fsnotify: store struct file not struct path

Al explains that calling dentry_open() with a mnt/dentry pair is only
garunteed to be safe if they are already used in an open struct file.  To
make sure this is the case don't store and use a struct path in fsnotify,
always use a struct file.

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

5 files changed, 30 insertions, 32 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index f3c40c0e2b86..c2a3029052bc 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -17,9 +17,9 @@ static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new)
 	    old->data_type == new->data_type &&
 	    old->tgid == new->tgid) {
 		switch (old->data_type) {
-		case (FSNOTIFY_EVENT_PATH):
-			if ((old->path.mnt == new->path.mnt) &&
-			    (old->path.dentry == new->path.dentry))
+		case (FSNOTIFY_EVENT_FILE):
+			if ((old->file->f_path.mnt == new->file->f_path.mnt) &&
+			    (old->file->f_path.dentry == new->file->f_path.dentry))
 				return true;
 		case (FSNOTIFY_EVENT_NONE):
 			return true;
@@ -226,7 +226,7 @@ static bool fanotify_should_send_event(struct fsnotify_group *group, struct inod
 		return false;
 
 	/* if we don't have enough info to send an event to userspace say no */
-	if (data_type != FSNOTIFY_EVENT_PATH)
+	if (data_type != FSNOTIFY_EVENT_FILE)
 		return false;
 
 	if (mnt)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 7182c83be90e..50cea74bf1c8 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -65,7 +65,7 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
 	if (client_fd < 0)
 		return client_fd;
 
-	if (event->data_type != FSNOTIFY_EVENT_PATH) {
+	if (event->data_type != FSNOTIFY_EVENT_FILE) {
 		WARN_ON(1);
 		put_unused_fd(client_fd);
 		return -EINVAL;
@@ -75,8 +75,8 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
 	 * we need a new file handle for the userspace program so it can read even if it was
 	 * originally opened O_WRONLY.
 	 */
-	dentry = dget(event->path.dentry);
-	mnt = mntget(event->path.mnt);
+	dentry = dget(event->file->f_path.dentry);
+	mnt = mntget(event->file->f_path.mnt);
 	/* it's possible this event was an overflow event.  in that case dentry and mnt
 	 * are NULL;  That's fine, just don't call dentry open */
 	if (dentry && mnt)
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 72aae4045314..4788c866473a 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -84,7 +84,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
 }
 
 /* Notify this dentry's parent about a child's events. */
-void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
 {
 	struct dentry *parent;
 	struct inode *p_inode;
@@ -92,7 +92,7 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 	bool should_update_children = false;
 
 	if (!dentry)
-		dentry = path->dentry;
+		dentry = file->f_path.dentry;
 
 	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
 		return;
@@ -124,8 +124,8 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 		 * specifies these are events which came from a child. */
 		mask |= FS_EVENT_ON_CHILD;
 
-		if (path)
-			fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
+		if (file)
+			fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE,
 				 dentry->d_name.name, 0);
 		else
 			fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
@@ -154,10 +154,10 @@ void __fsnotify_flush_ignored_mask(struct inode *inode, void *data, int data_is)
 		spin_unlock(&inode->i_lock);
 	}
 
-	if (data_is == FSNOTIFY_EVENT_PATH) {
+	if (data_is == FSNOTIFY_EVENT_FILE) {
 		struct vfsmount *mnt;
 
-		mnt = ((struct path *)data)->mnt;
+		mnt = ((struct file *)data)->f_path.mnt;
 		if (mnt && !hlist_empty(&mnt->mnt_fsnotify_marks)) {
 			spin_lock(&mnt->mnt_root->d_lock);
 			hlist_for_each_entry(mark, node, &mnt->mnt_fsnotify_marks, m.m_list) {
@@ -228,8 +228,8 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
 	    !(test_mask & fsnotify_vfsmount_mask))
 		return 0;
  
-	if (data_is == FSNOTIFY_EVENT_PATH)
-		mnt = ((struct path *)data)->mnt;
+	if (data_is == FSNOTIFY_EVENT_FILE)
+		mnt = ((struct file *)data)->f_path.mnt;
 
 	/* if this inode's directed listeners don't care and nothing on the vfsmount
 	 * listeners list cares, nothing to do */
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 73a1106b3542..3c506e0364cc 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -52,9 +52,9 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new
 			    !strcmp(old->file_name, new->file_name))
 				return true;
 			break;
-		case (FSNOTIFY_EVENT_PATH):
-			if ((old->path.mnt == new->path.mnt) &&
-			    (old->path.dentry == new->path.dentry))
+		case (FSNOTIFY_EVENT_FILE):
+			if ((old->file->f_path.mnt == new->file->f_path.mnt) &&
+			    (old->file->f_path.dentry == new->file->f_path.dentry))
 				return true;
 			break;
 		case (FSNOTIFY_EVENT_NONE):
@@ -165,10 +165,10 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode
 	send = (fsn_mark->mask & mask);
 
 	if (send && (fsn_mark->mask & FS_EXCL_UNLINK) &&
-	    (data_type == FSNOTIFY_EVENT_PATH)) {
-		struct path *path  = data;
+	    (data_type == FSNOTIFY_EVENT_FILE)) {
+		struct file *file  = data;
 
-		if (d_unlinked(path->dentry))
+		if (d_unlinked(file->f_path.dentry))
 			send = false;
 	}
 
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index f39260f8f865..c106cdd7ff5e 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -31,6 +31,7 @@
  * allocated and used.
  */
 
+#include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -89,8 +90,8 @@ void fsnotify_put_event(struct fsnotify_event *event)
 	if (atomic_dec_and_test(&event->refcnt)) {
 		pr_debug("%s: event=%p\n", __func__, event);
 
-		if (event->data_type == FSNOTIFY_EVENT_PATH)
-			path_put(&event->path);
+		if (event->data_type == FSNOTIFY_EVENT_FILE)
+			fput(event->file);
 
 		BUG_ON(!list_empty(&event->private_data_list));
 
@@ -375,8 +376,8 @@ struct fsnotify_event *fsnotify_clone_event(struct fsnotify_event *old_event)
 		}
 	}
 	event->tgid = get_pid(old_event->tgid);
-	if (event->data_type == FSNOTIFY_EVENT_PATH)
-		path_get(&event->path);
+	if (event->data_type == FSNOTIFY_EVENT_FILE)
+		get_file(event->file);
 
 	return event;
 }
@@ -423,11 +424,9 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
 	event->data_type = data_type;
 
 	switch (data_type) {
-	case FSNOTIFY_EVENT_PATH: {
-		struct path *path = data;
-		event->path.dentry = path->dentry;
-		event->path.mnt = path->mnt;
-		path_get(&event->path);
+	case FSNOTIFY_EVENT_FILE: {
+		event->file = data;
+		get_file(event->file);
 		break;
 	}
 	case FSNOTIFY_EVENT_INODE:
@@ -435,8 +434,7 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
 		break;
 	case FSNOTIFY_EVENT_NONE:
 		event->inode = NULL;
-		event->path.dentry = NULL;
-		event->path.mnt = NULL;
+		event->file = NULL;
 		break;
 	default:
 		BUG();