fs/reiserfs/ioctl.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4
   5 #include <linux/capability.h>
   6 #include <linux/fs.h>
   7 #include <linux/reiserfs_fs.h>
   8 #include <linux/time.h>
   9 #include <asm/uaccess.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/smp_lock.h>
  12
  13 static int reiserfs_unpack(struct inode *inode, struct file *filp);
  14
  15 /*
  16 ** reiserfs_ioctl - handler for ioctl for inode
  17 ** supported commands:
  18 **  1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
  19 **                           and prevent packing file (argument arg has to be non-zero)
  20 **  2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
  21 **  3) That's all for a while ...
  22 */
  23 int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
  24                    unsigned long arg)
  25 {
  26         unsigned int flags;
  27
  28         switch (cmd) {
  29         case REISERFS_IOC_UNPACK:
  30                 if (S_ISREG(inode->i_mode)) {
  31                         if (arg)
  32                                 return reiserfs_unpack(inode, filp);
  33                         else
  34                                 return 0;
  35                 } else
  36                         return -ENOTTY;
  37                 /* following two cases are taken from fs/ext2/ioctl.c by Remy
  38                    Card (card@masi.ibp.fr) */
  39         case REISERFS_IOC_GETFLAGS:
  40                 if (!reiserfs_attrs(inode->i_sb))
  41                         return -ENOTTY;
  42
  43                 flags = REISERFS_I(inode)->i_attrs;
  44                 i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
  45                 return put_user(flags, (int __user *)arg);
  46         case REISERFS_IOC_SETFLAGS:{
  47                         if (!reiserfs_attrs(inode->i_sb))
  48                                 return -ENOTTY;
  49
  50                         if (IS_RDONLY(inode))
  51                                 return -EROFS;
  52
  53                         if ((current->fsuid != inode->i_uid)
  54                             && !capable(CAP_FOWNER))
  55                                 return -EPERM;
  56
  57                         if (get_user(flags, (int __user *)arg))
  58                                 return -EFAULT;
  59
  60                         if (((flags ^ REISERFS_I(inode)->
  61                               i_attrs) & (REISERFS_IMMUTABLE_FL |
  62                                           REISERFS_APPEND_FL))
  63                             && !capable(CAP_LINUX_IMMUTABLE))
  64                                 return -EPERM;
  65
  66                         if ((flags & REISERFS_NOTAIL_FL) &&
  67                             S_ISREG(inode->i_mode)) {
  68                                 int result;
  69
  70                                 result = reiserfs_unpack(inode, filp);
  71                                 if (result)
  72                                         return result;
  73                         }
  74                         sd_attrs_to_i_attrs(flags, inode);
  75                         REISERFS_I(inode)->i_attrs = flags;
  76                         inode->i_ctime = CURRENT_TIME_SEC;
  77                         mark_inode_dirty(inode);
  78                         return 0;
  79                 }
  80         case REISERFS_IOC_GETVERSION:
  81                 return put_user(inode->i_generation, (int __user *)arg);
  82         case REISERFS_IOC_SETVERSION:
  83                 if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
  84                         return -EPERM;
  85                 if (IS_RDONLY(inode))
  86                         return -EROFS;
  87                 if (get_user(inode->i_generation, (int __user *)arg))
  88                         return -EFAULT;
  89                 inode->i_ctime = CURRENT_TIME_SEC;
  90                 mark_inode_dirty(inode);
  91                 return 0;
  92         default:
  93                 return -ENOTTY;
  94         }
  95 }
  96
  97 /*
  98 ** reiserfs_unpack
  99 ** Function try to convert tail from direct item into indirect.
 100 ** It set up nopack attribute in the REISERFS_I(inode)->nopack
 101 */
 102 static int reiserfs_unpack(struct inode *inode, struct file *filp)
 103 {
 104         int retval = 0;
 105         int index;
 106         struct page *page;
 107         struct address_space *mapping;
 108         unsigned long write_from;
 109         unsigned long blocksize = inode->i_sb->s_blocksize;
 110
 111         if (inode->i_size == 0) {
 112                 REISERFS_I(inode)->i_flags |= i_nopack_mask;
 113                 return 0;
 114         }
 115         /* ioctl already done */
 116         if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
 117                 return 0;
 118         }
 119         reiserfs_write_lock(inode->i_sb);
 120
 121         /* we need to make sure nobody is changing the file size beneath
 122          ** us
 123          */
 124         mutex_lock(&inode->i_mutex);
 125
 126         write_from = inode->i_size & (blocksize - 1);
 127         /* if we are on a block boundary, we are already unpacked.  */
 128         if (write_from == 0) {
 129                 REISERFS_I(inode)->i_flags |= i_nopack_mask;
 130                 goto out;
 131         }
 132
 133         /* we unpack by finding the page with the tail, and calling
 134          ** reiserfs_prepare_write on that page.  This will force a
 135          ** reiserfs_get_block to unpack the tail for us.
 136          */
 137         index = inode->i_size >> PAGE_CACHE_SHIFT;
 138         mapping = inode->i_mapping;
 139         page = grab_cache_page(mapping, index);
 140         retval = -ENOMEM;
 141         if (!page) {
 142                 goto out;
 143         }
 144         retval =
 145             mapping->a_ops->prepare_write(NULL, page, write_from, write_from);
 146         if (retval)
 147                 goto out_unlock;
 148
 149         /* conversion can change page contents, must flush */
 150         flush_dcache_page(page);
 151         retval =
 152             mapping->a_ops->commit_write(NULL, page, write_from, write_from);
 153         REISERFS_I(inode)->i_flags |= i_nopack_mask;
 154
 155       out_unlock:
 156         unlock_page(page);
 157         page_cache_release(page);
 158
 159       out:
 160         mutex_unlock(&inode->i_mutex);
 161         reiserfs_write_unlock(inode->i_sb);
 162         return retval;
 163 }