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-rw-r--r--kernel/include/linux/fsnotify_backend.h405
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diff --git a/kernel/include/linux/fsnotify_backend.h b/kernel/include/linux/fsnotify_backend.h
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index 000000000..0f313f93c
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+++ b/kernel/include/linux/fsnotify_backend.h
@@ -0,0 +1,405 @@
+/*
+ * Filesystem access notification for Linux
+ *
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ */
+
+#ifndef __LINUX_FSNOTIFY_BACKEND_H
+#define __LINUX_FSNOTIFY_BACKEND_H
+
+#ifdef __KERNEL__
+
+#include <linux/idr.h> /* inotify uses this */
+#include <linux/fs.h> /* struct inode */
+#include <linux/list.h>
+#include <linux/path.h> /* struct path */
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+
+/*
+ * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily
+ * convert between them. dnotify only needs conversion at watch creation
+ * so no perf loss there. fanotify isn't defined yet, so it can use the
+ * wholes if it needs more events.
+ */
+#define FS_ACCESS 0x00000001 /* File was accessed */
+#define FS_MODIFY 0x00000002 /* File was modified */
+#define FS_ATTRIB 0x00000004 /* Metadata changed */
+#define FS_CLOSE_WRITE 0x00000008 /* Writtable file was closed */
+#define FS_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
+#define FS_OPEN 0x00000020 /* File was opened */
+#define FS_MOVED_FROM 0x00000040 /* File was moved from X */
+#define FS_MOVED_TO 0x00000080 /* File was moved to Y */
+#define FS_CREATE 0x00000100 /* Subfile was created */
+#define FS_DELETE 0x00000200 /* Subfile was deleted */
+#define FS_DELETE_SELF 0x00000400 /* Self was deleted */
+#define FS_MOVE_SELF 0x00000800 /* Self was moved */
+
+#define FS_UNMOUNT 0x00002000 /* inode on umount fs */
+#define FS_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
+#define FS_IN_IGNORED 0x00008000 /* last inotify event here */
+
+#define FS_OPEN_PERM 0x00010000 /* open event in an permission hook */
+#define FS_ACCESS_PERM 0x00020000 /* access event in a permissions hook */
+
+#define FS_EXCL_UNLINK 0x04000000 /* do not send events if object is unlinked */
+#define FS_ISDIR 0x40000000 /* event occurred against dir */
+#define FS_IN_ONESHOT 0x80000000 /* only send event once */
+
+#define FS_DN_RENAME 0x10000000 /* file renamed */
+#define FS_DN_MULTISHOT 0x20000000 /* dnotify multishot */
+
+/* This inode cares about things that happen to its children. Always set for
+ * dnotify and inotify. */
+#define FS_EVENT_ON_CHILD 0x08000000
+
+/* This is a list of all events that may get sent to a parernt based on fs event
+ * happening to inodes inside that directory */
+#define FS_EVENTS_POSS_ON_CHILD (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
+ FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
+ FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
+ FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)
+
+#define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO)
+
+#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
+
+#define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
+ FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
+ FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
+ FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
+ FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
+ FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
+ FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
+ FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
+
+struct fsnotify_group;
+struct fsnotify_event;
+struct fsnotify_mark;
+struct fsnotify_event_private_data;
+struct fsnotify_fname;
+
+/*
+ * Each group much define these ops. The fsnotify infrastructure will call
+ * these operations for each relevant group.
+ *
+ * should_send_event - given a group, inode, and mask this function determines
+ * if the group is interested in this event.
+ * handle_event - main call for a group to handle an fs event
+ * free_group_priv - called when a group refcnt hits 0 to clean up the private union
+ * freeing_mark - called when a mark is being destroyed for some reason. The group
+ * MUST be holding a reference on each mark and that reference must be
+ * dropped in this function. inotify uses this function to send
+ * userspace messages that marks have been removed.
+ */
+struct fsnotify_ops {
+ int (*handle_event)(struct fsnotify_group *group,
+ struct inode *inode,
+ struct fsnotify_mark *inode_mark,
+ struct fsnotify_mark *vfsmount_mark,
+ u32 mask, void *data, int data_type,
+ const unsigned char *file_name, u32 cookie);
+ void (*free_group_priv)(struct fsnotify_group *group);
+ void (*freeing_mark)(struct fsnotify_mark *mark, struct fsnotify_group *group);
+ void (*free_event)(struct fsnotify_event *event);
+};
+
+/*
+ * all of the information about the original object we want to now send to
+ * a group. If you want to carry more info from the accessing task to the
+ * listener this structure is where you need to be adding fields.
+ */
+struct fsnotify_event {
+ struct list_head list;
+ /* inode may ONLY be dereferenced during handle_event(). */
+ struct inode *inode; /* either the inode the event happened to or its parent */
+ u32 mask; /* the type of access, bitwise OR for FS_* event types */
+};
+
+/*
+ * A group is a "thing" that wants to receive notification about filesystem
+ * events. The mask holds the subset of event types this group cares about.
+ * refcnt on a group is up to the implementor and at any moment if it goes 0
+ * everything will be cleaned up.
+ */
+struct fsnotify_group {
+ /*
+ * How the refcnt is used is up to each group. When the refcnt hits 0
+ * fsnotify will clean up all of the resources associated with this group.
+ * As an example, the dnotify group will always have a refcnt=1 and that
+ * will never change. Inotify, on the other hand, has a group per
+ * inotify_init() and the refcnt will hit 0 only when that fd has been
+ * closed.
+ */
+ atomic_t refcnt; /* things with interest in this group */
+
+ const struct fsnotify_ops *ops; /* how this group handles things */
+
+ /* needed to send notification to userspace */
+ struct mutex notification_mutex; /* protect the notification_list */
+ struct list_head notification_list; /* list of event_holder this group needs to send to userspace */
+ wait_queue_head_t notification_waitq; /* read() on the notification file blocks on this waitq */
+ unsigned int q_len; /* events on the queue */
+ unsigned int max_events; /* maximum events allowed on the list */
+ /*
+ * Valid fsnotify group priorities. Events are send in order from highest
+ * priority to lowest priority. We default to the lowest priority.
+ */
+ #define FS_PRIO_0 0 /* normal notifiers, no permissions */
+ #define FS_PRIO_1 1 /* fanotify content based access control */
+ #define FS_PRIO_2 2 /* fanotify pre-content access */
+ unsigned int priority;
+
+ /* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
+ struct mutex mark_mutex; /* protect marks_list */
+ atomic_t num_marks; /* 1 for each mark and 1 for not being
+ * past the point of no return when freeing
+ * a group */
+ struct list_head marks_list; /* all inode marks for this group */
+
+ struct fasync_struct *fsn_fa; /* async notification */
+
+ struct fsnotify_event *overflow_event; /* Event we queue when the
+ * notification list is too
+ * full */
+
+ /* groups can define private fields here or use the void *private */
+ union {
+ void *private;
+#ifdef CONFIG_INOTIFY_USER
+ struct inotify_group_private_data {
+ spinlock_t idr_lock;
+ struct idr idr;
+ struct user_struct *user;
+ } inotify_data;
+#endif
+#ifdef CONFIG_FANOTIFY
+ struct fanotify_group_private_data {
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+ /* allows a group to block waiting for a userspace response */
+ spinlock_t access_lock;
+ struct list_head access_list;
+ wait_queue_head_t access_waitq;
+ atomic_t bypass_perm;
+#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
+ int f_flags;
+ unsigned int max_marks;
+ struct user_struct *user;
+ } fanotify_data;
+#endif /* CONFIG_FANOTIFY */
+ };
+};
+
+/* when calling fsnotify tell it if the data is a path or inode */
+#define FSNOTIFY_EVENT_NONE 0
+#define FSNOTIFY_EVENT_PATH 1
+#define FSNOTIFY_EVENT_INODE 2
+
+/*
+ * a mark is simply an object attached to an in core inode which allows an
+ * fsnotify listener to indicate they are either no longer interested in events
+ * of a type matching mask or only interested in those events.
+ *
+ * these are flushed when an inode is evicted from core and may be flushed
+ * when the inode is modified (as seen by fsnotify_access). Some fsnotify users
+ * (such as dnotify) will flush these when the open fd is closed and not at
+ * inode eviction or modification.
+ */
+struct fsnotify_mark {
+ __u32 mask; /* mask this mark is for */
+ /* we hold ref for each i_list and g_list. also one ref for each 'thing'
+ * in kernel that found and may be using this mark. */
+ atomic_t refcnt; /* active things looking at this mark */
+ struct fsnotify_group *group; /* group this mark is for */
+ struct list_head g_list; /* list of marks by group->i_fsnotify_marks
+ * Also reused for queueing mark into
+ * destroy_list when it's waiting for
+ * the end of SRCU period before it can
+ * be freed */
+ spinlock_t lock; /* protect group and inode */
+ struct hlist_node obj_list; /* list of marks for inode / vfsmount */
+ struct list_head free_list; /* tmp list used when freeing this mark */
+ union {
+ struct inode *inode; /* inode this mark is associated with */
+ struct vfsmount *mnt; /* vfsmount this mark is associated with */
+ };
+ __u32 ignored_mask; /* events types to ignore */
+#define FSNOTIFY_MARK_FLAG_INODE 0x01
+#define FSNOTIFY_MARK_FLAG_VFSMOUNT 0x02
+#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04
+#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08
+#define FSNOTIFY_MARK_FLAG_ALIVE 0x10
+ unsigned int flags; /* vfsmount or inode mark? */
+ void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */
+};
+
+#ifdef CONFIG_FSNOTIFY
+
+/* called from the vfs helpers */
+
+/* main fsnotify call to send events */
+extern int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+ const unsigned char *name, u32 cookie);
+extern int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
+extern void __fsnotify_inode_delete(struct inode *inode);
+extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
+extern u32 fsnotify_get_cookie(void);
+
+static inline int fsnotify_inode_watches_children(struct inode *inode)
+{
+ /* FS_EVENT_ON_CHILD is set if the inode may care */
+ if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
+ return 0;
+ /* this inode might care about child events, does it care about the
+ * specific set of events that can happen on a child? */
+ return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
+}
+
+/*
+ * Update the dentry with a flag indicating the interest of its parent to receive
+ * filesystem events when those events happens to this dentry->d_inode.
+ */
+static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
+{
+ struct dentry *parent;
+
+ assert_spin_locked(&dentry->d_lock);
+
+ /*
+ * Serialisation of setting PARENT_WATCHED on the dentries is provided
+ * by d_lock. If inotify_inode_watched changes after we have taken
+ * d_lock, the following __fsnotify_update_child_dentry_flags call will
+ * find our entry, so it will spin until we complete here, and update
+ * us with the new state.
+ */
+ parent = dentry->d_parent;
+ if (parent->d_inode && fsnotify_inode_watches_children(parent->d_inode))
+ dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
+ else
+ dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
+}
+
+/*
+ * fsnotify_d_instantiate - instantiate a dentry for inode
+ */
+static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (!inode)
+ return;
+
+ spin_lock(&dentry->d_lock);
+ __fsnotify_update_dcache_flags(dentry);
+ spin_unlock(&dentry->d_lock);
+}
+
+/* called from fsnotify listeners, such as fanotify or dnotify */
+
+/* create a new group */
+extern struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops);
+/* get reference to a group */
+extern void fsnotify_get_group(struct fsnotify_group *group);
+/* drop reference on a group from fsnotify_alloc_group */
+extern void fsnotify_put_group(struct fsnotify_group *group);
+/* destroy group */
+extern void fsnotify_destroy_group(struct fsnotify_group *group);
+/* fasync handler function */
+extern int fsnotify_fasync(int fd, struct file *file, int on);
+/* Free event from memory */
+extern void fsnotify_destroy_event(struct fsnotify_group *group,
+ struct fsnotify_event *event);
+/* attach the event to the group notification queue */
+extern int fsnotify_add_event(struct fsnotify_group *group,
+ struct fsnotify_event *event,
+ int (*merge)(struct list_head *,
+ struct fsnotify_event *));
+/* Remove passed event from groups notification queue */
+extern void fsnotify_remove_event(struct fsnotify_group *group, struct fsnotify_event *event);
+/* true if the group notification queue is empty */
+extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
+/* return, but do not dequeue the first event on the notification queue */
+extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group);
+/* return AND dequeue the first event on the notification queue */
+extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group);
+
+/* functions used to manipulate the marks attached to inodes */
+
+/* run all marks associated with a vfsmount and update mnt->mnt_fsnotify_mask */
+extern void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt);
+/* run all marks associated with an inode and update inode->i_fsnotify_mask */
+extern void fsnotify_recalc_inode_mask(struct inode *inode);
+extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(struct fsnotify_mark *mark));
+/* find (and take a reference) to a mark associated with group and inode */
+extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode);
+/* find (and take a reference) to a mark associated with group and vfsmount */
+extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt);
+/* copy the values from old into new */
+extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old);
+/* set the ignored_mask of a mark */
+extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask);
+/* set the mask of a mark (might pin the object into memory */
+extern void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask);
+/* attach the mark to both the group and the inode */
+extern int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group,
+ struct inode *inode, struct vfsmount *mnt, int allow_dups);
+extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark, struct fsnotify_group *group,
+ struct inode *inode, struct vfsmount *mnt, int allow_dups);
+/* given a group and a mark, flag mark to be freed when all references are dropped */
+extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
+ struct fsnotify_group *group);
+extern void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark,
+ struct fsnotify_group *group);
+/* run all the marks in a group, and clear all of the vfsmount marks */
+extern void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group);
+/* run all the marks in a group, and clear all of the inode marks */
+extern void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group);
+/* run all the marks in a group, and clear all of the marks where mark->flags & flags is true*/
+extern void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, unsigned int flags);
+/* run all the marks in a group, and flag them to be freed */
+extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group);
+extern void fsnotify_get_mark(struct fsnotify_mark *mark);
+extern void fsnotify_put_mark(struct fsnotify_mark *mark);
+extern void fsnotify_unmount_inodes(struct list_head *list);
+
+/* put here because inotify does some weird stuff when destroying watches */
+extern void fsnotify_init_event(struct fsnotify_event *event,
+ struct inode *to_tell, u32 mask);
+
+#else
+
+static inline int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+ const unsigned char *name, u32 cookie)
+{
+ return 0;
+}
+
+static inline int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+{
+ return 0;
+}
+
+static inline void __fsnotify_inode_delete(struct inode *inode)
+{}
+
+static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
+{}
+
+static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
+{}
+
+static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
+{}
+
+static inline u32 fsnotify_get_cookie(void)
+{
+ return 0;
+}
+
+static inline void fsnotify_unmount_inodes(struct list_head *list)
+{}
+
+#endif /* CONFIG_FSNOTIFY */
+
+#endif /* __KERNEL __ */
+
+#endif /* __LINUX_FSNOTIFY_BACKEND_H */