On Fri, Jan 19, 2018 at 02:23:35AM +0200, Amir Goldstein wrote:
> > How is this for an option?
[...]
> > +struct dentry *d_obtain_alias_fsdata(struct inode *inode, void **fsdata)
> > +{
> > + return __d_obtain_alias(inode, 1, fsdata);
> > }
> > EXPORT_SYMBOL(d_obtain_alias);
It would work, but I like this interface better:
+extern struct dentry * d_alloc_anon(struct super_block *);
+extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *);
And full patch:
diff --git a/fs/dcache.c b/fs/dcache.c
index b5d5ea984ac4..15dc32178813 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1699,9 +1699,15 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
}
EXPORT_SYMBOL(d_alloc);
+struct dentry *d_alloc_anon(struct super_block *sb)
+{
+ return __d_alloc(sb, NULL);
+}
+EXPORT_SYMBOL(d_alloc_anon);
+
struct dentry *d_alloc_cursor(struct dentry * parent)
{
- struct dentry *dentry = __d_alloc(parent->d_sb, NULL);
+ struct dentry *dentry = d_alloc_anon(parent->d_sb);
if (dentry) {
dentry->d_flags |= DCACHE_RCUACCESS | DCACHE_DENTRY_CURSOR;
dentry->d_parent = dget(parent);
@@ -1887,7 +1893,7 @@ struct dentry *d_make_root(struct inode *root_inode)
struct dentry *res = NULL;
if (root_inode) {
- res = __d_alloc(root_inode->i_sb, NULL);
+ res = d_alloc_anon(root_inode->i_sb);
if (res)
d_instantiate(res, root_inode);
else
@@ -1926,33 +1932,18 @@ struct dentry *d_find_any_alias(struct inode *inode)
}
EXPORT_SYMBOL(d_find_any_alias);
-static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
+static struct dentry *__d_instantiate_anon(struct dentry *dentry,
+ struct inode *inode,
+ bool disconnected)
{
- struct dentry *tmp;
struct dentry *res;
- unsigned add_flags;
-
- if (!inode)
- return ERR_PTR(-ESTALE);
- if (IS_ERR(inode))
- return ERR_CAST(inode);
-
- res = d_find_any_alias(inode);
- if (res)
- goto out_iput;
- tmp = __d_alloc(inode->i_sb, NULL);
- if (!tmp) {
- res = ERR_PTR(-ENOMEM);
- goto out_iput;
- }
-
- security_d_instantiate(tmp, inode);
+ security_d_instantiate(dentry, inode);
spin_lock(&inode->i_lock);
res = __d_find_any_alias(inode);
if (res) {
spin_unlock(&inode->i_lock);
- dput(tmp);
+ dput(dentry);
goto out_iput;
}
@@ -1962,22 +1953,56 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
if (disconnected)
add_flags |= DCACHE_DISCONNECTED;
- spin_lock(&tmp->d_lock);
- __d_set_inode_and_type(tmp, inode, add_flags);
- hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry);
- hlist_bl_lock(&tmp->d_sb->s_anon);
- hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
- hlist_bl_unlock(&tmp->d_sb->s_anon);
- spin_unlock(&tmp->d_lock);
+ spin_lock(&dentry->d_lock);
+ __d_set_inode_and_type(dentry, inode, add_flags);
+ hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
+ hlist_bl_lock(&dentry->d_sb->s_anon);
+ hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_anon);
+ hlist_bl_unlock(&dentry->d_sb->s_anon);
+ spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
- return tmp;
+ return dentry;
out_iput:
iput(inode);
return res;
}
+struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode)
+{
+ return __d_instantiate_anon(dentry, inode, true);
+}
+EXPORT_SYMBOL(d_instantiate_anon);
+
+static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
+{
+ struct dentry *tmp;
+ struct dentry *res;
+ unsigned add_flags;
+
+ if (!inode)
+ return ERR_PTR(-ESTALE);
+ if (IS_ERR(inode))
+ return ERR_CAST(inode);
+
+ res = d_find_any_alias(inode);
+ if (res)
+ goto out_iput;
+
+ tmp = d_alloc_anon(inode->i_sb);
+ if (!tmp) {
+ res = ERR_PTR(-ENOMEM);
+ goto out_iput;
+ }
+
+ return __d_instantiate_anon(tmp, inode, disconnected);
+
+out_iput:
+ iput(inode);
+ return res;
+}
+
/**
* d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
* @inode: inode to allocate the dentry for
@@ -1998,7 +2023,7 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
*/
struct dentry *d_obtain_alias(struct inode *inode)
{
- return __d_obtain_alias(inode, 1);
+ return __d_obtain_alias(inode, true);
}
EXPORT_SYMBOL(d_obtain_alias);
@@ -2019,7 +2044,7 @@ EXPORT_SYMBOL(d_obtain_alias);
*/
struct dentry *d_obtain_root(struct inode *inode)
{
- return __d_obtain_alias(inode, 0);
+ return __d_obtain_alias(inode, false);
}
EXPORT_SYMBOL(d_obtain_root);
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 25461781c103..7477f28cb99b 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -184,28 +184,32 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
return ERR_CAST(inode);
}
- dentry = d_obtain_alias(inode);
- if (IS_ERR(dentry) || dentry->d_fsdata)
- return dentry;
-
- oe = ovl_alloc_entry(!!lower);
- if (!oe) {
- dput(dentry);
- return ERR_PTR(-ENOMEM);
- }
+ if (index)
+ ovl_set_flag(OVL_INDEX, inode);
- dentry->d_fsdata = oe;
- if (upper_alias)
- ovl_dentry_set_upper_alias(dentry);
- if (lower) {
- oe->lowerstack->dentry = dget(lower);
- oe->lowerstack->layer = lowerpath->layer;
+ dentry = d_find_any_alias(inode);
+ if (!dentry) {
+ dentry = d_alloc_anon(inode->i_sb);
+ if (!dentry)
+ goto nomem;
+ oe = ovl_alloc_entry(lower ? 1 : 0);
+ if (!oe)
+ goto nomem;
+ if (lower) {
+ oe->lowerstack->dentry = dget(lower);
+ oe->lowerstack->layer = lowerpath->layer;
+ }
+ dentry->d_fsdata = oe;
+ if (upper_alias)
+ ovl_dentry_set_upper_alias(dentry);
}
- if (index)
- ovl_set_flag(OVL_INDEX, inode);
+ return d_instantiate_anon(dentry, inode);
- return dentry;
+nomem:
+ iput(inode);
+ dput(dentry);
+ return ERR_PTR(-ENOMEM);
}
/* Get the upper or lower dentry in stach whose on layer @idx */
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 65cd8ab60b7a..82a99d366aec 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -227,6 +227,7 @@ extern seqlock_t rename_lock;
*/
extern void d_instantiate(struct dentry *, struct inode *);
extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
+extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *);
extern int d_instantiate_no_diralias(struct dentry *, struct inode *);
extern void __d_drop(struct dentry *dentry);
extern void d_drop(struct dentry *dentry);
@@ -235,6 +236,7 @@ extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op
/* allocate/de-allocate */
extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
+extern struct dentry * d_alloc_anon(struct super_block *);
extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
wait_queue_head_t *);
--
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