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authorJoel Becker <joel.becker@oracle.com>2006-10-06 17:33:23 -0700
committerMark Fasheh <mark.fasheh@oracle.com>2007-07-10 17:11:01 -0700
commit299894cc9001b09e3e9685f2709b49e7e1092ccc (patch)
tree2a2e9bb69d2393bf620a34daea17e52ed9f9e5d7 /Documentation/filesystems/configfs/configfs.txt
parent6d748924b753d63a57dad130fdf11f64c27ff54b (diff)
configfs: accessing item hierarchy during rmdir(2)
Add a notification callback, ops->disconnect_notify(). It has the same prototype as ->drop_item(), but it will be called just before the item linkage is broken. This way, configfs users who want to do work while the object is still in the heirarchy have a chance. Client drivers will still need to config_item_put() in their ->drop_item(), if they implement it. They need do nothing in ->disconnect_notify(). They don't have to provide it if they don't care. But someone who wants to be notified before ci_parent is set to NULL can now be notified. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to 'Documentation/filesystems/configfs/configfs.txt')
-rw-r--r--Documentation/filesystems/configfs/configfs.txt12
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt
index 21f038e6672..aef74cdecc2 100644
--- a/Documentation/filesystems/configfs/configfs.txt
+++ b/Documentation/filesystems/configfs/configfs.txt
@@ -238,6 +238,8 @@ config_item_type.
struct config_group *(*make_group)(struct config_group *group,
const char *name);
int (*commit_item)(struct config_item *item);
+ void (*disconnect_notify)(struct config_group *group,
+ struct config_item *item);
void (*drop_item)(struct config_group *group,
struct config_item *item);
};
@@ -268,6 +270,16 @@ the item in other threads, the memory is safe. It may take some time
for the item to actually disappear from the subsystem's usage. But it
is gone from configfs.
+When drop_item() is called, the item's linkage has already been torn
+down. It no longer has a reference on its parent and has no place in
+the item hierarchy. If a client needs to do some cleanup before this
+teardown happens, the subsystem can implement the
+ct_group_ops->disconnect_notify() method. The method is called after
+configfs has removed the item from the filesystem view but before the
+item is removed from its parent group. Like drop_item(),
+disconnect_notify() is void and cannot fail. Client subsystems should
+not drop any references here, as they still must do it in drop_item().
+
A config_group cannot be removed while it still has child items. This
is implemented in the configfs rmdir(2) code. ->drop_item() will not be
called, as the item has not been dropped. rmdir(2) will fail, as the