From 942b438c7399950a72082f58dddb09ec43a49734 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 11 Jan 2021 12:35:48 -0500 Subject: [PATCH] ceph: decode alternate_name in lease info 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 Signed-off-by: Xiubo Li --- fs/ceph/mds_client.c | 43 +++++++++++++++++++++++++++++++++---------- fs/ceph/mds_client.h | 5 +++++ 2 files changed, 38 insertions(+), 10 deletions(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 8e80ca128bd95..c5b2990457ba2 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -308,27 +308,47 @@ bad: 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; + void *lend; + 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); + lend = *p + struct_len; + 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; + } + } + *p = lend; return 0; bad: return -EIO; @@ -358,7 +378,8 @@ 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; } @@ -425,9 +446,11 @@ 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 01da3241e0e2c..46e33320a70d7 100644 --- a/fs/ceph/mds_client.h +++ b/fs/ceph/mds_client.h @@ -43,6 +43,7 @@ enum ceph_feature_type { CEPHFS_FEATURE_MULTI_RECONNECT, \ CEPHFS_FEATURE_DELEG_INO, \ CEPHFS_FEATURE_METRIC_COLLECT, \ + CEPHFS_FEATURE_ALTERNATE_NAME, \ CEPHFS_FEATURE_NOTIFY_SESSION_STATE, \ } @@ -94,7 +95,9 @@ 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; @@ -118,7 +121,9 @@ 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; struct ceph_mds_reply_xattr xattr_info; -- 2.39.5