ceph: don't allow access to MDS-private inodes

[linux-2.6-microblaze.git] / fs / ceph / super.h

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index df0851b..db80d89 100644 (file)
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -529,10 +529,34 @@ static inline int ceph_ino_compare(struct inode *inode, void *data)
                ci->i_vino.snap == pvino->snap;
 }
 
+/*
+ * The MDS reserves a set of inodes for its own usage. These should never
+ * be accessible by clients, and so the MDS has no reason to ever hand these
+ * out. The range is CEPH_MDS_INO_MDSDIR_OFFSET..CEPH_INO_SYSTEM_BASE.
+ *
+ * These come from src/mds/mdstypes.h in the ceph sources.
+ */
+#define CEPH_MAX_MDS           0x100
+#define CEPH_NUM_STRAY         10
+#define CEPH_MDS_INO_MDSDIR_OFFSET     (1 * CEPH_MAX_MDS)
+#define CEPH_INO_SYSTEM_BASE           ((6*CEPH_MAX_MDS) + (CEPH_MAX_MDS * CEPH_NUM_STRAY))
+
+static inline bool ceph_vino_is_reserved(const struct ceph_vino vino)
+{
+       if (vino.ino < CEPH_INO_SYSTEM_BASE &&
+           vino.ino >= CEPH_MDS_INO_MDSDIR_OFFSET) {
+               WARN_RATELIMIT(1, "Attempt to access reserved inode number 0x%llx", vino.ino);
+               return true;
+       }
+       return false;
+}
 
 static inline struct inode *ceph_find_inode(struct super_block *sb,
                                            struct ceph_vino vino)
 {
+       if (ceph_vino_is_reserved(vino))
+               return NULL;
+
        /*
         * NB: The hashval will be run through the fs/inode.c hash function
         * anyway, so there is no need to squash the inode number down to