source: mainline/uspace/srv/fs/exfat/exfat_ops.c@ e090244c

/*
 * Copyright (c) 2008 Jakub Jermar
 * Copyright (c) 2011 Oleg Romanenko
 * 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        exfat_ops.c
 * @brief       Implementation of VFS operations for the exFAT file system server.
 */

#include "exfat.h"
#include "exfat_fat.h"
#include "exfat_dentry.h"
#include "exfat_directory.h"
#include "../../vfs/vfs.h"
#include <libfs.h>
#include <libblock.h>
#include <ipc/services.h>
#include <ipc/devmap.h>
#include <macros.h>
#include <async.h>
#include <errno.h>
#include <str.h>
#include <byteorder.h>
#include <adt/hash_table.h>
#include <adt/list.h>
#include <assert.h>
#include <fibril_synch.h>
#include <sys/mman.h>
#include <align.h>
#include <malloc.h>
#include <stdio.h>

#define EXFAT_NODE(node)        ((node) ? (exfat_node_t *) (node)->data : NULL)
#define FS_NODE(node)   ((node) ? (node)->bp : NULL)
#define DPS(bs) (BPS((bs)) / sizeof(exfat_dentry_t))

/** Mutex protecting the list of cached free FAT nodes. */
static FIBRIL_MUTEX_INITIALIZE(ffn_mutex);

/** List of cached free FAT nodes. */
static LIST_INITIALIZE(ffn_list);

/*
 * Forward declarations of FAT libfs operations.
 */
/*
static int exfat_bitmap_get(fs_node_t **, devmap_handle_t);
static int exfat_uctable_get(fs_node_t **, devmap_handle_t);
*/
static int exfat_root_get(fs_node_t **, devmap_handle_t);
static int exfat_match(fs_node_t **, fs_node_t *, const char *);
static int exfat_node_get(fs_node_t **, devmap_handle_t, fs_index_t);
static int exfat_node_open(fs_node_t *);
static int exfat_node_put(fs_node_t *);
static int exfat_create_node(fs_node_t **, devmap_handle_t, int);
static int exfat_destroy_node(fs_node_t *);
static int exfat_link(fs_node_t *, fs_node_t *, const char *);
static int exfat_unlink(fs_node_t *, fs_node_t *, const char *);
static int exfat_has_children(bool *, fs_node_t *);
static fs_index_t exfat_index_get(fs_node_t *);
static aoff64_t exfat_size_get(fs_node_t *);
static unsigned exfat_lnkcnt_get(fs_node_t *);
static bool exfat_is_directory(fs_node_t *);
static bool exfat_is_file(fs_node_t *node);
static devmap_handle_t exfat_device_get(fs_node_t *node);

/*
 * Helper functions.
 */
static void exfat_node_initialize(exfat_node_t *node)
{
        fibril_mutex_initialize(&node->lock);
        node->bp = NULL;
        node->idx = NULL;
        node->type = EXFAT_UNKNOW;
        link_initialize(&node->ffn_link);
        node->size = 0;
        node->lnkcnt = 0;
        node->refcnt = 0;
        node->dirty = false;
        node->fragmented = true;
        node->lastc_cached_valid = false;
        node->lastc_cached_value = 0;
        node->currc_cached_valid = false;
        node->currc_cached_bn = 0;
        node->currc_cached_value = 0;
}

static int exfat_node_sync(exfat_node_t *node)
{
        return EOK;
}

static int exfat_node_fini_by_devmap_handle(devmap_handle_t devmap_handle)
{
        exfat_node_t *nodep;
        int rc;

        /*
         * We are called from fat_unmounted() and assume that there are already
         * no nodes belonging to this instance with non-zero refcount. Therefore
         * it is sufficient to clean up only the FAT free node list.
         */

restart:
        fibril_mutex_lock(&ffn_mutex);
        list_foreach(ffn_list, lnk) {
                nodep = list_get_instance(lnk, exfat_node_t, ffn_link);
                if (!fibril_mutex_trylock(&nodep->lock)) {
                        fibril_mutex_unlock(&ffn_mutex);
                        goto restart;
                }
                if (!fibril_mutex_trylock(&nodep->idx->lock)) {
                        fibril_mutex_unlock(&nodep->lock);
                        fibril_mutex_unlock(&ffn_mutex);
                        goto restart;
                }
                if (nodep->idx->devmap_handle != devmap_handle) {
                        fibril_mutex_unlock(&nodep->idx->lock);
                        fibril_mutex_unlock(&nodep->lock);
                        continue;
                }

                list_remove(&nodep->ffn_link);
                fibril_mutex_unlock(&ffn_mutex);

                /*
                 * We can unlock the node and its index structure because we are
                 * the last player on this playground and VFS is preventing new
                 * players from entering.
                 */
                fibril_mutex_unlock(&nodep->idx->lock);
                fibril_mutex_unlock(&nodep->lock);

                if (nodep->dirty) {
                        rc = exfat_node_sync(nodep);
                        if (rc != EOK)
                                return rc;
                }
                nodep->idx->nodep = NULL;
                free(nodep->bp);
                free(nodep);

                /* Need to restart because we changed the ffn_list. */
                goto restart;
        }
        fibril_mutex_unlock(&ffn_mutex);

        return EOK;
}

static int exfat_node_get_new(exfat_node_t **nodepp)
{
        fs_node_t *fn;
        exfat_node_t *nodep;
        int rc;

        fibril_mutex_lock(&ffn_mutex);
        if (!list_empty(&ffn_list)) {
                /* Try to use a cached free node structure. */
                exfat_idx_t *idxp_tmp;
                nodep = list_get_instance(list_first(&ffn_list), exfat_node_t,
                    ffn_link);
                if (!fibril_mutex_trylock(&nodep->lock))
                        goto skip_cache;
                idxp_tmp = nodep->idx;
                if (!fibril_mutex_trylock(&idxp_tmp->lock)) {
                        fibril_mutex_unlock(&nodep->lock);
                        goto skip_cache;
                }
                list_remove(&nodep->ffn_link);
                fibril_mutex_unlock(&ffn_mutex);
                if (nodep->dirty) {
                        rc = exfat_node_sync(nodep);
                        if (rc != EOK) {
                                idxp_tmp->nodep = NULL;
                                fibril_mutex_unlock(&nodep->lock);
                                fibril_mutex_unlock(&idxp_tmp->lock);
                                free(nodep->bp);
                                free(nodep);
                                return rc;
                        }
                }
                idxp_tmp->nodep = NULL;
                fibril_mutex_unlock(&nodep->lock);
                fibril_mutex_unlock(&idxp_tmp->lock);
                fn = FS_NODE(nodep);
        } else {
skip_cache:
                /* Try to allocate a new node structure. */
                fibril_mutex_unlock(&ffn_mutex);
                fn = (fs_node_t *)malloc(sizeof(fs_node_t));
                if (!fn)
                        return ENOMEM;
                nodep = (exfat_node_t *)malloc(sizeof(exfat_node_t));
                if (!nodep) {
                        free(fn);
                        return ENOMEM;
                }
        }
        exfat_node_initialize(nodep);
        fs_node_initialize(fn);
        fn->data = nodep;
        nodep->bp = fn;

        *nodepp = nodep;
        return EOK;
}

static int exfat_node_get_new_by_pos(exfat_node_t **nodepp, 
    devmap_handle_t devmap_handle, exfat_cluster_t pfc, unsigned pdi)
{
        exfat_idx_t *idxp = exfat_idx_get_by_pos(devmap_handle, pfc, pdi);
        if (!idxp)
                return ENOMEM;
        if (exfat_node_get_new(nodepp) != EOK)
                return ENOMEM;
        (*nodepp)->idx = idxp;
        idxp->nodep = *nodepp;
        return EOK;
}


/** Internal version of exfat_node_get().
 *
 * @param idxp          Locked index structure.
 */
static int exfat_node_get_core(exfat_node_t **nodepp, exfat_idx_t *idxp)
{
        block_t *b=NULL;
        exfat_bs_t *bs;
        exfat_dentry_t *d;
        exfat_node_t *nodep = NULL;
        int rc;

        if (idxp->nodep) {
                /*
                 * We are lucky.
                 * The node is already instantiated in memory.
                 */
                fibril_mutex_lock(&idxp->nodep->lock);
                if (!idxp->nodep->refcnt++) {
                        fibril_mutex_lock(&ffn_mutex);
                        list_remove(&idxp->nodep->ffn_link);
                        fibril_mutex_unlock(&ffn_mutex);
                }
                fibril_mutex_unlock(&idxp->nodep->lock);
                *nodepp = idxp->nodep;
                return EOK;
        }

        /*
         * We must instantiate the node from the file system.
         */

        assert(idxp->pfc);

        rc = exfat_node_get_new(&nodep);
        if (rc != EOK)
                return rc;

        bs = block_bb_get(idxp->devmap_handle);

        rc = exfat_block_get_by_clst(&b, bs, idxp->devmap_handle, 
            idxp->parent_fragmented, idxp->pfc, NULL, 
            (idxp->pdi * sizeof(exfat_dentry_t)) / BPS(bs), BLOCK_FLAGS_NONE);
        if (rc != EOK) {
                (void) exfat_node_put(FS_NODE(nodep));
                return rc;
        }

        d = ((exfat_dentry_t *)b->data) + (idxp->pdi % DPS(bs));
        switch (exfat_classify_dentry(d)) {
        case EXFAT_DENTRY_FILE:
                nodep->type = (d->file.attr & EXFAT_ATTR_SUBDIR)? 
                    EXFAT_DIRECTORY : EXFAT_FILE;
                rc = block_put(b);
                if (rc != EOK) {
                        (void) exfat_node_put(FS_NODE(nodep));
                        return rc;
                }
                rc = exfat_block_get_by_clst(&b, bs, idxp->devmap_handle, 
                        idxp->parent_fragmented, idxp->pfc, NULL, 
                        ((idxp->pdi+1) * sizeof(exfat_dentry_t)) / BPS(bs), BLOCK_FLAGS_NONE);
                if (rc != EOK) {
                        (void) exfat_node_put(FS_NODE(nodep));
                        return rc;
                }
                d = ((exfat_dentry_t *)b->data) + ((idxp->pdi+1) % DPS(bs));
                
                nodep->firstc = d->stream.firstc;
                nodep->size = d->stream.data_size;
                nodep->fragmented = (d->stream.flags & 0x02) == 0;
                break;
        case EXFAT_DENTRY_BITMAP:
                nodep->type = EXFAT_BITMAP;
                nodep->firstc = d->bitmap.firstc;
                nodep->size = d->bitmap.size;
                nodep->fragmented = true;
                break;
        case EXFAT_DENTRY_UCTABLE:
                nodep->type = EXFAT_UCTABLE;
                nodep->firstc = d->uctable.firstc;
                nodep->size = d->uctable.size;
                nodep->fragmented = true;
                break;
        default:
        case EXFAT_DENTRY_SKIP:
        case EXFAT_DENTRY_LAST:
        case EXFAT_DENTRY_FREE:
        case EXFAT_DENTRY_VOLLABEL:
        case EXFAT_DENTRY_GUID:
        case EXFAT_DENTRY_STREAM:
        case EXFAT_DENTRY_NAME:
                (void) block_put(b);
                (void) exfat_node_put(FS_NODE(nodep));
                return ENOENT;
        }

        nodep->lnkcnt = 1;
        nodep->refcnt = 1;

        rc = block_put(b);
        if (rc != EOK) {
                (void) exfat_node_put(FS_NODE(nodep));
                return rc;
        }

        /* Link the idx structure with the node structure. */
        nodep->idx = idxp;
        idxp->nodep = nodep;

        *nodepp = nodep;
        return EOK;
}



/*
 * EXFAT libfs operations.
 */

int exfat_root_get(fs_node_t **rfn, devmap_handle_t devmap_handle)
{
        return exfat_node_get(rfn, devmap_handle, EXFAT_ROOT_IDX);
}

/*
int exfat_bitmap_get(fs_node_t **rfn, devmap_handle_t devmap_handle)
{
        return exfat_node_get(rfn, devmap_handle, EXFAT_BITMAP_IDX);
}
*/
/*
int exfat_uctable_get(fs_node_t **rfn, devmap_handle_t devmap_handle)
{
        return exfat_node_get(rfn, devmap_handle, EXFAT_UCTABLE_IDX);
}
*/

int exfat_match(fs_node_t **rfn, fs_node_t *pfn, const char *component)
{
        exfat_node_t *parentp = EXFAT_NODE(pfn);
        char name[EXFAT_FILENAME_LEN+1];
        exfat_file_dentry_t df;
        exfat_stream_dentry_t ds;
        devmap_handle_t devmap_handle;
        int rc;

        fibril_mutex_lock(&parentp->idx->lock);
        devmap_handle = parentp->idx->devmap_handle;
        fibril_mutex_unlock(&parentp->idx->lock);
        
        exfat_directory_t di;
        rc = exfat_directory_open(parentp, &di);
        if (rc != EOK)
                return rc;

        while (exfat_directory_read_file(&di, name, EXFAT_FILENAME_LEN, 
            &df, &ds) == EOK) {
                if (stricmp(name, component) == 0) {
                        /* hit */
                        exfat_node_t *nodep;
                        aoff64_t o = di.pos % (BPS(di.bs) / sizeof(exfat_dentry_t));
                        exfat_idx_t *idx = exfat_idx_get_by_pos(devmap_handle,
                                parentp->firstc, di.bnum * DPS(di.bs) + o);
                        if (!idx) {
                                /*
                                 * Can happen if memory is low or if we
                                 * run out of 32-bit indices.
                                 */
                                rc = exfat_directory_close(&di);
                                return (rc == EOK) ? ENOMEM : rc;
                        }
                        rc = exfat_node_get_core(&nodep, idx);
                        fibril_mutex_unlock(&idx->lock);
                        if (rc != EOK) {
                                (void) exfat_directory_close(&di);
                                return rc;
                        }
                        *rfn = FS_NODE(nodep);
                        rc = exfat_directory_close(&di);
                        if (rc != EOK)
                                (void) exfat_node_put(*rfn);
                        return rc;
                } else {
                        rc = exfat_directory_next(&di);
                        if (rc != EOK)
                                break;
                }
        }
        (void) exfat_directory_close(&di);
        *rfn = NULL;
        return EOK;
}

/** Instantiate a exFAT in-core node. */
int exfat_node_get(fs_node_t **rfn, devmap_handle_t devmap_handle, fs_index_t index)
{
        exfat_node_t *nodep;
        exfat_idx_t *idxp;
        int rc;

        idxp = exfat_idx_get_by_index(devmap_handle, index);
        if (!idxp) {
                *rfn = NULL;
                return EOK;
        }
        /* idxp->lock held */
        rc = exfat_node_get_core(&nodep, idxp);
        fibril_mutex_unlock(&idxp->lock);
        if (rc == EOK)
                *rfn = FS_NODE(nodep);
        return rc;
}

int exfat_node_open(fs_node_t *fn)
{
        /*
         * Opening a file is stateless, nothing
         * to be done here.
         */
        return EOK;
}

int exfat_node_put(fs_node_t *fn)
{
        exfat_node_t *nodep = EXFAT_NODE(fn);
        bool destroy = false;

        fibril_mutex_lock(&nodep->lock);
        if (!--nodep->refcnt) {
                if (nodep->idx) {
                        fibril_mutex_lock(&ffn_mutex);
                        list_append(&nodep->ffn_link, &ffn_list);
                        fibril_mutex_unlock(&ffn_mutex);
                } 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;
                }
        }
        fibril_mutex_unlock(&nodep->lock);
        if (destroy) {
                free(nodep->bp);
                free(nodep);
        }
        return EOK;
}

int exfat_create_node(fs_node_t **rfn, devmap_handle_t devmap_handle, int flags)
{
        /* TODO */
        *rfn = NULL;
        return EOK;
}

int exfat_destroy_node(fs_node_t *fn)
{
        /* TODO */
        return EOK;
}

int exfat_link(fs_node_t *pfn, fs_node_t *cfn, const char *name)
{
        /* TODO */
        return EOK;
}

int exfat_unlink(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
{
        /* TODO */
        return EOK;
}

int exfat_has_children(bool *has_children, fs_node_t *fn)
{
        exfat_directory_t di;
        exfat_dentry_t *d;
        exfat_node_t *nodep = EXFAT_NODE(fn);
        int rc;

        *has_children = false;

        if (nodep->type != EXFAT_DIRECTORY)
                return EOK;

        fibril_mutex_lock(&nodep->idx->lock);

        rc = exfat_directory_open(nodep, &di);
        if (rc != EOK) {
                fibril_mutex_unlock(&nodep->idx->lock);
                return rc;
        }

        do {
                rc = exfat_directory_get(&di, &d);
                if (rc != EOK) {
                        (void) exfat_directory_close(&di);
                        fibril_mutex_unlock(&nodep->idx->lock);
                        return rc;
                }
                switch (exfat_classify_dentry(d)) {
                case EXFAT_DENTRY_SKIP:
                case EXFAT_DENTRY_FREE:
                        continue;
                case EXFAT_DENTRY_LAST:
                        *has_children = false;
                        goto exit;
                default:
                        *has_children = true;
                        goto exit;
                }
        } while (exfat_directory_next(&di) == EOK);

exit:
        rc = exfat_directory_close(&di);
        fibril_mutex_unlock(&nodep->idx->lock);
        return rc;
}


fs_index_t exfat_index_get(fs_node_t *fn)
{
        return EXFAT_NODE(fn)->idx->index;
}

aoff64_t exfat_size_get(fs_node_t *fn)
{
        return EXFAT_NODE(fn)->size;
}

unsigned exfat_lnkcnt_get(fs_node_t *fn)
{
        return EXFAT_NODE(fn)->lnkcnt;
}

bool exfat_is_directory(fs_node_t *fn)
{
        return EXFAT_NODE(fn)->type == EXFAT_DIRECTORY;
}

bool exfat_is_file(fs_node_t *fn)
{
        return EXFAT_NODE(fn)->type == EXFAT_FILE;
}

devmap_handle_t exfat_device_get(fs_node_t *node)
{
        return 0;
}


/** libfs operations */
libfs_ops_t exfat_libfs_ops = {
        .root_get = exfat_root_get,
        .match = exfat_match,
        .node_get = exfat_node_get,
        .node_open = exfat_node_open,
        .node_put = exfat_node_put,
        .create = exfat_create_node,
        .destroy = exfat_destroy_node,
        .link = exfat_link,
        .unlink = exfat_unlink,
        .has_children = exfat_has_children,
        .index_get = exfat_index_get,
        .size_get = exfat_size_get,
        .lnkcnt_get = exfat_lnkcnt_get,
        .is_directory = exfat_is_directory,
        .is_file = exfat_is_file,
        .device_get = exfat_device_get
};


/*
 * VFS_OUT operations.
 */

/* Print debug info */
static void exfat_fsinfo(exfat_bs_t *bs, devmap_handle_t devmap_handle)
{
        printf("exFAT file system mounted\n");
        printf("Version: %d.%d\n", bs->version.major, bs->version.minor);
        printf("Volume serial: %d\n", uint32_t_le2host(bs->volume_serial));
        printf("Volume first sector: %lld\n", VOL_FS(bs));
        printf("Volume sectors: %lld\n", VOL_CNT(bs));
        printf("FAT first sector: %d\n", FAT_FS(bs));
        printf("FAT sectors: %d\n", FAT_CNT(bs));
        printf("Data first sector: %d\n", DATA_FS(bs));
        printf("Data sectors: %d\n", DATA_CNT(bs));
        printf("Root dir first cluster: %d\n", ROOT_FC(bs));
        printf("Bytes per sector: %d\n", BPS(bs));
        printf("Sectors per cluster: %d\n", SPC(bs));
        printf("KBytes per cluster: %d\n", SPC(bs)*BPS(bs)/1024);
        
        int i, rc;
        exfat_cluster_t clst;
        for (i=0; i<6; i++) {
                rc = fat_get_cluster(bs, devmap_handle, i, &clst);
                if (rc != EOK)
                        return;
                printf("Clst %d: %x\n", i, clst);
        }
}

static int
exfat_mounted(devmap_handle_t devmap_handle, const char *opts, fs_index_t *index,
    aoff64_t *size, unsigned *linkcnt)
{
        int rc;
        exfat_node_t *rootp=NULL, *bitmapp=NULL, *uctablep=NULL;
        enum cache_mode cmode;
        exfat_bs_t *bs;

        /* Check for option enabling write through. */
        if (str_cmp(opts, "wtcache") == 0)
                cmode = CACHE_MODE_WT;
        else
                cmode = CACHE_MODE_WB;

        /* initialize libblock */
        rc = block_init(EXCHANGE_SERIALIZE, devmap_handle, BS_SIZE);
        if (rc != EOK)
                return rc;

        /* prepare the boot block */
        rc = block_bb_read(devmap_handle, BS_BLOCK);
        if (rc != EOK) {
                block_fini(devmap_handle);
                return rc;
        }

        /* get the buffer with the boot sector */
        bs = block_bb_get(devmap_handle);

        /* Initialize the block cache */
        rc = block_cache_init(devmap_handle, BPS(bs), 0 /* XXX */, cmode);
        if (rc != EOK) {
                block_fini(devmap_handle);
                return rc;
        }

        /* Do some simple sanity checks on the file system. */
        rc = exfat_sanity_check(bs, devmap_handle);
        if (rc != EOK) {
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                return rc;
        }

        rc = exfat_idx_init_by_devmap_handle(devmap_handle);
        if (rc != EOK) {
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                return rc;
        }

        /* Initialize the root node. */
        rc = exfat_node_get_new_by_pos(&rootp, devmap_handle, EXFAT_ROOT_PAR, 
            EXFAT_ROOT_POS);
        if (rc!=EOK) {
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOMEM;
        }
        assert(rootp->idx->index == EXFAT_ROOT_IDX);

        rootp->type = EXFAT_DIRECTORY;
        rootp->firstc = ROOT_FC(bs);
        rootp->fragmented = true;
        rootp->refcnt = 1;
        rootp->lnkcnt = 0;      /* FS root is not linked */

        uint32_t clusters;
        rc = fat_clusters_get(&clusters, bs, devmap_handle, rootp->firstc);
        if (rc != EOK) {
                free(rootp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOTSUP;
        }
        rootp->size = BPS(bs) * SPC(bs) * clusters;
        fibril_mutex_unlock(&rootp->idx->lock);

        /* Open root directory and looking for Bitmap and UC-Table */
        exfat_directory_t di;
        exfat_dentry_t *de;
        rc = exfat_directory_open(rootp, &di);
        if (rc != EOK) {
                free(rootp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOTSUP;
        }

        /* Initialize the bitmap node. */
        rc = exfat_directory_find(&di, EXFAT_DENTRY_BITMAP, &de);
        if (rc != EOK) {
                free(rootp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOTSUP;
        }

        rc = exfat_node_get_new_by_pos(&bitmapp, devmap_handle, rootp->firstc, 
            di.pos);
        if (rc!=EOK) {
                free(rootp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOMEM;
        }
        assert(bitmapp->idx->index == EXFAT_BITMAP_IDX);
        fibril_mutex_unlock(&bitmapp->idx->lock);

        bitmapp->type = EXFAT_BITMAP;
        bitmapp->firstc = de->bitmap.firstc;
        bitmapp->fragmented = true;
        bitmapp->idx->parent_fragmented = true;
        bitmapp->refcnt = 1;
        bitmapp->lnkcnt = 0;
        bitmapp->size = de->bitmap.size;

        /* Initialize the uctable node. */
        rc = exfat_directory_seek(&di, 0);
        if (rc != EOK) {
                free(rootp);
                free(bitmapp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOTSUP;
        }

        rc = exfat_directory_find(&di, EXFAT_DENTRY_UCTABLE, &de);
        if (rc != EOK) {
                free(rootp);
                free(bitmapp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOTSUP;
        }

        rc = exfat_node_get_new_by_pos(&uctablep, devmap_handle, rootp->firstc, 
            di.pos);
        if (rc!=EOK) {
                free(rootp);
                free(bitmapp);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOMEM;
        }
        assert(uctablep->idx->index == EXFAT_UCTABLE_IDX);
        fibril_mutex_unlock(&uctablep->idx->lock);

        uctablep->type = EXFAT_UCTABLE;
        uctablep->firstc = de->uctable.firstc;
        uctablep->fragmented = true;
        uctablep->idx->parent_fragmented = true;
        uctablep->refcnt = 1;
        uctablep->lnkcnt = 0;
        uctablep->size = de->uctable.size;

        rc = exfat_directory_close(&di);
        if (rc!=EOK) {
                free(rootp);
                free(bitmapp);
                free(uctablep);
                (void) block_cache_fini(devmap_handle);
                block_fini(devmap_handle);
                exfat_idx_fini_by_devmap_handle(devmap_handle);
                return ENOMEM;
        }

        exfat_fsinfo(bs, devmap_handle);
        printf("Root dir size: %lld\n", rootp->size);

        *index = rootp->idx->index;
        *size = rootp->size;
        *linkcnt = rootp->lnkcnt;
        
        return EOK;
}

static int exfat_unmounted(devmap_handle_t devmap_handle)
{
        fs_node_t *fn;
        exfat_node_t *nodep;
        int rc;

        rc = exfat_root_get(&fn, devmap_handle);
        if (rc != EOK)
                return rc;
        nodep = EXFAT_NODE(fn);

        /*
         * We expect exactly two references on the root node. One for the
         * fat_root_get() above and one created in fat_mounted().
         */
        if (nodep->refcnt != 2) {
                (void) exfat_node_put(fn);
                return EBUSY;
        }

        /*
         * Put the root node and force it to the FAT free node list.
         */
        (void) exfat_node_put(fn);
        (void) exfat_node_put(fn);

        /*
         * Perform cleanup of the node structures, index structures and
         * associated data. Write back this file system's dirty blocks and
         * stop using libblock for this instance.
         */
        (void) exfat_node_fini_by_devmap_handle(devmap_handle);
        exfat_idx_fini_by_devmap_handle(devmap_handle);
        (void) block_cache_fini(devmap_handle);
        block_fini(devmap_handle);

        return EOK;
}

/*
int bitmap_is_allocated(exfat_bs_t *bs, devmap_handle_t devmap_handle,
    exfat_cluster_t clst, bool *status)
{
        fs_node_t *fn;
        exfat_node_t *bitmap;
        int rc;

        rc = exfat_bitmap_get(&fn, devmap_handle);
        if (rc != EOK)
                return rc;

        nbitmap = EXFAT_NODE(fn);

        
        return EOK;
}
*/

static int
exfat_read(devmap_handle_t devmap_handle, fs_index_t index, aoff64_t pos,
    size_t *rbytes)
{
        fs_node_t *fn;
        exfat_node_t *nodep;
        exfat_bs_t *bs;
        size_t bytes=0;
        block_t *b;
        int rc;

        rc = exfat_node_get(&fn, devmap_handle, index);
        if (rc != EOK)
                return rc;
        if (!fn)
                return ENOENT;
        nodep = EXFAT_NODE(fn);

        ipc_callid_t callid;
        size_t len;
        if (!async_data_read_receive(&callid, &len)) {
                exfat_node_put(fn);
                async_answer_0(callid, EINVAL);
                return EINVAL;
        }

        bs = block_bb_get(devmap_handle);

        if (nodep->type == EXFAT_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) async_data_read_finalize(callid, NULL, 0);
                } else {
                        bytes = min(len, BPS(bs) - pos % BPS(bs));
                        bytes = min(bytes, nodep->size - pos);
                        rc = exfat_block_get(&b, bs, nodep, pos / BPS(bs),
                            BLOCK_FLAGS_NONE);
                        if (rc != EOK) {
                                exfat_node_put(fn);
                                async_answer_0(callid, rc);
                                return rc;
                        }
                        (void) async_data_read_finalize(callid,
                            b->data + pos % BPS(bs), bytes);
                        rc = block_put(b);
                        if (rc != EOK) {
                                exfat_node_put(fn);
                                return rc;
                        }
                }
        } else {
                if (nodep->type != EXFAT_DIRECTORY) {
                        async_answer_0(callid, ENOTSUP);
                        return ENOTSUP;
                }
                        
                aoff64_t spos = pos;
                char name[EXFAT_FILENAME_LEN+1];
                exfat_file_dentry_t df;
                exfat_stream_dentry_t ds;

                assert(nodep->size % BPS(bs) == 0);
                assert(BPS(bs) % sizeof(exfat_dentry_t) == 0);

                exfat_directory_t di;
                rc = exfat_directory_open(nodep, &di);
                if (rc != EOK) goto err;
                rc = exfat_directory_seek(&di, pos);
                if (rc != EOK) {
                        (void) exfat_directory_close(&di);
                        goto err;
                }

                rc = exfat_directory_read_file(&di, name, EXFAT_FILENAME_LEN, &df, &ds);
                if (rc == EOK) goto hit;
                if (rc == ENOENT) goto miss;

err:
                (void) exfat_node_put(fn);
                async_answer_0(callid, rc);
                return rc;

miss:
                rc = exfat_directory_close(&di);
                if (rc!=EOK)
                        goto err;
                rc = exfat_node_put(fn);
                async_answer_0(callid, rc != EOK ? rc : ENOENT);
                *rbytes = 0;
                return rc != EOK ? rc : ENOENT;

hit:
                pos = di.pos;
                rc = exfat_directory_close(&di);
                if (rc!=EOK)
                        goto err;
                (void) async_data_read_finalize(callid, name, str_size(name) + 1);
                bytes = (pos - spos)+1;
        }

        rc = exfat_node_put(fn);
        *rbytes = bytes;
        return rc;
}

static int exfat_close(devmap_handle_t devmap_handle, fs_index_t index)
{
        return EOK;
}

static int exfat_sync(devmap_handle_t devmap_handle, fs_index_t index)
{
        fs_node_t *fn;
        int rc = exfat_node_get(&fn, devmap_handle, index);
        if (rc != EOK)
                return rc;
        if (!fn)
                return ENOENT;

        exfat_node_t *nodep = EXFAT_NODE(fn);

        nodep->dirty = true;
        rc = exfat_node_sync(nodep);

        exfat_node_put(fn);
        return rc;
}

static int
exfat_write(devmap_handle_t devmap_handle, fs_index_t index, aoff64_t pos,
    size_t *wbytes, aoff64_t *nsize)
{
        /* TODO */
        return EOK;
}

static int
exfat_truncate(devmap_handle_t devmap_handle, fs_index_t index, aoff64_t size)
{
        /* TODO */
        return EOK;
}
static int exfat_destroy(devmap_handle_t devmap_handle, fs_index_t index)
{
        /* TODO */
        return EOK;
}

vfs_out_ops_t exfat_ops = {
        .mounted = exfat_mounted,
        .unmounted = exfat_unmounted,
        .read = exfat_read,
        .write = exfat_write,
        .truncate = exfat_truncate,
        .close = exfat_close,
        .destroy = exfat_destroy,
        .sync = exfat_sync,
};


/**
 * @}
 */