From 24562486be76cf223b8d911f45e1d26eb3364b13 Mon Sep 17 00:00:00 2001 From: Frank Swiderski Date: Mon, 15 Nov 2010 10:43:22 -0800 Subject: ecryptfs: remove unnecessary decrypt when extending a file Removes an unecessary page decrypt from ecryptfs_begin_write when the page is beyond the current file size. Previously, the call to ecryptfs_decrypt_page would result in a read of 0 bytes, but still attempt to decrypt an entire page. This patch detects that case and merely zeros the page before marking it up-to-date. Signed-off-by: Frank Swiderski Signed-off-by: Tyler Hicks --- fs/ecryptfs/mmap.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 4b901139273..cc64fca89f8 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -290,6 +290,7 @@ static int ecryptfs_write_begin(struct file *file, return -ENOMEM; *pagep = page; + prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT); if (!PageUptodate(page)) { struct ecryptfs_crypt_stat *crypt_stat = &ecryptfs_inode_to_private(mapping->host)->crypt_stat; @@ -335,18 +336,23 @@ static int ecryptfs_write_begin(struct file *file, SetPageUptodate(page); } } else { - rc = ecryptfs_decrypt_page(page); - if (rc) { - printk(KERN_ERR "%s: Error decrypting page " - "at index [%ld]; rc = [%d]\n", - __func__, page->index, rc); - ClearPageUptodate(page); - goto out; + if (prev_page_end_size + >= i_size_read(page->mapping->host)) { + zero_user(page, 0, PAGE_CACHE_SIZE); + } else { + rc = ecryptfs_decrypt_page(page); + if (rc) { + printk(KERN_ERR "%s: Error decrypting " + "page at index [%ld]; " + "rc = [%d]\n", + __func__, page->index, rc); + ClearPageUptodate(page); + goto out; + } } SetPageUptodate(page); } } - prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT); /* If creating a page or more of holes, zero them out via truncate. * Note, this will increase i_size. */ if (index != 0) { -- cgit v1.2.3-70-g09d2