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authorJeff Layton <jlayton@redhat.com>2017-10-23 17:58:40 +0300
committerIlya Dryomov <idryomov@gmail.com>2017-11-13 14:11:42 +0300
commit080a330e1d9142b9d958a40dcef3ae5ae5d8820a (patch)
tree269614c63b9b3984e26be51243da5101aba95d44 /fs/ceph
parentc8a96a31cb04c7664626ab6ada7f66c98c09efbd (diff)
downloadlinux-080a330e1d9142b9d958a40dcef3ae5ae5d8820a.tar.xz
ceph: present consistent fsid, regardless of arch endianness
Since its inception, ceph has presented the fsid as an opaque value without any sort of endianness conversion. This means that the value presented is different on architectures of different endianness. While the value that should be stuffed into f_fsid is poorly-defined, I think it would be best to strive for consistency here between architectures, and clients (we need to present this properly to the userland client as well). Change ceph_statfs to convert the opaque words to host-endian before doing the xor. On an upgrade, a big-endian box may see a different fsid than it did before, but little-endian arches should see no change with this patch. Signed-off-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Sage Weil <sage@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/super.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index e4082afedcb1..fe9fbb3f13f7 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -84,8 +84,9 @@ static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
buf->f_ffree = -1;
buf->f_namelen = NAME_MAX;
- /* leave fsid little-endian, regardless of host endianness */
- fsid = *(u64 *)(&monmap->fsid) ^ *((u64 *)&monmap->fsid + 1);
+ /* Must convert the fsid, for consistent values across arches */
+ fsid = le64_to_cpu(*(__le64 *)(&monmap->fsid)) ^
+ le64_to_cpu(*((__le64 *)&monmap->fsid + 1));
buf->f_fsid.val[0] = fsid & 0xffffffff;
buf->f_fsid.val[1] = fsid >> 32;