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.h b/fs/ocfs2/ocfs2.h
index af929eca5412ca26ba479b68091e7d1583aafecb..9ff5811345a995bf82279aa42fe6fa8e335524cc 100644 (file)
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -248,6 +248,7 @@ struct ocfs2_super
        struct ocfs2_alloc_stats alloc_stats;
        char dev_str[20];               /* "major,minor" of the device */
 
+       char osb_cluster_stack[OCFS2_STACK_LABEL_LEN + 1];
        struct ocfs2_cluster_connection *cconn;
        struct ocfs2_lock_res osb_super_lockres;
        struct ocfs2_lock_res osb_rename_lockres;
@@ -368,6 +369,12 @@ static inline int ocfs2_is_soft_readonly(struct ocfs2_super *osb)
        return ret;
 }
 
+static inline int ocfs2_userspace_stack(struct ocfs2_super *osb)
+{
+       return (osb->s_feature_incompat &
+               OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK);
+}
+
 static inline int ocfs2_mount_local(struct ocfs2_super *osb)
 {
        return (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT);

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index c49502329ab0b19276743675f61abea4086da25d..52c426665154312cb0d7c812bed5f0b928a8e62d 100644 (file)
--- 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
 
 /*
@@ -130,6 +131,17 @@
 #define OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP 0x100
 
 
+/*
+ * 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 @@ struct ocfs2_new_group_input {
 #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_slot_map_extended {
  */
 };
 
+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 @@ struct ocfs2_super_block {
                                         * 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.
+        */
 };
 
 /*

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index e27a0d47ea2b84d4992b46abe3000b404e9517f2..96ebe36d5d77f0e292839e1fe505ebe480204e0b 100644 (file)
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -87,6 +87,7 @@ struct mount_options
        unsigned int    atime_quantum;
        signed short    slot;
        unsigned int    localalloc_opt;
+       char            cluster_stack[OCFS2_STACK_LABEL_LEN + 1];
 };
 
 static int ocfs2_parse_options(struct super_block *sb, char *options,
@@ -152,6 +153,7 @@ enum {
        Opt_commit,
        Opt_localalloc,
        Opt_localflocks,
+       Opt_stack,
        Opt_err,
 };
 
@@ -170,6 +172,7 @@ static match_table_t tokens = {
        {Opt_commit, "commit=%u"},
        {Opt_localalloc, "localalloc=%d"},
        {Opt_localflocks, "localflocks"},
+       {Opt_stack, "cluster_stack=%s"},
        {Opt_err, NULL}
 };
 
@@ -549,8 +552,17 @@ static int ocfs2_verify_heartbeat(struct ocfs2_super *osb)
                }
        }
 
+       if (ocfs2_userspace_stack(osb)) {
+               if (osb->s_mount_opt & OCFS2_MOUNT_HB_LOCAL) {
+                       mlog(ML_ERROR, "Userspace stack expected, but "
+                            "o2cb heartbeat arguments passed to mount\n");
+                       return -EINVAL;
+               }
+       }
+
        if (!(osb->s_mount_opt & OCFS2_MOUNT_HB_LOCAL)) {
-               if (!ocfs2_mount_local(osb) && !ocfs2_is_hard_readonly(osb)) {
+               if (!ocfs2_mount_local(osb) && !ocfs2_is_hard_readonly(osb) &&
+                   !ocfs2_userspace_stack(osb)) {
                        mlog(ML_ERROR, "Heartbeat has to be started to mount "
                             "a read-write clustered device.\n");
                        return -EINVAL;
@@ -560,6 +572,35 @@ static int ocfs2_verify_heartbeat(struct ocfs2_super *osb)
        return 0;
 }
 
+/*
+ * If we're using a userspace stack, mount should have passed
+ * a name that matches the disk.  If not, mount should not
+ * have passed a stack.
+ */
+static int ocfs2_verify_userspace_stack(struct ocfs2_super *osb,
+                                       struct mount_options *mopt)
+{
+       if (!ocfs2_userspace_stack(osb) && mopt->cluster_stack[0]) {
+               mlog(ML_ERROR,
+                    "cluster stack passed to mount, but this filesystem "
+                    "does not support it\n");
+               return -EINVAL;
+       }
+
+       if (ocfs2_userspace_stack(osb) &&
+           strncmp(osb->osb_cluster_stack, mopt->cluster_stack,
+                   OCFS2_STACK_LABEL_LEN)) {
+               mlog(ML_ERROR,
+                    "cluster stack passed to mount (\"%s\") does not "
+                    "match the filesystem (\"%s\")\n",
+                    mopt->cluster_stack,
+                    osb->osb_cluster_stack);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
 static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 {
        struct dentry *root;
@@ -598,6 +639,10 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
        osb->osb_commit_interval = parsed_options.commit_interval;
        osb->local_alloc_size = parsed_options.localalloc_opt;
 
+       status = ocfs2_verify_userspace_stack(osb, &parsed_options);
+       if (status)
+               goto read_super_error;
+
        sb->s_magic = OCFS2_SUPER_MAGIC;
 
        /* Hard readonly mode only if: bdev_read_only, MS_RDONLY,
@@ -752,6 +797,7 @@ static int ocfs2_parse_options(struct super_block *sb,
        mopt->atime_quantum = OCFS2_DEFAULT_ATIME_QUANTUM;
        mopt->slot = OCFS2_INVALID_SLOT;
        mopt->localalloc_opt = OCFS2_DEFAULT_LOCAL_ALLOC_SIZE;
+       mopt->cluster_stack[0] = '\0';
 
        if (!options) {
                status = 1;
@@ -853,6 +899,25 @@ static int ocfs2_parse_options(struct super_block *sb,
                        if (!is_remount)
                                mopt->mount_opt |= OCFS2_MOUNT_LOCALFLOCKS;
                        break;
+               case Opt_stack:
+                       /* Check both that the option we were passed
+                        * is of the right length and that it is a proper
+                        * string of the right length.
+                        */
+                       if (((args[0].to - args[0].from) !=
+                            OCFS2_STACK_LABEL_LEN) ||
+                           (strnlen(args[0].from,
+                                    OCFS2_STACK_LABEL_LEN) !=
+                            OCFS2_STACK_LABEL_LEN)) {
+                               mlog(ML_ERROR,
+                                    "Invalid cluster_stack option\n");
+                               status = 0;
+                               goto bail;
+                       }
+                       memcpy(mopt->cluster_stack, args[0].from,
+                              OCFS2_STACK_LABEL_LEN);
+                       mopt->cluster_stack[OCFS2_STACK_LABEL_LEN] = '\0';
+                       break;
                default:
                        mlog(ML_ERROR,
                             "Unrecognized mount option \"%s\" "
@@ -911,6 +976,10 @@ static int ocfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
        if (opts & OCFS2_MOUNT_LOCALFLOCKS)
                seq_printf(s, ",localflocks,");
 
+       if (osb->osb_cluster_stack[0])
+               seq_printf(s, ",cluster_stack=%.*s", OCFS2_STACK_LABEL_LEN,
+                          osb->osb_cluster_stack);
+
        return 0;
 }
 
@@ -1403,6 +1472,25 @@ static int ocfs2_initialize_super(struct super_block *sb,
                goto bail;
        }
 
+       if (ocfs2_userspace_stack(osb)) {
+               memcpy(osb->osb_cluster_stack,
+                      OCFS2_RAW_SB(di)->s_cluster_info.ci_stack,
+                      OCFS2_STACK_LABEL_LEN);
+               osb->osb_cluster_stack[OCFS2_STACK_LABEL_LEN] = '\0';
+               if (strlen(osb->osb_cluster_stack) != OCFS2_STACK_LABEL_LEN) {
+                       mlog(ML_ERROR,
+                            "couldn't mount because of an invalid "
+                            "cluster stack label (%s) \n",
+                            osb->osb_cluster_stack);
+                       status = -EINVAL;
+                       goto bail;
+               }
+       } else {
+               /* The empty string is identical with classic tools that
+                * don't know about s_cluster_info. */
+               osb->osb_cluster_stack[0] = '\0';
+       }
+
        get_random_bytes(&osb->s_next_generation, sizeof(u32));
 
        /* FIXME