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 1.71 2005/07/12 16:37:08 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         D2(jffs2_dump_block_lists(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         D2(jffs2_dump_block_lists(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 }