Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1 | /* |
| 2 | * GPL HEADER START |
| 3 | * |
| 4 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 only, |
| 8 | * as published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, but |
| 11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * General Public License version 2 for more details (a copy is included |
| 14 | * in the LICENSE file that accompanied this code). |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * version 2 along with this program; If not, see |
| 18 | * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf |
| 19 | * |
| 20 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 21 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 22 | * have any questions. |
| 23 | * |
| 24 | * GPL HEADER END |
| 25 | */ |
| 26 | /* |
| 27 | * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. |
| 28 | * Use is subject to license terms. |
| 29 | * |
Andreas Dilger | 1dc563a | 2015-11-08 18:09:37 -0500 | [diff] [blame] | 30 | * Copyright (c) 2011, 2015, Intel Corporation. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 31 | */ |
| 32 | /* |
| 33 | * This file is part of Lustre, http://www.lustre.org/ |
| 34 | * Lustre is a trademark of Sun Microsystems, Inc. |
| 35 | */ |
| 36 | #ifndef _LUSTRE_CL_OBJECT_H |
| 37 | #define _LUSTRE_CL_OBJECT_H |
| 38 | |
| 39 | /** \defgroup clio clio |
| 40 | * |
| 41 | * Client objects implement io operations and cache pages. |
| 42 | * |
| 43 | * Examples: lov and osc are implementations of cl interface. |
| 44 | * |
| 45 | * Big Theory Statement. |
| 46 | * |
| 47 | * Layered objects. |
| 48 | * |
| 49 | * Client implementation is based on the following data-types: |
| 50 | * |
| 51 | * - cl_object |
| 52 | * |
| 53 | * - cl_page |
| 54 | * |
| 55 | * - cl_lock represents an extent lock on an object. |
| 56 | * |
| 57 | * - cl_io represents high-level i/o activity such as whole read/write |
| 58 | * system call, or write-out of pages from under the lock being |
| 59 | * canceled. cl_io has sub-ios that can be stopped and resumed |
| 60 | * independently, thus achieving high degree of transfer |
| 61 | * parallelism. Single cl_io can be advanced forward by |
| 62 | * the multiple threads (although in the most usual case of |
| 63 | * read/write system call it is associated with the single user |
| 64 | * thread, that issued the system call). |
| 65 | * |
| 66 | * - cl_req represents a collection of pages for a transfer. cl_req is |
| 67 | * constructed by req-forming engine that tries to saturate |
| 68 | * transport with large and continuous transfers. |
| 69 | * |
| 70 | * Terminology |
| 71 | * |
| 72 | * - to avoid confusion high-level I/O operation like read or write system |
| 73 | * call is referred to as "an io", whereas low-level I/O operation, like |
| 74 | * RPC, is referred to as "a transfer" |
| 75 | * |
| 76 | * - "generic code" means generic (not file system specific) code in the |
| 77 | * hosting environment. "cl-code" means code (mostly in cl_*.c files) that |
| 78 | * is not layer specific. |
| 79 | * |
| 80 | * Locking. |
| 81 | * |
| 82 | * - i_mutex |
| 83 | * - PG_locked |
| 84 | * - cl_object_header::coh_page_guard |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 85 | * - lu_site::ls_guard |
| 86 | * |
| 87 | * See the top comment in cl_object.c for the description of overall locking and |
| 88 | * reference-counting design. |
| 89 | * |
| 90 | * See comments below for the description of i/o, page, and dlm-locking |
| 91 | * design. |
| 92 | * |
| 93 | * @{ |
| 94 | */ |
| 95 | |
| 96 | /* |
| 97 | * super-class definitions. |
| 98 | */ |
Greg Kroah-Hartman | 1accaad | 2014-07-11 21:34:24 -0700 | [diff] [blame] | 99 | #include "lu_object.h" |
John L. Hammond | 0d34565 | 2016-03-30 19:48:45 -0400 | [diff] [blame] | 100 | #include <linux/atomic.h> |
John L. Hammond | 91b3aaf | 2014-09-09 13:39:08 -0500 | [diff] [blame] | 101 | #include "linux/lustre_compat25.h" |
Greg Kroah-Hartman | 1accaad | 2014-07-11 21:34:24 -0700 | [diff] [blame] | 102 | #include <linux/mutex.h> |
| 103 | #include <linux/radix-tree.h> |
John L. Hammond | 0d34565 | 2016-03-30 19:48:45 -0400 | [diff] [blame] | 104 | #include <linux/spinlock.h> |
| 105 | #include <linux/wait.h> |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 106 | |
| 107 | struct inode; |
| 108 | |
| 109 | struct cl_device; |
| 110 | struct cl_device_operations; |
| 111 | |
| 112 | struct cl_object; |
| 113 | struct cl_object_page_operations; |
| 114 | struct cl_object_lock_operations; |
| 115 | |
| 116 | struct cl_page; |
| 117 | struct cl_page_slice; |
| 118 | struct cl_lock; |
| 119 | struct cl_lock_slice; |
| 120 | |
| 121 | struct cl_lock_operations; |
| 122 | struct cl_page_operations; |
| 123 | |
| 124 | struct cl_io; |
| 125 | struct cl_io_slice; |
| 126 | |
| 127 | struct cl_req; |
| 128 | struct cl_req_slice; |
| 129 | |
| 130 | /** |
| 131 | * Operations for each data device in the client stack. |
| 132 | * |
| 133 | * \see vvp_cl_ops, lov_cl_ops, lovsub_cl_ops, osc_cl_ops |
| 134 | */ |
| 135 | struct cl_device_operations { |
| 136 | /** |
| 137 | * Initialize cl_req. This method is called top-to-bottom on all |
| 138 | * devices in the stack to get them a chance to allocate layer-private |
| 139 | * data, and to attach them to the cl_req by calling |
| 140 | * cl_req_slice_add(). |
| 141 | * |
| 142 | * \see osc_req_init(), lov_req_init(), lovsub_req_init() |
John L. Hammond | 103b8bd | 2016-03-30 19:48:54 -0400 | [diff] [blame] | 143 | * \see vvp_req_init() |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 144 | */ |
| 145 | int (*cdo_req_init)(const struct lu_env *env, struct cl_device *dev, |
| 146 | struct cl_req *req); |
| 147 | }; |
| 148 | |
| 149 | /** |
| 150 | * Device in the client stack. |
| 151 | * |
John L. Hammond | 3c95b83 | 2016-03-30 19:48:46 -0400 | [diff] [blame] | 152 | * \see vvp_device, lov_device, lovsub_device, osc_device |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 153 | */ |
| 154 | struct cl_device { |
| 155 | /** Super-class. */ |
| 156 | struct lu_device cd_lu_dev; |
| 157 | /** Per-layer operation vector. */ |
| 158 | const struct cl_device_operations *cd_ops; |
| 159 | }; |
| 160 | |
| 161 | /** \addtogroup cl_object cl_object |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 162 | * @{ |
| 163 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 164 | /** |
| 165 | * "Data attributes" of cl_object. Data attributes can be updated |
| 166 | * independently for a sub-object, and top-object's attributes are calculated |
| 167 | * from sub-objects' ones. |
| 168 | */ |
| 169 | struct cl_attr { |
| 170 | /** Object size, in bytes */ |
| 171 | loff_t cat_size; |
| 172 | /** |
| 173 | * Known minimal size, in bytes. |
| 174 | * |
| 175 | * This is only valid when at least one DLM lock is held. |
| 176 | */ |
| 177 | loff_t cat_kms; |
| 178 | /** Modification time. Measured in seconds since epoch. */ |
Arnd Bergmann | 46c360f | 2015-09-27 16:45:02 -0400 | [diff] [blame] | 179 | time64_t cat_mtime; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 180 | /** Access time. Measured in seconds since epoch. */ |
Arnd Bergmann | 46c360f | 2015-09-27 16:45:02 -0400 | [diff] [blame] | 181 | time64_t cat_atime; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 182 | /** Change time. Measured in seconds since epoch. */ |
Arnd Bergmann | 46c360f | 2015-09-27 16:45:02 -0400 | [diff] [blame] | 183 | time64_t cat_ctime; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 184 | /** |
| 185 | * Blocks allocated to this cl_object on the server file system. |
| 186 | * |
| 187 | * \todo XXX An interface for block size is needed. |
| 188 | */ |
| 189 | __u64 cat_blocks; |
| 190 | /** |
| 191 | * User identifier for quota purposes. |
| 192 | */ |
| 193 | uid_t cat_uid; |
| 194 | /** |
| 195 | * Group identifier for quota purposes. |
| 196 | */ |
| 197 | gid_t cat_gid; |
| 198 | }; |
| 199 | |
| 200 | /** |
| 201 | * Fields in cl_attr that are being set. |
| 202 | */ |
| 203 | enum cl_attr_valid { |
| 204 | CAT_SIZE = 1 << 0, |
| 205 | CAT_KMS = 1 << 1, |
| 206 | CAT_MTIME = 1 << 3, |
| 207 | CAT_ATIME = 1 << 4, |
| 208 | CAT_CTIME = 1 << 5, |
| 209 | CAT_BLOCKS = 1 << 6, |
| 210 | CAT_UID = 1 << 7, |
| 211 | CAT_GID = 1 << 8 |
| 212 | }; |
| 213 | |
| 214 | /** |
| 215 | * Sub-class of lu_object with methods common for objects on the client |
| 216 | * stacks. |
| 217 | * |
| 218 | * cl_object: represents a regular file system object, both a file and a |
| 219 | * stripe. cl_object is based on lu_object: it is identified by a fid, |
| 220 | * layered, cached, hashed, and lrued. Important distinction with the server |
| 221 | * side, where md_object and dt_object are used, is that cl_object "fans out" |
| 222 | * at the lov/sns level: depending on the file layout, single file is |
| 223 | * represented as a set of "sub-objects" (stripes). At the implementation |
| 224 | * level, struct lov_object contains an array of cl_objects. Each sub-object |
| 225 | * is a full-fledged cl_object, having its fid, living in the lru and hash |
| 226 | * table. |
| 227 | * |
| 228 | * This leads to the next important difference with the server side: on the |
| 229 | * client, it's quite usual to have objects with the different sequence of |
| 230 | * layers. For example, typical top-object is composed of the following |
| 231 | * layers: |
| 232 | * |
| 233 | * - vvp |
| 234 | * - lov |
| 235 | * |
| 236 | * whereas its sub-objects are composed of |
| 237 | * |
| 238 | * - lovsub |
| 239 | * - osc |
| 240 | * |
| 241 | * layers. Here "lovsub" is a mostly dummy layer, whose purpose is to keep |
| 242 | * track of the object-subobject relationship. |
| 243 | * |
| 244 | * Sub-objects are not cached independently: when top-object is about to |
| 245 | * be discarded from the memory, all its sub-objects are torn-down and |
| 246 | * destroyed too. |
| 247 | * |
John L. Hammond | 8c7b0e1 | 2016-03-30 19:48:47 -0400 | [diff] [blame] | 248 | * \see vvp_object, lov_object, lovsub_object, osc_object |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 249 | */ |
| 250 | struct cl_object { |
| 251 | /** super class */ |
| 252 | struct lu_object co_lu; |
| 253 | /** per-object-layer operations */ |
| 254 | const struct cl_object_operations *co_ops; |
| 255 | /** offset of page slice in cl_page buffer */ |
| 256 | int co_slice_off; |
| 257 | }; |
| 258 | |
| 259 | /** |
| 260 | * Description of the client object configuration. This is used for the |
| 261 | * creation of a new client object that is identified by a more state than |
| 262 | * fid. |
| 263 | */ |
| 264 | struct cl_object_conf { |
| 265 | /** Super-class. */ |
| 266 | struct lu_object_conf coc_lu; |
| 267 | union { |
| 268 | /** |
| 269 | * Object layout. This is consumed by lov. |
| 270 | */ |
| 271 | struct lustre_md *coc_md; |
| 272 | /** |
| 273 | * Description of particular stripe location in the |
| 274 | * cluster. This is consumed by osc. |
| 275 | */ |
| 276 | struct lov_oinfo *coc_oinfo; |
| 277 | } u; |
| 278 | /** |
| 279 | * VFS inode. This is consumed by vvp. |
| 280 | */ |
| 281 | struct inode *coc_inode; |
| 282 | /** |
| 283 | * Layout lock handle. |
| 284 | */ |
| 285 | struct ldlm_lock *coc_lock; |
| 286 | /** |
| 287 | * Operation to handle layout, OBJECT_CONF_XYZ. |
| 288 | */ |
| 289 | int coc_opc; |
| 290 | }; |
| 291 | |
| 292 | enum { |
| 293 | /** configure layout, set up a new stripe, must be called while |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 294 | * holding layout lock. |
| 295 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 296 | OBJECT_CONF_SET = 0, |
| 297 | /** invalidate the current stripe configuration due to losing |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 298 | * layout lock. |
| 299 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 300 | OBJECT_CONF_INVALIDATE = 1, |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 301 | /** wait for old layout to go away so that new layout can be set up. */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 302 | OBJECT_CONF_WAIT = 2 |
| 303 | }; |
| 304 | |
| 305 | /** |
| 306 | * Operations implemented for each cl object layer. |
| 307 | * |
| 308 | * \see vvp_ops, lov_ops, lovsub_ops, osc_ops |
| 309 | */ |
| 310 | struct cl_object_operations { |
| 311 | /** |
| 312 | * Initialize page slice for this layer. Called top-to-bottom through |
| 313 | * every object layer when a new cl_page is instantiated. Layer |
| 314 | * keeping private per-page data, or requiring its own page operations |
| 315 | * vector should allocate these data here, and attach then to the page |
| 316 | * by calling cl_page_slice_add(). \a vmpage is locked (in the VM |
| 317 | * sense). Optional. |
| 318 | * |
| 319 | * \retval NULL success. |
| 320 | * |
| 321 | * \retval ERR_PTR(errno) failure code. |
| 322 | * |
| 323 | * \retval valid-pointer pointer to already existing referenced page |
| 324 | * to be used instead of newly created. |
| 325 | */ |
| 326 | int (*coo_page_init)(const struct lu_env *env, struct cl_object *obj, |
Jinshan Xiong | 7addf40 | 2016-03-30 19:48:32 -0400 | [diff] [blame] | 327 | struct cl_page *page, pgoff_t index); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 328 | /** |
| 329 | * Initialize lock slice for this layer. Called top-to-bottom through |
| 330 | * every object layer when a new cl_lock is instantiated. Layer |
| 331 | * keeping private per-lock data, or requiring its own lock operations |
| 332 | * vector should allocate these data here, and attach then to the lock |
| 333 | * by calling cl_lock_slice_add(). Mandatory. |
| 334 | */ |
| 335 | int (*coo_lock_init)(const struct lu_env *env, |
| 336 | struct cl_object *obj, struct cl_lock *lock, |
| 337 | const struct cl_io *io); |
| 338 | /** |
| 339 | * Initialize io state for a given layer. |
| 340 | * |
| 341 | * called top-to-bottom once per io existence to initialize io |
| 342 | * state. If layer wants to keep some state for this type of io, it |
| 343 | * has to embed struct cl_io_slice in lu_env::le_ses, and register |
| 344 | * slice with cl_io_slice_add(). It is guaranteed that all threads |
| 345 | * participating in this io share the same session. |
| 346 | */ |
| 347 | int (*coo_io_init)(const struct lu_env *env, |
| 348 | struct cl_object *obj, struct cl_io *io); |
| 349 | /** |
| 350 | * Fill portion of \a attr that this layer controls. This method is |
| 351 | * called top-to-bottom through all object layers. |
| 352 | * |
| 353 | * \pre cl_object_header::coh_attr_guard of the top-object is locked. |
| 354 | * |
| 355 | * \return 0: to continue |
| 356 | * \return +ve: to stop iterating through layers (but 0 is returned |
| 357 | * from enclosing cl_object_attr_get()) |
| 358 | * \return -ve: to signal error |
| 359 | */ |
| 360 | int (*coo_attr_get)(const struct lu_env *env, struct cl_object *obj, |
| 361 | struct cl_attr *attr); |
| 362 | /** |
| 363 | * Update attributes. |
| 364 | * |
| 365 | * \a valid is a bitmask composed from enum #cl_attr_valid, and |
| 366 | * indicating what attributes are to be set. |
| 367 | * |
| 368 | * \pre cl_object_header::coh_attr_guard of the top-object is locked. |
| 369 | * |
| 370 | * \return the same convention as for |
| 371 | * cl_object_operations::coo_attr_get() is used. |
| 372 | */ |
| 373 | int (*coo_attr_set)(const struct lu_env *env, struct cl_object *obj, |
| 374 | const struct cl_attr *attr, unsigned valid); |
| 375 | /** |
| 376 | * Update object configuration. Called top-to-bottom to modify object |
| 377 | * configuration. |
| 378 | * |
| 379 | * XXX error conditions and handling. |
| 380 | */ |
| 381 | int (*coo_conf_set)(const struct lu_env *env, struct cl_object *obj, |
| 382 | const struct cl_object_conf *conf); |
| 383 | /** |
| 384 | * Glimpse ast. Executed when glimpse ast arrives for a lock on this |
| 385 | * object. Layers are supposed to fill parts of \a lvb that will be |
| 386 | * shipped to the glimpse originator as a glimpse result. |
| 387 | * |
John L. Hammond | 8c7b0e1 | 2016-03-30 19:48:47 -0400 | [diff] [blame] | 388 | * \see vvp_object_glimpse(), lovsub_object_glimpse(), |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 389 | * \see osc_object_glimpse() |
| 390 | */ |
| 391 | int (*coo_glimpse)(const struct lu_env *env, |
| 392 | const struct cl_object *obj, struct ost_lvb *lvb); |
Jinshan Xiong | d9d4790 | 2016-03-30 19:48:28 -0400 | [diff] [blame] | 393 | /** |
| 394 | * Object prune method. Called when the layout is going to change on |
| 395 | * this object, therefore each layer has to clean up their cache, |
| 396 | * mainly pages and locks. |
| 397 | */ |
| 398 | int (*coo_prune)(const struct lu_env *env, struct cl_object *obj); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 399 | }; |
| 400 | |
| 401 | /** |
| 402 | * Extended header for client object. |
| 403 | */ |
| 404 | struct cl_object_header { |
| 405 | /** Standard lu_object_header. cl_object::co_lu::lo_header points |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 406 | * here. |
| 407 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 408 | struct lu_object_header coh_lu; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 409 | |
| 410 | /** |
| 411 | * Parent object. It is assumed that an object has a well-defined |
| 412 | * parent, but not a well-defined child (there may be multiple |
| 413 | * sub-objects, for the same top-object). cl_object_header::coh_parent |
| 414 | * field allows certain code to be written generically, without |
| 415 | * limiting possible cl_object layouts unduly. |
| 416 | */ |
| 417 | struct cl_object_header *coh_parent; |
| 418 | /** |
| 419 | * Protects consistency between cl_attr of parent object and |
| 420 | * attributes of sub-objects, that the former is calculated ("merged") |
| 421 | * from. |
| 422 | * |
| 423 | * \todo XXX this can be read/write lock if needed. |
| 424 | */ |
| 425 | spinlock_t coh_attr_guard; |
| 426 | /** |
| 427 | * Size of cl_page + page slices |
| 428 | */ |
| 429 | unsigned short coh_page_bufsize; |
| 430 | /** |
| 431 | * Number of objects above this one: 0 for a top-object, 1 for its |
| 432 | * sub-object, etc. |
| 433 | */ |
| 434 | unsigned char coh_nesting; |
| 435 | }; |
| 436 | |
| 437 | /** |
| 438 | * Helper macro: iterate over all layers of the object \a obj, assigning every |
| 439 | * layer top-to-bottom to \a slice. |
| 440 | */ |
| 441 | #define cl_object_for_each(slice, obj) \ |
| 442 | list_for_each_entry((slice), \ |
| 443 | &(obj)->co_lu.lo_header->loh_layers, \ |
| 444 | co_lu.lo_linkage) |
| 445 | /** |
| 446 | * Helper macro: iterate over all layers of the object \a obj, assigning every |
| 447 | * layer bottom-to-top to \a slice. |
| 448 | */ |
| 449 | #define cl_object_for_each_reverse(slice, obj) \ |
| 450 | list_for_each_entry_reverse((slice), \ |
| 451 | &(obj)->co_lu.lo_header->loh_layers, \ |
| 452 | co_lu.lo_linkage) |
| 453 | /** @} cl_object */ |
| 454 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 455 | #define CL_PAGE_EOF ((pgoff_t)~0ull) |
| 456 | |
| 457 | /** \addtogroup cl_page cl_page |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 458 | * @{ |
| 459 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 460 | |
| 461 | /** \struct cl_page |
| 462 | * Layered client page. |
| 463 | * |
| 464 | * cl_page: represents a portion of a file, cached in the memory. All pages |
| 465 | * of the given file are of the same size, and are kept in the radix tree |
| 466 | * hanging off the cl_object. cl_page doesn't fan out, but as sub-objects |
| 467 | * of the top-level file object are first class cl_objects, they have their |
| 468 | * own radix trees of pages and hence page is implemented as a sequence of |
| 469 | * struct cl_pages's, linked into double-linked list through |
| 470 | * cl_page::cp_parent and cl_page::cp_child pointers, each residing in the |
| 471 | * corresponding radix tree at the corresponding logical offset. |
| 472 | * |
| 473 | * cl_page is associated with VM page of the hosting environment (struct |
| 474 | * page in Linux kernel, for example), struct page. It is assumed, that this |
| 475 | * association is implemented by one of cl_page layers (top layer in the |
| 476 | * current design) that |
| 477 | * |
| 478 | * - intercepts per-VM-page call-backs made by the environment (e.g., |
| 479 | * memory pressure), |
| 480 | * |
| 481 | * - translates state (page flag bits) and locking between lustre and |
| 482 | * environment. |
| 483 | * |
| 484 | * The association between cl_page and struct page is immutable and |
| 485 | * established when cl_page is created. |
| 486 | * |
| 487 | * cl_page can be "owned" by a particular cl_io (see below), guaranteeing |
| 488 | * this io an exclusive access to this page w.r.t. other io attempts and |
| 489 | * various events changing page state (such as transfer completion, or |
| 490 | * eviction of the page from the memory). Note, that in general cl_io |
| 491 | * cannot be identified with a particular thread, and page ownership is not |
| 492 | * exactly equal to the current thread holding a lock on the page. Layer |
| 493 | * implementing association between cl_page and struct page has to implement |
| 494 | * ownership on top of available synchronization mechanisms. |
| 495 | * |
| 496 | * While lustre client maintains the notion of an page ownership by io, |
| 497 | * hosting MM/VM usually has its own page concurrency control |
| 498 | * mechanisms. For example, in Linux, page access is synchronized by the |
| 499 | * per-page PG_locked bit-lock, and generic kernel code (generic_file_*()) |
| 500 | * takes care to acquire and release such locks as necessary around the |
| 501 | * calls to the file system methods (->readpage(), ->prepare_write(), |
| 502 | * ->commit_write(), etc.). This leads to the situation when there are two |
| 503 | * different ways to own a page in the client: |
| 504 | * |
| 505 | * - client code explicitly and voluntary owns the page (cl_page_own()); |
| 506 | * |
| 507 | * - VM locks a page and then calls the client, that has "to assume" |
| 508 | * the ownership from the VM (cl_page_assume()). |
| 509 | * |
| 510 | * Dual methods to release ownership are cl_page_disown() and |
| 511 | * cl_page_unassume(). |
| 512 | * |
| 513 | * cl_page is reference counted (cl_page::cp_ref). When reference counter |
| 514 | * drops to 0, the page is returned to the cache, unless it is in |
| 515 | * cl_page_state::CPS_FREEING state, in which case it is immediately |
| 516 | * destroyed. |
| 517 | * |
| 518 | * The general logic guaranteeing the absence of "existential races" for |
| 519 | * pages is the following: |
| 520 | * |
| 521 | * - there are fixed known ways for a thread to obtain a new reference |
| 522 | * to a page: |
| 523 | * |
| 524 | * - by doing a lookup in the cl_object radix tree, protected by the |
| 525 | * spin-lock; |
| 526 | * |
| 527 | * - by starting from VM-locked struct page and following some |
| 528 | * hosting environment method (e.g., following ->private pointer in |
| 529 | * the case of Linux kernel), see cl_vmpage_page(); |
| 530 | * |
| 531 | * - when the page enters cl_page_state::CPS_FREEING state, all these |
| 532 | * ways are severed with the proper synchronization |
| 533 | * (cl_page_delete()); |
| 534 | * |
| 535 | * - entry into cl_page_state::CPS_FREEING is serialized by the VM page |
| 536 | * lock; |
| 537 | * |
| 538 | * - no new references to the page in cl_page_state::CPS_FREEING state |
| 539 | * are allowed (checked in cl_page_get()). |
| 540 | * |
| 541 | * Together this guarantees that when last reference to a |
| 542 | * cl_page_state::CPS_FREEING page is released, it is safe to destroy the |
| 543 | * page, as neither references to it can be acquired at that point, nor |
| 544 | * ones exist. |
| 545 | * |
| 546 | * cl_page is a state machine. States are enumerated in enum |
| 547 | * cl_page_state. Possible state transitions are enumerated in |
| 548 | * cl_page_state_set(). State transition process (i.e., actual changing of |
| 549 | * cl_page::cp_state field) is protected by the lock on the underlying VM |
| 550 | * page. |
| 551 | * |
| 552 | * Linux Kernel implementation. |
| 553 | * |
| 554 | * Binding between cl_page and struct page (which is a typedef for |
| 555 | * struct page) is implemented in the vvp layer. cl_page is attached to the |
| 556 | * ->private pointer of the struct page, together with the setting of |
| 557 | * PG_private bit in page->flags, and acquiring additional reference on the |
| 558 | * struct page (much like struct buffer_head, or any similar file system |
| 559 | * private data structures). |
| 560 | * |
| 561 | * PG_locked lock is used to implement both ownership and transfer |
| 562 | * synchronization, that is, page is VM-locked in CPS_{OWNED,PAGE{IN,OUT}} |
| 563 | * states. No additional references are acquired for the duration of the |
| 564 | * transfer. |
| 565 | * |
| 566 | * \warning *THIS IS NOT* the behavior expected by the Linux kernel, where |
| 567 | * write-out is "protected" by the special PG_writeback bit. |
| 568 | */ |
| 569 | |
| 570 | /** |
| 571 | * States of cl_page. cl_page.c assumes particular order here. |
| 572 | * |
| 573 | * The page state machine is rather crude, as it doesn't recognize finer page |
| 574 | * states like "dirty" or "up to date". This is because such states are not |
| 575 | * always well defined for the whole stack (see, for example, the |
| 576 | * implementation of the read-ahead, that hides page up-to-dateness to track |
| 577 | * cache hits accurately). Such sub-states are maintained by the layers that |
| 578 | * are interested in them. |
| 579 | */ |
| 580 | enum cl_page_state { |
| 581 | /** |
| 582 | * Page is in the cache, un-owned. Page leaves cached state in the |
| 583 | * following cases: |
| 584 | * |
| 585 | * - [cl_page_state::CPS_OWNED] io comes across the page and |
| 586 | * owns it; |
| 587 | * |
| 588 | * - [cl_page_state::CPS_PAGEOUT] page is dirty, the |
| 589 | * req-formation engine decides that it wants to include this page |
| 590 | * into an cl_req being constructed, and yanks it from the cache; |
| 591 | * |
| 592 | * - [cl_page_state::CPS_FREEING] VM callback is executed to |
| 593 | * evict the page form the memory; |
| 594 | * |
| 595 | * \invariant cl_page::cp_owner == NULL && cl_page::cp_req == NULL |
| 596 | */ |
| 597 | CPS_CACHED, |
| 598 | /** |
| 599 | * Page is exclusively owned by some cl_io. Page may end up in this |
| 600 | * state as a result of |
| 601 | * |
| 602 | * - io creating new page and immediately owning it; |
| 603 | * |
| 604 | * - [cl_page_state::CPS_CACHED] io finding existing cached page |
| 605 | * and owning it; |
| 606 | * |
| 607 | * - [cl_page_state::CPS_OWNED] io finding existing owned page |
| 608 | * and waiting for owner to release the page; |
| 609 | * |
| 610 | * Page leaves owned state in the following cases: |
| 611 | * |
| 612 | * - [cl_page_state::CPS_CACHED] io decides to leave the page in |
| 613 | * the cache, doing nothing; |
| 614 | * |
| 615 | * - [cl_page_state::CPS_PAGEIN] io starts read transfer for |
| 616 | * this page; |
| 617 | * |
| 618 | * - [cl_page_state::CPS_PAGEOUT] io starts immediate write |
| 619 | * transfer for this page; |
| 620 | * |
| 621 | * - [cl_page_state::CPS_FREEING] io decides to destroy this |
| 622 | * page (e.g., as part of truncate or extent lock cancellation). |
| 623 | * |
| 624 | * \invariant cl_page::cp_owner != NULL && cl_page::cp_req == NULL |
| 625 | */ |
| 626 | CPS_OWNED, |
| 627 | /** |
| 628 | * Page is being written out, as a part of a transfer. This state is |
| 629 | * entered when req-formation logic decided that it wants this page to |
| 630 | * be sent through the wire _now_. Specifically, it means that once |
| 631 | * this state is achieved, transfer completion handler (with either |
| 632 | * success or failure indication) is guaranteed to be executed against |
| 633 | * this page independently of any locks and any scheduling decisions |
| 634 | * made by the hosting environment (that effectively means that the |
| 635 | * page is never put into cl_page_state::CPS_PAGEOUT state "in |
| 636 | * advance". This property is mentioned, because it is important when |
| 637 | * reasoning about possible dead-locks in the system). The page can |
| 638 | * enter this state as a result of |
| 639 | * |
| 640 | * - [cl_page_state::CPS_OWNED] an io requesting an immediate |
| 641 | * write-out of this page, or |
| 642 | * |
| 643 | * - [cl_page_state::CPS_CACHED] req-forming engine deciding |
| 644 | * that it has enough dirty pages cached to issue a "good" |
| 645 | * transfer. |
| 646 | * |
| 647 | * The page leaves cl_page_state::CPS_PAGEOUT state when the transfer |
| 648 | * is completed---it is moved into cl_page_state::CPS_CACHED state. |
| 649 | * |
| 650 | * Underlying VM page is locked for the duration of transfer. |
| 651 | * |
| 652 | * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL |
| 653 | */ |
| 654 | CPS_PAGEOUT, |
| 655 | /** |
| 656 | * Page is being read in, as a part of a transfer. This is quite |
| 657 | * similar to the cl_page_state::CPS_PAGEOUT state, except that |
| 658 | * read-in is always "immediate"---there is no such thing a sudden |
| 659 | * construction of read cl_req from cached, presumably not up to date, |
| 660 | * pages. |
| 661 | * |
| 662 | * Underlying VM page is locked for the duration of transfer. |
| 663 | * |
| 664 | * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req != NULL |
| 665 | */ |
| 666 | CPS_PAGEIN, |
| 667 | /** |
| 668 | * Page is being destroyed. This state is entered when client decides |
| 669 | * that page has to be deleted from its host object, as, e.g., a part |
| 670 | * of truncate. |
| 671 | * |
| 672 | * Once this state is reached, there is no way to escape it. |
| 673 | * |
| 674 | * \invariant: cl_page::cp_owner == NULL && cl_page::cp_req == NULL |
| 675 | */ |
| 676 | CPS_FREEING, |
| 677 | CPS_NR |
| 678 | }; |
| 679 | |
| 680 | enum cl_page_type { |
| 681 | /** Host page, the page is from the host inode which the cl_page |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 682 | * belongs to. |
| 683 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 684 | CPT_CACHEABLE = 1, |
| 685 | |
| 686 | /** Transient page, the transient cl_page is used to bind a cl_page |
| 687 | * to vmpage which is not belonging to the same object of cl_page. |
Oleg Drokin | 85f552d | 2016-02-26 01:49:56 -0500 | [diff] [blame] | 688 | * it is used in DirectIO and lockless IO. |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 689 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 690 | CPT_TRANSIENT, |
| 691 | }; |
| 692 | |
| 693 | /** |
| 694 | * Flags maintained for every cl_page. |
| 695 | */ |
| 696 | enum cl_page_flags { |
| 697 | /** |
| 698 | * Set when pagein completes. Used for debugging (read completes at |
| 699 | * most once for a page). |
| 700 | */ |
| 701 | CPF_READ_COMPLETED = 1 << 0 |
| 702 | }; |
| 703 | |
| 704 | /** |
| 705 | * Fields are protected by the lock on struct page, except for atomics and |
| 706 | * immutables. |
| 707 | * |
| 708 | * \invariant Data type invariants are in cl_page_invariant(). Basically: |
| 709 | * cl_page::cp_parent and cl_page::cp_child are a well-formed double-linked |
| 710 | * list, consistent with the parent/child pointers in the cl_page::cp_obj and |
| 711 | * cl_page::cp_owner (when set). |
| 712 | */ |
| 713 | struct cl_page { |
| 714 | /** Reference counter. */ |
| 715 | atomic_t cp_ref; |
| 716 | /** An object this page is a part of. Immutable after creation. */ |
| 717 | struct cl_object *cp_obj; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 718 | /** List of slices. Immutable after creation. */ |
| 719 | struct list_head cp_layers; |
Jinshan Xiong | 7addf40 | 2016-03-30 19:48:32 -0400 | [diff] [blame] | 720 | /** vmpage */ |
| 721 | struct page *cp_vmpage; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 722 | /** |
| 723 | * Page state. This field is const to avoid accidental update, it is |
| 724 | * modified only internally within cl_page.c. Protected by a VM lock. |
| 725 | */ |
| 726 | const enum cl_page_state cp_state; |
| 727 | /** Linkage of pages within group. Protected by cl_page::cp_mutex. */ |
| 728 | struct list_head cp_batch; |
| 729 | /** Mutex serializing membership of a page in a batch. */ |
| 730 | struct mutex cp_mutex; |
| 731 | /** Linkage of pages within cl_req. */ |
| 732 | struct list_head cp_flight; |
| 733 | /** Transfer error. */ |
| 734 | int cp_error; |
| 735 | |
| 736 | /** |
| 737 | * Page type. Only CPT_TRANSIENT is used so far. Immutable after |
| 738 | * creation. |
| 739 | */ |
| 740 | enum cl_page_type cp_type; |
| 741 | |
| 742 | /** |
| 743 | * Owning IO in cl_page_state::CPS_OWNED state. Sub-page can be owned |
| 744 | * by sub-io. Protected by a VM lock. |
| 745 | */ |
| 746 | struct cl_io *cp_owner; |
| 747 | /** |
| 748 | * Debug information, the task is owning the page. |
| 749 | */ |
Greg Kroah-Hartman | 68b636b | 2013-08-04 08:56:42 +0800 | [diff] [blame] | 750 | struct task_struct *cp_task; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 751 | /** |
| 752 | * Owning IO request in cl_page_state::CPS_PAGEOUT and |
| 753 | * cl_page_state::CPS_PAGEIN states. This field is maintained only in |
| 754 | * the top-level pages. Protected by a VM lock. |
| 755 | */ |
| 756 | struct cl_req *cp_req; |
| 757 | /** List of references to this page, for debugging. */ |
| 758 | struct lu_ref cp_reference; |
| 759 | /** Link to an object, for debugging. */ |
John L. Hammond | 631abc6 | 2013-07-25 01:17:30 +0800 | [diff] [blame] | 760 | struct lu_ref_link cp_obj_ref; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 761 | /** Link to a queue, for debugging. */ |
John L. Hammond | 631abc6 | 2013-07-25 01:17:30 +0800 | [diff] [blame] | 762 | struct lu_ref_link cp_queue_ref; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 763 | /** Per-page flags from enum cl_page_flags. Protected by a VM lock. */ |
John L. Hammond | 631abc6 | 2013-07-25 01:17:30 +0800 | [diff] [blame] | 764 | unsigned cp_flags; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 765 | /** Assigned if doing a sync_io */ |
| 766 | struct cl_sync_io *cp_sync_io; |
| 767 | }; |
| 768 | |
| 769 | /** |
| 770 | * Per-layer part of cl_page. |
| 771 | * |
John L. Hammond | 3a52f80 | 2016-03-30 19:48:48 -0400 | [diff] [blame] | 772 | * \see vvp_page, lov_page, osc_page |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 773 | */ |
| 774 | struct cl_page_slice { |
| 775 | struct cl_page *cpl_page; |
Jinshan Xiong | 7addf40 | 2016-03-30 19:48:32 -0400 | [diff] [blame] | 776 | pgoff_t cpl_index; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 777 | /** |
| 778 | * Object slice corresponding to this page slice. Immutable after |
| 779 | * creation. |
| 780 | */ |
| 781 | struct cl_object *cpl_obj; |
| 782 | const struct cl_page_operations *cpl_ops; |
| 783 | /** Linkage into cl_page::cp_layers. Immutable after creation. */ |
| 784 | struct list_head cpl_linkage; |
| 785 | }; |
| 786 | |
| 787 | /** |
| 788 | * Lock mode. For the client extent locks. |
| 789 | * |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 790 | * \ingroup cl_lock |
| 791 | */ |
| 792 | enum cl_lock_mode { |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 793 | CLM_READ, |
| 794 | CLM_WRITE, |
| 795 | CLM_GROUP |
| 796 | }; |
| 797 | |
| 798 | /** |
| 799 | * Requested transfer type. |
| 800 | * \ingroup cl_req |
| 801 | */ |
| 802 | enum cl_req_type { |
| 803 | CRT_READ, |
| 804 | CRT_WRITE, |
| 805 | CRT_NR |
| 806 | }; |
| 807 | |
| 808 | /** |
| 809 | * Per-layer page operations. |
| 810 | * |
| 811 | * Methods taking an \a io argument are for the activity happening in the |
| 812 | * context of given \a io. Page is assumed to be owned by that io, except for |
| 813 | * the obvious cases (like cl_page_operations::cpo_own()). |
| 814 | * |
| 815 | * \see vvp_page_ops, lov_page_ops, osc_page_ops |
| 816 | */ |
| 817 | struct cl_page_operations { |
| 818 | /** |
| 819 | * cl_page<->struct page methods. Only one layer in the stack has to |
| 820 | * implement these. Current code assumes that this functionality is |
| 821 | * provided by the topmost layer, see cl_page_disown0() as an example. |
| 822 | */ |
| 823 | |
| 824 | /** |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 825 | * Called when \a io acquires this page into the exclusive |
| 826 | * ownership. When this method returns, it is guaranteed that the is |
| 827 | * not owned by other io, and no transfer is going on against |
| 828 | * it. Optional. |
| 829 | * |
| 830 | * \see cl_page_own() |
| 831 | * \see vvp_page_own(), lov_page_own() |
| 832 | */ |
| 833 | int (*cpo_own)(const struct lu_env *env, |
| 834 | const struct cl_page_slice *slice, |
| 835 | struct cl_io *io, int nonblock); |
| 836 | /** Called when ownership it yielded. Optional. |
| 837 | * |
| 838 | * \see cl_page_disown() |
| 839 | * \see vvp_page_disown() |
| 840 | */ |
| 841 | void (*cpo_disown)(const struct lu_env *env, |
| 842 | const struct cl_page_slice *slice, struct cl_io *io); |
| 843 | /** |
| 844 | * Called for a page that is already "owned" by \a io from VM point of |
| 845 | * view. Optional. |
| 846 | * |
| 847 | * \see cl_page_assume() |
| 848 | * \see vvp_page_assume(), lov_page_assume() |
| 849 | */ |
| 850 | void (*cpo_assume)(const struct lu_env *env, |
| 851 | const struct cl_page_slice *slice, struct cl_io *io); |
| 852 | /** Dual to cl_page_operations::cpo_assume(). Optional. Called |
| 853 | * bottom-to-top when IO releases a page without actually unlocking |
| 854 | * it. |
| 855 | * |
| 856 | * \see cl_page_unassume() |
| 857 | * \see vvp_page_unassume() |
| 858 | */ |
| 859 | void (*cpo_unassume)(const struct lu_env *env, |
| 860 | const struct cl_page_slice *slice, |
| 861 | struct cl_io *io); |
| 862 | /** |
| 863 | * Announces whether the page contains valid data or not by \a uptodate. |
| 864 | * |
| 865 | * \see cl_page_export() |
| 866 | * \see vvp_page_export() |
| 867 | */ |
| 868 | void (*cpo_export)(const struct lu_env *env, |
| 869 | const struct cl_page_slice *slice, int uptodate); |
| 870 | /** |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 871 | * Checks whether underlying VM page is locked (in the suitable |
| 872 | * sense). Used for assertions. |
| 873 | * |
| 874 | * \retval -EBUSY: page is protected by a lock of a given mode; |
| 875 | * \retval -ENODATA: page is not protected by a lock; |
| 876 | * \retval 0: this layer cannot decide. (Should never happen.) |
| 877 | */ |
| 878 | int (*cpo_is_vmlocked)(const struct lu_env *env, |
| 879 | const struct cl_page_slice *slice); |
| 880 | /** |
| 881 | * Page destruction. |
| 882 | */ |
| 883 | |
| 884 | /** |
| 885 | * Called when page is truncated from the object. Optional. |
| 886 | * |
| 887 | * \see cl_page_discard() |
| 888 | * \see vvp_page_discard(), osc_page_discard() |
| 889 | */ |
| 890 | void (*cpo_discard)(const struct lu_env *env, |
| 891 | const struct cl_page_slice *slice, |
| 892 | struct cl_io *io); |
| 893 | /** |
| 894 | * Called when page is removed from the cache, and is about to being |
| 895 | * destroyed. Optional. |
| 896 | * |
| 897 | * \see cl_page_delete() |
| 898 | * \see vvp_page_delete(), osc_page_delete() |
| 899 | */ |
| 900 | void (*cpo_delete)(const struct lu_env *env, |
| 901 | const struct cl_page_slice *slice); |
| 902 | /** Destructor. Frees resources and slice itself. */ |
| 903 | void (*cpo_fini)(const struct lu_env *env, |
| 904 | struct cl_page_slice *slice); |
| 905 | |
| 906 | /** |
| 907 | * Checks whether the page is protected by a cl_lock. This is a |
| 908 | * per-layer method, because certain layers have ways to check for the |
| 909 | * lock much more efficiently than through the generic locks scan, or |
| 910 | * implement locking mechanisms separate from cl_lock, e.g., |
| 911 | * LL_FILE_GROUP_LOCKED in vvp. If \a pending is true, check for locks |
| 912 | * being canceled, or scheduled for cancellation as soon as the last |
| 913 | * user goes away, too. |
| 914 | * |
| 915 | * \retval -EBUSY: page is protected by a lock of a given mode; |
| 916 | * \retval -ENODATA: page is not protected by a lock; |
| 917 | * \retval 0: this layer cannot decide. |
| 918 | * |
| 919 | * \see cl_page_is_under_lock() |
| 920 | */ |
| 921 | int (*cpo_is_under_lock)(const struct lu_env *env, |
| 922 | const struct cl_page_slice *slice, |
Jinshan Xiong | fd7444f | 2016-03-30 19:48:33 -0400 | [diff] [blame] | 923 | struct cl_io *io, pgoff_t *max); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 924 | |
| 925 | /** |
| 926 | * Optional debugging helper. Prints given page slice. |
| 927 | * |
| 928 | * \see cl_page_print() |
| 929 | */ |
| 930 | int (*cpo_print)(const struct lu_env *env, |
| 931 | const struct cl_page_slice *slice, |
| 932 | void *cookie, lu_printer_t p); |
| 933 | /** |
| 934 | * \name transfer |
| 935 | * |
| 936 | * Transfer methods. See comment on cl_req for a description of |
| 937 | * transfer formation and life-cycle. |
| 938 | * |
| 939 | * @{ |
| 940 | */ |
| 941 | /** |
| 942 | * Request type dependent vector of operations. |
| 943 | * |
| 944 | * Transfer operations depend on transfer mode (cl_req_type). To avoid |
| 945 | * passing transfer mode to each and every of these methods, and to |
| 946 | * avoid branching on request type inside of the methods, separate |
| 947 | * methods for cl_req_type:CRT_READ and cl_req_type:CRT_WRITE are |
| 948 | * provided. That is, method invocation usually looks like |
| 949 | * |
| 950 | * slice->cp_ops.io[req->crq_type].cpo_method(env, slice, ...); |
| 951 | */ |
| 952 | struct { |
| 953 | /** |
| 954 | * Called when a page is submitted for a transfer as a part of |
| 955 | * cl_page_list. |
| 956 | * |
| 957 | * \return 0 : page is eligible for submission; |
| 958 | * \return -EALREADY : skip this page; |
| 959 | * \return -ve : error. |
| 960 | * |
| 961 | * \see cl_page_prep() |
| 962 | */ |
| 963 | int (*cpo_prep)(const struct lu_env *env, |
| 964 | const struct cl_page_slice *slice, |
| 965 | struct cl_io *io); |
| 966 | /** |
| 967 | * Completion handler. This is guaranteed to be eventually |
| 968 | * fired after cl_page_operations::cpo_prep() or |
| 969 | * cl_page_operations::cpo_make_ready() call. |
| 970 | * |
| 971 | * This method can be called in a non-blocking context. It is |
| 972 | * guaranteed however, that the page involved and its object |
| 973 | * are pinned in memory (and, hence, calling cl_page_put() is |
| 974 | * safe). |
| 975 | * |
| 976 | * \see cl_page_completion() |
| 977 | */ |
| 978 | void (*cpo_completion)(const struct lu_env *env, |
| 979 | const struct cl_page_slice *slice, |
| 980 | int ioret); |
| 981 | /** |
| 982 | * Called when cached page is about to be added to the |
| 983 | * cl_req as a part of req formation. |
| 984 | * |
| 985 | * \return 0 : proceed with this page; |
| 986 | * \return -EAGAIN : skip this page; |
| 987 | * \return -ve : error. |
| 988 | * |
| 989 | * \see cl_page_make_ready() |
| 990 | */ |
| 991 | int (*cpo_make_ready)(const struct lu_env *env, |
| 992 | const struct cl_page_slice *slice); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 993 | } io[CRT_NR]; |
| 994 | /** |
| 995 | * Tell transfer engine that only [to, from] part of a page should be |
| 996 | * transmitted. |
| 997 | * |
| 998 | * This is used for immediate transfers. |
| 999 | * |
| 1000 | * \todo XXX this is not very good interface. It would be much better |
| 1001 | * if all transfer parameters were supplied as arguments to |
| 1002 | * cl_io_operations::cio_submit() call, but it is not clear how to do |
| 1003 | * this for page queues. |
| 1004 | * |
| 1005 | * \see cl_page_clip() |
| 1006 | */ |
| 1007 | void (*cpo_clip)(const struct lu_env *env, |
| 1008 | const struct cl_page_slice *slice, |
| 1009 | int from, int to); |
| 1010 | /** |
| 1011 | * \pre the page was queued for transferring. |
| 1012 | * \post page is removed from client's pending list, or -EBUSY |
| 1013 | * is returned if it has already been in transferring. |
| 1014 | * |
| 1015 | * This is one of seldom page operation which is: |
| 1016 | * 0. called from top level; |
| 1017 | * 1. don't have vmpage locked; |
| 1018 | * 2. every layer should synchronize execution of its ->cpo_cancel() |
| 1019 | * with completion handlers. Osc uses client obd lock for this |
| 1020 | * purpose. Based on there is no vvp_page_cancel and |
| 1021 | * lov_page_cancel(), cpo_cancel is defacto protected by client lock. |
| 1022 | * |
| 1023 | * \see osc_page_cancel(). |
| 1024 | */ |
| 1025 | int (*cpo_cancel)(const struct lu_env *env, |
| 1026 | const struct cl_page_slice *slice); |
| 1027 | /** |
| 1028 | * Write out a page by kernel. This is only called by ll_writepage |
| 1029 | * right now. |
| 1030 | * |
| 1031 | * \see cl_page_flush() |
| 1032 | */ |
| 1033 | int (*cpo_flush)(const struct lu_env *env, |
| 1034 | const struct cl_page_slice *slice, |
| 1035 | struct cl_io *io); |
| 1036 | /** @} transfer */ |
| 1037 | }; |
| 1038 | |
| 1039 | /** |
| 1040 | * Helper macro, dumping detailed information about \a page into a log. |
| 1041 | */ |
| 1042 | #define CL_PAGE_DEBUG(mask, env, page, format, ...) \ |
| 1043 | do { \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1044 | if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ |
Oleg Drokin | 83e8d02 | 2016-04-28 12:07:31 -0400 | [diff] [blame] | 1045 | LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1046 | cl_page_print(env, &msgdata, lu_cdebug_printer, page); \ |
Mike Rapoport | b2952d6 | 2015-09-03 11:49:13 +0300 | [diff] [blame] | 1047 | CDEBUG(mask, format, ## __VA_ARGS__); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1048 | } \ |
| 1049 | } while (0) |
| 1050 | |
| 1051 | /** |
| 1052 | * Helper macro, dumping shorter information about \a page into a log. |
| 1053 | */ |
| 1054 | #define CL_PAGE_HEADER(mask, env, page, format, ...) \ |
| 1055 | do { \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1056 | if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ |
Oleg Drokin | 83e8d02 | 2016-04-28 12:07:31 -0400 | [diff] [blame] | 1057 | LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1058 | cl_page_header_print(env, &msgdata, lu_cdebug_printer, page); \ |
Mike Rapoport | b2952d6 | 2015-09-03 11:49:13 +0300 | [diff] [blame] | 1059 | CDEBUG(mask, format, ## __VA_ARGS__); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1060 | } \ |
| 1061 | } while (0) |
| 1062 | |
| 1063 | static inline int __page_in_use(const struct cl_page *page, int refc) |
| 1064 | { |
| 1065 | if (page->cp_type == CPT_CACHEABLE) |
| 1066 | ++refc; |
| 1067 | LASSERT(atomic_read(&page->cp_ref) > 0); |
| 1068 | return (atomic_read(&page->cp_ref) > refc); |
| 1069 | } |
Mike Rapoport | c9f6bb9 | 2015-10-13 16:03:42 +0300 | [diff] [blame] | 1070 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1071 | #define cl_page_in_use(pg) __page_in_use(pg, 1) |
| 1072 | #define cl_page_in_use_noref(pg) __page_in_use(pg, 0) |
| 1073 | |
Jinshan Xiong | 7addf40 | 2016-03-30 19:48:32 -0400 | [diff] [blame] | 1074 | static inline struct page *cl_page_vmpage(struct cl_page *page) |
| 1075 | { |
| 1076 | LASSERT(page->cp_vmpage); |
| 1077 | return page->cp_vmpage; |
| 1078 | } |
| 1079 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1080 | /** @} cl_page */ |
| 1081 | |
| 1082 | /** \addtogroup cl_lock cl_lock |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 1083 | * @{ |
| 1084 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1085 | /** \struct cl_lock |
| 1086 | * |
| 1087 | * Extent locking on the client. |
| 1088 | * |
| 1089 | * LAYERING |
| 1090 | * |
| 1091 | * The locking model of the new client code is built around |
| 1092 | * |
| 1093 | * struct cl_lock |
| 1094 | * |
| 1095 | * data-type representing an extent lock on a regular file. cl_lock is a |
| 1096 | * layered object (much like cl_object and cl_page), it consists of a header |
| 1097 | * (struct cl_lock) and a list of layers (struct cl_lock_slice), linked to |
| 1098 | * cl_lock::cll_layers list through cl_lock_slice::cls_linkage. |
| 1099 | * |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1100 | * Typical cl_lock consists of the two layers: |
| 1101 | * |
| 1102 | * - vvp_lock (vvp specific data), and |
| 1103 | * - lov_lock (lov specific data). |
| 1104 | * |
| 1105 | * lov_lock contains an array of sub-locks. Each of these sub-locks is a |
| 1106 | * normal cl_lock: it has a header (struct cl_lock) and a list of layers: |
| 1107 | * |
| 1108 | * - lovsub_lock, and |
| 1109 | * - osc_lock |
| 1110 | * |
| 1111 | * Each sub-lock is associated with a cl_object (representing stripe |
| 1112 | * sub-object or the file to which top-level cl_lock is associated to), and is |
| 1113 | * linked into that cl_object::coh_locks. In this respect cl_lock is similar to |
| 1114 | * cl_object (that at lov layer also fans out into multiple sub-objects), and |
| 1115 | * is different from cl_page, that doesn't fan out (there is usually exactly |
| 1116 | * one osc_page for every vvp_page). We shall call vvp-lov portion of the lock |
| 1117 | * a "top-lock" and its lovsub-osc portion a "sub-lock". |
| 1118 | * |
| 1119 | * LIFE CYCLE |
| 1120 | * |
Bobi Jam | 71a96a0 | 2016-03-30 19:48:41 -0400 | [diff] [blame] | 1121 | * cl_lock is a cacheless data container for the requirements of locks to |
| 1122 | * complete the IO. cl_lock is created before I/O starts and destroyed when the |
| 1123 | * I/O is complete. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1124 | * |
Bobi Jam | 71a96a0 | 2016-03-30 19:48:41 -0400 | [diff] [blame] | 1125 | * cl_lock depends on LDLM lock to fulfill lock semantics. LDLM lock is attached |
| 1126 | * to cl_lock at OSC layer. LDLM lock is still cacheable. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1127 | * |
| 1128 | * INTERFACE AND USAGE |
| 1129 | * |
Bobi Jam | 71a96a0 | 2016-03-30 19:48:41 -0400 | [diff] [blame] | 1130 | * Two major methods are supported for cl_lock: clo_enqueue and clo_cancel. A |
| 1131 | * cl_lock is enqueued by cl_lock_request(), which will call clo_enqueue() |
| 1132 | * methods for each layer to enqueue the lock. At the LOV layer, if a cl_lock |
| 1133 | * consists of multiple sub cl_locks, each sub locks will be enqueued |
| 1134 | * correspondingly. At OSC layer, the lock enqueue request will tend to reuse |
| 1135 | * cached LDLM lock; otherwise a new LDLM lock will have to be requested from |
| 1136 | * OST side. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1137 | * |
Bobi Jam | 71a96a0 | 2016-03-30 19:48:41 -0400 | [diff] [blame] | 1138 | * cl_lock_cancel() must be called to release a cl_lock after use. clo_cancel() |
| 1139 | * method will be called for each layer to release the resource held by this |
| 1140 | * lock. At OSC layer, the reference count of LDLM lock, which is held at |
| 1141 | * clo_enqueue time, is released. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1142 | * |
Bobi Jam | 71a96a0 | 2016-03-30 19:48:41 -0400 | [diff] [blame] | 1143 | * LDLM lock can only be canceled if there is no cl_lock using it. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1144 | * |
| 1145 | * Overall process of the locking during IO operation is as following: |
| 1146 | * |
| 1147 | * - once parameters for IO are setup in cl_io, cl_io_operations::cio_lock() |
| 1148 | * is called on each layer. Responsibility of this method is to add locks, |
| 1149 | * needed by a given layer into cl_io.ci_lockset. |
| 1150 | * |
| 1151 | * - once locks for all layers were collected, they are sorted to avoid |
| 1152 | * dead-locks (cl_io_locks_sort()), and enqueued. |
| 1153 | * |
| 1154 | * - when all locks are acquired, IO is performed; |
| 1155 | * |
Bobi Jam | 71a96a0 | 2016-03-30 19:48:41 -0400 | [diff] [blame] | 1156 | * - locks are released after IO is complete. |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1157 | * |
| 1158 | * Striping introduces major additional complexity into locking. The |
| 1159 | * fundamental problem is that it is generally unsafe to actively use (hold) |
| 1160 | * two locks on the different OST servers at the same time, as this introduces |
| 1161 | * inter-server dependency and can lead to cascading evictions. |
| 1162 | * |
| 1163 | * Basic solution is to sub-divide large read/write IOs into smaller pieces so |
| 1164 | * that no multi-stripe locks are taken (note that this design abandons POSIX |
| 1165 | * read/write semantics). Such pieces ideally can be executed concurrently. At |
| 1166 | * the same time, certain types of IO cannot be sub-divived, without |
| 1167 | * sacrificing correctness. This includes: |
| 1168 | * |
| 1169 | * - O_APPEND write, where [0, EOF] lock has to be taken, to guarantee |
| 1170 | * atomicity; |
| 1171 | * |
| 1172 | * - ftruncate(fd, offset), where [offset, EOF] lock has to be taken. |
| 1173 | * |
| 1174 | * Also, in the case of read(fd, buf, count) or write(fd, buf, count), where |
| 1175 | * buf is a part of memory mapped Lustre file, a lock or locks protecting buf |
| 1176 | * has to be held together with the usual lock on [offset, offset + count]. |
| 1177 | * |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1178 | * Interaction with DLM |
| 1179 | * |
| 1180 | * In the expected setup, cl_lock is ultimately backed up by a collection of |
| 1181 | * DLM locks (struct ldlm_lock). Association between cl_lock and DLM lock is |
| 1182 | * implemented in osc layer, that also matches DLM events (ASTs, cancellation, |
| 1183 | * etc.) into cl_lock_operation calls. See struct osc_lock for a more detailed |
| 1184 | * description of interaction with DLM. |
| 1185 | */ |
| 1186 | |
| 1187 | /** |
| 1188 | * Lock description. |
| 1189 | */ |
| 1190 | struct cl_lock_descr { |
| 1191 | /** Object this lock is granted for. */ |
| 1192 | struct cl_object *cld_obj; |
| 1193 | /** Index of the first page protected by this lock. */ |
| 1194 | pgoff_t cld_start; |
| 1195 | /** Index of the last page (inclusive) protected by this lock. */ |
| 1196 | pgoff_t cld_end; |
| 1197 | /** Group ID, for group lock */ |
| 1198 | __u64 cld_gid; |
| 1199 | /** Lock mode. */ |
| 1200 | enum cl_lock_mode cld_mode; |
| 1201 | /** |
| 1202 | * flags to enqueue lock. A combination of bit-flags from |
| 1203 | * enum cl_enq_flags. |
| 1204 | */ |
| 1205 | __u32 cld_enq_flags; |
| 1206 | }; |
| 1207 | |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1208 | #define DDESCR "%s(%d):[%lu, %lu]:%x" |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1209 | #define PDESCR(descr) \ |
| 1210 | cl_lock_mode_name((descr)->cld_mode), (descr)->cld_mode, \ |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1211 | (descr)->cld_start, (descr)->cld_end, (descr)->cld_enq_flags |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1212 | |
| 1213 | const char *cl_lock_mode_name(const enum cl_lock_mode mode); |
| 1214 | |
| 1215 | /** |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1216 | * Layered client lock. |
| 1217 | */ |
| 1218 | struct cl_lock { |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1219 | /** List of slices. Immutable after creation. */ |
| 1220 | struct list_head cll_layers; |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1221 | /** lock attribute, extent, cl_object, etc. */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1222 | struct cl_lock_descr cll_descr; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1223 | }; |
| 1224 | |
| 1225 | /** |
| 1226 | * Per-layer part of cl_lock |
| 1227 | * |
John L. Hammond | 4a4eee0 | 2016-03-30 19:48:49 -0400 | [diff] [blame] | 1228 | * \see vvp_lock, lov_lock, lovsub_lock, osc_lock |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1229 | */ |
| 1230 | struct cl_lock_slice { |
| 1231 | struct cl_lock *cls_lock; |
| 1232 | /** Object slice corresponding to this lock slice. Immutable after |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 1233 | * creation. |
| 1234 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1235 | struct cl_object *cls_obj; |
| 1236 | const struct cl_lock_operations *cls_ops; |
| 1237 | /** Linkage into cl_lock::cll_layers. Immutable after creation. */ |
| 1238 | struct list_head cls_linkage; |
| 1239 | }; |
| 1240 | |
| 1241 | /** |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1242 | * |
| 1243 | * \see vvp_lock_ops, lov_lock_ops, lovsub_lock_ops, osc_lock_ops |
| 1244 | */ |
| 1245 | struct cl_lock_operations { |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1246 | /** @{ */ |
| 1247 | /** |
| 1248 | * Attempts to enqueue the lock. Called top-to-bottom. |
| 1249 | * |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1250 | * \retval 0 this layer has enqueued the lock successfully |
| 1251 | * \retval >0 this layer has enqueued the lock, but need to wait on |
| 1252 | * @anchor for resources |
| 1253 | * \retval -ve failure |
| 1254 | * |
John L. Hammond | 4a4eee0 | 2016-03-30 19:48:49 -0400 | [diff] [blame] | 1255 | * \see vvp_lock_enqueue(), lov_lock_enqueue(), lovsub_lock_enqueue(), |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1256 | * \see osc_lock_enqueue() |
| 1257 | */ |
| 1258 | int (*clo_enqueue)(const struct lu_env *env, |
| 1259 | const struct cl_lock_slice *slice, |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1260 | struct cl_io *io, struct cl_sync_io *anchor); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1261 | /** |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1262 | * Cancel a lock, release its DLM lock ref, while does not cancel the |
| 1263 | * DLM lock |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1264 | */ |
| 1265 | void (*clo_cancel)(const struct lu_env *env, |
| 1266 | const struct cl_lock_slice *slice); |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1267 | /** @} */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1268 | /** |
| 1269 | * Destructor. Frees resources and the slice. |
| 1270 | * |
John L. Hammond | 4a4eee0 | 2016-03-30 19:48:49 -0400 | [diff] [blame] | 1271 | * \see vvp_lock_fini(), lov_lock_fini(), lovsub_lock_fini(), |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1272 | * \see osc_lock_fini() |
| 1273 | */ |
| 1274 | void (*clo_fini)(const struct lu_env *env, struct cl_lock_slice *slice); |
| 1275 | /** |
| 1276 | * Optional debugging helper. Prints given lock slice. |
| 1277 | */ |
| 1278 | int (*clo_print)(const struct lu_env *env, |
| 1279 | void *cookie, lu_printer_t p, |
| 1280 | const struct cl_lock_slice *slice); |
| 1281 | }; |
| 1282 | |
| 1283 | #define CL_LOCK_DEBUG(mask, env, lock, format, ...) \ |
| 1284 | do { \ |
| 1285 | LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, mask, NULL); \ |
| 1286 | \ |
| 1287 | if (cfs_cdebug_show(mask, DEBUG_SUBSYSTEM)) { \ |
| 1288 | cl_lock_print(env, &msgdata, lu_cdebug_printer, lock); \ |
Mike Rapoport | b2952d6 | 2015-09-03 11:49:13 +0300 | [diff] [blame] | 1289 | CDEBUG(mask, format, ## __VA_ARGS__); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1290 | } \ |
| 1291 | } while (0) |
| 1292 | |
| 1293 | #define CL_LOCK_ASSERT(expr, env, lock) do { \ |
| 1294 | if (likely(expr)) \ |
| 1295 | break; \ |
| 1296 | \ |
| 1297 | CL_LOCK_DEBUG(D_ERROR, env, lock, "failed at %s.\n", #expr); \ |
| 1298 | LBUG(); \ |
| 1299 | } while (0) |
| 1300 | |
| 1301 | /** @} cl_lock */ |
| 1302 | |
| 1303 | /** \addtogroup cl_page_list cl_page_list |
| 1304 | * Page list used to perform collective operations on a group of pages. |
| 1305 | * |
| 1306 | * Pages are added to the list one by one. cl_page_list acquires a reference |
| 1307 | * for every page in it. Page list is used to perform collective operations on |
| 1308 | * pages: |
| 1309 | * |
| 1310 | * - submit pages for an immediate transfer, |
| 1311 | * |
| 1312 | * - own pages on behalf of certain io (waiting for each page in turn), |
| 1313 | * |
| 1314 | * - discard pages. |
| 1315 | * |
| 1316 | * When list is finalized, it releases references on all pages it still has. |
| 1317 | * |
| 1318 | * \todo XXX concurrency control. |
| 1319 | * |
| 1320 | * @{ |
| 1321 | */ |
| 1322 | struct cl_page_list { |
| 1323 | unsigned pl_nr; |
| 1324 | struct list_head pl_pages; |
Greg Kroah-Hartman | 68b636b | 2013-08-04 08:56:42 +0800 | [diff] [blame] | 1325 | struct task_struct *pl_owner; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1326 | }; |
| 1327 | |
| 1328 | /** |
| 1329 | * A 2-queue of pages. A convenience data-type for common use case, 2-queue |
| 1330 | * contains an incoming page list and an outgoing page list. |
| 1331 | */ |
| 1332 | struct cl_2queue { |
| 1333 | struct cl_page_list c2_qin; |
| 1334 | struct cl_page_list c2_qout; |
| 1335 | }; |
| 1336 | |
| 1337 | /** @} cl_page_list */ |
| 1338 | |
| 1339 | /** \addtogroup cl_io cl_io |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 1340 | * @{ |
| 1341 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1342 | /** \struct cl_io |
| 1343 | * I/O |
| 1344 | * |
| 1345 | * cl_io represents a high level I/O activity like |
| 1346 | * read(2)/write(2)/truncate(2) system call, or cancellation of an extent |
| 1347 | * lock. |
| 1348 | * |
| 1349 | * cl_io is a layered object, much like cl_{object,page,lock} but with one |
| 1350 | * important distinction. We want to minimize number of calls to the allocator |
| 1351 | * in the fast path, e.g., in the case of read(2) when everything is cached: |
| 1352 | * client already owns the lock over region being read, and data are cached |
| 1353 | * due to read-ahead. To avoid allocation of cl_io layers in such situations, |
| 1354 | * per-layer io state is stored in the session, associated with the io, see |
| 1355 | * struct {vvp,lov,osc}_io for example. Sessions allocation is amortized |
| 1356 | * by using free-lists, see cl_env_get(). |
| 1357 | * |
| 1358 | * There is a small predefined number of possible io types, enumerated in enum |
| 1359 | * cl_io_type. |
| 1360 | * |
| 1361 | * cl_io is a state machine, that can be advanced concurrently by the multiple |
| 1362 | * threads. It is up to these threads to control the concurrency and, |
| 1363 | * specifically, to detect when io is done, and its state can be safely |
| 1364 | * released. |
| 1365 | * |
| 1366 | * For read/write io overall execution plan is as following: |
| 1367 | * |
| 1368 | * (0) initialize io state through all layers; |
| 1369 | * |
| 1370 | * (1) loop: prepare chunk of work to do |
| 1371 | * |
| 1372 | * (2) call all layers to collect locks they need to process current chunk |
| 1373 | * |
| 1374 | * (3) sort all locks to avoid dead-locks, and acquire them |
| 1375 | * |
| 1376 | * (4) process the chunk: call per-page methods |
| 1377 | * (cl_io_operations::cio_read_page() for read, |
| 1378 | * cl_io_operations::cio_prepare_write(), |
| 1379 | * cl_io_operations::cio_commit_write() for write) |
| 1380 | * |
| 1381 | * (5) release locks |
| 1382 | * |
| 1383 | * (6) repeat loop. |
| 1384 | * |
| 1385 | * To implement the "parallel IO mode", lov layer creates sub-io's (lazily to |
| 1386 | * address allocation efficiency issues mentioned above), and returns with the |
| 1387 | * special error condition from per-page method when current sub-io has to |
| 1388 | * block. This causes io loop to be repeated, and lov switches to the next |
| 1389 | * sub-io in its cl_io_operations::cio_iter_init() implementation. |
| 1390 | */ |
| 1391 | |
| 1392 | /** IO types */ |
| 1393 | enum cl_io_type { |
| 1394 | /** read system call */ |
| 1395 | CIT_READ, |
| 1396 | /** write system call */ |
| 1397 | CIT_WRITE, |
| 1398 | /** truncate, utime system calls */ |
| 1399 | CIT_SETATTR, |
| 1400 | /** |
| 1401 | * page fault handling |
| 1402 | */ |
| 1403 | CIT_FAULT, |
| 1404 | /** |
| 1405 | * fsync system call handling |
| 1406 | * To write out a range of file |
| 1407 | */ |
| 1408 | CIT_FSYNC, |
| 1409 | /** |
| 1410 | * Miscellaneous io. This is used for occasional io activity that |
| 1411 | * doesn't fit into other types. Currently this is used for: |
| 1412 | * |
| 1413 | * - cancellation of an extent lock. This io exists as a context |
| 1414 | * to write dirty pages from under the lock being canceled back |
| 1415 | * to the server; |
| 1416 | * |
| 1417 | * - VM induced page write-out. An io context for writing page out |
| 1418 | * for memory cleansing; |
| 1419 | * |
| 1420 | * - glimpse. An io context to acquire glimpse lock. |
| 1421 | * |
| 1422 | * - grouplock. An io context to acquire group lock. |
| 1423 | * |
| 1424 | * CIT_MISC io is used simply as a context in which locks and pages |
| 1425 | * are manipulated. Such io has no internal "process", that is, |
| 1426 | * cl_io_loop() is never called for it. |
| 1427 | */ |
| 1428 | CIT_MISC, |
| 1429 | CIT_OP_NR |
| 1430 | }; |
| 1431 | |
| 1432 | /** |
| 1433 | * States of cl_io state machine |
| 1434 | */ |
| 1435 | enum cl_io_state { |
| 1436 | /** Not initialized. */ |
| 1437 | CIS_ZERO, |
| 1438 | /** Initialized. */ |
| 1439 | CIS_INIT, |
| 1440 | /** IO iteration started. */ |
| 1441 | CIS_IT_STARTED, |
| 1442 | /** Locks taken. */ |
| 1443 | CIS_LOCKED, |
| 1444 | /** Actual IO is in progress. */ |
| 1445 | CIS_IO_GOING, |
| 1446 | /** IO for the current iteration finished. */ |
| 1447 | CIS_IO_FINISHED, |
| 1448 | /** Locks released. */ |
| 1449 | CIS_UNLOCKED, |
| 1450 | /** Iteration completed. */ |
| 1451 | CIS_IT_ENDED, |
| 1452 | /** cl_io finalized. */ |
| 1453 | CIS_FINI |
| 1454 | }; |
| 1455 | |
| 1456 | /** |
| 1457 | * IO state private for a layer. |
| 1458 | * |
| 1459 | * This is usually embedded into layer session data, rather than allocated |
| 1460 | * dynamically. |
| 1461 | * |
John L. Hammond | 10cdef7 | 2016-03-30 19:48:51 -0400 | [diff] [blame] | 1462 | * \see vvp_io, lov_io, osc_io |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1463 | */ |
| 1464 | struct cl_io_slice { |
| 1465 | struct cl_io *cis_io; |
| 1466 | /** corresponding object slice. Immutable after creation. */ |
| 1467 | struct cl_object *cis_obj; |
| 1468 | /** io operations. Immutable after creation. */ |
| 1469 | const struct cl_io_operations *cis_iop; |
| 1470 | /** |
| 1471 | * linkage into a list of all slices for a given cl_io, hanging off |
| 1472 | * cl_io::ci_layers. Immutable after creation. |
| 1473 | */ |
| 1474 | struct list_head cis_linkage; |
| 1475 | }; |
| 1476 | |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 1477 | typedef void (*cl_commit_cbt)(const struct lu_env *, struct cl_io *, |
| 1478 | struct cl_page *); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1479 | /** |
| 1480 | * Per-layer io operations. |
| 1481 | * \see vvp_io_ops, lov_io_ops, lovsub_io_ops, osc_io_ops |
| 1482 | */ |
| 1483 | struct cl_io_operations { |
| 1484 | /** |
| 1485 | * Vector of io state transition methods for every io type. |
| 1486 | * |
| 1487 | * \see cl_page_operations::io |
| 1488 | */ |
| 1489 | struct { |
| 1490 | /** |
| 1491 | * Prepare io iteration at a given layer. |
| 1492 | * |
| 1493 | * Called top-to-bottom at the beginning of each iteration of |
| 1494 | * "io loop" (if it makes sense for this type of io). Here |
| 1495 | * layer selects what work it will do during this iteration. |
| 1496 | * |
| 1497 | * \see cl_io_operations::cio_iter_fini() |
| 1498 | */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 1499 | int (*cio_iter_init)(const struct lu_env *env, |
| 1500 | const struct cl_io_slice *slice); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1501 | /** |
| 1502 | * Finalize io iteration. |
| 1503 | * |
| 1504 | * Called bottom-to-top at the end of each iteration of "io |
| 1505 | * loop". Here layers can decide whether IO has to be |
| 1506 | * continued. |
| 1507 | * |
| 1508 | * \see cl_io_operations::cio_iter_init() |
| 1509 | */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 1510 | void (*cio_iter_fini)(const struct lu_env *env, |
| 1511 | const struct cl_io_slice *slice); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1512 | /** |
| 1513 | * Collect locks for the current iteration of io. |
| 1514 | * |
| 1515 | * Called top-to-bottom to collect all locks necessary for |
| 1516 | * this iteration. This methods shouldn't actually enqueue |
| 1517 | * anything, instead it should post a lock through |
| 1518 | * cl_io_lock_add(). Once all locks are collected, they are |
| 1519 | * sorted and enqueued in the proper order. |
| 1520 | */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 1521 | int (*cio_lock)(const struct lu_env *env, |
| 1522 | const struct cl_io_slice *slice); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1523 | /** |
| 1524 | * Finalize unlocking. |
| 1525 | * |
| 1526 | * Called bottom-to-top to finish layer specific unlocking |
| 1527 | * functionality, after generic code released all locks |
| 1528 | * acquired by cl_io_operations::cio_lock(). |
| 1529 | */ |
| 1530 | void (*cio_unlock)(const struct lu_env *env, |
| 1531 | const struct cl_io_slice *slice); |
| 1532 | /** |
| 1533 | * Start io iteration. |
| 1534 | * |
| 1535 | * Once all locks are acquired, called top-to-bottom to |
| 1536 | * commence actual IO. In the current implementation, |
| 1537 | * top-level vvp_io_{read,write}_start() does all the work |
| 1538 | * synchronously by calling generic_file_*(), so other layers |
| 1539 | * are called when everything is done. |
| 1540 | */ |
| 1541 | int (*cio_start)(const struct lu_env *env, |
| 1542 | const struct cl_io_slice *slice); |
| 1543 | /** |
| 1544 | * Called top-to-bottom at the end of io loop. Here layer |
| 1545 | * might wait for an unfinished asynchronous io. |
| 1546 | */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 1547 | void (*cio_end)(const struct lu_env *env, |
| 1548 | const struct cl_io_slice *slice); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1549 | /** |
| 1550 | * Called bottom-to-top to notify layers that read/write IO |
| 1551 | * iteration finished, with \a nob bytes transferred. |
| 1552 | */ |
| 1553 | void (*cio_advance)(const struct lu_env *env, |
| 1554 | const struct cl_io_slice *slice, |
| 1555 | size_t nob); |
| 1556 | /** |
| 1557 | * Called once per io, bottom-to-top to release io resources. |
| 1558 | */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 1559 | void (*cio_fini)(const struct lu_env *env, |
| 1560 | const struct cl_io_slice *slice); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1561 | } op[CIT_OP_NR]; |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 1562 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1563 | /** |
| 1564 | * Submit pages from \a queue->c2_qin for IO, and move |
| 1565 | * successfully submitted pages into \a queue->c2_qout. Return |
| 1566 | * non-zero if failed to submit even the single page. If |
| 1567 | * submission failed after some pages were moved into \a |
| 1568 | * queue->c2_qout, completion callback with non-zero ioret is |
| 1569 | * executed on them. |
| 1570 | */ |
| 1571 | int (*cio_submit)(const struct lu_env *env, |
| 1572 | const struct cl_io_slice *slice, |
| 1573 | enum cl_req_type crt, |
| 1574 | struct cl_2queue *queue); |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 1575 | /** |
| 1576 | * Queue async page for write. |
| 1577 | * The difference between cio_submit and cio_queue is that |
| 1578 | * cio_submit is for urgent request. |
| 1579 | */ |
| 1580 | int (*cio_commit_async)(const struct lu_env *env, |
| 1581 | const struct cl_io_slice *slice, |
| 1582 | struct cl_page_list *queue, int from, int to, |
| 1583 | cl_commit_cbt cb); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1584 | /** |
| 1585 | * Read missing page. |
| 1586 | * |
| 1587 | * Called by a top-level cl_io_operations::op[CIT_READ]::cio_start() |
| 1588 | * method, when it hits not-up-to-date page in the range. Optional. |
| 1589 | * |
| 1590 | * \pre io->ci_type == CIT_READ |
| 1591 | */ |
| 1592 | int (*cio_read_page)(const struct lu_env *env, |
| 1593 | const struct cl_io_slice *slice, |
| 1594 | const struct cl_page_slice *page); |
| 1595 | /** |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1596 | * Optional debugging helper. Print given io slice. |
| 1597 | */ |
| 1598 | int (*cio_print)(const struct lu_env *env, void *cookie, |
| 1599 | lu_printer_t p, const struct cl_io_slice *slice); |
| 1600 | }; |
| 1601 | |
| 1602 | /** |
| 1603 | * Flags to lock enqueue procedure. |
| 1604 | * \ingroup cl_lock |
| 1605 | */ |
| 1606 | enum cl_enq_flags { |
| 1607 | /** |
| 1608 | * instruct server to not block, if conflicting lock is found. Instead |
| 1609 | * -EWOULDBLOCK is returned immediately. |
| 1610 | */ |
| 1611 | CEF_NONBLOCK = 0x00000001, |
| 1612 | /** |
| 1613 | * take lock asynchronously (out of order), as it cannot |
| 1614 | * deadlock. This is for LDLM_FL_HAS_INTENT locks used for glimpsing. |
| 1615 | */ |
| 1616 | CEF_ASYNC = 0x00000002, |
| 1617 | /** |
| 1618 | * tell the server to instruct (though a flag in the blocking ast) an |
| 1619 | * owner of the conflicting lock, that it can drop dirty pages |
| 1620 | * protected by this lock, without sending them to the server. |
| 1621 | */ |
| 1622 | CEF_DISCARD_DATA = 0x00000004, |
| 1623 | /** |
| 1624 | * tell the sub layers that it must be a `real' lock. This is used for |
| 1625 | * mmapped-buffer locks and glimpse locks that must be never converted |
| 1626 | * into lockless mode. |
| 1627 | * |
| 1628 | * \see vvp_mmap_locks(), cl_glimpse_lock(). |
| 1629 | */ |
| 1630 | CEF_MUST = 0x00000008, |
| 1631 | /** |
| 1632 | * tell the sub layers that never request a `real' lock. This flag is |
| 1633 | * not used currently. |
| 1634 | * |
| 1635 | * cl_io::ci_lockreq and CEF_{MUST,NEVER} flags specify lockless |
| 1636 | * conversion policy: ci_lockreq describes generic information of lock |
| 1637 | * requirement for this IO, especially for locks which belong to the |
| 1638 | * object doing IO; however, lock itself may have precise requirements |
| 1639 | * that are described by the enqueue flags. |
| 1640 | */ |
| 1641 | CEF_NEVER = 0x00000010, |
| 1642 | /** |
| 1643 | * for async glimpse lock. |
| 1644 | */ |
| 1645 | CEF_AGL = 0x00000020, |
| 1646 | /** |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1647 | * enqueue a lock to test DLM lock existence. |
| 1648 | */ |
| 1649 | CEF_PEEK = 0x00000040, |
| 1650 | /** |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1651 | * mask of enq_flags. |
| 1652 | */ |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1653 | CEF_MASK = 0x0000007f, |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1654 | }; |
| 1655 | |
| 1656 | /** |
| 1657 | * Link between lock and io. Intermediate structure is needed, because the |
| 1658 | * same lock can be part of multiple io's simultaneously. |
| 1659 | */ |
| 1660 | struct cl_io_lock_link { |
| 1661 | /** linkage into one of cl_lockset lists. */ |
| 1662 | struct list_head cill_linkage; |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1663 | struct cl_lock cill_lock; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1664 | /** optional destructor */ |
| 1665 | void (*cill_fini)(const struct lu_env *env, |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 1666 | struct cl_io_lock_link *link); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1667 | }; |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 1668 | #define cill_descr cill_lock.cll_descr |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1669 | |
| 1670 | /** |
| 1671 | * Lock-set represents a collection of locks, that io needs at a |
| 1672 | * time. Generally speaking, client tries to avoid holding multiple locks when |
| 1673 | * possible, because |
| 1674 | * |
| 1675 | * - holding extent locks over multiple ost's introduces the danger of |
| 1676 | * "cascading timeouts"; |
| 1677 | * |
| 1678 | * - holding multiple locks over the same ost is still dead-lock prone, |
| 1679 | * see comment in osc_lock_enqueue(), |
| 1680 | * |
| 1681 | * but there are certain situations where this is unavoidable: |
| 1682 | * |
| 1683 | * - O_APPEND writes have to take [0, EOF] lock for correctness; |
| 1684 | * |
| 1685 | * - truncate has to take [new-size, EOF] lock for correctness; |
| 1686 | * |
| 1687 | * - SNS has to take locks across full stripe for correctness; |
| 1688 | * |
| 1689 | * - in the case when user level buffer, supplied to {read,write}(file0), |
| 1690 | * is a part of a memory mapped lustre file, client has to take a dlm |
| 1691 | * locks on file0, and all files that back up the buffer (or a part of |
| 1692 | * the buffer, that is being processed in the current chunk, in any |
| 1693 | * case, there are situations where at least 2 locks are necessary). |
| 1694 | * |
| 1695 | * In such cases we at least try to take locks in the same consistent |
| 1696 | * order. To this end, all locks are first collected, then sorted, and then |
| 1697 | * enqueued. |
| 1698 | */ |
| 1699 | struct cl_lockset { |
| 1700 | /** locks to be acquired. */ |
| 1701 | struct list_head cls_todo; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1702 | /** locks acquired. */ |
| 1703 | struct list_head cls_done; |
| 1704 | }; |
| 1705 | |
| 1706 | /** |
| 1707 | * Lock requirements(demand) for IO. It should be cl_io_lock_req, |
| 1708 | * but 'req' is always to be thought as 'request' :-) |
| 1709 | */ |
| 1710 | enum cl_io_lock_dmd { |
| 1711 | /** Always lock data (e.g., O_APPEND). */ |
| 1712 | CILR_MANDATORY = 0, |
| 1713 | /** Layers are free to decide between local and global locking. */ |
| 1714 | CILR_MAYBE, |
Oleg Drokin | 85f552d | 2016-02-26 01:49:56 -0500 | [diff] [blame] | 1715 | /** Never lock: there is no cache (e.g., lockless IO). */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1716 | CILR_NEVER |
| 1717 | }; |
| 1718 | |
| 1719 | enum cl_fsync_mode { |
| 1720 | /** start writeback, do not wait for them to finish */ |
| 1721 | CL_FSYNC_NONE = 0, |
| 1722 | /** start writeback and wait for them to finish */ |
| 1723 | CL_FSYNC_LOCAL = 1, |
| 1724 | /** discard all of dirty pages in a specific file range */ |
| 1725 | CL_FSYNC_DISCARD = 2, |
| 1726 | /** start writeback and make sure they have reached storage before |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 1727 | * return. OST_SYNC RPC must be issued and finished |
| 1728 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1729 | CL_FSYNC_ALL = 3 |
| 1730 | }; |
| 1731 | |
| 1732 | struct cl_io_rw_common { |
| 1733 | loff_t crw_pos; |
| 1734 | size_t crw_count; |
| 1735 | int crw_nonblock; |
| 1736 | }; |
| 1737 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1738 | /** |
| 1739 | * State for io. |
| 1740 | * |
| 1741 | * cl_io is shared by all threads participating in this IO (in current |
| 1742 | * implementation only one thread advances IO, but parallel IO design and |
| 1743 | * concurrent copy_*_user() require multiple threads acting on the same IO. It |
| 1744 | * is up to these threads to serialize their activities, including updates to |
| 1745 | * mutable cl_io fields. |
| 1746 | */ |
| 1747 | struct cl_io { |
| 1748 | /** type of this IO. Immutable after creation. */ |
| 1749 | enum cl_io_type ci_type; |
| 1750 | /** current state of cl_io state machine. */ |
| 1751 | enum cl_io_state ci_state; |
| 1752 | /** main object this io is against. Immutable after creation. */ |
| 1753 | struct cl_object *ci_obj; |
| 1754 | /** |
| 1755 | * Upper layer io, of which this io is a part of. Immutable after |
| 1756 | * creation. |
| 1757 | */ |
| 1758 | struct cl_io *ci_parent; |
| 1759 | /** List of slices. Immutable after creation. */ |
| 1760 | struct list_head ci_layers; |
| 1761 | /** list of locks (to be) acquired by this io. */ |
| 1762 | struct cl_lockset ci_lockset; |
| 1763 | /** lock requirements, this is just a help info for sublayers. */ |
| 1764 | enum cl_io_lock_dmd ci_lockreq; |
| 1765 | union { |
| 1766 | struct cl_rd_io { |
| 1767 | struct cl_io_rw_common rd; |
| 1768 | } ci_rd; |
| 1769 | struct cl_wr_io { |
| 1770 | struct cl_io_rw_common wr; |
| 1771 | int wr_append; |
| 1772 | int wr_sync; |
| 1773 | } ci_wr; |
| 1774 | struct cl_io_rw_common ci_rw; |
| 1775 | struct cl_setattr_io { |
| 1776 | struct ost_lvb sa_attr; |
| 1777 | unsigned int sa_valid; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1778 | } ci_setattr; |
| 1779 | struct cl_fault_io { |
| 1780 | /** page index within file. */ |
| 1781 | pgoff_t ft_index; |
| 1782 | /** bytes valid byte on a faulted page. */ |
| 1783 | int ft_nob; |
| 1784 | /** writable page? for nopage() only */ |
| 1785 | int ft_writable; |
| 1786 | /** page of an executable? */ |
| 1787 | int ft_executable; |
| 1788 | /** page_mkwrite() */ |
| 1789 | int ft_mkwrite; |
| 1790 | /** resulting page */ |
| 1791 | struct cl_page *ft_page; |
| 1792 | } ci_fault; |
| 1793 | struct cl_fsync_io { |
| 1794 | loff_t fi_start; |
| 1795 | loff_t fi_end; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1796 | /** file system level fid */ |
| 1797 | struct lu_fid *fi_fid; |
| 1798 | enum cl_fsync_mode fi_mode; |
| 1799 | /* how many pages were written/discarded */ |
| 1800 | unsigned int fi_nr_written; |
| 1801 | } ci_fsync; |
| 1802 | } u; |
| 1803 | struct cl_2queue ci_queue; |
| 1804 | size_t ci_nob; |
| 1805 | int ci_result; |
| 1806 | unsigned int ci_continue:1, |
| 1807 | /** |
| 1808 | * This io has held grouplock, to inform sublayers that |
| 1809 | * don't do lockless i/o. |
| 1810 | */ |
| 1811 | ci_no_srvlock:1, |
| 1812 | /** |
| 1813 | * The whole IO need to be restarted because layout has been changed |
| 1814 | */ |
| 1815 | ci_need_restart:1, |
| 1816 | /** |
| 1817 | * to not refresh layout - the IO issuer knows that the layout won't |
| 1818 | * change(page operations, layout change causes all page to be |
| 1819 | * discarded), or it doesn't matter if it changes(sync). |
| 1820 | */ |
| 1821 | ci_ignore_layout:1, |
| 1822 | /** |
| 1823 | * Check if layout changed after the IO finishes. Mainly for HSM |
| 1824 | * requirement. If IO occurs to openning files, it doesn't need to |
| 1825 | * verify layout because HSM won't release openning files. |
Masanari Iida | bd9070c | 2014-03-08 22:58:34 +0900 | [diff] [blame] | 1826 | * Right now, only two operations need to verify layout: glimpse |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1827 | * and setattr. |
| 1828 | */ |
JC Lafoucriere | 5ea17d6 | 2013-11-21 22:24:48 +0800 | [diff] [blame] | 1829 | ci_verify_layout:1, |
| 1830 | /** |
| 1831 | * file is released, restore has to to be triggered by vvp layer |
| 1832 | */ |
John L. Hammond | ec9bca9 | 2014-02-28 21:16:35 -0500 | [diff] [blame] | 1833 | ci_restore_needed:1, |
| 1834 | /** |
| 1835 | * O_NOATIME |
| 1836 | */ |
| 1837 | ci_noatime:1; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1838 | /** |
| 1839 | * Number of pages owned by this IO. For invariant checking. |
| 1840 | */ |
| 1841 | unsigned ci_owned_nr; |
| 1842 | }; |
| 1843 | |
| 1844 | /** @} cl_io */ |
| 1845 | |
| 1846 | /** \addtogroup cl_req cl_req |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 1847 | * @{ |
| 1848 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1849 | /** \struct cl_req |
| 1850 | * Transfer. |
| 1851 | * |
| 1852 | * There are two possible modes of transfer initiation on the client: |
| 1853 | * |
| 1854 | * - immediate transfer: this is started when a high level io wants a page |
| 1855 | * or a collection of pages to be transferred right away. Examples: |
| 1856 | * read-ahead, synchronous read in the case of non-page aligned write, |
| 1857 | * page write-out as a part of extent lock cancellation, page write-out |
| 1858 | * as a part of memory cleansing. Immediate transfer can be both |
| 1859 | * cl_req_type::CRT_READ and cl_req_type::CRT_WRITE; |
| 1860 | * |
| 1861 | * - opportunistic transfer (cl_req_type::CRT_WRITE only), that happens |
| 1862 | * when io wants to transfer a page to the server some time later, when |
| 1863 | * it can be done efficiently. Example: pages dirtied by the write(2) |
| 1864 | * path. |
| 1865 | * |
| 1866 | * In any case, transfer takes place in the form of a cl_req, which is a |
| 1867 | * representation for a network RPC. |
| 1868 | * |
| 1869 | * Pages queued for an opportunistic transfer are cached until it is decided |
| 1870 | * that efficient RPC can be composed of them. This decision is made by "a |
| 1871 | * req-formation engine", currently implemented as a part of osc |
| 1872 | * layer. Req-formation depends on many factors: the size of the resulting |
| 1873 | * RPC, whether or not multi-object RPCs are supported by the server, |
| 1874 | * max-rpc-in-flight limitations, size of the dirty cache, etc. |
| 1875 | * |
| 1876 | * For the immediate transfer io submits a cl_page_list, that req-formation |
| 1877 | * engine slices into cl_req's, possibly adding cached pages to some of |
| 1878 | * the resulting req's. |
| 1879 | * |
| 1880 | * Whenever a page from cl_page_list is added to a newly constructed req, its |
| 1881 | * cl_page_operations::cpo_prep() layer methods are called. At that moment, |
| 1882 | * page state is atomically changed from cl_page_state::CPS_OWNED to |
| 1883 | * cl_page_state::CPS_PAGEOUT or cl_page_state::CPS_PAGEIN, cl_page::cp_owner |
| 1884 | * is zeroed, and cl_page::cp_req is set to the |
| 1885 | * req. cl_page_operations::cpo_prep() method at the particular layer might |
| 1886 | * return -EALREADY to indicate that it does not need to submit this page |
| 1887 | * at all. This is possible, for example, if page, submitted for read, |
| 1888 | * became up-to-date in the meantime; and for write, the page don't have |
| 1889 | * dirty bit marked. \see cl_io_submit_rw() |
| 1890 | * |
| 1891 | * Whenever a cached page is added to a newly constructed req, its |
| 1892 | * cl_page_operations::cpo_make_ready() layer methods are called. At that |
| 1893 | * moment, page state is atomically changed from cl_page_state::CPS_CACHED to |
| 1894 | * cl_page_state::CPS_PAGEOUT, and cl_page::cp_req is set to |
| 1895 | * req. cl_page_operations::cpo_make_ready() method at the particular layer |
| 1896 | * might return -EAGAIN to indicate that this page is not eligible for the |
| 1897 | * transfer right now. |
| 1898 | * |
| 1899 | * FUTURE |
| 1900 | * |
| 1901 | * Plan is to divide transfers into "priority bands" (indicated when |
| 1902 | * submitting cl_page_list, and queuing a page for the opportunistic transfer) |
| 1903 | * and allow glueing of cached pages to immediate transfers only within single |
| 1904 | * band. This would make high priority transfers (like lock cancellation or |
| 1905 | * memory pressure induced write-out) really high priority. |
| 1906 | * |
| 1907 | */ |
| 1908 | |
| 1909 | /** |
| 1910 | * Per-transfer attributes. |
| 1911 | */ |
| 1912 | struct cl_req_attr { |
| 1913 | /** Generic attributes for the server consumption. */ |
| 1914 | struct obdo *cra_oa; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1915 | /** Jobid */ |
| 1916 | char cra_jobid[JOBSTATS_JOBID_SIZE]; |
| 1917 | }; |
| 1918 | |
| 1919 | /** |
| 1920 | * Transfer request operations definable at every layer. |
| 1921 | * |
| 1922 | * Concurrency: transfer formation engine synchronizes calls to all transfer |
| 1923 | * methods. |
| 1924 | */ |
| 1925 | struct cl_req_operations { |
| 1926 | /** |
| 1927 | * Invoked top-to-bottom by cl_req_prep() when transfer formation is |
| 1928 | * complete (all pages are added). |
| 1929 | * |
| 1930 | * \see osc_req_prep() |
| 1931 | */ |
| 1932 | int (*cro_prep)(const struct lu_env *env, |
| 1933 | const struct cl_req_slice *slice); |
| 1934 | /** |
| 1935 | * Called top-to-bottom to fill in \a oa fields. This is called twice |
| 1936 | * with different flags, see bug 10150 and osc_build_req(). |
| 1937 | * |
| 1938 | * \param obj an object from cl_req which attributes are to be set in |
| 1939 | * \a oa. |
| 1940 | * |
| 1941 | * \param oa struct obdo where attributes are placed |
| 1942 | * |
| 1943 | * \param flags \a oa fields to be filled. |
| 1944 | */ |
| 1945 | void (*cro_attr_set)(const struct lu_env *env, |
| 1946 | const struct cl_req_slice *slice, |
| 1947 | const struct cl_object *obj, |
Oleg Drokin | 21aef7d | 2014-08-15 12:55:56 -0400 | [diff] [blame] | 1948 | struct cl_req_attr *attr, u64 flags); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1949 | /** |
| 1950 | * Called top-to-bottom from cl_req_completion() to notify layers that |
| 1951 | * transfer completed. Has to free all state allocated by |
| 1952 | * cl_device_operations::cdo_req_init(). |
| 1953 | */ |
| 1954 | void (*cro_completion)(const struct lu_env *env, |
| 1955 | const struct cl_req_slice *slice, int ioret); |
| 1956 | }; |
| 1957 | |
| 1958 | /** |
| 1959 | * A per-object state that (potentially multi-object) transfer request keeps. |
| 1960 | */ |
| 1961 | struct cl_req_obj { |
| 1962 | /** object itself */ |
| 1963 | struct cl_object *ro_obj; |
| 1964 | /** reference to cl_req_obj::ro_obj. For debugging. */ |
John L. Hammond | 631abc6 | 2013-07-25 01:17:30 +0800 | [diff] [blame] | 1965 | struct lu_ref_link ro_obj_ref; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1966 | /* something else? Number of pages for a given object? */ |
| 1967 | }; |
| 1968 | |
| 1969 | /** |
| 1970 | * Transfer request. |
| 1971 | * |
| 1972 | * Transfer requests are not reference counted, because IO sub-system owns |
| 1973 | * them exclusively and knows when to free them. |
| 1974 | * |
| 1975 | * Life cycle. |
| 1976 | * |
| 1977 | * cl_req is created by cl_req_alloc() that calls |
| 1978 | * cl_device_operations::cdo_req_init() device methods to allocate per-req |
| 1979 | * state in every layer. |
| 1980 | * |
| 1981 | * Then pages are added (cl_req_page_add()), req keeps track of all objects it |
| 1982 | * contains pages for. |
| 1983 | * |
| 1984 | * Once all pages were collected, cl_page_operations::cpo_prep() method is |
| 1985 | * called top-to-bottom. At that point layers can modify req, let it pass, or |
| 1986 | * deny it completely. This is to support things like SNS that have transfer |
| 1987 | * ordering requirements invisible to the individual req-formation engine. |
| 1988 | * |
| 1989 | * On transfer completion (or transfer timeout, or failure to initiate the |
| 1990 | * transfer of an allocated req), cl_req_operations::cro_completion() method |
| 1991 | * is called, after execution of cl_page_operations::cpo_completion() of all |
| 1992 | * req's pages. |
| 1993 | */ |
| 1994 | struct cl_req { |
| 1995 | enum cl_req_type crq_type; |
Masanari Iida | bd9070c | 2014-03-08 22:58:34 +0900 | [diff] [blame] | 1996 | /** A list of pages being transferred */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 1997 | struct list_head crq_pages; |
| 1998 | /** Number of pages in cl_req::crq_pages */ |
| 1999 | unsigned crq_nrpages; |
| 2000 | /** An array of objects which pages are in ->crq_pages */ |
| 2001 | struct cl_req_obj *crq_o; |
| 2002 | /** Number of elements in cl_req::crq_objs[] */ |
| 2003 | unsigned crq_nrobjs; |
| 2004 | struct list_head crq_layers; |
| 2005 | }; |
| 2006 | |
| 2007 | /** |
| 2008 | * Per-layer state for request. |
| 2009 | */ |
| 2010 | struct cl_req_slice { |
| 2011 | struct cl_req *crs_req; |
| 2012 | struct cl_device *crs_dev; |
| 2013 | struct list_head crs_linkage; |
| 2014 | const struct cl_req_operations *crs_ops; |
| 2015 | }; |
| 2016 | |
| 2017 | /* @} cl_req */ |
| 2018 | |
| 2019 | enum cache_stats_item { |
| 2020 | /** how many cache lookups were performed */ |
| 2021 | CS_lookup = 0, |
| 2022 | /** how many times cache lookup resulted in a hit */ |
| 2023 | CS_hit, |
| 2024 | /** how many entities are in the cache right now */ |
| 2025 | CS_total, |
| 2026 | /** how many entities in the cache are actively used (and cannot be |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2027 | * evicted) right now |
| 2028 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2029 | CS_busy, |
| 2030 | /** how many entities were created at all */ |
| 2031 | CS_create, |
| 2032 | CS_NR |
| 2033 | }; |
| 2034 | |
| 2035 | #define CS_NAMES { "lookup", "hit", "total", "busy", "create" } |
| 2036 | |
| 2037 | /** |
| 2038 | * Stats for a generic cache (similar to inode, lu_object, etc. caches). |
| 2039 | */ |
| 2040 | struct cache_stats { |
| 2041 | const char *cs_name; |
| 2042 | atomic_t cs_stats[CS_NR]; |
| 2043 | }; |
| 2044 | |
| 2045 | /** These are not exported so far */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2046 | void cache_stats_init(struct cache_stats *cs, const char *name); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2047 | |
| 2048 | /** |
| 2049 | * Client-side site. This represents particular client stack. "Global" |
| 2050 | * variables should (directly or indirectly) be added here to allow multiple |
| 2051 | * clients to co-exist in the single address space. |
| 2052 | */ |
| 2053 | struct cl_site { |
| 2054 | struct lu_site cs_lu; |
| 2055 | /** |
| 2056 | * Statistical counters. Atomics do not scale, something better like |
| 2057 | * per-cpu counters is needed. |
| 2058 | * |
Oleg Drokin | 406c1c7 | 2016-02-16 00:46:34 -0500 | [diff] [blame] | 2059 | * These are exported as /sys/kernel/debug/lustre/llite/.../site |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2060 | * |
| 2061 | * When interpreting keep in mind that both sub-locks (and sub-pages) |
| 2062 | * and top-locks (and top-pages) are accounted here. |
| 2063 | */ |
| 2064 | struct cache_stats cs_pages; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2065 | atomic_t cs_pages_state[CPS_NR]; |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2066 | }; |
| 2067 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2068 | int cl_site_init(struct cl_site *s, struct cl_device *top); |
| 2069 | void cl_site_fini(struct cl_site *s); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2070 | void cl_stack_fini(const struct lu_env *env, struct cl_device *cl); |
| 2071 | |
| 2072 | /** |
| 2073 | * Output client site statistical counters into a buffer. Suitable for |
| 2074 | * ll_rd_*()-style functions. |
| 2075 | */ |
Peng Tao | 73bb1da | 2013-05-29 21:40:55 +0800 | [diff] [blame] | 2076 | int cl_site_stats_print(const struct cl_site *site, struct seq_file *m); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2077 | |
| 2078 | /** |
| 2079 | * \name helpers |
| 2080 | * |
| 2081 | * Type conversion and accessory functions. |
| 2082 | */ |
| 2083 | /** @{ */ |
| 2084 | |
| 2085 | static inline struct cl_site *lu2cl_site(const struct lu_site *site) |
| 2086 | { |
| 2087 | return container_of(site, struct cl_site, cs_lu); |
| 2088 | } |
| 2089 | |
| 2090 | static inline int lu_device_is_cl(const struct lu_device *d) |
| 2091 | { |
| 2092 | return d->ld_type->ldt_tags & LU_DEVICE_CL; |
| 2093 | } |
| 2094 | |
| 2095 | static inline struct cl_device *lu2cl_dev(const struct lu_device *d) |
| 2096 | { |
Oleg Drokin | d2a1398 | 2016-02-16 00:46:52 -0500 | [diff] [blame] | 2097 | LASSERT(!d || IS_ERR(d) || lu_device_is_cl(d)); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2098 | return container_of0(d, struct cl_device, cd_lu_dev); |
| 2099 | } |
| 2100 | |
| 2101 | static inline struct lu_device *cl2lu_dev(struct cl_device *d) |
| 2102 | { |
| 2103 | return &d->cd_lu_dev; |
| 2104 | } |
| 2105 | |
| 2106 | static inline struct cl_object *lu2cl(const struct lu_object *o) |
| 2107 | { |
Oleg Drokin | d2a1398 | 2016-02-16 00:46:52 -0500 | [diff] [blame] | 2108 | LASSERT(!o || IS_ERR(o) || lu_device_is_cl(o->lo_dev)); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2109 | return container_of0(o, struct cl_object, co_lu); |
| 2110 | } |
| 2111 | |
| 2112 | static inline const struct cl_object_conf * |
| 2113 | lu2cl_conf(const struct lu_object_conf *conf) |
| 2114 | { |
| 2115 | return container_of0(conf, struct cl_object_conf, coc_lu); |
| 2116 | } |
| 2117 | |
| 2118 | static inline struct cl_object *cl_object_next(const struct cl_object *obj) |
| 2119 | { |
| 2120 | return obj ? lu2cl(lu_object_next(&obj->co_lu)) : NULL; |
| 2121 | } |
| 2122 | |
| 2123 | static inline struct cl_device *cl_object_device(const struct cl_object *o) |
| 2124 | { |
Oleg Drokin | d2a1398 | 2016-02-16 00:46:52 -0500 | [diff] [blame] | 2125 | LASSERT(!o || IS_ERR(o) || lu_device_is_cl(o->co_lu.lo_dev)); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2126 | return container_of0(o->co_lu.lo_dev, struct cl_device, cd_lu_dev); |
| 2127 | } |
| 2128 | |
| 2129 | static inline struct cl_object_header *luh2coh(const struct lu_object_header *h) |
| 2130 | { |
| 2131 | return container_of0(h, struct cl_object_header, coh_lu); |
| 2132 | } |
| 2133 | |
| 2134 | static inline struct cl_site *cl_object_site(const struct cl_object *obj) |
| 2135 | { |
| 2136 | return lu2cl_site(obj->co_lu.lo_dev->ld_site); |
| 2137 | } |
| 2138 | |
| 2139 | static inline |
| 2140 | struct cl_object_header *cl_object_header(const struct cl_object *obj) |
| 2141 | { |
| 2142 | return luh2coh(obj->co_lu.lo_header); |
| 2143 | } |
| 2144 | |
| 2145 | static inline int cl_device_init(struct cl_device *d, struct lu_device_type *t) |
| 2146 | { |
| 2147 | return lu_device_init(&d->cd_lu_dev, t); |
| 2148 | } |
| 2149 | |
| 2150 | static inline void cl_device_fini(struct cl_device *d) |
| 2151 | { |
| 2152 | lu_device_fini(&d->cd_lu_dev); |
| 2153 | } |
| 2154 | |
| 2155 | void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice, |
Jinshan Xiong | fd7444f | 2016-03-30 19:48:33 -0400 | [diff] [blame] | 2156 | struct cl_object *obj, pgoff_t index, |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2157 | const struct cl_page_operations *ops); |
| 2158 | void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice, |
| 2159 | struct cl_object *obj, |
| 2160 | const struct cl_lock_operations *ops); |
| 2161 | void cl_io_slice_add(struct cl_io *io, struct cl_io_slice *slice, |
| 2162 | struct cl_object *obj, const struct cl_io_operations *ops); |
| 2163 | void cl_req_slice_add(struct cl_req *req, struct cl_req_slice *slice, |
| 2164 | struct cl_device *dev, |
| 2165 | const struct cl_req_operations *ops); |
| 2166 | /** @} helpers */ |
| 2167 | |
| 2168 | /** \defgroup cl_object cl_object |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2169 | * @{ |
| 2170 | */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2171 | struct cl_object *cl_object_top(struct cl_object *o); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2172 | struct cl_object *cl_object_find(const struct lu_env *env, struct cl_device *cd, |
| 2173 | const struct lu_fid *fid, |
| 2174 | const struct cl_object_conf *c); |
| 2175 | |
| 2176 | int cl_object_header_init(struct cl_object_header *h); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2177 | void cl_object_put(const struct lu_env *env, struct cl_object *o); |
| 2178 | void cl_object_get(struct cl_object *o); |
| 2179 | void cl_object_attr_lock(struct cl_object *o); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2180 | void cl_object_attr_unlock(struct cl_object *o); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2181 | int cl_object_attr_get(const struct lu_env *env, struct cl_object *obj, |
| 2182 | struct cl_attr *attr); |
| 2183 | int cl_object_attr_set(const struct lu_env *env, struct cl_object *obj, |
| 2184 | const struct cl_attr *attr, unsigned valid); |
| 2185 | int cl_object_glimpse(const struct lu_env *env, struct cl_object *obj, |
| 2186 | struct ost_lvb *lvb); |
| 2187 | int cl_conf_set(const struct lu_env *env, struct cl_object *obj, |
| 2188 | const struct cl_object_conf *conf); |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 2189 | int cl_object_prune(const struct lu_env *env, struct cl_object *obj); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2190 | void cl_object_kill(const struct lu_env *env, struct cl_object *obj); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2191 | |
| 2192 | /** |
| 2193 | * Returns true, iff \a o0 and \a o1 are slices of the same object. |
| 2194 | */ |
| 2195 | static inline int cl_object_same(struct cl_object *o0, struct cl_object *o1) |
| 2196 | { |
| 2197 | return cl_object_header(o0) == cl_object_header(o1); |
| 2198 | } |
| 2199 | |
| 2200 | static inline void cl_object_page_init(struct cl_object *clob, int size) |
| 2201 | { |
| 2202 | clob->co_slice_off = cl_object_header(clob)->coh_page_bufsize; |
Jinshan Xiong | 7addf40 | 2016-03-30 19:48:32 -0400 | [diff] [blame] | 2203 | cl_object_header(clob)->coh_page_bufsize += cfs_size_round(size); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2204 | } |
| 2205 | |
| 2206 | static inline void *cl_object_page_slice(struct cl_object *clob, |
| 2207 | struct cl_page *page) |
| 2208 | { |
| 2209 | return (void *)((char *)page + clob->co_slice_off); |
| 2210 | } |
| 2211 | |
Jinshan Xiong | 3c361c1 | 2016-03-30 19:48:29 -0400 | [diff] [blame] | 2212 | /** |
| 2213 | * Return refcount of cl_object. |
| 2214 | */ |
| 2215 | static inline int cl_object_refc(struct cl_object *clob) |
| 2216 | { |
| 2217 | struct lu_object_header *header = clob->co_lu.lo_header; |
| 2218 | |
| 2219 | return atomic_read(&header->loh_ref); |
| 2220 | } |
| 2221 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2222 | /** @} cl_object */ |
| 2223 | |
| 2224 | /** \defgroup cl_page cl_page |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2225 | * @{ |
| 2226 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2227 | enum { |
| 2228 | CLP_GANG_OKAY = 0, |
| 2229 | CLP_GANG_RESCHED, |
| 2230 | CLP_GANG_AGAIN, |
| 2231 | CLP_GANG_ABORT |
| 2232 | }; |
| 2233 | |
| 2234 | /* callback of cl_page_gang_lookup() */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2235 | struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *obj, |
| 2236 | pgoff_t idx, struct page *vmpage, |
| 2237 | enum cl_page_type type); |
Jinshan Xiong | d9d4790 | 2016-03-30 19:48:28 -0400 | [diff] [blame] | 2238 | struct cl_page *cl_page_alloc(const struct lu_env *env, |
| 2239 | struct cl_object *o, pgoff_t ind, |
| 2240 | struct page *vmpage, |
| 2241 | enum cl_page_type type); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2242 | void cl_page_get(struct cl_page *page); |
| 2243 | void cl_page_put(const struct lu_env *env, struct cl_page *page); |
| 2244 | void cl_page_print(const struct lu_env *env, void *cookie, lu_printer_t printer, |
| 2245 | const struct cl_page *pg); |
| 2246 | void cl_page_header_print(const struct lu_env *env, void *cookie, |
| 2247 | lu_printer_t printer, const struct cl_page *pg); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2248 | struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2249 | |
| 2250 | const struct cl_page_slice *cl_page_at(const struct cl_page *page, |
| 2251 | const struct lu_device_type *dtype); |
| 2252 | |
| 2253 | /** |
| 2254 | * \name ownership |
| 2255 | * |
| 2256 | * Functions dealing with the ownership of page by io. |
| 2257 | */ |
| 2258 | /** @{ */ |
| 2259 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2260 | int cl_page_own(const struct lu_env *env, |
| 2261 | struct cl_io *io, struct cl_page *page); |
| 2262 | int cl_page_own_try(const struct lu_env *env, |
| 2263 | struct cl_io *io, struct cl_page *page); |
| 2264 | void cl_page_assume(const struct lu_env *env, |
| 2265 | struct cl_io *io, struct cl_page *page); |
| 2266 | void cl_page_unassume(const struct lu_env *env, |
| 2267 | struct cl_io *io, struct cl_page *pg); |
| 2268 | void cl_page_disown(const struct lu_env *env, |
| 2269 | struct cl_io *io, struct cl_page *page); |
| 2270 | int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2271 | |
| 2272 | /** @} ownership */ |
| 2273 | |
| 2274 | /** |
| 2275 | * \name transfer |
| 2276 | * |
| 2277 | * Functions dealing with the preparation of a page for a transfer, and |
| 2278 | * tracking transfer state. |
| 2279 | */ |
| 2280 | /** @{ */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2281 | int cl_page_prep(const struct lu_env *env, struct cl_io *io, |
| 2282 | struct cl_page *pg, enum cl_req_type crt); |
| 2283 | void cl_page_completion(const struct lu_env *env, |
| 2284 | struct cl_page *pg, enum cl_req_type crt, int ioret); |
| 2285 | int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg, |
| 2286 | enum cl_req_type crt); |
| 2287 | int cl_page_cache_add(const struct lu_env *env, struct cl_io *io, |
| 2288 | struct cl_page *pg, enum cl_req_type crt); |
| 2289 | void cl_page_clip(const struct lu_env *env, struct cl_page *pg, |
| 2290 | int from, int to); |
| 2291 | int cl_page_cancel(const struct lu_env *env, struct cl_page *page); |
| 2292 | int cl_page_flush(const struct lu_env *env, struct cl_io *io, |
| 2293 | struct cl_page *pg); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2294 | |
| 2295 | /** @} transfer */ |
| 2296 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2297 | /** |
| 2298 | * \name helper routines |
| 2299 | * Functions to discard, delete and export a cl_page. |
| 2300 | */ |
| 2301 | /** @{ */ |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2302 | void cl_page_discard(const struct lu_env *env, struct cl_io *io, |
| 2303 | struct cl_page *pg); |
| 2304 | void cl_page_delete(const struct lu_env *env, struct cl_page *pg); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2305 | int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg); |
| 2306 | void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate); |
| 2307 | int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io, |
Jinshan Xiong | fd7444f | 2016-03-30 19:48:33 -0400 | [diff] [blame] | 2308 | struct cl_page *page, pgoff_t *max_index); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2309 | loff_t cl_offset(const struct cl_object *obj, pgoff_t idx); |
| 2310 | pgoff_t cl_index(const struct cl_object *obj, loff_t offset); |
| 2311 | int cl_page_size(const struct cl_object *obj); |
| 2312 | int cl_pages_prune(const struct lu_env *env, struct cl_object *obj); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2313 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2314 | void cl_lock_print(const struct lu_env *env, void *cookie, |
| 2315 | lu_printer_t printer, const struct cl_lock *lock); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2316 | void cl_lock_descr_print(const struct lu_env *env, void *cookie, |
| 2317 | lu_printer_t printer, |
| 2318 | const struct cl_lock_descr *descr); |
| 2319 | /* @} helper */ |
| 2320 | |
John L. Hammond | 0d34565 | 2016-03-30 19:48:45 -0400 | [diff] [blame] | 2321 | /** |
| 2322 | * Data structure managing a client's cached pages. A count of |
| 2323 | * "unstable" pages is maintained, and an LRU of clean pages is |
| 2324 | * maintained. "unstable" pages are pages pinned by the ptlrpc |
| 2325 | * layer for recovery purposes. |
| 2326 | */ |
| 2327 | struct cl_client_cache { |
| 2328 | /** |
| 2329 | * # of users (OSCs) |
| 2330 | */ |
| 2331 | atomic_t ccc_users; |
| 2332 | /** |
| 2333 | * # of threads are doing shrinking |
| 2334 | */ |
| 2335 | unsigned int ccc_lru_shrinkers; |
| 2336 | /** |
| 2337 | * # of LRU entries available |
| 2338 | */ |
| 2339 | atomic_t ccc_lru_left; |
| 2340 | /** |
| 2341 | * List of entities(OSCs) for this LRU cache |
| 2342 | */ |
| 2343 | struct list_head ccc_lru; |
| 2344 | /** |
| 2345 | * Max # of LRU entries |
| 2346 | */ |
| 2347 | unsigned long ccc_lru_max; |
| 2348 | /** |
| 2349 | * Lock to protect ccc_lru list |
| 2350 | */ |
| 2351 | spinlock_t ccc_lru_lock; |
Prakash Surya | ac5b148 | 2016-04-27 18:21:04 -0400 | [diff] [blame] | 2352 | /** |
| 2353 | * # of unstable pages for this mount point |
| 2354 | */ |
| 2355 | atomic_t ccc_unstable_nr; |
| 2356 | /** |
| 2357 | * Waitq for awaiting unstable pages to reach zero. |
| 2358 | * Used at umounting time and signaled on BRW commit |
| 2359 | */ |
| 2360 | wait_queue_head_t ccc_unstable_waitq; |
| 2361 | |
John L. Hammond | 0d34565 | 2016-03-30 19:48:45 -0400 | [diff] [blame] | 2362 | }; |
| 2363 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2364 | /** @} cl_page */ |
| 2365 | |
| 2366 | /** \defgroup cl_lock cl_lock |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2367 | * @{ |
| 2368 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2369 | |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 2370 | int cl_lock_request(const struct lu_env *env, struct cl_io *io, |
| 2371 | struct cl_lock *lock); |
| 2372 | int cl_lock_init(const struct lu_env *env, struct cl_lock *lock, |
| 2373 | const struct cl_io *io); |
| 2374 | void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2375 | const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock, |
| 2376 | const struct lu_device_type *dtype); |
Jinshan Xiong | 06563b5 | 2016-03-30 19:48:40 -0400 | [diff] [blame] | 2377 | void cl_lock_release(const struct lu_env *env, struct cl_lock *lock); |
| 2378 | int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io, |
| 2379 | struct cl_lock *lock, struct cl_sync_io *anchor); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2380 | void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2381 | |
| 2382 | /** @} cl_lock */ |
| 2383 | |
| 2384 | /** \defgroup cl_io cl_io |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2385 | * @{ |
| 2386 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2387 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2388 | int cl_io_init(const struct lu_env *env, struct cl_io *io, |
| 2389 | enum cl_io_type iot, struct cl_object *obj); |
| 2390 | int cl_io_sub_init(const struct lu_env *env, struct cl_io *io, |
| 2391 | enum cl_io_type iot, struct cl_object *obj); |
| 2392 | int cl_io_rw_init(const struct lu_env *env, struct cl_io *io, |
| 2393 | enum cl_io_type iot, loff_t pos, size_t count); |
| 2394 | int cl_io_loop(const struct lu_env *env, struct cl_io *io); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2395 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2396 | void cl_io_fini(const struct lu_env *env, struct cl_io *io); |
| 2397 | int cl_io_iter_init(const struct lu_env *env, struct cl_io *io); |
| 2398 | void cl_io_iter_fini(const struct lu_env *env, struct cl_io *io); |
| 2399 | int cl_io_lock(const struct lu_env *env, struct cl_io *io); |
| 2400 | void cl_io_unlock(const struct lu_env *env, struct cl_io *io); |
| 2401 | int cl_io_start(const struct lu_env *env, struct cl_io *io); |
| 2402 | void cl_io_end(const struct lu_env *env, struct cl_io *io); |
| 2403 | int cl_io_lock_add(const struct lu_env *env, struct cl_io *io, |
| 2404 | struct cl_io_lock_link *link); |
| 2405 | int cl_io_lock_alloc_add(const struct lu_env *env, struct cl_io *io, |
| 2406 | struct cl_lock_descr *descr); |
| 2407 | int cl_io_read_page(const struct lu_env *env, struct cl_io *io, |
| 2408 | struct cl_page *page); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2409 | int cl_io_submit_rw(const struct lu_env *env, struct cl_io *io, |
| 2410 | enum cl_req_type iot, struct cl_2queue *queue); |
| 2411 | int cl_io_submit_sync(const struct lu_env *env, struct cl_io *io, |
| 2412 | enum cl_req_type iot, struct cl_2queue *queue, |
| 2413 | long timeout); |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 2414 | int cl_io_commit_async(const struct lu_env *env, struct cl_io *io, |
| 2415 | struct cl_page_list *queue, int from, int to, |
| 2416 | cl_commit_cbt cb); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2417 | int cl_io_is_going(const struct lu_env *env); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2418 | |
| 2419 | /** |
| 2420 | * True, iff \a io is an O_APPEND write(2). |
| 2421 | */ |
| 2422 | static inline int cl_io_is_append(const struct cl_io *io) |
| 2423 | { |
| 2424 | return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_append; |
| 2425 | } |
| 2426 | |
| 2427 | static inline int cl_io_is_sync_write(const struct cl_io *io) |
| 2428 | { |
| 2429 | return io->ci_type == CIT_WRITE && io->u.ci_wr.wr_sync; |
| 2430 | } |
| 2431 | |
| 2432 | static inline int cl_io_is_mkwrite(const struct cl_io *io) |
| 2433 | { |
| 2434 | return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite; |
| 2435 | } |
| 2436 | |
| 2437 | /** |
| 2438 | * True, iff \a io is a truncate(2). |
| 2439 | */ |
| 2440 | static inline int cl_io_is_trunc(const struct cl_io *io) |
| 2441 | { |
| 2442 | return io->ci_type == CIT_SETATTR && |
| 2443 | (io->u.ci_setattr.sa_valid & ATTR_SIZE); |
| 2444 | } |
| 2445 | |
| 2446 | struct cl_io *cl_io_top(struct cl_io *io); |
| 2447 | |
Joe Perches | ec83e61 | 2013-10-13 20:22:03 -0700 | [diff] [blame] | 2448 | #define CL_IO_SLICE_CLEAN(foo_io, base) \ |
| 2449 | do { \ |
| 2450 | typeof(foo_io) __foo_io = (foo_io); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2451 | \ |
Joe Perches | ec83e61 | 2013-10-13 20:22:03 -0700 | [diff] [blame] | 2452 | CLASSERT(offsetof(typeof(*__foo_io), base) == 0); \ |
| 2453 | memset(&__foo_io->base + 1, 0, \ |
| 2454 | sizeof(*__foo_io) - sizeof(__foo_io->base)); \ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2455 | } while (0) |
| 2456 | |
| 2457 | /** @} cl_io */ |
| 2458 | |
| 2459 | /** \defgroup cl_page_list cl_page_list |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2460 | * @{ |
| 2461 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2462 | |
| 2463 | /** |
| 2464 | * Last page in the page list. |
| 2465 | */ |
| 2466 | static inline struct cl_page *cl_page_list_last(struct cl_page_list *plist) |
| 2467 | { |
| 2468 | LASSERT(plist->pl_nr > 0); |
| 2469 | return list_entry(plist->pl_pages.prev, struct cl_page, cp_batch); |
| 2470 | } |
| 2471 | |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 2472 | static inline struct cl_page *cl_page_list_first(struct cl_page_list *plist) |
| 2473 | { |
| 2474 | LASSERT(plist->pl_nr > 0); |
| 2475 | return list_entry(plist->pl_pages.next, struct cl_page, cp_batch); |
| 2476 | } |
| 2477 | |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2478 | /** |
| 2479 | * Iterate over pages in a page list. |
| 2480 | */ |
| 2481 | #define cl_page_list_for_each(page, list) \ |
| 2482 | list_for_each_entry((page), &(list)->pl_pages, cp_batch) |
| 2483 | |
| 2484 | /** |
| 2485 | * Iterate over pages in a page list, taking possible removals into account. |
| 2486 | */ |
| 2487 | #define cl_page_list_for_each_safe(page, temp, list) \ |
| 2488 | list_for_each_entry_safe((page), (temp), &(list)->pl_pages, cp_batch) |
| 2489 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2490 | void cl_page_list_init(struct cl_page_list *plist); |
| 2491 | void cl_page_list_add(struct cl_page_list *plist, struct cl_page *page); |
| 2492 | void cl_page_list_move(struct cl_page_list *dst, struct cl_page_list *src, |
| 2493 | struct cl_page *page); |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 2494 | void cl_page_list_move_head(struct cl_page_list *dst, struct cl_page_list *src, |
| 2495 | struct cl_page *page); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2496 | void cl_page_list_splice(struct cl_page_list *list, struct cl_page_list *head); |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 2497 | void cl_page_list_del(const struct lu_env *env, struct cl_page_list *plist, |
| 2498 | struct cl_page *page); |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2499 | void cl_page_list_disown(const struct lu_env *env, |
| 2500 | struct cl_io *io, struct cl_page_list *plist); |
Jinshan Xiong | 77605e4 | 2016-03-30 19:48:30 -0400 | [diff] [blame] | 2501 | void cl_page_list_fini(const struct lu_env *env, struct cl_page_list *plist); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2502 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2503 | void cl_2queue_init(struct cl_2queue *queue); |
| 2504 | void cl_2queue_disown(const struct lu_env *env, |
| 2505 | struct cl_io *io, struct cl_2queue *queue); |
| 2506 | void cl_2queue_discard(const struct lu_env *env, |
| 2507 | struct cl_io *io, struct cl_2queue *queue); |
| 2508 | void cl_2queue_fini(const struct lu_env *env, struct cl_2queue *queue); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2509 | void cl_2queue_init_page(struct cl_2queue *queue, struct cl_page *page); |
| 2510 | |
| 2511 | /** @} cl_page_list */ |
| 2512 | |
| 2513 | /** \defgroup cl_req cl_req |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2514 | * @{ |
| 2515 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2516 | struct cl_req *cl_req_alloc(const struct lu_env *env, struct cl_page *page, |
| 2517 | enum cl_req_type crt, int nr_objects); |
| 2518 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2519 | void cl_req_page_add(const struct lu_env *env, struct cl_req *req, |
| 2520 | struct cl_page *page); |
| 2521 | void cl_req_page_done(const struct lu_env *env, struct cl_page *page); |
| 2522 | int cl_req_prep(const struct lu_env *env, struct cl_req *req); |
| 2523 | void cl_req_attr_set(const struct lu_env *env, struct cl_req *req, |
| 2524 | struct cl_req_attr *attr, u64 flags); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2525 | void cl_req_completion(const struct lu_env *env, struct cl_req *req, int ioret); |
| 2526 | |
| 2527 | /** \defgroup cl_sync_io cl_sync_io |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2528 | * @{ |
| 2529 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2530 | |
| 2531 | /** |
| 2532 | * Anchor for synchronous transfer. This is allocated on a stack by thread |
| 2533 | * doing synchronous transfer, and a pointer to this structure is set up in |
| 2534 | * every page submitted for transfer. Transfer completion routine updates |
| 2535 | * anchor and wakes up waiting thread when transfer is complete. |
| 2536 | */ |
| 2537 | struct cl_sync_io { |
| 2538 | /** number of pages yet to be transferred. */ |
| 2539 | atomic_t csi_sync_nr; |
| 2540 | /** error code. */ |
| 2541 | int csi_sync_rc; |
| 2542 | /** barrier of destroy this structure */ |
| 2543 | atomic_t csi_barrier; |
| 2544 | /** completion to be signaled when transfer is complete. */ |
| 2545 | wait_queue_head_t csi_waitq; |
Jinshan Xiong | e5c4e63 | 2016-03-30 19:48:39 -0400 | [diff] [blame] | 2546 | /** callback to invoke when this IO is finished */ |
| 2547 | void (*csi_end_io)(const struct lu_env *, |
| 2548 | struct cl_sync_io *); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2549 | }; |
| 2550 | |
Jinshan Xiong | e5c4e63 | 2016-03-30 19:48:39 -0400 | [diff] [blame] | 2551 | void cl_sync_io_init(struct cl_sync_io *anchor, int nr, |
| 2552 | void (*end)(const struct lu_env *, struct cl_sync_io *)); |
| 2553 | int cl_sync_io_wait(const struct lu_env *env, struct cl_sync_io *anchor, |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2554 | long timeout); |
Jinshan Xiong | e5c4e63 | 2016-03-30 19:48:39 -0400 | [diff] [blame] | 2555 | void cl_sync_io_note(const struct lu_env *env, struct cl_sync_io *anchor, |
| 2556 | int ioret); |
| 2557 | void cl_sync_io_end(const struct lu_env *env, struct cl_sync_io *anchor); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2558 | |
| 2559 | /** @} cl_sync_io */ |
| 2560 | |
| 2561 | /** @} cl_req */ |
| 2562 | |
| 2563 | /** \defgroup cl_env cl_env |
| 2564 | * |
| 2565 | * lu_env handling for a client. |
| 2566 | * |
| 2567 | * lu_env is an environment within which lustre code executes. Its major part |
| 2568 | * is lu_context---a fast memory allocation mechanism that is used to conserve |
| 2569 | * precious kernel stack space. Originally lu_env was designed for a server, |
| 2570 | * where |
| 2571 | * |
| 2572 | * - there is a (mostly) fixed number of threads, and |
| 2573 | * |
| 2574 | * - call chains have no non-lustre portions inserted between lustre code. |
| 2575 | * |
Masanari Iida | bd9070c | 2014-03-08 22:58:34 +0900 | [diff] [blame] | 2576 | * On a client both these assumption fails, because every user thread can |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2577 | * potentially execute lustre code as part of a system call, and lustre calls |
| 2578 | * into VFS or MM that call back into lustre. |
| 2579 | * |
| 2580 | * To deal with that, cl_env wrapper functions implement the following |
| 2581 | * optimizations: |
| 2582 | * |
| 2583 | * - allocation and destruction of environment is amortized by caching no |
| 2584 | * longer used environments instead of destroying them; |
| 2585 | * |
| 2586 | * - there is a notion of "current" environment, attached to the kernel |
| 2587 | * data structure representing current thread Top-level lustre code |
| 2588 | * allocates an environment and makes it current, then calls into |
| 2589 | * non-lustre code, that in turn calls lustre back. Low-level lustre |
| 2590 | * code thus called can fetch environment created by the top-level code |
| 2591 | * and reuse it, avoiding additional environment allocation. |
| 2592 | * Right now, three interfaces can attach the cl_env to running thread: |
| 2593 | * - cl_env_get |
| 2594 | * - cl_env_implant |
| 2595 | * - cl_env_reexit(cl_env_reenter had to be called priorly) |
| 2596 | * |
| 2597 | * \see lu_env, lu_context, lu_context_key |
Oleg Drokin | c56e256 | 2016-02-24 22:00:25 -0500 | [diff] [blame] | 2598 | * @{ |
| 2599 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2600 | |
| 2601 | struct cl_env_nest { |
| 2602 | int cen_refcheck; |
| 2603 | void *cen_cookie; |
| 2604 | }; |
| 2605 | |
Oleg Drokin | 10457d4 | 2016-02-26 01:49:50 -0500 | [diff] [blame] | 2606 | struct lu_env *cl_env_get(int *refcheck); |
| 2607 | struct lu_env *cl_env_alloc(int *refcheck, __u32 tags); |
| 2608 | struct lu_env *cl_env_nested_get(struct cl_env_nest *nest); |
| 2609 | void cl_env_put(struct lu_env *env, int *refcheck); |
| 2610 | void cl_env_nested_put(struct cl_env_nest *nest, struct lu_env *env); |
| 2611 | void *cl_env_reenter(void); |
| 2612 | void cl_env_reexit(void *cookie); |
| 2613 | void cl_env_implant(struct lu_env *env, int *refcheck); |
| 2614 | void cl_env_unplant(struct lu_env *env, int *refcheck); |
Jinshan Xiong | 26f98e8 | 2016-03-30 19:48:25 -0400 | [diff] [blame] | 2615 | unsigned int cl_env_cache_purge(unsigned int nr); |
Jinshan Xiong | 3c361c1 | 2016-03-30 19:48:29 -0400 | [diff] [blame] | 2616 | struct lu_env *cl_env_percpu_get(void); |
| 2617 | void cl_env_percpu_put(struct lu_env *env); |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2618 | |
| 2619 | /** @} cl_env */ |
| 2620 | |
| 2621 | /* |
| 2622 | * Misc |
| 2623 | */ |
Peng Tao | d7e09d0 | 2013-05-02 16:46:55 +0800 | [diff] [blame] | 2624 | void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb); |
| 2625 | |
| 2626 | struct cl_device *cl_type_setup(const struct lu_env *env, struct lu_site *site, |
| 2627 | struct lu_device_type *ldt, |
| 2628 | struct lu_device *next); |
| 2629 | /** @} clio */ |
| 2630 | |
| 2631 | int cl_global_init(void); |
| 2632 | void cl_global_fini(void); |
| 2633 | |
| 2634 | #endif /* _LINUX_CL_OBJECT_H */ |