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vfs: factor out helpers d_instantiate_anon() and d_alloc_anon()

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Those helpers are going to be used by overlayfs to implement
NFS export decode.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2018-01-19 11:39:52 +01:00 committed by Miklos Szeredi
parent c62520a83b
commit f9c34674bc
2 changed files with 60 additions and 33 deletions
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91
fs/dcache.c
View File

@ -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
@ -1926,11 +1932,54 @@ 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 *res;
unsigned add_flags;
security_d_instantiate(dentry, inode);
spin_lock(&inode->i_lock);
res = __d_find_any_alias(inode);
if (res) {
spin_unlock(&inode->i_lock);
dput(dentry);
goto out_iput;
}
/* attach a disconnected dentry */
add_flags = d_flags_for_inode(inode);
if (disconnected)
add_flags |= DCACHE_DISCONNECTED;
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 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);
@ -1941,39 +1990,15 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
if (res)
goto out_iput;
tmp = __d_alloc(inode->i_sb, NULL);
tmp = d_alloc_anon(inode->i_sb);
if (!tmp) {
res = ERR_PTR(-ENOMEM);
goto out_iput;
}
security_d_instantiate(tmp, inode);
spin_lock(&inode->i_lock);
res = __d_find_any_alias(inode);
if (res) {
spin_unlock(&inode->i_lock);
dput(tmp);
goto out_iput;
}
return __d_instantiate_anon(tmp, inode, disconnected);
/* attach a disconnected dentry */
add_flags = d_flags_for_inode(inode);
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_unlock(&inode->i_lock);
return tmp;
out_iput:
out_iput:
iput(inode);
return res;
}
@ -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);

2
include/linux/dcache.h
View File

@ -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 *);