| /* |
| 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/module.h> |
| #include <linux/kernel.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: |
| */ |