From f9c34674bc60e5fc0af6ec6513517ed9182862b9 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 19 Jan 2018 11:39:52 +0100 Subject: [PATCH] vfs: factor out helpers d_instantiate_anon() and d_alloc_anon() Those helpers are going to be used by overlayfs to implement NFS export decode. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/dcache.c | 87 +++++++++++++++++++++++++++--------------- include/linux/dcache.h | 2 + 2 files changed, 58 insertions(+), 31 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index b5d5ea984ac4..99bce0ed0213 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 +1932,19 @@ 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 +1954,55 @@ 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; + + 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/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 *); -- GitLab