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ovl: add splice file read write helper 

[ Upstream commit 1a980b8cbf0059a5308eea61522f232fd03002e2 ]

Now overlayfs falls back to use default file splice read
and write, which is not compatiple with overlayfs, returning
EFAULT. xfstests generic/591 can reproduce part of this.

Tested this patch with xfstests auto group tests.

Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Murphy Zhou 2020-01-17 20:49:29 +08:00 committed by Sasha Levin
parent 85813f1f9e
commit 4f6c9caf7b
1 changed files with 47 additions and 0 deletions
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47
fs/overlayfs/file.c
View File

@ -9,6 +9,9 @@
#include <linux/xattr.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <linux/splice.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include "overlayfs.h"
static char ovl_whatisit(struct inode *inode, struct inode *realinode)
@ -293,6 +296,48 @@ out_unlock:
return ret;
}
static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
ssize_t ret;
struct fd real;
const struct cred *old_cred;
ret = ovl_real_fdget(in, &real);
if (ret)
return ret;
old_cred = ovl_override_creds(file_inode(in)->i_sb);
ret = generic_file_splice_read(real.file, ppos, pipe, len, flags);
revert_creds(old_cred);
ovl_file_accessed(in);
fdput(real);
return ret;
}
static ssize_t
ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
struct fd real;
const struct cred *old_cred;
ssize_t ret;
ret = ovl_real_fdget(out, &real);
if (ret)
return ret;
old_cred = ovl_override_creds(file_inode(out)->i_sb);
ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
revert_creds(old_cred);
ovl_file_accessed(out);
fdput(real);
return ret;
}
static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
struct fd real;
@ -649,6 +694,8 @@ const struct file_operations ovl_file_operations = {
.fadvise = ovl_fadvise,
.unlocked_ioctl = ovl_ioctl,
.compat_ioctl = ovl_compat_ioctl,
.splice_read = ovl_splice_read,
.splice_write = ovl_splice_write,
.copy_file_range = ovl_copy_file_range,
.remap_file_range = ovl_remap_file_range,