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alistair23-linux/fs/xfs/xfs_globals.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
/*
* Tunable XFS parameters. xfs_params is required even when CONFIG_SYSCTL=n,
* other XFS code uses these values. Times are measured in centisecs (i.e.
* 100ths of a second) with the exception of eofb_timer and cowb_timer, which
* are measured in seconds.
*/
xfs_param_t xfs_params = {
/* MIN DFLT MAX */
.sgid_inherit = { 0, 0, 1 },
.symlink_mode = { 0, 0, 1 },
.panic_mask = { 0, 0, 256 },
.error_level = { 0, 3, 11 },
.syncd_timer = { 1*100, 30*100, 7200*100},
.stats_clear = { 0, 0, 1 },
.inherit_sync = { 0, 1, 1 },
.inherit_nodump = { 0, 1, 1 },
.inherit_noatim = { 0, 1, 1 },
.xfs_buf_timer = { 100/2, 1*100, 30*100 },
.xfs_buf_age = { 1*100, 15*100, 7200*100},
.inherit_nosym = { 0, 0, 1 },
.rotorstep = { 1, 1, 255 },
.inherit_nodfrg = { 0, 1, 1 },
.fstrm_timer = { 1, 30*100, 3600*100},
.eofb_timer = { 1, 300, 3600*24},
.cowb_timer = { 1, 1800, 3600*24},
};
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>
2014-09-08 19:56:13 -06:00
struct xfs_globals xfs_globals = {
.log_recovery_delay = 0, /* no delay by default */
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>
2018-05-10 22:50:23 -06:00
.mount_delay = 0, /* no delay by default */
#ifdef XFS_ASSERT_FATAL
.bug_on_assert = true, /* assert failures BUG() */
#else
.bug_on_assert = false, /* assert failures WARN() */
#endif
#ifdef DEBUG
.pwork_threads = -1, /* automatic thread detection */
#endif
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>
2014-09-08 19:56:13 -06:00
};