release/src-rt-6.x.4708/linux/linux-2.6.36/fs/ufs/ialloc.c

   1 /*
   2  *  linux/fs/ufs/ialloc.c
   3  *
   4  * Copyright (c) 1998
   5  * Daniel Pirkl <daniel.pirkl@email.cz>
   6  * Charles University, Faculty of Mathematics and Physics
   7  *
   8  *  from
   9  *
  10  *  linux/fs/ext2/ialloc.c
  11  *
  12  * Copyright (C) 1992, 1993, 1994, 1995
  13  * Remy Card (card@masi.ibp.fr)
  14  * Laboratoire MASI - Institut Blaise Pascal
  15  * Universite Pierre et Marie Curie (Paris VI)
  16  *
  17  *  BSD ufs-inspired inode and directory allocation by
  18  *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
  19  *  Big-endian to little-endian byte-swapping/bitmaps by
  20  *        David S. Miller (davem@caip.rutgers.edu), 1995
  21  *
  22  * UFS2 write support added by
  23  * Evgeniy Dushistov <dushistov@mail.ru>, 2007
  24  */
  25
  26 #include <linux/fs.h>
  27 #include <linux/time.h>
  28 #include <linux/stat.h>
  29 #include <linux/string.h>
  30 #include <linux/buffer_head.h>
  31 #include <linux/sched.h>
  32 #include <linux/bitops.h>
  33 #include <asm/byteorder.h>
  34
  35 #include "ufs_fs.h"
  36 #include "ufs.h"
  37 #include "swab.h"
  38 #include "util.h"
  39
  40 /*
  41  * NOTE! When we get the inode, we're the only people
  42  * that have access to it, and as such there are no
  43  * race conditions we have to worry about. The inode
  44  * is not on the hash-lists, and it cannot be reached
  45  * through the filesystem because the directory entry
  46  * has been deleted earlier.
  47  *
  48  * HOWEVER: we must make sure that we get no aliases,
  49  * which means that we have to call "clear_inode()"
  50  * _before_ we mark the inode not in use in the inode
  51  * bitmaps. Otherwise a newly created file might use
  52  * the same inode number (not actually the same pointer
  53  * though), and then we'd have two inodes sharing the
  54  * same inode number and space on the harddisk.
  55  */
  56 void ufs_free_inode (struct inode * inode)
  57 {
  58         struct super_block * sb;
  59         struct ufs_sb_private_info * uspi;
  60         struct ufs_super_block_first * usb1;
  61         struct ufs_cg_private_info * ucpi;
  62         struct ufs_cylinder_group * ucg;
  63         int is_directory;
  64         unsigned ino, cg, bit;
  65
  66         UFSD("ENTER, ino %lu\n", inode->i_ino);
  67
  68         sb = inode->i_sb;
  69         uspi = UFS_SB(sb)->s_uspi;
  70         usb1 = ubh_get_usb_first(uspi);
  71
  72         ino = inode->i_ino;
  73
  74         lock_super (sb);
  75
  76         if (!((ino > 1) && (ino < (uspi->s_ncg * uspi->s_ipg )))) {
  77                 ufs_warning(sb, "ufs_free_inode", "reserved inode or nonexistent inode %u\n", ino);
  78                 unlock_super (sb);
  79                 return;
  80         }
  81
  82         cg = ufs_inotocg (ino);
  83         bit = ufs_inotocgoff (ino);
  84         ucpi = ufs_load_cylinder (sb, cg);
  85         if (!ucpi) {
  86                 unlock_super (sb);
  87                 return;
  88         }
  89         ucg = ubh_get_ucg(UCPI_UBH(ucpi));
  90         if (!ufs_cg_chkmagic(sb, ucg))
  91                 ufs_panic (sb, "ufs_free_fragments", "internal error, bad cg magic number");
  92
  93         ucg->cg_time = cpu_to_fs32(sb, get_seconds());
  94
  95         is_directory = S_ISDIR(inode->i_mode);
  96
  97         if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
  98                 ufs_error(sb, "ufs_free_inode", "bit already cleared for inode %u", ino);
  99         else {
 100                 ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
 101                 if (ino < ucpi->c_irotor)
 102                         ucpi->c_irotor = ino;
 103                 fs32_add(sb, &ucg->cg_cs.cs_nifree, 1);
 104                 uspi->cs_total.cs_nifree++;
 105                 fs32_add(sb, &UFS_SB(sb)->fs_cs(cg).cs_nifree, 1);
 106
 107                 if (is_directory) {
 108                         fs32_sub(sb, &ucg->cg_cs.cs_ndir, 1);
 109                         uspi->cs_total.cs_ndir--;
 110                         fs32_sub(sb, &UFS_SB(sb)->fs_cs(cg).cs_ndir, 1);
 111                 }
 112         }
 113
 114         ubh_mark_buffer_dirty (USPI_UBH(uspi));
 115         ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
 116         if (sb->s_flags & MS_SYNCHRONOUS)
 117                 ubh_sync_block(UCPI_UBH(ucpi));
 118
 119         sb->s_dirt = 1;
 120         unlock_super (sb);
 121         UFSD("EXIT\n");
 122 }
 123
 124 /*
 125  * Nullify new chunk of inodes,
 126  * BSD people also set ui_gen field of inode
 127  * during nullification, but we not care about
 128  * that because of linux ufs do not support NFS
 129  */
 130 static void ufs2_init_inodes_chunk(struct super_block *sb,
 131                                    struct ufs_cg_private_info *ucpi,
 132                                    struct ufs_cylinder_group *ucg)
 133 {
 134         struct buffer_head *bh;
 135         struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
 136         sector_t beg = uspi->s_sbbase +
 137                 ufs_inotofsba(ucpi->c_cgx * uspi->s_ipg +
 138                               fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk));
 139         sector_t end = beg + uspi->s_fpb;
 140
 141         UFSD("ENTER cgno %d\n", ucpi->c_cgx);
 142
 143         for (; beg < end; ++beg) {
 144                 bh = sb_getblk(sb, beg);
 145                 lock_buffer(bh);
 146                 memset(bh->b_data, 0, sb->s_blocksize);
 147                 set_buffer_uptodate(bh);
 148                 mark_buffer_dirty(bh);
 149                 unlock_buffer(bh);
 150                 if (sb->s_flags & MS_SYNCHRONOUS)
 151                         sync_dirty_buffer(bh);
 152                 brelse(bh);
 153         }
 154
 155         fs32_add(sb, &ucg->cg_u.cg_u2.cg_initediblk, uspi->s_inopb);
 156         ubh_mark_buffer_dirty(UCPI_UBH(ucpi));
 157         if (sb->s_flags & MS_SYNCHRONOUS)
 158                 ubh_sync_block(UCPI_UBH(ucpi));
 159
 160         UFSD("EXIT\n");
 161 }
 162
 163 /*
 164  * There are two policies for allocating an inode.  If the new inode is
 165  * a directory, then a forward search is made for a block group with both
 166  * free space and a low directory-to-inode ratio; if that fails, then of
 167  * the groups with above-average free space, that group with the fewest
 168  * directories already is chosen.
 169  *
 170  * For other inodes, search forward from the parent directory's block
 171  * group to find a free inode.
 172  */
 173 struct inode * ufs_new_inode(struct inode * dir, int mode)
 174 {
 175         struct super_block * sb;
 176         struct ufs_sb_info * sbi;
 177         struct ufs_sb_private_info * uspi;
 178         struct ufs_super_block_first * usb1;
 179         struct ufs_cg_private_info * ucpi;
 180         struct ufs_cylinder_group * ucg;
 181         struct inode * inode;
 182         unsigned cg, bit, i, j, start;
 183         struct ufs_inode_info *ufsi;
 184         int err = -ENOSPC;
 185
 186         UFSD("ENTER\n");
 187
 188         /* Cannot create files in a deleted directory */
 189         if (!dir || !dir->i_nlink)
 190                 return ERR_PTR(-EPERM);
 191         sb = dir->i_sb;
 192         inode = new_inode(sb);
 193         if (!inode)
 194                 return ERR_PTR(-ENOMEM);
 195         ufsi = UFS_I(inode);
 196         sbi = UFS_SB(sb);
 197         uspi = sbi->s_uspi;
 198         usb1 = ubh_get_usb_first(uspi);
 199
 200         lock_super (sb);
 201
 202         /*
 203          * Try to place the inode in its parent directory
 204          */
 205         i = ufs_inotocg(dir->i_ino);
 206         if (sbi->fs_cs(i).cs_nifree) {
 207                 cg = i;
 208                 goto cg_found;
 209         }
 210
 211         /*
 212          * Use a quadratic hash to find a group with a free inode
 213          */
 214         for ( j = 1; j < uspi->s_ncg; j <<= 1 ) {
 215                 i += j;
 216                 if (i >= uspi->s_ncg)
 217                         i -= uspi->s_ncg;
 218                 if (sbi->fs_cs(i).cs_nifree) {
 219                         cg = i;
 220                         goto cg_found;
 221                 }
 222         }
 223
 224         /*
 225          * That failed: try linear search for a free inode
 226          */
 227         i = ufs_inotocg(dir->i_ino) + 1;
 228         for (j = 2; j < uspi->s_ncg; j++) {
 229                 i++;
 230                 if (i >= uspi->s_ncg)
 231                         i = 0;
 232                 if (sbi->fs_cs(i).cs_nifree) {
 233                         cg = i;
 234                         goto cg_found;
 235                 }
 236         }
 237
 238         goto failed;
 239
 240 cg_found:
 241         ucpi = ufs_load_cylinder (sb, cg);
 242         if (!ucpi) {
 243                 err = -EIO;
 244                 goto failed;
 245         }
 246         ucg = ubh_get_ucg(UCPI_UBH(ucpi));
 247         if (!ufs_cg_chkmagic(sb, ucg))
 248                 ufs_panic (sb, "ufs_new_inode", "internal error, bad cg magic number");
 249
 250         start = ucpi->c_irotor;
 251         bit = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, uspi->s_ipg, start);
 252         if (!(bit < uspi->s_ipg)) {
 253                 bit = ubh_find_first_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, start);
 254                 if (!(bit < start)) {
 255                         ufs_error (sb, "ufs_new_inode",
 256                             "cylinder group %u corrupted - error in inode bitmap\n", cg);
 257                         err = -EIO;
 258                         goto failed;
 259                 }
 260         }
 261         UFSD("start = %u, bit = %u, ipg = %u\n", start, bit, uspi->s_ipg);
 262         if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
 263                 ubh_setbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
 264         else {
 265                 ufs_panic (sb, "ufs_new_inode", "internal error");
 266                 err = -EIO;
 267                 goto failed;
 268         }
 269
 270         if (uspi->fs_magic == UFS2_MAGIC) {
 271                 u32 initediblk = fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk);
 272
 273                 if (bit + uspi->s_inopb > initediblk &&
 274                     initediblk < fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_niblk))
 275                         ufs2_init_inodes_chunk(sb, ucpi, ucg);
 276         }
 277
 278         fs32_sub(sb, &ucg->cg_cs.cs_nifree, 1);
 279         uspi->cs_total.cs_nifree--;
 280         fs32_sub(sb, &sbi->fs_cs(cg).cs_nifree, 1);
 281
 282         if (S_ISDIR(mode)) {
 283                 fs32_add(sb, &ucg->cg_cs.cs_ndir, 1);
 284                 uspi->cs_total.cs_ndir++;
 285                 fs32_add(sb, &sbi->fs_cs(cg).cs_ndir, 1);
 286         }
 287         ubh_mark_buffer_dirty (USPI_UBH(uspi));
 288         ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
 289         if (sb->s_flags & MS_SYNCHRONOUS)
 290                 ubh_sync_block(UCPI_UBH(ucpi));
 291         sb->s_dirt = 1;
 292
 293         inode->i_ino = cg * uspi->s_ipg + bit;
 294         inode_init_owner(inode, dir, mode);
 295         inode->i_blocks = 0;
 296         inode->i_generation = 0;
 297         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 298         ufsi->i_flags = UFS_I(dir)->i_flags;
 299         ufsi->i_lastfrag = 0;
 300         ufsi->i_shadow = 0;
 301         ufsi->i_osync = 0;
 302         ufsi->i_oeftflag = 0;
 303         ufsi->i_dir_start_lookup = 0;
 304         memset(&ufsi->i_u1, 0, sizeof(ufsi->i_u1));
 305         insert_inode_hash(inode);
 306         mark_inode_dirty(inode);
 307
 308         if (uspi->fs_magic == UFS2_MAGIC) {
 309                 struct buffer_head *bh;
 310                 struct ufs2_inode *ufs2_inode;
 311
 312                 /*
 313                  * setup birth date, we do it here because of there is no sense
 314                  * to hold it in struct ufs_inode_info, and lose 64 bit
 315                  */
 316                 bh = sb_bread(sb, uspi->s_sbbase + ufs_inotofsba(inode->i_ino));
 317                 if (!bh) {
 318                         ufs_warning(sb, "ufs_read_inode",
 319                                     "unable to read inode %lu\n",
 320                                     inode->i_ino);
 321                         err = -EIO;
 322                         goto fail_remove_inode;
 323                 }
 324                 lock_buffer(bh);
 325                 ufs2_inode = (struct ufs2_inode *)bh->b_data;
 326                 ufs2_inode += ufs_inotofsbo(inode->i_ino);
 327                 ufs2_inode->ui_birthtime = cpu_to_fs64(sb, CURRENT_TIME.tv_sec);
 328                 ufs2_inode->ui_birthnsec = cpu_to_fs32(sb, CURRENT_TIME.tv_nsec);
 329                 mark_buffer_dirty(bh);
 330                 unlock_buffer(bh);
 331                 if (sb->s_flags & MS_SYNCHRONOUS)
 332                         sync_dirty_buffer(bh);
 333                 brelse(bh);
 334         }
 335
 336         unlock_super (sb);
 337
 338         UFSD("allocating inode %lu\n", inode->i_ino);
 339         UFSD("EXIT\n");
 340         return inode;
 341
 342 fail_remove_inode:
 343         unlock_super(sb);
 344         inode->i_nlink = 0;
 345         iput(inode);
 346         UFSD("EXIT (FAILED): err %d\n", err);
 347         return ERR_PTR(err);
 348 failed:
 349         unlock_super (sb);
 350         make_bad_inode(inode);
 351         iput (inode);
 352         UFSD("EXIT (FAILED): err %d\n", err);
 353         return ERR_PTR(err);
 354 }