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Wengang Wang reports that a customer's system was running a number of
truncate operations on a filesystem with a very small log. Contention
on the reserve heads lead to other threads stalling on smaller updates
(e.g. mtime updates) long enough to result in the node being rebooted
on account of the lack of responsivenes. The node failed to recover
because log recovery of an EFI became stuck waiting for a grant of
reserve space. From Wengang's report:
"For the file deletion, log bytes are reserved basing on
xfs_mount->tr_itruncate which is:
tr_logres = 175488,
tr_logcount = 2,
tr_logflags = XFS_TRANS_PERM_LOG_RES,
"You see it's a permanent log reservation with two log operations (two
transactions in rolling mode). After calculation (xlog_calc_unit_res()
adds space for various log headers), the final log space needed per
transaction changes from 175488 to 180208 bytes. So the total log
space needed is 360416 bytes (180208 * 2). [That quantity] of log space
(360416 bytes) needs to be reserved for both run time inode removing
(xfs_inactive_truncate()) and EFI recover (xfs_efi_item_recover())."
In other words, runtime pre-reserves 360K of space in anticipation of
running a chain of two transactions in which each transaction gets a
180K reservation.
Now that we've allocated the transaction, we delete the bmap mapping,
log an EFI to free the space, and roll the transaction as part of
finishing the deferops chain. Rolling creates a new xfs_trans which
shares its ticket with the old transaction. Next, xfs_trans_roll calls
__xfs_trans_commit with regrant == true, which calls xlog_cil_commit
with the same regrant parameter.
xlog_cil_commit calls xfs_log_ticket_regrant, which decrements t_cnt and
subtracts t_curr_res from the reservation and write heads.
If the filesystem is fresh and the first transaction only used (say)
20K, then t_curr_res will be 160K, and we give that much reservation
back to the reservation head. Or if the file is really fragmented and
the first transaction actually uses 170K, then t_curr_res will be 10K,
and that's what we give back to the reservation.
Having done that, we're now headed into the second transaction with an
EFI and 180K of reservation. Other threads apparently consumed all the
reservation for smaller transactions, such as timestamp updates.
Now let's say the first transaction gets written to disk and we crash
without ever completing the second transaction. Now we remount the fs,
log recovery finds the unfinished EFI, and calls xfs_efi_recover to
finish the EFI. However, xfs_efi_recover starts a new tr_itruncate
tranasction, which asks for 360K log reservation. This is a lot more
than the 180K that we had reserved at the time of the crash. If the
first EFI to be recovered is also pinning the tail of the log, we will
be unable to free any space in the log, and recovery livelocks.
Wengang confirmed this:
"Now we have the second transaction which has 180208 log bytes reserved
too. The second transaction is supposed to process intents including
extent freeing. With my hacking patch, I blocked the extent freeing 5
hours. So in that 5 hours, 180208 (NOT 360416) log bytes are reserved.
"With my test case, other transactions (update timestamps) then happen.
As my hacking patch pins the journal tail, those timestamp-updating
transactions finally use up (almost) all the left available log space
(in memory in on disk). And finally the on disk (and in memory)
available log space goes down near to 180208 bytes. Those 180208 bytes
are reserved by [the] second (extent-free) transaction [in the chain]."
Wengang and I noticed that EFI recovery starts a transaction, completes
one step of the chain, and commits the transaction without completing
any other steps of the chain. Those subsequent steps are completed by
xlog_finish_defer_ops, which allocates yet another transaction to
finish the rest of the chain. That transaction gets the same tr_logres
as the head transaction, but with tr_logcount = 1 to force regranting
with every roll to avoid livelocks.
In other words, we already figured this out in commit 929b92f64048d
("xfs: xfs_defer_capture should absorb remaining transaction
reservation"), but should have applied that logic to each intent item's
recovery function. For Wengang's case, the xfs_trans_alloc call in the
EFI recovery function should only be asking for a single transaction's
worth of log reservation -- 180K, not 360K.
Quoting Wengang again:
"With log recovery, during EFI recovery, we use tr_itruncate again to
reserve two transactions that needs 360416 log bytes. Reserving 360416
bytes fails [stalls] because we now only have about 180208 available.
"Actually during the EFI recover, we only need one transaction to free
the extents just like the 2nd transaction at RUNTIME. So it only needs
to reserve 180208 rather than 360416 bytes. We have (a bit) more than
180208 available log bytes on disk, so [if we decrease the reservation
to 180K] the reservation goes and the recovery [finishes]. That is to
say: we can fix the log recover part to fix the issue. We can introduce
a new xfs_trans_res xfs_mount->tr_ext_free
{
tr_logres = 175488,
tr_logcount = 0,
tr_logflags = 0,
}
"and use tr_ext_free instead of tr_itruncate in EFI recover."
However, I don't think it quite makes sense to create an entirely new
transaction reservation type to handle single-stepping during log
recovery. Instead, we should copy the transaction reservation
information in the xfs_mount, change tr_logcount to 1, and pass that
into xfs_trans_alloc. We know this won't risk changing the min log size
computation since we always ask for a fraction of the reservation for
all known transaction types.
This looks like it's been lurking in the codebase since commit
3d3c8b5222b92, which changed the xfs_trans_reserve call in
xlog_recover_process_efi to use the tr_logcount in tr_itruncate.
That changed the EFI recovery transaction from making a
non-XFS_TRANS_PERM_LOG_RES request for one transaction's worth of log
space to a XFS_TRANS_PERM_LOG_RES request for two transactions worth.
Fixes: 3d3c8b5222b92 ("xfs: refactor xfs_trans_reserve() interface")
Complements: 929b92f64048d ("xfs: xfs_defer_capture should absorb remaining transaction reservation")
Suggested-by: Wengang Wang <wen.gang.wang@oracle.com>
Cc: Srikanth C S <srikanth.c.s@oracle.com>
[djwong: apply the same transformation to all log intent recovery]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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Log recovery has always run on read only mounts, even where the primary
superblock advertises unknown rocompat bits. Due to a misunderstanding
between Eric and Darrick back in 2018, we accidentally changed the
superblock write verifier to shutdown the fs over that exact scenario.
As a result, the log cleaning that occurs at the end of the mounting
process fails if there are unknown rocompat bits set.
As we now allow writing of the superblock if there are unknown rocompat
bits set on a RO mount, we no longer want to turn off RO state to allow
log recovery to succeed on a RO mount. Hence we also remove all the
(now unnecessary) RO state toggling from the log recovery path.
Fixes: 9e037cb7972f ("xfs: check for unknown v5 feature bits in superblock write verifier"
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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In the next patch, we're going to prohibit log recovery if the primary
superblock contains an unrecognized rocompat feature bit even on
readonly mounts. This requires removing all the code in the log
mounting process that temporarily disables the readonly state.
Unfortunately, inode inactivation disables itself on readonly mounts.
Clearing the iunlinked lists after log recovery needs inactivation to
run to free the unreferenced inodes, which (AFAICT) is the only reason
why log mounting plays games with the readonly state in the first place.
Therefore, change the inactivation predicates to allow inactivation
during log recovery of a readonly mount.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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There are no users of the cpu hotplug hooks in xfs now, so remove it.
This reverts f1653c2e2831e ("xfs: introduce CPU hotplug
infrastructure").
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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Revert commit 0ed17f01c8540 ("xfs: introduce all-mounts list for cpu
hotplug notifications") because the cpu hotplug hooks are now pointless,
so we don't need this list anymore.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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Directly track which CPUs have contributed to the inodegc percpu lists
instead of trusting the cpu online mask. This eliminates a theoretical
problem where the inodegc flush functions might fail to flush a CPU's
inodes if that CPU happened to be dying at exactly the same time. Most
likely nobody's noticed this because the CPU dead hook moves the percpu
inodegc list to another CPU and schedules that worker immediately. But
it's quite possible that this is a subtle race leading to UAF if the
inodegc flush were part of an unmount.
Further benefits: This reduces the overhead of the inodegc flush code
slightly by allowing us to ignore CPUs that have empty lists. Better
yet, it reduces our dependence on the cpu online masks, which have been
the cause of confusion and drama lately.
Fixes: ab23a7768739 ("xfs: per-cpu deferred inode inactivation queues")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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In commit 7c8ade2121200 ("xfs: implement percpu cil space used
calculation"), the XFS committed (log) item list code was converted to
use per-cpu lists and space tracking to reduce cpu contention when
multiple threads are modifying different parts of the filesystem and
hence end up contending on the log structures during transaction commit.
Each CPU tracks its own commit items and space usage, and these do not
have to be merged into the main CIL until either someone wants to push
the CIL items, or we run over a soft threshold and switch to slower (but
more accurate) accounting with atomics.
Unfortunately, the for_each_cpu iteration suffers from the same race
with cpu dying problem that was identified in commit 8b57b11cca88f
("pcpcntrs: fix dying cpu summation race") -- CPUs are removed from
cpu_online_mask before the CPUHP_XFS_DEAD callback gets called. As a
result, both CIL percpu structure aggregation functions fail to collect
the items and accounted space usage at the correct point in time.
If we're lucky, the items that are collected from the online cpus exceed
the space given to those cpus, and the log immediately shuts down in
xlog_cil_insert_items due to the (apparent) log reservation overrun.
This happens periodically with generic/650, which exercises cpu hotplug
vs. the filesystem code:
smpboot: CPU 3 is now offline
XFS (sda3): ctx ticket reservation ran out. Need to up reservation
XFS (sda3): ticket reservation summary:
XFS (sda3): unit res = 9268 bytes
XFS (sda3): current res = -40 bytes
XFS (sda3): original count = 1
XFS (sda3): remaining count = 1
XFS (sda3): Filesystem has been shut down due to log error (0x2).
Applying the same sort of fix from 8b57b11cca88f to the CIL code seems
to make the generic/650 problem go away, but I've been told that tglx
was not happy when he saw:
"...the only thing we actually need to care about is that
percpu_counter_sum() iterates dying CPUs. That's trivial to do, and when
there are no CPUs dying, it has no addition overhead except for a
cpumask_or() operation."
The CPU hotplug code is rather complex and difficult to understand and I
don't want to try to understand the cpu hotplug locking well enough to
use cpu_dying mask. Furthermore, there's a performance improvement that
could be had here. Attach a private cpu mask to the CIL structure so
that we can track exactly which cpus have accessed the percpu data at
all. It doesn't matter if the cpu has since gone offline; log item
aggregation will still find the items. Better yet, we skip cpus that
have not recently logged anything.
Worse yet, Ritesh Harjani and Eric Sandeen both reported today that CPU
hot remove racing with an xfs mount can crash if the cpu_dead notifier
tries to access the log but the mount hasn't yet set up the log.
Link: https://lore.kernel.org/linux-xfs/ZOLzgBOuyWHapOyZ@dread.disaster.area/T/
Link: https://lore.kernel.org/lkml/877cuj1mt1.ffs@tglx/
Link: https://lore.kernel.org/lkml/20230414162755.281993820@linutronix.de/
Link: https://lore.kernel.org/linux-xfs/ZOVkjxWZq0YmjrJu@dread.disaster.area/T/
Cc: tglx@linutronix.de
Cc: peterz@infradead.org
Reported-by: ritesh.list@gmail.com
Reported-by: sandeen@sandeen.net
Fixes: af1c2146a50b ("xfs: introduce per-cpu CIL tracking structure")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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Dave Chinner reported that xfs/273 fails if the AG size happens to be an
exact power of two. I traced this to an agbno integer overflow when the
current GETFSMAP call is a continuation of a previous GETFSMAP call, and
the last record returned was non-shareable space at the end of an AG.
__xfs_getfsmap_datadev sets up a data device query by converting the
incoming fmr_physical into an xfs_fsblock_t and cracking it into an agno
and agbno pair. In the (failing) case of where fmr_blockcount of the
low key is nonzero and the record was for a non-shareable extent, it
will add fmr_blockcount to start_fsb and info->low.rm_startblock.
If the low key was actually the last record for that AG, then this
addition causes info->low.rm_startblock to point beyond EOAG. When the
rmapbt range query starts, it'll return an empty set, and fsmap moves on
to the next AG.
Or so I thought. Remember how we added to start_fsb?
If agsize < 1<<agblklog, start_fsb points to the same AG as the original
fmr_physical from the low key. We run the rmapbt query, which returns
nothing, so getfsmap zeroes info->low and moves on to the next AG.
If agsize == 1<<agblklog, start_fsb now points to the next AG. We run
the rmapbt query on the next AG with the excessively large
rm_startblock. If this next AG is actually the last AG, we'll set
info->high to EOFS (which is now has a lower rm_startblock than
info->low), and the ranged btree query code will return -EINVAL. If
it's not the last AG, we ignore all records for the intermediate AGs.
Oops.
Fix this by decoding start_fsb into agno and agbno only after making
adjustments to start_fsb. This means that info->low.rm_startblock will
always be set to a valid agbno, and we always start the rmapbt iteration
in the correct AG.
While we're at it, fix the predicate for determining if an fsmap record
represents non-shareable space to include file data on pre-reflink
filesystems.
Reported-by: Dave Chinner <david@fromorbit.com>
Fixes: 63ef7a35912dd ("xfs: fix interval filtering in multi-step fsmap queries")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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git://git.samba.org/sfrench/cifs-2.6
Pull smb client fixes from Steve French:
- six smb3 client fixes including ones to allow controlling smb3
directory caching timeout and limits, and one debugging improvement
- one fix for nls Kconfig (don't need to expose NLS_UCS2_UTILS option)
- one minor spnego registry update
* tag '6.6-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
spnego: add missing OID to oid registry
smb3: fix minor typo in SMB2_GLOBAL_CAP_LARGE_MTU
cifs: update internal module version number for cifs.ko
smb3: allow controlling maximum number of cached directories
smb3: add trace point for queryfs (statfs)
nls: Hide new NLS_UCS2_UTILS
smb3: allow controlling length of time directory entries are cached with dir leases
smb: propagate error code of extract_sharename()
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Pull smb server update from Steve French:
"After two years, many fixes and much testing, ksmbd is no longer
experimental"
* tag '6.6-rc-ksmbd' of git://git.samba.org/ksmbd:
ksmbd: remove experimental warning
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There was a minor typo in the define for SMB2_GLOBAL_CAP_LARGE_MTU
0X00000004 instead of 0x00000004
make it consistent
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Recently we moved most cleanup from ntfs_put_super() into
ntfs3_kill_sb() as part of a bigger cleanup. This accidently also moved
dropping inode references stashed in ntfs3's sb->s_fs_info from
@sb->put_super() to @sb->kill_sb(). But generic_shutdown_super()
verifies that there are no busy inodes past sb->put_super(). Fix this
and disentangle dropping inode references from freeing @sb->s_fs_info.
Fixes: a4f64a300a29 ("ntfs3: free the sbi in ->kill_sb") # mainline only
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Mateusz reports that glibc turns 'fstat()' calls into 'fstatat()', and
that seems to have been going on for quite a long time due to glibc
having tried to simplify its stat logic into just one point.
This turns out to cause completely unnecessary overhead, where we then
go off and allocate the kernel side pathname, and actually look up the
empty path. Sure, our path lookup is quite optimized, but it still
causes a fair bit of allocation overhead and a couple of completely
unnecessary rounds of lockref accesses etc.
This is all hopefully getting fixed in user space, and there is a patch
floating around for just having glibc use the native fstat() system
call. But even with the current situation we can at least improve on
things by catching the situation and short-circuiting it.
Note that this is still measurably slower than just a plain 'fstat()',
since just checking that the filename is actually empty is somewhat
expensive due to inevitable user space access overhead from the kernel
(ie verifying pointers, and SMAP on x86). But it's still quite a bit
faster than actually looking up the path for real.
To quote numers from Mateusz:
"Sapphire Rapids, will-it-scale, ops/s
stock fstat 5088199
patched fstat 7625244 (+49%)
real fstat 8540383 (+67% / +12%)"
where that 'stock fstat' is the glibc translation of fstat into
fstatat() with an empty path, the 'patched fstat' is with this short
circuiting of the path lookup, and the 'real fstat' is the actual native
fstat() system call with none of this overhead.
Link: https://lore.kernel.org/lkml/20230903204858.lv7i3kqvw6eamhgz@f/
Reported-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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From 2.44 to 2.45
Signed-off-by: Steve French <stfrench@microsoft.com>
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Allow adjusting the maximum number of cached directories per share
(defaults to 16) via mount parm "max_cached_dirs"
Signed-off-by: Steve French <stfrench@microsoft.com>
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In debugging a recent performance problem with statfs, it would have
been helpful to be able to trace the smb3 query fs info request
more narrowly. Add a trace point "smb3_qfs_done"
Which displays:
stat-68950 [008] ..... 1472.360598: smb3_qfs_done: xid=14 sid=0xaa9765e4 tid=0x95a76f54 unc_name=\\localhost\test rc=0
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Pull ceph updates from Ilya Dryomov:
"Mixed with some fixes and cleanups, this brings in reasonably complete
fscrypt support to CephFS! The list of things which don't work with
encryption should be fairly short, mostly around the edges: fallocate
(not supported well in CephFS to begin with), copy_file_range
(requires re-encryption), non-default striping patterns.
This was a multi-year effort principally by Jeff Layton with
assistance from Xiubo Li, Luís Henriques and others, including several
dependant changes in the MDS, netfs helper library and fscrypt
framework itself"
* tag 'ceph-for-6.6-rc1' of https://github.com/ceph/ceph-client: (53 commits)
ceph: make num_fwd and num_retry to __u32
ceph: make members in struct ceph_mds_request_args_ext a union
rbd: use list_for_each_entry() helper
libceph: do not include crypto/algapi.h
ceph: switch ceph_lookup/atomic_open() to use new fscrypt helper
ceph: fix updating i_truncate_pagecache_size for fscrypt
ceph: wait for OSD requests' callbacks to finish when unmounting
ceph: drop messages from MDS when unmounting
ceph: update documentation regarding snapshot naming limitations
ceph: prevent snapshot creation in encrypted locked directories
ceph: add support for encrypted snapshot names
ceph: invalidate pages when doing direct/sync writes
ceph: plumb in decryption during reads
ceph: add encryption support to writepage and writepages
ceph: add read/modify/write to ceph_sync_write
ceph: align data in pages in ceph_sync_write
ceph: don't use special DIO path for encrypted inodes
ceph: add truncate size handling support for fscrypt
ceph: add object version support for sync read
libceph: allow ceph_osdc_new_request to accept a multi-op read
...
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git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 updates from Andreas Gruenbacher:
- Fix a glock state (non-)transition bug when a dlm request times out
and is canceled, and we have locking requests that can now be granted
immediately
- Various fixes and cleanups in how the logd and quotad daemons are
woken up and terminated
- Fix several bugs in the quota data reference counting and shrinking.
Free quota data objects synchronously in put_super() instead of
letting call_rcu() run wild
- Make sure not to deallocate quota data during a withdraw; rather,
defer quota data deallocation to put_super(). Withdraws can happen in
contexts in which callers on the stack are holding quota data
references
- Many minor quota fixes and cleanups by Bob
- Update the the mailing list address for gfs2 and dlm. (It's the same
list for both and we are moving it to gfs2@lists.linux.dev)
- Various other minor cleanups
* tag 'gfs2-v6.5-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: (51 commits)
MAINTAINERS: Update dlm mailing list
MAINTAINERS: Update gfs2 mailing list
gfs2: change qd_slot_count to qd_slot_ref
gfs2: check for no eligible quota changes
gfs2: Remove useless assignment
gfs2: simplify slot_get
gfs2: Simplify qd2offset
gfs2: introduce qd_bh_get_or_undo
gfs2: Remove quota allocation info from quota file
gfs2: use constant for array size
gfs2: Set qd_sync_gen in do_sync
gfs2: Remove useless err set
gfs2: Small gfs2_quota_lock cleanup
gfs2: move qdsb_put and reduce redundancy
gfs2: improvements to sysfs status
gfs2: Don't try to sync non-changes
gfs2: Simplify function need_sync
gfs2: remove unneeded pg_oflow variable
gfs2: remove unneeded variable done
gfs2: pass sdp to gfs2_write_buf_to_page
...
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
- Revert non-waiting FLUSH due to a regression
- Fix a lookup counter leak in readdirplus
- Add an option to allow shared mmaps in no-cache mode
- Add btime support and statx intrastructure to the protocol
- Invalidate positive/negative dentry on failed create/delete
* tag 'fuse-update-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: conditionally fill kstat in fuse_do_statx()
fuse: invalidate dentry on EEXIST creates or ENOENT deletes
fuse: cache btime
fuse: implement statx
fuse: add ATTR_TIMEOUT macro
fuse: add STATX request
fuse: handle empty request_mask in statx
fuse: write back dirty pages before direct write in direct_io_relax mode
fuse: add a new fuse init flag to relax restrictions in no cache mode
fuse: invalidate page cache pages before direct write
fuse: nlookup missing decrement in fuse_direntplus_link
Revert "fuse: in fuse_flush only wait if someone wants the return code"
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- Stefan Roesch has added ksm statistics to /proc/pid/smaps
- Also a number of singleton patches, mainly cleanups and leftovers
* tag 'mm-stable-2023-09-04-14-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/kmemleak: move up cond_resched() call in page scanning loop
mm: page_alloc: remove stale CMA guard code
MAINTAINERS: add rmap.h to mm entry
rmap: remove anon_vma_link() nommu stub
proc/ksm: add ksm stats to /proc/pid/smaps
mm/hwpoison: rename hwp_walk* to hwpoison_walk*
mm: memory-failure: add PageOffline() check
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Variable qd_slot_count is a reference count, not a count of slots. This
patch renames it to qd_slot_ref to make that more clear.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Before this patch, function gfs2_quota_sync would always allocate a page
full of memory and increment its quota sync generation number. This
happened even when the system was completely idle or if no blocks were
allocated or quota changes made. This patch adds function qd_changed
to determine if any changes have been made that qualify for a
quota sync. If not, it avoids the memory allocation and bumping the
generation number, along with all the additional work it would do.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This assignment is unnecessary because if error was not already 0, it
would have branched to an error label already.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Simplify function slot_get and get rid of the goto that jumps into the
middle of an else branch.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This is a minor cleanup of function qd2offset.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch is an attempt to force some consistency in quota sync
processing. Two functions (qd_fish and gfs2_quota_unlock) called
qd_check_sync, after which they both called bh_get, and if that failed,
they took the same steps to undo the actions of qd_check_sync.
This patch introduces a new function, qd_bh_get_or_undo, which performs
the same steps, reducing code redundancy.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function do_sync called gfs2_qa_get and put for quota allocation data.
But the inode in question is the system master quota file, which is
never subject to quotas. Therefore, a qa structure should be unnecessary
and if anything accesses it, it's probably a bug.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function gfs2_quota_unlock declared an array of 4 qd elements. We have a
constant for that, we should be using it.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Func do_sync was called in two places: gfs2_quota_unlock and
gfs2_quota_sync. In gfs2_quota_sync it updated qd_sync_gen to the latest
superblock sync gen, if do_sync was successful. In gfs2_quota_unlock it
didn't update the value. That can only lead to extra work, for example,
if the value is synced by gfs2_quota_unlock but still has the old value.
This patch moves the setting of qd_sync_gen inside do_sync so we are
guaranteed consistency.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function gfs2_adjust_quota set variable err, then set it again to a
different value. This patch removes the redundant set.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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No need to set error = 0 since it's set further down.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch looks more invasive than it is. It simply moves function
qdsb_put before qd_unlock, then changes qd_unlock to call it rather than
open coding it. Again, this reduces redundancy.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch adds some new fields to the gfs2 status file in sysfs to aid
in debugging.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function need_sync is supposed to determine if a qd element needs to be
synced. If the "change" (qd_change) is zero, it does not need to be
synced because there's literally no change in the value. Before this
patch need_sync returned false if value < 0. That should be <= 0.
This patch changes the check to <=.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch simplifies function need_sync by eliminating a variable in
favor of just returning the appropriate value as soon as we know it.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function gfs2_write_disk_quota checks if its write overflows onto
another page, and if so, does a second write. Before this patch it kept
two variables for this, but only one is needed. This patch simplifies
it by eliminating pg_oflow.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function gfs2_write_buf_to_page uses variable done to exit its loop, but
it's unnecessary if we just code an infinite loop and exit when we need.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch passes the superblock pointer to gfs2_write_buf_to_page so it
becomes more apparent it's dealing with the system quota file.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Like the previous patch, we now pass the superblock pointer to function
gfs2_write_disk_quota. This makes the code more understandable, since it
only operates on the quota inode.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Before this change function gfs2_adjust_quota's first parameter was an
gfs2_inode pointer. But it always pointed to the quota inode. Here we
switch that to pass the superblock pointer, sdp, so it is easier to read
the code and understand that it's only dealing with the quota inode.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Since patch 845802b112ee function gfs2_write_buf_to_page checks if the
target inode is jdata or ordered. This function only operates on the
system quota file, which is always jdata, so the check for jdata is
useless. This patch removes it.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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This patch adds a new mount option quota=quiet which is the same as
quota=on but it suppresses gfs2 quota error messages.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Add the device name to the names of the gfs2_logd and gfs2_quotad kernel
threads to allow for easier identification.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Rename the "gfs_recovery" workqueue to "gfs2_recovery", and
gfs_recovery_wq to gfs2_recovery_wq.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Function gfs2_withdraw() tries to synchronize concurrent callers by
atomically setting the SDF_WITHDRAWN flag in the first caller, setting
the SDF_WITHDRAW_IN_PROG flag to indicate that a withdraw is in
progress, performing the actual withdraw, and clearing the
SDF_WITHDRAW_IN_PROG flag when done. All other callers wait for the
SDF_WITHDRAW_IN_PROG flag to be cleared before returning.
This leaves a small window in which callers can find the SDF_WITHDRAWN
flag set before the SDF_WITHDRAW_IN_PROG flag has been set, causing them
to return prematurely, before the withdraw has been completed.
Fix that by setting the SDF_WITHDRAWN and SDF_WITHDRAW_IN_PROG flags
atomically.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Immediately stop the logd and quotad kernel threads when a filesystem
withdraw is detected: those threads aren't doing anything useful after a
withdraw. (Depends on the extra logd and quotad task struct references
held since commit 7a109f383fa3 ("gfs2: Fix asynchronous thread
destruction").)
In addition, check for kthread_should_stop() in the wait condition in
gfs2_quotad() to stop immediately when kthread_stop() is called.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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In gfs2_quotad(), switch from an open-coded wait loop to
wait_event_interruptible_timeout().
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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The kernel threads are currently stopped and destroyed synchronously by
gfs2_make_fs_ro() and gfs2_put_super(), and asynchronously by
signal_our_withdraw(), with no synchronization, so the synchronous and
asynchronous contexts can race with each other.
First, when creating the kernel threads, take an extra task struct
reference so that the task struct won't go away immediately when they
terminate. This allows those kthreads to terminate immediately when
they're done rather than hanging around as zombies until they are reaped
by kthread_stop(). When kthread_stop() is called on a terminated
kthread, it will return immediately.
Second, in signal_our_withdraw(), once the SDF_JOURNAL_LIVE flag has
been cleared, wake up the logd and quotad wait queues instead of
stopping the logd and quotad kthreads. The kthreads are then expected
to terminate automatically within short time, but if they cannot, they
will not block the withdraw.
For example, if a user process and one of the kthread decide to withdraw
at the same time, only one of them will perform the actual withdraw and
the other will wait for it to be done. If the kthread ends up being the
one to wait, the withdrawing user process won't be able to stop it.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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[ 81.372851][ T5532] CPU: 1 PID: 5532 Comm: syz-executor.0 Not tainted 6.2.0-rc1-syzkaller-dirty #0
[ 81.382080][ T5532] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
[ 81.392343][ T5532] Call Trace:
[ 81.395654][ T5532] <TASK>
[ 81.398603][ T5532] dump_stack_lvl+0x1b1/0x290
[ 81.418421][ T5532] gfs2_assert_warn_i+0x19a/0x2e0
[ 81.423480][ T5532] gfs2_quota_cleanup+0x4c6/0x6b0
[ 81.428611][ T5532] gfs2_make_fs_ro+0x517/0x610
[ 81.457802][ T5532] gfs2_withdraw+0x609/0x1540
[ 81.481452][ T5532] gfs2_inode_refresh+0xb2d/0xf60
[ 81.506658][ T5532] gfs2_instantiate+0x15e/0x220
[ 81.511504][ T5532] gfs2_glock_wait+0x1d9/0x2a0
[ 81.516352][ T5532] do_sync+0x485/0xc80
[ 81.554943][ T5532] gfs2_quota_sync+0x3da/0x8b0
[ 81.559738][ T5532] gfs2_sync_fs+0x49/0xb0
[ 81.564063][ T5532] sync_filesystem+0xe8/0x220
[ 81.568740][ T5532] generic_shutdown_super+0x6b/0x310
[ 81.574112][ T5532] kill_block_super+0x79/0xd0
[ 81.578779][ T5532] deactivate_locked_super+0xa7/0xf0
[ 81.584064][ T5532] cleanup_mnt+0x494/0x520
[ 81.593753][ T5532] task_work_run+0x243/0x300
[ 81.608837][ T5532] exit_to_user_mode_loop+0x124/0x150
[ 81.614232][ T5532] exit_to_user_mode_prepare+0xb2/0x140
[ 81.619820][ T5532] syscall_exit_to_user_mode+0x26/0x60
[ 81.625287][ T5532] do_syscall_64+0x49/0xb0
[ 81.629710][ T5532] entry_SYSCALL_64_after_hwframe+0x63/0xcd
In this backtrace, gfs2_quota_sync() takes quota data references and
then calls do_sync(). Function do_sync() encounters filesystem
corruption and withdraws the filesystem, which (among other things) calls
gfs2_quota_cleanup(). Function gfs2_quota_cleanup() wrongly assumes
that nobody is holding any quota data references anymore, and destroys
all quota data objects. When gfs2_quota_sync() then resumes and
dereferences the quota data objects it is holding, those objects are no
longer there.
Function gfs2_quota_cleanup() deals with resource deallocation and can
easily be delayed until gfs2_put_super() in the case of a filesystem
withdraw. In fact, most of the other work gfs2_make_fs_ro() does is
unnecessary during a withdraw as well, so change signal_our_withdraw()
to skip gfs2_make_fs_ro() and perform the necessary steps directly
instead.
Thanks to Edward Adam Davis <eadavis@sina.com> for the initial patches.
Link: https://lore.kernel.org/all/0000000000002b5e2405f14e860f@google.com
Reported-by: syzbot+3f6a670108ce43356017@syzkaller.appspotmail.com
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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