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