Similar to events "on child" to watching directory, send event flavor
"on child" to sb/mount marks that specified interest in this flavor.
Event "on child" will not be sent on "orphan" children, that is, on
disconnected dentries and on a mount/sb root.
Currently, fanotify allows to set the FAN_EVENT_ON_CHILD flag on
sb/mount marks, but it was ignored. Mask the flag explicitly until
fanotify implements support for events "on child" with name info
for sb/mount marks.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 7 ++++--
fs/notify/fsnotify.c | 38 ++++++++++++++++++++++++------
include/linux/fsnotify_backend.h | 23 ++++++++++++------
3 files changed, 52 insertions(+), 16 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 030534da49e2..36c1327b32f4 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1146,10 +1146,13 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
}
/* inode held in place by reference to path; group by fget on fd */
- if (mark_type == FAN_MARK_INODE)
+ if (mark_type == FAN_MARK_INODE) {
inode = path.dentry->d_inode;
- else
+ } else {
mnt = path.mnt;
+ /* Mask out FAN_EVENT_ON_CHILD flag for sb/mount marks */
+ mask &= ~FAN_EVENT_ON_CHILD;
+ }
/* create/update an inode mark */
switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 72d332ce8e12..f6da8f263bc0 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -142,23 +142,50 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
spin_unlock(&inode->i_lock);
}
-/* Notify this dentry's parent about a child's events. */
+/*
+ * Notify this dentry's parent about a child's events if parent is watching
+ * children or if sb/mount marks are interested in events with file_name info.
+ */
int fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
int data_type)
{
+ const struct path *path = fsnotify_data_path(data, data_type);
+ struct mount *mnt = NULL;
+ bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED;
+ __u32 test_mask = mask & FS_EVENTS_POSS_ON_CHILD;
+ __u32 p_mask, marks_mask = 0;
struct dentry *parent;
struct inode *p_inode;
int ret = 0;
- if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
+ if (path && path->mnt->mnt_root != dentry)
+ mnt = real_mount(path->mnt);
+
+ /*
+ * FS_EVENT_ON_CHILD on sb/mount mask implies reporting events as if all
+ * directories are watched.
+ */
+ if (!IS_ROOT(dentry))
+ marks_mask |= fsnotify_watches_children(
+ dentry->d_sb->s_fsnotify_mask);
+ if (mnt)
+ marks_mask |= fsnotify_watches_children(
+ mnt->mnt_fsnotify_mask);
+
+
+ if (!(marks_mask & test_mask) && !parent_watched)
return 0;
parent = dget_parent(dentry);
p_inode = parent->d_inode;
+ p_mask = fsnotify_inode_watches_children(p_inode);
- if (unlikely(!fsnotify_inode_watches_children(p_inode))) {
+ if (p_mask)
+ marks_mask |= p_mask;
+ else if (unlikely(parent_watched))
__fsnotify_update_child_dentry_flags(p_inode);
- } else if (p_inode->i_fsnotify_mask & mask & ALL_FSNOTIFY_EVENTS) {
+
+ if (marks_mask & test_mask) {
struct name_snapshot name;
/* we are notifying a parent so come up with the new mask which
@@ -323,9 +350,6 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
mnt = real_mount(path->mnt);
mnt_or_sb_mask |= mnt->mnt_fsnotify_mask;
}
- /* An event "on child" is not intended for a mount/sb mark */
- if (mask & FS_EVENT_ON_CHILD)
- mnt_or_sb_mask = 0;
/*
* Optimization: srcu_read_lock() has a memory barrier which can
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index f0c506405b54..ca461b95662a 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -50,8 +50,12 @@
#define FS_DIR_MODIFY 0x00080000 /* Directory entry was modified */
#define FS_EXCL_UNLINK 0x04000000 /* do not send events if object is unlinked */
-/* This inode cares about things that happen to its children. Always set for
- * dnotify and inotify. */
+/*
+ * This inode cares about things that happen to its children.
+ * Always set for dnotify and inotify.
+ * Set on sb/mount marks mask to indicate interest in getting events with
+ * file_name information.
+ */
#define FS_EVENT_ON_CHILD 0x08000000
#define FS_DN_RENAME 0x10000000 /* file renamed */
@@ -386,14 +390,19 @@ extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
extern void fsnotify_sb_delete(struct super_block *sb);
extern u32 fsnotify_get_cookie(void);
-static inline int fsnotify_inode_watches_children(struct inode *inode)
+static inline __u32 fsnotify_watches_children(__u32 mask)
{
- /* FS_EVENT_ON_CHILD is set if the inode may care */
- if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
+ /* FS_EVENT_ON_CHILD is set if the object may care */
+ if (!(mask & FS_EVENT_ON_CHILD))
return 0;
- /* this inode might care about child events, does it care about the
+ /* This object 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;
+ return mask & FS_EVENTS_POSS_ON_CHILD;
+}
+
+static inline int fsnotify_inode_watches_children(struct inode *inode)
+{
+ return fsnotify_watches_children(inode->i_fsnotify_mask);
}
/*
--
2.17.1
