fs/jffs2/build.c

   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 1.69 2004/12/16 20:22:18 dmarlin 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_MOUNTING;
 101         ret = jffs2_scan_medium(c);
 102         if (ret)
 103                 goto exit;
 104
 105         D1(printk(KERN_DEBUG "Scanned flash completely\n"));
 106         D2(jffs2_dump_block_lists(c));
 107
 108         /* Now scan the directory tree, increasing nlink according to every dirent found. */
 109         for_each_inode(i, c, ic) {
 110                 D1(printk(KERN_DEBUG "Pass 1: ino #%u\n", ic->ino));
 111
 112                 D1(BUG_ON(ic->ino > c->highest_ino));
 113
 114                 if (ic->scan_dents) {
 115                         jffs2_build_inode_pass1(c, ic);
 116                         cond_resched();
 117                 }
 118         }
 119         c->flags &= ~JFFS2_SB_FLAG_MOUNTING;
 120
 121         D1(printk(KERN_DEBUG "Pass 1 complete\n"));
 122
 123         /* Next, scan for inodes with nlink == 0 and remove them. If
 124            they were directories, then decrement the nlink of their
 125            children too, and repeat the scan. As that's going to be
 126            a fairly uncommon occurrence, it's not so evil to do it this
 127            way. Recursion bad. */
 128         D1(printk(KERN_DEBUG "Pass 2 starting\n"));
 129
 130         for_each_inode(i, c, ic) {
 131                 D1(printk(KERN_DEBUG "Pass 2: ino #%u, nlink %d, ic %p, nodes %p\n", ic->ino, ic->nlink, ic, ic->nodes));
 132                 if (ic->nlink)
 133                         continue;
 134
 135                 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
 136                 cond_resched();
 137         }
 138
 139         D1(printk(KERN_DEBUG "Pass 2a starting\n"));
 140
 141         while (dead_fds) {
 142                 fd = dead_fds;
 143                 dead_fds = fd->next;
 144
 145                 ic = jffs2_get_ino_cache(c, fd->ino);
 146                 D1(printk(KERN_DEBUG "Removing dead_fd ino #%u (\"%s\"), ic at %p\n", fd->ino, fd->name, ic));
 147
 148                 if (ic)
 149                         jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
 150                 jffs2_free_full_dirent(fd);
 151         }
 152
 153         D1(printk(KERN_DEBUG "Pass 2 complete\n"));
 154
 155         /* Finally, we can scan again and free the dirent structs */
 156         for_each_inode(i, c, ic) {
 157                 D1(printk(KERN_DEBUG "Pass 3: ino #%u, ic %p, nodes %p\n", ic->ino, ic, ic->nodes));
 158
 159                 while(ic->scan_dents) {
 160                         fd = ic->scan_dents;
 161                         ic->scan_dents = fd->next;
 162                         jffs2_free_full_dirent(fd);
 163                 }
 164                 ic->scan_dents = NULL;
 165                 cond_resched();
 166         }
 167         D1(printk(KERN_DEBUG "Pass 3 complete\n"));
 168         D2(jffs2_dump_block_lists(c));
 169
 170         /* Rotate the lists by some number to ensure wear levelling */
 171         jffs2_rotate_lists(c);
 172
 173         ret = 0;
 174
 175 exit:
 176         if (ret) {
 177                 for_each_inode(i, c, ic) {
 178                         while(ic->scan_dents) {
 179                                 fd = ic->scan_dents;
 180                                 ic->scan_dents = fd->next;
 181                                 jffs2_free_full_dirent(fd);
 182                         }
 183                 }
 184         }
 185
 186         return ret;
 187 }
 188
 189 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, struct jffs2_full_dirent **dead_fds)
 190 {
 191         struct jffs2_raw_node_ref *raw;
 192         struct jffs2_full_dirent *fd;
 193
 194         D1(printk(KERN_DEBUG "JFFS2: Removing ino #%u with nlink == zero.\n", ic->ino));
 195
 196         raw = ic->nodes;
 197         while (raw != (void *)ic) {
 198                 struct jffs2_raw_node_ref *next = raw->next_in_ino;
 199                 D1(printk(KERN_DEBUG "obsoleting node at 0x%08x\n", ref_offset(raw)));
 200                 jffs2_mark_node_obsolete(c, raw);
 201                 raw = next;
 202         }
 203
 204         if (ic->scan_dents) {
 205                 int whinged = 0;
 206                 D1(printk(KERN_DEBUG "Inode #%u was a directory which may have children...\n", ic->ino));
 207
 208                 while(ic->scan_dents) {
 209                         struct jffs2_inode_cache *child_ic;
 210
 211                         fd = ic->scan_dents;
 212                         ic->scan_dents = fd->next;
 213
 214                         if (!fd->ino) {
 215                                 /* It's a deletion dirent. Ignore it */
 216                                 D1(printk(KERN_DEBUG "Child \"%s\" is a deletion dirent, skipping...\n", fd->name));
 217                                 jffs2_free_full_dirent(fd);
 218                                 continue;
 219                         }
 220                         if (!whinged) {
 221                                 whinged = 1;
 222                                 printk(KERN_NOTICE "Inode #%u was a directory with children - removing those too...\n", ic->ino);
 223                         }
 224
 225                         D1(printk(KERN_DEBUG "Removing child \"%s\", ino #%u\n",
 226                                   fd->name, fd->ino));
 227
 228                         child_ic = jffs2_get_ino_cache(c, fd->ino);
 229                         if (!child_ic) {
 230                                 printk(KERN_NOTICE "Cannot remove child \"%s\", ino #%u, because it doesn't exist\n", fd->name, fd->ino);
 231                                 jffs2_free_full_dirent(fd);
 232                                 continue;
 233                         }
 234
 235                         /* Reduce nlink of the child. If it's now zero, stick it on the
 236                            dead_fds list to be cleaned up later. Else just free the fd */
 237
 238                         child_ic->nlink--;
 239
 240                         if (!child_ic->nlink) {
 241                                 D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got zero nlink. Adding to dead_fds list.\n",
 242                                           fd->ino, fd->name));
 243                                 fd->next = *dead_fds;
 244                                 *dead_fds = fd;
 245                         } else {
 246                                 D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
 247                                           fd->ino, fd->name, child_ic->nlink));
 248                                 jffs2_free_full_dirent(fd);
 249                         }
 250                 }
 251         }
 252
 253         /*
 254            We don't delete the inocache from the hash list and free it yet.
 255            The erase code will do that, when all the nodes are completely gone.
 256         */
 257 }
 258
 259 static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
 260 {
 261         uint32_t size;
 262
 263         /* Deletion should almost _always_ be allowed. We're fairly
 264            buggered once we stop allowing people to delete stuff
 265            because there's not enough free space... */
 266         c->resv_blocks_deletion = 2;
 267
 268         /* Be conservative about how much space we need before we allow writes.
 269            On top of that which is required for deletia, require an extra 2%
 270            of the medium to be available, for overhead caused by nodes being
 271            split across blocks, etc. */
 272
 273         size = c->flash_size / 50; /* 2% of flash size */
 274         size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
 275         size += c->sector_size - 1; /* ... and round up */
 276
 277         c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);
 278
 279         /* When do we let the GC thread run in the background */
 280
 281         c->resv_blocks_gctrigger = c->resv_blocks_write + 1;
 282
 283         /* When do we allow garbage collection to merge nodes to make
 284            long-term progress at the expense of short-term space exhaustion? */
 285         c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;
 286
 287         /* When do we allow garbage collection to eat from bad blocks rather
 288            than actually making progress? */
 289         c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
 290
 291         /* If there's less than this amount of dirty space, don't bother
 292            trying to GC to make more space. It'll be a fruitless task */
 293         c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
 294
 295         D1(printk(KERN_DEBUG "JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
 296                   c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks));
 297         D1(printk(KERN_DEBUG "Blocks required to allow deletion:    %d (%d KiB)\n",
 298                   c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024));
 299         D1(printk(KERN_DEBUG "Blocks required to allow writes:      %d (%d KiB)\n",
 300                   c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024));
 301         D1(printk(KERN_DEBUG "Blocks required to quiesce GC thread: %d (%d KiB)\n",
 302                   c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024));
 303         D1(printk(KERN_DEBUG "Blocks required to allow GC merges:   %d (%d KiB)\n",
 304                   c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024));
 305         D1(printk(KERN_DEBUG "Blocks required to GC bad blocks:     %d (%d KiB)\n",
 306                   c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024));
 307         D1(printk(KERN_DEBUG "Amount of dirty space required to GC: %d bytes\n",
 308                   c->nospc_dirty_size));
 309 }
 310
 311 int jffs2_do_mount_fs(struct jffs2_sb_info *c)
 312 {
 313         int i;
 314
 315         c->free_size = c->flash_size;
 316         c->nr_blocks = c->flash_size / c->sector_size;
 317         if (c->mtd->flags & MTD_NO_VIRTBLOCKS)
 318                 c->blocks = vmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks);
 319         else
 320                 c->blocks = kmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks, GFP_KERNEL);
 321         if (!c->blocks)
 322                 return -ENOMEM;
 323         for (i=0; i<c->nr_blocks; i++) {
 324                 INIT_LIST_HEAD(&c->blocks[i].list);
 325                 c->blocks[i].offset = i * c->sector_size;
 326                 c->blocks[i].free_size = c->sector_size;
 327                 c->blocks[i].dirty_size = 0;
 328                 c->blocks[i].wasted_size = 0;
 329                 c->blocks[i].unchecked_size = 0;
 330                 c->blocks[i].used_size = 0;
 331                 c->blocks[i].first_node = NULL;
 332                 c->blocks[i].last_node = NULL;
 333                 c->blocks[i].bad_count = 0;
 334         }
 335
 336         init_MUTEX(&c->alloc_sem);
 337         init_MUTEX(&c->erase_free_sem);
 338         init_waitqueue_head(&c->erase_wait);
 339         init_waitqueue_head(&c->inocache_wq);
 340         spin_lock_init(&c->erase_completion_lock);
 341         spin_lock_init(&c->inocache_lock);
 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
 356         if (jffs2_build_filesystem(c)) {
 357                 D1(printk(KERN_DEBUG "build_fs failed\n"));
 358                 jffs2_free_ino_caches(c);
 359                 jffs2_free_raw_node_refs(c);
 360                 if (c->mtd->flags & MTD_NO_VIRTBLOCKS) {
 361                         vfree(c->blocks);
 362                 } else {
 363                         kfree(c->blocks);
 364                 }
 365                 return -EIO;
 366         }
 367
 368         jffs2_calc_trigger_levels(c);
 369
 370         return 0;
 371 }