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From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	dhowells@redhat.com, xiubli@redhat.com, lhenriques@suse.de,
	khiremat@redhat.com, ebiggers@kernel.org
Subject: [RFC PATCH v8 12/24] ceph: decode alternate_name in lease info
Date: Thu, 26 Aug 2021 12:20:02 -0400	[thread overview]
Message-ID: <20210826162014.73464-13-jlayton@kernel.org> (raw)
In-Reply-To: <20210826162014.73464-1-jlayton@kernel.org>

Ceph is a bit different from local filesystems, in that we don't want
to store filenames as raw binary data, since we may also be dealing
with clients that don't support fscrypt.

We could just base64-encode the encrypted filenames, but that could
leave us with filenames longer than NAME_MAX. It turns out that the
MDS doesn't care much about filename length, but the clients do.

To manage this, we've added a new "alternate name" field that can be
optionally added to any dentry that we'll use to store the binary
crypttext of the filename if its base64-encoded value will be longer
than NAME_MAX. When a dentry has one of these names attached, the MDS
will send it along in the lease info, which we can then store for
later usage.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/mds_client.c | 40 ++++++++++++++++++++++++++++++----------
 fs/ceph/mds_client.h | 11 +++++++----
 2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 449b4e78366e..058480708897 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -306,27 +306,44 @@ static int parse_reply_info_dir(void **p, void *end,
 
 static int parse_reply_info_lease(void **p, void *end,
 				  struct ceph_mds_reply_lease **lease,
-				  u64 features)
+				  u64 features, u32 *altname_len, u8 **altname)
 {
+	u8 struct_v;
+	u32 struct_len;
+
 	if (features == (u64)-1) {
-		u8 struct_v, struct_compat;
-		u32 struct_len;
+		u8 struct_compat;
+
 		ceph_decode_8_safe(p, end, struct_v, bad);
 		ceph_decode_8_safe(p, end, struct_compat, bad);
+
 		/* struct_v is expected to be >= 1. we only understand
 		 * encoding whose struct_compat == 1. */
 		if (!struct_v || struct_compat != 1)
 			goto bad;
+
 		ceph_decode_32_safe(p, end, struct_len, bad);
-		ceph_decode_need(p, end, struct_len, bad);
-		end = *p + struct_len;
+	} else {
+		struct_len = sizeof(**lease);
+		*altname_len = 0;
+		*altname = NULL;
 	}
 
-	ceph_decode_need(p, end, sizeof(**lease), bad);
+	ceph_decode_need(p, end, struct_len, bad);
 	*lease = *p;
 	*p += sizeof(**lease);
-	if (features == (u64)-1)
-		*p = end;
+
+	if (features == (u64)-1) {
+		if (struct_v >= 2) {
+			ceph_decode_32_safe(p, end, *altname_len, bad);
+			ceph_decode_need(p, end, *altname_len, bad);
+			*altname = *p;
+			*p += *altname_len;
+		} else {
+			*altname = NULL;
+			*altname_len = 0;
+		}
+	}
 	return 0;
 bad:
 	return -EIO;
@@ -356,7 +373,8 @@ static int parse_reply_info_trace(void **p, void *end,
 		info->dname = *p;
 		*p += info->dname_len;
 
-		err = parse_reply_info_lease(p, end, &info->dlease, features);
+		err = parse_reply_info_lease(p, end, &info->dlease, features,
+					     &info->altname_len, &info->altname);
 		if (err < 0)
 			goto out_bad;
 	}
@@ -423,9 +441,11 @@ static int parse_reply_info_readdir(void **p, void *end,
 		dout("parsed dir dname '%.*s'\n", rde->name_len, rde->name);
 
 		/* dentry lease */
-		err = parse_reply_info_lease(p, end, &rde->lease, features);
+		err = parse_reply_info_lease(p, end, &rde->lease, features,
+					     &rde->altname_len, &rde->altname);
 		if (err)
 			goto out_bad;
+
 		/* inode */
 		err = parse_reply_info_in(p, end, &rde->inode, features);
 		if (err < 0)
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index e7d2c8a1b9c1..128901a847af 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -29,8 +29,8 @@ enum ceph_feature_type {
 	CEPHFS_FEATURE_MULTI_RECONNECT,
 	CEPHFS_FEATURE_DELEG_INO,
 	CEPHFS_FEATURE_METRIC_COLLECT,
-
-	CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_METRIC_COLLECT,
+	CEPHFS_FEATURE_ALTERNATE_NAME,
+	CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_ALTERNATE_NAME,
 };
 
 /*
@@ -45,8 +45,7 @@ enum ceph_feature_type {
 	CEPHFS_FEATURE_MULTI_RECONNECT,		\
 	CEPHFS_FEATURE_DELEG_INO,		\
 	CEPHFS_FEATURE_METRIC_COLLECT,		\
-						\
-	CEPHFS_FEATURE_MAX,			\
+	CEPHFS_FEATURE_ALTERNATE_NAME,		\
 }
 #define CEPHFS_FEATURES_CLIENT_REQUIRED {}
 
@@ -98,7 +97,9 @@ struct ceph_mds_reply_info_in {
 
 struct ceph_mds_reply_dir_entry {
 	char                          *name;
+	u8			      *altname;
 	u32                           name_len;
+	u32			      altname_len;
 	struct ceph_mds_reply_lease   *lease;
 	struct ceph_mds_reply_info_in inode;
 	loff_t			      offset;
@@ -117,7 +118,9 @@ struct ceph_mds_reply_info_parsed {
 	struct ceph_mds_reply_info_in diri, targeti;
 	struct ceph_mds_reply_dirfrag *dirfrag;
 	char                          *dname;
+	u8			      *altname;
 	u32                           dname_len;
+	u32                           altname_len;
 	struct ceph_mds_reply_lease   *dlease;
 
 	/* extra */
-- 
2.31.1


  parent reply	other threads:[~2021-08-26 16:20 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26 16:19 [RFC PATCH v8 00/24] ceph+fscrypt: context, filename and symlink support Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 01/24] vfs: export new_inode_pseudo Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 02/24] fscrypt: export fscrypt_base64url_encode and fscrypt_base64url_decode Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 03/24] fscrypt: export fscrypt_fname_encrypt and fscrypt_fname_encrypted_size Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 04/24] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 05/24] ceph: preallocate inode for ops that may create one Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 06/24] ceph: parse new fscrypt_auth and fscrypt_file fields in inode traces Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 07/24] ceph: add fscrypt_* handling to caps.c Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 08/24] ceph: crypto context handling for ceph Jeff Layton
2021-08-26 16:19 ` [RFC PATCH v8 09/24] ceph: add ability to set fscrypt_auth via setattr Jeff Layton
2021-08-31  5:06   ` Xiubo Li
2021-08-31 12:43     ` Jeff Layton
2021-08-31 13:22       ` Xiubo Li
2021-08-31 13:50         ` Jeff Layton
2021-08-31 17:54           ` Eric Biggers
2021-09-01  0:53             ` Xiubo Li
2021-09-01  1:13           ` Xiubo Li
2021-09-01 12:02             ` Jeff Layton
2021-09-02  1:54               ` Xiubo Li
2021-08-26 16:20 ` [RFC PATCH v8 10/24] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 11/24] ceph: add fscrypt ioctls Jeff Layton
2021-08-26 16:20 ` Jeff Layton [this message]
2021-08-26 16:20 ` [RFC PATCH v8 13/24] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 14/24] ceph: add encrypted fname handling to ceph_mdsc_build_path Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 15/24] ceph: send altname in MClientRequest Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 16/24] ceph: encode encrypted name in dentry release Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 17/24] ceph: properly set DCACHE_NOKEY_NAME flag in lookup Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 18/24] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 19/24] ceph: add helpers for converting names for userland presentation Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 20/24] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 21/24] ceph: add support to readdir for encrypted filenames Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 22/24] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 23/24] ceph: make ceph_get_name decrypt filenames Jeff Layton
2021-08-26 16:20 ` [RFC PATCH v8 24/24] ceph: add a new ceph.fscrypt.auth vxattr Jeff Layton

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