fs/sysv/ialloc.c

   1 /*
   2  *  linux/fs/sysv/ialloc.c
   3  *
   4  *  minix/bitmap.c
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  *
   7  *  ext/freelists.c
   8  *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
   9  *
  10  *  xenix/alloc.c
  11  *  Copyright (C) 1992  Doug Evans
  12  *
  13  *  coh/alloc.c
  14  *  Copyright (C) 1993  Pascal Haible, Bruno Haible
  15  *
  16  *  sysv/ialloc.c
  17  *  Copyright (C) 1993  Bruno Haible
  18  *
  19  *  This file contains code for allocating/freeing inodes.
  20  */
  21
  22 #include <linux/sched.h>
  23 #include <linux/kernel.h>
  24 #include <linux/fs.h>
  25 #include <linux/sysv_fs.h>
  26 #include <linux/stddef.h>
  27 #include <linux/stat.h>
  28 #include <linux/string.h>
  29 #include <linux/locks.h>
  30
  31 /* We don't trust the value of
  32    sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
  33    but we nevertheless keep it up to date. */
  34
  35 /* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
  36
  37 /* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
  38 static inline sysv_ino_t * sv_sb_fic_inode (struct super_block * sb, unsigned int i)
  39 {
  40         if (sb->sv_bh1 == sb->sv_bh2)
  41                 return &sb->sv_sb_fic_inodes[i];
  42         else {
  43                 /* 512 byte Xenix FS */
  44                 unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
  45                 if (offset < 512)
  46                         return (sysv_ino_t*)(sb->sv_sbd1 + offset);
  47                 else
  48                         return (sysv_ino_t*)(sb->sv_sbd2 + offset);
  49         }
  50 }
  51
  52 void sysv_free_inode(struct inode * inode)
  53 {
  54         struct super_block * sb;
  55         unsigned int ino;
  56         struct buffer_head * bh;
  57         struct sysv_inode * raw_inode;
  58
  59         if (!inode)
  60                 return;
  61         if (!inode->i_dev) {
  62                 printk("sysv_free_inode: inode has no device\n");
  63                 return;
  64         }
  65         if (inode->i_count != 1) {
  66                 printk("sysv_free_inode: inode has count=%d\n", inode->i_count);
  67                 return;
  68         }
  69         if (inode->i_nlink) {
  70                 printk("sysv_free_inode: inode has nlink=%d\n", inode->i_nlink);
  71                 return;
  72         }
  73         if (!(sb = inode->i_sb)) {
  74                 printk("sysv_free_inode: inode on nonexistent device\n");
  75                 return;
  76         }
  77         ino = inode->i_ino;
  78         if (ino <= SYSV_ROOT_INO || ino > sb->sv_ninodes) {
  79                 printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
  80                 return;
  81         }
  82         if (!(bh = sv_bread(sb, inode->i_dev, sb->sv_firstinodezone + ((ino-1) >> sb->sv_inodes_per_block_bits)))) {
  83                 printk("sysv_free_inode: unable to read inode block on device "
  84                        "%s\n", kdevname(inode->i_dev));
  85                 clear_inode(inode);
  86                 return;
  87         }
  88         raw_inode = (struct sysv_inode *) bh->b_data + ((ino-1) & sb->sv_inodes_per_block_1);
  89         clear_inode(inode);
  90         lock_super(sb);
  91         if (*sb->sv_sb_fic_count < sb->sv_fic_size)
  92                 *sv_sb_fic_inode(sb,(*sb->sv_sb_fic_count)++) = ino;
  93         (*sb->sv_sb_total_free_inodes)++;
  94         mark_buffer_dirty(sb->sv_bh1, 1); /* super-block has been modified */
  95         if (sb->sv_bh1 != sb->sv_bh2) mark_buffer_dirty(sb->sv_bh2, 1);
  96         sb->s_dirt = 1; /* and needs time stamp */
  97         memset(raw_inode, 0, sizeof(struct sysv_inode));
  98         mark_buffer_dirty(bh, 1);
  99         unlock_super(sb);
 100         brelse(bh);
 101 }
 102
 103 struct inode * sysv_new_inode(const struct inode * dir)
 104 {
 105         struct inode * inode;
 106         struct super_block * sb;
 107         struct buffer_head * bh;
 108         struct sysv_inode * raw_inode;
 109         int i,j,ino,block;
 110
 111         if (!dir || !(inode = get_empty_inode()))
 112                 return NULL;
 113         sb = dir->i_sb;
 114         inode->i_sb = sb;
 115         inode->i_flags = 0;
 116         lock_super(sb);         /* protect against task switches */
 117         if ((*sb->sv_sb_fic_count == 0)
 118             || (*sv_sb_fic_inode(sb,(*sb->sv_sb_fic_count)-1) == 0) /* Applies only to SystemV2 FS */
 119            ) {
 120                 /* Rebuild cache of free inodes: */
 121                 /* i : index into cache slot being filled            */
 122                 /* ino : inode we are trying                         */
 123                 /* block : firstinodezone + (ino-1)/inodes_per_block */
 124                 /* j : (ino-1)%inodes_per_block                      */
 125                 /* bh : buffer for block                             */
 126                 /* raw_inode : pointer to inode ino in the block     */
 127                 for (i = 0, ino = SYSV_ROOT_INO+1, block = sb->sv_firstinodezone, j = SYSV_ROOT_INO ; i < sb->sv_fic_size && block < sb->sv_firstdatazone ; block++, j = 0) {
 128                         if (!(bh = sv_bread(sb, sb->s_dev, block))) {
 129                                 printk("sysv_new_inode: unable to read inode table\n");
 130                                 break;  /* go with what we've got */
 131                                 /* FIXME: Perhaps try the next block? */
 132                         }
 133                         raw_inode = (struct sysv_inode *) bh->b_data + j;
 134                         for (; j < sb->sv_inodes_per_block && i < sb->sv_fic_size; ino++, j++, raw_inode++) {
 135                                 if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
 136                                         *sv_sb_fic_inode(sb,i++) = ino;
 137                         }
 138                         brelse(bh);
 139                 }
 140                 if (i == 0) {
 141                         iput(inode);
 142                         unlock_super(sb);
 143                         return NULL;    /* no inodes available */
 144                 }
 145                 *sb->sv_sb_fic_count = i;
 146         }
 147         /* Now *sb->sv_sb_fic_count > 0. */
 148         ino = *sv_sb_fic_inode(sb,--(*sb->sv_sb_fic_count));
 149         mark_buffer_dirty(sb->sv_bh1, 1); /* super-block has been modified */
 150         if (sb->sv_bh1 != sb->sv_bh2) mark_buffer_dirty(sb->sv_bh2, 1);
 151         sb->s_dirt = 1; /* and needs time stamp */
 152         inode->i_count = 1;
 153         inode->i_nlink = 1;
 154         inode->i_dev = sb->s_dev;
 155         inode->i_uid = current->fsuid;
 156         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 157         inode->i_ino = ino;
 158         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 159         inode->i_op = NULL;
 160         inode->i_blocks = inode->i_blksize = 0;
 161         insert_inode_hash(inode);
 162         mark_inode_dirty(inode);
 163         /* Change directory entry: */
 164         inode->i_mode = 0;              /* for sysv_write_inode() */
 165         inode->i_size = 0;              /* ditto */
 166         sysv_write_inode(inode);        /* ensure inode not allocated again */
 167                                         /* FIXME: caller may call this too. */
 168         mark_inode_dirty(inode);        /* cleared by sysv_write_inode() */
 169         /* That's it. */
 170         (*sb->sv_sb_total_free_inodes)--;
 171         mark_buffer_dirty(sb->sv_bh2, 1); /* super-block has been modified again */
 172         sb->s_dirt = 1; /* and needs time stamp again */
 173         unlock_super(sb);
 174         return inode;
 175 }
 176
 177 unsigned long sysv_count_free_inodes(struct super_block * sb)
 178 {
 179 #if 1 /* test */
 180         struct buffer_head * bh;
 181         struct sysv_inode * raw_inode;
 182         int j,block,count;
 183
 184         /* this causes a lot of disk traffic ... */
 185         count = 0;
 186         lock_super(sb);
 187         /* i : index into cache slot being filled            */
 188         /* ino : inode we are trying                         */
 189         /* block : firstinodezone + (ino-1)/inodes_per_block */
 190         /* j : (ino-1)%inodes_per_block                      */
 191         /* bh : buffer for block                             */
 192         /* raw_inode : pointer to inode ino in the block     */
 193         for (block = sb->sv_firstinodezone, j = SYSV_ROOT_INO ; block < sb->sv_firstdatazone ; block++, j = 0) {
 194                 if (!(bh = sv_bread(sb, sb->s_dev, block))) {
 195                         printk("sysv_count_free_inodes: unable to read inode table\n");
 196                         break;  /* go with what we've got */
 197                         /* FIXME: Perhaps try the next block? */
 198                 }
 199                 raw_inode = (struct sysv_inode *) bh->b_data + j;
 200                 for (; j < sb->sv_inodes_per_block ; j++, raw_inode++)
 201                         if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
 202                                 count++;
 203                 brelse(bh);
 204         }
 205         if (count != *sb->sv_sb_total_free_inodes) {
 206                 printk("sysv_count_free_inodes: free inode count was %d, correcting to %d\n",(short)(*sb->sv_sb_total_free_inodes),count);
 207                 if (!(sb->s_flags & MS_RDONLY)) {
 208                         *sb->sv_sb_total_free_inodes = count;
 209                         mark_buffer_dirty(sb->sv_bh2, 1); /* super-block has been modified */
 210                         sb->s_dirt = 1; /* and needs time stamp */
 211                 }
 212         }
 213         unlock_super(sb);
 214         return count;
 215 #else
 216         return *sb->sv_sb_total_free_inodes;
 217 #endif
 218 }
 219