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ovl: add ovl_read_iter() 

Implement stacked reading.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2018-07-18 15:44:41 +02:00
parent 2ef66b8a03
commit 16914e6fc7
1 changed files with 67 additions and 0 deletions
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67
fs/overlayfs/file.c
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@ -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,
};