1/* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright © 2001-2007 Red Hat, Inc. 5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org> 6 * 7 * Created by David Woodhouse <dwmw2@infradead.org> 8 * 9 * For licensing information, see the file 'LICENCE' in this directory. 10 * 11 */ 12 13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15#include <linux/kernel.h> 16#include <linux/sched.h> 17#include <linux/slab.h> 18#include <linux/vmalloc.h> 19#include <linux/mtd/mtd.h> 20#include "nodelist.h" 21 22static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, 23 struct jffs2_inode_cache *, struct jffs2_full_dirent **); 24 25static inline struct jffs2_inode_cache * 26first_inode_chain(int *i, struct jffs2_sb_info *c) 27{ 28 for (; *i < c->inocache_hashsize; (*i)++) { 29 if (c->inocache_list[*i]) 30 return c->inocache_list[*i]; 31 } 32 return NULL; 33} 34 35static inline struct jffs2_inode_cache * 36next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c) 37{ 38 /* More in this chain? */ 39 if (ic->next) 40 return ic->next; 41 (*i)++; 42 return first_inode_chain(i, c); 43} 44 45#define for_each_inode(i, c, ic) \ 46 for (i = 0, ic = first_inode_chain(&i, (c)); \ 47 ic; \ 48 ic = next_inode(&i, ic, (c))) 49 50 51static void jffs2_build_inode_pass1(struct jffs2_sb_info *c, 52 struct jffs2_inode_cache *ic, 53 int *dir_hardlinks) 54{ 55 struct jffs2_full_dirent *fd; 56 57 dbg_fsbuild("building directory inode #%u\n", ic->ino); 58 59 /* For each child, increase nlink */ 60 for(fd = ic->scan_dents; fd; fd = fd->next) { 61 struct jffs2_inode_cache *child_ic; 62 if (!fd->ino) 63 continue; 64 65 /* we can get high latency here with huge directories */ 66 67 child_ic = jffs2_get_ino_cache(c, fd->ino); 68 if (!child_ic) { 69 dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n", 70 fd->name, fd->ino, ic->ino); 71 jffs2_mark_node_obsolete(c, fd->raw); 72 /* Clear the ic/raw union so it doesn't cause problems later. */ 73 fd->ic = NULL; 74 continue; 75 } 76 77 /* From this point, fd->raw is no longer used so we can set fd->ic */ 78 fd->ic = child_ic; 79 child_ic->pino_nlink++; 80 /* If we appear (at this stage) to have hard-linked directories, 81 * set a flag to trigger a scan later */ 82 if (fd->type == DT_DIR) { 83 child_ic->flags |= INO_FLAGS_IS_DIR; 84 if (child_ic->pino_nlink > 1) 85 *dir_hardlinks = 1; 86 } 87 88 dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino); 89 /* Can't free scan_dents so far. We might need them in pass 2 */ 90 } 91} 92 93/* Scan plan: 94 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go 95 - Scan directory tree from top down, setting nlink in inocaches 96 - Scan inocaches for inodes with nlink==0 97*/ 98static int jffs2_build_filesystem(struct jffs2_sb_info *c) 99{ 100 int ret, i, dir_hardlinks = 0; 101 struct jffs2_inode_cache *ic; 102 struct jffs2_full_dirent *fd; 103 struct jffs2_full_dirent *dead_fds = NULL; 104 105 dbg_fsbuild("build FS data structures\n"); 106 107 /* First, scan the medium and build all the inode caches with 108 lists of physical nodes */ 109 110 c->flags |= JFFS2_SB_FLAG_SCANNING; 111 ret = jffs2_scan_medium(c); 112 c->flags &= ~JFFS2_SB_FLAG_SCANNING; 113 if (ret) 114 goto exit; 115 116 dbg_fsbuild("scanned flash completely\n"); 117 jffs2_dbg_dump_block_lists_nolock(c); 118 119 dbg_fsbuild("pass 1 starting\n"); 120 c->flags |= JFFS2_SB_FLAG_BUILDING; 121 /* Now scan the directory tree, increasing nlink according to every dirent found. */ 122 for_each_inode(i, c, ic) { 123 if (ic->scan_dents) { 124 jffs2_build_inode_pass1(c, ic, &dir_hardlinks); 125 cond_resched(); 126 } 127 } 128 129 dbg_fsbuild("pass 1 complete\n"); 130 131 /* Next, scan for inodes with nlink == 0 and remove them. If 132 they were directories, then decrement the nlink of their 133 children too, and repeat the scan. As that's going to be 134 a fairly uncommon occurrence, it's not so evil to do it this 135 way. Recursion bad. */ 136 dbg_fsbuild("pass 2 starting\n"); 137 138 for_each_inode(i, c, ic) { 139 if (ic->pino_nlink) 140 continue; 141 142 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 143 cond_resched(); 144 } 145 146 dbg_fsbuild("pass 2a starting\n"); 147 148 while (dead_fds) { 149 fd = dead_fds; 150 dead_fds = fd->next; 151 152 ic = jffs2_get_ino_cache(c, fd->ino); 153 154 if (ic) 155 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 156 jffs2_free_full_dirent(fd); 157 } 158 159 dbg_fsbuild("pass 2a complete\n"); 160 161 if (dir_hardlinks) { 162 /* If we detected directory hardlinks earlier, *hopefully* 163 * they are gone now because some of the links were from 164 * dead directories which still had some old dirents lying 165 * around and not yet garbage-collected, but which have 166 * been discarded above. So clear the pino_nlink field 167 * in each directory, so that the final scan below can 168 * print appropriate warnings. */ 169 for_each_inode(i, c, ic) { 170 if (ic->flags & INO_FLAGS_IS_DIR) 171 ic->pino_nlink = 0; 172 } 173 } 174 dbg_fsbuild("freeing temporary data structures\n"); 175 176 /* Finally, we can scan again and free the dirent structs */ 177 for_each_inode(i, c, ic) { 178 while(ic->scan_dents) { 179 fd = ic->scan_dents; 180 ic->scan_dents = fd->next; 181 /* We do use the pino_nlink field to count nlink of 182 * directories during fs build, so set it to the 183 * parent ino# now. Now that there's hopefully only 184 * one. */ 185 if (fd->type == DT_DIR) { 186 if (!fd->ic) { 187 /* We'll have complained about it and marked the coresponding 188 raw node obsolete already. Just skip it. */ 189 continue; 190 } 191 192 /* We *have* to have set this in jffs2_build_inode_pass1() */ 193 BUG_ON(!(fd->ic->flags & INO_FLAGS_IS_DIR)); 194 195 /* We clear ic->pino_nlink ∀ directories' ic *only* if dir_hardlinks 196 * is set. Otherwise, we know this should never trigger anyway, so 197 * we don't do the check. And ic->pino_nlink still contains the nlink 198 * value (which is 1). */ 199 if (dir_hardlinks && fd->ic->pino_nlink) { 200 JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u is also hard linked from dir ino #%u\n", 201 fd->name, fd->ino, ic->ino, fd->ic->pino_nlink); 202 /* Should we unlink it from its previous parent? */ 203 } 204 205 /* For directories, ic->pino_nlink holds that parent inode # */ 206 fd->ic->pino_nlink = ic->ino; 207 } 208 jffs2_free_full_dirent(fd); 209 } 210 ic->scan_dents = NULL; 211 cond_resched(); 212 } 213 jffs2_build_xattr_subsystem(c); 214 c->flags &= ~JFFS2_SB_FLAG_BUILDING; 215 216 dbg_fsbuild("FS build complete\n"); 217 218 /* Rotate the lists by some number to ensure wear levelling */ 219 jffs2_rotate_lists(c); 220 221 ret = 0; 222 223exit: 224 if (ret) { 225 for_each_inode(i, c, ic) { 226 while(ic->scan_dents) { 227 fd = ic->scan_dents; 228 ic->scan_dents = fd->next; 229 jffs2_free_full_dirent(fd); 230 } 231 } 232 jffs2_clear_xattr_subsystem(c); 233 } 234 235 return ret; 236} 237 238static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, 239 struct jffs2_inode_cache *ic, 240 struct jffs2_full_dirent **dead_fds) 241{ 242 struct jffs2_raw_node_ref *raw; 243 struct jffs2_full_dirent *fd; 244 245 dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino); 246 247 raw = ic->nodes; 248 while (raw != (void *)ic) { 249 struct jffs2_raw_node_ref *next = raw->next_in_ino; 250 dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw)); 251 jffs2_mark_node_obsolete(c, raw); 252 raw = next; 253 } 254 255 if (ic->scan_dents) { 256 int whinged = 0; 257 dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino); 258 259 while(ic->scan_dents) { 260 struct jffs2_inode_cache *child_ic; 261 262 fd = ic->scan_dents; 263 ic->scan_dents = fd->next; 264 265 if (!fd->ino) { 266 /* It's a deletion dirent. Ignore it */ 267 dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name); 268 jffs2_free_full_dirent(fd); 269 continue; 270 } 271 if (!whinged) 272 whinged = 1; 273 274 dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino); 275 276 child_ic = jffs2_get_ino_cache(c, fd->ino); 277 if (!child_ic) { 278 dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n", 279 fd->name, fd->ino); 280 jffs2_free_full_dirent(fd); 281 continue; 282 } 283 284 /* Reduce nlink of the child. If it's now zero, stick it on the 285 dead_fds list to be cleaned up later. Else just free the fd */ 286 child_ic->pino_nlink--; 287 288 if (!child_ic->pino_nlink) { 289 dbg_fsbuild("inode #%u (\"%s\") now has no links; adding to dead_fds list.\n", 290 fd->ino, fd->name); 291 fd->next = *dead_fds; 292 *dead_fds = fd; 293 } else { 294 dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n", 295 fd->ino, fd->name, child_ic->pino_nlink); 296 jffs2_free_full_dirent(fd); 297 } 298 } 299 } 300 301 /* 302 We don't delete the inocache from the hash list and free it yet. 303 The erase code will do that, when all the nodes are completely gone. 304 */ 305} 306 307static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c) 308{ 309 uint32_t size; 310 311 /* Deletion should almost _always_ be allowed. We're fairly 312 buggered once we stop allowing people to delete stuff 313 because there's not enough free space... */ 314 c->resv_blocks_deletion = 2; 315 316 /* Be conservative about how much space we need before we allow writes. 317 On top of that which is required for deletia, require an extra 2% 318 of the medium to be available, for overhead caused by nodes being 319 split across blocks, etc. */ 320 321 size = c->flash_size / 50; /* 2% of flash size */ 322 size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */ 323 size += c->sector_size - 1; /* ... and round up */ 324 325 c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size); 326 327 /* When do we let the GC thread run in the background */ 328 329 c->resv_blocks_gctrigger = c->resv_blocks_write + 1; 330 331 /* When do we allow garbage collection to merge nodes to make 332 long-term progress at the expense of short-term space exhaustion? */ 333 c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1; 334 335 /* When do we allow garbage collection to eat from bad blocks rather 336 than actually making progress? */ 337 c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2; 338 339 /* What number of 'very dirty' eraseblocks do we allow before we 340 trigger the GC thread even if we don't _need_ the space. When we 341 can't mark nodes obsolete on the medium, the old dirty nodes cause 342 performance problems because we have to inspect and discard them. */ 343 c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger; 344 if (jffs2_can_mark_obsolete(c)) 345 c->vdirty_blocks_gctrigger *= 10; 346 347 /* If there's less than this amount of dirty space, don't bother 348 trying to GC to make more space. It'll be a fruitless task */ 349 c->nospc_dirty_size = c->sector_size + (c->flash_size / 100); 350 351 dbg_fsbuild("trigger levels (size %d KiB, block size %d KiB, %d blocks)\n", 352 c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks); 353 dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n", 354 c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024); 355 dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n", 356 c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024); 357 dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n", 358 c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024); 359 dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n", 360 c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024); 361 dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n", 362 c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024); 363 dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n", 364 c->nospc_dirty_size); 365 dbg_fsbuild("Very dirty blocks before GC triggered: %d\n", 366 c->vdirty_blocks_gctrigger); 367} 368 369int jffs2_do_mount_fs(struct jffs2_sb_info *c) 370{ 371 int ret; 372 int i; 373 int size; 374 375 c->free_size = c->flash_size; 376 c->nr_blocks = c->flash_size / c->sector_size; 377 size = sizeof(struct jffs2_eraseblock) * c->nr_blocks; 378#ifndef __ECOS 379 if (jffs2_blocks_use_vmalloc(c)) 380 c->blocks = vzalloc(size); 381 else 382#endif 383 c->blocks = kzalloc(size, GFP_KERNEL); 384 if (!c->blocks) 385 return -ENOMEM; 386 387 for (i=0; i<c->nr_blocks; i++) { 388 INIT_LIST_HEAD(&c->blocks[i].list); 389 c->blocks[i].offset = i * c->sector_size; 390 c->blocks[i].free_size = c->sector_size; 391 } 392 393 INIT_LIST_HEAD(&c->clean_list); 394 INIT_LIST_HEAD(&c->very_dirty_list); 395 INIT_LIST_HEAD(&c->dirty_list); 396 INIT_LIST_HEAD(&c->erasable_list); 397 INIT_LIST_HEAD(&c->erasing_list); 398 INIT_LIST_HEAD(&c->erase_checking_list); 399 INIT_LIST_HEAD(&c->erase_pending_list); 400 INIT_LIST_HEAD(&c->erasable_pending_wbuf_list); 401 INIT_LIST_HEAD(&c->erase_complete_list); 402 INIT_LIST_HEAD(&c->free_list); 403 INIT_LIST_HEAD(&c->bad_list); 404 INIT_LIST_HEAD(&c->bad_used_list); 405 c->highest_ino = 1; 406 c->summary = NULL; 407 408 ret = jffs2_sum_init(c); 409 if (ret) 410 goto out_free; 411 412 if (jffs2_build_filesystem(c)) { 413 dbg_fsbuild("build_fs failed\n"); 414 jffs2_free_ino_caches(c); 415 jffs2_free_raw_node_refs(c); 416 ret = -EIO; 417 goto out_free; 418 } 419 420 jffs2_calc_trigger_levels(c); 421 422 return 0; 423 424 out_free: 425#ifndef __ECOS 426 if (jffs2_blocks_use_vmalloc(c)) 427 vfree(c->blocks); 428 else 429#endif 430 kfree(c->blocks); 431 432 return ret; 433} 434