fsnotify: remove mark->free_list

Free list is used when all marks on given inode / mount should be
destroyed when inode / mount is going away.  However we can free all of
the marks without using a special list with some care.

Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index d675e76..db39de2 100644 (file)
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -26,7 +26,6 @@
 
 #include <linux/fsnotify_backend.h>
 #include "fsnotify.h"
-#include "../mount.h"
 
 /*
  * Clear all of the marks on an inode when it is being evicted from core

diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index 13a00be..b44c68a 100644 (file)
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -6,6 +6,8 @@
 #include <linux/srcu.h>
 #include <linux/types.h>
 
+#include "../mount.h"
+
 /* destroy all events sitting in this groups notification queue */
 extern void fsnotify_flush_notify(struct fsnotify_group *group);
 
@@ -38,15 +40,22 @@ extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
 extern void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark);
 /* inode specific destruction of a mark */
 extern void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark);
-/* Destroy all marks in the given list */
-extern void fsnotify_destroy_marks(struct list_head *to_free);
 /* Find mark belonging to given group in the list of marks */
 extern struct fsnotify_mark *fsnotify_find_mark(struct hlist_head *head,
                                                struct fsnotify_group *group);
-/* run the list of all marks associated with inode and flag them to be freed */
-extern void fsnotify_clear_marks_by_inode(struct inode *inode);
-/* run the list of all marks associated with vfsmount and flag them to be freed */
-extern void fsnotify_clear_marks_by_mount(struct vfsmount *mnt);
+/* Destroy all marks in the given list protected by 'lock' */
+extern void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock);
+/* run the list of all marks associated with inode and destroy them */
+static inline void fsnotify_clear_marks_by_inode(struct inode *inode)
+{
+       fsnotify_destroy_marks(&inode->i_fsnotify_marks, &inode->i_lock);
+}
+/* run the list of all marks associated with vfsmount and destroy them */
+static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
+{
+       fsnotify_destroy_marks(&real_mount(mnt)->mnt_fsnotify_marks,
+                              &mnt->mnt_root->d_lock);
+}
 /*
  * update the dentry->d_flags of all of inode's children to indicate if inode cares
  * about events that happen to its children.

diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 3daf513..474a3ce 100644 (file)
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -65,26 +65,6 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
 }
 
 /*
- * Given an inode, destroy all of the marks associated with that inode.
- */
-void fsnotify_clear_marks_by_inode(struct inode *inode)
-{
-       struct fsnotify_mark *mark;
-       struct hlist_node *n;
-       LIST_HEAD(free_list);
-
-       spin_lock(&inode->i_lock);
-       hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, obj_list) {
-               list_add(&mark->free_list, &free_list);
-               hlist_del_init_rcu(&mark->obj_list);
-               fsnotify_get_mark(mark);
-       }
-       spin_unlock(&inode->i_lock);
-
-       fsnotify_destroy_marks(&free_list);
-}
-
-/*
  * Given a group clear all of the inode marks associated with that group.
  */
 void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 39ddcaf..3b2d1ba 100644 (file)
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -203,24 +203,34 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark,
        mutex_unlock(&group->mark_mutex);
 }
 
-/*
- * Destroy all marks in the given list. The marks must be already detached from
- * the original inode / vfsmount.
- */
-void fsnotify_destroy_marks(struct list_head *to_free)
+void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock)
 {
-       struct fsnotify_mark *mark, *lmark;
-       struct fsnotify_group *group;
-
-       list_for_each_entry_safe(mark, lmark, to_free, free_list) {
-               spin_lock(&mark->lock);
-               fsnotify_get_group(mark->group);
-               group = mark->group;
-               spin_unlock(&mark->lock);
+       struct fsnotify_mark *mark;
 
-               fsnotify_destroy_mark(mark, group);
+       while (1) {
+               /*
+                * We have to be careful since we can race with e.g.
+                * fsnotify_clear_marks_by_group() and once we drop 'lock',
+                * mark can get removed from the obj_list and destroyed. But
+                * we are holding mark reference so mark cannot be freed and
+                * calling fsnotify_destroy_mark() more than once is fine.
+                */
+               spin_lock(lock);
+               if (hlist_empty(head)) {
+                       spin_unlock(lock);
+                       break;
+               }
+               mark = hlist_entry(head->first, struct fsnotify_mark, obj_list);
+               /*
+                * We don't update i_fsnotify_mask / mnt_fsnotify_mask here
+                * since inode / mount is going away anyway. So just remove
+                * mark from the list.
+                */
+               hlist_del_init_rcu(&mark->obj_list);
+               fsnotify_get_mark(mark);
+               spin_unlock(lock);
+               fsnotify_destroy_mark(mark, mark->group);
                fsnotify_put_mark(mark);
-               fsnotify_put_group(group);
        }
 }
 

diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c
index 326b148..a8fcab6 100644 (file)
--- a/fs/notify/vfsmount_mark.c
+++ b/fs/notify/vfsmount_mark.c
@@ -28,25 +28,6 @@
 
 #include <linux/fsnotify_backend.h>
 #include "fsnotify.h"
-#include "../mount.h"
-
-void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
-{
-       struct fsnotify_mark *mark;
-       struct hlist_node *n;
-       struct mount *m = real_mount(mnt);
-       LIST_HEAD(free_list);
-
-       spin_lock(&mnt->mnt_root->d_lock);
-       hlist_for_each_entry_safe(mark, n, &m->mnt_fsnotify_marks, obj_list) {
-               list_add(&mark->free_list, &free_list);
-               hlist_del_init_rcu(&mark->obj_list);
-               fsnotify_get_mark(mark);
-       }
-       spin_unlock(&mnt->mnt_root->d_lock);
-
-       fsnotify_destroy_marks(&free_list);
-}
 
 void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
 {

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index dd6ddb0..f044fe3 100644 (file)
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -225,8 +225,6 @@ struct fsnotify_mark {
        spinlock_t lock;
        /* List of marks for inode / vfsmount [obj_lock] */
        struct hlist_node obj_list;
-       /* tmp list used when freeing this mark */
-       struct list_head free_list;
        union { /* Object pointer [mark->lock, group->mark_mutex] */
                struct inode *inode;    /* inode this mark is associated with */
                struct vfsmount *mnt;   /* vfsmount this mark is associated with */