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| author | Frank Swiderski <fes@chromium.org> | 2010-11-15 10:43:22 -0800 |
|---|---|---|
| committer | Tyler Hicks <tyhicks@linux.vnet.ibm.com> | 2011-01-17 13:01:25 -0600 |
| commit | 24562486be76cf223b8d911f45e1d26eb3364b13 (patch) | |
| tree | 7ce33c533c12b4dc66d8afd836c7996d5769e325 /fs/ecryptfs/mmap.c | |
| parent | f24b38874e1e37bb70291bbc4c5c3c13f5f9dac8 (diff) | |
| download | linux-24562486be76cf223b8d911f45e1d26eb3364b13.tar.gz linux-24562486be76cf223b8d911f45e1d26eb3364b13.tar.bz2 linux-24562486be76cf223b8d911f45e1d26eb3364b13.zip | |
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 <fes@chromium.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Diffstat (limited to 'fs/ecryptfs/mmap.c')
| -rw-r--r-- | fs/ecryptfs/mmap.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 4b9011392736..cc64fca89f8d 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) { |