imsm: retry load_imsm_mpb if we suspect mdmon has made modifications

If the checksum verification fails and mdmon is running we retry the
load to get a consistent snapshot of the mpb.  Found by
tests/08imsm-overlap.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/super-intel.c b/super-intel.c
index 3f83255ad3f06d2914a3a905731d3ed544785813..f55d707667b17baa47b31172eea02a8e8f78ffa6 100644 (file)
--- a/super-intel.c
+++ b/super-intel.c
@@ -1820,7 +1820,7 @@ static int load_imsm_mpb(int fd, struct intel_super *super, char *devname)
                                Name ": IMSM checksum %x != %x on %s\n",
                                check_sum, __le32_to_cpu(super->anchor->check_sum),
                                devname);
-               return 2;
+               return 3;
        }
 
        /* FIXME the BBM log is disk specific so we cannot use this global
@@ -1974,6 +1974,8 @@ static int load_super_imsm_all(struct supertype *st, int fd, void **sbp,
        char nm[20];
        int dfd;
        int rv;
+       int devnum = fd2devnum(fd);
+       int retry;
 
        /* check if this disk is a member of an active array */
        sra = sysfs_read(fd, 0, GET_LEVEL|GET_VERSION|GET_DEVS|GET_STATE);
@@ -1998,6 +2000,15 @@ static int load_super_imsm_all(struct supertype *st, int fd, void **sbp,
                        return 2;
                }
                rv = load_imsm_mpb(dfd, super, NULL);
+
+               /* retry the load if we might have raced against mdmon */
+               if (rv == 3 && mdmon_running(devnum))
+                       for (retry = 0; retry < 3; retry++) {
+                               usleep(3000);
+                               rv = load_imsm_mpb(dfd, super, NULL);
+                               if (rv != 3)
+                                       break;
+                       }
                if (!keep_fd)
                        close(dfd);
                if (rv == 0) {
@@ -2011,7 +2022,7 @@ static int load_super_imsm_all(struct supertype *st, int fd, void **sbp,
                        }
                } else {
                        free_imsm(super);
-                       return 2;
+                       return rv;
                }
        }
 
@@ -2061,7 +2072,7 @@ static int load_super_imsm_all(struct supertype *st, int fd, void **sbp,
        }
 
        *sbp = super;
-       st->container_dev = fd2devnum(fd);
+       st->container_dev = devnum;
        if (st->ss == NULL) {
                st->ss = &super_imsm;
                st->minor_version = 0;