ocfs2: Add the 'inode64' mount option.

Now that ocfs2 limits inode numbers to 32bits, add a mount option to
disable the limit.  This parallels XFS.  64bit systems can handle the
larger inode numbers.

[ Added description of inode64 mount option in ocfs2.txt. --Mark ]

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

3 files changed, 21 insertions, 2 deletions

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 6d3c10ddf489..78ae4f87e6b0 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -189,6 +189,7 @@ enum ocfs2_mount_options
         OCFS2_MOUNT_DATA_WRITEBACK = 1 << 4, /* No data ordering */
         OCFS2_MOUNT_LOCALFLOCKS = 1 << 5, /* No cluster aware user file locks */
         OCFS2_MOUNT_NOUSERXATTR = 1 << 6, /* No user xattr */
+        OCFS2_MOUNT_INODE64 = 1 << 7,   /* Allow inode numbers > 2^32 */
 };
 
 #define OCFS2_OSB_SOFT_RO       0x0001
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 213bdca16fe4..d7a6f928c317 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -601,9 +601,10 @@ int ocfs2_reserve_new_inode(struct ocfs2_super *osb,
         /*
          * stat(2) can't handle i_ino > 32bits, so we tell the
          * lower levels not to allocate us a block group past that
-         * limit.
+         * limit.  The 'inode64' mount option avoids this behavior.
          */
-        (*ac)->ac_max_block = (u32)~0U;
+        if (!(osb->s_mount_opt & OCFS2_MOUNT_INODE64))
+                (*ac)->ac_max_block = (u32)~0U;
 
         /*
          * slot is set when we successfully steal inode from other nodes.
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index c85e525950a9..1a51c8c53bef 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -157,6 +157,7 @@ enum {
         Opt_stack,
         Opt_user_xattr,
         Opt_nouser_xattr,
+        Opt_inode64,
         Opt_err,
 };
 
@@ -178,6 +179,7 @@ static const match_table_t tokens = {
         {Opt_stack, "cluster_stack=%s"},
         {Opt_user_xattr, "user_xattr"},
         {Opt_nouser_xattr, "nouser_xattr"},
+        {Opt_inode64, "inode64"},
         {Opt_err, NULL}
 };
 
@@ -411,6 +413,15 @@ static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
                 goto out;
         }
 
+        /* Probably don't want this on remount; it might
+         * mess with other nodes */
+        if (!(osb->s_mount_opt & OCFS2_MOUNT_INODE64) &&
+            (parsed_options.mount_opt & OCFS2_MOUNT_INODE64)) {
+                ret = -EINVAL;
+                mlog(ML_ERROR, "Cannot enable inode64 on remount\n");
+                goto out;
+        }
+
         /* We're going to/from readonly mode. */
         if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY)) {
                 /* Lock here so the check of HARD_RO and the potential
@@ -930,6 +941,9 @@ static int ocfs2_parse_options(struct super_block *sb,
                                OCFS2_STACK_LABEL_LEN);
                         mopt->cluster_stack[OCFS2_STACK_LABEL_LEN] = '\0';
                         break;
+                case Opt_inode64:
+                        mopt->mount_opt |= OCFS2_MOUNT_INODE64;
+                        break;
                 default:
                         mlog(ML_ERROR,
                              "Unrecognized mount option \"%s\" "
@@ -994,6 +1008,9 @@ static int ocfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
                 seq_printf(s, ",cluster_stack=%.*s", OCFS2_STACK_LABEL_LEN,
                            osb->osb_cluster_stack);
 
+        if (opts & OCFS2_MOUNT_INODE64)
+                seq_printf(s, ",inode64");
+
         return 0;
 }