udf: support 2048-byte spacing of VRS descriptors on 4K media

[linux.git] / fs / udf / super.c

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 14a91955507bf7d93a4bd716071c06bf594f95fb..f34e06b4d8fac0ee4614682694681aa6c1ed892a 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -739,6 +739,22 @@ static int udf_check_vsd(struct super_block *sb)
                vsd = (struct volStructDesc *)(bh->b_data +
                                              (sector & (sb->s_blocksize - 1)));
                nsr = identify_vsd(vsd);
+               /* Found NSR or end? */
+               if (nsr) {
+                       brelse(bh);
+                       break;
+               }
+               /*
+                * Special handling for improperly formatted VRS (e.g., Win10)
+                * where components are separated by 2048 bytes even though
+                * sectors are 4K
+                */
+               if (sb->s_blocksize == 4096) {
+                       nsr = identify_vsd(vsd + 1);
+                       /* Ignore unknown IDs... */
+                       if (nsr < 0)
+                               nsr = 0;
+               }
                brelse(bh);
        }