Viewing: cl_object.h
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, 2017, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
*/
#ifndef _LUSTRE_CL_OBJECT_H
#define _LUSTRE_CL_OBJECT_H
/** \defgroup clio clio
*
* Client objects implement io operations and cache pages.
*
* Examples: lov and osc are implementations of cl interface.
*
* Big Theory Statement.
*
* Layered objects.
*
* Client implementation is based on the following data-types:
*
* - cl_object
*
* - cl_page
*
* - cl_lock represents an extent lock on an object.
*
* - cl_io represents high-level i/o activity such as whole read/write
* system call, or write-out of pages from under the lock being
* canceled. cl_io has sub-ios that can be stopped and resumed
* independently, thus achieving high degree of transfer
* parallelism. Single cl_io can be advanced forward by
* the multiple threads (although in the most usual case of
* read/write system call it is associated with the single user
* thread, that issued the system call).
*
* Terminology
*
* - to avoid confusion high-level I/O operation like read or write system
* call is referred to as "an io", whereas low-level I/O operation, like
* RPC, is referred to as "a transfer"
*
* - "generic code" means generic (not file system specific) code in the
* hosting environment. "cl-code" means code (mostly in cl_*.c files) that
* is not layer specific.
*
* Locking.
*
* - i_mutex
* - PG_locked
* - cl_object_header::coh_page_guard
* - lu_site::ls_guard
*
* See the top comment in cl_object.c for the description of overall locking and
* reference-counting design.
*
* See comments below for the description of i/o, page, and dlm-locking
* design.
*
*/
/*
* super-class definitions.
*/
#include <linux/aio.h>
#include <linux/fs.h>
#include <linux/atomic.h>
#include <linux/mutex.h>
#include <linux/radix-tree.h>
#include <linux/spinlock.h>
#include <lustre_compat/linux/string.h>
#include <linux/wait.h>
#include <linux/pagevec.h>
#include <lu_object.h>
#include <lustre_dlm.h>
#include <lustre_compat.h>
struct obd_info;
struct inode;
struct cl_device;
struct cl_object;
struct cl_page;
struct cl_page_slice;
struct cl_lock;
struct cl_lock_slice;
struct cl_lock_operations;
struct cl_page_operations;
struct cl_io;
struct cl_io_slice;
struct cl_req_attr;
/**
* Device in the client stack.
*
* \see vvp_device, lov_device, lovsub_device, osc_device
*/
struct cl_device {
/** Super-class. */
struct lu_device cd_lu_dev;
};
/* cl_object */
/**
* "Data attributes" of cl_object. Data attributes can be updated
* independently for a sub-object, and top-object's attributes are calculated
* from sub-objects' ones.
*/
struct cl_attr {
/** Object size, in bytes */
loff_t cat_size;
unsigned int cat_kms_valid:1;
/**
* Known minimal size, in bytes.
*
* This is only valid when at least one DLM lock is held.
*/
loff_t cat_kms;
/** Modification time. Measured in seconds since epoch. */
time64_t cat_mtime;
/** Access time. Measured in seconds since epoch. */
time64_t cat_atime;
/** Change time. Measured in seconds since epoch. */
time64_t cat_ctime;
/**
* Blocks allocated to this cl_object on the server file system.
*
* \todo XXX An interface for block size is needed.
*/
__u64 cat_blocks;
/**
* User identifier for quota purposes.
*/
uid_t cat_uid;
/**
* Group identifier for quota purposes.
*/
gid_t cat_gid;
/* nlink of the directory */
__u64 cat_nlink;
/* Project identifier for quota purpose. */
__u32 cat_projid;
};
/**
* Fields in cl_attr that are being set.
*/
enum cl_attr_valid {
CAT_SIZE = BIT(0),
CAT_KMS = BIT(1),
CAT_MTIME = BIT(3),
CAT_ATIME = BIT(4),
CAT_CTIME = BIT(5),
CAT_BLOCKS = BIT(6),
CAT_UID = BIT(7),
CAT_GID = BIT(8),
CAT_PROJID = BIT(9),
CAT_COMPRESSIBLE= BIT(10),
};
/**
* Sub-class of lu_object with methods common for objects on the client
* stacks.
*
* cl_object: represents a regular file system object, both a file and a
* stripe. cl_object is based on lu_object: it is identified by a fid,
* layered, cached, hashed, and lrued. Important distinction with the server
* side, where md_object and dt_object are used, is that cl_object "fans out"
* at the lov/sns level: depending on the file layout, single file is
* represented as a set of "sub-objects" (stripes). At the implementation
* level, struct lov_object contains an array of cl_objects. Each sub-object
* is a full-fledged cl_object, having its fid, living in the lru and hash
* table.
*
* This leads to the next important difference with the server side: on the
* client, it's quite usual to have objects with the different sequence of
* layers. For example, typical top-object is composed of the following
* layers:
*
* - vvp
* - lov
*
* whereas its sub-objects are composed of
*
* - lovsub
* - osc
*
* layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep
* track of the object-subobject relationship.
*
* Sub-objects are not cached independently: when top-object is about to
* be discarded from the memory, all its sub-objects are torn-down and
* destroyed too.
*
* \see vvp_object, lov_object, lovsub_object, osc_object
*/
struct cl_object {
/** super class */
struct lu_object co_lu;
/** per-object-layer operations */
const struct cl_object_operations *co_ops;
/** offset of page slice in cl_page buffer */
int co_slice_off;
};
/**
* Description of the client object configuration. This is used for the
* creation of a new client object that is identified by a more state than
* fid.
*/
struct cl_object_conf {
/** Super-class. */
struct lu_object_conf coc_lu;
union {
/**
* Object layout. This is consumed by lov.
*/
struct lu_buf coc_layout;
/**
* Description of particular stripe location in the
* cluster. This is consumed by osc.
*/
struct lov_oinfo *coc_oinfo;
} u;
/**
* VFS inode. This is consumed by vvp.
*/
struct inode *coc_inode;
/**
* Layout lock handle.
*/
struct ldlm_lock *coc_lock;
bool coc_try;
/**
* Operation to handle layout, OBJECT_CONF_XYZ.
*/
int coc_opc;
};
enum {
/** configure layout, new stripe, must must be holding layout lock. */
OBJECT_CONF_SET = 0,
/** invalidate the current stripe config when losing layout lock. */
OBJECT_CONF_INVALIDATE = 1,
/** wait for old layout to go away so that new layout can be set up. */
OBJECT_CONF_WAIT = 2
};
enum {
CL_LAYOUT_GEN_NONE = (u32)-2, /* layout lock was cancelled */
CL_LAYOUT_GEN_EMPTY = (u32)-1, /* for empty layout */
};
struct cl_layout {
/** the buffer to return the layout in lov_mds_md format. */
struct lu_buf cl_buf;
/** size of layout in lov_mds_md format. */
size_t cl_size;
/** Layout generation. */
u32 cl_layout_gen;
/** whether layout is a composite one */
bool cl_is_composite;
/** Whether layout is a HSM released one */
bool cl_is_released;
/** Whether layout is a readonly one */
bool cl_is_rdonly;
};
struct cl_dio_pages;
/**
* Operations implemented for each cl object layer.
*
* \see vvp_ops, lov_ops, lovsub_ops, osc_ops
*/
struct cl_object_operations {
/**
* Initialize page slice for this layer. Called top-to-bottom through
* every object layer when a new cl_page is instantiated. Layer
* keeping private per-page data, or requiring its own page operations
* vector should allocate these data here, and attach then to the page
* by calling cl_page_slice_add(). \a vmpage is locked (in the VM
* sense). Optional.
*
* \retval NULL success.
*
* \retval ERR_PTR(errno) failure code.
*
* \retval valid-pointer pointer to already existing referenced page
* to be used instead of newly created.
*/
int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj,
struct cl_page *page, pgoff_t index);
/**
* Initialize the dio pages structure with information from this layer
*
* Called top-to-bottom through every object layer to gather the
* per-layer information required for the dio, does the same job as
* coo_page_init but just once for each dio page array
*/
int (*coo_dio_pages_init)(const struct lu_env *env,
struct cl_object *obj,
struct cl_dio_pages *cdp,
pgoff_t index);
/**
* Initialize lock slice for this layer. Called top-to-bottom through
* every object layer when a new cl_lock is instantiated. Layer
* keeping private per-lock data, or requiring its own lock operations
* vector should allocate these data here, and attach then to the lock
* by calling cl_lock_slice_add(). Mandatory.
*/
int (*coo_lock_init)(const struct lu_env *env,
struct cl_object *obj, struct cl_lock *lock,
const struct cl_io *io);
/**
* Initialize io state for a given layer.
*
* called top-to-bottom once per io existence to initialize io
* state. If layer wants to keep some state for this type of io, it
* has to embed struct cl_io_slice in lu_env::le_ses, and register
* slice with cl_io_slice_add(). It is guaranteed that all threads
* participating in this io share the same session.
*/
int (*coo_io_init)(const struct lu_env *env,
struct cl_object *obj, struct cl_io *io);
/**
* Fill portion of \a attr that this layer controls. This method is
* called top-to-bottom through all object layers.
*
* \pre cl_object_header::coh_attr_guard of the top-object is locked.
*
* \return 0: to continue
* \return +ve: to stop iterating through layers (but 0 is returned
* from enclosing cl_object_attr_get())
* \return -ve: to signal error
*/
int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj,
struct cl_attr *attr);
/**
* Update attributes.
*
* \a valid is a bitmask composed from enum #cl_attr_valid, and
* indicating what attributes are to be set.
*
* \pre cl_object_header::coh_attr_guard of the top-object is locked.
*
* \return the same convention as for
* cl_object_operations::coo_attr_get() is used.
*/
int (*coo_attr_update)(const struct lu_env *env, struct cl_object *obj,
const struct cl_attr *attr,
enum cl_attr_valid valid);
/**
* Mark the inode dirty. By this way, the inode will add into the
* writeback list of the corresponding @bdi_writeback, and then it will
* defer to write out the dirty pages to OSTs via the kernel writeback
* mechanism.
*/
void (*coo_dirty_for_sync)(const struct lu_env *env,
struct cl_object *obj);
/**
* Update object configuration. Called top-to-bottom to modify object
* configuration.
*
* XXX error conditions and handling.
*/
int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj,
const struct cl_object_conf *conf);
/**
* Glimpse ast. Executed when glimpse ast arrives for a lock on this
* object. Layers are supposed to fill parts of \a lvb that will be
* shipped to the glimpse originator as a glimpse result.
*
* \see vvp_object_glimpse(), lovsub_object_glimpse(),
* \see osc_object_glimpse()
*/
int (*coo_glimpse)(const struct lu_env *env,
const struct cl_object *obj, struct ost_lvb *lvb);
/**
* Object prune method. Called when the layout is going to change on
* this object, therefore each layer has to clean up their cache,
* mainly pages and locks.
*/
int (*coo_prune)(const struct lu_env *env, struct cl_object *obj);
/**
* Object getstripe method.
*/
int (*coo_getstripe)(const struct lu_env *env, struct cl_object *obj,
struct lov_user_md __user *lum, size_t size);
/**
* Get FIEMAP mapping from the object.
*/
int (*coo_fiemap)(const struct lu_env *env, struct cl_object *obj,
struct ll_fiemap_info_key *fmkey,
struct fiemap *fiemap, size_t *buflen);
/**
* Get layout and generation of the object.
*/
int (*coo_layout_get)(const struct lu_env *env, struct cl_object *obj,
struct cl_layout *layout);
/**
* Get maximum size of the object.
*/
loff_t (*coo_maxbytes)(struct cl_object *obj);
/**
* Set request attributes.
*/
void (*coo_req_attr_set)(const struct lu_env *env,
struct cl_object *obj,
struct cl_req_attr *attr);
/**
* Flush \a obj data corresponding to \a lock. Used for DoM
* locks in llite's cancelling blocking ast callback.
*/
int (*coo_object_flush)(const struct lu_env *env,
struct cl_object *obj,
struct ldlm_lock *lock);
/**
* Get ProjID for a request.
*/
void (*coo_req_projid_set)(const struct lu_env *env,
struct cl_object *obj, __u32 *projid);
};
/**
* Extended header for client object.
*/
struct cl_object_header {
/* Standard lu_object_header. cl_object::co_lu::lo_header points here.*/
struct lu_object_header coh_lu;
/**
* Parent object. It is assumed that an object has a well-defined
* parent, but not a well-defined child (there may be multiple
* sub-objects, for the same top-object). cl_object_header::coh_parent
* field allows certain code to be written generically, without
* limiting possible cl_object layouts unduly.
*/
struct cl_object_header *coh_parent;
/**
* Protects consistency between cl_attr of parent object and
* attributes of sub-objects, that the former is calculated ("merged")
* from.
*
* \todo XXX this can be read/write lock if needed.
*/
spinlock_t coh_attr_guard;
/**
* Size of cl_page + page slices
*/
unsigned short coh_page_bufsize;
/**
* Number of objects above this one: 0 for a top-object, 1 for its
* sub-object, etc.
*/
unsigned char coh_nesting;
};
/**
* Helper macro: iterate over all layers of the object \a obj, assigning every
* layer top-to-bottom to \a slice.
*/
#define cl_object_for_each(slice, obj) \
list_for_each_entry((slice), \
&(obj)->co_lu.lo_header->loh_layers,\
co_lu.lo_linkage)
/**
* Helper macro: iterate over all layers of the object \a obj, assigning every
* layer bottom-to-top to \a slice.
*/
#define cl_object_for_each_reverse(slice, obj) \
list_for_each_entry_reverse((slice), \
&(obj)->co_lu.lo_header->loh_layers,\
co_lu.lo_linkage)
#define CL_PAGE_EOF ((pgoff_t)~0ull)
/** \struct cl_page
* Layered client page.
*
* cl_page: represents a portion of a file, cached in the memory. All pages
* of the given file are of the same size, and are kept in the radix tree
* hanging off the cl_object. cl_page doesn't fan out, but as sub-objects
* of the top-level file object are first class cl_objects, they have their
* own radix trees of pages and hence page is implemented as a sequence of
* struct cl_pages's, linked into double-linked list through
* cl_page::cp_parent and cl_page::cp_child pointers, each residing in the
* corresponding radix tree at the corresponding logical offset.
*
* cl_page is associated with VM page of the hosting environment (struct
* page in Linux kernel, for example), struct page. It is assumed, that this
* association is implemented by one of cl_page layers (top layer in the
* current design) that
*
* - intercepts per-VM-page call-backs made by the environment (e.g.,
* memory pressure),
*
* - translates state (page flag bits) and locking between lustre and
* environment.
*
* The association between cl_page and struct page is immutable and
* established when cl_page is created.
*
* cl_page can be "owned" by a particular cl_io (see below), guaranteeing
* this io an exclusive access to this page w.r.t. other io attempts and
* various events changing page state (such as transfer completion, or
* eviction of the page from the memory). Note, that in general cl_io
* cannot be identified with a particular thread, and page ownership is not
* exactly equal to the current thread holding a lock on the page. Layer
* implementing association between cl_page and struct page has to implement
* ownership on top of available synchronization mechanisms.
*
* While lustre client maintains the notion of an page ownership by io,
* hosting MM/VM usually has its own page concurrency control
* mechanisms. For example, in Linux, page access is synchronized by the
* per-page PG_locked bit-lock, and generic kernel code (generic_file_*())
* takes care to acquire and release such locks as necessary around the
* calls to the file system methods (->readpage(), ->prepare_write(),
* ->commit_write(), etc.). This leads to the situation when there are two
* different ways to own a page in the client:
*
* - client code explicitly and voluntary owns the page (cl_page_own());
*
* - VM locks a page and then calls the client, that has "to assume"
* the ownership from the VM (cl_page_assume()).
*
* Dual methods to release ownership are cl_page_disown() and
* cl_page_unassume().
*
* cl_page is reference counted (cl_page::cp_ref). When reference counter
* drops to 0, the page is returned to the cache, unless it is in
* cl_page_state::CPS_FREEING state, in which case it is immediately
* destroyed.
*
* The general logic guaranteeing the absence of "existential races" for
* pages is the following:
*
* - there are fixed known ways for a thread to obtain a new reference
* to a page:
*
* - by doing a lookup in the cl_object radix tree, protected by the
* spin-lock;
*
* - by starting from VM-locked struct page and following some
* hosting environment method (e.g., following ->private pointer in
* the case of Linux kernel), see cl_page_from_folio();
*
* - when the page enters cl_page_state::CPS_FREEING state, all these
* ways are severed with the proper synchronization
* (cl_page_delete());
*
* - entry into cl_page_state::CPS_FREEING is serialized by the VM page
* lock;
*
* - no new references to the page in cl_page_state::CPS_FREEING state
* are allowed (checked in cl_page_get()).
*
* Together this guarantees that when last reference to a
* cl_page_state::CPS_FREEING page is released, it is safe to destroy the
* page, as neither references to it can be acquired at that point, nor
* ones exist.
*
* cl_page is a state machine. States are enumerated in enum
* cl_page_state. Possible state transitions are enumerated in
* cl_page_state_set(). State transition process (i.e., actual changing of
* cl_page::cp_state field) is protected by the lock on the underlying VM
* page.
*
* Linux Kernel implementation.
*
* Binding between cl_page and struct page (which is a typedef for
* struct page) is implemented in the vvp layer. cl_page is attached to the
* ->private pointer of the struct page, together with the setting of
* PG_private bit in page->flags, and acquiring additional reference on the
* struct page (much like struct buffer_head, or any similar file system
* private data structures).
*
* PG_locked lock is used to implement both ownership and transfer
* synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}}
* states. No additional references are acquired for the duration of the
* transfer.
*
* \warning *THIS IS NOT* the behavior expected by the Linux kernel, where
* write-out is "protected" by the special PG_writeback bit.
*/
/**
* States of cl_page. cl_page.c assumes particular order here.
*
* The page state machine is rather crude, as it doesn't recognize finer page
* states like "dirty" or "up to date". This is because such states are not
* always well defined for the whole stack (see, for example, the
* implementation of the read-ahead, that hides page up-to-dateness to track
* cache hits accurately). Such sub-states are maintained by the layers that
* are interested in them.
*/
enum cl_page_state {
/**
* Page is in the cache, un-owned. Page leaves cached state in the
* following cases:
*
* - [cl_page_state::CPS_OWNED] io comes across the page and
* owns it;
*
* - [cl_page_state::CPS_PAGEOUT] page is dirty, the
* req-formation engine decides that it wants to include this page
* into an RPC being constructed, and yanks it from the cache;
*
* - [cl_page_state::CPS_FREEING] VM callback is executed to
* evict the page form the memory;
*
* \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL
*/
CPS_CACHED = 1,
/**
* Page is exclusively owned by some cl_io. Page may end up in this
* state as a result of
*
* - io creating new page and immediately owning it;
*
* - [cl_page_state::CPS_CACHED] io finding existing cached page
* and owning it;
*
* - [cl_page_state::CPS_OWNED] io finding existing owned page
* and waiting for owner to release the page;
*
* Page leaves owned state in the following cases:
*
* - [cl_page_state::CPS_CACHED] io decides to leave the page in
* the cache, doing nothing;
*
* - [cl_page_state::CPS_PAGEIN] io starts read transfer for
* this page;
*
* - [cl_page_state::CPS_PAGEOUT] io starts immediate write
* transfer for this page;
*
* - [cl_page_state::CPS_FREEING] io decides to destroy this
* page (e.g., as part of truncate or extent lock cancellation).
*
* \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL
*/
CPS_OWNED,
/**
* Page is being written out, as a part of a transfer. This state is
* entered when req-formation logic decided that it wants this page to
* be sent through the wire _now_. Specifically, it means that once
* this state is achieved, transfer completion handler (with either
* success or failure indication) is guaranteed to be executed against
* this page independently of any locks and any scheduling decisions
* made by the hosting environment (that effectively means that the
* page is never put into cl_page_state::CPS_PAGEOUT state "in
* advance". This property is mentioned, because it is important when
* reasoning about possible dead-locks in the system). The page can
* enter this state as a result of
*
* - [cl_page_state::CPS_OWNED] an io requesting an immediate
* write-out of this page, or
*
* - [cl_page_state::CPS_CACHED] req-forming engine deciding
* that it has enough dirty pages cached to issue a "good"
* transfer.
*
* The page leaves cl_page_state::CPS_PAGEOUT state when the transfer
* is completed---it is moved into cl_page_state::CPS_CACHED state.
*
* Underlying VM page is locked for the duration of transfer.
*
* \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
*/
CPS_PAGEOUT,
/**
* Page is being read in, as a part of a transfer. This is quite
* similar to the cl_page_state::CPS_PAGEOUT state, except that
* read-in is always "immediate"---there is no such thing a sudden
* construction of read request from cached, presumably not up to date,
* pages.
*
* Underlying VM page is locked for the duration of transfer.
*
* \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL
*/
CPS_PAGEIN,
/**
* Page is being destroyed. This state is entered when client decides
* that page has to be deleted from its host object, as, e.g., a part
* of truncate.
*
* Once this state is reached, there is no way to escape it.
*
* \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL
*/
CPS_FREEING,
CPS_NR
};
enum cl_page_type {
/** Host page, the page is from the host inode which the cl_page
* belongs to.
*/
CPT_CACHEABLE = 1,
/** Transient page, the transient cl_page is used to bind a cl_page
* to vmpage which is not belonging to the same object of cl_page.
* it is used in DirectIO and lockless IO.
*/
CPT_TRANSIENT,
CPT_NR
};
#define CP_STATE_BITS 4
#define CP_TYPE_BITS 2
#define CP_MAX_LAYER 2
/**
* Fields are protected by the lock on struct page, except for atomics and
* immutables.
*
* \invariant Data type invariants are in cl_page_invariant(). Basically:
* cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked
* list, consistent with the parent/child pointers in the cl_page::cp_obj and
* cl_page::cp_owner (when set).
*/
struct cl_page {
/** Reference counter. */
refcount_t cp_ref;
/** layout_entry + stripe index, composed using lov_comp_index() */
unsigned int cp_lov_index;
/** page->index of the page within the whole file */
pgoff_t cp_page_index;
/** An object this page is a part of. Immutable after creation. */
struct cl_object *cp_obj;
/** vmpage */
struct page *cp_vmpage;
/**
* Assigned if doing direct IO, because in this case cp_vmpage is not
* a valid page cache page, hence the inode cannot be inferred from
* cp_vmpage->mapping->host.
*/
struct inode *cp_inode;
/** Linkage of pages within group. Pages must be owned */
struct list_head cp_batch;
/** array of slices offset. Immutable after creation. */
unsigned char cp_layer_offset[CP_MAX_LAYER];
/** current slice index */
unsigned char cp_layer_count:2;
/**
* Page state. This field is const to avoid accidental update, it is
* modified only internally within cl_page.c. Protected by a VM lock.
*/
enum cl_page_state cp_state:CP_STATE_BITS;
/**
* Page type. Only CPT_TRANSIENT is used so far. Immutable after
* creation.
*/
enum cl_page_type cp_type:CP_TYPE_BITS;
unsigned cp_defer_uptodate:1,
cp_ra_updated:1,
cp_ra_used:1,
cp_in_kmem_array:1;
union {
/* which slab kmem index this memory allocated from */
short int cp_kmem_index;
/* or the page size if it's not in the slab kmem array */
short int cp_kmem_size;
};
/**
* Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned
* by sub-io. Protected by a VM lock.
*/
struct cl_io *cp_owner;
/** Assigned if doing a sync_io */
struct cl_sync_io *cp_sync_io;
};
/**
* Per-layer part of cl_page.
*
* \see vvp_page, lov_page, osc_page
*/
struct cl_page_slice {
struct cl_page *cpl_page;
const struct cl_page_operations *cpl_ops;
};
/**
* Lock mode. For the client extent locks.
*
* \ingroup cl_lock
*/
enum cl_lock_mode {
CLM_READ,
CLM_WRITE,
CLM_GROUP,
CLM_MAX,
};
/**
* Requested transfer type.
*/
enum cl_req_type {
CRT_READ,
CRT_WRITE,
CRT_NR
};
/**
* Per-layer page operations.
*
* Methods taking an \a io argument are for the activity happening in the
* context of given \a io. Page is assumed to be owned by that io, except for
* the obvious cases.
*
* \see vvp_page_ops, lov_page_ops, osc_page_ops
*/
struct cl_page_operations {
/**
* cl_page<->struct page methods. Only one layer in the stack has to
* implement these. Current code assumes that this functionality is
* provided by the topmost layer, see __cl_page_disown() as an example.
*/
/**
* Update file attributes when all we have is this page. Used for tiny
* writes to update attributes when we don't have a full cl_io.
*/
void (*cpo_page_touch)(const struct lu_env *env,
const struct cl_page_slice *slice, size_t to);
/**
* Page destruction.
*/
/**
* Called when page is truncated from the object. Optional.
*
* \see cl_page_discard()
* \see vvp_page_discard(), osc_page_discard()
*/
void (*cpo_discard)(const struct lu_env *env,
const struct cl_page_slice *slice,
struct cl_io *io);
/**
* Called when page is removed from the cache, and is about to being
* destroyed. Optional.
*
* \see cl_page_delete()
* \see vvp_page_delete(), osc_page_delete()
*/
void (*cpo_delete)(const struct lu_env *env,
const struct cl_page_slice *slice);
/**
* Optional debugging helper. Prints given page slice.
*
* \see cl_page_print()
*/
int (*cpo_print)(const struct lu_env *env,
const struct cl_page_slice *slice,
void *cookie, lu_printer_t p);
/**
* \name transfer
*
* Transfer methods.
*
*/
/**
* Request type dependent vector of operations.
*
* Transfer operations depend on transfer mode (cl_req_type). To avoid
* passing transfer mode to each and every of these methods, and to
* avoid branching on request type inside of the methods, separate
* methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are
* provided. That is, method invocation usually looks like
*
* slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...);
*/
struct {
/**
* Completion handler. This is guaranteed to be eventually
* fired after cl_page_prep() or cl_page_make_ready() call.
*
* This method can be called in a non-blocking context. It is
* guaranteed however, that the page involved and its object
* are pinned in memory (and, hence, calling cl_page_put() is
* safe).
*
* \see cl_page_complete()
*/
void (*cpo_complete)(const struct lu_env *env,
const struct cl_page_slice *slice,
int ioret);
} io[CRT_NR];
/**
* Tell transfer engine that only [to, from] part of a page should be
* transmitted.
*
* This is used for immediate transfers.
*
* \todo XXX this is not very good interface. It would be much better
* if all transfer parameters were supplied as arguments to
* cl_io_operations::cio_submit() call, but it is not clear how to do
* this for page queues.
*
* \see cl_page_clip()
*/
void (*cpo_clip)(const struct lu_env *env,
const struct cl_page_slice *slice, int from, int to);
};
/**
* Helper macro, dumping detailed information about \a page into a log.
*/
#define CL_PAGE_DEBUG(mask, env, page, format, ...) \
do { \
if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
cl_page_print(env, &msgdata, lu_cdebug_printer, page); \
CDEBUG(mask, format, ## __VA_ARGS__); \
} \
} while (0)
/**
* Helper macro, dumping shorter information about \a page into a log.
*/
#define CL_PAGE_HEADER(mask, env, page, format, ...) \
do { \
if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \
CDEBUG(mask, format, ## __VA_ARGS__); \
} \
} while (0)
static inline struct page *cl_page_vmpage(const struct cl_page *page)
{
LASSERT(page->cp_vmpage != NULL);
return page->cp_vmpage;
}
static inline int cl_folio_pgno(const struct cl_page *cl_page)
{
#ifdef HAVE___FILEMAP_GET_FOLIO
struct folio *folio = page_folio(cl_page->cp_vmpage);
int pgno = folio_page_idx(folio, cl_page->cp_vmpage);
return pgno;
#else
return 0;
#endif
}
static inline void *cl_kmap_local(struct cl_page *pg)
{
return kmap_local_page(pg->cp_vmpage);
}
static inline pgoff_t cl_page_index(const struct cl_page *cp)
{
return folio_index_page(cl_page_vmpage(cp));
}
/**
* Check if a cl_page is in use.
*
* Client cache holds a refcount, this refcount will be dropped when
* the page is taken out of cache, see vvp_page_delete().
*/
static inline bool __page_in_use(const struct cl_page *page, int refc)
{
return (refcount_read(&page->cp_ref) > refc + 1);
}
/**
* Caller itself holds a refcount of cl_page.
*/
#define cl_page_in_use(pg) __page_in_use(pg, 1)
/**
* Caller doesn't hold a refcount.
*/
#define cl_page_in_use_noref(pg) __page_in_use(pg, 0)
/** \struct cl_lock
*
* Extent locking on the client.
*
* LAYERING
*
* The locking model of the new client code is built around
*
* struct cl_lock
*
* data-type representing an extent lock on a regular file. cl_lock is a
* layered object (much like cl_object and cl_page), it consists of a header
* (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to
* cl_lock::cll_layers list through cl_lock_slice::cls_linkage.
*
* Typical cl_lock consists of one layer:
*
* - lov_lock (lov specific data).
*
* lov_lock contains an array of sub-locks. Each of these sub-locks is a
* normal cl_lock: it has a header (struct cl_lock) and a list of layers:
*
* - osc_lock
*
* Each sub-lock is associated with a cl_object (representing stripe
* sub-object or the file to which top-level cl_lock is associated to), and is
* linked into that cl_object::coh_locks. In this respect cl_lock is similar to
* cl_object (that at lov layer also fans out into multiple sub-objects), and
* is different from cl_page, that doesn't fan out (there is usually exactly
* one osc_page for every vvp_page). We shall call vvp-lov portion of the lock
* a "top-lock" and its lovsub-osc portion a "sub-lock".
*
* LIFE CYCLE
*
* cl_lock is a cacheless data container for the requirements of locks to
* complete the IO. cl_lock is created before I/O starts and destroyed when the
* I/O is complete.
*
* cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached
* to cl_lock at OSC layer. LDLM lock is still cacheable.
*
* INTERFACE AND USAGE
*
* Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A
* cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue()
* methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock
* consists of multiple sub cl_locks, each sub locks will be enqueued
* correspondingly. At OSC layer, the lock enqueue request will tend to reuse
* cached LDLM lock; otherwise a new LDLM lock will have to be requested from
* OST side.
*
* cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel()
* method will be called for each layer to release the resource held by this
* lock. At OSC layer, the reference count of LDLM lock, which is held at
* clo_enqueue time, is released.
*
* LDLM lock can only be canceled if there is no cl_lock using it.
*
* Overall process of the locking during IO operation is as following:
*
* - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock()
* is called on each layer. Responsibility of this method is to add locks,
* needed by a given layer into cl_io.ci_lockset.
*
* - once locks for all layers were collected, they are sorted to avoid
* dead-locks (cl_io_locks_sort()), and enqueued.
*
* - when all locks are acquired, IO is performed;
*
* - locks are released after IO is complete.
*
* Striping introduces major additional complexity into locking. The
* fundamental problem is that it is generally unsafe to actively use (hold)
* two locks on the different OST servers at the same time, as this introduces
* inter-server dependency and can lead to cascading evictions.
*
* Basic solution is to sub-divide large read/write IOs into smaller pieces so
* that no multi-stripe locks are taken (note that this design abandons POSIX
* read/write semantics). Such pieces ideally can be executed concurrently. At
* the same time, certain types of IO cannot be sub-divived, without
* sacrificing correctness. This includes:
*
* - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee
* atomicity;
*
* - ftruncate(fd, offset), where [offset, EOF] lock has to be taken.
*
* Also, in the case of read(fd, buf, count) or write(fd, buf, count), where
* buf is a part of memory mapped Lustre file, a lock or locks protecting buf
* has to be held together with the usual lock on [offset, offset + count].
*
* Interaction with DLM
*
* In the expected setup, cl_lock is ultimately backed up by a collection of
* DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is
* implemented in osc layer, that also matches DLM events (ASTs, cancellation,
* etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed
* description of interaction with DLM.
*/
/**
* Lock description.
*/
struct cl_lock_descr {
/** Object this lock is granted for. */
struct cl_object *cld_obj;
/** Index of the first page protected by this lock. */
pgoff_t cld_start;
/** Index of the last page (inclusive) protected by this lock. */
pgoff_t cld_end;
/** Group ID, for group lock */
__u64 cld_gid;
/** Lock mode. */
enum cl_lock_mode cld_mode;
/**
* flags to enqueue lock. A combination of bit-flags from
* enum cl_enq_flags.
*/
__u32 cld_enq_flags;
};
#define DDESCR "%s(%d):[%lu, %lu]:%x"
#define PDESCR(descr) \
cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \
(descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags
const char *cl_lock_mode_name(const enum cl_lock_mode mode);
/**
* Layered client lock.
*/
struct cl_lock {
/** List of slices. Immutable after creation. */
struct list_head cll_layers;
/** lock attribute, extent, cl_object, etc. */
struct cl_lock_descr cll_descr;
};
/**
* Per-layer part of cl_lock
*
* \see lov_lock, osc_lock
*/
struct cl_lock_slice {
struct cl_lock *cls_lock;
/** Object slice corresponding to this lock slice. Immutable after
* creation.
*/
struct cl_object *cls_obj;
const struct cl_lock_operations *cls_ops;
/** Linkage into cl_lock::cll_layers. Immutable after creation. */
struct list_head cls_linkage;
};
/**
*
* \see lov_lock_ops, osc_lock_ops
*/
struct cl_lock_operations {
/**
* Attempts to enqueue the lock. Called top-to-bottom.
*
* \retval 0 this layer has enqueued the lock successfully
* \retval >0 this layer has enqueued the lock, but need to wait on
* @anchor for resources
* \retval -ve failure
*
* \see lov_lock_enqueue(), osc_lock_enqueue()
*/
int (*clo_enqueue)(const struct lu_env *env,
const struct cl_lock_slice *slice,
struct cl_io *io, struct cl_sync_io *anchor);
/**
* Cancel a lock, release its DLM lock ref, while does not cancel the
* DLM lock
*/
void (*clo_cancel)(const struct lu_env *env,
const struct cl_lock_slice *slice);
/**
* Destructor. Frees resources and the slice.
*
* \see lov_lock_fini(), osc_lock_fini()
*/
void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice);
/**
* Optional debugging helper. Prints given lock slice.
*/
int (*clo_print)(const struct lu_env *env, void *cookie,
lu_printer_t p, const struct cl_lock_slice *slice);
};
#define CL_LOCK_DEBUG(mask, env, lock, format, ...) \
do { \
if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \
LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \
cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \
CDEBUG(mask, format, ## __VA_ARGS__); \
} \
} while (0)
#define CL_LOCK_ASSERT(expr, env, lock) do { \
if (likely(expr)) \
break; \
\
CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \
LBUG(); \
} while (0)
/** \addtogroup cl_page_list cl_page_list
* Page list used to perform collective operations on a group of pages.
*
* Pages are added to the list one by one. cl_page_list acquires a reference
* for every page in it. Page list is used to perform collective operations on
* pages:
*
* - submit pages for an immediate transfer,
*
* - own pages on behalf of certain io (waiting for each page in turn),
*
* - discard pages.
*
* When list is finalized, it releases references on all pages it still has.
*
* \todo XXX concurrency control.
*
*/
struct cl_page_list {
unsigned int pl_nr;
struct list_head pl_pages;
};
/**
* A 2-queue of pages. A convenience data-type for common use case, 2-queue
* contains an incoming page list and an outgoing page list.
*/
struct cl_2queue {
struct cl_page_list c2_qin;
struct cl_page_list c2_qout;
};
/** \struct cl_io
* I/O
*
* cl_io represents a high level I/O activity like
* read(2)/write(2)/truncate(2) system call, or cancellation of an extent
* lock.
*
* cl_io is a layered object, much like cl_{object,page,lock} but with one
* important distinction. We want to minimize number of calls to the allocator
* in the fast path, e.g., in the case of read(2) when everything is cached:
* client already owns the lock over region being read, and data are cached
* due to read-ahead. To avoid allocation of cl_io layers in such situations,
* per-layer io state is stored in the session, associated with the io, see
* struct {vvp,lov,osc}_io for example. Sessions allocation is amortized
* by using free-lists, see cl_env_get().
*
* There is a small predefined number of possible io types, enumerated in enum
* cl_io_type.
*
* cl_io is a state machine, that can be advanced concurrently by the multiple
* threads. It is up to these threads to control the concurrency and,
* specifically, to detect when io is done, and its state can be safely
* released.
*
* For read/write io overall execution plan is as following:
*
* (0) initialize io state through all layers;
*
* (1) loop: prepare chunk of work to do
*
* (2) call all layers to collect locks they need to process current chunk
*
* (3) sort all locks to avoid dead-locks, and acquire them
*
* (4) process the chunk: call per-page methods
* cl_io_operations::cio_prepare_write(),
* cl_io_operations::cio_commit_write() for write)
*
* (5) release locks
*
* (6) repeat loop.
*
* To implement the "parallel IO mode", lov layer creates sub-io's (lazily to
* address allocation efficiency issues mentioned above), and returns with the
* special error condition from per-page method when current sub-io has to
* block. This causes io loop to be repeated, and lov switches to the next
* sub-io in its cl_io_operations::cio_iter_init() implementation.
*/
/** IO types */
enum cl_io_type {
/** read system call */
CIT_READ = 1,
/** write system call */
CIT_WRITE,
/** truncate, utime system calls */
CIT_SETATTR,
/** get data version */
CIT_DATA_VERSION,
/**
* page fault handling
*/
CIT_FAULT,
/**
* fsync system call handling
* To write out a range of file
*/
CIT_FSYNC,
/**
* glimpse. An io context to acquire glimpse lock.
*/
CIT_GLIMPSE,
/**
* Miscellaneous io. This is used for occasional io activity that
* doesn't fit into other types. Currently this is used for:
*
* - cancellation of an extent lock. This io exists as a context
* to write dirty pages from under the lock being canceled back
* to the server;
*
* - VM induced page write-out. An io context for writing page out
* for memory cleansing;
*
* - grouplock. An io context to acquire group lock.
*
* CIT_MISC io is used simply as a context in which locks and pages
* are manipulated. Such io has no internal "process", that is,
* cl_io_loop() is never called for it.
*/
CIT_MISC,
/**
* ladvise handling
* To give advice about access of a file
*/
CIT_LADVISE,
/**
* SEEK_HOLE/SEEK_DATA handling to search holes or data
* across all file objects
*/
CIT_LSEEK,
CIT_OP_NR
};
/**
* States of cl_io state machine
*/
enum cl_io_state {
/** Not initialized. */
CIS_ZERO,
/** Initialized. */
CIS_INIT,
/** IO iteration started. */
CIS_IT_STARTED,
/** Locks taken. */
CIS_LOCKED,
/** Actual IO is in progress. */
CIS_IO_GOING,
/** IO for the current iteration finished. */
CIS_IO_FINISHED,
/** Locks released. */
CIS_UNLOCKED,
/** Iteration completed. */
CIS_IT_ENDED,
/** cl_io finalized. */
CIS_FINI
};
/**
* IO state private for a layer.
*
* This is usually embedded into layer session data, rather than allocated
* dynamically.
*
* \see vvp_io, lov_io, osc_io
*/
struct cl_io_slice {
struct cl_io *cis_io;
/** corresponding object slice. Immutable after creation. */
struct cl_object *cis_obj;
/** io operations. Immutable after creation. */
const struct cl_io_operations *cis_iop;
/**
* linkage into a list of all slices for a given cl_io, hanging off
* cl_io::ci_layers. Immutable after creation.
*/
struct list_head cis_linkage;
};
typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *,
struct folio_batch *);
struct cl_read_ahead {
/* Maximum page index the readahead window will end.
* This is determined DLM lock coverage, RPC and stripe boundary.
* cra_end is included.
*/
pgoff_t cra_end_idx;
/* optimal RPC size for this read, by pages */
unsigned long cra_rpc_pages;
/* Release callback. If readahead holds resources underneath, this
* function should be called to release it.
*/
void (*cra_release)(const struct lu_env *env,
struct cl_read_ahead *ra);
/* Callback data for cra_release routine */
void *cra_dlmlock;
/*
* Linkage to track all cl_read_aheads for a read-ahead operations,
* used for releasing DLM locks acquired during read-ahead.
*/
struct list_head cra_linkage;
};
static inline void cl_read_ahead_release(const struct lu_env *env,
struct cl_read_ahead *ra)
{
if (ra->cra_release != NULL)
ra->cra_release(env, ra);
}
enum cl_io_priority {
/* Normal I/O, usually just queue the pages in the client side cache. */
IO_PRIO_NORMAL = 0,
/* I/O is urgent and should flush queued pages to OSTs ASAP. */
IO_PRIO_URGENT,
/* The memcg is under high memory pressure and the user write process
* is dirty exceeded and under rate limiting in balance_dirty_pages().
* It needs to flush dirty pages for the corresponding @wb ASAP.
*/
IO_PRIO_DIRTY_EXCEEDED,
/*
* I/O is urgent and flushing pages are marked with OBD_BRW_SOFT_SYNC
* flag and may trigger a soft sync on OSTs. Thus it can free unstable
* pages much quickly.
*/
IO_PRIO_SOFT_SYNC,
/*
* The system or a certain memcg is under high memory pressure. Need to
* flush dirty pages to OSTs immediately and I/O RPC must wait the write
* transcation commit on OSTs synchronously to release unstable pages.
*/
IO_PRIO_HARD_SYNC,
IO_PRIO_MAX,
};
static inline bool cl_io_high_prio(enum cl_io_priority prio)
{
return prio >= IO_PRIO_URGENT;
}
/**
* Per-layer io operations.
* \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops
*/
struct cl_io_operations {
/**
* Vector of io state transition methods for every io type.
*
* \see cl_page_operations::io
*/
struct {
/**
* Prepare io iteration at a given layer.
*
* Called top-to-bottom at the beginning of each iteration of
* "io loop" (if it makes sense for this type of io). Here
* layer selects what work it will do during this iteration.
*
* \see cl_io_operations::cio_iter_fini()
*/
int (*cio_iter_init)(const struct lu_env *env,
const struct cl_io_slice *slice);
/**
* Finalize io iteration.
*
* Called bottom-to-top at the end of each iteration of "io
* loop". Here layers can decide whether IO has to be
* continued.
*
* \see cl_io_operations::cio_iter_init()
*/
void (*cio_iter_fini)(const struct lu_env *env,
const struct cl_io_slice *slice);
/**
* Collect locks for the current iteration of io.
*
* Called top-to-bottom to collect all locks necessary for
* this iteration. This methods shouldn't actually enqueue
* anything, instead it should post a lock through
* cl_io_lock_add(). Once all locks are collected, they are
* sorted and enqueued in the proper order.
*/
int (*cio_lock)(const struct lu_env *env,
const struct cl_io_slice *slice);
/**
* Finalize unlocking.
*
* Called bottom-to-top to finish layer specific unlocking
* functionality, after generic code released all locks
* acquired by cl_io_operations::cio_lock().
*/
void (*cio_unlock)(const struct lu_env *env,
const struct cl_io_slice *slice);
/**
* Start io iteration.
*
* Once all locks are acquired, called top-to-bottom to
* commence actual IO. In the current implementation,
* top-level vvp_io_{read,write}_start() does all the work
* synchronously by calling generic_file_*(), so other layers
* are called when everything is done.
*/
int (*cio_start)(const struct lu_env *env,
const struct cl_io_slice *slice);
/**
* Called top-to-bottom at the end of io loop. Here layer
* might wait for an unfinished asynchronous io.
*/
void (*cio_end)(const struct lu_env *env,
const struct cl_io_slice *slice);
/**
* Called bottom-to-top to notify layers that read/write IO
* iteration finished, with \a nob bytes transferred.
*/
void (*cio_advance)(const struct lu_env *env,
const struct cl_io_slice *slice,
size_t nob);
/**
* Called once per io, bottom-to-top to release io resources.
*/
void (*cio_fini)(const struct lu_env *env,
const struct cl_io_slice *slice);
} op[CIT_OP_NR];
/**
* Submit pages from \a queue->c2_qin for IO, and move
* successfully submitted pages into \a queue->c2_qout. Return
* non-zero if failed to submit even the single page. If
* submission failed after some pages were moved into \a
* queue->c2_qout, completion callback with non-zero ioret is
* executed on them.
*/
int (*cio_submit)(const struct lu_env *env,
struct cl_io *io,
const struct cl_io_slice *slice,
enum cl_req_type crt, struct cl_2queue *queue);
/* the dio version of cio_submit, this either submits all pages
* successfully or fails. Uses an array, rather than a queue.
*/
int (*cio_dio_submit)(const struct lu_env *env,
struct cl_io *io,
const struct cl_io_slice *slice,
enum cl_req_type crt,
struct cl_dio_pages *cdp);
/**
* Queue async page for write.
* The difference between cio_submit and cio_queue is that
* cio_submit is for urgent request.
*/
int (*cio_commit_async)(const struct lu_env *env,
const struct cl_io_slice *slice,
struct cl_page_list *queue, int from, int to,
cl_commit_cbt cb, enum cl_io_priority prio);
/**
* Release active extent.
*/
void (*cio_extent_release)(const struct lu_env *env,
const struct cl_io_slice *slice,
enum cl_io_priority prio);
/**
* Decide maximum read ahead extent
*
* \pre io->ci_type == CIT_READ
*/
int (*cio_read_ahead_prep)(const struct lu_env *env,
const struct cl_io_slice *slice,
pgoff_t start, struct cl_read_ahead *ra);
/**
*
* Reserve LRU slots before IO.
*/
int (*cio_lru_reserve)(const struct lu_env *env,
const struct cl_io_slice *slice,
loff_t pos, size_t bytes);
/**
* Optional debugging helper. Print given io slice.
*/
int (*cio_print)(const struct lu_env *env, void *cookie,
lu_printer_t p, const struct cl_io_slice *slice);
};
/**
* Flags to lock enqueue procedure.
* \ingroup cl_lock
*/
enum cl_enq_flags {
/**
* instruct server to not block, if conflicting lock is found. Instead
* -EAGAIN is returned immediately.
*/
CEF_NONBLOCK = 0x00000001,
/**
* Tell lower layers this is a glimpse request, translated to
* LDLM_FL_HAS_INTENT at LDLM layer.
*
* Also, because glimpse locks never block other locks, we count this
* as automatically compatible with other osc locks.
* (see osc_lock_compatible)
*/
CEF_GLIMPSE = 0x00000002,
/**
* tell the server to instruct (though a flag in the blocking ast) an
* owner of the conflicting lock, that it can drop dirty pages
* protected by this lock, without sending them to the server.
*/
CEF_DISCARD_DATA = 0x00000004,
/**
* tell the sub layers that it must be a `real' lock. This is used for
* mmapped-buffer locks, glimpse locks, manually requested locks
* (LU_LADVISE_LOCKAHEAD) that must never be converted into lockless
* mode.
*
* \see vvp_mmap_locks(), cl_glimpse_lock, cl_request_lock().
*/
CEF_MUST = 0x00000008,
/**
* tell the sub layers that never request a `real' lock. This flag is
* not used currently.
*
* cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless
* conversion policy: ci_lockreq describes generic information of lock
* requirement for this IO, especially for locks which belong to the
* object doing IO; however, lock itself may have precise requirements
* that are described by the enqueue flags.
*/
CEF_NEVER = 0x00000010,
/**
* tell the dlm layer this is a speculative lock request
* speculative lock requests are locks which are not requested as part
* of an I/O operation. Instead, they are requested because we expect
* to use them in the future. They are requested asynchronously at the
* ptlrpc layer.
*
* Currently used for asynchronous glimpse locks and manually requested
* locks (LU_LADVISE_LOCKAHEAD).
*/
CEF_SPECULATIVE = 0x00000020,
/**
* enqueue a lock to test DLM lock existence.
*/
CEF_PEEK = 0x00000040,
/**
* Lock match only. Used by group lock in I/O as group lock
* is known to exist.
*/
CEF_LOCK_MATCH = 0x00000080,
/**
* tell the DLM layer to lock only the requested range
*/
CEF_LOCK_NO_EXPAND = 0x00000100,
/**
* mask of enq_flags.
*/
CEF_MASK = 0x000001ff,
};
/**
* Link between lock and io. Intermediate structure is needed, because the
* same lock can be part of multiple io's simultaneously.
*/
struct cl_io_lock_link {
/** linkage into one of cl_lockset lists. */
struct list_head cill_linkage;
struct cl_lock cill_lock;
/** optional destructor */
void (*cill_fini)(const struct lu_env *env,
struct cl_io_lock_link *link);
};
#define cill_descr cill_lock.cll_descr
/**
* Lock-set represents a collection of locks, that io needs at a
* time. Generally speaking, client tries to avoid holding multiple locks when
* possible, because
*
* - holding extent locks over multiple ost's introduces the danger of
* "cascading timeouts";
*
* - holding multiple locks over the same ost is still dead-lock prone,
* see comment in osc_lock_enqueue(),
*
* but there are certain situations where this is unavoidable:
*
* - O_APPEND writes have to take [0, EOF] lock for correctness;
*
* - truncate has to take [new-size, EOF] lock for correctness;
*
* - SNS has to take locks across full stripe for correctness;
*
* - in the case when user level buffer, supplied to {read,write}(file0),
* is a part of a memory mapped lustre file, client has to take a dlm
* locks on file0, and all files that back up the buffer (or a part of
* the buffer, that is being processed in the current chunk, in any
* case, there are situations where at least 2 locks are necessary).
*
* In such cases we at least try to take locks in the same consistent
* order. To this end, all locks are first collected, then sorted, and then
* enqueued.
*/
struct cl_lockset {
/** locks to be acquired. */
struct list_head cls_todo;
/** locks acquired. */
struct list_head cls_done;
};
/**
* Lock requirements(demand) for IO. It should be cl_io_lock_req,
* but 'req' is always to be thought as 'request' :-)
*/
enum cl_io_lock_dmd {
/** Always lock data (e.g., O_APPEND). */
CILR_MANDATORY = 0,
/** Layers are free to decide between local and global locking. */
CILR_MAYBE,
/** Never lock: there is no cache (e.g., liblustre). */
CILR_NEVER
};
enum cl_fsync_mode {
/** start writeback, do not wait for them to finish */
CL_FSYNC_NONE = 0,
/** start writeback and wait for them to finish */
CL_FSYNC_LOCAL = 1,
/** discard all of dirty pages in a specific file range */
CL_FSYNC_DISCARD = 2,
/** start writeback and make sure they have reached storage before
* return. OST_SYNC RPC must be issued and finished
*/
CL_FSYNC_ALL = 3,
/** start writeback, thus the kernel can reclaim some memory */
CL_FSYNC_RECLAIM = 4,
};
struct cl_io_rw_common {
loff_t crw_pos;
size_t crw_bytes;
int crw_nonblock;
};
enum cl_setattr_subtype {
/** regular setattr **/
CL_SETATTR_REG = 1,
/** truncate(2) **/
CL_SETATTR_TRUNC,
/** fallocate(2) - mode preallocate **/
CL_SETATTR_FALLOCATE
};
struct cl_io_range {
loff_t cir_pos;
size_t cir_count;
};
struct cl_io_pt {
struct cl_io_pt *cip_next;
struct kiocb cip_iocb;
struct iov_iter cip_iter;
struct file *cip_file;
enum cl_io_type cip_iot;
unsigned int cip_need_restart:1;
loff_t cip_pos;
size_t cip_count;
ssize_t cip_result;
};
/**
* State for io.
*
* cl_io is shared by all threads participating in this IO (in current
* implementation only one thread advances IO, but parallel IO design and
* concurrent copy_*_user() require multiple threads acting on the same IO. It
* is up to these threads to serialize their activities, including updates to
* mutable cl_io fields.
*/
struct cl_io {
/** type of this IO. Immutable after creation. */
enum cl_io_type ci_type;
/** current state of cl_io state machine. */
enum cl_io_state ci_state;
/** main object this io is against. Immutable after creation. */
struct cl_object *ci_obj;
/** top level dio_aio */
struct cl_dio_aio *ci_dio_aio;
/**
* Upper layer io, of which this io is a part of. Immutable after
* creation.
*/
struct cl_io *ci_parent;
/** List of slices. Immutable after creation. */
struct list_head ci_layers;
/** list of locks (to be) acquired by this io. */
struct cl_lockset ci_lockset;
/** lock requirements, this is just a help info for sublayers. */
enum cl_io_lock_dmd ci_lockreq;
/** layout version when this IO occurs */
__u32 ci_layout_version;
union {
struct cl_rd_io {
struct cl_io_rw_common rd;
} ci_rd;
struct cl_wr_io {
struct cl_io_rw_common wr;
loff_t wr_append_lockpos;
int wr_append;
int wr_sync;
} ci_wr;
struct cl_io_rw_common ci_rw;
struct cl_setattr_io {
struct ost_lvb sa_attr;
unsigned int sa_attr_flags;
unsigned int sa_avalid; /* ATTR_* */
unsigned int sa_xvalid; /* OP_XVALID */
int sa_stripe_index;
struct ost_layout sa_layout;
const struct lu_fid *sa_parent_fid;
/* SETATTR interface is used for regular setattr, */
/* truncate(2) and fallocate(2) subtypes */
enum cl_setattr_subtype sa_subtype;
/* The following are used for fallocate(2) */
int sa_falloc_mode;
loff_t sa_falloc_offset;
loff_t sa_falloc_end;
/* id fields used for truncate/fallocate */
uid_t sa_attr_uid;
gid_t sa_attr_gid;
__u32 sa_attr_projid;
} ci_setattr;
struct cl_data_version_io {
u64 dv_data_version;
u32 dv_layout_version;
int dv_flags;
} ci_data_version;
struct cl_fault_io {
/** page index within file. */
pgoff_t ft_index;
/** bytes valid byte on a faulted page. */
size_t ft_bytes;
/** writable page? for nopage() only */
int ft_writable;
/** page of an executable? */
int ft_executable;
/** page_mkwrite() */
int ft_mkwrite;
/** resulting page */
struct cl_page *ft_page;
} ci_fault;
struct cl_fsync_io {
loff_t fi_start;
loff_t fi_end;
/** file system level fid */
struct lu_fid *fi_fid;
enum cl_fsync_mode fi_mode;
/* how many pages were written/discarded */
unsigned int fi_nr_written;
enum cl_io_priority fi_prio;
} ci_fsync;
struct cl_ladvise_io {
__u64 lio_start;
__u64 lio_end;
/** file system level fid */
struct lu_fid *lio_fid;
enum lu_ladvise_type lio_advice;
__u64 lio_flags;
} ci_ladvise;
struct cl_lseek_io {
loff_t ls_start;
loff_t ls_result;
int ls_whence;
} ci_lseek;
struct cl_misc_io {
time64_t lm_next_rpc_time;
} ci_misc;
} u;
struct cl_2queue ci_queue;
size_t ci_bytes;
int ci_result;
unsigned int ci_continue:1,
/**
* This io has held grouplock, to inform sublayers that
* don't do lockless i/o.
*/
ci_no_srvlock:1,
/**
* The whole IO need to be restarted because layout has been changed
*/
ci_need_restart:1,
/**
* to not refresh layout - the IO issuer knows that the layout won't
* change(page operations, layout change causes all page to be
* discarded), or it doesn't matter if it changes(sync).
*/
ci_ignore_layout:1,
/**
* Need MDS intervention to complete a write.
* Write intent is required for the following cases:
* 1. component being written is not initialized, or
* 2. the mirrored files are NOT in WRITE_PENDING state.
*/
ci_need_write_intent:1,
/**
* File is in PCC-RO state, need MDS intervention to complete
* a data modifying operation.
*/
ci_need_pccro_clear:1,
/**
* Check if layout changed after the IO finishes. Mainly for HSM
* requirement. If IO occurs to openning files, it doesn't need to
* verify layout because HSM won't release openning files.
* Right now, only two opertaions need to verify layout: glimpse
* and setattr.
*/
ci_verify_layout:1,
/**
* file is released, restore has to to be triggered by vvp layer
*/
ci_restore_needed:1,
/**
* O_NOATIME
*/
ci_noatime:1,
/* Tell sublayers not to expand LDLM locks requested for this IO */
ci_lock_no_expand:1,
/**
* Set if non-delay RPC should be used for this IO.
*
* If this file has multiple mirrors, and if the OSTs of the current
* mirror is inaccessible, non-delay RPC would error out quickly so
* that the upper layer can try to access the next mirror.
*/
ci_ndelay:1,
/**
* Set if IO is triggered by async workqueue readahead.
*/
ci_async_readahead:1,
/**
* Ignore lockless and do normal locking for this io.
*/
ci_dio_lock:1,
/**
* Set if we've tried all mirrors for this read IO, if it's not set,
* the read IO will check to-be-read OSCs' status, and make fast-switch
* another mirror if some of the OSTs are not healthy.
*/
ci_tried_all_mirrors:1,
/**
* Random read hints, readahead will be disabled.
*/
ci_rand_read:1,
/**
* Sequential read hints.
*/
ci_seq_read:1,
/**
* Do parallel (async) submission of DIO RPCs. Note DIO is still sync
* to userspace, only the RPCs are submitted async, then waited for at
* the llite layer before returning.
*/
ci_parallel_dio:1,
/**
* this DIO is at least partly unaligned, and so the unaligned DIO
* path is being used for this entire IO
*/
ci_unaligned_dio:1,
/**
* there is an interop issue with unpatched clients/servers that
* exceed 4k read/write offsets with I/O exceeding LNET_MTU.
* This flag cleared if a target is not patched.
*/
ci_allow_unaligned_dio:1,
/**
* Bypass quota check
*/
ci_noquota:1,
/**
* io_uring direct IO with flags IOCB_NOWAIT.
*/
ci_iocb_nowait:1,
/**
* The filesystem must exclusively acquire invalidate_lock before
* invalidating page cache in truncate / hole punch / DLM extent
* lock blocking AST path (and thus calling into ->invalidatepage)
* to block races between page cache invalidation and page cache
* filling functions (fault, read, ...)
*/
ci_invalidate_page_cache:1,
/* was this IO switched from BIO to DIO for hybrid IO? */
ci_hybrid_switched:1;
/**
* How many times the read has retried before this one.
* Set by the top level and consumed by the LOV.
*/
unsigned int ci_ndelay_tried;
/**
* Designated mirror index for this I/O.
*/
unsigned int ci_designated_mirror;
/**
* Number of pages owned by this IO. For invariant checking.
*/
unsigned int ci_owned_nr;
/**
* Range of write intent. Valid if ci_need_write_intent is set.
*/
struct lu_extent ci_write_intent;
};
/**
* Per-transfer attributes.
*/
struct cl_req_attr {
enum cl_req_type cra_type;
u64 cra_flags;
struct cl_page *cra_page;
/** Generic attributes for the server consumption. */
struct obdo *cra_oa;
/** process jobid/uid/gid performing the io */
struct job_info cra_jobinfo;
};
enum cache_stats_item {
/** how many cache lookups were performed */
CS_lookup = 0,
/** how many times cache lookup resulted in a hit */
CS_hit,
/** how many entities are in the cache right now */
CS_total,
/** how many entities in the cache are actively used (and cannot be
* evicted) right now
*/
CS_busy,
/** how many entities were created at all */
CS_create,
CS_NR
};
#define CS_NAMES { "lookup", "hit", "total", "busy", "create" }
/**
* Stats for a generic cache (similar to inode, lu_object, etc. caches).
*/
struct cache_stats {
const char *cs_name;
atomic_t cs_stats[CS_NR];
};
/** These are not exported so far */
void cache_stats_init(struct cache_stats *cs, const char *name);
/**
* Client-side site. This represents particular client stack. "Global"
* variables should (directly or indirectly) be added here to allow multiple
* clients to co-exist in the single address space.
*/
struct cl_site {
struct lu_site cs_lu;
/**
* Statistical counters. Atomics do not scale, something better like
* per-cpu counters is needed.
*
* These are exported as /proc/fs/lustre/llite/.../site
*
* When interpreting keep in mind that both sub-locks (and sub-pages)
* and top-locks (and top-pages) are accounted here.
*/
struct cache_stats cs_pages;
atomic_t cs_pages_state[CPS_NR];
};
int cl_site_init(struct cl_site *s, struct cl_device *top);
void cl_site_fini(struct cl_site *s);
/**
* Output client site statistical counters into a buffer. Suitable for
* ll_rd_*()-style functions.
*/
int cl_site_stats_print(const struct cl_site *site, struct seq_file *m);
/**
* \name helpers
*
* Type conversion and accessory functions.
*/
static inline struct cl_site *lu2cl_site(const struct lu_site *site)
{
return container_of(site, struct cl_site, cs_lu);
}
static inline struct cl_device *lu2cl_dev(const struct lu_device *d)
{
LASSERT(d == NULL || IS_ERR(d) || lu_device_is_cl(d));
return container_of_safe(d, struct cl_device, cd_lu_dev);
}
static inline struct lu_device *cl2lu_dev(struct cl_device *d)
{
return &d->cd_lu_dev;
}
static inline struct cl_object *lu2cl(const struct lu_object *o)
{
LASSERT(o == NULL || IS_ERR(o) || lu_device_is_cl(o->lo_dev));
return container_of_safe(o, struct cl_object, co_lu);
}
static inline const struct cl_object_conf *
lu2cl_conf(const struct lu_object_conf *conf)
{
return container_of_safe(conf, struct cl_object_conf, coc_lu);
}
static inline struct cl_object_header *luh2coh(const struct lu_object_header *h)
{
return container_of_safe(h, struct cl_object_header, coh_lu);
}
static inline struct cl_site *cl_object_site(const struct cl_object *obj)
{
return lu2cl_site(obj->co_lu.lo_dev->ld_site);
}
static inline
struct cl_object_header *cl_object_header(const struct cl_object *obj)
{
return luh2coh(obj->co_lu.lo_header);
}
static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t)
{
return lu_device_init(&d->cd_lu_dev, t);
}
static inline void cl_device_fini(struct cl_device *d)
{
lu_device_fini(&d->cd_lu_dev);
}
void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
struct cl_object *obj,
const struct cl_page_operations *ops);
void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
struct cl_object *obj,
const struct cl_lock_operations *ops);
void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice,
struct cl_object *obj, const struct cl_io_operations *ops);
struct cl_object *cl_object_top(struct cl_object *o);
struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd,
const struct lu_fid *fid,
const struct cl_object_conf *c);
int cl_object_header_init(struct cl_object_header *h);
void cl_object_header_fini(struct cl_object_header *h);
void cl_object_put(const struct lu_env *env, struct cl_object *o);
void cl_object_get(struct cl_object *o);
void cl_object_attr_lock(struct cl_object *o);
void cl_object_attr_unlock(struct cl_object *o);
int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj,
struct cl_attr *attr);
int cl_object_attr_update(const struct lu_env *env, struct cl_object *obj,
const struct cl_attr *attr,
enum cl_attr_valid valid);
void cl_object_dirty_for_sync(const struct lu_env *env, struct cl_object *obj);
int cl_object_glimpse(const struct lu_env *env, struct cl_object *obj,
struct ost_lvb *lvb);
int cl_conf_set(const struct lu_env *env, struct cl_object *obj,
const struct cl_object_conf *conf);
int cl_object_prune(const struct lu_env *env, struct cl_object *obj);
void cl_object_kill(const struct lu_env *env, struct cl_object *obj);
int cl_object_getstripe(const struct lu_env *env, struct cl_object *obj,
struct lov_user_md __user *lum, size_t size);
int cl_object_fiemap(const struct lu_env *env, struct cl_object *obj,
struct ll_fiemap_info_key *fmkey, struct fiemap *fiemap,
size_t *buflen);
int cl_object_layout_get(const struct lu_env *env, struct cl_object *obj,
struct cl_layout *cl);
loff_t cl_object_maxbytes(struct cl_object *obj);
int cl_object_flush(const struct lu_env *env, struct cl_object *obj,
struct ldlm_lock *lock);
void cl_req_projid_set(const struct lu_env *env, struct cl_object *obj,
__u32 *projid);
/**
* Returns true, iff \a o0 and \a o1 are slices of the same object.
*/
static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1)
{
return cl_object_header(o0) == cl_object_header(o1);
}
static inline void cl_object_page_init(struct cl_object *clob, int size)
{
clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize;
cl_object_header(clob)->coh_page_bufsize += round_up(size, 8);
WARN_ON(cl_object_header(clob)->coh_page_bufsize > 512);
}
static inline void *cl_object_page_slice(struct cl_object *clob,
struct cl_page *page)
{
return (void *)((char *)page + clob->co_slice_off);
}
/**
* Return refcount of cl_object.
*/
static inline int cl_object_refc(struct cl_object *clob)
{
struct lu_object_header *header = clob->co_lu.lo_header;
return atomic_read(&header->loh_ref);
}
ssize_t cl_dio_pages_init(const struct lu_env *env, struct cl_object *obj,
struct cl_dio_pages *cdp, struct iov_iter *iter,
int rw, size_t maxsize, loff_t offset,
bool unaligned);
/* cl_page */
struct cl_page *cl_page_find(const struct lu_env *env,
struct cl_object *obj,
pgoff_t idx, struct page *vmpage,
enum cl_page_type type);
struct cl_page *cl_page_alloc(const struct lu_env *env,
struct cl_object *o, pgoff_t ind,
struct page *vmpage,
enum cl_page_type type);
void cl_page_get(struct cl_page *page);
void cl_page_put(const struct lu_env *env,
struct cl_page *page);
void cl_batch_put(const struct lu_env *env, struct cl_page *page,
struct folio_batch *fbatch);
void cl_page_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_page *pg);
void cl_page_header_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_page *pg);
struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj);
static inline struct cl_page *cl_page_from_folio(struct page *vmpage,
pgoff_t index, bool get)
{
return cl_vmpage_page(vmpage, NULL);
}
/**
* \name ownership
*
* Functions dealing with the ownership of page by io.
*/
int cl_page_own(const struct lu_env *env, struct cl_io *io,
struct cl_page *page);
int cl_page_own_try(const struct lu_env *env,
struct cl_io *io, struct cl_page *page);
void cl_page_assume(const struct lu_env *env,
struct cl_io *io, struct cl_page *page);
void cl_page_unassume(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg);
void cl_page_disown(const struct lu_env *env, struct cl_io *io,
struct cl_page *page);
int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io);
/**
* \name transfer
*
* Functions dealing with the preparation of a page for a transfer, and
* tracking transfer state.
*/
int cl_page_prep(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg, enum cl_req_type crt);
void cl_dio_pages_complete(const struct lu_env *env, struct cl_dio_pages *pg,
int count, int ioret);
void cl_page_complete(const struct lu_env *env, struct cl_page *pg,
enum cl_req_type crt, int ioret);
int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
enum cl_req_type crt);
void cl_page_clip(const struct lu_env *env, struct cl_page *pg, int from,
int to);
/**
* \name helper routines
* Functions to discard, delete and export a cl_page.
*/
void cl_page_discard(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg);
void cl_page_delete(const struct lu_env *env, struct cl_page *pg);
void cl_page_touch(const struct lu_env *env, const struct cl_page *pg,
size_t to);
void cl_lock_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_lock *lock);
void cl_lock_descr_print(const struct lu_env *env, void *cookie,
lu_printer_t printer,
const struct cl_lock_descr *descr);
/**
* Data structure managing a client's cached pages. A count of
* "unstable" pages is maintained, and an LRU of clean pages is
* maintained. "unstable" pages are pages pinned by the ptlrpc
* layer for recovery purposes.
*/
struct cl_client_cache {
/**
* # of client cache refcount
* # of users (OSCs) + 2 (held by llite and lov)
*/
refcount_t ccc_users;
/**
* # of threads are doing shrinking
*/
unsigned int ccc_lru_shrinkers;
/**
* # of LRU entries available
*/
atomic_long_t ccc_lru_left;
/**
* # of unevictable LRU entries
*/
atomic_long_t ccc_unevict_lru_used;
/**
* List of entities(OSCs) for this LRU cache
*/
struct list_head ccc_lru;
/**
* Max # of LRU entries
*/
unsigned long ccc_lru_max;
/**
* Lock to protect ccc_lru list
*/
spinlock_t ccc_lru_lock;
/**
* Set if unstable check is enabled
*/
unsigned int ccc_unstable_check:1,
/**
* Whether unevictable (mlock pages) checking is enabled
*/
ccc_mlock_pages_enable:1;
/**
* # of unstable pages for this mount point
*/
atomic_long_t ccc_unstable_nr;
/**
* Serialize max_cache_mb write operation
*/
struct mutex ccc_max_cache_mb_lock;
};
/**
* cl_cache functions
*/
struct cl_client_cache *cl_cache_init(unsigned long lru_page_max);
void cl_cache_incref(struct cl_client_cache *cache);
void cl_cache_decref(struct cl_client_cache *cache);
/* cl_lock */
int cl_lock_request(const struct lu_env *env, struct cl_io *io,
struct cl_lock *lock);
int cl_lock_init(const struct lu_env *env, struct cl_lock *lock,
const struct cl_io *io);
void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock);
const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
const struct lu_device_type *dtype);
void cl_lock_release(const struct lu_env *env, struct cl_lock *lock);
int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io,
struct cl_lock *lock, struct cl_sync_io *anchor);
void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock);
struct cl_dio_pages;
/* cl_io */
int cl_io_init(const struct lu_env *env, struct cl_io *io,
enum cl_io_type iot, struct cl_object *obj);
int cl_io_sub_init(const struct lu_env *env, struct cl_io *io,
enum cl_io_type iot, struct cl_object *obj);
int cl_io_rw_init(const struct lu_env *env, struct cl_io *io,
enum cl_io_type iot, loff_t pos, size_t bytes);
int cl_io_loop(const struct lu_env *env, struct cl_io *io);
void cl_io_fini(const struct lu_env *env, struct cl_io *io);
int cl_io_iter_init(const struct lu_env *env, struct cl_io *io);
void cl_io_iter_fini(const struct lu_env *env, struct cl_io *io);
int cl_io_lock(const struct lu_env *env, struct cl_io *io);
void cl_io_unlock(const struct lu_env *env, struct cl_io *io);
int cl_io_start(const struct lu_env *env, struct cl_io *io);
void cl_io_end(const struct lu_env *env, struct cl_io *io);
int cl_io_lock_add(const struct lu_env *env, struct cl_io *io,
struct cl_io_lock_link *link);
int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io,
struct cl_lock_descr *descr);
int cl_dio_submit_rw (const struct lu_env *env, struct cl_io *io,
enum cl_req_type iot, struct cl_dio_pages *cdp);
int cl_io_submit_rw(const struct lu_env *env, struct cl_io *io,
enum cl_req_type iot, struct cl_2queue *queue);
int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io,
enum cl_req_type iot, struct cl_2queue *queue,
long timeout);
int cl_io_commit_async(const struct lu_env *env, struct cl_io *io,
struct cl_page_list *queue, int from, int to,
cl_commit_cbt cb, enum cl_io_priority prio);
void cl_io_extent_release(const struct lu_env *env, struct cl_io *io,
enum cl_io_priority prio);
int cl_io_lru_reserve(const struct lu_env *env, struct cl_io *io,
loff_t pos, size_t bytes);
int cl_io_read_ahead_prep(const struct lu_env *env, struct cl_io *io,
pgoff_t start, struct cl_read_ahead *ra);
void cl_io_rw_advance(const struct lu_env *env, struct cl_io *io,
size_t bytes);
/**
* True, iff \a io is an O_APPEND write(2).
*/
static inline int cl_io_is_append(const struct cl_io *io)
{
return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append;
}
static inline int cl_io_is_sync_write(const struct cl_io *io)
{
return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync;
}
static inline int cl_io_is_mkwrite(const struct cl_io *io)
{
return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
}
/**
* True, iff \a io is a truncate(2).
*/
static inline int cl_io_is_trunc(const struct cl_io *io)
{
return io->ci_type == CIT_SETATTR &&
(io->u.ci_setattr.sa_avalid & ATTR_SIZE) &&
(io->u.ci_setattr.sa_subtype != CL_SETATTR_FALLOCATE);
}
static inline int cl_io_is_fallocate(const struct cl_io *io)
{
return (io->ci_type == CIT_SETATTR) &&
(io->u.ci_setattr.sa_subtype == CL_SETATTR_FALLOCATE);
}
struct cl_io *cl_io_top(struct cl_io *io);
#define CL_IO_SLICE_CLEAN(obj, base) memset_startat(obj, 0, base)
/* cl_page_list */
/**
* Last page in the page list.
*/
static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist)
{
LASSERT(plist->pl_nr > 0);
return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch);
}
static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist)
{
LASSERT(plist->pl_nr > 0);
return list_first_entry(&plist->pl_pages, struct cl_page, cp_batch);
}
/**
* Iterate over pages in a page list.
*/
#define cl_page_list_for_each(page, list) \
list_for_each_entry((page), &(list)->pl_pages, cp_batch)
/**
* Iterate over pages in a page list, taking possible removals into account.
*/
#define cl_page_list_for_each_safe(page, temp, list) \
list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch)
void cl_page_list_init(struct cl_page_list *plist);
void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page,
bool getref);
void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src,
struct cl_page *page);
void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src,
struct cl_page *page);
void cl_page_list_splice(struct cl_page_list *list,
struct cl_page_list *head);
void cl_page_list_del(const struct lu_env *env,
struct cl_page_list *plist, struct cl_page *page,
bool putref);
void cl_page_list_disown(const struct lu_env *env,
struct cl_page_list *plist);
void cl_page_list_assume(const struct lu_env *env,
struct cl_io *io, struct cl_page_list *plist);
void cl_page_list_discard(const struct lu_env *env,
struct cl_io *io, struct cl_page_list *plist);
void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist);
void cl_2queue_init(struct cl_2queue *queue);
void cl_2queue_disown(const struct lu_env *env, struct cl_2queue *queue);
void cl_2queue_assume(const struct lu_env *env, struct cl_io *io,
struct cl_2queue *queue);
void cl_2queue_discard(const struct lu_env *env, struct cl_io *io,
struct cl_2queue *queue);
void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue);
void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page);
void cl_req_attr_set(const struct lu_env *env, struct cl_object *obj,
struct cl_req_attr *attr);
/* cl_sync_io */
struct cl_sync_io;
struct cl_dio_aio;
struct cl_sub_dio;
typedef void (cl_sync_io_end_t)(const struct lu_env *, struct cl_sync_io *);
void cl_sync_io_init_notify(struct cl_sync_io *anchor, int nr, void *dio_aio,
cl_sync_io_end_t *end);
int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor,
long timeout);
void __cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
int count, int ioret);
void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor,
int ioret);
int cl_sync_io_wait_recycle(const struct lu_env *env, struct cl_sync_io *anchor,
long timeout, int ioret);
struct cl_dio_aio *cl_dio_aio_alloc(struct kiocb *iocb, struct cl_object *obj,
bool is_aio);
struct cl_sub_dio *cl_sub_dio_alloc(struct cl_dio_aio *ll_aio,
struct iov_iter *iter, bool write,
bool unaligned, bool sync);
void cl_dio_aio_free(const struct lu_env *env, struct cl_dio_aio *aio);
void cl_sub_dio_free(struct cl_sub_dio *sdio);
static inline void cl_sync_io_init(struct cl_sync_io *anchor, int nr)
{
cl_sync_io_init_notify(anchor, nr, NULL, NULL);
}
/**
* Anchor for synchronous transfer. This is allocated on a stack by thread
* doing synchronous transfer, and a pointer to this structure is set up in
* every page submitted for transfer. Transfer completion routine updates
* anchor and wakes up waiting thread when transfer is complete.
*/
struct cl_sync_io {
/** number of pages yet to be transferred. */
atomic_t csi_sync_nr;
/** has this i/o completed? */
atomic_t csi_complete;
/** error code. */
int csi_sync_rc;
/** completion to be signaled when transfer is complete. */
wait_queue_head_t csi_waitq;
/** callback to invoke when this IO is finished */
cl_sync_io_end_t *csi_end_io;
/* private pointer for an associated DIO/AIO */
void *csi_dio_aio;
};
/** direct IO pages */
struct cl_dio_pages {
/*
* page array for RDMA - for aligned i/o, this is the user provided
* pages, but for unaligned i/o, this is the internal buffer
*/
struct page **cdp_pages;
struct cl_page **cdp_cl_pages;
struct cl_sync_io *cdp_sync_io;
/* the file offset of the first page. */
loff_t cdp_file_offset;
unsigned int cdp_lov_index;
loff_t cdp_osc_off;
/** # of pages in the array. */
unsigned int cdp_page_count;
/* the first and last page can be incomplete, this records the
* offsets
*/
int cdp_from;
int cdp_to;
};
/* Top level struct used for AIO and DIO */
struct cl_dio_aio {
struct cl_sync_io cda_sync;
struct cl_object *cda_obj;
struct kiocb *cda_iocb;
ssize_t cda_bytes;
struct mm_struct *cda_mm;
unsigned cda_no_aio_complete:1,
cda_creator_free:1,
cda_is_aio:1;
};
struct cl_iter_dup {
void *id_vec; /* dup'd vec (iov/bvec/kvec) */
size_t id_vec_size; /* bytes allocated for id_vec */
};
/* Sub-dio used for splitting DIO (and AIO, because AIO is DIO) according to
* the layout/striping, so we can do parallel submit of DIO RPCs
*/
struct cl_sub_dio {
struct cl_sync_io csd_sync;
ssize_t csd_bytes;
struct cl_dio_aio *csd_ll_aio;
struct cl_dio_pages csd_dio_pages;
struct iov_iter csd_iter;
struct cl_iter_dup csd_dup;
wait_queue_head_t csd_write_waitq;
spinlock_t csd_write_lock;
ssize_t csd_write_status;
unsigned csd_creator_free:1,
csd_write:1,
csd_unaligned:1,
csd_write_copying:1,
csd_write_copied:1;
};
void ll_release_user_pages(struct page **pages, int npages);
int ll_allocate_dio_buffer(struct cl_dio_pages *cdp, size_t io_size);
void ll_free_dio_buffer(struct cl_dio_pages *cdp);
ssize_t ll_dio_user_copy(struct cl_sub_dio *sdio);
#ifndef HAVE_KTHREAD_USE_MM
#define kthread_use_mm(mm) use_mm(mm)
#define kthread_unuse_mm(mm) unuse_mm(mm)
#endif
/** \defgroup cl_env cl_env
*
* lu_env handling for a client.
*
* lu_env is an environment within which lustre code executes. Its major part
* is lu_context---a fast memory allocation mechanism that is used to conserve
* precious kernel stack space. Originally lu_env was designed for a server,
* where
*
* - there is a (mostly) fixed number of threads, and
*
* - call chains have no non-lustre portions inserted between lustre code.
*
* On a client both these assumtpion fails, because every user thread can
* potentially execute lustre code as part of a system call, and lustre calls
* into VFS or MM that call back into lustre.
*
* To deal with that, cl_env wrapper functions implement the following
* optimizations:
*
* - allocation and destruction of environment is amortized by caching no
* longer used environments instead of destroying them;
*
* \see lu_env, lu_context, lu_context_key
*/
/* cl_env */
struct lu_env *cl_env_get(__u16 *refcheck);
struct lu_env *cl_env_alloc(__u16 *refcheck, __u32 tags);
void cl_env_put(struct lu_env *env, __u16 *refcheck);
unsigned int cl_env_cache_purge(unsigned int nr);
struct lu_env *cl_env_percpu_get(void);
void cl_env_percpu_put(struct lu_env *env);
/*
* Misc
*/
void cl_attr2lvb(struct ost_lvb *lvb, const struct cl_attr *attr);
void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb);
struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site,
struct lu_device_type *ldt,
struct lu_device *next);
int cl_global_init(void);
void cl_global_fini(void);
int lov_read_and_clear_async_rc(struct cl_object *clob);
#endif /* _LINUX_CL_OBJECT_H */
