WebSVN – HelenOS – Diff – /branches/network/uspace/srv/fs/fat/fat_ops.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_ops.c
 * @brief   Implementation of VFS operations for the FAT file system server.
 */
 
#include "fat.h"
#include "../../vfs/vfs.h"
#include <libfs.h>
#include <ipc/ipc.h>
#include <async.h>
#include <errno.h>
#include <string.h>
#include <byteorder.h>
#include <libadt/hash_table.h>
#include <libadt/list.h>
#include <assert.h>
#include <futex.h>
 
#define BS_BLOCK        0
 
/** Futex protecting the list of cached free FAT nodes. */
static futex_t ffn_futex = FUTEX_INITIALIZER;
 
/** List of cached free FAT nodes. */
static LIST_INITIALIZE(ffn_head);
 
#define FAT_NAME_LEN        8
#define FAT_EXT_LEN     3
 
#define FAT_PAD         ' ' 
 
#define FAT_DENTRY_UNUSED   0x00
#define FAT_DENTRY_E5_ESC   0x05
#define FAT_DENTRY_DOT      0x2e
#define FAT_DENTRY_ERASED   0xe5
 
static void dentry_name_canonify(fat_dentry_t *d, char *buf)
{
    int i;
 
    for (i = 0; i < FAT_NAME_LEN; i++) {
        if (d->name[i] == FAT_PAD) {
            buf++;
            break;
        }
        if (d->name[i] == FAT_DENTRY_E5_ESC)
            *buf++ = 0xe5;
        else
            *buf++ = d->name[i];
    }
    if (d->ext[0] != FAT_PAD)
        *buf++ = '.';
    for (i = 0; i < FAT_EXT_LEN; i++) {
        if (d->ext[i] == FAT_PAD) {
            *buf = '\0';
            return;
        }
        if (d->ext[i] == FAT_DENTRY_E5_ESC)
            *buf++ = 0xe5;
        else
            *buf++ = d->ext[i];
    }
}
 
/* TODO move somewhere else */
typedef struct {
    void *data;
} block_t;
 
static block_t *block_get(dev_handle_t dev_handle, off_t offset)
{
    return NULL;    /* TODO */
}
 
static void block_put(block_t *block)
{
    /* TODO */
}
 
#define FAT_BS(b)       ((fat_bs_t *)((b)->data))
 
#define FAT_CLST_RES0   0x0000
#define FAT_CLST_RES1   0x0001
#define FAT_CLST_FIRST  0x0002
#define FAT_CLST_BAD    0xfff7
#define FAT_CLST_LAST1  0xfff8
#define FAT_CLST_LAST8  0xffff
 
/* internally used to mark root directory's parent */
#define FAT_CLST_ROOTPAR    FAT_CLST_RES0
/* internally used to mark root directory */
#define FAT_CLST_ROOT       FAT_CLST_RES1
 
#define fat_block_get(np, off) \
    _fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
 
static block_t *
_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
{
    block_t *bb;
    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;
 
    bb = block_get(dev_handle, BS_BLOCK);
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
    spc = FAT_BS(bb)->spc;
    rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
    fatcnt = FAT_BS(bb)->fatcnt;
    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
    sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
    block_put(bb);
 
    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);
        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);
        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);
 
    return b;
}
 
static void fat_node_initialize(fat_node_t *node)
{
    futex_initialize(&node->lock, 1);
    node->idx = NULL;
    node->type = 0;
    link_initialize(&node->ffn_link);
    node->size = 0;
    node->lnkcnt = 0;
    node->refcnt = 0;
    node->dirty = false;
}
 
static uint16_t fat_bps_get(dev_handle_t dev_handle)
{
    block_t *bb;
    uint16_t bps;
   
    bb = block_get(dev_handle, BS_BLOCK);
    assert(bb != NULL);
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
    block_put(bb);
 
    return bps;
}
 
typedef enum {
    FAT_DENTRY_SKIP,
    FAT_DENTRY_LAST,
    FAT_DENTRY_VALID
} fat_dentry_clsf_t;
 
static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
{
    if (d->attr & FAT_ATTR_VOLLABEL) {
        /* volume label entry */
        return FAT_DENTRY_SKIP;
    }
    if (d->name[0] == FAT_DENTRY_ERASED) {
        /* not-currently-used entry */
        return FAT_DENTRY_SKIP;
    }
    if (d->name[0] == FAT_DENTRY_UNUSED) {
        /* never used entry */
        return FAT_DENTRY_LAST;
    }
    if (d->name[0] == FAT_DENTRY_DOT) {
        /*
         * Most likely '.' or '..'.
         * It cannot occur in a regular file name.
         */
        return FAT_DENTRY_SKIP;
    }
    return FAT_DENTRY_VALID;
}
 
static void fat_node_sync(fat_node_t *node)
{
    /* TODO */
}
 
/** Internal version of fat_node_get().
 *
 * @param idxp      Locked index structure.
 */
static void *fat_node_get_core(fat_idx_t *idxp)
{
    block_t *b;
    fat_dentry_t *d;
    fat_node_t *nodep;
    unsigned bps;
    unsigned dps;
 
    if (idxp->nodep) {
        /*
         * We are lucky.
         * The node is already instantiated in memory.
         */
        futex_down(&idxp->nodep->lock);
        if (!idxp->nodep->refcnt++)
            list_remove(&nodep->ffn_link);
        futex_up(&idxp->nodep->lock);
        return idxp->nodep;
    }
 
    /*
     * We must instantiate the node from the file system.
     */
   
    assert(idxp->pfc);
 
    futex_down(&ffn_futex);
    if (!list_empty(&ffn_head)) {
        /* Try to use a cached free node structure. */
        fat_idx_t *idxp_tmp;
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
            goto skip_cache;
        idxp_tmp = nodep->idx;
        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
            futex_up(&nodep->lock);
            goto skip_cache;
        }
        list_remove(&nodep->ffn_link);
        futex_up(&ffn_futex);
        if (nodep->dirty)
            fat_node_sync(nodep);
        idxp_tmp->nodep = NULL;
        futex_up(&nodep->lock);
        futex_up(&idxp_tmp->lock);
    } else {
skip_cache:
        /* Try to allocate a new node structure. */
        futex_up(&ffn_futex);
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
        if (!nodep)
            return NULL;
    }
    fat_node_initialize(nodep);
 
    bps = fat_bps_get(idxp->dev_handle);
    dps = bps / sizeof(fat_dentry_t);
 
    /* Read the block that contains the dentry of interest. */
    b = _fat_block_get(idxp->dev_handle, idxp->pfc,
        (idxp->pdi * sizeof(fat_dentry_t)) / bps);
    assert(b);
 
    d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
    if (d->attr & FAT_ATTR_SUBDIR) {
        /*
         * The only directory which does not have this bit set is the
         * root directory itself. The root directory node is handled
         * and initialized elsewhere.
         */
        nodep->type = FAT_DIRECTORY;
    } else {
        nodep->type = FAT_FILE;
    }
    nodep->firstc = uint16_t_le2host(d->firstc);
    nodep->size = uint32_t_le2host(d->size);
    nodep->lnkcnt = 1;
    nodep->refcnt = 1;
 
    block_put(b);
 
    /* Link the idx structure with the node structure. */
    nodep->idx = idxp;
    idxp->nodep = nodep;
 
    return nodep;
}
 
/** Instantiate a FAT in-core node. */
static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
{
    void *node;
    fat_idx_t *idxp;
 
    idxp = fat_idx_get_by_index(dev_handle, index);
    if (!idxp)
        return NULL;
    /* idxp->lock held */
    node = fat_node_get_core(idxp);
    futex_up(&idxp->lock);
    return node;
}
 
static void fat_node_put(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
 
    futex_down(&nodep->lock);
    if (!--nodep->refcnt) {
        futex_down(&ffn_futex);
        list_append(&nodep->ffn_link, &ffn_head);
        futex_up(&ffn_futex);
    }
    futex_up(&nodep->lock);
}
 
static void *fat_create(int flags)
{
    return NULL;    /* not supported at the moment */
}
 
static int fat_destroy(void *node)
{
    return ENOTSUP; /* not supported at the moment */
}
 
static bool fat_link(void *prnt, void *chld, const char *name)
{
    return false;   /* not supported at the moment */
}
 
static int fat_unlink(void *prnt, void *chld)
{
    return ENOTSUP; /* not supported at the moment */
}
 
static void *fat_match(void *prnt, const char *component)
{
    fat_node_t *parentp = (fat_node_t *)prnt;
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
    unsigned i, j;
    unsigned bps;       /* bytes per sector */
    unsigned dps;       /* dentries per sector */
    unsigned blocks;
    fat_dentry_t *d;
    block_t *b;
 
    futex_down(&parentp->idx->lock);
    bps = fat_bps_get(parentp->idx->dev_handle);
    dps = bps / sizeof(fat_dentry_t);
    blocks = parentp->size / bps + (parentp->size % bps != 0);
    for (i = 0; i < blocks; i++) {
        unsigned dentries;
       
        b = fat_block_get(parentp, i);
        dentries = (i == blocks - 1) ?
            parentp->size % sizeof(fat_dentry_t) :
            dps;
        for (j = 0; j < dentries; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
                continue;
            case FAT_DENTRY_LAST:
                block_put(b);
                futex_up(&parentp->idx->lock);
                return NULL;
            default:
            case FAT_DENTRY_VALID:
                dentry_name_canonify(d, name);
                break;
            }
            if (strcmp(name, component) == 0) {
                /* hit */
                void *node;
                /*
                 * Assume tree hierarchy for locking.  We
                 * already have the parent and now we are going
                 * to lock the child.  Never lock in the oposite
                 * order.
                 */
                fat_idx_t *idx = fat_idx_get_by_pos(
                    parentp->idx->dev_handle, parentp->firstc,
                    i * dps + j);
                futex_up(&parentp->idx->lock);
                if (!idx) {
                    /*
                     * Can happen if memory is low or if we
                     * run out of 32-bit indices.
                     */
                    block_put(b);
                    return NULL;
                }
                node = fat_node_get_core(idx);
                futex_up(&idx->lock);
                block_put(b);
                return node;
            }
        }
        block_put(b);
    }
    futex_up(&parentp->idx->lock);
    return NULL;
}
 
static fs_index_t fat_index_get(void *node)
{
    fat_node_t *fnodep = (fat_node_t *)node;
    if (!fnodep)
        return 0;
    return fnodep->idx->index;
}
 
static size_t fat_size_get(void *node)
{
    return ((fat_node_t *)node)->size;
}
 
static unsigned fat_lnkcnt_get(void *node)
{
    return ((fat_node_t *)node)->lnkcnt;
}
 
static bool fat_has_children(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
    unsigned bps;
    unsigned dps;
    unsigned blocks;
    block_t *b;
    unsigned i, j;
 
    if (nodep->type != FAT_DIRECTORY)
        return false;
 
    futex_down(&nodep->idx->lock);
    bps = fat_bps_get(nodep->idx->dev_handle);
    dps = bps / sizeof(fat_dentry_t);
 
    blocks = nodep->size / bps + (nodep->size % bps != 0);
 
    for (i = 0; i < blocks; i++) {
        unsigned dentries;
        fat_dentry_t *d;
   
        b = fat_block_get(nodep, i);
        dentries = (i == blocks - 1) ?
            nodep->size % sizeof(fat_dentry_t) :
            dps;
        for (j = 0; j < dentries; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
                continue;
            case FAT_DENTRY_LAST:
                block_put(b);
                futex_up(&nodep->idx->lock);
                return false;
            default:
            case FAT_DENTRY_VALID:
                block_put(b);
                futex_up(&nodep->idx->lock);
                return true;
            }
            block_put(b);
            futex_up(&nodep->idx->lock);
            return true;
        }
        block_put(b);
    }
 
    futex_up(&nodep->idx->lock);
    return false;
}
 
static void *fat_root_get(dev_handle_t dev_handle)
{
    return fat_node_get(dev_handle, 0);
}
 
static char fat_plb_get_char(unsigned pos)
{
    return fat_reg.plb_ro[pos % PLB_SIZE];
}
 
static bool fat_is_directory(void *node)
{
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
}
 
static bool fat_is_file(void *node)
{
    return ((fat_node_t *)node)->type == FAT_FILE;
}
 
/** libfs operations */
libfs_ops_t fat_libfs_ops = {
    .match = fat_match,
    .node_get = fat_node_get,
    .node_put = fat_node_put,
    .create = fat_create,
    .destroy = fat_destroy,
    .link = fat_link,
    .unlink = fat_unlink,
    .index_get = fat_index_get,
    .size_get = fat_size_get,
    .lnkcnt_get = fat_lnkcnt_get,
    .has_children = fat_has_children,
    .root_get = fat_root_get,
    .plb_get_char = fat_plb_get_char,
    .is_directory = fat_is_directory,
    .is_file = fat_is_file
};
 
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
    block_t *bb;
    uint16_t rde;
    int rc;
 
    /* Read the number of root directory entries. */
    bb = block_get(dev_handle, BS_BLOCK);
    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
    block_put(bb);
 
    rc = fat_idx_init_by_dev_handle(dev_handle);
    if (rc != EOK) {
        ipc_answer_0(rid, rc);
        return;
    }
 
    /* Initialize the root node. */
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
    if (!rootp) {
        fat_idx_fini_by_dev_handle(dev_handle);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    fat_node_initialize(rootp);
 
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
    if (!ridxp) {
        free(rootp);
        fat_idx_fini_by_dev_handle(dev_handle);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    assert(ridxp->index == 0);
    /* ridxp->lock held */
 
    rootp->type = FAT_DIRECTORY;
    rootp->firstc = FAT_CLST_ROOT;
    rootp->refcnt = 1;
    rootp->size = rde * sizeof(fat_dentry_t);
    rootp->idx = ridxp;
    ridxp->nodep = rootp;
   
    futex_up(&ridxp->lock);
 
    ipc_answer_0(rid, EOK);
}
 
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
{
    ipc_answer_0(rid, ENOTSUP);
}
 
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
{
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
}
 
/**
 * @}
 */
 

Rev 3110	Rev 3119
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_ops.c	34	* @file fat_ops.c
35	* @brief Implementation of VFS operations for the FAT file system server.	35	* @brief Implementation of VFS operations for the FAT file system server.
36	*/	36	*/
37		37
38	#include "fat.h"	38	#include "fat.h"
39	#include "../../vfs/vfs.h"	39	#include "../../vfs/vfs.h"
40	#include <libfs.h>	40	#include <libfs.h>
41	#include <ipc/ipc.h>	41	#include <ipc/ipc.h>
42	#include <async.h>	42	#include <async.h>
43	#include <errno.h>	43	#include <errno.h>
44	#include <string.h>	44	#include <string.h>
45	#include <byteorder.h>	45	#include <byteorder.h>
46	#include <libadt/hash_table.h>	46	#include <libadt/hash_table.h>
47	#include <libadt/list.h>	47	#include <libadt/list.h>
48	#include <assert.h>	48	#include <assert.h>
49	#include <futex.h>	49	#include <futex.h>
50		50
51	#define BS_BLOCK 0	51	#define BS_BLOCK 0
52		52
53	/** Futex protecting the list of cached free FAT nodes. */	53	/** Futex protecting the list of cached free FAT nodes. */
54	static futex_t ffn_futex = FUTEX_INITIALIZER;	54	static futex_t ffn_futex = FUTEX_INITIALIZER;
55		55
56	/** List of cached free FAT nodes. */	56	/** List of cached free FAT nodes. */
57	static LIST_INITIALIZE(ffn_head);	57	static LIST_INITIALIZE(ffn_head);
58		58
59	#define FAT_NAME_LEN 8	59	#define FAT_NAME_LEN 8
60	#define FAT_EXT_LEN 3	60	#define FAT_EXT_LEN 3
61		61
62	#define FAT_PAD ' '	62	#define FAT_PAD ' '
63		63
64	#define FAT_DENTRY_UNUSED 0x00	64	#define FAT_DENTRY_UNUSED 0x00
65	#define FAT_DENTRY_E5_ESC 0x05	65	#define FAT_DENTRY_E5_ESC 0x05
66	#define FAT_DENTRY_DOT 0x2e	66	#define FAT_DENTRY_DOT 0x2e
67	#define FAT_DENTRY_ERASED 0xe5	67	#define FAT_DENTRY_ERASED 0xe5
68		68
69	static void dentry_name_canonify(fat_dentry_t d, char buf)	69	static void dentry_name_canonify(fat_dentry_t d, char buf)
70	{	70	{
71	int i;	71	int i;
72		72
73	for (i = 0; i < FAT_NAME_LEN; i++) {	73	for (i = 0; i < FAT_NAME_LEN; i++) {
74	if (d->name[i] == FAT_PAD) {	74	if (d->name[i] == FAT_PAD) {
75	buf++;	75	buf++;
76	break;	76	break;
77	}	77	}
78	if (d->name[i] == FAT_DENTRY_E5_ESC)	78	if (d->name[i] == FAT_DENTRY_E5_ESC)
79	*buf++ = 0xe5;	79	*buf++ = 0xe5;
80	else	80	else
81	*buf++ = d->name[i];	81	*buf++ = d->name[i];
82	}	82	}
83	if (d->ext[0] != FAT_PAD)	83	if (d->ext[0] != FAT_PAD)
84	*buf++ = '.';	84	*buf++ = '.';
85	for (i = 0; i < FAT_EXT_LEN; i++) {	85	for (i = 0; i < FAT_EXT_LEN; i++) {
86	if (d->ext[i] == FAT_PAD) {	86	if (d->ext[i] == FAT_PAD) {
87	*buf = '\0';	87	*buf = '\0';
88	return;	88	return;
89	}	89	}
90	if (d->ext[i] == FAT_DENTRY_E5_ESC)	90	if (d->ext[i] == FAT_DENTRY_E5_ESC)
91	*buf++ = 0xe5;	91	*buf++ = 0xe5;
92	else	92	else
93	*buf++ = d->ext[i];	93	*buf++ = d->ext[i];
94	}	94	}
95	}	95	}
96		96
97	/* TODO move somewhere else */	97	/* TODO move somewhere else */
98	typedef struct {	98	typedef struct {
99	void *data;	99	void *data;
100	} block_t;	100	} block_t;
101		101
102	static block_t *block_get(dev_handle_t dev_handle, off_t offset)	102	static block_t *block_get(dev_handle_t dev_handle, off_t offset)
103	{	103	{
104	return NULL; /* TODO */	104	return NULL; /* TODO */
105	}	105	}
106		106
107	static void block_put(block_t *block)	107	static void block_put(block_t *block)
108	{	108	{
109	/* TODO */	109	/* TODO */
110	}	110	}
111		111
112	#define FAT_BS(b) ((fat_bs_t *)((b)->data))	112	#define FAT_BS(b) ((fat_bs_t *)((b)->data))
113		113
114	#define FAT_CLST_RES0 0x0000	114	#define FAT_CLST_RES0 0x0000
115	#define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */	115	#define FAT_CLST_RES1 0x0001
116	#define FAT_CLST_FIRST 0x0002	116	#define FAT_CLST_FIRST 0x0002
117	#define FAT_CLST_BAD 0xfff7	117	#define FAT_CLST_BAD 0xfff7
118	#define FAT_CLST_LAST1 0xfff8	118	#define FAT_CLST_LAST1 0xfff8
119	#define FAT_CLST_LAST8 0xffff	119	#define FAT_CLST_LAST8 0xffff
120		120
-		121	/* internally used to mark root directory's parent */
-		122	#define FAT_CLST_ROOTPAR FAT_CLST_RES0
-		123	/* internally used to mark root directory */
-		124	#define FAT_CLST_ROOT FAT_CLST_RES1
-		125
121	#define fat_block_get(np, off) \	126	#define fat_block_get(np, off) \
122	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))	127	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
123		128
124	static block_t *	129	static block_t *
125	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)	130	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
126	{	131	{
127	block_t *bb;	132	block_t *bb;
128	block_t *b;	133	block_t *b;
129	unsigned bps;	134	unsigned bps;
130	unsigned spc;	135	unsigned spc;
131	unsigned rscnt; /* block address of the first FAT */	136	unsigned rscnt; /* block address of the first FAT */
132	unsigned fatcnt;	137	unsigned fatcnt;
133	unsigned rde;	138	unsigned rde;
134	unsigned rds; /* root directory size */	139	unsigned rds; /* root directory size */
135	unsigned sf;	140	unsigned sf;
136	unsigned ssa; /* size of the system area */	141	unsigned ssa; /* size of the system area */
137	unsigned clusters;	142	unsigned clusters;
138	fat_cluster_t clst = firstc;	143	fat_cluster_t clst = firstc;
139	unsigned i;	144	unsigned i;
140		145
141	bb = block_get(dev_handle, BS_BLOCK);	146	bb = block_get(dev_handle, BS_BLOCK);
142	bps = uint16_t_le2host(FAT_BS(bb)->bps);	147	bps = uint16_t_le2host(FAT_BS(bb)->bps);
143	spc = FAT_BS(bb)->spc;	148	spc = FAT_BS(bb)->spc;
144	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);	149	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
145	fatcnt = FAT_BS(bb)->fatcnt;	150	fatcnt = FAT_BS(bb)->fatcnt;
146	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);	151	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
147	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);	152	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
148	block_put(bb);	153	block_put(bb);
149		154
150	rds = (sizeof(fat_dentry_t) * rde) / bps;	155	rds = (sizeof(fat_dentry_t) * rde) / bps;
151	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);	156	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
152	ssa = rscnt + fatcnt * sf + rds;	157	ssa = rscnt + fatcnt * sf + rds;
153		158
154	if (firstc == FAT_CLST_RES1) {	159	if (firstc == FAT_CLST_ROOT) {
155	/* root directory special case */	160	/* root directory special case */
156	assert(offset < rds);	161	assert(offset < rds);
157	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);	162	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
158	return b;	163	return b;
159	}	164	}
160		165
161	clusters = offset / spc;	166	clusters = offset / spc;
162	for (i = 0; i < clusters; i++) {	167	for (i = 0; i < clusters; i++) {
163	unsigned fsec; /* sector offset relative to FAT1 */	168	unsigned fsec; /* sector offset relative to FAT1 */
164	unsigned fidx; /* FAT1 entry index */	169	unsigned fidx; /* FAT1 entry index */
165		170
166	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);	171	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
167	fsec = (clst * sizeof(fat_cluster_t)) / bps;	172	fsec = (clst * sizeof(fat_cluster_t)) / bps;
168	fidx = clst % (bps / sizeof(fat_cluster_t));	173	fidx = clst % (bps / sizeof(fat_cluster_t));
169	/* read FAT1 */	174	/* read FAT1 */
170	b = block_get(dev_handle, rscnt + fsec);	175	b = block_get(dev_handle, rscnt + fsec);
171	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	176	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
172	assert(clst != FAT_CLST_BAD);	177	assert(clst != FAT_CLST_BAD);
173	assert(clst < FAT_CLST_LAST1);	178	assert(clst < FAT_CLST_LAST1);
174	block_put(b);	179	block_put(b);
175	}	180	}
176		181
177	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +	182	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
178	offset % spc);	183	offset % spc);
179		184
180	return b;	185	return b;
181	}	186	}
182		187
183	static void fat_node_initialize(fat_node_t *node)	188	static void fat_node_initialize(fat_node_t *node)
184	{	189	{
185	futex_initialize(&node->lock, 1);	190	futex_initialize(&node->lock, 1);
186	node->idx = NULL;	191	node->idx = NULL;
187	node->type = 0;	192	node->type = 0;
188	link_initialize(&node->ffn_link);	193	link_initialize(&node->ffn_link);
189	node->size = 0;	194	node->size = 0;
190	node->lnkcnt = 0;	195	node->lnkcnt = 0;
191	node->refcnt = 0;	196	node->refcnt = 0;
192	node->dirty = false;	197	node->dirty = false;
193	}	198	}
194		199
195	static uint16_t fat_bps_get(dev_handle_t dev_handle)	200	static uint16_t fat_bps_get(dev_handle_t dev_handle)
196	{	201	{
197	block_t *bb;	202	block_t *bb;
198	uint16_t bps;	203	uint16_t bps;
199		204
200	bb = block_get(dev_handle, BS_BLOCK);	205	bb = block_get(dev_handle, BS_BLOCK);
201	assert(bb != NULL);	206	assert(bb != NULL);
202	bps = uint16_t_le2host(FAT_BS(bb)->bps);	207	bps = uint16_t_le2host(FAT_BS(bb)->bps);
203	block_put(bb);	208	block_put(bb);
204		209
205	return bps;	210	return bps;
206	}	211	}
207		212
208	typedef enum {	213	typedef enum {
209	FAT_DENTRY_SKIP,	214	FAT_DENTRY_SKIP,
210	FAT_DENTRY_LAST,	215	FAT_DENTRY_LAST,
211	FAT_DENTRY_VALID	216	FAT_DENTRY_VALID
212	} fat_dentry_clsf_t;	217	} fat_dentry_clsf_t;
213		218
214	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)	219	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
215	{	220	{
216	if (d->attr & FAT_ATTR_VOLLABEL) {	221	if (d->attr & FAT_ATTR_VOLLABEL) {
217	/* volume label entry */	222	/* volume label entry */
218	return FAT_DENTRY_SKIP;	223	return FAT_DENTRY_SKIP;
219	}	224	}
220	if (d->name[0] == FAT_DENTRY_ERASED) {	225	if (d->name[0] == FAT_DENTRY_ERASED) {
221	/* not-currently-used entry */	226	/* not-currently-used entry */
222	return FAT_DENTRY_SKIP;	227	return FAT_DENTRY_SKIP;
223	}	228	}
224	if (d->name[0] == FAT_DENTRY_UNUSED) {	229	if (d->name[0] == FAT_DENTRY_UNUSED) {
225	/* never used entry */	230	/* never used entry */
226	return FAT_DENTRY_LAST;	231	return FAT_DENTRY_LAST;
227	}	232	}
228	if (d->name[0] == FAT_DENTRY_DOT) {	233	if (d->name[0] == FAT_DENTRY_DOT) {
229	/*	234	/*
230	* Most likely '.' or '..'.	235	* Most likely '.' or '..'.
231	* It cannot occur in a regular file name.	236	* It cannot occur in a regular file name.
232	*/	237	*/
233	return FAT_DENTRY_SKIP;	238	return FAT_DENTRY_SKIP;
234	}	239	}
235	return FAT_DENTRY_VALID;	240	return FAT_DENTRY_VALID;
236	}	241	}
237		242
238	static void fat_node_sync(fat_node_t *node)	243	static void fat_node_sync(fat_node_t *node)
239	{	244	{
240	/* TODO */	245	/* TODO */
241	}	246	}
242		247
243	/** Internal version of fat_node_get().	248	/** Internal version of fat_node_get().
244	*	249	*
245	* @param idxp Locked index structure.	250	* @param idxp Locked index structure.
246	*/	251	*/
247	static void fat_node_get_core(fat_idx_t idxp)	252	static void fat_node_get_core(fat_idx_t idxp)
248	{	253	{
249	block_t *b;	254	block_t *b;
250	fat_dentry_t *d;	255	fat_dentry_t *d;
251	fat_node_t *nodep;	256	fat_node_t *nodep;
252	unsigned bps;	257	unsigned bps;
253	unsigned dps;	258	unsigned dps;
254		259
255	if (idxp->nodep) {	260	if (idxp->nodep) {
256	/*	261	/*
257	* We are lucky.	262	* We are lucky.
258	* The node is already instantiated in memory.	263	* The node is already instantiated in memory.
259	*/	264	*/
260	futex_down(&idxp->nodep->lock);	265	futex_down(&idxp->nodep->lock);
261	if (!idxp->nodep->refcnt++)	266	if (!idxp->nodep->refcnt++)
262	list_remove(&nodep->ffn_link);	267	list_remove(&nodep->ffn_link);
263	futex_up(&idxp->nodep->lock);	268	futex_up(&idxp->nodep->lock);
264	return idxp->nodep;	269	return idxp->nodep;
265	}	270	}
266		271
267	/*	272	/*
268	* We must instantiate the node from the file system.	273	* We must instantiate the node from the file system.
269	*/	274	*/
270		275
271	assert(idxp->pfc);	276	assert(idxp->pfc);
272		277
273	futex_down(&ffn_futex);	278	futex_down(&ffn_futex);
274	if (!list_empty(&ffn_head)) {	279	if (!list_empty(&ffn_head)) {
275	/* Try to use a cached free node structure. */	280	/* Try to use a cached free node structure. */
276	fat_idx_t *idxp_tmp;	281	fat_idx_t *idxp_tmp;
277	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);	282	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
278	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)	283	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
279	goto skip_cache;	284	goto skip_cache;
280	idxp_tmp = nodep->idx;	285	idxp_tmp = nodep->idx;
281	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {	286	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
282	futex_up(&nodep->lock);	287	futex_up(&nodep->lock);
283	goto skip_cache;	288	goto skip_cache;
284	}	289	}
285	list_remove(&nodep->ffn_link);	290	list_remove(&nodep->ffn_link);
286	futex_up(&ffn_futex);	291	futex_up(&ffn_futex);
287	if (nodep->dirty)	292	if (nodep->dirty)
288	fat_node_sync(nodep);	293	fat_node_sync(nodep);
289	idxp_tmp->nodep = NULL;	294	idxp_tmp->nodep = NULL;
290	futex_up(&nodep->lock);	295	futex_up(&nodep->lock);
291	futex_up(&idxp_tmp->lock);	296	futex_up(&idxp_tmp->lock);
292	} else {	297	} else {
293	skip_cache:	298	skip_cache:
294	/* Try to allocate a new node structure. */	299	/* Try to allocate a new node structure. */
295	futex_up(&ffn_futex);	300	futex_up(&ffn_futex);
296	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	301	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
297	if (!nodep)	302	if (!nodep)
298	return NULL;	303	return NULL;
299	}	304	}
300	fat_node_initialize(nodep);	305	fat_node_initialize(nodep);
301		306
302	bps = fat_bps_get(idxp->dev_handle);	307	bps = fat_bps_get(idxp->dev_handle);
303	dps = bps / sizeof(fat_dentry_t);	308	dps = bps / sizeof(fat_dentry_t);
304		309
305	/* Read the block that contains the dentry of interest. */	310	/* Read the block that contains the dentry of interest. */
306	b = _fat_block_get(idxp->dev_handle, idxp->pfc,	311	b = _fat_block_get(idxp->dev_handle, idxp->pfc,
307	(idxp->pdi * sizeof(fat_dentry_t)) / bps);	312	(idxp->pdi * sizeof(fat_dentry_t)) / bps);
308	assert(b);	313	assert(b);
309		314
310	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);	315	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
311	if (d->attr & FAT_ATTR_SUBDIR) {	316	if (d->attr & FAT_ATTR_SUBDIR) {
312	/*	317	/*
313	* The only directory which does not have this bit set is the	318	* The only directory which does not have this bit set is the
314	* root directory itself. The root directory node is handled	319	* root directory itself. The root directory node is handled
315	* and initialized elsewhere.	320	* and initialized elsewhere.
316	*/	321	*/
317	nodep->type = FAT_DIRECTORY;	322	nodep->type = FAT_DIRECTORY;
318	} else {	323	} else {
319	nodep->type = FAT_FILE;	324	nodep->type = FAT_FILE;
320	}	325	}
321	nodep->firstc = uint16_t_le2host(d->firstc);	326	nodep->firstc = uint16_t_le2host(d->firstc);
322	nodep->size = uint32_t_le2host(d->size);	327	nodep->size = uint32_t_le2host(d->size);
323	nodep->lnkcnt = 1;	328	nodep->lnkcnt = 1;
324	nodep->refcnt = 1;	329	nodep->refcnt = 1;
325		330
326	block_put(b);	331	block_put(b);
327		332
328	/* Link the idx structure with the node structure. */	333	/* Link the idx structure with the node structure. */
329	nodep->idx = idxp;	334	nodep->idx = idxp;
330	idxp->nodep = nodep;	335	idxp->nodep = nodep;
331		336
332	return nodep;	337	return nodep;
333	}	338	}
334		339
335	/** Instantiate a FAT in-core node. */	340	/** Instantiate a FAT in-core node. */
336	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)	341	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
337	{	342	{
338	void *node;	343	void *node;
339	fat_idx_t *idxp;	344	fat_idx_t *idxp;
340		345
341	idxp = fat_idx_get_by_index(dev_handle, index);	346	idxp = fat_idx_get_by_index(dev_handle, index);
342	if (!idxp)	347	if (!idxp)
343	return NULL;	348	return NULL;
344	/* idxp->lock held */	349	/* idxp->lock held */
345	node = fat_node_get_core(idxp);	350	node = fat_node_get_core(idxp);
346	futex_up(&idxp->lock);	351	futex_up(&idxp->lock);
347	return node;	352	return node;
348	}	353	}
349		354
350	static void fat_node_put(void *node)	355	static void fat_node_put(void *node)
351	{	356	{
352	fat_node_t nodep = (fat_node_t )node;	357	fat_node_t nodep = (fat_node_t )node;
353		358
354	futex_down(&nodep->lock);	359	futex_down(&nodep->lock);
355	if (!--nodep->refcnt) {	360	if (!--nodep->refcnt) {
356	futex_down(&ffn_futex);	361	futex_down(&ffn_futex);
357	list_append(&nodep->ffn_link, &ffn_head);	362	list_append(&nodep->ffn_link, &ffn_head);
358	futex_up(&ffn_futex);	363	futex_up(&ffn_futex);
359	}	364	}
360	futex_up(&nodep->lock);	365	futex_up(&nodep->lock);
361	}	366	}
362		367
363	static void *fat_create(int flags)	368	static void *fat_create(int flags)
364	{	369	{
365	return NULL; /* not supported at the moment */	370	return NULL; /* not supported at the moment */
366	}	371	}
367		372
368	static int fat_destroy(void *node)	373	static int fat_destroy(void *node)
369	{	374	{
370	return ENOTSUP; /* not supported at the moment */	375	return ENOTSUP; /* not supported at the moment */
371	}	376	}
372		377
373	static bool fat_link(void prnt, void chld, const char *name)	378	static bool fat_link(void prnt, void chld, const char *name)
374	{	379	{
375	return false; /* not supported at the moment */	380	return false; /* not supported at the moment */
376	}	381	}
377		382
378	static int fat_unlink(void prnt, void chld)	383	static int fat_unlink(void prnt, void chld)
379	{	384	{
380	return ENOTSUP; /* not supported at the moment */	385	return ENOTSUP; /* not supported at the moment */
381	}	386	}
382		387
383	static void fat_match(void prnt, const char *component)	388	static void fat_match(void prnt, const char *component)
384	{	389	{
385	fat_node_t parentp = (fat_node_t )prnt;	390	fat_node_t parentp = (fat_node_t )prnt;
386	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	391	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
387	unsigned i, j;	392	unsigned i, j;
388	unsigned bps; /* bytes per sector */	393	unsigned bps; /* bytes per sector */
389	unsigned dps; /* dentries per sector */	394	unsigned dps; /* dentries per sector */
390	unsigned blocks;	395	unsigned blocks;
391	fat_dentry_t *d;	396	fat_dentry_t *d;
392	block_t *b;	397	block_t *b;
393		398
394	futex_down(&parentp->idx->lock);	399	futex_down(&parentp->idx->lock);
395	bps = fat_bps_get(parentp->idx->dev_handle);	400	bps = fat_bps_get(parentp->idx->dev_handle);
396	dps = bps / sizeof(fat_dentry_t);	401	dps = bps / sizeof(fat_dentry_t);
397	blocks = parentp->size / bps + (parentp->size % bps != 0);	402	blocks = parentp->size / bps + (parentp->size % bps != 0);
398	for (i = 0; i < blocks; i++) {	403	for (i = 0; i < blocks; i++) {
399	unsigned dentries;	404	unsigned dentries;
400		405
401	b = fat_block_get(parentp, i);	406	b = fat_block_get(parentp, i);
402	dentries = (i == blocks - 1) ?	407	dentries = (i == blocks - 1) ?
403	parentp->size % sizeof(fat_dentry_t) :	408	parentp->size % sizeof(fat_dentry_t) :
404	dps;	409	dps;
405	for (j = 0; j < dentries; j++) {	410	for (j = 0; j < dentries; j++) {
406	d = ((fat_dentry_t *)b->data) + j;	411	d = ((fat_dentry_t *)b->data) + j;
407	switch (fat_classify_dentry(d)) {	412	switch (fat_classify_dentry(d)) {
408	case FAT_DENTRY_SKIP:	413	case FAT_DENTRY_SKIP:
409	continue;	414	continue;
410	case FAT_DENTRY_LAST:	415	case FAT_DENTRY_LAST:
411	block_put(b);	416	block_put(b);
412	futex_up(&parentp->idx->lock);	417	futex_up(&parentp->idx->lock);
413	return NULL;	418	return NULL;
414	default:	419	default:
415	case FAT_DENTRY_VALID:	420	case FAT_DENTRY_VALID:
416	dentry_name_canonify(d, name);	421	dentry_name_canonify(d, name);
417	break;	422	break;
418	}	423	}
419	if (strcmp(name, component) == 0) {	424	if (strcmp(name, component) == 0) {
420	/* hit */	425	/* hit */
421	void *node;	426	void *node;
422	/*	427	/*
423	* Assume tree hierarchy for locking. We	428	* Assume tree hierarchy for locking. We
424	* already have the parent and now we are going	429	* already have the parent and now we are going
425	* to lock the child. Never lock in the oposite	430	* to lock the child. Never lock in the oposite
426	* order.	431	* order.
427	*/	432	*/
428	fat_idx_t *idx = fat_idx_get_by_pos(	433	fat_idx_t *idx = fat_idx_get_by_pos(
429	parentp->idx->dev_handle, parentp->firstc,	434	parentp->idx->dev_handle, parentp->firstc,
430	i * dps + j);	435	i * dps + j);
431	futex_up(&parentp->idx->lock);	436	futex_up(&parentp->idx->lock);
432	if (!idx) {	437	if (!idx) {
433	/*	438	/*
434	* Can happen if memory is low or if we	439	* Can happen if memory is low or if we
435	* run out of 32-bit indices.	440	* run out of 32-bit indices.
436	*/	441	*/
437	block_put(b);	442	block_put(b);
438	return NULL;	443	return NULL;
439	}	444	}
440	node = fat_node_get_core(idx);	445	node = fat_node_get_core(idx);
441	futex_up(&idx->lock);	446	futex_up(&idx->lock);
442	block_put(b);	447	block_put(b);
443	return node;	448	return node;
444	}	449	}
445	}	450	}
446	block_put(b);	451	block_put(b);
447	}	452	}
448	futex_up(&parentp->idx->lock);	453	futex_up(&parentp->idx->lock);
449	return NULL;	454	return NULL;
450	}	455	}
451		456
452	static fs_index_t fat_index_get(void *node)	457	static fs_index_t fat_index_get(void *node)
453	{	458	{
454	fat_node_t fnodep = (fat_node_t )node;	459	fat_node_t fnodep = (fat_node_t )node;
455	if (!fnodep)	460	if (!fnodep)
456	return 0;	461	return 0;
457	return fnodep->idx->index;	462	return fnodep->idx->index;
458	}	463	}
459		464
460	static size_t fat_size_get(void *node)	465	static size_t fat_size_get(void *node)
461	{	466	{
462	return ((fat_node_t *)node)->size;	467	return ((fat_node_t *)node)->size;
463	}	468	}
464		469
465	static unsigned fat_lnkcnt_get(void *node)	470	static unsigned fat_lnkcnt_get(void *node)
466	{	471	{
467	return ((fat_node_t *)node)->lnkcnt;	472	return ((fat_node_t *)node)->lnkcnt;
468	}	473	}
469		474
470	static bool fat_has_children(void *node)	475	static bool fat_has_children(void *node)
471	{	476	{
472	fat_node_t nodep = (fat_node_t )node;	477	fat_node_t nodep = (fat_node_t )node;
473	unsigned bps;	478	unsigned bps;
474	unsigned dps;	479	unsigned dps;
475	unsigned blocks;	480	unsigned blocks;
476	block_t *b;	481	block_t *b;
477	unsigned i, j;	482	unsigned i, j;
478		483
479	if (nodep->type != FAT_DIRECTORY)	484	if (nodep->type != FAT_DIRECTORY)
480	return false;	485	return false;
481		486
482	futex_down(&nodep->idx->lock);	487	futex_down(&nodep->idx->lock);
483	bps = fat_bps_get(nodep->idx->dev_handle);	488	bps = fat_bps_get(nodep->idx->dev_handle);
484	dps = bps / sizeof(fat_dentry_t);	489	dps = bps / sizeof(fat_dentry_t);
485		490
486	blocks = nodep->size / bps + (nodep->size % bps != 0);	491	blocks = nodep->size / bps + (nodep->size % bps != 0);
487		492
488	for (i = 0; i < blocks; i++) {	493	for (i = 0; i < blocks; i++) {
489	unsigned dentries;	494	unsigned dentries;
490	fat_dentry_t *d;	495	fat_dentry_t *d;
491		496
492	b = fat_block_get(nodep, i);	497	b = fat_block_get(nodep, i);
493	dentries = (i == blocks - 1) ?	498	dentries = (i == blocks - 1) ?
494	nodep->size % sizeof(fat_dentry_t) :	499	nodep->size % sizeof(fat_dentry_t) :
495	dps;	500	dps;

Subversion Repositories HelenOS

(root)/branches/network/uspace/srv/fs/fat/fat_ops.c @ 4718 – Rev 3110 → 3119