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         sb = inode->i_sb;
  60         ino = inode->i_ino;
  61         if (ino <= SYSV_ROOT_INO || ino > sb->sv_ninodes) {
  62                 printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
  63                 return;
  64         }
  65         if (!(bh = sv_bread(sb, inode->i_dev, sb->sv_firstinodezone + ((ino-1) >> sb->sv_inodes_per_block_bits)))) {
  66                 printk("sysv_free_inode: unable to read inode block on device "
  67                        "%s\n", kdevname(inode->i_dev));
  68                 clear_inode(inode);
  69                 return;
  70         }
  71         raw_inode = (struct sysv_inode *) bh->b_data + ((ino-1) & sb->sv_inodes_per_block_1);
  72         clear_inode(inode);
  73         lock_super(sb);
  74         if (*sb->sv_sb_fic_count < sb->sv_fic_size)
  75                 *sv_sb_fic_inode(sb,(*sb->sv_sb_fic_count)++) = ino;
  76         (*sb->sv_sb_total_free_inodes)++;
  77         mark_buffer_dirty(sb->sv_bh1, 1); /* super-block has been modified */
  78         if (sb->sv_bh1 != sb->sv_bh2) mark_buffer_dirty(sb->sv_bh2, 1);
  79         sb->s_dirt = 1; /* and needs time stamp */
  80         memset(raw_inode, 0, sizeof(struct sysv_inode));
  81         mark_buffer_dirty(bh, 1);
  82         unlock_super(sb);
  83         brelse(bh);
  84 }
  85
  86 struct inode * sysv_new_inode(const struct inode * dir)
  87 {
  88         struct inode * inode;
  89         struct super_block * sb;
  90         struct buffer_head * bh;
  91         struct sysv_inode * raw_inode;
  92         int i,j,ino,block;
  93
  94         if (!dir || !(inode = get_empty_inode()))
  95                 return NULL;
  96         sb = dir->i_sb;
  97         inode->i_sb = sb;
  98         lock_super(sb);         /* protect against task switches */
  99         if ((*sb->sv_sb_fic_count == 0)
 100             || (*sv_sb_fic_inode(sb,(*sb->sv_sb_fic_count)-1) == 0) /* Applies only to SystemV2 FS */
 101            ) {
 102                 /* Rebuild cache of free inodes: */
 103                 /* i : index into cache slot being filled            */
 104                 /* ino : inode we are trying                         */
 105                 /* block : firstinodezone + (ino-1)/inodes_per_block */
 106                 /* j : (ino-1)%inodes_per_block                      */
 107                 /* bh : buffer for block                             */
 108                 /* raw_inode : pointer to inode ino in the block     */
 109                 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) {
 110                         if (!(bh = sv_bread(sb, sb->s_dev, block))) {
 111                                 printk("sysv_new_inode: unable to read inode table\n");
 112                                 break;  /* go with what we've got */
 113                                 /* FIXME: Perhaps try the next block? */
 114                         }
 115                         raw_inode = (struct sysv_inode *) bh->b_data + j;
 116                         for (; j < sb->sv_inodes_per_block && i < sb->sv_fic_size; ino++, j++, raw_inode++) {
 117                                 if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
 118                                         *sv_sb_fic_inode(sb,i++) = ino;
 119                         }
 120                         brelse(bh);
 121                 }
 122                 if (i == 0) {
 123                         iput(inode);
 124                         unlock_super(sb);
 125                         return NULL;    /* no inodes available */
 126                 }
 127                 *sb->sv_sb_fic_count = i;
 128         }
 129         /* Now *sb->sv_sb_fic_count > 0. */
 130         ino = *sv_sb_fic_inode(sb,--(*sb->sv_sb_fic_count));
 131         mark_buffer_dirty(sb->sv_bh1, 1); /* super-block has been modified */
 132         if (sb->sv_bh1 != sb->sv_bh2) mark_buffer_dirty(sb->sv_bh2, 1);
 133         sb->s_dirt = 1; /* and needs time stamp */
 134         inode->i_dev = sb->s_dev;
 135         inode->i_uid = current->fsuid;
 136         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 137         inode->i_ino = ino;
 138         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 139         inode->i_blocks = inode->i_blksize = 0;
 140         insert_inode_hash(inode);
 141         mark_inode_dirty(inode);
 142         /* Change directory entry: */
 143         inode->i_mode = 0;              /* for sysv_write_inode() */
 144         inode->i_size = 0;              /* ditto */
 145         sysv_write_inode(inode);        /* ensure inode not allocated again */
 146                                         /* FIXME: caller may call this too. */
 147         mark_inode_dirty(inode);        /* cleared by sysv_write_inode() */
 148         /* That's it. */
 149         (*sb->sv_sb_total_free_inodes)--;
 150         mark_buffer_dirty(sb->sv_bh2, 1); /* super-block has been modified again */
 151         sb->s_dirt = 1; /* and needs time stamp again */
 152         unlock_super(sb);
 153         return inode;
 154 }
 155
 156 unsigned long sysv_count_free_inodes(struct super_block * sb)
 157 {
 158 #if 1 /* test */
 159         struct buffer_head * bh;
 160         struct sysv_inode * raw_inode;
 161         int j,block,count;
 162
 163         /* this causes a lot of disk traffic ... */
 164         count = 0;
 165         lock_super(sb);
 166         /* i : index into cache slot being filled            */
 167         /* ino : inode we are trying                         */
 168         /* block : firstinodezone + (ino-1)/inodes_per_block */
 169         /* j : (ino-1)%inodes_per_block                      */
 170         /* bh : buffer for block                             */
 171         /* raw_inode : pointer to inode ino in the block     */
 172         for (block = sb->sv_firstinodezone, j = SYSV_ROOT_INO ; block < sb->sv_firstdatazone ; block++, j = 0) {
 173                 if (!(bh = sv_bread(sb, sb->s_dev, block))) {
 174                         printk("sysv_count_free_inodes: unable to read inode table\n");
 175                         break;  /* go with what we've got */
 176                         /* FIXME: Perhaps try the next block? */
 177                 }
 178                 raw_inode = (struct sysv_inode *) bh->b_data + j;
 179                 for (; j < sb->sv_inodes_per_block ; j++, raw_inode++)
 180                         if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
 181                                 count++;
 182                 brelse(bh);
 183         }
 184         if (count != *sb->sv_sb_total_free_inodes) {
 185                 printk("sysv_count_free_inodes: free inode count was %d, correcting to %d\n",(short)(*sb->sv_sb_total_free_inodes),count);
 186                 if (!(sb->s_flags & MS_RDONLY)) {
 187                         *sb->sv_sb_total_free_inodes = count;
 188                         mark_buffer_dirty(sb->sv_bh2, 1); /* super-block has been modified */
 189                         sb->s_dirt = 1; /* and needs time stamp */
 190                 }
 191         }
 192         unlock_super(sb);
 193         return count;
 194 #else
 195         return *sb->sv_sb_total_free_inodes;
 196 #endif
 197 }
 198