eCryptfs: remove unnecessary page decrypt call

The page decrypt calls in ecryptfs_write() are both pointless and buggy.
Pointless because ecryptfs_get_locked_page() has already brought the page
up to date, and buggy because prior mmap writes will just be blown away by
the decrypt call.

This patch also removes the declaration of a now-nonexistent function
ecryptfs_write_zeros().

Thanks to Eric Sandeen and David Kleikamp for helping to track this
down.

Eric said:

   fsx w/ mmap dies quickly ( < 100 ops) without this, and survives
   nicely (to millions of ops+) with it in place.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 0 insertions, 24 deletions

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 951ee33a022d..c15c25745e05 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -660,8 +660,6 @@ int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
                                       struct ecryptfs_auth_tok **auth_tok,
                                       char *sig);
-int ecryptfs_write_zeros(struct file *file, pgoff_t index, int start,
-                         int num_zeros);
 int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
                          loff_t offset, size_t size);
 int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index ebf55150be56..75c2ea9fee35 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -157,20 +157,6 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
                                ecryptfs_page_idx, rc);
                         goto out;
                 }
-                if (start_offset_in_page) {
-                        /* Read in the page from the lower
-                         * into the eCryptfs inode page cache,
-                         * decrypting */
-                        rc = ecryptfs_decrypt_page(ecryptfs_page);
-                        if (rc) {
-                                printk(KERN_ERR "%s: Error decrypting "
-                                       "page; rc = [%d]\n",
-                                       __func__, rc);
-                                ClearPageUptodate(ecryptfs_page);
-                                page_cache_release(ecryptfs_page);
-                                goto out;
-                        }
-                }
                 ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0);
 
                 /*
@@ -349,14 +335,6 @@ int ecryptfs_read(char *data, loff_t offset, size_t size,
                                ecryptfs_page_idx, rc);
                         goto out;
                 }
-                rc = ecryptfs_decrypt_page(ecryptfs_page);
-                if (rc) {
-                        printk(KERN_ERR "%s: Error decrypting "
-                               "page; rc = [%d]\n", __func__, rc);
-                        ClearPageUptodate(ecryptfs_page);
-                        page_cache_release(ecryptfs_page);
-                        goto out;
-                }
                 ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0);
                 memcpy((data + data_offset),
                        ((char *)ecryptfs_page_virt + start_offset_in_page),