source: rtems/cpukit/libfs/src/jffs2/src/fs-rtems.c @ eb77534

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2003 Free Software Foundation, Inc.
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 * Copyright © 2013 embedded brains GmbH <rtems@embedded-brains.de>
 *
 * Created by Dominic Ostrowski <dominic.ostrowski@3glab.com>
 * Contributors: David Woodhouse, Nick Garnett, Richard Panton.
 *
 * Port to the RTEMS by embedded brains GmbH.
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: fs-ecos.c,v 1.44 2005/07/24 15:29:57 dedekind Exp $
 *
 */

#include <linux/kernel.h>
#include "nodelist.h"
#include <linux/pagemap.h>
#include <linux/crc32.h>
#include "compr.h"
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <rtems/libio.h>
#include <rtems/libio_.h>

/* Ensure that the JFFS2 values are identical to the POSIX defines */

RTEMS_STATIC_ASSERT(DT_DIR == (S_IFDIR >> 12), DT_DIR);
RTEMS_STATIC_ASSERT(DT_LNK == (S_IFLNK >> 12), DT_LNK);
RTEMS_STATIC_ASSERT(DT_REG == (S_IFREG >> 12), DT_REG);

RTEMS_STATIC_ASSERT(00400 == S_IRUSR, S_IRUSR);
RTEMS_STATIC_ASSERT(00200 == S_IWUSR, S_IWUSR);
RTEMS_STATIC_ASSERT(00100 == S_IXUSR, S_IXUSR);
RTEMS_STATIC_ASSERT(00040 == S_IRGRP, S_IRGRP);
RTEMS_STATIC_ASSERT(00020 == S_IWGRP, S_IWGRP);
RTEMS_STATIC_ASSERT(00010 == S_IXGRP, S_IXGRP);
RTEMS_STATIC_ASSERT(00004 == S_IROTH, S_IROTH);
RTEMS_STATIC_ASSERT(00002 == S_IWOTH, S_IWOTH);
RTEMS_STATIC_ASSERT(00001 == S_IXOTH, S_IXOTH);

RTEMS_STATIC_ASSERT(0140000 == S_IFSOCK, S_IFSOCK);
RTEMS_STATIC_ASSERT(0120000 == S_IFLNK, S_IFLNK);
RTEMS_STATIC_ASSERT(0100000 == S_IFREG, S_IFREG);
RTEMS_STATIC_ASSERT(0060000 == S_IFBLK, S_IFBLK);
RTEMS_STATIC_ASSERT(0040000 == S_IFDIR, S_IFDIR);
RTEMS_STATIC_ASSERT(0020000 == S_IFCHR, S_IFCHR);
RTEMS_STATIC_ASSERT(0010000 == S_IFIFO, S_IFIFO);
RTEMS_STATIC_ASSERT(0004000 == S_ISUID, S_ISUID);
RTEMS_STATIC_ASSERT(0002000 == S_ISGID, S_ISGID);
RTEMS_STATIC_ASSERT(0001000 == S_ISVTX, S_ISVTX);

static int jffs2_read_inode (struct _inode *inode);
static void jffs2_clear_inode (struct _inode *inode);

//==========================================================================
// Ref count and nlink management


// FIXME: This seems like real cruft. Wouldn't it be better just to do the
// right thing?
static void icache_evict(struct _inode *root_i, struct _inode *i)
{
        struct _inode *this = root_i, *next;

 restart:
        D2(printf("icache_evict\n"));
        // If this is an absolute search path from the root,
        // remove all cached inodes with i_count of zero (these are only 
        // held where needed for dotdot filepaths)
        while (this) {
                next = this->i_cache_next;
                if (this != i && this->i_count == 0) {
                        struct _inode *parent = this->i_parent;
                        if (this->i_cache_next)
                                this->i_cache_next->i_cache_prev = this->i_cache_prev;
                        if (this->i_cache_prev)
                                this->i_cache_prev->i_cache_next = this->i_cache_next;
                        jffs2_clear_inode(this);
                        memset(this, 0x5a, sizeof(*this));
                        free(this);
                        if (parent && parent != this) {
                                parent->i_count--;
                                this = root_i;
                                goto restart;
                        }
                }
                this = next;
        }
}

// -------------------------------------------------------------------------
// jffs2_fo_write()
// Write data to file.
static int jffs2_extend_file (struct _inode *inode, struct jffs2_raw_inode *ri,
                       unsigned long offset)
{
        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct jffs2_full_dnode *fn;
        uint32_t alloc_len;
        int ret = 0;

        /* Make new hole frag from old EOF to new page */
        D1(printk(KERN_DEBUG "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
                  (unsigned int)inode->i_size, offset));

        ret = jffs2_reserve_space(c, sizeof(*ri), &alloc_len, ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
        if (ret)
                return ret;

        mutex_lock(&f->sem);

        ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
        ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
        ri->totlen = cpu_to_je32(sizeof(*ri));
        ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

        ri->version = cpu_to_je32(++f->highest_version);
        ri->isize = cpu_to_je32(max((uint32_t)inode->i_size, offset));

        ri->offset = cpu_to_je32(inode->i_size);
        ri->dsize = cpu_to_je32(offset - inode->i_size);
        ri->csize = cpu_to_je32(0);
        ri->compr = JFFS2_COMPR_ZERO;
        ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
        ri->data_crc = cpu_to_je32(0);
                
        fn = jffs2_write_dnode(c, f, ri, NULL, 0, ALLOC_NORMAL);
        jffs2_complete_reservation(c);
        if (IS_ERR(fn)) {
                ret = PTR_ERR(fn);
                mutex_unlock(&f->sem);
                return ret;
        }
        ret = jffs2_add_full_dnode_to_inode(c, f, fn);
        if (f->metadata) {
                jffs2_mark_node_obsolete(c, f->metadata->raw);
                jffs2_free_full_dnode(f->metadata);
                f->metadata = NULL;
        }
        if (ret) {
                D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in prepare_write, returned %d\n", ret));
                jffs2_mark_node_obsolete(c, fn->raw);
                jffs2_free_full_dnode(fn);
                mutex_unlock(&f->sem);
                return ret;
        }
        inode->i_size = offset;
        mutex_unlock(&f->sem);
        return 0;
}

static int jffs2_do_setattr (struct _inode *inode, struct iattr *iattr)
{
        struct jffs2_full_dnode *old_metadata, *new_metadata;
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
        struct jffs2_raw_inode *ri;
        unsigned char *mdata = NULL;
        int mdatalen = 0;
        unsigned int ivalid;
        uint32_t alloclen;
        int ret;
        int alloc_type = ALLOC_NORMAL;

        jffs2_dbg(1, "%s(): ino #%lu\n", __func__, inode->i_ino);

        /* Special cases - we don't want more than one data node
           for these types on the medium at any time. So setattr
           must read the original data associated with the node
           (i.e. the device numbers or the target name) and write
           it out again with the appropriate data attached */
        if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
                return -EIO;
        } else if (S_ISLNK(inode->i_mode)) {
                mutex_lock(&f->sem);
                mdatalen = f->metadata->size;
                mdata = kmalloc(f->metadata->size, GFP_USER);
                if (!mdata) {
                        mutex_unlock(&f->sem);
                        return -ENOMEM;
                }
                ret = jffs2_read_dnode(c, f, f->metadata, mdata, 0, mdatalen);
                if (ret) {
                        mutex_unlock(&f->sem);
                        kfree(mdata);
                        return ret;
                }
                mutex_unlock(&f->sem);
                jffs2_dbg(1, "%s(): Writing %d bytes of symlink target\n",
                          __func__, mdatalen);
        }

        ri = jffs2_alloc_raw_inode();
        if (!ri) {
                if (S_ISLNK(inode->i_mode))
                        kfree(mdata);
                return -ENOMEM;
        }

        ret = jffs2_reserve_space(c, sizeof(*ri) + mdatalen, &alloclen,
                                  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
        if (ret) {
                jffs2_free_raw_inode(ri);
                if (S_ISLNK(inode->i_mode))
                         kfree(mdata);
                return ret;
        }
        mutex_lock(&f->sem);
        ivalid = iattr->ia_valid;

        ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
        ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
        ri->totlen = cpu_to_je32(sizeof(*ri) + mdatalen);
        ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

        ri->ino = cpu_to_je32(inode->i_ino);
        ri->version = cpu_to_je32(++f->highest_version);

        ri->uid = cpu_to_je16((ivalid & ATTR_UID)?
                from_kuid(&init_user_ns, iattr->ia_uid):i_uid_read(inode));
        ri->gid = cpu_to_je16((ivalid & ATTR_GID)?
                from_kgid(&init_user_ns, iattr->ia_gid):i_gid_read(inode));

        if (ivalid & ATTR_MODE)
                ri->mode = cpu_to_jemode(iattr->ia_mode);
        else
                ri->mode = cpu_to_jemode(inode->i_mode);


        ri->isize = cpu_to_je32((ivalid & ATTR_SIZE)?iattr->ia_size:inode->i_size);
        ri->atime = cpu_to_je32(I_SEC((ivalid & ATTR_ATIME)?iattr->ia_atime:inode->i_atime));
        ri->mtime = cpu_to_je32(I_SEC((ivalid & ATTR_MTIME)?iattr->ia_mtime:inode->i_mtime));
        ri->ctime = cpu_to_je32(I_SEC((ivalid & ATTR_CTIME)?iattr->ia_ctime:inode->i_ctime));

        ri->offset = cpu_to_je32(0);
        ri->csize = ri->dsize = cpu_to_je32(mdatalen);
        ri->compr = JFFS2_COMPR_NONE;
        if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
                /* It's an extension. Make it a hole node */
                ri->compr = JFFS2_COMPR_ZERO;
                ri->dsize = cpu_to_je32(iattr->ia_size - inode->i_size);
                ri->offset = cpu_to_je32(inode->i_size);
        } else if (ivalid & ATTR_SIZE && !iattr->ia_size) {
                /* For truncate-to-zero, treat it as deletion because
                   it'll always be obsoleting all previous nodes */
                alloc_type = ALLOC_DELETION;
        }
        ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
        if (mdatalen)
                ri->data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
        else
                ri->data_crc = cpu_to_je32(0);

        new_metadata = jffs2_write_dnode(c, f, ri, mdata, mdatalen, alloc_type);
        if (S_ISLNK(inode->i_mode))
                kfree(mdata);

        if (IS_ERR(new_metadata)) {
                jffs2_complete_reservation(c);
                jffs2_free_raw_inode(ri);
                mutex_unlock(&f->sem);
                return PTR_ERR(new_metadata);
        }
        /* It worked. Update the inode */
        inode->i_atime = ITIME(je32_to_cpu(ri->atime));
        inode->i_ctime = ITIME(je32_to_cpu(ri->ctime));
        inode->i_mtime = ITIME(je32_to_cpu(ri->mtime));
        inode->i_mode = jemode_to_cpu(ri->mode);
        i_uid_write(inode, je16_to_cpu(ri->uid));
        i_gid_write(inode, je16_to_cpu(ri->gid));


        old_metadata = f->metadata;

        if (ivalid & ATTR_SIZE && inode->i_size > iattr->ia_size)
                jffs2_truncate_fragtree (c, &f->fragtree, iattr->ia_size);

        if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
                jffs2_add_full_dnode_to_inode(c, f, new_metadata);
                inode->i_size = iattr->ia_size;
                f->metadata = NULL;
        } else {
                f->metadata = new_metadata;
        }
        if (old_metadata) {
                jffs2_mark_node_obsolete(c, old_metadata->raw);
                jffs2_free_full_dnode(old_metadata);
        }
        jffs2_free_raw_inode(ri);

        mutex_unlock(&f->sem);
        jffs2_complete_reservation(c);

        /* We have to do the truncate_setsize() without f->sem held, since
           some pages may be locked and waiting for it in readpage().
           We are protected from a simultaneous write() extending i_size
           back past iattr->ia_size, because do_truncate() holds the
           generic inode semaphore. */
        if (ivalid & ATTR_SIZE && inode->i_size > iattr->ia_size) {
                truncate_setsize(inode, iattr->ia_size);
        }       

        return 0;
}

typedef struct {
        struct super_block sb;
        struct jffs2_inode_cache *inode_cache[];
} rtems_jffs2_fs_info;

static void rtems_jffs2_do_lock(const struct super_block *sb)
{
        rtems_status_code sc = rtems_semaphore_obtain(sb->s_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
        assert(sc == RTEMS_SUCCESSFUL);
        (void) sc; /* avoid unused variable warning */
}

static void rtems_jffs2_do_unlock(const struct super_block *sb)
{
        rtems_status_code sc = rtems_semaphore_release(sb->s_mutex);
        assert(sc == RTEMS_SUCCESSFUL);
        (void) sc; /* avoid unused variable warning */
}

static void rtems_jffs2_free_directory_entries(struct _inode *inode)
{
        struct jffs2_full_dirent *current = inode->jffs2_i.dents;

        while (current != NULL) {
                struct jffs2_full_dirent *victim = current;

                current = victim->next;
                jffs2_free_full_dirent(victim);
        }
}

static void rtems_jffs2_flash_control_destroy(rtems_jffs2_flash_control *fc)
{
        if (fc->destroy != NULL) {
                (*fc->destroy)(fc);
        }
}
static void rtems_jffs2_compressor_control_destroy(rtems_jffs2_compressor_control *cc)
{
        if (cc != NULL && cc->destroy != NULL) {
                (*cc->destroy)(cc);
        }
}


static void rtems_jffs2_free_fs_info(rtems_jffs2_fs_info *fs_info, bool do_mount_fs_was_successful)
{
        struct super_block *sb = &fs_info->sb;
        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);

        if (do_mount_fs_was_successful) {
                jffs2_free_ino_caches(c);
                jffs2_free_raw_node_refs(c);
                free(c->blocks);
        }

        if (sb->s_mutex != 0) {
                rtems_status_code sc = rtems_semaphore_delete(sb->s_mutex);
                assert(sc == RTEMS_SUCCESSFUL);
                (void) sc; /* avoid unused variable warning */
        }

        rtems_jffs2_flash_control_destroy(fs_info->sb.s_flash_control);
        rtems_jffs2_compressor_control_destroy(fs_info->sb.s_compressor_control);

        free(fs_info);
}

static int rtems_jffs2_eno_to_rv_and_errno(int eno)
{
        if (eno == 0) {
                return 0;
        } else {
                errno = eno;

                return -1;
        }
}

static struct _inode *rtems_jffs2_get_inode_by_location(
        const rtems_filesystem_location_info_t *loc
)
{
        return loc->node_access;
}

static struct _inode *rtems_jffs2_get_inode_by_iop(
        const rtems_libio_t *iop
)
{
        return iop->pathinfo.node_access;
}

static int rtems_jffs2_fstat(
        const rtems_filesystem_location_info_t *loc,
        struct stat *buf
)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);
        struct super_block *sb = inode->i_sb;
        rtems_jffs2_flash_control *fc = sb->s_flash_control;

        rtems_jffs2_do_lock(sb);

        buf->st_dev = fc->device_identifier;
        buf->st_blksize = PAGE_SIZE;
        buf->st_mode = inode->i_mode;
        buf->st_ino = inode->i_ino;
        buf->st_nlink = inode->i_nlink;
        buf->st_uid = inode->i_uid;
        buf->st_gid = inode->i_gid;
        buf->st_size = inode->i_size;
        buf->st_atime = inode->i_atime;
        buf->st_mtime = inode->i_mtime;
        buf->st_ctime = inode->i_ctime;

        rtems_jffs2_do_unlock(sb);

        return 0;
}

static int rtems_jffs2_fill_dirent(struct dirent *de, off_t off, uint32_t ino, const char *name)
{
        int eno = 0;
        size_t len;

        memset(de, 0, sizeof(*de));

        de->d_off = off * sizeof(*de);
        de->d_reclen = sizeof(*de);
        de->d_ino = ino;

        len = strlen(name);
        de->d_namlen = len;

        if (len < sizeof(de->d_name) - 1) {
                memcpy(&de->d_name[0], name, len);
        } else {
                eno = EOVERFLOW;
        }

        return eno;
}

static ssize_t rtems_jffs2_dir_read(rtems_libio_t *iop, void *buf, size_t len)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_iop(iop);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct dirent *de = buf;
        off_t fd_off = 2;
        int eno = 0;
        struct jffs2_full_dirent *fd;
        off_t begin;
        off_t end;
        off_t off;

        rtems_jffs2_do_lock(inode->i_sb);

        fd = f->dents;
        begin = iop->offset;
        end = begin + len / sizeof(*de);
        off = begin;

        if (off == 0 && off < end) {
                eno = rtems_jffs2_fill_dirent(de, off, inode->i_ino, ".");
                assert(eno == 0);
                ++off;
                ++de;
        }

        if (off == 1 && off < end) {
                eno = rtems_jffs2_fill_dirent(de, off, inode->i_parent->i_ino, "..");
                assert(eno == 0);
                ++off;
                ++de;
        }

        while (eno == 0 && off < end && fd != NULL) {
                if (fd->ino != 0) {
                        if (off == fd_off) {
                                eno = rtems_jffs2_fill_dirent(de, off, fd->ino, fd->name);
                                ++off;
                                ++de;
                        }

                        ++fd_off;
                }

                fd = fd->next;
        }

        rtems_jffs2_do_unlock(inode->i_sb);

        if (eno == 0) {
                iop->offset = off;

                return (off - begin) * sizeof(*de);
        } else {
                return rtems_jffs2_eno_to_rv_and_errno(eno);
        }
}

static const rtems_filesystem_file_handlers_r rtems_jffs2_directory_handlers = {
        .open_h = rtems_filesystem_default_open,
        .close_h = rtems_filesystem_default_close,
        .read_h = rtems_jffs2_dir_read,
        .write_h = rtems_filesystem_default_write,
        .ioctl_h = rtems_filesystem_default_ioctl,
        .lseek_h = rtems_filesystem_default_lseek_directory,
        .fstat_h = rtems_jffs2_fstat,
        .ftruncate_h = rtems_filesystem_default_ftruncate_directory,
        .fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
        .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
        .fcntl_h = rtems_filesystem_default_fcntl,
        .kqfilter_h = rtems_filesystem_default_kqfilter,
        .poll_h = rtems_filesystem_default_poll,
        .readv_h = rtems_filesystem_default_readv,
        .writev_h = rtems_filesystem_default_writev
};

static ssize_t rtems_jffs2_file_read(rtems_libio_t *iop, void *buf, size_t len)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_iop(iop);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
        int err = 0;
        off_t pos;

        rtems_jffs2_do_lock(inode->i_sb);

        pos = iop->offset;

        if (pos >= inode->i_size) {
                len = 0;
        } else {
                uint32_t pos_32 = (uint32_t) pos;
                uint32_t max_available = inode->i_size - pos_32;

                if (len > max_available) {
                        len = max_available;
                }

                err = jffs2_read_inode_range(c, f, buf, pos_32, len);
        }

        if (err == 0) {
                iop->offset += len;
        }

        rtems_jffs2_do_unlock(inode->i_sb);

        if (err == 0) {
                return (ssize_t) len;
        } else {
                errno = -err;

                return -1;
        }
}

static ssize_t rtems_jffs2_file_write(rtems_libio_t *iop, const void *buf, size_t len)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_iop(iop);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
        struct jffs2_raw_inode ri;
        uint32_t writtenlen;
        off_t pos;
        int eno = 0;

        memset(&ri, 0, sizeof(ri));

        ri.ino = cpu_to_je32(f->inocache->ino);
        ri.mode = cpu_to_jemode(inode->i_mode);
        ri.uid = cpu_to_je16(inode->i_uid);
        ri.gid = cpu_to_je16(inode->i_gid);
        ri.atime = ri.ctime = ri.mtime = cpu_to_je32(get_seconds());

        rtems_jffs2_do_lock(inode->i_sb);

        if ((iop->flags & LIBIO_FLAGS_APPEND) == 0) {
                pos = iop->offset;
        } else {
                pos = inode->i_size;
        }

        if (pos > inode->i_size) {
                ri.version = cpu_to_je32(++f->highest_version);
                eno = -jffs2_extend_file(inode, &ri, pos);
        }

        if (eno == 0) {
                ri.isize = cpu_to_je32(inode->i_size);

                eno = -jffs2_write_inode_range(c, f, &ri, (void *) buf, pos, len, &writtenlen);
        }

        if (eno == 0) {
                pos += writtenlen;

                inode->i_mtime = inode->i_ctime = je32_to_cpu(ri.mtime);

                if (pos > inode->i_size) {
                        inode->i_size = pos;
                }

                iop->offset = pos;

                if (writtenlen != len) {
                        eno = ENOSPC;
                }
        }

        rtems_jffs2_do_unlock(inode->i_sb);

        if (eno == 0) {
                return writtenlen;
        } else {
                errno = eno;

                return -1;
        }
}

static int rtems_jffs2_file_ftruncate(rtems_libio_t *iop, off_t length)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_iop(iop);
        struct iattr iattr;
        int eno;

        iattr.ia_valid = ATTR_SIZE | ATTR_MTIME | ATTR_CTIME;
        iattr.ia_size = length;
        iattr.ia_mtime = get_seconds();
        iattr.ia_ctime = iattr.ia_mtime;

        rtems_jffs2_do_lock(inode->i_sb);

        eno = -jffs2_do_setattr(inode, &iattr);

        rtems_jffs2_do_unlock(inode->i_sb);

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static const rtems_filesystem_file_handlers_r rtems_jffs2_file_handlers = {
        .open_h = rtems_filesystem_default_open,
        .close_h = rtems_filesystem_default_close,
        .read_h = rtems_jffs2_file_read,
        .write_h = rtems_jffs2_file_write,
        .ioctl_h = rtems_filesystem_default_ioctl,
        .lseek_h = rtems_filesystem_default_lseek_file,
        .fstat_h = rtems_jffs2_fstat,
        .ftruncate_h = rtems_jffs2_file_ftruncate,
        .fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
        .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
        .fcntl_h = rtems_filesystem_default_fcntl,
        .kqfilter_h = rtems_filesystem_default_kqfilter,
        .poll_h = rtems_filesystem_default_poll,
        .readv_h = rtems_filesystem_default_readv,
        .writev_h = rtems_filesystem_default_writev
};

static const rtems_filesystem_file_handlers_r rtems_jffs2_link_handlers = {
        .open_h = rtems_filesystem_default_open,
        .close_h = rtems_filesystem_default_close,
        .read_h = rtems_filesystem_default_read,
        .write_h = rtems_filesystem_default_write,
        .ioctl_h = rtems_filesystem_default_ioctl,
        .lseek_h = rtems_filesystem_default_lseek,
        .fstat_h = rtems_jffs2_fstat,
        .ftruncate_h = rtems_filesystem_default_ftruncate,
        .fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
        .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
        .fcntl_h = rtems_filesystem_default_fcntl,
        .kqfilter_h = rtems_filesystem_default_kqfilter,
        .poll_h = rtems_filesystem_default_poll,
        .readv_h = rtems_filesystem_default_readv,
        .writev_h = rtems_filesystem_default_writev
};

static void rtems_jffs2_set_location(rtems_filesystem_location_info_t *loc, struct _inode *inode)
{
        loc->node_access = inode;

        switch (inode->i_mode & S_IFMT) {
                case S_IFREG:
                        loc->handlers = &rtems_jffs2_file_handlers;
                        break;
                case S_IFDIR:
                        loc->handlers = &rtems_jffs2_directory_handlers;
                        break;
                case S_IFLNK:
                        loc->handlers = &rtems_jffs2_link_handlers;
                        break;
                default:
                        loc->handlers = &rtems_filesystem_null_handlers;
                        break;
        };
}

static bool rtems_jffs2_eval_is_directory(
        rtems_filesystem_eval_path_context_t *ctx,
        void *arg
)
{
        rtems_filesystem_location_info_t *currentloc =
                rtems_filesystem_eval_path_get_currentloc(ctx);
        struct _inode *inode = rtems_jffs2_get_inode_by_location(currentloc);

        return S_ISDIR(inode->i_mode);
}

static rtems_filesystem_eval_path_generic_status rtems_jffs2_eval_token(
        rtems_filesystem_eval_path_context_t *ctx,
        void *arg,
        const char *token,
        size_t tokenlen
)
{
        rtems_filesystem_eval_path_generic_status status =
                RTEMS_FILESYSTEM_EVAL_PATH_GENERIC_DONE;
        rtems_filesystem_location_info_t *currentloc =
                rtems_filesystem_eval_path_get_currentloc(ctx);
        struct _inode *dir_i = rtems_jffs2_get_inode_by_location(currentloc);
        bool access_ok = rtems_filesystem_eval_path_check_access(
                ctx,
                RTEMS_FS_PERMS_EXEC,
                dir_i->i_mode,
                dir_i->i_uid,
                dir_i->i_gid
        );

        if (access_ok) {
                struct _inode *entry_i;

                if (rtems_filesystem_is_current_directory(token, tokenlen)) {
                        entry_i = dir_i;
                        ++entry_i->i_count;
                } else if (rtems_filesystem_is_parent_directory(token, tokenlen)) {
                        entry_i = dir_i->i_parent;
                        ++entry_i->i_count;
                } else {
                        entry_i = jffs2_lookup(dir_i, token, (int) tokenlen);
                }

                if (IS_ERR(entry_i)) {
                        rtems_filesystem_eval_path_error(ctx, PTR_ERR(entry_i));
                } else if (entry_i != NULL) {
                        bool terminal = !rtems_filesystem_eval_path_has_path(ctx);
                        int eval_flags = rtems_filesystem_eval_path_get_flags(ctx);
                        bool follow_sym_link = (eval_flags & RTEMS_FS_FOLLOW_SYM_LINK) != 0;

                        rtems_filesystem_eval_path_clear_token(ctx);

                        if (S_ISLNK(entry_i->i_mode) && (follow_sym_link || !terminal)) {
                                struct jffs2_inode_info *f = JFFS2_INODE_INFO(entry_i);
                                const char *target = f->target;

                                rtems_filesystem_eval_path_recursive(ctx, target, strlen(target));

                                jffs2_iput(entry_i);
                        } else {
                                if (S_ISDIR(entry_i->i_mode) && entry_i->i_parent == NULL) {
                                        entry_i->i_parent = dir_i;
                                        ++dir_i->i_count;
                                }

                                jffs2_iput(dir_i);
                                rtems_jffs2_set_location(currentloc, entry_i);

                                if (rtems_filesystem_eval_path_has_path(ctx)) {
                                        status = RTEMS_FILESYSTEM_EVAL_PATH_GENERIC_CONTINUE;
                                }
                        }
                } else {
                        status = RTEMS_FILESYSTEM_EVAL_PATH_GENERIC_NO_ENTRY;
                }
        }

        return status;
}

static const rtems_filesystem_eval_path_generic_config rtems_jffs2_eval_config = {
        .is_directory = rtems_jffs2_eval_is_directory,
        .eval_token = rtems_jffs2_eval_token
};

static void rtems_jffs2_lock(const rtems_filesystem_mount_table_entry_t *mt_entry)
{
        const rtems_jffs2_fs_info *fs_info = mt_entry->fs_info;
        const struct super_block *sb = &fs_info->sb;

        rtems_jffs2_do_lock(sb);
}

static void rtems_jffs2_unlock(const rtems_filesystem_mount_table_entry_t *mt_entry)
{
        const rtems_jffs2_fs_info *fs_info = mt_entry->fs_info;
        const struct super_block *sb = &fs_info->sb;

        rtems_jffs2_do_unlock(sb);
}

static void rtems_jffs2_eval_path(rtems_filesystem_eval_path_context_t *ctx)
{
        rtems_filesystem_eval_path_generic(ctx, NULL, &rtems_jffs2_eval_config);
}

static int rtems_jffs2_link(
        const rtems_filesystem_location_info_t *parentloc,
        const rtems_filesystem_location_info_t *targetloc,
        const char *name,
        size_t namelen
)
{
        struct _inode *old_d_inode = rtems_jffs2_get_inode_by_location(targetloc);
        struct _inode *dir_i = rtems_jffs2_get_inode_by_location(parentloc);
        int eno;

        eno = -jffs2_link(old_d_inode, dir_i, name, namelen);

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static bool rtems_jffs2_are_nodes_equal(
        const rtems_filesystem_location_info_t *a,
        const rtems_filesystem_location_info_t *b
)
{
        struct _inode *inode_a = rtems_jffs2_get_inode_by_location(a);
        struct _inode *inode_b = rtems_jffs2_get_inode_by_location(b);

        return inode_a->i_ino == inode_b->i_ino;
}

static int rtems_jffs2_mknod(
        const rtems_filesystem_location_info_t *parentloc,
        const char *name,
        size_t namelen,
        mode_t mode,
        dev_t dev
)
{
        struct _inode *dir_i = rtems_jffs2_get_inode_by_location(parentloc);
        int eno;

        switch (mode & S_IFMT) {
                case S_IFDIR:
                        eno = -jffs2_mknod(dir_i, name, namelen, mode, NULL, 0);
                        break;
                case S_IFREG:
                        eno = -jffs2_create(dir_i, name, namelen, mode);
                        break;
                default:
                        eno = EINVAL;
                        break;
        }

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static int rtems_jffs2_cache_fd_name(struct _inode *inode, char **name, size_t *namelen)
{
        struct super_block *sb = inode->i_sb;
        char *fd_name = inode->i_fd->name;
        size_t fd_namelen = strlen(fd_name);
        int eno = 0;

        if (fd_namelen <= sizeof(sb->s_name_buf)) {
                *namelen = fd_namelen;
                *name = memcpy(&sb->s_name_buf[0], fd_name, fd_namelen);
        } else {
                eno = ENOMEM;
        }

        return eno;
}

static int rtems_jffs2_rmnod(
        const rtems_filesystem_location_info_t *parentloc,
        const rtems_filesystem_location_info_t *loc
)
{
        struct _inode *dir_i = rtems_jffs2_get_inode_by_location(parentloc);
        struct _inode *entry_i = rtems_jffs2_get_inode_by_location(loc);
        char *name;
        size_t namelen;
        int eno = rtems_jffs2_cache_fd_name(entry_i, &name, &namelen);

        if (eno == 0) {
                switch (dir_i->i_mode & S_IFMT) {
                        case S_IFDIR:
                                eno = -jffs2_rmdir(dir_i, entry_i, name, namelen);
                                break;
                        case S_IFREG:
                                eno = -jffs2_unlink(dir_i, entry_i, name, namelen);
                                break;
                        default:
                                eno = EINVAL;
                                break;
                }
        }

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static int rtems_jffs2_fchmod(
        const rtems_filesystem_location_info_t *loc,
        mode_t mode
)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);
        struct iattr iattr;
        int eno;

        iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
        iattr.ia_mode = mode;
        iattr.ia_ctime = get_seconds();

        eno = -jffs2_do_setattr(inode, &iattr);

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static int rtems_jffs2_chown(
        const rtems_filesystem_location_info_t *loc,
        uid_t owner,
        gid_t group
)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);
        struct iattr iattr;
        int eno;

        iattr.ia_valid = ATTR_UID | ATTR_GID | ATTR_CTIME;
        iattr.ia_uid = owner;
        iattr.ia_gid = group;
        iattr.ia_ctime = get_seconds();

        eno = -jffs2_do_setattr(inode, &iattr);

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static int rtems_jffs2_clonenode(rtems_filesystem_location_info_t *loc)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);

        ++inode->i_count;

        return 0;
}

static void rtems_jffs2_freenode(const rtems_filesystem_location_info_t *loc)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);

        jffs2_iput(inode);
}

static void rtems_jffs2_fsunmount(rtems_filesystem_mount_table_entry_t *mt_entry)
{
        rtems_jffs2_fs_info *fs_info = mt_entry->fs_info;
        struct _inode *root_i = mt_entry->mt_fs_root->location.node_access;

        icache_evict(root_i, NULL);
        assert(root_i->i_cache_next == NULL);
        assert(root_i->i_count == 1);
        jffs2_iput(root_i);

        rtems_jffs2_free_directory_entries(root_i);
        free(root_i);

        rtems_jffs2_free_fs_info(fs_info, true);
}

static int rtems_jffs2_rename(
        const rtems_filesystem_location_info_t *oldparentloc,
        const rtems_filesystem_location_info_t *oldloc,
        const rtems_filesystem_location_info_t *newparentloc,
        const char *name,
        size_t namelen
)
{
        struct _inode *old_dir_i = rtems_jffs2_get_inode_by_location(oldparentloc);
        struct _inode *new_dir_i = rtems_jffs2_get_inode_by_location(newparentloc);
        struct _inode *d_inode = rtems_jffs2_get_inode_by_location(oldloc);
        char *oldname;
        size_t oldnamelen;
        int eno = rtems_jffs2_cache_fd_name(d_inode, &oldname, &oldnamelen);

        if (eno == 0) {
                eno = -jffs2_rename(old_dir_i, d_inode, oldname, oldnamelen, new_dir_i, name, namelen);
        }

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static int rtems_jffs2_statvfs(
        const rtems_filesystem_location_info_t *__restrict loc,
        struct statvfs *__restrict buf
)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);
        struct super_block *sb = inode->i_sb;
        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
        unsigned long avail;

        spin_lock(&c->erase_completion_lock);
        avail = c->dirty_size + c->free_size;
        if (avail > c->sector_size * c->resv_blocks_write) {
                avail -= c->sector_size * c->resv_blocks_write;
        } else {
                avail = 0;
        }
        spin_unlock(&c->erase_completion_lock);

        buf->f_bavail = avail >> PAGE_SHIFT;
        buf->f_blocks = c->flash_size >> PAGE_SHIFT;
        buf->f_bsize = 1UL << PAGE_SHIFT;
        buf->f_fsid = JFFS2_SUPER_MAGIC;
        buf->f_namemax = JFFS2_MAX_NAME_LEN;

        buf->f_bfree = buf->f_bavail;
        buf->f_frsize = buf->f_bsize;

        return 0;
}

static int rtems_jffs2_utime(
        const rtems_filesystem_location_info_t *loc,
        time_t actime,
        time_t modtime
)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);
        struct iattr iattr;
        int eno;

        iattr.ia_valid = ATTR_ATIME | ATTR_MTIME | ATTR_CTIME;
        iattr.ia_atime = actime;
        iattr.ia_mtime = modtime;
        iattr.ia_ctime = get_seconds();

        eno = -jffs2_do_setattr(inode, &iattr);

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static int rtems_jffs2_symlink(
        const rtems_filesystem_location_info_t *parentloc,
        const char *name,
        size_t namelen,
        const char *target
)
{
        struct _inode *dir_i = rtems_jffs2_get_inode_by_location(parentloc);
        int eno;

        eno = -jffs2_mknod(dir_i, name, namelen, S_IFLNK | S_IRWXUGO, target, strlen(target));

        return rtems_jffs2_eno_to_rv_and_errno(eno);
}

static ssize_t rtems_jffs2_readlink(
        const rtems_filesystem_location_info_t *loc,
        char *buf,
        size_t bufsize
)
{
        struct _inode *inode = rtems_jffs2_get_inode_by_location(loc);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
        const char *target = f->target;
        ssize_t i;

        for (i = 0; i < (ssize_t) bufsize && target[i] != '\0'; ++i) {
                buf[i] = target[i];
        }

        return i;
}

static const rtems_filesystem_operations_table rtems_jffs2_ops = {
        .lock_h = rtems_jffs2_lock,
        .unlock_h = rtems_jffs2_unlock,
        .eval_path_h = rtems_jffs2_eval_path,
        .link_h = rtems_jffs2_link,
        .are_nodes_equal_h = rtems_jffs2_are_nodes_equal,
        .mknod_h = rtems_jffs2_mknod,
        .rmnod_h = rtems_jffs2_rmnod,
        .fchmod_h = rtems_jffs2_fchmod,
        .chown_h = rtems_jffs2_chown,
        .clonenod_h = rtems_jffs2_clonenode,
        .freenod_h = rtems_jffs2_freenode,
        .mount_h = rtems_filesystem_default_mount,
        .unmount_h = rtems_filesystem_default_unmount,
        .fsunmount_me_h = rtems_jffs2_fsunmount,
        .utime_h = rtems_jffs2_utime,
        .symlink_h = rtems_jffs2_symlink,
        .readlink_h = rtems_jffs2_readlink,
        .rename_h = rtems_jffs2_rename,
        .statvfs_h = rtems_jffs2_statvfs
};

static int calculate_inocache_hashsize(uint32_t flash_size)
{
        /*
         * Pick a inocache hash size based on the size of the medium.
         * Count how many megabytes we're dealing with, apply a hashsize twice
         * that size, but rounding down to the usual big powers of 2. And keep
         * to sensible bounds.
         */

        int size_mb = flash_size / 1024 / 1024;
        int hashsize = (size_mb * 2) & ~0x3f;

        if (hashsize < INOCACHE_HASHSIZE_MIN)
                return INOCACHE_HASHSIZE_MIN;
        if (hashsize > INOCACHE_HASHSIZE_MAX)
                return INOCACHE_HASHSIZE_MAX;

        return hashsize;
}

int rtems_jffs2_initialize(
        rtems_filesystem_mount_table_entry_t *mt_entry,
        const void *data
)
{
        const rtems_jffs2_mount_data *jffs2_mount_data = data;
        rtems_jffs2_flash_control *fc = jffs2_mount_data->flash_control;
        int inocache_hashsize = calculate_inocache_hashsize(fc->flash_size);
        rtems_jffs2_fs_info *fs_info = calloc(
                1,
                sizeof(*fs_info) + (size_t) inocache_hashsize * sizeof(fs_info->inode_cache[0])
        );
        bool do_mount_fs_was_successful = false;
        struct super_block *sb;
        struct jffs2_sb_info *c;
        int err;

        if (fs_info != NULL) {
                err = 0;
        } else {
                err = -ENOMEM;
        }

        sb = &fs_info->sb;
        c = JFFS2_SB_INFO(sb);

        if (err == 0) {
                uint32_t blocks = fc->flash_size / fc->block_size;

                if ((fc->block_size * blocks) != fc->flash_size) {
                        fc->flash_size = fc->block_size * blocks;
                        pr_info("Flash size not aligned to erasesize, reducing to %dKiB\n",
                                fc->flash_size / 1024);
                }

                if (fc->flash_size < 5*fc->block_size) {
                        pr_err("Too few erase blocks (%d)\n",
                               fc->flash_size / fc->block_size);
                        err = -EINVAL;
                }
        }

        if (err == 0) {
                rtems_status_code sc = rtems_semaphore_create(
                        rtems_build_name('J', 'F', 'F', 'S'),
                        1,
                        RTEMS_PRIORITY | RTEMS_INHERIT_PRIORITY | RTEMS_BINARY_SEMAPHORE,
                        0,
                        &sb->s_mutex
                );

                err = sc == RTEMS_SUCCESSFUL ? 0 : -ENOMEM;
        }

        if (err == 0) {
                sb->s_is_readonly = !mt_entry->writeable;
                sb->s_flash_control = fc;
                sb->s_compressor_control = jffs2_mount_data->compressor_control;

                c->inocache_hashsize = inocache_hashsize;
                c->inocache_list = &fs_info->inode_cache[0];
                c->sector_size = fc->block_size;
                c->flash_size = fc->flash_size;
                c->cleanmarker_size = sizeof(struct jffs2_unknown_node);

                err = jffs2_do_mount_fs(c);
        }

        if (err == 0) {
                do_mount_fs_was_successful = true;

                sb->s_root = jffs2_iget(sb, 1);
                if (IS_ERR(sb->s_root)) {
                        err = PTR_ERR(sb->s_root);
                }
        }

        if (err == 0) {
                sb->s_root->i_parent = sb->s_root;

                if (!jffs2_is_readonly(c)) {
                        jffs2_erase_pending_blocks(c, 0);
                }

                mt_entry->fs_info = fs_info;
                mt_entry->ops = &rtems_jffs2_ops;
                mt_entry->mt_fs_root->location.node_access = sb->s_root;
                mt_entry->mt_fs_root->location.handlers = &rtems_jffs2_directory_handlers;

                return 0;
        } else {
                if (fs_info != NULL) {
                        rtems_jffs2_free_fs_info(fs_info, do_mount_fs_was_successful);
                } else {
                        rtems_jffs2_flash_control_destroy(fc);
                        rtems_jffs2_compressor_control_destroy(jffs2_mount_data->compressor_control);
                }

                errno = -err;

                return -1;
        }
}

//==========================================================================
// 
// Called by JFFS2
// ===============
// 
//
//==========================================================================

unsigned char *jffs2_gc_fetch_page(struct jffs2_sb_info *c, 
                                   struct jffs2_inode_info *f, 
                                   unsigned long offset,
                                   unsigned long *priv)
{
        int ret;
        struct super_block *sb = OFNI_BS_2SFFJ(c);
        unsigned char *gc_buffer = &sb->s_gc_buffer[0];

        ret = jffs2_read_inode_range(c, f, gc_buffer, 
                                     offset & ~(PAGE_CACHE_SIZE-1), PAGE_CACHE_SIZE);
        if (ret)
                return ERR_PTR(ret);

        return gc_buffer;
}

void jffs2_gc_release_page(struct jffs2_sb_info *c,
                           unsigned char *ptr,
                           unsigned long *priv)
{
        /* Do nothing */
}

static struct _inode *new_inode(struct super_block *sb)
{

        // Only called in write.c jffs2_new_inode
        // Always adds itself to inode cache

        struct _inode *inode;
        struct _inode *cached_inode;

        inode = malloc(sizeof (struct _inode));
        if (inode == NULL)
                return 0;

        D2(printf
           ("malloc new_inode %x ####################################\n",
            inode));

        memset(inode, 0, sizeof (struct _inode));
        inode->i_sb = sb;
        inode->i_ino = 1;
        inode->i_count = 1;
        inode->i_nlink = 1;     // Let JFFS2 manage the link count
        inode->i_size = 0;

        inode->i_cache_next = NULL;     // Newest inode, about to be cached

        // Add to the icache
        for (cached_inode = sb->s_root; cached_inode != NULL;
             cached_inode = cached_inode->i_cache_next) {
                if (cached_inode->i_cache_next == NULL) {
                        cached_inode->i_cache_next = inode;     // Current last in cache points to newcomer
                        inode->i_cache_prev = cached_inode;     // Newcomer points back to last
                        break;
                }
        }
        return inode;
}

static struct _inode *ilookup(struct super_block *sb, cyg_uint32 ino)
{
        struct _inode *inode = NULL;

        D2(printf("ilookup\n"));
        // Check for this inode in the cache
        for (inode = sb->s_root; inode != NULL; inode = inode->i_cache_next) {
                if (inode->i_ino == ino) {
                        inode->i_count++;
                        break;
                }
        }
        return inode;
}

struct _inode *jffs2_iget(struct super_block *sb, cyg_uint32 ino)
{
        // Called in super.c jffs2_read_super, dir.c jffs2_lookup,
        // and gc.c jffs2_garbage_collect_pass

        // Must first check for cached inode 
        // If this fails let new_inode create one

        struct _inode *inode;
        int err;

        D2(printf("jffs2_iget\n"));

        inode = ilookup(sb, ino);
        if (inode)
                return inode;

        // Not cached, so malloc it
        inode = new_inode(sb);
        if (inode == NULL)
                return ERR_PTR(-ENOMEM);

        inode->i_ino = ino;

        err = jffs2_read_inode(inode);
        if (err) {
                printk("jffs2_read_inode() failed\n");
                inode->i_nlink = 0; // free _this_ bad inode right now
                jffs2_iput(inode);
                inode = NULL;
                return ERR_PTR(err);
        }
        return inode;
}

// -------------------------------------------------------------------------
// Decrement the reference count on an inode. If this makes the ref count
// zero, then this inode can be freed.

void jffs2_iput(struct _inode *i)
{
        // Called in jffs2_find 
        // (and jffs2_open and jffs2_ops_mkdir?)
        // super.c jffs2_read_super,
        // and gc.c jffs2_garbage_collect_pass
 recurse:
        assert(i != NULL);

        i->i_count--;

        if (i->i_count < 0)
                BUG();

        if (i->i_count)
                return;
        
        if (!i->i_nlink) {
                struct _inode *parent;

                // Remove from the icache linked list and free immediately
                if (i->i_cache_prev)
                        i->i_cache_prev->i_cache_next = i->i_cache_next;
                if (i->i_cache_next)
                        i->i_cache_next->i_cache_prev = i->i_cache_prev;

                parent = i->i_parent;
                jffs2_clear_inode(i);
                memset(i, 0x5a, sizeof(*i));
                free(i);

                if (parent && parent != i) {
                        i = parent;
                        goto recurse;
                }

        } else {
                // Evict some _other_ inode with i_count zero, leaving
                // this latest one in the cache for a while 
                icache_evict(i->i_sb->s_root, i);
        }
}


// -------------------------------------------------------------------------
// EOF jffs2.c


static inline void jffs2_init_inode_info(struct jffs2_inode_info *f)
{
        memset(f, 0, sizeof(*f));
}

static void jffs2_clear_inode (struct _inode *inode)
{
        /* We can forget about this inode for now - drop all
         *  the nodelists associated with it, etc.
         */
        struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
        struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);

        D1(printk(KERN_DEBUG "jffs2_clear_inode(): ino #%lu mode %o\n", inode->i_ino, inode->i_mode));

        jffs2_do_clear_inode(c, f);
}


/* jffs2_new_inode: allocate a new inode and inocache, add it to the hash,
   fill in the raw_inode while you're at it. */
struct _inode *jffs2_new_inode (struct _inode *dir_i, int mode, struct jffs2_raw_inode *ri)
{
        struct _inode *inode;
        struct super_block *sb = dir_i->i_sb;
        struct jffs2_sb_info *c;
        struct jffs2_inode_info *f;
        int ret;

        D1(printk(KERN_DEBUG "jffs2_new_inode(): dir_i %ld, mode 0x%x\n", dir_i->i_ino, mode));

        c = JFFS2_SB_INFO(sb);
        
        inode = new_inode(sb);
        
        if (!inode)
                return ERR_PTR(-ENOMEM);

        f = JFFS2_INODE_INFO(inode);
        jffs2_init_inode_info(f);

        memset(ri, 0, sizeof(*ri));
        /* Set OS-specific defaults for new inodes */
        ri->uid = cpu_to_je16(geteuid());
        ri->gid = cpu_to_je16(getegid());
        ri->mode =  cpu_to_jemode(mode);
        ret = jffs2_do_new_inode (c, f, mode, ri);
        if (ret) {
                // forceful evict: f->sem is locked already, and the
                // inode is bad.
                if (inode->i_cache_prev)
                       inode->i_cache_prev->i_cache_next = inode->i_cache_next;
                if (inode->i_cache_next)
                       inode->i_cache_next->i_cache_prev = inode->i_cache_prev; 
                mutex_unlock(&(f->sem));
                jffs2_clear_inode(inode);
                memset(inode, 0x6a, sizeof(*inode));
                free(inode);
                return ERR_PTR(ret);
        }
        inode->i_nlink = 1;
        inode->i_ino = je32_to_cpu(ri->ino);
        inode->i_mode = jemode_to_cpu(ri->mode);
        inode->i_gid = je16_to_cpu(ri->gid);
        inode->i_uid = je16_to_cpu(ri->uid);
        inode->i_atime = inode->i_ctime = inode->i_mtime = get_seconds();
        ri->atime = ri->mtime = ri->ctime = cpu_to_je32(inode->i_mtime);

        inode->i_size = 0;

        return inode;
}


static int jffs2_read_inode (struct _inode *inode)
{
        struct jffs2_inode_info *f;
        struct jffs2_sb_info *c;
        struct jffs2_raw_inode latest_node;
        int ret;

        D1(printk(KERN_DEBUG "jffs2_read_inode(): inode->i_ino == %lu\n", inode->i_ino));

        f = JFFS2_INODE_INFO(inode);
        c = JFFS2_SB_INFO(inode->i_sb);

        jffs2_init_inode_info(f);
        
        ret = jffs2_do_read_inode(c, f, inode->i_ino, &latest_node);

        if (ret) {
                mutex_unlock(&f->sem);
                return ret;
        }
        inode->i_mode = jemode_to_cpu(latest_node.mode);
        inode->i_uid = je16_to_cpu(latest_node.uid);
        inode->i_gid = je16_to_cpu(latest_node.gid);
        inode->i_size = je32_to_cpu(latest_node.isize);
        inode->i_atime = je32_to_cpu(latest_node.atime);
        inode->i_mtime = je32_to_cpu(latest_node.mtime);
        inode->i_ctime = je32_to_cpu(latest_node.ctime);

        inode->i_nlink = f->inocache->pino_nlink;
        mutex_unlock(&f->sem);

        D1(printk(KERN_DEBUG "jffs2_read_inode() returning\n"));
        return 0;
}


void jffs2_gc_release_inode(struct jffs2_sb_info *c,
                                   struct jffs2_inode_info *f)
{
        jffs2_iput(OFNI_EDONI_2SFFJ(f));
}

struct jffs2_inode_info *jffs2_gc_fetch_inode(struct jffs2_sb_info *c,
                                              int inum, int unlinked)
{
        struct _inode *inode;
        struct jffs2_inode_cache *ic;

        if (unlinked) {
                /* The inode has zero nlink but its nodes weren't yet marked
                   obsolete. This has to be because we're still waiting for
                   the final (close() and) iput() to happen.

                   There's a possibility that the final iput() could have
                   happened while we were contemplating. In order to ensure
                   that we don't cause a new read_inode() (which would fail)
                   for the inode in question, we use ilookup() in this case
                   instead of iget().

                   The nlink can't _become_ zero at this point because we're
                   holding the alloc_sem, and jffs2_do_unlink() would also
                   need that while decrementing nlink on any inode.
                */
                inode = ilookup(OFNI_BS_2SFFJ(c), inum);
                if (!inode) {
                        jffs2_dbg(1, "ilookup() failed for ino #%u; inode is probably deleted.\n",
                                  inum);

                        spin_lock(&c->inocache_lock);
                        ic = jffs2_get_ino_cache(c, inum);
                        if (!ic) {
                                jffs2_dbg(1, "Inode cache for ino #%u is gone\n",
                                          inum);
                                spin_unlock(&c->inocache_lock);
                                return NULL;
                        }
                        if (ic->state != INO_STATE_CHECKEDABSENT) {
                                /* Wait for progress. Don't just loop */
                                jffs2_dbg(1, "Waiting for ino #%u in state %d\n",
                                          ic->ino, ic->state);
                                sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
                        } else {
                                spin_unlock(&c->inocache_lock);
                        }

                        return NULL;
                }
        } else {
                /* Inode has links to it still; they're not going away because
                   jffs2_do_unlink() would need the alloc_sem and we have it.
                   Just iget() it, and if read_inode() is necessary that's OK.
                */
                inode = jffs2_iget(OFNI_BS_2SFFJ(c), inum);
                if (IS_ERR(inode))
                        return ERR_CAST(inode);
        }

        return JFFS2_INODE_INFO(inode);
}