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-rw-r--r--fs/kernfs/dir.c79
-rw-r--r--fs/kernfs/file.c10
-rw-r--r--fs/kernfs/kernfs-internal.h3
-rw-r--r--fs/kernfs/symlink.c10
4 files changed, 60 insertions, 42 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 1c9130a3304..7f8afc1d08f 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -127,6 +127,7 @@ static void kernfs_unlink_sibling(struct kernfs_node *kn)
kn->parent->dir.subdirs--;
rb_erase(&kn->rb, &kn->parent->dir.children);
+ RB_CLEAR_NODE(&kn->rb);
}
/**
@@ -177,18 +178,16 @@ void kernfs_put_active(struct kernfs_node *kn)
}
/**
- * 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.
*/
-static void kernfs_deactivate(struct kernfs_node *kn)
+static void kernfs_drain(struct kernfs_node *kn)
{
struct kernfs_root *root = kernfs_root(kn);
- BUG_ON(!(kn->flags & KERNFS_REMOVED));
-
- atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
+ WARN_ON_ONCE(atomic_read(&kn->active) >= 0);
if (kernfs_lockdep(kn)) {
rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
@@ -233,13 +232,15 @@ 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);
@@ -281,8 +282,8 @@ 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)
+ /* Force fresh lookup if removed */
+ if (kn->parent && RB_EMPTY_NODE(&kn->rb))
goto out_bad;
/* The kernfs node has been moved? */
@@ -350,11 +351,12 @@ struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name,
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;
@@ -413,6 +415,8 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
struct kernfs_iattrs *ps_iattr;
int ret;
+ WARN_ON_ONCE(atomic_read(&parent->active) < 0);
+
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);
@@ -422,9 +426,6 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
if (kernfs_type(parent) != KERNFS_DIR)
return -EINVAL;
- if (parent->flags & KERNFS_REMOVED)
- return -ENOENT;
-
kn->hash = kernfs_name_hash(kn->name, kn->ns);
kn->parent = parent;
kernfs_get(parent);
@@ -441,8 +442,7 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
}
/* Mark the entry added into directory tree */
- kn->flags &= ~KERNFS_REMOVED;
-
+ atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
return 0;
}
@@ -470,7 +470,7 @@ static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
* Removal can be called multiple times on the same node. Only the
* first invocation is effective and puts the base ref.
*/
- if (kn->flags & KERNFS_REMOVED)
+ if (atomic_read(&kn->active) < 0)
return;
if (kn->parent) {
@@ -484,7 +484,7 @@ static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
}
}
- kn->flags |= KERNFS_REMOVED;
+ atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
kn->u.removed_list = acxt->removed;
acxt->removed = kn;
}
@@ -512,7 +512,7 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
acxt->removed = kn->u.removed_list;
- kernfs_deactivate(kn);
+ kernfs_drain(kn);
kernfs_unmap_bin_file(kn);
kernfs_put(kn);
}
@@ -610,7 +610,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
return ERR_PTR(-ENOMEM);
}
- kn->flags &= ~KERNFS_REMOVED;
+ atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
kn->priv = priv;
kn->dir.root = root;
@@ -662,9 +662,13 @@ 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, parent);
- kernfs_addrm_finish(&acxt);
+ rc = -ENOENT;
+ if (kernfs_get_active(parent)) {
+ kernfs_addrm_start(&acxt);
+ rc = kernfs_add_one(&acxt, kn, parent);
+ kernfs_addrm_finish(&acxt);
+ kernfs_put_active(parent);
+ }
if (!rc)
return kn;
@@ -899,27 +903,29 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
{
int error;
- mutex_lock(&kernfs_mutex);
-
error = -ENOENT;
- if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
+ if (!kernfs_get_active(new_parent))
goto out;
+ if (!kernfs_get_active(kn))
+ goto out_put_new_parent;
+
+ mutex_lock(&kernfs_mutex);
error = 0;
if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
(strcmp(kn->name, new_name) == 0))
- goto out; /* nothing to rename */
+ goto out_unlock; /* nothing to rename */
error = -EEXIST;
if (kernfs_find_ns(new_parent, new_name, new_ns))
- goto out;
+ goto out_unlock;
/* rename kernfs_node */
if (strcmp(kn->name, new_name) != 0) {
error = -ENOMEM;
new_name = kstrdup(new_name, GFP_KERNEL);
if (!new_name)
- goto out;
+ goto out_unlock;
if (kn->flags & KERNFS_STATIC_NAME)
kn->flags &= ~KERNFS_STATIC_NAME;
@@ -941,8 +947,12 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
kernfs_link_sibling(kn);
error = 0;
- out:
+out_unlock:
mutex_unlock(&kernfs_mutex);
+ kernfs_put_active(kn);
+out_put_new_parent:
+ kernfs_put_active(new_parent);
+out:
return error;
}
@@ -962,8 +972,7 @@ 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) &&
- pos->parent == parent && hash == pos->hash;
+ int valid = pos->parent == parent && hash == pos->hash;
kernfs_put(pos);
if (!valid)
pos = NULL;
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index bdd38854ef6..231a171f48b 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -856,9 +856,13 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
if (ops->mmap)
kn->flags |= KERNFS_HAS_MMAP;
- kernfs_addrm_start(&acxt);
- rc = kernfs_add_one(&acxt, kn, parent);
- kernfs_addrm_finish(&acxt);
+ rc = -ENOENT;
+ if (kernfs_get_active(parent)) {
+ kernfs_addrm_start(&acxt);
+ rc = kernfs_add_one(&acxt, kn, parent);
+ kernfs_addrm_finish(&acxt);
+ kernfs_put_active(parent);
+ }
if (rc) {
kernfs_put(kn);
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index c6ba5bc37a9..57a93f4d645 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -26,7 +26,8 @@ struct kernfs_iattrs {
struct simple_xattrs xattrs;
};
-#define KN_DEACTIVATED_BIAS INT_MIN
+/* +1 to avoid triggering overflow warning when negating it */
+#define KN_DEACTIVATED_BIAS (INT_MIN + 1)
/* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index a03e26036ef..b2c106ca343 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -40,9 +40,13 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
kn->symlink.target_kn = target;
kernfs_get(target); /* ref owned by symlink */
- kernfs_addrm_start(&acxt);
- error = kernfs_add_one(&acxt, kn, parent);
- kernfs_addrm_finish(&acxt);
+ error = -ENOENT;
+ if (kernfs_get_active(parent)) {
+ kernfs_addrm_start(&acxt);
+ error = kernfs_add_one(&acxt, kn, parent);
+ kernfs_addrm_finish(&acxt);
+ kernfs_put_active(parent);
+ }
if (!error)
return kn;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-28 16:12:06 +0000