4 files changed, 52 insertions, 0 deletions

diff --git a/fs/xfs/xfs_globals.c b/fs/xfs/xfs_globals.c
index 5399ef222dd7..4d41b241298f 100644
--- a/fs/xfs/xfs_globals.c
+++ b/fs/xfs/xfs_globals.c
@@ -43,3 +43,7 @@ xfs_param_t xfs_params = {
         .fstrm_timer    = {     1,              30*100,         3600*100},
         .eofb_timer     = {     1,              300,            3600*24},
 };
+
+struct xfs_globals xfs_globals = {
+        .log_recovery_delay     =       0,      /* no delay by default */
+};
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 1fd5787add99..176c4b3609ab 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -4509,6 +4509,18 @@ xlog_recover(
                         return -EINVAL;
                 }
 
+                /*
+                 * Delay log recovery if the debug hook is set. This is debug
+                 * instrumention to coordinate simulation of I/O failures with
+                 * log recovery.
+                 */
+                if (xfs_globals.log_recovery_delay) {
+                        xfs_notice(log->l_mp,
+                                "Delaying log recovery for %d seconds.",
+                                xfs_globals.log_recovery_delay);
+                        msleep(xfs_globals.log_recovery_delay * 1000);
+                }
+
                 xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
                                 log->l_mp->m_logname ? log->l_mp->m_logname
                                                      : "internal");
diff --git a/fs/xfs/xfs_sysctl.h b/fs/xfs/xfs_sysctl.h
index bd8e157c20ef..ffef45375754 100644
--- a/fs/xfs/xfs_sysctl.h
+++ b/fs/xfs/xfs_sysctl.h
@@ -92,6 +92,11 @@ enum {
 
 extern xfs_param_t      xfs_params;
 
+struct xfs_globals {
+        int     log_recovery_delay;     /* log recovery delay (secs) */
+};
+extern struct xfs_globals       xfs_globals;
+
 #ifdef CONFIG_SYSCTL
 extern int xfs_sysctl_register(void);
 extern void xfs_sysctl_unregister(void);
diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
index 32ddf0c8c50e..aa03670851d8 100644
--- a/fs/xfs/xfs_sysfs.c
+++ b/fs/xfs/xfs_sysfs.c
@@ -54,7 +54,38 @@ struct kobj_type xfs_mp_ktype = {
 #ifdef DEBUG
 /* debug */
 
+STATIC ssize_t
+log_recovery_delay_store(
+        const char      *buf,
+        size_t          count,
+        void            *data)
+{
+        int             ret;
+        int             val;
+
+        ret = kstrtoint(buf, 0, &val);
+        if (ret)
+                return ret;
+
+        if (val < 0 || val > 60)
+                return -EINVAL;
+
+        xfs_globals.log_recovery_delay = val;
+
+        return count;
+}
+
+STATIC ssize_t
+log_recovery_delay_show(
+        char    *buf,
+        void    *data)
+{
+        return snprintf(buf, PAGE_SIZE, "%d\n", xfs_globals.log_recovery_delay);
+}
+XFS_SYSFS_ATTR_RW(log_recovery_delay);
+
 static struct attribute *xfs_dbg_attrs[] = {
+        ATTR_LIST(log_recovery_delay),
         NULL,
 };