ceph: add truncate size handling support for fscrypt

This will transfer the encrypted last block contents to the MDS
along with the truncate request only when the new size is smaller
and not aligned to the fscrypt BLOCK size. When the last block is
located in the file hole, the truncate request will only contain
the header.

The MDS could fail to do the truncate if there has another client
or process has already updated the RADOS object which contains
the last block, and will return -EAGAIN, then the kclient needs
to retry it. The RMW will take around 50ms, and will let it retry
20 times for now.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index d60342cc6f33..b5e54c8f010b 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -424,6 +424,11 @@ struct ceph_inode_info {
 	u32 i_truncate_seq;        /* last truncate to smaller size */
 	u64 i_truncate_size;       /*  and the size we last truncated down to */
 	int i_truncate_pending;    /*  still need to call vmtruncate */
+	/*
+	 * For none fscrypt case it equals to i_truncate_size or it will
+	 * equals to fscrypt_file_size
+	 */
+	u64 i_truncate_pagecache_size;
 
 	u64 i_max_size;            /* max file size authorized by mds */
 	u64 i_reported_size; /* (max_)size reported to or requested of mds */
@@ -1265,6 +1270,8 @@ extern int ceph_encode_dentry_release(void **p, struct dentry *dn,
 				      struct inode *dir,
 				      int mds, int drop, int unless);
 
+extern int __ceph_get_caps(struct inode *inode, struct ceph_file_info *fi,
+			   int need, int want, loff_t endoff, int *got);
 extern int ceph_get_caps(struct file *filp, int need, int want,
 			 loff_t endoff, int *got);
 extern int ceph_try_get_caps(struct inode *inode,