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/sched.h>
  26 #include <linux/stat.h>
  27 #include <linux/string.h>
  28 #include <linux/locks.h>
  29 #include <linux/quotaops.h>
  30 #include <asm/bitops.h>
  31 #include <asm/byteorder.h>
  32
  33 #include "swab.h"
  34 #include "util.h"
  35
  36 #undef UFS_IALLOC_DEBUG
  37
  38 #ifdef UFS_IALLOC_DEBUG
  39 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
  40 #else
  41 #define UFSD(x)
  42 #endif
  43
  44 /*
  45  * NOTE! When we get the inode, we're the only people
  46  * that have access to it, and as such there are no
  47  * race conditions we have to worry about. The inode
  48  * is not on the hash-lists, and it cannot be reached
  49  * through the filesystem because the directory entry
  50  * has been deleted earlier.
  51  *
  52  * HOWEVER: we must make sure that we get no aliases,
  53  * which means that we have to call "clear_inode()"
  54  * _before_ we mark the inode not in use in the inode
  55  * bitmaps. Otherwise a newly created file might use
  56  * the same inode number (not actually the same pointer
  57  * though), and then we'd have two inodes sharing the
  58  * same inode number and space on the harddisk.
  59  */
  60 void ufs_free_inode (struct inode * inode)
  61 {
  62         struct super_block * sb;
  63         struct ufs_sb_private_info * uspi;
  64         struct ufs_super_block_first * usb1;
  65         struct ufs_cg_private_info * ucpi;
  66         struct ufs_cylinder_group * ucg;
  67         int is_directory;
  68         unsigned ino, cg, bit;
  69         unsigned swab;
  70
  71         UFSD(("ENTER, ino %lu\n", inode->i_ino))
  72
  73         if (!inode)
  74                 return;
  75         sb = inode->i_sb;
  76         swab = sb->u.ufs_sb.s_swab;
  77         uspi = sb->u.ufs_sb.s_uspi;
  78         usb1 = ubh_get_usb_first(USPI_UBH);
  79
  80         if (inode->i_count > 1) {
  81                 ufs_warning(sb, "ufs_free_inode", "inode has count=%d\n", inode->i_count);
  82                 return;
  83         }
  84         if (inode->i_nlink) {
  85                 ufs_warning(sb, "ufs_free_inode", "inode has nlink=%d\n", inode->i_nlink);
  86                 return;
  87         }
  88
  89         ino = inode->i_ino;
  90
  91         lock_super (sb);
  92
  93         if (!((ino > 1) && (ino < (uspi->s_ncg * uspi->s_ipg )))) {
  94                 ufs_warning(sb, "ufs_free_inode", "reserved inode or nonexistent inode %u\n", ino);
  95                 unlock_super (sb);
  96                 return;
  97         }
  98
  99         cg = ufs_inotocg (ino);
 100         bit = ufs_inotocgoff (ino);
 101         ucpi = ufs_load_cylinder (sb, cg);
 102         if (!ucpi) {
 103                 unlock_super (sb);
 104                 return;
 105         }
 106         ucg = ubh_get_ucg(UCPI_UBH);
 107         if (!ufs_cg_chkmagic(ucg))
 108                 ufs_panic (sb, "ufs_free_fragments", "internal error, bad cg magic number");
 109
 110         ucg->cg_time = SWAB32(CURRENT_TIME);
 111
 112         is_directory = S_ISDIR(inode->i_mode);
 113
 114         DQUOT_FREE_INODE(sb, inode);
 115
 116         clear_inode (inode);
 117
 118         if (ubh_isclr (UCPI_UBH, ucpi->c_iusedoff, bit))
 119                 ufs_error(sb, "ufs_free_inode", "bit already cleared for inode %u", ino);
 120         else {
 121                 ubh_clrbit (UCPI_UBH, ucpi->c_iusedoff, bit);
 122                 if (ino < ucpi->c_irotor)
 123                         ucpi->c_irotor = ino;
 124                 INC_SWAB32(ucg->cg_cs.cs_nifree);
 125                 INC_SWAB32(usb1->fs_cstotal.cs_nifree);
 126                 INC_SWAB32(sb->fs_cs(cg).cs_nifree);
 127
 128                 if (is_directory) {
 129                         DEC_SWAB32(ucg->cg_cs.cs_ndir);
 130                         DEC_SWAB32(usb1->fs_cstotal.cs_ndir);
 131                         DEC_SWAB32(sb->fs_cs(cg).cs_ndir);
 132                 }
 133         }
 134         ubh_mark_buffer_dirty (USPI_UBH, 1);
 135         ubh_mark_buffer_dirty (UCPI_UBH, 1);
 136         if (sb->s_flags & MS_SYNCHRONOUS) {
 137                 ubh_ll_rw_block (WRITE, 1, (struct ufs_buffer_head **) &ucpi);
 138                 ubh_wait_on_buffer (UCPI_UBH);
 139         }
 140
 141         sb->s_dirt = 1;
 142         unlock_super (sb);
 143         UFSD(("EXIT\n"))
 144 }
 145
 146 /*
 147  * There are two policies for allocating an inode.  If the new inode is
 148  * a directory, then a forward search is made for a block group with both
 149  * free space and a low directory-to-inode ratio; if that fails, then of
 150  * the groups with above-average free space, that group with the fewest
 151  * directories already is chosen.
 152  *
 153  * For other inodes, search forward from the parent directory's block
 154  * group to find a free inode.
 155  */
 156 struct inode * ufs_new_inode (const struct inode * dir, int mode, int * err )
 157 {
 158         struct super_block * sb;
 159         struct ufs_sb_private_info * uspi;
 160         struct ufs_super_block_first * usb1;
 161         struct ufs_cg_private_info * ucpi;
 162         struct ufs_cylinder_group * ucg;
 163         struct inode * inode;
 164         unsigned cg, bit, i, j, start;
 165         unsigned swab;
 166
 167         UFSD(("ENTER\n"))
 168
 169         /* Cannot create files in a deleted directory */
 170         if (!dir || !dir->i_nlink) {
 171                 *err = -EPERM;
 172                 return NULL;
 173         }
 174         inode = get_empty_inode ();
 175         if (!inode) {
 176                 *err = -ENOMEM;
 177                 return NULL;
 178         }
 179         sb = dir->i_sb;
 180         swab = sb->u.ufs_sb.s_swab;
 181         uspi = sb->u.ufs_sb.s_uspi;
 182         usb1 = ubh_get_usb_first(USPI_UBH);
 183
 184         inode->i_sb = sb;
 185         inode->i_flags = 0;
 186
 187         lock_super (sb);
 188
 189         *err = -ENOSPC;
 190
 191         /*
 192          * Try to place the inode in its parent directory
 193          */
 194         i = ufs_inotocg(dir->i_ino);
 195         if (SWAB32(sb->fs_cs(i).cs_nifree)) {
 196                 cg = i;
 197                 goto cg_found;
 198         }
 199
 200         /*
 201          * Use a quadratic hash to find a group with a free inode
 202          */
 203         for ( j = 1; j < uspi->s_ncg; j <<= 1 ) {
 204                 i += j;
 205                 if (i >= uspi->s_ncg)
 206                         i -= uspi->s_ncg;
 207                 if (SWAB32(sb->fs_cs(i).cs_nifree)) {
 208                         cg = i;
 209                         goto cg_found;
 210                 }
 211         }
 212
 213         /*
 214          * That failed: try linear search for a free inode
 215          */
 216         i = ufs_inotocg(dir->i_ino) + 1;
 217         for (j = 2; j < uspi->s_ncg; j++) {
 218                 i++;
 219                 if (i >= uspi->s_ncg)
 220                         i = 0;
 221                 if (SWAB32(sb->fs_cs(i).cs_nifree)) {
 222                         cg = i;
 223                         goto cg_found;
 224                 }
 225         }
 226
 227         goto failed;
 228
 229 cg_found:
 230         ucpi = ufs_load_cylinder (sb, cg);
 231         if (!ucpi)
 232                 goto failed;
 233         ucg = ubh_get_ucg(UCPI_UBH);
 234         if (!ufs_cg_chkmagic(ucg))
 235                 ufs_panic (sb, "ufs_new_inode", "internal error, bad cg magic number");
 236
 237         start = ucpi->c_irotor;
 238         bit = ubh_find_next_zero_bit (UCPI_UBH, ucpi->c_iusedoff, uspi->s_ipg, start);
 239         if (!(bit < uspi->s_ipg)) {
 240                 bit = ubh_find_first_zero_bit (UCPI_UBH, ucpi->c_iusedoff, start);
 241                 if (!(bit < start)) {
 242                         ufs_error (sb, "ufs_new_inode",
 243                             "cylinder group %u corrupted - error in inode bitmap\n", cg);
 244                         goto failed;
 245                 }
 246         }
 247         UFSD(("start = %u, bit = %u, ipg = %u\n", start, bit, uspi->s_ipg))
 248         if (ubh_isclr (UCPI_UBH, ucpi->c_iusedoff, bit))
 249                 ubh_setbit (UCPI_UBH, ucpi->c_iusedoff, bit);
 250         else {
 251                 ufs_panic (sb, "ufs_new_inode", "internal error");
 252                 goto failed;
 253         }
 254
 255         DEC_SWAB32(ucg->cg_cs.cs_nifree);
 256         DEC_SWAB32(usb1->fs_cstotal.cs_nifree);
 257         DEC_SWAB32(sb->fs_cs(cg).cs_nifree);
 258
 259         if (S_ISDIR(mode)) {
 260                 INC_SWAB32(ucg->cg_cs.cs_ndir);
 261                 INC_SWAB32(usb1->fs_cstotal.cs_ndir);
 262                 INC_SWAB32(sb->fs_cs(cg).cs_ndir);
 263         }
 264
 265         ubh_mark_buffer_dirty (USPI_UBH, 1);
 266         ubh_mark_buffer_dirty (UCPI_UBH, 1);
 267         if (sb->s_flags & MS_SYNCHRONOUS) {
 268                 ubh_ll_rw_block (WRITE, 1, (struct ufs_buffer_head **) &ucpi);
 269                 ubh_wait_on_buffer (UCPI_UBH);
 270         }
 271         sb->s_dirt = 1;
 272
 273         inode->i_mode = mode;
 274         inode->i_sb = sb;
 275         inode->i_nlink = 1;
 276         inode->i_dev = sb->s_dev;
 277         inode->i_uid = current->fsuid;
 278         if (test_opt (sb, GRPID))
 279                 inode->i_gid = dir->i_gid;
 280         else if (dir->i_mode & S_ISGID) {
 281                 inode->i_gid = dir->i_gid;
 282                 if (S_ISDIR(mode))
 283                         mode |= S_ISGID;
 284         } else
 285                 inode->i_gid = current->fsgid;
 286
 287         inode->i_ino = cg * uspi->s_ipg + bit;
 288         inode->i_blksize = PAGE_SIZE;   /* This is the optimal IO size (for stat), not the fs block size */
 289         inode->i_blocks = 0;
 290         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 291         inode->u.ufs_i.i_flags = dir->u.ufs_i.i_flags;
 292         inode->u.ufs_i.i_uid = inode->i_uid;
 293         inode->u.ufs_i.i_gid = inode->i_gid;
 294         inode->u.ufs_i.i_lastfrag = 0;
 295         inode->i_op = NULL;
 296
 297         insert_inode_hash(inode);
 298         mark_inode_dirty(inode);
 299
 300         unlock_super (sb);
 301
 302         if(DQUOT_ALLOC_INODE(sb, inode)) {
 303                 sb->dq_op->drop(inode);
 304                 inode->i_nlink = 0;
 305                 iput(inode);
 306                 *err = -EDQUOT;
 307                 return NULL;
 308         }
 309
 310         UFSD(("allocating inode %lu\n", inode->i_ino))
 311         *err = 0;
 312         UFSD(("EXIT\n"))
 313         return inode;
 314
 315 failed:
 316         unlock_super (sb);
 317         iput (inode);
 318         UFSD(("EXIT (FAILED)\n"))
 319         return NULL;
 320 }