1 files changed, 50 insertions, 24 deletions

diff --git a/fs/open.c b/fs/open.c
index e6911101fe71..1be20de9f283 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -81,14 +81,18 @@ long vfs_truncate(const struct path *path, loff_t length)
 	if (!S_ISREG(inode->i_mode))
 		return -EINVAL;
 
-	error = mnt_want_write(path->mnt);
-	if (error)
-		goto out;
-
 	idmap = mnt_idmap(path->mnt);
 	error = inode_permission(idmap, inode, MAY_WRITE);
 	if (error)
-		goto mnt_drop_write_and_out;
+		return error;
+
+	error = fsnotify_truncate_perm(path, length);
+	if (error)
+		return error;
+
+	error = mnt_want_write(path->mnt);
+	if (error)
+		return error;
 
 	error = -EPERM;
 	if (IS_APPEND(inode))
@@ -114,7 +118,7 @@ put_write_and_out:
 	put_write_access(inode);
 mnt_drop_write_and_out:
 	mnt_drop_write(path->mnt);
-out:
+
 	return error;
 }
 EXPORT_SYMBOL_GPL(vfs_truncate);
@@ -175,11 +179,18 @@ long do_ftruncate(struct file *file, loff_t length, int small)
 	/* Check IS_APPEND on real upper inode */
 	if (IS_APPEND(file_inode(file)))
 		return -EPERM;
-	sb_start_write(inode->i_sb);
+
 	error = security_file_truncate(file);
-	if (!error)
-		error = do_truncate(file_mnt_idmap(file), dentry, length,
-				    ATTR_MTIME | ATTR_CTIME, file);
+	if (error)
+		return error;
+
+	error = fsnotify_truncate_perm(&file->f_path, length);
+	if (error)
+		return error;
+
+	sb_start_write(inode->i_sb);
+	error = do_truncate(file_mnt_idmap(file), dentry, length,
+			    ATTR_MTIME | ATTR_CTIME, file);
 	sb_end_write(inode->i_sb);
 
 	return error;
@@ -402,7 +413,6 @@ static bool access_need_override_creds(int flags)
 
 static const struct cred *access_override_creds(void)
 {
-	const struct cred *old_cred;
 	struct cred *override_cred;
 
 	override_cred = prepare_creds();
@@ -447,13 +457,7 @@ static const struct cred *access_override_creds(void)
 	 * freeing.
 	 */
 	override_cred->non_rcu = 1;
-
-	old_cred = override_creds(override_cred);
-
-	/* override_cred() gets its own ref */
-	put_cred(override_cred);
-
-	return old_cred;
+	return override_creds(override_cred);
 }
 
 static long do_faccessat(int dfd, const char __user *filename, int mode, int flags)
@@ -523,7 +527,7 @@ out_path_release:
 	}
 out:
 	if (old_cred)
-		revert_creds(old_cred);
+		put_cred(revert_creds(old_cred));
 
 	return res;
 }
@@ -902,6 +906,7 @@ static int do_dentry_open(struct file *f,
 
 	if (unlikely(f->f_flags & O_PATH)) {
 		f->f_mode = FMODE_PATH | FMODE_OPENED;
+		file_set_fsnotify_mode(f, FMODE_NONOTIFY);
 		f->f_op = &empty_fops;
 		return 0;
 	}
@@ -929,6 +934,12 @@ static int do_dentry_open(struct file *f,
 	if (error)
 		goto cleanup_all;
 
+	/*
+	 * Set FMODE_NONOTIFY_* bits according to existing permission watches.
+	 * If FMODE_NONOTIFY mode was already set for an fanotify fd or for a
+	 * pseudo file, this call will not change the mode.
+	 */
+	file_set_fsnotify_mode_from_watchers(f);
 	error = fsnotify_open_perm(f);
 	if (error)
 		goto cleanup_all;
@@ -1105,6 +1116,23 @@ struct file *dentry_open(const struct path *path, int flags,
 }
 EXPORT_SYMBOL(dentry_open);
 
+struct file *dentry_open_nonotify(const struct path *path, int flags,
+				  const struct cred *cred)
+{
+	struct file *f = alloc_empty_file(flags, cred);
+	if (!IS_ERR(f)) {
+		int error;
+
+		file_set_fsnotify_mode(f, FMODE_NONOTIFY);
+		error = vfs_open(path, f);
+		if (error) {
+			fput(f);
+			f = ERR_PTR(error);
+		}
+	}
+	return f;
+}
+
 /**
  * dentry_create - Create and open a file
  * @path: path to create
@@ -1202,7 +1230,7 @@ inline struct open_how build_open_how(int flags, umode_t mode)
 inline int build_open_flags(const struct open_how *how, struct open_flags *op)
 {
 	u64 flags = how->flags;
-	u64 strip = __FMODE_NONOTIFY | O_CLOEXEC;
+	u64 strip = O_CLOEXEC;
 	int lookup_flags = 0;
 	int acc_mode = ACC_MODE(flags);
 
@@ -1210,9 +1238,7 @@ inline int build_open_flags(const struct open_how *how, struct open_flags *op)
 			 "struct open_flags doesn't yet handle flags > 32 bits");
 
 	/*
-	 * Strip flags that either shouldn't be set by userspace like
-	 * FMODE_NONOTIFY or that aren't relevant in determining struct
-	 * open_flags like O_CLOEXEC.
+	 * Strip flags that aren't relevant in determining struct open_flags.
 	 */
 	flags &= ~strip;
 
@@ -1504,7 +1530,7 @@ static int filp_flush(struct file *filp, fl_owner_t id)
 {
 	int retval = 0;
 
-	if (CHECK_DATA_CORRUPTION(file_count(filp) == 0,
+	if (CHECK_DATA_CORRUPTION(file_count(filp) == 0, filp,
 			"VFS: Close: file count is 0 (f_op=%ps)",
 			filp->f_op)) {
 		return 0;