fs/reiserfs/ioctl.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4
   5 #include <linux/fs.h>
   6 #include <linux/reiserfs_fs.h>
   7 #include <linux/time.h>
   8 #include <asm/uaccess.h>
   9 #include <linux/pagemap.h>
  10 #include <linux/smp_lock.h>
  11
  12 static int reiserfs_unpack(struct inode *inode, struct file *filp);
  13
  14 /*
  15 ** reiserfs_ioctl - handler for ioctl for inode
  16 ** supported commands:
  17 **  1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
  18 **                           and prevent packing file (argument arg has to be non-zero)
  19 **  2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
  20 **  3) That's all for a while ...
  21 */
  22 int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
  23                    unsigned long arg)
  24 {
  25         unsigned int flags;
  26
  27         switch (cmd) {
  28         case REISERFS_IOC_UNPACK:
  29                 if (S_ISREG(inode->i_mode)) {
  30                         if (arg)
  31                                 return reiserfs_unpack(inode, filp);
  32                         else
  33                                 return 0;
  34                 } else
  35                         return -ENOTTY;
  36                 /* following two cases are taken from fs/ext2/ioctl.c by Remy
  37                    Card (card@masi.ibp.fr) */
  38         case REISERFS_IOC_GETFLAGS:
  39                 if (!reiserfs_attrs(inode->i_sb))
  40                         return -ENOTTY;
  41
  42                 flags = REISERFS_I(inode)->i_attrs;
  43                 i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
  44                 return put_user(flags, (int __user *)arg);
  45         case REISERFS_IOC_SETFLAGS:{
  46                         if (!reiserfs_attrs(inode->i_sb))
  47                                 return -ENOTTY;
  48
  49                         if (IS_RDONLY(inode))
  50                                 return -EROFS;
  51
  52                         if ((current->fsuid != inode->i_uid)
  53                             && !capable(CAP_FOWNER))
  54                                 return -EPERM;
  55
  56                         if (get_user(flags, (int __user *)arg))
  57                                 return -EFAULT;
  58
  59                         if (((flags ^ REISERFS_I(inode)->
  60                               i_attrs) & (REISERFS_IMMUTABLE_FL |
  61                                           REISERFS_APPEND_FL))
  62                             && !capable(CAP_LINUX_IMMUTABLE))
  63                                 return -EPERM;
  64
  65                         if ((flags & REISERFS_NOTAIL_FL) &&
  66                             S_ISREG(inode->i_mode)) {
  67                                 int result;
  68
  69                                 result = reiserfs_unpack(inode, filp);
  70                                 if (result)
  71                                         return result;
  72                         }
  73                         sd_attrs_to_i_attrs(flags, inode);
  74                         REISERFS_I(inode)->i_attrs = flags;
  75                         inode->i_ctime = CURRENT_TIME_SEC;
  76                         mark_inode_dirty(inode);
  77                         return 0;
  78                 }
  79         case REISERFS_IOC_GETVERSION:
  80                 return put_user(inode->i_generation, (int __user *)arg);
  81         case REISERFS_IOC_SETVERSION:
  82                 if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  83                         return -EPERM;
  84                 if (IS_RDONLY(inode))
  85                         return -EROFS;
  86                 if (get_user(inode->i_generation, (int __user *)arg))
  87                         return -EFAULT;
  88                 inode->i_ctime = CURRENT_TIME_SEC;
  89                 mark_inode_dirty(inode);
  90                 return 0;
  91         default:
  92                 return -ENOTTY;
  93         }
  94 }
  95
  96 /*
  97 ** reiserfs_unpack
  98 ** Function try to convert tail from direct item into indirect.
  99 ** It set up nopack attribute in the REISERFS_I(inode)->nopack
 100 */
 101 static int reiserfs_unpack(struct inode *inode, struct file *filp)
 102 {
 103         int retval = 0;
 104         int index;
 105         struct page *page;
 106         struct address_space *mapping;
 107         unsigned long write_from;
 108         unsigned long blocksize = inode->i_sb->s_blocksize;
 109
 110         if (inode->i_size == 0) {
 111                 REISERFS_I(inode)->i_flags |= i_nopack_mask;
 112                 return 0;
 113         }
 114         /* ioctl already done */
 115         if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
 116                 return 0;
 117         }
 118         reiserfs_write_lock(inode->i_sb);
 119
 120         /* we need to make sure nobody is changing the file size beneath
 121          ** us
 122          */
 123         down(&inode->i_sem);
 124
 125         write_from = inode->i_size & (blocksize - 1);
 126         /* if we are on a block boundary, we are already unpacked.  */
 127         if (write_from == 0) {
 128                 REISERFS_I(inode)->i_flags |= i_nopack_mask;
 129                 goto out;
 130         }
 131
 132         /* we unpack by finding the page with the tail, and calling
 133          ** reiserfs_prepare_write on that page.  This will force a
 134          ** reiserfs_get_block to unpack the tail for us.
 135          */
 136         index = inode->i_size >> PAGE_CACHE_SHIFT;
 137         mapping = inode->i_mapping;
 138         page = grab_cache_page(mapping, index);
 139         retval = -ENOMEM;
 140         if (!page) {
 141                 goto out;
 142         }
 143         retval =
 144             mapping->a_ops->prepare_write(NULL, page, write_from, write_from);
 145         if (retval)
 146                 goto out_unlock;
 147
 148         /* conversion can change page contents, must flush */
 149         flush_dcache_page(page);
 150         retval =
 151             mapping->a_ops->commit_write(NULL, page, write_from, write_from);
 152         REISERFS_I(inode)->i_flags |= i_nopack_mask;
 153
 154       out_unlock:
 155         unlock_page(page);
 156         page_cache_release(page);
 157
 158       out:
 159         up(&inode->i_sem);
 160         reiserfs_write_unlock(inode->i_sb);
 161         return retval;
 162 }