svc_process_bc(), previously known as bc_svc_process(), was
added in commit 4d6bbb6233 ("nfs41: Backchannel bc_svc_process()")
but there has never been a call site outside of the sunrpc.ko
module.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add a trace point that records SEQ4_STATUS flags returned in an
NFSv4.1 SEQUENCE response. SEQ4_STATUS flags report backchannel
issues and changes to lease state to clients. Knowing what the
server is reporting to clients is useful for debugging both
configuration and operational issues in real time.
For example, upcoming patches will enable server administrators to
revoke parts of a client's lease; that revocation is indicated to
the client when a subsequent SEQUENCE operation has one or more
SEQ4_STATUS flags that are set.
Sample trace records:
nfsd-927 [006] 615.581821: nfsd_seq4_status: xid=0x095ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
nfsd-927 [006] 615.588043: nfsd_seq4_status: xid=0x0a5ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
nfsd-928 [003] 615.588448: nfsd_seq4_status: xid=0x0b5ded07 sessionid=65a032c3:b7845faf:00000001:00000000 status_flags=BACKCHANNEL_FAULT
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
NFSv4.1 clients assume that if they disconnect, that will force the
server to resend pending callback operations once a fresh connection
has been established.
Turns out NFSD has not been resending after reconnect.
Fixes: 7ba6cad6c8 ("nfsd: New helper nfsd4_cb_sequence_done() for processing more cb errors")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
As part of managing a client disconnect, NFSD closes down and
replaces the backchannel rpc_clnt.
If a callback operation is pending when the backchannel rpc_clnt is
shut down, currently nfsd4_run_cb_work() just discards that
callback. But there are multiple cases to deal with here:
o The client's lease is getting destroyed. Throw the CB away.
o The client disconnected. It might be forcing a retransmit of
CB operations, or it could have disconnected for other reasons.
Reschedule the CB so it is retransmitted when the client
reconnects.
Since callback operations can now be rescheduled, ensure that
cb_ops->prepare can be called only once by moving the
cb_ops->prepare paragraph down to just before the rpc_call_async()
call.
Fixes: 2bbfed98a4 ("nfsd: Fix races between nfsd4_cb_release() and nfsd4_shutdown_callback()")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Normally, NFSv4 callback operations are supposed to be sent to the
client as soon as they are queued up.
In a moment, I will introduce a recovery path where the server has
to wait for the client to reconnect. We don't want a hard busy wait
here -- the callback should be requeued to try again in several
milliseconds.
For now, convert nfsd4_callback from struct work_struct to struct
delayed_work, and queue with a zero delay argument. This should
avoid behavior changes for current operation.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
I noticed that once an NFSv4.1 callback operation gets a
NFS4ERR_DELAY status on CB_SEQUENCE and then the connection is lost,
the callback client loops, resending it indefinitely.
The switch arm in nfsd4_cb_sequence_done() that handles
NFS4ERR_DELAY uses rpc_restart_call() to rearm the RPC state machine
for the retransmit, but that path does not call the rpc_prepare_call
callback again. Thus cb_seq_status is set to -10008 by the first
NFS4ERR_DELAY result, but is never set back to 1 for the retransmits.
nfsd4_cb_sequence_done() thinks it's getting nothing but a
long series of CB_SEQUENCE NFS4ERR_DELAY replies.
Fixes: 7ba6cad6c8 ("nfsd: New helper nfsd4_cb_sequence_done() for processing more cb errors")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The final bit of stats that is global is the rpc svc_stat. Move this
into the nfsd_net struct and use that everywhere instead of the global
struct. Remove the unused global struct.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This is the last global stat, take it out of the nfsd_stats struct and
make it a global part of nfsd, report it the same as always.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
We have a global set of counters that we modify for all of the nfsd
operations, but now that we're exposing these stats across all network
namespaces we need to make the stats also be per-network namespace. We
already have some caching stats that are per-network namespace, so move
these definitions into the same counter and then adjust all the helpers
and users of these stats to provide the appropriate nfsd_net struct so
that the stats are maintained for the per-network namespace objects.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
We are running nfsd servers inside of containers with their own network
namespace, and we want to monitor these services using the stats found
in /proc. However these are not exposed in the proc inside of the
container, so we have to bind mount the host /proc into our containers
to get at this information.
Separate out the stat counters init and the proc registration, and move
the proc registration into the pernet operations entry and exit points
so that these stats can be exposed inside of network namespaces.
This is an intermediate step, this just exposes the global counters in
the network namespace. Subsequent patches will move these counters into
the per-network namespace container.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
We're going to merge the stats all into per network namespace in
subsequent patches, rename these nn counters to be consistent with the
rest of the stats.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
nfsd is the only thing using this helper, and it doesn't use the private
currently. When we switch to per-network namespace stats we will need
the struct net * in order to get to the nfsd_net. Use the net as the
proc private so we can utilize this when we make the switch over.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Since only one service actually reports the rpc stats there's not much
of a reason to have a pointer to it in the svc_program struct. Adjust
the svc_create_pooled function to take the sv_stats as an argument and
pass the struct through there as desired instead of getting it from the
svc_program->pg_stats.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
A lot of places are setting a blank svc_stats in ->pg_stats and never
utilizing these stats. Remove all of these extra structs as we're not
reporting these stats anywhere.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
We check for the existence of ->sv_stats elsewhere except in the core
processing code. It appears that only nfsd actual exports these values
anywhere, everybody else just has a write only copy of sv_stats in their
svc_program. Add a check for ->sv_stats before every adjustment to
allow us to eliminate the stats struct from all the users who don't
report the stats.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The maxcount is the maximum number of bytes for the LISTXATTRS4resok
result. This includes the cookie and the count for the name array,
thus subtract 12 bytes from the maxcount: 8 (cookie) + 4 (array count)
when filling up the name array.
Fixes: 23e50fe3a5 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
If the XDR buffer is not large enough to fit all attributes
and the remaining bytes left in the XDR buffer (xdrleft) is
equal to the number of bytes for the current attribute, then
the loop will prematurely exit without setting eof to FALSE.
Also in this case, adding the eof flag to the buffer will
make the reply 4 bytes larger than lsxa_maxcount.
Need to check if there are enough bytes to fit not only the
next attribute name but also the eof as well.
Fixes: 23e50fe3a5 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Function nfsd4_listxattr_validate_cookie() expects the cookie
as an offset to the list thus it needs to be encoded in big-endian.
Fixes: 23e50fe3a5 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
If LISTXATTRS is sent with a correct cookie but a small maxcount,
this could lead function nfsd4_listxattr_validate_cookie to
return NFS4ERR_BAD_COOKIE. If maxcount = 20, then second check
on function gives RHS = 3 thus any cookie larger than 3 returns
NFS4ERR_BAD_COOKIE.
There is no need to validate the cookie on the return XDR buffer
since attribute referenced by cookie will be the first in the
return buffer.
Fixes: 23e50fe3a5 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Calling fput() directly or though filp_close() from a kernel thread like
nfsd causes the final __fput() (if necessary) to be called from a
workqueue. This means that nfsd is not forced to wait for any work to
complete. If the ->release or ->destroy_inode function is slow for any
reason, this can result in nfsd closing files more quickly than the
workqueue can complete the close and the queue of pending closes can
grow without bounces (30 million has been seen at one customer site,
though this was in part due to a slowness in xfs which has since been
fixed).
nfsd does not need this. It is quite appropriate and safe for nfsd to
do its own close work. There is no reason that close should ever wait
for nfsd, so no deadlock can occur.
It should be safe and sensible to change all fput() calls to
__fput_sync(). However in the interests of caution this patch only
changes two - the two that can be most directly affected by client
behaviour and could occur at high frequency.
- the fput() implicitly in flip_close() is changed to __fput_sync()
by calling get_file() first to ensure filp_close() doesn't do
the final fput() itself. If is where files opened for IO are closed.
- the fput() in nfsd_read() is also changed. This is where directories
opened for readdir are closed.
This ensure that minimal fput work is queued to the workqueue.
This removes the need for the flush_delayed_fput() call in
nfsd_file_close_inode_sync()
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The work of closing a file can have non-trivial cost. Doing it in a
separate work queue thread means that cost isn't imposed on the nfsd
threads and an imbalance can be created. This can result in files being
queued for the work queue more quickly that the work queue can process
them, resulting in unbounded growth of the queue and memory exhaustion.
To avoid this work imbalance that exhausts memory, this patch moves all
closing of files into the nfsd threads. This means that when the work
imposes a cost, that cost appears where it would be expected - in the
work of the nfsd thread. A subsequent patch will ensure the final
__fput() is called in the same (nfsd) thread which calls filp_close().
Files opened for NFSv3 are never explicitly closed by the client and are
kept open by the server in the "filecache", which responds to memory
pressure, is garbage collected even when there is no pressure, and
sometimes closes files when there is particular need such as for rename.
These files currently have filp_close() called in a dedicated work
queue, so their __fput() can have no effect on nfsd threads.
This patch discards the work queue and instead has each nfsd thread call
flip_close() on as many as 8 files from the filecache each time it acts
on a client request (or finds there are no pending client requests). If
there are more to be closed, more threads are woken. This spreads the
work of __fput() over multiple threads and imposes any cost on those
threads.
The number 8 is somewhat arbitrary. It needs to be greater than 1 to
ensure that files are closed more quickly than they can be added to the
cache. It needs to be small enough to limit the per-request delays that
will be imposed on clients when all threads are busy closing files.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Allocating and zeroing a buffer during every call to
krb5_etm_checksum() is inefficient. Instead, set aside a static
buffer that is the maximum crypto block size, and use a portion
(or all) of that.
Reported-by: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The creds and oa->data need to be freed in the error-handling paths after
their allocation. So this patch add these deallocations in the
corresponding paths.
Fixes: 1d658336b0 ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The ctx->mech_used.data allocated by kmemdup is not freed in neither
gss_import_v2_context nor it only caller gss_krb5_import_sec_context,
which frees ctx on error.
Thus, this patch reform the last call of gss_import_v2_context to the
gss_krb5_import_ctx_v2, preventing the memleak while keepping the return
formation.
Fixes: 47d8480776 ("gss_krb5: handle new context format from gssd")
Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Pull bcachefs fixes from Kent Overstreet:
"Some more mostly boring fixes, but some not
User reported ones:
- the BTREE_ITER_FILTER_SNAPSHOTS one fixes a really nasty
performance bug; user reported an untar initially taking two
seconds and then ~2 minutes
- kill a __GFP_NOFAIL in the buffered read path; this was a leftover
from the trickier fix to kill __GFP_NOFAIL in readahead, where we
can't return errors (and have to silently truncate the read
ourselves).
bcachefs can't use GFP_NOFAIL for folio state unlike iomap based
filesystems because our folio state is just barely too big, 2MB
hugepages cause us to exceed the 2 page threshhold for GFP_NOFAIL.
additionally, the flags argument was just buggy, we weren't
supplying GFP_KERNEL previously (!)"
* tag 'bcachefs-2024-02-25' of https://evilpiepirate.org/git/bcachefs:
bcachefs: fix bch2_save_backtrace()
bcachefs: Fix check_snapshot() memcpy
bcachefs: Fix bch2_journal_flush_device_pins()
bcachefs: fix iov_iter count underflow on sub-block dio read
bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btree
bcachefs: Kill __GFP_NOFAIL in buffered read path
bcachefs: fix backpointer_to_text() when dev does not exist
Pull two documentation build fixes from Jonathan Corbet:
- The XFS online fsck documentation uses incredibly deeply nested
subsection and list nesting; that broke the PDF docs build. Tweak a
parameter to tell LaTeX to allow the deeper nesting.
- Fix a 6.8 PDF-build regression
* tag 'docs-6.8-fixes3' of git://git.lwn.net/linux:
docs: translations: use attribute to store current language
docs: Instruct LaTeX to cope with deeper nesting
Pull USB fixes from Greg KH:
"Here are some small USB fixes for 6.8-rc6 to resolve some reported
problems. These include:
- regression fixes with typec tpcm code as reported by many
- cdnsp and cdns3 driver fixes
- usb role setting code bugfixes
- build fix for uhci driver
- ncm gadget driver bugfix
- MAINTAINERS entry update
All of these have been in linux-next all week with no reported issues
and there is at least one fix in here that is in Thorsten's regression
list that is being tracked"
* tag 'usb-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: typec: tpcm: Fix issues with power being removed during reset
MAINTAINERS: Drop myself as maintainer of TYPEC port controller drivers
usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs
Revert "usb: typec: tcpm: reset counter when enter into unattached state after try role"
usb: gadget: omap_udc: fix USB gadget regression on Palm TE
usb: dwc3: gadget: Don't disconnect if not started
usb: cdns3: fix memory double free when handle zero packet
usb: cdns3: fixed memory use after free at cdns3_gadget_ep_disable()
usb: roles: don't get/set_role() when usb_role_switch is unregistered
usb: roles: fix NULL pointer issue when put module's reference
usb: cdnsp: fixed issue with incorrect detecting CDNSP family controllers
usb: cdnsp: blocked some cdns3 specific code
usb: uhci-grlib: Explicitly include linux/platform_device.h
Pull tty/serial driver fixes from Greg KH:
"Here are three small serial/tty driver fixes for 6.8-rc6 that resolve
the following reported errors:
- riscv hvc console driver fix that was reported by many
- amba-pl011 serial driver fix for RS485 mode
- stm32 serial driver fix for RS485 mode
All of these have been in linux-next all week with no reported
problems"
* tag 'tty-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: amba-pl011: Fix DMA transmission in RS485 mode
serial: stm32: do not always set SER_RS485_RX_DURING_TX if RS485 is enabled
tty: hvc: Don't enable the RISC-V SBI console by default
Pull x86 fixes from Borislav Petkov:
- Make sure clearing CPU buffers using VERW happens at the latest
possible point in the return-to-userspace path, otherwise memory
accesses after the VERW execution could cause data to land in CPU
buffers again
* tag 'x86_urgent_for_v6.8_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM/VMX: Move VERW closer to VMentry for MDS mitigation
KVM/VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH
x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key
x86/entry_32: Add VERW just before userspace transition
x86/entry_64: Add VERW just before userspace transition
x86/bugs: Add asm helpers for executing VERW
Pull irq fixes from Borislav Petkov:
- Make sure GICv4 always gets initialized to prevent a kexec-ed kernel
from silently failing to set it up
- Do not call bus_get_dev_root() for the mbigen irqchip as it always
returns NULL - use NULL directly
- Fix hardware interrupt number truncation when assigning MSI
interrupts
- Correct sending end-of-interrupt messages to disabled interrupts
lines on RISC-V PLIC
* tag 'irq_urgent_for_v6.8_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/gic-v3-its: Do not assume vPE tables are preallocated
irqchip/mbigen: Don't use bus_get_dev_root() to find the parent
PCI/MSI: Prevent MSI hardware interrupt number truncation
irqchip/sifive-plic: Enable interrupt if needed before EOI
Pull erofs fix from Gao Xiang:
- Fix page refcount leak when looking up specific inodes
introduced by metabuf reworking
* tag 'erofs-for-6.8-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: fix refcount on the metabuf used for inode lookup
Pull RCU pathwalk fixes from Al Viro:
"We still have some races in filesystem methods when exposed to RCU
pathwalk. This series is a result of code audit (the second round of
it) and it should deal with most of that stuff.
Still pending: ntfs3 ->d_hash()/->d_compare() and ceph_d_revalidate().
Up to maintainers (a note for NTFS folks - when documentation says
that a method may not block, it *does* imply that blocking allocations
are to be avoided. Really)"
[ More explanations for people who aren't familiar with the vagaries of
RCU path walking: most of it is hidden from filesystems, but if a
filesystem actively participates in the low-level path walking it
needs to make sure the fields involved in that walk are RCU-safe.
That "actively participate in low-level path walking" includes things
like having its own ->d_hash()/->d_compare() routines, or by having
its own directory permission function that doesn't just use the common
helpers. Having a ->d_revalidate() function will also have this issue.
Note that instead of making everything RCU safe you can also choose to
abort the RCU pathwalk if your operation cannot be done safely under
RCU, but that obviously comes with a performance penalty. One common
pattern is to allow the simple cases under RCU, and abort only if you
need to do something more complicated.
So not everything needs to be RCU-safe, and things like the inode etc
that the VFS itself maintains obviously already are. But these fixes
tend to be about properly RCU-delaying things like ->s_fs_info that
are maintained by the filesystem and that got potentially released too
early. - Linus ]
* tag 'pull-fixes.pathwalk-rcu-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
ext4_get_link(): fix breakage in RCU mode
cifs_get_link(): bail out in unsafe case
fuse: fix UAF in rcu pathwalks
procfs: make freeing proc_fs_info rcu-delayed
procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
nfs: fix UAF on pathwalk running into umount
nfs: make nfs_set_verifier() safe for use in RCU pathwalk
afs: fix __afs_break_callback() / afs_drop_open_mmap() race
hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info
exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper
affs: free affs_sb_info with kfree_rcu()
rcu pathwalk: prevent bogus hard errors from may_lookup()
fs/super.c: don't drop ->s_user_ns until we free struct super_block itself
Pull vfs fixes from Al Viro:
"A couple of fixes - revert of regression from this cycle and a fix for
erofs failure exit breakage (had been there since way back)"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
erofs: fix handling kern_mount() failure
Revert "get rid of DCACHE_GENOCIDE"
1) errors from ext4_getblk() should not be propagated to caller
unless we are really sure that we would've gotten the same error
in non-RCU pathwalk.
2) we leak buffer_heads if ext4_getblk() is successful, but bh is
not uptodate.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
->d_revalidate() bails out there, anyway. It's not enough
to prevent getting into ->get_link() in RCU mode, but that
could happen only in a very contrieved setup. Not worth
trying to do anything fancy here unless ->d_revalidate()
stops kicking out of RCU mode at least in some cases.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
->permission(), ->get_link() and ->inode_get_acl() might dereference
->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns
as well) when called from rcu pathwalk.
Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info
and dropping ->user_ns rcu-delayed too.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
makes proc_pid_ns() safe from rcu pathwalk (put_pid_ns()
is still synchronous, but that's not a problem - it does
rcu-delay everything that needs to be)
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
that keeps both around until struct inode is freed, making access
to them safe from rcu-pathwalk
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
NFS ->d_revalidate(), ->permission() and ->get_link() need to access
some parts of nfs_server when called in RCU mode:
server->flags
server->caps
*(server->io_stats)
and, worst of all, call
server->nfs_client->rpc_ops->have_delegation
(the last one - as NFS_PROTO(inode)->have_delegation()). We really
don't want to RCU-delay the entire nfs_free_server() (it would have
to be done with schedule_work() from RCU callback, since it can't
be made to run from interrupt context), but actual freeing of
nfs_server and ->io_stats can be done via call_rcu() just fine.
nfs_client part is handled simply by making nfs_free_client() use
kfree_rcu().
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
nfs_set_verifier() relies upon dentry being pinned; if that's
the case, grabbing ->d_lock stabilizes ->d_parent and guarantees
that ->d_parent points to a positive dentry. For something
we'd run into in RCU mode that is *not* true - dentry might've
been through dentry_kill() just as we grabbed ->d_lock, with
its parent going through the same just as we get to into
nfs_set_verifier_locked(). It might get to detaching inode
(and zeroing ->d_inode) before nfs_set_verifier_locked() gets
to fetching that; we get an oops as the result.
That can happen in nfs{,4} ->d_revalidate(); the call chain in
question is nfs_set_verifier_locked() <- nfs_set_verifier() <-
nfs_lookup_revalidate_delegated() <- nfs{,4}_do_lookup_revalidate().
We have checked that the parent had been positive, but that's
done before we get to nfs_set_verifier() and it's possible for
memory pressure to pick our dentry as eviction candidate by that
time. If that happens, back-to-back attempts to kill dentry and
its parent are quite normal. Sure, in case of eviction we'll
fail the ->d_seq check in the caller, but we need to survive
until we return there...
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In __afs_break_callback() we might check ->cb_nr_mmap and if it's non-zero
do queue_work(&vnode->cb_work). In afs_drop_open_mmap() we decrement
->cb_nr_mmap and do flush_work(&vnode->cb_work) if it reaches zero.
The trouble is, there's nothing to prevent __afs_break_callback() from
seeing ->cb_nr_mmap before the decrement and do queue_work() after both
the decrement and flush_work(). If that happens, we might be in trouble -
vnode might get freed before the queued work runs.
__afs_break_callback() is always done under ->cb_lock, so let's make
sure that ->cb_nr_mmap can change from non-zero to zero while holding
->cb_lock (the spinlock component of it - it's a seqlock and we don't
need to mess with the counter).
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
->d_hash() and ->d_compare() use those, so we need to delay freeing
them.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
