xfs: export log_recovery_delay to delay mount time log recovery (2e227178) · Commits · 戴 / test

XFS log recovery has been discovered to have race conditions with buffers when I/O errors occur. External tools are available to simulate I/O errors to XFS, but this alone is not sufficient for testing log recovery. XFS unconditionally resets the inactive region of the log prior to log recovery to avoid confusion over processing any partially written log records that might have been written before an unclean shutdown. Therefore, unconditional write I/O failures at mount time are caught by the reset sequence rather than log recovery and hinder the ability to test the latter. The device-mapper dm-flakey module uses an up/down timer to define a cycle for when to fail I/Os. Create a pre log recovery delay tunable that can be used to coordinate XFS log recovery with I/O errors simulated by dm-flakey. This facilitates coordination in userspace that allows the reset of stale log blocks to succeed and writes due to log recovery to fail. For example, define a dm-flakey instance with an uptime long enough to allow log reset to succeed and a log recovery delay long enough to allow the dm-flakey uptime to expire. The 'log_recovery_delay' sysfs tunable is exported under /sys/fs/xfs/debug and is only enabled for kernels compiled in XFS debug mode. The value is exported in units of seconds and allows for a delay of up to 60 seconds. Note that this is for XFS debug and test instrumentation purposes only and should not be used by applications. No delay is enabled by default. Signed-off-by:

Brian Foster <bfoster@redhat.com> Reviewed-by:

Dave Chinner <dchinner@redhat.com> Signed-off-by:

Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_globals.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -43,3 +43,7 @@ xfs_param_t xfs_params = {
		.fstrm_timer = { 1, 30100, 3600100},
		.eofb_timer = { 1, 300, 3600*24},
		};

		struct xfs_globals xfs_globals = {
		.log_recovery_delay = 0, /* no delay by default */
		};

fs/xfs/xfs_log_recover.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -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");

fs/xfs/xfs_sysctl.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -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);

fs/xfs/xfs_sysfs.c

+31 −0

Original line number	Diff line number	Diff line
		@@ -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,
		};

Admin message