minix/fs/mfs/mount.c

   1 #include "fs.h"
   2 #include "inode.h"
   3 #include "super.h"
   4 #include <minix/vfsif.h>
   5 #include <minix/bdev.h>
   6
   7 /*===========================================================================*
   8  *                              fs_mount                                     *
   9  *===========================================================================*/
  10 int fs_mount(dev_t dev, unsigned int flags, struct fsdriver_node *root_node,
  11         unsigned int *res_flags)
  12 {
  13 /* This function reads the superblock of the partition, gets the root inode
  14  * and sends back the details of them.
  15  */
  16   struct inode *root_ip;
  17   int r, readonly;
  18
  19   fs_dev = dev;
  20   readonly = (flags & REQ_RDONLY) ? 1 : 0;
  21
  22   /* Open the device the file system lives on. */
  23   if (bdev_open(fs_dev, readonly ? BDEV_R_BIT : (BDEV_R_BIT|BDEV_W_BIT) ) !=
  24                 OK) {
  25         return(EINVAL);
  26   }
  27
  28   /* Fill in the super block. */
  29   superblock.s_dev = fs_dev;    /* read_super() needs to know which dev */
  30   r = read_super(&superblock);
  31
  32   /* Is it recognized as a Minix filesystem? */
  33   if (r != OK) {
  34         superblock.s_dev = NO_DEV;
  35         bdev_close(fs_dev);
  36         return(r);
  37   }
  38
  39   /* clean check: if rw and not clean, switch to readonly */
  40   if(!(superblock.s_flags & MFSFLAG_CLEAN) && !readonly) {
  41         if(bdev_close(fs_dev) != OK)
  42                 panic("couldn't bdev_close after found unclean FS");
  43         readonly = 1;
  44
  45         if (bdev_open(fs_dev, BDEV_R_BIT) != OK) {
  46                 panic("couldn't bdev_open after found unclean FS");
  47                 return(EINVAL);
  48         }
  49         printf("MFS: WARNING: FS 0x%llx unclean, mounting readonly\n", fs_dev);
  50   }
  51
  52   lmfs_set_blocksize(superblock.s_block_size);
  53
  54   /* Compute the current number of used zones, and report it to libminixfs.
  55    * Note that libminixfs really wants numbers of *blocks*, but this MFS
  56    * implementation dropped support for differing zone/block sizes a while ago.
  57    */
  58   used_zones = superblock.s_zones - count_free_bits(&superblock, ZMAP);
  59
  60   lmfs_set_blockusage(superblock.s_zones, used_zones);
  61
  62   /* Get the root inode of the mounted file system. */
  63   if( (root_ip = get_inode(fs_dev, ROOT_INODE)) == NULL)  {
  64         printf("MFS: couldn't get root inode\n");
  65         superblock.s_dev = NO_DEV;
  66         bdev_close(fs_dev);
  67         return(EINVAL);
  68   }
  69
  70   if(root_ip->i_mode == 0) {
  71         printf("%s:%d zero mode for root inode?\n", __FILE__, __LINE__);
  72         put_inode(root_ip);
  73         superblock.s_dev = NO_DEV;
  74         bdev_close(fs_dev);
  75         return(EINVAL);
  76   }
  77
  78   superblock.s_rd_only = readonly;
  79
  80   /* Root inode properties */
  81   root_node->fn_ino_nr = root_ip->i_num;
  82   root_node->fn_mode = root_ip->i_mode;
  83   root_node->fn_size = root_ip->i_size;
  84   root_node->fn_uid = root_ip->i_uid;
  85   root_node->fn_gid = root_ip->i_gid;
  86   root_node->fn_dev = NO_DEV;
  87
  88   *res_flags = RES_NOFLAGS;
  89
  90   /* Mark it dirty */
  91   if(!superblock.s_rd_only) {
  92           superblock.s_flags &= ~MFSFLAG_CLEAN;
  93           if(write_super(&superblock) != OK)
  94                 panic("mounting: couldn't write dirty superblock");
  95   }
  96
  97   return(r);
  98 }
  99
 100
 101 /*===========================================================================*
 102  *                              fs_mountpt                                   *
 103  *===========================================================================*/
 104 int fs_mountpt(ino_t ino_nr)
 105 {
 106 /* This function looks up the mount point, it checks the condition whether
 107  * the partition can be mounted on the inode or not.
 108  */
 109   register struct inode *rip;
 110   int r = OK;
 111   mode_t bits;
 112
 113   /* Temporarily open the file. */
 114   if( (rip = get_inode(fs_dev, ino_nr)) == NULL)
 115           return(EINVAL);
 116
 117   if(rip->i_mountpoint) r = EBUSY;
 118
 119   /* It may not be special. */
 120   bits = rip->i_mode & I_TYPE;
 121   if (bits == I_BLOCK_SPECIAL || bits == I_CHAR_SPECIAL) r = ENOTDIR;
 122
 123   put_inode(rip);
 124
 125   if(r == OK) rip->i_mountpoint = TRUE;
 126
 127   return(r);
 128 }
 129
 130
 131 /*===========================================================================*
 132  *                              fs_unmount                                   *
 133  *===========================================================================*/
 134 void fs_unmount(void)
 135 {
 136 /* Unmount a file system. */
 137   int count;
 138   struct inode *rip, *root_ip;
 139
 140   /* See if the mounted device is busy.  Only 1 inode using it should be
 141    * open --the root inode-- and that inode only 1 time.  This is an integrity
 142    * check only: VFS expects the unmount to succeed either way.
 143    */
 144   count = 0;
 145   for (rip = &inode[0]; rip < &inode[NR_INODES]; rip++)
 146           if (rip->i_count > 0 && rip->i_dev == fs_dev) count += rip->i_count;
 147   if (count != 1)
 148         printf("MFS: file system has %d in-use inodes!\n", count);
 149
 150   if ((root_ip = find_inode(fs_dev, ROOT_INODE)) == NULL)
 151         panic("MFS: couldn't find root inode\n");
 152
 153   put_inode(root_ip);
 154
 155   /* force any cached blocks out of memory */
 156   fs_sync();
 157
 158   /* Mark it clean if we're allowed to write _and_ it was clean originally. */
 159   if (!superblock.s_rd_only) {
 160         superblock.s_flags |= MFSFLAG_CLEAN;
 161         write_super(&superblock);
 162   }
 163
 164   /* Close the device the file system lives on. */
 165   bdev_close(fs_dev);
 166
 167   /* Throw out blocks out of the VM cache, to prevent corruption later. */
 168   lmfs_invalidate(fs_dev);
 169
 170   /* Finish off the unmount. */
 171   superblock.s_dev = NO_DEV;
 172 }
 173