btrfs: zero out left over bytes after processing compression streams

[uclinux-h8/linux.git] / fs / btrfs / compression.c

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index d3220d3..dcd9be3 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1011,8 +1011,6 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
                bytes = min(bytes, working_bytes);
                kaddr = kmap_atomic(page_out);
                memcpy(kaddr + *pg_offset, buf + buf_offset, bytes);
-               if (*pg_index == (vcnt - 1) && *pg_offset == 0)
-                       memset(kaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
                kunmap_atomic(kaddr);
                flush_dcache_page(page_out);
 
@@ -1054,3 +1052,34 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
 
        return 1;
 }
+
+/*
+ * When uncompressing data, we need to make sure and zero any parts of
+ * the biovec that were not filled in by the decompression code.  pg_index
+ * and pg_offset indicate the last page and the last offset of that page
+ * that have been filled in.  This will zero everything remaining in the
+ * biovec.
+ */
+void btrfs_clear_biovec_end(struct bio_vec *bvec, int vcnt,
+                                  unsigned long pg_index,
+                                  unsigned long pg_offset)
+{
+       while (pg_index < vcnt) {
+               struct page *page = bvec[pg_index].bv_page;
+               unsigned long off = bvec[pg_index].bv_offset;
+               unsigned long len = bvec[pg_index].bv_len;
+
+               if (pg_offset < off)
+                       pg_offset = off;
+               if (pg_offset < off + len) {
+                       unsigned long bytes = off + len - pg_offset;
+                       char *kaddr;
+
+                       kaddr = kmap_atomic(page);
+                       memset(kaddr + pg_offset, 0, bytes);
+                       kunmap_atomic(kaddr);
+               }
+               pg_index++;
+               pg_offset = 0;
+       }
+}