ioctl.c revision 52b499c438ff60991eb3855ca090782569b3e8cf 
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#include <linux/compat.h>
13
14static int reiserfs_unpack(struct inode *inode, struct file *filp);
15
16/*
17** reiserfs_ioctl - handler for ioctl for inode
18** supported commands:
19**  1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
20**                           and prevent packing file (argument arg has to be non-zero)
21**  2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
22**  3) That's all for a while ...
23*/
24int reiserfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
25		   unsigned long arg)
26{
27	unsigned int flags;
28
29	switch (cmd) {
30	case REISERFS_IOC_UNPACK:
31		if (S_ISREG(inode->i_mode)) {
32			if (arg)
33				return reiserfs_unpack(inode, filp);
34			else
35				return 0;
36		} else
37			return -ENOTTY;
38		/* following two cases are taken from fs/ext2/ioctl.c by Remy
39		   Card (card@masi.ibp.fr) */
40	case REISERFS_IOC_GETFLAGS:
41		if (!reiserfs_attrs(inode->i_sb))
42			return -ENOTTY;
43
44		flags = REISERFS_I(inode)->i_attrs;
45		i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
46		return put_user(flags, (int __user *)arg);
47	case REISERFS_IOC_SETFLAGS:{
48			if (!reiserfs_attrs(inode->i_sb))
49				return -ENOTTY;
50
51			if (IS_RDONLY(inode))
52				return -EROFS;
53
54			if ((current->fsuid != inode->i_uid)
55			    && !capable(CAP_FOWNER))
56				return -EPERM;
57
58			if (get_user(flags, (int __user *)arg))
59				return -EFAULT;
60
61			if (((flags ^ REISERFS_I(inode)->
62			      i_attrs) & (REISERFS_IMMUTABLE_FL |
63					  REISERFS_APPEND_FL))
64			    && !capable(CAP_LINUX_IMMUTABLE))
65				return -EPERM;
66
67			if ((flags & REISERFS_NOTAIL_FL) &&
68			    S_ISREG(inode->i_mode)) {
69				int result;
70
71				result = reiserfs_unpack(inode, filp);
72				if (result)
73					return result;
74			}
75			sd_attrs_to_i_attrs(flags, inode);
76			REISERFS_I(inode)->i_attrs = flags;
77			inode->i_ctime = CURRENT_TIME_SEC;
78			mark_inode_dirty(inode);
79			return 0;
80		}
81	case REISERFS_IOC_GETVERSION:
82		return put_user(inode->i_generation, (int __user *)arg);
83	case REISERFS_IOC_SETVERSION:
84		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
85			return -EPERM;
86		if (IS_RDONLY(inode))
87			return -EROFS;
88		if (get_user(inode->i_generation, (int __user *)arg))
89			return -EFAULT;
90		inode->i_ctime = CURRENT_TIME_SEC;
91		mark_inode_dirty(inode);
92		return 0;
93	default:
94		return -ENOTTY;
95	}
96}
97
98#ifdef CONFIG_COMPAT
99long reiserfs_compat_ioctl(struct file *file, unsigned int cmd,
100				unsigned long arg)
101{
102	struct inode *inode = file->f_dentry->d_inode;
103	int ret;
104
105	/* These are just misnamed, they actually get/put from/to user an int */
106	switch (cmd) {
107	case REISERFS_IOC32_UNPACK:
108		cmd = REISERFS_IOC_UNPACK;
109		break;
110	case REISERFS_IOC32_GETFLAGS:
111		cmd = REISERFS_IOC_GETFLAGS;
112		break;
113	case REISERFS_IOC32_SETFLAGS:
114		cmd = REISERFS_IOC_SETFLAGS;
115		break;
116	case REISERFS_IOC32_GETVERSION:
117		cmd = REISERFS_IOC_GETVERSION;
118		break;
119	case REISERFS_IOC32_SETVERSION:
120		cmd = REISERFS_IOC_SETVERSION;
121		break;
122	default:
123		return -ENOIOCTLCMD;
124	}
125	lock_kernel();
126	ret = reiserfs_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
127	unlock_kernel();
128	return ret;
129}
130#endif
131
132/*
133** reiserfs_unpack
134** Function try to convert tail from direct item into indirect.
135** It set up nopack attribute in the REISERFS_I(inode)->nopack
136*/
137static int reiserfs_unpack(struct inode *inode, struct file *filp)
138{
139	int retval = 0;
140	int index;
141	struct page *page;
142	struct address_space *mapping;
143	unsigned long write_from;
144	unsigned long blocksize = inode->i_sb->s_blocksize;
145
146	if (inode->i_size == 0) {
147		REISERFS_I(inode)->i_flags |= i_nopack_mask;
148		return 0;
149	}
150	/* ioctl already done */
151	if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
152		return 0;
153	}
154
155	/* we need to make sure nobody is changing the file size beneath
156	 ** us
157	 */
158	mutex_lock(&inode->i_mutex);
159	reiserfs_write_lock(inode->i_sb);
160
161	write_from = inode->i_size & (blocksize - 1);
162	/* if we are on a block boundary, we are already unpacked.  */
163	if (write_from == 0) {
164		REISERFS_I(inode)->i_flags |= i_nopack_mask;
165		goto out;
166	}
167
168	/* we unpack by finding the page with the tail, and calling
169	 ** reiserfs_prepare_write on that page.  This will force a
170	 ** reiserfs_get_block to unpack the tail for us.
171	 */
172	index = inode->i_size >> PAGE_CACHE_SHIFT;
173	mapping = inode->i_mapping;
174	page = grab_cache_page(mapping, index);
175	retval = -ENOMEM;
176	if (!page) {
177		goto out;
178	}
179	retval =
180	    mapping->a_ops->prepare_write(NULL, page, write_from, write_from);
181	if (retval)
182		goto out_unlock;
183
184	/* conversion can change page contents, must flush */
185	flush_dcache_page(page);
186	retval =
187	    mapping->a_ops->commit_write(NULL, page, write_from, write_from);
188	REISERFS_I(inode)->i_flags |= i_nopack_mask;
189
190      out_unlock:
191	unlock_page(page);
192	page_cache_release(page);
193
194      out:
195	mutex_unlock(&inode->i_mutex);
196	reiserfs_write_unlock(inode->i_sb);
197	return retval;
198}
199