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linux-next/fs/xfs/xfs_sysctl.h
Dave Chinner dae5cd8118 xfs: add mount delay debug option
Similar to log_recovery_delay, this delay occurs between the VFS
superblock being initialised and the xfs_mount being fully
initialised. It also poisons the per-ag radix tree node so that it
can be used for triggering shrinker races during mount
such as the following:

<run memory pressure workload in background>

$ cat dirty-mount.sh
#! /bin/bash

umount -f /dev/pmem0
mkfs.xfs -f /dev/pmem0
mount /dev/pmem0 /mnt/test
rm -f /mnt/test/foo
xfs_io -fxc "pwrite 0 4k" -c fsync -c "shutdown" /mnt/test/foo
umount /dev/pmem0

# let's crash it now!
echo 30 > /sys/fs/xfs/debug/mount_delay
mount /dev/pmem0 /mnt/test
echo 0 > /sys/fs/xfs/debug/mount_delay
umount /dev/pmem0
$ sudo ./dirty-mount.sh
.....
[   60.378118] CPU: 3 PID: 3577 Comm: fs_mark Tainted: G      D W        4.16.0-rc5-dgc #440
[   60.378120] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[   60.378124] RIP: 0010:radix_tree_next_chunk+0x76/0x320
[   60.378127] RSP: 0018:ffffc9000276f4f8 EFLAGS: 00010282
[   60.383670] RAX: a5a5a5a5a5a5a5a4 RBX: 0000000000000010 RCX: 000000000000001a
[   60.385277] RDX: 0000000000000000 RSI: ffffc9000276f540 RDI: 0000000000000000
[   60.386554] RBP: 0000000000000000 R08: 0000000000000000 R09: a5a5a5a5a5a5a5a5
[   60.388194] R10: 0000000000000006 R11: 0000000000000001 R12: ffffc9000276f598
[   60.389288] R13: 0000000000000040 R14: 0000000000000228 R15: ffff880816cd6458
[   60.390827] FS:  00007f5c124b9740(0000) GS:ffff88083fc00000(0000) knlGS:0000000000000000
[   60.392253] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   60.393423] CR2: 00007f5c11bba0b8 CR3: 000000035580e001 CR4: 00000000000606e0
[   60.394519] Call Trace:
[   60.395252]  radix_tree_gang_lookup_tag+0xc4/0x130
[   60.395948]  xfs_perag_get_tag+0x37/0xf0
[   60.396522]  xfs_reclaim_inodes_count+0x32/0x40
[   60.397178]  xfs_fs_nr_cached_objects+0x11/0x20
[   60.397837]  super_cache_count+0x35/0xc0
[   60.399159]  shrink_slab.part.66+0xb1/0x370
[   60.400194]  shrink_node+0x7e/0x1a0
[   60.401058]  try_to_free_pages+0x199/0x470
[   60.402081]  __alloc_pages_slowpath+0x3a1/0xd20
[   60.403729]  __alloc_pages_nodemask+0x1c3/0x200
[   60.404941]  cache_grow_begin+0x20b/0x2e0
[   60.406164]  fallback_alloc+0x160/0x200
[   60.407088]  kmem_cache_alloc+0x111/0x4e0
[   60.408038]  ? xfs_buf_rele+0x61/0x430
[   60.408925]  kmem_zone_alloc+0x61/0xe0
[   60.409965]  xfs_inode_alloc+0x24/0x1d0
.....


Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-15 17:57:05 -07:00

112 lines
3.7 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_sysctl_val_t cowb_timer; /* Interval between cowb 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) */
int mount_delay; /* mount setup delay (secs) */
bool bug_on_assert; /* BUG() the kernel on assert failure */
};
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__ */