fuse_lowlevel.c

Linux下fuse用户文件系统的的源代码

        fuse_reply_err(req, ENOSYS);
}

static void do_readlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    (void) inarg;

    if (req->f->op.readlink)
        req->f->op.readlink(req, nodeid);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_mknod(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_mknod_in *arg = (struct fuse_mknod_in *) inarg;

    if (req->f->op.mknod)
        req->f->op.mknod(req, nodeid, PARAM(arg), arg->mode, arg->rdev);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_mkdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_mkdir_in *arg = (struct fuse_mkdir_in *) inarg;

    if (req->f->op.mkdir)
        req->f->op.mkdir(req, nodeid, PARAM(arg), arg->mode);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_unlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    char *name = (char *) inarg;

    if (req->f->op.unlink)
        req->f->op.unlink(req, nodeid, name);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_rmdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    char *name = (char *) inarg;

    if (req->f->op.rmdir)
        req->f->op.rmdir(req, nodeid, name);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_symlink(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    char *name = (char *) inarg;
    char *linkname = ((char *) inarg) + strlen((char *) inarg) + 1;

    if (req->f->op.symlink)
        req->f->op.symlink(req, linkname, nodeid, name);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_rename(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_rename_in *arg = (struct fuse_rename_in *) inarg;
    char *oldname = PARAM(arg);
    char *newname = oldname + strlen(oldname) + 1;

    if (req->f->op.rename)
        req->f->op.rename(req, nodeid, oldname, arg->newdir, newname);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_link(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_link_in *arg = (struct fuse_link_in *) inarg;

    if (req->f->op.link)
        req->f->op.link(req, arg->oldnodeid, nodeid, PARAM(arg));
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_create(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_open_in *arg = (struct fuse_open_in *) inarg;

    if (req->f->op.create) {
        struct fuse_file_info fi;

        memset(&fi, 0, sizeof(fi));
        fi.flags = arg->flags;

        req->f->op.create(req, nodeid, PARAM(arg), arg->mode, &fi);
    } else
        fuse_reply_err(req, ENOSYS);
}

static void do_open(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_open_in *arg = (struct fuse_open_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;

    if (req->f->op.open)
        req->f->op.open(req, nodeid, &fi);
    else
        fuse_reply_open(req, &fi);
}

static void do_read(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_read_in *arg = (struct fuse_read_in *) inarg;

    if (req->f->op.read) {
        struct fuse_file_info fi;

        memset(&fi, 0, sizeof(fi));
        fi.fh = arg->fh;
        fi.fh_old = fi.fh;
        req->f->op.read(req, nodeid, arg->size, arg->offset, &fi);
    } else
        fuse_reply_err(req, ENOSYS);
}

static void do_write(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_write_in *arg = (struct fuse_write_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;
    fi.writepage = arg->write_flags & 1;

    if (req->f->op.write)
        req->f->op.write(req, nodeid, PARAM(arg), arg->size, arg->offset, &fi);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_flush(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_flush_in *arg = (struct fuse_flush_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;
    fi.flush = 1;
    if (req->f->conn.proto_minor >= 7)
        fi.lock_owner = arg->lock_owner;

    if (req->f->op.flush)
        req->f->op.flush(req, nodeid, &fi);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_release(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_release_in *arg = (struct fuse_release_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;
    if (req->f->conn.proto_minor >= 8) {
        fi.flush = (arg->release_flags & FUSE_RELEASE_FLUSH) ? 1 : 0;
        fi.lock_owner = arg->lock_owner;
    }

    if (req->f->op.release)
        req->f->op.release(req, nodeid, &fi);
    else
        fuse_reply_err(req, 0);
}

static void do_fsync(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_fsync_in *arg = (struct fuse_fsync_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;

    if (req->f->op.fsync)
        req->f->op.fsync(req, nodeid, arg->fsync_flags & 1, &fi);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_opendir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_open_in *arg = (struct fuse_open_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;

    if (req->f->op.opendir)
        req->f->op.opendir(req, nodeid, &fi);
    else
        fuse_reply_open(req, &fi);
}

static void do_readdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_read_in *arg = (struct fuse_read_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;

    if (req->f->op.readdir)
        req->f->op.readdir(req, nodeid, arg->size, arg->offset, &fi);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_releasedir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_release_in *arg = (struct fuse_release_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.flags = arg->flags;
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;

    if (req->f->op.releasedir)
        req->f->op.releasedir(req, nodeid, &fi);
    else
        fuse_reply_err(req, 0);
}

static void do_fsyncdir(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_fsync_in *arg = (struct fuse_fsync_in *) inarg;
    struct fuse_file_info fi;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.fh_old = fi.fh;

    if (req->f->op.fsyncdir)
        req->f->op.fsyncdir(req, nodeid, arg->fsync_flags & 1, &fi);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_statfs(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    (void) nodeid;
    (void) inarg;

    if (req->f->op.statfs)
        req->f->op.statfs(req, nodeid);
    else {
        struct statvfs buf = {
            .f_namemax = 255,
            .f_bsize = 512,
        };
        fuse_reply_statfs(req, &buf);
    }
}

static void do_setxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_setxattr_in *arg = (struct fuse_setxattr_in *) inarg;
    char *name = PARAM(arg);
    char *value = name + strlen(name) + 1;

    if (req->f->op.setxattr)
        req->f->op.setxattr(req, nodeid, name, value, arg->size, arg->flags);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_getxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_getxattr_in *arg = (struct fuse_getxattr_in *) inarg;

    if (req->f->op.getxattr)
        req->f->op.getxattr(req, nodeid, PARAM(arg), arg->size);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_listxattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_getxattr_in *arg = (struct fuse_getxattr_in *) inarg;

    if (req->f->op.listxattr)
        req->f->op.listxattr(req, nodeid, arg->size);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_removexattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    char *name = (char *) inarg;

    if (req->f->op.removexattr)
        req->f->op.removexattr(req, nodeid, name);
    else
        fuse_reply_err(req, ENOSYS);
}

static void convert_fuse_file_lock(struct fuse_file_lock *fl,
                                   struct flock *flock)
{
    memset(flock, 0, sizeof(struct flock));
    flock->l_type = fl->type;
    flock->l_whence = SEEK_SET;
    flock->l_start = fl->start;
    if (fl->end == OFFSET_MAX)
        flock->l_len = 0;
    else
        flock->l_len = fl->end - fl->start + 1;
    flock->l_pid = fl->pid;
}

static void do_getlk(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_lk_in *arg = (struct fuse_lk_in *) inarg;
    struct fuse_file_info fi;
    struct flock flock;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.lock_owner = arg->owner;

    convert_fuse_file_lock(&arg->lk, &flock);
    if (req->f->op.getlk)
        req->f->op.getlk(req, nodeid, &fi, &flock);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_setlk_common(fuse_req_t req, fuse_ino_t nodeid,
                            const void *inarg, int sleep)
{
    struct fuse_lk_in *arg = (struct fuse_lk_in *) inarg;
    struct fuse_file_info fi;
    struct flock flock;

    memset(&fi, 0, sizeof(fi));
    fi.fh = arg->fh;
    fi.lock_owner = arg->owner;

    convert_fuse_file_lock(&arg->lk, &flock);
    if (req->f->op.setlk)
        req->f->op.setlk(req, nodeid, &fi, &flock, sleep);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_setlk(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    do_setlk_common(req, nodeid, inarg, 0);
}

static void do_setlkw(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    do_setlk_common(req, nodeid, inarg, 1);
}

static int find_interrupted(struct fuse_ll *f, struct fuse_req *req)
{
    struct fuse_req *curr;

    for (curr = f->list.next; curr != &f->list; curr = curr->next) {
        if (curr->unique == req->u.i.unique) {
            curr->ctr++;
            pthread_mutex_unlock(&f->lock);

            /* Ugh, ugly locking */
            pthread_mutex_lock(&curr->lock);
            pthread_mutex_lock(&f->lock);
            curr->interrupted = 1;
            pthread_mutex_unlock(&f->lock);
            if (curr->u.ni.func)
                curr->u.ni.func(curr, curr->u.ni.data);
            pthread_mutex_unlock(&curr->lock);

            pthread_mutex_lock(&f->lock);
            curr->ctr--;
            if (!curr->ctr)
                destroy_req(curr);

            return 1;
        }
    }
    for (curr = f->interrupts.next; curr != &f->interrupts;
         curr = curr->next) {
        if (curr->u.i.unique == req->u.i.unique)
            return 1;
    }
    return 0;
}

static void do_interrupt(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_interrupt_in *arg = (struct fuse_interrupt_in *) inarg;
    struct fuse_ll *f = req->f;

    (void) nodeid;
    if (f->debug) {
        printf("INTERRUPT: %llu\n", (unsigned long long) arg->unique);
        fflush(stdout);
    }

    req->u.i.unique = arg->unique;

    pthread_mutex_lock(&f->lock);
    if (find_interrupted(f, req))
        destroy_req(req);
    else
        list_add_req(req, &f->interrupts);
    pthread_mutex_unlock(&f->lock);
}

static struct fuse_req *check_interrupt(struct fuse_ll *f, struct fuse_req *req)
{
    struct fuse_req *curr;

    for (curr = f->interrupts.next; curr != &f->interrupts; curr = curr->next) {
        if (curr->u.i.unique == req->unique) {
            req->interrupted = 1;
            list_del_req(curr);
            free(curr);
            return NULL;
        }
    }
    curr = f->interrupts.next;
    if (curr != &f->interrupts) {
        list_del_req(curr);
        list_init_req(curr);
        return curr;
    } else
        return NULL;
}

static void do_bmap(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_bmap_in *arg = (struct fuse_bmap_in *) inarg;

    if (req->f->op.bmap)
        req->f->op.bmap(req, nodeid, arg->blocksize, arg->block);
    else
        fuse_reply_err(req, ENOSYS);
}

static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
{
    struct fuse_init_in *arg = (struct fuse_init_in *) inarg;
    struct fuse_init_out outarg;
    struct fuse_ll *f = req->f;
    size_t bufsize = fuse_chan_bufsize(req->ch);

    (void) nodeid;
    if (f->debug) {
        printf("INIT: %u.%u\n", arg->major, arg->minor);
        if (arg->major > 7 || (arg->major == 7 && arg->minor >= 6)) {
            printf("flags=0x%08x\n", arg->flags);
            printf("max_readahead=0x%08x\n", arg->max_readahead);