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
  23 #include <linux/fs.h>
  24 #include <linux/ufs_fs.h>
  25 #include <linux/time.h>
  26 #include <linux/stat.h>
  27 #include <linux/string.h>
  28 #include <linux/quotaops.h>
  29 #include <linux/buffer_head.h>
  30 #include <linux/sched.h>
  31 #include <linux/bitops.h>
  32 #include <asm/byteorder.h>
  33
  34 #include "swab.h"
  35 #include "util.h"
  36
  37 /*
  38  * NOTE! When we get the inode, we're the only people
  39  * that have access to it, and as such there are no
  40  * race conditions we have to worry about. The inode
  41  * is not on the hash-lists, and it cannot be reached
  42  * through the filesystem because the directory entry
  43  * has been deleted earlier.
  44  *
  45  * HOWEVER: we must make sure that we get no aliases,
  46  * which means that we have to call "clear_inode()"
  47  * _before_ we mark the inode not in use in the inode
  48  * bitmaps. Otherwise a newly created file might use
  49  * the same inode number (not actually the same pointer
  50  * though), and then we'd have two inodes sharing the
  51  * same inode number and space on the harddisk.
  52  */
  53 void ufs_free_inode (struct inode * inode)
  54 {
  55         struct super_block * sb;
  56         struct ufs_sb_private_info * uspi;
  57         struct ufs_super_block_first * usb1;
  58         struct ufs_cg_private_info * ucpi;
  59         struct ufs_cylinder_group * ucg;
  60         int is_directory;
  61         unsigned ino, cg, bit;
  62
  63         UFSD("ENTER, ino %lu\n", inode->i_ino);
  64
  65         sb = inode->i_sb;
  66         uspi = UFS_SB(sb)->s_uspi;
  67         usb1 = ubh_get_usb_first(uspi);
  68
  69         ino = inode->i_ino;
  70
  71         lock_super (sb);
  72
  73         if (!((ino > 1) && (ino < (uspi->s_ncg * uspi->s_ipg )))) {
  74                 ufs_warning(sb, "ufs_free_inode", "reserved inode or nonexistent inode %u\n", ino);
  75                 unlock_super (sb);
  76                 return;
  77         }
  78
  79         cg = ufs_inotocg (ino);
  80         bit = ufs_inotocgoff (ino);
  81         ucpi = ufs_load_cylinder (sb, cg);
  82         if (!ucpi) {
  83                 unlock_super (sb);
  84                 return;
  85         }
  86         ucg = ubh_get_ucg(UCPI_UBH(ucpi));
  87         if (!ufs_cg_chkmagic(sb, ucg))
  88                 ufs_panic (sb, "ufs_free_fragments", "internal error, bad cg magic number");
  89
  90         ucg->cg_time = cpu_to_fs32(sb, get_seconds());
  91
  92         is_directory = S_ISDIR(inode->i_mode);
  93
  94         DQUOT_FREE_INODE(inode);
  95         DQUOT_DROP(inode);
  96
  97         clear_inode (inode);
  98
  99         if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
 100                 ufs_error(sb, "ufs_free_inode", "bit already cleared for inode %u", ino);
 101         else {
 102                 ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
 103                 if (ino < ucpi->c_irotor)
 104                         ucpi->c_irotor = ino;
 105                 fs32_add(sb, &ucg->cg_cs.cs_nifree, 1);
 106                 uspi->cs_total.cs_nifree++;
 107                 fs32_add(sb, &UFS_SB(sb)->fs_cs(cg).cs_nifree, 1);
 108
 109                 if (is_directory) {
 110                         fs32_sub(sb, &ucg->cg_cs.cs_ndir, 1);
 111                         uspi->cs_total.cs_ndir--;
 112                         fs32_sub(sb, &UFS_SB(sb)->fs_cs(cg).cs_ndir, 1);
 113                 }
 114         }
 115
 116         ubh_mark_buffer_dirty (USPI_UBH(uspi));
 117         ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
 118         if (sb->s_flags & MS_SYNCHRONOUS) {
 119                 ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
 120                 ubh_wait_on_buffer (UCPI_UBH(ucpi));
 121         }
 122
 123         sb->s_dirt = 1;
 124         unlock_super (sb);
 125         UFSD("EXIT\n");
 126 }
 127
 128 /*
 129  * There are two policies for allocating an inode.  If the new inode is
 130  * a directory, then a forward search is made for a block group with both
 131  * free space and a low directory-to-inode ratio; if that fails, then of
 132  * the groups with above-average free space, that group with the fewest
 133  * directories already is chosen.
 134  *
 135  * For other inodes, search forward from the parent directory's block
 136  * group to find a free inode.
 137  */
 138 struct inode * ufs_new_inode(struct inode * dir, int mode)
 139 {
 140         struct super_block * sb;
 141         struct ufs_sb_info * sbi;
 142         struct ufs_sb_private_info * uspi;
 143         struct ufs_super_block_first * usb1;
 144         struct ufs_cg_private_info * ucpi;
 145         struct ufs_cylinder_group * ucg;
 146         struct inode * inode;
 147         unsigned cg, bit, i, j, start;
 148         struct ufs_inode_info *ufsi;
 149
 150         UFSD("ENTER\n");
 151
 152         /* Cannot create files in a deleted directory */
 153         if (!dir || !dir->i_nlink)
 154                 return ERR_PTR(-EPERM);
 155         sb = dir->i_sb;
 156         inode = new_inode(sb);
 157         if (!inode)
 158                 return ERR_PTR(-ENOMEM);
 159         ufsi = UFS_I(inode);
 160         sbi = UFS_SB(sb);
 161         uspi = sbi->s_uspi;
 162         usb1 = ubh_get_usb_first(uspi);
 163
 164         lock_super (sb);
 165
 166         /*
 167          * Try to place the inode in its parent directory
 168          */
 169         i = ufs_inotocg(dir->i_ino);
 170         if (sbi->fs_cs(i).cs_nifree) {
 171                 cg = i;
 172                 goto cg_found;
 173         }
 174
 175         /*
 176          * Use a quadratic hash to find a group with a free inode
 177          */
 178         for ( j = 1; j < uspi->s_ncg; j <<= 1 ) {
 179                 i += j;
 180                 if (i >= uspi->s_ncg)
 181                         i -= uspi->s_ncg;
 182                 if (sbi->fs_cs(i).cs_nifree) {
 183                         cg = i;
 184                         goto cg_found;
 185                 }
 186         }
 187
 188         /*
 189          * That failed: try linear search for a free inode
 190          */
 191         i = ufs_inotocg(dir->i_ino) + 1;
 192         for (j = 2; j < uspi->s_ncg; j++) {
 193                 i++;
 194                 if (i >= uspi->s_ncg)
 195                         i = 0;
 196                 if (sbi->fs_cs(i).cs_nifree) {
 197                         cg = i;
 198                         goto cg_found;
 199                 }
 200         }
 201
 202         goto failed;
 203
 204 cg_found:
 205         ucpi = ufs_load_cylinder (sb, cg);
 206         if (!ucpi)
 207                 goto failed;
 208         ucg = ubh_get_ucg(UCPI_UBH(ucpi));
 209         if (!ufs_cg_chkmagic(sb, ucg))
 210                 ufs_panic (sb, "ufs_new_inode", "internal error, bad cg magic number");
 211
 212         start = ucpi->c_irotor;
 213         bit = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, uspi->s_ipg, start);
 214         if (!(bit < uspi->s_ipg)) {
 215                 bit = ubh_find_first_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, start);
 216                 if (!(bit < start)) {
 217                         ufs_error (sb, "ufs_new_inode",
 218                             "cylinder group %u corrupted - error in inode bitmap\n", cg);
 219                         goto failed;
 220                 }
 221         }
 222         UFSD("start = %u, bit = %u, ipg = %u\n", start, bit, uspi->s_ipg);
 223         if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
 224                 ubh_setbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
 225         else {
 226                 ufs_panic (sb, "ufs_new_inode", "internal error");
 227                 goto failed;
 228         }
 229
 230         fs32_sub(sb, &ucg->cg_cs.cs_nifree, 1);
 231         uspi->cs_total.cs_nifree--;
 232         fs32_sub(sb, &sbi->fs_cs(cg).cs_nifree, 1);
 233
 234         if (S_ISDIR(mode)) {
 235                 fs32_add(sb, &ucg->cg_cs.cs_ndir, 1);
 236                 uspi->cs_total.cs_ndir++;
 237                 fs32_add(sb, &sbi->fs_cs(cg).cs_ndir, 1);
 238         }
 239
 240         ubh_mark_buffer_dirty (USPI_UBH(uspi));
 241         ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
 242         if (sb->s_flags & MS_SYNCHRONOUS) {
 243                 ubh_ll_rw_block(SWRITE, UCPI_UBH(ucpi));
 244                 ubh_wait_on_buffer (UCPI_UBH(ucpi));
 245         }
 246         sb->s_dirt = 1;
 247
 248         inode->i_mode = mode;
 249         inode->i_uid = current->fsuid;
 250         if (dir->i_mode & S_ISGID) {
 251                 inode->i_gid = dir->i_gid;
 252                 if (S_ISDIR(mode))
 253                         inode->i_mode |= S_ISGID;
 254         } else
 255                 inode->i_gid = current->fsgid;
 256
 257         inode->i_ino = cg * uspi->s_ipg + bit;
 258         inode->i_blocks = 0;
 259         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 260         ufsi->i_flags = UFS_I(dir)->i_flags;
 261         ufsi->i_lastfrag = 0;
 262         ufsi->i_gen = 0;
 263         ufsi->i_shadow = 0;
 264         ufsi->i_osync = 0;
 265         ufsi->i_oeftflag = 0;
 266         ufsi->i_dir_start_lookup = 0;
 267         memset(&ufsi->i_u1, 0, sizeof(ufsi->i_u1));
 268
 269         insert_inode_hash(inode);
 270         mark_inode_dirty(inode);
 271
 272         unlock_super (sb);
 273
 274         if (DQUOT_ALLOC_INODE(inode)) {
 275                 DQUOT_DROP(inode);
 276                 inode->i_flags |= S_NOQUOTA;
 277                 inode->i_nlink = 0;
 278                 iput(inode);
 279                 return ERR_PTR(-EDQUOT);
 280         }
 281
 282         UFSD("allocating inode %lu\n", inode->i_ino);
 283         UFSD("EXIT\n");
 284         return inode;
 285
 286 failed:
 287         unlock_super (sb);
 288         make_bad_inode(inode);
 289         iput (inode);
 290         UFSD("EXIT (FAILED)\n");
 291         return ERR_PTR(-ENOSPC);
 292 }