/spare/repo/libata-dev branch 'v2.6.13'
[linux-2.6] / 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 }