fuse.c

Linux下fuse用户文件系统的的源代码

    }

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

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

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

static double diff_timespec(const struct timespec *t1,
                            const struct timespec *t2)
{
    return (t1->tv_sec - t2->tv_sec) + 
        ((double) t1->tv_nsec - (double) t2->tv_nsec) / 1000000000.0;
}

static void open_auto_cache(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
                            const char *path, struct fuse_file_info *fi)
{
    struct node *node;

    pthread_mutex_lock(&f->lock);
    node = get_node(f, ino);
    if (node->cache_valid) {
        struct timespec now;

        curr_time(&now);
        if (diff_timespec(&now, &node->stat_updated) > f->conf.ac_attr_timeout) {
            struct stat stbuf;
            int err;

            pthread_mutex_unlock(&f->lock);
            if (f->op.fgetattr)
                err = fuse_do_fgetattr(f, req, path, &stbuf, fi);
            else
                err = fuse_do_getattr(f, req, path, &stbuf);
            pthread_mutex_lock(&f->lock);

            if (!err)
                update_stat(node, &stbuf);
            else
                node->cache_valid = 0;
        }
    }
    if (node->cache_valid)
        fi->keep_cache = 1;

    node->cache_valid = 1;
    pthread_mutex_unlock(&f->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_compat_open(f, req, 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;

        if (f->conf.auto_cache)
            open_auto_cache(f, req, ino, path, fi);

        /* The reply and the open count increase needs to be under a
           single locked section, otherwise a release could come in
           between and screw up the accounting */
        pthread_mutex_lock(&f->lock);
        if (fuse_reply_open(req, fi) == -ENOENT) {
            /* The open syscall was interrupted, so it must be cancelled */
            pthread_mutex_unlock(&f->lock);
            if(f->op.release && path != NULL)
                fuse_compat_release(f, req, path, fi);
        } else {
            get_node(f, ino)->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_read(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off,
                      struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    char *buf;
    int res;

    buf = (char *) malloc(size);
    if (buf == NULL) {
        reply_err(req, -ENOMEM);
        return;
    }

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("READ[%llu] %lu bytes from %llu\n",
                   (unsigned long long) fi->fh, (unsigned long) size,
                   (unsigned long long) off);
            fflush(stdout);
        }

        res = -ENOSYS;
        if (f->op.read) {
            struct fuse_intr_data d;
            fuse_prepare_interrupt(f, req, &d);
            res = f->op.read(path, buf, size, off, fi);
            fuse_finish_interrupt(f, req, &d);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    if (res >= 0) {
        if (f->conf.debug) {
            printf("   READ[%llu] %u bytes\n", (unsigned long long) fi->fh,
                   res);
            fflush(stdout);
        }
        if ((size_t) res > size)
            fprintf(stderr, "fuse: read too many bytes");
        fuse_reply_buf(req, buf, res);
    } else
        reply_err(req, res);

    free(buf);
}

static void fuse_write(fuse_req_t req, fuse_ino_t ino, const char *buf,
                       size_t size, off_t off, struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int res;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        if (f->conf.debug) {
            printf("WRITE%s[%llu] %lu bytes to %llu\n",
                   fi->writepage ? "PAGE" : "", (unsigned long long) fi->fh,
                   (unsigned long) size, (unsigned long long) off);
            fflush(stdout);
        }

        res = -ENOSYS;
        if (f->op.write) {
            struct fuse_intr_data d;
            fuse_prepare_interrupt(f, req, &d);
            res = f->op.write(path, buf, size, off, fi);
            fuse_finish_interrupt(f, req, &d);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    if (res >= 0) {
        if (f->conf.debug) {
            printf("   WRITE%s[%llu] %u bytes\n",
                   fi->writepage ? "PAGE" : "", (unsigned long long) fi->fh,
                   res);
            fflush(stdout);
        }
        if ((size_t) res > size)
            fprintf(stderr, "fuse: wrote too many bytes");
        fuse_reply_write(req, res);
    } else
        reply_err(req, res);
}

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

    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (f->conf.debug) {
        printf("RELEASE%s[%llu] flags: 0x%x\n", fi->flush ? "+FLUSH" : "", 
               (unsigned long long) fi->fh, fi->flags);
        fflush(stdout);
    }
    if (fi->flush && path && f->op.flush)
        err = fuse_do_flush(f, req, path, fi);
    if (f->op.release)
        fuse_compat_release(f, req, path, fi);

    pthread_mutex_lock(&f->lock);
    node = get_node(f, ino);
    assert(node->open_count > 0);
    --node->open_count;
    if (node->is_hidden && !node->open_count) {
        unlink_hidden = 1;
        node->is_hidden = 0;
    }
    pthread_mutex_unlock(&f->lock);

    if(unlink_hidden && path)
        fuse_do_unlink(f, req, path);

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

    reply_err(req, err);
}

static void fuse_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
                       struct fuse_file_info *fi)
{
    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("FSYNC[%llu]\n", (unsigned long long) fi->fh);
            fflush(stdout);
        }
        err = -ENOSYS;
        if (f->op.fsync) {
            struct fuse_intr_data d;
            fuse_prepare_interrupt(f, req, &d);
            err = f->op.fsync(path, datasync, fi);
            fuse_finish_interrupt(f, req, &d);
        }
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static struct fuse_dirhandle *get_dirhandle(const struct fuse_file_info *llfi,
                                            struct fuse_file_info *fi)
{
    struct fuse_dirhandle *dh = (struct fuse_dirhandle *) (uintptr_t) llfi->fh;
    memset(fi, 0, sizeof(struct fuse_file_info));
    fi->fh = dh->fh;
    fi->fh_old = dh->fh;
    return dh;
}

static void fuse_opendir(fuse_req_t req, fuse_ino_t ino,
                       struct fuse_file_info *llfi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_dirhandle *dh;

    dh = (struct fuse_dirhandle *) malloc(sizeof(struct fuse_dirhandle));
    if (dh == NULL) {
        reply_err(req, -ENOMEM);
        return;
    }
    memset(dh, 0, sizeof(struct fuse_dirhandle));
    dh->fuse = f;
    dh->contents = NULL;
    dh->len = 0;
    dh->filled = 0;
    dh->nodeid = ino;
    fuse_mutex_init(&dh->lock);

    llfi->fh = (uintptr_t) dh;

    if (f->op.opendir) {
        struct fuse_file_info fi;
        char *path;
        int err;

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

        err = -ENOENT;
        pthread_rwlock_rdlock(&f->tree_lock);
        path = get_path(f, ino);
        if (path != NULL) {
            err = fuse_compat_opendir(f, req, path, &fi);
            dh->fh = fi.fh;
        }
        if (!err) {
            if (fuse_reply_open(req, llfi) == -ENOENT) {
                /* The opendir syscall was interrupted, so it must be
                   cancelled */
                if(f->op.releasedir)
                    fuse_do_releasedir(f, req, path, &fi);
                pthread_mutex_destroy(&dh->lock);
                free(dh);
            }
        } else {
            reply_err(req, err);
            free(dh);
        }
        free(path);
        pthread_rwlock_unlock(&f->tree_lock);
    } else
        fuse_reply_open(req, llfi);
}

static int extend_contents(struct fuse_dirhandle *dh, unsigned minsize)
{
    if (minsize > dh->size) {
        char *newptr;
        unsigned newsize = dh->size;
        if (!newsize)
            newsize = 1024;
        while (newsize < minsize)
            newsize *= 2;

        newptr = (char *) realloc(dh->contents, newsize);
        if (!newptr) {
            dh->error = -ENOMEM;
            return -1;
        }
        dh->contents = newptr;
        dh->size = newsize;
    }
    return 0;
}

static int fill_dir_common(struct fuse_dirhandle *dh, const char *name,
                           const struct stat *statp, off_t off)
{
    struct stat stbuf;
    size_t newlen;

    if (statp)
        stbuf = *statp;
    else {
        memset(&stbuf, 0, sizeof(stbuf));
        stbuf.st_ino = FUSE_UNKNOWN_INO;
    }

    if (!dh->fuse->conf.use_ino) {
        stbuf.st_ino = FUSE_UNKNOWN_INO;
        if (dh->fuse->conf.readdir_ino) {
            struct node *node;
            pthread_mutex_lock(&dh->fuse->lock);
            node = lookup_node(dh->fuse, dh->nodeid, name);
            if (node)
                stbuf.st_ino  = (ino_t) node->nodeid;
            pthread_mutex_unlock(&dh->fuse->lock);
        }
    }

    if (off) {
        if (extend_contents(dh, dh->needlen) == -1)
            return 1;

        dh->filled = 0;
        newlen = dh->len + fuse_add_direntry(dh->req, dh->contents + dh->len,
                                             dh->needlen - dh->len, name,
                                             &stbuf, off);
        if (newlen > dh->needlen)
            return 1;
    } else {
        newlen = dh->len + fuse_add_direntry(dh->req, NULL, 0, name, NULL, 0);
        if (extend_contents(dh, newlen) == -1)
            return 1;

        fuse_add_direntry(dh->req, dh->contents + dh->len, dh->size - dh->len,
                          name, &stbuf, newlen);
    }
    dh->len = newlen;
    return 0;
}

static int fill_dir(void *buf, const char *name, const struct stat *stbuf,
                    off_t off)
{
    return fill_dir_common((struct fuse_dirhandle *) buf, name, stbuf, off);
}

static int fill_dir_old(struct fuse_dirhandle *dh, const char *name, int type,
                        ino_t ino)
{
    struct stat stbuf;

    memset(&stbuf, 0, sizeof(stbuf));
    stbuf.st_mode = type << 12;
    stbuf.st_ino = ino;

    fill_dir_common(dh, name, &stbuf, 0);
    return dh->error;
}

static int readdir_fill(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
                        size_t size, off_t off, struct fuse_dirhandle *dh,
                        struct fuse_file_info *fi)
{
    int err = -ENOENT;
    char *path;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        dh->len = 0;
        dh->error = 0;
        dh->needlen = size;
        dh->filled = 1;
        dh->req = req;
        err = -ENOSYS;
        if (f->op.readdir) {
            struct fuse_intr_data d;
            fuse_prepare_interrupt(f, req, &d);
            err = f->op.readdir(path, dh, fill_dir, off, fi);
            fuse_finish_interrupt(f, req, &d);
        } else if (f->op.getdir) {
            struct fuse_intr_data d;
            fuse_prepare_interrupt(f, req, &d);
            err = f->op.getdir(path, dh, fill_dir_old);
            fuse_finish_interrupt(f, req, &d);
        }
        dh->req = NULL;
        if (!err)
            err = dh->error;
        if (err)
            dh->filled = 0;
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    return err;
}

static void fuse_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
                         off_t off, struct fuse_file_info *llfi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_file_info fi;