fsnotify: create helper fsnotify_update_sb_watchers()

We would like to count watched objects by priority group, so we will need
to update the watched object counter after adding/removing marks.

Create a helper fsnotify_update_sb_watchers() and call it after
attaching/detaching a mark, instead of fsnotify_{get,put}_sb_watchers()
only after attaching/detaching a connector.

Soon, we will use this helper to count watched objects by the highest
watching priority group.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240317184154.1200192-7-amir73il@gmail.com>
This commit is contained in:
Amir Goldstein 2024-03-17 20:41:50 +02:00 committed by Jan Kara
parent 687c217c6a
commit c9d4603b05
2 changed files with 23 additions and 14 deletions

View File

@ -154,20 +154,23 @@ static void fsnotify_put_inode_ref(struct inode *inode)
iput(inode);
}
static void fsnotify_get_sb_watchers(struct fsnotify_mark_connector *conn)
/*
* Grab or drop watched objects reference depending on whether the connector
* is attached and has any marks attached.
*/
static void fsnotify_update_sb_watchers(struct super_block *sb,
struct fsnotify_mark_connector *conn)
{
struct super_block *sb = fsnotify_connector_sb(conn);
bool is_watched = conn->flags & FSNOTIFY_CONN_FLAG_IS_WATCHED;
bool has_marks = conn->obj && !hlist_empty(&conn->list);
if (sb)
if (has_marks && !is_watched) {
conn->flags |= FSNOTIFY_CONN_FLAG_IS_WATCHED;
fsnotify_get_sb_watched_objects(sb);
}
static void fsnotify_put_sb_watchers(struct fsnotify_mark_connector *conn)
{
struct super_block *sb = fsnotify_connector_sb(conn);
if (sb)
} else if (!has_marks && is_watched) {
conn->flags &= ~FSNOTIFY_CONN_FLAG_IS_WATCHED;
fsnotify_put_sb_watched_objects(sb);
}
}
/*
@ -266,6 +269,7 @@ static void *fsnotify_detach_connector_from_object(
unsigned int *type)
{
fsnotify_connp_t *connp = fsnotify_object_connp(conn->obj, conn->type);
struct super_block *sb = fsnotify_connector_sb(conn);
struct inode *inode = NULL;
*type = conn->type;
@ -285,10 +289,10 @@ static void *fsnotify_detach_connector_from_object(
fsnotify_conn_sb(conn)->s_fsnotify_mask = 0;
}
fsnotify_put_sb_watchers(conn);
rcu_assign_pointer(*connp, NULL);
conn->obj = NULL;
conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
fsnotify_update_sb_watchers(sb, conn);
return inode;
}
@ -340,6 +344,11 @@ void fsnotify_put_mark(struct fsnotify_mark *mark)
objp = fsnotify_detach_connector_from_object(conn, &type);
free_conn = true;
} else {
struct super_block *sb = fsnotify_connector_sb(conn);
/* Update watched objects after detaching mark */
if (sb)
fsnotify_update_sb_watchers(sb, conn);
objp = __fsnotify_recalc_mask(conn);
type = conn->type;
}
@ -581,10 +590,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp,
if (cmpxchg(connp, NULL, conn)) {
/* Someone else created list structure for us */
kmem_cache_free(fsnotify_mark_connector_cachep, conn);
return 0;
}
fsnotify_get_sb_watchers(conn);
return 0;
}
@ -624,6 +630,7 @@ out:
static int fsnotify_add_mark_list(struct fsnotify_mark *mark, void *obj,
unsigned int obj_type, int add_flags)
{
struct super_block *sb = fsnotify_object_sb(obj, obj_type);
struct fsnotify_mark *lmark, *last = NULL;
struct fsnotify_mark_connector *conn;
fsnotify_connp_t *connp;
@ -673,6 +680,7 @@ restart:
/* mark should be the last entry. last is the current last entry */
hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
added:
fsnotify_update_sb_watchers(sb, conn);
/*
* Since connector is attached to object using cmpxchg() we are
* guaranteed that connector initialization is fully visible by anyone

View File

@ -465,6 +465,7 @@ FSNOTIFY_ITER_FUNCS(sb, SB)
struct fsnotify_mark_connector {
spinlock_t lock;
unsigned short type; /* Type of object [lock] */
#define FSNOTIFY_CONN_FLAG_IS_WATCHED 0x01
#define FSNOTIFY_CONN_FLAG_HAS_IREF 0x02
unsigned short flags; /* flags [lock] */
union {