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ovl: don't copy up opaqueness

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When a copy up of a directory occurs which has the opaque xattr set, the
xattr remains in the upper directory. The immediate behavior with overlayfs
is that the upper directory is not treated as opaque, however after a
remount the opaque flag is used and upper directory is treated as opaque.
This causes files created in the lower layer to be hidden when using
multiple lower directories.

Fix by not copying up the opaque flag.

To reproduce:

 ----8<---------8<---------8<---------8<---------8<---------8<----
mkdir -p l/d/s u v w mnt
mount -t overlay overlay -olowerdir=l,upperdir=u,workdir=w mnt
rm -rf mnt/d/
mkdir -p mnt/d/n
umount mnt
mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt
touch mnt/d/foo
umount mnt
mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt
ls mnt/d
 ----8<---------8<---------8<---------8<---------8<---------8<----
 
output should be:  "foo  n"

Reported-by: Derek McGowan <dmcg@drizz.net>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=151291
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
This commit is contained in:
Miklos Szeredi 2016-08-08 15:08:49 +02:00
parent 29b4817d40
commit 0956254a2d
3 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/overlayfs/copy_up.c
View File

@ -80,6 +80,8 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new)
}
for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
if (ovl_is_private_xattr(name))
continue;
retry:
size = vfs_getxattr(old, name, value, value_size);
if (size == -ERANGE)

2
fs/overlayfs/inode.c
View File

@ -191,7 +191,7 @@ static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
return err;
}
static bool ovl_is_private_xattr(const char *name)
bool ovl_is_private_xattr(const char *name)
{
#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "."
return strncmp(name, OVL_XATTR_PRE_NAME,

1
fs/overlayfs/overlayfs.h
View File

@ -193,6 +193,7 @@ int ovl_removexattr(struct dentry *dentry, const char *name);
struct posix_acl *ovl_get_acl(struct inode *inode, int type);
int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
bool ovl_is_private_xattr(const char *name);
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode);
struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode);