[PATCH 21/32] cachefiles: Round the cachefile size up to DIO block size

[David Howells]

Round the size of a cachefile up to DIO block size so that we can always
read back the last partial page of a file using direct I/O.

Signed-off-by: David Howells <dhowe...@redhat.com>
---

 fs/cachefiles/interface.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index de4fb41103a6..054d5cc794b5 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -184,6 +184,17 @@ static void cachefiles_update_object(struct fscache_object 
*_object)
                        cachefiles_remove_object_xattr(cache, object->dentry);
                        goto out;
                }
+
+               object_size = round_up(object_size, CACHEFILES_DIO_BLOCK_SIZE);
+               _debug("trunc %llx -> %llx", 
i_size_read(d_inode(object->dentry)), object_size);
+               if (i_size_read(d_inode(object->dentry)) < object_size) {
+                       ret = vfs_truncate(&path, object_size);
+                       if (ret < 0) {
+                               cachefiles_io_error_obj(object, 
"Trunc-to-dio-size failed");
+                               cachefiles_remove_object_xattr(cache, 
object->dentry);
+                               goto out;
+                       }
+               }
        }
 
        cachefiles_set_object_xattr(object, XATTR_REPLACE);
@@ -354,6 +365,7 @@ static int cachefiles_attr_changed(struct cachefiles_object 
*object)
        int ret;
 
        ni_size = object->fscache.cookie->object_size;
+       ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
 
        _enter("{OBJ%x},[%llu]",
               object->fscache.debug_id, (unsigned long long) ni_size);
@@ -422,6 +434,7 @@ static void cachefiles_invalidate_object(struct 
fscache_object *_object)
                             struct cachefiles_cache, cache);
 
        ni_size = object->fscache.cookie->object_size;
+       ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
 
        _enter("{OBJ%x},[%llu]",
               object->fscache.debug_id, (unsigned long long)ni_size);