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Nick Piggin d996b62a8d tty: fix fu_list abuse 
tty: fix fu_list abuse

tty code abuses fu_list, which causes a bug in remount,ro handling.

If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".

Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.

The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.

[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:47 -04:00
..
agp agp: intel-agp: do not use PCI resources before pci_enable_device() 2010-08-05 12:28:25 +10:00
hw_random of/device: Replace struct of_device with struct platform_device 2010-08-06 09:25:50 -06:00
ip2 tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
ipmi Merge branch 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus 2010-08-12 10:01:59 -07:00
mwave mwave: fix read buffer overflow 2009-09-24 07:21:03 -07:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2010-08-09 21:05:52 -07:00
rio include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
tpm tpm_tis: fix subsequent suspend failures 2010-07-26 10:25:45 +10:00
xilinx_hwicap of/device: Replace struct of_device with struct platform_device 2010-08-06 09:25:50 -06:00
.gitignore
amiserial.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
apm-emulation.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
applicom.c drivers/char/applicom.c: use memdup_user 2010-05-27 09:12:50 -07:00
applicom.h
bfin-otp.c const: constify remaining file_operations 2009-10-01 16:11:11 -07:00
bfin_jtag_comm.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
briq_panel.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
bsr.c of/address: Clean up function declarations 2010-08-01 01:42:42 -06:00
cd1865.h
consolemap.c
cp437.uni
cs5535_gpio.c drivers: Remove BKL from cs5535_gpio 2009-10-14 17:36:48 +02:00
cyclades.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00
defkeymap.c_shipped
defkeymap.map
digi1.h
digiFep1.h
digiPCI.h
ds1302.c
ds1620.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
dsp56k.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
dtlk.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
efirtc.c efirtc: explicitly set llseek to no_llseek 2009-12-16 07:19:59 -08:00
epca.c epca: Kill the big kernel lock 2010-08-10 13:47:40 -07:00
epca.h
epcaconfig.h
generic_nvram.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
generic_serial.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
genrtc.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
hangcheck-timer.c hangcheck-timer: fix x86_32 bugs 2010-05-25 08:07:02 -07:00
hpet.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
hvc_beat.c Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6 2010-02-25 15:38:37 -08:00
hvc_console.c hvc_console: use "*_console" nomenclature to avoid modpost warning. 2010-07-09 11:28:24 +10:00
hvc_console.h hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_irq.c
hvc_iseries.c Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
hvc_iucv.c Add param ops struct for hvc_iucv driver. 2010-08-11 23:04:16 +09:30
hvc_rtas.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_tile.c arch/tile: catch up on various minor cleanups. 2010-07-06 13:42:15 -04:00
hvc_udbg.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_vio.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvc_xen.c hvc_console: make the ops pointer const. 2010-02-24 14:22:32 +10:30
hvcs.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
hvsi.c hvc_console: use "*_console" nomenclature to avoid modpost warning. 2010-07-09 11:28:24 +10:00
i8k.c procfs: Push down the bkl from ioctl 2010-05-17 03:06:12 +02:00
isicom.c isicom: kill off the BKL 2010-08-10 13:47:40 -07:00
istallion.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00
Kconfig pc8736x_gpio: depends on X86_32 2010-08-12 08:43:29 -07:00
keyboard.c tty: Move the vt_tty field from the vc_data into the standard tty_port 2010-08-10 13:47:42 -07:00
lp.c lp: move compat_ioctl handling into lp.c 2009-12-10 22:55:36 +01:00
Makefile tty: implement BTM as mutex instead of BKL 2010-08-10 13:47:44 -07:00
mbcs.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
mbcs.h
mem.c Fix init ordering of /dev/console vs callers of modprobe 2010-08-06 09:17:02 -07:00
misc.c char: add WARN_ON() in misc_deregister() 2010-08-09 20:45:06 -07:00
mmtimer.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
moxa.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
moxa.h
mspec.c tree-wide: fix assorted typos all over the place 2009-12-04 15:39:55 +01:00
mxser.c mxser: remove unnesesary NULL check 2010-08-10 13:47:45 -07:00
mxser.h
n_gsm.c drivers/char/n_gsm.c: add missing spin_unlock_irqrestore 2010-08-11 08:59:20 -07:00
n_hdlc.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
n_r3964.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00
n_tty.c tty: Add EXTPROC support for LINEMODE 2010-08-10 13:47:39 -07:00
nozomi.c kfifo: fix kfifo miss use of nozami.c 2010-08-11 08:59:23 -07:00
nsc_gpio.c
nvram.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
nwbutton.c
nwbutton.h
nwflash.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
pc8736x_gpio.c drivers: Remove BKL from pc8736x_gpio 2009-10-14 17:36:52 +02:00
ppdev.c drivers/char/ppdev.c: use kasprintf 2010-05-27 09:12:50 -07:00
ps3flash.c drop unused dentry argument to ->fsync 2010-05-27 22:05:02 -04:00
pty.c tty: fix fu_list abuse 2010-08-18 08:35:47 -04:00
ramoops.c char drivers: RAM oops/panic logger 2010-05-27 09:12:50 -07:00
random.c random: Reorder struct entropy_store to remove padding on 64bits 2010-07-31 19:58:00 +08:00
raw.c drivers: Push down BKL into various drivers 2010-05-17 05:27:41 +02:00
riscom8.c riscom8: kill use of lock_kernel 2010-08-10 13:47:40 -07:00
riscom8.h
riscom8_reg.h
rocket.c rocket: kill BKL 2010-08-10 13:47:40 -07:00
rocket.h
rocket_int.h
rtc.c of/device: Replace struct of_device with struct platform_device 2010-08-06 09:25:50 -06:00
scc.h
scx200_gpio.c drivers: Remove BKL from scx200_gpio 2009-10-14 17:36:53 +02:00
selection.c tty: remove tty_lock_nested 2010-08-10 13:47:44 -07:00
ser_a2232.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
ser_a2232.h
ser_a2232fw.ax
ser_a2232fw.h
serial167.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
snsc.c
snsc.h
snsc_event.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sonypi.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
specialix.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
specialix_io8.h
stallion.c stallion: prune lock_kernel calls 2010-08-10 13:47:40 -07:00
sx.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
sx.h
sxboards.h
sxwindow.h
synclink.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
synclink_gt.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
synclinkmp.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
sysrq.c sysrq,kdb: Use __handle_sysrq() for kdb's sysrq function 2010-07-21 19:27:07 -05:00
tb0219.c mips: Remove BKL from tb0219 2009-10-14 17:36:53 +02:00
tlclk.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
toshiba.c tosh: Use non bkl ioctl 2010-01-04 12:31:21 -08:00
tty_audit.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
tty_buffer.c tty: fix obsolete comment on tty_insert_flip_string_fixed_flag 2010-05-21 09:34:30 -07:00
tty_io.c tty: fix fu_list abuse 2010-08-18 08:35:47 -04:00
tty_ioctl.c tty: Add EXTPROC support for LINEMODE 2010-08-10 13:47:39 -07:00
tty_ldisc.c tty: remove tty_lock_nested 2010-08-10 13:47:44 -07:00
tty_mutex.c tty: implement BTM as mutex instead of BKL 2010-08-10 13:47:44 -07:00
tty_port.c tty: release BTM while sleeping in block_til_ready 2010-08-10 13:47:44 -07:00
uv_mmtimer.c x86, UV: Fix RTC latency bug by reading replicated cachelines 2010-01-27 11:33:53 +01:00
vc_screen.c tty: replace BKL with a new tty_lock 2010-08-10 13:47:43 -07:00
viotape.c of: Always use 'struct device.of_node' to get device node pointer. 2010-05-18 16:10:44 -06:00
virtio_console.c virtio: console: Fix crash when port is unplugged and blocked for write 2010-06-03 22:39:19 +09:30
vme_scc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
vt.c tty: Move the vt_tty field from the vc_data into the standard tty_port 2010-08-10 13:47:42 -07:00
vt_ioctl.c tty: introduce wait_event_interruptible_tty 2010-08-10 13:47:43 -07:00