If ->writepage() tries to write back a page whose copy is still in flight,
then just skip by calling redirty_page_for_writepage().
This is OK, since now ->writepage() should never be called for data
integrity sync.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
As Maxim Patlasov pointed out, it's possible to get a dirty page while it's
copy is still under writeback, despite fuse_page_mkwrite() doing its thing
(direct IO).
This could result in two concurrent write request for the same offset, with
data corruption if they get mixed up.
To prevent this, fuse needs to check and delay such writes. This
implementation does this by:
1. check if page is still under writeout, if so create a new, single page
secondary request for it
2. chain this secondary request onto the in-flight request
2/a. if a seconday request for the same offset was already chained to the
in-flight request, then just copy the contents of the page and discard
the new secondary request. This makes sure that for each page will
have at most two requests associated with it
3. when the in-flight request finished, send off all secondary requests
chained onto it
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Checking against tmp-page indexes is not very useful, and results in one
(or rarely two) page requests. Which is not much of an improvement...
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
The patch fixes a race between ftruncate(2), mmap-ed write and write(2):
1) An user makes a page dirty via mmap-ed write.
2) The user performs shrinking truncate(2) intended to purge the page.
3) Before fuse_do_setattr calls truncate_pagecache, the page goes to
writeback. fuse_writepages_fill attaches a new page to FUSE_WRITE request,
then releases the original page by end_page_writeback and unlock it.
4) fuse_do_setattr completes and successfully returns. Since now, i_mutex
is free.
5) Ordinary write(2) extends i_size back to cover the page. Note that
fuse_send_write_pages do wait for fuse writeback, but for another
page->index.
6) fuse_writepages_fill attaches more pages to the request (if any), then
fuse_writepages_send is eventually called. It is supposed to crop
inarg->size of the request, but it doesn't because i_size has already been
extended back.
Moving end_page_writeback behind fuse_writepages_send guarantees that
__fuse_release_nowrite (called from fuse_do_setattr) will crop inarg->size
of the request before write(2) gets the chance to extend i_size.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
The .writepages one is required to make each writeback request carry more than
one page on it. The patch enables optimized behaviour unconditionally,
i.e. mmap-ed writes will benefit from the patch even if fc->writeback_cache=0.
[SzM: simplify, add comments]
Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Don't bug if there's no writable files found for page writeback. If ever
this is triggered, a WARN_ON helps debugging it much better then a BUG_ON.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Lock the page in fuse_page_mkwrite() to protect against a race with
fuse_writepage() where the page is redirtied before the actual writeback
begins.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
The .writepages callback will issue writeback requests with more than one
page aboard. Make existing end/check code be aware of this.
Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
There will be a .writepageS callback implementation which will need to
get a fuse_file out of a fuse_inode, thus make a helper for this.
Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Doing dput(parent) is not valid in RCU walk mode. In RCU mode it would
probably be okay to update the parent flags, but it's actually not
necessary most of the time...
So only set the FUSE_I_ADVISE_RDPLUS flag on the parent when the entry was
recently initialized by READDIRPLUS.
This is achieved by setting FUSE_I_INIT_RDPLUS on entries added by
READDIRPLUS and only dropping out of RCU mode if this flag is set.
FUSE_I_INIT_RDPLUS is cleared once the FUSE_I_ADVISE_RDPLUS flag is set in
the parent.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
If revalidate finds an invalid dentry in RCU walk mode, let the VFS deal
with it instead of calling check_submounts_and_drop() which is not prepared
for being called from RCU walk.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
A former patch introducing FUSE_I_SIZE_UNSTABLE flag provided detailed
description of races between ftruncate and anyone who can extend i_size:
> 1. As in the previous scenario fuse_dentry_revalidate() discovered that i_size
> changed (due to our own fuse_do_setattr()) and is going to call
> truncate_pagecache() for some 'new_size' it believes valid right now. But by
> the time that particular truncate_pagecache() is called ...
> 2. fuse_do_setattr() returns (either having called truncate_pagecache() or
> not -- it doesn't matter).
> 3. The file is extended either by write(2) or ftruncate(2) or fallocate(2).
> 4. mmap-ed write makes a page in the extended region dirty.
This patch adds necessary bits to fuse_file_fallocate() to protect from that
race.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
The patch fixes a race between mmap-ed write and fallocate(PUNCH_HOLE):
1) An user makes a page dirty via mmap-ed write.
2) The user performs fallocate(2) with mode == PUNCH_HOLE|KEEP_SIZE
and <offset, size> covering the page.
3) Before truncate_pagecache_range call from fuse_file_fallocate,
the page goes to write-back. The page is fully processed by fuse_writepage
(including end_page_writeback on the page), but fuse_flush_writepages did
nothing because fi->writectr < 0.
4) truncate_pagecache_range is called and fuse_file_fallocate is finishing
by calling fuse_release_nowrite. The latter triggers processing queued
write-back request which will write stale data to the hole soon.
Changed in v2 (thanks to Brian for suggestion):
- Do not truncate page cache until FUSE_FALLOCATE succeeded. Otherwise,
we can end up in returning -ENOTSUPP while user data is already punched
from page cache. Use filemap_write_and_wait_range() instead.
Changed in v3 (thanks to Miklos for suggestion):
- fuse_wait_on_writeback() is prone to livelocks; use fuse_set_nowrite()
instead. So far as we need a dirty-page barrier only, fuse_sync_writes()
should be enough.
- rebased to for-linus branch of fuse.git
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
Pull timer code update from Thomas Gleixner:
- armada SoC clocksource overhaul with a trivial merge conflict
- Minor improvements to various SoC clocksource drivers
* 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource: armada-370-xp: Add detailed clock requirements in devicetree binding
clocksource: armada-370-xp: Get reference fixed-clock by name
clocksource: armada-370-xp: Replace WARN_ON with BUG_ON
clocksource: armada-370-xp: Fix device-tree binding
clocksource: armada-370-xp: Introduce new compatibles
clocksource: armada-370-xp: Use CLOCKSOURCE_OF_DECLARE
clocksource: armada-370-xp: Simplify TIMER_CTRL register access
clocksource: armada-370-xp: Use BIT()
ARM: timer-sp: Set dynamic irq affinity
ARM: nomadik: add dynamic irq flag to the timer
clocksource: sh_cmt: 32-bit control register support
clocksource: em_sti: Convert to devm_* managed helpers
Pull CIFS fixes from Steve French:
"Two minor cifs fixes and a minor documentation cleanup for cifs.txt"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
cifs: update cifs.txt and remove some outdated infos
cifs: Avoid calling unlock_page() twice in cifs_readpage() when using fscache
cifs: Do not take a reference to the page in cifs_readpage_worker()
Pull UBI fixes from Artem Bityutskiy:
"Just a single fastmap fix plus a regression fix"
* tag 'upstream-3.12-rc1' of git://git.infradead.org/linux-ubi:
UBI: Fix invalidate_fastmap()
UBI: Fix PEB leak in wear_leveling_worker()
Pull ubifs fix from Artem Bityutskiy:
"Just one patch which fixes the power-cut recovery testing mode.
I'll start using a single UBI/UBIFS tree instead of 2 trees from now
on. So in the future you'll get 1 small pull request instead of 2
tiny ones"
* tag 'upstream-3.12-rc1' of git://git.infradead.org/linux-ubifs:
UBIFS: remove invalid warn msg with tst_recovery enabled
Pull MIPS fixes from Ralf Baechle:
"These are four patches for three construction sites:
- Fix register decoding for the combination of multi-core processors
and multi-threading.
- Two more fixes that are part of the ongoing DECstation resurrection
work. One of these touches a DECstation-only network driver.
- Finally Markos' trivial build fix for the AP/SP support.
(With this applied now all MIPS defconfigs are building again)"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MIPS: kernel: vpe: Make vpe_attrs an array of pointers.
MIPS: Fix SMP core calculations when using MT support.
MIPS: DECstation I/O ASIC DMA interrupt handling fix
MIPS: DECstation HRT initialization rearrangement
Pull x86 platform updates from Matthew Garrett:
"Nothing amazing here, almost entirely cleanups and minor bugfixes and
one bit of hardware enablement in the amilo-rfkill driver"
* 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86:
platform/x86: panasonic-laptop: reuse module_acpi_driver
samsung-laptop: fix config build error
platform: x86: remove unnecessary platform_set_drvdata()
amilo-rfkill: Enable using amilo-rfkill with the FSC Amilo L1310.
wmi: parse_wdg() should return kernel error codes
hp_wmi: Fix unregister order in hp_wmi_rfkill_setup()
platform: replace strict_strto*() with kstrto*()
x86: irst: use module_acpi_driver to simplify the code
x86: smartconnect: use module_acpi_driver to simplify the code
platform samsung-q10: use ACPI instead of direct EC calls
thinkpad_acpi: add the ability setting TPACPI_LED_NONE by quirk
thinkpad_acpi: return -NODEV while operating uninitialized LEDs
Pull misc SCSI driver updates from James Bottomley:
"This patch set is a set of driver updates (megaraid_sas, fnic, lpfc,
ufs, hpsa) we also have a couple of bug fixes (sd out of bounds and
ibmvfc error handling) and the first round of esas2r checker fixes and
finally the much anticipated big endian additions for megaraid_sas"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (47 commits)
[SCSI] fnic: fnic Driver Tuneables Exposed through CLI
[SCSI] fnic: Kernel panic while running sh/nosh with max lun cfg
[SCSI] fnic: Hitting BUG_ON(io_req->abts_done) in fnic_rport_exch_reset
[SCSI] fnic: Remove QUEUE_FULL handling code
[SCSI] fnic: On system with >1.1TB RAM, VIC fails multipath after boot up
[SCSI] fnic: FC stat param seconds_since_last_reset not getting updated
[SCSI] sd: Fix potential out-of-bounds access
[SCSI] lpfc 8.3.42: Update lpfc version to driver version 8.3.42
[SCSI] lpfc 8.3.42: Fixed issue of task management commands having a fixed timeout
[SCSI] lpfc 8.3.42: Fixed inconsistent spin lock usage.
[SCSI] lpfc 8.3.42: Fix driver's abort loop functionality to skip IOs already getting aborted
[SCSI] lpfc 8.3.42: Fixed failure to allocate SCSI buffer on PPC64 platform for SLI4 devices
[SCSI] lpfc 8.3.42: Fix WARN_ON when driver unloads
[SCSI] lpfc 8.3.42: Avoided making pci bar ioremap call during dual-chute WQ/RQ pci bar selection
[SCSI] lpfc 8.3.42: Fixed driver iocbq structure's iocb_flag field running out of space
[SCSI] lpfc 8.3.42: Fix crash on driver load due to cpu affinity logic
[SCSI] lpfc 8.3.42: Fixed logging format of setting driver sysfs attributes hard to interpret
[SCSI] lpfc 8.3.42: Fixed back to back RSCNs discovery failure.
[SCSI] lpfc 8.3.42: Fixed race condition between BSG I/O dispatch and timeout handling
[SCSI] lpfc 8.3.42: Fixed function mode field defined too small for not recognizing dual-chute mode
...
Pull SLAB update from Pekka Enberg:
"Nothing terribly exciting here apart from Christoph's kmalloc
unification patches that brings sl[aou]b implementations closer to
each other"
* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
slab: Use correct GFP_DMA constant
slub: remove verify_mem_not_deleted()
mm/sl[aou]b: Move kmallocXXX functions to common code
mm, slab_common: add 'unlikely' to size check of kmalloc_slab()
mm/slub.c: beautify code for removing redundancy 'break' statement.
slub: Remove unnecessary page NULL check
slub: don't use cpu partial pages on UP
mm/slub: beautify code for 80 column limitation and tab alignment
mm/slub: remove 'per_cpu' which is useless variable
Pull input update from Dmitry Torokhov:
"The only change is David Hermann's new EVIOCREVOKE evdev ioctl that
allows safely passing file descriptors to input devices to session
processes and later being able to stop delivery of events through
these fds so that inactive sessions will no longer receive user input
that does not belong to them"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: evdev - add EVIOCREVOKE ioctl
Sedat points out that I transposed some letters in "LRU" and wrote "RLU"
instead in one of the new comments explaining the flow. Let's just fix
it.
Reported-by: Sedat Dilek <sedat.dilek@jpberlin.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miklos Szeredi
Maxim Patlasov
Pavel Emelyanov
Linus Torvalds