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authorChris Mason <clm@fb.com>2014-11-30 16:56:33 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2014-11-30 20:33:51 +0300
commit2f19cad94cee3c9bd52d0c9ca584ef506302fb7c (patch)
treeca1a69874842c86904ff6b66cb7430c818f2baa4 /fs/btrfs/compression.c
parent7a5a4f978750756755dc839014e13d1b088ccc8e (diff)
downloadlinux-2f19cad94cee3c9bd52d0c9ca584ef506302fb7c.tar.xz
btrfs: zero out left over bytes after processing compression streams
Don Bailey noticed that our page zeroing for compression at end-io time isn't complete. This reworks a patch from Linus to push the zeroing into the zlib and lzo specific functions instead of trying to handle the corners inside btrfs_decompress_buf2page Signed-off-by: Chris Mason <clm@fb.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Reported-by: Don A. Bailey <donb@securitymouse.com> cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/btrfs/compression.c')
-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;
+ }
+}