xfs: Introduce a new ioctl(2) to set AG state

Introduce a new ioctl(2) for setting a.g. state.

- Add a new structure xfs_ioc_agstate.
- Add a macro to indicate an a.g. is offline.
- Add XFS_IOC_SET_AGSTATE for ioctl(2).
- Teach xfs_alloc_log_agf() aware of agf_state.

Signed-off-by Jie Liu <[email protected]>

---
 fs/xfs/xfs_ag.h    |   17 ++++++++++++
 fs/xfs/xfs_alloc.c |    1 +
 fs/xfs/xfs_fs.h    |    1 +
 fs/xfs/xfs_fsops.c |   73 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 fs/xfs/xfs_ioctl.c |   13 +++++++++
 fs/xfs/xfs_trans.h |    2 +-
 6 files changed, 104 insertions(+), 3 deletions(-)

fs/xfs/xfs_ag.h +17 -0

index fd578e6..e2588d9 100644
@@ -235,6 +235,23 @@ typedef struct xfs_perag {
 } xfs_perag_t;
 
 /*
+ * Structure for ioctl per a.g. state get/set.
+ */
+typedef struct xfs_ioc_agstate {
+	xfs_agnumber_t	agno;
+	__uint32_t	state;
+} xfs_ioc_agstate_t;
+
+/*
+ * Skip an AG with below state for inodes/blocks allocation.
+ */
+#define XFS_AG_STATE_ALLOC_DENY		(1 << 0)
+#define XFS_AG_ALL_STATE		(XFS_AG_STATE_ALLOC_DENY)
+
+extern int xfs_set_agstate(struct xfs_mount *mp,
+			   struct xfs_ioc_agstate *agstate);
+
+/*
  * tags for inode radix tree
  */
 #define XFS_ICI_NO_TAG		(-1)	/* special flag for an untagged lookup

fs/xfs/xfs_alloc.c +1 -0

index 4f33c32..bd9cc41 100644
@@ -2005,6 +2005,7 @@ xfs_alloc_log_agf(
 		offsetof(xfs_agf_t, agf_freeblks),
 		offsetof(xfs_agf_t, agf_longest),
 		offsetof(xfs_agf_t, agf_btreeblks),
+		offsetof(xfs_agf_t, agf_state),
 		sizeof(xfs_agf_t)
 	};
 

fs/xfs/xfs_fs.h +1 -0

index c13fed8..991c09e 100644
@@ -486,6 +486,7 @@ typedef struct xfs_handle {
 #define XFS_IOC_ATTRMULTI_BY_HANDLE  _IOW ('X', 123, struct xfs_fsop_attrmulti_handlereq)
 #define XFS_IOC_FSGEOMETRY	     _IOR ('X', 124, struct xfs_fsop_geom)
 #define XFS_IOC_GOINGDOWN	     _IOR ('X', 125, __uint32_t)
+#define XFS_IOC_SET_AGSTATE	     _IOW('X', 126, struct xfs_ioc_agstate)
 /*	XFS_IOC_GETFSUUID ---------- deprecated 140	 */
 
 

fs/xfs/xfs_fsops.c +33 -0

index c25b094..3742511 100644
@@ -112,10 +112,79 @@ xfs_fs_geometry(
 	return 0;
 }
 
+/*
+ * Setting a.g. persistent state as well as perag incore state.
+ */
+static void
+xfs_set_agstate_private(
+	xfs_trans_t	*tp,	/* transaction pointer */
+	xfs_buf_t	*agbp,	/* buffer for a.g. freelist header */
+	xfs_perag_t	*pag,	/* incore perag structure */
+	__uint32_t	state)  /* a.g. state to be set */
+{
+	xfs_agf_t	*agf;	/* a.g. free space */
+
+	agf = XFS_BUF_TO_AGF(agbp);
+	agf->agf_state |= cpu_to_be32(state);
+	pag->pag_state |= state;
+
+	xfs_alloc_log_agf(tp, agbp, XFS_AGF_STATE);
+}
+
+/*
+ * Setting the state of the given AG.
+ *
+ * For now, we can set a given AG to be offline or online, and
+ * allocaters will skip an AG being offline to allocate inodes
+ * or free space.
+ */
+int
+xfs_set_agstate(
+	xfs_mount_t		*mp,
+	xfs_ioc_agstate_t	*agstate)
+{
+	xfs_agnumber_t		agno;
+	xfs_perag_t		*pag;

fs/xfs/xfs_fsops.c +28 -2

+
+	tp = xfs_trans_alloc(mp, XFS_TRANS_SET_AGSTATE);
+	error = xfs_trans_reserve(tp, 0, XFS_SETAGSTATE_LOG_RES(mp), 0, 0,
+				  XFS_DEFAULT_LOG_COUNT);
+	if (error) {
+		xfs_trans_cancel(tp, 0);
+		return error;
+	}
+
+	error = xfs_alloc_read_agf(mp, tp, agno, 0, &bp);
+	if (error)
+		goto error0;
+
+	pag = xfs_perag_get(mp, agno);
+	xfs_set_agstate_private(tp, bp, pag, agstate->state);
+	xfs_perag_put(pag);
+
+	xfs_trans_set_sync(tp);
+	xfs_trans_commit(tp, 0);
+	return error;
+
+error0:
+	xfs_trans_cancel(tp, XFS_TRANS_ABORT);
+	return error;
+}
+
 static int
 xfs_growfs_data_private(
-	xfs_mount_t		*mp,		/* mount point for filesystem */
-	xfs_growfs_data_t	*in)		/* growfs data input struct */
+	xfs_mount_t		*mp,	/* mount point for filesystem */
+	xfs_growfs_data_t	*in)	/* growfs data input struct */
 {
 	xfs_agf_t		*agf;
 	xfs_agi_t		*agi;

fs/xfs/xfs_ioctl.c +13 -0

index 8305f2a..efe39ef 100644
@@ -1602,6 +1602,19 @@ xfs_file_ioctl(
 		error = xfs_errortag_clearall(mp, 1);
 		return -error;
 
+	case XFS_IOC_SET_AGSTATE: {
+		xfs_ioc_agstate_t in;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&in, arg, sizeof(in)))
+			return -XFS_ERROR(EFAULT);
+
+		error = xfs_set_agstate(mp, &in);
+		return -error;
+	}
+
 	default:
 		return -ENOTTY;
 	}

fs/xfs/xfs_trans.h +0 -0

index a4f4092..14f897d 100644