ioctl.c revision 16f7e0fe2ecc30f30652e8185e1772cdebe39109 
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
13static 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*/
23int 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*/
102static 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}
164