Grow: avoid overflow of chunk sizes.

Chunks aren't particularly big, but when you could them in bytes
and multiply them together (as we do for calculating the backup
size for 'grow') they can overflow a 32bit int.

So group the division by 512 more closely with the
chunk size so were would need 30Meg chunks to come close to
overflowing 32bits.

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

diff --git a/Grow.c b/Grow.c
index 053a372ac3b526f7a5b5cccce6955f02735914ea..0916c5de236e5260827b812509a64181df7c8942 100644 (file)
--- a/Grow.c
+++ b/Grow.c
@@ -931,8 +931,8 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
                 * old stripes and a whole number of new stripes.
                 * So LCM for (chunksize*datadisks).
                 */
-               a = ochunk/512 * odata;
-               b = nchunk/512 * ndata;
+               a = (ochunk/512) * odata;
+               b = (nchunk/512) * ndata;
                /* Find GCD */
                while (a != b) {
                        if (a < b)
@@ -941,7 +941,7 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
                                a -= b;
                }
                /* LCM == product / GCD */
-               blocks = ochunk/512 * nchunk/512 * odata * ndata / a;
+               blocks = (ochunk/512) * (nchunk/512) * odata * ndata / a;
 
                sysfs_free(sra);
                sra = sysfs_read(fd, 0,
@@ -1284,7 +1284,7 @@ int grow_backup(struct mdinfo *sra,
                odata--;
        if (level == 6)
                odata--;
-       sysfs_set_num(sra, NULL, "suspend_hi", (offset + stripes * chunk/512) * odata);
+       sysfs_set_num(sra, NULL, "suspend_hi", (offset + stripes * (chunk/512)) * odata);
        /* Check that array hasn't become degraded, else we might backup the wrong data */
        sysfs_get_ll(sra, NULL, "degraded", &new_degraded);
        if (new_degraded != *degraded) {
@@ -1312,10 +1312,10 @@ int grow_backup(struct mdinfo *sra,
        }
        if (part) {
                bsb.arraystart2 = __cpu_to_le64(offset * odata);
-               bsb.length2 = __cpu_to_le64(stripes * chunk/512 * odata);
+               bsb.length2 = __cpu_to_le64(stripes * (chunk/512) * odata);
        } else {
                bsb.arraystart = __cpu_to_le64(offset * odata);
-               bsb.length = __cpu_to_le64(stripes * chunk/512 * odata);
+               bsb.length = __cpu_to_le64(stripes * (chunk/512) * odata);
        }
        if (part)
                bsb.magic[15] = '2';
@@ -1540,10 +1540,10 @@ static int child_grow(int afd, struct mdinfo *sra, unsigned long stripes,
                    dests, destfd, destoffsets,
                    0, &degraded, buf);
        validate(afd, destfd[0], destoffsets[0]);
-       wait_backup(sra, 0, stripes * chunk / 512, stripes * chunk / 512,
+       wait_backup(sra, 0, stripes * (chunk / 512), stripes * (chunk / 512),
                    dests, destfd, destoffsets,
                    0);
-       sysfs_set_num(sra, NULL, "suspend_lo", (stripes * chunk/512) * data);
+       sysfs_set_num(sra, NULL, "suspend_lo", (stripes * (chunk/512)) * data);
        free(buf);
        /* FIXME this should probably be numeric */
        sysfs_set_str(sra, NULL, "sync_max", "max");
@@ -1562,12 +1562,12 @@ static int child_shrink(int afd, struct mdinfo *sra, unsigned long stripes,
 
        if (posix_memalign((void**)&buf, 4096, disks * chunk))
                return 0;
-       start = sra->component_size - stripes * chunk/512;
+       start = sra->component_size - stripes * (chunk/512);
        sysfs_set_num(sra, NULL, "sync_max", start);
        sysfs_set_str(sra, NULL, "sync_action", "reshape");
        sysfs_set_num(sra, NULL, "suspend_lo", 0);
        sysfs_set_num(sra, NULL, "suspend_hi", 0);
-       rv = wait_backup(sra, 0, start - stripes * chunk/512, stripes * chunk/512,
+       rv = wait_backup(sra, 0, start - stripes * (chunk/512), stripes * (chunk/512),
                         dests, destfd, destoffsets, 0);
        if (rv < 0)
                return 0;
@@ -1577,9 +1577,9 @@ static int child_shrink(int afd, struct mdinfo *sra, unsigned long stripes,
                    dests, destfd, destoffsets,
                    0, &degraded, buf);
        validate(afd, destfd[0], destoffsets[0]);
-       wait_backup(sra, start, stripes*chunk/512, 0,
+       wait_backup(sra, start, stripes*(chunk/512), 0,
                    dests, destfd, destoffsets, 0);
-       sysfs_set_num(sra, NULL, "suspend_lo", (stripes * chunk/512) * data);
+       sysfs_set_num(sra, NULL, "suspend_lo", (stripes * (chunk/512)) * data);
        free(buf);
        /* FIXME this should probably be numeric */
        sysfs_set_str(sra, NULL, "sync_max", "max");
@@ -1614,7 +1614,7 @@ static int child_same_size(int afd, struct mdinfo *sra, unsigned long stripes,
                    disks, chunk, level, layout,
                    dests, destfd, destoffsets,
                    0, &degraded, buf);
-       grow_backup(sra, (start + stripes) * chunk/512, stripes,
+       grow_backup(sra, (start + stripes) * (chunk/512), stripes,
                    fds, offsets,
                    disks, chunk, level, layout,
                    dests, destfd, destoffsets,
@@ -1624,16 +1624,16 @@ static int child_same_size(int afd, struct mdinfo *sra, unsigned long stripes,
        start += stripes * 2; /* where to read next */
        size = sra->component_size / (chunk/512);
        while (start < size) {
-               if (wait_backup(sra, (start-stripes*2)*chunk/512,
-                               stripes*chunk/512, 0,
+               if (wait_backup(sra, (start-stripes*2)*(chunk/512),
+                               stripes*(chunk/512), 0,
                                dests, destfd, destoffsets,
                                part) < 0)
                        return 0;
-               sysfs_set_num(sra, NULL, "suspend_lo", start*chunk/512 * data);
+               sysfs_set_num(sra, NULL, "suspend_lo", start*(chunk/512) * data);
                if (start + stripes > size)
                        tailstripes = (size - start);
 
-               grow_backup(sra, start*chunk/512, tailstripes,
+               grow_backup(sra, start*(chunk/512), tailstripes,
                            fds, offsets,
                            disks, chunk, level, layout,
                            dests, destfd, destoffsets,
@@ -1642,15 +1642,15 @@ static int child_same_size(int afd, struct mdinfo *sra, unsigned long stripes,
                part = 1 - part;
                validate(afd, destfd[0], destoffsets[0]);
        }
-       if (wait_backup(sra, (start-stripes*2) * chunk/512, stripes * chunk/512, 0,
+       if (wait_backup(sra, (start-stripes*2) * (chunk/512), stripes * (chunk/512), 0,
                        dests, destfd, destoffsets,
                        part) < 0)
                return 0;
-       sysfs_set_num(sra, NULL, "suspend_lo", ((start-stripes)*chunk/512) * data);
-       wait_backup(sra, (start-stripes) * chunk/512, tailstripes * chunk/512, 0,
+       sysfs_set_num(sra, NULL, "suspend_lo", ((start-stripes)*(chunk/512)) * data);
+       wait_backup(sra, (start-stripes) * (chunk/512), tailstripes * (chunk/512), 0,
                    dests, destfd, destoffsets,
                    1-part);
-       sysfs_set_num(sra, NULL, "suspend_lo", (size*chunk/512) * data);
+       sysfs_set_num(sra, NULL, "suspend_lo", (size*(chunk/512)) * data);
        sysfs_set_num(sra, NULL, "sync_speed_min", speed);
        free(buf);
        return 1;
@@ -1991,8 +1991,8 @@ int Grow_continue(int mdfd, struct supertype *st, struct mdinfo *info,
        nchunk = info->new_chunk;
 
 
-       a = ochunk/512 * odata;
-       b = nchunk/512 * ndata;
+       a = (ochunk/512) * odata;
+       b = (nchunk/512) * ndata;
        /* Find GCD */
        while (a != b) {
                if (a < b)
@@ -2001,7 +2001,7 @@ int Grow_continue(int mdfd, struct supertype *st, struct mdinfo *info,
                        a -= b;
        }
        /* LCM == product / GCD */
-       blocks = ochunk/512 * nchunk/512 * odata * ndata / a;
+       blocks = (ochunk/512) * (nchunk/512) * odata * ndata / a;
 
        sra = sysfs_read(-1, devname2devnum(info->sys_name),
                         GET_COMPONENT|GET_DEVS|GET_OFFSET|GET_STATE|