mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

ovl: Open file with data except for the case of fsync 

ovl_open() should open file which contains data and not open metacopy
inode.  With the introduction of metacopy inodes, with current
implementaion we will end up opening metacopy inode as well.

But there can be certain circumstances like ovl_fsync() where we want to
allow opening a metacopy inode instead.

Hence, change ovl_open_realfile() and and add extra parameter which
specifies whether to allow opening metacopy inode or not.  If this
parameter is false, we look for data inode and open that.

This should allow covering both the cases.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Vivek Goyal 2018-05-11 11:49:31 -04:00 committed by Miklos Szeredi
parent 4823d49c26
commit 8c444d2a97
1 changed files with 30 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
fs/overlayfs/file.c
View File

@ -13,11 +13,20 @@
#include <linux/uio.h>
#include "overlayfs.h"
static struct file *ovl_open_realfile(const struct file *file)
static char ovl_whatisit(struct inode *inode, struct inode *realinode)
{
if (realinode != ovl_inode_upper(inode))
return 'l';
if (ovl_has_upperdata(inode))
return 'u';
else
return 'm';
}
static struct file *ovl_open_realfile(const struct file *file,
struct inode *realinode)
{
struct inode *inode = file_inode(file);
struct inode *upperinode = ovl_inode_upper(inode);
struct inode *realinode = upperinode ?: ovl_inode_lower(inode);
struct file *realfile;
const struct cred *old_cred;
@ -27,7 +36,7 @@ static struct file *ovl_open_realfile(const struct file *file)
revert_creds(old_cred);
pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
file, file, upperinode ? 'u' : 'l', file->f_flags,
file, file, ovl_whatisit(inode, realinode), file->f_flags,
realfile, IS_ERR(realfile) ? 0 : realfile->f_flags);
return realfile;
@ -71,17 +80,24 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
return 0;
}
static int ovl_real_fdget(const struct file *file, struct fd *real)
static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
bool allow_meta)
{
struct inode *inode = file_inode(file);
struct inode *realinode;
real->flags = 0;
real->file = file->private_data;
if (allow_meta)
realinode = ovl_inode_real(inode);
else
realinode = ovl_inode_realdata(inode);
/* Has it been copied up since we'd opened it? */
if (unlikely(file_inode(real->file) != ovl_inode_real(inode))) {
if (unlikely(file_inode(real->file) != realinode)) {
real->flags = FDPUT_FPUT;
real->file = ovl_open_realfile(file);
real->file = ovl_open_realfile(file, realinode);
return PTR_ERR_OR_ZERO(real->file);
}
@ -93,6 +109,11 @@ static int ovl_real_fdget(const struct file *file, struct fd *real)
return 0;
}
static int ovl_real_fdget(const struct file *file, struct fd *real)
{
return ovl_real_fdget_meta(file, real, false);
}
static int ovl_open(struct inode *inode, struct file *file)
{
struct dentry *dentry = file_dentry(file);
@ -106,7 +127,7 @@ static int ovl_open(struct inode *inode, struct file *file)
/* No longer need these flags, so don't pass them on to underlying fs */
file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
realfile = ovl_open_realfile(file);
realfile = ovl_open_realfile(file, ovl_inode_realdata(inode));
if (IS_ERR(realfile))
return PTR_ERR(realfile);
@ -243,7 +264,7 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
const struct cred *old_cred;
int ret;
ret = ovl_real_fdget(file, &real);
ret = ovl_real_fdget_meta(file, &real, !datasync);
if (ret)
return ret;