[PATCH] hostap: Add support for WE-19

[linux-2.6/kvm.git] / fs / fuse / file.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2005  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>

static struct file_operations fuse_direct_io_file_operations;

int fuse_open_common(struct inode *inode, struct file *file, int isdir)
{
        struct fuse_conn *fc = get_fuse_conn(inode);
        struct fuse_req *req;
        struct fuse_open_in inarg;
        struct fuse_open_out outarg;
        struct fuse_file *ff;
        int err;

        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) {
                int err = fuse_do_getattr(inode);
                if (err)
                        return err;
        }

        req = fuse_get_request(fc);
        if (!req)
                return -EINTR;

        err = -ENOMEM;
        ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
        if (!ff)
                goto out_put_request;

        ff->release_req = fuse_request_alloc();
        if (!ff->release_req) {
                kfree(ff);
                goto out_put_request;
        }

        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->inode = 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(outarg);
        req->out.args[0].value = &outarg;
        request_send(fc, req);
        err = req->out.h.error;
        if (err) {
                fuse_request_free(ff->release_req);
                kfree(ff);
        } else {
                if (!isdir && (outarg.open_flags & FOPEN_DIRECT_IO))
                        file->f_op = &fuse_direct_io_file_operations;
                if (!(outarg.open_flags & FOPEN_KEEP_CACHE))
                        invalidate_inode_pages(inode->i_mapping);
                ff->fh = outarg.fh;
                file->private_data = ff;
        }

 out_put_request:
        fuse_put_request(fc, req);
        return err;
}

int fuse_release_common(struct inode *inode, struct file *file, int isdir)
{
        struct fuse_conn *fc = get_fuse_conn(inode);
        struct fuse_file *ff = file->private_data;
        struct fuse_req *req = ff->release_req;
        struct fuse_release_in *inarg = &req->misc.release_in;

        inarg->fh = ff->fh;
        inarg->flags = file->f_flags & ~O_EXCL;
        req->in.h.opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
        req->in.h.nodeid = get_node_id(inode);
        req->inode = inode;
        req->in.numargs = 1;
        req->in.args[0].size = sizeof(struct fuse_release_in);
        req->in.args[0].value = inarg;
        request_send_background(fc, req);
        kfree(ff);

        /* 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);
}

static int fuse_flush(struct file *file)
{
        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 (fc->no_flush)
                return 0;

        req = fuse_get_request(fc);
        if (!req)
                return -EINTR;

        memset(&inarg, 0, sizeof(inarg));
        inarg.fh = ff->fh;
        req->in.h.opcode = FUSE_FLUSH;
        req->in.h.nodeid = get_node_id(inode);
        req->inode = inode;
        req->file = file;
        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) {
                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 ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
                return 0;

        req = fuse_get_request(fc);
        if (!req)
                return -EINTR;

        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->inode = inode;
        req->file = file;
        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);
}

size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
                             struct inode *inode, loff_t pos, size_t count,
                             int isdir)
{
        struct fuse_conn *fc = get_fuse_conn(inode);
        struct fuse_file *ff = file->private_data;
        struct fuse_read_in inarg;

        memset(&inarg, 0, sizeof(struct fuse_read_in));
        inarg.fh = ff->fh;
        inarg.offset = pos;
        inarg.size = count;
        req->in.h.opcode = isdir ? FUSE_READDIR : FUSE_READ;
        req->in.h.nodeid = get_node_id(inode);
        req->inode = inode;
        req->file = file;
        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;
        request_send(fc, req);
        return req->out.args[0].size;
}

static inline size_t fuse_send_read(struct fuse_req *req, struct file *file,
                                    struct inode *inode, loff_t pos,
                                    size_t count)
{
        return fuse_send_read_common(req, file, inode, pos, count, 0);
}

static int fuse_readpage(struct file *file, struct page *page)
{
        struct inode *inode = page->mapping->host;
        struct fuse_conn *fc = get_fuse_conn(inode);
        loff_t pos = (loff_t) page->index << PAGE_CACHE_SHIFT;
        struct fuse_req *req = fuse_get_request(fc);
        int err = -EINTR;
        if (!req)
                goto out;

        req->out.page_zeroing = 1;
        req->num_pages = 1;
        req->pages[0] = page;
        fuse_send_read(req, file, inode, pos, 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 int fuse_send_readpages(struct fuse_req *req, struct file *file,
                               struct inode *inode)
{
        loff_t pos = (loff_t) req->pages[0]->index << PAGE_CACHE_SHIFT;
        size_t count = req->num_pages << PAGE_CACHE_SHIFT;
        unsigned i;
        req->out.page_zeroing = 1;
        fuse_send_read(req, file, inode, pos, count);
        for (i = 0; i < req->num_pages; i++) {
                struct page *page = req->pages[i];
                if (!req->out.h.error)
                        SetPageUptodate(page);
                unlock_page(page);
        }
        return req->out.h.error;
}

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);

        if (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)) {
                int err = fuse_send_readpages(req, data->file, inode);
                if (err) {
                        unlock_page(page);
                        return err;
                }
                fuse_reset_request(req);
        }
        req->pages[req->num_pages] = page;
        req->num_pages ++;
        return 0;
}

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 = fuse_get_request(fc);
        if (!data.req)
                return -EINTR;

        err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
        if (!err && data.req->num_pages)
                err = fuse_send_readpages(data.req, file, inode);
        fuse_put_request(fc, data.req);
        fuse_invalidate_attr(inode); /* atime changed */
        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;
        inarg.offset = pos;
        inarg.size = count;
        req->in.h.opcode = FUSE_WRITE;
        req->in.h.nodeid = get_node_id(inode);
        req->inode = inode;
        req->file = file;
        req->in.argpages = 1;
        req->in.numargs = 2;
        req->in.args[0].size = sizeof(struct fuse_write_in);
        req->in.args[0].value = &inarg;
        req->in.args[1].size = count;
        req->out.numargs = 1;
        req->out.args[0].size = sizeof(struct fuse_write_out);
        req->out.args[0].value = &outarg;
        request_send(fc, req);
        return outarg.size;
}

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;
        size_t nres;
        unsigned count = to - offset;
        struct inode *inode = page->mapping->host;
        struct fuse_conn *fc = get_fuse_conn(inode);
        loff_t pos = ((loff_t) page->index << PAGE_CACHE_SHIFT) + offset;
        struct fuse_req *req = fuse_get_request(fc);
        if (!req)
                return -EINTR;

        req->num_pages = 1;
        req->pages[0] = page;
        req->page_offset = offset;
        nres = fuse_send_write(req, file, inode, pos, count);
        err = req->out.h.error;
        fuse_put_request(fc, req);
        if (!err && nres != count)
                err = -EIO;
        if (!err) {
                pos += count;
                if (pos > i_size_read(inode))
                        i_size_write(inode, pos);

                if (offset == 0 && to == PAGE_CACHE_SIZE) {
                        clear_page_dirty(page);
                        SetPageUptodate(page);
                }
        }
        fuse_invalidate_attr(inode);
        return err;
}

static void fuse_release_user_pages(struct fuse_req *req, int write)
{
        unsigned i;

        for (i = 0; i < req->num_pages; i++) {
                struct page *page = req->pages[i];
                if (write)
                        set_page_dirty_lock(page);
                put_page(page);
        }
}

static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
                               unsigned nbytes, int write)
{
        unsigned long user_addr = (unsigned long) buf;
        unsigned offset = user_addr & ~PAGE_MASK;
        int npages;

        /* This doesn't work with nfsd */
        if (!current->mm)
                return -EPERM;

        nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
        npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
        npages = min(npages, FUSE_MAX_PAGES_PER_REQ);
        down_read(&current->mm->mmap_sem);
        npages = get_user_pages(current, current->mm, user_addr, npages, write,
                                0, req->pages, NULL);
        up_read(&current->mm->mmap_sem);
        if (npages < 0)
                return npages;

        req->num_pages = npages;
        req->page_offset = offset;
        return 0;
}

static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
                              size_t count, loff_t *ppos, int write)
{
        struct inode *inode = file->f_dentry->d_inode;
        struct fuse_conn *fc = get_fuse_conn(inode);
        size_t nmax = write ? fc->max_write : fc->max_read;
        loff_t pos = *ppos;
        ssize_t res = 0;
        struct fuse_req *req = fuse_get_request(fc);
        if (!req)
                return -EINTR;

        while (count) {
                size_t tmp;
                size_t nres;
                size_t nbytes = min(count, nmax);
                int err = fuse_get_user_pages(req, buf, nbytes, !write);
                if (err) {
                        res = err;
                        break;
                }
                tmp = (req->num_pages << PAGE_SHIFT) - req->page_offset;
                nbytes = min(nbytes, tmp);
                if (write)
                        nres = fuse_send_write(req, file, inode, pos, nbytes);
                else
                        nres = fuse_send_read(req, file, inode, pos, nbytes);
                fuse_release_user_pages(req, !write);
                if (req->out.h.error) {
                        if (!res)
                                res = req->out.h.error;
                        break;
                } else if (nres > nbytes) {
                        res = -EIO;
                        break;
                }
                count -= nres;
                res += nres;
                pos += nres;
                buf += nres;
                if (nres != nbytes)
                        break;
                if (count)
                        fuse_reset_request(req);
        }
        fuse_put_request(fc, req);
        if (res > 0) {
                if (write && pos > i_size_read(inode))
                        i_size_write(inode, pos);
                *ppos = pos;
        }
        fuse_invalidate_attr(inode);

        return res;
}

static ssize_t fuse_direct_read(struct file *file, char __user *buf,
                                     size_t count, loff_t *ppos)
{
        return fuse_direct_io(file, buf, count, ppos, 0);
}

static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
{
        struct inode *inode = file->f_dentry->d_inode;
        ssize_t res;
        /* Don't allow parallel writes to the same file */
        down(&inode->i_sem);
        res = fuse_direct_io(file, buf, count, ppos, 1);
        up(&inode->i_sem);
        return res;
}

static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
        if ((vma->vm_flags & VM_SHARED)) {
                if ((vma->vm_flags & VM_WRITE))
                        return -ENODEV;
                else
                        vma->vm_flags &= ~VM_MAYWRITE;
        }
        return generic_file_mmap(file, vma);
}

static int fuse_set_page_dirty(struct page *page)
{
        printk("fuse_set_page_dirty: should not happen\n");
        dump_stack();
        return 0;
}

static struct file_operations fuse_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = generic_file_read,
        .write          = generic_file_write,
        .mmap           = fuse_file_mmap,
        .open           = fuse_open,
        .flush          = fuse_flush,
        .release        = fuse_release,
        .fsync          = fuse_fsync,
        .sendfile       = generic_file_sendfile,
};

static struct file_operations fuse_direct_io_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = fuse_direct_read,
        .write          = fuse_direct_write,
        .open           = fuse_open,
        .flush          = fuse_flush,
        .release        = fuse_release,
        .fsync          = fuse_fsync,
        /* no mmap and sendfile */
};

static struct address_space_operations fuse_file_aops  = {
        .readpage       = fuse_readpage,
        .prepare_write  = fuse_prepare_write,
        .commit_write   = fuse_commit_write,
        .readpages      = fuse_readpages,
        .set_page_dirty = fuse_set_page_dirty,
};

void fuse_init_file_inode(struct inode *inode)
{
        inode->i_fop = &fuse_file_operations;
        inode->i_data.a_ops = &fuse_file_aops;
}