FIX: Changes in '0' case for reshape position verification

Reading sysfs entry that is '0' long should cause an error.
Reshape position cannot be empty.

Absence of reshape position should be ignored. It is possible
that we are about raid0 reshape continuation and it is before takeover.
This means that according metadata (changed by mdmon) it should be reshaped
but md knows nothing about it at this moment. Reshape continuation
in reshape_array() will change it to raid4 and reshape position appears
in sysfs.

Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/Grow.c b/Grow.c
index 53a7cad72aca4256fda8a61efdf69adfba7c3b30..239b50d6bec08bcfd878277781e6f642218365a5 100644 (file)
--- a/Grow.c
+++ b/Grow.c
@@ -1876,9 +1876,12 @@ static int verify_reshape_position(struct mdinfo *info, int level)
 {
        int ret_val = 0;
        char buf[40];
+       int rv;
 
        /* read sync_max, failure can mean raid0 array */
-       if (sysfs_get_str(info, NULL, "sync_max", buf, 40) > 0) {
+       rv = sysfs_get_str(info, NULL, "sync_max", buf, 40);
+
+       if (rv > 0) {
                char *ep;
                unsigned long long position = strtoull(buf, &ep, 0);
 
@@ -1906,6 +1909,11 @@ static int verify_reshape_position(struct mdinfo *info, int level)
                                ret_val = 1;
                        }
                }
+       } else if (rv == 0) {
+               /* for valid sysfs entry, 0-length content
+                * should be indicated as error
+                */
+               ret_val = -1;
        }
 
        return ret_val;
@@ -3975,7 +3983,7 @@ int Grow_continue_command(char *devname, int fd,
         * correct position
         */
        if (verify_reshape_position(content,
-                                   map_name(pers, mdstat->level)) <= 0) {
+                                   map_name(pers, mdstat->level)) < 0) {
                ret_val = 1;
                goto Grow_continue_command_exit;
        }