Btrfs already skip store of data where compression didn't free at least one 
byte.
So make logic better and make check that compression free at least one 
PAGE_SIZE,
because in another case it useless to store this data compressed

Signed-off-by: Timofey Titovets <nefelim...@gmail.com>
---
 fs/btrfs/lzo.c  | 5 ++++-
 fs/btrfs/zlib.c | 3 ++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index bd0b0938..39678499 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -229,8 +229,11 @@ static int lzo_compress_pages(struct list_head *ws,
                in_len = min(bytes_left, PAGE_SIZE);
        }

-       if (tot_out > tot_in)
+       /* Compression must save at least one PAGE_SIZE */
+       if (tot_out + PAGE_SIZE > tot_in) {
+               ret = -E2BIG;
                goto out;
+       }

        /* store the size of all chunks of compressed data */
        cpage_out = kmap(pages[0]);
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 135b1082..11e117b5 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -191,7 +191,8 @@ static int zlib_compress_pages(struct list_head *ws,
                goto out;
        }

-       if (workspace->strm.total_out >= workspace->strm.total_in) {
+       /* Compression must save at least one PAGE_SIZE */
+       if (workspace->strm.total_out + PAGE_SIZE > workspace->strm.total_in) {
                ret = -E2BIG;
                goto out;
        }
--
2.13.0
--
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