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-rw-r--r--fs/notify/fsnotify.c36
-rw-r--r--fs/notify/fsnotify.h4
-rw-r--r--fs/notify/inode_mark.c8
-rw-r--r--fs/notify/mark.c36
-rw-r--r--fs/notify/vfsmount_mark.c8
5 files changed, 67 insertions, 25 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 9d3e9c50066a..89326acd4561 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -229,8 +229,16 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
&fsnotify_mark_srcu);
}
+ /*
+ * We need to merge inode & vfsmount mark lists so that inode mark
+ * ignore masks are properly reflected for mount mark notifications.
+ * That's why this traversal is so complicated...
+ */
while (inode_node || vfsmount_node) {
- inode_group = vfsmount_group = NULL;
+ inode_group = NULL;
+ inode_mark = NULL;
+ vfsmount_group = NULL;
+ vfsmount_mark = NULL;
if (inode_node) {
inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
@@ -244,21 +252,19 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
vfsmount_group = vfsmount_mark->group;
}
- if (inode_group > vfsmount_group) {
- /* handle inode */
- ret = send_to_group(to_tell, inode_mark, NULL, mask,
- data, data_is, cookie, file_name);
- /* we didn't use the vfsmount_mark */
- vfsmount_group = NULL;
- } else if (vfsmount_group > inode_group) {
- ret = send_to_group(to_tell, NULL, vfsmount_mark, mask,
- data, data_is, cookie, file_name);
- inode_group = NULL;
- } else {
- ret = send_to_group(to_tell, inode_mark, vfsmount_mark,
- mask, data, data_is, cookie,
- file_name);
+ if (inode_group && vfsmount_group) {
+ int cmp = fsnotify_compare_groups(inode_group,
+ vfsmount_group);
+ if (cmp > 0) {
+ inode_group = NULL;
+ inode_mark = NULL;
+ } else if (cmp < 0) {
+ vfsmount_group = NULL;
+ vfsmount_mark = NULL;
+ }
}
+ ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask,
+ data, data_is, cookie, file_name);
if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
goto out;
diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index 9c0898c4cfe1..3b68b0ae0a97 100644
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -12,6 +12,10 @@ extern void fsnotify_flush_notify(struct fsnotify_group *group);
/* protects reads of inode and vfsmount marks list */
extern struct srcu_struct fsnotify_mark_srcu;
+/* compare two groups for sorting of marks lists */
+extern int fsnotify_compare_groups(struct fsnotify_group *a,
+ struct fsnotify_group *b);
+
extern void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *fsn_mark,
__u32 mask);
/* add a mark to an inode */
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index e8497144b323..dfbf5447eea4 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -194,6 +194,7 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
{
struct fsnotify_mark *lmark, *last = NULL;
int ret = 0;
+ int cmp;
mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
@@ -219,11 +220,8 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
goto out;
}
- if (mark->group->priority < lmark->group->priority)
- continue;
-
- if ((mark->group->priority == lmark->group->priority) &&
- (mark->group < lmark->group))
+ cmp = fsnotify_compare_groups(lmark->group, mark->group);
+ if (cmp < 0)
continue;
hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list);
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index d90deaa08e78..34c38fabf514 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -210,6 +210,42 @@ void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mas
}
/*
+ * Sorting function for lists of fsnotify marks.
+ *
+ * Fanotify supports different notification classes (reflected as priority of
+ * notification group). Events shall be passed to notification groups in
+ * decreasing priority order. To achieve this marks in notification lists for
+ * inodes and vfsmounts are sorted so that priorities of corresponding groups
+ * are descending.
+ *
+ * Furthermore correct handling of the ignore mask requires processing inode
+ * and vfsmount marks of each group together. Using the group address as
+ * further sort criterion provides a unique sorting order and thus we can
+ * merge inode and vfsmount lists of marks in linear time and find groups
+ * present in both lists.
+ *
+ * A return value of 1 signifies that b has priority over a.
+ * A return value of 0 signifies that the two marks have to be handled together.
+ * A return value of -1 signifies that a has priority over b.
+ */
+int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
+{
+ if (a == b)
+ return 0;
+ if (!a)
+ return 1;
+ if (!b)
+ return -1;
+ if (a->priority < b->priority)
+ return 1;
+ if (a->priority > b->priority)
+ return -1;
+ if (a < b)
+ return 1;
+ return -1;
+}
+
+/*
* Attach an initialized mark to a given group and fs object.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which group.
diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c
index ac851e8376b1..faefa72a11eb 100644
--- a/fs/notify/vfsmount_mark.c
+++ b/fs/notify/vfsmount_mark.c
@@ -153,6 +153,7 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
struct mount *m = real_mount(mnt);
struct fsnotify_mark *lmark, *last = NULL;
int ret = 0;
+ int cmp;
mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
@@ -178,11 +179,8 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
goto out;
}
- if (mark->group->priority < lmark->group->priority)
- continue;
-
- if ((mark->group->priority == lmark->group->priority) &&
- (mark->group < lmark->group))
+ cmp = fsnotify_compare_groups(lmark->group, mark->group);
+ if (cmp < 0)
continue;
hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);