On Wed, Jan 31, 2018 at 11:13 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> Soon, we will be creating OVL_TYPE_ORIGIN entries even for hardlinked
> files with index=off. That means, it is possible that there is no
> index and hence no OVL_XATTR_NLINK set on upperdentry but lowerdentry
> is still there. In that case current implementation gets -ENODATA
> from vfs_getxattr)() and it warns and returns fallback. I can get
> following warning.
>
> "overlayfs: failed to get index nlink ....."
>
> Pass in index instead of upperdentry in ovl_get_nlink(). That way, if
> index is not there, we know that OVL_XATTR_NLINK should not be
> present and just return fallback.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/overlayfs/inode.c | 13 ++++++-------
> fs/overlayfs/overlayfs.h | 2 +-
> 2 files changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index 00b6b294272a..903548a6b825 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -543,7 +543,7 @@ int ovl_set_nlink_lower(struct dentry *dentry)
> }
>
> unsigned int ovl_get_nlink(struct dentry *lowerdentry,
> - struct dentry *upperdentry,
> + struct dentry *index,
> unsigned int fallback)
> {
> int nlink_diff;
> @@ -551,10 +551,10 @@ unsigned int ovl_get_nlink(struct dentry *lowerdentry,
> char buf[13];
> int err;
>
> - if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1)
> + if (!lowerdentry || !index || d_inode(lowerdentry)->i_nlink == 1)
> return fallback;
>
> - err = vfs_getxattr(upperdentry, OVL_XATTR_NLINK, &buf, sizeof(buf) - 1);
> + err = vfs_getxattr(index, OVL_XATTR_NLINK, &buf, sizeof(buf) - 1);
> if (err < 0)
> goto fail;
>
> @@ -567,7 +567,7 @@ unsigned int ovl_get_nlink(struct dentry *lowerdentry,
> if (err < 0)
> goto fail;
>
> - nlink = d_inode(buf[0] == 'L' ? lowerdentry : upperdentry)->i_nlink;
> + nlink = d_inode(buf[0] == 'L' ? lowerdentry : index)->i_nlink;
> nlink += nlink_diff;
>
> if (nlink <= 0)
> @@ -577,7 +577,7 @@ unsigned int ovl_get_nlink(struct dentry *lowerdentry,
>
> fail:
> pr_warn_ratelimited("overlayfs: failed to get index nlink (%pd2, err=%i)\n",
> - upperdentry, err);
> + index, err);
> return fallback;
> }
>
> @@ -670,8 +670,7 @@ struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry,
> goto out;
> }
>
> - nlink = ovl_get_nlink(lowerdentry, upperdentry,
> - realinode->i_nlink);
> + nlink = ovl_get_nlink(lowerdentry, index, realinode->i_nlink);
> set_nlink(inode, nlink);
> } else {
> inode = new_inode(dentry->d_sb);
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index b489099ccd49..edb23f97bd90 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -274,7 +274,7 @@ int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
> int ovl_set_nlink_upper(struct dentry *dentry);
> int ovl_set_nlink_lower(struct dentry *dentry);
> unsigned int ovl_get_nlink(struct dentry *lowerdentry,
> - struct dentry *upperdentry,
> + struct dentry *index,
> unsigned int fallback);
> int ovl_setattr(struct dentry *dentry, struct iattr *attr);
> int ovl_getattr(const struct path *path, struct kstat *stat,
> --
> 2.13.6
>
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