ovl: allow remote upper

No reason to prevent upper layer being a remote filesystem.  Do the
revalidation in that case, just as we already do for lower layers.

This lets virtiofs be used as upper layer, which appears to be a real use
case.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 76e61cc278226ec6d9b76b385b9b1e9c4bb4559c..0db23baf98e7c58dc5d8fff7e8280db65bb7886c 100644 (file)
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -845,8 +845,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
                if (err)
                        goto out;
 
-               if (upperdentry && (upperdentry->d_flags & DCACHE_OP_REAL ||
-                                   unlikely(ovl_dentry_remote(upperdentry)))) {
+               if (upperdentry && upperdentry->d_flags & DCACHE_OP_REAL) {
                        dput(upperdentry);
                        err = -EREMOTE;
                        goto out;

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index d944ab46b69e97944adda45e80ce4eb57ee9d600..e8965fd1a608c716bb0388a874c1a38e7e050f75 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -135,9 +135,14 @@ static int ovl_dentry_revalidate_common(struct dentry *dentry,
                                        unsigned int flags, bool weak)
 {
        struct ovl_entry *oe = dentry->d_fsdata;
+       struct dentry *upper;
        unsigned int i;
        int ret = 1;
 
+       upper = ovl_dentry_upper(dentry);
+       if (upper)
+               ret = ovl_revalidate_real(upper, flags, weak);
+
        for (i = 0; ret > 0 && i < oe->numlower; i++) {
                ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags,
                                          weak);
@@ -747,8 +752,7 @@ static int ovl_mount_dir(const char *name, struct path *path)
                ovl_unescape(tmp);
                err = ovl_mount_dir_noesc(tmp, path);
 
-               if (!err && (ovl_dentry_remote(path->dentry) ||
-                            path->dentry->d_flags & DCACHE_OP_REAL)) {
+               if (!err && path->dentry->d_flags & DCACHE_OP_REAL) {
                        pr_err("filesystem on '%s' not supported as upperdir\n",
                               tmp);
                        path_put_init(path);

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 1cd805ba1eeb5fb2e4f3310b26775ef4364cba39..36b60788ee473f3f4c25df875f81d6efa1d04f59 100644 (file)
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -102,6 +102,8 @@ void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
        struct ovl_entry *oe = OVL_E(dentry);
        unsigned int i, flags = 0;
 
+       if (upperdentry)
+               flags |= upperdentry->d_flags;
        for (i = 0; i < oe->numlower; i++)
                flags |= oe->lowerstack[i].dentry->d_flags;