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1 | /* |
1 | /* |
2 | * Copyright (c) 2008 Jakub Jermar |
2 | * Copyright (c) 2008 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /** @addtogroup fs |
29 | /** @addtogroup fs |
30 | * @{ |
30 | * @{ |
31 | */ |
31 | */ |
32 | 32 | ||
33 | /** |
33 | /** |
34 | * @file fat_fat.c |
34 | * @file fat_fat.c |
35 | * @brief Functions that manipulate the File Allocation Tables. |
35 | * @brief Functions that manipulate the File Allocation Tables. |
36 | */ |
36 | */ |
37 | 37 | ||
38 | #include "fat_fat.h" |
38 | #include "fat_fat.h" |
39 | #include "fat_dentry.h" |
39 | #include "fat_dentry.h" |
40 | #include "fat.h" |
40 | #include "fat.h" |
41 | #include "../../vfs/vfs.h" |
41 | #include "../../vfs/vfs.h" |
42 | #include <libfs.h> |
42 | #include <libfs.h> |
43 | #include <libblock.h> |
43 | #include <libblock.h> |
44 | #include <errno.h> |
44 | #include <errno.h> |
45 | #include <byteorder.h> |
45 | #include <byteorder.h> |
46 | #include <align.h> |
46 | #include <align.h> |
47 | #include <assert.h> |
47 | #include <assert.h> |
48 | #include <futex.h> |
48 | #include <futex.h> |
49 | 49 | ||
50 | /** |
50 | /** |
51 | * The fat_alloc_lock futex protects all copies of the File Allocation Table |
51 | * The fat_alloc_lock futex protects all copies of the File Allocation Table |
52 | * during allocation of clusters. The lock does not have to be held durring |
52 | * during allocation of clusters. The lock does not have to be held durring |
53 | * deallocation of clusters. |
53 | * deallocation of clusters. |
54 | */ |
54 | */ |
55 | static futex_t fat_alloc_lock = FUTEX_INITIALIZER; |
55 | static futex_t fat_alloc_lock = FUTEX_INITIALIZER; |
56 | 56 | ||
57 | /** Walk the cluster chain. |
57 | /** Walk the cluster chain. |
58 | * |
58 | * |
59 | * @param bs Buffer holding the boot sector for the file. |
59 | * @param bs Buffer holding the boot sector for the file. |
60 | * @param dev_handle Device handle of the device with the file. |
60 | * @param dev_handle Device handle of the device with the file. |
61 | * @param firstc First cluster to start the walk with. |
61 | * @param firstc First cluster to start the walk with. |
62 | * @param penult If non-NULL, output argument hodling the |
62 | * @param lastc If non-NULL, output argument hodling the last cluster number visited. |
63 | * the penultimate cluster visited. |
- | |
64 | * @param ult If non-NULL, output argument holding the |
- | |
65 | * ultimate cluster visited. |
- | |
66 | * @param max_clusters Maximum number of clusters to visit. |
63 | * @param max_clusters Maximum number of clusters to visit. |
67 | * |
64 | * |
68 | * @return Number of clusters seen during the walk. |
65 | * @return Number of clusters seen during the walk. |
69 | */ |
66 | */ |
70 | uint16_t |
67 | uint16_t |
71 | fat_cluster_walk(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc, |
68 | fat_cluster_walk(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc, |
72 | fat_cluster_t *penult, fat_cluster_t *ult, uint16_t max_clusters) |
69 | fat_cluster_t *lastc, uint16_t max_clusters) |
73 | { |
70 | { |
74 | block_t *b; |
71 | block_t *b; |
75 | unsigned bps; |
72 | unsigned bps; |
76 | unsigned rscnt; /* block address of the first FAT */ |
73 | unsigned rscnt; /* block address of the first FAT */ |
77 | uint16_t clusters = 0; |
74 | uint16_t clusters = 0; |
78 | fat_cluster_t clst = firstc; |
75 | fat_cluster_t clst = firstc; |
79 | 76 | ||
80 | bps = uint16_t_le2host(bs->bps); |
77 | bps = uint16_t_le2host(bs->bps); |
81 | rscnt = uint16_t_le2host(bs->rscnt); |
78 | rscnt = uint16_t_le2host(bs->rscnt); |
82 | 79 | ||
83 | if (firstc == FAT_CLST_RES0) { |
80 | if (firstc == FAT_CLST_RES0) { |
84 | /* No space allocated to the file. */ |
81 | /* No space allocated to the file. */ |
85 | if (ult) |
82 | if (lastc) |
86 | *ult = firstc; |
83 | *lastc = firstc; |
87 | return 0; |
84 | return 0; |
88 | } |
85 | } |
89 | 86 | ||
90 | /* At this point, the meaning of penult is not well-defined. */ |
- | |
91 | if (penult) |
- | |
92 | *penult = FAT_CLST_RES0; |
- | |
93 | - | ||
94 | while (clst < FAT_CLST_LAST1 && clusters < max_clusters) { |
87 | while (clst < FAT_CLST_LAST1 && clusters < max_clusters) { |
95 | unsigned fsec; /* sector offset relative to FAT1 */ |
88 | bn_t fsec; /* sector offset relative to FAT1 */ |
96 | unsigned fidx; /* FAT1 entry index */ |
89 | unsigned fidx; /* FAT1 entry index */ |
97 | 90 | ||
98 | assert(clst >= FAT_CLST_FIRST); |
91 | assert(clst >= FAT_CLST_FIRST); |
99 | if (penult) |
92 | if (lastc) |
100 | *penult = clst; /* remember the penultimate cluster */ |
93 | *lastc = clst; /* remember the last cluster number */ |
101 | fsec = (clst * sizeof(fat_cluster_t)) / bps; |
94 | fsec = (clst * sizeof(fat_cluster_t)) / bps; |
102 | fidx = clst % (bps / sizeof(fat_cluster_t)); |
95 | fidx = clst % (bps / sizeof(fat_cluster_t)); |
103 | /* read FAT1 */ |
96 | /* read FAT1 */ |
104 | b = block_get(dev_handle, rscnt + fsec); |
97 | b = block_get(dev_handle, rscnt + fsec); |
105 | clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]); |
98 | clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]); |
106 | assert(clst != FAT_CLST_BAD); |
99 | assert(clst != FAT_CLST_BAD); |
107 | block_put(b); |
100 | block_put(b); |
108 | clusters++; |
101 | clusters++; |
109 | } |
102 | } |
110 | 103 | ||
111 | if (ult) |
104 | if (lastc && clst < FAT_CLST_LAST1) |
112 | *ult = clst; |
105 | *lastc = clst; |
113 | 106 | ||
114 | return clusters; |
107 | return clusters; |
115 | } |
108 | } |
116 | 109 | ||
117 | /** Read block from file located on a FAT file system. |
110 | /** Read block from file located on a FAT file system. |
118 | * |
111 | * |
119 | * @param bs Buffer holding the boot sector of the file system. |
112 | * @param bs Buffer holding the boot sector of the file system. |
120 | * @param dev_handle Device handle of the file system. |
113 | * @param dev_handle Device handle of the file system. |
121 | * @param firstc First cluster used by the file. Can be zero if the file |
114 | * @param firstc First cluster used by the file. Can be zero if the file |
122 | * is empty. |
115 | * is empty. |
123 | * @param offset Offset in blocks. |
116 | * @param bn Block number. |
124 | * |
117 | * |
125 | * @return Block structure holding the requested block. |
118 | * @return Block structure holding the requested block. |
126 | */ |
119 | */ |
127 | block_t * |
120 | block_t * |
128 | _fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc, |
121 | _fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc, |
129 | off_t offset) |
122 | bn_t bn) |
130 | { |
123 | { |
131 | block_t *b; |
124 | block_t *b; |
132 | unsigned bps; |
125 | unsigned bps; |
133 | unsigned rscnt; /* block address of the first FAT */ |
126 | unsigned rscnt; /* block address of the first FAT */ |
134 | unsigned rde; |
127 | unsigned rde; |
135 | unsigned rds; /* root directory size */ |
128 | unsigned rds; /* root directory size */ |
136 | unsigned sf; |
129 | unsigned sf; |
137 | unsigned ssa; /* size of the system area */ |
130 | unsigned ssa; /* size of the system area */ |
138 | unsigned clusters, max_clusters; |
131 | unsigned clusters, max_clusters; |
139 | fat_cluster_t lastc, clst = firstc; |
132 | fat_cluster_t lastc; |
140 | 133 | ||
141 | bps = uint16_t_le2host(bs->bps); |
134 | bps = uint16_t_le2host(bs->bps); |
142 | rscnt = uint16_t_le2host(bs->rscnt); |
135 | rscnt = uint16_t_le2host(bs->rscnt); |
143 | rde = uint16_t_le2host(bs->root_ent_max); |
136 | rde = uint16_t_le2host(bs->root_ent_max); |
144 | sf = uint16_t_le2host(bs->sec_per_fat); |
137 | sf = uint16_t_le2host(bs->sec_per_fat); |
145 | 138 | ||
146 | rds = (sizeof(fat_dentry_t) * rde) / bps; |
139 | rds = (sizeof(fat_dentry_t) * rde) / bps; |
147 | rds += ((sizeof(fat_dentry_t) * rde) % bps != 0); |
140 | rds += ((sizeof(fat_dentry_t) * rde) % bps != 0); |
148 | ssa = rscnt + bs->fatcnt * sf + rds; |
141 | ssa = rscnt + bs->fatcnt * sf + rds; |
149 | 142 | ||
150 | if (firstc == FAT_CLST_ROOT) { |
143 | if (firstc == FAT_CLST_ROOT) { |
151 | /* root directory special case */ |
144 | /* root directory special case */ |
152 | assert(offset < rds); |
145 | assert(bn < rds); |
153 | b = block_get(dev_handle, rscnt + bs->fatcnt * sf + offset); |
146 | b = block_get(dev_handle, rscnt + bs->fatcnt * sf + bn); |
154 | return b; |
147 | return b; |
155 | } |
148 | } |
156 | 149 | ||
157 | max_clusters = offset / bs->spc; |
150 | max_clusters = bn / bs->spc; |
158 | clusters = fat_cluster_walk(bs, dev_handle, firstc, NULL, &lastc, |
151 | clusters = fat_cluster_walk(bs, dev_handle, firstc, &lastc, |
159 | max_clusters); |
152 | max_clusters); |
160 | assert(clusters == max_clusters); |
153 | assert(clusters == max_clusters); |
161 | 154 | ||
162 | b = block_get(dev_handle, ssa + (lastc - FAT_CLST_FIRST) * bs->spc + |
155 | b = block_get(dev_handle, ssa + (lastc - FAT_CLST_FIRST) * bs->spc + |
163 | offset % bs->spc); |
156 | bn % bs->spc); |
164 | 157 | ||
165 | return b; |
158 | return b; |
166 | } |
159 | } |
167 | 160 | ||
168 | - | ||
169 | /** Fill the gap between EOF and a new file position. |
161 | /** Fill the gap between EOF and a new file position. |
170 | * |
162 | * |
171 | * @param bs Buffer holding the boot sector for nodep. |
163 | * @param bs Buffer holding the boot sector for nodep. |
172 | * @param nodep FAT node with the gap. |
164 | * @param nodep FAT node with the gap. |
173 | * @param mcl First cluster in an independent cluster chain that will |
165 | * @param mcl First cluster in an independent cluster chain that will |
174 | * be later appended to the end of the node's own cluster |
166 | * be later appended to the end of the node's own cluster |
175 | * chain. If pos is still in the last allocated cluster, |
167 | * chain. If pos is still in the last allocated cluster, |
176 | * this argument is ignored. |
168 | * this argument is ignored. |
177 | * @param pos Position in the last node block. |
169 | * @param pos Position in the last node block. |
178 | */ |
170 | */ |
179 | void fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, off_t pos) |
171 | void fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, off_t pos) |
180 | { |
172 | { |
181 | uint16_t bps; |
173 | uint16_t bps; |
182 | unsigned spc; |
174 | unsigned spc; |
183 | block_t *b; |
175 | block_t *b; |
184 | off_t o, boundary; |
176 | off_t o, boundary; |
185 | 177 | ||
186 | bps = uint16_t_le2host(bs->bps); |
178 | bps = uint16_t_le2host(bs->bps); |
187 | spc = bs->spc; |
179 | spc = bs->spc; |
188 | 180 | ||
189 | boundary = ROUND_UP(nodep->size, bps * spc); |
181 | boundary = ROUND_UP(nodep->size, bps * spc); |
190 | 182 | ||
191 | /* zero out already allocated space */ |
183 | /* zero out already allocated space */ |
192 | for (o = nodep->size - 1; o < pos && o < boundary; |
184 | for (o = nodep->size - 1; o < pos && o < boundary; |
193 | o = ALIGN_DOWN(o + bps, bps)) { |
185 | o = ALIGN_DOWN(o + bps, bps)) { |
194 | b = fat_block_get(bs, nodep, o / bps); |
186 | b = fat_block_get(bs, nodep, o / bps); |
195 | memset(b->data + o % bps, 0, bps - o % bps); |
187 | memset(b->data + o % bps, 0, bps - o % bps); |
196 | b->dirty = true; /* need to sync node */ |
188 | b->dirty = true; /* need to sync node */ |
197 | block_put(b); |
189 | block_put(b); |
198 | } |
190 | } |
199 | 191 | ||
200 | if (o >= pos) |
192 | if (o >= pos) |
201 | return; |
193 | return; |
202 | 194 | ||
203 | /* zero out the initial part of the new cluster chain */ |
195 | /* zero out the initial part of the new cluster chain */ |
204 | for (o = boundary; o < pos; o += bps) { |
196 | for (o = boundary; o < pos; o += bps) { |
205 | b = _fat_block_get(bs, nodep->idx->dev_handle, mcl, |
197 | b = _fat_block_get(bs, nodep->idx->dev_handle, mcl, |
206 | (o - boundary) / bps); |
198 | (o - boundary) / bps); |
207 | memset(b->data, 0, min(bps, pos - o)); |
199 | memset(b->data, 0, min(bps, pos - o)); |
208 | b->dirty = true; /* need to sync node */ |
200 | b->dirty = true; /* need to sync node */ |
209 | block_put(b); |
201 | block_put(b); |
210 | } |
202 | } |
211 | } |
203 | } |
212 | 204 | ||
- | 205 | /** Get cluster from the first FAT. |
|
- | 206 | * |
|
- | 207 | * @param bs Buffer holding the boot sector for the file system. |
|
- | 208 | * @param dev_handle Device handle for the file system. |
|
- | 209 | * @param clst Cluster which to get. |
|
- | 210 | * |
|
- | 211 | * @return Value found in the cluster. |
|
- | 212 | */ |
|
- | 213 | fat_cluster_t |
|
- | 214 | fat_get_cluster(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t clst) |
|
- | 215 | { |
|
- | 216 | block_t *b; |
|
- | 217 | uint16_t bps; |
|
- | 218 | uint16_t rscnt; |
|
- | 219 | fat_cluster_t *cp, value; |
|
- | 220 | ||
- | 221 | bps = uint16_t_le2host(bs->bps); |
|
- | 222 | rscnt = uint16_t_le2host(bs->rscnt); |
|
- | 223 | ||
- | 224 | b = block_get(dev_handle, rscnt + (clst * sizeof(fat_cluster_t)) / bps); |
|
- | 225 | cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t)); |
|
- | 226 | value = uint16_t_le2host(*cp); |
|
- | 227 | block_put(b); |
|
- | 228 | ||
- | 229 | return value; |
|
- | 230 | } |
|
- | 231 | ||
213 | /** Mark cluster in one instance of FAT. |
232 | /** Set cluster in one instance of FAT. |
214 | * |
233 | * |
215 | * @param bs Buffer holding the boot sector for the file system. |
234 | * @param bs Buffer holding the boot sector for the file system. |
216 | * @param dev_handle Device handle for the file system. |
235 | * @param dev_handle Device handle for the file system. |
217 | * @param fatno Number of the FAT instance where to make the change. |
236 | * @param fatno Number of the FAT instance where to make the change. |
218 | * @param clst Cluster which is to be marked. |
237 | * @param clst Cluster which is to be set. |
219 | * @param value Value mark the cluster with. |
238 | * @param value Value to set the cluster with. |
220 | */ |
239 | */ |
221 | void |
240 | void |
222 | fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno, |
241 | fat_set_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno, |
223 | fat_cluster_t clst, fat_cluster_t value) |
242 | fat_cluster_t clst, fat_cluster_t value) |
224 | { |
243 | { |
225 | block_t *b; |
244 | block_t *b; |
226 | uint16_t bps; |
245 | uint16_t bps; |
227 | uint16_t rscnt; |
246 | uint16_t rscnt; |
228 | uint16_t sf; |
247 | uint16_t sf; |
229 | fat_cluster_t *cp; |
248 | fat_cluster_t *cp; |
230 | 249 | ||
231 | bps = uint16_t_le2host(bs->bps); |
250 | bps = uint16_t_le2host(bs->bps); |
232 | rscnt = uint16_t_le2host(bs->rscnt); |
251 | rscnt = uint16_t_le2host(bs->rscnt); |
233 | sf = uint16_t_le2host(bs->sec_per_fat); |
252 | sf = uint16_t_le2host(bs->sec_per_fat); |
234 | 253 | ||
235 | assert(fatno < bs->fatcnt); |
254 | assert(fatno < bs->fatcnt); |
236 | b = block_get(dev_handle, rscnt + sf * fatno + |
255 | b = block_get(dev_handle, rscnt + sf * fatno + |
237 | (clst * sizeof(fat_cluster_t)) / bps); |
256 | (clst * sizeof(fat_cluster_t)) / bps); |
238 | cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t)); |
257 | cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t)); |
239 | *cp = host2uint16_t_le(value); |
258 | *cp = host2uint16_t_le(value); |
240 | b->dirty = true; /* need to sync block */ |
259 | b->dirty = true; /* need to sync block */ |
241 | block_put(b); |
260 | block_put(b); |
242 | } |
261 | } |
243 | 262 | ||
244 | /** Replay the allocatoin of clusters in all shadow instances of FAT. |
263 | /** Replay the allocatoin of clusters in all shadow instances of FAT. |
245 | * |
264 | * |
246 | * @param bs Buffer holding the boot sector of the file system. |
265 | * @param bs Buffer holding the boot sector of the file system. |
247 | * @param dev_handle Device handle of the file system. |
266 | * @param dev_handle Device handle of the file system. |
248 | * @param lifo Chain of allocated clusters. |
267 | * @param lifo Chain of allocated clusters. |
249 | * @param nclsts Number of clusters in the lifo chain. |
268 | * @param nclsts Number of clusters in the lifo chain. |
250 | */ |
269 | */ |
251 | void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle, |
270 | void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle, |
252 | fat_cluster_t *lifo, unsigned nclsts) |
271 | fat_cluster_t *lifo, unsigned nclsts) |
253 | { |
272 | { |
254 | uint8_t fatno; |
273 | uint8_t fatno; |
255 | unsigned c; |
274 | unsigned c; |
256 | 275 | ||
257 | for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) { |
276 | for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) { |
258 | for (c = 0; c < nclsts; c++) { |
277 | for (c = 0; c < nclsts; c++) { |
259 | fat_mark_cluster(bs, dev_handle, fatno, lifo[c], |
278 | fat_set_cluster(bs, dev_handle, fatno, lifo[c], |
260 | c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]); |
279 | c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]); |
261 | } |
280 | } |
262 | } |
281 | } |
263 | } |
282 | } |
264 | 283 | ||
265 | /** Allocate clusters in FAT1. |
284 | /** Allocate clusters in FAT1. |
266 | * |
285 | * |
267 | * This function will attempt to allocate the requested number of clusters in |
286 | * This function will attempt to allocate the requested number of clusters in |
268 | * the first FAT instance. The FAT will be altered so that the allocated |
287 | * the first FAT instance. The FAT will be altered so that the allocated |
269 | * clusters form an independent chain (i.e. a chain which does not belong to any |
288 | * clusters form an independent chain (i.e. a chain which does not belong to any |
270 | * file yet). |
289 | * file yet). |
271 | * |
290 | * |
272 | * @param bs Buffer holding the boot sector of the file system. |
291 | * @param bs Buffer holding the boot sector of the file system. |
273 | * @param dev_handle Device handle of the file system. |
292 | * @param dev_handle Device handle of the file system. |
274 | * @param nclsts Number of clusters to allocate. |
293 | * @param nclsts Number of clusters to allocate. |
275 | * @param mcl Output parameter where the first cluster in the chain |
294 | * @param mcl Output parameter where the first cluster in the chain |
276 | * will be returned. |
295 | * will be returned. |
277 | * @param lcl Output parameter where the last cluster in the chain |
296 | * @param lcl Output parameter where the last cluster in the chain |
278 | * will be returned. |
297 | * will be returned. |
279 | * |
298 | * |
280 | * @return EOK on success, a negative error code otherwise. |
299 | * @return EOK on success, a negative error code otherwise. |
281 | */ |
300 | */ |
282 | int |
301 | int |
283 | fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts, |
302 | fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts, |
284 | fat_cluster_t *mcl, fat_cluster_t *lcl) |
303 | fat_cluster_t *mcl, fat_cluster_t *lcl) |
285 | { |
304 | { |
286 | uint16_t bps; |
305 | uint16_t bps; |
287 | uint16_t rscnt; |
306 | uint16_t rscnt; |
288 | uint16_t sf; |
307 | uint16_t sf; |
289 | block_t *blk; |
308 | block_t *blk; |
290 | fat_cluster_t *lifo; /* stack for storing free cluster numbers */ |
309 | fat_cluster_t *lifo; /* stack for storing free cluster numbers */ |
291 | unsigned found = 0; /* top of the free cluster number stack */ |
310 | unsigned found = 0; /* top of the free cluster number stack */ |
292 | unsigned b, c, cl; |
311 | unsigned b, c, cl; |
293 | 312 | ||
294 | lifo = (fat_cluster_t *) malloc(nclsts * sizeof(fat_cluster_t)); |
313 | lifo = (fat_cluster_t *) malloc(nclsts * sizeof(fat_cluster_t)); |
295 | if (lifo) |
314 | if (lifo) |
296 | return ENOMEM; |
315 | return ENOMEM; |
297 | 316 | ||
298 | bps = uint16_t_le2host(bs->bps); |
317 | bps = uint16_t_le2host(bs->bps); |
299 | rscnt = uint16_t_le2host(bs->rscnt); |
318 | rscnt = uint16_t_le2host(bs->rscnt); |
300 | sf = uint16_t_le2host(bs->sec_per_fat); |
319 | sf = uint16_t_le2host(bs->sec_per_fat); |
301 | 320 | ||
302 | /* |
321 | /* |
303 | * Search FAT1 for unused clusters. |
322 | * Search FAT1 for unused clusters. |
304 | */ |
323 | */ |
305 | futex_down(&fat_alloc_lock); |
324 | futex_down(&fat_alloc_lock); |
306 | for (b = 0, cl = 0; b < sf; blk++) { |
325 | for (b = 0, cl = 0; b < sf; blk++) { |
307 | blk = block_get(dev_handle, rscnt + b); |
326 | blk = block_get(dev_handle, rscnt + b); |
308 | for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) { |
327 | for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) { |
309 | fat_cluster_t *clst = (fat_cluster_t *)blk->data + c; |
328 | fat_cluster_t *clst = (fat_cluster_t *)blk->data + c; |
310 | if (uint16_t_le2host(*clst) == FAT_CLST_RES0) { |
329 | if (uint16_t_le2host(*clst) == FAT_CLST_RES0) { |
311 | /* |
330 | /* |
312 | * The cluster is free. Put it into our stack |
331 | * The cluster is free. Put it into our stack |
313 | * of found clusters and mark it as non-free. |
332 | * of found clusters and mark it as non-free. |
314 | */ |
333 | */ |
315 | lifo[found] = cl; |
334 | lifo[found] = cl; |
316 | *clst = (found == 0) ? |
335 | *clst = (found == 0) ? |
317 | host2uint16_t_le(FAT_CLST_LAST1) : |
336 | host2uint16_t_le(FAT_CLST_LAST1) : |
318 | host2uint16_t_le(lifo[found - 1]); |
337 | host2uint16_t_le(lifo[found - 1]); |
319 | blk->dirty = true; /* need to sync block */ |
338 | blk->dirty = true; /* need to sync block */ |
320 | if (++found == nclsts) { |
339 | if (++found == nclsts) { |
321 | /* we are almost done */ |
340 | /* we are almost done */ |
322 | block_put(blk); |
341 | block_put(blk); |
323 | /* update the shadow copies of FAT */ |
342 | /* update the shadow copies of FAT */ |
324 | fat_alloc_shadow_clusters(bs, |
343 | fat_alloc_shadow_clusters(bs, |
325 | dev_handle, lifo, nclsts); |
344 | dev_handle, lifo, nclsts); |
326 | *mcl = lifo[found - 1]; |
345 | *mcl = lifo[found - 1]; |
327 | *lcl = lifo[0]; |
346 | *lcl = lifo[0]; |
328 | free(lifo); |
347 | free(lifo); |
329 | futex_up(&fat_alloc_lock); |
348 | futex_up(&fat_alloc_lock); |
330 | return EOK; |
349 | return EOK; |
331 | } |
350 | } |
332 | } |
351 | } |
333 | } |
352 | } |
334 | block_put(blk); |
353 | block_put(blk); |
335 | } |
354 | } |
336 | futex_up(&fat_alloc_lock); |
355 | futex_up(&fat_alloc_lock); |
337 | 356 | ||
338 | /* |
357 | /* |
339 | * We could not find enough clusters. Now we need to free the clusters |
358 | * We could not find enough clusters. Now we need to free the clusters |
340 | * we have allocated so far. |
359 | * we have allocated so far. |
341 | */ |
360 | */ |
342 | while (found--) { |
361 | while (found--) { |
343 | fat_mark_cluster(bs, dev_handle, FAT1, lifo[found], |
362 | fat_set_cluster(bs, dev_handle, FAT1, lifo[found], |
344 | FAT_CLST_RES0); |
363 | FAT_CLST_RES0); |
345 | } |
364 | } |
346 | 365 | ||
347 | free(lifo); |
366 | free(lifo); |
348 | return ENOSPC; |
367 | return ENOSPC; |
349 | } |
368 | } |
350 | 369 | ||
- | 370 | /** Free clusters forming a cluster chain in all copies of FAT. |
|
- | 371 | * |
|
- | 372 | * @param bs Buffer hodling the boot sector of the file system. |
|
- | 373 | * @param dev_handle Device handle of the file system. |
|
- | 374 | * @param firstc First cluster in the chain which is to be freed. |
|
- | 375 | */ |
|
- | 376 | void |
|
- | 377 | fat_free_clusters(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc) |
|
- | 378 | { |
|
- | 379 | unsigned fatno; |
|
- | 380 | fat_cluster_t nextc; |
|
- | 381 | ||
- | 382 | /* Mark all clusters in the chain as free in all copies of FAT. */ |
|
- | 383 | while (firstc < FAT_CLST_LAST1) { |
|
- | 384 | nextc = fat_get_cluster(bs, dev_handle, firstc); |
|
- | 385 | assert(nextc >= FAT_CLST_FIRST && nextc < FAT_CLST_BAD); |
|
- | 386 | for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
|
- | 387 | fat_set_cluster(bs, dev_handle, fatno, firstc, |
|
- | 388 | FAT_CLST_RES0); |
|
- | 389 | firstc = nextc; |
|
- | 390 | } |
|
- | 391 | } |
|
- | 392 | ||
351 | /** Append a cluster chain to the last file cluster in all FATs. |
393 | /** Append a cluster chain to the last file cluster in all FATs. |
352 | * |
394 | * |
353 | * @param bs Buffer holding boot sector of the file system. |
395 | * @param bs Buffer holding the boot sector of the file system. |
354 | * @param nodep Node representing the file. |
396 | * @param nodep Node representing the file. |
355 | * @param mcl First cluster of the cluster chain to append. |
397 | * @param mcl First cluster of the cluster chain to append. |
356 | */ |
398 | */ |
357 | void fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl) |
399 | void fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl) |
358 | { |
400 | { |
359 | dev_handle_t dev_handle = nodep->idx->dev_handle; |
401 | dev_handle_t dev_handle = nodep->idx->dev_handle; |
360 | fat_cluster_t lcl; |
402 | fat_cluster_t lcl; |
361 | uint8_t fatno; |
403 | uint8_t fatno; |
362 | 404 | ||
363 | if (fat_cluster_walk(bs, nodep->idx->dev_handle, nodep->firstc, &lcl, |
405 | if (fat_cluster_walk(bs, dev_handle, nodep->firstc, &lcl, |
364 | NULL, (uint16_t) -1) == 0) { |
406 | (uint16_t) -1) == 0) { |
365 | /* No clusters allocated to the node yet. */ |
407 | /* No clusters allocated to the node yet. */ |
366 | nodep->firstc = host2uint16_t_le(mcl); |
408 | nodep->firstc = host2uint16_t_le(mcl); |
367 | nodep->dirty = true; /* need to sync node */ |
409 | nodep->dirty = true; /* need to sync node */ |
368 | return; |
410 | return; |
369 | } |
411 | } |
370 | 412 | ||
371 | for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
413 | for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
372 | fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl); |
414 | fat_set_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl); |
- | 415 | } |
|
- | 416 | ||
- | 417 | /** Chop off node clusters in all copies of FAT. |
|
- | 418 | * |
|
- | 419 | * @param bs Buffer holding the boot sector of the file system. |
|
- | 420 | * @param nodep FAT node where the chopping will take place. |
|
- | 421 | * @param lastc Last cluster which will remain in the node. If this |
|
- | 422 | * argument is FAT_CLST_RES0, then all clusters will |
|
- | 423 | * be chopped off. |
|
- | 424 | */ |
|
- | 425 | void fat_chop_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t lastc) |
|
- | 426 | { |
|
- | 427 | dev_handle_t dev_handle = nodep->idx->dev_handle; |
|
- | 428 | if (lastc == FAT_CLST_RES0) { |
|
- | 429 | /* The node will have zero size and no clusters allocated. */ |
|
- | 430 | fat_free_clusters(bs, dev_handle, nodep->firstc); |
|
- | 431 | nodep->firstc = FAT_CLST_RES0; |
|
- | 432 | nodep->dirty = true; /* need to sync node */ |
|
- | 433 | } else { |
|
- | 434 | fat_cluster_t nextc; |
|
- | 435 | unsigned fatno; |
|
- | 436 | ||
- | 437 | nextc = fat_get_cluster(bs, dev_handle, lastc); |
|
- | 438 | ||
- | 439 | /* Terminate the cluster chain in all copies of FAT. */ |
|
- | 440 | for (fatno = FAT1; fatno < bs->fatcnt; fatno++) |
|
- | 441 | fat_set_cluster(bs, dev_handle, fatno, lastc, FAT_CLST_LAST1); |
|
- | 442 | ||
- | 443 | /* Free all following clusters. */ |
|
- | 444 | fat_free_clusters(bs, dev_handle, nextc); |
|
- | 445 | } |
|
373 | } |
446 | } |
374 | 447 | ||
375 | /** |
448 | /** |
376 | * @} |
449 | * @} |
377 | */ |
450 | */ |
378 | 451 |