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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/zlib.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/zlib.c')
-rw-r--r--fs/btrfs/zlib.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 759fa4e2de8f..fb22fd8d8fb8 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -299,6 +299,8 @@ done:
zlib_inflateEnd(&workspace->strm);
if (data_in)
kunmap(pages_in[page_in_index]);
+ if (!ret)
+ btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
return ret;
}
@@ -310,10 +312,14 @@ static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0;
int wbits = MAX_WBITS;
- unsigned long bytes_left = destlen;
+ unsigned long bytes_left;
unsigned long total_out = 0;
+ unsigned long pg_offset = 0;
char *kaddr;
+ destlen = min_t(unsigned long, destlen, PAGE_SIZE);
+ bytes_left = destlen;
+
workspace->strm.next_in = data_in;
workspace->strm.avail_in = srclen;
workspace->strm.total_in = 0;
@@ -341,7 +347,6 @@ static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
unsigned long buf_start;
unsigned long buf_offset;
unsigned long bytes;
- unsigned long pg_offset = 0;
ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END)
@@ -384,6 +389,17 @@ next:
ret = 0;
zlib_inflateEnd(&workspace->strm);
+
+ /*
+ * this should only happen if zlib returned fewer bytes than we
+ * expected. btrfs_get_block is responsible for zeroing from the
+ * end of the inline extent (destlen) to the end of the page
+ */
+ if (pg_offset < destlen) {
+ kaddr = kmap_atomic(dest_page);
+ memset(kaddr + pg_offset, 0, destlen - pg_offset);
+ kunmap_atomic(kaddr);
+ }
return ret;
}