1 files changed, 16 insertions, 1 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 24310c9cb14f..00d59c6a9769 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6207,6 +6207,7 @@ static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *io
                         unsigned long nr_segs)
 {
         int seg;
+        int i;
         size_t size;
         unsigned long addr;
         unsigned blocksize_mask = root->sectorsize - 1;
@@ -6221,8 +6222,22 @@ static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *io
                 addr = (unsigned long)iov[seg].iov_base;
                 size = iov[seg].iov_len;
                 end += size;
-                if ((addr & blocksize_mask) || (size & blocksize_mask)) 
+                if ((addr & blocksize_mask) || (size & blocksize_mask))
                         goto out;
+
+                /* If this is a write we don't need to check anymore */
+                if (rw & WRITE)
+                        continue;
+
+                /*
+                 * Check to make sure we don't have duplicate iov_base's in this
+                 * iovec, if so return EINVAL, otherwise we'll get csum errors
+                 * when reading back.
+                 */
+                for (i = seg + 1; i < nr_segs; i++) {
+                        if (iov[seg].iov_base == iov[i].iov_base)
+                                goto out;
+                }
         }
         retval = 0;
 out: