cl_device *d)
2072 return &d->cd_lu_dev;
2075 static inline struct cl_object *lu2cl(const struct lu_object *o)
2077 LASSERT(o == NULL || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
2078 return container_of_safe(o, struct cl_object, co_lu);
2081 static inline const struct cl_object_conf *
2082 lu2cl_conf(const struct lu_object_conf *conf)
2084 return container_of_safe(conf, struct cl_object_conf, coc_lu);
2087 static inline struct cl_object *cl_object_next(const struct cl_object *obj)
2089 return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL;
2092 static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
2094 return container_of_safe(h, struct cl_object_header, coh_lu);
2097 static inline struct cl_site *cl_object_site(const struct cl_object *obj)
2099 return lu2cl_site(obj->co_lu.lo_dev->ld_site);
2103 struct cl_object_header *cl_object_header(const struct cl_object *obj)
2105 return luh2coh(obj->co_lu.lo_header);
2108 static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
2110 return lu_device_init(&d->cd_lu_dev, t);
2113 static inline void cl_device_fini(struct cl_device *d)
2115 lu_device_fini(&d->cd_lu_dev);
2118 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
2119 struct cl_object *obj,
2120 const struct cl_page_operations *ops);
2121 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
2122 struct cl_object *obj,
2123 const struct cl_lock_operations *ops);
2124 void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
2125 struct cl_object *obj, const struct cl_io_operations *ops);
2128 /** \defgroup cl_object cl_object
2130 struct cl_object *cl_object_top (struct cl_object *o);
2131 struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
2132 const struct lu_fid *fid,
2133 const struct cl_object_conf *c);
2135 int cl_object_header_init(struct cl_object_header *h);
2136 void cl_object_header_fini(struct cl_object_header *h);
2137 void cl_object_put (const struct lu_env *env, struct cl_object *o);
2138 void cl_object_get (struct cl_object *o);
2139 void cl_object_attr_lock (struct cl_object *o);
2140 void cl_object_attr_unlock(struct cl_object *o);
2141 int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
2142 struct cl_attr *attr);
2143 int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
2144 const struct cl_attr *attr, unsigned valid);
2145 int cl_object_glimpse (const struct lu_env *env, struct cl_object *obj,
2146 struct ost_lvb *lvb);
2147 int cl_conf_set (const struct lu_env *env, struct cl_object *obj,
2148 const struct cl_object_conf *conf);
2149 int cl_object_prune (const struct lu_env *env, struct cl_object *obj);
2150 void cl_object_kill (const struct lu_env *env, struct cl_object *obj);
2151 int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj,
2152 struct lov_user_md __user *lum, size_t size);
2153 int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj,
2154 struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap,
2156 int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj,
2157 struct cl_layout *cl);
2158 loff_t cl_object_maxbytes(struct cl_object *obj);
2159 int cl_object_flush(const struct lu_env *env, struct cl_object *obj,
2160 struct ldlm_lock *lock);
2164 * Returns true, iff \a o0 and \a o1 are slices of the same object.
2166 static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
2168 return cl_object_header(o0) == cl_object_header(o1);
2171 static inline void cl_object_page_init(struct cl_object *clob, int size)
2173 clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
2174 cl_object_header(clob)->coh_page_bufsize += cfs_size_round(size);
2175 WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
2178 static inline void *cl_object_page_slice(struct cl_object *clob,
2179 struct cl_page *page)
2181 return (void *)((char *)page + clob->co_slice_off);
2185 * Return refcount of cl_object.
2187 static inline int cl_object_refc(struct cl_object *clob)
2189 struct lu_object_header *header = clob->co_lu.lo_header;
2190 return atomic_read(&header->loh_ref);
2195 /** \defgroup cl_page cl_page
2197 struct cl_page *cl_page_find (const struct lu_env *env,
2198 struct cl_object *obj,
2199 pgoff_t idx, struct page *vmpage,
2200 enum cl_page_type type);
2201 struct cl_page *cl_page_alloc (const struct lu_env *env,
2202 struct cl_object *o, pgoff_t ind,
2203 struct page *vmpage,
2204 enum cl_page_type type);
2205 void cl_page_get (struct cl_page *page);
2206 void cl_page_put (const struct lu_env *env,
2207 struct cl_page *page);
2208 void cl_pagevec_put (const struct lu_env *env,
2209 struct cl_page *page,
2210 struct pagevec *pvec);
2211 void cl_page_print (const struct lu_env *env, void *cookie,
2212 lu_printer_t printer,
2213 const struct cl_page *pg);
2214 void cl_page_header_print(const struct lu_env *env, void *cookie,
2215 lu_printer_t printer,
2216 const struct cl_page *pg);
2217 struct cl_page *cl_vmpage_page (struct page *vmpage, struct cl_object *obj);
2218 struct cl_page *cl_page_top (struct cl_page *page);
2220 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
2221 const struct lu_device_type *dtype);
2226 * Functions dealing with the ownership of page by io.
2230 int cl_page_own (const struct lu_env *env,
2231 struct cl_io *io, struct cl_page *page);
2232 int cl_page_own_try (const struct lu_env *env,
2233 struct cl_io *io, struct cl_page *page);
2234 void cl_page_assume (const struct lu_env *env,
2235 struct cl_io *io, struct cl_page *page);
2236 void cl_page_unassume (const struct lu_env *env,
2237 struct cl_io *io, struct cl_page *pg);
2238 void cl_page_disown (const struct lu_env *env,
2239 struct cl_io *io, struct cl_page *page);
2240 int cl_page_is_owned (const struct cl_page *pg, const struct cl_io *io);
2247 * Functions dealing with the preparation of a page for a transfer, and
2248 * tracking transfer state.
2251 int cl_page_prep (const struct lu_env *env, struct cl_io *io,
2252 struct cl_page *pg, enum cl_req_type crt);
2253 void cl_page_completion (const struct lu_env *env,
2254 struct cl_page *pg, enum cl_req_type crt, int ioret);
2255 int cl_page_make_ready (const struct lu_env *env, struct cl_page *pg,
2256 enum cl_req_type crt);
2257 int cl_page_cache_add (const struct lu_env *env, struct cl_io *io,
2258 struct cl_page *pg, enum cl_req_type crt);
2259 void cl_page_clip (const struct lu_env *env, struct cl_page *pg,
2261 int cl_page_flush (const struct lu_env *env, struct cl_io *io,
2262 struct cl_page *pg);
2268 * \name helper routines
2269 * Functions to discard, delete and export a cl_page.
2272 void cl_page_discard(const struct lu_env *env, struct cl_io *io,
2273 struct cl_page *pg);
2274 void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
2275 void cl_page_touch(const struct lu_env *env, const struct cl_page *pg,
2277 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx);
2278 pgoff_t cl_index(const struct cl_object *obj, loff_t offset);
2279 size_t cl_page_size(const struct cl_object *obj);
2281 void cl_lock_print(const struct lu_env *env, void *cookie,
2282 lu_printer_t printer, const struct cl_lock *lock);
2283 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2284 lu_printer_t printer,
2285 const struct cl_lock_descr *descr);
2289 * Data structure managing a client's cached pages. A count of
2290 * "unstable" pages is maintained, and an LRU of clean pages is
2291 * maintained. "unstable" pages are pages pinned by the ptlrpc
2292 * layer for recovery purposes.
2294 struct cl_client_cache {
2296 * # of client cache refcount
2297 * # of users (OSCs) + 2 (held by llite and lov)
2301 * # of threads are doing shrinking
2303 unsigned int ccc_lru_shrinkers;
2305 * # of LRU entries available
2307 atomic_long_t ccc_lru_left;
2309 * List of entities(OSCs) for this LRU cache
2311 struct list_head ccc_lru;
2313 * Max # of LRU entries
2315 unsigned long ccc_lru_max;
2317 * Lock to protect ccc_lru list
2319 spinlock_t ccc_lru_lock;
2321 * Set if unstable check is enabled
2323 unsigned int ccc_unstable_check:1;
2325 * # of unstable pages for this mount point
2327 atomic_long_t ccc_unstable_nr;
2329 * Waitq for awaiting unstable pages to reach zero.
2330 * Used at umounting time and signaled on BRW commit
2332 wait_queue_head_t ccc_unstable_waitq;
2334 * Serialize max_cache_mb write operation
2336 struct mutex ccc_max_cache_mb_lock;
2339 * cl_cache functions
2341 struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
2342 void cl_cache_incref(struct cl_client_cache *cache);
2343 void cl_cache_decref(struct cl_client_cache *cache);
2347 /** \defgroup cl_lock cl_lock
2349 int cl_lock_request(const struct lu_env *env, struct cl_io *io,
2350 struct cl_lock *lock);
2351 int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
2352 const struct cl_io *io);
2353 void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
2354 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
2355 const struct lu_device_type *dtype);
2356 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
2358 int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
2359 struct cl_lock *lock, struct cl_sync_io *anchor);
2360 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
2364 /** \defgroup cl_io cl_io
2367 int cl_io_init (const struct lu_env *env, struct cl_io *io,
2368 enum cl_io_type iot, struct cl_object *obj);
2369 int cl_io_sub_init (const struct lu_env *env, struct cl_io *io,
2370 enum cl_io_type iot, struct cl_object *obj);
2371 int cl_io_rw_init (const struct lu_env *env, struct cl_io *io,
2372 enum cl_io_type iot, loff_t pos, size_t count);
2373 int cl_io_loop (const struct lu_env *env, struct cl_io *io);
2375 void cl_io_fini (const struct lu_env *env, struct cl_io *io);
2376 int cl_io_iter_init (const struct lu_env *env, struct cl_io *io);
2377 void cl_io_iter_fini (const struct lu_env *env, struct cl_io *io);
2378 int cl_io_lock (const struct lu_env *env, struct cl_io *io);
2379 void cl_io_unlock (const struct lu_env *env, struct cl_io *io);
2380 int cl_io_start (const struct lu_env *env, struct cl_io *io);
2381 void cl_io_end (const struct lu_env *env, struct cl_io *io);
2382 int cl_io_lock_add (const struct lu_env *env, struct cl_io *io,
2383 struct cl_io_lock_link *link);
2384 int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
2385 struct cl_lock_descr *descr);
2386 int cl_io_submit_rw (const struct lu_env *env, struct cl_io *io,
2387 enum cl_req_type iot, struct cl_2queue *queue);
2388 int cl_io_submit_sync (const struct lu_env *env, struct cl_io *io,
2389 enum cl_req_type iot, struct cl_2queue *queue,
2391 int cl_io_commit_async (const struct lu_env *env, struct cl_io *io,
2392 struct cl_page_list *queue, int from, int to,
2394 void cl_io_extent_release (const struct lu_env *env, struct cl_io *io);
2395 int cl_io_lru_reserve(const struct lu_env *env, struct cl_io *io,
2396 loff_t pos, size_t bytes);
2397 int cl_io_read_ahead (const struct lu_env *env, struct cl_io *io,
2398 pgoff_t start, struct cl_read_ahead *ra);
2399 void cl_io_rw_advance (const struct lu_env *env, struct cl_io *io,
2403 * True, iff \a io is an O_APPEND write(2).
2405 static inline int cl_io_is_append(const struct cl_io *io)
2407 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
2410 static inline int cl_io_is_sync_write(const struct cl_io *io)
2412 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
2415 static inline int cl_io_is_mkwrite(const struct cl_io *io)
2417 return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
2421 * True, iff \a io is a truncate(2).
2423 static inline int cl_io_is_trunc(const struct cl_io *io)
2425 return io->ci_type == CIT_SETATTR &&
2426 (io->u.ci_setattr.sa_avalid & ATTR_SIZE) &&
2427 (io->u.ci_setattr.sa_subtype != CL_SETATTR_FALLOCATE);
2430 static inline int cl_io_is_fallocate(const struct cl_io *io)
2432 return (io->ci_type == CIT_SETATTR) &&
2433 (io->u.ci_setattr.sa_subtype == CL_SETATTR_FALLOCATE);
2436 struct cl_io *cl_io_top(struct cl_io *io);
2438 void cl_io_print(const struct lu_env *env, void *cookie,
2439 lu_printer_t printer, const struct cl_io *io);
2441 #define CL_IO_SLICE_CLEAN(foo_io, base) \
2443 typeof(foo_io) __foo_io = (foo_io); \
2445 memset(&__foo_io->base, 0, \
2446 sizeof(*__foo_io) - offsetof(typeof(*__foo_io), base)); \
2451 /** \defgroup cl_page_list cl_page_list
2455 * Last page in the page list.
2457 static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
2459 LASSERT(plist->pl_nr > 0);
2460 return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
2463 static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
2465 LASSERT(plist->pl_nr > 0);
2466 return list_first_entry(&plist->pl_pages, struct cl_page, cp_batch);
2470 * Iterate over pages in a page list.
2472 #define cl_page_list_for_each(page, list) \
2473 list_for_each_entry((page), &(list)->pl_pages, cp_batch)
2476 * Iterate over pages in a page list, taking possible removals into account.
2478 #define cl_page_list_for_each_safe(page, temp, list) \
2479 list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
2481 void cl_page_list_init(struct cl_page_list *plist);
2482 void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page,
2484 void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src,
2485 struct cl_page *page);
2486 void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
2487 struct cl_page *page);
2488 void cl_page_list_splice(struct cl_page_list *list,
2489 struct cl_page_list *head);
2490 void cl_page_list_del(const struct lu_env *env,
2491 struct cl_page_list *plist, struct cl_page *page);
2492 void cl_page_list_disown(const struct lu_env *env,
2493 struct cl_page_list *plist);
2494 void cl_page_list_assume(const struct lu_env *env,
2495 struct cl_io *io, struct cl_page_list *plist);
2496 void cl_page_list_discard(const struct lu_env *env,
2497 struct cl_io *io, struct cl_page_list *plist);
2498 void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist);
2500 void cl_2queue_init(struct cl_2queue *queue);
2501 void cl_2queue_disown(const struct lu_env *env, struct cl_2queue *queue);
2502 void cl_2queue_assume(const struct lu_env *env, struct cl_io *io,
2503 struct cl_2queue *queue);
2504 void cl_2queue_discard(const struct lu_env *env, struct cl_io *io,
2505 struct cl_2queue *queue);
2506 void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue);
2507 void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
2509 /** @} cl_page_list */
2511 void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
2512 struct cl_req_attr *attr);
2514 /** \defgroup cl_sync_io cl_sync_io
2521 typedef void (cl_sync_io_end_t)(const struct lu_env *, struct cl_sync_io *);
2523 void cl_sync_io_init_notify(struct cl_sync_io *anchor, int nr, void *dio_aio,
2524 cl_sync_io_end_t *end);
2526 int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
2528 void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
2530 int cl_sync_io_wait_recycle(const struct lu_env *env, struct cl_sync_io *anchor,
2531 long timeout, int ioret);
2532 struct cl_dio_aio *cl_dio_aio_alloc(struct kiocb *iocb, struct cl_object *obj,
2534 struct cl_sub_dio *cl_sub_dio_alloc(struct cl_dio_aio *ll_aio, bool nofree);
2535 void cl_dio_aio_free(const struct lu_env *env, struct cl_dio_aio *aio,
2537 void cl_sub_dio_free(struct cl_sub_dio *sdio, bool nofree);
2538 static inline void cl_sync_io_init(struct cl_sync_io *anchor, int nr)
2540 cl_sync_io_init_notify(anchor, nr, NULL, NULL);
2544 * Anchor for synchronous transfer. This is allocated on a stack by thread
2545 * doing synchronous transfer, and a pointer to this structure is set up in
2546 * every page submitted for transfer. Transfer completion routine updates
2547 * anchor and wakes up waiting thread when transfer is complete.
2550 /** number of pages yet to be transferred. */
2551 atomic_t csi_sync_nr;
2554 /** completion to be signaled when transfer is complete. */
2555 wait_queue_head_t csi_waitq;
2556 /** callback to invoke when this IO is finished */
2557 cl_sync_io_end_t *csi_end_io;
2558 /* private pointer for an associated DIO/AIO */
2562 /** direct IO pages */
2563 struct ll_dio_pages {
2565 * page array to be written. we don't support
2566 * partial pages except the last one.
2568 struct page **ldp_pages;
2569 /** # of pages in the array. */
2571 /* the file offset of the first page. */
2572 loff_t ldp_file_offset;
2575 /* Top level struct used for AIO and DIO */
2577 struct cl_sync_io cda_sync;
2578 struct cl_object *cda_obj;
2579 struct kiocb *cda_iocb;
2581 unsigned cda_no_aio_complete:1,
2585 /* Sub-dio used for splitting DIO (and AIO, because AIO is DIO) according to
2586 * the layout/striping, so we can do parallel submit of DIO RPCs
2589 struct cl_sync_io csd_sync;
2590 struct cl_page_list csd_pages;
2592 struct cl_dio_aio *csd_ll_aio;
2593 struct ll_dio_pages csd_dio_pages;
2594 unsigned csd_no_free:1;
2596 #if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW) || \
2597 defined(HAVE_DIRECTIO_2ARGS)
2598 #define HAVE_DIO_ITER 1
2601 void ll_release_user_pages(struct page **pages, int npages);
2603 /** @} cl_sync_io */
2605 /** \defgroup cl_env cl_env
2607 * lu_env handling for a client.
2609 * lu_env is an environment within which lustre code executes. Its major part
2610 * is lu_context---a fast memory allocation mechanism that is used to conserve
2611 * precious kernel stack space. Originally lu_env was designed for a server,
2614 * - there is a (mostly) fixed number of threads, and
2616 * - call chains have no non-lustre portions inserted between lustre code.
2618 * On a client both these assumtpion fails, because every user thread can
2619 * potentially execute lustre code as part of a system call, and lustre calls
2620 * into VFS or MM that call back into lustre.
2622 * To deal with that, cl_env wrapper functions implement the following
2625 * - allocation and destruction of environment is amortized by caching no
2626 * longer used environments instead of destroying them;
2628 * \see lu_env, lu_context, lu_context_key
2631 struct lu_env *cl_env_get(__u16 *refcheck);
2632 struct lu_env *cl_env_alloc(__u16 *refcheck, __u32 tags);
2633 void cl_env_put(struct lu_env *env, __u16 *refcheck);
2634 unsigned cl_env_cache_purge(unsigned nr);
2635 struct lu_env *cl_env_percpu_get(void);
2636 void cl_env_percpu_put(struct lu_env *env);
2643 void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr);
2644 void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
2646 struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
2647 struct lu_device_type *ldt,
2648 struct lu_device *next);
2651 int cl_global_init(void);
2652 void cl_global_fini(void);
2654 #endif /* _LINUX_CL_OBJECT_H */