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;
 }