[PATCH] ocfs2: fix mount option parsing

For some mount option types, ocfs2_parse_options() will try to access
sb->s_fs_info to get at the ocfs2 private superblock. Unfortunately, that
hasn't been allocated yet and will cause a kernel crash.

Fix this by storing options in a struct which can then get pushed into the
ocfs2_super once it's been allocated later. If we need more options which
store to the ocfs2_super in the future, we can just fields to this struct.

Signed-off-by: Tiger Yang <tiger.yang@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 37 insertions, 32 deletions

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index f2fc9a795deb..c034b5129c1e 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -81,8 +81,15 @@ static struct dentry *ocfs2_debugfs_root = NULL;
 MODULE_AUTHOR("Oracle");
 MODULE_LICENSE("GPL");
 
+struct mount_options
+{
+        unsigned long   mount_opt;
+        unsigned int    atime_quantum;
+        signed short    slot;
+};
+
 static int ocfs2_parse_options(struct super_block *sb, char *options,
-                               unsigned long *mount_opt, s16 *slot,
+                               struct mount_options *mopt,
                                int is_remount);
 static void ocfs2_put_super(struct super_block *sb);
 static int ocfs2_mount_volume(struct super_block *sb);
@@ -367,24 +374,23 @@ static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
 {
         int incompat_features;
         int ret = 0;
-        unsigned long parsed_options;
-        s16 slot;
+        struct mount_options parsed_options;
         struct ocfs2_super *osb = OCFS2_SB(sb);
 
-        if (!ocfs2_parse_options(sb, data, &parsed_options, &slot, 1)) {
+        if (!ocfs2_parse_options(sb, data, &parsed_options, 1)) {
                 ret = -EINVAL;
                 goto out;
         }
 
         if ((osb->s_mount_opt & OCFS2_MOUNT_HB_LOCAL) !=
-            (parsed_options & OCFS2_MOUNT_HB_LOCAL)) {
+            (parsed_options.mount_opt & OCFS2_MOUNT_HB_LOCAL)) {
                 ret = -EINVAL;
                 mlog(ML_ERROR, "Cannot change heartbeat mode on remount\n");
                 goto out;
         }
 
         if ((osb->s_mount_opt & OCFS2_MOUNT_DATA_WRITEBACK) !=
-            (parsed_options & OCFS2_MOUNT_DATA_WRITEBACK)) {
+            (parsed_options.mount_opt & OCFS2_MOUNT_DATA_WRITEBACK)) {
                 ret = -EINVAL;
                 mlog(ML_ERROR, "Cannot change data mode on remount\n");
                 goto out;
@@ -435,7 +441,9 @@ unlock_osb:
 
                 /* Only save off the new mount options in case of a successful
                  * remount. */
-                osb->s_mount_opt = parsed_options;
+                osb->s_mount_opt = parsed_options.mount_opt;
+                osb->s_atime_quantum = parsed_options.atime_quantum;
+                osb->preferred_slot = parsed_options.slot;
         }
 out:
         return ret;
@@ -547,8 +555,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 {
         struct dentry *root;
         int status, sector_size;
-        unsigned long parsed_opt;
-        s16 slot;
+        struct mount_options parsed_options;
         struct inode *inode = NULL;
         struct ocfs2_super *osb = NULL;
         struct buffer_head *bh = NULL;
@@ -556,14 +563,14 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 
         mlog_entry("%p, %p, %i", sb, data, silent);
 
-        if (!ocfs2_parse_options(sb, data, &parsed_opt, &slot, 0)) {
+        if (!ocfs2_parse_options(sb, data, &parsed_options, 0)) {
                 status = -EINVAL;
                 goto read_super_error;
         }
 
         /* for now we only have one cluster/node, make sure we see it
          * in the heartbeat universe */
-        if (parsed_opt & OCFS2_MOUNT_HB_LOCAL) {
+        if (parsed_options.mount_opt & OCFS2_MOUNT_HB_LOCAL) {
                 if (!o2hb_check_local_node_heartbeating()) {
                         status = -EINVAL;
                         goto read_super_error;
@@ -585,8 +592,9 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
         }
         brelse(bh);
         bh = NULL;
-        osb->s_mount_opt = parsed_opt;
-        osb->preferred_slot = slot;
+        osb->s_mount_opt = parsed_options.mount_opt;
+        osb->s_atime_quantum = parsed_options.atime_quantum;
+        osb->preferred_slot = parsed_options.slot;
 
         sb->s_magic = OCFS2_SUPER_MAGIC;
 
@@ -728,8 +736,7 @@ static struct file_system_type ocfs2_fs_type = {
 
 static int ocfs2_parse_options(struct super_block *sb,
                                char *options,
-                               unsigned long *mount_opt,
-                               s16 *slot,
+                               struct mount_options *mopt,
                                int is_remount)
 {
         int status;
@@ -738,8 +745,9 @@ static int ocfs2_parse_options(struct super_block *sb,
         mlog_entry("remount: %d, options: \"%s\"\n", is_remount,
                    options ? options : "(none)");
 
-        *mount_opt = 0;
-        *slot = OCFS2_INVALID_SLOT;
+        mopt->mount_opt = 0;
+        mopt->atime_quantum = OCFS2_DEFAULT_ATIME_QUANTUM;
+        mopt->slot = OCFS2_INVALID_SLOT;
 
         if (!options) {
                 status = 1;
@@ -749,7 +757,6 @@ static int ocfs2_parse_options(struct super_block *sb,
         while ((p = strsep(&options, ",")) != NULL) {
                 int token, option;
                 substring_t args[MAX_OPT_ARGS];
-                struct ocfs2_super * osb = OCFS2_SB(sb);
 
                 if (!*p)
                         continue;
@@ -757,10 +764,10 @@ static int ocfs2_parse_options(struct super_block *sb,
                 token = match_token(p, tokens, args);
                 switch (token) {
                 case Opt_hb_local:
-                        *mount_opt |= OCFS2_MOUNT_HB_LOCAL;
+                        mopt->mount_opt |= OCFS2_MOUNT_HB_LOCAL;
                         break;
                 case Opt_hb_none:
-                        *mount_opt &= ~OCFS2_MOUNT_HB_LOCAL;
+                        mopt->mount_opt &= ~OCFS2_MOUNT_HB_LOCAL;
                         break;
                 case Opt_barrier:
                         if (match_int(&args[0], &option)) {
@@ -768,27 +775,27 @@ static int ocfs2_parse_options(struct super_block *sb,
                                 goto bail;
                         }
                         if (option)
-                                *mount_opt |= OCFS2_MOUNT_BARRIER;
+                                mopt->mount_opt |= OCFS2_MOUNT_BARRIER;
                         else
-                                *mount_opt &= ~OCFS2_MOUNT_BARRIER;
+                                mopt->mount_opt &= ~OCFS2_MOUNT_BARRIER;
                         break;
                 case Opt_intr:
-                        *mount_opt &= ~OCFS2_MOUNT_NOINTR;
+                        mopt->mount_opt &= ~OCFS2_MOUNT_NOINTR;
                         break;
                 case Opt_nointr:
-                        *mount_opt |= OCFS2_MOUNT_NOINTR;
+                        mopt->mount_opt |= OCFS2_MOUNT_NOINTR;
                         break;
                 case Opt_err_panic:
-                        *mount_opt |= OCFS2_MOUNT_ERRORS_PANIC;
+                        mopt->mount_opt |= OCFS2_MOUNT_ERRORS_PANIC;
                         break;
                 case Opt_err_ro:
-                        *mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
+                        mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
                         break;
                 case Opt_data_ordered:
-                        *mount_opt &= ~OCFS2_MOUNT_DATA_WRITEBACK;
+                        mopt->mount_opt &= ~OCFS2_MOUNT_DATA_WRITEBACK;
                         break;
                 case Opt_data_writeback:
-                        *mount_opt |= OCFS2_MOUNT_DATA_WRITEBACK;
+                        mopt->mount_opt |= OCFS2_MOUNT_DATA_WRITEBACK;
                         break;
                 case Opt_atime_quantum:
                         if (match_int(&args[0], &option)) {
@@ -796,9 +803,7 @@ static int ocfs2_parse_options(struct super_block *sb,
                                 goto bail;
                         }
                         if (option >= 0)
-                                osb->s_atime_quantum = option;
-                        else
-                                osb->s_atime_quantum = OCFS2_DEFAULT_ATIME_QUANTUM;
+                                mopt->atime_quantum = option;
                         break;
                 case Opt_slot:
                         option = 0;
@@ -807,7 +812,7 @@ static int ocfs2_parse_options(struct super_block *sb,
                                 goto bail;
                         }
                         if (option)
-                                *slot = (s16)option;
+                                mopt->slot = (s16)option;
                         break;
                 default:
                         mlog(ML_ERROR,