fsnotify: let connector point to an abstract object

Make the code to attach/detach a connector to object more generic
by letting the fsnotify connector point to an abstract fsnotify_connp_t.
Code that needs to dereference an inode or mount object now uses the
helpers fsnotify_conn_{inode,mount}.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/notify/fdinfo.c b/fs/notify/fdinfo.c
index 10aac19..86fcf58 100644 (file)
--- a/fs/notify/fdinfo.c
+++ b/fs/notify/fdinfo.c
@@ -15,7 +15,7 @@
 #include <linux/exportfs.h>
 
 #include "inotify/inotify.h"
-#include "../fs/mount.h"
+#include "fsnotify.h"
 
 #if defined(CONFIG_PROC_FS)
 
@@ -81,7 +81,7 @@ static void inotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark)
                return;
 
        inode_mark = container_of(mark, struct inotify_inode_mark, fsn_mark);
-       inode = igrab(mark->connector->inode);
+       inode = igrab(fsnotify_conn_inode(mark->connector));
        if (inode) {
                /*
                 * IN_ALL_EVENTS represents all of the mask bits
@@ -117,7 +117,7 @@ static void fanotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark)
                mflags |= FAN_MARK_IGNORED_SURV_MODIFY;
 
        if (mark->connector->type == FSNOTIFY_OBJ_TYPE_INODE) {
-               inode = igrab(mark->connector->inode);
+               inode = igrab(fsnotify_conn_inode(mark->connector));
                if (!inode)
                        return;
                seq_printf(m, "fanotify ino:%lx sdev:%x mflags:%x mask:%x ignored_mask:%x ",
@@ -127,7 +127,7 @@ static void fanotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark)
                seq_putc(m, '\n');
                iput(inode);
        } else if (mark->connector->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT) {
-               struct mount *mnt = real_mount(mark->connector->mnt);
+               struct mount *mnt = fsnotify_conn_mount(mark->connector);
 
                seq_printf(m, "fanotify mnt_id:%x mflags:%x mask:%x ignored_mask:%x\n",
                           mnt->mnt_id, mflags, mark->mask, mark->ignored_mask);

diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index caeee04..7902653 100644 (file)
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -9,14 +9,16 @@
 
 #include "../mount.h"
 
-static inline struct inode *fsnotify_obj_inode(fsnotify_connp_t *connp)
+static inline struct inode *fsnotify_conn_inode(
+                               struct fsnotify_mark_connector *conn)
 {
-       return container_of(connp, struct inode, i_fsnotify_marks);
+       return container_of(conn->obj, struct inode, i_fsnotify_marks);
 }
 
-static inline struct mount *fsnotify_obj_mount(fsnotify_connp_t *connp)
+static inline struct mount *fsnotify_conn_mount(
+                               struct fsnotify_mark_connector *conn)
 {
-       return container_of(connp, struct mount, mnt_fsnotify_marks);
+       return container_of(conn->obj, struct mount, mnt_fsnotify_marks);
 }
 
 /* destroy all events sitting in this groups notification queue */

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 7abb73b..959bc73 100644 (file)
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -120,14 +120,14 @@ static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
                        new_mask |= mark->mask;
        }
        if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
-               conn->inode->i_fsnotify_mask = new_mask;
+               fsnotify_conn_inode(conn)->i_fsnotify_mask = new_mask;
        else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT)
-               real_mount(conn->mnt)->mnt_fsnotify_mask = new_mask;
+               fsnotify_conn_mount(conn)->mnt_fsnotify_mask = new_mask;
 }
 
 /*
  * Calculate mask of events for a list of marks. The caller must make sure
- * connector and connector->inode cannot disappear under us.  Callers achieve
+ * connector and connector->obj cannot disappear under us.  Callers achieve
  * this by holding a mark->lock or mark->group->mark_mutex for a mark on this
  * list.
  */
@@ -140,7 +140,8 @@ void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
        __fsnotify_recalc_mask(conn);
        spin_unlock(&conn->lock);
        if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
-               __fsnotify_update_child_dentry_flags(conn->inode);
+               __fsnotify_update_child_dentry_flags(
+                                       fsnotify_conn_inode(conn));
 }
 
 /* Free all connectors queued for freeing once SRCU period ends */
@@ -166,20 +167,20 @@ static struct inode *fsnotify_detach_connector_from_object(
 {
        struct inode *inode = NULL;
 
+       if (conn->type == FSNOTIFY_OBJ_TYPE_DETACHED)
+               return NULL;
+
        if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) {
-               inode = conn->inode;
-               rcu_assign_pointer(inode->i_fsnotify_marks, NULL);
+               inode = fsnotify_conn_inode(conn);
                inode->i_fsnotify_mask = 0;
-               conn->inode = NULL;
-               conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
        } else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT) {
-               rcu_assign_pointer(real_mount(conn->mnt)->mnt_fsnotify_marks,
-                                  NULL);
-               real_mount(conn->mnt)->mnt_fsnotify_mask = 0;
-               conn->mnt = NULL;
-               conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
+               fsnotify_conn_mount(conn)->mnt_fsnotify_mask = 0;
        }
 
+       rcu_assign_pointer(*(conn->obj), NULL);
+       conn->obj = NULL;
+       conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
+
        return inode;
 }
 
@@ -448,10 +449,9 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp,
        spin_lock_init(&conn->lock);
        INIT_HLIST_HEAD(&conn->list);
        conn->type = type;
+       conn->obj = connp;
        if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
-               inode = conn->inode = igrab(fsnotify_obj_inode(connp));
-       else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT)
-               conn->mnt = &fsnotify_obj_mount(connp)->mnt;
+               inode = igrab(fsnotify_conn_inode(conn));
        /*
         * cmpxchg() provides the barrier so that readers of *connp can see
         * only initialized structure

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 8efb866..381cfb0 100644 (file)
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -256,6 +256,13 @@ FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)
        for (type = 0; type < FSNOTIFY_OBJ_TYPE_COUNT; type++)
 
 /*
+ * fsnotify_connp_t is what we embed in objects which connector can be attached
+ * to. fsnotify_connp_t * is how we refer from connector back to object.
+ */
+struct fsnotify_mark_connector;
+typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
+
+/*
  * Inode / vfsmount point to this structure which tracks all marks attached to
  * the inode / vfsmount. The reference to inode / vfsmount is held by this
  * structure. We destroy this structure when there are no more marks attached
@@ -264,17 +271,15 @@ FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)
 struct fsnotify_mark_connector {
        spinlock_t lock;
        unsigned int type;      /* Type of object [lock] */
-       union { /* Object pointer [lock] */
-               struct inode *inode;
-               struct vfsmount *mnt;
+       union {
+               /* Object pointer [lock] */
+               fsnotify_connp_t *obj;
                /* Used listing heads to free after srcu period expires */
                struct fsnotify_mark_connector *destroy_next;
        };
        struct hlist_head list;
 };
 
-typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
-
 /*
  * A mark is simply an object attached to an in core inode which allows an
  * fsnotify listener to indicate they are either no longer interested in events

diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index c99ebaa..02feef9 100644 (file)
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -168,7 +168,8 @@ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
 /* Function to return search key in our hash from inode. */
 static unsigned long inode_to_key(const struct inode *inode)
 {
-       return (unsigned long)inode;
+       /* Use address pointed to by connector->obj as the key */
+       return (unsigned long)&inode->i_fsnotify_marks;
 }
 
 /*
@@ -183,7 +184,7 @@ static unsigned long chunk_to_key(struct audit_chunk *chunk)
         */
        if (WARN_ON_ONCE(!chunk->mark.connector))
                return 0;
-       return (unsigned long)chunk->mark.connector->inode;
+       return (unsigned long)chunk->mark.connector->obj;
 }
 
 static inline struct list_head *chunk_hash(unsigned long key)
@@ -258,7 +259,7 @@ static void untag_chunk(struct node *p)
        spin_lock(&entry->lock);
        /*
         * mark_mutex protects mark from getting detached and thus also from
-        * mark->connector->inode getting NULL.
+        * mark->connector->obj getting NULL.
         */
        if (chunk->dead || !(entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
                spin_unlock(&entry->lock);
@@ -288,8 +289,8 @@ static void untag_chunk(struct node *p)
        if (!new)
                goto Fallback;
 
-       if (fsnotify_add_inode_mark_locked(&new->mark, entry->connector->inode,
-                                          1)) {
+       if (fsnotify_add_mark_locked(&new->mark, entry->connector->obj,
+                                    FSNOTIFY_OBJ_TYPE_INODE, 1)) {
                fsnotify_put_mark(&new->mark);
                goto Fallback;
        }
@@ -423,7 +424,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
        spin_lock(&old_entry->lock);
        /*
         * mark_mutex protects mark from getting detached and thus also from
-        * mark->connector->inode getting NULL.
+        * mark->connector->obj getting NULL.
         */
        if (!(old_entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
                /* old_entry is being shot, lets just lie */
@@ -434,8 +435,8 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
                return -ENOENT;
        }
 
-       if (fsnotify_add_inode_mark_locked(chunk_entry,
-                            old_entry->connector->inode, 1)) {
+       if (fsnotify_add_mark_locked(chunk_entry, old_entry->connector->obj,
+                                    FSNOTIFY_OBJ_TYPE_INODE, 1)) {
                spin_unlock(&old_entry->lock);
                mutex_unlock(&old_entry->group->mark_mutex);
                fsnotify_put_mark(chunk_entry);