[lustre-devel] [PATCH 07/32] lustre: enc: enc-unaware clients get ENOKEY if file not found

[James Simmons]

From: Sebastien Buisson <sbuisson at ddn.com>

To reduce issues with applications running on clients without keys
or without fscrypt support that check for the existence of a file in
an encrypted directory, return -ENOKEY instead of -ENOENT.
For encryption-unaware clients, this is done on server side in the
mdt layer, by checking if clients have the OBD_CONNECT2_ENCRYPT
connection flag.
For clients without the key, this is done in llite when the searched
filename is not in encoded form.

WC-bug-id: https://jira.whamcloud.com/browse/LU-15855
Lustre-commit: 00898697f998c095e ("LU-15855 enc: enc-unaware clients get ENOKEY if file not found")
Signed-off-by: Sebastien Buisson <sbuisson at ddn.com>
Reviewed-on: https://review.whamcloud.com/47349
Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
Reviewed-by: John L. Hammond <jhammond at whamcloud.com>
Reviewed-by: James Simmons <jsimmons at infradead.org>
Reviewed-by: Oleg Drokin <green at whamcloud.com>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
 fs/lustre/llite/crypto.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/fs/lustre/llite/crypto.c b/fs/lustre/llite/crypto.c
index f075b9a..ad045c3 100644
--- a/fs/lustre/llite/crypto.c
+++ b/fs/lustre/llite/crypto.c
@@ -233,21 +233,26 @@ int ll_setup_filename(struct inode *dir, const struct qstr *iname,
 		fid->f_ver = 0;
 	}
 	rc = fscrypt_setup_filename(dir, &dname, lookup, fname);
-	if (rc == -ENOENT && lookup &&
-	    ((is_root_inode(dir) && iname->len == strlen(dot_fscrypt_name) &&
-	      strncmp(iname->name, dot_fscrypt_name, iname->len) == 0) ||
-	     (!fscrypt_has_encryption_key(dir) &&
-	      unlikely(filename_is_volatile(iname->name, iname->len, NULL))))) {
-		/* In case of subdir mount of an encrypted directory, we allow
-		 * lookup of /.fscrypt directory.
-		 */
-		/* For purpose of migration or mirroring without enc key, we
-		 * allow lookup of volatile file without enc context.
-		 */
-		memset(fname, 0, sizeof(struct fscrypt_name));
-		fname->disk_name.name = (unsigned char *)iname->name;
-		fname->disk_name.len = iname->len;
-		rc = 0;
+	if (rc == -ENOENT && lookup) {
+		if (((is_root_inode(dir) &&
+		     iname->len == strlen(dot_fscrypt_name) &&
+		     strncmp(iname->name, dot_fscrypt_name, iname->len) == 0) ||
+		     (!fscrypt_has_encryption_key(dir) &&
+		      unlikely(filename_is_volatile(iname->name,
+						    iname->len, NULL))))) {
+			/* In case of subdir mount of an encrypted directory,
+			 * we allow lookup of /.fscrypt directory.
+			 */
+			/* For purpose of migration or mirroring without enc key,
+			 * we allow lookup of volatile file without enc context.
+			 */
+			memset(fname, 0, sizeof(struct fscrypt_name));
+			fname->disk_name.name = (unsigned char *)iname->name;
+			fname->disk_name.len = iname->len;
+			rc = 0;
+		} else if (!fscrypt_has_encryption_key(dir)) {
+			rc = -ENOKEY;
+		}
 	}
 	if (rc)
 		return rc;
-- 
1.8.3.1