Make ->d_sb assign-once and always non-NULL
New helper (non-exported, fs/internal.h-only): __d_alloc(sb, name). Allocates dentry, sets its ->d_sb to given superblock and sets ->d_op accordingly. Old d_alloc(NULL, name) callers are converted to that (all of them know what superblock they want). d_alloc() itself is left only for parent != NULl case; uses __d_alloc(), inserts result into the list of parent's children. Note that now ->d_sb is assign-once and never NULL *and* ->d_parent is never NULL either. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
parent
e3c3d9c838
commit
a4464dbc0c
3 changed files with 47 additions and 39 deletions
75
fs/dcache.c
75
fs/dcache.c
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@ -1275,8 +1275,8 @@ static struct shrinker dcache_shrinker = {
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};
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};
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/**
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/**
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* d_alloc - allocate a dcache entry
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* __d_alloc - allocate a dcache entry
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* @parent: parent of entry to allocate
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* @sb: filesystem it will belong to
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* @name: qstr of the name
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* @name: qstr of the name
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*
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*
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* Allocates a dentry. It returns %NULL if there is insufficient memory
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* Allocates a dentry. It returns %NULL if there is insufficient memory
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@ -1284,7 +1284,7 @@ static struct shrinker dcache_shrinker = {
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* copied and the copy passed in may be reused after this call.
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* copied and the copy passed in may be reused after this call.
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*/
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*/
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struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
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struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
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{
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{
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struct dentry *dentry;
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struct dentry *dentry;
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char *dname;
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char *dname;
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@ -1314,8 +1314,8 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
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spin_lock_init(&dentry->d_lock);
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spin_lock_init(&dentry->d_lock);
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seqcount_init(&dentry->d_seq);
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seqcount_init(&dentry->d_seq);
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dentry->d_inode = NULL;
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dentry->d_inode = NULL;
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dentry->d_parent = NULL;
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dentry->d_parent = dentry;
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dentry->d_sb = NULL;
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dentry->d_sb = sb;
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dentry->d_op = NULL;
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dentry->d_op = NULL;
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dentry->d_fsdata = NULL;
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dentry->d_fsdata = NULL;
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INIT_HLIST_BL_NODE(&dentry->d_hash);
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INIT_HLIST_BL_NODE(&dentry->d_hash);
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@ -1323,36 +1323,47 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
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INIT_LIST_HEAD(&dentry->d_subdirs);
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INIT_LIST_HEAD(&dentry->d_subdirs);
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INIT_LIST_HEAD(&dentry->d_alias);
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INIT_LIST_HEAD(&dentry->d_alias);
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INIT_LIST_HEAD(&dentry->d_u.d_child);
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INIT_LIST_HEAD(&dentry->d_u.d_child);
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d_set_d_op(dentry, dentry->d_sb->s_d_op);
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if (parent) {
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spin_lock(&parent->d_lock);
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/*
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* don't need child lock because it is not subject
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* to concurrency here
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*/
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__dget_dlock(parent);
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dentry->d_parent = parent;
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dentry->d_sb = parent->d_sb;
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d_set_d_op(dentry, dentry->d_sb->s_d_op);
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list_add(&dentry->d_u.d_child, &parent->d_subdirs);
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spin_unlock(&parent->d_lock);
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}
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this_cpu_inc(nr_dentry);
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this_cpu_inc(nr_dentry);
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return dentry;
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return dentry;
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}
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}
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/**
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* d_alloc - allocate a dcache entry
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* @parent: parent of entry to allocate
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* @name: qstr of the name
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*
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* Allocates a dentry. It returns %NULL if there is insufficient memory
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* available. On a success the dentry is returned. The name passed in is
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* copied and the copy passed in may be reused after this call.
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*/
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struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
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{
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struct dentry *dentry = __d_alloc(parent->d_sb, name);
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if (!dentry)
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return NULL;
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spin_lock(&parent->d_lock);
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/*
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* don't need child lock because it is not subject
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* to concurrency here
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*/
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__dget_dlock(parent);
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dentry->d_parent = parent;
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list_add(&dentry->d_u.d_child, &parent->d_subdirs);
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spin_unlock(&parent->d_lock);
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return dentry;
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}
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EXPORT_SYMBOL(d_alloc);
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EXPORT_SYMBOL(d_alloc);
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struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
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struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
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{
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{
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struct dentry *dentry = d_alloc(NULL, name);
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struct dentry *dentry = __d_alloc(sb, name);
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if (dentry) {
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if (dentry)
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dentry->d_sb = sb;
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d_set_d_op(dentry, dentry->d_sb->s_d_op);
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dentry->d_parent = dentry;
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dentry->d_flags |= DCACHE_DISCONNECTED;
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dentry->d_flags |= DCACHE_DISCONNECTED;
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}
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return dentry;
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return dentry;
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}
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}
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EXPORT_SYMBOL(d_alloc_pseudo);
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EXPORT_SYMBOL(d_alloc_pseudo);
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@ -1522,13 +1533,9 @@ struct dentry * d_alloc_root(struct inode * root_inode)
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if (root_inode) {
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if (root_inode) {
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static const struct qstr name = { .name = "/", .len = 1 };
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static const struct qstr name = { .name = "/", .len = 1 };
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res = d_alloc(NULL, &name);
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res = __d_alloc(root_inode->i_sb, &name);
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if (res) {
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if (res)
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res->d_sb = root_inode->i_sb;
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d_set_d_op(res, res->d_sb->s_d_op);
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res->d_parent = res;
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d_instantiate(res, root_inode);
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d_instantiate(res, root_inode);
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}
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}
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}
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return res;
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return res;
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}
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}
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@ -1589,13 +1596,11 @@ struct dentry *d_obtain_alias(struct inode *inode)
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if (res)
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if (res)
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goto out_iput;
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goto out_iput;
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tmp = d_alloc(NULL, &anonstring);
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tmp = __d_alloc(inode->i_sb, &anonstring);
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if (!tmp) {
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if (!tmp) {
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res = ERR_PTR(-ENOMEM);
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res = ERR_PTR(-ENOMEM);
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goto out_iput;
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goto out_iput;
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}
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}
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tmp->d_parent = tmp; /* make sure dput doesn't croak */
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spin_lock(&inode->i_lock);
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spin_lock(&inode->i_lock);
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res = __d_find_any_alias(inode);
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res = __d_find_any_alias(inode);
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@ -1607,8 +1612,6 @@ struct dentry *d_obtain_alias(struct inode *inode)
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/* attach a disconnected dentry */
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/* attach a disconnected dentry */
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spin_lock(&tmp->d_lock);
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spin_lock(&tmp->d_lock);
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tmp->d_sb = inode->i_sb;
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d_set_d_op(tmp, tmp->d_sb->s_d_op);
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tmp->d_inode = inode;
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tmp->d_inode = inode;
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tmp->d_flags |= DCACHE_DISCONNECTED;
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tmp->d_flags |= DCACHE_DISCONNECTED;
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list_add(&tmp->d_alias, &inode->i_dentry);
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list_add(&tmp->d_alias, &inode->i_dentry);
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@ -135,3 +135,8 @@ extern void inode_wb_list_del(struct inode *inode);
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extern int get_nr_dirty_inodes(void);
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extern int get_nr_dirty_inodes(void);
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extern void evict_inodes(struct super_block *);
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extern void evict_inodes(struct super_block *);
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extern int invalidate_inodes(struct super_block *, bool);
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extern int invalidate_inodes(struct super_block *, bool);
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/*
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* dcache.c
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*/
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extern struct dentry *__d_alloc(struct super_block *, const struct qstr *);
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@ -16,6 +16,8 @@
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#include <asm/uaccess.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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static inline int simple_positive(struct dentry *dentry)
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static inline int simple_positive(struct dentry *dentry)
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{
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{
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return dentry->d_inode && !d_unhashed(dentry);
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return dentry->d_inode && !d_unhashed(dentry);
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@ -246,13 +248,11 @@ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
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root->i_ino = 1;
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root->i_ino = 1;
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root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
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root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
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root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
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root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
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dentry = d_alloc(NULL, &d_name);
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dentry = __d_alloc(s, &d_name);
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if (!dentry) {
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if (!dentry) {
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iput(root);
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iput(root);
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goto Enomem;
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goto Enomem;
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}
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}
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dentry->d_sb = s;
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dentry->d_parent = dentry;
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d_instantiate(dentry, root);
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d_instantiate(dentry, root);
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s->s_root = dentry;
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s->s_root = dentry;
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s->s_d_op = dops;
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s->s_d_op = dops;
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