[PATCH 30/67] 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 <dhowells@xxxxxxxxxx>
---

 fs/cachefiles/bind.c      |    3 ++-
 fs/cachefiles/interface.c |    2 ++
 fs/cachefiles/internal.h  |    2 ++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c
index af7386ad14af..4ea8c93e14d8 100644
--- a/fs/cachefiles/bind.c
+++ b/fs/cachefiles/bind.c
@@ -126,7 +126,8 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache)
 	    !d_backing_inode(root)->i_op->mkdir ||
 	    !(d_backing_inode(root)->i_opflags & IOP_XATTR) ||
 	    !root->d_sb->s_op->statfs ||
-	    !root->d_sb->s_op->sync_fs)
+	    !root->d_sb->s_op->sync_fs ||
+	    root->d_sb->s_blocksize > PAGE_SIZE)
 		goto error_unsupported;
 
 	ret = -EROFS;
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 8f98e5c27d66..3e678ab14c85 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -268,6 +268,7 @@ static int cachefiles_attr_changed(struct cachefiles_object *object)
 	int ret;
 
 	ni_size = object->cookie->object_size;
+	ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
 
 	_enter("{OBJ%x},[%llu]",
 	       object->debug_id, (unsigned long long) ni_size);
@@ -346,6 +347,7 @@ static void cachefiles_invalidate_object(struct cachefiles_object *object)
 				       cachefiles_trunc_invalidate);
 		ret = vfs_truncate(&file->f_path, 0);
 		if (ret == 0) {
+			ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
 			trace_cachefiles_trunc(object, file_inode(file),
 					       0, ni_size,
 					       cachefiles_trunc_set_size);
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 4705f968e661..ff00c5249f4f 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -19,6 +19,8 @@
 #include <linux/workqueue.h>
 #include <linux/security.h>
 
+#define CACHEFILES_DIO_BLOCK_SIZE 4096
+
 struct cachefiles_cache;
 struct cachefiles_object;