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/*
FUSE: Filesystem in Userspace
Copyright (C) 2001 Miklos Szeredi (mszeredi@inf.bme.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>
static int fuse_open(struct inode *inode, struct file *file)
{
struct fuse_conn *fc = INO_FC(inode);
struct fuse_in in = FUSE_IN_INIT;
struct fuse_out out = FUSE_OUT_INIT;
struct fuse_open_in arg;
arg.flags = file->f_flags & ~O_EXCL;
in.h.opcode = FUSE_OPEN;
in.h.ino = inode->i_ino;
in.argsize = sizeof(arg);
in.arg = &arg;
request_send(fc, &in, &out);
if(!out.h.error)
invalidate_inode_pages(inode);
return out.h.error;
}
static int fuse_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
struct fuse_conn *fc = INO_FC(inode);
struct fuse_in in = FUSE_IN_INIT;
struct fuse_out out = FUSE_OUT_INIT;
struct fuse_read_in arg;
char *buffer;
buffer = kmap(page);
arg.offset = page->index << PAGE_CACHE_SHIFT;
arg.size = PAGE_CACHE_SIZE;
in.h.opcode = FUSE_READ;
in.h.ino = inode->i_ino;
in.argsize = sizeof(arg);
in.arg = &arg;
out.argsize = PAGE_CACHE_SIZE;
out.argvar = 1;
out.arg = buffer;
request_send(fc, &in, &out);
if(!out.h.error) {
if(out.argsize < PAGE_CACHE_SIZE)
memset(buffer + out.argsize, 0,
PAGE_CACHE_SIZE - out.argsize);
SetPageUptodate(page);
}
kunmap(page);
UnlockPage(page);
return out.h.error;
}
static int write_buffer(struct inode *inode, struct page *page,
unsigned offset, size_t count)
{
struct fuse_conn *fc = INO_FC(inode);
struct fuse_in in = FUSE_IN_INIT;
struct fuse_out out = FUSE_OUT_INIT;
struct fuse_write_in *arg;
size_t argsize;
char *buffer;
argsize = offsetof(struct fuse_write_in, buf) + count;
arg = kmalloc(argsize, GFP_KERNEL);
if(!arg)
return -ENOMEM;
arg->offset = (page->index << PAGE_CACHE_SHIFT) + offset;
arg->size = count;
buffer = kmap(page);
memcpy(arg->buf, buffer + offset, count);
kunmap(page);
in.h.opcode = FUSE_WRITE;
in.h.ino = inode->i_ino;
in.argsize = argsize;
in.arg = arg;
request_send(fc, &in, &out);
kfree(arg);
return out.h.error;
}
static int fuse_writepage(struct page *page)
{
struct inode *inode = page->mapping->host;
unsigned count;
unsigned long end_index;
int err;
end_index = inode->i_size >> PAGE_CACHE_SHIFT;
if(page->index < end_index)
count = PAGE_CACHE_SIZE;
else {
count = inode->i_size & (PAGE_CACHE_SIZE - 1);
err = -EIO;
if(page->index > end_index || count == 0)
goto out;
}
err = write_buffer(inode, page, 0, count);
out:
UnlockPage(page);
return 0;
}
static int fuse_prepare_write(struct file *file, struct page *page,
unsigned offset, unsigned to)
{
/* No op */
return 0;
}
static int fuse_commit_write(struct file *file, struct page *page,
unsigned offset, unsigned to)
{
int err;
struct inode *inode = page->mapping->host;
err = write_buffer(inode, page, offset, to - offset);
if(!err) {
loff_t pos = (page->index << PAGE_CACHE_SHIFT) + to;
if(pos > inode->i_size)
inode->i_size = pos;
}
return err;
}
static struct file_operations fuse_file_operations = {
open: fuse_open,
read: generic_file_read,
write: generic_file_write,
mmap: generic_file_mmap,
};
static struct address_space_operations fuse_file_aops = {
readpage: fuse_readpage,
writepage: fuse_writepage,
prepare_write: fuse_prepare_write,
commit_write: fuse_commit_write,
};
void fuse_init_file_inode(struct inode *inode)
{
inode->i_fop = &fuse_file_operations;
inode->i_data.a_ops = &fuse_file_aops;
}
/*
* Local Variables:
* indent-tabs-mode: t
* c-basic-offset: 8
* End:
*/
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