fanotify: should_send_event needs to handle vfsmounts

currently should_send_event in fanotify only cares about marks on inodes.
This patch extends that interface to indicate that it cares about events
that happened on vfsmounts.

Signed-off-by: Eric Paris <eparis@redhat.com>

2 files changed, 47 insertions, 11 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index aa5e92661142..202be8adb2ec 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -2,6 +2,7 @@
 #include <linux/fsnotify_backend.h>
 #include <linux/init.h>
 #include <linux/kernel.h> /* UINT_MAX */
+#include <linux/mount.h>
 #include <linux/types.h>
 
 #include "fanotify.h"
@@ -99,24 +100,35 @@ static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_e
         return ret;
 }
 
-static bool fanotify_should_send_event(struct fsnotify_group *group, struct inode *inode,
-                                       struct vfsmount *mnt, __u32 mask, void *data,
-                                       int data_type)
+static bool should_send_vfsmount_event(struct fsnotify_group *group, struct vfsmount *mnt,
+                                       __u32 mask)
 {
         struct fsnotify_mark *fsn_mark;
         bool send;
 
-        pr_debug("%s: group=%p inode=%p mask=%x data=%p data_type=%d\n",
-                 __func__, group, inode, mask, data, data_type);
+        pr_debug("%s: group=%p vfsmount=%p mask=%x\n",
+                 __func__, group, mnt, mask);
 
-        /* sorry, fanotify only gives a damn about files and dirs */
-        if (!S_ISREG(inode->i_mode) &&
-            !S_ISDIR(inode->i_mode))
+        fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
+        if (!fsn_mark)
                 return false;
 
-        /* if we don't have enough info to send an event to userspace say no */
-        if (data_type != FSNOTIFY_EVENT_PATH)
-                return false;
+        send = (mask & fsn_mark->mask);
+
+        /* find took a reference */
+        fsnotify_put_mark(fsn_mark);
+
+        return send;
+}
+
+static bool should_send_inode_event(struct fsnotify_group *group, struct inode *inode,
+                                    __u32 mask)
+{
+        struct fsnotify_mark *fsn_mark;
+        bool send;
+
+        pr_debug("%s: group=%p inode=%p mask=%x\n",
+                 __func__, group, inode, mask);
 
         fsn_mark = fsnotify_find_inode_mark(group, inode);
         if (!fsn_mark)
@@ -142,6 +154,28 @@ static bool fanotify_should_send_event(struct fsnotify_group *group, struct inod
         return send;
 }
 
+static bool fanotify_should_send_event(struct fsnotify_group *group, struct inode *to_tell,
+                                       struct vfsmount *mnt, __u32 mask, void *data,
+                                       int data_type)
+{
+        pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x data=%p data_type=%d\n",
+                 __func__, group, to_tell, mnt, mask, data, data_type);
+
+        /* sorry, fanotify only gives a damn about files and dirs */
+        if (!S_ISREG(to_tell->i_mode) &&
+            !S_ISDIR(to_tell->i_mode))
+                return false;
+
+        /* if we don't have enough info to send an event to userspace say no */
+        if (data_type != FSNOTIFY_EVENT_PATH)
+                return false;
+
+        if (mnt)
+                return should_send_vfsmount_event(group, mnt, mask);
+        else
+                return should_send_inode_event(group, to_tell, mask);
+}
+
 const struct fsnotify_ops fanotify_fsnotify_ops = {
         .handle_event = fanotify_handle_event,
         .should_send_event = fanotify_should_send_event,
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 1af42cbfc429..2d2f015fb700 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -368,6 +368,8 @@ extern void fsnotify_recalc_inode_mask(struct inode *inode);
 extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(struct fsnotify_mark *mark));
 /* find (and take a reference) to a mark associated with group and inode */
 extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode);
+/* find (and take a reference) to a mark associated with group and vfsmount */
+extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt);
 /* copy the values from old into new */
 extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old);
 /* attach the mark to both the group and the inode */