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Commit 0f896176 authored by Tyler Hicks's avatar Tyler Hicks
Browse files

eCryptfs: Read/write entire page during page IO 



When reading and writing encrypted pages, perform IO using the entire
page all at once rather than 4096 bytes at a time.

This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.

Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
parent 12003e5b

fs/ecryptfs/crypto.c

+31 −35
Original line number Diff line number Diff line
@@ -490,6 +490,7 @@ int ecryptfs_encrypt_page(struct page *page) 
	char *enc_extent_virt;

	struct page *enc_extent_page = NULL;

	loff_t extent_offset;

	loff_t lower_offset;

	int rc = 0;



	ecryptfs_inode = page->mapping->host;
@@ -503,12 +504,10 @@ int ecryptfs_encrypt_page(struct page *page) 
				"encrypted extent\n");

		goto out;

	}

	enc_extent_virt = kmap(enc_extent_page);



	for (extent_offset = 0;

	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);

	     extent_offset++) {

		loff_t offset;



		rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,

					     extent_offset);

		if (rc) {
@@ -516,25 +515,24 @@ int ecryptfs_encrypt_page(struct page *page) 
			       "rc = [%d]\n", __func__, rc);

			goto out;

		}

		ecryptfs_lower_offset_for_extent(

			&offset, ((((loff_t)page->index)

				   * (PAGE_CACHE_SIZE

				      / crypt_stat->extent_size))

				  + extent_offset), crypt_stat);

		rc = ecryptfs_write_lower(ecryptfs_inode, (enc_extent_virt +

				extent_offset * crypt_stat->extent_size),

				offset, crypt_stat->extent_size);

	}



	ecryptfs_lower_offset_for_extent(&lower_offset,

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

		crypt_stat);

	enc_extent_virt = kmap(enc_extent_page);

	rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,

				  PAGE_CACHE_SIZE);

	kunmap(enc_extent_page);

	if (rc < 0) {

			ecryptfs_printk(KERN_ERR, "Error attempting "

					"to write lower page; rc = [%d]"

					"\n", rc);

		ecryptfs_printk(KERN_ERR,

			"Error attempting to write lower page; rc = [%d]\n",

			rc);

		goto out;

	}

	}

	rc = 0;

out:

	if (enc_extent_page) {

		kunmap(enc_extent_page);

		__free_page(enc_extent_page);

	}

	return rc;
@@ -599,6 +597,7 @@ int ecryptfs_decrypt_page(struct page *page) 
	char *enc_extent_virt;

	struct page *enc_extent_page = NULL;

	unsigned long extent_offset;

	loff_t lower_offset;

	int rc = 0;



	ecryptfs_inode = page->mapping->host;
@@ -612,26 +611,24 @@ int ecryptfs_decrypt_page(struct page *page) 
				"encrypted extent\n");

		goto out;

	}



	ecryptfs_lower_offset_for_extent(&lower_offset,

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

		crypt_stat);

	enc_extent_virt = kmap(enc_extent_page);

	for (extent_offset = 0;

	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);

	     extent_offset++) {

		loff_t offset;



		ecryptfs_lower_offset_for_extent(

			&offset, ((page->index * (PAGE_CACHE_SIZE

						  / crypt_stat->extent_size))

				  + extent_offset), crypt_stat);

		rc = ecryptfs_read_lower((enc_extent_virt +

				extent_offset * crypt_stat->extent_size),

				offset, crypt_stat->extent_size,

	rc = ecryptfs_read_lower(enc_extent_virt, lower_offset, PAGE_CACHE_SIZE,

				 ecryptfs_inode);

	kunmap(enc_extent_page);

	if (rc < 0) {

			ecryptfs_printk(KERN_ERR, "Error attempting "

					"to read lower page; rc = [%d]"

					"\n", rc);

		ecryptfs_printk(KERN_ERR,

			"Error attempting to read lower page; rc = [%d]\n",

			rc);

		goto out;

	}



	for (extent_offset = 0;

	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);

	     extent_offset++) {

		rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,

					     extent_offset);

		if (rc) {
@@ -642,7 +639,6 @@ int ecryptfs_decrypt_page(struct page *page) 
	}

out:

	if (enc_extent_page) {

		kunmap(enc_extent_page);

		__free_page(enc_extent_page);

	}

	return rc;