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>
 
/** 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->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);
    /* TODO: update other fields? (e.g time fields, attr field) */
   
    b->dirty = true;        /* need to sync block */
    block_put(b);
}
 
static fat_node_t *fat_node_get_new(void)
{
    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);
    } 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);
   
    return nodep;
}
 
/** 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_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 void *fat_node_get(dev_handle_t, fs_index_t);
static void fat_node_put(void *);
static void *fat_create_node(dev_handle_t, int);
static int fat_destroy_node(void *);
static int fat_link(void *, void *, const char *);
static int fat_unlink(void *, void *);
static void *fat_match(void *, const char *);
static fs_index_t fat_index_get(void *);
static size_t fat_size_get(void *);
static unsigned fat_lnkcnt_get(void *);
static bool fat_has_children(void *);
static void *fat_root_get(dev_handle_t);
static char fat_plb_get_char(unsigned);
static bool fat_is_directory(void *);
static bool fat_is_file(void *node);
 
/*
 * FAT libfs operations.
 */
 
/** Instantiate a FAT in-core node. */
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;
}
 
void fat_node_put(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
    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(node);
}
 
void *fat_create_node(dev_handle_t dev_handle, int flags)
{
    fat_idx_t *idxp;
    fat_node_t *nodep;
 
    nodep = fat_node_get_new();
    if (!nodep)
        return NULL;
    idxp = fat_idx_get_new(dev_handle);
    if (!idxp) {
        fat_node_put(nodep);
        return NULL;
    }
    /* idxp->lock held */
    if (flags & L_DIRECTORY) {
        nodep->type = FAT_DIRECTORY;
    } else {
        nodep->type = FAT_FILE;
    }
    nodep->size = 0;
    nodep->firstc = FAT_CLST_RES0;
    nodep->lnkcnt = 0;  /* not linked anywhere */
    nodep->refcnt = 1;
 
    nodep->idx = idxp;
    idxp->nodep = nodep;
 
    futex_up(&idxp->lock);
    return nodep;
}
 
int fat_destroy_node(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
    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(node) == 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);
    return EOK;
}
 
int fat_link(void *prnt, void *chld, const char *name)
{
    fat_node_t *parentp = (fat_node_t *)prnt;
    fat_node_t *childp = (fat_node_t *)chld;
    fat_dentry_t *d;
    fat_bs_t *bs;
    block_t *b;
    int i, j;
    uint16_t bps;
    unsigned dps;
    unsigned blocks;
 
    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);
    }
   
    /*
     * We need to grow the parent in order to create a new unused dentry.
     */
    futex_up(&parentp->idx->lock);
    return ENOTSUP; /* XXX */
 
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 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);
    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(void *prnt, void *chld)
{
    return ENOTSUP; /* not supported at the moment */
}
 
void *fat_match(void *prnt, const char *component)
{
    fat_bs_t *bs;
    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);
    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 (stricmp(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;
}
 
fs_index_t fat_index_get(void *node)
{
    fat_node_t *fnodep = (fat_node_t *)node;
    if (!fnodep)
        return 0;
    return fnodep->idx->index;
}
 
size_t fat_size_get(void *node)
{
    return ((fat_node_t *)node)->size;
}
 
unsigned fat_lnkcnt_get(void *node)
{
    return ((fat_node_t *)node)->lnkcnt;
}
 
bool fat_has_children(void *node)
{
    fat_bs_t *bs;
    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);
    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;
}
 
void *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(void *node)
{
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
}
 
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_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;
 
    /* 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. */
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
    if (!rootp) {
        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) {
        block_fini(dev_handle);
        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->lnkcnt = 0;  /* FS root is not linked */
    rootp->size = rde * sizeof(fat_dentry_t);
    rootp->idx = ridxp;
    ridxp->nodep = 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);
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
    fat_bs_t *bs;
    uint16_t bps;
    size_t bytes;
    block_t *b;
 
    if (!nodep) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    ipc_callid_t callid;
    size_t len;
    if (!ipc_data_read_receive(&callid, &len)) {
        fat_node_put(nodep);
        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(nodep);
        ipc_answer_0(callid, ENOENT);
        ipc_answer_1(rid, ENOENT, 0);
        return;
hit:
        (void) ipc_data_read_finalize(callid, name, strlen(name) + 1);
        bytes = (pos - spos) + 1;
    }
 
    fat_node_put(nodep);
    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);
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
    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 (!nodep) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
   
    ipc_callid_t callid;
    size_t len;
    if (!ipc_data_write_receive(&callid, &len)) {
        fat_node_put(nodep);
        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(nodep);
        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(nodep);
            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(nodep);
        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);
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
    fat_bs_t *bs;
    uint16_t bps;
    uint8_t spc;
    unsigned bpc;   /* bytes per cluster */
    int rc;
 
    if (!nodep) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    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(nodep);
    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;
 
    fat_node_t *nodep = fat_node_get(dev_handle, index);
    if (!nodep) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    rc = fat_destroy_node(nodep);
    ipc_answer_0(rid, rc);
}
 
/**
 * @}
 */
 

Rev 3625	Rev 3628
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	/** Futex protecting the list of cached free FAT nodes. */	58	/** Futex protecting the list of cached free FAT nodes. */
59	static futex_t ffn_futex = FUTEX_INITIALIZER;	59	static futex_t ffn_futex = FUTEX_INITIALIZER;
60		60
61	/** List of cached free FAT nodes. */	61	/** List of cached free FAT nodes. */
62	static LIST_INITIALIZE(ffn_head);	62	static LIST_INITIALIZE(ffn_head);
63		63
64	static void fat_node_initialize(fat_node_t *node)	64	static void fat_node_initialize(fat_node_t *node)
65	{	65	{
66	futex_initialize(&node->lock, 1);	66	futex_initialize(&node->lock, 1);
67	node->idx = NULL;	67	node->idx = NULL;
68	node->type = 0;	68	node->type = 0;
69	link_initialize(&node->ffn_link);	69	link_initialize(&node->ffn_link);
70	node->size = 0;	70	node->size = 0;
71	node->lnkcnt = 0;	71	node->lnkcnt = 0;
72	node->refcnt = 0;	72	node->refcnt = 0;
73	node->dirty = false;	73	node->dirty = false;
74	}	74	}
75		75
76	static void fat_node_sync(fat_node_t *node)	76	static void fat_node_sync(fat_node_t *node)
77	{	77	{
78	block_t *b;	78	block_t *b;
79	fat_bs_t *bs;	79	fat_bs_t *bs;
80	fat_dentry_t *d;	80	fat_dentry_t *d;
81	uint16_t bps;	81	uint16_t bps;
82	unsigned dps;	82	unsigned dps;
83		83
84	assert(node->dirty);	84	assert(node->dirty);
85		85
86	bs = block_bb_get(node->idx->dev_handle);	86	bs = block_bb_get(node->idx->dev_handle);
87	bps = uint16_t_le2host(bs->bps);	87	bps = uint16_t_le2host(bs->bps);
88	dps = bps / sizeof(fat_dentry_t);	88	dps = bps / sizeof(fat_dentry_t);
89		89
90	/* Read the block that contains the dentry of interest. */	90	/* Read the block that contains the dentry of interest. */
91	b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,	91	b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
92	(node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);	92	(node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
93		93
94	d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);	94	d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
95		95
96	d->firstc = host2uint16_t_le(node->firstc);	96	d->firstc = host2uint16_t_le(node->firstc);
97	if (node->type == FAT_FILE)	97	if (node->type == FAT_FILE)
98	d->size = host2uint32_t_le(node->size);	98	d->size = host2uint32_t_le(node->size);
99	/* TODO: update other fields? (e.g time fields, attr field) */	99	/* TODO: update other fields? (e.g time fields, attr field) */
100		100
101	b->dirty = true; /* need to sync block */	101	b->dirty = true; /* need to sync block */
102	block_put(b);	102	block_put(b);
103	}	103	}
104		104
105	static fat_node_t *fat_node_get_new(void)	105	static fat_node_t *fat_node_get_new(void)
106	{	106	{
107	fat_node_t *nodep;	107	fat_node_t *nodep;
108		108
109	futex_down(&ffn_futex);	109	futex_down(&ffn_futex);
110	if (!list_empty(&ffn_head)) {	110	if (!list_empty(&ffn_head)) {
111	/* Try to use a cached free node structure. */	111	/* Try to use a cached free node structure. */
112	fat_idx_t *idxp_tmp;	112	fat_idx_t *idxp_tmp;
113	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);	113	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
114	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)	114	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
115	goto skip_cache;	115	goto skip_cache;
116	idxp_tmp = nodep->idx;	116	idxp_tmp = nodep->idx;
117	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {	117	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
118	futex_up(&nodep->lock);	118	futex_up(&nodep->lock);
119	goto skip_cache;	119	goto skip_cache;
120	}	120	}
121	list_remove(&nodep->ffn_link);	121	list_remove(&nodep->ffn_link);
122	futex_up(&ffn_futex);	122	futex_up(&ffn_futex);
123	if (nodep->dirty)	123	if (nodep->dirty)
124	fat_node_sync(nodep);	124	fat_node_sync(nodep);
125	idxp_tmp->nodep = NULL;	125	idxp_tmp->nodep = NULL;
126	futex_up(&nodep->lock);	126	futex_up(&nodep->lock);
127	futex_up(&idxp_tmp->lock);	127	futex_up(&idxp_tmp->lock);
128	} else {	128	} else {
129	skip_cache:	129	skip_cache:
130	/* Try to allocate a new node structure. */	130	/* Try to allocate a new node structure. */
131	futex_up(&ffn_futex);	131	futex_up(&ffn_futex);
132	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	132	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
133	if (!nodep)	133	if (!nodep)
134	return NULL;	134	return NULL;
135	}	135	}
136	fat_node_initialize(nodep);	136	fat_node_initialize(nodep);
137		137
138	return nodep;	138	return nodep;
139	}	139	}
140		140
141	/** Internal version of fat_node_get().	141	/** Internal version of fat_node_get().
142	*	142	*
143	* @param idxp Locked index structure.	143	* @param idxp Locked index structure.
144	*/	144	*/
145	static void fat_node_get_core(fat_idx_t idxp)	145	static void fat_node_get_core(fat_idx_t idxp)
146	{	146	{
147	block_t *b;	147	block_t *b;
148	fat_bs_t *bs;	148	fat_bs_t *bs;
149	fat_dentry_t *d;	149	fat_dentry_t *d;
150	fat_node_t *nodep = NULL;	150	fat_node_t *nodep = NULL;
151	unsigned bps;	151	unsigned bps;
152	unsigned spc;	152	unsigned spc;
153	unsigned dps;	153	unsigned dps;
154		154
155	if (idxp->nodep) {	155	if (idxp->nodep) {
156	/*	156	/*
157	* We are lucky.	157	* We are lucky.
158	* The node is already instantiated in memory.	158	* The node is already instantiated in memory.
159	*/	159	*/
160	futex_down(&idxp->nodep->lock);	160	futex_down(&idxp->nodep->lock);
161	if (!idxp->nodep->refcnt++)	161	if (!idxp->nodep->refcnt++)
162	list_remove(&idxp->nodep->ffn_link);	162	list_remove(&idxp->nodep->ffn_link);
163	futex_up(&idxp->nodep->lock);	163	futex_up(&idxp->nodep->lock);
164	return idxp->nodep;	164	return idxp->nodep;
165	}	165	}
166		166
167	/*	167	/*
168	* We must instantiate the node from the file system.	168	* We must instantiate the node from the file system.
169	*/	169	*/
170		170
171	assert(idxp->pfc);	171	assert(idxp->pfc);
172		172
173	nodep = fat_node_get_new();	173	nodep = fat_node_get_new();
174	if (!nodep)	174	if (!nodep)
175	return NULL;	175	return NULL;
176		176
177	bs = block_bb_get(idxp->dev_handle);	177	bs = block_bb_get(idxp->dev_handle);
178	bps = uint16_t_le2host(bs->bps);	178	bps = uint16_t_le2host(bs->bps);
179	spc = bs->spc;	179	spc = bs->spc;
180	dps = bps / sizeof(fat_dentry_t);	180	dps = bps / sizeof(fat_dentry_t);
181		181
182	/* Read the block that contains the dentry of interest. */	182	/* Read the block that contains the dentry of interest. */
183	b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,	183	b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
184	(idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);	184	(idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
185	assert(b);	185	assert(b);
186		186
187	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);	187	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
188	if (d->attr & FAT_ATTR_SUBDIR) {	188	if (d->attr & FAT_ATTR_SUBDIR) {
189	/*	189	/*
190	* The only directory which does not have this bit set is the	190	* The only directory which does not have this bit set is the
191	* root directory itself. The root directory node is handled	191	* root directory itself. The root directory node is handled
192	* and initialized elsewhere.	192	* and initialized elsewhere.
193	*/	193	*/
194	nodep->type = FAT_DIRECTORY;	194	nodep->type = FAT_DIRECTORY;
195	/*	195	/*
196	* Unfortunately, the 'size' field of the FAT dentry is not	196	* Unfortunately, the 'size' field of the FAT dentry is not
197	* defined for the directory entry type. We must determine the	197	* defined for the directory entry type. We must determine the
198	* size of the directory by walking the FAT.	198	* size of the directory by walking the FAT.
199	*/	199	*/
200	nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,	200	nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
201	uint16_t_le2host(d->firstc));	201	uint16_t_le2host(d->firstc));
202	} else {	202	} else {
203	nodep->type = FAT_FILE;	203	nodep->type = FAT_FILE;
204	nodep->size = uint32_t_le2host(d->size);	204	nodep->size = uint32_t_le2host(d->size);
205	}	205	}
206	nodep->firstc = uint16_t_le2host(d->firstc);	206	nodep->firstc = uint16_t_le2host(d->firstc);
207	nodep->lnkcnt = 1;	207	nodep->lnkcnt = 1;
208	nodep->refcnt = 1;	208	nodep->refcnt = 1;
209		209
210	block_put(b);	210	block_put(b);
211		211
212	/* Link the idx structure with the node structure. */	212	/* Link the idx structure with the node structure. */
213	nodep->idx = idxp;	213	nodep->idx = idxp;
214	idxp->nodep = nodep;	214	idxp->nodep = nodep;
215		215
216	return nodep;	216	return nodep;
217	}	217	}
218		218
219	/*	219	/*
220	* Forward declarations of FAT libfs operations.	220	* Forward declarations of FAT libfs operations.
221	*/	221	*/
222	static void *fat_node_get(dev_handle_t, fs_index_t);	222	static void *fat_node_get(dev_handle_t, fs_index_t);
223	static void fat_node_put(void *);	223	static void fat_node_put(void *);
224	static void *fat_create_node(dev_handle_t, int);	224	static void *fat_create_node(dev_handle_t, int);
225	static int fat_destroy_node(void *);	225	static int fat_destroy_node(void *);
226	static int fat_link(void , void , const char *);	226	static int fat_link(void , void , const char *);
227	static int fat_unlink(void , void );	227	static int fat_unlink(void , void );
228	static void fat_match(void , const char *);	228	static void fat_match(void , const char *);
229	static fs_index_t fat_index_get(void *);	229	static fs_index_t fat_index_get(void *);
230	static size_t fat_size_get(void *);	230	static size_t fat_size_get(void *);
231	static unsigned fat_lnkcnt_get(void *);	231	static unsigned fat_lnkcnt_get(void *);
232	static bool fat_has_children(void *);	232	static bool fat_has_children(void *);
233	static void *fat_root_get(dev_handle_t);	233	static void *fat_root_get(dev_handle_t);
234	static char fat_plb_get_char(unsigned);	234	static char fat_plb_get_char(unsigned);
235	static bool fat_is_directory(void *);	235	static bool fat_is_directory(void *);
236	static bool fat_is_file(void *node);	236	static bool fat_is_file(void *node);
237		237
238	/*	238	/*
239	* FAT libfs operations.	239	* FAT libfs operations.
240	*/	240	*/
241		241
242	/** Instantiate a FAT in-core node. */	242	/** Instantiate a FAT in-core node. */
243	void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)	243	void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
244	{	244	{
245	void *node;	245	void *node;
246	fat_idx_t *idxp;	246	fat_idx_t *idxp;
247		247
248	idxp = fat_idx_get_by_index(dev_handle, index);	248	idxp = fat_idx_get_by_index(dev_handle, index);
249	if (!idxp)	249	if (!idxp)
250	return NULL;	250	return NULL;
251	/* idxp->lock held */	251	/* idxp->lock held */
252	node = fat_node_get_core(idxp);	252	node = fat_node_get_core(idxp);
253	futex_up(&idxp->lock);	253	futex_up(&idxp->lock);
254	return node;	254	return node;
255	}	255	}
256		256
257	void fat_node_put(void *node)	257	void fat_node_put(void *node)
258	{	258	{
259	fat_node_t nodep = (fat_node_t )node;	259	fat_node_t nodep = (fat_node_t )node;
260	bool destroy = false;	260	bool destroy = false;
261		261
262	futex_down(&nodep->lock);	262	futex_down(&nodep->lock);
263	if (!--nodep->refcnt) {	263	if (!--nodep->refcnt) {
264	if (nodep->idx) {	264	if (nodep->idx) {
265	futex_down(&ffn_futex);	265	futex_down(&ffn_futex);
266	list_append(&nodep->ffn_link, &ffn_head);	266	list_append(&nodep->ffn_link, &ffn_head);
267	futex_up(&ffn_futex);	267	futex_up(&ffn_futex);
268	} else {	268	} else {
269	/*	269	/*
270	* The node does not have any index structure associated	270	* The node does not have any index structure associated
271	* with itself. This can only mean that we are releasing	271	* with itself. This can only mean that we are releasing
272	* the node after a failed attempt to allocate the index	272	* the node after a failed attempt to allocate the index
273	* structure for it.	273	* structure for it.
274	*/	274	*/
275	destroy = true;	275	destroy = true;
276	}	276	}
277	}	277	}
278	futex_up(&nodep->lock);	278	futex_up(&nodep->lock);
279	if (destroy)	279	if (destroy)
280	free(node);	280	free(node);
281	}	281	}
282		282
283	void *fat_create_node(dev_handle_t dev_handle, int flags)	283	void *fat_create_node(dev_handle_t dev_handle, int flags)
284	{	284	{
285	fat_idx_t *idxp;	285	fat_idx_t *idxp;
286	fat_node_t *nodep;	286	fat_node_t *nodep;
287		287
288	nodep = fat_node_get_new();	288	nodep = fat_node_get_new();
289	if (!nodep)	289	if (!nodep)
290	return NULL;	290	return NULL;
291	idxp = fat_idx_get_new(dev_handle);	291	idxp = fat_idx_get_new(dev_handle);
292	if (!idxp) {	292	if (!idxp) {
293	fat_node_put(nodep);	293	fat_node_put(nodep);
294	return NULL;	294	return NULL;
295	}	295	}
296	/* idxp->lock held */	296	/* idxp->lock held */
297	if (flags & L_DIRECTORY) {	297	if (flags & L_DIRECTORY) {
298	nodep->type = FAT_DIRECTORY;	298	nodep->type = FAT_DIRECTORY;
299	} else {	299	} else {
300	nodep->type = FAT_FILE;	300	nodep->type = FAT_FILE;
301	}	301	}
302	nodep->size = 0;	302	nodep->size = 0;
303	nodep->firstc = FAT_CLST_RES0;	303	nodep->firstc = FAT_CLST_RES0;
304	nodep->lnkcnt = 0; /* not linked anywhere */	304	nodep->lnkcnt = 0; /* not linked anywhere */
305	nodep->refcnt = 1;	305	nodep->refcnt = 1;
306		306
307	nodep->idx = idxp;	307	nodep->idx = idxp;
308	idxp->nodep = nodep;	308	idxp->nodep = nodep;
309		309
310	futex_up(&idxp->lock);	310	futex_up(&idxp->lock);
311	return nodep;	311	return nodep;
312	}	312	}
313		313
314	int fat_destroy_node(void *node)	314	int fat_destroy_node(void *node)
315	{	315	{
316	fat_node_t nodep = (fat_node_t )node;	316	fat_node_t nodep = (fat_node_t )node;
317	fat_bs_t *bs;	317	fat_bs_t *bs;
318		318
319	/*	319	/*
320	* The node is not reachable from the file system. This means that the	320	* The node is not reachable from the file system. This means that the
321	* link count should be zero and that the index structure cannot be	321	* link count should be zero and that the index structure cannot be
322	* found in the position hash. Obviously, we don't need to lock the node	322	* found in the position hash. Obviously, we don't need to lock the node
323	* nor its index structure.	323	* nor its index structure.
324	*/	324	*/
325	assert(nodep->lnkcnt == 0);	325	assert(nodep->lnkcnt == 0);
326		326
327	/*	327	/*
328	* The node may not have any children.	328	* The node may not have any children.
329	*/	329	*/
330	assert(fat_has_children(node) == false);	330	assert(fat_has_children(node) == false);
331		331
332	bs = block_bb_get(nodep->idx->dev_handle);	332	bs = block_bb_get(nodep->idx->dev_handle);
333	if (nodep->firstc != FAT_CLST_RES0) {	333	if (nodep->firstc != FAT_CLST_RES0) {
334	assert(nodep->size);	334	assert(nodep->size);
335	/* Free all clusters allocated to the node. */	335	/* Free all clusters allocated to the node. */
336	fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);	336	fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
337	}	337	}
338		338
339	fat_idx_destroy(nodep->idx);	339	fat_idx_destroy(nodep->idx);
340	free(nodep);	340	free(nodep);
341	return EOK;	341	return EOK;
342	}	342	}
343		343
344	int fat_link(void prnt, void chld, const char *name)	344	int fat_link(void prnt, void chld, const char *name)
345	{	345	{
-		346	fat_node_t parentp = (fat_node_t )prnt;
-		347	fat_node_t childp = (fat_node_t )chld;
-		348	fat_dentry_t *d;
-		349	fat_bs_t *bs;
-		350	block_t *b;
-		351	int i, j;
-		352	uint16_t bps;
-		353	unsigned dps;
-		354	unsigned blocks;
-		355
-		356	futex_down(&childp->lock);
-		357	if (childp->lnkcnt == 1) {
-		358	/*
346	return ENOTSUP; /* not supported at the moment */	359	* On FAT, we don't support multiple hard links.
-		360	*/
-		361	futex_up(&childp->lock);
-		362	return EMLINK;
-		363	}
-		364	assert(childp->lnkcnt == 0);
-		365	futex_up(&childp->lock);
-		366
-		367	if (!fat_dentry_name_verify(name)) {
-		368	/*
-		369	* Attempt to create unsupported name.
-		370	*/
-		371	return ENOTSUP;
-		372	}
-		373
-		374	/*
-		375	* Get us an unused parent node's dentry or grow the parent and allocate
-		376	* a new one.
-		377	*/
-		378
-		379	futex_down(&parentp->idx->lock);
-		380	bs = block_bb_get(parentp->idx->dev_handle);
-		381	bps = uint16_t_le2host(bs->bps);
-		382	dps = bps / sizeof(fat_dentry_t);
-		383
-		384	blocks = parentp->size / bps;
-		385
-		386	for (i = 0; i < blocks; i++) {
-		387	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
-		388	for (j = 0; j < dps; j++) {
-		389	d = ((fat_dentry_t *)b->data) + j;
-		390	switch (fat_classify_dentry(d)) {
-		391	case FAT_DENTRY_SKIP:
-		392	case FAT_DENTRY_VALID:
-		393	/* skipping used and meta entries */
-		394	continue;
-		395	case FAT_DENTRY_FREE:
-		396	case FAT_DENTRY_LAST:
-		397	/* found an empty slot */
-		398	goto hit;
-		399	}
-		400	}
-		401	block_put(b);
-		402	}
-		403
-		404	/*
-		405	* We need to grow the parent in order to create a new unused dentry.
-		406	*/
-		407	futex_up(&parentp->idx->lock);
-		408	return ENOTSUP; /* XXX */
-		409
-		410	hit:
-		411	/*
-		412	* At this point we only establish the link between the parent and the
-		413	* child. The dentry, except of the name and the extension, will remain
-		414	* uninitialized until the the corresponding node is synced. Thus the
-		415	* valid dentry data is kept in the child node structure.
-		416	*/
-		417	memset(d, 0, sizeof(fat_dentry_t));
-		418	fat_dentry_name_set(d, name);
-		419	b->dirty = true; /* need to sync block */
-		420	block_put(b);
-		421	futex_up(&parentp->idx->lock);
-		422
-		423	futex_down(&childp->idx->lock);
-		424	childp->idx->pfc = parentp->firstc;
-		425	childp->idx->pdi = i * dps + j;
-		426	futex_up(&childp->idx->lock);
-		427
-		428	futex_down(&childp->lock);
-		429	childp->lnkcnt = 1;
-		430	childp->dirty = true; /* need to sync node */
-		431	futex_up(&childp->lock);
-		432
-		433	/*
-		434	* Hash in the index structure into the position hash.
-		435	*/
-		436	fat_idx_hashin(childp->idx);
-		437
-		438	return EOK;
347	}	439	}
348		440
349	int fat_unlink(void prnt, void chld)	441	int fat_unlink(void prnt, void chld)
350	{	442	{
351	return ENOTSUP; /* not supported at the moment */	443	return ENOTSUP; /* not supported at the moment */
352	}	444	}
353		445
354	void fat_match(void prnt, const char *component)	446	void fat_match(void prnt, const char *component)
355	{	447	{
356	fat_bs_t *bs;	448	fat_bs_t *bs;
357	fat_node_t parentp = (fat_node_t )prnt;	449	fat_node_t parentp = (fat_node_t )prnt;
358	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	450	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
359	unsigned i, j;	451	unsigned i, j;
360	unsigned bps; /* bytes per sector */	452	unsigned bps; /* bytes per sector */
361	unsigned dps; /* dentries per sector */	453	unsigned dps; /* dentries per sector */
362	unsigned blocks;	454	unsigned blocks;
363	fat_dentry_t *d;	455	fat_dentry_t *d;
364	block_t *b;	456	block_t *b;
365		457
366	futex_down(&parentp->idx->lock);	458	futex_down(&parentp->idx->lock);
367	bs = block_bb_get(parentp->idx->dev_handle);	459	bs = block_bb_get(parentp->idx->dev_handle);
368	bps = uint16_t_le2host(bs->bps);	460	bps = uint16_t_le2host(bs->bps);
369	dps = bps / sizeof(fat_dentry_t);	461	dps = bps / sizeof(fat_dentry_t);
370	blocks = parentp->size / bps;	462	blocks = parentp->size / bps;
371	for (i = 0; i < blocks; i++) {	463	for (i = 0; i < blocks; i++) {
372	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);	464	b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
373	for (j = 0; j < dps; j++) {	465	for (j = 0; j < dps; j++) {
374	d = ((fat_dentry_t *)b->data) + j;	466	d = ((fat_dentry_t *)b->data) + j;
375	switch (fat_classify_dentry(d)) {	467	switch (fat_classify_dentry(d)) {
376	case FAT_DENTRY_SKIP:	468	case FAT_DENTRY_SKIP:
-		469	case FAT_DENTRY_FREE:
377	continue;	470	continue;
378	case FAT_DENTRY_LAST:	471	case FAT_DENTRY_LAST:
379	block_put(b);	472	block_put(b);
380	futex_up(&parentp->idx->lock);	473	futex_up(&parentp->idx->lock);
381	return NULL;	474	return NULL;
382	default:	475	default:
383	case FAT_DENTRY_VALID:	476	case FAT_DENTRY_VALID:
384	dentry_name_canonify(d, name);	477	fat_dentry_name_get(d, name);
385	break;	478	break;
386	}	479	}
387	if (stricmp(name, component) == 0) {	480	if (stricmp(name, component) == 0) {
388	/* hit */	481	/* hit */
389	void *node;	482	void *node;
390	/*	483	/*
391	* Assume tree hierarchy for locking. We	484	* Assume tree hierarchy for locking. We
392	* already have the parent and now we are going	485	* already have the parent and now we are going
393	* to lock the child. Never lock in the oposite	486	* to lock the child. Never lock in the oposite
394	* order.	487	* order.
395	*/	488	*/
396	fat_idx_t *idx = fat_idx_get_by_pos(	489	fat_idx_t *idx = fat_idx_get_by_pos(
397	parentp->idx->dev_handle, parentp->firstc,	490	parentp->idx->dev_handle, parentp->firstc,
398	i * dps + j);	491	i * dps + j);
399	futex_up(&parentp->idx->lock);	492	futex_up(&parentp->idx->lock);
400	if (!idx) {	493	if (!idx) {
401	/*	494	/*
402	* Can happen if memory is low or if we	495	* Can happen if memory is low or if we
403	* run out of 32-bit indices.	496	* run out of 32-bit indices.
404	*/	497	*/
405	block_put(b);	498	block_put(b);
406	return NULL;	499	return NULL;
407	}	500	}

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c @ 3638 – Rev 3625 → 3628