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
29static 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 > 0) {
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 */
67void 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
121void 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
179static 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 */
202void 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;
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_ALLOCDECS >> 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			if (elen)
264				indirect_ext_len =
265					(elen + sb->s_blocksize - 1) >>
266					sb->s_blocksize_bits;
267			else
268				indirect_ext_len = 1;
269		} else {
270			extent_trunc(inode, &epos, &eloc, etype, elen, 0);
271			epos.offset += adsize;
272		}
273	}
274
275	if (indirect_ext_len) {
276		BUG_ON(!epos.bh);
277		udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
278	} else if (!epos.bh) {
279		iinfo->i_lenAlloc = lenalloc;
280		mark_inode_dirty(inode);
281	} else
282		udf_update_alloc_ext_desc(inode, &epos, lenalloc);
283	iinfo->i_lenExtents = inode->i_size;
284
285	brelse(epos.bh);
286}
287