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2627 jermar 1
/*
2925 svoboda 2
 * Copyright (c) 2008 Jakub Jermar
2627 jermar 3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
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
15
 *   derived from this software without specific prior written permission.
16
 *
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
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
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
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
29
/** @addtogroup fs
30
 * @{
31
 */
32
 
33
/**
34
 * @file    fat_ops.c
35
 * @brief   Implementation of VFS operations for the FAT file system server.
36
 */
37
 
38
#include "fat.h"
3536 svoboda 39
#include "fat_dentry.h"
40
#include "fat_fat.h"
2638 jermar 41
#include "../../vfs/vfs.h"
2925 svoboda 42
#include <libfs.h>
3536 svoboda 43
#include <libblock.h>
2627 jermar 44
#include <ipc/ipc.h>
3425 svoboda 45
#include <ipc/services.h>
46
#include <ipc/devmap.h>
2627 jermar 47
#include <async.h>
48
#include <errno.h>
2925 svoboda 49
#include <string.h>
50
#include <byteorder.h>
51
#include <libadt/hash_table.h>
52
#include <libadt/list.h>
53
#include <assert.h>
54
#include <futex.h>
3425 svoboda 55
#include <sys/mman.h>
3536 svoboda 56
#include <align.h>
2627 jermar 57
 
4377 svoboda 58
#define FAT_NODE(node)  ((node) ? (fat_node_t *) (node)->data : NULL)
59
#define FS_NODE(node)   ((node) ? (node)->bp : NULL)
60
 
3011 svoboda 61
/** Futex protecting the list of cached free FAT nodes. */
62
static futex_t ffn_futex = FUTEX_INITIALIZER;
2925 svoboda 63
 
3011 svoboda 64
/** List of cached free FAT nodes. */
65
static LIST_INITIALIZE(ffn_head);
66
 
2925 svoboda 67
static void fat_node_initialize(fat_node_t *node)
68
{
3011 svoboda 69
    futex_initialize(&node->lock, 1);
4377 svoboda 70
    node->bp = NULL;
2925 svoboda 71
    node->idx = NULL;
72
    node->type = 0;
73
    link_initialize(&node->ffn_link);
74
    node->size = 0;
75
    node->lnkcnt = 0;
76
    node->refcnt = 0;
77
    node->dirty = false;
78
}
79
 
3536 svoboda 80
static void fat_node_sync(fat_node_t *node)
2925 svoboda 81
{
3536 svoboda 82
    block_t *b;
83
    fat_bs_t *bs;
84
    fat_dentry_t *d;
2925 svoboda 85
    uint16_t bps;
3536 svoboda 86
    unsigned dps;
2925 svoboda 87
 
3536 svoboda 88
    assert(node->dirty);
2925 svoboda 89
 
3536 svoboda 90
    bs = block_bb_get(node->idx->dev_handle);
91
    bps = uint16_t_le2host(bs->bps);
92
    dps = bps / sizeof(fat_dentry_t);
93
 
94
    /* Read the block that contains the dentry of interest. */
95
    b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
3597 svoboda 96
        (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
2925 svoboda 97
 
3536 svoboda 98
    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
2925 svoboda 99
 
3536 svoboda 100
    d->firstc = host2uint16_t_le(node->firstc);
3675 svoboda 101
    if (node->type == FAT_FILE) {
3536 svoboda 102
        d->size = host2uint32_t_le(node->size);
3675 svoboda 103
    } else if (node->type == FAT_DIRECTORY) {
104
        d->attr = FAT_ATTR_SUBDIR;
105
    }
3536 svoboda 106
 
3675 svoboda 107
    /* TODO: update other fields? (e.g time fields) */
108
 
3536 svoboda 109
    b->dirty = true;        /* need to sync block */
110
    block_put(b);
2925 svoboda 111
}
112
 
3597 svoboda 113
static fat_node_t *fat_node_get_new(void)
114
{
4377 svoboda 115
    fs_node_t *fn;
3597 svoboda 116
    fat_node_t *nodep;
117
 
118
    futex_down(&ffn_futex);
119
    if (!list_empty(&ffn_head)) {
120
        /* Try to use a cached free node structure. */
121
        fat_idx_t *idxp_tmp;
122
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
123
        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
124
            goto skip_cache;
125
        idxp_tmp = nodep->idx;
126
        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
127
            futex_up(&nodep->lock);
128
            goto skip_cache;
129
        }
130
        list_remove(&nodep->ffn_link);
131
        futex_up(&ffn_futex);
132
        if (nodep->dirty)
133
            fat_node_sync(nodep);
134
        idxp_tmp->nodep = NULL;
135
        futex_up(&nodep->lock);
136
        futex_up(&idxp_tmp->lock);
4377 svoboda 137
        fn = FS_NODE(nodep);
3597 svoboda 138
    } else {
139
skip_cache:
140
        /* Try to allocate a new node structure. */
141
        futex_up(&ffn_futex);
4377 svoboda 142
        fn = (fs_node_t *)malloc(sizeof(fs_node_t));
143
        if (!fn)
144
            return NULL;
3597 svoboda 145
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
4377 svoboda 146
        if (!nodep) {
147
            free(fn);
3597 svoboda 148
            return NULL;
4377 svoboda 149
        }
3597 svoboda 150
    }
151
    fat_node_initialize(nodep);
4377 svoboda 152
    fn->data = nodep;
153
    nodep->bp = fn;
3597 svoboda 154
 
155
    return nodep;
156
}
157
 
3011 svoboda 158
/** Internal version of fat_node_get().
159
 *
160
 * @param idxp      Locked index structure.
161
 */
4377 svoboda 162
static fat_node_t *fat_node_get_core(fat_idx_t *idxp)
2925 svoboda 163
{
164
    block_t *b;
3536 svoboda 165
    fat_bs_t *bs;
2925 svoboda 166
    fat_dentry_t *d;
3425 svoboda 167
    fat_node_t *nodep = NULL;
2925 svoboda 168
    unsigned bps;
3597 svoboda 169
    unsigned spc;
2925 svoboda 170
    unsigned dps;
171
 
3011 svoboda 172
    if (idxp->nodep) {
2925 svoboda 173
        /*
174
         * We are lucky.
175
         * The node is already instantiated in memory.
176
         */
3011 svoboda 177
        futex_down(&idxp->nodep->lock);
178
        if (!idxp->nodep->refcnt++)
3425 svoboda 179
            list_remove(&idxp->nodep->ffn_link);
3011 svoboda 180
        futex_up(&idxp->nodep->lock);
181
        return idxp->nodep;
2925 svoboda 182
    }
183
 
184
    /*
185
     * We must instantiate the node from the file system.
186
     */
187
 
3011 svoboda 188
    assert(idxp->pfc);
2925 svoboda 189
 
3597 svoboda 190
    nodep = fat_node_get_new();
191
    if (!nodep)
192
        return NULL;
2925 svoboda 193
 
3536 svoboda 194
    bs = block_bb_get(idxp->dev_handle);
195
    bps = uint16_t_le2host(bs->bps);
3597 svoboda 196
    spc = bs->spc;
2925 svoboda 197
    dps = bps / sizeof(fat_dentry_t);
198
 
199
    /* Read the block that contains the dentry of interest. */
3536 svoboda 200
    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
3597 svoboda 201
        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
2925 svoboda 202
    assert(b);
203
 
3011 svoboda 204
    d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
2925 svoboda 205
    if (d->attr & FAT_ATTR_SUBDIR) {
206
        /*
207
         * The only directory which does not have this bit set is the
208
         * root directory itself. The root directory node is handled
209
         * and initialized elsewhere.
210
         */
211
        nodep->type = FAT_DIRECTORY;
3425 svoboda 212
        /*
213
         * Unfortunately, the 'size' field of the FAT dentry is not
214
         * defined for the directory entry type. We must determine the
215
         * size of the directory by walking the FAT.
216
         */
3597 svoboda 217
        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
218
            uint16_t_le2host(d->firstc));
2925 svoboda 219
    } else {
220
        nodep->type = FAT_FILE;
3425 svoboda 221
        nodep->size = uint32_t_le2host(d->size);
2925 svoboda 222
    }
223
    nodep->firstc = uint16_t_le2host(d->firstc);
224
    nodep->lnkcnt = 1;
225
    nodep->refcnt = 1;
226
 
227
    block_put(b);
228
 
229
    /* Link the idx structure with the node structure. */
3011 svoboda 230
    nodep->idx = idxp;
231
    idxp->nodep = nodep;
2925 svoboda 232
 
233
    return nodep;
234
}
235
 
3623 svoboda 236
/*
237
 * Forward declarations of FAT libfs operations.
238
 */
4377 svoboda 239
static fs_node_t *fat_node_get(dev_handle_t, fs_index_t);
240
static void fat_node_put(fs_node_t *);
241
static fs_node_t *fat_create_node(dev_handle_t, int);
242
static int fat_destroy_node(fs_node_t *);
243
static int fat_link(fs_node_t *, fs_node_t *, const char *);
244
static int fat_unlink(fs_node_t *, fs_node_t *, const char *);
245
static fs_node_t *fat_match(fs_node_t *, const char *);
246
static fs_index_t fat_index_get(fs_node_t *);
247
static size_t fat_size_get(fs_node_t *);
248
static unsigned fat_lnkcnt_get(fs_node_t *);
249
static bool fat_has_children(fs_node_t *);
250
static fs_node_t *fat_root_get(dev_handle_t);
3623 svoboda 251
static char fat_plb_get_char(unsigned);
4377 svoboda 252
static bool fat_is_directory(fs_node_t *);
253
static bool fat_is_file(fs_node_t *node);
3623 svoboda 254
 
255
/*
256
 * FAT libfs operations.
257
 */
258
 
3011 svoboda 259
/** Instantiate a FAT in-core node. */
4377 svoboda 260
fs_node_t *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
3011 svoboda 261
{
4377 svoboda 262
    fat_node_t *nodep;
3011 svoboda 263
    fat_idx_t *idxp;
264
 
265
    idxp = fat_idx_get_by_index(dev_handle, index);
266
    if (!idxp)
267
        return NULL;
268
    /* idxp->lock held */
4377 svoboda 269
    nodep = fat_node_get_core(idxp);
3011 svoboda 270
    futex_up(&idxp->lock);
4377 svoboda 271
    return FS_NODE(nodep);
3011 svoboda 272
}
273
 
4377 svoboda 274
void fat_node_put(fs_node_t *fn)
2925 svoboda 275
{
4377 svoboda 276
    fat_node_t *nodep = FAT_NODE(fn);
3612 svoboda 277
    bool destroy = false;
2925 svoboda 278
 
3011 svoboda 279
    futex_down(&nodep->lock);
2925 svoboda 280
    if (!--nodep->refcnt) {
3612 svoboda 281
        if (nodep->idx) {
282
            futex_down(&ffn_futex);
283
            list_append(&nodep->ffn_link, &ffn_head);
284
            futex_up(&ffn_futex);
285
        } else {
286
            /*
287
             * The node does not have any index structure associated
288
             * with itself. This can only mean that we are releasing
289
             * the node after a failed attempt to allocate the index
290
             * structure for it.
291
             */
292
            destroy = true;
293
        }
2925 svoboda 294
    }
3011 svoboda 295
    futex_up(&nodep->lock);
4377 svoboda 296
    if (destroy) {
297
        free(nodep->bp);
298
        free(nodep);
299
    }
2925 svoboda 300
}
301
 
4377 svoboda 302
fs_node_t *fat_create_node(dev_handle_t dev_handle, int flags)
2925 svoboda 303
{
3612 svoboda 304
    fat_idx_t *idxp;
305
    fat_node_t *nodep;
3675 svoboda 306
    fat_bs_t *bs;
307
    fat_cluster_t mcl, lcl;
308
    uint16_t bps;
309
    int rc;
3612 svoboda 310
 
3675 svoboda 311
    bs = block_bb_get(dev_handle);
312
    bps = uint16_t_le2host(bs->bps);
313
    if (flags & L_DIRECTORY) {
314
        /* allocate a cluster */
315
        rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);
316
        if (rc != EOK)
317
            return NULL;
318
    }
319
 
3612 svoboda 320
    nodep = fat_node_get_new();
3675 svoboda 321
    if (!nodep) {
322
        fat_free_clusters(bs, dev_handle, mcl);
3612 svoboda 323
        return NULL;
3675 svoboda 324
    }
3612 svoboda 325
    idxp = fat_idx_get_new(dev_handle);
326
    if (!idxp) {
3675 svoboda 327
        fat_free_clusters(bs, dev_handle, mcl);
4377 svoboda 328
        fat_node_put(FS_NODE(nodep));
3612 svoboda 329
        return NULL;
330
    }
331
    /* idxp->lock held */
332
    if (flags & L_DIRECTORY) {
3675 svoboda 333
        int i;
334
        block_t *b;
335
 
336
        /*
337
         * Populate the new cluster with unused dentries.
338
         */
339
        for (i = 0; i < bs->spc; i++) {
340
            b = _fat_block_get(bs, dev_handle, mcl, i,
341
                BLOCK_FLAGS_NOREAD);
342
            /* mark all dentries as never-used */
343
            memset(b->data, 0, bps);
344
            b->dirty = false;
345
            block_put(b);
346
        }
3612 svoboda 347
        nodep->type = FAT_DIRECTORY;
3675 svoboda 348
        nodep->firstc = mcl;
349
        nodep->size = bps * bs->spc;
3612 svoboda 350
    } else {
351
        nodep->type = FAT_FILE;
3675 svoboda 352
        nodep->firstc = FAT_CLST_RES0;
353
        nodep->size = 0;
3612 svoboda 354
    }
355
    nodep->lnkcnt = 0;  /* not linked anywhere */
356
    nodep->refcnt = 1;
3675 svoboda 357
    nodep->dirty = true;
3612 svoboda 358
 
359
    nodep->idx = idxp;
360
    idxp->nodep = nodep;
361
 
362
    futex_up(&idxp->lock);
4377 svoboda 363
    return FS_NODE(nodep);
2925 svoboda 364
}
365
 
4377 svoboda 366
int fat_destroy_node(fs_node_t *fn)
2925 svoboda 367
{
4377 svoboda 368
    fat_node_t *nodep = FAT_NODE(fn);
3623 svoboda 369
    fat_bs_t *bs;
370
 
371
    /*
372
     * The node is not reachable from the file system. This means that the
373
     * link count should be zero and that the index structure cannot be
374
     * found in the position hash. Obviously, we don't need to lock the node
375
     * nor its index structure.
376
     */
377
    assert(nodep->lnkcnt == 0);
378
 
379
    /*
380
     * The node may not have any children.
381
     */
4377 svoboda 382
    assert(fat_has_children(fn) == false);
3623 svoboda 383
 
384
    bs = block_bb_get(nodep->idx->dev_handle);
385
    if (nodep->firstc != FAT_CLST_RES0) {
386
        assert(nodep->size);
387
        /* Free all clusters allocated to the node. */
388
        fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
389
    }
390
 
391
    fat_idx_destroy(nodep->idx);
4377 svoboda 392
    free(nodep->bp);
3623 svoboda 393
    free(nodep);
394
    return EOK;
2925 svoboda 395
}
396
 
4377 svoboda 397
int fat_link(fs_node_t *pfn, fs_node_t *cfn, const char *name)
2925 svoboda 398
{
4377 svoboda 399
    fat_node_t *parentp = FAT_NODE(pfn);
400
    fat_node_t *childp = FAT_NODE(cfn);
3675 svoboda 401
    fat_dentry_t *d;
402
    fat_bs_t *bs;
403
    block_t *b;
404
    int i, j;
405
    uint16_t bps;
406
    unsigned dps;
407
    unsigned blocks;
4377 svoboda 408
    fat_cluster_t mcl, lcl;
409
    int rc;
3675 svoboda 410
 
411
    futex_down(&childp->lock);
412
    if (childp->lnkcnt == 1) {
413
        /*
414
         * On FAT, we don't support multiple hard links.
415
         */
416
        futex_up(&childp->lock);
417
        return EMLINK;
418
    }
419
    assert(childp->lnkcnt == 0);
420
    futex_up(&childp->lock);
421
 
422
    if (!fat_dentry_name_verify(name)) {
423
        /*
424
         * Attempt to create unsupported name.
425
         */
426
        return ENOTSUP;
427
    }
428
 
429
    /*
430
     * Get us an unused parent node's dentry or grow the parent and allocate
431
     * a new one.
432
     */
433
 
434
    futex_down(&parentp->idx->lock);
435
    bs = block_bb_get(parentp->idx->dev_handle);
436
    bps = uint16_t_le2host(bs->bps);
437
    dps = bps / sizeof(fat_dentry_t);
438
 
439
    blocks = parentp->size / bps;
440
 
441
    for (i = 0; i < blocks; i++) {
442
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
443
        for (j = 0; j < dps; j++) {
444
            d = ((fat_dentry_t *)b->data) + j;
445
            switch (fat_classify_dentry(d)) {
446
            case FAT_DENTRY_SKIP:
447
            case FAT_DENTRY_VALID:
448
                /* skipping used and meta entries */
449
                continue;
450
            case FAT_DENTRY_FREE:
451
            case FAT_DENTRY_LAST:
452
                /* found an empty slot */
453
                goto hit;
454
            }
455
        }
456
        block_put(b);
457
    }
4377 svoboda 458
    j = 0;
3675 svoboda 459
 
460
    /*
461
     * We need to grow the parent in order to create a new unused dentry.
462
     */
4377 svoboda 463
    if (parentp->idx->pfc == FAT_CLST_ROOT) {
464
        /* Can't grow the root directory. */
465
        futex_up(&parentp->idx->lock);
466
        return ENOSPC;
467
    }
468
    rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);
469
    if (rc != EOK) {
470
        futex_up(&parentp->idx->lock);
471
        return rc;
472
    }
473
    fat_append_clusters(bs, parentp, mcl);
474
    b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);
475
    d = (fat_dentry_t *)b->data;
476
    /*
477
     * Clear all dentries in the block except for the first one (the first
478
     * dentry will be cleared in the next step).
479
     */
480
    memset(d + 1, 0, bps - sizeof(fat_dentry_t));
3675 svoboda 481
 
482
hit:
483
    /*
484
     * At this point we only establish the link between the parent and the
485
     * child.  The dentry, except of the name and the extension, will remain
4377 svoboda 486
     * uninitialized until the corresponding node is synced. Thus the valid
487
     * dentry data is kept in the child node structure.
3675 svoboda 488
     */
489
    memset(d, 0, sizeof(fat_dentry_t));
490
    fat_dentry_name_set(d, name);
491
    b->dirty = true;        /* need to sync block */
492
    block_put(b);
493
    futex_up(&parentp->idx->lock);
494
 
495
    futex_down(&childp->idx->lock);
496
 
497
    /*
498
     * If possible, create the Sub-directory Identifier Entry and the
499
     * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
500
     * are not mandatory according to Standard ECMA-107 and HelenOS VFS does
501
     * not use them anyway, so this is rather a sign of our good will.
502
     */
503
    b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE);
504
    d = (fat_dentry_t *)b->data;
505
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
4377 svoboda 506
        str_cmp(d->name, FAT_NAME_DOT) == 0) {
3675 svoboda 507
        memset(d, 0, sizeof(fat_dentry_t));
4377 svoboda 508
        str_cpy(d->name, 8, FAT_NAME_DOT);
509
        str_cpy(d->ext, 3, FAT_EXT_PAD);
3675 svoboda 510
        d->attr = FAT_ATTR_SUBDIR;
511
        d->firstc = host2uint16_t_le(childp->firstc);
512
        /* TODO: initialize also the date/time members. */
513
    }
514
    d++;
515
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
4377 svoboda 516
        str_cmp(d->name, FAT_NAME_DOT_DOT) == 0) {
3675 svoboda 517
        memset(d, 0, sizeof(fat_dentry_t));
4377 svoboda 518
        str_cpy(d->name, 8, FAT_NAME_DOT_DOT);
519
        str_cpy(d->ext, 3, FAT_EXT_PAD);
3675 svoboda 520
        d->attr = FAT_ATTR_SUBDIR;
521
        d->firstc = (parentp->firstc == FAT_CLST_ROOT) ?
522
            host2uint16_t_le(FAT_CLST_RES0) :
523
            host2uint16_t_le(parentp->firstc);
524
        /* TODO: initialize also the date/time members. */
525
    }
526
    b->dirty = true;        /* need to sync block */
527
    block_put(b);
528
 
529
    childp->idx->pfc = parentp->firstc;
530
    childp->idx->pdi = i * dps + j;
531
    futex_up(&childp->idx->lock);
532
 
533
    futex_down(&childp->lock);
534
    childp->lnkcnt = 1;
535
    childp->dirty = true;       /* need to sync node */
536
    futex_up(&childp->lock);
537
 
538
    /*
539
     * Hash in the index structure into the position hash.
540
     */
541
    fat_idx_hashin(childp->idx);
542
 
543
    return EOK;
2925 svoboda 544
}
545
 
4377 svoboda 546
int fat_unlink(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
2925 svoboda 547
{
4377 svoboda 548
    fat_node_t *parentp = FAT_NODE(pfn);
549
    fat_node_t *childp = FAT_NODE(cfn);
3675 svoboda 550
    fat_bs_t *bs;
551
    fat_dentry_t *d;
552
    uint16_t bps;
553
    block_t *b;
554
 
4377 svoboda 555
    if (!parentp)
556
        return EBUSY;
557
 
558
    if (fat_has_children(cfn))
559
        return ENOTEMPTY;
560
 
3675 svoboda 561
    futex_down(&parentp->lock);
562
    futex_down(&childp->lock);
563
    assert(childp->lnkcnt == 1);
564
    futex_down(&childp->idx->lock);
565
    bs = block_bb_get(childp->idx->dev_handle);
566
    bps = uint16_t_le2host(bs->bps);
567
 
568
    b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc,
569
        (childp->idx->pdi * sizeof(fat_dentry_t)) / bps,
570
        BLOCK_FLAGS_NONE);
571
    d = (fat_dentry_t *)b->data +
572
        (childp->idx->pdi % (bps / sizeof(fat_dentry_t)));
573
    /* mark the dentry as not-currently-used */
574
    d->name[0] = FAT_DENTRY_ERASED;
575
    b->dirty = true;        /* need to sync block */
576
    block_put(b);
577
 
578
    /* remove the index structure from the position hash */
579
    fat_idx_hashout(childp->idx);
580
    /* clear position information */
581
    childp->idx->pfc = FAT_CLST_RES0;
582
    childp->idx->pdi = 0;
583
    futex_up(&childp->idx->lock);
584
    childp->lnkcnt = 0;
585
    childp->dirty = true;
586
    futex_up(&childp->lock);
587
    futex_up(&parentp->lock);
588
 
589
    return EOK;
2925 svoboda 590
}
591
 
4377 svoboda 592
fs_node_t *fat_match(fs_node_t *pfn, const char *component)
2925 svoboda 593
{
3536 svoboda 594
    fat_bs_t *bs;
4377 svoboda 595
    fat_node_t *parentp = FAT_NODE(pfn);
2925 svoboda 596
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
597
    unsigned i, j;
598
    unsigned bps;       /* bytes per sector */
599
    unsigned dps;       /* dentries per sector */
600
    unsigned blocks;
601
    fat_dentry_t *d;
602
    block_t *b;
603
 
3011 svoboda 604
    futex_down(&parentp->idx->lock);
3536 svoboda 605
    bs = block_bb_get(parentp->idx->dev_handle);
606
    bps = uint16_t_le2host(bs->bps);
2925 svoboda 607
    dps = bps / sizeof(fat_dentry_t);
3536 svoboda 608
    blocks = parentp->size / bps;
2925 svoboda 609
    for (i = 0; i < blocks; i++) {
3597 svoboda 610
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
3536 svoboda 611
        for (j = 0; j < dps; j++) {
2925 svoboda 612
            d = ((fat_dentry_t *)b->data) + j;
613
            switch (fat_classify_dentry(d)) {
614
            case FAT_DENTRY_SKIP:
3675 svoboda 615
            case FAT_DENTRY_FREE:
2639 jermar 616
                continue;
2925 svoboda 617
            case FAT_DENTRY_LAST:
618
                block_put(b);
3011 svoboda 619
                futex_up(&parentp->idx->lock);
2925 svoboda 620
                return NULL;
621
            default:
622
            case FAT_DENTRY_VALID:
3675 svoboda 623
                fat_dentry_name_get(d, name);
2925 svoboda 624
                break;
2639 jermar 625
            }
3675 svoboda 626
            if (fat_dentry_namecmp(name, component) == 0) {
2925 svoboda 627
                /* hit */
4377 svoboda 628
                fat_node_t *nodep;
3011 svoboda 629
                /*
630
                 * Assume tree hierarchy for locking.  We
631
                 * already have the parent and now we are going
632
                 * to lock the child.  Never lock in the oposite
633
                 * order.
634
                 */
2925 svoboda 635
                fat_idx_t *idx = fat_idx_get_by_pos(
636
                    parentp->idx->dev_handle, parentp->firstc,
637
                    i * dps + j);
3011 svoboda 638
                futex_up(&parentp->idx->lock);
2925 svoboda 639
                if (!idx) {
640
                    /*
641
                     * Can happen if memory is low or if we
642
                     * run out of 32-bit indices.
643
                     */
644
                    block_put(b);
645
                    return NULL;
646
                }
4377 svoboda 647
                nodep = fat_node_get_core(idx);
3011 svoboda 648
                futex_up(&idx->lock);
2925 svoboda 649
                block_put(b);
4377 svoboda 650
                return FS_NODE(nodep);
2925 svoboda 651
            }
2639 jermar 652
        }
2925 svoboda 653
        block_put(b);
2639 jermar 654
    }
3536 svoboda 655
 
3011 svoboda 656
    futex_up(&parentp->idx->lock);
2925 svoboda 657
    return NULL;
658
}
659
 
4377 svoboda 660
fs_index_t fat_index_get(fs_node_t *fn)
2925 svoboda 661
{
4377 svoboda 662
    return FAT_NODE(fn)->idx->index;
2638 jermar 663
}
664
 
4377 svoboda 665
size_t fat_size_get(fs_node_t *fn)
2627 jermar 666
{
4377 svoboda 667
    return FAT_NODE(fn)->size;
2925 svoboda 668
}
2627 jermar 669
 
4377 svoboda 670
unsigned fat_lnkcnt_get(fs_node_t *fn)
2925 svoboda 671
{
4377 svoboda 672
    return FAT_NODE(fn)->lnkcnt;
2925 svoboda 673
}
674
 
4377 svoboda 675
bool fat_has_children(fs_node_t *fn)
2925 svoboda 676
{
3536 svoboda 677
    fat_bs_t *bs;
4377 svoboda 678
    fat_node_t *nodep = FAT_NODE(fn);
2925 svoboda 679
    unsigned bps;
680
    unsigned dps;
681
    unsigned blocks;
682
    block_t *b;
683
    unsigned i, j;
684
 
685
    if (nodep->type != FAT_DIRECTORY)
686
        return false;
3536 svoboda 687
 
3011 svoboda 688
    futex_down(&nodep->idx->lock);
3536 svoboda 689
    bs = block_bb_get(nodep->idx->dev_handle);
690
    bps = uint16_t_le2host(bs->bps);
2925 svoboda 691
    dps = bps / sizeof(fat_dentry_t);
692
 
3536 svoboda 693
    blocks = nodep->size / bps;
2925 svoboda 694
 
695
    for (i = 0; i < blocks; i++) {
696
        fat_dentry_t *d;
2627 jermar 697
 
3597 svoboda 698
        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
3536 svoboda 699
        for (j = 0; j < dps; j++) {
2925 svoboda 700
            d = ((fat_dentry_t *)b->data) + j;
701
            switch (fat_classify_dentry(d)) {
702
            case FAT_DENTRY_SKIP:
3675 svoboda 703
            case FAT_DENTRY_FREE:
2925 svoboda 704
                continue;
705
            case FAT_DENTRY_LAST:
706
                block_put(b);
3011 svoboda 707
                futex_up(&nodep->idx->lock);
2925 svoboda 708
                return false;
709
            default:
710
            case FAT_DENTRY_VALID:
711
                block_put(b);
3011 svoboda 712
                futex_up(&nodep->idx->lock);
2925 svoboda 713
                return true;
714
            }
715
            block_put(b);
3011 svoboda 716
            futex_up(&nodep->idx->lock);
2925 svoboda 717
            return true;
718
        }
719
        block_put(b);
720
    }
721
 
3011 svoboda 722
    futex_up(&nodep->idx->lock);
2925 svoboda 723
    return false;
2627 jermar 724
}
725
 
4377 svoboda 726
fs_node_t *fat_root_get(dev_handle_t dev_handle)
2925 svoboda 727
{
3424 svoboda 728
    return fat_node_get(dev_handle, 0);
2925 svoboda 729
}
730
 
3623 svoboda 731
char fat_plb_get_char(unsigned pos)
2925 svoboda 732
{
733
    return fat_reg.plb_ro[pos % PLB_SIZE];
734
}
735
 
4377 svoboda 736
bool fat_is_directory(fs_node_t *fn)
2925 svoboda 737
{
4377 svoboda 738
    return FAT_NODE(fn)->type == FAT_DIRECTORY;
2925 svoboda 739
}
740
 
4377 svoboda 741
bool fat_is_file(fs_node_t *fn)
2925 svoboda 742
{
4377 svoboda 743
    return FAT_NODE(fn)->type == FAT_FILE;
2925 svoboda 744
}
745
 
746
/** libfs operations */
747
libfs_ops_t fat_libfs_ops = {
748
    .match = fat_match,
749
    .node_get = fat_node_get,
750
    .node_put = fat_node_put,
3612 svoboda 751
    .create = fat_create_node,
752
    .destroy = fat_destroy_node,
2925 svoboda 753
    .link = fat_link,
754
    .unlink = fat_unlink,
755
    .index_get = fat_index_get,
756
    .size_get = fat_size_get,
757
    .lnkcnt_get = fat_lnkcnt_get,
758
    .has_children = fat_has_children,
759
    .root_get = fat_root_get,
760
    .plb_get_char = fat_plb_get_char,
761
    .is_directory = fat_is_directory,
762
    .is_file = fat_is_file
763
};
764
 
3675 svoboda 765
/*
766
 * VFS operations.
767
 */
768
 
3424 svoboda 769
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
770
{
771
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
3536 svoboda 772
    fat_bs_t *bs;
3425 svoboda 773
    uint16_t bps;
3424 svoboda 774
    uint16_t rde;
775
    int rc;
776
 
4377 svoboda 777
    /* accept the mount options */
778
    ipc_callid_t callid;
779
    size_t size;
780
    if (!ipc_data_write_receive(&callid, &size)) {
781
        ipc_answer_0(callid, EINVAL);
782
        ipc_answer_0(rid, EINVAL);
783
        return;
784
    }
785
    char *opts = malloc(size + 1);
786
    if (!opts) {
787
        ipc_answer_0(callid, ENOMEM);
788
        ipc_answer_0(rid, ENOMEM);
789
        return;
790
    }
791
    ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);
792
    if (retval != EOK) {
793
        ipc_answer_0(rid, retval);
794
        free(opts);
795
        return;
796
    }
797
    opts[size] = '\0';
798
 
3536 svoboda 799
    /* initialize libblock */
3597 svoboda 800
    rc = block_init(dev_handle, BS_SIZE);
3425 svoboda 801
    if (rc != EOK) {
3597 svoboda 802
        ipc_answer_0(rid, rc);
3425 svoboda 803
        return;
804
    }
805
 
3597 svoboda 806
    /* prepare the boot block */
807
    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
808
    if (rc != EOK) {
809
        block_fini(dev_handle);
810
        ipc_answer_0(rid, rc);
811
        return;
812
    }
813
 
3536 svoboda 814
    /* get the buffer with the boot sector */
815
    bs = block_bb_get(dev_handle);
816
 
3424 svoboda 817
    /* Read the number of root directory entries. */
3536 svoboda 818
    bps = uint16_t_le2host(bs->bps);
819
    rde = uint16_t_le2host(bs->root_ent_max);
3424 svoboda 820
 
3425 svoboda 821
    if (bps != BS_SIZE) {
3536 svoboda 822
        block_fini(dev_handle);
3425 svoboda 823
        ipc_answer_0(rid, ENOTSUP);
824
        return;
825
    }
826
 
3597 svoboda 827
    /* Initialize the block cache */
828
    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
829
    if (rc != EOK) {
830
        block_fini(dev_handle);
831
        ipc_answer_0(rid, rc);
832
        return;
833
    }
834
 
3424 svoboda 835
    rc = fat_idx_init_by_dev_handle(dev_handle);
836
    if (rc != EOK) {
3536 svoboda 837
        block_fini(dev_handle);
3424 svoboda 838
        ipc_answer_0(rid, rc);
839
        return;
840
    }
841
 
842
    /* Initialize the root node. */
4377 svoboda 843
    fs_node_t *rfn = (fs_node_t *)malloc(sizeof(fs_node_t));
844
    if (!rfn) {
845
        block_fini(dev_handle);
846
        fat_idx_fini_by_dev_handle(dev_handle);
847
        ipc_answer_0(rid, ENOMEM);
848
        return;
849
    }
3424 svoboda 850
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
851
    if (!rootp) {
4377 svoboda 852
        free(rfn);
3536 svoboda 853
        block_fini(dev_handle);
3424 svoboda 854
        fat_idx_fini_by_dev_handle(dev_handle);
855
        ipc_answer_0(rid, ENOMEM);
856
        return;
857
    }
858
    fat_node_initialize(rootp);
859
 
860
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
861
    if (!ridxp) {
4377 svoboda 862
        free(rfn);
863
        free(rootp);
3536 svoboda 864
        block_fini(dev_handle);
3424 svoboda 865
        fat_idx_fini_by_dev_handle(dev_handle);
866
        ipc_answer_0(rid, ENOMEM);
867
        return;
868
    }
869
    assert(ridxp->index == 0);
870
    /* ridxp->lock held */
871
 
872
    rootp->type = FAT_DIRECTORY;
873
    rootp->firstc = FAT_CLST_ROOT;
874
    rootp->refcnt = 1;
3425 svoboda 875
    rootp->lnkcnt = 0;  /* FS root is not linked */
3424 svoboda 876
    rootp->size = rde * sizeof(fat_dentry_t);
877
    rootp->idx = ridxp;
878
    ridxp->nodep = rootp;
4377 svoboda 879
    rootp->bp = rfn;
880
    rfn->data = rootp;
3424 svoboda 881
 
882
    futex_up(&ridxp->lock);
883
 
3425 svoboda 884
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
3424 svoboda 885
}
886
 
887
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
888
{
889
    ipc_answer_0(rid, ENOTSUP);
890
}
891
 
2925 svoboda 892
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
893
{
894
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
895
}
896
 
3425 svoboda 897
void fat_read(ipc_callid_t rid, ipc_call_t *request)
898
{
899
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
900
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
901
    off_t pos = (off_t)IPC_GET_ARG3(*request);
4377 svoboda 902
    fs_node_t *fn = fat_node_get(dev_handle, index);
903
    fat_node_t *nodep;
3536 svoboda 904
    fat_bs_t *bs;
905
    uint16_t bps;
3425 svoboda 906
    size_t bytes;
907
    block_t *b;
908
 
4377 svoboda 909
    if (!fn) {
3425 svoboda 910
        ipc_answer_0(rid, ENOENT);
911
        return;
912
    }
4377 svoboda 913
    nodep = FAT_NODE(fn);
3425 svoboda 914
 
915
    ipc_callid_t callid;
916
    size_t len;
917
    if (!ipc_data_read_receive(&callid, &len)) {
4377 svoboda 918
        fat_node_put(fn);
3425 svoboda 919
        ipc_answer_0(callid, EINVAL);
920
        ipc_answer_0(rid, EINVAL);
921
        return;
922
    }
923
 
3536 svoboda 924
    bs = block_bb_get(dev_handle);
925
    bps = uint16_t_le2host(bs->bps);
926
 
3425 svoboda 927
    if (nodep->type == FAT_FILE) {
928
        /*
929
         * Our strategy for regular file reads is to read one block at
930
         * most and make use of the possibility to return less data than
931
         * requested. This keeps the code very simple.
932
         */
3536 svoboda 933
        if (pos >= nodep->size) {
934
            /* reading beyond the EOF */
935
            bytes = 0;
936
            (void) ipc_data_read_finalize(callid, NULL, 0);
937
        } else {
938
            bytes = min(len, bps - pos % bps);
939
            bytes = min(bytes, nodep->size - pos);
3597 svoboda 940
            b = fat_block_get(bs, nodep, pos / bps,
941
                BLOCK_FLAGS_NONE);
3536 svoboda 942
            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
943
                bytes);
944
            block_put(b);
945
        }
3425 svoboda 946
    } else {
947
        unsigned bnum;
948
        off_t spos = pos;
949
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
950
        fat_dentry_t *d;
951
 
952
        assert(nodep->type == FAT_DIRECTORY);
953
        assert(nodep->size % bps == 0);
954
        assert(bps % sizeof(fat_dentry_t) == 0);
955
 
956
        /*
957
         * Our strategy for readdir() is to use the position pointer as
958
         * an index into the array of all dentries. On entry, it points
959
         * to the first unread dentry. If we skip any dentries, we bump
960
         * the position pointer accordingly.
961
         */
962
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
963
        while (bnum < nodep->size / bps) {
964
            off_t o;
965
 
3597 svoboda 966
            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
3425 svoboda 967
            for (o = pos % (bps / sizeof(fat_dentry_t));
968
                o < bps / sizeof(fat_dentry_t);
969
                o++, pos++) {
970
                d = ((fat_dentry_t *)b->data) + o;
971
                switch (fat_classify_dentry(d)) {
972
                case FAT_DENTRY_SKIP:
3675 svoboda 973
                case FAT_DENTRY_FREE:
3425 svoboda 974
                    continue;
975
                case FAT_DENTRY_LAST:
976
                    block_put(b);
977
                    goto miss;
978
                default:
979
                case FAT_DENTRY_VALID:
3675 svoboda 980
                    fat_dentry_name_get(d, name);
3425 svoboda 981
                    block_put(b);
982
                    goto hit;
983
                }
984
            }
985
            block_put(b);
986
            bnum++;
987
        }
988
miss:
4377 svoboda 989
        fat_node_put(fn);
3425 svoboda 990
        ipc_answer_0(callid, ENOENT);
991
        ipc_answer_1(rid, ENOENT, 0);
992
        return;
993
hit:
4377 svoboda 994
        (void) ipc_data_read_finalize(callid, name, str_size(name) + 1);
3425 svoboda 995
        bytes = (pos - spos) + 1;
996
    }
997
 
4377 svoboda 998
    fat_node_put(fn);
3425 svoboda 999
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
1000
}
1001
 
3536 svoboda 1002
void fat_write(ipc_callid_t rid, ipc_call_t *request)
1003
{
1004
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1005
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1006
    off_t pos = (off_t)IPC_GET_ARG3(*request);
4377 svoboda 1007
    fs_node_t *fn = fat_node_get(dev_handle, index);
1008
    fat_node_t *nodep;
3536 svoboda 1009
    fat_bs_t *bs;
1010
    size_t bytes;
1011
    block_t *b;
1012
    uint16_t bps;
1013
    unsigned spc;
3597 svoboda 1014
    unsigned bpc;       /* bytes per cluster */
3536 svoboda 1015
    off_t boundary;
3597 svoboda 1016
    int flags = BLOCK_FLAGS_NONE;
3536 svoboda 1017
 
4377 svoboda 1018
    if (!fn) {
3536 svoboda 1019
        ipc_answer_0(rid, ENOENT);
1020
        return;
1021
    }
4377 svoboda 1022
    nodep = FAT_NODE(fn);
3536 svoboda 1023
 
1024
    ipc_callid_t callid;
1025
    size_t len;
1026
    if (!ipc_data_write_receive(&callid, &len)) {
4377 svoboda 1027
        fat_node_put(fn);
3536 svoboda 1028
        ipc_answer_0(callid, EINVAL);
1029
        ipc_answer_0(rid, EINVAL);
1030
        return;
1031
    }
1032
 
3597 svoboda 1033
    bs = block_bb_get(dev_handle);
1034
    bps = uint16_t_le2host(bs->bps);
1035
    spc = bs->spc;
1036
    bpc = bps * spc;
1037
 
3536 svoboda 1038
    /*
1039
     * In all scenarios, we will attempt to write out only one block worth
1040
     * of data at maximum. There might be some more efficient approaches,
1041
     * but this one greatly simplifies fat_write(). Note that we can afford
1042
     * to do this because the client must be ready to handle the return
1043
     * value signalizing a smaller number of bytes written.
1044
     */
1045
    bytes = min(len, bps - pos % bps);
3597 svoboda 1046
    if (bytes == bps)
1047
        flags |= BLOCK_FLAGS_NOREAD;
3536 svoboda 1048
 
3597 svoboda 1049
    boundary = ROUND_UP(nodep->size, bpc);
3536 svoboda 1050
    if (pos < boundary) {
1051
        /*
1052
         * This is the easier case - we are either overwriting already
1053
         * existing contents or writing behind the EOF, but still within
1054
         * the limits of the last cluster. The node size may grow to the
1055
         * next block size boundary.
1056
         */
1057
        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
3597 svoboda 1058
        b = fat_block_get(bs, nodep, pos / bps, flags);
3536 svoboda 1059
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1060
            bytes);
1061
        b->dirty = true;        /* need to sync block */
1062
        block_put(b);
1063
        if (pos + bytes > nodep->size) {
1064
            nodep->size = pos + bytes;
1065
            nodep->dirty = true;    /* need to sync node */
1066
        }
3597 svoboda 1067
        ipc_answer_2(rid, EOK, bytes, nodep->size);
4377 svoboda 1068
        fat_node_put(fn);
3536 svoboda 1069
        return;
1070
    } else {
1071
        /*
1072
         * This is the more difficult case. We must allocate new
1073
         * clusters for the node and zero them out.
1074
         */
1075
        int status;
1076
        unsigned nclsts;
3597 svoboda 1077
        fat_cluster_t mcl, lcl;
1078
 
1079
        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
3536 svoboda 1080
        /* create an independent chain of nclsts clusters in all FATs */
3597 svoboda 1081
        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
3536 svoboda 1082
        if (status != EOK) {
1083
            /* could not allocate a chain of nclsts clusters */
4377 svoboda 1084
            fat_node_put(fn);
3536 svoboda 1085
            ipc_answer_0(callid, status);
1086
            ipc_answer_0(rid, status);
1087
            return;
1088
        }
1089
        /* zero fill any gaps */
1090
        fat_fill_gap(bs, nodep, mcl, pos);
3597 svoboda 1091
        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
1092
            flags);
3536 svoboda 1093
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1094
            bytes);
1095
        b->dirty = true;        /* need to sync block */
1096
        block_put(b);
1097
        /*
1098
         * Append the cluster chain starting in mcl to the end of the
1099
         * node's cluster chain.
1100
         */
1101
        fat_append_clusters(bs, nodep, mcl);
1102
        nodep->size = pos + bytes;
1103
        nodep->dirty = true;        /* need to sync node */
3597 svoboda 1104
        ipc_answer_2(rid, EOK, bytes, nodep->size);
4377 svoboda 1105
        fat_node_put(fn);
3536 svoboda 1106
        return;
1107
    }
1108
}
1109
 
3597 svoboda 1110
void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
1111
{
1112
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1113
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1114
    size_t size = (off_t)IPC_GET_ARG3(*request);
4377 svoboda 1115
    fs_node_t *fn = fat_node_get(dev_handle, index);
1116
    fat_node_t *nodep;
3597 svoboda 1117
    fat_bs_t *bs;
1118
    uint16_t bps;
1119
    uint8_t spc;
1120
    unsigned bpc;   /* bytes per cluster */
1121
    int rc;
1122
 
4377 svoboda 1123
    if (!fn) {
3597 svoboda 1124
        ipc_answer_0(rid, ENOENT);
1125
        return;
1126
    }
4377 svoboda 1127
    nodep = FAT_NODE(fn);
3597 svoboda 1128
 
1129
    bs = block_bb_get(dev_handle);
1130
    bps = uint16_t_le2host(bs->bps);
1131
    spc = bs->spc;
1132
    bpc = bps * spc;
1133
 
1134
    if (nodep->size == size) {
1135
        rc = EOK;
1136
    } else if (nodep->size < size) {
1137
        /*
1138
         * The standard says we have the freedom to grow the node.
1139
         * For now, we simply return an error.
1140
         */
1141
        rc = EINVAL;
1142
    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
1143
        /*
1144
         * The node will be shrunk, but no clusters will be deallocated.
1145
         */
1146
        nodep->size = size;
1147
        nodep->dirty = true;        /* need to sync node */
1148
        rc = EOK;  
1149
    } else {
1150
        /*
1151
         * The node will be shrunk, clusters will be deallocated.
1152
         */
1153
        if (size == 0) {
1154
            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
1155
        } else {
1156
            fat_cluster_t lastc;
1157
            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
1158
                &lastc, (size - 1) / bpc);
1159
            fat_chop_clusters(bs, nodep, lastc);
1160
        }
1161
        nodep->size = size;
1162
        nodep->dirty = true;        /* need to sync node */
1163
        rc = EOK;  
1164
    }
4377 svoboda 1165
    fat_node_put(fn);
3597 svoboda 1166
    ipc_answer_0(rid, rc);
1167
    return;
1168
}
1169
 
3623 svoboda 1170
void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
1171
{
1172
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1173
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1174
    int rc;
1175
 
4377 svoboda 1176
    fs_node_t *fn = fat_node_get(dev_handle, index);
1177
    if (!fn) {
3623 svoboda 1178
        ipc_answer_0(rid, ENOENT);
1179
        return;
1180
    }
1181
 
4377 svoboda 1182
    rc = fat_destroy_node(fn);
3623 svoboda 1183
    ipc_answer_0(rid, rc);
1184
}
1185
 
2627 jermar 1186
/**
1187
 * @}
1188
 */