alistair23-linux/fs/xfs/xfs_sysctl.h
Brian Foster 2e22717874 xfs: export log_recovery_delay to delay mount time log recovery
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>
2014-09-09 11:56:13 +10:00

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3.5 KiB
C

/*
* Copyright (c) 2001-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_SYSCTL_H__
#define __XFS_SYSCTL_H__
#include <linux/sysctl.h>
/*
* Tunable xfs parameters
*/
typedef struct xfs_sysctl_val {
int min;
int val;
int max;
} xfs_sysctl_val_t;
typedef struct xfs_param {
xfs_sysctl_val_t sgid_inherit; /* Inherit S_ISGID if process' GID is
* not a member of parent dir GID. */
xfs_sysctl_val_t symlink_mode; /* Link creat mode affected by umask */
xfs_sysctl_val_t panic_mask; /* bitmask to cause panic on errors. */
xfs_sysctl_val_t error_level; /* Degree of reporting for problems */
xfs_sysctl_val_t syncd_timer; /* Interval between xfssyncd wakeups */
xfs_sysctl_val_t stats_clear; /* Reset all XFS statistics to zero. */
xfs_sysctl_val_t inherit_sync; /* Inherit the "sync" inode flag. */
xfs_sysctl_val_t inherit_nodump;/* Inherit the "nodump" inode flag. */
xfs_sysctl_val_t inherit_noatim;/* Inherit the "noatime" inode flag. */
xfs_sysctl_val_t xfs_buf_timer; /* Interval between xfsbufd wakeups. */
xfs_sysctl_val_t xfs_buf_age; /* Metadata buffer age before flush. */
xfs_sysctl_val_t inherit_nosym; /* Inherit the "nosymlinks" flag. */
xfs_sysctl_val_t rotorstep; /* inode32 AG rotoring control knob */
xfs_sysctl_val_t inherit_nodfrg;/* Inherit the "nodefrag" inode flag. */
xfs_sysctl_val_t fstrm_timer; /* Filestream dir-AG assoc'n timeout. */
xfs_sysctl_val_t eofb_timer; /* Interval between eofb scan wakeups */
} xfs_param_t;
/*
* xfs_error_level:
*
* How much error reporting will be done when internal problems are
* encountered. These problems normally return an EFSCORRUPTED to their
* caller, with no other information reported.
*
* 0 No error reports
* 1 Report EFSCORRUPTED errors that will cause a filesystem shutdown
* 5 Report all EFSCORRUPTED errors (all of the above errors, plus any
* additional errors that are known to not cause shutdowns)
*
* xfs_panic_mask bit 0x8 turns the error reports into panics
*/
enum {
/* XFS_REFCACHE_SIZE = 1 */
/* XFS_REFCACHE_PURGE = 2 */
/* XFS_RESTRICT_CHOWN = 3 */
XFS_SGID_INHERIT = 4,
XFS_SYMLINK_MODE = 5,
XFS_PANIC_MASK = 6,
XFS_ERRLEVEL = 7,
XFS_SYNCD_TIMER = 8,
/* XFS_PROBE_DMAPI = 9 */
/* XFS_PROBE_IOOPS = 10 */
/* XFS_PROBE_QUOTA = 11 */
XFS_STATS_CLEAR = 12,
XFS_INHERIT_SYNC = 13,
XFS_INHERIT_NODUMP = 14,
XFS_INHERIT_NOATIME = 15,
XFS_BUF_TIMER = 16,
XFS_BUF_AGE = 17,
/* XFS_IO_BYPASS = 18 */
XFS_INHERIT_NOSYM = 19,
XFS_ROTORSTEP = 20,
XFS_INHERIT_NODFRG = 21,
XFS_FILESTREAM_TIMER = 22,
};
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);
#else
# define xfs_sysctl_register() (0)
# define xfs_sysctl_unregister() do { } while (0)
#endif /* CONFIG_SYSCTL */
#endif /* __XFS_SYSCTL_H__ */