|
|
@@ -8,6 +8,7 @@
|
|
|
* This file is released under the GPLv2.
|
|
|
*/
|
|
|
|
|
|
+#include <linux/sched.h>
|
|
|
#include <linux/fs.h>
|
|
|
#include <linux/namei.h>
|
|
|
#include <linux/idr.h>
|
|
|
@@ -18,9 +19,161 @@
|
|
|
#include "kernfs-internal.h"
|
|
|
|
|
|
DEFINE_MUTEX(kernfs_mutex);
|
|
|
+static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */
|
|
|
+static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */
|
|
|
|
|
|
#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
|
|
|
|
|
|
+static bool kernfs_active(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ lockdep_assert_held(&kernfs_mutex);
|
|
|
+ return atomic_read(&kn->active) >= 0;
|
|
|
+}
|
|
|
+
|
|
|
+static bool kernfs_lockdep(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
|
+ return kn->flags & KERNFS_LOCKDEP;
|
|
|
+#else
|
|
|
+ return false;
|
|
|
+#endif
|
|
|
+}
|
|
|
+
|
|
|
+static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
|
|
|
+{
|
|
|
+ return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
|
|
|
+}
|
|
|
+
|
|
|
+static char * __must_check kernfs_path_locked(struct kernfs_node *kn, char *buf,
|
|
|
+ size_t buflen)
|
|
|
+{
|
|
|
+ char *p = buf + buflen;
|
|
|
+ int len;
|
|
|
+
|
|
|
+ *--p = '\0';
|
|
|
+
|
|
|
+ do {
|
|
|
+ len = strlen(kn->name);
|
|
|
+ if (p - buf < len + 1) {
|
|
|
+ buf[0] = '\0';
|
|
|
+ p = NULL;
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ p -= len;
|
|
|
+ memcpy(p, kn->name, len);
|
|
|
+ *--p = '/';
|
|
|
+ kn = kn->parent;
|
|
|
+ } while (kn && kn->parent);
|
|
|
+
|
|
|
+ return p;
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * kernfs_name - obtain the name of a given node
|
|
|
+ * @kn: kernfs_node of interest
|
|
|
+ * @buf: buffer to copy @kn's name into
|
|
|
+ * @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.
|
|
|
+ *
|
|
|
+ * This function can be called from any context.
|
|
|
+ */
|
|
|
+int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
|
|
|
+{
|
|
|
+ unsigned long flags;
|
|
|
+ int ret;
|
|
|
+
|
|
|
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
|
|
|
+ ret = kernfs_name_locked(kn, buf, buflen);
|
|
|
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
|
|
|
+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * kernfs_path - build full path of a given node
|
|
|
+ * @kn: kernfs_node of interest
|
|
|
+ * @buf: buffer to copy @kn's name into
|
|
|
+ * @buflen: size of @buf
|
|
|
+ *
|
|
|
+ * Builds and returns the full path of @kn in @buf of @buflen bytes. The
|
|
|
+ * path is built from the end of @buf so the returned pointer usually
|
|
|
+ * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated
|
|
|
+ * and %NULL is returned.
|
|
|
+ */
|
|
|
+char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
|
|
|
+{
|
|
|
+ unsigned long flags;
|
|
|
+ char *p;
|
|
|
+
|
|
|
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
|
|
|
+ p = kernfs_path_locked(kn, buf, buflen);
|
|
|
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
|
|
|
+ return p;
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * pr_cont_kernfs_name - pr_cont name of a kernfs_node
|
|
|
+ * @kn: kernfs_node of interest
|
|
|
+ *
|
|
|
+ * This function can be called from any context.
|
|
|
+ */
|
|
|
+void pr_cont_kernfs_name(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ unsigned long flags;
|
|
|
+
|
|
|
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
|
|
|
+
|
|
|
+ kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf));
|
|
|
+ pr_cont("%s", kernfs_pr_cont_buf);
|
|
|
+
|
|
|
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * pr_cont_kernfs_path - pr_cont path of a kernfs_node
|
|
|
+ * @kn: kernfs_node of interest
|
|
|
+ *
|
|
|
+ * This function can be called from any context.
|
|
|
+ */
|
|
|
+void pr_cont_kernfs_path(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ unsigned long flags;
|
|
|
+ char *p;
|
|
|
+
|
|
|
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
|
|
|
+
|
|
|
+ p = kernfs_path_locked(kn, kernfs_pr_cont_buf,
|
|
|
+ sizeof(kernfs_pr_cont_buf));
|
|
|
+ if (p)
|
|
|
+ pr_cont("%s", p);
|
|
|
+ else
|
|
|
+ pr_cont("<name too long>");
|
|
|
+
|
|
|
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * kernfs_get_parent - determine the parent node and pin it
|
|
|
+ * @kn: kernfs_node of interest
|
|
|
+ *
|
|
|
+ * Determines @kn's parent, pins and returns it. This function can be
|
|
|
+ * called from any context.
|
|
|
+ */
|
|
|
+struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ struct kernfs_node *parent;
|
|
|
+ unsigned long flags;
|
|
|
+
|
|
|
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
|
|
|
+ parent = kn->parent;
|
|
|
+ kernfs_get(parent);
|
|
|
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
|
|
|
+
|
|
|
+ return parent;
|
|
|
+}
|
|
|
+
|
|
|
/**
|
|
|
* kernfs_name_hash
|
|
|
* @name: Null terminated string to hash
|
|
|
@@ -37,7 +190,7 @@ static unsigned int kernfs_name_hash(const char *name, const void *ns)
|
|
|
hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
|
|
|
hash &= 0x7fffffffU;
|
|
|
/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
|
|
|
- if (hash < 1)
|
|
|
+ if (hash < 2)
|
|
|
hash += 2;
|
|
|
if (hash >= INT_MAX)
|
|
|
hash = INT_MAX - 1;
|
|
|
@@ -105,18 +258,24 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
|
|
|
* kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
|
|
|
* @kn: kernfs_node of interest
|
|
|
*
|
|
|
- * Unlink @kn from its sibling rbtree which starts from
|
|
|
- * kn->parent->dir.children.
|
|
|
+ * 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.
|
|
|
*
|
|
|
* Locking:
|
|
|
* mutex_lock(kernfs_mutex)
|
|
|
*/
|
|
|
-static void kernfs_unlink_sibling(struct kernfs_node *kn)
|
|
|
+static bool kernfs_unlink_sibling(struct kernfs_node *kn)
|
|
|
{
|
|
|
+ if (RB_EMPTY_NODE(&kn->rb))
|
|
|
+ return false;
|
|
|
+
|
|
|
if (kernfs_type(kn) == KERNFS_DIR)
|
|
|
kn->parent->dir.subdirs--;
|
|
|
|
|
|
rb_erase(&kn->rb, &kn->parent->dir.children);
|
|
|
+ RB_CLEAR_NODE(&kn->rb);
|
|
|
+ return true;
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
@@ -137,7 +296,7 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
|
|
|
if (!atomic_inc_unless_negative(&kn->active))
|
|
|
return NULL;
|
|
|
|
|
|
- if (kn->flags & KERNFS_LOCKDEP)
|
|
|
+ if (kernfs_lockdep(kn))
|
|
|
rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
|
|
|
return kn;
|
|
|
}
|
|
|
@@ -151,59 +310,57 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
|
|
|
*/
|
|
|
void kernfs_put_active(struct kernfs_node *kn)
|
|
|
{
|
|
|
+ struct kernfs_root *root = kernfs_root(kn);
|
|
|
int v;
|
|
|
|
|
|
if (unlikely(!kn))
|
|
|
return;
|
|
|
|
|
|
- if (kn->flags & KERNFS_LOCKDEP)
|
|
|
+ if (kernfs_lockdep(kn))
|
|
|
rwsem_release(&kn->dep_map, 1, _RET_IP_);
|
|
|
v = atomic_dec_return(&kn->active);
|
|
|
if (likely(v != KN_DEACTIVATED_BIAS))
|
|
|
return;
|
|
|
|
|
|
- /*
|
|
|
- * atomic_dec_return() is a mb(), we'll always see the updated
|
|
|
- * kn->u.completion.
|
|
|
- */
|
|
|
- complete(kn->u.completion);
|
|
|
+ wake_up_all(&root->deactivate_waitq);
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
- * kernfs_deactivate - deactivate kernfs_node
|
|
|
- * @kn: kernfs_node to deactivate
|
|
|
+ * kernfs_drain - drain kernfs_node
|
|
|
+ * @kn: kernfs_node to drain
|
|
|
*
|
|
|
- * Deny new active references and drain existing ones.
|
|
|
+ * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
|
|
|
+ * removers may invoke this function concurrently on @kn and all will
|
|
|
+ * return after draining is complete.
|
|
|
*/
|
|
|
-static void kernfs_deactivate(struct kernfs_node *kn)
|
|
|
+static void kernfs_drain(struct kernfs_node *kn)
|
|
|
+ __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
|
|
|
{
|
|
|
- DECLARE_COMPLETION_ONSTACK(wait);
|
|
|
- int v;
|
|
|
+ struct kernfs_root *root = kernfs_root(kn);
|
|
|
|
|
|
- BUG_ON(!(kn->flags & KERNFS_REMOVED));
|
|
|
-
|
|
|
- if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF))
|
|
|
- return;
|
|
|
+ lockdep_assert_held(&kernfs_mutex);
|
|
|
+ WARN_ON_ONCE(kernfs_active(kn));
|
|
|
|
|
|
- kn->u.completion = (void *)&wait;
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
|
|
|
- if (kn->flags & KERNFS_LOCKDEP)
|
|
|
+ if (kernfs_lockdep(kn)) {
|
|
|
rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
|
|
|
- /* atomic_add_return() is a mb(), put_active() will always see
|
|
|
- * the updated kn->u.completion.
|
|
|
- */
|
|
|
- v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active);
|
|
|
-
|
|
|
- if (v != KN_DEACTIVATED_BIAS) {
|
|
|
- if (kn->flags & KERNFS_LOCKDEP)
|
|
|
+ if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
|
|
|
lock_contended(&kn->dep_map, _RET_IP_);
|
|
|
- wait_for_completion(&wait);
|
|
|
}
|
|
|
|
|
|
- if (kn->flags & KERNFS_LOCKDEP) {
|
|
|
+ /* but everyone should wait for draining */
|
|
|
+ wait_event(root->deactivate_waitq,
|
|
|
+ atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
|
|
|
+
|
|
|
+ if (kernfs_lockdep(kn)) {
|
|
|
lock_acquired(&kn->dep_map, _RET_IP_);
|
|
|
rwsem_release(&kn->dep_map, 1, _RET_IP_);
|
|
|
}
|
|
|
+
|
|
|
+ kernfs_unmap_bin_file(kn);
|
|
|
+
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
@@ -234,13 +391,15 @@ void kernfs_put(struct kernfs_node *kn)
|
|
|
return;
|
|
|
root = kernfs_root(kn);
|
|
|
repeat:
|
|
|
- /* Moving/renaming is always done while holding reference.
|
|
|
+ /*
|
|
|
+ * Moving/renaming is always done while holding reference.
|
|
|
* kn->parent won't change beneath us.
|
|
|
*/
|
|
|
parent = kn->parent;
|
|
|
|
|
|
- WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
|
|
|
- parent ? parent->name : "", kn->name);
|
|
|
+ WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
|
|
|
+ "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
|
|
|
+ parent ? parent->name : "", kn->name, atomic_read(&kn->active));
|
|
|
|
|
|
if (kernfs_type(kn) == KERNFS_LINK)
|
|
|
kernfs_put(kn->symlink.target_kn);
|
|
|
@@ -282,8 +441,8 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
|
|
|
kn = dentry->d_fsdata;
|
|
|
mutex_lock(&kernfs_mutex);
|
|
|
|
|
|
- /* The kernfs node has been deleted */
|
|
|
- if (kn->flags & KERNFS_REMOVED)
|
|
|
+ /* The kernfs node has been deactivated */
|
|
|
+ if (!kernfs_active(kn))
|
|
|
goto out_bad;
|
|
|
|
|
|
/* The kernfs node has been moved? */
|
|
|
@@ -328,6 +487,24 @@ const struct dentry_operations kernfs_dops = {
|
|
|
.d_release = kernfs_dop_release,
|
|
|
};
|
|
|
|
|
|
+/**
|
|
|
+ * 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
|
|
|
+ * kernfs one, %NULL is returned.
|
|
|
+ *
|
|
|
+ * While the returned kernfs_node will stay accessible as long as @dentry
|
|
|
+ * is accessible, the returned node can be in any state and the caller is
|
|
|
+ * fully responsible for determining what's accessible.
|
|
|
+ */
|
|
|
+struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
|
|
|
+{
|
|
|
+ if (dentry->d_sb->s_op == &kernfs_sops)
|
|
|
+ return dentry->d_fsdata;
|
|
|
+ return NULL;
|
|
|
+}
|
|
|
+
|
|
|
static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
|
|
|
const char *name, umode_t mode,
|
|
|
unsigned flags)
|
|
|
@@ -352,11 +529,12 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
|
|
|
kn->ino = ret;
|
|
|
|
|
|
atomic_set(&kn->count, 1);
|
|
|
- atomic_set(&kn->active, 0);
|
|
|
+ atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
|
|
|
+ RB_CLEAR_NODE(&kn->rb);
|
|
|
|
|
|
kn->name = name;
|
|
|
kn->mode = mode;
|
|
|
- kn->flags = flags | KERNFS_REMOVED;
|
|
|
+ kn->flags = flags;
|
|
|
|
|
|
return kn;
|
|
|
|
|
|
@@ -381,70 +559,45 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
|
|
|
return kn;
|
|
|
}
|
|
|
|
|
|
-/**
|
|
|
- * kernfs_addrm_start - prepare for kernfs_node add/remove
|
|
|
- * @acxt: pointer to kernfs_addrm_cxt to be used
|
|
|
- *
|
|
|
- * This function is called when the caller is about to add or remove
|
|
|
- * kernfs_node. This function acquires kernfs_mutex. @acxt is used
|
|
|
- * to keep and pass context to other addrm functions.
|
|
|
- *
|
|
|
- * LOCKING:
|
|
|
- * Kernel thread context (may sleep). kernfs_mutex is locked on
|
|
|
- * return.
|
|
|
- */
|
|
|
-void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
|
|
|
- __acquires(kernfs_mutex)
|
|
|
-{
|
|
|
- memset(acxt, 0, sizeof(*acxt));
|
|
|
-
|
|
|
- mutex_lock(&kernfs_mutex);
|
|
|
-}
|
|
|
-
|
|
|
/**
|
|
|
* kernfs_add_one - add kernfs_node to parent without warning
|
|
|
- * @acxt: addrm context to use
|
|
|
* @kn: kernfs_node to be added
|
|
|
*
|
|
|
* The caller must already have initialized @kn->parent. This
|
|
|
* function increments nlink of the parent's inode if @kn is a
|
|
|
* directory and link into the children list of the parent.
|
|
|
*
|
|
|
- * This function should be called between calls to
|
|
|
- * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
|
|
|
- * the same @acxt as passed to kernfs_addrm_start().
|
|
|
- *
|
|
|
- * LOCKING:
|
|
|
- * Determined by kernfs_addrm_start().
|
|
|
- *
|
|
|
* RETURNS:
|
|
|
* 0 on success, -EEXIST if entry with the given name already
|
|
|
* exists.
|
|
|
*/
|
|
|
-int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
|
|
|
+int kernfs_add_one(struct kernfs_node *kn)
|
|
|
{
|
|
|
struct kernfs_node *parent = kn->parent;
|
|
|
- bool has_ns = kernfs_ns_enabled(parent);
|
|
|
struct kernfs_iattrs *ps_iattr;
|
|
|
+ bool has_ns;
|
|
|
int ret;
|
|
|
|
|
|
- if (has_ns != (bool)kn->ns) {
|
|
|
- WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
|
|
|
- has_ns ? "required" : "invalid", parent->name, kn->name);
|
|
|
- return -EINVAL;
|
|
|
- }
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
+
|
|
|
+ ret = -EINVAL;
|
|
|
+ has_ns = kernfs_ns_enabled(parent);
|
|
|
+ if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
|
|
|
+ has_ns ? "required" : "invalid", parent->name, kn->name))
|
|
|
+ goto out_unlock;
|
|
|
|
|
|
if (kernfs_type(parent) != KERNFS_DIR)
|
|
|
- return -EINVAL;
|
|
|
+ goto out_unlock;
|
|
|
|
|
|
- if (parent->flags & KERNFS_REMOVED)
|
|
|
- return -ENOENT;
|
|
|
+ ret = -ENOENT;
|
|
|
+ if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent))
|
|
|
+ goto out_unlock;
|
|
|
|
|
|
kn->hash = kernfs_name_hash(kn->name, kn->ns);
|
|
|
|
|
|
ret = kernfs_link_sibling(kn);
|
|
|
if (ret)
|
|
|
- return ret;
|
|
|
+ goto out_unlock;
|
|
|
|
|
|
/* Update timestamps on the parent */
|
|
|
ps_iattr = parent->iattr;
|
|
|
@@ -453,82 +606,22 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
|
|
|
ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
|
|
|
}
|
|
|
|
|
|
- /* Mark the entry added into directory tree */
|
|
|
- kn->flags &= ~KERNFS_REMOVED;
|
|
|
-
|
|
|
- return 0;
|
|
|
-}
|
|
|
-
|
|
|
-/**
|
|
|
- * kernfs_remove_one - remove kernfs_node from parent
|
|
|
- * @acxt: addrm context to use
|
|
|
- * @kn: kernfs_node to be removed
|
|
|
- *
|
|
|
- * Mark @kn removed and drop nlink of parent inode if @kn is a
|
|
|
- * directory. @kn is unlinked from the children list.
|
|
|
- *
|
|
|
- * This function should be called between calls to
|
|
|
- * kernfs_addrm_start() and kernfs_addrm_finish() and should be
|
|
|
- * passed the same @acxt as passed to kernfs_addrm_start().
|
|
|
- *
|
|
|
- * LOCKING:
|
|
|
- * Determined by kernfs_addrm_start().
|
|
|
- */
|
|
|
-static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
|
|
|
- struct kernfs_node *kn)
|
|
|
-{
|
|
|
- struct kernfs_iattrs *ps_iattr;
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
|
|
|
/*
|
|
|
- * Removal can be called multiple times on the same node. Only the
|
|
|
- * first invocation is effective and puts the base ref.
|
|
|
+ * Activate the new node unless CREATE_DEACTIVATED is requested.
|
|
|
+ * If not activated here, the kernfs user is responsible for
|
|
|
+ * activating the node with kernfs_activate(). A node which hasn't
|
|
|
+ * been activated is not visible to userland and its removal won't
|
|
|
+ * trigger deactivation.
|
|
|
*/
|
|
|
- if (kn->flags & KERNFS_REMOVED)
|
|
|
- return;
|
|
|
-
|
|
|
- if (kn->parent) {
|
|
|
- kernfs_unlink_sibling(kn);
|
|
|
-
|
|
|
- /* Update timestamps on the parent */
|
|
|
- ps_iattr = kn->parent->iattr;
|
|
|
- if (ps_iattr) {
|
|
|
- ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
|
|
|
- ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
|
|
|
- }
|
|
|
- }
|
|
|
-
|
|
|
- kn->flags |= KERNFS_REMOVED;
|
|
|
- kn->u.removed_list = acxt->removed;
|
|
|
- acxt->removed = kn;
|
|
|
-}
|
|
|
+ if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
|
|
|
+ kernfs_activate(kn);
|
|
|
+ return 0;
|
|
|
|
|
|
-/**
|
|
|
- * kernfs_addrm_finish - finish up kernfs_node add/remove
|
|
|
- * @acxt: addrm context to finish up
|
|
|
- *
|
|
|
- * Finish up kernfs_node add/remove. Resources acquired by
|
|
|
- * kernfs_addrm_start() are released and removed kernfs_nodes are
|
|
|
- * cleaned up.
|
|
|
- *
|
|
|
- * LOCKING:
|
|
|
- * kernfs_mutex is released.
|
|
|
- */
|
|
|
-void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
|
|
|
- __releases(kernfs_mutex)
|
|
|
-{
|
|
|
- /* release resources acquired by kernfs_addrm_start() */
|
|
|
+out_unlock:
|
|
|
mutex_unlock(&kernfs_mutex);
|
|
|
-
|
|
|
- /* kill removed kernfs_nodes */
|
|
|
- while (acxt->removed) {
|
|
|
- struct kernfs_node *kn = acxt->removed;
|
|
|
-
|
|
|
- acxt->removed = kn->u.removed_list;
|
|
|
-
|
|
|
- kernfs_deactivate(kn);
|
|
|
- kernfs_unmap_bin_file(kn);
|
|
|
- kernfs_put(kn);
|
|
|
- }
|
|
|
+ return ret;
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
@@ -599,13 +692,15 @@ EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
|
|
|
|
|
|
/**
|
|
|
* kernfs_create_root - create a new kernfs hierarchy
|
|
|
- * @kdops: optional directory syscall operations for the hierarchy
|
|
|
+ * @scops: optional syscall operations for the hierarchy
|
|
|
+ * @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
|
|
|
* failure.
|
|
|
*/
|
|
|
-struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
|
|
|
+struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
|
|
|
+ unsigned int flags, void *priv)
|
|
|
{
|
|
|
struct kernfs_root *root;
|
|
|
struct kernfs_node *kn;
|
|
|
@@ -624,12 +719,16 @@ struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
|
|
|
return ERR_PTR(-ENOMEM);
|
|
|
}
|
|
|
|
|
|
- kn->flags &= ~KERNFS_REMOVED;
|
|
|
kn->priv = priv;
|
|
|
kn->dir.root = root;
|
|
|
|
|
|
- root->dir_ops = kdops;
|
|
|
+ root->syscall_ops = scops;
|
|
|
+ root->flags = flags;
|
|
|
root->kn = kn;
|
|
|
+ init_waitqueue_head(&root->deactivate_waitq);
|
|
|
+
|
|
|
+ if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
|
|
|
+ kernfs_activate(kn);
|
|
|
|
|
|
return root;
|
|
|
}
|
|
|
@@ -660,7 +759,6 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
|
|
|
const char *name, umode_t mode,
|
|
|
void *priv, const void *ns)
|
|
|
{
|
|
|
- struct kernfs_addrm_cxt acxt;
|
|
|
struct kernfs_node *kn;
|
|
|
int rc;
|
|
|
|
|
|
@@ -674,10 +772,7 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
|
|
|
kn->priv = priv;
|
|
|
|
|
|
/* link in */
|
|
|
- kernfs_addrm_start(&acxt);
|
|
|
- rc = kernfs_add_one(&acxt, kn);
|
|
|
- kernfs_addrm_finish(&acxt);
|
|
|
-
|
|
|
+ rc = kernfs_add_one(kn);
|
|
|
if (!rc)
|
|
|
return kn;
|
|
|
|
|
|
@@ -703,7 +798,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
|
|
|
kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
|
|
|
|
|
|
/* no such entry */
|
|
|
- if (!kn) {
|
|
|
+ if (!kn || !kernfs_active(kn)) {
|
|
|
ret = NULL;
|
|
|
goto out_unlock;
|
|
|
}
|
|
|
@@ -728,23 +823,37 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
|
|
|
umode_t mode)
|
|
|
{
|
|
|
struct kernfs_node *parent = dir->i_private;
|
|
|
- struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
|
|
|
+ struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops;
|
|
|
+ int ret;
|
|
|
|
|
|
- if (!kdops || !kdops->mkdir)
|
|
|
+ if (!scops || !scops->mkdir)
|
|
|
return -EPERM;
|
|
|
|
|
|
- return kdops->mkdir(parent, dentry->d_name.name, mode);
|
|
|
+ if (!kernfs_get_active(parent))
|
|
|
+ return -ENODEV;
|
|
|
+
|
|
|
+ ret = scops->mkdir(parent, dentry->d_name.name, mode);
|
|
|
+
|
|
|
+ kernfs_put_active(parent);
|
|
|
+ return ret;
|
|
|
}
|
|
|
|
|
|
static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
|
|
|
{
|
|
|
struct kernfs_node *kn = dentry->d_fsdata;
|
|
|
- struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
|
|
|
+ struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
|
|
|
+ int ret;
|
|
|
|
|
|
- if (!kdops || !kdops->rmdir)
|
|
|
+ if (!scops || !scops->rmdir)
|
|
|
return -EPERM;
|
|
|
|
|
|
- return kdops->rmdir(kn);
|
|
|
+ if (!kernfs_get_active(kn))
|
|
|
+ return -ENODEV;
|
|
|
+
|
|
|
+ ret = scops->rmdir(kn);
|
|
|
+
|
|
|
+ kernfs_put_active(kn);
|
|
|
+ return ret;
|
|
|
}
|
|
|
|
|
|
static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
|
|
|
@@ -752,12 +861,25 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
|
|
|
{
|
|
|
struct kernfs_node *kn = old_dentry->d_fsdata;
|
|
|
struct kernfs_node *new_parent = new_dir->i_private;
|
|
|
- struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
|
|
|
+ struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
|
|
|
+ int ret;
|
|
|
|
|
|
- if (!kdops || !kdops->rename)
|
|
|
+ if (!scops || !scops->rename)
|
|
|
return -EPERM;
|
|
|
|
|
|
- return kdops->rename(kn, new_parent, new_dentry->d_name.name);
|
|
|
+ if (!kernfs_get_active(kn))
|
|
|
+ return -ENODEV;
|
|
|
+
|
|
|
+ if (!kernfs_get_active(new_parent)) {
|
|
|
+ kernfs_put_active(kn);
|
|
|
+ return -ENODEV;
|
|
|
+ }
|
|
|
+
|
|
|
+ ret = scops->rename(kn, new_parent, new_dentry->d_name.name);
|
|
|
+
|
|
|
+ kernfs_put_active(new_parent);
|
|
|
+ kernfs_put_active(kn);
|
|
|
+ return ret;
|
|
|
}
|
|
|
|
|
|
const struct inode_operations kernfs_dir_iops = {
|
|
|
@@ -830,23 +952,104 @@ static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
|
|
|
return pos->parent;
|
|
|
}
|
|
|
|
|
|
-static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
|
|
|
- struct kernfs_node *kn)
|
|
|
+/**
|
|
|
+ * kernfs_activate - activate a node which started deactivated
|
|
|
+ * @kn: kernfs_node whose subtree is to be activated
|
|
|
+ *
|
|
|
+ * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node
|
|
|
+ * needs to be explicitly activated. A node which hasn't been activated
|
|
|
+ * isn't visible to userland and deactivation is skipped during its
|
|
|
+ * removal. This is useful to construct atomic init sequences where
|
|
|
+ * creation of multiple nodes should either succeed or fail atomically.
|
|
|
+ *
|
|
|
+ * The caller is responsible for ensuring that this function is not called
|
|
|
+ * after kernfs_remove*() is invoked on @kn.
|
|
|
+ */
|
|
|
+void kernfs_activate(struct kernfs_node *kn)
|
|
|
{
|
|
|
- struct kernfs_node *pos, *next;
|
|
|
+ struct kernfs_node *pos;
|
|
|
|
|
|
- if (!kn)
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
+
|
|
|
+ pos = NULL;
|
|
|
+ while ((pos = kernfs_next_descendant_post(pos, kn))) {
|
|
|
+ if (!pos || (pos->flags & KERNFS_ACTIVATED))
|
|
|
+ continue;
|
|
|
+
|
|
|
+ WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb));
|
|
|
+ WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS);
|
|
|
+
|
|
|
+ atomic_sub(KN_DEACTIVATED_BIAS, &pos->active);
|
|
|
+ pos->flags |= KERNFS_ACTIVATED;
|
|
|
+ }
|
|
|
+
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
+}
|
|
|
+
|
|
|
+static void __kernfs_remove(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ struct kernfs_node *pos;
|
|
|
+
|
|
|
+ lockdep_assert_held(&kernfs_mutex);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * Short-circuit if non-root @kn has already finished removal.
|
|
|
+ * This is for kernfs_remove_self() which plays with active ref
|
|
|
+ * after removal.
|
|
|
+ */
|
|
|
+ if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb)))
|
|
|
return;
|
|
|
|
|
|
pr_debug("kernfs %s: removing\n", kn->name);
|
|
|
|
|
|
- next = NULL;
|
|
|
+ /* prevent any new usage under @kn by deactivating all nodes */
|
|
|
+ pos = NULL;
|
|
|
+ while ((pos = kernfs_next_descendant_post(pos, kn)))
|
|
|
+ if (kernfs_active(pos))
|
|
|
+ atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
|
|
|
+
|
|
|
+ /* deactivate and unlink the subtree node-by-node */
|
|
|
do {
|
|
|
- pos = next;
|
|
|
- next = kernfs_next_descendant_post(pos, kn);
|
|
|
- if (pos)
|
|
|
- kernfs_remove_one(acxt, pos);
|
|
|
- } while (next);
|
|
|
+ pos = kernfs_leftmost_descendant(kn);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * kernfs_drain() drops kernfs_mutex temporarily and @pos's
|
|
|
+ * base ref could have been put by someone else by the time
|
|
|
+ * the function returns. Make sure it doesn't go away
|
|
|
+ * underneath us.
|
|
|
+ */
|
|
|
+ kernfs_get(pos);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * Drain iff @kn was activated. This avoids draining and
|
|
|
+ * its lockdep annotations for nodes which have never been
|
|
|
+ * activated and allows embedding kernfs_remove() in create
|
|
|
+ * error paths without worrying about draining.
|
|
|
+ */
|
|
|
+ if (kn->flags & KERNFS_ACTIVATED)
|
|
|
+ kernfs_drain(pos);
|
|
|
+ else
|
|
|
+ WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * kernfs_unlink_sibling() succeeds once per node. Use it
|
|
|
+ * to decide who's responsible for cleanups.
|
|
|
+ */
|
|
|
+ if (!pos->parent || kernfs_unlink_sibling(pos)) {
|
|
|
+ struct kernfs_iattrs *ps_iattr =
|
|
|
+ pos->parent ? pos->parent->iattr : NULL;
|
|
|
+
|
|
|
+ /* update timestamps on the parent */
|
|
|
+ if (ps_iattr) {
|
|
|
+ ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
|
|
|
+ ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
|
|
|
+ }
|
|
|
+
|
|
|
+ kernfs_put(pos);
|
|
|
+ }
|
|
|
+
|
|
|
+ kernfs_put(pos);
|
|
|
+ } while (pos != kn);
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
@@ -857,11 +1060,140 @@ static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
|
|
|
*/
|
|
|
void kernfs_remove(struct kernfs_node *kn)
|
|
|
{
|
|
|
- struct kernfs_addrm_cxt acxt;
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
+ __kernfs_remove(kn);
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
+}
|
|
|
|
|
|
- kernfs_addrm_start(&acxt);
|
|
|
- __kernfs_remove(&acxt, kn);
|
|
|
- kernfs_addrm_finish(&acxt);
|
|
|
+/**
|
|
|
+ * kernfs_break_active_protection - break out of active protection
|
|
|
+ * @kn: the self kernfs_node
|
|
|
+ *
|
|
|
+ * The caller must be running off of a kernfs operation which is invoked
|
|
|
+ * with an active reference - e.g. one of kernfs_ops. Each invocation of
|
|
|
+ * this function must also be matched with an invocation of
|
|
|
+ * kernfs_unbreak_active_protection().
|
|
|
+ *
|
|
|
+ * This function releases the active reference of @kn the caller is
|
|
|
+ * holding. Once this function is called, @kn may be removed at any point
|
|
|
+ * and the caller is solely responsible for ensuring that the objects it
|
|
|
+ * dereferences are accessible.
|
|
|
+ */
|
|
|
+void kernfs_break_active_protection(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ /*
|
|
|
+ * Take out ourself out of the active ref dependency chain. If
|
|
|
+ * we're called without an active ref, lockdep will complain.
|
|
|
+ */
|
|
|
+ kernfs_put_active(kn);
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * kernfs_unbreak_active_protection - undo kernfs_break_active_protection()
|
|
|
+ * @kn: the self kernfs_node
|
|
|
+ *
|
|
|
+ * If kernfs_break_active_protection() was called, this function must be
|
|
|
+ * invoked before finishing the kernfs operation. Note that while this
|
|
|
+ * function restores the active reference, it doesn't and can't actually
|
|
|
+ * restore the active protection - @kn may already or be in the process of
|
|
|
+ * being removed. Once kernfs_break_active_protection() is invoked, that
|
|
|
+ * protection is irreversibly gone for the kernfs operation instance.
|
|
|
+ *
|
|
|
+ * While this function may be called at any point after
|
|
|
+ * kernfs_break_active_protection() is invoked, its most useful location
|
|
|
+ * would be right before the enclosing kernfs operation returns.
|
|
|
+ */
|
|
|
+void kernfs_unbreak_active_protection(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ /*
|
|
|
+ * @kn->active could be in any state; however, the increment we do
|
|
|
+ * here will be undone as soon as the enclosing kernfs operation
|
|
|
+ * finishes and this temporary bump can't break anything. If @kn
|
|
|
+ * is alive, nothing changes. If @kn is being deactivated, the
|
|
|
+ * soon-to-follow put will either finish deactivation or restore
|
|
|
+ * deactivated state. If @kn is already removed, the temporary
|
|
|
+ * bump is guaranteed to be gone before @kn is released.
|
|
|
+ */
|
|
|
+ atomic_inc(&kn->active);
|
|
|
+ if (kernfs_lockdep(kn))
|
|
|
+ rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_);
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * kernfs_remove_self - remove a kernfs_node from its own method
|
|
|
+ * @kn: the self kernfs_node to remove
|
|
|
+ *
|
|
|
+ * The caller must be running off of a kernfs operation which is invoked
|
|
|
+ * with an active reference - e.g. one of kernfs_ops. This can be used to
|
|
|
+ * implement a file operation which deletes itself.
|
|
|
+ *
|
|
|
+ * For example, the "delete" file for a sysfs device directory can be
|
|
|
+ * implemented by invoking kernfs_remove_self() on the "delete" file
|
|
|
+ * itself. This function breaks the circular dependency of trying to
|
|
|
+ * deactivate self while holding an active ref itself. It isn't necessary
|
|
|
+ * to modify the usual removal path to use kernfs_remove_self(). The
|
|
|
+ * "delete" implementation can simply invoke kernfs_remove_self() on self
|
|
|
+ * before proceeding with the usual removal path. kernfs will ignore later
|
|
|
+ * kernfs_remove() on self.
|
|
|
+ *
|
|
|
+ * kernfs_remove_self() can be called multiple times concurrently on the
|
|
|
+ * same kernfs_node. Only the first one actually performs removal and
|
|
|
+ * returns %true. All others will wait until the kernfs operation which
|
|
|
+ * won self-removal finishes and return %false. Note that the losers wait
|
|
|
+ * for the completion of not only the winning kernfs_remove_self() but also
|
|
|
+ * 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.
|
|
|
+ */
|
|
|
+bool kernfs_remove_self(struct kernfs_node *kn)
|
|
|
+{
|
|
|
+ bool ret;
|
|
|
+
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
+ kernfs_break_active_protection(kn);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * SUICIDAL is used to arbitrate among competing invocations. Only
|
|
|
+ * the first one will actually perform removal. When the removal
|
|
|
+ * is complete, SUICIDED is set and the active ref is restored
|
|
|
+ * while holding kernfs_mutex. The ones which lost arbitration
|
|
|
+ * waits for SUICDED && drained which can happen only after the
|
|
|
+ * enclosing kernfs operation which executed the winning instance
|
|
|
+ * of kernfs_remove_self() finished.
|
|
|
+ */
|
|
|
+ if (!(kn->flags & KERNFS_SUICIDAL)) {
|
|
|
+ kn->flags |= KERNFS_SUICIDAL;
|
|
|
+ __kernfs_remove(kn);
|
|
|
+ kn->flags |= KERNFS_SUICIDED;
|
|
|
+ ret = true;
|
|
|
+ } else {
|
|
|
+ wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq;
|
|
|
+ DEFINE_WAIT(wait);
|
|
|
+
|
|
|
+ while (true) {
|
|
|
+ prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE);
|
|
|
+
|
|
|
+ if ((kn->flags & KERNFS_SUICIDED) &&
|
|
|
+ atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
|
|
|
+ break;
|
|
|
+
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
+ schedule();
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
+ }
|
|
|
+ finish_wait(waitq, &wait);
|
|
|
+ WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb));
|
|
|
+ ret = false;
|
|
|
+ }
|
|
|
+
|
|
|
+ /*
|
|
|
+ * This must be done while holding kernfs_mutex; otherwise, waiting
|
|
|
+ * for SUICIDED && deactivated could finish prematurely.
|
|
|
+ */
|
|
|
+ kernfs_unbreak_active_protection(kn);
|
|
|
+
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
+ return ret;
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
@@ -876,7 +1208,6 @@ void kernfs_remove(struct kernfs_node *kn)
|
|
|
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
|
|
|
const void *ns)
|
|
|
{
|
|
|
- struct kernfs_addrm_cxt acxt;
|
|
|
struct kernfs_node *kn;
|
|
|
|
|
|
if (!parent) {
|
|
|
@@ -885,13 +1216,13 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
|
|
|
return -ENOENT;
|
|
|
}
|
|
|
|
|
|
- kernfs_addrm_start(&acxt);
|
|
|
+ mutex_lock(&kernfs_mutex);
|
|
|
|
|
|
kn = kernfs_find_ns(parent, name, ns);
|
|
|
if (kn)
|
|
|
- __kernfs_remove(&acxt, kn);
|
|
|
+ __kernfs_remove(kn);
|
|
|
|
|
|
- kernfs_addrm_finish(&acxt);
|
|
|
+ mutex_unlock(&kernfs_mutex);
|
|
|
|
|
|
if (kn)
|
|
|
return 0;
|
|
|
@@ -909,12 +1240,18 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
|
|
|
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
|
|
|
const char *new_name, const void *new_ns)
|
|
|
{
|
|
|
+ struct kernfs_node *old_parent;
|
|
|
+ const char *old_name = NULL;
|
|
|
int error;
|
|
|
|
|
|
+ /* can't move or rename root */
|
|
|
+ if (!kn->parent)
|
|
|
+ return -EINVAL;
|
|
|
+
|
|
|
mutex_lock(&kernfs_mutex);
|
|
|
|
|
|
error = -ENOENT;
|
|
|
- if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
|
|
|
+ if (!kernfs_active(kn) || !kernfs_active(new_parent))
|
|
|
goto out;
|
|
|
|
|
|
error = 0;
|
|
|
@@ -932,13 +1269,8 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
|
|
|
new_name = kstrdup(new_name, GFP_KERNEL);
|
|
|
if (!new_name)
|
|
|
goto out;
|
|
|
-
|
|
|
- if (kn->flags & KERNFS_STATIC_NAME)
|
|
|
- kn->flags &= ~KERNFS_STATIC_NAME;
|
|
|
- else
|
|
|
- kfree(kn->name);
|
|
|
-
|
|
|
- kn->name = new_name;
|
|
|
+ } else {
|
|
|
+ new_name = NULL;
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
@@ -946,12 +1278,29 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
|
|
|
*/
|
|
|
kernfs_unlink_sibling(kn);
|
|
|
kernfs_get(new_parent);
|
|
|
- kernfs_put(kn->parent);
|
|
|
+
|
|
|
+ /* rename_lock protects ->parent and ->name accessors */
|
|
|
+ spin_lock_irq(&kernfs_rename_lock);
|
|
|
+
|
|
|
+ old_parent = kn->parent;
|
|
|
+ kn->parent = new_parent;
|
|
|
+
|
|
|
kn->ns = new_ns;
|
|
|
+ if (new_name) {
|
|
|
+ if (!(kn->flags & KERNFS_STATIC_NAME))
|
|
|
+ old_name = kn->name;
|
|
|
+ kn->flags &= ~KERNFS_STATIC_NAME;
|
|
|
+ kn->name = new_name;
|
|
|
+ }
|
|
|
+
|
|
|
+ spin_unlock_irq(&kernfs_rename_lock);
|
|
|
+
|
|
|
kn->hash = kernfs_name_hash(kn->name, kn->ns);
|
|
|
- kn->parent = new_parent;
|
|
|
kernfs_link_sibling(kn);
|
|
|
|
|
|
+ kernfs_put(old_parent);
|
|
|
+ kfree(old_name);
|
|
|
+
|
|
|
error = 0;
|
|
|
out:
|
|
|
mutex_unlock(&kernfs_mutex);
|
|
|
@@ -974,7 +1323,7 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns,
|
|
|
struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
|
|
|
{
|
|
|
if (pos) {
|
|
|
- int valid = !(pos->flags & KERNFS_REMOVED) &&
|
|
|
+ int valid = kernfs_active(pos) &&
|
|
|
pos->parent == parent && hash == pos->hash;
|
|
|
kernfs_put(pos);
|
|
|
if (!valid)
|
|
|
@@ -993,8 +1342,8 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns,
|
|
|
break;
|
|
|
}
|
|
|
}
|
|
|
- /* Skip over entries in the wrong namespace */
|
|
|
- while (pos && pos->ns != ns) {
|
|
|
+ /* Skip over entries which are dying/dead or in the wrong namespace */
|
|
|
+ while (pos && (!kernfs_active(pos) || pos->ns != ns)) {
|
|
|
struct rb_node *node = rb_next(&pos->rb);
|
|
|
if (!node)
|
|
|
pos = NULL;
|
|
|
@@ -1008,14 +1357,15 @@ static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
|
|
|
struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
|
|
|
{
|
|
|
pos = kernfs_dir_pos(ns, parent, ino, pos);
|
|
|
- if (pos)
|
|
|
+ if (pos) {
|
|
|
do {
|
|
|
struct rb_node *node = rb_next(&pos->rb);
|
|
|
if (!node)
|
|
|
pos = NULL;
|
|
|
else
|
|
|
pos = rb_to_kn(node);
|
|
|
- } while (pos && pos->ns != ns);
|
|
|
+ } while (pos && (!kernfs_active(pos) || pos->ns != ns));
|
|
|
+ }
|
|
|
return pos;
|
|
|
}
|
|
|
|
Linus Torvalds