/*  FUSE: Filesystem in Userspace  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>  This program can be distributed under the terms of the GNU GPL.  See the file COPYING.*/#include "fuse_i.h"#include <linux/pagemap.h>#include <linux/slab.h>#include <linux/kernel.h>#include <linux/sched.h>#ifndef KERNEL_2_6_11_PLUSstatic inline loff_t page_offset(struct page *page){	return ((loff_t)page->index) << PAGE_CACHE_SHIFT;}#endifstatic struct file_operations fuse_direct_io_file_operations;static int fuse_send_open(struct inode *inode, struct file *file, int isdir,			  struct fuse_open_out *outargp){	struct fuse_conn *fc = get_fuse_conn(inode);	struct fuse_open_in inarg;	struct fuse_req *req;	int err;	req = fuse_get_req(fc);	if (IS_ERR(req))		return PTR_ERR(req);	memset(&inarg, 0, sizeof(inarg));	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);	req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;	req->in.h.nodeid = get_node_id(inode);	req->in.numargs = 1;	req->in.args[0].size = sizeof(inarg);	req->in.args[0].value = &inarg;	req->out.numargs = 1;	req->out.args[0].size = sizeof(*outargp);	req->out.args[0].value = outargp;	request_send(fc, req);	err = req->out.h.error;	fuse_put_request(fc, req);	return err;}struct fuse_file *fuse_file_alloc(void){	struct fuse_file *ff;	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);	if (ff) {		ff->reserved_req = fuse_request_alloc();		if (!ff->reserved_req) {			kfree(ff);			ff = NULL;		}	}	return ff;}void fuse_file_free(struct fuse_file *ff){	fuse_request_free(ff->reserved_req);	kfree(ff);}void fuse_finish_open(struct inode *inode, struct file *file,		      struct fuse_file *ff, struct fuse_open_out *outarg){	if (outarg->open_flags & FOPEN_DIRECT_IO)		file->f_op = &fuse_direct_io_file_operations;	if (!(outarg->open_flags & FOPEN_KEEP_CACHE))#ifdef KERNEL_2_6_21_PLUS		invalidate_mapping_pages(inode->i_mapping, 0, -1);#else		invalidate_inode_pages(inode->i_mapping);#endif	ff->fh = outarg->fh;	file->private_data = ff;}int fuse_open_common(struct inode *inode, struct file *file, int isdir){	struct fuse_open_out outarg;	struct fuse_file *ff;	int err;	/* VFS checks this, but only _after_ ->open() */	if (file->f_flags & O_DIRECT)		return -EINVAL;	err = generic_file_open(inode, file);	if (err)		return err;	/* If opening the root node, no lookup has been performed on	   it, so the attributes must be refreshed */	if (get_node_id(inode) == FUSE_ROOT_ID) {		err = fuse_do_getattr(inode);		if (err)		 	return err;	}	ff = fuse_file_alloc();	if (!ff)		return -ENOMEM;	err = fuse_send_open(inode, file, isdir, &outarg);	if (err)		fuse_file_free(ff);	else {		if (isdir)			outarg.open_flags &= ~FOPEN_DIRECT_IO;		fuse_finish_open(inode, file, ff, &outarg);	}	return err;}struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,				   int opcode){	struct fuse_req *req = ff->reserved_req;	struct fuse_release_in *inarg = &req->misc.release_in;	inarg->fh = ff->fh;	inarg->flags = flags;	req->in.h.opcode = opcode;	req->in.h.nodeid = nodeid;	req->in.numargs = 1;	req->in.args[0].size = sizeof(struct fuse_release_in);	req->in.args[0].value = inarg;	kfree(ff);	return req;}int fuse_release_common(struct inode *inode, struct file *file, int isdir){	struct fuse_file *ff = file->private_data;	if (ff) {		struct fuse_conn *fc = get_fuse_conn(inode);		struct fuse_req *req;		req = fuse_release_fill(ff, get_node_id(inode), file->f_flags,					isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);		/* Hold vfsmount and dentry until release is finished */		req->vfsmount = mntget(file->f_vfsmnt);		req->dentry = dget(file->f_dentry);		request_send_background(fc, req);	}	/* Return value is ignored by VFS */	return 0;}static int fuse_open(struct inode *inode, struct file *file){	return fuse_open_common(inode, file, 0);}static int fuse_release(struct inode *inode, struct file *file){	return fuse_release_common(inode, file, 0);}/* * Scramble the ID space with XTEA, so that the value of the files_struct * pointer is not exposed to userspace. */static u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id){	u32 *k = fc->scramble_key;	u64 v = (unsigned long) id;	u32 v0 = v;	u32 v1 = v >> 32;	u32 sum = 0;	int i;	for (i = 0; i < 32; i++) {		v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);		sum += 0x9E3779B9;		v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);	}	return (u64) v0 + ((u64) v1 << 32);}#ifdef KERNEL_2_6_18_PLUSstatic int fuse_flush(struct file *file, fl_owner_t id)#elsestatic int fuse_flush(struct file *file)#endif{	struct inode *inode = file->f_dentry->d_inode;	struct fuse_conn *fc = get_fuse_conn(inode);	struct fuse_file *ff = file->private_data;	struct fuse_req *req;	struct fuse_flush_in inarg;	int err;	if (is_bad_inode(inode))		return -EIO;	if (fc->no_flush)		return 0;	req = fuse_get_req_nofail(fc, file);	memset(&inarg, 0, sizeof(inarg));	inarg.fh = ff->fh;#ifdef KERNEL_2_6_18_PLUS	inarg.lock_owner = fuse_lock_owner_id(fc, id);#else	inarg.lock_owner = fuse_lock_owner_id(fc, NULL);#endif	req->in.h.opcode = FUSE_FLUSH;	req->in.h.nodeid = get_node_id(inode);	req->in.numargs = 1;	req->in.args[0].size = sizeof(inarg);	req->in.args[0].value = &inarg;	req->force = 1;	request_send(fc, req);	err = req->out.h.error;	fuse_put_request(fc, req);	if (err == -ENOSYS) {		fc->no_flush = 1;		err = 0;	}	return err;}int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,		      int isdir){	struct inode *inode = de->d_inode;	struct fuse_conn *fc = get_fuse_conn(inode);	struct fuse_file *ff = file->private_data;	struct fuse_req *req;	struct fuse_fsync_in inarg;	int err;	if (is_bad_inode(inode))		return -EIO;	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))		return 0;	req = fuse_get_req(fc);	if (IS_ERR(req))		return PTR_ERR(req);	memset(&inarg, 0, sizeof(inarg));	inarg.fh = ff->fh;	inarg.fsync_flags = datasync ? 1 : 0;	req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;	req->in.h.nodeid = get_node_id(inode);	req->in.numargs = 1;	req->in.args[0].size = sizeof(inarg);	req->in.args[0].value = &inarg;	request_send(fc, req);	err = req->out.h.error;	fuse_put_request(fc, req);	if (err == -ENOSYS) {		if (isdir)			fc->no_fsyncdir = 1;		else			fc->no_fsync = 1;		err = 0;	}	return err;}static int fuse_fsync(struct file *file, struct dentry *de, int datasync){	return fuse_fsync_common(file, de, datasync, 0);}void fuse_read_fill(struct fuse_req *req, struct file *file,		    struct inode *inode, loff_t pos, size_t count, int opcode){	struct fuse_file *ff = file->private_data;	struct fuse_read_in *inarg = &req->misc.read_in;	inarg->fh = ff->fh;	inarg->offset = pos;	inarg->size = count;	req->in.h.opcode = opcode;	req->in.h.nodeid = get_node_id(inode);	req->in.numargs = 1;	req->in.args[0].size = sizeof(struct fuse_read_in);	req->in.args[0].value = inarg;	req->out.argpages = 1;	req->out.argvar = 1;	req->out.numargs = 1;	req->out.args[0].size = count;}static size_t fuse_send_read(struct fuse_req *req, struct file *file,			     struct inode *inode, loff_t pos, size_t count){	struct fuse_conn *fc = get_fuse_conn(inode);	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);	request_send(fc, req);	return req->out.args[0].size;}static int fuse_readpage(struct file *file, struct page *page){	struct inode *inode = page->mapping->host;	struct fuse_conn *fc = get_fuse_conn(inode);	struct fuse_req *req;	int err;	err = -EIO;	if (is_bad_inode(inode))		goto out;	req = fuse_get_req(fc);	err = PTR_ERR(req);	if (IS_ERR(req))		goto out;	req->out.page_zeroing = 1;	req->num_pages = 1;	req->pages[0] = page;	fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE);	err = req->out.h.error;	fuse_put_request(fc, req);	if (!err)		SetPageUptodate(page);	fuse_invalidate_attr(inode); /* atime changed */ out:	unlock_page(page);	return err;}static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req){	int i;	fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */	for (i = 0; i < req->num_pages; i++) {		struct page *page = req->pages[i];		if (!req->out.h.error)			SetPageUptodate(page);		else			SetPageError(page);		unlock_page(page);	}	fuse_put_request(fc, req);}static void fuse_send_readpages(struct fuse_req *req, struct file *file,				struct inode *inode){	struct fuse_conn *fc = get_fuse_conn(inode);	loff_t pos = page_offset(req->pages[0]);	size_t count = req->num_pages << PAGE_CACHE_SHIFT;	req->out.page_zeroing = 1;	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);	if (fc->async_read) {		get_file(file);		req->file = file;		req->end = fuse_readpages_end;		request_send_background(fc, req);	} else {		request_send(fc, req);		fuse_readpages_end(fc, req);	}}struct fuse_readpages_data {	struct fuse_req *req;	struct file *file;	struct inode *inode;};static int fuse_readpages_fill(void *_data, struct page *page){	struct fuse_readpages_data *data = _data;	struct fuse_req *req = data->req;	struct inode *inode = data->inode;	struct fuse_conn *fc = get_fuse_conn(inode);	int err;	if (req && req->num_pages &&	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {		fuse_send_readpages(req, data->file, inode);		req = NULL;	}	if (!req) {		err = -EIO;		if (is_bad_inode(inode))			goto out_unlock_page;		data->req = req = fuse_get_req(fc);		err = PTR_ERR(req);		if (IS_ERR(req))			goto out_unlock_page;	}	req->pages[req->num_pages] = page;	req->num_pages ++;	return 0; out_unlock_page:	unlock_page(page);	return err;}static int fuse_readpages(struct file *file, struct address_space *mapping,			  struct list_head *pages, unsigned nr_pages){	struct inode *inode = mapping->host;	struct fuse_conn *fc = get_fuse_conn(inode);	struct fuse_readpages_data data;	int err;	data.file = file;	data.inode = inode;	data.req = NULL;	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);	if (!err && data.req) {		if (data.req->num_pages)			fuse_send_readpages(data.req, file, inode);		else			fuse_put_request(fc, data.req);	}	return err;}static size_t fuse_send_write(struct fuse_req *req, struct file *file,			      struct inode *inode, loff_t pos, size_t count){	struct fuse_conn *fc = get_fuse_conn(inode);	struct fuse_file *ff = file->private_data;	struct fuse_write_in inarg;	struct fuse_write_out outarg;	memset(&inarg, 0, sizeof(struct fuse_write_in));	inarg.fh = ff->fh;