Commit 24d15266 authored by Tyler Hicks's avatar Tyler Hicks
Browse files

eCryptfs: Simplify lower file offset calculation 



Now that lower filesystem IO operations occur for complete
PAGE_CACHE_SIZE bytes, the calculation for converting an eCryptfs extent
index into a lower file offset can be simplified.

Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
parent 0f896176

fs/ecryptfs/crypto.c

+7 −11
Original line number Diff line number Diff line
@@ -407,15 +407,15 @@ static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, 
}



/**

 * ecryptfs_lower_offset_for_extent

 * lower_offset_for_page

 *

 * Convert an eCryptfs page index into a lower byte offset

 */

static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,

					     struct ecryptfs_crypt_stat *crypt_stat)

static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,

				    struct page *page)

{

	(*offset) = ecryptfs_lower_header_size(crypt_stat)

		    + (crypt_stat->extent_size * extent_num);

	return ecryptfs_lower_header_size(crypt_stat) +

	       (page->index << PAGE_CACHE_SHIFT);

}



/**
@@ -517,9 +517,7 @@ int ecryptfs_encrypt_page(struct page *page) 
		}

	}



	ecryptfs_lower_offset_for_extent(&lower_offset,

		page->index * (PAGE_CACHE_SIZE / crypt_stat->extent_size),

		crypt_stat);

	lower_offset = lower_offset_for_page(crypt_stat, page);

	enc_extent_virt = kmap(enc_extent_page);

	rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,

				  PAGE_CACHE_SIZE);
@@ -612,9 +610,7 @@ int ecryptfs_decrypt_page(struct page *page) 
		goto out;

	}



	ecryptfs_lower_offset_for_extent(&lower_offset,

		page->index * (PAGE_CACHE_SIZE / crypt_stat->extent_size),

		crypt_stat);

	lower_offset = lower_offset_for_page(crypt_stat, page);

	enc_extent_virt = kmap(enc_extent_page);

	rc = ecryptfs_read_lower(enc_extent_virt, lower_offset, PAGE_CACHE_SIZE,

				 ecryptfs_inode);