1/*- 2 * Copyright 1998, 2000 Marshall Kirk McKusick. All Rights Reserved. 3 * 4 * The soft updates code is derived from the appendix of a University 5 * of Michigan technical report (Gregory R. Ganger and Yale N. Patt, 6 * "Soft Updates: A Solution to the Metadata Update Problem in File 7 * Systems", CSE-TR-254-95, August 1995). 8 * 9 * Further information about soft updates can be obtained from: 10 * 11 * Marshall Kirk McKusick http://www.mckusick.com/softdep/ 12 * 1614 Oxford Street mckusick@mckusick.com 13 * Berkeley, CA 94709-1608 +1-510-843-9542 14 * USA 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND ANY 27 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 28 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 29 * DISCLAIMED. IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE FOR 30 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)softdep.h 9.7 (McKusick) 6/21/00 39 * $FreeBSD$ 40 */ 41 42#include <sys/queue.h> 43 44/* 45 * Allocation dependencies are handled with undo/redo on the in-memory 46 * copy of the data. A particular data dependency is eliminated when 47 * it is ALLCOMPLETE: that is ATTACHED, DEPCOMPLETE, and COMPLETE. 48 * 49 * The ATTACHED flag means that the data is not currently being written 50 * to disk. 51 * 52 * The UNDONE flag means that the data has been rolled back to a safe 53 * state for writing to the disk. When the I/O completes, the data is 54 * restored to its current form and the state reverts to ATTACHED. 55 * The data must be locked throughout the rollback, I/O, and roll 56 * forward so that the rolled back information is never visible to 57 * user processes. 58 * 59 * The COMPLETE flag indicates that the item has been written. For example, 60 * a dependency that requires that an inode be written will be marked 61 * COMPLETE after the inode has been written to disk. 62 * 63 * The DEPCOMPLETE flag indicates the completion of any other 64 * dependencies such as the writing of a cylinder group map has been 65 * completed. A dependency structure may be freed only when both it 66 * and its dependencies have completed and any rollbacks that are in 67 * progress have finished as indicated by the set of ALLCOMPLETE flags 68 * all being set. 69 * 70 * The two MKDIR flags indicate additional dependencies that must be done 71 * when creating a new directory. MKDIR_BODY is cleared when the directory 72 * data block containing the "." and ".." entries has been written. 73 * MKDIR_PARENT is cleared when the parent inode with the increased link 74 * count for ".." has been written. When both MKDIR flags have been 75 * cleared, the DEPCOMPLETE flag is set to indicate that the directory 76 * dependencies have been completed. The writing of the directory inode 77 * itself sets the COMPLETE flag which then allows the directory entry for 78 * the new directory to be written to disk. The RMDIR flag marks a dirrem 79 * structure as representing the removal of a directory rather than a 80 * file. When the removal dependencies are completed, additional work needs 81 * to be done* (an additional decrement of the associated inode, and a 82 * decrement of the parent inode). 83 * 84 * The DIRCHG flag marks a diradd structure as representing the changing 85 * of an existing entry rather than the addition of a new one. When 86 * the update is complete the dirrem associated with the inode for 87 * the old name must be added to the worklist to do the necessary 88 * reference count decrement. 89 * 90 * The GOINGAWAY flag indicates that the data structure is frozen from 91 * further change until its dependencies have been completed and its 92 * resources freed after which it will be discarded. 93 * 94 * The IOSTARTED flag prevents multiple calls to the I/O start routine from 95 * doing multiple rollbacks. 96 * 97 * The NEWBLOCK flag marks pagedep structures that have just been allocated, 98 * so must be claimed by the inode before all dependencies are complete. 99 * 100 * The INPROGRESS flag marks worklist structures that are still on the 101 * worklist, but are being considered for action by some process. 102 * 103 * The UFS1FMT flag indicates that the inode being processed is a ufs1 format. 104 * 105 * The EXTDATA flag indicates that the allocdirect describes an 106 * extended-attributes dependency. 107 * 108 * The ONWORKLIST flag shows whether the structure is currently linked 109 * onto a worklist. 110 * 111 * The UNLINK* flags track the progress of updating the on-disk linked 112 * list of active but unlinked inodes. When an inode is first unlinked 113 * it is marked as UNLINKED. When its on-disk di_freelink has been 114 * written its UNLINKNEXT flags is set. When its predecessor in the 115 * list has its di_freelink pointing at us its UNLINKPREV is set. 116 * When the on-disk list can reach it from the superblock, its 117 * UNLINKONLIST flag is set. Once all of these flags are set, it 118 * is safe to let its last name be removed. 119 */ 120#define ATTACHED 0x000001 121#define UNDONE 0x000002 122#define COMPLETE 0x000004 123#define DEPCOMPLETE 0x000008 124#define MKDIR_PARENT 0x000010 /* diradd, mkdir, jaddref, jsegdep only */ 125#define MKDIR_BODY 0x000020 /* diradd, mkdir, jaddref only */ 126#define RMDIR 0x000040 /* dirrem only */ 127#define DIRCHG 0x000080 /* diradd, dirrem only */ 128#define GOINGAWAY 0x000100 /* indirdep, jremref only */ 129#define IOSTARTED 0x000200 /* inodedep, pagedep, bmsafemap only */ 130#define DELAYEDFREE 0x000400 /* allocindirect free delayed. */ 131#define NEWBLOCK 0x000800 /* pagedep, jaddref only */ 132#define INPROGRESS 0x001000 /* dirrem, freeblks, freefrag, freefile only */ 133#define UFS1FMT 0x002000 /* indirdep only */ 134#define EXTDATA 0x004000 /* allocdirect only */ 135#define ONWORKLIST 0x008000 136#define IOWAITING 0x010000 /* Thread is waiting for IO to complete. */ 137#define ONDEPLIST 0x020000 /* Structure is on a dependency list. */ 138#define UNLINKED 0x040000 /* inodedep has been unlinked. */ 139#define UNLINKNEXT 0x080000 /* inodedep has valid di_freelink */ 140#define UNLINKPREV 0x100000 /* inodedep is pointed at in the unlink list */ 141#define UNLINKONLIST 0x200000 /* inodedep is in the unlinked list on disk */ 142#define UNLINKLINKS (UNLINKNEXT | UNLINKPREV) 143 144#define ALLCOMPLETE (ATTACHED | COMPLETE | DEPCOMPLETE) 145 146/* 147 * The workitem queue. 148 * 149 * It is sometimes useful and/or necessary to clean up certain dependencies 150 * in the background rather than during execution of an application process 151 * or interrupt service routine. To realize this, we append dependency 152 * structures corresponding to such tasks to a "workitem" queue. In a soft 153 * updates implementation, most pending workitems should not wait for more 154 * than a couple of seconds, so the filesystem syncer process awakens once 155 * per second to process the items on the queue. 156 */ 157 158/* LIST_HEAD(workhead, worklist); -- declared in buf.h */ 159 160/* 161 * Each request can be linked onto a work queue through its worklist structure. 162 * To avoid the need for a pointer to the structure itself, this structure 163 * MUST be declared FIRST in each type in which it appears! If more than one 164 * worklist is needed in the structure, then a wk_data field must be added 165 * and the macros below changed to use it. 166 */ 167struct worklist { 168 LIST_ENTRY(worklist) wk_list; /* list of work requests */ 169 struct mount *wk_mp; /* Mount we live in */ 170 unsigned int wk_type:8, /* type of request */ 171 wk_state:24; /* state flags */ 172}; 173#define WK_DATA(wk) ((void *)(wk)) 174#define WK_PAGEDEP(wk) ((struct pagedep *)(wk)) 175#define WK_INODEDEP(wk) ((struct inodedep *)(wk)) 176#define WK_BMSAFEMAP(wk) ((struct bmsafemap *)(wk)) 177#define WK_NEWBLK(wk) ((struct newblk *)(wk)) 178#define WK_ALLOCDIRECT(wk) ((struct allocdirect *)(wk)) 179#define WK_INDIRDEP(wk) ((struct indirdep *)(wk)) 180#define WK_ALLOCINDIR(wk) ((struct allocindir *)(wk)) 181#define WK_FREEFRAG(wk) ((struct freefrag *)(wk)) 182#define WK_FREEBLKS(wk) ((struct freeblks *)(wk)) 183#define WK_FREEWORK(wk) ((struct freework *)(wk)) 184#define WK_FREEFILE(wk) ((struct freefile *)(wk)) 185#define WK_DIRADD(wk) ((struct diradd *)(wk)) 186#define WK_MKDIR(wk) ((struct mkdir *)(wk)) 187#define WK_DIRREM(wk) ((struct dirrem *)(wk)) 188#define WK_NEWDIRBLK(wk) ((struct newdirblk *)(wk)) 189#define WK_JADDREF(wk) ((struct jaddref *)(wk)) 190#define WK_JREMREF(wk) ((struct jremref *)(wk)) 191#define WK_JMVREF(wk) ((struct jmvref *)(wk)) 192#define WK_JSEGDEP(wk) ((struct jsegdep *)(wk)) 193#define WK_JSEG(wk) ((struct jseg *)(wk)) 194#define WK_JNEWBLK(wk) ((struct jnewblk *)(wk)) 195#define WK_JFREEBLK(wk) ((struct jfreeblk *)(wk)) 196#define WK_FREEDEP(wk) ((struct freedep *)(wk)) 197#define WK_JFREEFRAG(wk) ((struct jfreefrag *)(wk)) 198#define WK_SBDEP(wk) ((struct sbdep *)(wk)) 199#define WK_JTRUNC(wk) ((struct jtrunc *)(wk)) 200#define WK_JFSYNC(wk) ((struct jfsync *)(wk)) 201 202/* 203 * Various types of lists 204 */ 205LIST_HEAD(dirremhd, dirrem); 206LIST_HEAD(diraddhd, diradd); 207LIST_HEAD(newblkhd, newblk); 208LIST_HEAD(inodedephd, inodedep); 209LIST_HEAD(allocindirhd, allocindir); 210LIST_HEAD(allocdirecthd, allocdirect); 211TAILQ_HEAD(allocdirectlst, allocdirect); 212LIST_HEAD(indirdephd, indirdep); 213LIST_HEAD(jaddrefhd, jaddref); 214LIST_HEAD(jremrefhd, jremref); 215LIST_HEAD(jmvrefhd, jmvref); 216LIST_HEAD(jnewblkhd, jnewblk); 217LIST_HEAD(jblkdephd, jblkdep); 218LIST_HEAD(freeworkhd, freework); 219TAILQ_HEAD(freeworklst, freework); 220TAILQ_HEAD(jseglst, jseg); 221TAILQ_HEAD(inoreflst, inoref); 222TAILQ_HEAD(freeblklst, freeblks); 223 224/* 225 * The "pagedep" structure tracks the various dependencies related to 226 * a particular directory page. If a directory page has any dependencies, 227 * it will have a pagedep linked to its associated buffer. The 228 * pd_dirremhd list holds the list of dirrem requests which decrement 229 * inode reference counts. These requests are processed after the 230 * directory page with the corresponding zero'ed entries has been 231 * written. The pd_diraddhd list maintains the list of diradd requests 232 * which cannot be committed until their corresponding inode has been 233 * written to disk. Because a directory may have many new entries 234 * being created, several lists are maintained hashed on bits of the 235 * offset of the entry into the directory page to keep the lists from 236 * getting too long. Once a new directory entry has been cleared to 237 * be written, it is moved to the pd_pendinghd list. After the new 238 * entry has been written to disk it is removed from the pd_pendinghd 239 * list, any removed operations are done, and the dependency structure 240 * is freed. 241 */ 242#define DAHASHSZ 5 243#define DIRADDHASH(offset) (((offset) >> 2) % DAHASHSZ) 244struct pagedep { 245 struct worklist pd_list; /* page buffer */ 246# define pd_state pd_list.wk_state /* check for multiple I/O starts */ 247 LIST_ENTRY(pagedep) pd_hash; /* hashed lookup */ 248 ino_t pd_ino; /* associated file */ 249 ufs_lbn_t pd_lbn; /* block within file */ 250 struct newdirblk *pd_newdirblk; /* associated newdirblk if NEWBLOCK */ 251 struct dirremhd pd_dirremhd; /* dirrem's waiting for page */ 252 struct diraddhd pd_diraddhd[DAHASHSZ]; /* diradd dir entry updates */ 253 struct diraddhd pd_pendinghd; /* directory entries awaiting write */ 254 struct jmvrefhd pd_jmvrefhd; /* Dependent journal writes. */ 255}; 256 257/* 258 * The "inodedep" structure tracks the set of dependencies associated 259 * with an inode. One task that it must manage is delayed operations 260 * (i.e., work requests that must be held until the inodedep's associated 261 * inode has been written to disk). Getting an inode from its incore 262 * state to the disk requires two steps to be taken by the filesystem 263 * in this order: first the inode must be copied to its disk buffer by 264 * the VOP_UPDATE operation; second the inode's buffer must be written 265 * to disk. To ensure that both operations have happened in the required 266 * order, the inodedep maintains two lists. Delayed operations are 267 * placed on the id_inowait list. When the VOP_UPDATE is done, all 268 * operations on the id_inowait list are moved to the id_bufwait list. 269 * When the buffer is written, the items on the id_bufwait list can be 270 * safely moved to the work queue to be processed. A second task of the 271 * inodedep structure is to track the status of block allocation within 272 * the inode. Each block that is allocated is represented by an 273 * "allocdirect" structure (see below). It is linked onto the id_newinoupdt 274 * list until both its contents and its allocation in the cylinder 275 * group map have been written to disk. Once these dependencies have been 276 * satisfied, it is removed from the id_newinoupdt list and any followup 277 * actions such as releasing the previous block or fragment are placed 278 * on the id_inowait list. When an inode is updated (a VOP_UPDATE is 279 * done), the "inodedep" structure is linked onto the buffer through 280 * its worklist. Thus, it will be notified when the buffer is about 281 * to be written and when it is done. At the update time, all the 282 * elements on the id_newinoupdt list are moved to the id_inoupdt list 283 * since those changes are now relevant to the copy of the inode in the 284 * buffer. Also at update time, the tasks on the id_inowait list are 285 * moved to the id_bufwait list so that they will be executed when 286 * the updated inode has been written to disk. When the buffer containing 287 * the inode is written to disk, any updates listed on the id_inoupdt 288 * list are rolled back as they are not yet safe. Following the write, 289 * the changes are once again rolled forward and any actions on the 290 * id_bufwait list are processed (since those actions are now safe). 291 * The entries on the id_inoupdt and id_newinoupdt lists must be kept 292 * sorted by logical block number to speed the calculation of the size 293 * of the rolled back inode (see explanation in initiate_write_inodeblock). 294 * When a directory entry is created, it is represented by a diradd. 295 * The diradd is added to the id_inowait list as it cannot be safely 296 * written to disk until the inode that it represents is on disk. After 297 * the inode is written, the id_bufwait list is processed and the diradd 298 * entries are moved to the id_pendinghd list where they remain until 299 * the directory block containing the name has been written to disk. 300 * The purpose of keeping the entries on the id_pendinghd list is so that 301 * the softdep_fsync function can find and push the inode's directory 302 * name(s) as part of the fsync operation for that file. 303 */ 304struct inodedep { 305 struct worklist id_list; /* buffer holding inode block */ 306# define id_state id_list.wk_state /* inode dependency state */ 307 LIST_ENTRY(inodedep) id_hash; /* hashed lookup */ 308 TAILQ_ENTRY(inodedep) id_unlinked; /* Unlinked but ref'd inodes */ 309 struct fs *id_fs; /* associated filesystem */ 310 ino_t id_ino; /* dependent inode */ 311 nlink_t id_nlinkdelta; /* saved effective link count */ 312 nlink_t id_savednlink; /* Link saved during rollback */ 313 LIST_ENTRY(inodedep) id_deps; /* bmsafemap's list of inodedep's */ 314 struct bmsafemap *id_bmsafemap; /* related bmsafemap (if pending) */ 315 struct diradd *id_mkdiradd; /* diradd for a mkdir. */ 316 struct inoreflst id_inoreflst; /* Inode reference adjustments. */ 317 long id_savedextsize; /* ext size saved during rollback */ 318 off_t id_savedsize; /* file size saved during rollback */ 319 struct dirremhd id_dirremhd; /* Removals pending. */ 320 struct workhead id_pendinghd; /* entries awaiting directory write */ 321 struct workhead id_bufwait; /* operations after inode written */ 322 struct workhead id_inowait; /* operations waiting inode update */ 323 struct allocdirectlst id_inoupdt; /* updates before inode written */ 324 struct allocdirectlst id_newinoupdt; /* updates when inode written */ 325 struct allocdirectlst id_extupdt; /* extdata updates pre-inode write */ 326 struct allocdirectlst id_newextupdt; /* extdata updates at ino write */ 327 struct freeblklst id_freeblklst; /* List of partial truncates. */ 328 union { 329 struct ufs1_dinode *idu_savedino1; /* saved ufs1_dinode contents */ 330 struct ufs2_dinode *idu_savedino2; /* saved ufs2_dinode contents */ 331 } id_un; 332}; 333#define id_savedino1 id_un.idu_savedino1 334#define id_savedino2 id_un.idu_savedino2 335 336/* 337 * A "bmsafemap" structure maintains a list of dependency structures 338 * that depend on the update of a particular cylinder group map. 339 * It has lists for newblks, allocdirects, allocindirs, and inodedeps. 340 * It is attached to the buffer of a cylinder group block when any of 341 * these things are allocated from the cylinder group. It is freed 342 * after the cylinder group map is written and the state of its 343 * dependencies are updated with DEPCOMPLETE to indicate that it has 344 * been processed. 345 */ 346struct bmsafemap { 347 struct worklist sm_list; /* cylgrp buffer */ 348# define sm_state sm_list.wk_state 349 LIST_ENTRY(bmsafemap) sm_hash; /* Hash links. */ 350 LIST_ENTRY(bmsafemap) sm_next; /* Mount list. */ 351 int sm_cg; 352 struct buf *sm_buf; /* associated buffer */ 353 struct allocdirecthd sm_allocdirecthd; /* allocdirect deps */ 354 struct allocdirecthd sm_allocdirectwr; /* writing allocdirect deps */ 355 struct allocindirhd sm_allocindirhd; /* allocindir deps */ 356 struct allocindirhd sm_allocindirwr; /* writing allocindir deps */ 357 struct inodedephd sm_inodedephd; /* inodedep deps */ 358 struct inodedephd sm_inodedepwr; /* writing inodedep deps */ 359 struct newblkhd sm_newblkhd; /* newblk deps */ 360 struct newblkhd sm_newblkwr; /* writing newblk deps */ 361 struct jaddrefhd sm_jaddrefhd; /* Pending inode allocations. */ 362 struct jnewblkhd sm_jnewblkhd; /* Pending block allocations. */ 363 struct workhead sm_freehd; /* Freedep deps. */ 364 struct workhead sm_freewr; /* Written freedeps. */ 365}; 366 367/* 368 * A "newblk" structure is attached to a bmsafemap structure when a block 369 * or fragment is allocated from a cylinder group. Its state is set to 370 * DEPCOMPLETE when its cylinder group map is written. It is converted to 371 * an allocdirect or allocindir allocation once the allocator calls the 372 * appropriate setup function. It will initially be linked onto a bmsafemap 373 * list. Once converted it can be linked onto the lists described for 374 * allocdirect or allocindir as described below. 375 */ 376struct newblk { 377 struct worklist nb_list; /* See comment above. */ 378# define nb_state nb_list.wk_state 379 LIST_ENTRY(newblk) nb_hash; /* Hashed lookup. */ 380 LIST_ENTRY(newblk) nb_deps; /* Bmsafemap's list of newblks. */ 381 struct jnewblk *nb_jnewblk; /* New block journal entry. */ 382 struct bmsafemap *nb_bmsafemap;/* Cylgrp dep (if pending). */ 383 struct freefrag *nb_freefrag; /* Fragment to be freed (if any). */ 384 struct indirdephd nb_indirdeps; /* Children indirect blocks. */ 385 struct workhead nb_newdirblk; /* Dir block to notify when written. */ 386 struct workhead nb_jwork; /* Journal work pending. */ 387 ufs2_daddr_t nb_newblkno; /* New value of block pointer. */ 388}; 389 390/* 391 * An "allocdirect" structure is attached to an "inodedep" when a new block 392 * or fragment is allocated and pointed to by the inode described by 393 * "inodedep". The worklist is linked to the buffer that holds the block. 394 * When the block is first allocated, it is linked to the bmsafemap 395 * structure associated with the buffer holding the cylinder group map 396 * from which it was allocated. When the cylinder group map is written 397 * to disk, ad_state has the DEPCOMPLETE flag set. When the block itself 398 * is written, the COMPLETE flag is set. Once both the cylinder group map 399 * and the data itself have been written, it is safe to write the inode 400 * that claims the block. If there was a previous fragment that had been 401 * allocated before the file was increased in size, the old fragment may 402 * be freed once the inode claiming the new block is written to disk. 403 * This ad_fragfree request is attached to the id_inowait list of the 404 * associated inodedep (pointed to by ad_inodedep) for processing after 405 * the inode is written. When a block is allocated to a directory, an 406 * fsync of a file whose name is within that block must ensure not only 407 * that the block containing the file name has been written, but also 408 * that the on-disk inode references that block. When a new directory 409 * block is created, we allocate a newdirblk structure which is linked 410 * to the associated allocdirect (on its ad_newdirblk list). When the 411 * allocdirect has been satisfied, the newdirblk structure is moved to 412 * the inodedep id_bufwait list of its directory to await the inode 413 * being written. When the inode is written, the directory entries are 414 * fully committed and can be deleted from their pagedep->id_pendinghd 415 * and inodedep->id_pendinghd lists. 416 */ 417struct allocdirect { 418 struct newblk ad_block; /* Common block logic */ 419# define ad_state ad_block.nb_list.wk_state /* block pointer state */ 420 TAILQ_ENTRY(allocdirect) ad_next; /* inodedep's list of allocdirect's */ 421 struct inodedep *ad_inodedep; /* associated inodedep */ 422 ufs2_daddr_t ad_oldblkno; /* old value of block pointer */ 423 int ad_offset; /* Pointer offset in parent. */ 424 long ad_newsize; /* size of new block */ 425 long ad_oldsize; /* size of old block */ 426}; 427#define ad_newblkno ad_block.nb_newblkno 428#define ad_freefrag ad_block.nb_freefrag 429#define ad_newdirblk ad_block.nb_newdirblk 430 431/* 432 * A single "indirdep" structure manages all allocation dependencies for 433 * pointers in an indirect block. The up-to-date state of the indirect 434 * block is stored in ir_savedata. The set of pointers that may be safely 435 * written to the disk is stored in ir_safecopy. The state field is used 436 * only to track whether the buffer is currently being written (in which 437 * case it is not safe to update ir_safecopy). Ir_deplisthd contains the 438 * list of allocindir structures, one for each block that needs to be 439 * written to disk. Once the block and its bitmap allocation have been 440 * written the safecopy can be updated to reflect the allocation and the 441 * allocindir structure freed. If ir_state indicates that an I/O on the 442 * indirect block is in progress when ir_safecopy is to be updated, the 443 * update is deferred by placing the allocindir on the ir_donehd list. 444 * When the I/O on the indirect block completes, the entries on the 445 * ir_donehd list are processed by updating their corresponding ir_safecopy 446 * pointers and then freeing the allocindir structure. 447 */ 448struct indirdep { 449 struct worklist ir_list; /* buffer holding indirect block */ 450# define ir_state ir_list.wk_state /* indirect block pointer state */ 451 LIST_ENTRY(indirdep) ir_next; /* alloc{direct,indir} list */ 452 TAILQ_HEAD(, freework) ir_trunc; /* List of truncations. */ 453 caddr_t ir_saveddata; /* buffer cache contents */ 454 struct buf *ir_savebp; /* buffer holding safe copy */ 455 struct buf *ir_bp; /* buffer holding live copy */ 456 struct allocindirhd ir_completehd; /* waiting for indirdep complete */ 457 struct allocindirhd ir_writehd; /* Waiting for the pointer write. */ 458 struct allocindirhd ir_donehd; /* done waiting to update safecopy */ 459 struct allocindirhd ir_deplisthd; /* allocindir deps for this block */ 460 struct freeblks *ir_freeblks; /* Freeblks that frees this indir. */ 461}; 462 463/* 464 * An "allocindir" structure is attached to an "indirdep" when a new block 465 * is allocated and pointed to by the indirect block described by the 466 * "indirdep". The worklist is linked to the buffer that holds the new block. 467 * When the block is first allocated, it is linked to the bmsafemap 468 * structure associated with the buffer holding the cylinder group map 469 * from which it was allocated. When the cylinder group map is written 470 * to disk, ai_state has the DEPCOMPLETE flag set. When the block itself 471 * is written, the COMPLETE flag is set. Once both the cylinder group map 472 * and the data itself have been written, it is safe to write the entry in 473 * the indirect block that claims the block; the "allocindir" dependency 474 * can then be freed as it is no longer applicable. 475 */ 476struct allocindir { 477 struct newblk ai_block; /* Common block area */ 478# define ai_state ai_block.nb_list.wk_state /* indirect pointer state */ 479 LIST_ENTRY(allocindir) ai_next; /* indirdep's list of allocindir's */ 480 struct indirdep *ai_indirdep; /* address of associated indirdep */ 481 ufs2_daddr_t ai_oldblkno; /* old value of block pointer */ 482 ufs_lbn_t ai_lbn; /* Logical block number. */ 483 int ai_offset; /* Pointer offset in parent. */ 484}; 485#define ai_newblkno ai_block.nb_newblkno 486#define ai_freefrag ai_block.nb_freefrag 487#define ai_newdirblk ai_block.nb_newdirblk 488 489/* 490 * The allblk union is used to size the newblk structure on allocation so 491 * that it may be any one of three types. 492 */ 493union allblk { 494 struct allocindir ab_allocindir; 495 struct allocdirect ab_allocdirect; 496 struct newblk ab_newblk; 497}; 498 499/* 500 * A "freefrag" structure is attached to an "inodedep" when a previously 501 * allocated fragment is replaced with a larger fragment, rather than extended. 502 * The "freefrag" structure is constructed and attached when the replacement 503 * block is first allocated. It is processed after the inode claiming the 504 * bigger block that replaces it has been written to disk. 505 */ 506struct freefrag { 507 struct worklist ff_list; /* id_inowait or delayed worklist */ 508# define ff_state ff_list.wk_state 509 struct worklist *ff_jdep; /* Associated journal entry. */ 510 struct workhead ff_jwork; /* Journal work pending. */ 511 ufs2_daddr_t ff_blkno; /* fragment physical block number */ 512 long ff_fragsize; /* size of fragment being deleted */ 513 ino_t ff_inum; /* owning inode number */ 514 enum vtype ff_vtype; /* owning inode's file type */ 515}; 516 517/* 518 * A "freeblks" structure is attached to an "inodedep" when the 519 * corresponding file's length is reduced to zero. It records all 520 * the information needed to free the blocks of a file after its 521 * zero'ed inode has been written to disk. The actual work is done 522 * by child freework structures which are responsible for individual 523 * inode pointers while freeblks is responsible for retiring the 524 * entire operation when it is complete and holding common members. 525 */ 526struct freeblks { 527 struct worklist fb_list; /* id_inowait or delayed worklist */ 528# define fb_state fb_list.wk_state /* inode and dirty block state */ 529 TAILQ_ENTRY(freeblks) fb_next; /* List of inode truncates. */ 530 struct jblkdephd fb_jblkdephd; /* Journal entries pending */ 531 struct workhead fb_freeworkhd; /* Work items pending */ 532 struct workhead fb_jwork; /* Journal work pending */ 533 struct vnode *fb_devvp; /* filesystem device vnode */ 534#ifdef QUOTA 535 struct dquot *fb_quota[MAXQUOTAS]; /* quotas to be adjusted */ 536#endif 537 uint64_t fb_modrev; /* Inode revision at start of trunc. */ 538 off_t fb_len; /* Length we're truncating to. */ 539 ufs2_daddr_t fb_chkcnt; /* Blocks released. */ 540 ino_t fb_inum; /* inode owner of blocks */ 541 enum vtype fb_vtype; /* inode owner's file type */ 542 uid_t fb_uid; /* uid of previous owner of blocks */ 543 int fb_ref; /* Children outstanding. */ 544 int fb_cgwait; /* cg writes outstanding. */ 545}; 546 547/* 548 * A "freework" structure handles the release of a tree of blocks or a single 549 * block. Each indirect block in a tree is allocated its own freework 550 * structure so that the indirect block may be freed only when all of its 551 * children are freed. In this way we enforce the rule that an allocated 552 * block must have a valid path to a root that is journaled. Each child 553 * block acquires a reference and when the ref hits zero the parent ref 554 * is decremented. If there is no parent the freeblks ref is decremented. 555 */ 556struct freework { 557 struct worklist fw_list; /* Delayed worklist. */ 558# define fw_state fw_list.wk_state 559 LIST_ENTRY(freework) fw_segs; /* Seg list. */ 560 TAILQ_ENTRY(freework) fw_next; /* Hash/Trunc list. */ 561 struct jnewblk *fw_jnewblk; /* Journal entry to cancel. */ 562 struct freeblks *fw_freeblks; /* Root of operation. */ 563 struct freework *fw_parent; /* Parent indirect. */ 564 struct indirdep *fw_indir; /* indirect block. */ 565 ufs2_daddr_t fw_blkno; /* Our block #. */ 566 ufs_lbn_t fw_lbn; /* Original lbn before free. */ 567 uint16_t fw_frags; /* Number of frags. */ 568 uint16_t fw_ref; /* Number of children out. */ 569 uint16_t fw_off; /* Current working position. */ 570 uint16_t fw_start; /* Start of partial truncate. */ 571}; 572 573/* 574 * A "freedep" structure is allocated to track the completion of a bitmap 575 * write for a freework. One freedep may cover many freed blocks so long 576 * as they reside in the same cylinder group. When the cg is written 577 * the freedep decrements the ref on the freework which may permit it 578 * to be freed as well. 579 */ 580struct freedep { 581 struct worklist fd_list; /* Delayed worklist. */ 582 struct freework *fd_freework; /* Parent freework. */ 583}; 584 585/* 586 * A "freefile" structure is attached to an inode when its 587 * link count is reduced to zero. It marks the inode as free in 588 * the cylinder group map after the zero'ed inode has been written 589 * to disk and any associated blocks and fragments have been freed. 590 */ 591struct freefile { 592 struct worklist fx_list; /* id_inowait or delayed worklist */ 593 mode_t fx_mode; /* mode of inode */ 594 ino_t fx_oldinum; /* inum of the unlinked file */ 595 struct vnode *fx_devvp; /* filesystem device vnode */ 596 struct workhead fx_jwork; /* journal work pending. */ 597}; 598 599/* 600 * A "diradd" structure is linked to an "inodedep" id_inowait list when a 601 * new directory entry is allocated that references the inode described 602 * by "inodedep". When the inode itself is written (either the initial 603 * allocation for new inodes or with the increased link count for 604 * existing inodes), the COMPLETE flag is set in da_state. If the entry 605 * is for a newly allocated inode, the "inodedep" structure is associated 606 * with a bmsafemap which prevents the inode from being written to disk 607 * until the cylinder group has been updated. Thus the da_state COMPLETE 608 * flag cannot be set until the inode bitmap dependency has been removed. 609 * When creating a new file, it is safe to write the directory entry that 610 * claims the inode once the referenced inode has been written. Since 611 * writing the inode clears the bitmap dependencies, the DEPCOMPLETE flag 612 * in the diradd can be set unconditionally when creating a file. When 613 * creating a directory, there are two additional dependencies described by 614 * mkdir structures (see their description below). When these dependencies 615 * are resolved the DEPCOMPLETE flag is set in the diradd structure. 616 * If there are multiple links created to the same inode, there will be 617 * a separate diradd structure created for each link. The diradd is 618 * linked onto the pg_diraddhd list of the pagedep for the directory 619 * page that contains the entry. When a directory page is written, 620 * the pg_diraddhd list is traversed to rollback any entries that are 621 * not yet ready to be written to disk. If a directory entry is being 622 * changed (by rename) rather than added, the DIRCHG flag is set and 623 * the da_previous entry points to the entry that will be "removed" 624 * once the new entry has been committed. During rollback, entries 625 * with da_previous are replaced with the previous inode number rather 626 * than zero. 627 * 628 * The overlaying of da_pagedep and da_previous is done to keep the 629 * structure down. If a da_previous entry is present, the pointer to its 630 * pagedep is available in the associated dirrem entry. If the DIRCHG flag 631 * is set, the da_previous entry is valid; if not set the da_pagedep entry 632 * is valid. The DIRCHG flag never changes; it is set when the structure 633 * is created if appropriate and is never cleared. 634 */ 635struct diradd { 636 struct worklist da_list; /* id_inowait or id_pendinghd list */ 637# define da_state da_list.wk_state /* state of the new directory entry */ 638 LIST_ENTRY(diradd) da_pdlist; /* pagedep holding directory block */ 639 doff_t da_offset; /* offset of new dir entry in dir blk */ 640 ino_t da_newinum; /* inode number for the new dir entry */ 641 union { 642 struct dirrem *dau_previous; /* entry being replaced in dir change */ 643 struct pagedep *dau_pagedep; /* pagedep dependency for addition */ 644 } da_un; 645 struct workhead da_jwork; /* Journal work awaiting completion. */ 646}; 647#define da_previous da_un.dau_previous 648#define da_pagedep da_un.dau_pagedep 649 650/* 651 * Two "mkdir" structures are needed to track the additional dependencies 652 * associated with creating a new directory entry. Normally a directory 653 * addition can be committed as soon as the newly referenced inode has been 654 * written to disk with its increased link count. When a directory is 655 * created there are two additional dependencies: writing the directory 656 * data block containing the "." and ".." entries (MKDIR_BODY) and writing 657 * the parent inode with the increased link count for ".." (MKDIR_PARENT). 658 * These additional dependencies are tracked by two mkdir structures that 659 * reference the associated "diradd" structure. When they have completed, 660 * they set the DEPCOMPLETE flag on the diradd so that it knows that its 661 * extra dependencies have been completed. The md_state field is used only 662 * to identify which type of dependency the mkdir structure is tracking. 663 * It is not used in the mainline code for any purpose other than consistency 664 * checking. All the mkdir structures in the system are linked together on 665 * a list. This list is needed so that a diradd can find its associated 666 * mkdir structures and deallocate them if it is prematurely freed (as for 667 * example if a mkdir is immediately followed by a rmdir of the same directory). 668 * Here, the free of the diradd must traverse the list to find the associated 669 * mkdir structures that reference it. The deletion would be faster if the 670 * diradd structure were simply augmented to have two pointers that referenced 671 * the associated mkdir's. However, this would increase the size of the diradd 672 * structure to speed a very infrequent operation. 673 */ 674struct mkdir { 675 struct worklist md_list; /* id_inowait or buffer holding dir */ 676# define md_state md_list.wk_state /* type: MKDIR_PARENT or MKDIR_BODY */ 677 struct diradd *md_diradd; /* associated diradd */ 678 struct jaddref *md_jaddref; /* dependent jaddref. */ 679 struct buf *md_buf; /* MKDIR_BODY: buffer holding dir */ 680 LIST_ENTRY(mkdir) md_mkdirs; /* list of all mkdirs */ 681}; 682 683/* 684 * A "dirrem" structure describes an operation to decrement the link 685 * count on an inode. The dirrem structure is attached to the pg_dirremhd 686 * list of the pagedep for the directory page that contains the entry. 687 * It is processed after the directory page with the deleted entry has 688 * been written to disk. 689 */ 690struct dirrem { 691 struct worklist dm_list; /* delayed worklist */ 692# define dm_state dm_list.wk_state /* state of the old directory entry */ 693 LIST_ENTRY(dirrem) dm_next; /* pagedep's list of dirrem's */ 694 LIST_ENTRY(dirrem) dm_inonext; /* inodedep's list of dirrem's */ 695 struct jremrefhd dm_jremrefhd; /* Pending remove reference deps. */ 696 ino_t dm_oldinum; /* inum of the removed dir entry */ 697 doff_t dm_offset; /* offset of removed dir entry in blk */ 698 union { 699 struct pagedep *dmu_pagedep; /* pagedep dependency for remove */ 700 ino_t dmu_dirinum; /* parent inode number (for rmdir) */ 701 } dm_un; 702 struct workhead dm_jwork; /* Journal work awaiting completion. */ 703}; 704#define dm_pagedep dm_un.dmu_pagedep 705#define dm_dirinum dm_un.dmu_dirinum 706 707/* 708 * A "newdirblk" structure tracks the progress of a newly allocated 709 * directory block from its creation until it is claimed by its on-disk 710 * inode. When a block is allocated to a directory, an fsync of a file 711 * whose name is within that block must ensure not only that the block 712 * containing the file name has been written, but also that the on-disk 713 * inode references that block. When a new directory block is created, 714 * we allocate a newdirblk structure which is linked to the associated 715 * allocdirect (on its ad_newdirblk list). When the allocdirect has been 716 * satisfied, the newdirblk structure is moved to the inodedep id_bufwait 717 * list of its directory to await the inode being written. When the inode 718 * is written, the directory entries are fully committed and can be 719 * deleted from their pagedep->id_pendinghd and inodedep->id_pendinghd 720 * lists. Note that we could track directory blocks allocated to indirect 721 * blocks using a similar scheme with the allocindir structures. Rather 722 * than adding this level of complexity, we simply write those newly 723 * allocated indirect blocks synchronously as such allocations are rare. 724 * In the case of a new directory the . and .. links are tracked with 725 * a mkdir rather than a pagedep. In this case we track the mkdir 726 * so it can be released when it is written. A workhead is used 727 * to simplify canceling a mkdir that is removed by a subsequent dirrem. 728 */ 729struct newdirblk { 730 struct worklist db_list; /* id_inowait or pg_newdirblk */ 731# define db_state db_list.wk_state 732 struct pagedep *db_pagedep; /* associated pagedep */ 733 struct workhead db_mkdir; 734}; 735 736/* 737 * The inoref structure holds the elements common to jaddref and jremref 738 * so they may easily be queued in-order on the inodedep. 739 */ 740struct inoref { 741 struct worklist if_list; /* Journal pending or jseg entries. */ 742# define if_state if_list.wk_state 743 TAILQ_ENTRY(inoref) if_deps; /* Links for inodedep. */ 744 struct jsegdep *if_jsegdep; /* Will track our journal record. */ 745 off_t if_diroff; /* Directory offset. */ 746 ino_t if_ino; /* Inode number. */ 747 ino_t if_parent; /* Parent inode number. */ 748 nlink_t if_nlink; /* nlink before addition. */ 749 uint16_t if_mode; /* File mode, needed for IFMT. */ 750}; 751 752/* 753 * A "jaddref" structure tracks a new reference (link count) on an inode 754 * and prevents the link count increase and bitmap allocation until a 755 * journal entry can be written. Once the journal entry is written, 756 * the inode is put on the pendinghd of the bmsafemap and a diradd or 757 * mkdir entry is placed on the bufwait list of the inode. The DEPCOMPLETE 758 * flag is used to indicate that all of the required information for writing 759 * the journal entry is present. MKDIR_BODY and MKDIR_PARENT are used to 760 * differentiate . and .. links from regular file names. NEWBLOCK indicates 761 * a bitmap is still pending. If a new reference is canceled by a delete 762 * prior to writing the journal the jaddref write is canceled and the 763 * structure persists to prevent any disk-visible changes until it is 764 * ultimately released when the file is freed or the link is dropped again. 765 */ 766struct jaddref { 767 struct inoref ja_ref; /* see inoref above. */ 768# define ja_list ja_ref.if_list /* Jrnl pending, id_inowait, dm_jwork.*/ 769# define ja_state ja_ref.if_list.wk_state 770 LIST_ENTRY(jaddref) ja_bmdeps; /* Links for bmsafemap. */ 771 union { 772 struct diradd *jau_diradd; /* Pending diradd. */ 773 struct mkdir *jau_mkdir; /* MKDIR_{PARENT,BODY} */ 774 } ja_un; 775}; 776#define ja_diradd ja_un.jau_diradd 777#define ja_mkdir ja_un.jau_mkdir 778#define ja_diroff ja_ref.if_diroff 779#define ja_ino ja_ref.if_ino 780#define ja_parent ja_ref.if_parent 781#define ja_mode ja_ref.if_mode 782 783/* 784 * A "jremref" structure tracks a removed reference (unlink) on an 785 * inode and prevents the directory remove from proceeding until the 786 * journal entry is written. Once the journal has been written the remove 787 * may proceed as normal. 788 */ 789struct jremref { 790 struct inoref jr_ref; /* see inoref above. */ 791# define jr_list jr_ref.if_list /* Linked to softdep_journal_pending. */ 792# define jr_state jr_ref.if_list.wk_state 793 LIST_ENTRY(jremref) jr_deps; /* Links for dirrem. */ 794 struct dirrem *jr_dirrem; /* Back pointer to dirrem. */ 795}; 796 797/* 798 * A "jmvref" structure tracks a name relocations within the same 799 * directory block that occur as a result of directory compaction. 800 * It prevents the updated directory entry from being written to disk 801 * until the journal entry is written. Once the journal has been 802 * written the compacted directory may be written to disk. 803 */ 804struct jmvref { 805 struct worklist jm_list; /* Linked to softdep_journal_pending. */ 806 LIST_ENTRY(jmvref) jm_deps; /* Jmvref on pagedep. */ 807 struct pagedep *jm_pagedep; /* Back pointer to pagedep. */ 808 ino_t jm_parent; /* Containing directory inode number. */ 809 ino_t jm_ino; /* Inode number of our entry. */ 810 off_t jm_oldoff; /* Our old offset in directory. */ 811 off_t jm_newoff; /* Our new offset in directory. */ 812}; 813 814/* 815 * A "jnewblk" structure tracks a newly allocated block or fragment and 816 * prevents the direct or indirect block pointer as well as the cg bitmap 817 * from being written until it is logged. After it is logged the jsegdep 818 * is attached to the allocdirect or allocindir until the operation is 819 * completed or reverted. If the operation is reverted prior to the journal 820 * write the jnewblk structure is maintained to prevent the bitmaps from 821 * reaching the disk. Ultimately the jnewblk structure will be passed 822 * to the free routine as the in memory cg is modified back to the free 823 * state at which time it can be released. It may be held on any of the 824 * fx_jwork, fw_jwork, fb_jwork, ff_jwork, nb_jwork, or ir_jwork lists. 825 */ 826struct jnewblk { 827 struct worklist jn_list; /* See lists above. */ 828# define jn_state jn_list.wk_state 829 struct jsegdep *jn_jsegdep; /* Will track our journal record. */ 830 LIST_ENTRY(jnewblk) jn_deps; /* Jnewblks on sm_jnewblkhd. */ 831 struct worklist *jn_dep; /* Dependency to ref completed seg. */ 832 ufs_lbn_t jn_lbn; /* Lbn to which allocated. */ 833 ufs2_daddr_t jn_blkno; /* Blkno allocated */ 834 ino_t jn_ino; /* Ino to which allocated. */ 835 int jn_oldfrags; /* Previous fragments when extended. */ 836 int jn_frags; /* Number of fragments. */ 837}; 838 839/* 840 * A "jblkdep" structure tracks jfreeblk and jtrunc records attached to a 841 * freeblks structure. 842 */ 843struct jblkdep { 844 struct worklist jb_list; /* For softdep journal pending. */ 845 struct jsegdep *jb_jsegdep; /* Reference to the jseg. */ 846 struct freeblks *jb_freeblks; /* Back pointer to freeblks. */ 847 LIST_ENTRY(jblkdep) jb_deps; /* Dep list on freeblks. */ 848 849}; 850 851/* 852 * A "jfreeblk" structure tracks the journal write for freeing a block 853 * or tree of blocks. The block pointer must not be cleared in the inode 854 * or indirect prior to the jfreeblk being written to the journal. 855 */ 856struct jfreeblk { 857 struct jblkdep jf_dep; /* freeblks linkage. */ 858 ufs_lbn_t jf_lbn; /* Lbn from which blocks freed. */ 859 ufs2_daddr_t jf_blkno; /* Blkno being freed. */ 860 ino_t jf_ino; /* Ino from which blocks freed. */ 861 int jf_frags; /* Number of frags being freed. */ 862}; 863 864/* 865 * A "jfreefrag" tracks the freeing of a single block when a fragment is 866 * extended or an indirect page is replaced. It is not part of a larger 867 * freeblks operation. 868 */ 869struct jfreefrag { 870 struct worklist fr_list; /* Linked to softdep_journal_pending. */ 871# define fr_state fr_list.wk_state 872 struct jsegdep *fr_jsegdep; /* Will track our journal record. */ 873 struct freefrag *fr_freefrag; /* Back pointer to freefrag. */ 874 ufs_lbn_t fr_lbn; /* Lbn from which frag freed. */ 875 ufs2_daddr_t fr_blkno; /* Blkno being freed. */ 876 ino_t fr_ino; /* Ino from which frag freed. */ 877 int fr_frags; /* Size of frag being freed. */ 878}; 879 880/* 881 * A "jtrunc" journals the intent to truncate an inode's data or extent area. 882 */ 883struct jtrunc { 884 struct jblkdep jt_dep; /* freeblks linkage. */ 885 off_t jt_size; /* Final file size. */ 886 int jt_extsize; /* Final extent size. */ 887 ino_t jt_ino; /* Ino being truncated. */ 888}; 889 890/* 891 * A "jfsync" journals the completion of an fsync which invalidates earlier 892 * jtrunc records in the journal. 893 */ 894struct jfsync { 895 struct worklist jfs_list; /* For softdep journal pending. */ 896 off_t jfs_size; /* Sync file size. */ 897 int jfs_extsize; /* Sync extent size. */ 898 ino_t jfs_ino; /* ino being synced. */ 899}; 900 901/* 902 * A "jsegdep" structure tracks a single reference to a written journal 903 * segment so the journal space can be reclaimed when all dependencies 904 * have been written. It can hang off of id_inowait, dm_jwork, da_jwork, 905 * nb_jwork, ff_jwork, or fb_jwork lists. 906 */ 907struct jsegdep { 908 struct worklist jd_list; /* See above for lists. */ 909# define jd_state jd_list.wk_state 910 struct jseg *jd_seg; /* Our journal record. */ 911}; 912 913/* 914 * A "jseg" structure contains all of the journal records written in a 915 * single disk write. The jaddref and jremref structures are linked into 916 * js_entries so thay may be completed when the write completes. The 917 * js_entries also include the write dependency structures: jmvref, 918 * jnewblk, jfreeblk, jfreefrag, and jtrunc. The js_refs field counts 919 * the number of entries on the js_entries list. Thus there is a single 920 * jseg entry to describe each journal write. 921 */ 922struct jseg { 923 struct worklist js_list; /* b_deps link for journal */ 924# define js_state js_list.wk_state 925 struct workhead js_entries; /* Entries awaiting write */ 926 LIST_HEAD(, freework) js_indirs;/* List of indirects in this seg. */ 927 TAILQ_ENTRY(jseg) js_next; /* List of all unfinished segments. */ 928 struct jblocks *js_jblocks; /* Back pointer to block/seg list */ 929 struct buf *js_buf; /* Buffer while unwritten */ 930 uint64_t js_seq; /* Journal record sequence number. */ 931 uint64_t js_oldseq; /* Oldest valid sequence number. */ 932 int js_size; /* Size of journal record in bytes. */ 933 int js_cnt; /* Total items allocated. */ 934 int js_refs; /* Count of js_entries items. */ 935}; 936 937/* 938 * A 'sbdep' structure tracks the head of the free inode list and 939 * superblock writes. This makes sure the superblock is always pointing at 940 * the first possible unlinked inode for the suj recovery process. If a 941 * block write completes and we discover a new head is available the buf 942 * is dirtied and the dep is kept. See the description of the UNLINK* 943 * flags above for more details. 944 */ 945struct sbdep { 946 struct worklist sb_list; /* b_dep linkage */ 947 struct fs *sb_fs; /* Filesystem pointer within buf. */ 948 struct ufsmount *sb_ump; /* Our mount structure */ 949}; 950