Commit 55acc661 authored by Miklos Szeredi's avatar Miklos Szeredi

ovl: add flag for upper in ovl_entry

For rename, we need to ensure that an upper alias exists for hard links
before attempting the operation.  Introduce a flag in ovl_entry to track
the state of the upper alias.
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 23f0ab13
......@@ -472,6 +472,7 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
if (err)
goto out_cleanup;
ovl_dentry_set_upper_alias(c->dentry);
ovl_inode_update(d_inode(c->dentry), newdentry);
out:
dput(temp);
......
......@@ -156,6 +156,7 @@ static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
{
ovl_dentry_version_inc(dentry->d_parent);
ovl_dentry_set_upper_alias(dentry);
if (!hardlink) {
ovl_inode_update(inode, newdentry);
ovl_copyattr(newdentry->d_inode, inode);
......
......@@ -674,7 +674,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
dentry->d_fsdata = oe;
if (index && !upperdentry)
if (upperdentry)
ovl_dentry_set_upper_alias(dentry);
else if (index)
upperdentry = dget(index);
if (upperdentry || ctr) {
......
......@@ -206,6 +206,8 @@ void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
bool ovl_dentry_has_upper_alias(struct dentry *dentry);
void ovl_dentry_set_upper_alias(struct dentry *dentry);
bool ovl_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
......
......@@ -42,7 +42,10 @@ struct ovl_fs {
/* private information held for every overlayfs dentry */
struct ovl_entry {
union {
struct {
unsigned long has_upper;
bool opaque;
};
struct rcu_head rcu;
};
unsigned numlower;
......
......@@ -1119,6 +1119,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
kfree(lowertmp);
if (upperpath.dentry) {
oe->has_upper = true;
if (ovl_is_impuredir(upperpath.dentry))
ovl_set_flag(OVL_IMPURE, d_inode(root_dentry));
}
......
......@@ -201,6 +201,25 @@ void ovl_dentry_set_opaque(struct dentry *dentry)
oe->opaque = true;
}
/*
* For hard links it's possible for ovl_dentry_upper() to return positive, while
* there's no actual upper alias for the inode. Copy up code needs to know
* about the existence of the upper alias, so it can't use ovl_dentry_upper().
*/
bool ovl_dentry_has_upper_alias(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
return oe->has_upper;
}
void ovl_dentry_set_upper_alias(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
oe->has_upper = true;
}
bool ovl_redirect_dir(struct super_block *sb)
{
struct ovl_fs *ofs = sb->s_fs_info;
......
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