eCryptfs: Fix metadata in xattr feature regression

Fixes regression in 8faece5f906725c10e7a1f6caf84452abadbdc7b

When using the ecryptfs_xattr_metadata mount option, eCryptfs stores the
metadata (normally stored at the front of the file) in the user.ecryptfs
xattr.  This causes ecryptfs_crypt_stat.num_header_bytes_at_front to be
0, since there is no header data at the front of the file.  This results
in too much memory being requested and ENOMEM being returned from
ecryptfs_write_metadata().

This patch fixes the problem by using the num_header_bytes_at_front
variable for specifying the max size of the metadata, despite whether it
is stored in the header or xattr.

Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 7cb0a59f4b9d..c907f6f49351 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -381,8 +381,8 @@ out:
 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
                                              struct ecryptfs_crypt_stat *crypt_stat)
 {
-        (*offset) = (crypt_stat->num_header_bytes_at_front
-                     + (crypt_stat->extent_size * extent_num));
+        (*offset) = ecryptfs_lower_header_size(crypt_stat)
+                    + (crypt_stat->extent_size * extent_num);
 }
 
 /**
@@ -834,7 +834,8 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
         set_extent_mask_and_shift(crypt_stat);
         crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
-                crypt_stat->num_header_bytes_at_front = 0;
+                crypt_stat->num_header_bytes_at_front =
+                                        ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
         else {
                 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
                         crypt_stat->num_header_bytes_at_front =