1 /*
2  * truncate.c
3  *
4  * PURPOSE
5  *	Truncate handling routines for the OSTA-UDF(tm) filesystem.
6  *
7  * COPYRIGHT
8  *	This file is distributed under the terms of the GNU General Public
9  *	License (GPL). Copies of the GPL can be obtained from:
10  *		ftp://prep.ai.mit.edu/pub/gnu/GPL
11  *	Each contributing author retains all rights to their own work.
12  *
13  *  (C) 1999-2004 Ben Fennema
14  *  (C) 1999 Stelias Computing Inc
15  *
16  * HISTORY
17  *
18  *  02/24/99 blf  Created.
19  *
20  */
21 
22 #include "udfdecl.h"
23 #include <linux/fs.h>
24 #include <linux/mm.h>
25 
26 #include "udf_i.h"
27 #include "udf_sb.h"
28 
extent_trunc(struct inode * inode,struct extent_position * epos,struct kernel_lb_addr * eloc,int8_t etype,uint32_t elen,uint32_t nelen)29 static void extent_trunc(struct inode *inode, struct extent_position *epos,
30 			 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
31 			 uint32_t nelen)
32 {
33 	struct kernel_lb_addr neloc = {};
34 	int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
35 		inode->i_sb->s_blocksize_bits;
36 	int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
37 		inode->i_sb->s_blocksize_bits;
38 
39 	if (nelen) {
40 		if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
41 			udf_free_blocks(inode->i_sb, inode, eloc, 0,
42 					last_block);
43 			etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
44 		} else
45 			neloc = *eloc;
46 		nelen = (etype << 30) | nelen;
47 	}
48 
49 	if (elen != nelen) {
50 		udf_write_aext(inode, epos, &neloc, nelen, 0);
51 		if (last_block > first_block) {
52 			if (etype == (EXT_RECORDED_ALLOCATED >> 30))
53 				mark_inode_dirty(inode);
54 
55 			if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
56 				udf_free_blocks(inode->i_sb, inode, eloc,
57 						first_block,
58 						last_block - first_block);
59 		}
60 	}
61 }
62 
63 /*
64  * Truncate the last extent to match i_size. This function assumes
65  * that preallocation extent is already truncated.
66  */
udf_truncate_tail_extent(struct inode * inode)67 void udf_truncate_tail_extent(struct inode *inode)
68 {
69 	struct extent_position epos = {};
70 	struct kernel_lb_addr eloc;
71 	uint32_t elen, nelen;
72 	uint64_t lbcount = 0;
73 	int8_t etype = -1, netype;
74 	int adsize;
75 	struct udf_inode_info *iinfo = UDF_I(inode);
76 
77 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
78 	    inode->i_size == iinfo->i_lenExtents)
79 		return;
80 	/* Are we going to delete the file anyway? */
81 	if (inode->i_nlink == 0)
82 		return;
83 
84 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
85 		adsize = sizeof(struct short_ad);
86 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
87 		adsize = sizeof(struct long_ad);
88 	else
89 		BUG();
90 
91 	/* Find the last extent in the file */
92 	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
93 		etype = netype;
94 		lbcount += elen;
95 		if (lbcount > inode->i_size) {
96 			if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
97 				udf_warn(inode->i_sb,
98 					 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
99 					 (unsigned)inode->i_ino,
100 					 (long long)inode->i_size,
101 					 (long long)lbcount,
102 					 (unsigned)eloc.logicalBlockNum,
103 					 (unsigned)elen);
104 			nelen = elen - (lbcount - inode->i_size);
105 			epos.offset -= adsize;
106 			extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
107 			epos.offset += adsize;
108 			if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
109 				udf_err(inode->i_sb,
110 					"Extent after EOF in inode %u\n",
111 					(unsigned)inode->i_ino);
112 			break;
113 		}
114 	}
115 	/* This inode entry is in-memory only and thus we don't have to mark
116 	 * the inode dirty */
117 	iinfo->i_lenExtents = inode->i_size;
118 	brelse(epos.bh);
119 }
120 
udf_discard_prealloc(struct inode * inode)121 void udf_discard_prealloc(struct inode *inode)
122 {
123 	struct extent_position epos = { NULL, 0, {0, 0} };
124 	struct kernel_lb_addr eloc;
125 	uint32_t elen;
126 	uint64_t lbcount = 0;
127 	int8_t etype = -1, netype;
128 	int adsize;
129 	struct udf_inode_info *iinfo = UDF_I(inode);
130 
131 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
132 	    inode->i_size == iinfo->i_lenExtents)
133 		return;
134 
135 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
136 		adsize = sizeof(struct short_ad);
137 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
138 		adsize = sizeof(struct long_ad);
139 	else
140 		adsize = 0;
141 
142 	epos.block = iinfo->i_location;
143 
144 	/* Find the last extent in the file */
145 	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
146 		etype = netype;
147 		lbcount += elen;
148 	}
149 	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
150 		epos.offset -= adsize;
151 		lbcount -= elen;
152 		extent_trunc(inode, &epos, &eloc, etype, elen, 0);
153 		if (!epos.bh) {
154 			iinfo->i_lenAlloc =
155 				epos.offset -
156 				udf_file_entry_alloc_offset(inode);
157 			mark_inode_dirty(inode);
158 		} else {
159 			struct allocExtDesc *aed =
160 				(struct allocExtDesc *)(epos.bh->b_data);
161 			aed->lengthAllocDescs =
162 				cpu_to_le32(epos.offset -
163 					    sizeof(struct allocExtDesc));
164 			if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
165 			    UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
166 				udf_update_tag(epos.bh->b_data, epos.offset);
167 			else
168 				udf_update_tag(epos.bh->b_data,
169 					       sizeof(struct allocExtDesc));
170 			mark_buffer_dirty_inode(epos.bh, inode);
171 		}
172 	}
173 	/* This inode entry is in-memory only and thus we don't have to mark
174 	 * the inode dirty */
175 	iinfo->i_lenExtents = lbcount;
176 	brelse(epos.bh);
177 }
178 
udf_update_alloc_ext_desc(struct inode * inode,struct extent_position * epos,u32 lenalloc)179 static void udf_update_alloc_ext_desc(struct inode *inode,
180 				      struct extent_position *epos,
181 				      u32 lenalloc)
182 {
183 	struct super_block *sb = inode->i_sb;
184 	struct udf_sb_info *sbi = UDF_SB(sb);
185 
186 	struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
187 	int len = sizeof(struct allocExtDesc);
188 
189 	aed->lengthAllocDescs =	cpu_to_le32(lenalloc);
190 	if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
191 		len += lenalloc;
192 
193 	udf_update_tag(epos->bh->b_data, len);
194 	mark_buffer_dirty_inode(epos->bh, inode);
195 }
196 
197 /*
198  * Truncate extents of inode to inode->i_size. This function can be used only
199  * for making file shorter. For making file longer, udf_extend_file() has to
200  * be used.
201  */
udf_truncate_extents(struct inode * inode)202 int udf_truncate_extents(struct inode *inode)
203 {
204 	struct extent_position epos;
205 	struct kernel_lb_addr eloc, neloc = {};
206 	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
207 	int8_t etype;
208 	struct super_block *sb = inode->i_sb;
209 	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
210 	loff_t byte_offset;
211 	int adsize;
212 	struct udf_inode_info *iinfo = UDF_I(inode);
213 
214 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
215 		adsize = sizeof(struct short_ad);
216 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
217 		adsize = sizeof(struct long_ad);
218 	else
219 		BUG();
220 
221 	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
222 	byte_offset = (offset << sb->s_blocksize_bits) +
223 		(inode->i_size & (sb->s_blocksize - 1));
224 	if (etype == -1) {
225 		/* We should extend the file? */
226 		WARN_ON(byte_offset);
227 		return 0;
228 	}
229 	epos.offset -= adsize;
230 	extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
231 	epos.offset += adsize;
232 	if (byte_offset)
233 		lenalloc = epos.offset;
234 	else
235 		lenalloc = epos.offset - adsize;
236 
237 	if (!epos.bh)
238 		lenalloc -= udf_file_entry_alloc_offset(inode);
239 	else
240 		lenalloc -= sizeof(struct allocExtDesc);
241 
242 	while ((etype = udf_current_aext(inode, &epos, &eloc,
243 					 &elen, 0)) != -1) {
244 		if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
245 			udf_write_aext(inode, &epos, &neloc, nelen, 0);
246 			if (indirect_ext_len) {
247 				/* We managed to free all extents in the
248 				 * indirect extent - free it too */
249 				BUG_ON(!epos.bh);
250 				udf_free_blocks(sb, NULL, &epos.block,
251 						0, indirect_ext_len);
252 			} else if (!epos.bh) {
253 				iinfo->i_lenAlloc = lenalloc;
254 				mark_inode_dirty(inode);
255 			} else
256 				udf_update_alloc_ext_desc(inode,
257 						&epos, lenalloc);
258 			brelse(epos.bh);
259 			epos.offset = sizeof(struct allocExtDesc);
260 			epos.block = eloc;
261 			epos.bh = udf_tread(sb,
262 					udf_get_lb_pblock(sb, &eloc, 0));
263 			/* Error reading indirect block? */
264 			if (!epos.bh)
265 				return -EIO;
266 			if (elen)
267 				indirect_ext_len =
268 					(elen + sb->s_blocksize - 1) >>
269 					sb->s_blocksize_bits;
270 			else
271 				indirect_ext_len = 1;
272 		} else {
273 			extent_trunc(inode, &epos, &eloc, etype, elen, 0);
274 			epos.offset += adsize;
275 		}
276 	}
277 
278 	if (indirect_ext_len) {
279 		BUG_ON(!epos.bh);
280 		udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
281 	} else if (!epos.bh) {
282 		iinfo->i_lenAlloc = lenalloc;
283 		mark_inode_dirty(inode);
284 	} else
285 		udf_update_alloc_ext_desc(inode, &epos, lenalloc);
286 	iinfo->i_lenExtents = inode->i_size;
287 
288 	brelse(epos.bh);
289 	return 0;
290 }
291