ceph: consider inode's last read/write when calculating wanted caps

Add i_last_rd and i_last_wr to ceph_inode_info. These fields are
used to track the last time the client acquired read/write caps for
the inode.

If there is no read/write on an inode for 'caps_wanted_delay_max'
seconds, __ceph_caps_file_wanted() does not request caps for read/write
even there are open files.

Call __ceph_touch_fmode() for dir operations. __ceph_caps_file_wanted()
calculates dir's wanted caps according to last dir read/modification. If
there is recent dir read, dir inode wants CEPH_CAP_ANY_SHARED caps. If
there is recent dir modification, also wants CEPH_CAP_FILE_EXCL.

Readdir is a special case. Dir inode wants CEPH_CAP_FILE_EXCL after
readdir, as with that, modifications do not need to release
CEPH_CAP_FILE_SHARED or invalidate all dentry leases issued by readdir.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index a6c4841..6239cff 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -213,7 +213,7 @@ static int ceph_init_file_info(struct inode *inode, struct file *file,
 		struct ceph_dir_file_info *dfi =
 			kmem_cache_zalloc(ceph_dir_file_cachep, GFP_KERNEL);
 		if (!dfi) {
-			ceph_put_fmode(ci, fmode); /* clean up */
+			ceph_put_fmode(ci, fmode, 1); /* clean up */
 			return -ENOMEM;
 		}
 
@@ -224,7 +224,7 @@ static int ceph_init_file_info(struct inode *inode, struct file *file,
 	} else {
 		fi = kmem_cache_zalloc(ceph_file_cachep, GFP_KERNEL);
 		if (!fi) {
-			ceph_put_fmode(ci, fmode); /* clean up */
+			ceph_put_fmode(ci, fmode, 1); /* clean up */
 			return -ENOMEM;
 		}
 
@@ -263,7 +263,7 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 	case S_IFLNK:
 		dout("init_file %p %p 0%o (symlink)\n", inode, file,
 		     inode->i_mode);
-		ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+		ceph_put_fmode(ceph_inode(inode), fmode, 1); /* clean up */
 		break;
 
 	default:
@@ -273,7 +273,7 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 		 * we need to drop the open ref now, since we don't
 		 * have .release set to ceph_release.
 		 */
-		ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+		ceph_put_fmode(ceph_inode(inode), fmode, 1); /* clean up */
 		BUG_ON(inode->i_fop->release == ceph_release);
 
 		/* call the proper open fop */
@@ -285,14 +285,15 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 /*
  * try renew caps after session gets killed.
  */
-int ceph_renew_caps(struct inode *inode)
+int ceph_renew_caps(struct inode *inode, int fmode)
 {
-	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_mds_request *req;
 	int err, flags, wanted;
 
 	spin_lock(&ci->i_ceph_lock);
+	__ceph_touch_fmode(ci, mdsc, fmode);
 	wanted = __ceph_caps_file_wanted(ci);
 	if (__ceph_is_any_real_caps(ci) &&
 	    (!(wanted & CEPH_CAP_ANY_WR) || ci->i_auth_cap)) {
@@ -405,6 +406,7 @@ int ceph_open(struct inode *inode, struct file *file)
 	} else if (ceph_snap(inode) != CEPH_NOSNAP &&
 		   (ci->i_snap_caps & wanted) == wanted) {
 		__ceph_get_fmode(ci, fmode);
+		__ceph_touch_fmode(ci, mdsc, fmode);
 		spin_unlock(&ci->i_ceph_lock);
 		return ceph_init_file(inode, file, fmode);
 	}
@@ -781,7 +783,7 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 	}
 out_req:
 	if (!req->r_err && req->r_target_inode)
-		ceph_put_fmode(ceph_inode(req->r_target_inode), req->r_fmode);
+		ceph_put_fmode(ceph_inode(req->r_target_inode), req->r_fmode, 1);
 	ceph_mdsc_put_request(req);
 out_ctx:
 	ceph_release_acl_sec_ctx(&as_ctx);
@@ -798,7 +800,7 @@ int ceph_release(struct inode *inode, struct file *file)
 		dout("release inode %p dir file %p\n", inode, file);
 		WARN_ON(!list_empty(&dfi->file_info.rw_contexts));
 
-		ceph_put_fmode(ci, dfi->file_info.fmode);
+		ceph_put_fmode(ci, dfi->file_info.fmode, 1);
 
 		if (dfi->last_readdir)
 			ceph_mdsc_put_request(dfi->last_readdir);
@@ -810,7 +812,8 @@ int ceph_release(struct inode *inode, struct file *file)
 		dout("release inode %p regular file %p\n", inode, file);
 		WARN_ON(!list_empty(&fi->rw_contexts));
 
-		ceph_put_fmode(ci, fi->fmode);
+		ceph_put_fmode(ci, fi->fmode, 1);
+
 		kmem_cache_free(ceph_file_cachep, fi);
 	}