fuse.c

linux下的用户文件系统fuse-2.5.2

                        int err)
{
    if (!err) {
        if (fuse_reply_entry(req, e) == -ENOENT)
            forget_node(req_fuse(req), e->ino, 1);
    } else
        reply_err(req, err);
}

static void fuse_data_init(void *data)
{
    struct fuse *f = (struct fuse *) data;
    struct fuse_context *c = fuse_get_context();

    memset(c, 0, sizeof(*c));
    c->fuse = f;

    if (f->op.init)
        f->user_data = f->op.init();
}

static void fuse_data_destroy(void *data)
{
    struct fuse *f = (struct fuse *) data;
    struct fuse_context *c = fuse_get_context();

    memset(c, 0, sizeof(*c));
    c->fuse = f;
    c->private_data = f->user_data;

    if (f->op.destroy)
        f->op.destroy(f->user_data);
}

static void fuse_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_entry_param e;
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("LOOKUP %s\n", path);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.getattr) {
            err = lookup_path(f, parent, name, path, &e, NULL);
            if (err == -ENOENT && f->conf.negative_timeout != 0.0) {
                e.ino = 0;
                e.entry_timeout = f->conf.negative_timeout;
                err = 0;
            }
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_entry(req, &e, err);
}

static void fuse_forget(fuse_req_t req, fuse_ino_t ino, unsigned long nlookup)
{
    struct fuse *f = req_fuse(req);
    if (f->conf.debug) {
        printf("FORGET %llu/%lu\n", (unsigned long long) ino, nlookup);
        fflush(stdout);
    }
    forget_node(f, ino, nlookup);
    fuse_reply_none(req);
}

static void fuse_getattr(fuse_req_t req, fuse_ino_t ino,
                         struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct stat buf;
    char *path;
    int err;

    (void) fi;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        err = -ENOSYS;
        if (f->op.getattr)
            err = f->op.getattr(path, &buf);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    if (!err) {
        set_stat(f, ino, &buf);
        fuse_reply_attr(req, &buf, f->conf.attr_timeout);
    } else
        reply_err(req, err);
}

static int do_chmod(struct fuse *f, const char *path, struct stat *attr)
{
    int err;

    err = -ENOSYS;
    if (f->op.chmod)
        err = f->op.chmod(path, attr->st_mode);

    return err;
}

static int do_chown(struct fuse *f, const char *path, struct stat *attr,
                    int valid)
{
    int err;
    uid_t uid = (valid & FUSE_SET_ATTR_UID) ? attr->st_uid : (uid_t) -1;
    gid_t gid = (valid & FUSE_SET_ATTR_GID) ? attr->st_gid : (gid_t) -1;

    err = -ENOSYS;
    if (f->op.chown)
        err = f->op.chown(path, uid, gid);

    return err;
}

static int do_truncate(struct fuse *f, const char *path, struct stat *attr,
                       struct fuse_file_info *fi)
{
    int err;

    err = -ENOSYS;
    if (fi && f->op.ftruncate)
        err = f->op.ftruncate(path, attr->st_size, fi);
    else if (f->op.truncate)
        err = f->op.truncate(path, attr->st_size);

    return err;
}

static int do_utime(struct fuse *f, const char *path, struct stat *attr)
{
    int err;
    struct utimbuf buf;
    buf.actime = attr->st_atime;
    buf.modtime = attr->st_mtime;
    err = -ENOSYS;
    if (f->op.utime)
        err = f->op.utime(path, &buf);

    return err;
}

static void fuse_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
                         int valid, struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct stat buf;
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        err = -ENOSYS;
        if (f->op.getattr) {
            err = 0;
            if (!err && (valid & FUSE_SET_ATTR_MODE))
                err = do_chmod(f, path, attr);
            if (!err && (valid & (FUSE_SET_ATTR_UID | FUSE_SET_ATTR_GID)))
                err = do_chown(f, path, attr, valid);
            if (!err && (valid & FUSE_SET_ATTR_SIZE))
                err = do_truncate(f, path, attr, fi);
            if (!err && (valid & (FUSE_SET_ATTR_ATIME | FUSE_SET_ATTR_MTIME)) == (FUSE_SET_ATTR_ATIME | FUSE_SET_ATTR_MTIME))
                err = do_utime(f, path, attr);
            if (!err)
                err = f->op.getattr(path, &buf);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    if (!err) {
        set_stat(f, ino, &buf);
        fuse_reply_attr(req, &buf, f->conf.attr_timeout);
    } else
        reply_err(req, err);
}

static void fuse_access(fuse_req_t req, fuse_ino_t ino, int mask)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("ACCESS %s 0%o\n", path, mask);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.access)
            err = f->op.access(path, mask);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static void fuse_readlink(fuse_req_t req, fuse_ino_t ino)
{
    struct fuse *f = req_fuse_prepare(req);
    char linkname[PATH_MAX + 1];
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        err = -ENOSYS;
        if (f->op.readlink)
            err = f->op.readlink(path, linkname, sizeof(linkname));
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    if (!err) {
        linkname[PATH_MAX] = '\0';
        fuse_reply_readlink(req, linkname);
    } else
        reply_err(req, err);
}

static void fuse_mknod(fuse_req_t req, fuse_ino_t parent, const char *name,
                       mode_t mode, dev_t rdev)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_entry_param e;
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("MKNOD %s\n", path);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (S_ISREG(mode) && f->op.create && f->op.getattr) {
            struct fuse_file_info fi;

            memset(&fi, 0, sizeof(fi));
            fi.flags = O_CREAT | O_EXCL | O_WRONLY;
            err = f->op.create(path, mode, &fi);
            if (!err) {
                err = lookup_path(f, parent, name, path, &e, &fi);
                if (f->op.release)
                    f->op.release(path, &fi);
            }
        } else if (f->op.mknod && f->op.getattr) {
            err = f->op.mknod(path, mode, rdev);
            if (!err)
                err = lookup_path(f, parent, name, path, &e, NULL);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_entry(req, &e, err);
}

static void fuse_mkdir(fuse_req_t req, fuse_ino_t parent, const char *name,
                       mode_t mode)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_entry_param e;
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("MKDIR %s\n", path);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.mkdir && f->op.getattr) {
            err = f->op.mkdir(path, mode);
            if (!err)
                err = lookup_path(f, parent, name, path, &e, NULL);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_entry(req, &e, err);
}

static void fuse_unlink(fuse_req_t req, fuse_ino_t parent, const char *name)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_wrlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("UNLINK %s\n", path);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.unlink) {
            if (!f->conf.hard_remove && is_open(f, parent, name))
                err = hide_node(f, path, parent, name);
            else {
                err = f->op.unlink(path);
                if (!err)
                    remove_node(f, parent, name);
            }
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static void fuse_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_wrlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("RMDIR %s\n", path);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.rmdir) {
            err = f->op.rmdir(path);
            if (!err)
                remove_node(f, parent, name);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static void fuse_symlink(fuse_req_t req, const char *linkname,
                         fuse_ino_t parent, const char *name)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_entry_param e;
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("SYMLINK %s\n", path);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.symlink && f->op.getattr) {
            err = f->op.symlink(linkname, path);
            if (!err)
                err = lookup_path(f, parent, name, path, &e, NULL);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_entry(req, &e, err);
}

static void fuse_rename(fuse_req_t req, fuse_ino_t olddir, const char *oldname,
                        fuse_ino_t newdir, const char *newname)
{
    struct fuse *f = req_fuse_prepare(req);
    char *oldpath;
    char *newpath;
    int err;

    err = -ENOENT;
    pthread_rwlock_wrlock(&f->tree_lock);
    oldpath = get_path_name(f, olddir, oldname);
    if (oldpath != NULL) {
        newpath = get_path_name(f, newdir, newname);
        if (newpath != NULL) {
            if (f->conf.debug) {
                printf("RENAME %s -> %s\n", oldpath, newpath);
                fflush(stdout);
            }
            err = -ENOSYS;
            if (f->op.rename) {
                err = 0;
                if (!f->conf.hard_remove &&
                    is_open(f, newdir, newname))
                    err = hide_node(f, newpath, newdir, newname);
                if (!err) {
                    err = f->op.rename(oldpath, newpath);
                    if (!err)
                        err = rename_node(f, olddir, oldname, newdir, newname, 0);
                }
            }
            free(newpath);
        }
        free(oldpath);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static void fuse_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t newparent,
                      const char *newname)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_entry_param e;
    char *oldpath;
    char *newpath;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    oldpath = get_path(f, ino);
    if (oldpath != NULL) {
        newpath =  get_path_name(f, newparent, newname);
        if (newpath != NULL) {
            if (f->conf.debug) {
                printf("LINK %s\n", newpath);
                fflush(stdout);
            }
            err = -ENOSYS;
            if (f->op.link && f->op.getattr) {
                err = f->op.link(oldpath, newpath);
                if (!err)
                    err = lookup_path(f, newparent, newname, newpath, &e, NULL);
            }
            free(newpath);
        }
        free(oldpath);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_entry(req, &e, err);
}

static void fuse_create(fuse_req_t req, fuse_ino_t parent, const char *name,
                        mode_t mode, struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_entry_param e;
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path_name(f, parent, name);
    if (path != NULL) {
        err = -ENOSYS;
        if (f->op.create && f->op.getattr) {
            err = f->op.create(path, mode, fi);
            if (!err) {
                if (f->conf.debug) {
                    printf("CREATE[%llu] flags: 0x%x %s\n",
                           (unsigned long long) fi->fh, fi->flags, path);
                    fflush(stdout);
                }
                err = lookup_path(f, parent, name, path, &e, fi);
                if (err) {
                    if (f->op.release)
                        f->op.release(path, fi);
                } else if (!S_ISREG(e.attr.st_mode)) {
                    err = -EIO;
                    if (f->op.release)
                        f->op.release(path, fi);
                    forget_node(f, e.ino, 1);
                }
            }
        }
    }

    if (!err) {
        if (f->conf.direct_io)
            fi->direct_io = 1;
        if (f->conf.kernel_cache)
            fi->keep_cache = 1;

        pthread_mutex_lock(&f->lock);
        if (fuse_reply_create(req, &e, fi) == -ENOENT) {
            /* The open syscall was interrupted, so it must be cancelled */
            if(f->op.release)
                f->op.release(path, fi);
            forget_node(f, e.ino, 1);
        } else {
            struct node *node = get_node(f, e.ino);
            node->open_count ++;
        }
        pthread_mutex_unlock(&f->lock);
    } else
        reply_err(req, err);

    if (path)
        free(path);
    pthread_rwlock_unlock(&f->tree_lock);
}

static void fuse_open(fuse_req_t req, fuse_ino_t ino,
                      struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path = NULL;
    int err = 0;

    pthread_rwlock_rdlock(&f->tree_lock);
    if (f->op.open) {
        err = -ENOENT;
        path = get_path(f, ino);
        if (path != NULL)
            err = fuse_do_open(f, path, fi);
    }
    if (!err) {
        if (f->conf.debug) {
            printf("OPEN[%llu] flags: 0x%x\n", (unsigned long long) fi->fh,
                   fi->flags);
            fflush(stdout);
        }

        if (f->conf.direct_io)
            fi->direct_io = 1;
        if (f->conf.kernel_cache)
            fi->keep_cache = 1;

        pthread_mutex_lock(&f->lock);