super1: make aread/awrite always use an aligned buffer.

A recently change to write_bitmap1 meant awrite would sometimes
write from a non-aligned buffer which of course break.

So change awrite (and aread) to always use their own aligned
buffer to ensure safety.

Reported-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/super1.c b/super1.c
index d23d6e8e5464ebd734c35a884066ea482b2d8650..cfa237a0d6b309c9aa38a1320aa6d6c8a49588e1 100644 (file)
--- a/super1.c
+++ b/super1.c
@@ -143,17 +143,19 @@ static int aread(int fd, void *buf, int len)
         * the full sector and copy relevant bits into
         * the buffer
         */
-       int bsize;
+       int bsize, iosize;
        char *b;
        int n;
-       if (ioctl(fd, BLKSSZGET, &bsize) != 0 ||
-           bsize <= len)
-               return read(fd, buf, len);
-       if (bsize > 4096)
+       if (ioctl(fd, BLKSSZGET, &bsize) != 0)
+               bsize = 512;
+
+       if (bsize > 4096 || len > 4096)
                return -1;
        b = (char*)(((long)(abuf+4096))&~4095UL);
 
-       n = read(fd, b, bsize);
+       for (iosize = 0; iosize < len; iosize += bsize)
+               ;
+       n = read(fd, b, iosize);
        if (n <= 0)
                return n;
        lseek(fd, len - n, 1);
@@ -171,22 +173,27 @@ static int awrite(int fd, void *buf, int len)
         * than the write.
         * The address must be sector-aligned.
         */
-       int bsize;
+       int bsize, iosize;
        char *b;
        int n;
-       if (ioctl(fd, BLKSSZGET, &bsize) != 0 ||
-           bsize <= len)
-               return write(fd, buf, len);
-       if (bsize > 4096)
+       if (ioctl(fd, BLKSSZGET, &bsize) != 0)
+               bsize = 512;
+       if (bsize > 4096 || len > 4096)
                return -1;
        b = (char*)(((long)(abuf+4096))&~4095UL);
 
-       n = read(fd, b, bsize);
-       if (n <= 0)
-               return n;
-       lseek(fd, -n, 1);
+       for (iosize = 0; iosize < len ; iosize += bsize)
+               ;
+
+       if (len != iosize) {
+               n = read(fd, b, iosize);
+               if (n <= 0)
+                       return n;
+               lseek(fd, -n, 1);
+       }
+
        memcpy(b, buf, len);
-       n = write(fd, b, bsize);
+       n = write(fd, b, iosize);
        if (n <= 0)
                return n;
        lseek(fd, len - n, 1);