linux-ext4 - [PATCH RFC 4/7] libfs: Support revalidation of encrypted case-insensitive dentries

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Date:   Wed,  1 Jun 2022 16:44:34 -0400
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     viro@...iv.linux.org.uk, tytso@....edu, jaegeuk@...nel.org
Cc:     ebiggers@...nel.org, linux-fsdevel@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        kernel@...labora.com
Subject: [PATCH RFC 4/7] libfs: Support revalidation of encrypted case-insensitive dentries

Preserve the existing behavior for encrypted directories, by rejecting
negative dentries of encrypted+casefolded directories.  This allows
generic_ci_d_revalidate to be used by filesystems with both features
enabled, as long as the directory is either casefolded or encrypted, but
not both at the same time.

Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
 fs/libfs.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/libfs.c b/fs/libfs.c
index 618a85c08aa7..fe22738291e4 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1461,6 +1461,9 @@ static inline int generic_ci_d_revalidate(struct dentry *dentry,
 		const struct inode *dir = READ_ONCE(parent->d_inode);
 
 		if (dir && needs_casefold(dir)) {
+			if (IS_ENCRYPTED(dir))
+				return 0;
+
 			if (!d_is_casefold_lookup(dentry))
 				return 0;
 
@@ -1470,7 +1473,8 @@ static inline int generic_ci_d_revalidate(struct dentry *dentry,
 				return 0;
 		}
 	}
-	return 1;
+
+	return fscrypt_d_revalidate(dentry, flags);
 }
 
 static const struct dentry_operations generic_ci_dentry_ops = {
@@ -1490,7 +1494,7 @@ static const struct dentry_operations generic_encrypted_dentry_ops = {
 static const struct dentry_operations generic_encrypted_ci_dentry_ops = {
 	.d_hash = generic_ci_d_hash,
 	.d_compare = generic_ci_d_compare,
-	.d_revalidate = fscrypt_d_revalidate,
+	.d_revalidate_name = generic_ci_d_revalidate,
 };
 #endif
 
-- 
2.36.1