linux/Documentation
Eric Sandeen c2d7543851 filesystem freeze: allow SysRq emergency thaw to thaw frozen filesystems
Now that the filesystem freeze operation has been elevated to the VFS, and
is just an ioctl away, some sort of safety net for unintentionally frozen
root filesystems may be in order.

The timeout thaw originally proposed did not get merged, but perhaps
something like this would be useful in emergencies.

For example, freeze /path/to/mountpoint may freeze your root filesystem if
you forgot that you had that unmounted.

I chose 'j' as the last remaining character other than 'h' which is sort
of reserved for help (because help is generated on any unknown character).

I've tested this on a non-root fs with multiple (nested) freezers, as well
as on a system rendered unresponsive due to a frozen root fs.

[randy.dunlap@oracle.com: emergency thaw only if CONFIG_BLOCK enabled]
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Takashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:17 -07:00
..
ABI Merge branch 'master' into next 2009-03-24 10:52:46 +11:00
accounting Documentation/accounting/getdelays.c: fix endless loop 2009-01-15 16:39:37 -08:00
acpi ACPI: update debug parameter documentation 2008-11-07 21:45:29 -05:00
aoe aoe: user can ask driver to forget previously detected devices 2008-02-08 09:22:31 -08:00
arm Merge branch 'next-s3c-pm' of git://aeryn.fluff.org.uk/bjdooks/linux into devel 2009-03-26 22:44:43 +00:00
auxdisplay .gitignore updates 2008-10-30 11:38:45 -07:00
blackfin Blackfin arch: Add document about bfin-gpio 2009-01-07 23:14:38 +08:00
block block: Repeated lines in switching-sched.txt 2009-03-26 11:01:28 +01:00
blockdev Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
cdrom doc/cdrom: Trvial documentation error, file not present 2008-10-10 08:22:44 +02:00
cgroups cpuset: various documentation fixes and updates 2009-02-20 17:57:49 -08:00
connector Documentation/connector/cn_test.c: don't use gfp_any() 2009-02-12 16:47:01 -08:00
console Typo: fro -> from 2007-07-19 10:04:47 -07:00
cpu-freq [CPUFREQ] ondemand/conservative: sanitize sampling_rate restrictions 2009-02-24 22:47:31 -05:00
cpuidle cpuidle: Add Documentation 2008-02-14 00:16:13 -05:00
cris fix random typos 2008-10-16 11:21:30 -07:00
crypto async_tx, dmaengine: document channel allocation and api rework 2009-01-05 18:10:19 -07:00
development-process Fix a typo in the development process document. 2009-01-08 16:32:13 -07:00
device-mapper dm crypt: add documentation 2008-04-25 13:27:03 +01:00
DocBook proc 2/2: remove struct proc_dir_entry::owner 2009-03-31 01:14:44 +04:00
driver-model PATCH [1/2] Documentation/driver-model/device.txt: fix struct device_attribute 2009-02-22 09:27:15 -08:00
dvb V4L/DVB (11138): get_dvb_firmware: add support for downloading the cx2584x firmware for pvrusb2 2009-03-30 12:43:31 -03:00
early-userspace Documentation: Remove last references to BitKeeper. 2008-04-21 22:19:05 +00:00
fault-injection fault-injection: fix example scripts in documentation 2007-07-16 09:05:45 -07:00
fb [ARM] pxafb: add support for overlay1 and overlay2 as framebuffer devices 2008-12-29 18:00:04 +08:00
filesystems mm: page_mkwrite change prototype to match fault 2009-04-01 08:59:14 -07:00
firmware_class firmware_sample_driver.c: fix coding style 2008-04-21 22:23:30 +00:00
frv move frv docs one level up 2008-02-03 15:54:28 +02:00
hwmon hwmon: Define a standard interface for chassis intrusion detection 2009-03-30 21:46:44 +02:00
i2c Move the pcf8591 driver to hwmon 2009-03-30 21:46:43 +02:00
i2o documentation: convert the Documentation directory to UTF-8 2007-05-09 08:58:19 +02:00
ia64 .gitignore updates 2008-10-30 11:38:45 -07:00
ide ide: update warm-plug HOWTO 2009-01-06 17:21:00 +01:00
infiniband IB/umad: Add P_Key index support 2007-10-09 19:59:15 -07:00
input Merge commit 'v2.6.28-rc9' into next 2008-12-20 04:54:54 -05:00
ioctl V4L/DVB (10870a): remove all references for video_decoder.h 2009-03-30 12:43:15 -03:00
isdn Rationalise Randy's address a bit 2008-10-30 11:38:47 -07:00
ja_JP Sync patch for jp_JP/stable_kernel_rules.txt 2009-01-28 15:55:48 -08:00
kbuild kbuild: fix kbuild.txt typos 2009-01-14 21:42:51 +01:00
kdump powerpc: Support for relocatable kdump kernel 2008-10-22 15:01:22 +11:00
ko_KR HOWTO: update misspelling and word incorrected 2007-12-17 10:33:19 -08:00
laptops ACPI: thinkpad-acpi: bump up version to 0.22 2009-01-15 13:48:24 -05:00
lguest lguest: barrier me harder 2009-03-30 21:55:26 +10:30
m68k [SCSI] 53c7xx: fix removal fallout 2008-01-11 18:22:30 -06:00
make Documentation/make/headers_install.txt 2007-10-17 08:43:05 -07:00
mips ide: remove unused CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ 2009-01-14 19:19:03 +01:00
mn10300 mn10300: add the MN10300/AM33 architecture to the kernel 2008-02-08 09:22:30 -08:00
mtd [MTD] [NAND] nand_ecc.c: rewrite for improved performance 2008-08-16 10:55:33 +01:00
namespaces The namespaces compatibility list doc 2007-11-29 09:24:53 -08:00
netlabel Fix occurrences of "the the " 2007-05-09 08:57:56 +02:00
networking ipv6: Fix incorrect disable_ipv6 behavior 2009-03-18 18:22:48 -07:00
parisc
PCI PCI: Documentation: fix minor PCIe HOWTO thinko 2009-02-13 13:59:19 -08:00
pcmcia .gitignore updates 2008-10-30 11:38:45 -07:00
power pm: document use of RTC in pm_trace 2008-10-16 11:21:29 -07:00
powerpc Merge commit 'origin/master' into next 2009-03-30 14:04:53 +11:00
prctl generic, x86: add tests for prctl PR_GET_TSC and PR_SET_TSC 2008-04-19 19:19:55 +02:00
RCU rcu: documentation 1Q09 update 2009-03-10 15:55:11 -07:00
s390 documentation: update s390 header file paths 2009-01-06 15:59:28 -08:00
scheduler sched, documentation: remove old O(1) scheduler document 2009-03-02 12:02:52 +01:00
scsi [SCSI] osd: Documentation for OSD library 2009-03-12 12:58:09 -05:00
serial Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
sh sh: Kill off remaining CONFIG_SH_KGDB bits. 2008-12-22 18:44:05 +09:00
sound Merge branch 'topic/oxygen' into for-linus 2009-03-24 00:36:17 +01:00
sparc sparc: Remove Documentation/sparc/sbus_drivers.txt 2008-08-29 02:15:25 -07:00
spi hwmon: (lm70) Code streamlining and cleanup 2009-01-07 16:37:34 +01:00
sysctl Update of Documentation: vm.txt and proc.txt 2009-01-15 16:39:35 -08:00
telephony remove mention of CONFIG_KMOD from documentation 2008-07-22 19:24:29 +10:00
thermal thermal: update the documentation 2008-04-29 02:49:47 -04:00
timers hpet: /dev/hpet - fixes and cleanup 2008-07-31 18:45:41 +02:00
tracers doc: mmiotrace.txt, buffer size control change 2009-02-15 20:05:13 +01:00
uml Fix typos in /Documentation : 'U-Z' 2006-11-30 04:58:40 +01:00
usb USB: usbmon: Add binary API v1 2009-03-24 16:20:36 -07:00
video4linux V4L/DVB (11225): v4lgrab: fix compilation warnings 2009-03-30 12:43:41 -03:00
vm mm: remove try_to_munlock from vmscan 2009-01-06 15:59:03 -08:00
w1 w1: send status messages after command processing 2009-01-08 08:31:14 -08:00
watchdog .gitignore updates 2008-10-30 11:38:45 -07:00
wimax i2400m: documentation and instructions for usage 2009-01-07 10:00:18 -08:00
x86 Merge branch 'x86/doc' into x86/core 2009-03-05 21:49:44 +01:00
zh_CN Chinese: add translation of Codingstyle 2008-01-24 20:40:04 -08:00
00-INDEX Merge branch 'doc-subdirs' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs 2008-11-15 11:51:03 -08:00
applying-patches.txt
atomic_ops.txt documentation: atomic_add_unless() doesn't imply mb() on failure 2008-02-23 17:52:36 -08:00
bad_memory.txt Document handling of bad memory 2008-12-03 16:09:53 -07:00
basic_profiling.txt
binfmt_misc.txt documentation: convert the Documentation directory to UTF-8 2007-05-09 08:58:19 +02:00
braille-console.txt Basic braille screen reader support 2008-04-30 08:29:52 -07:00
bt8xxgpio.txt gpio: add bt8xxgpio driver 2008-07-25 10:53:30 -07:00
BUG-HUNTING Documentation: add hint about call traces & module symbols to BUG-HUNTING 2008-02-06 10:41:09 -08:00
c2port.txt Add c2 port support 2008-11-12 17:17:18 -08:00
cachetlb.txt remove unused flush_tlb_pgtables 2007-10-19 11:53:34 -07:00
Changes Documentation/Changes: add required versions for new filesystems 2009-01-29 18:19:30 -08:00
CodingStyle fix emacs indenting howto filename expansion 2009-01-29 18:19:29 -08:00
cpu-hotplug.txt x86: use possible_cpus=NUM to extend the possible cpus allowed 2008-12-18 12:08:05 +01:00
cpu-load.txt [PATCH] Documentation: CPU load calculation description 2007-03-01 14:53:39 -08:00
cputopology.txt cpumask: Use topology_core_cpumask()/topology_thread_cpumask() 2009-01-11 19:12:49 +01:00
credentials.txt CRED: Documentation 2008-11-14 10:39:26 +11:00
dcdbas.txt
debugging-modules.txt Documentation: Clarify when module debugging actually works. 2008-02-03 15:27:38 +02:00
debugging-via-ohci1394.txt firewire: fw-ohci: add option for remote debugging 2008-04-18 17:55:33 +02:00
dell_rbu.txt trivial: fix an -> a typos in documentation and comments 2009-01-06 11:28:07 +01:00
devices.txt [SCSI] major.h: char-major number for OSD device driver 2009-03-12 12:58:05 -05:00
DMA-API.txt dma-debug: Documentation update 2009-03-17 12:56:47 +01:00
DMA-attributes.txt powerpc/cell: Add DMA_ATTR_WEAK_ORDERING dma attribute and use in Cell IOMMU code 2008-07-22 10:39:36 +10:00
DMA-ISA-LPC.txt Fix typos in /Documentation : 'T'' 2006-11-30 04:55:36 +01:00
DMA-mapping.txt documentation: update header file paths 2009-01-06 15:59:28 -08:00
dmaengine.txt async_tx, dmaengine: document channel allocation and api rework 2009-01-05 18:10:19 -07:00
dontdiff dontdiff: Fix asm exclude 2009-03-26 15:45:43 -07:00
dynamic-debug-howto.txt Dynamic debug: allow simple quoting of words 2009-03-24 16:38:27 -07:00
edac.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
eisa.txt Fix typos in /Documentation : 'U-Z' 2006-11-30 04:58:40 +01:00
email-clients.txt Documentation/email-clients.txt: add some info about gmail 2008-11-06 15:41:19 -08:00
exception.txt Documentation: remove duplicated words 2006-10-03 22:57:56 +02:00
feature-removal-schedule.txt mm: reintroduce and deprecate rlimit based access for SHM_HUGETLB 2009-04-01 08:59:12 -07:00
ftrace.txt ftrace: improve documentation 2008-11-28 13:15:14 +01:00
gpio.txt gpiolib: request/free hooks 2008-10-16 11:21:40 -07:00
highuid.txt [SPARC]: Remove SunOS and Solaris binary support. 2008-04-21 15:10:15 -07:00
HOWTO Remove Andrew Morton's http://www.zip.com.au/~akpm/ 2008-10-16 11:21:32 -07:00
hw_random.txt hw_random doc updates 2008-03-24 19:22:19 -07:00
ics932s401 ics932s401: new clock generator chip driver 2008-11-12 17:17:18 -08:00
initrd.txt use the newc archive format as requested by initramfs 2008-02-03 14:54:41 +02:00
Intel-IOMMU.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
io_ordering.txt
io-mapping.txt io mapping: improve documentation 2008-11-03 18:21:44 +01:00
IO-mapping.txt Documentation: move DMA-mapping.txt to Doc/PCI/ 2009-01-29 18:19:29 -08:00
iostats.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
IPMI.txt IPMI: new NMI handling 2007-10-18 14:37:32 -07:00
IRQ-affinity.txt genirq: Expose default irq affinity mask (take 3) 2008-06-05 15:18:30 +02:00
IRQ.txt [PATCH] genirq: irq: document what an IRQ is 2006-06-29 10:26:25 -07:00
irqflags-tracing.txt [PATCH] lockdep: irqtrace subsystem, docs 2006-07-03 15:27:03 -07:00
isapnp.txt
java.txt Documentation/java.txt: typo and grammar fixes 2007-10-20 02:37:21 +02:00
kernel-doc-nano-HOWTO.txt kernel-doc: preferred ending marker and examples 2009-02-11 14:25:36 -08:00
kernel-docs.txt doc: update to URL and status of kernel-docs.txt entry 2008-06-06 11:29:10 -07:00
kernel-parameters.txt Merge branch 'iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 13:41:00 -07:00
keys-request-key.txt keys: allow the callout data to be passed as a blob rather than a string 2008-04-29 08:06:16 -07:00
keys.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
kobject.txt kobject: Make Documentation/kobject.txt a little more coherent. 2009-01-06 10:44:32 -08:00
kprobes.txt kprobes: support probing module __exit function 2009-01-06 15:59:21 -08:00
kref.txt docs: convert kref semaphore to mutex 2008-02-06 10:41:09 -08:00
ldm.txt LDM: Fix for Windows Vista dynamic disks 2007-05-21 09:58:40 -07:00
leds-class.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
local_ops.txt documentation: local_ops fix on_each_cpu 2008-12-01 13:51:26 +01:00
lockdep-design.txt lockdep: get_user_chars() redo 2009-02-14 23:28:22 +01:00
lockstat.txt lockstat: contend with points 2008-10-20 15:43:10 +02:00
logo.svg linux.conf.au 2009: Tuz 2009-03-16 07:55:37 -07:00
logo.txt linux.conf.au 2009: Tuz 2009-03-16 07:55:37 -07:00
magic-number.txt documentation: update header file paths 2009-01-06 15:59:28 -08:00
Makefile docsrc: build Documentation/ sources 2008-08-12 16:07:30 -07:00
ManagementStyle docs: fix ManagementStyle book name 2008-10-30 11:38:46 -07:00
markers.txt markers: comment marker_synchronize_unregister() on data dependency 2008-11-28 16:47:41 +01:00
mca.txt The ps2esdi driver was marked as BROKEN more than two years ago due to being 2008-03-17 09:03:05 +01:00
md.txt md: Tidy up rdev_size_store a bit: 2008-07-21 14:22:18 +10:00
memory-barriers.txt read_barrier_depends arch fixlets 2008-05-14 10:05:18 -07:00
memory-hotplug.txt mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
memory.txt
mono.txt Fix "can not" in Documentation and Kconfig 2006-10-03 22:53:09 +02:00
mutex-design.txt Documentation: Add nested versions of mutex locks to docs 2007-10-20 00:15:26 +02:00
nmi_watchdog.txt x86, nmi-watchdog: update procfs nmi_watchdog file documentation v2 2008-10-30 19:07:04 +01:00
nommu-mmap.txt NOMMU: Make mmap allocation page trimming behaviour configurable. 2009-01-08 12:04:47 +00:00
numastat.txt
oops-tracing.txt Taint kernel after WARN_ON(condition) 2008-04-29 08:05:59 -07:00
parport-lowlevel.txt plip: fix parport_register_device name parameter 2007-11-26 19:39:01 -08:00
parport.txt
pi-futex.txt fix a typo in Documentation/pi-futex.txt 2006-10-03 23:39:02 +02:00
pnp.txt Documentation: Replace obsolete "driverfs" with "sysfs". 2008-01-24 20:40:04 -08:00
preempt-locking.txt
printk-formats.txt DOC: add printk-formats.txt 2008-11-12 17:17:17 -08:00
prio_tree.txt Documentation: remove duplicated words 2006-10-03 22:57:56 +02:00
rbtree.txt [PATCH] Documentation/rbtree.txt 2007-02-11 10:51:35 -08:00
rfkill.txt rfkill: add master_switch_mode and EPO lock to rfkill and rfkill-input 2008-10-31 19:00:09 -04:00
robust-futex-ABI.txt Fix typos in /Documentation : 'U-Z' 2006-11-30 04:58:40 +01:00
robust-futexes.txt Fix typos in /Documentation : Misc 2006-11-30 05:21:10 +01:00
rt-mutex-design.txt [PATCH] typo fixes for rt-mutex-design.txt 2006-10-01 00:39:24 -07:00
rt-mutex.txt [PATCH] pi-futex: rt mutex docs 2006-06-27 17:32:47 -07:00
rtc.txt rtc: cleanup example code 2008-02-06 10:41:14 -08:00
SAK.txt Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
SecurityBugs
SELinux.txt selinux: add support for installing a dummy policy (v2) 2008-08-27 08:54:08 +10:00
serial-console.txt [PATCH] doc: more serial-console info 2006-03-25 08:23:00 -08:00
sgi-ioc4.txt
sgi-visws.txt
SM501.txt Tweak Documentation/SM501.txt 2007-10-17 08:43:06 -07:00
Smack.txt smack: Add a new '-CIPSO' option to the network address label configuration 2009-03-28 15:01:37 +11:00
sparse.txt kbuild: sparse needs CF not CHECKFLAGS 2008-07-25 22:12:39 +02:00
spinlocks.txt Add additional examples in Documentation/spinlocks.txt 2008-04-11 13:21:14 -06:00
stable_api_nonsense.txt stable_api_nonsense.txt: Disambiguate the use of "this" by using "that" to refer to the syscall interface 2007-07-30 14:25:12 -07:00
stable_kernel_rules.txt Update stable tree documentation 2008-10-29 15:03:49 -07:00
SubmitChecklist documentation: explain memory barriers 2008-10-16 11:21:32 -07:00
SubmittingDrivers Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
SubmittingPatches Merge branch 'docs' of git://git.lwn.net/linux-2.6 2008-10-16 12:18:16 -07:00
svga.txt
sysfs-rules.txt sysfs-rules.txt: reword API stability statement 2008-07-21 21:54:59 -07:00
sysrq.txt filesystem freeze: allow SysRq emergency thaw to thaw frozen filesystems 2009-04-01 08:59:17 -07:00
tracepoints.txt tracepoints: Documentation TPPROTO misspelt in Documentation/tracepoints.txt 2008-11-29 15:13:42 +01:00
unaligned-memory-access.txt introduce HAVE_EFFICIENT_UNALIGNED_ACCESS Kconfig symbol 2008-07-25 10:53:27 -07:00
unicode.txt
unshare.txt Documentation: remove duplicated words 2006-10-03 22:57:56 +02:00
VGA-softcursor.txt
video-output.txt output: Add output class document 2006-12-20 01:46:58 -05:00
volatile-considered-harmful.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
voyager.txt
zorro.txt