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Commit 16914e6f authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ovl: add ovl_read_iter() 



Implement stacked reading.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 2ef66b8a

fs/overlayfs/file.c

+67 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/cred.h>

#include <linux/file.h>

#include <linux/xattr.h>

#include <linux/uio.h>

#include "overlayfs.h"



static struct file *ovl_open_realfile(const struct file *file)
@@ -129,8 +130,74 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence) 
					i_size_read(realinode));

}



static void ovl_file_accessed(struct file *file)

{

	struct inode *inode, *upperinode;



	if (file->f_flags & O_NOATIME)

		return;



	inode = file_inode(file);

	upperinode = ovl_inode_upper(inode);



	if (!upperinode)

		return;



	if ((!timespec64_equal(&inode->i_mtime, &upperinode->i_mtime) ||

	     !timespec64_equal(&inode->i_ctime, &upperinode->i_ctime))) {

		inode->i_mtime = upperinode->i_mtime;

		inode->i_ctime = upperinode->i_ctime;

	}



	touch_atime(&file->f_path);

}



static rwf_t ovl_iocb_to_rwf(struct kiocb *iocb)

{

	int ifl = iocb->ki_flags;

	rwf_t flags = 0;



	if (ifl & IOCB_NOWAIT)

		flags |= RWF_NOWAIT;

	if (ifl & IOCB_HIPRI)

		flags |= RWF_HIPRI;

	if (ifl & IOCB_DSYNC)

		flags |= RWF_DSYNC;

	if (ifl & IOCB_SYNC)

		flags |= RWF_SYNC;



	return flags;

}



static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)

{

	struct file *file = iocb->ki_filp;

	struct fd real;

	const struct cred *old_cred;

	ssize_t ret;



	if (!iov_iter_count(iter))

		return 0;



	ret = ovl_real_fdget(file, &real);

	if (ret)

		return ret;



	old_cred = ovl_override_creds(file_inode(file)->i_sb);

	ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,

			    ovl_iocb_to_rwf(iocb));

	revert_creds(old_cred);



	ovl_file_accessed(file);



	fdput(real);



	return ret;

}



const struct file_operations ovl_file_operations = {

	.open		= ovl_open,

	.release	= ovl_release,

	.llseek		= ovl_llseek,

	.read_iter	= ovl_read_iter,

};