Merge tag 'fsnotify_for_v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "This contains cleanups of the fsnotify name removal hook and also a
  patch to disable fanotify permission events for 'proc' filesystem"

* tag 'fsnotify_for_v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: get rid of fsnotify_nameremove()
  fsnotify: move fsnotify_nameremove() hook out of d_delete()
  configfs: call fsnotify_rmdir() hook
  debugfs: call fsnotify_{unlink,rmdir}() hooks
  debugfs: simplify __debugfs_remove_file()
  devpts: call fsnotify_unlink() hook
  tracefs: call fsnotify_{unlink,rmdir}() hooks
  rpc_pipefs: call fsnotify_{unlink,rmdir}() hooks
  btrfs: call fsnotify_rmdir() hook
  fsnotify: add empty fsnotify_{unlink,rmdir}() hooks
  fanotify: Disallow permission events for proc filesystem

16 files changed, 76 insertions, 71 deletions

diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c
index 057b8d322422..361088a5edb9 100644
--- a/fs/afs/dir_silly.c
+++ b/fs/afs/dir_silly.c
@@ -60,11 +60,6 @@ static int afs_do_silly_rename(struct afs_vnode *dvnode, struct afs_vnode *vnode
                 if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                         afs_edit_dir_add(dvnode, &new->d_name,
                                          &vnode->fid, afs_edit_dir_for_silly_1);
-
-                /* vfs_unlink and the like do not issue this when a file is
-                 * sillyrenamed, so do it here.
-                 */
-                fsnotify_nameremove(old, 0);
         }
 
         kfree(scb);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2a1be0d1a698..56ae2f659b6d 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2928,8 +2928,10 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
         inode_lock(inode);
         err = btrfs_delete_subvolume(dir, dentry);
         inode_unlock(inode);
-        if (!err)
+        if (!err) {
+                fsnotify_rmdir(dir, dentry);
                 d_delete(dentry);
+        }
 
 out_dput:
         dput(dentry);
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index d2ca5287762d..92112915de8e 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -13,6 +13,7 @@
 #undef DEBUG
 
 #include <linux/fs.h>
+#include <linux/fsnotify.h>
 #include <linux/mount.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -1788,6 +1789,7 @@ void configfs_unregister_group(struct config_group *group)
         configfs_detach_group(&group->cg_item);
         d_inode(dentry)->i_flags |= S_DEAD;
         dont_mount(dentry);
+        fsnotify_rmdir(d_inode(parent), dentry);
         d_delete(dentry);
         inode_unlock(d_inode(parent));
 
@@ -1916,6 +1918,7 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
         configfs_detach_group(&group->cg_item);
         d_inode(dentry)->i_flags |= S_DEAD;
         dont_mount(dentry);
+        fsnotify_rmdir(d_inode(root), dentry);
         inode_unlock(d_inode(dentry));
 
         d_delete(dentry);
diff --git a/fs/dcache.c b/fs/dcache.c
index c435398f2c81..f41121e5d1ec 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2372,7 +2372,6 @@ EXPORT_SYMBOL(d_hash_and_lookup);
 void d_delete(struct dentry * dentry)
 {
         struct inode *inode = dentry->d_inode;
-        int isdir = d_is_dir(dentry);
 
         spin_lock(&inode->i_lock);
         spin_lock(&dentry->d_lock);
@@ -2387,7 +2386,6 @@ void d_delete(struct dentry * dentry)
                 spin_unlock(&dentry->d_lock);
                 spin_unlock(&inode->i_lock);
         }
-        fsnotify_nameremove(dentry, isdir);
 }
 EXPORT_SYMBOL(d_delete);
 
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index acef14ad53db..1e444fe1f778 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -617,13 +617,10 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
 
-static void __debugfs_remove_file(struct dentry *dentry, struct dentry *parent)
+static void __debugfs_file_removed(struct dentry *dentry)
 {
         struct debugfs_fsdata *fsd;
 
-        simple_unlink(d_inode(parent), dentry);
-        d_delete(dentry);
-
         /*
          * Paired with the closing smp_mb() implied by a successful
          * cmpxchg() in debugfs_file_get(): either
@@ -644,16 +641,18 @@ static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
 
         if (simple_positive(dentry)) {
                 dget(dentry);
-                if (!d_is_reg(dentry)) {
-                        if (d_is_dir(dentry))
-                                ret = simple_rmdir(d_inode(parent), dentry);
-                        else
-                                simple_unlink(d_inode(parent), dentry);
+                if (d_is_dir(dentry)) {
+                        ret = simple_rmdir(d_inode(parent), dentry);
                         if (!ret)
-                                d_delete(dentry);
+                                fsnotify_rmdir(d_inode(parent), dentry);
                 } else {
-                        __debugfs_remove_file(dentry, parent);
+                        simple_unlink(d_inode(parent), dentry);
+                        fsnotify_unlink(d_inode(parent), dentry);
                 }
+                if (!ret)
+                        d_delete(dentry);
+                if (d_is_reg(dentry))
+                        __debugfs_file_removed(dentry);
                 dput(dentry);
         }
         return ret;
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 2c14ae044dce..beeadca23b05 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -621,6 +621,7 @@ void devpts_pty_kill(struct dentry *dentry)
 
         dentry->d_fsdata = NULL;
         drop_nlink(dentry->d_inode);
+        fsnotify_unlink(d_inode(dentry->d_parent), dentry);
         d_delete(dentry);
         dput(dentry);   /* d_alloc_name() in devpts_pty_new() */
 }
diff --git a/fs/namei.c b/fs/namei.c
index 20831c2fbb34..209c51a5226c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3883,6 +3883,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
         dentry->d_inode->i_flags |= S_DEAD;
         dont_mount(dentry);
         detach_mounts(dentry);
+        fsnotify_rmdir(dir, dentry);
 
 out:
         inode_unlock(dentry->d_inode);
@@ -3999,6 +4000,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate
                         if (!error) {
                                 dont_mount(dentry);
                                 detach_mounts(dentry);
+                                fsnotify_unlink(dir, dentry);
                         }
                 }
         }
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 52d533967485..0effeee28352 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -396,12 +396,6 @@ nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
                 nfs_cancel_async_unlink(dentry);
                 return;
         }
-
-        /*
-         * vfs_unlink and the like do not issue this when a file is
-         * sillyrenamed, so do it here.
-         */
-        fsnotify_nameremove(dentry, 0);
 }
 
 #define SILLYNAME_PREFIX ".nfs"
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index a90bb19dcfa2..91006f47e420 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -920,6 +920,22 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
         return 0;
 }
 
+static int fanotify_events_supported(struct path *path, __u64 mask)
+{
+        /*
+         * Some filesystems such as 'proc' acquire unusual locks when opening
+         * files. For them fanotify permission events have high chances of
+         * deadlocking the system - open done when reporting fanotify event
+         * blocks on this "unusual" lock while another process holding the lock
+         * waits for fanotify permission event to be answered. Just disallow
+         * permission events for such filesystems.
+         */
+        if (mask & FANOTIFY_PERM_EVENTS &&
+            path->mnt->mnt_sb->s_type->fs_flags & FS_DISALLOW_NOTIFY_PERM)
+                return -EINVAL;
+        return 0;
+}
+
 static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
                             int dfd, const char  __user *pathname)
 {
@@ -1018,6 +1034,12 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
         if (ret)
                 goto fput_and_out;
 
+        if (flags & FAN_MARK_ADD) {
+                ret = fanotify_events_supported(&path, mask);
+                if (ret)
+                        goto path_put_and_out;
+        }
+
         if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
                 ret = fanotify_test_fid(&path, &__fsid);
                 if (ret)
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 4eb2ebfac468..2ecef6155fc0 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -95,47 +95,6 @@ void fsnotify_sb_delete(struct super_block *sb)
 }
 
 /*
- * fsnotify_nameremove - a filename was removed from a directory
- *
- * This is mostly called under parent vfs inode lock so name and
- * dentry->d_parent should be stable. However there are some corner cases where
- * inode lock is not held. So to be on the safe side and be reselient to future
- * callers and out of tree users of d_delete(), we do not assume that d_parent
- * and d_name are stable and we use dget_parent() and
- * take_dentry_name_snapshot() to grab stable references.
- */
-void fsnotify_nameremove(struct dentry *dentry, int isdir)
-{
-        struct dentry *parent;
-        struct name_snapshot name;
-        __u32 mask = FS_DELETE;
-
-        /* d_delete() of pseudo inode? (e.g. __ns_get_path() playing tricks) */
-        if (IS_ROOT(dentry))
-                return;
-
-        if (isdir)
-                mask |= FS_ISDIR;
-
-        parent = dget_parent(dentry);
-        /* Avoid unneeded take_dentry_name_snapshot() */
-        if (!(d_inode(parent)->i_fsnotify_mask & FS_DELETE) &&
-            !(dentry->d_sb->s_fsnotify_mask & FS_DELETE))
-                goto out_dput;
-
-        take_dentry_name_snapshot(&name, dentry);
-
-        fsnotify(d_inode(parent), mask, d_inode(dentry), FSNOTIFY_EVENT_INODE,
-                 &name.name, 0);
-
-        release_dentry_name_snapshot(&name);
-
-out_dput:
-        dput(parent);
-}
-EXPORT_SYMBOL(fsnotify_nameremove);
-
-/*
  * Given an inode, first check if we care what happens to our children.  Inotify
  * and dnotify both tell their parents about events.  If we care about any event
  * on a child we run all of our children and set a dentry flag saying that the
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 8b145e7b9661..522199e9525e 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -211,7 +211,7 @@ static struct file_system_type proc_fs_type = {
         .init_fs_context        = proc_init_fs_context,
         .parameters             = &proc_fs_parameters,
         .kill_sb                = proc_kill_sb,
-        .fs_flags               = FS_USERNS_MOUNT,
+        .fs_flags               = FS_USERNS_MOUNT | FS_DISALLOW_NOTIFY_PERM,
 };
 
 void __init proc_root_init(void)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index a5bab190a297..eeeae0475da9 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -505,9 +505,12 @@ static int __tracefs_remove(struct dentry *dentry, struct dentry *parent)
                         switch (dentry->d_inode->i_mode & S_IFMT) {
                         case S_IFDIR:
                                 ret = simple_rmdir(parent->d_inode, dentry);
+                                if (!ret)
+                                        fsnotify_rmdir(parent->d_inode, dentry);
                                 break;
                         default:
                                 simple_unlink(parent->d_inode, dentry);
+                                fsnotify_unlink(parent->d_inode, dentry);
                                 break;
                         }
                         if (!ret)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4fb399b77327..201ebb1e062d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2184,6 +2184,7 @@ struct file_system_type {
 #define FS_BINARY_MOUNTDATA     2
 #define FS_HAS_SUBTYPE          4
 #define FS_USERNS_MOUNT         8       /* Can be mounted by userns root */
+#define FS_DISALLOW_NOTIFY_PERM 16      /* Disable fanotify permission events */
 #define FS_RENAME_DOES_D_MOVE   32768   /* FS will handle d_move() during rename() internally. */
         int (*init_fs_context)(struct fs_context *);
         const struct fs_parameter_description *parameters;
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 94972e8eb6d1..a2d5d175d3c1 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -189,6 +189,19 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
 }
 
 /*
+ * fsnotify_unlink - 'name' was unlinked
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ */
+static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
+{
+        /* Expected to be called before d_delete() */
+        WARN_ON_ONCE(d_is_negative(dentry));
+
+        fsnotify_dirent(dir, dentry, FS_DELETE);
+}
+
+/*
  * fsnotify_mkdir - directory 'name' was created
  */
 static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
@@ -199,6 +212,19 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 }
 
 /*
+ * fsnotify_rmdir - directory 'name' was removed
+ *
+ * Caller must make sure that dentry->d_name is stable.
+ */
+static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
+{
+        /* Expected to be called before d_delete() */
+        WARN_ON_ONCE(d_is_negative(dentry));
+
+        fsnotify_dirent(dir, dentry, FS_DELETE | FS_ISDIR);
+}
+
+/*
  * fsnotify_access - file was read
  */
 static inline void fsnotify_access(struct file *file)
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index d4844cad2c2b..2de3b2ddd19a 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -357,7 +357,6 @@ extern int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u
 extern void __fsnotify_inode_delete(struct inode *inode);
 extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
 extern void fsnotify_sb_delete(struct super_block *sb);
-extern void fsnotify_nameremove(struct dentry *dentry, int isdir);
 extern u32 fsnotify_get_cookie(void);
 
 static inline int fsnotify_inode_watches_children(struct inode *inode)
@@ -527,9 +526,6 @@ static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
 static inline void fsnotify_sb_delete(struct super_block *sb)
 {}
 
-static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
-{}
-
 static inline void fsnotify_update_flags(struct dentry *dentry)
 {}
 
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 126d31472a99..73bd62979fe7 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -598,6 +598,8 @@ static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 
         dget(dentry);
         ret = simple_rmdir(dir, dentry);
+        if (!ret)
+                fsnotify_rmdir(dir, dentry);
         d_delete(dentry);
         dput(dentry);
         return ret;
@@ -609,6 +611,8 @@ static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 
         dget(dentry);
         ret = simple_unlink(dir, dentry);
+        if (!ret)
+                fsnotify_unlink(dir, dentry);
         d_delete(dentry);
         dput(dentry);
         return ret;