summaryrefslogtreecommitdiffstats
path: root/fs/kernfs/dir.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/kernfs/dir.c')
-rw-r--r--fs/kernfs/dir.c106
1 files changed, 67 insertions, 39 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index f33b3baad07c..935ef8cb02b2 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -125,9 +125,9 @@ static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a,
* kn_to: /n1/n2/n3 [depth=3]
* result: /../..
*
- * [3] when @kn_to is NULL result will be "(null)"
+ * [3] when @kn_to is %NULL result will be "(null)"
*
- * Returns the length of the full path. If the full length is equal to or
+ * Return: the length of the full path. If the full length is equal to or
* greater than @buflen, @buf contains the truncated path with the trailing
* '\0'. On error, -errno is returned.
*/
@@ -185,10 +185,12 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
* @buflen: size of @buf
*
* Copies the name of @kn into @buf of @buflen bytes. The behavior is
- * similar to strlcpy(). It returns the length of @kn's name and if @buf
- * isn't long enough, it's filled upto @buflen-1 and nul terminated.
+ * similar to strlcpy().
*
- * Fills buffer with "(null)" if @kn is NULL.
+ * Fills buffer with "(null)" if @kn is %NULL.
+ *
+ * Return: the length of @kn's name and if @buf isn't long enough,
+ * it's filled up to @buflen-1 and nul terminated.
*
* This function can be called from any context.
*/
@@ -215,7 +217,7 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
* path (which includes '..'s) as needed to reach from @from to @to is
* returned.
*
- * Returns the length of the full path. If the full length is equal to or
+ * Return: the length of the full path. If the full length is equal to or
* greater than @buflen, @buf contains the truncated path with the trailing
* '\0'. On error, -errno is returned.
*/
@@ -287,6 +289,8 @@ out:
*
* Determines @kn's parent, pins and returns it. This function can be
* called from any context.
+ *
+ * Return: parent node of @kn
*/
struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
{
@@ -302,11 +306,11 @@ struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
}
/**
- * kernfs_name_hash
+ * kernfs_name_hash - calculate hash of @ns + @name
* @name: Null terminated string to hash
* @ns: Namespace tag to hash
*
- * Returns 31 bit hash of ns + name (so it fits in an off_t )
+ * Return: 31-bit hash of ns + name (so it fits in an off_t)
*/
static unsigned int kernfs_name_hash(const char *name, const void *ns)
{
@@ -354,8 +358,8 @@ static int kernfs_sd_compare(const struct kernfs_node *left,
* Locking:
* kernfs_rwsem held exclusive
*
- * RETURNS:
- * 0 on susccess -EEXIST on failure.
+ * Return:
+ * %0 on success, -EEXIST on failure.
*/
static int kernfs_link_sibling(struct kernfs_node *kn)
{
@@ -394,8 +398,10 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
* @kn: kernfs_node of interest
*
* Try to unlink @kn from its sibling rbtree which starts from
- * kn->parent->dir.children. Returns %true if @kn was actually
- * removed, %false if @kn wasn't on the rbtree.
+ * kn->parent->dir.children.
+ *
+ * Return: %true if @kn was actually removed,
+ * %false if @kn wasn't on the rbtree.
*
* Locking:
* kernfs_rwsem held exclusive
@@ -419,10 +425,10 @@ static bool kernfs_unlink_sibling(struct kernfs_node *kn)
* @kn: kernfs_node to get an active reference to
*
* Get an active reference of @kn. This function is noop if @kn
- * is NULL.
+ * is %NULL.
*
- * RETURNS:
- * Pointer to @kn on success, NULL on failure.
+ * Return:
+ * Pointer to @kn on success, %NULL on failure.
*/
struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
{
@@ -442,7 +448,7 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
* @kn: kernfs_node to put an active reference to
*
* Put an active reference to @kn. This function is noop if @kn
- * is NULL.
+ * is %NULL.
*/
void kernfs_put_active(struct kernfs_node *kn)
{
@@ -464,7 +470,7 @@ void kernfs_put_active(struct kernfs_node *kn)
* kernfs_drain - drain kernfs_node
* @kn: kernfs_node to drain
*
- * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
+ * Drain existing usages and nuke all existing mmaps of @kn. Multiple
* removers may invoke this function concurrently on @kn and all will
* return after draining is complete.
*/
@@ -577,7 +583,7 @@ EXPORT_SYMBOL_GPL(kernfs_put);
* kernfs_node_from_dentry - determine kernfs_node associated with a dentry
* @dentry: the dentry in question
*
- * Return the kernfs_node associated with @dentry. If @dentry is not a
+ * Return: the kernfs_node associated with @dentry. If @dentry is not a
* kernfs one, %NULL is returned.
*
* While the returned kernfs_node will stay accessible as long as @dentry
@@ -684,8 +690,8 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
* @id's lower 32bits encode ino and upper gen. If the gen portion is
* zero, all generations are matched.
*
- * RETURNS:
- * NULL on failure. Return a kernfs node with reference counter incremented
+ * Return: %NULL on failure,
+ * otherwise a kernfs node with reference counter incremented.
*/
struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
u64 id)
@@ -733,8 +739,8 @@ err_unlock:
* function increments nlink of the parent's inode if @kn is a
* directory and link into the children list of the parent.
*
- * RETURNS:
- * 0 on success, -EEXIST if entry with the given name already
+ * Return:
+ * %0 on success, -EEXIST if entry with the given name already
* exists.
*/
int kernfs_add_one(struct kernfs_node *kn)
@@ -797,8 +803,9 @@ out_unlock:
* @name: name to look for
* @ns: the namespace tag to use
*
- * Look for kernfs_node with name @name under @parent. Returns pointer to
- * the found kernfs_node on success, %NULL on failure.
+ * Look for kernfs_node with name @name under @parent.
+ *
+ * Return: pointer to the found kernfs_node on success, %NULL on failure.
*/
static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
const unsigned char *name,
@@ -871,8 +878,9 @@ static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
* @ns: the namespace tag to use
*
* Look for kernfs_node with name @name under @parent and get a reference
- * if found. This function may sleep and returns pointer to the found
- * kernfs_node on success, %NULL on failure.
+ * if found. This function may sleep.
+ *
+ * Return: pointer to the found kernfs_node on success, %NULL on failure.
*/
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
const char *name, const void *ns)
@@ -896,8 +904,9 @@ EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
* @ns: the namespace tag to use
*
* Look for kernfs_node with path @path under @parent and get a reference
- * if found. This function may sleep and returns pointer to the found
- * kernfs_node on success, %NULL on failure.
+ * if found. This function may sleep.
+ *
+ * Return: pointer to the found kernfs_node on success, %NULL on failure.
*/
struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
const char *path, const void *ns)
@@ -919,7 +928,7 @@ struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
* @flags: KERNFS_ROOT_* flags
* @priv: opaque data associated with the new directory
*
- * Returns the root of the new hierarchy on success, ERR_PTR() value on
+ * Return: the root of the new hierarchy on success, ERR_PTR() value on
* failure.
*/
struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
@@ -991,6 +1000,8 @@ void kernfs_destroy_root(struct kernfs_root *root)
/**
* kernfs_root_to_node - return the kernfs_node associated with a kernfs_root
* @root: root to use to lookup
+ *
+ * Return: @root's kernfs_node
*/
struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root)
{
@@ -1007,7 +1018,7 @@ struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root)
* @priv: opaque data associated with the new directory
* @ns: optional namespace tag of the directory
*
- * Returns the created node on success, ERR_PTR() value on failure.
+ * Return: the created node on success, ERR_PTR() value on failure.
*/
struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
const char *name, umode_t mode,
@@ -1041,7 +1052,7 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
* @parent: parent in which to create a new directory
* @name: name of the new directory
*
- * Returns the created node on success, ERR_PTR() value on failure.
+ * Return: the created node on success, ERR_PTR() value on failure.
*/
struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent,
const char *name)
@@ -1083,20 +1094,30 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
/* If the kernfs parent node has changed discard and
* proceed to ->lookup.
+ *
+ * There's nothing special needed here when getting the
+ * dentry parent, even if a concurrent rename is in
+ * progress. That's because the dentry is negative so
+ * it can only be the target of the rename and it will
+ * be doing a d_move() not a replace. Consequently the
+ * dentry d_parent won't change over the d_move().
+ *
+ * Also kernfs negative dentries transitioning from
+ * negative to positive during revalidate won't happen
+ * because they are invalidated on containing directory
+ * changes and the lookup re-done so that a new positive
+ * dentry can be properly created.
*/
- spin_lock(&dentry->d_lock);
+ root = kernfs_root_from_sb(dentry->d_sb);
+ down_read(&root->kernfs_rwsem);
parent = kernfs_dentry_node(dentry->d_parent);
if (parent) {
- spin_unlock(&dentry->d_lock);
- root = kernfs_root(parent);
- down_read(&root->kernfs_rwsem);
if (kernfs_dir_changed(parent, dentry)) {
up_read(&root->kernfs_rwsem);
return 0;
}
- up_read(&root->kernfs_rwsem);
- } else
- spin_unlock(&dentry->d_lock);
+ }
+ up_read(&root->kernfs_rwsem);
/* The kernfs parent node hasn't changed, leave the
* dentry negative and return success.
@@ -1290,6 +1311,8 @@ static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
* Find the next descendant to visit for post-order traversal of @root's
* descendants. @root is included in the iteration and the last node to be
* visited.
+ *
+ * Return: the next descendant to visit or %NULL when done.
*/
static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
struct kernfs_node *root)
@@ -1553,6 +1576,8 @@ void kernfs_unbreak_active_protection(struct kernfs_node *kn)
* the whole kernfs_ops which won the arbitration. This can be used to
* guarantee, for example, all concurrent writes to a "delete" file to
* finish only after the whole operation is complete.
+ *
+ * Return: %true if @kn is removed by this call, otherwise %false.
*/
bool kernfs_remove_self(struct kernfs_node *kn)
{
@@ -1613,7 +1638,8 @@ bool kernfs_remove_self(struct kernfs_node *kn)
* @ns: namespace tag of the kernfs_node to remove
*
* Look for the kernfs_node with @name and @ns under @parent and remove it.
- * Returns 0 on success, -ENOENT if such entry doesn't exist.
+ *
+ * Return: %0 on success, -ENOENT if such entry doesn't exist.
*/
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
const void *ns)
@@ -1651,6 +1677,8 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
* @new_parent: new parent to put @sd under
* @new_name: new name
* @new_ns: new namespace tag
+ *
+ * Return: %0 on success, -errno on failure.
*/
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
const char *new_name, const void *new_ns)