/**
* d_find_alias - grab a hashed alias of inode
* @inode: inode in question
- * @want_discon: flag, used by d_splice_alias, to request
- * that only a DISCONNECTED alias be returned.
*
* If inode has a hashed alias, or is a directory and has any alias,
* acquire the reference to alias and return it. Otherwise return NULL.
* of a filesystem.
*
* If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
- * any other hashed alias over that one unless @want_discon is set,
- * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias.
+ * any other hashed alias over that one.
*/
-static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
+static struct dentry *__d_find_alias(struct inode *inode)
{
struct dentry *alias, *discon_alias;
if (IS_ROOT(alias) &&
(alias->d_flags & DCACHE_DISCONNECTED)) {
discon_alias = alias;
- } else if (!want_discon) {
+ } else {
__dget_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
alias = discon_alias;
spin_lock(&alias->d_lock);
if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
- if (IS_ROOT(alias) &&
- (alias->d_flags & DCACHE_DISCONNECTED)) {
- __dget_dlock(alias);
- spin_unlock(&alias->d_lock);
- return alias;
- }
+ __dget_dlock(alias);
+ spin_unlock(&alias->d_lock);
+ return alias;
}
spin_unlock(&alias->d_lock);
goto again;
if (!hlist_empty(&inode->i_dentry)) {
spin_lock(&inode->i_lock);
- de = __d_find_alias(inode, 0);
+ de = __d_find_alias(inode);
spin_unlock(&inode->i_lock);
}
return de;
}
EXPORT_SYMBOL(d_find_any_alias);
-/**
- * d_obtain_alias - find or allocate a dentry for a given inode
- * @inode: inode to allocate the dentry for
- *
- * Obtain a dentry for an inode resulting from NFS filehandle conversion or
- * similar open by handle operations. The returned dentry may be anonymous,
- * or may have a full name (if the inode was already in the cache).
- *
- * When called on a directory inode, we must ensure that the inode only ever
- * has one dentry. If a dentry is found, that is returned instead of
- * allocating a new one.
- *
- * On successful return, the reference to the inode has been transferred
- * to the dentry. In case of an error the reference on the inode is released.
- * To make it easier to use in export operations a %NULL or IS_ERR inode may
- * be passed in and will be the error will be propagate to the return value,
- * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
- */
-struct dentry *d_obtain_alias(struct inode *inode)
+static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
{
static const struct qstr anonstring = QSTR_INIT("/", 1);
struct dentry *tmp;
}
/* attach a disconnected dentry */
- add_flags = d_flags_for_inode(inode) | DCACHE_DISCONNECTED;
+ add_flags = d_flags_for_inode(inode);
+
+ if (disconnected)
+ add_flags |= DCACHE_DISCONNECTED;
spin_lock(&tmp->d_lock);
tmp->d_inode = inode;
iput(inode);
return res;
}
-EXPORT_SYMBOL(d_obtain_alias);
/**
- * d_splice_alias - splice a disconnected dentry into the tree if one exists
- * @inode: the inode which may have a disconnected dentry
- * @dentry: a negative dentry which we want to point to the inode.
- *
- * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and
- * DCACHE_DISCONNECTED), then d_move that in place of the given dentry
- * and return it, else simply d_add the inode to the dentry and return NULL.
+ * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
+ * @inode: inode to allocate the dentry for
*
- * This is needed in the lookup routine of any filesystem that is exportable
- * (via knfsd) so that we can build dcache paths to directories effectively.
+ * Obtain a dentry for an inode resulting from NFS filehandle conversion or
+ * similar open by handle operations. The returned dentry may be anonymous,
+ * or may have a full name (if the inode was already in the cache).
*
- * If a dentry was found and moved, then it is returned. Otherwise NULL
- * is returned. This matches the expected return value of ->lookup.
+ * When called on a directory inode, we must ensure that the inode only ever
+ * has one dentry. If a dentry is found, that is returned instead of
+ * allocating a new one.
*
- * Cluster filesystems may call this function with a negative, hashed dentry.
- * In that case, we know that the inode will be a regular file, and also this
- * will only occur during atomic_open. So we need to check for the dentry
- * being already hashed only in the final case.
+ * On successful return, the reference to the inode has been transferred
+ * to the dentry. In case of an error the reference on the inode is released.
+ * To make it easier to use in export operations a %NULL or IS_ERR inode may
+ * be passed in and the error will be propagated to the return value,
+ * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
*/
-struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
+struct dentry *d_obtain_alias(struct inode *inode)
{
- struct dentry *new = NULL;
-
- if (IS_ERR(inode))
- return ERR_CAST(inode);
+ return __d_obtain_alias(inode, 1);
+}
+EXPORT_SYMBOL(d_obtain_alias);
- if (inode && S_ISDIR(inode->i_mode)) {
- spin_lock(&inode->i_lock);
- new = __d_find_alias(inode, 1);
- if (new) {
- BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
- spin_unlock(&inode->i_lock);
- security_d_instantiate(new, inode);
- d_move(new, dentry);
- iput(inode);
- } else {
- /* already taking inode->i_lock, so d_add() by hand */
- __d_instantiate(dentry, inode);
- spin_unlock(&inode->i_lock);
- security_d_instantiate(dentry, inode);
- d_rehash(dentry);
- }
- } else {
- d_instantiate(dentry, inode);
- if (d_unhashed(dentry))
- d_rehash(dentry);
- }
- return new;
+/**
+ * d_obtain_root - find or allocate a dentry for a given inode
+ * @inode: inode to allocate the dentry for
+ *
+ * Obtain an IS_ROOT dentry for the root of a filesystem.
+ *
+ * We must ensure that directory inodes only ever have one dentry. If a
+ * dentry is found, that is returned instead of allocating a new one.
+ *
+ * On successful return, the reference to the inode has been transferred
+ * to the dentry. In case of an error the reference on the inode is
+ * released. A %NULL or IS_ERR inode may be passed in and will be the
+ * error will be propagate to the return value, with a %NULL @inode
+ * replaced by ERR_PTR(-ESTALE).
+ */
+struct dentry *d_obtain_root(struct inode *inode)
+{
+ return __d_obtain_alias(inode, 0);
}
-EXPORT_SYMBOL(d_splice_alias);
+EXPORT_SYMBOL(d_obtain_root);
/**
* d_add_ci - lookup or allocate new dentry with case-exact name
/* anon->d_lock still locked, returns locked */
}
+/**
+ * d_splice_alias - splice a disconnected dentry into the tree if one exists
+ * @inode: the inode which may have a disconnected dentry
+ * @dentry: a negative dentry which we want to point to the inode.
+ *
+ * If inode is a directory and has an IS_ROOT alias, then d_move that in
+ * place of the given dentry and return it, else simply d_add the inode
+ * to the dentry and return NULL.
+ *
+ * If a non-IS_ROOT directory is found, the filesystem is corrupt, and
+ * we should error out: directories can't have multiple aliases.
+ *
+ * This is needed in the lookup routine of any filesystem that is exportable
+ * (via knfsd) so that we can build dcache paths to directories effectively.
+ *
+ * If a dentry was found and moved, then it is returned. Otherwise NULL
+ * is returned. This matches the expected return value of ->lookup.
+ *
+ * Cluster filesystems may call this function with a negative, hashed dentry.
+ * In that case, we know that the inode will be a regular file, and also this
+ * will only occur during atomic_open. So we need to check for the dentry
+ * being already hashed only in the final case.
+ */
+struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
+{
+ struct dentry *new = NULL;
+
+ if (IS_ERR(inode))
+ return ERR_CAST(inode);
+
+ if (inode && S_ISDIR(inode->i_mode)) {
+ spin_lock(&inode->i_lock);
+ new = __d_find_any_alias(inode);
+ if (new) {
+ if (!IS_ROOT(new)) {
+ spin_unlock(&inode->i_lock);
+ dput(new);
+ return ERR_PTR(-EIO);
+ }
+ if (d_ancestor(new, dentry)) {
+ spin_unlock(&inode->i_lock);
+ dput(new);
+ return ERR_PTR(-EIO);
+ }
+ write_seqlock(&rename_lock);
+ __d_materialise_dentry(dentry, new);
+ write_sequnlock(&rename_lock);
+ __d_drop(new);
+ _d_rehash(new);
+ spin_unlock(&new->d_lock);
+ spin_unlock(&inode->i_lock);
+ security_d_instantiate(new, inode);
+ iput(inode);
+ } else {
+ /* already taking inode->i_lock, so d_add() by hand */
+ __d_instantiate(dentry, inode);
+ spin_unlock(&inode->i_lock);
+ security_d_instantiate(dentry, inode);
+ d_rehash(dentry);
+ }
+ } else {
+ d_instantiate(dentry, inode);
+ if (d_unhashed(dentry))
+ d_rehash(dentry);
+ }
+ return new;
+}
+EXPORT_SYMBOL(d_splice_alias);
+
/**
* d_materialise_unique - introduce an inode into the tree
* @dentry: candidate dentry
struct dentry *alias;
/* Does an aliased dentry already exist? */
- alias = __d_find_alias(inode, 0);
+ alias = __d_find_alias(inode);
if (alias) {
actual = alias;
write_seqlock(&rename_lock);
projects / karo-tx-linux.git / blobdiff