WebSVN – HelenOS – Diff – /branches/dynload/uspace/srv/fs/fat/fat_fat.c


/*
 * Copyright (c) 2008 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/** @addtogroup fs
 * @{
 */
 
/**
 * @file    fat_fat.c
 * @brief   Functions that manipulate the File Allocation Tables.
 */
 
#include "fat_fat.h"
#include "fat_dentry.h"
#include "fat.h"
#include "../../vfs/vfs.h"
#include <libfs.h>
#include <errno.h>
#include <byteorder.h>
#include <align.h>
#include <assert.h>
#include <futex.h>
 
/**
 * The fat_alloc_lock futex protects all copies of the File Allocation Table
 * during allocation of clusters. The lock does not have to be held durring
 * deallocation of clusters.
 */  
static futex_t fat_alloc_lock = FUTEX_INITIALIZER;
 
block_t *
_fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
    off_t offset)
{
    block_t *b;
    unsigned bps;
    unsigned spc;
    unsigned rscnt;     /* block address of the first FAT */
    unsigned fatcnt;
    unsigned rde;
    unsigned rds;       /* root directory size */
    unsigned sf;
    unsigned ssa;       /* size of the system area */
    unsigned clusters;
    fat_cluster_t clst = firstc;
    unsigned i;
 
    bps = uint16_t_le2host(bs->bps);
    spc = bs->spc;
    rscnt = uint16_t_le2host(bs->rscnt);
    fatcnt = bs->fatcnt;
    rde = uint16_t_le2host(bs->root_ent_max);
    sf = uint16_t_le2host(bs->sec_per_fat);
 
    rds = (sizeof(fat_dentry_t) * rde) / bps;
    rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
    ssa = rscnt + fatcnt * sf + rds;
 
    if (firstc == FAT_CLST_ROOT) {
        /* root directory special case */
        assert(offset < rds);
        b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
        return b;
    }
 
    clusters = offset / spc;
    for (i = 0; i < clusters; i++) {
        unsigned fsec;  /* sector offset relative to FAT1 */
        unsigned fidx;  /* FAT1 entry index */
 
        assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
        fidx = clst % (bps / sizeof(fat_cluster_t));
        /* read FAT1 */
        b = block_get(dev_handle, rscnt + fsec, bps);
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
        assert(clst != FAT_CLST_BAD);
        assert(clst < FAT_CLST_LAST1);
        block_put(b);
    }
 
    b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
        offset % spc, bps);
 
    return b;
}
 
/** Return number of blocks allocated to a file.
 *
 * @param bs        Buffer holding the boot sector for the file.
 * @param dev_handle    Device handle of the device with the file.
 * @param firstc    First cluster of the file.
 * @param lastc     If non-NULL, output argument holding the
 *          last cluster.
 *
 * @return      Number of blocks allocated to the file.
 */
uint16_t
_fat_blcks_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
    fat_cluster_t *lastc)
{
    block_t *b;
    unsigned bps;
    unsigned spc;
    unsigned rscnt;     /* block address of the first FAT */
    unsigned clusters = 0;
    fat_cluster_t clst = firstc;
 
    bps = uint16_t_le2host(bs->bps);
    spc = bs->spc;
    rscnt = uint16_t_le2host(bs->rscnt);
 
    if (firstc == FAT_CLST_RES0) {
        /* No space allocated to the file. */
        if (lastc)
            *lastc = firstc;
        return 0;
    }
 
    while (clst < FAT_CLST_LAST1) {
        unsigned fsec;  /* sector offset relative to FAT1 */
        unsigned fidx;  /* FAT1 entry index */
 
        assert(clst >= FAT_CLST_FIRST);
        if (lastc)
            *lastc = clst;      /* remember the last cluster */
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
        fidx = clst % (bps / sizeof(fat_cluster_t));
        /* read FAT1 */
        b = block_get(dev_handle, rscnt + fsec, bps);
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
        assert(clst != FAT_CLST_BAD);
        block_put(b);
        clusters++;
    }
 
    if (lastc)
        *lastc = clst;
    return clusters * spc;
}
 
/** Fill the gap between EOF and a new file position.
 *
 * @param bs        Buffer holding the boot sector for nodep.
 * @param nodep     FAT node with the gap.
 * @param mcl       First cluster in an independent cluster chain that will
 *          be later appended to the end of the node's own cluster
 *          chain. If pos is still in the last allocated cluster,
 *          this argument is ignored.
 * @param pos       Position in the last node block.
 */
void fat_fill_gap(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl, off_t pos)
{
    uint16_t bps;
    unsigned spc;
    block_t *b;
    off_t o, boundary;
 
    bps = uint16_t_le2host(bs->bps);
    spc = bs->spc;
   
    boundary = ROUND_UP(nodep->size, bps * spc);
 
    /* zero out already allocated space */
    for (o = nodep->size - 1; o < pos && o < boundary;
        o = ALIGN_DOWN(o + bps, bps)) {
        b = fat_block_get(bs, nodep, o / bps);
        memset(b->data + o % bps, 0, bps - o % bps);
        b->dirty = true;        /* need to sync node */
        block_put(b);
    }
   
    if (o >= pos)
        return;
   
    /* zero out the initial part of the new cluster chain */
    for (o = boundary; o < pos; o += bps) {
        b = _fat_block_get(bs, nodep->idx->dev_handle, mcl,
            (o - boundary) / bps);
        memset(b->data, 0, min(bps, pos - o));
        b->dirty = true;        /* need to sync node */
        block_put(b);
    }
}
 
void
fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
    fat_cluster_t clst, fat_cluster_t value)
{
    block_t *b;
    uint16_t bps;
    uint16_t rscnt;
    uint16_t sf;
    fat_cluster_t *cp;
 
    bps = uint16_t_le2host(bs->bps);
    rscnt = uint16_t_le2host(bs->rscnt);
    sf = uint16_t_le2host(bs->sec_per_fat);
 
    assert(fatno < bs->fatcnt);
    b = block_get(dev_handle, rscnt + sf * fatno +
        (clst * sizeof(fat_cluster_t)) / bps, bps);
    cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));
    *cp = host2uint16_t_le(value);
    b->dirty = true;        /* need to sync block */
    block_put(b);
}
 
void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,
    fat_cluster_t *lifo, unsigned nclsts)
{
    uint8_t fatno;
    unsigned c;
 
    for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) {
        for (c = 0; c < nclsts; c++) {
            fat_mark_cluster(bs, dev_handle, fatno, lifo[c],
                c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]);
        }
    }
}
 
int
fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,
    fat_cluster_t *mcl, fat_cluster_t *lcl)
{
    uint16_t bps;
    uint16_t rscnt;
    uint16_t sf;
    block_t *blk;
    fat_cluster_t *lifo;    /* stack for storing free cluster numbers */
    unsigned found = 0; /* top of the free cluster number stack */
    unsigned b, c, cl;
 
    lifo = (fat_cluster_t *) malloc(nclsts * sizeof(fat_cluster_t));
    if (lifo)
        return ENOMEM;
   
    bps = uint16_t_le2host(bs->bps);
    rscnt = uint16_t_le2host(bs->rscnt);
    sf = uint16_t_le2host(bs->sec_per_fat);
   
    /*
     * Search FAT1 for unused clusters.
     */
    futex_down(&fat_alloc_lock);
    for (b = 0, cl = 0; b < sf; blk++) {
        blk = block_get(dev_handle, rscnt + b, bps);
        for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {
            fat_cluster_t *clst = (fat_cluster_t *)blk->data + c;
            if (uint16_t_le2host(*clst) == FAT_CLST_RES0) {
                /*
                 * The cluster is free. Put it into our stack
                 * of found clusters and mark it as non-free.
                 */
                lifo[found] = cl;
                *clst = (found == 0) ?
                    host2uint16_t_le(FAT_CLST_LAST1) :
                    host2uint16_t_le(lifo[found - 1]);
                blk->dirty = true;  /* need to sync block */
                if (++found == nclsts) {
                    /* we are almost done */
                    block_put(blk);
                    /* update the shadow copies of FAT */
                    fat_alloc_shadow_clusters(bs,
                        dev_handle, lifo, nclsts);
                    *mcl = lifo[found - 1];
                    *lcl = lifo[0];
                    free(lifo);
                    futex_up(&fat_alloc_lock);
                    return EOK;
                }
            }
        }
        block_put(blk);
    }
    futex_up(&fat_alloc_lock);
 
    /*
     * We could not find enough clusters. Now we need to free the clusters
     * we have allocated so far.
     */
    while (found--) {
        fat_mark_cluster(bs, dev_handle, FAT1, lifo[found],
            FAT_CLST_RES0);
    }
   
    free(lifo);
    return ENOSPC;
}
 
void fat_append_clusters(fat_bs_t *bs, fat_node_t *nodep, fat_cluster_t mcl)
{
    dev_handle_t dev_handle = nodep->idx->dev_handle;
    fat_cluster_t lcl;
    uint8_t fatno;
 
    if (_fat_blcks_get(bs, dev_handle, nodep->firstc, &lcl) == 0) {
        nodep->firstc = host2uint16_t_le(mcl);
        nodep->dirty = true;        /* need to sync node */
        return;
    }
 
    for (fatno = FAT1; fatno < bs->fatcnt; fatno++)
        fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl);
}
 
/**
 * @}
 */
 

Rev 3516	Rev 3517
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 <errno.h>	43	#include <errno.h>
44	#include <byteorder.h>	44	#include <byteorder.h>
45	#include <align.h>	45	#include <align.h>
46	#include <assert.h>	46	#include <assert.h>
-		47	#include <futex.h>
-		48
-		49	/**
-		50	* The fat_alloc_lock futex protects all copies of the File Allocation Table
-		51	* during allocation of clusters. The lock does not have to be held durring
-		52	* deallocation of clusters.
-		53	*/
-		54	static futex_t fat_alloc_lock = FUTEX_INITIALIZER;
47		55
48	block_t *	56	block_t *
49	_fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,	57	_fat_block_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
50	off_t offset)	58	off_t offset)
51	{	59	{
52	block_t *b;	60	block_t *b;
53	unsigned bps;	61	unsigned bps;
54	unsigned spc;	62	unsigned spc;
55	unsigned rscnt; /* block address of the first FAT */	63	unsigned rscnt; /* block address of the first FAT */
56	unsigned fatcnt;	64	unsigned fatcnt;
57	unsigned rde;	65	unsigned rde;
58	unsigned rds; /* root directory size */	66	unsigned rds; /* root directory size */
59	unsigned sf;	67	unsigned sf;
60	unsigned ssa; /* size of the system area */	68	unsigned ssa; /* size of the system area */
61	unsigned clusters;	69	unsigned clusters;
62	fat_cluster_t clst = firstc;	70	fat_cluster_t clst = firstc;
63	unsigned i;	71	unsigned i;
64		72
65	bps = uint16_t_le2host(bs->bps);	73	bps = uint16_t_le2host(bs->bps);
66	spc = bs->spc;	74	spc = bs->spc;
67	rscnt = uint16_t_le2host(bs->rscnt);	75	rscnt = uint16_t_le2host(bs->rscnt);
68	fatcnt = bs->fatcnt;	76	fatcnt = bs->fatcnt;
69	rde = uint16_t_le2host(bs->root_ent_max);	77	rde = uint16_t_le2host(bs->root_ent_max);
70	sf = uint16_t_le2host(bs->sec_per_fat);	78	sf = uint16_t_le2host(bs->sec_per_fat);
71		79
72	rds = (sizeof(fat_dentry_t) * rde) / bps;	80	rds = (sizeof(fat_dentry_t) * rde) / bps;
73	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);	81	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
74	ssa = rscnt + fatcnt * sf + rds;	82	ssa = rscnt + fatcnt * sf + rds;
75		83
76	if (firstc == FAT_CLST_ROOT) {	84	if (firstc == FAT_CLST_ROOT) {
77	/* root directory special case */	85	/* root directory special case */
78	assert(offset < rds);	86	assert(offset < rds);
79	b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);	87	b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
80	return b;	88	return b;
81	}	89	}
82		90
83	clusters = offset / spc;	91	clusters = offset / spc;
84	for (i = 0; i < clusters; i++) {	92	for (i = 0; i < clusters; i++) {
85	unsigned fsec; /* sector offset relative to FAT1 */	93	unsigned fsec; /* sector offset relative to FAT1 */
86	unsigned fidx; /* FAT1 entry index */	94	unsigned fidx; /* FAT1 entry index */
87		95
88	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);	96	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
89	fsec = (clst * sizeof(fat_cluster_t)) / bps;	97	fsec = (clst * sizeof(fat_cluster_t)) / bps;
90	fidx = clst % (bps / sizeof(fat_cluster_t));	98	fidx = clst % (bps / sizeof(fat_cluster_t));
91	/* read FAT1 */	99	/* read FAT1 */
92	b = block_get(dev_handle, rscnt + fsec, bps);	100	b = block_get(dev_handle, rscnt + fsec, bps);
93	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	101	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
94	assert(clst != FAT_CLST_BAD);	102	assert(clst != FAT_CLST_BAD);
95	assert(clst < FAT_CLST_LAST1);	103	assert(clst < FAT_CLST_LAST1);
96	block_put(b);	104	block_put(b);
97	}	105	}
98		106
99	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +	107	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
100	offset % spc, bps);	108	offset % spc, bps);
101		109
102	return b;	110	return b;
103	}	111	}
104		112
105	/** Return number of blocks allocated to a file.	113	/** Return number of blocks allocated to a file.
106	*	114	*
107	* @param bs Buffer holding the boot sector for the file.	115	* @param bs Buffer holding the boot sector for the file.
108	* @param dev_handle Device handle of the device with the file.	116	* @param dev_handle Device handle of the device with the file.
109	* @param firstc First cluster of the file.	117	* @param firstc First cluster of the file.
110	* @param lastc If non-NULL, output argument holding the	118	* @param lastc If non-NULL, output argument holding the
111	* last cluster.	119	* last cluster.
112	*	120	*
113	* @return Number of blocks allocated to the file.	121	* @return Number of blocks allocated to the file.
114	*/	122	*/
115	uint16_t	123	uint16_t
116	_fat_blcks_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,	124	_fat_blcks_get(fat_bs_t *bs, dev_handle_t dev_handle, fat_cluster_t firstc,
117	fat_cluster_t *lastc)	125	fat_cluster_t *lastc)
118	{	126	{
119	block_t *b;	127	block_t *b;
120	unsigned bps;	128	unsigned bps;
121	unsigned spc;	129	unsigned spc;
122	unsigned rscnt; /* block address of the first FAT */	130	unsigned rscnt; /* block address of the first FAT */
123	unsigned clusters = 0;	131	unsigned clusters = 0;
124	fat_cluster_t clst = firstc;	132	fat_cluster_t clst = firstc;
125		133
126	bps = uint16_t_le2host(bs->bps);	134	bps = uint16_t_le2host(bs->bps);
127	spc = bs->spc;	135	spc = bs->spc;
128	rscnt = uint16_t_le2host(bs->rscnt);	136	rscnt = uint16_t_le2host(bs->rscnt);
129		137
130	if (firstc == FAT_CLST_RES0) {	138	if (firstc == FAT_CLST_RES0) {
131	/* No space allocated to the file. */	139	/* No space allocated to the file. */
132	if (lastc)	140	if (lastc)
133	*lastc = firstc;	141	*lastc = firstc;
134	return 0;	142	return 0;
135	}	143	}
136		144
137	while (clst < FAT_CLST_LAST1) {	145	while (clst < FAT_CLST_LAST1) {
138	unsigned fsec; /* sector offset relative to FAT1 */	146	unsigned fsec; /* sector offset relative to FAT1 */
139	unsigned fidx; /* FAT1 entry index */	147	unsigned fidx; /* FAT1 entry index */
140		148
141	assert(clst >= FAT_CLST_FIRST);	149	assert(clst >= FAT_CLST_FIRST);
142	if (lastc)	150	if (lastc)
143	lastc = clst; / remember the last cluster */	151	lastc = clst; / remember the last cluster */
144	fsec = (clst * sizeof(fat_cluster_t)) / bps;	152	fsec = (clst * sizeof(fat_cluster_t)) / bps;
145	fidx = clst % (bps / sizeof(fat_cluster_t));	153	fidx = clst % (bps / sizeof(fat_cluster_t));
146	/* read FAT1 */	154	/* read FAT1 */
147	b = block_get(dev_handle, rscnt + fsec, bps);	155	b = block_get(dev_handle, rscnt + fsec, bps);
148	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	156	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
149	assert(clst != FAT_CLST_BAD);	157	assert(clst != FAT_CLST_BAD);
150	block_put(b);	158	block_put(b);
151	clusters++;	159	clusters++;
152	}	160	}
153		161
154	if (lastc)	162	if (lastc)
155	*lastc = clst;	163	*lastc = clst;
156	return clusters * spc;	164	return clusters * spc;
157	}	165	}
158		166
159	/** Fill the gap between EOF and a new file position.	167	/** Fill the gap between EOF and a new file position.
160	*	168	*
161	* @param bs Buffer holding the boot sector for nodep.	169	* @param bs Buffer holding the boot sector for nodep.
162	* @param nodep FAT node with the gap.	170	* @param nodep FAT node with the gap.
163	* @param mcl First cluster in an independent cluster chain that will	171	* @param mcl First cluster in an independent cluster chain that will
164	* be later appended to the end of the node's own cluster	172	* be later appended to the end of the node's own cluster
165	* chain. If pos is still in the last allocated cluster,	173	* chain. If pos is still in the last allocated cluster,
166	* this argument is ignored.	174	* this argument is ignored.
167	* @param pos Position in the last node block.	175	* @param pos Position in the last node block.
168	*/	176	*/
169	void fat_fill_gap(fat_bs_t bs, fat_node_t nodep, fat_cluster_t mcl, off_t pos)	177	void fat_fill_gap(fat_bs_t bs, fat_node_t nodep, fat_cluster_t mcl, off_t pos)
170	{	178	{
171	uint16_t bps;	179	uint16_t bps;
172	unsigned spc;	180	unsigned spc;
173	block_t *b;	181	block_t *b;
174	off_t o, boundary;	182	off_t o, boundary;
175		183
176	bps = uint16_t_le2host(bs->bps);	184	bps = uint16_t_le2host(bs->bps);
177	spc = bs->spc;	185	spc = bs->spc;
178		186
179	boundary = ROUND_UP(nodep->size, bps * spc);	187	boundary = ROUND_UP(nodep->size, bps * spc);
180		188
181	/* zero out already allocated space */	189	/* zero out already allocated space */
182	for (o = nodep->size - 1; o < pos && o < boundary;	190	for (o = nodep->size - 1; o < pos && o < boundary;
183	o = ALIGN_DOWN(o + bps, bps)) {	191	o = ALIGN_DOWN(o + bps, bps)) {
184	b = fat_block_get(bs, nodep, o / bps);	192	b = fat_block_get(bs, nodep, o / bps);
185	memset(b->data + o % bps, 0, bps - o % bps);	193	memset(b->data + o % bps, 0, bps - o % bps);
186	b->dirty = true; /* need to sync node */	194	b->dirty = true; /* need to sync node */
187	block_put(b);	195	block_put(b);
188	}	196	}
189		197
190	if (o >= pos)	198	if (o >= pos)
191	return;	199	return;
192		200
193	/* zero out the initial part of the new cluster chain */	201	/* zero out the initial part of the new cluster chain */
194	for (o = boundary; o < pos; o += bps) {	202	for (o = boundary; o < pos; o += bps) {
195	b = _fat_block_get(bs, nodep->idx->dev_handle, mcl,	203	b = _fat_block_get(bs, nodep->idx->dev_handle, mcl,
196	(o - boundary) / bps);	204	(o - boundary) / bps);
197	memset(b->data, 0, min(bps, pos - o));	205	memset(b->data, 0, min(bps, pos - o));
198	b->dirty = true; /* need to sync node */	206	b->dirty = true; /* need to sync node */
199	block_put(b);	207	block_put(b);
200	}	208	}
201	}	209	}
202		210
203	void	211	void
204	fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,	212	fat_mark_cluster(fat_bs_t *bs, dev_handle_t dev_handle, unsigned fatno,
205	fat_cluster_t clst, fat_cluster_t value)	213	fat_cluster_t clst, fat_cluster_t value)
206	{	214	{
207	block_t *b;	215	block_t *b;
208	uint16_t bps;	216	uint16_t bps;
209	uint16_t rscnt;	217	uint16_t rscnt;
210	uint16_t sf;	218	uint16_t sf;
211	fat_cluster_t *cp;	219	fat_cluster_t *cp;
212		220
213	bps = uint16_t_le2host(bs->bps);	221	bps = uint16_t_le2host(bs->bps);
214	rscnt = uint16_t_le2host(bs->rscnt);	222	rscnt = uint16_t_le2host(bs->rscnt);
215	sf = uint16_t_le2host(bs->sec_per_fat);	223	sf = uint16_t_le2host(bs->sec_per_fat);
216		224
217	assert(fatno < bs->fatcnt);	225	assert(fatno < bs->fatcnt);
218	b = block_get(dev_handle, rscnt + sf * fatno +	226	b = block_get(dev_handle, rscnt + sf * fatno +
219	(clst * sizeof(fat_cluster_t)) / bps, bps);	227	(clst * sizeof(fat_cluster_t)) / bps, bps);
220	cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));	228	cp = (fat_cluster_t *)b->data + clst % (bps / sizeof(fat_cluster_t));
221	*cp = host2uint16_t_le(value);	229	*cp = host2uint16_t_le(value);
222	b->dirty = true; /* need to sync block */	230	b->dirty = true; /* need to sync block */
223	block_put(b);	231	block_put(b);
224	}	232	}
225		233
226	void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,	234	void fat_alloc_shadow_clusters(fat_bs_t *bs, dev_handle_t dev_handle,
227	fat_cluster_t *lifo, unsigned nclsts)	235	fat_cluster_t *lifo, unsigned nclsts)
228	{	236	{
229	uint8_t fatno;	237	uint8_t fatno;
230	unsigned c;	238	unsigned c;
231		239
232	for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) {	240	for (fatno = FAT1 + 1; fatno < bs->fatcnt; fatno++) {
233	for (c = 0; c < nclsts; c++) {	241	for (c = 0; c < nclsts; c++) {
234	fat_mark_cluster(bs, dev_handle, fatno, lifo[c],	242	fat_mark_cluster(bs, dev_handle, fatno, lifo[c],
235	c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]);	243	c == 0 ? FAT_CLST_LAST1 : lifo[c - 1]);
236	}	244	}
237	}	245	}
238	}	246	}
239		247
240	int	248	int
241	fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,	249	fat_alloc_clusters(fat_bs_t *bs, dev_handle_t dev_handle, unsigned nclsts,
242	fat_cluster_t mcl, fat_cluster_t lcl)	250	fat_cluster_t mcl, fat_cluster_t lcl)
243	{	251	{
244	uint16_t bps;	252	uint16_t bps;
245	uint16_t rscnt;	253	uint16_t rscnt;
246	uint16_t sf;	254	uint16_t sf;
247	block_t *blk;	255	block_t *blk;
248	fat_cluster_t lifo; / stack for storing free cluster numbers */	256	fat_cluster_t lifo; / stack for storing free cluster numbers */
249	unsigned found = 0; /* top of the free cluster number stack */	257	unsigned found = 0; /* top of the free cluster number stack */
250	unsigned b, c, cl;	258	unsigned b, c, cl;
251		259
252	lifo = (fat_cluster_t ) malloc(nclsts sizeof(fat_cluster_t));	260	lifo = (fat_cluster_t ) malloc(nclsts sizeof(fat_cluster_t));
253	if (lifo)	261	if (lifo)
254	return ENOMEM;	262	return ENOMEM;
255		263
256	bps = uint16_t_le2host(bs->bps);	264	bps = uint16_t_le2host(bs->bps);
257	rscnt = uint16_t_le2host(bs->rscnt);	265	rscnt = uint16_t_le2host(bs->rscnt);
258	sf = uint16_t_le2host(bs->sec_per_fat);	266	sf = uint16_t_le2host(bs->sec_per_fat);
259		267
260	/*	268	/*
261	* Search FAT1 for unused clusters.	269	* Search FAT1 for unused clusters.
262	*/	270	*/
-		271	futex_down(&fat_alloc_lock);
263	for (b = 0, cl = 0; b < sf; blk++) {	272	for (b = 0, cl = 0; b < sf; blk++) {
264	blk = block_get(dev_handle, rscnt + b, bps);	273	blk = block_get(dev_handle, rscnt + b, bps);
265	for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {	274	for (c = 0; c < bps / sizeof(fat_cluster_t); c++, cl++) {
266	fat_cluster_t clst = (fat_cluster_t )blk->data + c;	275	fat_cluster_t clst = (fat_cluster_t )blk->data + c;
267	if (uint16_t_le2host(*clst) == FAT_CLST_RES0) {	276	if (uint16_t_le2host(*clst) == FAT_CLST_RES0) {
268	/*	277	/*
269	* The cluster is free. Put it into our stack	278	* The cluster is free. Put it into our stack
270	* of found clusters and mark it as non-free.	279	* of found clusters and mark it as non-free.
271	*/	280	*/
272	lifo[found] = cl;	281	lifo[found] = cl;
273	*clst = (found == 0) ?	282	*clst = (found == 0) ?
274	host2uint16_t_le(FAT_CLST_LAST1) :	283	host2uint16_t_le(FAT_CLST_LAST1) :
275	host2uint16_t_le(lifo[found - 1]);	284	host2uint16_t_le(lifo[found - 1]);
276	blk->dirty = true; /* need to sync block */	285	blk->dirty = true; /* need to sync block */
277	if (++found == nclsts) {	286	if (++found == nclsts) {
278	/* we are almost done */	287	/* we are almost done */
279	block_put(blk);	288	block_put(blk);
280	/* update the shadow copies of FAT */	289	/* update the shadow copies of FAT */
281	fat_alloc_shadow_clusters(bs,	290	fat_alloc_shadow_clusters(bs,
282	dev_handle, lifo, nclsts);	291	dev_handle, lifo, nclsts);
283	*mcl = lifo[found - 1];	292	*mcl = lifo[found - 1];
284	*lcl = lifo[0];	293	*lcl = lifo[0];
285	free(lifo);	294	free(lifo);
-		295	futex_up(&fat_alloc_lock);
286	return EOK;	296	return EOK;
287	}	297	}
288	}	298	}
289	}	299	}
290	block_put(blk);	300	block_put(blk);
291	}	301	}
-		302	futex_up(&fat_alloc_lock);
292		303
293	/*	304	/*
294	* We could not find enough clusters. Now we need to free the clusters	305	* We could not find enough clusters. Now we need to free the clusters
295	* we have allocated so far.	306	* we have allocated so far.
296	*/	307	*/
297	while (found--) {	308	while (found--) {
298	fat_mark_cluster(bs, dev_handle, FAT1, lifo[found],	309	fat_mark_cluster(bs, dev_handle, FAT1, lifo[found],
299	FAT_CLST_RES0);	310	FAT_CLST_RES0);
300	}	311	}
301		312
302	free(lifo);	313	free(lifo);
303	return ENOSPC;	314	return ENOSPC;
304	}	315	}
305		316
306	void fat_append_clusters(fat_bs_t bs, fat_node_t nodep, fat_cluster_t mcl)	317	void fat_append_clusters(fat_bs_t bs, fat_node_t nodep, fat_cluster_t mcl)
307	{	318	{
308	dev_handle_t dev_handle = nodep->idx->dev_handle;	319	dev_handle_t dev_handle = nodep->idx->dev_handle;
309	fat_cluster_t lcl;	320	fat_cluster_t lcl;
310	uint8_t fatno;	321	uint8_t fatno;
311		322
312	if (_fat_blcks_get(bs, dev_handle, nodep->firstc, &lcl) == 0) {	323	if (_fat_blcks_get(bs, dev_handle, nodep->firstc, &lcl) == 0) {
313	nodep->firstc = host2uint16_t_le(mcl);	324	nodep->firstc = host2uint16_t_le(mcl);
314	nodep->dirty = true; /* need to sync node */	325	nodep->dirty = true; /* need to sync node */
315	return;	326	return;
316	}	327	}
317		328
318	for (fatno = FAT1; fatno < bs->fatcnt; fatno++)	329	for (fatno = FAT1; fatno < bs->fatcnt; fatno++)
319	fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl);	330	fat_mark_cluster(bs, nodep->idx->dev_handle, fatno, lcl, mcl);
320	}	331	}
321		332
322	/**	333	/**
323	* @}	334	* @}
324	*/	335	*/
325		336

Subversion Repositories HelenOS

(root)/branches/dynload/uspace/srv/fs/fat/fat_fat.c @ 3674 – Rev 3516 → 3517