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-rw-r--r--fs/fuse/file.c133
1 files changed, 131 insertions, 2 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 86ffb6db5fe7..6bc3fb26de39 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -363,6 +363,118 @@ static int fuse_commit_write(struct file *file, struct page *page,
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 -ERESTARTSYS;
+
+ 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;
+ } else if (write && (res == -EINTR || res == -EIO))
+ 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)) {
@@ -393,6 +505,17 @@ static struct file_operations fuse_file_operations = {
.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,
@@ -403,6 +526,12 @@ static struct address_space_operations fuse_file_aops = {
void fuse_init_file_inode(struct inode *inode)
{
- inode->i_fop = &fuse_file_operations;
- inode->i_data.a_ops = &fuse_file_aops;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ if (fc->flags & FUSE_DIRECT_IO)
+ inode->i_fop = &fuse_direct_io_file_operations;
+ else {
+ inode->i_fop = &fuse_file_operations;
+ inode->i_data.a_ops = &fuse_file_aops;
+ }
}