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eCryptfs: Simplify lower file offset calculation

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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: Tyler Hicks <tyhicks@canonical.com>
This commit is contained in:
Tyler Hicks 2013-04-15 17:28:09 -07:00
parent 0f89617623
commit 24d15266bd
1 changed files with 7 additions and 11 deletions
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18
fs/ecryptfs/crypto.c
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@ -407,15 +407,15 @@ out:
}
/**
* 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);