fix spelling in block sub directory

Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

block/cow.c

@@ -92,7 +92,7 @@ static int cow_open(BlockDriverState *bs, int flags)
 }
 
 /*
- * XXX(hch): right now these functions are extremly ineffcient.
+ * XXX(hch): right now these functions are extremely ineffcient.
  * We should just read the whole bitmap we'll need in one go instead.
  */
 static inline int cow_set_bit(BlockDriverState *bs, int64_t bitnum)

block/qcow2.c

@@ -92,7 +92,7 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
         if (offset > s->cluster_size)
             printf("qcow2_read_extension: suspicious offset %lu\n", offset);
 
-        printf("attemting to read extended header in offset %lu\n", offset);
+        printf("attempting to read extended header in offset %lu\n", offset);
 #endif
 
         if (bdrv_pread(bs->file, offset, &ext, sizeof(ext)) != sizeof(ext)) {
@@ -821,7 +821,7 @@ static int qcow2_create2(const char *filename, int64_t total_size,
                          int flags, size_t cluster_size, int prealloc,
                          QEMUOptionParameter *options)
 {
-    /* Calulate cluster_bits */
+    /* Calculate cluster_bits */
     int cluster_bits;
     cluster_bits = ffs(cluster_size) - 1;
     if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||

block/raw-posix.c

@@ -1153,7 +1153,7 @@ static int cdrom_open(BlockDriverState *bs, const char *filename, int flags)
     if (ret)
         return ret;
 
-    /* make sure the door isnt locked at this time */
+    /* make sure the door isn't locked at this time */
     ioctl(s->fd, CDIOCALLOW);
     return 0;
 }
@@ -1184,7 +1184,7 @@ static int cdrom_reopen(BlockDriverState *bs)
     }
     s->fd = fd;
 
-    /* make sure the door isnt locked at this time */
+    /* make sure the door isn't locked at this time */
     ioctl(s->fd, CDIOCALLOW);
     return 0;
 }