Assemble: improve efficacy of -Af in assembling degraded dirty arrays.

If a degraded dirty array has some superblocks which are clean and
others that are dirty, and the dirty ones are newer by precisely '1'
in the event count, then the current code to force the array to be
clean will not work.
We need to make sure to find a superblock with most recent event count
and force that one to be 'clean'.

Reported-by: A J Wyborny <ajwyborny@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/Assemble.c b/Assemble.c
index ea3a6484d9ad78ac8977a0efa02e686c9662324b..83bdbfac953fb67dbd07eac33ef7e3db08bc6141 100644 (file)
--- a/Assemble.c
+++ b/Assemble.c
@@ -905,6 +905,8 @@ int Assemble(struct supertype *st, char *mddev,
                        continue;
                if (!devices[j].uptodate)
                        continue;
+               if (devices[j].i.events < devices[most_recent].i.events)
+                       continue;
                chosen_drive = j;
                if ((fd=dev_open(devices[j].devname, O_RDONLY|O_EXCL))< 0) {
                        fprintf(stderr, Name ": Cannot open %s: %s\n",
@@ -996,6 +998,9 @@ int Assemble(struct supertype *st, char *mddev,
                        close(mdfd);
                        return 1;
                }
+               if (verbose >= 0)
+                       fprintf(stderr, Name ": Marking array %s as 'clean'\n",
+                               mddev);
                close(fd);
        }