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