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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

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);

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);

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);

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);
 

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;

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() */
 }

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);
 			}
 		}
 	}

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"

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)

fs/notify/fsnotify.c

@@ -94,47 +94,6 @@ void fsnotify_sb_delete(struct super_block *sb)
 	fsnotify_clear_marks_by_sb(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

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)

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)

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;

include/linux/fsnotify.h

@@ -188,6 +188,19 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
 	fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, &new_dentry->d_name, 0);
 }
 
+/*
+ * 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
  */
@@ -198,6 +211,19 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 	fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 }
 
+/*
+ * 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
  */

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)
 {}
 

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;