WebSVN – HelenOS – Diff – /trunk/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 "fat_dentry.h"
#include "fat_fat.h"
#include "../../vfs/vfs.h"
#include <libfs.h>
#include <libblock.h>
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <ipc/devmap.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>
#include <sys/mman.h>
#include <align.h>
 
#define FAT_NODE(node)  ((node) ? (fat_node_t *) (node)->data : NULL)
#define FS_NODE(node)   ((node) ? (node)->bp : NULL)
 
/** 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);
 
static void fat_node_initialize(fat_node_t *node)
{
    futex_initialize(&node->lock, 1);
    node->bp = NULL;
    node->idx = NULL;
    node->type = 0;
    link_initialize(&node->ffn_link);
    node->size = 0;
    node->lnkcnt = 0;
    node->refcnt = 0;
    node->dirty = false;
}
 
static void fat_node_sync(fat_node_t *node)
{
    block_t *b;
    fat_bs_t *bs;
    fat_dentry_t *d;
    uint16_t bps;
    unsigned dps;
   
    assert(node->dirty);
 
    bs = block_bb_get(node->idx->dev_handle);
    bps = uint16_t_le2host(bs->bps);
    dps = bps / sizeof(fat_dentry_t);
   
    /* Read the block that contains the dentry of interest. */
    b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
        (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
 
    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
 
    d->firstc = host2uint16_t_le(node->firstc);
    if (node->type == FAT_FILE) {
        d->size = host2uint32_t_le(node->size);
    } else if (node->type == FAT_DIRECTORY) {
        d->attr = FAT_ATTR_SUBDIR;
    }
   
    /* TODO: update other fields? (e.g time fields) */
   
    b->dirty = true;        /* need to sync block */
    block_put(b);
}
 
static fat_node_t *fat_node_get_new(void)
{
    fs_node_t *fn;
    fat_node_t *nodep;
 
    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);
        fn = FS_NODE(nodep);
    } else {
skip_cache:
        /* Try to allocate a new node structure. */
        futex_up(&ffn_futex);
        fn = (fs_node_t *)malloc(sizeof(fs_node_t));
        if (!fn)
            return NULL;
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
        if (!nodep) {
            free(fn);
            return NULL;
        }
    }
    fat_node_initialize(nodep);
    fn->data = nodep;
    nodep->bp = fn;
   
    return nodep;
}
 
/** Internal version of fat_node_get().
 *
 * @param idxp      Locked index structure.
 */
static fat_node_t *fat_node_get_core(fat_idx_t *idxp)
{
    block_t *b;
    fat_bs_t *bs;
    fat_dentry_t *d;
    fat_node_t *nodep = NULL;
    unsigned bps;
    unsigned spc;
    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(&idxp->nodep->ffn_link);
        futex_up(&idxp->nodep->lock);
        return idxp->nodep;
    }
 
    /*
     * We must instantiate the node from the file system.
     */
   
    assert(idxp->pfc);
 
    nodep = fat_node_get_new();
    if (!nodep)
        return NULL;
 
    bs = block_bb_get(idxp->dev_handle);
    bps = uint16_t_le2host(bs->bps);
    spc = bs->spc;
    dps = bps / sizeof(fat_dentry_t);
 
    /* Read the block that contains the dentry of interest. */
    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
    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;
        /*
         * Unfortunately, the 'size' field of the FAT dentry is not
         * defined for the directory entry type. We must determine the
         * size of the directory by walking the FAT.
         */
        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
            uint16_t_le2host(d->firstc));
    } else {
        nodep->type = FAT_FILE;
        nodep->size = uint32_t_le2host(d->size);
    }
    nodep->firstc = uint16_t_le2host(d->firstc);
    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;
}
 
/*
 * Forward declarations of FAT libfs operations.
 */
static fs_node_t *fat_node_get(dev_handle_t, fs_index_t);
static void fat_node_put(fs_node_t *);
static fs_node_t *fat_create_node(dev_handle_t, int);
static int fat_destroy_node(fs_node_t *);
static int fat_link(fs_node_t *, fs_node_t *, const char *);
static int fat_unlink(fs_node_t *, fs_node_t *);
static fs_node_t *fat_match(fs_node_t *, const char *);
static fs_index_t fat_index_get(fs_node_t *);
static size_t fat_size_get(fs_node_t *);
static unsigned fat_lnkcnt_get(fs_node_t *);
static bool fat_has_children(fs_node_t *);
static fs_node_t *fat_root_get(dev_handle_t);
static char fat_plb_get_char(unsigned);
static bool fat_is_directory(fs_node_t *);
static bool fat_is_file(fs_node_t *node);
 
/*
 * FAT libfs operations.
 */
 
/** Instantiate a FAT in-core node. */
fs_node_t *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
{
    fat_node_t *nodep;
    fat_idx_t *idxp;
 
    idxp = fat_idx_get_by_index(dev_handle, index);
    if (!idxp)
        return NULL;
    /* idxp->lock held */
    nodep = fat_node_get_core(idxp);
    futex_up(&idxp->lock);
    return FS_NODE(nodep);
}
 
void fat_node_put(fs_node_t *fn)
{
    fat_node_t *nodep = FAT_NODE(fn);
    bool destroy = false;
 
    futex_down(&nodep->lock);
    if (!--nodep->refcnt) {
        if (nodep->idx) {
            futex_down(&ffn_futex);
            list_append(&nodep->ffn_link, &ffn_head);
            futex_up(&ffn_futex);
        } else {
            /*
             * The node does not have any index structure associated
             * with itself. This can only mean that we are releasing
             * the node after a failed attempt to allocate the index
             * structure for it.
             */
            destroy = true;
        }
    }
    futex_up(&nodep->lock);
    if (destroy) {
        free(nodep->bp);
        free(nodep);
    }
}
 
fs_node_t *fat_create_node(dev_handle_t dev_handle, int flags)
{
    fat_idx_t *idxp;
    fat_node_t *nodep;
    fat_bs_t *bs;
    fat_cluster_t mcl, lcl;
    uint16_t bps;
    int rc;
 
    bs = block_bb_get(dev_handle);
    bps = uint16_t_le2host(bs->bps);
    if (flags & L_DIRECTORY) {
        /* allocate a cluster */
        rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);
        if (rc != EOK)
            return NULL;
    }
 
    nodep = fat_node_get_new();
    if (!nodep) {
        fat_free_clusters(bs, dev_handle, mcl);
        return NULL;
    }
    idxp = fat_idx_get_new(dev_handle);
    if (!idxp) {
        fat_free_clusters(bs, dev_handle, mcl);
        fat_node_put(FS_NODE(nodep));
        return NULL;
    }
    /* idxp->lock held */
    if (flags & L_DIRECTORY) {
        int i;
        block_t *b;
 
        /*
         * Populate the new cluster with unused dentries.
         */
        for (i = 0; i < bs->spc; i++) {
            b = _fat_block_get(bs, dev_handle, mcl, i,
                BLOCK_FLAGS_NOREAD);
            /* mark all dentries as never-used */
            memset(b->data, 0, bps);
            b->dirty = false;
            block_put(b);
        }
        nodep->type = FAT_DIRECTORY;
        nodep->firstc = mcl;
        nodep->size = bps * bs->spc;
    } else {
        nodep->type = FAT_FILE;
        nodep->firstc = FAT_CLST_RES0;
        nodep->size = 0;
    }
    nodep->lnkcnt = 0;  /* not linked anywhere */
    nodep->refcnt = 1;
    nodep->dirty = true;
 
    nodep->idx = idxp;
    idxp->nodep = nodep;
 
    futex_up(&idxp->lock);
    return FS_NODE(nodep);
}
 
int fat_destroy_node(fs_node_t *fn)
{
    fat_node_t *nodep = FAT_NODE(fn);
    fat_bs_t *bs;
 
    /*
     * The node is not reachable from the file system. This means that the
     * link count should be zero and that the index structure cannot be
     * found in the position hash. Obviously, we don't need to lock the node
     * nor its index structure.
     */
    assert(nodep->lnkcnt == 0);
 
    /*
     * The node may not have any children.
     */
    assert(fat_has_children(fn) == false);
 
    bs = block_bb_get(nodep->idx->dev_handle);
    if (nodep->firstc != FAT_CLST_RES0) {
        assert(nodep->size);
        /* Free all clusters allocated to the node. */
        fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
    }
 
    fat_idx_destroy(nodep->idx);
    free(nodep->bp);
    free(nodep);
    return EOK;
}
 
int fat_link(fs_node_t *pfn, fs_node_t *cfn, const char *name)
{
    fat_node_t *parentp = FAT_NODE(pfn);
    fat_node_t *childp = FAT_NODE(cfn);
    fat_dentry_t *d;
    fat_bs_t *bs;
    block_t *b;
    int i, j;
    uint16_t bps;
    unsigned dps;
    unsigned blocks;
    fat_cluster_t mcl, lcl;
    int rc;
 
    futex_down(&childp->lock);
    if (childp->lnkcnt == 1) {
        /*
         * On FAT, we don't support multiple hard links.
         */
        futex_up(&childp->lock);
        return EMLINK;
    }
    assert(childp->lnkcnt == 0);
    futex_up(&childp->lock);
 
    if (!fat_dentry_name_verify(name)) {
        /*
         * Attempt to create unsupported name.
         */
        return ENOTSUP;
    }
 
    /*
     * Get us an unused parent node's dentry or grow the parent and allocate
     * a new one.
     */
   
    futex_down(&parentp->idx->lock);
    bs = block_bb_get(parentp->idx->dev_handle);
    bps = uint16_t_le2host(bs->bps);
    dps = bps / sizeof(fat_dentry_t);
 
    blocks = parentp->size / bps;
 
    for (i = 0; i < blocks; i++) {
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
        for (j = 0; j < dps; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
            case FAT_DENTRY_VALID:
                /* skipping used and meta entries */
                continue;
            case FAT_DENTRY_FREE:
            case FAT_DENTRY_LAST:
                /* found an empty slot */
                goto hit;
            }
        }
        block_put(b);
    }
    j = 0;
   
    /*
     * We need to grow the parent in order to create a new unused dentry.
     */
    if (parentp->idx->pfc == FAT_CLST_ROOT) {
        /* Can't grow the root directory. */
        futex_up(&parentp->idx->lock);
        return ENOSPC;
    }
    rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);
    if (rc != EOK) {
        futex_up(&parentp->idx->lock);
        return rc;
    }
    fat_append_clusters(bs, parentp, mcl);
    b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);
    d = (fat_dentry_t *)b->data;
    /*
     * Clear all dentries in the block except for the first one (the first
     * dentry will be cleared in the next step).
     */
    memset(d + 1, 0, bps - sizeof(fat_dentry_t));
 
hit:
    /*
     * At this point we only establish the link between the parent and the
     * child.  The dentry, except of the name and the extension, will remain
     * uninitialized until the corresponding node is synced. Thus the valid
     * dentry data is kept in the child node structure.
     */
    memset(d, 0, sizeof(fat_dentry_t));
    fat_dentry_name_set(d, name);
    b->dirty = true;        /* need to sync block */
    block_put(b);
    futex_up(&parentp->idx->lock);
 
    futex_down(&childp->idx->lock);
   
    /*
     * If possible, create the Sub-directory Identifier Entry and the
     * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
     * are not mandatory according to Standard ECMA-107 and HelenOS VFS does
     * not use them anyway, so this is rather a sign of our good will.
     */
    b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE);
    d = (fat_dentry_t *)b->data;
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
        str_cmp(d->name, FAT_NAME_DOT) == 0) {
        memset(d, 0, sizeof(fat_dentry_t));
        str_cpy(d->name, 8, FAT_NAME_DOT);
        str_cpy(d->ext, 3, FAT_EXT_PAD);
        d->attr = FAT_ATTR_SUBDIR;
        d->firstc = host2uint16_t_le(childp->firstc);
        /* TODO: initialize also the date/time members. */
    }
    d++;
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
        str_cmp(d->name, FAT_NAME_DOT_DOT) == 0) {
        memset(d, 0, sizeof(fat_dentry_t));
        str_cpy(d->name, 8, FAT_NAME_DOT_DOT);
        str_cpy(d->ext, 3, FAT_EXT_PAD);
        d->attr = FAT_ATTR_SUBDIR;
        d->firstc = (parentp->firstc == FAT_CLST_ROOT) ?
            host2uint16_t_le(FAT_CLST_RES0) :
            host2uint16_t_le(parentp->firstc);
        /* TODO: initialize also the date/time members. */
    }
    b->dirty = true;        /* need to sync block */
    block_put(b);
 
    childp->idx->pfc = parentp->firstc;
    childp->idx->pdi = i * dps + j;
    futex_up(&childp->idx->lock);
 
    futex_down(&childp->lock);
    childp->lnkcnt = 1;
    childp->dirty = true;       /* need to sync node */
    futex_up(&childp->lock);
 
    /*
     * Hash in the index structure into the position hash.
     */
    fat_idx_hashin(childp->idx);
 
    return EOK;
}
 
int fat_unlink(fs_node_t *pfn, fs_node_t *cfn)
{
    fat_node_t *parentp = FAT_NODE(pfn);
    fat_node_t *childp = FAT_NODE(cfn);
    fat_bs_t *bs;
    fat_dentry_t *d;
    uint16_t bps;
    block_t *b;
 
    if (!parentp)
        return EBUSY;
 
    futex_down(&parentp->lock);
    futex_down(&childp->lock);
    assert(childp->lnkcnt == 1);
    futex_down(&childp->idx->lock);
    bs = block_bb_get(childp->idx->dev_handle);
    bps = uint16_t_le2host(bs->bps);
 
    b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc,
        (childp->idx->pdi * sizeof(fat_dentry_t)) / bps,
        BLOCK_FLAGS_NONE);
    d = (fat_dentry_t *)b->data +
        (childp->idx->pdi % (bps / sizeof(fat_dentry_t)));
    /* mark the dentry as not-currently-used */
    d->name[0] = FAT_DENTRY_ERASED;
    b->dirty = true;        /* need to sync block */
    block_put(b);
 
    /* remove the index structure from the position hash */
    fat_idx_hashout(childp->idx);
    /* clear position information */
    childp->idx->pfc = FAT_CLST_RES0;
    childp->idx->pdi = 0;
    futex_up(&childp->idx->lock);
    childp->lnkcnt = 0;
    childp->dirty = true;
    futex_up(&childp->lock);
    futex_up(&parentp->lock);
 
    return EOK;
}
 
fs_node_t *fat_match(fs_node_t *pfn, const char *component)
{
    fat_bs_t *bs;
    fat_node_t *parentp = FAT_NODE(pfn);
    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);
    bs = block_bb_get(parentp->idx->dev_handle);
    bps = uint16_t_le2host(bs->bps);
    dps = bps / sizeof(fat_dentry_t);
    blocks = parentp->size / bps;
    for (i = 0; i < blocks; i++) {
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
        for (j = 0; j < dps; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
            case FAT_DENTRY_FREE:
                continue;
            case FAT_DENTRY_LAST:
                block_put(b);
                futex_up(&parentp->idx->lock);
                return NULL;
            default:
            case FAT_DENTRY_VALID:
                fat_dentry_name_get(d, name);
                break;
            }
            if (fat_dentry_namecmp(name, component) == 0) {
                /* hit */
                fat_node_t *nodep;
                /*
                 * 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;
                }
                nodep = fat_node_get_core(idx);
                futex_up(&idx->lock);
                block_put(b);
                return FS_NODE(nodep);
            }
        }
        block_put(b);
    }
 
    futex_up(&parentp->idx->lock);
    return NULL;
}
 
fs_index_t fat_index_get(fs_node_t *fn)
{
    return FAT_NODE(fn)->idx->index;
}
 
size_t fat_size_get(fs_node_t *fn)
{
    return FAT_NODE(fn)->size;
}
 
unsigned fat_lnkcnt_get(fs_node_t *fn)
{
    return FAT_NODE(fn)->lnkcnt;
}
 
bool fat_has_children(fs_node_t *fn)
{
    fat_bs_t *bs;
    fat_node_t *nodep = FAT_NODE(fn);
    unsigned bps;
    unsigned dps;
    unsigned blocks;
    block_t *b;
    unsigned i, j;
 
    if (nodep->type != FAT_DIRECTORY)
        return false;
   
    futex_down(&nodep->idx->lock);
    bs = block_bb_get(nodep->idx->dev_handle);
    bps = uint16_t_le2host(bs->bps);
    dps = bps / sizeof(fat_dentry_t);
 
    blocks = nodep->size / bps;
 
    for (i = 0; i < blocks; i++) {
        fat_dentry_t *d;
   
        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
        for (j = 0; j < dps; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
            case FAT_DENTRY_FREE:
                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;
}
 
fs_node_t *fat_root_get(dev_handle_t dev_handle)
{
    return fat_node_get(dev_handle, 0);
}
 
char fat_plb_get_char(unsigned pos)
{
    return fat_reg.plb_ro[pos % PLB_SIZE];
}
 
bool fat_is_directory(fs_node_t *fn)
{
    return FAT_NODE(fn)->type == FAT_DIRECTORY;
}
 
bool fat_is_file(fs_node_t *fn)
{
    return FAT_NODE(fn)->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_node,
    .destroy = fat_destroy_node,
    .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
};
 
/*
 * VFS operations.
 */
 
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
    fat_bs_t *bs;
    uint16_t bps;
    uint16_t rde;
    int rc;
 
    /* accept the mount options */
    ipc_callid_t callid;
    size_t size;
    if (!ipc_data_write_receive(&callid, &size)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
    char *opts = malloc(size + 1);
    if (!opts) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);
    if (retval != EOK) {
        ipc_answer_0(rid, retval);
        free(opts);
        return;
    }
    opts[size] = '\0';
 
    /* initialize libblock */
    rc = block_init(dev_handle, BS_SIZE);
    if (rc != EOK) {
        ipc_answer_0(rid, rc);
        return;
    }
 
    /* prepare the boot block */
    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
    if (rc != EOK) {
        block_fini(dev_handle);
        ipc_answer_0(rid, rc);
        return;
    }
 
    /* get the buffer with the boot sector */
    bs = block_bb_get(dev_handle);
   
    /* Read the number of root directory entries. */
    bps = uint16_t_le2host(bs->bps);
    rde = uint16_t_le2host(bs->root_ent_max);
 
    if (bps != BS_SIZE) {
        block_fini(dev_handle);
        ipc_answer_0(rid, ENOTSUP);
        return;
    }
 
    /* Initialize the block cache */
    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
    if (rc != EOK) {
        block_fini(dev_handle);
        ipc_answer_0(rid, rc);
        return;
    }
 
    rc = fat_idx_init_by_dev_handle(dev_handle);
    if (rc != EOK) {
        block_fini(dev_handle);
        ipc_answer_0(rid, rc);
        return;
    }
 
    /* Initialize the root node. */
    fs_node_t *rfn = (fs_node_t *)malloc(sizeof(fs_node_t));
    if (!rfn) {
        block_fini(dev_handle);
        fat_idx_fini_by_dev_handle(dev_handle);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
    if (!rootp) {
        free(rfn);
        block_fini(dev_handle);
        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(rfn);
        free(rootp);
        block_fini(dev_handle);
        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->lnkcnt = 0;  /* FS root is not linked */
    rootp->size = rde * sizeof(fat_dentry_t);
    rootp->idx = ridxp;
    ridxp->nodep = rootp;
    rootp->bp = rfn;
    rfn->data = rootp;
   
    futex_up(&ridxp->lock);
 
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
}
 
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);
}
 
void fat_read(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
    off_t pos = (off_t)IPC_GET_ARG3(*request);
    fs_node_t *fn = fat_node_get(dev_handle, index);
    fat_node_t *nodep;
    fat_bs_t *bs;
    uint16_t bps;
    size_t bytes;
    block_t *b;
 
    if (!fn) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
    nodep = FAT_NODE(fn);
 
    ipc_callid_t callid;
    size_t len;
    if (!ipc_data_read_receive(&callid, &len)) {
        fat_node_put(fn);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    bs = block_bb_get(dev_handle);
    bps = uint16_t_le2host(bs->bps);
 
    if (nodep->type == FAT_FILE) {
        /*
         * Our strategy for regular file reads is to read one block at
         * most and make use of the possibility to return less data than
         * requested. This keeps the code very simple.
         */
        if (pos >= nodep->size) {
            /* reading beyond the EOF */
            bytes = 0;
            (void) ipc_data_read_finalize(callid, NULL, 0);
        } else {
            bytes = min(len, bps - pos % bps);
            bytes = min(bytes, nodep->size - pos);
            b = fat_block_get(bs, nodep, pos / bps,
                BLOCK_FLAGS_NONE);
            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
                bytes);
            block_put(b);
        }
    } else {
        unsigned bnum;
        off_t spos = pos;
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
        fat_dentry_t *d;
 
        assert(nodep->type == FAT_DIRECTORY);
        assert(nodep->size % bps == 0);
        assert(bps % sizeof(fat_dentry_t) == 0);
 
        /*
         * Our strategy for readdir() is to use the position pointer as
         * an index into the array of all dentries. On entry, it points
         * to the first unread dentry. If we skip any dentries, we bump
         * the position pointer accordingly.
         */
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
        while (bnum < nodep->size / bps) {
            off_t o;
 
            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
            for (o = pos % (bps / sizeof(fat_dentry_t));
                o < bps / sizeof(fat_dentry_t);
                o++, pos++) {
                d = ((fat_dentry_t *)b->data) + o;
                switch (fat_classify_dentry(d)) {
                case FAT_DENTRY_SKIP:
                case FAT_DENTRY_FREE:
                    continue;
                case FAT_DENTRY_LAST:
                    block_put(b);
                    goto miss;
                default:
                case FAT_DENTRY_VALID:
                    fat_dentry_name_get(d, name);
                    block_put(b);
                    goto hit;
                }
            }
            block_put(b);
            bnum++;
        }
miss:
        fat_node_put(fn);
        ipc_answer_0(callid, ENOENT);
        ipc_answer_1(rid, ENOENT, 0);
        return;
hit:
        (void) ipc_data_read_finalize(callid, name, str_size(name) + 1);
        bytes = (pos - spos) + 1;
    }
 
    fat_node_put(fn);
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
}
 
void fat_write(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
    off_t pos = (off_t)IPC_GET_ARG3(*request);
    fs_node_t *fn = fat_node_get(dev_handle, index);
    fat_node_t *nodep;
    fat_bs_t *bs;
    size_t bytes;
    block_t *b;
    uint16_t bps;
    unsigned spc;
    unsigned bpc;       /* bytes per cluster */
    off_t boundary;
    int flags = BLOCK_FLAGS_NONE;
   
    if (!fn) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
    nodep = FAT_NODE(fn);
   
    ipc_callid_t callid;
    size_t len;
    if (!ipc_data_write_receive(&callid, &len)) {
        fat_node_put(fn);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    bs = block_bb_get(dev_handle);
    bps = uint16_t_le2host(bs->bps);
    spc = bs->spc;
    bpc = bps * spc;
 
    /*
     * In all scenarios, we will attempt to write out only one block worth
     * of data at maximum. There might be some more efficient approaches,
     * but this one greatly simplifies fat_write(). Note that we can afford
     * to do this because the client must be ready to handle the return
     * value signalizing a smaller number of bytes written.
     */
    bytes = min(len, bps - pos % bps);
    if (bytes == bps)
        flags |= BLOCK_FLAGS_NOREAD;
   
    boundary = ROUND_UP(nodep->size, bpc);
    if (pos < boundary) {
        /*
         * This is the easier case - we are either overwriting already
         * existing contents or writing behind the EOF, but still within
         * the limits of the last cluster. The node size may grow to the
         * next block size boundary.
         */
        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
        b = fat_block_get(bs, nodep, pos / bps, flags);
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
            bytes);
        b->dirty = true;        /* need to sync block */
        block_put(b);
        if (pos + bytes > nodep->size) {
            nodep->size = pos + bytes;
            nodep->dirty = true;    /* need to sync node */
        }
        ipc_answer_2(rid, EOK, bytes, nodep->size);
        fat_node_put(fn);
        return;
    } else {
        /*
         * This is the more difficult case. We must allocate new
         * clusters for the node and zero them out.
         */
        int status;
        unsigned nclsts;
        fat_cluster_t mcl, lcl;
 
        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
        /* create an independent chain of nclsts clusters in all FATs */
        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
        if (status != EOK) {
            /* could not allocate a chain of nclsts clusters */
            fat_node_put(fn);
            ipc_answer_0(callid, status);
            ipc_answer_0(rid, status);
            return;
        }
        /* zero fill any gaps */
        fat_fill_gap(bs, nodep, mcl, pos);
        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
            flags);
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
            bytes);
        b->dirty = true;        /* need to sync block */
        block_put(b);
        /*
         * Append the cluster chain starting in mcl to the end of the
         * node's cluster chain.
         */
        fat_append_clusters(bs, nodep, mcl);
        nodep->size = pos + bytes;
        nodep->dirty = true;        /* need to sync node */
        ipc_answer_2(rid, EOK, bytes, nodep->size);
        fat_node_put(fn);
        return;
    }
}
 
void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
    size_t size = (off_t)IPC_GET_ARG3(*request);
    fs_node_t *fn = fat_node_get(dev_handle, index);
    fat_node_t *nodep;
    fat_bs_t *bs;
    uint16_t bps;
    uint8_t spc;
    unsigned bpc;   /* bytes per cluster */
    int rc;
 
    if (!fn) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
    nodep = FAT_NODE(fn);
 
    bs = block_bb_get(dev_handle);
    bps = uint16_t_le2host(bs->bps);
    spc = bs->spc;
    bpc = bps * spc;
 
    if (nodep->size == size) {
        rc = EOK;
    } else if (nodep->size < size) {
        /*
         * The standard says we have the freedom to grow the node.
         * For now, we simply return an error.
         */
        rc = EINVAL;
    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
        /*
         * The node will be shrunk, but no clusters will be deallocated.
         */
        nodep->size = size;
        nodep->dirty = true;        /* need to sync node */
        rc = EOK;  
    } else {
        /*
         * The node will be shrunk, clusters will be deallocated.
         */
        if (size == 0) {
            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
        } else {
            fat_cluster_t lastc;
            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
                &lastc, (size - 1) / bpc);
            fat_chop_clusters(bs, nodep, lastc);
        }
        nodep->size = size;
        nodep->dirty = true;        /* need to sync node */
        rc = EOK;  
    }
    fat_node_put(fn);
    ipc_answer_0(rid, rc);
    return;
}
 
void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
    int rc;
 
    fs_node_t *fn = fat_node_get(dev_handle, index);
    if (!fn) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    rc = fat_destroy_node(fn);
    ipc_answer_0(rid, rc);
}
 
/**
 * @}
 */
 

Rev 4357	Rev 4358
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 "fat_dentry.h"	39	#include "fat_dentry.h"
40	#include "fat_fat.h"	40	#include "fat_fat.h"
41	#include "../../vfs/vfs.h"	41	#include "../../vfs/vfs.h"
42	#include <libfs.h>	42	#include <libfs.h>
43	#include <libblock.h>	43	#include <libblock.h>
44	#include <ipc/ipc.h>	44	#include <ipc/ipc.h>
45	#include <ipc/services.h>	45	#include <ipc/services.h>
46	#include <ipc/devmap.h>	46	#include <ipc/devmap.h>
47	#include <async.h>	47	#include <async.h>
48	#include <errno.h>	48	#include <errno.h>
49	#include <string.h>	49	#include <string.h>
50	#include <byteorder.h>	50	#include <byteorder.h>
51	#include <libadt/hash_table.h>	51	#include <libadt/hash_table.h>
52	#include <libadt/list.h>	52	#include <libadt/list.h>
53	#include <assert.h>	53	#include <assert.h>
54	#include <futex.h>	54	#include <futex.h>
55	#include <sys/mman.h>	55	#include <sys/mman.h>
56	#include <align.h>	56	#include <align.h>
57		57
58	#define FAT_NODE(node) ((node) ? (fat_node_t *) (node)->data : NULL)	58	#define FAT_NODE(node) ((node) ? (fat_node_t *) (node)->data : NULL)
59	#define FS_NODE(node) ((node) ? (node)->bp : NULL)	59	#define FS_NODE(node) ((node) ? (node)->bp : NULL)
60		60
61	/** Futex protecting the list of cached free FAT nodes. */	61	/** Futex protecting the list of cached free FAT nodes. */
62	static futex_t ffn_futex = FUTEX_INITIALIZER;	62	static futex_t ffn_futex = FUTEX_INITIALIZER;
63		63
64	/** List of cached free FAT nodes. */	64	/** List of cached free FAT nodes. */
65	static LIST_INITIALIZE(ffn_head);	65	static LIST_INITIALIZE(ffn_head);
66		66
67	static void fat_node_initialize(fat_node_t *node)	67	static void fat_node_initialize(fat_node_t *node)
68	{	68	{
69	futex_initialize(&node->lock, 1);	69	futex_initialize(&node->lock, 1);
70	node->bp = NULL;	70	node->bp = NULL;
71	node->idx = NULL;	71	node->idx = NULL;
72	node->type = 0;	72	node->type = 0;
73	link_initialize(&node->ffn_link);	73	link_initialize(&node->ffn_link);
74	node->size = 0;	74	node->size = 0;
75	node->lnkcnt = 0;	75	node->lnkcnt = 0;
76	node->refcnt = 0;	76	node->refcnt = 0;
77	node->dirty = false;	77	node->dirty = false;
78	}	78	}
79		79
80	static void fat_node_sync(fat_node_t *node)	80	static void fat_node_sync(fat_node_t *node)
81	{	81	{
82	block_t *b;	82	block_t *b;
83	fat_bs_t *bs;	83	fat_bs_t *bs;
84	fat_dentry_t *d;	84	fat_dentry_t *d;
85	uint16_t bps;	85	uint16_t bps;
86	unsigned dps;	86	unsigned dps;
87		87
88	assert(node->dirty);	88	assert(node->dirty);
89		89
90	bs = block_bb_get(node->idx->dev_handle);	90	bs = block_bb_get(node->idx->dev_handle);
91	bps = uint16_t_le2host(bs->bps);	91	bps = uint16_t_le2host(bs->bps);
92	dps = bps / sizeof(fat_dentry_t);	92	dps = bps / sizeof(fat_dentry_t);
93		93
94	/* Read the block that contains the dentry of interest. */	94	/* Read the block that contains the dentry of interest. */
95	b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,	95	b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
96	(node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);	96	(node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
97		97
98	d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);	98	d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
99		99
100	d->firstc = host2uint16_t_le(node->firstc);	100	d->firstc = host2uint16_t_le(node->firstc);
101	if (node->type == FAT_FILE) {	101	if (node->type == FAT_FILE) {
102	d->size = host2uint32_t_le(node->size);	102	d->size = host2uint32_t_le(node->size);
103	} else if (node->type == FAT_DIRECTORY) {	103	} else if (node->type == FAT_DIRECTORY) {
104	d->attr = FAT_ATTR_SUBDIR;	104	d->attr = FAT_ATTR_SUBDIR;
105	}	105	}
106		106
107	/* TODO: update other fields? (e.g time fields) */	107	/* TODO: update other fields? (e.g time fields) */
108		108
109	b->dirty = true; /* need to sync block */	109	b->dirty = true; /* need to sync block */
110	block_put(b);	110	block_put(b);
111	}	111	}
112		112
113	static fat_node_t *fat_node_get_new(void)	113	static fat_node_t *fat_node_get_new(void)
114	{	114	{
115	fs_node_t *fn;	115	fs_node_t *fn;
116	fat_node_t *nodep;	116	fat_node_t *nodep;
117		117
118	futex_down(&ffn_futex);	118	futex_down(&ffn_futex);
119	if (!list_empty(&ffn_head)) {	119	if (!list_empty(&ffn_head)) {
120	/* Try to use a cached free node structure. */	120	/* Try to use a cached free node structure. */
121	fat_idx_t *idxp_tmp;	121	fat_idx_t *idxp_tmp;
122	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);	122	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
123	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)	123	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
124	goto skip_cache;	124	goto skip_cache;
125	idxp_tmp = nodep->idx;	125	idxp_tmp = nodep->idx;
126	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {	126	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
127	futex_up(&nodep->lock);	127	futex_up(&nodep->lock);
128	goto skip_cache;	128	goto skip_cache;
129	}	129	}
130	list_remove(&nodep->ffn_link);	130	list_remove(&nodep->ffn_link);
131	futex_up(&ffn_futex);	131	futex_up(&ffn_futex);
132	if (nodep->dirty)	132	if (nodep->dirty)
133	fat_node_sync(nodep);	133	fat_node_sync(nodep);
134	idxp_tmp->nodep = NULL;	134	idxp_tmp->nodep = NULL;
135	futex_up(&nodep->lock);	135	futex_up(&nodep->lock);
136	futex_up(&idxp_tmp->lock);	136	futex_up(&idxp_tmp->lock);
137	fn = FS_NODE(nodep);	137	fn = FS_NODE(nodep);
138	} else {	138	} else {
139	skip_cache:	139	skip_cache:
140	/* Try to allocate a new node structure. */	140	/* Try to allocate a new node structure. */
141	futex_up(&ffn_futex);	141	futex_up(&ffn_futex);
142	fn = (fs_node_t *)malloc(sizeof(fs_node_t));	142	fn = (fs_node_t *)malloc(sizeof(fs_node_t));
143	if (!fn)	143	if (!fn)
144	return NULL;	144	return NULL;
145	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	145	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
146	if (!nodep) {	146	if (!nodep) {
147	free(fn);	147	free(fn);
148	return NULL;	148	return NULL;
149	}	149	}
150	}	150	}
151	fat_node_initialize(nodep);	151	fat_node_initialize(nodep);
152	fn->data = nodep;	152	fn->data = nodep;
153	nodep->bp = fn;	153	nodep->bp = fn;
154		154
155	return nodep;	155	return nodep;
156	}	156	}
157		157
158	/** Internal version of fat_node_get().	158	/** Internal version of fat_node_get().
159	*	159	*
160	* @param idxp Locked index structure.	160	* @param idxp Locked index structure.
161	*/	161	*/
162	static fat_node_t fat_node_get_core(fat_idx_t idxp)	162	static fat_node_t fat_node_get_core(fat_idx_t idxp)
163	{	163	{
164	block_t *b;	164	block_t *b;
165	fat_bs_t *bs;	165	fat_bs_t *bs;
166	fat_dentry_t *d;	166	fat_dentry_t *d;
167	fat_node_t *nodep = NULL;	167	fat_node_t *nodep = NULL;
168	unsigned bps;	168	unsigned bps;
169	unsigned spc;	169	unsigned spc;
170	unsigned dps;	170	unsigned dps;
171		171
172	if (idxp->nodep) {	172	if (idxp->nodep) {
173	/*	173	/*
174	* We are lucky.	174	* We are lucky.
175	* The node is already instantiated in memory.	175	* The node is already instantiated in memory.
176	*/	176	*/
177	futex_down(&idxp->nodep->lock);	177	futex_down(&idxp->nodep->lock);
178	if (!idxp->nodep->refcnt++)	178	if (!idxp->nodep->refcnt++)
179	list_remove(&idxp->nodep->ffn_link);	179	list_remove(&idxp->nodep->ffn_link);
180	futex_up(&idxp->nodep->lock);	180	futex_up(&idxp->nodep->lock);
181	return idxp->nodep;	181	return idxp->nodep;
182	}	182	}
183		183
184	/*	184	/*
185	* We must instantiate the node from the file system.	185	* We must instantiate the node from the file system.
186	*/	186	*/
187		187
188	assert(idxp->pfc);	188	assert(idxp->pfc);
189		189
190	nodep = fat_node_get_new();	190	nodep = fat_node_get_new();
191	if (!nodep)	191	if (!nodep)
192	return NULL;	192	return NULL;
193		193
194	bs = block_bb_get(idxp->dev_handle);	194	bs = block_bb_get(idxp->dev_handle);
195	bps = uint16_t_le2host(bs->bps);	195	bps = uint16_t_le2host(bs->bps);
196	spc = bs->spc;	196	spc = bs->spc;
197	dps = bps / sizeof(fat_dentry_t);	197	dps = bps / sizeof(fat_dentry_t);
198		198
199	/* Read the block that contains the dentry of interest. */	199	/* Read the block that contains the dentry of interest. */
200	b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,	200	b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
201	(idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);	201	(idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
202	assert(b);	202	assert(b);
203		203
204	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);	204	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
205	if (d->attr & FAT_ATTR_SUBDIR) {	205	if (d->attr & FAT_ATTR_SUBDIR) {
206	/*	206	/*
207	* The only directory which does not have this bit set is the	207	* The only directory which does not have this bit set is the
208	* root directory itself. The root directory node is handled	208	* root directory itself. The root directory node is handled
209	* and initialized elsewhere.	209	* and initialized elsewhere.
210	*/	210	*/
211	nodep->type = FAT_DIRECTORY;	211	nodep->type = FAT_DIRECTORY;
212	/*	212	/*
213	* Unfortunately, the 'size' field of the FAT dentry is not	213	* Unfortunately, the 'size' field of the FAT dentry is not
214	* defined for the directory entry type. We must determine the	214	* defined for the directory entry type. We must determine the
215	* size of the directory by walking the FAT.	215	* size of the directory by walking the FAT.
216	*/	216	*/
217	nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,	217	nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
218	uint16_t_le2host(d->firstc));	218	uint16_t_le2host(d->firstc));
219	} else {	219	} else {
220	nodep->type = FAT_FILE;	220	nodep->type = FAT_FILE;
221	nodep->size = uint32_t_le2host(d->size);	221	nodep->size = uint32_t_le2host(d->size);
222	}	222	}
223	nodep->firstc = uint16_t_le2host(d->firstc);	223	nodep->firstc = uint16_t_le2host(d->firstc);
224	nodep->lnkcnt = 1;	224	nodep->lnkcnt = 1;
225	nodep->refcnt = 1;	225	nodep->refcnt = 1;
226		226
227	block_put(b);	227	block_put(b);
228		228
229	/* Link the idx structure with the node structure. */	229	/* Link the idx structure with the node structure. */
230	nodep->idx = idxp;	230	nodep->idx = idxp;
231	idxp->nodep = nodep;	231	idxp->nodep = nodep;
232		232
233	return nodep;	233	return nodep;
234	}	234	}
235		235
236	/*	236	/*
237	* Forward declarations of FAT libfs operations.	237	* Forward declarations of FAT libfs operations.
238	*/	238	*/
239	static fs_node_t *fat_node_get(dev_handle_t, fs_index_t);	239	static fs_node_t *fat_node_get(dev_handle_t, fs_index_t);
240	static void fat_node_put(fs_node_t *);	240	static void fat_node_put(fs_node_t *);
241	static fs_node_t *fat_create_node(dev_handle_t, int);	241	static fs_node_t *fat_create_node(dev_handle_t, int);
242	static int fat_destroy_node(fs_node_t *);	242	static int fat_destroy_node(fs_node_t *);
243	static int fat_link(fs_node_t , fs_node_t , const char *);	243	static int fat_link(fs_node_t , fs_node_t , const char *);
244	static int fat_unlink(fs_node_t , fs_node_t );	244	static int fat_unlink(fs_node_t , fs_node_t );
245	static fs_node_t fat_match(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 *);	246	static fs_index_t fat_index_get(fs_node_t *);
247	static size_t fat_size_get(fs_node_t *);	247	static size_t fat_size_get(fs_node_t *);
248	static unsigned fat_lnkcnt_get(fs_node_t *);	248	static unsigned fat_lnkcnt_get(fs_node_t *);
249	static bool fat_has_children(fs_node_t *);	249	static bool fat_has_children(fs_node_t *);
250	static fs_node_t *fat_root_get(dev_handle_t);	250	static fs_node_t *fat_root_get(dev_handle_t);
251	static char fat_plb_get_char(unsigned);	251	static char fat_plb_get_char(unsigned);
252	static bool fat_is_directory(fs_node_t *);	252	static bool fat_is_directory(fs_node_t *);
253	static bool fat_is_file(fs_node_t *node);	253	static bool fat_is_file(fs_node_t *node);
254		254
255	/*	255	/*
256	* FAT libfs operations.	256	* FAT libfs operations.
257	*/	257	*/
258		258
259	/** Instantiate a FAT in-core node. */	259	/** Instantiate a FAT in-core node. */
260	fs_node_t *fat_node_get(dev_handle_t dev_handle, fs_index_t index)	260	fs_node_t *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
261	{	261	{
262	fat_node_t *nodep;	262	fat_node_t *nodep;
263	fat_idx_t *idxp;	263	fat_idx_t *idxp;
264		264
265	idxp = fat_idx_get_by_index(dev_handle, index);	265	idxp = fat_idx_get_by_index(dev_handle, index);
266	if (!idxp)	266	if (!idxp)
267	return NULL;	267	return NULL;
268	/* idxp->lock held */	268	/* idxp->lock held */
269	nodep = fat_node_get_core(idxp);	269	nodep = fat_node_get_core(idxp);
270	futex_up(&idxp->lock);	270	futex_up(&idxp->lock);
271	return FS_NODE(nodep);	271	return FS_NODE(nodep);
272	}	272	}
273		273
274	void fat_node_put(fs_node_t *fn)	274	void fat_node_put(fs_node_t *fn)
275	{	275	{
276	fat_node_t *nodep = FAT_NODE(fn);	276	fat_node_t *nodep = FAT_NODE(fn);
277	bool destroy = false;	277	bool destroy = false;
278		278
279	futex_down(&nodep->lock);	279	futex_down(&nodep->lock);
280	if (!--nodep->refcnt) {	280	if (!--nodep->refcnt) {
281	if (nodep->idx) {	281	if (nodep->idx) {
282	futex_down(&ffn_futex);	282	futex_down(&ffn_futex);
283	list_append(&nodep->ffn_link, &ffn_head);	283	list_append(&nodep->ffn_link, &ffn_head);
284	futex_up(&ffn_futex);	284	futex_up(&ffn_futex);
285	} else {	285	} else {
286	/*	286	/*
287	* The node does not have any index structure associated	287	* The node does not have any index structure associated
288	* with itself. This can only mean that we are releasing	288	* with itself. This can only mean that we are releasing
289	* the node after a failed attempt to allocate the index	289	* the node after a failed attempt to allocate the index
290	* structure for it.	290	* structure for it.
291	*/	291	*/
292	destroy = true;	292	destroy = true;
293	}	293	}
294	}	294	}
295	futex_up(&nodep->lock);	295	futex_up(&nodep->lock);
296	if (destroy) {	296	if (destroy) {
297	free(nodep->bp);	297	free(nodep->bp);
298	free(nodep);	298	free(nodep);
299	}	299	}
300	}	300	}
301		301
302	fs_node_t *fat_create_node(dev_handle_t dev_handle, int flags)	302	fs_node_t *fat_create_node(dev_handle_t dev_handle, int flags)
303	{	303	{
304	fat_idx_t *idxp;	304	fat_idx_t *idxp;
305	fat_node_t *nodep;	305	fat_node_t *nodep;
306	fat_bs_t *bs;	306	fat_bs_t *bs;
307	fat_cluster_t mcl, lcl;	307	fat_cluster_t mcl, lcl;
308	uint16_t bps;	308	uint16_t bps;
309	int rc;	309	int rc;
310		310
311	bs = block_bb_get(dev_handle);	311	bs = block_bb_get(dev_handle);
312	bps = uint16_t_le2host(bs->bps);	312	bps = uint16_t_le2host(bs->bps);
313	if (flags & L_DIRECTORY) {	313	if (flags & L_DIRECTORY) {
314	/* allocate a cluster */	314	/* allocate a cluster */
315	rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);	315	rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);
316	if (rc != EOK)	316	if (rc != EOK)
317	return NULL;	317	return NULL;
318	}	318	}
319		319
320	nodep = fat_node_get_new();	320	nodep = fat_node_get_new();
321	if (!nodep) {	321	if (!nodep) {
322	fat_free_clusters(bs, dev_handle, mcl);	322	fat_free_clusters(bs, dev_handle, mcl);
323	return NULL;	323	return NULL;
324	}	324	}
325	idxp = fat_idx_get_new(dev_handle);	325	idxp = fat_idx_get_new(dev_handle);
326	if (!idxp) {	326	if (!idxp) {
327	fat_free_clusters(bs, dev_handle, mcl);	327	fat_free_clusters(bs, dev_handle, mcl);
328	fat_node_put(FS_NODE(nodep));	328	fat_node_put(FS_NODE(nodep));
329	return NULL;	329	return NULL;
330	}	330	}
331	/* idxp->lock held */	331	/* idxp->lock held */
332	if (flags & L_DIRECTORY) {	332	if (flags & L_DIRECTORY) {
333	int i;	333	int i;
334	block_t *b;	334	block_t *b;
335		335
336	/*	336	/*
337	* Populate the new cluster with unused dentries.	337	* Populate the new cluster with unused dentries.
338	*/	338	*/
339	for (i = 0; i < bs->spc; i++) {	339	for (i = 0; i < bs->spc; i++) {
340	b = _fat_block_get(bs, dev_handle, mcl, i,	340	b = _fat_block_get(bs, dev_handle, mcl, i,
341	BLOCK_FLAGS_NOREAD);	341	BLOCK_FLAGS_NOREAD);
342	/* mark all dentries as never-used */	342	/* mark all dentries as never-used */
343	memset(b->data, 0, bps);	343	memset(b->data, 0, bps);
344	b->dirty = false;	344	b->dirty = false;
345	block_put(b);	345	block_put(b);
346	}	346	}
347	nodep->type = FAT_DIRECTORY;	347	nodep->type = FAT_DIRECTORY;
348	nodep->firstc = mcl;	348	nodep->firstc = mcl;
349	nodep->size = bps * bs->spc;	349	nodep->size = bps * bs->spc;
350	} else {	350	} else {
351	nodep->type = FAT_FILE;	351	nodep->type = FAT_FILE;
352	nodep->firstc = FAT_CLST_RES0;	352	nodep->firstc = FAT_CLST_RES0;
353	nodep->size = 0;	353	nodep->size = 0;
354	}	354	}
355	nodep->lnkcnt = 0; /* not linked anywhere */	355	nodep->lnkcnt = 0; /* not linked anywhere */
356	nodep->refcnt = 1;	356	nodep->refcnt = 1;
357	nodep->dirty = true;	357	nodep->dirty = true;
358		358
359	nodep->idx = idxp;	359	nodep->idx = idxp;
360	idxp->nodep = nodep;	360	idxp->nodep = nodep;
361		361
362	futex_up(&idxp->lock);	362	futex_up(&idxp->lock);
363	return FS_NODE(nodep);	363	return FS_NODE(nodep);
364	}	364	}
365		365
366	int fat_destroy_node(fs_node_t *fn)	366	int fat_destroy_node(fs_node_t *fn)
367	{	367	{
368	fat_node_t *nodep = FAT_NODE(fn);	368	fat_node_t *nodep = FAT_NODE(fn);
369	fat_bs_t *bs;	369	fat_bs_t *bs;
370		370
371	/*	371	/*
372	* The node is not reachable from the file system. This means that the	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	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	374	* found in the position hash. Obviously, we don't need to lock the node
375	* nor its index structure.	375	* nor its index structure.
376	*/	376	*/
377	assert(nodep->lnkcnt == 0);	377	assert(nodep->lnkcnt == 0);
378		378
379	/*	379	/*
380	* The node may not have any children.	380	* The node may not have any children.
381	*/	381	*/
382	assert(fat_has_children(fn) == false);	382	assert(fat_has_children(fn) == false);
383		383
384	bs = block_bb_get(nodep->idx->dev_handle);	384	bs = block_bb_get(nodep->idx->dev_handle);
385	if (nodep->firstc != FAT_CLST_RES0) {	385	if (nodep->firstc != FAT_CLST_RES0) {
386	assert(nodep->size);	386	assert(nodep->size);
387	/* Free all clusters allocated to the node. */	387	/* Free all clusters allocated to the node. */
388	fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);	388	fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
389	}	389	}
390		390
391	fat_idx_destroy(nodep->idx);	391	fat_idx_destroy(nodep->idx);
392	free(nodep->bp);	392	free(nodep->bp);
393	free(nodep);	393	free(nodep);
394	return EOK;	394	return EOK;
395	}	395	}
396		396
397	int fat_link(fs_node_t pfn, fs_node_t cfn, const char *name)	397	int fat_link(fs_node_t pfn, fs_node_t cfn, const char *name)
398	{	398	{
399	fat_node_t *parentp = FAT_NODE(pfn);	399	fat_node_t *parentp = FAT_NODE(pfn);
400	fat_node_t *childp = FAT_NODE(cfn);	400	fat_node_t *childp = FAT_NODE(cfn);
401	fat_dentry_t *d;	401	fat_dentry_t *d;
402	fat_bs_t *bs;	402	fat_bs_t *bs;
403	block_t *b;	403	block_t *b;
404	int i, j;	404	int i, j;
405	uint16_t bps;	405	uint16_t bps;
406	unsigned dps;	406	unsigned dps;
407	unsigned blocks;	407	unsigned blocks;
408	fat_cluster_t mcl, lcl;	408	fat_cluster_t mcl, lcl;
409	int rc;	409	int rc;
410		410
411	futex_down(&childp->lock);	411	futex_down(&childp->lock);
412	if (childp->lnkcnt == 1) {	412	if (childp->lnkcnt == 1) {
413	/*	413	/*
414	* On FAT, we don't support multiple hard links.	414	* On FAT, we don't support multiple hard links.
415	*/	415	*/
416	futex_up(&childp->lock);	416	futex_up(&childp->lock);
417	return EMLINK;	417	return EMLINK;
418	}	418	}
419	assert(childp->lnkcnt == 0);	419	assert(childp->lnkcnt == 0);
420	futex_up(&childp->lock);	420	futex_up(&childp->lock);
421		421
422	if (!fat_dentry_name_verify(name)) {	422	if (!fat_dentry_name_verify(name)) {
423	/*	423	/*
424	* Attempt to create unsupported name.	424	* Attempt to create unsupported name.
425	*/	425	*/
426	return ENOTSUP;	426	return ENOTSUP;
427	}	427	}
428		428
429	/*	429	/*
430	* Get us an unused parent node's dentry or grow the parent and allocate	430	* Get us an unused parent node's dentry or grow the parent and allocate
431	* a new one.	431	* a new one.
432	*/	432	*/
433		433
434	futex_down(&parentp->idx->lock);	434	futex_down(&parentp->idx->lock);
435	bs = block_bb_get(parentp->idx->dev_handle);	435	bs = block_bb_get(parentp->idx->dev_handle);
436	bps = uint16_t_le2host(bs->bps);	436	bps = uint16_t_le2host(bs->bps);
437	dps = bps / sizeof(fat_dentry_t);	437	dps = bps / sizeof(fat_dentry_t);
438		438
439	blocks = parentp->size / bps;	439	blocks = parentp->size / bps;
440		440
441	for (i = 0; i < blocks; i++) {	441	for (i = 0; i < blocks; i++) {
442	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);	442	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
443	for (j = 0; j < dps; j++) {	443	for (j = 0; j < dps; j++) {
444	d = ((fat_dentry_t *)b->data) + j;	444	d = ((fat_dentry_t *)b->data) + j;
445	switch (fat_classify_dentry(d)) {	445	switch (fat_classify_dentry(d)) {
446	case FAT_DENTRY_SKIP:	446	case FAT_DENTRY_SKIP:
447	case FAT_DENTRY_VALID:	447	case FAT_DENTRY_VALID:
448	/* skipping used and meta entries */	448	/* skipping used and meta entries */
449	continue;	449	continue;
450	case FAT_DENTRY_FREE:	450	case FAT_DENTRY_FREE:
451	case FAT_DENTRY_LAST:	451	case FAT_DENTRY_LAST:
452	/* found an empty slot */	452	/* found an empty slot */
453	goto hit;	453	goto hit;
454	}	454	}
455	}	455	}
456	block_put(b);	456	block_put(b);
457	}	457	}
458	j = 0;	458	j = 0;
459		459
460	/*	460	/*
461	* We need to grow the parent in order to create a new unused dentry.	461	* We need to grow the parent in order to create a new unused dentry.
462	*/	462	*/
463	if (parentp->idx->pfc == FAT_CLST_ROOT) {	463	if (parentp->idx->pfc == FAT_CLST_ROOT) {
464	/* Can't grow the root directory. */	464	/* Can't grow the root directory. */
465	futex_up(&parentp->idx->lock);	465	futex_up(&parentp->idx->lock);
466	return ENOSPC;	466	return ENOSPC;
467	}	467	}
468	rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);	468	rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);
469	if (rc != EOK) {	469	if (rc != EOK) {
470	futex_up(&parentp->idx->lock);	470	futex_up(&parentp->idx->lock);
471	return rc;	471	return rc;
472	}	472	}
473	fat_append_clusters(bs, parentp, mcl);	473	fat_append_clusters(bs, parentp, mcl);
474	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);	474	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);
475	d = (fat_dentry_t *)b->data;	475	d = (fat_dentry_t *)b->data;
476	/*	476	/*
477	* Clear all dentries in the block except for the first one (the first	477	* Clear all dentries in the block except for the first one (the first
478	* dentry will be cleared in the next step).	478	* dentry will be cleared in the next step).
479	*/	479	*/
480	memset(d + 1, 0, bps - sizeof(fat_dentry_t));	480	memset(d + 1, 0, bps - sizeof(fat_dentry_t));
481		481
482	hit:	482	hit:
483	/*	483	/*
484	* At this point we only establish the link between the parent and the	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	485	* child. The dentry, except of the name and the extension, will remain
486	* uninitialized until the corresponding node is synced. Thus the valid	486	* uninitialized until the corresponding node is synced. Thus the valid
487	* dentry data is kept in the child node structure.	487	* dentry data is kept in the child node structure.
488	*/	488	*/
489	memset(d, 0, sizeof(fat_dentry_t));	489	memset(d, 0, sizeof(fat_dentry_t));
490	fat_dentry_name_set(d, name);	490	fat_dentry_name_set(d, name);
491	b->dirty = true; /* need to sync block */	491	b->dirty = true; /* need to sync block */
492	block_put(b);	492	block_put(b);
493	futex_up(&parentp->idx->lock);	493	futex_up(&parentp->idx->lock);
494		494
495	futex_down(&childp->idx->lock);	495	futex_down(&childp->idx->lock);
496		496
497	/*	497	/*
498	* If possible, create the Sub-directory Identifier Entry and the	498	* If possible, create the Sub-directory Identifier Entry and the
499	* Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries	499	* Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
500	* are not mandatory according to Standard ECMA-107 and HelenOS VFS does	500	* are not mandatory according to Standard ECMA-107 and HelenOS VFS does

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c – Rev 4357 → 4358