1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright (C) 2001-2003 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 * $Id: build.c,v 1.75 2005/07/22 10:32:07 dedekind Exp $ 11 * 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/sched.h> 16 #include <linux/slab.h> 17 #include <linux/vmalloc.h> 18 #include <linux/mtd/mtd.h> 19 #include "nodelist.h" 20 21 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, 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 < 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 inline void jffs2_build_inode_pass1(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic) 50 { 51 struct jffs2_full_dirent *fd; 52 53 D1(printk(KERN_DEBUG "jffs2_build_inode 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 /* XXX: Can get high latency here with huge directories */ 62 63 child_ic = jffs2_get_ino_cache(c, fd->ino); 64 if (!child_ic) { 65 printk(KERN_NOTICE "Eep. 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 printk(KERN_NOTICE "Child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n", fd->name, fd->ino, ic->ino); 73 if (fd->ino == 1 && ic->ino == 1) { 74 printk(KERN_NOTICE "This is mostly harmless, and probably caused by creating a JFFS2 image\n"); 75 printk(KERN_NOTICE "using a buggy version of mkfs.jffs2. Use at least v1.17.\n"); 76 } 77 /* What do we do about it? */ 78 } 79 D1(printk(KERN_DEBUG "Increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino)); 80 /* Can't free them. We might need them in pass 2 */ 81 } 82 } 83 84 /* Scan plan: 85 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go 86 - Scan directory tree from top down, setting nlink in inocaches 87 - Scan inocaches for inodes with nlink==0 88 */ 89 static int jffs2_build_filesystem(struct jffs2_sb_info *c) 90 { 91 int ret; 92 int i; 93 struct jffs2_inode_cache *ic; 94 struct jffs2_full_dirent *fd; 95 struct jffs2_full_dirent *dead_fds = NULL; 96 97 /* First, scan the medium and build all the inode caches with 98 lists of physical nodes */ 99 100 c->flags |= JFFS2_SB_FLAG_SCANNING; 101 ret = jffs2_scan_medium(c); 102 c->flags &= ~JFFS2_SB_FLAG_SCANNING; 103 if (ret) 104 goto exit; 105 106 D1(printk(KERN_DEBUG "Scanned flash completely\n")); 107 jffs2_dbg_dump_block_lists_nolock(c); 108 109 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 D1(printk(KERN_DEBUG "Pass 1: ino #%u\n", ic->ino)); 113 114 D1(BUG_ON(ic->ino > c->highest_ino)); 115 116 if (ic->scan_dents) { 117 jffs2_build_inode_pass1(c, ic); 118 cond_resched(); 119 } 120 } 121 122 D1(printk(KERN_DEBUG "Pass 1 complete\n")); 123 124 /* Next, scan for inodes with nlink == 0 and remove them. If 125 they were directories, then decrement the nlink of their 126 children too, and repeat the scan. As that's going to be 127 a fairly uncommon occurrence, it's not so evil to do it this 128 way. Recursion bad. */ 129 D1(printk(KERN_DEBUG "Pass 2 starting\n")); 130 131 for_each_inode(i, c, ic) { 132 D1(printk(KERN_DEBUG "Pass 2: ino #%u, nlink %d, ic %p, nodes %p\n", ic->ino, ic->nlink, ic, ic->nodes)); 133 if (ic->nlink) 134 continue; 135 136 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 137 cond_resched(); 138 } 139 140 D1(printk(KERN_DEBUG "Pass 2a starting\n")); 141 142 while (dead_fds) { 143 fd = dead_fds; 144 dead_fds = fd->next; 145 146 ic = jffs2_get_ino_cache(c, fd->ino); 147 D1(printk(KERN_DEBUG "Removing dead_fd ino #%u (\"%s\"), ic at %p\n", fd->ino, fd->name, ic)); 148 149 if (ic) 150 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 151 jffs2_free_full_dirent(fd); 152 } 153 154 D1(printk(KERN_DEBUG "Pass 2 complete\n")); 155 156 /* Finally, we can scan again and free the dirent structs */ 157 for_each_inode(i, c, ic) { 158 D1(printk(KERN_DEBUG "Pass 3: ino #%u, ic %p, nodes %p\n", ic->ino, ic, ic->nodes)); 159 160 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 c->flags &= ~JFFS2_SB_FLAG_BUILDING; 169 170 D1(printk(KERN_DEBUG "Pass 3 complete\n")); 171 jffs2_dbg_dump_block_lists_nolock(c); 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 } 188 189 return ret; 190 } 191 192 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, struct jffs2_full_dirent **dead_fds) 193 { 194 struct jffs2_raw_node_ref *raw; 195 struct jffs2_full_dirent *fd; 196 197 D1(printk(KERN_DEBUG "JFFS2: Removing ino #%u with nlink == zero.\n", ic->ino)); 198 199 raw = ic->nodes; 200 while (raw != (void *)ic) { 201 struct jffs2_raw_node_ref *next = raw->next_in_ino; 202 D1(printk(KERN_DEBUG "obsoleting node at 0x%08x\n", ref_offset(raw))); 203 jffs2_mark_node_obsolete(c, raw); 204 raw = next; 205 } 206 207 if (ic->scan_dents) { 208 int whinged = 0; 209 D1(printk(KERN_DEBUG "Inode #%u was a directory which may have children...\n", ic->ino)); 210 211 while(ic->scan_dents) { 212 struct jffs2_inode_cache *child_ic; 213 214 fd = ic->scan_dents; 215 ic->scan_dents = fd->next; 216 217 if (!fd->ino) { 218 /* It's a deletion dirent. Ignore it */ 219 D1(printk(KERN_DEBUG "Child \"%s\" is a deletion dirent, skipping...\n", fd->name)); 220 jffs2_free_full_dirent(fd); 221 continue; 222 } 223 if (!whinged) { 224 whinged = 1; 225 printk(KERN_NOTICE "Inode #%u was a directory with children - removing those too...\n", ic->ino); 226 } 227 228 D1(printk(KERN_DEBUG "Removing child \"%s\", ino #%u\n", 229 fd->name, fd->ino)); 230 231 child_ic = jffs2_get_ino_cache(c, fd->ino); 232 if (!child_ic) { 233 printk(KERN_NOTICE "Cannot remove child \"%s\", ino #%u, because it doesn't exist\n", fd->name, fd->ino); 234 jffs2_free_full_dirent(fd); 235 continue; 236 } 237 238 /* Reduce nlink of the child. If it's now zero, stick it on the 239 dead_fds list to be cleaned up later. Else just free the fd */ 240 241 child_ic->nlink--; 242 243 if (!child_ic->nlink) { 244 D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got zero nlink. Adding to dead_fds list.\n", 245 fd->ino, fd->name)); 246 fd->next = *dead_fds; 247 *dead_fds = fd; 248 } else { 249 D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got nlink %d. Ignoring.\n", 250 fd->ino, fd->name, child_ic->nlink)); 251 jffs2_free_full_dirent(fd); 252 } 253 } 254 } 255 256 /* 257 We don't delete the inocache from the hash list and free it yet. 258 The erase code will do that, when all the nodes are completely gone. 259 */ 260 } 261 262 static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c) 263 { 264 uint32_t size; 265 266 /* Deletion should almost _always_ be allowed. We're fairly 267 buggered once we stop allowing people to delete stuff 268 because there's not enough free space... */ 269 c->resv_blocks_deletion = 2; 270 271 /* Be conservative about how much space we need before we allow writes. 272 On top of that which is required for deletia, require an extra 2% 273 of the medium to be available, for overhead caused by nodes being 274 split across blocks, etc. */ 275 276 size = c->flash_size / 50; /* 2% of flash size */ 277 size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */ 278 size += c->sector_size - 1; /* ... and round up */ 279 280 c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size); 281 282 /* When do we let the GC thread run in the background */ 283 284 c->resv_blocks_gctrigger = c->resv_blocks_write + 1; 285 286 /* When do we allow garbage collection to merge nodes to make 287 long-term progress at the expense of short-term space exhaustion? */ 288 c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1; 289 290 /* When do we allow garbage collection to eat from bad blocks rather 291 than actually making progress? */ 292 c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2; 293 294 /* If there's less than this amount of dirty space, don't bother 295 trying to GC to make more space. It'll be a fruitless task */ 296 c->nospc_dirty_size = c->sector_size + (c->flash_size / 100); 297 298 D1(printk(KERN_DEBUG "JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n", 299 c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks)); 300 D1(printk(KERN_DEBUG "Blocks required to allow deletion: %d (%d KiB)\n", 301 c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024)); 302 D1(printk(KERN_DEBUG "Blocks required to allow writes: %d (%d KiB)\n", 303 c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024)); 304 D1(printk(KERN_DEBUG "Blocks required to quiesce GC thread: %d (%d KiB)\n", 305 c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024)); 306 D1(printk(KERN_DEBUG "Blocks required to allow GC merges: %d (%d KiB)\n", 307 c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024)); 308 D1(printk(KERN_DEBUG "Blocks required to GC bad blocks: %d (%d KiB)\n", 309 c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024)); 310 D1(printk(KERN_DEBUG "Amount of dirty space required to GC: %d bytes\n", 311 c->nospc_dirty_size)); 312 } 313 314 int jffs2_do_mount_fs(struct jffs2_sb_info *c) 315 { 316 int i; 317 318 c->free_size = c->flash_size; 319 c->nr_blocks = c->flash_size / c->sector_size; 320 if (c->mtd->flags & MTD_NO_VIRTBLOCKS) 321 c->blocks = vmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks); 322 else 323 c->blocks = kmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks, GFP_KERNEL); 324 if (!c->blocks) 325 return -ENOMEM; 326 for (i=0; i<c->nr_blocks; i++) { 327 INIT_LIST_HEAD(&c->blocks[i].list); 328 c->blocks[i].offset = i * c->sector_size; 329 c->blocks[i].free_size = c->sector_size; 330 c->blocks[i].dirty_size = 0; 331 c->blocks[i].wasted_size = 0; 332 c->blocks[i].unchecked_size = 0; 333 c->blocks[i].used_size = 0; 334 c->blocks[i].first_node = NULL; 335 c->blocks[i].last_node = NULL; 336 c->blocks[i].bad_count = 0; 337 } 338 339 INIT_LIST_HEAD(&c->clean_list); 340 INIT_LIST_HEAD(&c->very_dirty_list); 341 INIT_LIST_HEAD(&c->dirty_list); 342 INIT_LIST_HEAD(&c->erasable_list); 343 INIT_LIST_HEAD(&c->erasing_list); 344 INIT_LIST_HEAD(&c->erase_pending_list); 345 INIT_LIST_HEAD(&c->erasable_pending_wbuf_list); 346 INIT_LIST_HEAD(&c->erase_complete_list); 347 INIT_LIST_HEAD(&c->free_list); 348 INIT_LIST_HEAD(&c->bad_list); 349 INIT_LIST_HEAD(&c->bad_used_list); 350 c->highest_ino = 1; 351 352 if (jffs2_build_filesystem(c)) { 353 D1(printk(KERN_DEBUG "build_fs failed\n")); 354 jffs2_free_ino_caches(c); 355 jffs2_free_raw_node_refs(c); 356 if (c->mtd->flags & MTD_NO_VIRTBLOCKS) { 357 vfree(c->blocks); 358 } else { 359 kfree(c->blocks); 360 } 361 return -EIO; 362 } 363 364 jffs2_calc_trigger_levels(c); 365 366 return 0; 367 } 368