Factor out is_bare test.

Instead of open coding (and using horrible gotos), make this
a separate function.

Also fix the check for end of device - SEEK_END doesn't work on
block devices.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/Incremental.c b/Incremental.c
index 7b43963c1da2fbab7d35f58a2ae0c92a732b600a..35ad221ad9570c5a39debeef0c7ebc71fc5d66d4 100644 (file)
--- a/Incremental.c
+++ b/Incremental.c
@@ -1030,6 +1030,34 @@ static int partition_try_spare(char *devname, int *dfdp, struct dev_policy *pol,
        return 0;
 }
 
+static int is_bare(int dfd)
+{
+       unsigned long long size = 0;
+       char bufpad[4096 + 4096];
+       char *buf = (char*)(((long)bufpad + 4096) & ~4095);
+
+       if (lseek(dfd, 0, SEEK_SET) != 0 ||
+           read(dfd, buf, 4096) != 4096)
+               return 0;
+
+       if (buf[0] != '\0' && buf[0] != '\x5a' && buf[0] != '\xff')
+               return 0;
+       if (memcmp(buf, buf+1, 4095) != 0)
+               return 0;
+
+       /* OK, first 4K appear blank, try the end. */
+       get_dev_size(dfd, NULL, &size);
+       if (lseek(dfd, size-4096, SEEK_SET) < 0 ||
+           read(dfd, buf, 4096) != 4096)
+               return 0;
+
+       if (buf[0] != '\0' && buf[0] != '\x5a' && buf[0] != '\xff')
+               return 0;
+       if (memcmp(buf, buf+1, 4095) != 0)
+               return 0;
+
+       return 1;
+}
 
 /* adding a spare to a regular array is quite different from adding one to
  * a set-of-partitions virtual array.
@@ -1043,8 +1071,6 @@ static int try_spare(char *devname, int *dfdp, struct dev_policy *pol,
        int rv;
        int arrays_ok = 0;
        int partitions_ok = 0;
-       char bufpad[4096 + 4096];
-       char *buf = (char*)(((long)bufpad + 4096) & ~4095);
        int dfd = *dfdp;
 
        /* Can only add a spare if device has at least one domains */
@@ -1058,28 +1084,12 @@ static int try_spare(char *devname, int *dfdp, struct dev_policy *pol,
         * yet even if action=-spare
         */
 
-       if (lseek(dfd, 0, SEEK_SET) != 0 ||
-           read(dfd, buf, 4096) != 4096) {
-       not_bare:
+       if (!is_bare(dfd)) {
                if (verbose > 1)
                        fprintf(stderr, Name ": %s is not bare, so not considering as a spare\n",
                                devname);
                return 1;
        }
-       if (buf[0] != '\0' && buf[0] != '\x5a' && buf[0] != '\xff')
-               goto not_bare;
-       if (memcmp(buf, buf+1, 4095) != 0)
-               goto not_bare;
-
-       /* OK, first 4K appear blank, try the end. */
-       if (lseek(dfd, -4096, SEEK_END) < 0 ||
-           read(dfd, buf, 4096) != 4096)
-               goto not_bare;
-
-       if (buf[0] != '\0' && buf[0] != '\x5a' && buf[0] != '\xff')
-               goto not_bare;
-       if (memcmp(buf, buf+1, 4095) != 0)
-               goto not_bare;
 
        /* This device passes our test for 'is bare'.
         * Let's see what policy allows for such things.