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-rw-r--r--fs/btrfs/compression.c33
1 files changed, 31 insertions, 2 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index d3220d31d3cb..dcd9be32ac57 100644
--- 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;
+ }
+}