This patch introduces fsnotify_remove_mark() which is the counterpart to
fsnotify_add_mark().
The implementation is equal to that of fsnotify_destroy_mark() with the difference
that the group is passed as a function argument and the group lock is taken first.
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
---
fs/notify/mark.c | 74 ++++++++++++++++++++++++++++++++++++++
include/linux/fsnotify_backend.h | 3 ++
2 files changed, 77 insertions(+), 0 deletions(-)
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 1ac0447..3b00203 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -262,6 +262,80 @@ err:
}
/*
+ * Remove a mark from a given group and the fsobject.
+ * Must not be called for a mark that is not on the groups mark list.
+ */
+void fsnotify_remove_mark(struct fsnotify_mark *mark,
+ struct fsnotify_group *group)
+{
+ struct inode *inode = NULL;
+
+ spin_lock(&group->mark_lock);
+ spin_lock(&mark->lock);
+
+ /* something else already called this function on this mark */
+ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
+ spin_unlock(&mark->lock);
+ spin_unlock(&group->mark_lock);
+ return;
+ }
+
+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
+
+ /* 1 from caller and 1 for being on i_list/g_list */
+ BUG_ON(atomic_read(&mark->refcnt) < 2);
+
+
+ if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
+ inode = mark->i.inode;
+ fsnotify_destroy_inode_mark(mark);
+ } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT)
+ fsnotify_destroy_vfsmount_mark(mark);
+ else
+ BUG();
+ spin_unlock(&mark->lock);
+
+ list_del_init(&mark->g_list);
+ spin_unlock(&group->mark_lock);
+
+ spin_lock(&destroy_lock);
+ list_add(&mark->destroy_list, &destroy_list);
+ spin_unlock(&destroy_lock);
+ wake_up(&destroy_waitq);
+
+ /*
+ * Some groups like to know that marks are being freed. This is a
+ * callback to the group function to let it know that this mark
+ * is being freed.
+ */
+ if (group->ops->freeing_mark)
+ group->ops->freeing_mark(mark, group);
+
+ /*
+ * __fsnotify_update_child_dentry_flags(inode);
+ *
+ * I really want to call that, but we can't, we have no idea if the inode
+ * still exists the second we drop the mark->lock.
+ *
+ * The next time an event arrive to this inode from one of it's children
+ * __fsnotify_parent will see that the inode doesn't care about it's
+ * children and will update all of these flags then. So really this
+ * is just a lazy update (and could be a perf win...)
+ */
+
+ if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED))
+ iput(inode);
+
+ /*
+ * it's possible that this group tried to destroy itself, but this
+ * this mark was simultaneously being freed by inode. If that's the
+ * case, we finish freeing the group here.
+ */
+ if (unlikely(atomic_dec_and_test(&group->num_marks)))
+ fsnotify_final_destroy_group(group);
+}
+
+/*
* clear any marks in a group in which mark->flags & flags is true
*/
void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group,
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 6a3c660..c7bfee6 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -404,6 +404,9 @@ 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);
+/* remove a mark from a given group and fsobject */
+extern void fsnotify_remove_mark(struct fsnotify_mark *mark,
+ struct fsnotify_group *group);
/* given a mark, flag it to be freed when all references are dropped */
extern void fsnotify_destroy_mark(struct fsnotify_mark *mark);
/* run all the marks in a group, and clear all of the vfsmount marks */
--
1.5.6.5
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