Re: [PATCH v5] fuse: Add support for passthrough read/write
From: Jann Horn <hidden>
Date: 2016-02-01 19:15:37
Also in:
linux-fsdevel, lkml
On Mon, Feb 01, 2016 at 10:56:27AM -0800, Nikhilesh Reddy wrote:
quoted hunk ↗ jump to hunk
diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c
[...]
+static ssize_t fuse_passthrough_read_write_iter(struct kiocb *iocb,
+ struct iov_iter *iter, int do_write)
+{
+ ssize_t ret_val;
+ struct fuse_file *ff;
+ struct file *fuse_file, *passthrough_filp;
+ struct inode *fuse_inode, *passthrough_inode;
+
+ ff = iocb->ki_filp->private_data;
+ fuse_file = iocb->ki_filp;
+ passthrough_filp = ff->passthrough_filp;
+
+ /* lock passthrough file to prevent it from being released */
+ get_file(passthrough_filp);
+ iocb->ki_filp = passthrough_filp;
+ fuse_inode = fuse_file->f_path.dentry->d_inode;
+ passthrough_inode = file_inode(passthrough_filp);
+
+ if (do_write) {
+ if (!passthrough_filp->f_op->write_iter)
+ return -EIO;
+ ret_val = passthrough_filp->f_op->write_iter(iocb, iter);
+
+ if (ret_val >= 0 || ret_val == -EIOCBQUEUED) {
+ fsstack_copy_inode_size(fuse_inode, passthrough_inode);
+ fsstack_copy_attr_times(fuse_inode, passthrough_inode);
+ }
+ } else {
+ if (!passthrough_filp->f_op->read_iter)
+ return -EIO;
+ ret_val = passthrough_filp->f_op->read_iter(iocb, iter);
+ if (ret_val >= 0 || ret_val == -EIOCBQUEUED)
+ fsstack_copy_attr_atime(fuse_inode, passthrough_inode);
+ }
+
+ iocb->ki_filp = fuse_file;
+
+ /* unlock passthrough file */
+ fput(passthrough_filp);Why the get_file() and fput() in this method? This doesn't look right. There is no lock you're releasing between get_file() and fput(). What are they intended for?
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