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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
/** Read block from file located on a FAT file system.
57
/** Walk the cluster chain.
58
 *
58
 *
59
 * @param bs        Buffer holding the boot sector of the file system.
59
 * @param bs        Buffer holding the boot sector for the file.
60
 * @param dev_handle    Device handle of the file system.
60
 * @param dev_handle    Device handle of the device with the file.
61
 * @param firstc    First cluster used by the file. Can be zero if the file
61
 * @param firstc    First cluster to start the walk with.
-
 
62
 * @param penult    If non-NULL, output argument hodling the
-
 
63
 *          the penultimate cluster visited.
-
 
64
 * @param ult       If non-NULL, output argument holding the
62
 *          is empty.
65
 *          ultimate cluster visited.
63
 * @param offset    Offset in blocks.
66
 * @param max_clusters  Maximum number of clusters to visit.   
64
 *
67
 *
65
 * @return      Block structure holding the requested block.
68
 * @return      Number of clusters seen during the walk.
66
 */
69
 */
67
block_t *
70
uint16_t
68
_fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
71
fat_cluster_walk(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
69
    off_t offset)
72
    fat_cluster_t *penult, fat_cluster_t *ult, uint16_t max_clusters)
70
{
73
{
71
    block_t *b;
74
    block_t *b;
72
    unsigned bps;
75
    unsigned bps;
73
    unsigned spc;
-
 
74
    unsigned rscnt;     /* block address of the first FAT */
76
    unsigned rscnt;     /* block address of the first FAT */
75
    unsigned fatcnt;
-
 
76
    unsigned rde;
-
 
77
    unsigned rds;       /* root directory size */
-
 
78
    unsigned sf;
-
 
79
    unsigned ssa;       /* size of the system area */
-
 
80
    unsigned clusters;
77
    uint16_t clusters = 0;
81
    fat_cluster_t clst = firstc;
78
    fat_cluster_t clst = firstc;
82
    unsigned i;
-
 
83
 
79
 
84
    bps = uint16_t_le2host(bs->bps);
80
    bps = uint16_t_le2host(bs->bps);
85
    spc = bs->spc;
-
 
86
    rscnt = uint16_t_le2host(bs->rscnt);
81
    rscnt = uint16_t_le2host(bs->rscnt);
87
    fatcnt = bs->fatcnt;
-
 
88
    rde = uint16_t_le2host(bs->root_ent_max);
-
 
89
    sf = uint16_t_le2host(bs->sec_per_fat);
-
 
90
 
82
 
91
    rds = (sizeof(fat_dentry_t) * rde) / bps;
-
 
92
    rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
-
 
93
    ssa = rscnt + fatcnt * sf + rds;
-
 
94
 
-
 
95
    if (firstc == FAT_CLST_ROOT) {
83
    if (firstc == FAT_CLST_RES0) {
96
        /* root directory special case */
84
        /* No space allocated to the file. */
97
        assert(offset < rds);
85
        if (ult)
98
        b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
86
            *ult = firstc;
99
        return b;
87
        return 0;
100
    }
88
    }
101
 
89
 
-
 
90
    /* At this point, the meaning of penult is not well-defined. */
-
 
91
    if (penult)
102
    clusters = offset / spc;
92
        *penult = FAT_CLST_RES0;
-
 
93
 
103
    for (i = 0; i < clusters; i++) {
94
    while (clst < FAT_CLST_LAST1 && clusters < max_clusters) {
104
        unsigned fsec;  /* sector offset relative to FAT1 */
95
        unsigned fsec;  /* sector offset relative to FAT1 */
105
        unsigned fidx;  /* FAT1 entry index */
96
        unsigned fidx;  /* FAT1 entry index */
106
 
97
 
107
        assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
98
        assert(clst >= FAT_CLST_FIRST);
-
 
99
        if (penult)
-
 
100
            *penult = clst; /* remember the penultimate cluster */
108
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
101
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
109
        fidx = clst % (bps / sizeof(fat_cluster_t));
102
        fidx = clst % (bps / sizeof(fat_cluster_t));
110
        /* read FAT1 */
103
        /* read FAT1 */
111
        b = block_get(dev_handle, rscnt + fsec, bps);
104
        b = block_get(dev_handle, rscnt + fsec);
112
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
105
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
113
        assert(clst != FAT_CLST_BAD);
106
        assert(clst != FAT_CLST_BAD);
114
        assert(clst < FAT_CLST_LAST1);
-
 
115
        block_put(b);
107
        block_put(b);
-
 
108
        clusters++;
116
    }
109
    }
117
 
110
 
118
    b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
111
    if (ult)
119
        offset % spc, bps);
112
        *ult = clst;
120
 
113
 
121
    return b;
114
    return clusters;
122
}
115
}
123
 
116
 
124
/** Return number of blocks allocated to a file.
117
/** Read block from file located on a FAT file system.
125
 *
118
 *
126
 * @param bs        Buffer holding the boot sector for the file.
119
 * @param bs        Buffer holding the boot sector of the file system.
127
 * @param dev_handle    Device handle of the device with the file.
120
 * @param dev_handle    Device handle of the file system.
128
 * @param firstc    First cluster of the file.
121
 * @param firstc    First cluster used by the file. Can be zero if the file
129
 * @param lastc     If non-NULL, output argument holding the
-
 
130
 *          last cluster.
122
 *          is empty.
-
 
123
 * @param offset    Offset in blocks.
131
 *
124
 *
132
 * @return      Number of blocks allocated to the file.
125
 * @return      Block structure holding the requested block.
133
 */
126
 */
134
uint16_t
127
block_t *
135
_fat_blcks_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
128
_fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
136
    fat_cluster_t *lastc)
129
    off_t offset)
137
{
130
{
138
    block_t *b;
131
    block_t *b;
139
    unsigned bps;
132
    unsigned bps;
140
    unsigned spc;
-
 
141
    unsigned rscnt;     /* block address of the first FAT */
133
    unsigned rscnt;     /* block address of the first FAT */
-
 
134
    unsigned rde;
-
 
135
    unsigned rds;       /* root directory size */
-
 
136
    unsigned sf;
-
 
137
    unsigned ssa;       /* size of the system area */
142
    unsigned clusters = 0;
138
    unsigned clusters, max_clusters;
143
    fat_cluster_t clst = firstc;
139
    fat_cluster_t lastc, clst = firstc;
144
 
140
 
145
    bps = uint16_t_le2host(bs->bps);
141
    bps = uint16_t_le2host(bs->bps);
146
    spc = bs->spc;
-
 
147
    rscnt = uint16_t_le2host(bs->rscnt);
142
    rscnt = uint16_t_le2host(bs->rscnt);
-
 
143
    rde = uint16_t_le2host(bs->root_ent_max);
-
 
144
    sf = uint16_t_le2host(bs->sec_per_fat);
148
 
145
 
-
 
146
    rds = (sizeof(fat_dentry_t) * rde) / bps;
-
 
147
    rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
-
 
148
    ssa = rscnt + bs->fatcnt * sf + rds;
-
 
149
 
149
    if (firstc == FAT_CLST_RES0) {
150
    if (firstc == FAT_CLST_ROOT) {
150
        /* No space allocated to the file. */
151
        /* root directory special case */
151
        if (lastc)
152
        assert(offset < rds);
152
            *lastc = firstc;
153
        b = block_get(dev_handle, rscnt + bs->fatcnt * sf + offset);
153
        return 0;
154
        return b;
154
    }
155
    }
155
 
156
 
156
    while (clst < FAT_CLST_LAST1) {
157
    max_clusters = offset / bs->spc;
157
        unsigned fsec;  /* sector offset relative to FAT1 */
158
    clusters = fat_cluster_walk(bs, dev_handle, firstc, NULL, &lastc,
-
 
159
        max_clusters);
158
        unsigned fidx;  /* FAT1 entry index */
160
    assert(clusters == max_clusters);
159
 
161
 
160
        assert(clst >= FAT_CLST_FIRST);
-
 
161
        if (lastc)
-
 
162
            *lastc = clst;      /* remember the last cluster */
-
 
163
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
-
 
164
        fidx = clst % (bps / sizeof(fat_cluster_t));
-
 
165
        /* read FAT1 */
-
 
166
        b = block_get(dev_handle, rscnt + fsec, bps);
162
    b = block_get(dev_handle, ssa + (lastc - FAT_CLST_FIRST) * bs->spc +
167
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
-
 
168
        assert(clst != FAT_CLST_BAD);
-
 
169
        block_put(b);
163
        offset % bs->spc);
170
        clusters++;
-
 
171
    }
-
 
172
 
164
 
173
    if (lastc)
-
 
174
        *lastc = clst;
-
 
175
    return clusters * spc;
165
    return b;
176
}
166
}
177
 
167
 
-
 
168
 
178
/** Fill the gap between EOF and a new file position.
169
/** Fill the gap between EOF and a new file position.
179
 *
170
 *
180
 * @param bs        Buffer holding the boot sector for nodep.
171
 * @param bs        Buffer holding the boot sector for nodep.
181
 * @param nodep     FAT node with the gap.
172
 * @param nodep     FAT node with the gap.
182
 * @param mcl       First cluster in an independent cluster chain that will
173
 * @param mcl       First cluster in an independent cluster chain that will
183
 *          be later appended to the end of the node's own cluster
174
 *          be later appended to the end of the node's own cluster
184
 *          chain. If pos is still in the last allocated cluster,
175
 *          chain. If pos is still in the last allocated cluster,
185
 *          this argument is ignored.
176
 *          this argument is ignored.
186
 * @param pos       Position in the last node block.
177
 * @param pos       Position in the last node block.
187
 */
178
 */
188
void fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, off_t pos)
179
void fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, off_t pos)
189
{
180
{
190
    uint16_t bps;
181
    uint16_t bps;
191
    unsigned spc;
182
    unsigned spc;
192
    block_t *b;
183
    block_t *b;
193
    off_t o, boundary;
184
    off_t o, boundary;
194
 
185
 
195
    bps = uint16_t_le2host(bs->bps);
186
    bps = uint16_t_le2host(bs->bps);
196
    spc = bs->spc;
187
    spc = bs->spc;
197
   
188
   
198
    boundary = ROUND_UP(nodep->size, bps * spc);
189
    boundary = ROUND_UP(nodep->size, bps * spc);
199
 
190
 
200
    /* zero out already allocated space */
191
    /* zero out already allocated space */
201
    for (o = nodep->size - 1; o < pos && o < boundary;
192
    for (o = nodep->size - 1; o < pos && o < boundary;
202
        o = ALIGN_DOWN(o + bps, bps)) {
193
        o = ALIGN_DOWN(o + bps, bps)) {
203
        b = fat_block_get(bs, nodep, o / bps);
194
        b = fat_block_get(bs, nodep, o / bps);
204
        memset(b->data + o % bps, 0, bps - o % bps);
195
        memset(b->data + o % bps, 0, bps - o % bps);
205
        b->dirty = true;        /* need to sync node */
196
        b->dirty = true;        /* need to sync node */
206
        block_put(b);
197
        block_put(b);
207
    }
198
    }
208
   
199
   
209
    if (o >= pos)
200
    if (o >= pos)
210
        return;
201
        return;
211
   
202
   
212
    /* zero out the initial part of the new cluster chain */
203
    /* zero out the initial part of the new cluster chain */
213
    for (o = boundary; o < pos; o += bps) {
204
    for (o = boundary; o < pos; o += bps) {
214
        b = _fat_block_get(bs, nodep->idx->dev_handle, mcl,
205
        b = _fat_block_get(bs, nodep->idx->dev_handle, mcl,
215
            (o - boundary) / bps);
206
            (o - boundary) / bps);
216
        memset(b->data, 0, min(bps, pos - o));
207
        memset(b->data, 0, min(bps, pos - o));
217
        b->dirty = true;        /* need to sync node */
208
        b->dirty = true;        /* need to sync node */
218
        block_put(b);
209
        block_put(b);
219
    }
210
    }
220
}
211
}
221
 
212
 
222
/** Mark cluster in one instance of FAT.
213
/** Mark cluster in one instance of FAT.
223
 *
214
 *
224
 * @param bs        Buffer holding the boot sector for the file system.
215
 * @param bs        Buffer holding the boot sector for the file system.
225
 * @param dev_handle    Device handle for the file system.
216
 * @param dev_handle    Device handle for the file system.
226
 * @param fatno     Number of the FAT instance where to make the change.
217
 * @param fatno     Number of the FAT instance where to make the change.
227
 * @param clst      Cluster which is to be marked.
218
 * @param clst      Cluster which is to be marked.
228
 * @param value     Value mark the cluster with.
219
 * @param value     Value mark the cluster with.
229
 */
220
 */
230
void
221
void
231
fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
222
fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
232
    fat_cluster_t clst, fat_cluster_t value)
223
    fat_cluster_t clst, fat_cluster_t value)
233
{
224
{
234
    block_t *b;
225
    block_t *b;
235
    uint16_t bps;
226
    uint16_t bps;
236
    uint16_t rscnt;
227
    uint16_t rscnt;
237
    uint16_t sf;
228
    uint16_t sf;
238
    fat_cluster_t *cp;
229
    fat_cluster_t *cp;
239
 
230
 
240
    bps = uint16_t_le2host(bs->bps);
231
    bps = uint16_t_le2host(bs->bps);
241
    rscnt = uint16_t_le2host(bs->rscnt);
232
    rscnt = uint16_t_le2host(bs->rscnt);
242
    sf = uint16_t_le2host(bs->sec_per_fat);
233
    sf = uint16_t_le2host(bs->sec_per_fat);
243
 
234
 
244
    assert(fatno < bs->fatcnt);
235
    assert(fatno < bs->fatcnt);
245
    b = block_get(dev_handle, rscnt + sf * fatno +
236
    b = block_get(dev_handle, rscnt + sf * fatno +
246
        (clst * sizeof(fat_cluster_t)) / bps, bps);
237
        (clst * sizeof(fat_cluster_t)) / bps);
247
    cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));
238
    cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));
248
    *cp = host2uint16_t_le(value);
239
    *cp = host2uint16_t_le(value);
249
    b->dirty = true;        /* need to sync block */
240
    b->dirty = true;        /* need to sync block */
250
    block_put(b);
241
    block_put(b);
251
}
242
}
252
 
243
 
253
/** Replay the allocatoin of clusters in all shadow instances of FAT.
244
/** Replay the allocatoin of clusters in all shadow instances of FAT.
254
 *
245
 *
255
 * @param bs        Buffer holding the boot sector of the file system.
246
 * @param bs        Buffer holding the boot sector of the file system.
256
 * @param dev_handle    Device handle of the file system.
247
 * @param dev_handle    Device handle of the file system.
257
 * @param lifo      Chain of allocated clusters.
248
 * @param lifo      Chain of allocated clusters.
258
 * @param nclsts    Number of clusters in the lifo chain.
249
 * @param nclsts    Number of clusters in the lifo chain.
259
 */
250
 */
260
void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,
251
void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,
261
    fat_cluster_t *lifo, unsigned nclsts)
252
    fat_cluster_t *lifo, unsigned nclsts)
262
{
253
{
263
    uint8_t fatno;
254
    uint8_t fatno;
264
    unsigned c;
255
    unsigned c;
265
 
256
 
266
    for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) {
257
    for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) {
267
        for (c = 0; c < nclsts; c++) {
258
        for (c = 0; c < nclsts; c++) {
268
            fat_mark_cluster(bs, dev_handle, fatno, lifo[c],
259
            fat_mark_cluster(bs, dev_handle, fatno, lifo[c],
269
                c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]);
260
                c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]);
270
        }
261
        }
271
    }
262
    }
272
}
263
}
273
 
264
 
274
/** Allocate clusters in FAT1.
265
/** Allocate clusters in FAT1.
275
 *
266
 *
276
 * This function will attempt to allocate the requested number of clusters in
267
 * This function will attempt to allocate the requested number of clusters in
277
 * the first FAT instance.  The FAT will be altered so that the allocated
268
 * the first FAT instance.  The FAT will be altered so that the allocated
278
 * clusters form an independent chain (i.e. a chain which does not belong to any
269
 * clusters form an independent chain (i.e. a chain which does not belong to any
279
 * file yet).
270
 * file yet).
280
 *
271
 *
281
 * @param bs        Buffer holding the boot sector of the file system.
272
 * @param bs        Buffer holding the boot sector of the file system.
282
 * @param dev_handle    Device handle of the file system.
273
 * @param dev_handle    Device handle of the file system.
283
 * @param nclsts    Number of clusters to allocate.
274
 * @param nclsts    Number of clusters to allocate.
284
 * @param mcl       Output parameter where the first cluster in the chain
275
 * @param mcl       Output parameter where the first cluster in the chain
285
 *          will be returned.
276
 *          will be returned.
286
 * @param lcl       Output parameter where the last cluster in the chain
277
 * @param lcl       Output parameter where the last cluster in the chain
287
 *          will be returned.
278
 *          will be returned.
288
 *
279
 *
289
 * @return      EOK on success, a negative error code otherwise.
280
 * @return      EOK on success, a negative error code otherwise.
290
 */
281
 */
291
int
282
int
292
fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,
283
fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,
293
    fat_cluster_t *mcl, fat_cluster_t *lcl)
284
    fat_cluster_t *mcl, fat_cluster_t *lcl)
294
{
285
{
295
    uint16_t bps;
286
    uint16_t bps;
296
    uint16_t rscnt;
287
    uint16_t rscnt;
297
    uint16_t sf;
288
    uint16_t sf;
298
    block_t *blk;
289
    block_t *blk;
299
    fat_cluster_t *lifo;    /* stack for storing free cluster numbers */
290
    fat_cluster_t *lifo;    /* stack for storing free cluster numbers */
300
    unsigned found = 0; /* top of the free cluster number stack */
291
    unsigned found = 0; /* top of the free cluster number stack */
301
    unsigned b, c, cl;
292
    unsigned b, c, cl;
302
 
293
 
303
    lifo = (fat_cluster_t *) malloc(nclsts * sizeof(fat_cluster_t));
294
    lifo = (fat_cluster_t *) malloc(nclsts * sizeof(fat_cluster_t));
304
    if (lifo)
295
    if (lifo)
305
        return ENOMEM;
296
        return ENOMEM;
306
   
297
   
307
    bps = uint16_t_le2host(bs->bps);
298
    bps = uint16_t_le2host(bs->bps);
308
    rscnt = uint16_t_le2host(bs->rscnt);
299
    rscnt = uint16_t_le2host(bs->rscnt);
309
    sf = uint16_t_le2host(bs->sec_per_fat);
300
    sf = uint16_t_le2host(bs->sec_per_fat);
310
   
301
   
311
    /*
302
    /*
312
     * Search FAT1 for unused clusters.
303
     * Search FAT1 for unused clusters.
313
     */
304
     */
314
    futex_down(&fat_alloc_lock);
305
    futex_down(&fat_alloc_lock);
315
    for (b = 0, cl = 0; b < sf; blk++) {
306
    for (b = 0, cl = 0; b < sf; blk++) {
316
        blk = block_get(dev_handle, rscnt + b, bps);
307
        blk = block_get(dev_handle, rscnt + b);
317
        for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {
308
        for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {
318
            fat_cluster_t *clst = (fat_cluster_t *)blk->data + c;
309
            fat_cluster_t *clst = (fat_cluster_t *)blk->data + c;
319
            if (uint16_t_le2host(*clst) == FAT_CLST_RES0) {
310
            if (uint16_t_le2host(*clst) == FAT_CLST_RES0) {
320
                /*
311
                /*
321
                 * The cluster is free. Put it into our stack
312
                 * The cluster is free. Put it into our stack
322
                 * of found clusters and mark it as non-free.
313
                 * of found clusters and mark it as non-free.
323
                 */
314
                 */
324
                lifo[found] = cl;
315
                lifo[found] = cl;
325
                *clst = (found == 0) ?
316
                *clst = (found == 0) ?
326
                    host2uint16_t_le(FAT_CLST_LAST1) :
317
                    host2uint16_t_le(FAT_CLST_LAST1) :
327
                    host2uint16_t_le(lifo[found - 1]);
318
                    host2uint16_t_le(lifo[found - 1]);
328
                blk->dirty = true;  /* need to sync block */
319
                blk->dirty = true;  /* need to sync block */
329
                if (++found == nclsts) {
320
                if (++found == nclsts) {
330
                    /* we are almost done */
321
                    /* we are almost done */
331
                    block_put(blk);
322
                    block_put(blk);
332
                    /* update the shadow copies of FAT */
323
                    /* update the shadow copies of FAT */
333
                    fat_alloc_shadow_clusters(bs,
324
                    fat_alloc_shadow_clusters(bs,
334
                        dev_handle, lifo, nclsts);
325
                        dev_handle, lifo, nclsts);
335
                    *mcl = lifo[found - 1];
326
                    *mcl = lifo[found - 1];
336
                    *lcl = lifo[0];
327
                    *lcl = lifo[0];
337
                    free(lifo);
328
                    free(lifo);
338
                    futex_up(&fat_alloc_lock);
329
                    futex_up(&fat_alloc_lock);
339
                    return EOK;
330
                    return EOK;
340
                }
331
                }
341
            }
332
            }
342
        }
333
        }
343
        block_put(blk);
334
        block_put(blk);
344
    }
335
    }
345
    futex_up(&fat_alloc_lock);
336
    futex_up(&fat_alloc_lock);
346
 
337
 
347
    /*
338
    /*
348
     * We could not find enough clusters. Now we need to free the clusters
339
     * We could not find enough clusters. Now we need to free the clusters
349
     * we have allocated so far.
340
     * we have allocated so far.
350
     */
341
     */
351
    while (found--) {
342
    while (found--) {
352
        fat_mark_cluster(bs, dev_handle, FAT1, lifo[found],
343
        fat_mark_cluster(bs, dev_handle, FAT1, lifo[found],
353
            FAT_CLST_RES0);
344
            FAT_CLST_RES0);
354
    }
345
    }
355
   
346
   
356
    free(lifo);
347
    free(lifo);
357
    return ENOSPC;
348
    return ENOSPC;
358
}
349
}
359
 
350
 
360
/** Append a cluster chain to the last file cluster in all FATs.
351
/** Append a cluster chain to the last file cluster in all FATs.
361
 *
352
 *
362
 * @param bs        Buffer holding boot sector of the file system.
353
 * @param bs        Buffer holding boot sector of the file system.
363
 * @param nodep     Node representing the file.
354
 * @param nodep     Node representing the file.
364
 * @param mcl       First cluster of the cluster chain to append.
355
 * @param mcl       First cluster of the cluster chain to append.
365
 */
356
 */
366
void fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl)
357
void fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl)
367
{
358
{
368
    dev_handle_t dev_handle = nodep->idx->dev_handle;
359
    dev_handle_t dev_handle = nodep->idx->dev_handle;
369
    fat_cluster_t lcl;
360
    fat_cluster_t lcl;
370
    uint8_t fatno;
361
    uint8_t fatno;
371
 
362
 
372
    if (_fat_blcks_get(bs, dev_handle, nodep->firstc, &lcl) == 0) {
363
    if (fat_cluster_walk(bs, nodep->idx->dev_handle, nodep->firstc, &lcl,
-
 
364
        NULL, (uint16_t) -1) == 0) {
-
 
365
        /* No clusters allocated to the node yet. */
373
        nodep->firstc = host2uint16_t_le(mcl);
366
        nodep->firstc = host2uint16_t_le(mcl);
374
        nodep->dirty = true;        /* need to sync node */
367
        nodep->dirty = true;        /* need to sync node */
375
        return;
368
        return;
376
    }
369
    }
377
 
370
 
378
    for (fatno = FAT1; fatno < bs->fatcnt; fatno++)
371
    for (fatno = FAT1; fatno < bs->fatcnt; fatno++)
379
        fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl);
372
        fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl);
380
}
373
}
381
 
374
 
382
/**
375
/**
383
 * @}
376
 * @}
384
 */
377
 */
385
 
378