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-rw-r--r--fs/ceph/super.h24
1 files changed, 24 insertions, 0 deletions
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index df0851b9240e..db80d89556b1 100644
--- 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