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