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authorLinus Torvalds <torvalds@linux-foundation.org>2009-06-11 14:22:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-11 14:22:55 -0700
commit3bb66d7f8cc31537a3170c9bb82b38e538b984c5 (patch)
treee7174a8e9b805e056c3b0e510789a611ce4eeb1c /include
parent512626a04e72aca60effe111fa0333ed0b195d21 (diff)
parenta092ee20fd33d2df0990dcbf2235afc181612818 (diff)
Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
* 'for-linus' of git://git.infradead.org/users/eparis/notify: fsnotify: allow groups to set freeing_mark to null inotify/dnotify: should_send_event shouldn't match on FS_EVENT_ON_CHILD dnotify: do not bother to lock entry->lock when reading mask dnotify: do not use ?true:false when assigning to a bool fsnotify: move events should indicate the event was on a child inotify: reimplement inotify using fsnotify fsnotify: handle filesystem unmounts with fsnotify marks fsnotify: fsnotify marks on inodes pin them in core fsnotify: allow groups to add private data to events fsnotify: add correlations between events fsnotify: include pathnames with entries when possible fsnotify: generic notification queue and waitq dnotify: reimplement dnotify using fsnotify fsnotify: parent event notification fsnotify: add marks to inodes so groups can interpret how to handle those inodes fsnotify: unified filesystem notification backend
Diffstat (limited to 'include')
-rw-r--r--include/linux/dcache.h4
-rw-r--r--include/linux/dnotify.h29
-rw-r--r--include/linux/fs.h6
-rw-r--r--include/linux/fsnotify.h199
-rw-r--r--include/linux/fsnotify_backend.h387
5 files changed, 521 insertions, 104 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 15156364d19..97978004338 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -180,10 +180,12 @@ d_iput: no no no yes
#define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */
#define DCACHE_UNHASHED 0x0010
-#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched */
+#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched by inotify */
#define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */
+#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080 /* Parent inode is watched by some fsnotify listener */
+
extern spinlock_t dcache_lock;
extern seqlock_t rename_lock;
diff --git a/include/linux/dnotify.h b/include/linux/dnotify.h
index 102a902b439..ecc06286226 100644
--- a/include/linux/dnotify.h
+++ b/include/linux/dnotify.h
@@ -10,7 +10,7 @@
struct dnotify_struct {
struct dnotify_struct * dn_next;
- unsigned long dn_mask;
+ __u32 dn_mask;
int dn_fd;
struct file * dn_filp;
fl_owner_t dn_owner;
@@ -21,23 +21,18 @@ struct dnotify_struct {
#ifdef CONFIG_DNOTIFY
-extern void __inode_dir_notify(struct inode *, unsigned long);
+#define DNOTIFY_ALL_EVENTS (FS_DELETE | FS_DELETE_CHILD |\
+ FS_MODIFY | FS_MODIFY_CHILD |\
+ FS_ACCESS | FS_ACCESS_CHILD |\
+ FS_ATTRIB | FS_ATTRIB_CHILD |\
+ FS_CREATE | FS_DN_RENAME |\
+ FS_MOVED_FROM | FS_MOVED_TO)
+
extern void dnotify_flush(struct file *, fl_owner_t);
extern int fcntl_dirnotify(int, struct file *, unsigned long);
-extern void dnotify_parent(struct dentry *, unsigned long);
-
-static inline void inode_dir_notify(struct inode *inode, unsigned long event)
-{
- if (inode->i_dnotify_mask & (event))
- __inode_dir_notify(inode, event);
-}
#else
-static inline void __inode_dir_notify(struct inode *inode, unsigned long event)
-{
-}
-
static inline void dnotify_flush(struct file *filp, fl_owner_t id)
{
}
@@ -47,14 +42,6 @@ static inline int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
return -EINVAL;
}
-static inline void dnotify_parent(struct dentry *dentry, unsigned long event)
-{
-}
-
-static inline void inode_dir_notify(struct inode *inode, unsigned long event)
-{
-}
-
#endif /* CONFIG_DNOTIFY */
#endif /* __KERNEL __ */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 83d6b439724..323b5ce474c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -755,9 +755,9 @@ struct inode {
__u32 i_generation;
-#ifdef CONFIG_DNOTIFY
- unsigned long i_dnotify_mask; /* Directory notify events */
- struct dnotify_struct *i_dnotify; /* for directory notifications */
+#ifdef CONFIG_FSNOTIFY
+ __u32 i_fsnotify_mask; /* all events this inode cares about */
+ struct hlist_head i_fsnotify_mark_entries; /* fsnotify mark entries */
#endif
#ifdef CONFIG_INOTIFY
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 00fbd5b245c..936f9aa8bb9 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -13,6 +13,7 @@
#include <linux/dnotify.h>
#include <linux/inotify.h>
+#include <linux/fsnotify_backend.h>
#include <linux/audit.h>
/*
@@ -22,19 +23,45 @@
static inline void fsnotify_d_instantiate(struct dentry *entry,
struct inode *inode)
{
+ __fsnotify_d_instantiate(entry, inode);
+
inotify_d_instantiate(entry, inode);
}
+/* Notify this dentry's parent about a child's events. */
+static inline void fsnotify_parent(struct dentry *dentry, __u32 mask)
+{
+ __fsnotify_parent(dentry, mask);
+
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+}
+
/*
* fsnotify_d_move - entry has been moved
* Called with dcache_lock and entry->d_lock held.
*/
static inline void fsnotify_d_move(struct dentry *entry)
{
+ /*
+ * On move we need to update entry->d_flags to indicate if the new parent
+ * cares about events from this entry.
+ */
+ __fsnotify_update_dcache_flags(entry);
+
inotify_d_move(entry);
}
/*
+ * fsnotify_link_count - inode's link count changed
+ */
+static inline void fsnotify_link_count(struct inode *inode)
+{
+ inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL);
+
+ fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+}
+
+/*
* fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
*/
static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
@@ -42,42 +69,62 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
int isdir, struct inode *target, struct dentry *moved)
{
struct inode *source = moved->d_inode;
- u32 cookie = inotify_get_cookie();
+ u32 in_cookie = inotify_get_cookie();
+ u32 fs_cookie = fsnotify_get_cookie();
+ __u32 old_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_FROM);
+ __u32 new_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_TO);
if (old_dir == new_dir)
- inode_dir_notify(old_dir, DN_RENAME);
- else {
- inode_dir_notify(old_dir, DN_DELETE);
- inode_dir_notify(new_dir, DN_CREATE);
- }
+ old_dir_mask |= FS_DN_RENAME;
- if (isdir)
+ if (isdir) {
isdir = IN_ISDIR;
- inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir,cookie,old_name,
+ old_dir_mask |= FS_IN_ISDIR;
+ new_dir_mask |= FS_IN_ISDIR;
+ }
+
+ inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir, in_cookie, old_name,
source);
- inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name,
+ inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, in_cookie, new_name,
source);
+ fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE, old_name, fs_cookie);
+ fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE, new_name, fs_cookie);
+
if (target) {
inotify_inode_queue_event(target, IN_DELETE_SELF, 0, NULL, NULL);
inotify_inode_is_dead(target);
+
+ /* this is really a link_count change not a removal */
+ fsnotify_link_count(target);
}
if (source) {
inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL, NULL);
+ fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
audit_inode_child(new_name, moved, new_dir);
}
/*
+ * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
+ */
+static inline void fsnotify_inode_delete(struct inode *inode)
+{
+ __fsnotify_inode_delete(inode);
+}
+
+/*
* fsnotify_nameremove - a filename was removed from a directory
*/
static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
{
+ __u32 mask = FS_DELETE;
+
if (isdir)
- isdir = IN_ISDIR;
- dnotify_parent(dentry, DN_DELETE);
- inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name);
+ mask |= FS_IN_ISDIR;
+
+ fsnotify_parent(dentry, mask);
}
/*
@@ -87,14 +134,9 @@ static inline void fsnotify_inoderemove(struct inode *inode)
{
inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL, NULL);
inotify_inode_is_dead(inode);
-}
-/*
- * fsnotify_link_count - inode's link count changed
- */
-static inline void fsnotify_link_count(struct inode *inode)
-{
- inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL);
+ fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+ __fsnotify_inode_delete(inode);
}
/*
@@ -102,10 +144,11 @@ static inline void fsnotify_link_count(struct inode *inode)
*/
static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
{
- inode_dir_notify(inode, DN_CREATE);
inotify_inode_queue_event(inode, IN_CREATE, 0, dentry->d_name.name,
dentry->d_inode);
audit_inode_child(dentry->d_name.name, dentry, inode);
+
+ fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
}
/*
@@ -115,11 +158,12 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
*/
static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
{
- inode_dir_notify(dir, DN_CREATE);
inotify_inode_queue_event(dir, IN_CREATE, 0, new_dentry->d_name.name,
inode);
fsnotify_link_count(inode);
audit_inode_child(new_dentry->d_name.name, new_dentry, dir);
+
+ fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
}
/*
@@ -127,10 +171,13 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
*/
static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
{
- inode_dir_notify(inode, DN_CREATE);
- inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0,
- dentry->d_name.name, dentry->d_inode);
+ __u32 mask = (FS_CREATE | FS_IN_ISDIR);
+ struct inode *d_inode = dentry->d_inode;
+
+ inotify_inode_queue_event(inode, mask, 0, dentry->d_name.name, d_inode);
audit_inode_child(dentry->d_name.name, dentry, inode);
+
+ fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
}
/*
@@ -139,14 +186,15 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
static inline void fsnotify_access(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_ACCESS;
+ __u32 mask = FS_ACCESS;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- dnotify_parent(dentry, DN_ACCESS);
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
@@ -155,14 +203,15 @@ static inline void fsnotify_access(struct dentry *dentry)
static inline void fsnotify_modify(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_MODIFY;
+ __u32 mask = FS_MODIFY;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- dnotify_parent(dentry, DN_MODIFY);
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
@@ -171,13 +220,15 @@ static inline void fsnotify_modify(struct dentry *dentry)
static inline void fsnotify_open(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_OPEN;
+ __u32 mask = FS_OPEN;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
@@ -187,15 +238,16 @@ static inline void fsnotify_close(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
- const char *name = dentry->d_name.name;
fmode_t mode = file->f_mode;
- u32 mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE;
+ __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- inotify_dentry_parent_queue_event(dentry, mask, 0, name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
/*
@@ -204,13 +256,15 @@ static inline void fsnotify_close(struct file *file)
static inline void fsnotify_xattr(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_ATTRIB;
+ __u32 mask = FS_ATTRIB;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
@@ -220,50 +274,37 @@ static inline void fsnotify_xattr(struct dentry *dentry)
static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
{
struct inode *inode = dentry->d_inode;
- int dn_mask = 0;
- u32 in_mask = 0;
+ __u32 mask = 0;
+
+ if (ia_valid & ATTR_UID)
+ mask |= FS_ATTRIB;
+ if (ia_valid & ATTR_GID)
+ mask |= FS_ATTRIB;
+ if (ia_valid & ATTR_SIZE)
+ mask |= FS_MODIFY;
- if (ia_valid & ATTR_UID) {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- }
- if (ia_valid & ATTR_GID) {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- }
- if (ia_valid & ATTR_SIZE) {
- in_mask |= IN_MODIFY;
- dn_mask |= DN_MODIFY;
- }
/* both times implies a utime(s) call */
if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
- {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- } else if (ia_valid & ATTR_ATIME) {
- in_mask |= IN_ACCESS;
- dn_mask |= DN_ACCESS;
- } else if (ia_valid & ATTR_MTIME) {
- in_mask |= IN_MODIFY;
- dn_mask |= DN_MODIFY;
- }
- if (ia_valid & ATTR_MODE) {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- }
+ mask |= FS_ATTRIB;
+ else if (ia_valid & ATTR_ATIME)
+ mask |= FS_ACCESS;
+ else if (ia_valid & ATTR_MTIME)
+ mask |= FS_MODIFY;
+
+ if (ia_valid & ATTR_MODE)
+ mask |= FS_ATTRIB;
- if (dn_mask)
- dnotify_parent(dentry, dn_mask);
- if (in_mask) {
+ if (mask) {
if (S_ISDIR(inode->i_mode))
- in_mask |= IN_ISDIR;
- inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL);
- inotify_dentry_parent_queue_event(dentry, in_mask, 0,
- dentry->d_name.name);
+ mask |= FS_IN_ISDIR;
+ inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
}
-#ifdef CONFIG_INOTIFY /* inotify helpers */
+#if defined(CONFIG_INOTIFY) || defined(CONFIG_FSNOTIFY) /* notify helpers */
/*
* fsnotify_oldname_init - save off the old filename before we change it
@@ -281,7 +322,7 @@ static inline void fsnotify_oldname_free(const char *old_name)
kfree(old_name);
}
-#else /* CONFIG_INOTIFY */
+#else /* CONFIG_INOTIFY || CONFIG_FSNOTIFY */
static inline const char *fsnotify_oldname_init(const char *name)
{
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
new file mode 100644
index 00000000000..44848aa830d
--- /dev/null
+++ b/include/linux/fsnotify_backend.h
@@ -0,0 +1,387 @@
+/*
+ * 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 <asm/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_IN_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)
+
+/* listeners that hard code group numbers near the top */
+#define DNOTIFY_GROUP_NUM UINT_MAX
+#define INOTIFY_GROUP_NUM (DNOTIFY_GROUP_NUM-1)
+
+struct fsnotify_group;
+struct fsnotify_event;
+struct fsnotify_mark_entry;
+struct fsnotify_event_private_data;
+
+/*
+ * 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 - this means that a mark has been flagged to die when everything
+ * finishes using it. The function is supplied with what must be a
+ * valid group and inode to use to clean up.
+ */
+struct fsnotify_ops {
+ bool (*should_send_event)(struct fsnotify_group *group, struct inode *inode, __u32 mask);
+ int (*handle_event)(struct fsnotify_group *group, struct fsnotify_event *event);
+ void (*free_group_priv)(struct fsnotify_group *group);
+ void (*freeing_mark)(struct fsnotify_mark_entry *entry, struct fsnotify_group *group);
+ void (*free_event_priv)(struct fsnotify_event_private_data *priv);
+};
+
+/*
+ * 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 {
+ /*
+ * global list of all groups receiving events from fsnotify.
+ * anchored by fsnotify_groups and protected by either fsnotify_grp_mutex
+ * or fsnotify_grp_srcu depending on write vs read.
+ */
+ struct list_head group_list;
+
+ /*
+ * Defines all of the event types in which this group is interested.
+ * This mask is a bitwise OR of the FS_* events from above. Each time
+ * this mask changes for a group (if it changes) the correct functions
+ * must be called to update the global structures which indicate global
+ * interest in event types.
+ */
+ __u32 mask;
+
+ /*
+ * 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 */
+ unsigned int group_num; /* simply prevents accidental group collision */
+
+ 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 */
+
+ /* stores all fastapth entries assoc with this group so they can be cleaned on unregister */
+ spinlock_t mark_lock; /* protect mark_entries list */
+ atomic_t num_marks; /* 1 for each mark entry and 1 for not being
+ * past the point of no return when freeing
+ * a group */
+ struct list_head mark_entries; /* all inode mark entries for this group */
+
+ /* prevents double list_del of group_list. protected by global fsnotify_grp_mutex */
+ bool on_group_list;
+
+ /* 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;
+ u32 last_wd;
+ struct fasync_struct *fa; /* async notification */
+ struct user_struct *user;
+ } inotify_data;
+#endif
+ };
+};
+
+/*
+ * A single event can be queued in multiple group->notification_lists.
+ *
+ * each group->notification_list will point to an event_holder which in turns points
+ * to the actual event that needs to be sent to userspace.
+ *
+ * Seemed cheaper to create a refcnt'd event and a small holder for every group
+ * than create a different event for every group
+ *
+ */
+struct fsnotify_event_holder {
+ struct fsnotify_event *event;
+ struct list_head event_list;
+};
+
+/*
+ * Inotify needs to tack data onto an event. This struct lets us later find the
+ * correct private data of the correct group.
+ */
+struct fsnotify_event_private_data {
+ struct fsnotify_group *group;
+ struct list_head event_list;
+};
+
+/*
+ * 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 {
+ /*
+ * If we create an event we are also likely going to need a holder
+ * to link to a group. So embed one holder in the event. Means only
+ * one allocation for the common case where we only have one group
+ */
+ struct fsnotify_event_holder holder;
+ spinlock_t lock; /* protection for the associated event_holder and private_list */
+ /* to_tell may ONLY be dereferenced during handle_event(). */
+ struct inode *to_tell; /* either the inode the event happened to or its parent */
+ /*
+ * depending on the event type we should have either a path or inode
+ * We hold a reference on path, but NOT on inode. Since we have the ref on
+ * the path, it may be dereferenced at any point during this object's
+ * lifetime. That reference is dropped when this object's refcnt hits
+ * 0. If this event contains an inode instead of a path, the inode may
+ * ONLY be used during handle_event().
+ */
+ union {
+ struct path path;
+ struct inode *inode;
+ };
+/* 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
+#define FSNOTIFY_EVENT_FILE 3
+ int data_type; /* which of the above union we have */
+ atomic_t refcnt; /* how many groups still are using/need to send this event */
+ __u32 mask; /* the type of access, bitwise OR for FS_* event types */
+
+ u32 sync_cookie; /* used to corrolate events, namely inotify mv events */
+ char *file_name;
+ size_t name_len;
+
+ struct list_head private_data_list; /* groups can store private data here */
+};
+
+/*
+ * a mark is simply an entry 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_entry {
+ __u32 mask; /* mask this mark entry 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 inode *inode; /* inode this entry is associated with */
+ struct fsnotify_group *group; /* group this mark entry is for */
+ struct hlist_node i_list; /* list of mark_entries by inode->i_fsnotify_mark_entries */
+ struct list_head g_list; /* list of mark_entries by group->i_fsnotify_mark_entries */
+ spinlock_t lock; /* protect group, inode, and killme */
+ struct list_head free_i_list; /* tmp list used when freeing this mark */
+ struct list_head free_g_list; /* tmp list used when freeing this mark */
+ void (*free_mark)(struct fsnotify_mark_entry *entry); /* called on final put+free */
+};
+
+#ifdef CONFIG_FSNOTIFY
+
+/* called from the vfs helpers */
+
+/* main fsnotify call to send events */
+extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+ const char *name, u32 cookie);
+extern void __fsnotify_parent(struct dentry *dentry, __u32 mask);
+extern void __fsnotify_inode_delete(struct inode *inode);
+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(&dcache_lock);
+ assert_spin_locked(&dentry->d_lock);
+
+ parent = dentry->d_parent;
+ if (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
+ * Called with dcache_lock held.
+ */
+static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (!inode)
+ return;
+
+ assert_spin_locked(&dcache_lock);
+
+ spin_lock(&dentry->d_lock);
+ __fsnotify_update_dcache_flags(dentry);
+ spin_unlock(&dentry->d_lock);
+}
+
+/* called from fsnotify listeners, such as fanotify or dnotify */
+
+/* must call when a group changes its ->mask */
+extern void fsnotify_recalc_global_mask(void);
+/* get a reference to an existing or create a new group */
+extern struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num,
+ __u32 mask,
+ const struct fsnotify_ops *ops);
+/* run all marks associated with this group and update group->mask */
+extern void fsnotify_recalc_group_mask(struct fsnotify_group *group);
+/* drop reference on a group from fsnotify_obtain_group */
+extern void fsnotify_put_group(struct fsnotify_group *group);
+
+/* take a reference to an event */
+extern void fsnotify_get_event(struct fsnotify_event *event);
+extern void fsnotify_put_event(struct fsnotify_event *event);
+/* find private data previously attached to an event and unlink it */
+extern struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnotify_group *group,
+ struct fsnotify_event *event);
+
+/* attach the event to the group notification queue */
+extern int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event,
+ struct fsnotify_event_private_data *priv);
+/* 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_notify_event(struct fsnotify_group *group);
+/* return AND dequeue the first event on the notification queue */
+extern struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group);
+
+/* functions used to manipulate the marks attached to inodes */
+
+/* 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_entry *entry, void (*free_mark)(struct fsnotify_mark_entry *entry));
+/* find (and take a reference) to a mark associated with group and inode */
+extern struct fsnotify_mark_entry *fsnotify_find_mark_entry(struct fsnotify_group *group, struct inode *inode);
+/* attach the mark to both the group and the inode */
+extern int fsnotify_add_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group, struct inode *inode);
+/* given a mark, flag it to be freed when all references are dropped */
+extern void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry);
+/* 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_entry *entry);
+extern void fsnotify_put_mark(struct fsnotify_mark_entry *entry);
+extern void fsnotify_unmount_inodes(struct list_head *list);
+
+/* put here because inotify does some weird stuff when destroying watches */
+extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
+ void *data, int data_is, const char *name,
+ u32 cookie);
+
+#else
+
+static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+ const char *name, u32 cookie)
+{}
+
+static inline void __fsnotify_parent(struct dentry *dentry, __u32 mask)
+{}
+
+static inline void __fsnotify_inode_delete(struct inode *inode)
+{}
+
+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 */