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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
87 * super-class definitions.
89 #include <linux/aio.h>
92 #include <libcfs/libcfs.h>
93 #include <lu_object.h>
94 #include <linux/atomic.h>
95 #include <linux/mutex.h>
96 #include <linux/radix-tree.h>
97 #include <linux/spinlock.h>
98 #include <linux/wait.h>
99 #include <linux/pagevec.h>
100 #include <libcfs/linux/linux-misc.h>
101 #include <lustre_dlm.h>
102 #include <lustre_compat.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;
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 unsigned int cat_kms_valid:1;
146 * Known minimal size, in bytes.
148 * This is only valid when at least one DLM lock is held.
151 /** Modification time. Measured in seconds since epoch. */
153 /** Access time. Measured in seconds since epoch. */
155 /** Change time. Measured in seconds since epoch. */
158 * Blocks allocated to this cl_object on the server file system.
160 * \todo XXX An interface for block size is needed.
164 * User identifier for quota purposes.
168 * Group identifier for quota purposes.
172 /* nlink of the directory */
175 /* Project identifier for quota purpose. */
180 * Fields in cl_attr that are being set.
195 * Sub-class of lu_object with methods common for objects on the client
198 * cl_object: represents a regular file system object, both a file and a
199 * stripe. cl_object is based on lu_object: it is identified by a fid,
200 * layered, cached, hashed, and lrued. Important distinction with the server
201 * side, where md_object and dt_object are used, is that cl_object "fans out"
202 * at the lov/sns level: depending on the file layout, single file is
203 * represented as a set of "sub-objects" (stripes). At the implementation
204 * level, struct lov_object contains an array of cl_objects. Each sub-object
205 * is a full-fledged cl_object, having its fid, living in the lru and hash
208 * This leads to the next important difference with the server side: on the
209 * client, it's quite usual to have objects with the different sequence of
210 * layers. For example, typical top-object is composed of the following
216 * whereas its sub-objects are composed of
221 * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep
222 * track of the object-subobject relationship.
224 * Sub-objects are not cached independently: when top-object is about to
225 * be discarded from the memory, all its sub-objects are torn-down and
228 * \see vvp_object, lov_object, lovsub_object, osc_object
232 struct lu_object co_lu;
233 /** per-object-layer operations */
234 const struct cl_object_operations *co_ops;
235 /** offset of page slice in cl_page buffer */
240 * Description of the client object configuration. This is used for the
241 * creation of a new client object that is identified by a more state than
244 struct cl_object_conf {
246 struct lu_object_conf coc_lu;
249 * Object layout. This is consumed by lov.
251 struct lu_buf coc_layout;
253 * Description of particular stripe location in the
254 * cluster. This is consumed by osc.
256 struct lov_oinfo *coc_oinfo;
259 * VFS inode. This is consumed by vvp.
261 struct inode *coc_inode;
263 * Layout lock handle.
265 struct ldlm_lock *coc_lock;
268 * Operation to handle layout, OBJECT_CONF_XYZ.
274 /** configure layout, new stripe, must must be holding layout lock. */
276 /** invalidate the current stripe config when losing layout lock. */
277 OBJECT_CONF_INVALIDATE = 1,
278 /** wait for old layout to go away so that new layout can be set up. */
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 */
298 /** Whether layout is a readonly one */
310 * Operations implemented for each cl object layer.
312 * \see vvp_ops, lov_ops, lovsub_ops, osc_ops
314 struct cl_object_operations {
316 * Initialize page slice for this layer. Called top-to-bottom through
317 * every object layer when a new cl_page is instantiated. Layer
318 * keeping private per-page data, or requiring its own page operations
319 * vector should allocate these data here, and attach then to the page
320 * by calling cl_page_slice_add(). \a vmpage is locked (in the VM
323 * \retval NULL success.
325 * \retval ERR_PTR(errno) failure code.
327 * \retval valid-pointer pointer to already existing referenced page
328 * to be used instead of newly created.
330 int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj,
331 struct cl_page *page, pgoff_t index);
333 * Initialize lock slice for this layer. Called top-to-bottom through
334 * every object layer when a new cl_lock is instantiated. Layer
335 * keeping private per-lock data, or requiring its own lock operations
336 * vector should allocate these data here, and attach then to the lock
337 * by calling cl_lock_slice_add(). Mandatory.
339 int (*coo_lock_init)(const struct lu_env *env,
340 struct cl_object *obj, struct cl_lock *lock,
341 const struct cl_io *io);
343 * Initialize io state for a given layer.
345 * called top-to-bottom once per io existence to initialize io
346 * state. If layer wants to keep some state for this type of io, it
347 * has to embed struct cl_io_slice in lu_env::le_ses, and register
348 * slice with cl_io_slice_add(). It is guaranteed that all threads
349 * participating in this io share the same session.
351 int (*coo_io_init)(const struct lu_env *env,
352 struct cl_object *obj, struct cl_io *io);
354 * Fill portion of \a attr that this layer controls. This method is
355 * called top-to-bottom through all object layers.
357 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
359 * \return 0: to continue
360 * \return +ve: to stop iterating through layers (but 0 is returned
361 * from enclosing cl_object_attr_get())
362 * \return -ve: to signal error
364 int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj,
365 struct cl_attr *attr);
369 * \a valid is a bitmask composed from enum #cl_attr_valid, and
370 * indicating what attributes are to be set.
372 * \pre cl_object_header::coh_attr_guard of the top-object is locked.
374 * \return the same convention as for
375 * cl_object_operations::coo_attr_get() is used.
377 int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj,
378 const struct cl_attr *attr, unsigned int valid);
380 * Mark the inode dirty. By this way, the inode will add into the
381 * writeback list of the corresponding @bdi_writeback, and then it will
382 * defer to write out the dirty pages to OSTs via the kernel writeback
385 void (*coo_dirty_for_sync)(const struct lu_env *env,
386 struct cl_object *obj);
388 * Update object configuration. Called top-to-bottom to modify object
391 * XXX error conditions and handling.
393 int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj,
394 const struct cl_object_conf *conf);
396 * Glimpse ast. Executed when glimpse ast arrives for a lock on this
397 * object. Layers are supposed to fill parts of \a lvb that will be
398 * shipped to the glimpse originator as a glimpse result.
400 * \see vvp_object_glimpse(), lovsub_object_glimpse(),
401 * \see osc_object_glimpse()
403 int (*coo_glimpse)(const struct lu_env *env,
404 const struct cl_object *obj, struct ost_lvb *lvb);
406 * Object prune method. Called when the layout is going to change on
407 * this object, therefore each layer has to clean up their cache,
408 * mainly pages and locks.
410 int (*coo_prune)(const struct lu_env *env, struct cl_object *obj);
412 * Object getstripe method.
414 int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj,
415 struct lov_user_md __user *lum, size_t size);
417 * Get FIEMAP mapping from the object.
419 int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj,
420 struct ll_fiemap_info_key *fmkey,
421 struct fiemap *fiemap, size_t *buflen);
423 * Get layout and generation of the object.
425 int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj,
426 struct cl_layout *layout);
428 * Get maximum size of the object.
430 loff_t (*coo_maxbytes)(struct cl_object *obj);
432 * Set request attributes.
434 void (*coo_req_attr_set)(const struct lu_env *env,
435 struct cl_object *obj,
436 struct cl_req_attr *attr);
438 * Flush \a obj data corresponding to \a lock. Used for DoM
439 * locks in llite's cancelling blocking ast callback.
441 int (*coo_object_flush)(const struct lu_env *env,
442 struct cl_object *obj,
443 struct ldlm_lock *lock);
445 * operate upon inode. Used in LOV to lock/unlock inode from vvp layer.
447 int (*coo_inode_ops)(const struct lu_env *env, struct cl_object *obj,
448 enum coo_inode_opc opc, void *data);
452 * Extended header for client object.
454 struct cl_object_header {
455 /* Standard lu_object_header. cl_object::co_lu::lo_header points here.*/
456 struct lu_object_header coh_lu;
459 * Parent object. It is assumed that an object has a well-defined
460 * parent, but not a well-defined child (there may be multiple
461 * sub-objects, for the same top-object). cl_object_header::coh_parent
462 * field allows certain code to be written generically, without
463 * limiting possible cl_object layouts unduly.
465 struct cl_object_header *coh_parent;
467 * Protects consistency between cl_attr of parent object and
468 * attributes of sub-objects, that the former is calculated ("merged")
471 * \todo XXX this can be read/write lock if needed.
473 spinlock_t coh_attr_guard;
475 * Size of cl_page + page slices
477 unsigned short coh_page_bufsize;
479 * Number of objects above this one: 0 for a top-object, 1 for its
482 unsigned char coh_nesting;
486 * Helper macro: iterate over all layers of the object \a obj, assigning every
487 * layer top-to-bottom to \a slice.
489 #define cl_object_for_each(slice, obj) \
490 list_for_each_entry((slice), \
491 &(obj)->co_lu.lo_header->loh_layers,\
495 * Helper macro: iterate over all layers of the object \a obj, assigning every
496 * layer bottom-to-top to \a slice.
498 #define cl_object_for_each_reverse(slice, obj) \
499 list_for_each_entry_reverse((slice), \
500 &(obj)->co_lu.lo_header->loh_layers,\
503 #define CL_PAGE_EOF ((pgoff_t)~0ull)
506 * Layered client page.
508 * cl_page: represents a portion of a file, cached in the memory. All pages
509 * of the given file are of the same size, and are kept in the radix tree
510 * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects
511 * of the top-level file object are first class cl_objects, they have their
512 * own radix trees of pages and hence page is implemented as a sequence of
513 * struct cl_pages's, linked into double-linked list through
514 * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the
515 * corresponding radix tree at the corresponding logical offset.
517 * cl_page is associated with VM page of the hosting environment (struct
518 * page in Linux kernel, for example), struct page. It is assumed, that this
519 * association is implemented by one of cl_page layers (top layer in the
520 * current design) that
522 * - intercepts per-VM-page call-backs made by the environment (e.g.,
525 * - translates state (page flag bits) and locking between lustre and
528 * The association between cl_page and struct page is immutable and
529 * established when cl_page is created.
531 * cl_page can be "owned" by a particular cl_io (see below), guaranteeing
532 * this io an exclusive access to this page w.r.t. other io attempts and
533 * various events changing page state (such as transfer completion, or
534 * eviction of the page from the memory). Note, that in general cl_io
535 * cannot be identified with a particular thread, and page ownership is not
536 * exactly equal to the current thread holding a lock on the page. Layer
537 * implementing association between cl_page and struct page has to implement
538 * ownership on top of available synchronization mechanisms.
540 * While lustre client maintains the notion of an page ownership by io,
541 * hosting MM/VM usually has its own page concurrency control
542 * mechanisms. For example, in Linux, page access is synchronized by the
543 * per-page PG_locked bit-lock, and generic kernel code (generic_file_*())
544 * takes care to acquire and release such locks as necessary around the
545 * calls to the file system methods (->readpage(), ->prepare_write(),
546 * ->commit_write(), etc.). This leads to the situation when there are two
547 * different ways to own a page in the client:
549 * - client code explicitly and voluntary owns the page (cl_page_own());
551 * - VM locks a page and then calls the client, that has "to assume"
552 * the ownership from the VM (cl_page_assume()).
554 * Dual methods to release ownership are cl_page_disown() and
555 * cl_page_unassume().
557 * cl_page is reference counted (cl_page::cp_ref). When reference counter
558 * drops to 0, the page is returned to the cache, unless it is in
559 * cl_page_state::CPS_FREEING state, in which case it is immediately
562 * The general logic guaranteeing the absence of "existential races" for
563 * pages is the following:
565 * - there are fixed known ways for a thread to obtain a new reference
568 * - by doing a lookup in the cl_object radix tree, protected by the
571 * - by starting from VM-locked struct page and following some
572 * hosting environment method (e.g., following ->private pointer in
573 * the case of Linux kernel), see cl_vmpage_page();
575 * - when the page enters cl_page_state::CPS_FREEING state, all these
576 * ways are severed with the proper synchronization
577 * (cl_page_delete());
579 * - entry into cl_page_state::CPS_FREEING is serialized by the VM page
582 * - no new references to the page in cl_page_state::CPS_FREEING state
583 * are allowed (checked in cl_page_get()).
585 * Together this guarantees that when last reference to a
586 * cl_page_state::CPS_FREEING page is released, it is safe to destroy the
587 * page, as neither references to it can be acquired at that point, nor
590 * cl_page is a state machine. States are enumerated in enum
591 * cl_page_state. Possible state transitions are enumerated in
592 * cl_page_state_set(). State transition process (i.e., actual changing of
593 * cl_page::cp_state field) is protected by the lock on the underlying VM
596 * Linux Kernel implementation.
598 * Binding between cl_page and struct page (which is a typedef for
599 * struct page) is implemented in the vvp layer. cl_page is attached to the
600 * ->private pointer of the struct page, together with the setting of
601 * PG_private bit in page->flags, and acquiring additional reference on the
602 * struct page (much like struct buffer_head, or any similar file system
603 * private data structures).
605 * PG_locked lock is used to implement both ownership and transfer
606 * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}}
607 * states. No additional references are acquired for the duration of the
610 * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where
611 * write-out is "protected" by the special PG_writeback bit.
615 * States of cl_page. cl_page.c assumes particular order here.
617 * The page state machine is rather crude, as it doesn't recognize finer page
618 * states like "dirty" or "up to date". This is because such states are not
619 * always well defined for the whole stack (see, for example, the
620 * implementation of the read-ahead, that hides page up-to-dateness to track
621 * cache hits accurately). Such sub-states are maintained by the layers that
622 * are interested in them.
626 * Page is in the cache, un-owned. Page leaves cached state in the
629 * - [cl_page_state::CPS_OWNED] io comes across the page and
632 * - [cl_page_state::CPS_PAGEOUT] page is dirty, the
633 * req-formation engine decides that it wants to include this page
634 * into an RPC being constructed, and yanks it from the cache;
636 * - [cl_page_state::CPS_FREEING] VM callback is executed to
637 * evict the page form the memory;
639 * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL
643 * Page is exclusively owned by some cl_io. Page may end up in this
644 * state as a result of
646 * - io creating new page and immediately owning it;
648 * - [cl_page_state::CPS_CACHED] io finding existing cached page
651 * - [cl_page_state::CPS_OWNED] io finding existing owned page
652 * and waiting for owner to release the page;
654 * Page leaves owned state in the following cases:
656 * - [cl_page_state::CPS_CACHED] io decides to leave the page in
657 * the cache, doing nothing;
659 * - [cl_page_state::CPS_PAGEIN] io starts read transfer for
662 * - [cl_page_state::CPS_PAGEOUT] io starts immediate write
663 * transfer for this page;
665 * - [cl_page_state::CPS_FREEING] io decides to destroy this
666 * page (e.g., as part of truncate or extent lock cancellation).
668 * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL
672 * Page is being written out, as a part of a transfer. This state is
673 * entered when req-formation logic decided that it wants this page to
674 * be sent through the wire _now_. Specifically, it means that once
675 * this state is achieved, transfer completion handler (with either
676 * success or failure indication) is guaranteed to be executed against
677 * this page independently of any locks and any scheduling decisions
678 * made by the hosting environment (that effectively means that the
679 * page is never put into cl_page_state::CPS_PAGEOUT state "in
680 * advance". This property is mentioned, because it is important when
681 * reasoning about possible dead-locks in the system). The page can
682 * enter this state as a result of
684 * - [cl_page_state::CPS_OWNED] an io requesting an immediate
685 * write-out of this page, or
687 * - [cl_page_state::CPS_CACHED] req-forming engine deciding
688 * that it has enough dirty pages cached to issue a "good"
691 * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer
692 * is completed---it is moved into cl_page_state::CPS_CACHED state.
694 * Underlying VM page is locked for the duration of transfer.
696 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
700 * Page is being read in, as a part of a transfer. This is quite
701 * similar to the cl_page_state::CPS_PAGEOUT state, except that
702 * read-in is always "immediate"---there is no such thing a sudden
703 * construction of read request from cached, presumably not up to date,
706 * Underlying VM page is locked for the duration of transfer.
708 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
712 * Page is being destroyed. This state is entered when client decides
713 * that page has to be deleted from its host object, as, e.g., a part
716 * Once this state is reached, there is no way to escape it.
718 * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL
725 /** Host page, the page is from the host inode which the cl_page
730 /** Transient page, the transient cl_page is used to bind a cl_page
731 * to vmpage which is not belonging to the same object of cl_page.
732 * it is used in DirectIO and lockless IO.
738 #define CP_STATE_BITS 4
739 #define CP_TYPE_BITS 2
740 #define CP_MAX_LAYER 2
743 * Fields are protected by the lock on struct page, except for atomics and
746 * \invariant Data type invariants are in cl_page_invariant(). Basically:
747 * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked
748 * list, consistent with the parent/child pointers in the cl_page::cp_obj and
749 * cl_page::cp_owner (when set).
752 /** Reference counter. */
754 /** layout_entry + stripe index, composed using lov_comp_index() */
755 unsigned int cp_lov_index;
756 /** page->index of the page within the whole file */
757 pgoff_t cp_page_index;
758 /** An object this page is a part of. Immutable after creation. */
759 struct cl_object *cp_obj;
761 struct page *cp_vmpage;
763 * Assigned if doing direct IO, because in this case cp_vmpage is not
764 * a valid page cache page, hence the inode cannot be inferred from
765 * cp_vmpage->mapping->host.
767 struct inode *cp_inode;
768 /** Linkage of pages within group. Pages must be owned */
769 struct list_head cp_batch;
770 /** array of slices offset. Immutable after creation. */
771 unsigned char cp_layer_offset[CP_MAX_LAYER];
772 /** current slice index */
773 unsigned char cp_layer_count:2;
775 * Page state. This field is const to avoid accidental update, it is
776 * modified only internally within cl_page.c. Protected by a VM lock.
778 enum cl_page_state cp_state:CP_STATE_BITS;
780 * Page type. Only CPT_TRANSIENT is used so far. Immutable after
783 enum cl_page_type cp_type:CP_TYPE_BITS;
784 unsigned cp_defer_uptodate:1,
787 /* which slab kmem index this memory allocated from */
788 short int cp_kmem_index;
791 * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned
792 * by sub-io. Protected by a VM lock.
794 struct cl_io *cp_owner;
795 /** List of references to this page, for debugging. */
796 struct lu_ref cp_reference;
797 /** Link to an object, for debugging. */
798 struct lu_ref_link cp_obj_ref;
799 /** Link to a queue, for debugging. */
800 struct lu_ref_link cp_queue_ref;
801 /** Assigned if doing a sync_io */
802 struct cl_sync_io *cp_sync_io;
806 * Per-layer part of cl_page.
808 * \see vvp_page, lov_page, osc_page
810 struct cl_page_slice {
811 struct cl_page *cpl_page;
812 const struct cl_page_operations *cpl_ops;
816 * Lock mode. For the client extent locks.
828 * Requested transfer type.
837 * Per-layer page operations.
839 * Methods taking an \a io argument are for the activity happening in the
840 * context of given \a io. Page is assumed to be owned by that io, except for
843 * \see vvp_page_ops, lov_page_ops, osc_page_ops
845 struct cl_page_operations {
847 * cl_page<->struct page methods. Only one layer in the stack has to
848 * implement these. Current code assumes that this functionality is
849 * provided by the topmost layer, see __cl_page_disown() as an example.
853 * Update file attributes when all we have is this page. Used for tiny
854 * writes to update attributes when we don't have a full cl_io.
856 void (*cpo_page_touch)(const struct lu_env *env,
857 const struct cl_page_slice *slice, size_t to);
863 * Called when page is truncated from the object. Optional.
865 * \see cl_page_discard()
866 * \see vvp_page_discard(), osc_page_discard()
868 void (*cpo_discard)(const struct lu_env *env,
869 const struct cl_page_slice *slice,
872 * Called when page is removed from the cache, and is about to being
873 * destroyed. Optional.
875 * \see cl_page_delete()
876 * \see vvp_page_delete(), osc_page_delete()
878 void (*cpo_delete)(const struct lu_env *env,
879 const struct cl_page_slice *slice);
881 * Optional debugging helper. Prints given page slice.
883 * \see cl_page_print()
885 int (*cpo_print)(const struct lu_env *env,
886 const struct cl_page_slice *slice,
887 void *cookie, lu_printer_t p);
895 * Request type dependent vector of operations.
897 * Transfer operations depend on transfer mode (cl_req_type). To avoid
898 * passing transfer mode to each and every of these methods, and to
899 * avoid branching on request type inside of the methods, separate
900 * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
901 * provided. That is, method invocation usually looks like
903 * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
907 * Completion handler. This is guaranteed to be eventually
908 * fired after cl_page_prep() or cl_page_make_ready() call.
910 * This method can be called in a non-blocking context. It is
911 * guaranteed however, that the page involved and its object
912 * are pinned in memory (and, hence, calling cl_page_put() is
915 * \see cl_page_completion()
917 void (*cpo_completion)(const struct lu_env *env,
918 const struct cl_page_slice *slice,
922 * Tell transfer engine that only [to, from] part of a page should be
925 * This is used for immediate transfers.
927 * \todo XXX this is not very good interface. It would be much better
928 * if all transfer parameters were supplied as arguments to
929 * cl_io_operations::cio_submit() call, but it is not clear how to do
930 * this for page queues.
932 * \see cl_page_clip()
934 void (*cpo_clip)(const struct lu_env *env,
935 const struct cl_page_slice *slice, int from, int to);
937 * Write out a page by kernel. This is only called by ll_writepage
940 * \see cl_page_flush()
942 int (*cpo_flush)(const struct lu_env *env,
943 const struct cl_page_slice *slice,
948 * Helper macro, dumping detailed information about \a page into a log.
950 #define CL_PAGE_DEBUG(mask, env, page, format, ...) \
952 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
953 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
954 cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
955 CDEBUG(mask, format, ## __VA_ARGS__); \
960 * Helper macro, dumping shorter information about \a page into a log.
962 #define CL_PAGE_HEADER(mask, env, page, format, ...) \
964 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
965 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
966 cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
967 CDEBUG(mask, format, ## __VA_ARGS__); \
971 static inline struct page *cl_page_vmpage(const struct cl_page *page)
973 LASSERT(page->cp_vmpage != NULL);
974 return page->cp_vmpage;
977 static inline pgoff_t cl_page_index(const struct cl_page *cp)
979 return cl_page_vmpage(cp)->index;
983 * Check if a cl_page is in use.
985 * Client cache holds a refcount, this refcount will be dropped when
986 * the page is taken out of cache, see vvp_page_delete().
988 static inline bool __page_in_use(const struct cl_page *page, int refc)
990 return (refcount_read(&page->cp_ref) > refc + 1);
994 * Caller itself holds a refcount of cl_page.
996 #define cl_page_in_use(pg) __page_in_use(pg, 1)
998 * Caller doesn't hold a refcount.
1000 #define cl_page_in_use_noref(pg) __page_in_use(pg, 0)
1004 * Extent locking on the client.
1008 * The locking model of the new client code is built around
1012 * data-type representing an extent lock on a regular file. cl_lock is a
1013 * layered object (much like cl_object and cl_page), it consists of a header
1014 * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
1015 * cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
1017 * Typical cl_lock consists of one layer:
1019 * - lov_lock (lov specific data).
1021 * lov_lock contains an array of sub-locks. Each of these sub-locks is a
1022 * normal cl_lock: it has a header (struct cl_lock) and a list of layers:
1026 * Each sub-lock is associated with a cl_object (representing stripe
1027 * sub-object or the file to which top-level cl_lock is associated to), and is
1028 * linked into that cl_object::coh_locks. In this respect cl_lock is similar to
1029 * cl_object (that at lov layer also fans out into multiple sub-objects), and
1030 * is different from cl_page, that doesn't fan out (there is usually exactly
1031 * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
1032 * a "top-lock" and its lovsub-osc portion a "sub-lock".
1036 * cl_lock is a cacheless data container for the requirements of locks to
1037 * complete the IO. cl_lock is created before I/O starts and destroyed when the
1040 * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
1041 * to cl_lock at OSC layer. LDLM lock is still cacheable.
1043 * INTERFACE AND USAGE
1045 * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
1046 * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
1047 * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
1048 * consists of multiple sub cl_locks, each sub locks will be enqueued
1049 * correspondingly. At OSC layer, the lock enqueue request will tend to reuse
1050 * cached LDLM lock; otherwise a new LDLM lock will have to be requested from
1053 * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
1054 * method will be called for each layer to release the resource held by this
1055 * lock. At OSC layer, the reference count of LDLM lock, which is held at
1056 * clo_enqueue time, is released.
1058 * LDLM lock can only be canceled if there is no cl_lock using it.
1060 * Overall process of the locking during IO operation is as following:
1062 * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
1063 * is called on each layer. Responsibility of this method is to add locks,
1064 * needed by a given layer into cl_io.ci_lockset.
1066 * - once locks for all layers were collected, they are sorted to avoid
1067 * dead-locks (cl_io_locks_sort()), and enqueued.
1069 * - when all locks are acquired, IO is performed;
1071 * - locks are released after IO is complete.
1073 * Striping introduces major additional complexity into locking. The
1074 * fundamental problem is that it is generally unsafe to actively use (hold)
1075 * two locks on the different OST servers at the same time, as this introduces
1076 * inter-server dependency and can lead to cascading evictions.
1078 * Basic solution is to sub-divide large read/write IOs into smaller pieces so
1079 * that no multi-stripe locks are taken (note that this design abandons POSIX
1080 * read/write semantics). Such pieces ideally can be executed concurrently. At
1081 * the same time, certain types of IO cannot be sub-divived, without
1082 * sacrificing correctness. This includes:
1084 * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
1087 * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
1089 * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
1090 * buf is a part of memory mapped Lustre file, a lock or locks protecting buf
1091 * has to be held together with the usual lock on [offset, offset + count].
1093 * Interaction with DLM
1095 * In the expected setup, cl_lock is ultimately backed up by a collection of
1096 * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
1097 * implemented in osc layer, that also matches DLM events (ASTs, cancellation,
1098 * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
1099 * description of interaction with DLM.
1105 struct cl_lock_descr {
1106 /** Object this lock is granted for. */
1107 struct cl_object *cld_obj;
1108 /** Index of the first page protected by this lock. */
1110 /** Index of the last page (inclusive) protected by this lock. */
1112 /** Group ID, for group lock */
1115 enum cl_lock_mode cld_mode;
1117 * flags to enqueue lock. A combination of bit-flags from
1118 * enum cl_enq_flags.
1120 __u32 cld_enq_flags;
1123 #define DDESCR "%s(%d):[%lu, %lu]:%x"
1124 #define PDESCR(descr) \
1125 cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
1126 (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
1128 const char *cl_lock_mode_name(const enum cl_lock_mode mode);
1131 * Layered client lock.
1134 /** List of slices. Immutable after creation. */
1135 struct list_head cll_layers;
1136 /** lock attribute, extent, cl_object, etc. */
1137 struct cl_lock_descr cll_descr;
1141 * Per-layer part of cl_lock
1143 * \see lov_lock, osc_lock
1145 struct cl_lock_slice {
1146 struct cl_lock *cls_lock;
1147 /** Object slice corresponding to this lock slice. Immutable after
1150 struct cl_object *cls_obj;
1151 const struct cl_lock_operations *cls_ops;
1152 /** Linkage into cl_lock::cll_layers. Immutable after creation. */
1153 struct list_head cls_linkage;
1158 * \see lov_lock_ops, osc_lock_ops
1160 struct cl_lock_operations {
1162 * Attempts to enqueue the lock. Called top-to-bottom.
1164 * \retval 0 this layer has enqueued the lock successfully
1165 * \retval >0 this layer has enqueued the lock, but need to wait on
1166 * @anchor for resources
1167 * \retval -ve failure
1169 * \see lov_lock_enqueue(), osc_lock_enqueue()
1171 int (*clo_enqueue)(const struct lu_env *env,
1172 const struct cl_lock_slice *slice,
1173 struct cl_io *io, struct cl_sync_io *anchor);
1175 * Cancel a lock, release its DLM lock ref, while does not cancel the
1178 void (*clo_cancel)(const struct lu_env *env,
1179 const struct cl_lock_slice *slice);
1181 * Destructor. Frees resources and the slice.
1183 * \see lov_lock_fini(), osc_lock_fini()
1185 void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
1187 * Optional debugging helper. Prints given lock slice.
1189 int (*clo_print)(const struct lu_env *env, void *cookie,
1190 lu_printer_t p, const struct cl_lock_slice *slice);
1193 #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
1195 if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
1196 LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
1197 cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
1198 CDEBUG(mask, format, ## __VA_ARGS__); \
1202 #define CL_LOCK_ASSERT(expr, env, lock) do { \
1206 CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
1211 /** \addtogroup cl_page_list cl_page_list
1212 * Page list used to perform collective operations on a group of pages.
1214 * Pages are added to the list one by one. cl_page_list acquires a reference
1215 * for every page in it. Page list is used to perform collective operations on
1218 * - submit pages for an immediate transfer,
1220 * - own pages on behalf of certain io (waiting for each page in turn),
1224 * When list is finalized, it releases references on all pages it still has.
1226 * \todo XXX concurrency control.
1229 struct cl_page_list {
1231 struct list_head pl_pages;
1235 * A 2-queue of pages. A convenience data-type for common use case, 2-queue
1236 * contains an incoming page list and an outgoing page list.
1239 struct cl_page_list c2_qin;
1240 struct cl_page_list c2_qout;
1246 * cl_io represents a high level I/O activity like
1247 * read(2)/write(2)/truncate(2) system call, or cancellation of an extent
1250 * cl_io is a layered object, much like cl_{object,page,lock} but with one
1251 * important distinction. We want to minimize number of calls to the allocator
1252 * in the fast path, e.g., in the case of read(2) when everything is cached:
1253 * client already owns the lock over region being read, and data are cached
1254 * due to read-ahead. To avoid allocation of cl_io layers in such situations,
1255 * per-layer io state is stored in the session, associated with the io, see
1256 * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
1257 * by using free-lists, see cl_env_get().
1259 * There is a small predefined number of possible io types, enumerated in enum
1262 * cl_io is a state machine, that can be advanced concurrently by the multiple
1263 * threads. It is up to these threads to control the concurrency and,
1264 * specifically, to detect when io is done, and its state can be safely
1267 * For read/write io overall execution plan is as following:
1269 * (0) initialize io state through all layers;
1271 * (1) loop: prepare chunk of work to do
1273 * (2) call all layers to collect locks they need to process current chunk
1275 * (3) sort all locks to avoid dead-locks, and acquire them
1277 * (4) process the chunk: call per-page methods
1278 * cl_io_operations::cio_prepare_write(),
1279 * cl_io_operations::cio_commit_write() for write)
1285 * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
1286 * address allocation efficiency issues mentioned above), and returns with the
1287 * special error condition from per-page method when current sub-io has to
1288 * block. This causes io loop to be repeated, and lov switches to the next
1289 * sub-io in its cl_io_operations::cio_iter_init() implementation.
1294 /** read system call */
1296 /** write system call */
1298 /** truncate, utime system calls */
1300 /** get data version */
1303 * page fault handling
1307 * fsync system call handling
1308 * To write out a range of file
1312 * glimpse. An io context to acquire glimpse lock.
1316 * Miscellaneous io. This is used for occasional io activity that
1317 * doesn't fit into other types. Currently this is used for:
1319 * - cancellation of an extent lock. This io exists as a context
1320 * to write dirty pages from under the lock being canceled back
1323 * - VM induced page write-out. An io context for writing page out
1324 * for memory cleansing;
1326 * - grouplock. An io context to acquire group lock.
1328 * CIT_MISC io is used simply as a context in which locks and pages
1329 * are manipulated. Such io has no internal "process", that is,
1330 * cl_io_loop() is never called for it.
1335 * To give advice about access of a file
1339 * SEEK_HOLE/SEEK_DATA handling to search holes or data
1340 * across all file objects
1347 * States of cl_io state machine
1350 /** Not initialized. */
1354 /** IO iteration started. */
1358 /** Actual IO is in progress. */
1360 /** IO for the current iteration finished. */
1362 /** Locks released. */
1364 /** Iteration completed. */
1366 /** cl_io finalized. */
1371 * IO state private for a layer.
1373 * This is usually embedded into layer session data, rather than allocated
1376 * \see vvp_io, lov_io, osc_io
1378 struct cl_io_slice {
1379 struct cl_io *cis_io;
1380 /** corresponding object slice. Immutable after creation. */
1381 struct cl_object *cis_obj;
1382 /** io operations. Immutable after creation. */
1383 const struct cl_io_operations *cis_iop;
1385 * linkage into a list of all slices for a given cl_io, hanging off
1386 * cl_io::ci_layers. Immutable after creation.
1388 struct list_head cis_linkage;
1391 typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
1392 struct folio_batch *);
1394 struct cl_read_ahead {
1395 /* Maximum page index the readahead window will end.
1396 * This is determined DLM lock coverage, RPC and stripe boundary.
1397 * cra_end is included.
1399 pgoff_t cra_end_idx;
1400 /* optimal RPC size for this read, by pages */
1401 unsigned long cra_rpc_pages;
1402 /* Release callback. If readahead holds resources underneath, this
1403 * function should be called to release it.
1405 void (*cra_release)(const struct lu_env *env,
1406 struct cl_read_ahead *ra);
1408 /* Callback data for cra_release routine */
1412 /* whether lock is in contention */
1413 bool cra_contention;
1416 static inline void cl_read_ahead_release(const struct lu_env *env,
1417 struct cl_read_ahead *ra)
1419 if (ra->cra_release != NULL)
1420 ra->cra_release(env, ra);
1421 memset(ra, 0, sizeof(*ra));
1426 * Per-layer io operations.
1427 * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
1429 struct cl_io_operations {
1431 * Vector of io state transition methods for every io type.
1433 * \see cl_page_operations::io
1437 * Prepare io iteration at a given layer.
1439 * Called top-to-bottom at the beginning of each iteration of
1440 * "io loop" (if it makes sense for this type of io). Here
1441 * layer selects what work it will do during this iteration.
1443 * \see cl_io_operations::cio_iter_fini()
1445 int (*cio_iter_init)(const struct lu_env *env,
1446 const struct cl_io_slice *slice);
1448 * Finalize io iteration.
1450 * Called bottom-to-top at the end of each iteration of "io
1451 * loop". Here layers can decide whether IO has to be
1454 * \see cl_io_operations::cio_iter_init()
1456 void (*cio_iter_fini)(const struct lu_env *env,
1457 const struct cl_io_slice *slice);
1459 * Collect locks for the current iteration of io.
1461 * Called top-to-bottom to collect all locks necessary for
1462 * this iteration. This methods shouldn't actually enqueue
1463 * anything, instead it should post a lock through
1464 * cl_io_lock_add(). Once all locks are collected, they are
1465 * sorted and enqueued in the proper order.
1467 int (*cio_lock)(const struct lu_env *env,
1468 const struct cl_io_slice *slice);
1470 * Finalize unlocking.
1472 * Called bottom-to-top to finish layer specific unlocking
1473 * functionality, after generic code released all locks
1474 * acquired by cl_io_operations::cio_lock().
1476 void (*cio_unlock)(const struct lu_env *env,
1477 const struct cl_io_slice *slice);
1479 * Start io iteration.
1481 * Once all locks are acquired, called top-to-bottom to
1482 * commence actual IO. In the current implementation,
1483 * top-level vvp_io_{read,write}_start() does all the work
1484 * synchronously by calling generic_file_*(), so other layers
1485 * are called when everything is done.
1487 int (*cio_start)(const struct lu_env *env,
1488 const struct cl_io_slice *slice);
1490 * Called top-to-bottom at the end of io loop. Here layer
1491 * might wait for an unfinished asynchronous io.
1493 void (*cio_end)(const struct lu_env *env,
1494 const struct cl_io_slice *slice);
1496 * Called bottom-to-top to notify layers that read/write IO
1497 * iteration finished, with \a nob bytes transferred.
1499 void (*cio_advance)(const struct lu_env *env,
1500 const struct cl_io_slice *slice,
1503 * Called once per io, bottom-to-top to release io resources.
1505 void (*cio_fini)(const struct lu_env *env,
1506 const struct cl_io_slice *slice);
1510 * Submit pages from \a queue->c2_qin for IO, and move
1511 * successfully submitted pages into \a queue->c2_qout. Return
1512 * non-zero if failed to submit even the single page. If
1513 * submission failed after some pages were moved into \a
1514 * queue->c2_qout, completion callback with non-zero ioret is
1517 int (*cio_submit)(const struct lu_env *env,
1518 const struct cl_io_slice *slice,
1519 enum cl_req_type crt, struct cl_2queue *queue);
1521 * Queue async page for write.
1522 * The difference between cio_submit and cio_queue is that
1523 * cio_submit is for urgent request.
1525 int (*cio_commit_async)(const struct lu_env *env,
1526 const struct cl_io_slice *slice,
1527 struct cl_page_list *queue, int from, int to,
1530 * Release active extent.
1532 void (*cio_extent_release)(const struct lu_env *env,
1533 const struct cl_io_slice *slice);
1535 * Decide maximum read ahead extent
1537 * \pre io->ci_type == CIT_READ
1539 int (*cio_read_ahead)(const struct lu_env *env,
1540 const struct cl_io_slice *slice,
1541 pgoff_t start, struct cl_read_ahead *ra);
1544 * Reserve LRU slots before IO.
1546 int (*cio_lru_reserve)(const struct lu_env *env,
1547 const struct cl_io_slice *slice,
1548 loff_t pos, size_t bytes);
1550 * Optional debugging helper. Print given io slice.
1552 int (*cio_print)(const struct lu_env *env, void *cookie,
1553 lu_printer_t p, const struct cl_io_slice *slice);
1557 * Flags to lock enqueue procedure.
1562 * instruct server to not block, if conflicting lock is found. Instead
1563 * -EAGAIN is returned immediately.
1565 CEF_NONBLOCK = 0x00000001,
1567 * Tell lower layers this is a glimpse request, translated to
1568 * LDLM_FL_HAS_INTENT at LDLM layer.
1570 * Also, because glimpse locks never block other locks, we count this
1571 * as automatically compatible with other osc locks.
1572 * (see osc_lock_compatible)
1574 CEF_GLIMPSE = 0x00000002,
1576 * tell the server to instruct (though a flag in the blocking ast) an
1577 * owner of the conflicting lock, that it can drop dirty pages
1578 * protected by this lock, without sending them to the server.
1580 CEF_DISCARD_DATA = 0x00000004,
1582 * tell the sub layers that it must be a `real' lock. This is used for
1583 * mmapped-buffer locks, glimpse locks, manually requested locks
1584 * (LU_LADVISE_LOCKAHEAD) that must never be converted into lockless
1587 * \see vvp_mmap_locks(), cl_glimpse_lock, cl_request_lock().
1589 CEF_MUST = 0x00000008,
1591 * tell the sub layers that never request a `real' lock. This flag is
1592 * not used currently.
1594 * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
1595 * conversion policy: ci_lockreq describes generic information of lock
1596 * requirement for this IO, especially for locks which belong to the
1597 * object doing IO; however, lock itself may have precise requirements
1598 * that are described by the enqueue flags.
1600 CEF_NEVER = 0x00000010,
1602 * tell the dlm layer this is a speculative lock request
1603 * speculative lock requests are locks which are not requested as part
1604 * of an I/O operation. Instead, they are requested because we expect
1605 * to use them in the future. They are requested asynchronously at the
1608 * Currently used for asynchronous glimpse locks and manually requested
1609 * locks (LU_LADVISE_LOCKAHEAD).
1611 CEF_SPECULATIVE = 0x00000020,
1613 * enqueue a lock to test DLM lock existence.
1615 CEF_PEEK = 0x00000040,
1617 * Lock match only. Used by group lock in I/O as group lock
1618 * is known to exist.
1620 CEF_LOCK_MATCH = 0x00000080,
1622 * tell the DLM layer to lock only the requested range
1624 CEF_LOCK_NO_EXPAND = 0x00000100,
1626 * mask of enq_flags.
1628 CEF_MASK = 0x000001ff,
1632 * Link between lock and io. Intermediate structure is needed, because the
1633 * same lock can be part of multiple io's simultaneously.
1635 struct cl_io_lock_link {
1636 /** linkage into one of cl_lockset lists. */
1637 struct list_head cill_linkage;
1638 struct cl_lock cill_lock;
1639 /** optional destructor */
1640 void (*cill_fini)(const struct lu_env *env,
1641 struct cl_io_lock_link *link);
1643 #define cill_descr cill_lock.cll_descr
1646 * Lock-set represents a collection of locks, that io needs at a
1647 * time. Generally speaking, client tries to avoid holding multiple locks when
1650 * - holding extent locks over multiple ost's introduces the danger of
1651 * "cascading timeouts";
1653 * - holding multiple locks over the same ost is still dead-lock prone,
1654 * see comment in osc_lock_enqueue(),
1656 * but there are certain situations where this is unavoidable:
1658 * - O_APPEND writes have to take [0, EOF] lock for correctness;
1660 * - truncate has to take [new-size, EOF] lock for correctness;
1662 * - SNS has to take locks across full stripe for correctness;
1664 * - in the case when user level buffer, supplied to {read,write}(file0),
1665 * is a part of a memory mapped lustre file, client has to take a dlm
1666 * locks on file0, and all files that back up the buffer (or a part of
1667 * the buffer, that is being processed in the current chunk, in any
1668 * case, there are situations where at least 2 locks are necessary).
1670 * In such cases we at least try to take locks in the same consistent
1671 * order. To this end, all locks are first collected, then sorted, and then
1675 /** locks to be acquired. */
1676 struct list_head cls_todo;
1677 /** locks acquired. */
1678 struct list_head cls_done;
1682 * Lock requirements(demand) for IO. It should be cl_io_lock_req,
1683 * but 'req' is always to be thought as 'request' :-)
1685 enum cl_io_lock_dmd {
1686 /** Always lock data (e.g., O_APPEND). */
1688 /** Layers are free to decide between local and global locking. */
1690 /** Never lock: there is no cache (e.g., liblustre). */
1694 enum cl_fsync_mode {
1695 /** start writeback, do not wait for them to finish */
1697 /** start writeback and wait for them to finish */
1699 /** discard all of dirty pages in a specific file range */
1700 CL_FSYNC_DISCARD = 2,
1701 /** start writeback and make sure they have reached storage before
1702 * return. OST_SYNC RPC must be issued and finished
1705 /** start writeback, thus the kernel can reclaim some memory */
1706 CL_FSYNC_RECLAIM = 4,
1709 struct cl_io_rw_common {
1714 enum cl_setattr_subtype {
1715 /** regular setattr **/
1719 /** fallocate(2) - mode preallocate **/
1720 CL_SETATTR_FALLOCATE
1723 struct cl_io_range {
1729 struct cl_io_pt *cip_next;
1730 struct kiocb cip_iocb;
1731 struct iov_iter cip_iter;
1732 struct file *cip_file;
1733 enum cl_io_type cip_iot;
1734 unsigned int cip_need_restart:1;
1743 * cl_io is shared by all threads participating in this IO (in current
1744 * implementation only one thread advances IO, but parallel IO design and
1745 * concurrent copy_*_user() require multiple threads acting on the same IO. It
1746 * is up to these threads to serialize their activities, including updates to
1747 * mutable cl_io fields.
1750 /** type of this IO. Immutable after creation. */
1751 enum cl_io_type ci_type;
1752 /** current state of cl_io state machine. */
1753 enum cl_io_state ci_state;
1754 /** main object this io is against. Immutable after creation. */
1755 struct cl_object *ci_obj;
1756 /** top level dio_aio */
1757 struct cl_dio_aio *ci_dio_aio;
1759 * Upper layer io, of which this io is a part of. Immutable after
1762 struct cl_io *ci_parent;
1763 /** List of slices. Immutable after creation. */
1764 struct list_head ci_layers;
1765 /** list of locks (to be) acquired by this io. */
1766 struct cl_lockset ci_lockset;
1767 /** lock requirements, this is just a help info for sublayers. */
1768 enum cl_io_lock_dmd ci_lockreq;
1769 /** layout version when this IO occurs */
1770 __u32 ci_layout_version;
1773 struct cl_io_rw_common rd;
1776 struct cl_io_rw_common wr;
1780 struct cl_io_rw_common ci_rw;
1781 struct cl_setattr_io {
1782 struct ost_lvb sa_attr;
1783 unsigned int sa_attr_flags;
1784 unsigned int sa_avalid; /* ATTR_* */
1785 unsigned int sa_xvalid; /* OP_XVALID */
1786 int sa_stripe_index;
1787 struct ost_layout sa_layout;
1788 const struct lu_fid *sa_parent_fid;
1789 /* SETATTR interface is used for regular setattr, */
1790 /* truncate(2) and fallocate(2) subtypes */
1791 enum cl_setattr_subtype sa_subtype;
1792 /* The following are used for fallocate(2) */
1794 loff_t sa_falloc_offset;
1795 loff_t sa_falloc_end;
1796 uid_t sa_falloc_uid;
1797 gid_t sa_falloc_gid;
1798 __u32 sa_falloc_projid;
1800 struct cl_data_version_io {
1801 u64 dv_data_version;
1802 u32 dv_layout_version;
1805 struct cl_fault_io {
1806 /** page index within file. */
1808 /** bytes valid byte on a faulted page. */
1810 /** writable page? for nopage() only */
1812 /** page of an executable? */
1814 /** page_mkwrite() */
1816 /** resulting page */
1817 struct cl_page *ft_page;
1819 struct cl_fsync_io {
1822 /** file system level fid */
1823 struct lu_fid *fi_fid;
1824 enum cl_fsync_mode fi_mode;
1825 /* how many pages were written/discarded */
1826 unsigned int fi_nr_written;
1828 struct cl_ladvise_io {
1831 /** file system level fid */
1832 struct lu_fid *lio_fid;
1833 enum lu_ladvise_type lio_advice;
1836 struct cl_lseek_io {
1842 time64_t lm_next_rpc_time;
1845 struct cl_2queue ci_queue;
1848 unsigned int ci_continue:1,
1850 * This io has held grouplock, to inform sublayers that
1851 * don't do lockless i/o.
1855 * The whole IO need to be restarted because layout has been changed
1859 * to not refresh layout - the IO issuer knows that the layout won't
1860 * change(page operations, layout change causes all page to be
1861 * discarded), or it doesn't matter if it changes(sync).
1865 * Need MDS intervention to complete a write.
1866 * Write intent is required for the following cases:
1867 * 1. component being written is not initialized, or
1868 * 2. the mirrored files are NOT in WRITE_PENDING state.
1870 ci_need_write_intent:1,
1872 * File is in PCC-RO state, need MDS intervention to complete
1873 * a data modifying operation.
1875 ci_need_pccro_clear:1,
1877 * Check if layout changed after the IO finishes. Mainly for HSM
1878 * requirement. If IO occurs to openning files, it doesn't need to
1879 * verify layout because HSM won't release openning files.
1880 * Right now, only two opertaions need to verify layout: glimpse
1885 * file is released, restore has to to be triggered by vvp layer
1887 ci_restore_needed:1,
1892 /* Tell sublayers not to expand LDLM locks requested for this IO */
1893 ci_lock_no_expand:1,
1895 * Set if non-delay RPC should be used for this IO.
1897 * If this file has multiple mirrors, and if the OSTs of the current
1898 * mirror is inaccessible, non-delay RPC would error out quickly so
1899 * that the upper layer can try to access the next mirror.
1903 * Set if IO is triggered by async workqueue readahead.
1905 ci_async_readahead:1,
1907 * Ignore lockless and do normal locking for this io.
1911 * Set if we've tried all mirrors for this read IO, if it's not set,
1912 * the read IO will check to-be-read OSCs' status, and make fast-switch
1913 * another mirror if some of the OSTs are not healthy.
1915 ci_tried_all_mirrors:1,
1917 * Random read hints, readahead will be disabled.
1921 * Sequential read hints.
1925 * Do parallel (async) submission of DIO RPCs. Note DIO is still sync
1926 * to userspace, only the RPCs are submitted async, then waited for at
1927 * the llite layer before returning.
1931 * this DIO is at least partly unaligned, and so the unaligned DIO
1932 * path is being used for this entire IO
1936 * there is a compat issue with unupgraded ZFS targets which means we
1937 * must refuse to do unaligned DIO to these targets, so this is used
1938 * to annotate that in the IO (since we learn if there is a problematic
1939 * OST/MDT target as we build the IO)
1941 ci_allow_unaligned_dio:1,
1943 * Bypass quota check
1947 * io_uring direct IO with flags IOCB_NOWAIT.
1951 * The filesystem must exclusively acquire invalidate_lock before
1952 * invalidating page cache in truncate / hole punch / DLM extent
1953 * lock blocking AST path (and thus calling into ->invalidatepage)
1954 * to block races between page cache invalidation and page cache
1955 * filling functions (fault, read, ...)
1957 ci_invalidate_page_cache:1,
1958 /* was this IO switched from BIO to DIO for hybrid IO? */
1959 ci_hybrid_switched:1;
1962 * How many times the read has retried before this one.
1963 * Set by the top level and consumed by the LOV.
1965 unsigned int ci_ndelay_tried;
1967 * Designated mirror index for this I/O.
1969 unsigned int ci_designated_mirror;
1971 * Number of pages owned by this IO. For invariant checking.
1973 unsigned int ci_owned_nr;
1975 * Range of write intent. Valid if ci_need_write_intent is set.
1977 struct lu_extent ci_write_intent;
1981 * Per-transfer attributes.
1983 struct cl_req_attr {
1984 enum cl_req_type cra_type;
1986 struct cl_page *cra_page;
1987 /** Generic attributes for the server consumption. */
1988 struct obdo *cra_oa;
1990 char cra_jobid[LUSTRE_JOBID_SIZE];
1991 /** uid/gid of the process doing an io */
1996 enum cache_stats_item {
1997 /** how many cache lookups were performed */
1999 /** how many times cache lookup resulted in a hit */
2001 /** how many entities are in the cache right now */
2003 /** how many entities in the cache are actively used (and cannot be
2004 * evicted) right now
2007 /** how many entities were created at all */
2012 #define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
2015 * Stats for a generic cache (similar to inode, lu_object, etc. caches).
2017 struct cache_stats {
2018 const char *cs_name;
2019 atomic_t cs_stats[CS_NR];
2022 /** These are not exported so far */
2023 void cache_stats_init(struct cache_stats *cs, const char *name);
2026 * Client-side site. This represents particular client stack. "Global"
2027 * variables should (directly or indirectly) be added here to allow multiple
2028 * clients to co-exist in the single address space.
2031 struct lu_site cs_lu;
2033 * Statistical counters. Atomics do not scale, something better like
2034 * per-cpu counters is needed.
2036 * These are exported as /proc/fs/lustre/llite/.../site
2038 * When interpreting keep in mind that both sub-locks (and sub-pages)
2039 * and top-locks (and top-pages) are accounted here.
2041 struct cache_stats cs_pages;
2042 atomic_t cs_pages_state[CPS_NR];
2045 int cl_site_init(struct cl_site *s, struct cl_device *top);
2046 void cl_site_fini(struct cl_site *s);
2047 void cl_stack_fini(const struct lu_env *env, struct cl_device *cl);
2050 * Output client site statistical counters into a buffer. Suitable for
2051 * ll_rd_*()-style functions.
2053 int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
2058 * Type conversion and accessory functions.
2061 static inline struct cl_site *lu2cl_site(const struct lu_site *site)
2063 return container_of(site, struct cl_site, cs_lu);
2066 static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
2068 LASSERT(d == NULL || IS_ERR(d) || lu_device_is_cl(d));
2069 return container_of_safe(d, struct cl_device, cd_lu_dev);
2072 static inline struct lu_device *cl2lu_dev(struct cl_device *d)
2074 return &d->cd_lu_dev;
2077 static inline struct cl_object *lu2cl(const struct lu_object *o)
2079 LASSERT(o == NULL || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
2080 return container_of_safe(o, struct cl_object, co_lu);
2083 static inline const struct cl_object_conf *
2084 lu2cl_conf(const struct lu_object_conf *conf)
2086 return container_of_safe(conf, struct cl_object_conf, coc_lu);
2089 static inline struct cl_object *cl_object_next(const struct cl_object *obj)
2091 return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL;
2094 static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
2096 return container_of_safe(h, struct cl_object_header, coh_lu);
2099 static inline struct cl_site *cl_object_site(const struct cl_object *obj)
2101 return lu2cl_site(obj->co_lu.lo_dev->ld_site);
2105 struct cl_object_header *cl_object_header(const struct cl_object *obj)
2107 return luh2coh(obj->co_lu.lo_header);
2110 static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
2112 return lu_device_init(&d->cd_lu_dev, t);
2115 static inline void cl_device_fini(struct cl_device *d)
2117 lu_device_fini(&d->cd_lu_dev);
2120 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
2121 struct cl_object *obj,
2122 const struct cl_page_operations *ops);
2123 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
2124 struct cl_object *obj,
2125 const struct cl_lock_operations *ops);
2126 void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
2127 struct cl_object *obj, const struct cl_io_operations *ops);
2129 struct cl_object *cl_object_top(struct cl_object *o);
2130 struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
2131 const struct lu_fid *fid,
2132 const struct cl_object_conf *c);
2134 int cl_object_header_init(struct cl_object_header *h);
2135 void cl_object_header_fini(struct cl_object_header *h);
2136 void cl_object_put(const struct lu_env *env, struct cl_object *o);
2137 void cl_object_get(struct cl_object *o);
2138 void cl_object_attr_lock(struct cl_object *o);
2139 void cl_object_attr_unlock(struct cl_object *o);
2140 int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
2141 struct cl_attr *attr);
2142 int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
2143 const struct cl_attr *attr, unsigned int valid);
2144 void cl_object_dirty_for_sync(const struct lu_env *env, struct cl_object *obj);
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);
2161 int cl_object_inode_ops(const struct lu_env *env, struct cl_object *obj,
2162 enum coo_inode_opc opc, void *data);
2166 * Returns true, iff \a o0 and \a o1 are slices of the same object.
2168 static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
2170 return cl_object_header(o0) == cl_object_header(o1);
2173 static inline void cl_object_page_init(struct cl_object *clob, int size)
2175 clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
2176 cl_object_header(clob)->coh_page_bufsize += round_up(size, 8);
2177 WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
2180 static inline void *cl_object_page_slice(struct cl_object *clob,
2181 struct cl_page *page)
2183 return (void *)((char *)page + clob->co_slice_off);
2187 * Return refcount of cl_object.
2189 static inline int cl_object_refc(struct cl_object *clob)
2191 struct lu_object_header *header = clob->co_lu.lo_header;
2193 return atomic_read(&header->loh_ref);
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_batch_put(const struct lu_env *env, struct cl_page *page,
2209 struct folio_batch *fbatch);
2210 void cl_page_print(const struct lu_env *env, void *cookie,
2211 lu_printer_t printer, const struct cl_page *pg);
2212 void cl_page_header_print(const struct lu_env *env, void *cookie,
2213 lu_printer_t printer, const struct cl_page *pg);
2214 struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj);
2219 * Functions dealing with the ownership of page by io.
2222 int cl_page_own(const struct lu_env *env, struct cl_io *io,
2223 struct cl_page *page);
2224 int cl_page_own_try(const struct lu_env *env,
2225 struct cl_io *io, struct cl_page *page);
2226 void cl_page_assume(const struct lu_env *env,
2227 struct cl_io *io, struct cl_page *page);
2228 void cl_page_unassume(const struct lu_env *env,
2229 struct cl_io *io, struct cl_page *pg);
2230 void cl_page_disown(const struct lu_env *env, struct cl_io *io,
2231 struct cl_page *page);
2232 int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io);
2237 * Functions dealing with the preparation of a page for a transfer, and
2238 * tracking transfer state.
2240 int cl_page_prep(const struct lu_env *env, struct cl_io *io,
2241 struct cl_page *pg, enum cl_req_type crt);
2242 void cl_page_completion(const struct lu_env *env, struct cl_page *pg,
2243 enum cl_req_type crt, int ioret);
2244 int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
2245 enum cl_req_type crt);
2246 int cl_page_cache_add(const struct lu_env *env, struct cl_io *io,
2247 struct cl_page *pg, enum cl_req_type crt);
2248 void cl_page_clip(const struct lu_env *env, struct cl_page *pg,
2250 int cl_page_flush(const struct lu_env *env, struct cl_io *io,
2251 struct cl_page *pg);
2254 * \name helper routines
2255 * Functions to discard, delete and export a cl_page.
2257 void cl_page_discard(const struct lu_env *env, struct cl_io *io,
2258 struct cl_page *pg);
2259 void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
2260 void cl_page_touch(const struct lu_env *env, const struct cl_page *pg,
2262 void cl_lock_print(const struct lu_env *env, void *cookie,
2263 lu_printer_t printer, const struct cl_lock *lock);
2264 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2265 lu_printer_t printer,
2266 const struct cl_lock_descr *descr);
2269 * Data structure managing a client's cached pages. A count of
2270 * "unstable" pages is maintained, and an LRU of clean pages is
2271 * maintained. "unstable" pages are pages pinned by the ptlrpc
2272 * layer for recovery purposes.
2274 struct cl_client_cache {
2276 * # of client cache refcount
2277 * # of users (OSCs) + 2 (held by llite and lov)
2279 refcount_t ccc_users;
2281 * # of threads are doing shrinking
2283 unsigned int ccc_lru_shrinkers;
2285 * # of LRU entries available
2287 atomic_long_t ccc_lru_left;
2289 * List of entities(OSCs) for this LRU cache
2291 struct list_head ccc_lru;
2293 * Max # of LRU entries
2295 unsigned long ccc_lru_max;
2297 * Lock to protect ccc_lru list
2299 spinlock_t ccc_lru_lock;
2301 * Set if unstable check is enabled
2303 unsigned int ccc_unstable_check:1;
2305 * # of unstable pages for this mount point
2307 atomic_long_t ccc_unstable_nr;
2309 * Serialize max_cache_mb write operation
2311 struct mutex ccc_max_cache_mb_lock;
2314 * cl_cache functions
2316 struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
2317 void cl_cache_incref(struct cl_client_cache *cache);
2318 void cl_cache_decref(struct cl_client_cache *cache);
2321 int cl_lock_request(const struct lu_env *env, struct cl_io *io,
2322 struct cl_lock *lock);
2323 int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
2324 const struct cl_io *io);
2325 void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
2326 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
2327 const struct lu_device_type *dtype);
2328 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
2330 int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
2331 struct cl_lock *lock, struct cl_sync_io *anchor);
2332 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
2335 int cl_io_init(const struct lu_env *env, struct cl_io *io,
2336 enum cl_io_type iot, struct cl_object *obj);
2337 int cl_io_sub_init(const struct lu_env *env, struct cl_io *io,
2338 enum cl_io_type iot, struct cl_object *obj);
2339 int cl_io_rw_init(const struct lu_env *env, struct cl_io *io,
2340 enum cl_io_type iot, loff_t pos, size_t bytes);
2341 int cl_io_loop(const struct lu_env *env, struct cl_io *io);
2343 void cl_io_fini(const struct lu_env *env, struct cl_io *io);
2344 int cl_io_iter_init(const struct lu_env *env, struct cl_io *io);
2345 void cl_io_iter_fini(const struct lu_env *env, struct cl_io *io);
2346 int cl_io_lock(const struct lu_env *env, struct cl_io *io);
2347 void cl_io_unlock(const struct lu_env *env, struct cl_io *io);
2348 int cl_io_start(const struct lu_env *env, struct cl_io *io);
2349 void cl_io_end(const struct lu_env *env, struct cl_io *io);
2350 int cl_io_lock_add(const struct lu_env *env, struct cl_io *io,
2351 struct cl_io_lock_link *link);
2352 int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
2353 struct cl_lock_descr *descr);
2354 int cl_io_submit_rw(const struct lu_env *env, struct cl_io *io,
2355 enum cl_req_type iot, struct cl_2queue *queue);
2356 int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io,
2357 enum cl_req_type iot, struct cl_2queue *queue,
2359 int cl_io_commit_async(const struct lu_env *env, struct cl_io *io,
2360 struct cl_page_list *queue, int from, int to,
2362 void cl_io_extent_release(const struct lu_env *env, struct cl_io *io);
2363 int cl_io_lru_reserve(const struct lu_env *env, struct cl_io *io,
2364 loff_t pos, size_t bytes);
2365 int cl_io_read_ahead(const struct lu_env *env, struct cl_io *io,
2366 pgoff_t start, struct cl_read_ahead *ra);
2367 void cl_io_rw_advance(const struct lu_env *env, struct cl_io *io,
2371 * True, iff \a io is an O_APPEND write(2).
2373 static inline int cl_io_is_append(const struct cl_io *io)
2375 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
2378 static inline int cl_io_is_sync_write(const struct cl_io *io)
2380 return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
2383 static inline int cl_io_is_mkwrite(const struct cl_io *io)
2385 return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
2389 * True, iff \a io is a truncate(2).
2391 static inline int cl_io_is_trunc(const struct cl_io *io)
2393 return io->ci_type == CIT_SETATTR &&
2394 (io->u.ci_setattr.sa_avalid & ATTR_SIZE) &&
2395 (io->u.ci_setattr.sa_subtype != CL_SETATTR_FALLOCATE);
2398 static inline int cl_io_is_fallocate(const struct cl_io *io)
2400 return (io->ci_type == CIT_SETATTR) &&
2401 (io->u.ci_setattr.sa_subtype == CL_SETATTR_FALLOCATE);
2404 struct cl_io *cl_io_top(struct cl_io *io);
2406 #define CL_IO_SLICE_CLEAN(obj, base) memset_startat(obj, 0, base)
2410 * Last page in the page list.
2412 static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
2414 LASSERT(plist->pl_nr > 0);
2415 return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
2418 static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
2420 LASSERT(plist->pl_nr > 0);
2421 return list_first_entry(&plist->pl_pages, struct cl_page, cp_batch);
2425 * Iterate over pages in a page list.
2427 #define cl_page_list_for_each(page, list) \
2428 list_for_each_entry((page), &(list)->pl_pages, cp_batch)
2431 * Iterate over pages in a page list, taking possible removals into account.
2433 #define cl_page_list_for_each_safe(page, temp, list) \
2434 list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
2436 void cl_page_list_init(struct cl_page_list *plist);
2437 void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page,
2439 void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src,
2440 struct cl_page *page);
2441 void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
2442 struct cl_page *page);
2443 void cl_page_list_splice(struct cl_page_list *list,
2444 struct cl_page_list *head);
2445 void cl_page_list_del(const struct lu_env *env,
2446 struct cl_page_list *plist, struct cl_page *page,
2448 void cl_page_list_disown(const struct lu_env *env,
2449 struct cl_page_list *plist);
2450 void cl_page_list_assume(const struct lu_env *env,
2451 struct cl_io *io, struct cl_page_list *plist);
2452 void cl_page_list_discard(const struct lu_env *env,
2453 struct cl_io *io, struct cl_page_list *plist);
2454 void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist);
2456 void cl_2queue_init(struct cl_2queue *queue);
2457 void cl_2queue_disown(const struct lu_env *env, struct cl_2queue *queue);
2458 void cl_2queue_assume(const struct lu_env *env, struct cl_io *io,
2459 struct cl_2queue *queue);
2460 void cl_2queue_discard(const struct lu_env *env, struct cl_io *io,
2461 struct cl_2queue *queue);
2462 void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue);
2463 void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
2465 void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
2466 struct cl_req_attr *attr);
2473 typedef void (cl_sync_io_end_t)(const struct lu_env *, struct cl_sync_io *);
2475 void cl_sync_io_init_notify(struct cl_sync_io *anchor, int nr, void *dio_aio,
2476 cl_sync_io_end_t *end);
2478 int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
2480 void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
2482 int cl_sync_io_wait_recycle(const struct lu_env *env, struct cl_sync_io *anchor,
2483 long timeout, int ioret);
2484 struct cl_dio_aio *cl_dio_aio_alloc(struct kiocb *iocb, struct cl_object *obj,
2486 struct cl_sub_dio *cl_sub_dio_alloc(struct cl_dio_aio *ll_aio,
2487 struct iov_iter *iter, bool write,
2488 bool unaligned, bool sync);
2489 void cl_dio_aio_free(const struct lu_env *env, struct cl_dio_aio *aio);
2490 void cl_sub_dio_free(struct cl_sub_dio *sdio);
2491 static inline void cl_sync_io_init(struct cl_sync_io *anchor, int nr)
2493 cl_sync_io_init_notify(anchor, nr, NULL, NULL);
2497 * Anchor for synchronous transfer. This is allocated on a stack by thread
2498 * doing synchronous transfer, and a pointer to this structure is set up in
2499 * every page submitted for transfer. Transfer completion routine updates
2500 * anchor and wakes up waiting thread when transfer is complete.
2503 /** number of pages yet to be transferred. */
2504 atomic_t csi_sync_nr;
2505 /** has this i/o completed? */
2506 atomic_t csi_complete;
2509 /** completion to be signaled when transfer is complete. */
2510 wait_queue_head_t csi_waitq;
2511 /** callback to invoke when this IO is finished */
2512 cl_sync_io_end_t *csi_end_io;
2513 /* private pointer for an associated DIO/AIO */
2517 /** direct IO pages */
2518 struct ll_dio_pages {
2520 * page array for RDMA - for aligned i/o, this is the user provided
2521 * pages, but for unaligned i/o, this is the internal buffer
2523 struct page **ldp_pages;
2524 /** # of pages in the array. */
2526 /* the file offset of the first page. */
2527 loff_t ldp_file_offset;
2530 /* Top level struct used for AIO and DIO */
2532 struct cl_sync_io cda_sync;
2533 struct cl_object *cda_obj;
2534 struct kiocb *cda_iocb;
2536 struct mm_struct *cda_mm;
2537 unsigned cda_no_aio_complete:1,
2541 /* Sub-dio used for splitting DIO (and AIO, because AIO is DIO) according to
2542 * the layout/striping, so we can do parallel submit of DIO RPCs
2545 struct cl_sync_io csd_sync;
2546 struct cl_page_list csd_pages;
2548 struct cl_dio_aio *csd_ll_aio;
2549 struct ll_dio_pages csd_dio_pages;
2550 struct iov_iter csd_iter;
2551 unsigned csd_creator_free:1,
2555 #if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW) || \
2556 defined(HAVE_DIRECTIO_2ARGS)
2557 #define HAVE_DIO_ITER 1
2560 void ll_release_user_pages(struct page **pages, int npages);
2561 int ll_allocate_dio_buffer(struct ll_dio_pages *pvec, size_t io_size);
2562 void ll_free_dio_buffer(struct ll_dio_pages *pvec);
2563 ssize_t ll_dio_user_copy(struct cl_sub_dio *sdio, struct iov_iter *write_iov);
2565 #ifndef HAVE_KTHREAD_USE_MM
2566 #define kthread_use_mm(mm) use_mm(mm)
2567 #define kthread_unuse_mm(mm) unuse_mm(mm)
2570 /** \defgroup cl_env cl_env
2572 * lu_env handling for a client.
2574 * lu_env is an environment within which lustre code executes. Its major part
2575 * is lu_context---a fast memory allocation mechanism that is used to conserve
2576 * precious kernel stack space. Originally lu_env was designed for a server,
2579 * - there is a (mostly) fixed number of threads, and
2581 * - call chains have no non-lustre portions inserted between lustre code.
2583 * On a client both these assumtpion fails, because every user thread can
2584 * potentially execute lustre code as part of a system call, and lustre calls
2585 * into VFS or MM that call back into lustre.
2587 * To deal with that, cl_env wrapper functions implement the following
2590 * - allocation and destruction of environment is amortized by caching no
2591 * longer used environments instead of destroying them;
2593 * \see lu_env, lu_context, lu_context_key
2597 struct lu_env *cl_env_get(__u16 *refcheck);
2598 struct lu_env *cl_env_alloc(__u16 *refcheck, __u32 tags);
2599 void cl_env_put(struct lu_env *env, __u16 *refcheck);
2600 unsigned int cl_env_cache_purge(unsigned int nr);
2601 struct lu_env *cl_env_percpu_get(void);
2602 void cl_env_percpu_put(struct lu_env *env);
2608 void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr);
2609 void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
2611 struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
2612 struct lu_device_type *ldt,
2613 struct lu_device *next);
2615 int cl_global_init(void);
2616 void cl_global_fini(void);
2618 #endif /* _LINUX_CL_OBJECT_H */