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 1.85 2005/11/07 11:14:38 gleixner 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 *, 22 struct jffs2_inode_cache *, struct jffs2_full_dirent **); 23 24 static inline struct jffs2_inode_cache * 25 first_inode_chain(int *i, struct jffs2_sb_info *c) 26 { 27 for (; *i < INOCACHE_HASHSIZE; (*i)++) { 28 if (c->inocache_list[*i]) 29 return c->inocache_list[*i]; 30 } 31 return NULL; 32 } 33 34 static inline struct jffs2_inode_cache * 35 next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c) 36 { 37 /* More in this chain? */ 38 if (ic->next) 39 return ic->next; 40 (*i)++; 41 return first_inode_chain(i, c); 42 } 43 44 #define for_each_inode(i, c, ic) \ 45 for (i = 0, ic = first_inode_chain(&i, (c)); \ 46 ic; \ 47 ic = next_inode(&i, ic, (c))) 48 49 50 static void jffs2_build_inode_pass1(struct jffs2_sb_info *c, 51 struct jffs2_inode_cache *ic) 52 { 53 struct jffs2_full_dirent *fd; 54 55 dbg_fsbuild("building directory inode #%u\n", ic->ino); 56 57 /* For each child, increase nlink */ 58 for(fd = ic->scan_dents; fd; fd = fd->next) { 59 struct jffs2_inode_cache *child_ic; 60 if (!fd->ino) 61 continue; 62 63 /* we can get high latency here with huge directories */ 64 65 child_ic = jffs2_get_ino_cache(c, fd->ino); 66 if (!child_ic) { 67 dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n", 68 fd->name, fd->ino, ic->ino); 69 jffs2_mark_node_obsolete(c, fd->raw); 70 continue; 71 } 72 73 if (child_ic->nlink++ && fd->type == DT_DIR) { 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 } 78 dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino); 79 /* Can't free scan_dents so far. We might need them in pass 2 */ 80 } 81 } 82 83 /* Scan plan: 84 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go 85 - Scan directory tree from top down, setting nlink in inocaches 86 - Scan inocaches for inodes with nlink==0 87 */ 88 static int jffs2_build_filesystem(struct jffs2_sb_info *c) 89 { 90 int ret; 91 int i; 92 struct jffs2_inode_cache *ic; 93 struct jffs2_full_dirent *fd; 94 struct jffs2_full_dirent *dead_fds = NULL; 95 96 dbg_fsbuild("build FS data structures\n"); 97 98 /* First, scan the medium and build all the inode caches with 99 lists of physical nodes */ 100 101 c->flags |= JFFS2_SB_FLAG_SCANNING; 102 ret = jffs2_scan_medium(c); 103 c->flags &= ~JFFS2_SB_FLAG_SCANNING; 104 if (ret) 105 goto exit; 106 107 dbg_fsbuild("scanned flash completely\n"); 108 jffs2_dbg_dump_block_lists_nolock(c); 109 110 dbg_fsbuild("pass 1 starting\n"); 111 c->flags |= JFFS2_SB_FLAG_BUILDING; 112 /* Now scan the directory tree, increasing nlink according to every dirent found. */ 113 for_each_inode(i, c, ic) { 114 if (ic->scan_dents) { 115 jffs2_build_inode_pass1(c, ic); 116 cond_resched(); 117 } 118 } 119 120 dbg_fsbuild("pass 1 complete\n"); 121 122 /* Next, scan for inodes with nlink == 0 and remove them. If 123 they were directories, then decrement the nlink of their 124 children too, and repeat the scan. As that's going to be 125 a fairly uncommon occurrence, it's not so evil to do it this 126 way. Recursion bad. */ 127 dbg_fsbuild("pass 2 starting\n"); 128 129 for_each_inode(i, c, ic) { 130 if (ic->nlink) 131 continue; 132 133 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 134 cond_resched(); 135 } 136 137 dbg_fsbuild("pass 2a starting\n"); 138 139 while (dead_fds) { 140 fd = dead_fds; 141 dead_fds = fd->next; 142 143 ic = jffs2_get_ino_cache(c, fd->ino); 144 145 if (ic) 146 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); 147 jffs2_free_full_dirent(fd); 148 } 149 150 dbg_fsbuild("pass 2a complete\n"); 151 dbg_fsbuild("freeing temporary data structures\n"); 152 153 /* Finally, we can scan again and free the dirent structs */ 154 for_each_inode(i, c, ic) { 155 while(ic->scan_dents) { 156 fd = ic->scan_dents; 157 ic->scan_dents = fd->next; 158 jffs2_free_full_dirent(fd); 159 } 160 ic->scan_dents = NULL; 161 cond_resched(); 162 } 163 c->flags &= ~JFFS2_SB_FLAG_BUILDING; 164 165 dbg_fsbuild("FS build complete\n"); 166 167 /* Rotate the lists by some number to ensure wear levelling */ 168 jffs2_rotate_lists(c); 169 170 ret = 0; 171 172 exit: 173 if (ret) { 174 for_each_inode(i, c, ic) { 175 while(ic->scan_dents) { 176 fd = ic->scan_dents; 177 ic->scan_dents = fd->next; 178 jffs2_free_full_dirent(fd); 179 } 180 } 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 /* If there's less than this amount of dirty space, don't bother 289 trying to GC to make more space. It'll be a fruitless task */ 290 c->nospc_dirty_size = c->sector_size + (c->flash_size / 100); 291 292 dbg_fsbuild("JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n", 293 c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks); 294 dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n", 295 c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024); 296 dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n", 297 c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024); 298 dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n", 299 c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024); 300 dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n", 301 c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024); 302 dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n", 303 c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024); 304 dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n", 305 c->nospc_dirty_size); 306 } 307 308 int jffs2_do_mount_fs(struct jffs2_sb_info *c) 309 { 310 int ret; 311 int i; 312 int size; 313 314 c->free_size = c->flash_size; 315 c->nr_blocks = c->flash_size / c->sector_size; 316 size = sizeof(struct jffs2_eraseblock) * c->nr_blocks; 317 #ifndef __ECOS 318 if (jffs2_blocks_use_vmalloc(c)) 319 c->blocks = vmalloc(size); 320 else 321 #endif 322 c->blocks = kmalloc(size, GFP_KERNEL); 323 if (!c->blocks) 324 return -ENOMEM; 325 326 memset(c->blocks, 0, size); 327 for (i=0; i<c->nr_blocks; i++) { 328 INIT_LIST_HEAD(&c->blocks[i].list); 329 c->blocks[i].offset = i * c->sector_size; 330 c->blocks[i].free_size = c->sector_size; 331 } 332 333 INIT_LIST_HEAD(&c->clean_list); 334 INIT_LIST_HEAD(&c->very_dirty_list); 335 INIT_LIST_HEAD(&c->dirty_list); 336 INIT_LIST_HEAD(&c->erasable_list); 337 INIT_LIST_HEAD(&c->erasing_list); 338 INIT_LIST_HEAD(&c->erase_pending_list); 339 INIT_LIST_HEAD(&c->erasable_pending_wbuf_list); 340 INIT_LIST_HEAD(&c->erase_complete_list); 341 INIT_LIST_HEAD(&c->free_list); 342 INIT_LIST_HEAD(&c->bad_list); 343 INIT_LIST_HEAD(&c->bad_used_list); 344 c->highest_ino = 1; 345 c->summary = NULL; 346 347 ret = jffs2_sum_init(c); 348 if (ret) 349 return ret; 350 351 if (jffs2_build_filesystem(c)) { 352 dbg_fsbuild("build_fs failed\n"); 353 jffs2_free_ino_caches(c); 354 jffs2_free_raw_node_refs(c); 355 #ifndef __ECOS 356 if (jffs2_blocks_use_vmalloc(c)) 357 vfree(c->blocks); 358 else 359 #endif 360 kfree(c->blocks); 361 362 return -EIO; 363 } 364 365 jffs2_calc_trigger_levels(c); 366 367 return 0; 368 } 369