linux-ext4 - [PATCH v13 7/9] f2fs: Log error when lookup of encoded dentry fails

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Message-Id: <20240305101608.67943-8-eugen.hristev@collabora.com>
Date: Tue,  5 Mar 2024 12:16:06 +0200
From: Eugen Hristev <eugen.hristev@...labora.com>
To: tytso@....edu,
	adilger.kernel@...ger.ca,
	linux-ext4@...r.kernel.org,
	jaegeuk@...nel.org,
	chao@...nel.org,
	linux-f2fs-devel@...ts.sourceforge.net,
	linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	kernel@...labora.com,
	eugen.hristev@...labora.com,
	viro@...iv.linux.org.uk,
	brauner@...nel.org,
	jack@...e.cz,
	krisman@...e.de
Subject: [PATCH v13 7/9] f2fs: Log error when lookup of encoded dentry fails

If the volume is in strict mode, generi c_ci_compare can report a broken
encoding name.  This will not trigger on a bad lookup, which is caught
earlier, only if the actual disk name is bad.

Suggested-by: Gabriel Krisman Bertazi <krisman@...e.de>
Signed-off-by: Eugen Hristev <eugen.hristev@...labora.com>
---
 fs/f2fs/dir.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 0601b4c8bacc..1bb98970a56a 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -190,11 +190,22 @@ static inline int f2fs_match_name(const struct inode *dir,
 	struct fscrypt_name f;
 
 #if IS_ENABLED(CONFIG_UNICODE)
-	if (fname->cf_name.name)
-		return generic_ci_match(dir, fname->usr_fname,
-					&fname->cf_name,
-					de_name, de_name_len);
-
+	if (fname->cf_name.name) {
+		int ret = generic_ci_match(dir, fname->usr_fname,
+					   &fname->cf_name,
+					   de_name, de_name_len);
+		if (ret < 0) {
+			/*
+			 * Treat comparison errors as not a match.  The
+			 * only case where it happens is on a disk
+			 * corruption or ENOMEM.
+			 */
+			if (ret == -EINVAL)
+				f2fs_warn(F2FS_SB(dir->i_sb),
+					"Directory contains filename that is invalid UTF-8");
+		}
+		return ret;
+	}
 #endif
 	f.usr_fname = fname->usr_fname;
 	f.disk_name = fname->disk_name;
-- 
2.34.1