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 22 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, 23 struct jffs2_inode_cache *, struct jffs2_full_dirent **); 24 25 static inline struct jffs2_inode_cache * 26 first_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 35 static inline struct jffs2_inode_cache * 36 next_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 51 static void jffs2_build_inode_pass1(struct jffs2_sb_info *c, 52 struct jffs2_inode_cache *ic) 53 { 54 struct jffs2_full_dirent *fd; 55 56 dbg_fsbuild("building directory inode #%u\n", ic->ino); 57 58 /* For each child, increase nlink */ 59 for(fd = ic->scan_dents; fd; fd = fd->next) { 60 struct jffs2_inode_cache *child_ic; 61 if (!fd->ino) 62 continue; 63 64 /* we can get high latency here with huge directories */ 65 66 child_ic = jffs2_get_ino_cache(c, fd->ino); 67 if (!child_ic) { 68 dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n", 69 fd->name, fd->ino, ic->ino); 70 jffs2_mark_node_obsolete(c, fd->raw); 71 continue; 72 } 73 74 if (fd->type == DT_DIR) { 75 if (child_ic->pino_nlink) { 76 JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n", 77 fd->name, fd->ino, ic->ino); 78 /* TODO: What do we do about it? */ 79 } else { 80 child_ic->pino_nlink = ic->ino; 81 } 82 } else 83 child_ic->pino_nlink++; 84 85 dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino); 86 /* Can't free scan_dents so far. We might need them in pass 2 */ 87 } 88 } 89 90 /* Scan plan: 91 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go 92 - Scan directory tree from top down, setting nlink in inocaches 93 - Scan inocaches for inodes with nlink==0 94 */ 95 static int jffs2_build_filesystem(struct jffs2_sb_info *c) 96 { 97 int ret; 98 int i; 99 struct jffs2_inode_cache *ic; 100 struct jffs2_full_dirent *fd; 101 struct jffs2_full_dirent *dead_fds = NULL; 102 103 dbg_fsbuild("build FS data structures\n"); 104 105 /* First, scan the medium and build all the inode caches with 106 lists of physical nodes */ 107 108 c->flags |= JFFS2_SB_FLAG_SCANNING; 109 ret = jffs2_scan_medium(c); 110 c->flags &= ~JFFS2_SB_FLAG_SCANNING; 111 if (ret) 112 goto exit; 113 114 dbg_fsbuild("scanned flash completely\n"); 115 jffs2_dbg_dump_block_lists_nolock(c); 116 117 dbg_fsbuild("pass 1 starting\n"); 118 c->flags |= JFFS2_SB_FLAG_BUILDING; 119 /* Now scan the directory tree, increasing nlink according to every dirent found. */ 120 for_each_inode(i, c, ic) { 121 if (ic->scan_dents) { 122 jffs2_build_inode_pass1(c, ic); 123 cond_resched(); 124 } 125 } 126 127 dbg_fsbuild("pass 1 complete\n"); 128 129 /* Next, scan for inodes with nlink == 0 and remove them. If 130 they were directories, then decrement the nlink of their 131 children too, and repeat the scan. As that's going to be 132 a fairly uncommon occurrence, it's not so evil to do it this 133 way. Recursion bad. */ 134 dbg_fsbuild("pass 2 starting\n"); 135 136 for_each_inode(i, c, ic) { 137 if (ic->pino_nlink) 138 continue; 139 140 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 141 cond_resched(); 142 } 143 144 dbg_fsbuild("pass 2a starting\n"); 145 146 while (dead_fds) { 147 fd = dead_fds; 148 dead_fds = fd->next; 149 150 ic = jffs2_get_ino_cache(c, fd->ino); 151 152 if (ic) 153 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 154 jffs2_free_full_dirent(fd); 155 } 156 157 dbg_fsbuild("pass 2a complete\n"); 158 dbg_fsbuild("freeing temporary data structures\n"); 159 160 /* Finally, we can scan again and free the dirent structs */ 161 for_each_inode(i, c, ic) { 162 while(ic->scan_dents) { 163 fd = ic->scan_dents; 164 ic->scan_dents = fd->next; 165 jffs2_free_full_dirent(fd); 166 } 167 ic->scan_dents = NULL; 168 cond_resched(); 169 } 170 jffs2_build_xattr_subsystem(c); 171 c->flags &= ~JFFS2_SB_FLAG_BUILDING; 172 173 dbg_fsbuild("FS build complete\n"); 174 175 /* Rotate the lists by some number to ensure wear levelling */ 176 jffs2_rotate_lists(c); 177 178 ret = 0; 179 180 exit: 181 if (ret) { 182 for_each_inode(i, c, ic) { 183 while(ic->scan_dents) { 184 fd = ic->scan_dents; 185 ic->scan_dents = fd->next; 186 jffs2_free_full_dirent(fd); 187 } 188 } 189 jffs2_clear_xattr_subsystem(c); 190 } 191 192 return ret; 193 } 194 195 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, 196 struct jffs2_inode_cache *ic, 197 struct jffs2_full_dirent **dead_fds) 198 { 199 struct jffs2_raw_node_ref *raw; 200 struct jffs2_full_dirent *fd; 201 202 dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino); 203 204 raw = ic->nodes; 205 while (raw != (void *)ic) { 206 struct jffs2_raw_node_ref *next = raw->next_in_ino; 207 dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw)); 208 jffs2_mark_node_obsolete(c, raw); 209 raw = next; 210 } 211 212 if (ic->scan_dents) { 213 int whinged = 0; 214 dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino); 215 216 while(ic->scan_dents) { 217 struct jffs2_inode_cache *child_ic; 218 219 fd = ic->scan_dents; 220 ic->scan_dents = fd->next; 221 222 if (!fd->ino) { 223 /* It's a deletion dirent. Ignore it */ 224 dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name); 225 jffs2_free_full_dirent(fd); 226 continue; 227 } 228 if (!whinged) 229 whinged = 1; 230 231 dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino); 232 233 child_ic = jffs2_get_ino_cache(c, fd->ino); 234 if (!child_ic) { 235 dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n", 236 fd->name, fd->ino); 237 jffs2_free_full_dirent(fd); 238 continue; 239 } 240 241 /* Reduce nlink of the child. If it's now zero, stick it on the 242 dead_fds list to be cleaned up later. Else just free the fd */ 243 244 if (fd->type == DT_DIR) 245 child_ic->pino_nlink = 0; 246 else 247 child_ic->pino_nlink--; 248 249 if (!child_ic->pino_nlink) { 250 dbg_fsbuild("inode #%u (\"%s\") now has no links; adding to dead_fds list.\n", 251 fd->ino, fd->name); 252 fd->next = *dead_fds; 253 *dead_fds = fd; 254 } else { 255 dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n", 256 fd->ino, fd->name, child_ic->pino_nlink); 257 jffs2_free_full_dirent(fd); 258 } 259 } 260 } 261 262 /* 263 We don't delete the inocache from the hash list and free it yet. 264 The erase code will do that, when all the nodes are completely gone. 265 */ 266 } 267 268 static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c) 269 { 270 uint32_t size; 271 272 /* Deletion should almost _always_ be allowed. We're fairly 273 buggered once we stop allowing people to delete stuff 274 because there's not enough free space... */ 275 c->resv_blocks_deletion = 2; 276 277 /* Be conservative about how much space we need before we allow writes. 278 On top of that which is required for deletia, require an extra 2% 279 of the medium to be available, for overhead caused by nodes being 280 split across blocks, etc. */ 281 282 size = c->flash_size / 50; /* 2% of flash size */ 283 size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */ 284 size += c->sector_size - 1; /* ... and round up */ 285 286 c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size); 287 288 /* When do we let the GC thread run in the background */ 289 290 c->resv_blocks_gctrigger = c->resv_blocks_write + 1; 291 292 /* When do we allow garbage collection to merge nodes to make 293 long-term progress at the expense of short-term space exhaustion? */ 294 c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1; 295 296 /* When do we allow garbage collection to eat from bad blocks rather 297 than actually making progress? */ 298 c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2; 299 300 /* What number of 'very dirty' eraseblocks do we allow before we 301 trigger the GC thread even if we don't _need_ the space. When we 302 can't mark nodes obsolete on the medium, the old dirty nodes cause 303 performance problems because we have to inspect and discard them. */ 304 c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger; 305 if (jffs2_can_mark_obsolete(c)) 306 c->vdirty_blocks_gctrigger *= 10; 307 308 /* If there's less than this amount of dirty space, don't bother 309 trying to GC to make more space. It'll be a fruitless task */ 310 c->nospc_dirty_size = c->sector_size + (c->flash_size / 100); 311 312 dbg_fsbuild("trigger levels (size %d KiB, block size %d KiB, %d blocks)\n", 313 c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks); 314 dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n", 315 c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024); 316 dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n", 317 c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024); 318 dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n", 319 c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024); 320 dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n", 321 c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024); 322 dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n", 323 c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024); 324 dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n", 325 c->nospc_dirty_size); 326 dbg_fsbuild("Very dirty blocks before GC triggered: %d\n", 327 c->vdirty_blocks_gctrigger); 328 } 329 330 int jffs2_do_mount_fs(struct jffs2_sb_info *c) 331 { 332 int ret; 333 int i; 334 int size; 335 336 c->free_size = c->flash_size; 337 c->nr_blocks = c->flash_size / c->sector_size; 338 size = sizeof(struct jffs2_eraseblock) * c->nr_blocks; 339 #ifndef __ECOS 340 if (jffs2_blocks_use_vmalloc(c)) 341 c->blocks = vzalloc(size); 342 else 343 #endif 344 c->blocks = kzalloc(size, GFP_KERNEL); 345 if (!c->blocks) 346 return -ENOMEM; 347 348 for (i=0; i<c->nr_blocks; i++) { 349 INIT_LIST_HEAD(&c->blocks[i].list); 350 c->blocks[i].offset = i * c->sector_size; 351 c->blocks[i].free_size = c->sector_size; 352 } 353 354 INIT_LIST_HEAD(&c->clean_list); 355 INIT_LIST_HEAD(&c->very_dirty_list); 356 INIT_LIST_HEAD(&c->dirty_list); 357 INIT_LIST_HEAD(&c->erasable_list); 358 INIT_LIST_HEAD(&c->erasing_list); 359 INIT_LIST_HEAD(&c->erase_checking_list); 360 INIT_LIST_HEAD(&c->erase_pending_list); 361 INIT_LIST_HEAD(&c->erasable_pending_wbuf_list); 362 INIT_LIST_HEAD(&c->erase_complete_list); 363 INIT_LIST_HEAD(&c->free_list); 364 INIT_LIST_HEAD(&c->bad_list); 365 INIT_LIST_HEAD(&c->bad_used_list); 366 c->highest_ino = 1; 367 c->summary = NULL; 368 369 ret = jffs2_sum_init(c); 370 if (ret) 371 goto out_free; 372 373 if (jffs2_build_filesystem(c)) { 374 dbg_fsbuild("build_fs failed\n"); 375 jffs2_free_ino_caches(c); 376 jffs2_free_raw_node_refs(c); 377 ret = -EIO; 378 goto out_free; 379 } 380 381 jffs2_calc_trigger_levels(c); 382 383 return 0; 384 385 out_free: 386 #ifndef __ECOS 387 if (jffs2_blocks_use_vmalloc(c)) 388 vfree(c->blocks); 389 else 390 #endif 391 kfree(c->blocks); 392 393 return ret; 394 } 395