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26 * Copyright (c) 2011, 2017, Intel Corporation.
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 <libcfs/linux/linux-misc.h>
102 #include <lustre_dlm.h>
112 struct cl_page_slice;
114 struct cl_lock_slice;
116 struct cl_lock_operations;
117 struct cl_page_operations;
125 * Device in the client stack.
127 * \see vvp_device, lov_device, lovsub_device, osc_device
131 struct lu_device cd_lu_dev;
134 /** \addtogroup cl_object cl_object
137 * "Data attributes" of cl_object. Data attributes can be updated
138 * independently for a sub-object, and top-object's attributes are calculated
139 * from sub-objects' ones.
142 /** Object size, in bytes */
145 unsigned int cat_kms_valid:1;
147 * Known minimal size, in bytes.
149 * This is only valid when at least one DLM lock is held.
152 /** Modification time. Measured in seconds since epoch. */
154 /** Access time. Measured in seconds since epoch. */
156 /** Change time. Measured in seconds since epoch. */
159 * Blocks allocated to this cl_object on the server file system.
161 * \todo XXX An interface for block size is needed.
165 * User identifier for quota purposes.
169 * Group identifier for quota purposes.
173 /* nlink of the directory */
176 /* Project identifier for quota purpose. */
181 * Fields in cl_attr that are being set.
196 * Sub-class of lu_object with methods common for objects on the client
199 * cl_object: represents a regular file system object, both a file and a
200 * stripe. cl_object is based on lu_object: it is identified by a fid,
201 * layered, cached, hashed, and lrued. Important distinction with the server
202 * side, where md_object and dt_object are used, is that cl_object "fans out"
203 * at the lov/sns level: depending on the file layout, single file is
204 * represented as a set of "sub-objects" (stripes). At the implementation
205 * level, struct lov_object contains an array of cl_objects. Each sub-object
206 * is a full-fledged cl_object, having its fid, living in the lru and hash
209 * This leads to the next important difference with the server side: on the
210 * client, it's quite usual to have objects with the different sequence of
211 * layers. For example, typical top-object is composed of the following
217 * whereas its sub-objects are composed of
222 * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep
223 * track of the object-subobject relationship.
225 * Sub-objects are not cached independently: when top-object is about to
226 * be discarded from the memory, all its sub-objects are torn-down and
229 * \see vvp_object, lov_object, lovsub_object, osc_object
233 struct lu_object co_lu;
234 /** per-object-layer operations */
235 const struct cl_object_operations *co_ops;
236 /** offset of page slice in cl_page buffer */
241 * Description of the client object configuration. This is used for the
242 * creation of a new client object that is identified by a more state than
245 struct cl_object_conf {
247 struct lu_object_conf coc_lu;
250 * Object layout. This is consumed by lov.
252 struct lu_buf coc_layout;
254 * Description of particular stripe location in the
255 * cluster. This is consumed by osc.
257 struct lov_oinfo *coc_oinfo;
260 * VFS inode. This is consumed by vvp.
262 struct inode *coc_inode;
264 * Layout lock handle.
266 struct ldlm_lock *coc_lock;
269 * Operation to handle layout, OBJECT_CONF_XYZ.
275 /** configure layout, set up a new stripe, must be called while
276 * holding layout lock. */
278 /** invalidate the current stripe configuration due to losing
280 OBJECT_CONF_INVALIDATE = 1,
281 /** wait for old layout to go away so that new layout can be
287 CL_LAYOUT_GEN_NONE = (u32)-2, /* layout lock was cancelled */
288 CL_LAYOUT_GEN_EMPTY = (u32)-1, /* for empty layout */
292 /** the buffer to return the layout in lov_mds_md format. */
293 struct lu_buf cl_buf;
294 /** size of layout in lov_mds_md format. */
296 /** Layout generation. */
298 /** whether layout is a composite one */
299 bool cl_is_composite;
300 /** Whether layout is a HSM released one */
314 * Operations implemented for each cl object layer.
316 * \see vvp_ops, lov_ops, lovsub_ops, osc_ops
318 struct cl_object_operations {
320 * Initialize page slice for this layer. Called top-to-bottom through
321 * every object layer when a new cl_page is instantiated. Layer
322 * keeping private per-page data, or requiring its own page operations
323 * vector should allocate these data here, and attach then to the page
324 * by calling cl_page_slice_add(). \a vmpage is locked (in the VM
327 * \retval NULL success.
329 * \retval ERR_PTR(errno) failure code.
331 * \retval valid-pointer pointer to already existing referenced page
332 * to be used instead of newly created.
334 int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj,
335 struct cl_page *page, pgoff_t index);
337 * Initialize lock slice for this layer. Called top-to-bottom through
338 * every object layer when a new cl_lock is instantiated. Layer
339 * keeping private per-lock data, or requiring its own lock operations
340 * vector should allocate these data here, and attach then to the lock
341 * by calling cl_lock_slice_add(). Mandatory.
343 int (*coo_lock_init)(const struct lu_env *env,
344 struct cl_object *obj, struct cl_lock *lock,
345 const struct cl_io *io);
347 * Initialize io state for a given layer.
349 * called top-to-bottom once per io existence to initialize io
350 * state. If layer wants to keep some state for this type of io, it
351 * has to embed struct cl_io_slice in lu_env::le_ses, and register
352 * slice with cl_io_slice_add(). It is guaranteed that all threads
353 * participating in this io share the same session.
355 int (*coo_io_init)(const struct lu_env *env,
356 struct cl_object *obj, struct cl_io *io);
358 * Fill portion of \a attr that this layer controls. This method is
359 * called top-to-bottom through all object layers.
361 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
363 * \return 0: to continue
364 * \return +ve: to stop iterating through layers (but 0 is returned
365 * from enclosing cl_object_attr_get())
366 * \return -ve: to signal error
368 int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj,
369 struct cl_attr *attr);
373 * \a valid is a bitmask composed from enum #cl_attr_valid, and
374 * indicating what attributes are to be set.
376 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
378 * \return the same convention as for
379 * cl_object_operations::coo_attr_get() is used.
381 int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj,
382 const struct cl_attr *attr, unsigned valid);
384 * Mark the inode dirty. By this way, the inode will add into the
385 * writeback list of the corresponding @bdi_writeback, and then it will
386 * defer to write out the dirty pages to OSTs via the kernel writeback
389 void (*coo_dirty_for_sync)(const struct lu_env *env,
390 struct cl_object *obj);
392 * Update object configuration. Called top-to-bottom to modify object
395 * XXX error conditions and handling.
397 int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj,
398 const struct cl_object_conf *conf);
400 * Glimpse ast. Executed when glimpse ast arrives for a lock on this
401 * object. Layers are supposed to fill parts of \a lvb that will be
402 * shipped to the glimpse originator as a glimpse result.
404 * \see vvp_object_glimpse(), lovsub_object_glimpse(),
405 * \see osc_object_glimpse()
407 int (*coo_glimpse)(const struct lu_env *env,
408 const struct cl_object *obj, struct ost_lvb *lvb);
410 * Object prune method. Called when the layout is going to change on
411 * this object, therefore each layer has to clean up their cache,
412 * mainly pages and locks.
414 int (*coo_prune)(const struct lu_env *env, struct cl_object *obj);
416 * Object getstripe method.
418 int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj,
419 struct lov_user_md __user *lum, size_t size);
421 * Get FIEMAP mapping from the object.
423 int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj,
424 struct ll_fiemap_info_key *fmkey,
425 struct fiemap *fiemap, size_t *buflen);
427 * Get layout and generation of the object.
429 int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj,
430 struct cl_layout *layout);
432 * Get maximum size of the object.
434 loff_t (*coo_maxbytes)(struct cl_object *obj);
436 * Set request attributes.
438 void (*coo_req_attr_set)(const struct lu_env *env,
439 struct cl_object *obj,
440 struct cl_req_attr *attr);
442 * Flush \a obj data corresponding to \a lock. Used for DoM
443 * locks in llite's cancelling blocking ast callback.
445 int (*coo_object_flush)(const struct lu_env *env,
446 struct cl_object *obj,
447 struct ldlm_lock *lock);
449 * operate upon inode. Used in LOV to lock/unlock inode from vvp layer.
451 int (*coo_inode_ops)(const struct lu_env *env, struct cl_object *obj,
452 enum coo_inode_opc opc, void *data);
456 * Extended header for client object.
458 struct cl_object_header {
459 /** Standard lu_object_header. cl_object::co_lu::lo_header points
461 struct lu_object_header coh_lu;
464 * Parent object. It is assumed that an object has a well-defined
465 * parent, but not a well-defined child (there may be multiple
466 * sub-objects, for the same top-object). cl_object_header::coh_parent
467 * field allows certain code to be written generically, without
468 * limiting possible cl_object layouts unduly.
470 struct cl_object_header *coh_parent;
472 * Protects consistency between cl_attr of parent object and
473 * attributes of sub-objects, that the former is calculated ("merged")
476 * \todo XXX this can be read/write lock if needed.
478 spinlock_t coh_attr_guard;
480 * Size of cl_page + page slices
482 unsigned short coh_page_bufsize;
484 * Number of objects above this one: 0 for a top-object, 1 for its
487 unsigned char coh_nesting;
491 * Helper macro: iterate over all layers of the object \a obj, assigning every
492 * layer top-to-bottom to \a slice.
494 #define cl_object_for_each(slice, obj) \
495 list_for_each_entry((slice), \
496 &(obj)->co_lu.lo_header->loh_layers,\
500 * Helper macro: iterate over all layers of the object \a obj, assigning every
501 * layer bottom-to-top to \a slice.
503 #define cl_object_for_each_reverse(slice, obj) \
504 list_for_each_entry_reverse((slice), \
505 &(obj)->co_lu.lo_header->loh_layers,\
510 #define CL_PAGE_EOF ((pgoff_t)~0ull)
512 /** \addtogroup cl_page cl_page
516 * Layered client page.
518 * cl_page: represents a portion of a file, cached in the memory. All pages
519 * of the given file are of the same size, and are kept in the radix tree
520 * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects
521 * of the top-level file object are first class cl_objects, they have their
522 * own radix trees of pages and hence page is implemented as a sequence of
523 * struct cl_pages's, linked into double-linked list through
524 * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the
525 * corresponding radix tree at the corresponding logical offset.
527 * cl_page is associated with VM page of the hosting environment (struct
528 * page in Linux kernel, for example), struct page. It is assumed, that this
529 * association is implemented by one of cl_page layers (top layer in the
530 * current design) that
532 * - intercepts per-VM-page call-backs made by the environment (e.g.,
535 * - translates state (page flag bits) and locking between lustre and
538 * The association between cl_page and struct page is immutable and
539 * established when cl_page is created.
541 * cl_page can be "owned" by a particular cl_io (see below), guaranteeing
542 * this io an exclusive access to this page w.r.t. other io attempts and
543 * various events changing page state (such as transfer completion, or
544 * eviction of the page from the memory). Note, that in general cl_io
545 * cannot be identified with a particular thread, and page ownership is not
546 * exactly equal to the current thread holding a lock on the page. Layer
547 * implementing association between cl_page and struct page has to implement
548 * ownership on top of available synchronization mechanisms.
550 * While lustre client maintains the notion of an page ownership by io,
551 * hosting MM/VM usually has its own page concurrency control
552 * mechanisms. For example, in Linux, page access is synchronized by the
553 * per-page PG_locked bit-lock, and generic kernel code (generic_file_*())
554 * takes care to acquire and release such locks as necessary around the
555 * calls to the file system methods (->readpage(), ->prepare_write(),
556 * ->commit_write(), etc.). This leads to the situation when there are two
557 * different ways to own a page in the client:
559 * - client code explicitly and voluntary owns the page (cl_page_own());
561 * - VM locks a page and then calls the client, that has "to assume"
562 * the ownership from the VM (cl_page_assume()).
564 * Dual methods to release ownership are cl_page_disown() and
565 * cl_page_unassume().
567 * cl_page is reference counted (cl_page::cp_ref). When reference counter
568 * drops to 0, the page is returned to the cache, unless it is in
569 * cl_page_state::CPS_FREEING state, in which case it is immediately
572 * The general logic guaranteeing the absence of "existential races" for
573 * pages is the following:
575 * - there are fixed known ways for a thread to obtain a new reference
578 * - by doing a lookup in the cl_object radix tree, protected by the
581 * - by starting from VM-locked struct page and following some
582 * hosting environment method (e.g., following ->private pointer in
583 * the case of Linux kernel), see cl_vmpage_page();
585 * - when the page enters cl_page_state::CPS_FREEING state, all these
586 * ways are severed with the proper synchronization
587 * (cl_page_delete());
589 * - entry into cl_page_state::CPS_FREEING is serialized by the VM page
592 * - no new references to the page in cl_page_state::CPS_FREEING state
593 * are allowed (checked in cl_page_get()).
595 * Together this guarantees that when last reference to a
596 * cl_page_state::CPS_FREEING page is released, it is safe to destroy the
597 * page, as neither references to it can be acquired at that point, nor
600 * cl_page is a state machine. States are enumerated in enum
601 * cl_page_state. Possible state transitions are enumerated in
602 * cl_page_state_set(). State transition process (i.e., actual changing of
603 * cl_page::cp_state field) is protected by the lock on the underlying VM
606 * Linux Kernel implementation.
608 * Binding between cl_page and struct page (which is a typedef for
609 * struct page) is implemented in the vvp layer. cl_page is attached to the
610 * ->private pointer of the struct page, together with the setting of
611 * PG_private bit in page->flags, and acquiring additional reference on the
612 * struct page (much like struct buffer_head, or any similar file system
613 * private data structures).
615 * PG_locked lock is used to implement both ownership and transfer
616 * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}}
617 * states. No additional references are acquired for the duration of the
620 * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where
621 * write-out is "protected" by the special PG_writeback bit.
625 * States of cl_page. cl_page.c assumes particular order here.
627 * The page state machine is rather crude, as it doesn't recognize finer page
628 * states like "dirty" or "up to date". This is because such states are not
629 * always well defined for the whole stack (see, for example, the
630 * implementation of the read-ahead, that hides page up-to-dateness to track
631 * cache hits accurately). Such sub-states are maintained by the layers that
632 * are interested in them.
636 * Page is in the cache, un-owned. Page leaves cached state in the
639 * - [cl_page_state::CPS_OWNED] io comes across the page and
642 * - [cl_page_state::CPS_PAGEOUT] page is dirty, the
643 * req-formation engine decides that it wants to include this page
644 * into an RPC being constructed, and yanks it from the cache;
646 * - [cl_page_state::CPS_FREEING] VM callback is executed to
647 * evict the page form the memory;
649 * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL
653 * Page is exclusively owned by some cl_io. Page may end up in this
654 * state as a result of
656 * - io creating new page and immediately owning it;
658 * - [cl_page_state::CPS_CACHED] io finding existing cached page
661 * - [cl_page_state::CPS_OWNED] io finding existing owned page
662 * and waiting for owner to release the page;
664 * Page leaves owned state in the following cases:
666 * - [cl_page_state::CPS_CACHED] io decides to leave the page in
667 * the cache, doing nothing;
669 * - [cl_page_state::CPS_PAGEIN] io starts read transfer for
672 * - [cl_page_state::CPS_PAGEOUT] io starts immediate write
673 * transfer for this page;
675 * - [cl_page_state::CPS_FREEING] io decides to destroy this
676 * page (e.g., as part of truncate or extent lock cancellation).
678 * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL
682 * Page is being written out, as a part of a transfer. This state is
683 * entered when req-formation logic decided that it wants this page to
684 * be sent through the wire _now_. Specifically, it means that once
685 * this state is achieved, transfer completion handler (with either
686 * success or failure indication) is guaranteed to be executed against
687 * this page independently of any locks and any scheduling decisions
688 * made by the hosting environment (that effectively means that the
689 * page is never put into cl_page_state::CPS_PAGEOUT state "in
690 * advance". This property is mentioned, because it is important when
691 * reasoning about possible dead-locks in the system). The page can
692 * enter this state as a result of
694 * - [cl_page_state::CPS_OWNED] an io requesting an immediate
695 * write-out of this page, or
697 * - [cl_page_state::CPS_CACHED] req-forming engine deciding
698 * that it has enough dirty pages cached to issue a "good"
701 * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer
702 * is completed---it is moved into cl_page_state::CPS_CACHED state.
704 * Underlying VM page is locked for the duration of transfer.
706 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
710 * Page is being read in, as a part of a transfer. This is quite
711 * similar to the cl_page_state::CPS_PAGEOUT state, except that
712 * read-in is always "immediate"---there is no such thing a sudden
713 * construction of read request from cached, presumably not up to date,
716 * Underlying VM page is locked for the duration of transfer.
718 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
722 * Page is being destroyed. This state is entered when client decides
723 * that page has to be deleted from its host object, as, e.g., a part
726 * Once this state is reached, there is no way to escape it.
728 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL
735 /** Host page, the page is from the host inode which the cl_page
739 /** Transient page, the transient cl_page is used to bind a cl_page
740 * to vmpage which is not belonging to the same object of cl_page.
741 * it is used in DirectIO and lockless IO. */
746 #define CP_STATE_BITS 4
747 #define CP_TYPE_BITS 2
748 #define CP_MAX_LAYER 2
751 * Fields are protected by the lock on struct page, except for atomics and
754 * \invariant Data type invariants are in cl_page_invariant(). Basically:
755 * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked
756 * list, consistent with the parent/child pointers in the cl_page::cp_obj and
757 * cl_page::cp_owner (when set).
760 /** Reference counter. */
762 /** layout_entry + stripe index, composed using lov_comp_index() */
763 unsigned int cp_lov_index;
764 /** page->index of the page within the whole file */
765 pgoff_t cp_page_index;
766 /** An object this page is a part of. Immutable after creation. */
767 struct cl_object *cp_obj;
769 struct page *cp_vmpage;
771 * Assigned if doing direct IO, because in this case cp_vmpage is not
772 * a valid page cache page, hence the inode cannot be inferred from
773 * cp_vmpage->mapping->host.
775 struct inode *cp_inode;
776 /** Linkage of pages within group. Pages must be owned */
777 struct list_head cp_batch;
778 /** array of slices offset. Immutable after creation. */
779 unsigned char cp_layer_offset[CP_MAX_LAYER];
780 /** current slice index */
781 unsigned char cp_layer_count:2;
783 * Page state. This field is const to avoid accidental update, it is
784 * modified only internally within cl_page.c. Protected by a VM lock.
786 enum cl_page_state cp_state:CP_STATE_BITS;
788 * Page type. Only CPT_TRANSIENT is used so far. Immutable after
791 enum cl_page_type cp_type:CP_TYPE_BITS;
792 unsigned cp_defer_uptodate:1,
795 /* which slab kmem index this memory allocated from */
796 short int cp_kmem_index;
799 * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned
800 * by sub-io. Protected by a VM lock.
802 struct cl_io *cp_owner;
803 /** List of references to this page, for debugging. */
804 struct lu_ref cp_reference;
805 /** Link to an object, for debugging. */
806 struct lu_ref_link cp_obj_ref;
807 /** Link to a queue, for debugging. */
808 struct lu_ref_link cp_queue_ref;
809 /** Assigned if doing a sync_io */
810 struct cl_sync_io *cp_sync_io;
814 * Per-layer part of cl_page.
816 * \see vvp_page, lov_page, osc_page
818 struct cl_page_slice {
819 struct cl_page *cpl_page;
820 const struct cl_page_operations *cpl_ops;
824 * Lock mode. For the client extent locks.
836 * Requested transfer type.
845 * Per-layer page operations.
847 * Methods taking an \a io argument are for the activity happening in the
848 * context of given \a io. Page is assumed to be owned by that io, except for
851 * \see vvp_page_ops, lov_page_ops, osc_page_ops
853 struct cl_page_operations {
855 * cl_page<->struct page methods. Only one layer in the stack has to
856 * implement these. Current code assumes that this functionality is
857 * provided by the topmost layer, see __cl_page_disown() as an example.
861 * Update file attributes when all we have is this page. Used for tiny
862 * writes to update attributes when we don't have a full cl_io.
864 void (*cpo_page_touch)(const struct lu_env *env,
865 const struct cl_page_slice *slice, size_t to);
871 * Called when page is truncated from the object. Optional.
873 * \see cl_page_discard()
874 * \see vvp_page_discard(), osc_page_discard()
876 void (*cpo_discard)(const struct lu_env *env,
877 const struct cl_page_slice *slice,
880 * Called when page is removed from the cache, and is about to being
881 * destroyed. Optional.
883 * \see cl_page_delete()
884 * \see vvp_page_delete(), osc_page_delete()
886 void (*cpo_delete)(const struct lu_env *env,
887 const struct cl_page_slice *slice);
889 * Optional debugging helper. Prints given page slice.
891 * \see cl_page_print()
893 int (*cpo_print)(const struct lu_env *env,
894 const struct cl_page_slice *slice,
895 void *cookie, lu_printer_t p);
904 * Request type dependent vector of operations.
906 * Transfer operations depend on transfer mode (cl_req_type). To avoid
907 * passing transfer mode to each and every of these methods, and to
908 * avoid branching on request type inside of the methods, separate
909 * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
910 * provided. That is, method invocation usually looks like
912 * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
916 * Completion handler. This is guaranteed to be eventually
917 * fired after cl_page_prep() or cl_page_make_ready() call.
919 * This method can be called in a non-blocking context. It is
920 * guaranteed however, that the page involved and its object
921 * are pinned in memory (and, hence, calling cl_page_put() is
924 * \see cl_page_completion()
926 void (*cpo_completion)(const struct lu_env *env,
927 const struct cl_page_slice *slice,
931 * Tell transfer engine that only [to, from] part of a page should be
934 * This is used for immediate transfers.
936 * \todo XXX this is not very good interface. It would be much better
937 * if all transfer parameters were supplied as arguments to
938 * cl_io_operations::cio_submit() call, but it is not clear how to do
939 * this for page queues.
941 * \see cl_page_clip()
943 void (*cpo_clip)(const struct lu_env *env,
944 const struct cl_page_slice *slice,
947 * Write out a page by kernel. This is only called by ll_writepage
950 * \see cl_page_flush()
952 int (*cpo_flush)(const struct lu_env *env,
953 const struct cl_page_slice *slice,
959 * Helper macro, dumping detailed information about \a page into a log.
961 #define CL_PAGE_DEBUG(mask, env, page, format, ...) \
963 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
964 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
965 cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
966 CDEBUG(mask, format , ## __VA_ARGS__); \
971 * Helper macro, dumping shorter information about \a page into a log.
973 #define CL_PAGE_HEADER(mask, env, page, format, ...) \
975 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
976 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
977 cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
978 CDEBUG(mask, format , ## __VA_ARGS__); \
982 static inline struct page *cl_page_vmpage(const struct cl_page *page)
984 LASSERT(page->cp_vmpage != NULL);
985 return page->cp_vmpage;
988 static inline pgoff_t cl_page_index(const struct cl_page *cp)
990 return cl_page_vmpage(cp)->index;
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 (refcount_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)
1015 /** \addtogroup cl_lock cl_lock
1019 * Extent locking on the client.
1023 * The locking model of the new client code is built around
1027 * data-type representing an extent lock on a regular file. cl_lock is a
1028 * layered object (much like cl_object and cl_page), it consists of a header
1029 * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
1030 * cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
1032 * Typical cl_lock consists of one layer:
1034 * - lov_lock (lov specific data).
1036 * lov_lock contains an array of sub-locks. Each of these sub-locks is a
1037 * normal cl_lock: it has a header (struct cl_lock) and a list of layers:
1041 * Each sub-lock is associated with a cl_object (representing stripe
1042 * sub-object or the file to which top-level cl_lock is associated to), and is
1043 * linked into that cl_object::coh_locks. In this respect cl_lock is similar to
1044 * cl_object (that at lov layer also fans out into multiple sub-objects), and
1045 * is different from cl_page, that doesn't fan out (there is usually exactly
1046 * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
1047 * a "top-lock" and its lovsub-osc portion a "sub-lock".
1051 * cl_lock is a cacheless data container for the requirements of locks to
1052 * complete the IO. cl_lock is created before I/O starts and destroyed when the
1055 * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
1056 * to cl_lock at OSC layer. LDLM lock is still cacheable.
1058 * INTERFACE AND USAGE
1060 * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
1061 * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
1062 * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
1063 * consists of multiple sub cl_locks, each sub locks will be enqueued
1064 * correspondingly. At OSC layer, the lock enqueue request will tend to reuse
1065 * cached LDLM lock; otherwise a new LDLM lock will have to be requested from
1068 * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
1069 * method will be called for each layer to release the resource held by this
1070 * lock. At OSC layer, the reference count of LDLM lock, which is held at
1071 * clo_enqueue time, is released.
1073 * LDLM lock can only be canceled if there is no cl_lock using it.
1075 * Overall process of the locking during IO operation is as following:
1077 * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
1078 * is called on each layer. Responsibility of this method is to add locks,
1079 * needed by a given layer into cl_io.ci_lockset.
1081 * - once locks for all layers were collected, they are sorted to avoid
1082 * dead-locks (cl_io_locks_sort()), and enqueued.
1084 * - when all locks are acquired, IO is performed;
1086 * - locks are released after IO is complete.
1088 * Striping introduces major additional complexity into locking. The
1089 * fundamental problem is that it is generally unsafe to actively use (hold)
1090 * two locks on the different OST servers at the same time, as this introduces
1091 * inter-server dependency and can lead to cascading evictions.
1093 * Basic solution is to sub-divide large read/write IOs into smaller pieces so
1094 * that no multi-stripe locks are taken (note that this design abandons POSIX
1095 * read/write semantics). Such pieces ideally can be executed concurrently. At
1096 * the same time, certain types of IO cannot be sub-divived, without
1097 * sacrificing correctness. This includes:
1099 * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
1102 * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
1104 * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
1105 * buf is a part of memory mapped Lustre file, a lock or locks protecting buf
1106 * has to be held together with the usual lock on [offset, offset + count].
1108 * Interaction with DLM
1110 * In the expected setup, cl_lock is ultimately backed up by a collection of
1111 * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
1112 * implemented in osc layer, that also matches DLM events (ASTs, cancellation,
1113 * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
1114 * description of interaction with DLM.
1120 struct cl_lock_descr {
1121 /** Object this lock is granted for. */
1122 struct cl_object *cld_obj;
1123 /** Index of the first page protected by this lock. */
1125 /** Index of the last page (inclusive) protected by this lock. */
1127 /** Group ID, for group lock */
1130 enum cl_lock_mode cld_mode;
1132 * flags to enqueue lock. A combination of bit-flags from
1133 * enum cl_enq_flags.
1135 __u32 cld_enq_flags;
1138 #define DDESCR "%s(%d):[%lu, %lu]:%x"
1139 #define PDESCR(descr) \
1140 cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
1141 (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
1143 const char *cl_lock_mode_name(const enum cl_lock_mode mode);
1146 * Layered client lock.
1149 /** List of slices. Immutable after creation. */
1150 struct list_head cll_layers;
1151 /** lock attribute, extent, cl_object, etc. */
1152 struct cl_lock_descr cll_descr;
1156 * Per-layer part of cl_lock
1158 * \see lov_lock, osc_lock
1160 struct cl_lock_slice {
1161 struct cl_lock *cls_lock;
1162 /** Object slice corresponding to this lock slice. Immutable after
1164 struct cl_object *cls_obj;
1165 const struct cl_lock_operations *cls_ops;
1166 /** Linkage into cl_lock::cll_layers. Immutable after creation. */
1167 struct list_head cls_linkage;
1172 * \see lov_lock_ops, osc_lock_ops
1174 struct cl_lock_operations {
1177 * Attempts to enqueue the lock. Called top-to-bottom.
1179 * \retval 0 this layer has enqueued the lock successfully
1180 * \retval >0 this layer has enqueued the lock, but need to wait on
1181 * @anchor for resources
1182 * \retval -ve failure
1184 * \see lov_lock_enqueue(), osc_lock_enqueue()
1186 int (*clo_enqueue)(const struct lu_env *env,
1187 const struct cl_lock_slice *slice,
1188 struct cl_io *io, struct cl_sync_io *anchor);
1190 * Cancel a lock, release its DLM lock ref, while does not cancel the
1193 void (*clo_cancel)(const struct lu_env *env,
1194 const struct cl_lock_slice *slice);
1197 * Destructor. Frees resources and the slice.
1199 * \see lov_lock_fini(), osc_lock_fini()
1201 void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
1203 * Optional debugging helper. Prints given lock slice.
1205 int (*clo_print)(const struct lu_env *env,
1206 void *cookie, lu_printer_t p,
1207 const struct cl_lock_slice *slice);
1210 #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
1212 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1213 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1214 cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
1215 CDEBUG(mask, format , ## __VA_ARGS__); \
1219 #define CL_LOCK_ASSERT(expr, env, lock) do { \
1223 CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
1229 /** \addtogroup cl_page_list cl_page_list
1230 * Page list used to perform collective operations on a group of pages.
1232 * Pages are added to the list one by one. cl_page_list acquires a reference
1233 * for every page in it. Page list is used to perform collective operations on
1236 * - submit pages for an immediate transfer,
1238 * - own pages on behalf of certain io (waiting for each page in turn),
1242 * When list is finalized, it releases references on all pages it still has.
1244 * \todo XXX concurrency control.
1248 struct cl_page_list {
1250 struct list_head pl_pages;
1254 * A 2-queue of pages. A convenience data-type for common use case, 2-queue
1255 * contains an incoming page list and an outgoing page list.
1258 struct cl_page_list c2_qin;
1259 struct cl_page_list c2_qout;
1262 /** @} cl_page_list */
1264 /** \addtogroup cl_io cl_io
1269 * cl_io represents a high level I/O activity like
1270 * read(2)/write(2)/truncate(2) system call, or cancellation of an extent
1273 * cl_io is a layered object, much like cl_{object,page,lock} but with one
1274 * important distinction. We want to minimize number of calls to the allocator
1275 * in the fast path, e.g., in the case of read(2) when everything is cached:
1276 * client already owns the lock over region being read, and data are cached
1277 * due to read-ahead. To avoid allocation of cl_io layers in such situations,
1278 * per-layer io state is stored in the session, associated with the io, see
1279 * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
1280 * by using free-lists, see cl_env_get().
1282 * There is a small predefined number of possible io types, enumerated in enum
1285 * cl_io is a state machine, that can be advanced concurrently by the multiple
1286 * threads. It is up to these threads to control the concurrency and,
1287 * specifically, to detect when io is done, and its state can be safely
1290 * For read/write io overall execution plan is as following:
1292 * (0) initialize io state through all layers;
1294 * (1) loop: prepare chunk of work to do
1296 * (2) call all layers to collect locks they need to process current chunk
1298 * (3) sort all locks to avoid dead-locks, and acquire them
1300 * (4) process the chunk: call per-page methods
1301 * cl_io_operations::cio_prepare_write(),
1302 * cl_io_operations::cio_commit_write() for write)
1308 * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
1309 * address allocation efficiency issues mentioned above), and returns with the
1310 * special error condition from per-page method when current sub-io has to
1311 * block. This causes io loop to be repeated, and lov switches to the next
1312 * sub-io in its cl_io_operations::cio_iter_init() implementation.
1317 /** read system call */
1319 /** write system call */
1321 /** truncate, utime system calls */
1323 /** get data version */
1326 * page fault handling
1330 * fsync system call handling
1331 * To write out a range of file
1335 * glimpse. An io context to acquire glimpse lock.
1339 * Miscellaneous io. This is used for occasional io activity that
1340 * doesn't fit into other types. Currently this is used for:
1342 * - cancellation of an extent lock. This io exists as a context
1343 * to write dirty pages from under the lock being canceled back
1346 * - VM induced page write-out. An io context for writing page out
1347 * for memory cleansing;
1349 * - grouplock. An io context to acquire group lock.
1351 * CIT_MISC io is used simply as a context in which locks and pages
1352 * are manipulated. Such io has no internal "process", that is,
1353 * cl_io_loop() is never called for it.
1358 * To give advice about access of a file
1362 * SEEK_HOLE/SEEK_DATA handling to search holes or data
1363 * across all file objects
1370 * States of cl_io state machine
1373 /** Not initialized. */
1377 /** IO iteration started. */
1381 /** Actual IO is in progress. */
1383 /** IO for the current iteration finished. */
1385 /** Locks released. */
1387 /** Iteration completed. */
1389 /** cl_io finalized. */
1394 * IO state private for a layer.
1396 * This is usually embedded into layer session data, rather than allocated
1399 * \see vvp_io, lov_io, osc_io
1401 struct cl_io_slice {
1402 struct cl_io *cis_io;
1403 /** corresponding object slice. Immutable after creation. */
1404 struct cl_object *cis_obj;
1405 /** io operations. Immutable after creation. */
1406 const struct cl_io_operations *cis_iop;
1408 * linkage into a list of all slices for a given cl_io, hanging off
1409 * cl_io::ci_layers. Immutable after creation.
1411 struct list_head cis_linkage;
1414 typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
1417 struct cl_read_ahead {
1418 /* Maximum page index the readahead window will end.
1419 * This is determined DLM lock coverage, RPC and stripe boundary.
1420 * cra_end is included. */
1421 pgoff_t cra_end_idx;
1422 /* optimal RPC size for this read, by pages */
1423 unsigned long cra_rpc_pages;
1424 /* Release callback. If readahead holds resources underneath, this
1425 * function should be called to release it. */
1426 void (*cra_release)(const struct lu_env *env,
1427 struct cl_read_ahead *ra);
1429 /* Callback data for cra_release routine */
1433 /* whether lock is in contention */
1434 bool cra_contention;
1437 static inline void cl_read_ahead_release(const struct lu_env *env,
1438 struct cl_read_ahead *ra)
1440 if (ra->cra_release != NULL)
1441 ra->cra_release(env, ra);
1442 memset(ra, 0, sizeof(*ra));
1447 * Per-layer io operations.
1448 * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
1450 struct cl_io_operations {
1452 * Vector of io state transition methods for every io type.
1454 * \see cl_page_operations::io
1458 * Prepare io iteration at a given layer.
1460 * Called top-to-bottom at the beginning of each iteration of
1461 * "io loop" (if it makes sense for this type of io). Here
1462 * layer selects what work it will do during this iteration.
1464 * \see cl_io_operations::cio_iter_fini()
1466 int (*cio_iter_init) (const struct lu_env *env,
1467 const struct cl_io_slice *slice);
1469 * Finalize io iteration.
1471 * Called bottom-to-top at the end of each iteration of "io
1472 * loop". Here layers can decide whether IO has to be
1475 * \see cl_io_operations::cio_iter_init()
1477 void (*cio_iter_fini) (const struct lu_env *env,
1478 const struct cl_io_slice *slice);
1480 * Collect locks for the current iteration of io.
1482 * Called top-to-bottom to collect all locks necessary for
1483 * this iteration. This methods shouldn't actually enqueue
1484 * anything, instead it should post a lock through
1485 * cl_io_lock_add(). Once all locks are collected, they are
1486 * sorted and enqueued in the proper order.
1488 int (*cio_lock) (const struct lu_env *env,
1489 const struct cl_io_slice *slice);
1491 * Finalize unlocking.
1493 * Called bottom-to-top to finish layer specific unlocking
1494 * functionality, after generic code released all locks
1495 * acquired by cl_io_operations::cio_lock().
1497 void (*cio_unlock)(const struct lu_env *env,
1498 const struct cl_io_slice *slice);
1500 * Start io iteration.
1502 * Once all locks are acquired, called top-to-bottom to
1503 * commence actual IO. In the current implementation,
1504 * top-level vvp_io_{read,write}_start() does all the work
1505 * synchronously by calling generic_file_*(), so other layers
1506 * are called when everything is done.
1508 int (*cio_start)(const struct lu_env *env,
1509 const struct cl_io_slice *slice);
1511 * Called top-to-bottom at the end of io loop. Here layer
1512 * might wait for an unfinished asynchronous io.
1514 void (*cio_end) (const struct lu_env *env,
1515 const struct cl_io_slice *slice);
1517 * Called bottom-to-top to notify layers that read/write IO
1518 * iteration finished, with \a nob bytes transferred.
1520 void (*cio_advance)(const struct lu_env *env,
1521 const struct cl_io_slice *slice,
1524 * Called once per io, bottom-to-top to release io resources.
1526 void (*cio_fini) (const struct lu_env *env,
1527 const struct cl_io_slice *slice);
1531 * Submit pages from \a queue->c2_qin for IO, and move
1532 * successfully submitted pages into \a queue->c2_qout. Return
1533 * non-zero if failed to submit even the single page. If
1534 * submission failed after some pages were moved into \a
1535 * queue->c2_qout, completion callback with non-zero ioret is
1538 int (*cio_submit)(const struct lu_env *env,
1539 const struct cl_io_slice *slice,
1540 enum cl_req_type crt,
1541 struct cl_2queue *queue);
1543 * Queue async page for write.
1544 * The difference between cio_submit and cio_queue is that
1545 * cio_submit is for urgent request.
1547 int (*cio_commit_async)(const struct lu_env *env,
1548 const struct cl_io_slice *slice,
1549 struct cl_page_list *queue, int from, int to,
1552 * Release active extent.
1554 void (*cio_extent_release)(const struct lu_env *env,
1555 const struct cl_io_slice *slice);
1557 * Decide maximum read ahead extent
1559 * \pre io->ci_type == CIT_READ
1561 int (*cio_read_ahead)(const struct lu_env *env,
1562 const struct cl_io_slice *slice,
1563 pgoff_t start, struct cl_read_ahead *ra);
1566 * Reserve LRU slots before IO.
1568 int (*cio_lru_reserve) (const struct lu_env *env,
1569 const struct cl_io_slice *slice,
1570 loff_t pos, size_t bytes);
1572 * Optional debugging helper. Print given io slice.
1574 int (*cio_print)(const struct lu_env *env, void *cookie,
1575 lu_printer_t p, const struct cl_io_slice *slice);
1579 * Flags to lock enqueue procedure.
1584 * instruct server to not block, if conflicting lock is found. Instead
1585 * -EAGAIN is returned immediately.
1587 CEF_NONBLOCK = 0x00000001,
1589 * Tell lower layers this is a glimpse request, translated to
1590 * LDLM_FL_HAS_INTENT at LDLM layer.
1592 * Also, because glimpse locks never block other locks, we count this
1593 * as automatically compatible with other osc locks.
1594 * (see osc_lock_compatible)
1596 CEF_GLIMPSE = 0x00000002,
1598 * tell the server to instruct (though a flag in the blocking ast) an
1599 * owner of the conflicting lock, that it can drop dirty pages
1600 * protected by this lock, without sending them to the server.
1602 CEF_DISCARD_DATA = 0x00000004,
1604 * tell the sub layers that it must be a `real' lock. This is used for
1605 * mmapped-buffer locks, glimpse locks, manually requested locks
1606 * (LU_LADVISE_LOCKAHEAD) that must never be converted into lockless
1609 * \see vvp_mmap_locks(), cl_glimpse_lock, cl_request_lock().
1611 CEF_MUST = 0x00000008,
1613 * tell the sub layers that never request a `real' lock. This flag is
1614 * not used currently.
1616 * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
1617 * conversion policy: ci_lockreq describes generic information of lock
1618 * requirement for this IO, especially for locks which belong to the
1619 * object doing IO; however, lock itself may have precise requirements
1620 * that are described by the enqueue flags.
1622 CEF_NEVER = 0x00000010,
1624 * tell the dlm layer this is a speculative lock request
1625 * speculative lock requests are locks which are not requested as part
1626 * of an I/O operation. Instead, they are requested because we expect
1627 * to use them in the future. They are requested asynchronously at the
1630 * Currently used for asynchronous glimpse locks and manually requested
1631 * locks (LU_LADVISE_LOCKAHEAD).
1633 CEF_SPECULATIVE = 0x00000020,
1635 * enqueue a lock to test DLM lock existence.
1637 CEF_PEEK = 0x00000040,
1639 * Lock match only. Used by group lock in I/O as group lock
1640 * is known to exist.
1642 CEF_LOCK_MATCH = 0x00000080,
1644 * tell the DLM layer to lock only the requested range
1646 CEF_LOCK_NO_EXPAND = 0x00000100,
1648 * mask of enq_flags.
1650 CEF_MASK = 0x000001ff,
1654 * Link between lock and io. Intermediate structure is needed, because the
1655 * same lock can be part of multiple io's simultaneously.
1657 struct cl_io_lock_link {
1658 /** linkage into one of cl_lockset lists. */
1659 struct list_head cill_linkage;
1660 struct cl_lock cill_lock;
1661 /** optional destructor */
1662 void (*cill_fini)(const struct lu_env *env,
1663 struct cl_io_lock_link *link);
1665 #define cill_descr cill_lock.cll_descr
1668 * Lock-set represents a collection of locks, that io needs at a
1669 * time. Generally speaking, client tries to avoid holding multiple locks when
1672 * - holding extent locks over multiple ost's introduces the danger of
1673 * "cascading timeouts";
1675 * - holding multiple locks over the same ost is still dead-lock prone,
1676 * see comment in osc_lock_enqueue(),
1678 * but there are certain situations where this is unavoidable:
1680 * - O_APPEND writes have to take [0, EOF] lock for correctness;
1682 * - truncate has to take [new-size, EOF] lock for correctness;
1684 * - SNS has to take locks across full stripe for correctness;
1686 * - in the case when user level buffer, supplied to {read,write}(file0),
1687 * is a part of a memory mapped lustre file, client has to take a dlm
1688 * locks on file0, and all files that back up the buffer (or a part of
1689 * the buffer, that is being processed in the current chunk, in any
1690 * case, there are situations where at least 2 locks are necessary).
1692 * In such cases we at least try to take locks in the same consistent
1693 * order. To this end, all locks are first collected, then sorted, and then
1697 /** locks to be acquired. */
1698 struct list_head cls_todo;
1699 /** locks acquired. */
1700 struct list_head cls_done;
1704 * Lock requirements(demand) for IO. It should be cl_io_lock_req,
1705 * but 'req' is always to be thought as 'request' :-)
1707 enum cl_io_lock_dmd {
1708 /** Always lock data (e.g., O_APPEND). */
1710 /** Layers are free to decide between local and global locking. */
1712 /** Never lock: there is no cache (e.g., liblustre). */
1716 enum cl_fsync_mode {
1717 /** start writeback, do not wait for them to finish */
1719 /** start writeback and wait for them to finish */
1721 /** discard all of dirty pages in a specific file range */
1722 CL_FSYNC_DISCARD = 2,
1723 /** start writeback and make sure they have reached storage before
1724 * return. OST_SYNC RPC must be issued and finished */
1726 /** start writeback, thus the kernel can reclaim some memory */
1727 CL_FSYNC_RECLAIM = 4,
1730 struct cl_io_rw_common {
1735 enum cl_setattr_subtype {
1736 /** regular setattr **/
1740 /** fallocate(2) - mode preallocate **/
1741 CL_SETATTR_FALLOCATE
1744 struct cl_io_range {
1750 struct cl_io_pt *cip_next;
1751 struct kiocb cip_iocb;
1752 struct iov_iter cip_iter;
1753 struct file *cip_file;
1754 enum cl_io_type cip_iot;
1755 unsigned int cip_need_restart:1;
1764 * cl_io is shared by all threads participating in this IO (in current
1765 * implementation only one thread advances IO, but parallel IO design and
1766 * concurrent copy_*_user() require multiple threads acting on the same IO. It
1767 * is up to these threads to serialize their activities, including updates to
1768 * mutable cl_io fields.
1771 /** type of this IO. Immutable after creation. */
1772 enum cl_io_type ci_type;
1773 /** current state of cl_io state machine. */
1774 enum cl_io_state ci_state;
1775 /** main object this io is against. Immutable after creation. */
1776 struct cl_object *ci_obj;
1777 /** top level dio_aio */
1778 struct cl_dio_aio *ci_dio_aio;
1780 * Upper layer io, of which this io is a part of. Immutable after
1783 struct cl_io *ci_parent;
1784 /** List of slices. Immutable after creation. */
1785 struct list_head ci_layers;
1786 /** list of locks (to be) acquired by this io. */
1787 struct cl_lockset ci_lockset;
1788 /** lock requirements, this is just a help info for sublayers. */
1789 enum cl_io_lock_dmd ci_lockreq;
1790 /** layout version when this IO occurs */
1791 __u32 ci_layout_version;
1794 struct cl_io_rw_common rd;
1797 struct cl_io_rw_common wr;
1801 struct cl_io_rw_common ci_rw;
1802 struct cl_setattr_io {
1803 struct ost_lvb sa_attr;
1804 unsigned int sa_attr_flags;
1805 unsigned int sa_avalid; /* ATTR_* */
1806 unsigned int sa_xvalid; /* OP_XVALID */
1807 int sa_stripe_index;
1808 struct ost_layout sa_layout;
1809 const struct lu_fid *sa_parent_fid;
1810 /* SETATTR interface is used for regular setattr, */
1811 /* truncate(2) and fallocate(2) subtypes */
1812 enum cl_setattr_subtype sa_subtype;
1813 /* The following are used for fallocate(2) */
1815 loff_t sa_falloc_offset;
1816 loff_t sa_falloc_end;
1817 uid_t sa_falloc_uid;
1818 gid_t sa_falloc_gid;
1819 __u32 sa_falloc_projid;
1821 struct cl_data_version_io {
1822 u64 dv_data_version;
1823 u32 dv_layout_version;
1826 struct cl_fault_io {
1827 /** page index within file. */
1829 /** bytes valid byte on a faulted page. */
1831 /** writable page? for nopage() only */
1833 /** page of an executable? */
1835 /** page_mkwrite() */
1837 /** resulting page */
1838 struct cl_page *ft_page;
1840 struct cl_fsync_io {
1843 /** file system level fid */
1844 struct lu_fid *fi_fid;
1845 enum cl_fsync_mode fi_mode;
1846 /* how many pages were written/discarded */
1847 unsigned int fi_nr_written;
1849 struct cl_ladvise_io {
1852 /** file system level fid */
1853 struct lu_fid *li_fid;
1854 enum lu_ladvise_type li_advice;
1857 struct cl_lseek_io {
1863 time64_t lm_next_rpc_time;
1866 struct cl_2queue ci_queue;
1869 unsigned int ci_continue:1,
1871 * This io has held grouplock, to inform sublayers that
1872 * don't do lockless i/o.
1876 * The whole IO need to be restarted because layout has been changed
1880 * to not refresh layout - the IO issuer knows that the layout won't
1881 * change(page operations, layout change causes all page to be
1882 * discarded), or it doesn't matter if it changes(sync).
1886 * Need MDS intervention to complete a write.
1887 * Write intent is required for the following cases:
1888 * 1. component being written is not initialized, or
1889 * 2. the mirrored files are NOT in WRITE_PENDING state.
1891 ci_need_write_intent:1,
1893 * Check if layout changed after the IO finishes. Mainly for HSM
1894 * requirement. If IO occurs to openning files, it doesn't need to
1895 * verify layout because HSM won't release openning files.
1896 * Right now, only two opertaions need to verify layout: glimpse
1901 * file is released, restore has to to be triggered by vvp layer
1903 ci_restore_needed:1,
1908 /* Tell sublayers not to expand LDLM locks requested for this IO */
1909 ci_lock_no_expand:1,
1911 * Set if non-delay RPC should be used for this IO.
1913 * If this file has multiple mirrors, and if the OSTs of the current
1914 * mirror is inaccessible, non-delay RPC would error out quickly so
1915 * that the upper layer can try to access the next mirror.
1919 * Set if IO is triggered by async workqueue readahead.
1921 ci_async_readahead:1,
1923 * Ignore lockless and do normal locking for this io.
1927 * Set if we've tried all mirrors for this read IO, if it's not set,
1928 * the read IO will check to-be-read OSCs' status, and make fast-switch
1929 * another mirror if some of the OSTs are not healthy.
1931 ci_tried_all_mirrors:1,
1933 * Random read hints, readahead will be disabled.
1937 * Sequential read hints.
1941 * Do parallel (async) submission of DIO RPCs. Note DIO is still sync
1942 * to userspace, only the RPCs are submitted async, then waited for at
1943 * the llite layer before returning.
1947 * Bypass quota check
1949 unsigned ci_noquota:1,
1951 * io_uring direct IO with flags IOCB_NOWAIT.
1955 * The filesystem must exclusively acquire invalidate_lock before
1956 * invalidating page cache in truncate / hole punch / DLM extent
1957 * lock blocking AST path (and thus calling into ->invalidatepage)
1958 * to block races between page cache invalidation and page cache
1959 * filling functions (fault, read, ...)
1961 ci_invalidate_page_cache:1;
1964 * How many times the read has retried before this one.
1965 * Set by the top level and consumed by the LOV.
1967 unsigned ci_ndelay_tried;
1969 * Designated mirror index for this I/O.
1971 unsigned ci_designated_mirror;
1973 * Number of pages owned by this IO. For invariant checking.
1975 unsigned ci_owned_nr;
1977 * Range of write intent. Valid if ci_need_write_intent is set.
1979 struct lu_extent ci_write_intent;
1985 * Per-transfer attributes.
1987 struct cl_req_attr {
1988 enum cl_req_type cra_type;
1990 struct cl_page *cra_page;
1991 /** Generic attributes for the server consumption. */
1992 struct obdo *cra_oa;
1994 char cra_jobid[LUSTRE_JOBID_SIZE];
1995 /** uid/gid of the process doing an io */
2000 enum cache_stats_item {
2001 /** how many cache lookups were performed */
2003 /** how many times cache lookup resulted in a hit */
2005 /** how many entities are in the cache right now */
2007 /** how many entities in the cache are actively used (and cannot be
2008 * evicted) right now */
2010 /** how many entities were created at all */
2015 #define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
2018 * Stats for a generic cache (similar to inode, lu_object, etc. caches).
2020 struct cache_stats {
2021 const char *cs_name;
2022 atomic_t cs_stats[CS_NR];
2025 /** These are not exported so far */
2026 void cache_stats_init (struct cache_stats *cs, const char *name);
2029 * Client-side site. This represents particular client stack. "Global"
2030 * variables should (directly or indirectly) be added here to allow multiple
2031 * clients to co-exist in the single address space.
2034 struct lu_site cs_lu;
2036 * Statistical counters. Atomics do not scale, something better like
2037 * per-cpu counters is needed.
2039 * These are exported as /proc/fs/lustre/llite/.../site
2041 * When interpreting keep in mind that both sub-locks (and sub-pages)
2042 * and top-locks (and top-pages) are accounted here.
2044 struct cache_stats cs_pages;
2045 atomic_t cs_pages_state[CPS_NR];
2048 int cl_site_init(struct cl_site *s, struct cl_device *top);
2049 void cl_site_fini(struct cl_site *s);
2050 void cl_stack_fini(const struct lu_env *env, struct cl_device *cl);
2053 * Output client site statistical counters into a buffer. Suitable for
2054 * ll_rd_*()-style functions.
2056 int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
2061 * Type conversion and accessory functions.
2065 static inline struct cl_site *lu2cl_site(const struct lu_site *site)
2067 return container_of(site, struct cl_site, cs_lu);
2070 static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
2072 LASSERT(d == NULL || IS_ERR(d) || lu_device_is_cl(d));
2073 return container_of_safe(d, struct cl_device, cd_lu_dev);
2076 static inline struct lu_device *cl2lu_dev(struct cl_device *d)
2078 return &d->cd_lu_dev;
2081 static inline struct cl_object *lu2cl(const struct lu_object *o)
2083 LASSERT(o == NULL || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
2084 return container_of_safe(o, struct cl_object, co_lu);
2087 static inline const struct cl_object_conf *
2088 lu2cl_conf(const struct lu_object_conf *conf)
2090 return container_of_safe(conf, struct cl_object_conf, coc_lu);
2093 static inline struct cl_object *cl_object_next(const struct cl_object *obj)
2095 return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL;
2098 static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
2100 return container_of_safe(h, struct cl_object_header, coh_lu);
2103 static inline struct cl_site *cl_object_site(const struct cl_object *obj)
2105 return lu2cl_site(obj->co_lu.lo_dev->ld_site);
2109 struct cl_object_header *cl_object_header(const struct cl_object *obj)
2111 return luh2coh(obj->co_lu.lo_header);
2114 static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
2116 return lu_device_init(&d->cd_lu_dev, t);
2119 static inline void cl_device_fini(struct cl_device *d)
2121 lu_device_fini(&d->cd_lu_dev);
2124 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
2125 struct cl_object *obj,
2126 const struct cl_page_operations *ops);
2127 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
2128 struct cl_object *obj,
2129 const struct cl_lock_operations *ops);
2130 void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
2131 struct cl_object *obj, const struct cl_io_operations *ops);
2134 /** \defgroup cl_object cl_object
2136 struct cl_object *cl_object_top (struct cl_object *o);
2137 struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
2138 const struct lu_fid *fid,
2139 const struct cl_object_conf *c);
2141 int cl_object_header_init(struct cl_object_header *h);
2142 void cl_object_header_fini(struct cl_object_header *h);
2143 void cl_object_put (const struct lu_env *env, struct cl_object *o);
2144 void cl_object_get (struct cl_object *o);
2145 void cl_object_attr_lock (struct cl_object *o);
2146 void cl_object_attr_unlock(struct cl_object *o);
2147 int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
2148 struct cl_attr *attr);
2149 int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
2150 const struct cl_attr *attr, unsigned valid);
2151 void cl_object_dirty_for_sync(const struct lu_env *env, struct cl_object *obj);
2152 int cl_object_glimpse (const struct lu_env *env, struct cl_object *obj,
2153 struct ost_lvb *lvb);
2154 int cl_conf_set (const struct lu_env *env, struct cl_object *obj,
2155 const struct cl_object_conf *conf);
2156 int cl_object_prune (const struct lu_env *env, struct cl_object *obj);
2157 void cl_object_kill (const struct lu_env *env, struct cl_object *obj);
2158 int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj,
2159 struct lov_user_md __user *lum, size_t size);
2160 int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj,
2161 struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap,
2163 int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj,
2164 struct cl_layout *cl);
2165 loff_t cl_object_maxbytes(struct cl_object *obj);
2166 int cl_object_flush(const struct lu_env *env, struct cl_object *obj,
2167 struct ldlm_lock *lock);
2168 int cl_object_inode_ops(const struct lu_env *env, struct cl_object *obj,
2169 enum coo_inode_opc opc, void *data);
2173 * Returns true, iff \a o0 and \a o1 are slices of the same object.
2175 static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
2177 return cl_object_header(o0) == cl_object_header(o1);
2180 static inline void cl_object_page_init(struct cl_object *clob, int size)
2182 clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
2183 cl_object_header(clob)->coh_page_bufsize += round_up(size, 8);
2184 WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
2187 static inline void *cl_object_page_slice(struct cl_object *clob,
2188 struct cl_page *page)
2190 return (void *)((char *)page + clob->co_slice_off);
2194 * Return refcount of cl_object.
2196 static inline int cl_object_refc(struct cl_object *clob)
2198 struct lu_object_header *header = clob->co_lu.lo_header;
2199 return atomic_read(&header->loh_ref);
2204 /** \defgroup cl_page cl_page
2206 struct cl_page *cl_page_find (const struct lu_env *env,
2207 struct cl_object *obj,
2208 pgoff_t idx, struct page *vmpage,
2209 enum cl_page_type type);
2210 struct cl_page *cl_page_alloc (const struct lu_env *env,
2211 struct cl_object *o, pgoff_t ind,
2212 struct page *vmpage,
2213 enum cl_page_type type);
2214 void cl_page_get (struct cl_page *page);
2215 void cl_page_put (const struct lu_env *env,
2216 struct cl_page *page);
2217 void cl_pagevec_put (const struct lu_env *env,
2218 struct cl_page *page,
2219 struct pagevec *pvec);
2220 void cl_page_print (const struct lu_env *env, void *cookie,
2221 lu_printer_t printer,
2222 const struct cl_page *pg);
2223 void cl_page_header_print(const struct lu_env *env, void *cookie,
2224 lu_printer_t printer,
2225 const struct cl_page *pg);
2226 struct cl_page *cl_vmpage_page (struct page *vmpage, struct cl_object *obj);
2231 * Functions dealing with the ownership of page by io.
2235 int cl_page_own (const struct lu_env *env,
2236 struct cl_io *io, struct cl_page *page);
2237 int cl_page_own_try (const struct lu_env *env,
2238 struct cl_io *io, struct cl_page *page);
2239 void cl_page_assume (const struct lu_env *env,
2240 struct cl_io *io, struct cl_page *page);
2241 void cl_page_unassume (const struct lu_env *env,
2242 struct cl_io *io, struct cl_page *pg);
2243 void cl_page_disown (const struct lu_env *env,
2244 struct cl_io *io, struct cl_page *page);
2245 int cl_page_is_owned (const struct cl_page *pg, const struct cl_io *io);
2252 * Functions dealing with the preparation of a page for a transfer, and
2253 * tracking transfer state.
2256 int cl_page_prep (const struct lu_env *env, struct cl_io *io,
2257 struct cl_page *pg, enum cl_req_type crt);
2258 void cl_page_completion (const struct lu_env *env,
2259 struct cl_page *pg, enum cl_req_type crt, int ioret);
2260 int cl_page_make_ready (const struct lu_env *env, struct cl_page *pg,
2261 enum cl_req_type crt);
2262 int cl_page_cache_add (const struct lu_env *env, struct cl_io *io,
2263 struct cl_page *pg, enum cl_req_type crt);
2264 void cl_page_clip (const struct lu_env *env, struct cl_page *pg,
2266 int cl_page_flush (const struct lu_env *env, struct cl_io *io,
2267 struct cl_page *pg);
2273 * \name helper routines
2274 * Functions to discard, delete and export a cl_page.
2277 void cl_page_discard(const struct lu_env *env, struct cl_io *io,
2278 struct cl_page *pg);
2279 void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
2280 void cl_page_touch(const struct lu_env *env, const struct cl_page *pg,
2283 void cl_lock_print(const struct lu_env *env, void *cookie,
2284 lu_printer_t printer, const struct cl_lock *lock);
2285 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2286 lu_printer_t printer,
2287 const struct cl_lock_descr *descr);
2291 * Data structure managing a client's cached pages. A count of
2292 * "unstable" pages is maintained, and an LRU of clean pages is
2293 * maintained. "unstable" pages are pages pinned by the ptlrpc
2294 * layer for recovery purposes.
2296 struct cl_client_cache {
2298 * # of client cache refcount
2299 * # of users (OSCs) + 2 (held by llite and lov)
2301 refcount_t ccc_users;
2303 * # of threads are doing shrinking
2305 unsigned int ccc_lru_shrinkers;
2307 * # of LRU entries available
2309 atomic_long_t ccc_lru_left;
2311 * List of entities(OSCs) for this LRU cache
2313 struct list_head ccc_lru;
2315 * Max # of LRU entries
2317 unsigned long ccc_lru_max;
2319 * Lock to protect ccc_lru list
2321 spinlock_t ccc_lru_lock;
2323 * Set if unstable check is enabled
2325 unsigned int ccc_unstable_check:1;
2327 * # of unstable pages for this mount point
2329 atomic_long_t ccc_unstable_nr;
2331 * Waitq for awaiting unstable pages to reach zero.
2332 * Used at umounting time and signaled on BRW commit
2334 wait_queue_head_t ccc_unstable_waitq;
2336 * Serialize max_cache_mb write operation
2338 struct mutex ccc_max_cache_mb_lock;
2341 * cl_cache functions
2343 struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
2344 void cl_cache_incref(struct cl_client_cache *cache);
2345 void cl_cache_decref(struct cl_client_cache *cache);
2349 /** \defgroup cl_lock cl_lock
2351 int cl_lock_request(const struct lu_env *env, struct cl_io *io,
2352 struct cl_lock *lock);
2353 int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
2354 const struct cl_io *io);
2355 void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
2356 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
2357 const struct lu_device_type *dtype);
2358 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
2360 int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
2361 struct cl_lock *lock, struct cl_sync_io *anchor);
2362 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
2366 /** \defgroup cl_io cl_io
2369 int cl_io_init(const struct lu_env *env, struct cl_io *io,
2370 enum cl_io_type iot, struct cl_object *obj);
2371 int cl_io_sub_init(const struct lu_env *env, struct cl_io *io,
2372 enum cl_io_type iot, struct cl_object *obj);
2373 int cl_io_rw_init(const struct lu_env *env, struct cl_io *io,
2374 enum cl_io_type iot, loff_t pos, size_t bytes);
2375 int cl_io_loop(const struct lu_env *env, struct cl_io *io);
2377 void cl_io_fini(const struct lu_env *env, struct cl_io *io);
2378 int cl_io_iter_init(const struct lu_env *env, struct cl_io *io);
2379 void cl_io_iter_fini(const struct lu_env *env, struct cl_io *io);
2380 int cl_io_lock(const struct lu_env *env, struct cl_io *io);
2381 void cl_io_unlock(const struct lu_env *env, struct cl_io *io);
2382 int cl_io_start(const struct lu_env *env, struct cl_io *io);
2383 void cl_io_end(const struct lu_env *env, struct cl_io *io);
2384 int cl_io_lock_add(const struct lu_env *env, struct cl_io *io,
2385 struct cl_io_lock_link *link);
2386 int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
2387 struct cl_lock_descr *descr);
2388 int cl_io_submit_rw (const struct lu_env *env, struct cl_io *io,
2389 enum cl_req_type iot, struct cl_2queue *queue);
2390 int cl_io_submit_sync (const struct lu_env *env, struct cl_io *io,
2391 enum cl_req_type iot, struct cl_2queue *queue,
2393 int cl_io_commit_async (const struct lu_env *env, struct cl_io *io,
2394 struct cl_page_list *queue, int from, int to,
2396 void cl_io_extent_release (const struct lu_env *env, struct cl_io *io);
2397 int cl_io_lru_reserve(const struct lu_env *env, struct cl_io *io,
2398 loff_t pos, size_t bytes);
2399 int cl_io_read_ahead (const struct lu_env *env, struct cl_io *io,
2400 pgoff_t start, struct cl_read_ahead *ra);
2401 void cl_io_rw_advance(const struct lu_env *env, struct cl_io *io,
2405 * True, iff \a io is an O_APPEND write(2).
2407 static inline int cl_io_is_append(const struct cl_io *io)
2409 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
2412 static inline int cl_io_is_sync_write(const struct cl_io *io)
2414 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
2417 static inline int cl_io_is_mkwrite(const struct cl_io *io)
2419 return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
2423 * True, iff \a io is a truncate(2).
2425 static inline int cl_io_is_trunc(const struct cl_io *io)
2427 return io->ci_type == CIT_SETATTR &&
2428 (io->u.ci_setattr.sa_avalid & ATTR_SIZE) &&
2429 (io->u.ci_setattr.sa_subtype != CL_SETATTR_FALLOCATE);
2432 static inline int cl_io_is_fallocate(const struct cl_io *io)
2434 return (io->ci_type == CIT_SETATTR) &&
2435 (io->u.ci_setattr.sa_subtype == CL_SETATTR_FALLOCATE);
2438 struct cl_io *cl_io_top(struct cl_io *io);
2440 #define CL_IO_SLICE_CLEAN(obj, base) memset_startat(obj, 0, base)
2444 /** \defgroup cl_page_list cl_page_list
2448 * Last page in the page list.
2450 static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
2452 LASSERT(plist->pl_nr > 0);
2453 return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
2456 static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
2458 LASSERT(plist->pl_nr > 0);
2459 return list_first_entry(&plist->pl_pages, struct cl_page, cp_batch);
2463 * Iterate over pages in a page list.
2465 #define cl_page_list_for_each(page, list) \
2466 list_for_each_entry((page), &(list)->pl_pages, cp_batch)
2469 * Iterate over pages in a page list, taking possible removals into account.
2471 #define cl_page_list_for_each_safe(page, temp, list) \
2472 list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
2474 void cl_page_list_init(struct cl_page_list *plist);
2475 void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page,
2477 void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src,
2478 struct cl_page *page);
2479 void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
2480 struct cl_page *page);
2481 void cl_page_list_splice(struct cl_page_list *list,
2482 struct cl_page_list *head);
2483 void cl_page_list_del(const struct lu_env *env,
2484 struct cl_page_list *plist, struct cl_page *page);
2485 void cl_page_list_disown(const struct lu_env *env,
2486 struct cl_page_list *plist);
2487 void cl_page_list_assume(const struct lu_env *env,
2488 struct cl_io *io, struct cl_page_list *plist);
2489 void cl_page_list_discard(const struct lu_env *env,
2490 struct cl_io *io, struct cl_page_list *plist);
2491 void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist);
2493 void cl_2queue_init(struct cl_2queue *queue);
2494 void cl_2queue_disown(const struct lu_env *env, struct cl_2queue *queue);
2495 void cl_2queue_assume(const struct lu_env *env, struct cl_io *io,
2496 struct cl_2queue *queue);
2497 void cl_2queue_discard(const struct lu_env *env, struct cl_io *io,
2498 struct cl_2queue *queue);
2499 void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue);
2500 void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
2502 /** @} cl_page_list */
2504 void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
2505 struct cl_req_attr *attr);
2507 /** \defgroup cl_sync_io cl_sync_io
2514 typedef void (cl_sync_io_end_t)(const struct lu_env *, struct cl_sync_io *);
2516 void cl_sync_io_init_notify(struct cl_sync_io *anchor, int nr, void *dio_aio,
2517 cl_sync_io_end_t *end);
2519 int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
2521 void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
2523 int cl_sync_io_wait_recycle(const struct lu_env *env, struct cl_sync_io *anchor,
2524 long timeout, int ioret);
2525 struct cl_dio_aio *cl_dio_aio_alloc(struct kiocb *iocb, struct cl_object *obj,
2527 struct cl_sub_dio *cl_sub_dio_alloc(struct cl_dio_aio *ll_aio,
2528 struct iov_iter *iter, bool write,
2530 void cl_dio_aio_free(const struct lu_env *env, struct cl_dio_aio *aio);
2531 void cl_sub_dio_free(struct cl_sub_dio *sdio);
2532 static inline void cl_sync_io_init(struct cl_sync_io *anchor, int nr)
2534 cl_sync_io_init_notify(anchor, nr, NULL, NULL);
2538 * Anchor for synchronous transfer. This is allocated on a stack by thread
2539 * doing synchronous transfer, and a pointer to this structure is set up in
2540 * every page submitted for transfer. Transfer completion routine updates
2541 * anchor and wakes up waiting thread when transfer is complete.
2544 /** number of pages yet to be transferred. */
2545 atomic_t csi_sync_nr;
2546 /** has this i/o completed? */
2547 atomic_t csi_complete;
2550 /** completion to be signaled when transfer is complete. */
2551 wait_queue_head_t csi_waitq;
2552 /** callback to invoke when this IO is finished */
2553 cl_sync_io_end_t *csi_end_io;
2554 /* private pointer for an associated DIO/AIO */
2558 /** direct IO pages */
2559 struct ll_dio_pages {
2561 * page array to be written. we don't support
2562 * partial pages except the last one.
2564 struct page **ldp_pages;
2565 /** # of pages in the array. */
2567 /* the file offset of the first page. */
2568 loff_t ldp_file_offset;
2571 /* Top level struct used for AIO and DIO */
2573 struct cl_sync_io cda_sync;
2574 struct cl_object *cda_obj;
2575 struct kiocb *cda_iocb;
2577 struct mm_struct *cda_mm;
2578 unsigned cda_no_aio_complete:1,
2582 /* Sub-dio used for splitting DIO (and AIO, because AIO is DIO) according to
2583 * the layout/striping, so we can do parallel submit of DIO RPCs
2586 struct cl_sync_io csd_sync;
2587 struct cl_page_list csd_pages;
2589 struct cl_dio_aio *csd_ll_aio;
2590 struct ll_dio_pages csd_dio_pages;
2591 struct iov_iter csd_iter;
2592 unsigned csd_creator_free:1,
2595 #if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW) || \
2596 defined(HAVE_DIRECTIO_2ARGS)
2597 #define HAVE_DIO_ITER 1
2600 void ll_release_user_pages(struct page **pages, int npages);
2602 #ifndef HAVE_KTHREAD_USE_MM
2603 #define kthread_use_mm(mm) use_mm(mm)
2604 #define kthread_unuse_mm(mm) unuse_mm(mm)
2607 /** @} cl_sync_io */
2609 /** \defgroup cl_env cl_env
2611 * lu_env handling for a client.
2613 * lu_env is an environment within which lustre code executes. Its major part
2614 * is lu_context---a fast memory allocation mechanism that is used to conserve
2615 * precious kernel stack space. Originally lu_env was designed for a server,
2618 * - there is a (mostly) fixed number of threads, and
2620 * - call chains have no non-lustre portions inserted between lustre code.
2622 * On a client both these assumtpion fails, because every user thread can
2623 * potentially execute lustre code as part of a system call, and lustre calls
2624 * into VFS or MM that call back into lustre.
2626 * To deal with that, cl_env wrapper functions implement the following
2629 * - allocation and destruction of environment is amortized by caching no
2630 * longer used environments instead of destroying them;
2632 * \see lu_env, lu_context, lu_context_key
2635 struct lu_env *cl_env_get(__u16 *refcheck);
2636 struct lu_env *cl_env_alloc(__u16 *refcheck, __u32 tags);
2637 void cl_env_put(struct lu_env *env, __u16 *refcheck);
2638 unsigned cl_env_cache_purge(unsigned nr);
2639 struct lu_env *cl_env_percpu_get(void);
2640 void cl_env_percpu_put(struct lu_env *env);
2647 void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr);
2648 void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
2650 struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
2651 struct lu_device_type *ldt,
2652 struct lu_device *next);
2655 int cl_global_init(void);
2656 void cl_global_fini(void);
2658 #endif /* _LINUX_CL_OBJECT_H */