afs: Fix getattr to report server i_size on dirs, not local size

[ Upstream commit 45f66fa03ba9943cca5af88d691399332b8bde08 ]

Fix afs_getattr() to report the server's idea of the file size of a
directory rather than the local size.  The local size may differ as we edit
the local copy to avoid having to redownload it and we may end up with a
differently structured blob of a different size.

However, if the directory is discarded from the pagecache we then download
it again and the user may see the directory file size apparently change.

Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 52d040f..5921dd3 100644 (file)
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -450,7 +450,7 @@ static void afs_get_inode_cache(struct afs_vnode *vnode)
                                    0 : FSCACHE_ADV_SINGLE_CHUNK,
                                    &key, sizeof(key),
                                    &aux, sizeof(aux),
-                                   vnode->status.size));
+                                   i_size_read(&vnode->netfs.inode)));
 #endif
 }
 
@@ -766,6 +766,13 @@ int afs_getattr(struct user_namespace *mnt_userns, const struct path *path,
                if (test_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags) &&
                    stat->nlink > 0)
                        stat->nlink -= 1;
+
+               /* Lie about the size of directories.  We maintain a locally
+                * edited copy and may make different allocation decisions on
+                * it, but we need to give userspace the server's size.
+                */
+               if (S_ISDIR(inode->i_mode))
+                       stat->size = vnode->netfs.remote_i_size;
        } while (need_seqretry(&vnode->cb_lock, seq));
 
        done_seqretry(&vnode->cb_lock, seq);