1 files changed, 66 insertions, 9 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index e0faf8f2c868..aa03aab6a24f 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1049,6 +1049,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 		tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
 		flush_dcache_page(page);
 
+		iov_iter_advance(ii, tmp);
 		if (!tmp) {
 			unlock_page(page);
 			page_cache_release(page);
@@ -1061,7 +1062,6 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 		req->page_descs[req->num_pages].length = tmp;
 		req->num_pages++;
 
-		iov_iter_advance(ii, tmp);
 		count += tmp;
 		pos += tmp;
 		offset += tmp;
@@ -2231,20 +2231,77 @@ static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
 	return err ? 0 : outarg.block;
 }
 
+static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	struct fuse_file *ff = file->private_data;
+	FUSE_ARGS(args);
+	struct fuse_lseek_in inarg = {
+		.fh = ff->fh,
+		.offset = offset,
+		.whence = whence
+	};
+	struct fuse_lseek_out outarg;
+	int err;
+
+	if (fc->no_lseek)
+		goto fallback;
+
+	args.in.h.opcode = FUSE_LSEEK;
+	args.in.h.nodeid = ff->nodeid;
+	args.in.numargs = 1;
+	args.in.args[0].size = sizeof(inarg);
+	args.in.args[0].value = &inarg;
+	args.out.numargs = 1;
+	args.out.args[0].size = sizeof(outarg);
+	args.out.args[0].value = &outarg;
+	err = fuse_simple_request(fc, &args);
+	if (err) {
+		if (err == -ENOSYS) {
+			fc->no_lseek = 1;
+			goto fallback;
+		}
+		return err;
+	}
+
+	return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
+
+fallback:
+	err = fuse_update_attributes(inode, NULL, file, NULL);
+	if (!err)
+		return generic_file_llseek(file, offset, whence);
+	else
+		return err;
+}
+
 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
 {
 	loff_t retval;
 	struct inode *inode = file_inode(file);
 
-	/* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
-	if (whence == SEEK_CUR || whence == SEEK_SET)
-		return generic_file_llseek(file, offset, whence);
-
-	mutex_lock(&inode->i_mutex);
-	retval = fuse_update_attributes(inode, NULL, file, NULL);
-	if (!retval)
+	switch (whence) {
+	case SEEK_SET:
+	case SEEK_CUR:
+		 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
 		retval = generic_file_llseek(file, offset, whence);
-	mutex_unlock(&inode->i_mutex);
+		break;
+	case SEEK_END:
+		mutex_lock(&inode->i_mutex);
+		retval = fuse_update_attributes(inode, NULL, file, NULL);
+		if (!retval)
+			retval = generic_file_llseek(file, offset, whence);
+		mutex_unlock(&inode->i_mutex);
+		break;
+	case SEEK_HOLE:
+	case SEEK_DATA:
+		mutex_lock(&inode->i_mutex);
+		retval = fuse_lseek(file, offset, whence);
+		mutex_unlock(&inode->i_mutex);
+		break;
+	default:
+		retval = -EINVAL;
+	}
 
 	return retval;
 }