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fsnotify: parent event notification

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inotify and dnotify both use a similar parent notification mechanism.  We
add a generic parent notification mechanism to fsnotify for both of these
to use.  This new machanism also adds the dentry flag optimization which
exists for inotify to dnotify.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Eric Paris
2009-05-21 17:01:29 -04:00
parent 3be25f49b9
commit c28f7e56e9
6 changed files with 205 additions and 10 deletions
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64
include/linux/fsnotify_backend.h
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@@ -46,6 +46,17 @@
#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)
struct fsnotify_group;
struct fsnotify_event;
struct fsnotify_mark_entry;
@@ -183,8 +194,52 @@ struct fsnotify_mark_entry {
/* main fsnotify call to send events */
extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is);
extern void __fsnotify_parent(struct dentry *dentry, __u32 mask);
extern void __fsnotify_inode_delete(struct inode *inode);
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 */
@@ -230,9 +285,18 @@ extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32
static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
{}
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)
{}
#endif /* CONFIG_FSNOTIFY */
#endif /* __KERNEL __ */