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>

8 files changed, 56 insertions, 63 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();
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 59d0df43ff9d..e4e2204187ee 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -26,19 +26,18 @@ static inline void fsnotify_d_instantiate(struct dentry *dentry,
 }
 
 /* Notify this dentry's parent about a child's events. */
-static inline void fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+static inline void fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
 {
         if (!dentry)
-                dentry = path->dentry;
+                dentry = file->f_path.dentry;
 
-        __fsnotify_parent(path, dentry, mask);
+        __fsnotify_parent(file, dentry, mask);
 }
 
 /* simple call site for access decisions */
 static inline int fsnotify_perm(struct file *file, int mask)
 {
-        struct path *path = &file->f_path;
-        struct inode *inode = path->dentry->d_inode;
+        struct inode *inode = file->f_path.dentry->d_inode;
         __u32 fsnotify_mask = 0;
 
         if (file->f_mode & FMODE_NONOTIFY)
@@ -52,7 +51,7 @@ static inline int fsnotify_perm(struct file *file, int mask)
         else
                 BUG();
 
-        return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+        return fsnotify(inode, fsnotify_mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
 }
 
 /*
@@ -187,16 +186,15 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
  */
 static inline void fsnotify_access(struct file *file)
 {
-        struct path *path = &file->f_path;
-        struct inode *inode = path->dentry->d_inode;
+        struct inode *inode = file->f_path.dentry->d_inode;
         __u32 mask = FS_ACCESS;
 
         if (S_ISDIR(inode->i_mode))
                 mask |= FS_IN_ISDIR;
 
         if (!(file->f_mode & FMODE_NONOTIFY)) {
-                fsnotify_parent(path, NULL, mask);
-                fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+                fsnotify_parent(file, NULL, mask);
+                fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
         }
 }
 
@@ -205,16 +203,15 @@ static inline void fsnotify_access(struct file *file)
  */
 static inline void fsnotify_modify(struct file *file)
 {
-        struct path *path = &file->f_path;
-        struct inode *inode = path->dentry->d_inode;
+        struct inode *inode = file->f_path.dentry->d_inode;
         __u32 mask = FS_MODIFY;
 
         if (S_ISDIR(inode->i_mode))
                 mask |= FS_IN_ISDIR;
 
         if (!(file->f_mode & FMODE_NONOTIFY)) {
-                fsnotify_parent(path, NULL, mask);
-                fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+                fsnotify_parent(file, NULL, mask);
+                fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
         }
 }
 
@@ -223,16 +220,15 @@ static inline void fsnotify_modify(struct file *file)
  */
 static inline void fsnotify_open(struct file *file)
 {
-        struct path *path = &file->f_path;
-        struct inode *inode = path->dentry->d_inode;
+        struct inode *inode = file->f_path.dentry->d_inode;
         __u32 mask = FS_OPEN;
 
         if (S_ISDIR(inode->i_mode))
                 mask |= FS_IN_ISDIR;
 
         if (!(file->f_mode & FMODE_NONOTIFY)) {
-                fsnotify_parent(path, NULL, mask);
-                fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+                fsnotify_parent(file, NULL, mask);
+                fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
         }
 }
 
@@ -241,7 +237,6 @@ static inline void fsnotify_open(struct file *file)
  */
 static inline void fsnotify_close(struct file *file)
 {
-        struct path *path = &file->f_path;
         struct inode *inode = file->f_path.dentry->d_inode;
         fmode_t mode = file->f_mode;
         __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
@@ -250,8 +245,8 @@ static inline void fsnotify_close(struct file *file)
                 mask |= FS_IN_ISDIR;
 
         if (!(file->f_mode & FMODE_NONOTIFY)) {
-                fsnotify_parent(path, NULL, mask);
-                fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+                fsnotify_parent(file, NULL, mask);
+                fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
         }
 }
 
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 564b5ea4a831..3410d388163e 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -223,20 +223,20 @@ struct fsnotify_event {
         /* to_tell may ONLY be dereferenced during handle_event(). */
         struct inode *to_tell;  /* either the inode the event happened to or its parent */
         /*
-         * depending on the event type we should have either a path or inode
-         * We hold a reference on path, but NOT on inode.  Since we have the ref on
-         * the path, it may be dereferenced at any point during this object's
+         * depending on the event type we should have either a file or inode
+         * We hold a reference on file, but NOT on inode.  Since we have the ref on
+         * the file, it may be dereferenced at any point during this object's
          * lifetime.  That reference is dropped when this object's refcnt hits
-         * 0.  If this event contains an inode instead of a path, the inode may
+         * 0.  If this event contains an inode instead of a file, the inode may
          * ONLY be used during handle_event().
          */
         union {
-                struct path path;
+                struct file *file;
                 struct inode *inode;
         };
 /* when calling fsnotify tell it if the data is a path or inode */
 #define FSNOTIFY_EVENT_NONE     0
-#define FSNOTIFY_EVENT_PATH     1
+#define FSNOTIFY_EVENT_FILE     1
 #define FSNOTIFY_EVENT_INODE    2
         int data_type;          /* which of the above union we have */
         atomic_t refcnt;        /* how many groups still are using/need to send this event */
@@ -311,7 +311,7 @@ struct fsnotify_mark {
 /* main fsnotify call to send events */
 extern int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
                     const unsigned char *name, u32 cookie);
-extern void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
+extern void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask);
 extern void __fsnotify_inode_delete(struct inode *inode);
 extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
 extern u32 fsnotify_get_cookie(void);
@@ -444,7 +444,7 @@ static inline int fsnotify(struct inode *to_tell, __u32 mask, void *data, int da
         return 0;
 }
 
-static inline void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+static inline void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
 {}
 
 static inline void __fsnotify_inode_delete(struct inode *inode)
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 7499397a6100..b955a22d8ff1 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -545,8 +545,8 @@ static int audit_watch_handle_event(struct fsnotify_group *group, struct fsnotif
                 return 0;
 
         switch (event->data_type) {
-        case (FSNOTIFY_EVENT_PATH):
-                inode = event->path.dentry->d_inode;
+        case (FSNOTIFY_EVENT_FILE):
+                inode = event->file->f_path.dentry->d_inode;
                 break;
         case (FSNOTIFY_EVENT_INODE):
                 inode = event->inode;