LU-2441 mdd: Implement volatile file

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

diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index 3455924..cdf0a5f 100644 (file)
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -1746,4 +1746,46 @@ static inline const char *lu_dev_name(const struct lu_device *lu_dev)
         return lu_dev->ld_obd->obd_name;
 }
 
+static inline bool filename_is_volatile(const char *name, int namelen, int *idx)
+{
+       const char      *start;
+       char            *end;
+
+       if (strncmp(name, LUSTRE_VOLATILE_HDR, LUSTRE_VOLATILE_HDR_LEN) != 0)
+               return false;
+
+       /* caller does not care of idx */
+       if (idx == NULL)
+               return true;
+
+       /* volatile file, the MDT can be set from name */
+       /* name format is LUSTRE_VOLATILE_HDR:[idx]: */
+       /* if no MDT is specified, use std way */
+       if (namelen < LUSTRE_VOLATILE_HDR_LEN + 2)
+               goto bad_format;
+       /* test for no MDT idx case */
+       if ((*(name + LUSTRE_VOLATILE_HDR_LEN) == ':') &&
+           (*(name + LUSTRE_VOLATILE_HDR_LEN + 1) == ':')) {
+               *idx = -1;
+               return true;
+       }
+       /* we have an idx, read it */
+       start = name + LUSTRE_VOLATILE_HDR_LEN + 1;
+       *idx = strtoul(start, &end, 0);
+       /* error cases:
+        * no digit, no trailing :, negative value
+        */
+       if (((*idx == 0) && (end == start)) ||
+           (*end != ':') || (*idx < 0))
+               goto bad_format;
+
+       return true;
+bad_format:
+       /* bad format of mdt idx, we cannot return an error
+        * to caller so we use hash algo */
+       CERROR("Bad volatile file name format: %s\n",
+              name + LUSTRE_VOLATILE_HDR_LEN);
+       return false;
+}
+
 #endif /* __OBD_H */