ocfs2: Add the USERSPACE_STACK incompat bit.
The filesystem gains the USERSPACE_STACK incomat bit and the
s_cluster_info field on the superblock. When a userspace stack is in
use, the name of the stack is stored on-disk for mount-time
verification.
The "cluster_stack" option is added to mount(2) processing. The mount
process needs to pass the matching stack name. If the passed name and
the on-disk name do not match, the mount is failed.
When using the classic o2cb stack, the incompat bit is *not* set and no
mount option is used other than the usual heartbeat=local. Thus, the
filesystem is compatible with older tools.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index c495023..52c4266 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -89,7 +89,8 @@
#define OCFS2_FEATURE_INCOMPAT_SUPP (OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT \
| OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC \
| OCFS2_FEATURE_INCOMPAT_INLINE_DATA \
- | OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP)
+ | OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP \
+ | OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK)
#define OCFS2_FEATURE_RO_COMPAT_SUPP OCFS2_FEATURE_RO_COMPAT_UNWRITTEN
/*
@@ -131,6 +132,17 @@
/*
+ * Support for alternate, userspace cluster stacks. If set, the superblock
+ * field s_cluster_info contains a tag for the alternate stack in use as
+ * well as the name of the cluster being joined.
+ * mount.ocfs2 must pass in a matching stack name.
+ *
+ * If not set, the classic stack will be used. This is compatbile with
+ * all older versions.
+ */
+#define OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK 0x0080
+
+/*
* backup superblock flag is used to indicate that this volume
* has backup superblocks.
*/
@@ -272,6 +284,10 @@
#define OCFS2_VOL_UUID_LEN 16
#define OCFS2_MAX_VOL_LABEL_LEN 64
+/* The alternate, userspace stack fields */
+#define OCFS2_STACK_LABEL_LEN 4
+#define OCFS2_CLUSTER_NAME_LEN 16
+
/* Journal limits (in bytes) */
#define OCFS2_MIN_JOURNAL_SIZE (4 * 1024 * 1024)
@@ -513,6 +529,13 @@
*/
};
+struct ocfs2_cluster_info {
+/*00*/ __u8 ci_stack[OCFS2_STACK_LABEL_LEN];
+ __le32 ci_reserved;
+/*08*/ __u8 ci_cluster[OCFS2_CLUSTER_NAME_LEN];
+/*18*/
+};
+
/*
* On disk superblock for OCFS2
* Note that it is contained inside an ocfs2_dinode, so all offsets
@@ -545,7 +568,20 @@
* group header */
/*50*/ __u8 s_label[OCFS2_MAX_VOL_LABEL_LEN]; /* Label for mounting, etc. */
/*90*/ __u8 s_uuid[OCFS2_VOL_UUID_LEN]; /* 128-bit uuid */
-/*A0*/
+/*A0*/ struct ocfs2_cluster_info s_cluster_info; /* Selected userspace
+ stack. Only valid
+ with INCOMPAT flag. */
+/*B8*/ __le64 s_reserved2[17]; /* Fill out superblock */
+/*140*/
+
+ /*
+ * NOTE: As stated above, all offsets are relative to
+ * ocfs2_dinode.id2, which is at 0xC0 in the inode.
+ * 0xC0 + 0x140 = 0x200 or 512 bytes. A superblock must fit within
+ * our smallest blocksize, which is 512 bytes. To ensure this,
+ * we reserve the space in s_reserved2. Anything past s_reserved2
+ * will not be available on the smallest blocksize.
+ */
};
/*