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-rw-r--r--include/linux/kernfs.h109
1 files changed, 86 insertions, 23 deletions
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index d267623c28cf..b0122dc6f96a 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -15,7 +15,7 @@
#include <linux/lockdep.h>
#include <linux/rbtree.h>
#include <linux/atomic.h>
-#include <linux/completion.h>
+#include <linux/wait.h>
struct file;
struct dentry;
@@ -35,16 +35,22 @@ enum kernfs_node_type {
};
#define KERNFS_TYPE_MASK 0x000f
-#define KERNFS_ACTIVE_REF KERNFS_FILE
#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK
enum kernfs_node_flag {
- KERNFS_REMOVED = 0x0010,
+ KERNFS_ACTIVATED = 0x0010,
KERNFS_NS = 0x0020,
KERNFS_HAS_SEQ_SHOW = 0x0040,
KERNFS_HAS_MMAP = 0x0080,
KERNFS_LOCKDEP = 0x0100,
KERNFS_STATIC_NAME = 0x0200,
+ KERNFS_SUICIDAL = 0x0400,
+ KERNFS_SUICIDED = 0x0800,
+};
+
+/* @flags for kernfs_create_root() */
+enum kernfs_root_flag {
+ KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
};
/* type-specific structures for kernfs_node union members */
@@ -85,17 +91,17 @@ struct kernfs_node {
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
- /* the following two fields are published */
+ /*
+ * Use kernfs_get_parent() and kernfs_name/path() instead of
+ * accessing the following two fields directly. If the node is
+ * never moved to a different parent, it is safe to access the
+ * parent directly.
+ */
struct kernfs_node *parent;
const char *name;
struct rb_node rb;
- union {
- struct completion *completion;
- struct kernfs_node *removed_list;
- } u;
-
const void *ns; /* namespace tag */
unsigned int hash; /* ns + name hash */
union {
@@ -113,12 +119,16 @@ struct kernfs_node {
};
/*
- * kernfs_dir_ops may be specified on kernfs_create_root() to support
- * directory manipulation syscalls. These optional callbacks are invoked
- * on the matching syscalls and can perform any kernfs operations which
- * don't necessarily have to be the exact operation requested.
+ * kernfs_syscall_ops may be specified on kernfs_create_root() to support
+ * syscalls. These optional callbacks are invoked on the matching syscalls
+ * and can perform any kernfs operations which don't necessarily have to be
+ * the exact operation requested. An active reference is held for each
+ * kernfs_node parameter.
*/
-struct kernfs_dir_ops {
+struct kernfs_syscall_ops {
+ int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
+ int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
+
int (*mkdir)(struct kernfs_node *parent, const char *name,
umode_t mode);
int (*rmdir)(struct kernfs_node *kn);
@@ -129,22 +139,26 @@ struct kernfs_dir_ops {
struct kernfs_root {
/* published fields */
struct kernfs_node *kn;
+ unsigned int flags; /* KERNFS_ROOT_* flags */
/* private fields, do not use outside kernfs proper */
struct ida ino_ida;
- struct kernfs_dir_ops *dir_ops;
+ struct kernfs_syscall_ops *syscall_ops;
+ wait_queue_head_t deactivate_waitq;
};
struct kernfs_open_file {
/* published fields */
struct kernfs_node *kn;
struct file *file;
+ void *priv;
/* private fields, do not use outside kernfs proper */
struct mutex mutex;
int event;
struct list_head list;
+ size_t atomic_write_len;
bool mmapped;
const struct vm_operations_struct *vm_ops;
};
@@ -171,9 +185,13 @@ struct kernfs_ops {
loff_t off);
/*
- * write() is bounced through kernel buffer and a write larger than
- * PAGE_SIZE results in partial operation of PAGE_SIZE.
+ * write() is bounced through kernel buffer. If atomic_write_len
+ * is not set, a write larger than PAGE_SIZE results in partial
+ * operations of PAGE_SIZE chunks. If atomic_write_len is set,
+ * writes upto the specified size are executed atomically but
+ * larger ones are rejected with -E2BIG.
*/
+ size_t atomic_write_len;
ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes,
loff_t off);
@@ -184,7 +202,7 @@ struct kernfs_ops {
#endif
};
-#ifdef CONFIG_SYSFS
+#ifdef CONFIG_KERNFS
static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
{
@@ -217,13 +235,22 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
return kn->flags & KERNFS_NS;
}
+int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
+char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
+ size_t buflen);
+void pr_cont_kernfs_name(struct kernfs_node *kn);
+void pr_cont_kernfs_path(struct kernfs_node *kn);
+struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
const char *name, const void *ns);
void kernfs_get(struct kernfs_node *kn);
void kernfs_put(struct kernfs_node *kn);
-struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops,
- void *priv);
+struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry);
+struct kernfs_root *kernfs_root_from_sb(struct super_block *sb);
+
+struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
+ unsigned int flags, void *priv);
void kernfs_destroy_root(struct kernfs_root *root);
struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
@@ -239,7 +266,11 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
const char *name,
struct kernfs_node *target);
+void kernfs_activate(struct kernfs_node *kn);
void kernfs_remove(struct kernfs_node *kn);
+void kernfs_break_active_protection(struct kernfs_node *kn);
+void kernfs_unbreak_active_protection(struct kernfs_node *kn);
+bool kernfs_remove_self(struct kernfs_node *kn);
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
const void *ns);
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
@@ -255,7 +286,7 @@ void kernfs_kill_sb(struct super_block *sb);
void kernfs_init(void);
-#else /* CONFIG_SYSFS */
+#else /* CONFIG_KERNFS */
static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
{ return 0; } /* whatever */
@@ -265,6 +296,19 @@ static inline void kernfs_enable_ns(struct kernfs_node *kn) { }
static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
{ return false; }
+static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
+{ return -ENOSYS; }
+
+static inline char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
+ size_t buflen)
+{ return NULL; }
+
+static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
+static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { }
+
+static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
+{ return NULL; }
+
static inline struct kernfs_node *
kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
const void *ns)
@@ -273,8 +317,15 @@ kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
static inline void kernfs_get(struct kernfs_node *kn) { }
static inline void kernfs_put(struct kernfs_node *kn) { }
+static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
+{ return NULL; }
+
+static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
+{ return NULL; }
+
static inline struct kernfs_root *
-kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
+kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags,
+ void *priv)
{ return ERR_PTR(-ENOSYS); }
static inline void kernfs_destroy_root(struct kernfs_root *root) { }
@@ -296,8 +347,13 @@ kernfs_create_link(struct kernfs_node *parent, const char *name,
struct kernfs_node *target)
{ return ERR_PTR(-ENOSYS); }
+static inline void kernfs_activate(struct kernfs_node *kn) { }
+
static inline void kernfs_remove(struct kernfs_node *kn) { }
+static inline bool kernfs_remove_self(struct kernfs_node *kn)
+{ return false; }
+
static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
const char *name, const void *ns)
{ return -ENOSYS; }
@@ -325,7 +381,7 @@ static inline void kernfs_kill_sb(struct super_block *sb) { }
static inline void kernfs_init(void) { }
-#endif /* CONFIG_SYSFS */
+#endif /* CONFIG_KERNFS */
static inline struct kernfs_node *
kernfs_find_and_get(struct kernfs_node *kn, const char *name)
@@ -367,6 +423,13 @@ static inline int kernfs_remove_by_name(struct kernfs_node *parent,
return kernfs_remove_by_name_ns(parent, name, NULL);
}
+static inline int kernfs_rename(struct kernfs_node *kn,
+ struct kernfs_node *new_parent,
+ const char *new_name)
+{
+ return kernfs_rename_ns(kn, new_parent, new_name, NULL);
+}
+
static inline struct dentry *
kernfs_mount(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, bool *new_sb_created)
generated by cgit v1.2.3 (git 2.0.4) at 2024-06-13 11:17:27 +0000