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git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm fixes from Dan Williams:
"A couple of fixes for long standing bugs, a warning fixup, and some
miscellaneous dax cleanups.
The bugs were recently found due to new platforms looking to use the
ACPI NFIT "virtual" device definition, and new error injection
capabilities to trigger error responses to label area requests. Ira's
cleanups have been long pending, I neglected to send them earlier, and
see no harm in including them now. This has all appeared in -next with
no reported issues.
Summary:
- Fix support for NFIT "virtual" ranges (BIOS-defined memory disks)
- Fix recovery from failed label storage areas on NVDIMM devices
- Miscellaneous cleanups from Ira's investigation of
dax_direct_access paths preparing for stray-write protection"
* tag 'libnvdimm-fixes-5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
tools/testing/nvdimm: Fix missing 'fallthrough' warning
libnvdimm/region: Fix label activation vs errors
ACPI: NFIT: Fix support for virtual SPA ranges
dax: Ensure errno is returned from dax_direct_access
fs/dax: Clarify nr_pages to dax_direct_access()
fs/fuse: Remove unneeded kaddr parameter
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Pick up some small dax cleanups that make some of Ira's follow on work
easier.
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dax_direct_access() takes a number of pages. PHYS_PFN(PAGE_SIZE) is a
very round about way to specify '1'.
Change the nr_pages parameter to the explicit value of '1'.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20210525172428.3634316-3-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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fuse_dax_mem_range_init() does not need the address or the pfn of the
memory requested in dax_direct_access(). It is only calling direct
access to get the number of pages.
Remove the unused variables and stop requesting the kaddr and pfn from
dax_direct_access().
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
Link: https://lore.kernel.org/r/20210525172428.3634316-2-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Pull configfs fix from Christoph Hellwig:
- fix to revert to the historic write behavior (Bart Van Assche)
* tag 'configfs-5.14' of git://git.infradead.org/users/hch/configfs:
configfs: restore the kernel v5.13 text attribute write behavior
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Instead of appending new text attribute data at the offset specified by the
write() system call, only pass the newly written data to the .store()
callback.
Reported-by: Bodo Stroesser <bostroesser@gmail.com>
Tested-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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Pull cifs fixes from Steve French:
"Four CIFS/SMB3 Fixes, all for stable, two relating to deferred close,
and one for the 'modefromsid' mount option (when 'idsfromsid' not
specified)"
* tag '5.14-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: Call close synchronously during unlink/rename/lease break.
cifs: Handle race conditions during rename
cifs: use the correct max-length for dentry_path_raw()
cifs: create sd context must be a multiple of 8
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During unlink/rename/lease break, deferred work for close is
scheduled immediately but in an asynchronous manner which might
lead to race with actual(unlink/rename) commands.
This change will schedule close synchronously which will avoid
the race conditions with other commands.
Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org # 5.13
Signed-off-by: Steve French <stfrench@microsoft.com>
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When rename is executed on directory which has files for which
close is deferred, then rename will fail with EACCES.
This patch will try to close all deferred files when EACCES is received
and retry rename on a directory.
Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Cc: stable@vger.kernel.org # 5.13
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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RHBZ: 1972502
PATH_MAX is 4096 but PAGE_SIZE can be >4096 on some architectures
such as ppc and would thus write beyond the end of the actual object.
Cc: <stable@vger.kernel.org>
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Suggested-by: Brian foster <bfoster@redhat.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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We used to follow the rule earlier that the create SD context
always be a multiple of 8. However, with the change:
cifs: refactor create_sd_buf() and and avoid corrupting the buffer
...we recompute the length, and we failed that rule.
Fixing that with this change.
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Pull io_uring fixes from Jens Axboe:
"A bit bigger than the previous weeks, but mostly just a few stable
bound fixes. In detail:
- Followup fixes to patches from last week for io-wq, turns out they
weren't complete (Hao)
- Two lockdep reported fixes out of the RT camp (me)
- Sync the io_uring-cp example with liburing, as a few bug fixes
never made it to the kernel carried version (me)
- SQPOLL related TIF_NOTIFY_SIGNAL fix (Nadav)
- Use WRITE_ONCE() when writing sq flags (Nadav)
- io_rsrc_put_work() deadlock fix (Pavel)"
* tag 'io_uring-5.14-2021-08-13' of git://git.kernel.dk/linux-block:
tools/io_uring/io_uring-cp: sync with liburing example
io_uring: fix ctx-exit io_rsrc_put_work() deadlock
io_uring: drop ctx->uring_lock before flushing work item
io-wq: fix IO_WORKER_F_FIXED issue in create_io_worker()
io-wq: fix bug of creating io-wokers unconditionally
io_uring: rsrc ref lock needs to be IRQ safe
io_uring: Use WRITE_ONCE() when writing to sq_flags
io_uring: clear TIF_NOTIFY_SIGNAL when running task work
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__io_rsrc_put_work() might need ->uring_lock, so nobody should wait for
rsrc nodes holding the mutex. However, that's exactly what
io_ring_ctx_free() does with io_wait_rsrc_data().
Split it into rsrc wait + dealloc, and move the first one out of the
lock.
Cc: stable@vger.kernel.org
Fixes: b60c8dce33895 ("io_uring: preparation for rsrc tagging")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0130c5c2693468173ec1afab714e0885d2c9c363.1628559783.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ammar reports that he's seeing a lockdep splat on running test/rsrc_tags
from the regression suite:
======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc3-bluetea-test-00249-gc7d102232649 #5 Tainted: G OE
------------------------------------------------------
kworker/2:4/2684 is trying to acquire lock:
ffff88814bb1c0a8 (&ctx->uring_lock){+.+.}-{3:3}, at: io_rsrc_put_work+0x13d/0x1a0
but task is already holding lock:
ffffc90001c6be70 ((work_completion)(&(&ctx->rsrc_put_work)->work)){+.+.}-{0:0}, at: process_one_work+0x1bc/0x530
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 ((work_completion)(&(&ctx->rsrc_put_work)->work)){+.+.}-{0:0}:
__flush_work+0x31b/0x490
io_rsrc_ref_quiesce.part.0.constprop.0+0x35/0xb0
__do_sys_io_uring_register+0x45b/0x1060
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #0 (&ctx->uring_lock){+.+.}-{3:3}:
__lock_acquire+0x119a/0x1e10
lock_acquire+0xc8/0x2f0
__mutex_lock+0x86/0x740
io_rsrc_put_work+0x13d/0x1a0
process_one_work+0x236/0x530
worker_thread+0x52/0x3b0
kthread+0x135/0x160
ret_from_fork+0x1f/0x30
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((work_completion)(&(&ctx->rsrc_put_work)->work));
lock(&ctx->uring_lock);
lock((work_completion)(&(&ctx->rsrc_put_work)->work));
lock(&ctx->uring_lock);
*** DEADLOCK ***
2 locks held by kworker/2:4/2684:
#0: ffff88810004d938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1bc/0x530
#1: ffffc90001c6be70 ((work_completion)(&(&ctx->rsrc_put_work)->work)){+.+.}-{0:0}, at: process_one_work+0x1bc/0x530
stack backtrace:
CPU: 2 PID: 2684 Comm: kworker/2:4 Tainted: G OE 5.14.0-rc3-bluetea-test-00249-gc7d102232649 #5
Hardware name: Acer Aspire ES1-421/OLVIA_BE, BIOS V1.05 07/02/2015
Workqueue: events io_rsrc_put_work
Call Trace:
dump_stack_lvl+0x6a/0x9a
check_noncircular+0xfe/0x110
__lock_acquire+0x119a/0x1e10
lock_acquire+0xc8/0x2f0
? io_rsrc_put_work+0x13d/0x1a0
__mutex_lock+0x86/0x740
? io_rsrc_put_work+0x13d/0x1a0
? io_rsrc_put_work+0x13d/0x1a0
? io_rsrc_put_work+0x13d/0x1a0
? process_one_work+0x1ce/0x530
io_rsrc_put_work+0x13d/0x1a0
process_one_work+0x236/0x530
worker_thread+0x52/0x3b0
? process_one_work+0x530/0x530
kthread+0x135/0x160
? set_kthread_struct+0x40/0x40
ret_from_fork+0x1f/0x30
which is due to holding the ctx->uring_lock when flushing existing
pending work, while the pending work flushing may need to grab the uring
lock if we're using IOPOLL.
Fix this by dropping the uring_lock a bit earlier as part of the flush.
Cc: stable@vger.kernel.org
Link: https://github.com/axboe/liburing/issues/404
Tested-by: Ammar Faizi <ammarfaizi2@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There may be cases like:
A B
spin_lock(wqe->lock)
nr_workers is 0
nr_workers++
spin_unlock(wqe->lock)
spin_lock(wqe->lock)
nr_wokers is 1
nr_workers++
spin_unlock(wqe->lock)
create_io_worker()
acct->worker is 1
create_io_worker()
acct->worker is 1
There should be one worker marked IO_WORKER_F_FIXED, but no one is.
Fix this by introduce a new agrument for create_io_worker() to indicate
if it is the first worker.
Fixes: 3d4e4face9c1 ("io-wq: fix no lock protection of acct->nr_worker")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210808135434.68667-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The former patch to add check between nr_workers and max_workers has a
bug, which will cause unconditionally creating io-workers. That's
because the result of the check doesn't affect the call of
create_io_worker(), fix it by bringing in a boolean value for it.
Fixes: 21698274da5b ("io-wq: fix lack of acct->nr_workers < acct->max_workers judgement")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210808135434.68667-2-haoxu@linux.alibaba.com
[axboe: drop hunk that isn't strictly needed]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Nadav reports running into the below splat on re-enabling softirqs:
WARNING: CPU: 2 PID: 1777 at kernel/softirq.c:364 __local_bh_enable_ip+0xaa/0xe0
Modules linked in:
CPU: 2 PID: 1777 Comm: umem Not tainted 5.13.1+ #161
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/22/2020
RIP: 0010:__local_bh_enable_ip+0xaa/0xe0
Code: a9 00 ff ff 00 74 38 65 ff 0d a2 21 8c 7a e8 ed 1a 20 00 fb 66 0f 1f 44 00 00 5b 41 5c 5d c3 65 8b 05 e6 2d 8c 7a 85 c0 75 9a <0f> 0b eb 96 e8 2d 1f 20 00 eb a5 4c 89 e7 e8 73 4f 0c 00 eb ae 65
RSP: 0018:ffff88812e58fcc8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000201 RCX: dffffc0000000000
RDX: 0000000000000007 RSI: 0000000000000201 RDI: ffffffff8898c5ac
RBP: ffff88812e58fcd8 R08: ffffffff8575dbbf R09: ffffed1028ef14f9
R10: ffff88814778a7c3 R11: ffffed1028ef14f8 R12: ffffffff85c9e9ae
R13: ffff88814778a000 R14: ffff88814778a7b0 R15: ffff8881086db890
FS: 00007fbcfee17700(0000) GS:ffff8881e0300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0402a5008 CR3: 000000011c1ac003 CR4: 00000000003706e0
Call Trace:
_raw_spin_unlock_bh+0x31/0x40
io_rsrc_node_ref_zero+0x13e/0x190
io_dismantle_req+0x215/0x220
io_req_complete_post+0x1b8/0x720
__io_complete_rw.isra.0+0x16b/0x1f0
io_complete_rw+0x10/0x20
where it's clear we end up calling the percpu count release directly
from the completion path, as it's in atomic mode and we drop the last
ref. For file/block IO, this can be from IRQ context already, and the
softirq locking for rsrc isn't enough.
Just make the lock fully IRQ safe, and ensure we correctly safe state
from the release path as we don't know the full context there.
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Tested-by: Nadav Amit <nadav.amit@gmail.com>
Link: https://lore.kernel.org/io-uring/C187C836-E78B-4A31-B24C-D16919ACA093@gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The compiler should be forbidden from any strange optimization for async
writes to user visible data-structures. Without proper protection, the
compiler can cause write-tearing or invent writes that would confuse the
userspace.
However, there are writes to sq_flags which are not protected by
WRITE_ONCE(). Use WRITE_ONCE() for these writes.
This is purely a theoretical issue. Presumably, any compiler is very
unlikely to do such optimizations.
Fixes: 75b28affdd6a ("io_uring: allocate the two rings together")
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Link: https://lore.kernel.org/r/20210808001342.964634-3-namit@vmware.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When using SQPOLL, the submission queue polling thread calls
task_work_run() to run queued work. However, when work is added with
TWA_SIGNAL - as done by io_uring itself - the TIF_NOTIFY_SIGNAL remains
set afterwards and is never cleared.
Consequently, when the submission queue polling thread checks whether
signal_pending(), it may always find a pending signal, if
task_work_add() was ever called before.
The impact of this bug might be different on different kernel versions.
It appears that on 5.14 it would only cause unnecessary calculation and
prevent the polling thread from sleeping. On 5.13, where the bug was
found, it stops the polling thread from finding newly submitted work.
Instead of task_work_run(), use tracehook_notify_signal() that clears
TIF_NOTIFY_SIGNAL. Test for TIF_NOTIFY_SIGNAL in addition to
current->task_works to avoid a race in which task_works is cleared but
the TIF_NOTIFY_SIGNAL is set.
Fixes: 685fe7feedb96 ("io-wq: eliminate the need for a manager thread")
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Link: https://lore.kernel.org/r/20210808001342.964634-2-namit@vmware.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull ceph fixes from Ilya Dryomov:
"A patch to avoid a soft lockup in ceph_check_delayed_caps() from Luis
and a reference handling fix from Jeff that should address some memory
corruption reports in the snaprealm area.
Both marked for stable"
* tag 'ceph-for-5.14-rc6' of git://github.com/ceph/ceph-client:
ceph: take snap_empty_lock atomically with snaprealm refcount change
ceph: reduce contention in ceph_check_delayed_caps()
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There is a race in ceph_put_snap_realm. The change to the nref and the
spinlock acquisition are not done atomically, so you could decrement
nref, and before you take the spinlock, the nref is incremented again.
At that point, you end up putting it on the empty list when it
shouldn't be there. Eventually __cleanup_empty_realms runs and frees
it when it's still in-use.
Fix this by protecting the 1->0 transition with atomic_dec_and_lock,
and just drop the spinlock if we can get the rwsem.
Because these objects can also undergo a 0->1 refcount transition, we
must protect that change as well with the spinlock. Increment locklessly
unless the value is at 0, in which case we take the spinlock, increment
and then take it off the empty list if it did the 0->1 transition.
With these changes, I'm removing the dout() messages from these
functions, as well as in __put_snap_realm. They've always been racy, and
it's better to not print values that may be misleading.
Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/46419
Reported-by: Mark Nelson <mnelson@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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Function ceph_check_delayed_caps() is called from the mdsc->delayed_work
workqueue and it can be kept looping for quite some time if caps keep
being added back to the mdsc->cap_delay_list. This may result in the
watchdog tainting the kernel with the softlockup flag.
This patch breaks this loop if the caps have been recently (i.e. during
the loop execution). Any new caps added to the list will be handled in
the next run.
Also, allow schedule_delayed() callers to explicitly set the delay value
instead of defaulting to 5s, so we can ensure that it runs soon
afterward if it looks like there is more work.
Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/46284
Signed-off-by: Luis Henriques <lhenriques@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ucounts fix from Eric Biederman:
"This fixes the ucount sysctls on big endian architectures.
The counts were expanded to be longs instead of ints, and the sysctl
code was overlooked, so only the low 32bit were being processed. On
litte endian just processing the low 32bits is fine, but on 64bit big
endian processing just the low 32bits results in the high order bits
instead of the low order bits being processed and nothing works
proper.
This change took a little bit to mature as we have the SYSCTL_ZERO,
and SYSCTL_INT_MAX macros that are only usable for sysctls operating
on ints, but unfortunately are not obviously broken. Which resulted in
the versions of this change working on big endian and not on little
endian, because the int SYSCTL_ZERO when extended 64bit wound up being
0x100000000. So we only allowed values greater than 0x100000000 and
less than 0faff. Which unfortunately broken everything that tried to
set the sysctls. (First reported with the windows subsystem for
linux).
I have tested this on x86_64 64bit after first reproducing the
problems with the earlier version of this change, and then verifying
the problems do not exist when we use appropriate long min and max
values for extra1 and extra2"
* 'for-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ucounts: add missing data type changes
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commit f9c82a4ea89c3 ("Increase size of ucounts to atomic_long_t")
changed the data type of ucounts/ucounts_max to long, but missed to
adjust a few other places. This is noticeable on big endian platforms
from user space because the /proc/sys/user/max_*_names files all
contain 0.
v4 - Made the min and max constants long so the sysctl values
are actually settable on little endian machines.
-- EWB
Fixes: f9c82a4ea89c ("Increase size of ucounts to atomic_long_t")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Acked-by: Alexey Gladkov <legion@kernel.org>
v1: https://lkml.kernel.org/r/20210721115800.910778-1-svens@linux.ibm.com
v2: https://lkml.kernel.org/r/20210721125233.1041429-1-svens@linux.ibm.com
v3: https://lkml.kernel.org/r/20210730062854.3601635-1-svens@linux.ibm.com
Link: https://lkml.kernel.org/r/8735rijqlv.fsf_-_@disp2133
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs fixes from Miklos Szeredi:
"Fix several bugs in overlayfs"
* tag 'ovl-fixes-5.14-rc6-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: prevent private clone if bind mount is not allowed
ovl: fix uninitialized pointer read in ovl_lookup_real_one()
ovl: fix deadlock in splice write
ovl: skip stale entries in merge dir cache iteration
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Add the following checks from __do_loopback() to clone_private_mount() as
well:
- verify that the mount is in the current namespace
- verify that there are no locked children
Reported-by: Alois Wohlschlager <alois1@gmx-topmail.de>
Fixes: c771d683a62e ("vfs: introduce clone_private_mount()")
Cc: <stable@vger.kernel.org> # v3.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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One error path can result in release_dentry_name_snapshot() being called
before "name" was initialized by take_dentry_name_snapshot().
Fix by moving the release_dentry_name_snapshot() to immediately after the
only use.
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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There's possibility of an ABBA deadlock in case of a splice write to an
overlayfs file and a concurrent splice write to a corresponding real file.
The call chain for splice to an overlay file:
-> do_splice [takes sb_writers on overlay file]
-> do_splice_from
-> iter_file_splice_write [takes pipe->mutex]
-> vfs_iter_write
...
-> ovl_write_iter [takes sb_writers on real file]
And the call chain for splice to a real file:
-> do_splice [takes sb_writers on real file]
-> do_splice_from
-> iter_file_splice_write [takes pipe->mutex]
Syzbot successfully bisected this to commit 82a763e61e2b ("ovl: simplify
file splice").
Fix by reverting the write part of the above commit and by adding missing
bits from ovl_write_iter() into ovl_splice_write().
Fixes: 82a763e61e2b ("ovl: simplify file splice")
Reported-and-tested-by: syzbot+579885d1a9a833336209@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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On the first getdents call, ovl_iterate() populates the readdir cache
with a list of entries, but for upper entries with origin lower inode,
p->ino remains zero.
Following getdents calls traverse the readdir cache list and call
ovl_cache_update_ino() for entries with zero p->ino to lookup the entry
in the overlay and return d_ino that is consistent with st_ino.
If the upper file was unlinked between the first getdents call and the
getdents call that lists the file entry, ovl_cache_update_ino() will not
find the entry and fall back to setting d_ino to the upper real st_ino,
which is inconsistent with how this object was presented to users.
Instead of listing a stale entry with inconsistent d_ino, simply skip
the stale entry, which is better for users.
xfstest overlay/077 is failing without this patch.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/fstests/CAOQ4uxgR_cLnC_vdU5=seP3fwqVkuZM_-WfD6maFTMbMYq=a9w@mail.gmail.com/
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Pull io_uring from Jens Axboe:
"A few io-wq related fixes:
- Fix potential nr_worker race and missing max_workers check from one
path (Hao)
- Fix race between worker exiting and new work queue (me)"
* tag 'io_uring-5.14-2021-08-07' of git://git.kernel.dk/linux-block:
io-wq: fix lack of acct->nr_workers < acct->max_workers judgement
io-wq: fix no lock protection of acct->nr_worker
io-wq: fix race between worker exiting and activating free worker
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There should be this judgement before we create an io-worker
Fixes: 685fe7feedb9 ("io-wq: eliminate the need for a manager thread")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There is an acct->nr_worker visit without lock protection. Think about
the case: two callers call io_wqe_wake_worker(), one is the original
context and the other one is an io-worker(by calling
io_wqe_enqueue(wqe, linked)), on two cpus paralelly, this may cause
nr_worker to be larger than max_worker.
Let's fix it by adding lock for it, and let's do nr_workers++ before
create_io_worker. There may be a edge cause that the first caller fails
to create an io-worker, but the second caller doesn't know it and then
quit creating io-worker as well:
say nr_worker = max_worker - 1
cpu 0 cpu 1
io_wqe_wake_worker() io_wqe_wake_worker()
nr_worker < max_worker
nr_worker++
create_io_worker() nr_worker == max_worker
failed return
return
But the chance of this case is very slim.
Fixes: 685fe7feedb9 ("io-wq: eliminate the need for a manager thread")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
[axboe: fix unconditional create_io_worker() call]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Nadav correctly reports that we have a race between a worker exiting,
and new work being queued. This can lead to work being queued behind
an existing worker that could be sleeping on an event before it can
run to completion, and hence introducing potential big latency gaps
if we hit this race condition:
cpu0 cpu1
---- ----
io_wqe_worker()
schedule_timeout()
// timed out
io_wqe_enqueue()
io_wqe_wake_worker()
// work_flags & IO_WQ_WORK_CONCURRENT
io_wqe_activate_free_worker()
io_worker_exit()
Fix this by having the exiting worker go through the normal decrement
of a running worker, which will spawn a new one if needed.
The free worker activation is modified to only return success if we
were able to find a sleeping worker - if not, we keep looking through
the list. If we fail, we create a new worker as per usual.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/io-uring/BFF746C0-FEDE-4646-A253-3021C57C26C9@gmail.com/
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Tested-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"A regression fix, bug fix, and a comment cleanup for ext4"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix potential htree corruption when growing large_dir directories
ext4: remove conflicting comment from __ext4_forget
ext4: fix potential uninitialized access to retval in kmmpd
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Commit b5776e7524af ("ext4: fix potential htree index checksum
corruption) removed a required restart when multiple levels of index
nodes need to be split. Fix this to avoid directory htree corruptions
when using the large_dir feature.
Cc: stable@kernel.org # v5.11
Cc: Благодаренко Артём <artem.blagodarenko@gmail.com>
Fixes: b5776e7524af ("ext4: fix potential htree index checksum corruption)
Reported-by: Denis <denis@voxelsoft.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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We do a bforget and return for no journal case, so let's remove this
conflict comment.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
Link: https://lore.kernel.org/r/20210714055940.1553705-1-guoqing.jiang@linux.dev
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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if (!ext4_has_feature_mmp(sb)) then retval can be unitialized before
we jump to the wait_to_exit label.
Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20210713022728.2533770-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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This program always prints 4096 and hangs before the patch, and always
prints 8192 and exits successfully after:
int main()
{
int pipefd[2];
for (int i = 0; i < 1025; i++)
if (pipe(pipefd) == -1)
return 1;
size_t bufsz = fcntl(pipefd[1], F_GETPIPE_SZ);
printf("%zd\n", bufsz);
char *buf = calloc(bufsz, 1);
write(pipefd[1], buf, bufsz);
read(pipefd[0], buf, bufsz-1);
write(pipefd[1], buf, 1);
}
Note that you may need to increase your RLIMIT_NOFILE before running the
program.
Fixes: 759c01142a ("pipe: limit the per-user amount of pages allocated in pipes")
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/lkml/1628086770.5rn8p04n6j.none@localhost/
Link: https://lore.kernel.org/lkml/1628127094.lxxn016tj7.none@localhost/
Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull xfs fixes from Darrick Wong:
"This contains a bunch of bug fixes in XFS.
Dave and I have been busy the last couple of weeks to find and fix as
many log recovery bugs as we can find; here are the results so far. Go
fstests -g recoveryloop! ;)
- Fix a number of coordination bugs relating to cache flushes for
metadata writeback, cache flushes for multi-buffer log writes, and
FUA writes for single-buffer log writes
- Fix a bug with incorrect replay of attr3 blocks
- Fix unnecessary stalls when flushing logs to disk
- Fix spoofing problems when recovering realtime bitmap blocks"
* tag 'xfs-5.14-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: prevent spoofing of rtbitmap blocks when recovering buffers
xfs: limit iclog tail updates
xfs: need to see iclog flags in tracing
xfs: Enforce attr3 buffer recovery order
xfs: logging the on disk inode LSN can make it go backwards
xfs: avoid unnecessary waits in xfs_log_force_lsn()
xfs: log forces imply data device cache flushes
xfs: factor out forced iclog flushes
xfs: fix ordering violation between cache flushes and tail updates
xfs: fold __xlog_state_release_iclog into xlog_state_release_iclog
xfs: external logs need to flush data device
xfs: flush data dev on external log write
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While reviewing the buffer item recovery code, the thought occurred to
me: in V5 filesystems we use log sequence number (LSN) tracking to avoid
replaying older metadata updates against newer log items. However, we
use the magic number of the ondisk buffer to find the LSN of the ondisk
metadata, which means that if an attacker can control the layout of the
realtime device precisely enough that the start of an rt bitmap block
matches the magic and UUID of some other kind of block, they can control
the purported LSN of that spoofed block and thereby break log replay.
Since realtime bitmap and summary blocks don't have headers at all, we
have no way to tell if a block really should be replayed. The best we
can do is replay unconditionally and hope for the best.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
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From the department of "generic/482 keeps on giving", we bring you
another tail update race condition:
iclog:
S1 C1
+-----------------------+-----------------------+
S2 EOIC
Two checkpoints in a single iclog. One is complete, the other just
contains the start record and overruns into a new iclog.
Timeline:
Before S1: Cache flush, log tail = X
At S1: Metadata stable, write start record and checkpoint
At C1: Write commit record, set NEED_FUA
Single iclog checkpoint, so no need for NEED_FLUSH
Log tail still = X, so no need for NEED_FLUSH
After C1,
Before S2: Cache flush, log tail = X
At S2: Metadata stable, write start record and checkpoint
After S2: Log tail moves to X+1
At EOIC: End of iclog, more journal data to write
Releases iclog
Not a commit iclog, so no need for NEED_FLUSH
Writes log tail X+1 into iclog.
At this point, the iclog has tail X+1 and NEED_FUA set. There has
been no cache flush for the metadata between X and X+1, and the
iclog writes the new tail permanently to the log. THis is sufficient
to violate on disk metadata/journal ordering.
We have two options here. The first is to detect this case in some
manner and ensure that the partial checkpoint write sets NEED_FLUSH
when the iclog is already marked NEED_FUA and the log tail changes.
This seems somewhat fragile and quite complex to get right, and it
doesn't actually make it obvious what underlying problem it is
actually addressing from reading the code.
The second option seems much cleaner to me, because it is derived
directly from the requirements of the C1 commit record in the iclog.
That is, when we write this commit record to the iclog, we've
guaranteed that the metadata/data ordering is correct for tail
update purposes. Hence if we only write the log tail into the iclog
for the *first* commit record rather than the log tail at the last
release, we guarantee that the log tail does not move past where the
the first commit record in the log expects it to be.
IOWs, taking the first option means that replay of C1 becomes
dependent on future operations doing the right thing, not just the
C1 checkpoint itself doing the right thing. This makes log recovery
almost impossible to reason about because now we have to take into
account what might or might not have happened in the future when
looking at checkpoints in the log rather than just having to
reconstruct the past...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Because I cannot tell if the NEED_FLUSH flag is being set correctly
by the log force and CIL push machinery without it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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From the department of "WTAF? How did we miss that!?"...
When we are recovering a buffer, the first thing we do is check the
buffer magic number and extract the LSN from the buffer. If the LSN
is older than the current LSN, we replay the modification to it. If
the metadata on disk is newer than the transaction in the log, we
skip it. This is a fundamental v5 filesystem metadata recovery
behaviour.
generic/482 failed with an attribute writeback failure during log
recovery. The write verifier caught the corruption before it got
written to disk, and the attr buffer dump looked like:
XFS (dm-3): Metadata corruption detected at xfs_attr3_leaf_verify+0x275/0x2e0, xfs_attr3_leaf block 0x19be8
XFS (dm-3): Unmount and run xfs_repair
XFS (dm-3): First 128 bytes of corrupted metadata buffer:
00000000: 00 00 00 00 00 00 00 00 3b ee 00 00 4d 2a 01 e1 ........;...M*..
00000010: 00 00 00 00 00 01 9b e8 00 00 00 01 00 00 05 38 ...............8
^^^^^^^^^^^^^^^^^^^^^^^
00000020: df 39 5e 51 58 ac 44 b6 8d c5 e7 10 44 09 bc 17 .9^QX.D.....D...
00000030: 00 00 00 00 00 02 00 83 00 03 00 cc 0f 24 01 00 .............$..
00000040: 00 68 0e bc 0f c8 00 10 00 00 00 00 00 00 00 00 .h..............
00000050: 00 00 3c 31 0f 24 01 00 00 00 3c 32 0f 88 01 00 ..<1.$....<2....
00000060: 00 00 3c 33 0f d8 01 00 00 00 00 00 00 00 00 00 ..<3............
00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
.....
The highlighted bytes are the LSN that was replayed into the
buffer: 0x100000538. This is cycle 1, block 0x538. Prior to replay,
that block on disk looks like this:
$ sudo xfs_db -c "fsb 0x417d" -c "type attr3" -c p /dev/mapper/thin-vol
hdr.info.hdr.forw = 0
hdr.info.hdr.back = 0
hdr.info.hdr.magic = 0x3bee
hdr.info.crc = 0xb5af0bc6 (correct)
hdr.info.bno = 105448
hdr.info.lsn = 0x100000900
^^^^^^^^^^^
hdr.info.uuid = df395e51-58ac-44b6-8dc5-e7104409bc17
hdr.info.owner = 131203
hdr.count = 2
hdr.usedbytes = 120
hdr.firstused = 3796
hdr.holes = 1
hdr.freemap[0-2] = [base,size]
Note the LSN stamped into the buffer on disk: 1/0x900. The version
on disk is much newer than the log transaction that was being
replayed. That's a bug, and should -never- happen.
So I immediately went to look at xlog_recover_get_buf_lsn() to check
that we handled the LSN correctly. I was wondering if there was a
similar "two commits with the same start LSN skips the second
replay" problem with buffers. I didn't get that far, because I found
a much more basic, rudimentary bug: xlog_recover_get_buf_lsn()
doesn't recognise buffers with XFS_ATTR3_LEAF_MAGIC set in them!!!
IOWs, attr3 leaf buffers fall through the magic number checks
unrecognised, so trigger the "recover immediately" behaviour instead
of undergoing an LSN check. IOWs, we incorrectly replay ATTR3 leaf
buffers and that causes silent on disk corruption of inode attribute
forks and potentially other things....
Git history shows this is *another* zero day bug, this time
introduced in commit 50d5c8d8e938 ("xfs: check LSN ordering for v5
superblocks during recovery") which failed to handle the attr3 leaf
buffers in recovery. And we've failed to handle them ever since...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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When we log an inode, we format the "log inode" core and set an LSN
in that inode core. We do that via xfs_inode_item_format_core(),
which calls:
xfs_inode_to_log_dinode(ip, dic, ip->i_itemp->ili_item.li_lsn);
to format the log inode. It writes the LSN from the inode item into
the log inode, and if recovery decides the inode item needs to be
replayed, it recovers the log inode LSN field and writes it into the
on disk inode LSN field.
Now this might seem like a reasonable thing to do, but it is wrong
on multiple levels. Firstly, if the item is not yet in the AIL,
item->li_lsn is zero. i.e. the first time the inode it is logged and
formatted, the LSN we write into the log inode will be zero. If we
only log it once, recovery will run and can write this zero LSN into
the inode.
This means that the next time the inode is logged and log recovery
runs, it will *always* replay changes to the inode regardless of
whether the inode is newer on disk than the version in the log and
that violates the entire purpose of recording the LSN in the inode
at writeback time (i.e. to stop it going backwards in time on disk
during recovery).
Secondly, if we commit the CIL to the journal so the inode item
moves to the AIL, and then relog the inode, the LSN that gets
stamped into the log inode will be the LSN of the inode's current
location in the AIL, not it's age on disk. And it's not the LSN that
will be associated with the current change. That means when log
recovery replays this inode item, the LSN that ends up on disk is
the LSN for the previous changes in the log, not the current
changes being replayed. IOWs, after recovery the LSN on disk is not
in sync with the LSN of the modifications that were replayed into
the inode. This, again, violates the recovery ordering semantics
that on-disk writeback LSNs provide.
Hence the inode LSN in the log dinode is -always- invalid.
Thirdly, recovery actually has the LSN of the log transaction it is
replaying right at hand - it uses it to determine if it should
replay the inode by comparing it to the on-disk inode's LSN. But it
doesn't use that LSN to stamp the LSN into the inode which will be
written back when the transaction is fully replayed. It uses the one
in the log dinode, which we know is always going to be incorrect.
Looking back at the change history, the inode logging was broken by
commit 93f958f9c41f ("xfs: cull unnecessary icdinode fields") way
back in 2016 by a stupid idiot who thought he knew how this code
worked. i.e. me. That commit replaced an in memory di_lsn field that
was updated only at inode writeback time from the inode item.li_lsn
value - and hence always contained the same LSN that appeared in the
on-disk inode - with a read of the inode item LSN at inode format
time. CLearly these are not the same thing.
Before 93f958f9c41f, the log recovery behaviour was irrelevant,
because the LSN in the log inode always matched the on-disk LSN at
the time the inode was logged, hence recovery of the transaction
would never make the on-disk LSN in the inode go backwards or get
out of sync.
A symptom of the problem is this, caught from a failure of
generic/482. Before log recovery, the inode has been allocated but
never used:
xfs_db> inode 393388
xfs_db> p
core.magic = 0x494e
core.mode = 0
....
v3.crc = 0x99126961 (correct)
v3.change_count = 0
v3.lsn = 0
v3.flags2 = 0
v3.cowextsize = 0
v3.crtime.sec = Thu Jan 1 10:00:00 1970
v3.crtime.nsec = 0
After log recovery:
xfs_db> p
core.magic = 0x494e
core.mode = 020444
....
v3.crc = 0x23e68f23 (correct)
v3.change_count = 2
v3.lsn = 0
v3.flags2 = 0
v3.cowextsize = 0
v3.crtime.sec = Thu Jul 22 17:03:03 2021
v3.crtime.nsec = 751000000
...
You can see that the LSN of the on-disk inode is 0, even though it
clearly has been written to disk. I point out this inode, because
the generic/482 failure occurred because several adjacent inodes in
this specific inode cluster were not replayed correctly and still
appeared to be zero on disk when all the other metadata (inobt,
finobt, directories, etc) indicated they should be allocated and
written back.
The fix for this is two-fold. The first is that we need to either
revert the LSN changes in 93f958f9c41f or stop logging the inode LSN
altogether. If we do the former, log recovery does not need to
change but we add 8 bytes of memory per inode to store what is
largely a write-only inode field. If we do the latter, log recovery
needs to stamp the on-disk inode in the same manner that inode
writeback does.
I prefer the latter, because we shouldn't really be trying to log
and replay changes to the on disk LSN as the on-disk value is the
canonical source of the on-disk version of the inode. It also
matches the way we recover buffer items - we create a buf_log_item
that carries the current recovery transaction LSN that gets stamped
into the buffer by the write verifier when it gets written back
when the transaction is fully recovered.
However, this might break log recovery on older kernels even more,
so I'm going to simply ignore the logged value in recovery and stamp
the on-disk inode with the LSN of the transaction being recovered
that will trigger writeback on transaction recovery completion. This
will ensure that the on-disk inode LSN always reflects the LSN of
the last change that was written to disk, regardless of whether it
comes from log recovery or runtime writeback.
Fixes: 93f958f9c41f ("xfs: cull unnecessary icdinode fields")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Before waiting on a iclog in xfs_log_force_lsn(), we don't check to
see if the iclog has already been completed and the contents on
stable storage. We check for completed iclogs in xfs_log_force(), so
we should do the same thing for xfs_log_force_lsn().
This fixed some random up-to-30s pauses seen in unmounting
filesystems in some tests. A log force ends up waiting on completed
iclog, and that doesn't then get flushed (and hence the log force
get completed) until the background log worker issues a log force
that flushes the iclog in question. Then the unmount unblocks and
continues.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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After fixing the tail_lsn vs cache flush race, generic/482 continued
to fail in a similar way where cache flushes were missing before
iclog FUA writes. Tracing of iclog state changes during the fsstress
workload portion of the test (via xlog_iclog* events) indicated that
iclog writes were coming from two sources - CIL pushes and log
forces (due to fsync/O_SYNC operations). All of the cases where a
recovery problem was triggered indicated that the log force was the
source of the iclog write that was not preceeded by a cache flush.
This was an oversight in the modifications made in commit
eef983ffeae7 ("xfs: journal IO cache flush reductions"). Log forces
for fsync imply a data device cache flush has been issued if an
iclog was flushed to disk and is indicated to the caller via the
log_flushed parameter so they can elide the device cache flush if
the journal issued one.
The change in eef983ffeae7 results in iclogs only issuing a cache
flush if XLOG_ICL_NEED_FLUSH is set on the iclog, but this was not
added to the iclogs that the log force code flushes to disk. Hence
log forces are no longer guaranteeing that a cache flush is issued,
hence opening up a potential on-disk ordering failure.
Log forces should also set XLOG_ICL_NEED_FUA as well to ensure that
the actual iclogs it forces to the journal are also on stable
storage before it returns to the caller.
This patch introduces the xlog_force_iclog() helper function to
encapsulate the process of taking a reference to an iclog, switching
its state if WANT_SYNC and flushing it to stable storage correctly.
Both xfs_log_force() and xfs_log_force_lsn() are converted to use
it, as is xlog_unmount_write() which has an elaborate method of
doing exactly the same "write this iclog to stable storage"
operation.
Further, if the log force code needs to wait on a iclog in the
WANT_SYNC state, it needs to ensure that iclog also results in a
cache flush being issued. This covers the case where the iclog
contains the commit record of the CIL flush that the log force
triggered, but it hasn't been written yet because there is still an
active reference to the iclog.
Note: this whole cache flush whack-a-mole patch is a result of log
forces still being iclog state centric rather than being CIL
sequence centric. Most of this nasty code will go away in future
when log forces are converted to wait on CIL sequence push
completion rather than iclog completion. With the CIL push algorithm
guaranteeing that the CIL checkpoint is fully on stable storage when
it completes, we no longer need to iterate iclogs and push them to
ensure a CIL sequence push has completed and so all this nasty iclog
iteration and flushing code will go away.
Fixes: eef983ffeae7 ("xfs: journal IO cache flush reductions")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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We force iclogs in several places - we need them all to have the
same cache flush semantics, so start by factoring out the iclog
force into a common helper.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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There is a race between the new CIL async data device metadata IO
completion cache flush and the log tail in the iclog the flush
covers being updated. This can be seen by repeating generic/482 in a
loop and eventually log recovery fails with a failures such as this:
XFS (dm-3): Starting recovery (logdev: internal)
XFS (dm-3): bad inode magic/vsn daddr 228352 #0 (magic=0)
XFS (dm-3): Metadata corruption detected at xfs_inode_buf_verify+0x180/0x190, xfs_inode block 0x37c00 xfs_inode_buf_verify
XFS (dm-3): Unmount and run xfs_repair
XFS (dm-3): First 128 bytes of corrupted metadata buffer:
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
XFS (dm-3): metadata I/O error in "xlog_recover_items_pass2+0x55/0xc0" at daddr 0x37c00 len 32 error 117
Analysis of the logwrite replay shows that there were no writes to
the data device between the FUA @ write 124 and the FUA at write @
125, but log recovery @ 125 failed. The difference was the one log
write @ 125 moved the tail of the log forwards from (1,8) to (1,32)
and so the inode create intent in (1,8) was not replayed and so the
inode cluster was zero on disk when replay of the first inode item
in (1,32) was attempted.
What this meant was that the journal write that occurred at @ 125
did not ensure that metadata completed before the iclog was written
was correctly on stable storage. The tail of the log moved forward,
so IO must have been completed between the two iclog writes. This
means that there is a race condition between the unconditional async
cache flush in the CIL push work and the tail LSN that is written to
the iclog. This happens like so:
CIL push work AIL push work
------------- -------------
Add to committing list
start async data dev cache flush
.....
<flush completes>
<all writes to old tail lsn are stable>
xlog_write
.... push inode create buffer
<start IO>
.....
xlog_write(commit record)
.... <IO completes>
log tail moves
xlog_assign_tail_lsn()
start_lsn == commit_lsn
<no iclog preflush!>
xlog_state_release_iclog
__xlog_state_release_iclog()
<writes *new* tail_lsn into iclog>
xlog_sync()
....
submit_bio()
<tail in log moves forward without flushing written metadata>
Essentially, this can only occur if the commit iclog is issued
without a cache flush. If the iclog bio is submitted with
REQ_PREFLUSH, then it will guarantee that all the completed IO is
one stable storage before the iclog bio with the new tail LSN in it
is written to the log.
IOWs, the tail lsn that is written to the iclog needs to be sampled
*before* we issue the cache flush that guarantees all IO up to that
LSN has been completed.
To fix this without giving up the performance advantage of the
flush/FUA optimisations (e.g. g/482 runtime halves with 5.14-rc1
compared to 5.13), we need to ensure that we always issue a cache
flush if the tail LSN changes between the initial async flush and
the commit record being written. THis requires sampling the tail_lsn
before we start the flush, and then passing the sampled tail LSN to
xlog_state_release_iclog() so it can determine if the the tail LSN
has changed while writing the checkpoint. If the tail LSN has
changed, then it needs to set the NEED_FLUSH flag on the iclog and
we'll issue another cache flush before writing the iclog.
Fixes: eef983ffeae7 ("xfs: journal IO cache flush reductions")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Fold __xlog_state_release_iclog into its only caller to prepare
make an upcoming fix easier.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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The recent journal flush/FUA changes replaced the flushing of the
data device on every iclog write with an up-front async data device
cache flush. Unfortunately, the assumption of which this was based
on has been proven incorrect by the flush vs log tail update
ordering issue. As the fix for that issue uses the
XLOG_ICL_NEED_FLUSH flag to indicate that data device needs a cache
flush, we now need to (once again) ensure that an iclog write to
external logs that need a cache flush to be issued actually issue a
cache flush to the data device as well as the log device.
Fixes: eef983ffeae7 ("xfs: journal IO cache flush reductions")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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