Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...
[linux-2.6] / fs / udf / truncate.c
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 #include <linux/udf_fs.h>
26 #include <linux/buffer_head.h>
27
28 #include "udf_i.h"
29 #include "udf_sb.h"
30
31 static void extent_trunc(struct inode * inode, struct extent_position *epos,
32         kernel_lb_addr eloc, int8_t etype, uint32_t elen, uint32_t nelen)
33 {
34         kernel_lb_addr neloc = { 0, 0 };
35         int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
36         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
37
38         if (nelen)
39         {
40                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
41                 {
42                         udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
43                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
44                 }
45                 else
46                         neloc = eloc;
47                 nelen = (etype << 30) | nelen;
48         }
49
50         if (elen != nelen)
51         {
52                 udf_write_aext(inode, epos, neloc, nelen, 0);
53                 if (last_block - first_block > 0)
54                 {
55                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
56                                 mark_inode_dirty(inode);
57
58                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
59                                 udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
60                 }
61         }
62 }
63
64 void udf_discard_prealloc(struct inode * inode)
65 {
66         struct extent_position epos = { NULL, 0, {0, 0}};
67         kernel_lb_addr eloc;
68         uint32_t elen, nelen;
69         uint64_t lbcount = 0;
70         int8_t etype = -1, netype;
71         int adsize;
72
73         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
74                 inode->i_size == UDF_I_LENEXTENTS(inode))
75                 return;
76
77         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
78                 adsize = sizeof(short_ad);
79         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
80                 adsize = sizeof(long_ad);
81         else
82                 adsize = 0;
83
84         epos.block = UDF_I_LOCATION(inode);
85
86         /* Find the last extent in the file */
87         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1)
88         {
89                 etype = netype;
90                 lbcount += elen;
91                 if (lbcount > inode->i_size && lbcount - elen < inode->i_size)
92                 {
93                         WARN_ON(lbcount - inode->i_size >= inode->i_sb->s_blocksize);
94                         nelen = elen - (lbcount - inode->i_size);
95                         epos.offset -= adsize;
96                         extent_trunc(inode, &epos, eloc, etype, elen, nelen);
97                         epos.offset += adsize;
98                         lbcount = inode->i_size;
99                 }
100         }
101         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
102                 epos.offset -= adsize;
103                 lbcount -= elen;
104                 extent_trunc(inode, &epos, eloc, etype, elen, 0);
105                 if (!epos.bh)
106                 {
107                         UDF_I_LENALLOC(inode) = epos.offset - udf_file_entry_alloc_offset(inode);
108                         mark_inode_dirty(inode);
109                 }
110                 else
111                 {
112                         struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
113                         aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc));
114                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
115                                 udf_update_tag(epos.bh->b_data, epos.offset);
116                         else
117                                 udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
118                         mark_buffer_dirty_inode(epos.bh, inode);
119                 }
120         }
121         UDF_I_LENEXTENTS(inode) = lbcount;
122
123         WARN_ON(lbcount != inode->i_size);
124         brelse(epos.bh);
125 }
126
127 void udf_truncate_extents(struct inode * inode)
128 {
129         struct extent_position epos;
130         kernel_lb_addr eloc, neloc = { 0, 0 };
131         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
132         int8_t etype;
133         struct super_block *sb = inode->i_sb;
134         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
135         loff_t byte_offset;
136         int adsize;
137
138         if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
139                 adsize = sizeof(short_ad);
140         else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
141                 adsize = sizeof(long_ad);
142         else
143                 BUG();
144
145         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
146         byte_offset = (offset << sb->s_blocksize_bits) + (inode->i_size & (sb->s_blocksize-1));
147         if (etype != -1)
148         {
149                 epos.offset -= adsize;
150                 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
151                 epos.offset += adsize;
152                 if (byte_offset)
153                         lenalloc = epos.offset;
154                 else
155                         lenalloc = epos.offset - adsize;
156
157                 if (!epos.bh)
158                         lenalloc -= udf_file_entry_alloc_offset(inode);
159                 else
160                         lenalloc -= sizeof(struct allocExtDesc);
161
162                 while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1)
163                 {
164                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
165                         {
166                                 udf_write_aext(inode, &epos, neloc, nelen, 0);
167                                 if (indirect_ext_len)
168                                 {
169                                         /* We managed to free all extents in the
170                                          * indirect extent - free it too */
171                                         if (!epos.bh)
172                                                 BUG();
173                                         udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len);
174                                 }
175                                 else
176                                 {
177                                         if (!epos.bh)
178                                         {
179                                                 UDF_I_LENALLOC(inode) = lenalloc;
180                                                 mark_inode_dirty(inode);
181                                         }
182                                         else
183                                         {
184                                                 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
185                                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
186                                                 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201)
187                                                         udf_update_tag(epos.bh->b_data, lenalloc +
188                                                                 sizeof(struct allocExtDesc));
189                                                 else
190                                                         udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
191                                                 mark_buffer_dirty_inode(epos.bh, inode);
192                                         }
193                                 }
194                                 brelse(epos.bh);
195                                 epos.offset = sizeof(struct allocExtDesc);
196                                 epos.block = eloc;
197                                 epos.bh = udf_tread(sb, udf_get_lb_pblock(sb, eloc, 0));
198                                 if (elen)
199                                         indirect_ext_len = (elen +
200                                                 sb->s_blocksize - 1) >>
201                                                 sb->s_blocksize_bits;
202                                 else
203                                         indirect_ext_len = 1;
204                         }
205                         else
206                         {
207                                 extent_trunc(inode, &epos, eloc, etype, elen, 0);
208                                 epos.offset += adsize;
209                         }
210                 }
211
212                 if (indirect_ext_len)
213                 {
214                         if (!epos.bh)
215                                 BUG();
216                         udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len);
217                 }
218                 else
219                 {
220                         if (!epos.bh)
221                         {
222                                 UDF_I_LENALLOC(inode) = lenalloc;
223                                 mark_inode_dirty(inode);
224                         }
225                         else
226                         {
227                                 struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
228                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
229                                 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201)
230                                         udf_update_tag(epos.bh->b_data, lenalloc +
231                                                 sizeof(struct allocExtDesc));
232                                 else
233                                         udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
234                                 mark_buffer_dirty_inode(epos.bh, inode);
235                         }
236                 }
237         }
238         else if (inode->i_size)
239         {
240                 if (byte_offset)
241                 {
242                         kernel_long_ad extent;
243
244                         /*
245                          *  OK, there is not extent covering inode->i_size and
246                          *  no extent above inode->i_size => truncate is
247                          *  extending the file by 'offset' blocks.
248                          */
249                         if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) ||
250                             (epos.bh && epos.offset == sizeof(struct allocExtDesc))) {
251                                 /* File has no extents at all or has empty last
252                                  * indirect extent! Create a fake extent... */
253                                 extent.extLocation.logicalBlockNum = 0;
254                                 extent.extLocation.partitionReferenceNum = 0;
255                                 extent.extLength = EXT_NOT_RECORDED_NOT_ALLOCATED;
256                         }
257                         else {
258                                 epos.offset -= adsize;
259                                 etype = udf_next_aext(inode, &epos,
260                                         &extent.extLocation, &extent.extLength, 0);
261                                 extent.extLength |= etype << 30;
262                         }
263                         udf_extend_file(inode, &epos, &extent, offset+((inode->i_size & (sb->s_blocksize-1)) != 0));
264                 }
265         }
266         UDF_I_LENEXTENTS(inode) = inode->i_size;
267
268         brelse(epos.bh);
269 }