b=23289 disable RS_DEBUG by default

[fs/lustre-release.git] / lustre / include / lustre_fid.h

diff --git a/lustre/include/lustre_fid.h b/lustre/include/lustre_fid.h
index 9311d40..f31c4b5 100644 (file)
--- a/lustre/include/lustre_fid.h
+++ b/lustre/include/lustre_fid.h
@@ -369,8 +369,16 @@ static inline __u32 fid_flatten32(const struct lu_fid *fid)
 
         seq = fid_seq(fid) - FID_SEQ_START;
 
-        ino = ((seq & 0xfffffULL) << 12) + ((seq >> 8) & 0xfffff000) +
-                (seq >> (64 - (40-8)) & 0xffffff00) + fid_oid(fid);
+       /*
+          map the high bits of the OID into higher bits of the inode number so that
+          inodes generated at about the same time have a reduced chance of collisions.
+          This will give a period of 1024 clients and 128 k = 128M inodes without collisions.
+       */
+
+        ino = ((seq & 0x000fffffULL) << 12) + ((seq >> 8) & 0xfffff000) +
+               (seq >> (64 - (40-8)) & 0xffffff00) +
+               (fid_oid(fid) & 0xff000fff) + ((fid_oid(fid) & 0x00fff000) << 16);
+
         RETURN(ino ? ino : fid_oid(fid));
 }