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authorJeff Layton <jlayton@kernel.org>2021-10-05 11:12:58 -0400
committerIlya Dryomov <idryomov@gmail.com>2021-11-08 03:29:52 +0100
commit8cfc0c7ed34f7929ce7e5d7c6eecf4d01ba89a84 (patch)
treec02fbc12c15eaca98eee0a01b303a374c9f3b3a5 /fs/ceph/super.c
parent631ed4b082872767412cda8a941af832f227335c (diff)
ceph: properly handle statfs on multifs setups
ceph_statfs currently stuffs the cluster fsid into the f_fsid field. This was fine when we only had a single filesystem per cluster, but now that we have multiples we need to use something that will vary between them. Change ceph_statfs to xor each 32-bit chunk of the fsid (aka cluster id) into the lower bits of the statfs->f_fsid. Change the lower bits to hold the fscid (filesystem ID within the cluster). That should give us a value that is guaranteed to be unique between filesystems within a cluster, and should minimize the chance of collisions between mounts of different clusters. URL: https://tracker.ceph.com/issues/52812 Reported-by: Sachin Prabhu <sprabhu@redhat.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph/super.c')
-rw-r--r--fs/ceph/super.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index f6cbbfcdf66d..bab61232dc5a 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -52,8 +52,7 @@ static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
struct ceph_fs_client *fsc = ceph_inode_to_client(d_inode(dentry));
struct ceph_mon_client *monc = &fsc->client->monc;
struct ceph_statfs st;
- u64 fsid;
- int err;
+ int i, err;
u64 data_pool;
if (fsc->mdsc->mdsmap->m_num_data_pg_pools == 1) {
@@ -99,12 +98,14 @@ static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
buf->f_namelen = NAME_MAX;
/* Must convert the fsid, for consistent values across arches */
+ buf->f_fsid.val[0] = 0;
mutex_lock(&monc->mutex);
- fsid = le64_to_cpu(*(__le64 *)(&monc->monmap->fsid)) ^
- le64_to_cpu(*((__le64 *)&monc->monmap->fsid + 1));
+ for (i = 0 ; i < sizeof(monc->monmap->fsid) / sizeof(__le32) ; ++i)
+ buf->f_fsid.val[0] ^= le32_to_cpu(((__le32 *)&monc->monmap->fsid)[i]);
mutex_unlock(&monc->mutex);
- buf->f_fsid = u64_to_fsid(fsid);
+ /* fold the fs_cluster_id into the upper bits */
+ buf->f_fsid.val[1] = monc->fs_cluster_id;
return 0;
}