ecryptfs: modify write path to encrypt page in writepage

Change the write path to encrypt the data only when the page is written to
disk in ecryptfs_writepage. Previously, ecryptfs encrypts the page in
ecryptfs_write_end which means that if there are multiple write requests to
the same page, ecryptfs ends up re-encrypting that page over and over again.
This patch minimizes the number of encryptions needed.

Signed-off-by: Thieu Le <thieule@chromium.org>
[tyhicks: Changed NULL .drop_inode sop pointer to generic_drop_inode]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index db184ef15d3d..85d430963116 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -44,15 +44,11 @@ int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
         ssize_t rc;
 
         inode_info = ecryptfs_inode_to_private(ecryptfs_inode);
-        mutex_lock(&inode_info->lower_file_mutex);
         BUG_ON(!inode_info->lower_file);
-        inode_info->lower_file->f_pos = offset;
         fs_save = get_fs();
         set_fs(get_ds());
-        rc = vfs_write(inode_info->lower_file, data, size,
-                       &inode_info->lower_file->f_pos);
+        rc = vfs_write(inode_info->lower_file, data, size, &offset);
         set_fs(fs_save);
-        mutex_unlock(&inode_info->lower_file_mutex);
         mark_inode_dirty_sync(ecryptfs_inode);
         return rc;
 }
@@ -234,15 +230,11 @@ int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
         mm_segment_t fs_save;
         ssize_t rc;
 
-        mutex_lock(&inode_info->lower_file_mutex);
         BUG_ON(!inode_info->lower_file);
-        inode_info->lower_file->f_pos = offset;
         fs_save = get_fs();
         set_fs(get_ds());
-        rc = vfs_read(inode_info->lower_file, data, size,
-                      &inode_info->lower_file->f_pos);
+        rc = vfs_read(inode_info->lower_file, data, size, &offset);
         set_fs(fs_save);
-        mutex_unlock(&inode_info->lower_file_mutex);
         return rc;
 }