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, 5 insertions, 14 deletions

diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index df4ce99d0597..5a30e01547f1 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -97,19 +97,6 @@ out:
  *                        (big-endian)
  *     Octet  26:         Begin RFC 2440 authentication token packet set
  */
-static void set_header_info(char *page_virt,
-                            struct ecryptfs_crypt_stat *crypt_stat)
-{
-        size_t written;
-        size_t save_num_header_bytes_at_front =
-                crypt_stat->num_header_bytes_at_front;
-
-        crypt_stat->num_header_bytes_at_front =
-                ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
-        ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
-        crypt_stat->num_header_bytes_at_front =
-                save_num_header_bytes_at_front;
-}
 
 /**
  * ecryptfs_copy_up_encrypted_with_header
@@ -146,9 +133,13 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page,
                         memset(page_virt, 0, PAGE_CACHE_SIZE);
                         /* TODO: Support more than one header extent */
                         if (view_extent_num == 0) {
+                                size_t written;
+
                                 rc = ecryptfs_read_xattr_region(
                                         page_virt, page->mapping->host);
-                                set_header_info(page_virt, crypt_stat);
+                                ecryptfs_write_header_metadata(page_virt + 20,
+                                                               crypt_stat,
+                                                               &written);
                         }
                         kunmap_atomic(page_virt, KM_USER0);
                         flush_dcache_page(page);