xref: /openbmc/linux/fs/udf/file.c (revision e382588b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * file.c
4  *
5  * PURPOSE
6  *  File handling routines for the OSTA-UDF(tm) filesystem.
7  *
8  * COPYRIGHT
9  *  (C) 1998-1999 Dave Boynton
10  *  (C) 1998-2004 Ben Fennema
11  *  (C) 1999-2000 Stelias Computing Inc
12  *
13  * HISTORY
14  *
15  *  10/02/98 dgb  Attempt to integrate into udf.o
16  *  10/07/98      Switched to using generic_readpage, etc., like isofs
17  *                And it works!
18  *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
19  *                ICBTAG_FLAG_AD_IN_ICB.
20  *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
21  *  05/12/99      Preliminary file write support
22  */
23 
24 #include "udfdecl.h"
25 #include <linux/fs.h>
26 #include <linux/uaccess.h>
27 #include <linux/kernel.h>
28 #include <linux/string.h> /* memset */
29 #include <linux/capability.h>
30 #include <linux/errno.h>
31 #include <linux/pagemap.h>
32 #include <linux/uio.h>
33 
34 #include "udf_i.h"
35 #include "udf_sb.h"
36 
udf_page_mkwrite(struct vm_fault * vmf)37 static vm_fault_t udf_page_mkwrite(struct vm_fault *vmf)
38 {
39 	struct vm_area_struct *vma = vmf->vma;
40 	struct inode *inode = file_inode(vma->vm_file);
41 	struct address_space *mapping = inode->i_mapping;
42 	struct page *page = vmf->page;
43 	loff_t size;
44 	unsigned int end;
45 	vm_fault_t ret = VM_FAULT_LOCKED;
46 	int err;
47 
48 	sb_start_pagefault(inode->i_sb);
49 	file_update_time(vma->vm_file);
50 	filemap_invalidate_lock_shared(mapping);
51 	lock_page(page);
52 	size = i_size_read(inode);
53 	if (page->mapping != inode->i_mapping || page_offset(page) >= size) {
54 		unlock_page(page);
55 		ret = VM_FAULT_NOPAGE;
56 		goto out_unlock;
57 	}
58 	/* Space is already allocated for in-ICB file */
59 	if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
60 		goto out_dirty;
61 	if (page->index == size >> PAGE_SHIFT)
62 		end = size & ~PAGE_MASK;
63 	else
64 		end = PAGE_SIZE;
65 	err = __block_write_begin(page, 0, end, udf_get_block);
66 	if (err) {
67 		unlock_page(page);
68 		ret = vmf_fs_error(err);
69 		goto out_unlock;
70 	}
71 
72 	block_commit_write(page, 0, end);
73 out_dirty:
74 	set_page_dirty(page);
75 	wait_for_stable_page(page);
76 out_unlock:
77 	filemap_invalidate_unlock_shared(mapping);
78 	sb_end_pagefault(inode->i_sb);
79 	return ret;
80 }
81 
82 static const struct vm_operations_struct udf_file_vm_ops = {
83 	.fault		= filemap_fault,
84 	.map_pages	= filemap_map_pages,
85 	.page_mkwrite	= udf_page_mkwrite,
86 };
87 
udf_file_write_iter(struct kiocb * iocb,struct iov_iter * from)88 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
89 {
90 	ssize_t retval;
91 	struct file *file = iocb->ki_filp;
92 	struct inode *inode = file_inode(file);
93 	struct udf_inode_info *iinfo = UDF_I(inode);
94 
95 	inode_lock(inode);
96 
97 	retval = generic_write_checks(iocb, from);
98 	if (retval <= 0)
99 		goto out;
100 
101 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
102 	    inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
103 				 iocb->ki_pos + iov_iter_count(from))) {
104 		filemap_invalidate_lock(inode->i_mapping);
105 		retval = udf_expand_file_adinicb(inode);
106 		filemap_invalidate_unlock(inode->i_mapping);
107 		if (retval)
108 			goto out;
109 	}
110 
111 	retval = __generic_file_write_iter(iocb, from);
112 out:
113 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0) {
114 		down_write(&iinfo->i_data_sem);
115 		iinfo->i_lenAlloc = inode->i_size;
116 		up_write(&iinfo->i_data_sem);
117 	}
118 	inode_unlock(inode);
119 
120 	if (retval > 0) {
121 		mark_inode_dirty(inode);
122 		retval = generic_write_sync(iocb, retval);
123 	}
124 
125 	return retval;
126 }
127 
udf_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)128 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
129 {
130 	struct inode *inode = file_inode(filp);
131 	long old_block, new_block;
132 	int result;
133 
134 	if (file_permission(filp, MAY_READ) != 0) {
135 		udf_debug("no permission to access inode %lu\n", inode->i_ino);
136 		return -EPERM;
137 	}
138 
139 	if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
140 		     (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
141 		udf_debug("invalid argument to udf_ioctl\n");
142 		return -EINVAL;
143 	}
144 
145 	switch (cmd) {
146 	case UDF_GETVOLIDENT:
147 		if (copy_to_user((char __user *)arg,
148 				 UDF_SB(inode->i_sb)->s_volume_ident, 32))
149 			return -EFAULT;
150 		return 0;
151 	case UDF_RELOCATE_BLOCKS:
152 		if (!capable(CAP_SYS_ADMIN))
153 			return -EPERM;
154 		if (get_user(old_block, (long __user *)arg))
155 			return -EFAULT;
156 		result = udf_relocate_blocks(inode->i_sb,
157 						old_block, &new_block);
158 		if (result == 0)
159 			result = put_user(new_block, (long __user *)arg);
160 		return result;
161 	case UDF_GETEASIZE:
162 		return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
163 	case UDF_GETEABLOCK:
164 		return copy_to_user((char __user *)arg,
165 				    UDF_I(inode)->i_data,
166 				    UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
167 	default:
168 		return -ENOIOCTLCMD;
169 	}
170 
171 	return 0;
172 }
173 
udf_release_file(struct inode * inode,struct file * filp)174 static int udf_release_file(struct inode *inode, struct file *filp)
175 {
176 	if (filp->f_mode & FMODE_WRITE &&
177 	    atomic_read(&inode->i_writecount) == 1) {
178 		/*
179 		 * Grab i_mutex to avoid races with writes changing i_size
180 		 * while we are running.
181 		 */
182 		inode_lock(inode);
183 		down_write(&UDF_I(inode)->i_data_sem);
184 		udf_discard_prealloc(inode);
185 		udf_truncate_tail_extent(inode);
186 		up_write(&UDF_I(inode)->i_data_sem);
187 		inode_unlock(inode);
188 	}
189 	return 0;
190 }
191 
udf_file_mmap(struct file * file,struct vm_area_struct * vma)192 static int udf_file_mmap(struct file *file, struct vm_area_struct *vma)
193 {
194 	file_accessed(file);
195 	vma->vm_ops = &udf_file_vm_ops;
196 
197 	return 0;
198 }
199 
200 const struct file_operations udf_file_operations = {
201 	.read_iter		= generic_file_read_iter,
202 	.unlocked_ioctl		= udf_ioctl,
203 	.open			= generic_file_open,
204 	.mmap			= udf_file_mmap,
205 	.write_iter		= udf_file_write_iter,
206 	.release		= udf_release_file,
207 	.fsync			= generic_file_fsync,
208 	.splice_read		= filemap_splice_read,
209 	.splice_write		= iter_file_splice_write,
210 	.llseek			= generic_file_llseek,
211 };
212 
udf_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)213 static int udf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
214 		       struct iattr *attr)
215 {
216 	struct inode *inode = d_inode(dentry);
217 	struct super_block *sb = inode->i_sb;
218 	int error;
219 
220 	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
221 	if (error)
222 		return error;
223 
224 	if ((attr->ia_valid & ATTR_UID) &&
225 	    UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
226 	    !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
227 		return -EPERM;
228 	if ((attr->ia_valid & ATTR_GID) &&
229 	    UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
230 	    !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
231 		return -EPERM;
232 
233 	if ((attr->ia_valid & ATTR_SIZE) &&
234 	    attr->ia_size != i_size_read(inode)) {
235 		filemap_invalidate_lock(inode->i_mapping);
236 		error = udf_setsize(inode, attr->ia_size);
237 		filemap_invalidate_unlock(inode->i_mapping);
238 		if (error)
239 			return error;
240 	}
241 
242 	if (attr->ia_valid & ATTR_MODE)
243 		udf_update_extra_perms(inode, attr->ia_mode);
244 
245 	setattr_copy(&nop_mnt_idmap, inode, attr);
246 	mark_inode_dirty(inode);
247 	return 0;
248 }
249 
250 const struct inode_operations udf_file_inode_operations = {
251 	.setattr		= udf_setattr,
252 };
253