Commit Graph

64610 Commits

Author SHA1 Message Date
Pavel Begunkov
650b548129 io_uring: don't prepare DRAIN reqs twice
If req->io is not NULL, it's already prepared. Don't do it again,
it's dangerous.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 09:22:09 -06:00
Jens Axboe
583863ed91 io_uring: initialize ctx->sqo_wait earlier
Ensure that ctx->sqo_wait is initialized as soon as the ctx is allocated,
instead of deferring it to the offload setup. This fixes a syzbot
reported lockdep complaint, which is really due to trying to wake_up
on an uninitialized wait queue:

RSP: 002b:00007fffb1fb9aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441319
RDX: 0000000000000001 RSI: 0000000020000140 RDI: 000000000000047b
RBP: 0000000000010475 R08: 0000000000000001 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402260
R13: 00000000004022f0 R14: 0000000000000000 R15: 0000000000000000
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 7090 Comm: syz-executor222 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 assign_lock_key kernel/locking/lockdep.c:913 [inline]
 register_lock_class+0x1664/0x1760 kernel/locking/lockdep.c:1225
 __lock_acquire+0x104/0x4c50 kernel/locking/lockdep.c:4234
 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
 __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122
 io_cqring_ev_posted+0xa5/0x1e0 fs/io_uring.c:1160
 io_poll_remove_all fs/io_uring.c:4357 [inline]
 io_ring_ctx_wait_and_kill+0x2bc/0x5a0 fs/io_uring.c:7305
 io_uring_create fs/io_uring.c:7843 [inline]
 io_uring_setup+0x115e/0x22b0 fs/io_uring.c:7870
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x441319
Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffb1fb9aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9

Reported-by: syzbot+8c91f5d054e998721c57@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 09:20:00 -06:00
Linus Torvalds
5a9ffb954a Merge tag '5.7-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs fixes from Steve French:
 "Three small cifs/smb3 fixes, one for stable"

* tag '5.7-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix leaked reference on requeued write
  cifs: Fix null pointer check in cifs_read
  CIFS: Spelling s/EACCESS/EACCES/
2020-05-16 21:43:11 -07:00
Linus Torvalds
18e70f3a76 Merge tag 'io_uring-5.7-2020-05-15' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
 "Two small fixes that should go into this release:

   - Check and handle zero length splice (Pavel)

   - Fix a regression in this merge window for fixed files used with
     polled block IO"

* tag 'io_uring-5.7-2020-05-15' of git://git.kernel.dk/linux-block:
  io_uring: polled fixed file must go through free iteration
  io_uring: fix zero len do_splice()
2020-05-16 13:17:41 -07:00
Linus Torvalds
12bf0b632e Merge tag 'nfs-for-5.7-5' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Stable fixes:
   - nfs: fix NULL deference in nfs4_get_valid_delegation

  Bugfixes:
   - Fix corruption of the return value in cachefiles_read_or_alloc_pages()
   - Fix several fscache cookie issues
   - Fix a fscache queuing race that can trigger a BUG_ON
   - NFS: Fix two use-after-free regressions due to the RPC_TASK_CRED_NOREF flag
   - SUNRPC: Fix a use-after-free regression in rpc_free_client_work()
   - SUNRPC: Fix a race when tearing down the rpc client debugfs directory
   - SUNRPC: Signalled ASYNC tasks need to exit
   - NFSv3: fix rpc receive buffer size for MOUNT call"

* tag 'nfs-for-5.7-5' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv3: fix rpc receive buffer size for MOUNT call
  SUNRPC: 'Directory with parent 'rpc_clnt' already present!'
  NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs
  NFS: Don't use RPC_TASK_CRED_NOREF with delegreturn
  SUNRPC: Signalled ASYNC tasks need to exit
  nfs: fix NULL deference in nfs4_get_valid_delegation
  SUNRPC: fix use-after-free in rpc_free_client_work()
  cachefiles: Fix race between read_waiter and read_copier involving op->to_do
  NFSv4: Fix fscache cookie aux_data to ensure change_attr is included
  NFS: Fix fscache super_cookie allocation
  NFS: Fix fscache super_cookie index_key from changing after umount
  cachefiles: Fix corruption of the return value in cachefiles_read_or_alloc_pages()
2020-05-15 14:03:13 -07:00
Eric Biggers
cdeb21da17 fscrypt: add fscrypt_add_test_dummy_key()
Currently, the test_dummy_encryption mount option (which is used for
encryption I/O testing with xfstests) uses v1 encryption policies, and
it relies on userspace inserting a test key into the session keyring.

We need test_dummy_encryption to support v2 encryption policies too.
Requiring userspace to add the test key doesn't work well with v2
policies, since v2 policies only support the filesystem keyring (not the
session keyring), and keys in the filesystem keyring are lost when the
filesystem is unmounted.  Hooking all test code that unmounts and
re-mounts the filesystem would be difficult.

Instead, let's make the filesystem automatically add the test key to its
keyring when test_dummy_encryption is enabled.

That puts the responsibility for choosing the test key on the kernel.
We could just hard-code a key.  But out of paranoia, let's first try
using a per-boot random key, to prevent this code from being misused.
A per-boot key will work as long as no one expects dummy-encrypted files
to remain accessible after a reboot.  (gce-xfstests doesn't.)

Therefore, this patch adds a function fscrypt_add_test_dummy_key() which
implements the above.  The next patch will use it.

Link: https://lore.kernel.org/r/20200512233251.118314-3-ebiggers@kernel.org
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-15 13:51:45 -07:00
David S. Miller
da07f52d3c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Move the bpf verifier trace check into the new switch statement in
HEAD.

Resolve the overlapping changes in hinic, where bug fixes overlap
the addition of VF support.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-15 13:48:59 -07:00
Jens Axboe
6a4d07cde5 io_uring: file registration list and lock optimization
There's no point in using list_del_init() on entries that are going
away, and the associated lock is always used in process context so
let's not use the IRQ disabling+saving variant of the spinlock.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 14:37:14 -06:00
Stefano Garzarella
7e55a19cf6 io_uring: add IORING_CQ_EVENTFD_DISABLED to the CQ ring flags
This new flag should be set/clear from the application to
disable/enable eventfd notifications when a request is completed
and queued to the CQ ring.

Before this patch, notifications were always sent if an eventfd is
registered, so IORING_CQ_EVENTFD_DISABLED is not set during the
initialization.

It will be up to the application to set the flag after initialization
if no notifications are required at the beginning.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 12:16:59 -06:00
Stefano Garzarella
0d9b5b3af1 io_uring: add 'cq_flags' field for the CQ ring
This patch adds the new 'cq_flags' field that should be written by
the application and read by the kernel.

This new field is available to the userspace application through
'cq_off.flags'.
We are using 4-bytes previously reserved and set to zero. This means
that if the application finds this field to zero, then the new
functionality is not supported.

In the next patch we will introduce the first flag available.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 12:16:59 -06:00
Jens Axboe
18bceab101 io_uring: allow POLL_ADD with double poll_wait() users
Some file descriptors use separate waitqueues for their f_ops->poll()
handler, most commonly one for read and one for write. The io_uring
poll implementation doesn't work with that, as the 2nd poll_wait()
call will cause the io_uring poll request to -EINVAL.

This affects (at least) tty devices and /dev/random as well. This is a
big problem for event loops where some file descriptors work, and others
don't.

With this fix, io_uring handles multiple waitqueues.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 11:56:54 -06:00
Jens Axboe
4a38aed2a0 io_uring: batch reap of dead file registrations
We currently embed and queue a work item per fixed_file_ref_node that
we update, but if the workload does a lot of these, then the associated
kworker-events overhead can become quite noticeable.

Since we rarely need to wait on these, batch them at 1 second intervals
instead. If we do need to wait for them, we just flush the pending
delayed work.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 11:56:18 -06:00
Sami Tolvanen
628d06a48f scs: Add page accounting for shadow call stack allocations
This change adds accounting for the memory allocated for shadow stacks.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-15 16:35:49 +01:00
David S. Miller
d00f26b623 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-05-14

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Merged tag 'perf-for-bpf-2020-05-06' from tip tree that includes CAP_PERFMON.

2) support for narrow loads in bpf_sock_addr progs and additional
   helpers in cg-skb progs, from Andrey.

3) bpf benchmark runner, from Andrii.

4) arm and riscv JIT optimizations, from Luke.

5) bpf iterator infrastructure, from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-14 20:31:21 -07:00
Jens Axboe
0f158b4cf2 io_uring: name sq thread and ref completions
We used to have three completions, now we just have two. With the two,
let's not allocate them dynamically, just embed then in the ctx and
name them appropriately.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-14 17:18:39 -06:00
Adam McCoy
a481379960 cifs: fix leaked reference on requeued write
Failed async writes that are requeued may not clean up a refcount
on the file, which can result in a leaked open. This scenario arises
very reliably when using persistent handles and a reconnect occurs
while writing.

cifs_writev_requeue only releases the reference if the write fails
(rc != 0). The server->ops->async_writev operation will take its own
reference, so the initial reference can always be released.

Signed-off-by: Adam McCoy <adam@forsedomani.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-05-14 17:47:01 -05:00
Olga Kornievskaia
8eed292bc8 NFSv3: fix rpc receive buffer size for MOUNT call
Prior to commit e3d3ab64dd66 ("SUNRPC: Use au_rslack when
computing reply buffer size"), there was enough slack in the reply
buffer to commodate filehandles of size 60bytes. However, the real
problem was that the reply buffer size for the MOUNT operation was
not correctly calculated. Received buffer size used the filehandle
size for NFSv2 (32bytes) which is much smaller than the allowed
filehandle size for the v3 mounts.

Fix the reply buffer size (decode arguments size) for the MNT command.

Fixes: 2c94b8eca1 ("SUNRPC: Use au_rslack when computing reply buffer size")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-05-14 18:42:44 -04:00
Roman Penyaev
65759097d8 epoll: call final ep_events_available() check under the lock
There is a possible race when ep_scan_ready_list() leaves ->rdllist and
->obflist empty for a short period of time although some events are
pending.  It is quite likely that ep_events_available() observes empty
lists and goes to sleep.

Since commit 339ddb53d3 ("fs/epoll: remove unnecessary wakeups of
nested epoll") we are conservative in wakeups (there is only one place
for wakeup and this is ep_poll_callback()), thus ep_events_available()
must always observe correct state of two lists.

The easiest and correct way is to do the final check under the lock.
This does not impact the performance, since lock is taken anyway for
adding a wait entry to the wait queue.

The discussion of the problem can be found here:

   https://lore.kernel.org/linux-fsdevel/a2f22c3c-c25a-4bda-8339-a7bdaf17849e@akamai.com/

In this patch barrierless __set_current_state() is used.  This is safe
since waitqueue_active() is called under the same lock on wakeup side.

Short-circuit for fatal signals (i.e.  fatal_signal_pending() check) is
moved to the line just before actual events harvesting routine.  This is
fully compliant to what is said in the comment of the patch where the
actual fatal_signal_pending() check was added: c257a340ed ("fs, epoll:
short circuit fetching events if thread has been killed").

Fixes: 339ddb53d3 ("fs/epoll: remove unnecessary wakeups of nested epoll")
Reported-by: Jason Baron <jbaron@akamai.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Baron <jbaron@akamai.com>
Cc: Khazhismel Kumykov <khazhy@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200505145609.1865152-1-rpenyaev@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-14 10:00:35 -07:00
Steve French
9bd21d4b1a cifs: Fix null pointer check in cifs_read
Coverity scan noted a redundant null check

Coverity-id: 728517
Reported-by: Coverity <scan-admin@coverity.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>
2020-05-14 10:30:03 -05:00
Miklos Szeredi
c8ffd8bcdd vfs: add faccessat2 syscall
POSIX defines faccessat() as having a fourth "flags" argument, while the
linux syscall doesn't have it.  Glibc tries to emulate AT_EACCESS and
AT_SYMLINK_NOFOLLOW, but AT_EACCESS emulation is broken.

Add a new faccessat(2) syscall with the added flags argument and implement
both flags.

The value of AT_EACCESS is defined in glibc headers to be the same as
AT_REMOVEDIR.  Use this value for the kernel interface as well, together
with the explanatory comment.

Also add AT_EMPTY_PATH support, which is not documented by POSIX, but can
be useful and is trivial to implement.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-14 16:44:25 +02:00
Miklos Szeredi
55923e4d7d vfs: don't parse "silent" option
Parsing "silent" and clearing SB_SILENT makes zero sense.

Parsing "silent" and setting SB_SILENT would make a bit more sense, but
apparently nobody cares.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:25 +02:00
Miklos Szeredi
caaef1ba8c vfs: don't parse "posixacl" option
Unlike the others, this is _not_ a standard option accepted by mount(8).

In fact SB_POSIXACL is an internal flag, and accepting MS_POSIXACL on the
mount(2) interface is possibly a bug.

The only filesystem that apparently wants to handle the "posixacl" option
is 9p, but it has special handling of that option besides setting
SB_POSIXACL.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:25 +02:00
Miklos Szeredi
9193ae87a8 vfs: don't parse forbidden flags
Makes little sense to keep this blacklist synced with what mount(8) parses
and what it doesn't.  E.g. it has various forms of "*atime" options, but
not "atime"...

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:25 +02:00
Miklos Szeredi
80340fe360 statx: add mount_root
Determining whether a path or file descriptor refers to a mountpoint (or
more precisely a mount root) is not trivial using current tools.

Add a flag to statx that indicates whether the path or fd refers to the
root of a mount or not.

Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Reported-by: Lennart Poettering <mzxreary@0pointer.de>
Reported-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
fa2fcf4f1d statx: add mount ID
Systemd is hacking around to get it and it's trivial to add to statx, so...

Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
761e28fa27 statx: don't clear STATX_ATIME on SB_RDONLY
IS_NOATIME(inode) is defined as __IS_FLG(inode, SB_RDONLY|SB_NOATIME), so
generic_fillattr() will clear STATX_ATIME from the result_mask if the super
block is marked read only.

This was probably not the intention, so fix to only clear STATX_ATIME if
the fs doesn't support atime at all.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
581701b7ef uapi: deprecate STATX_ALL
Constants of the *_ALL type can be actively harmful due to the fact that
developers will usually fail to consider the possible effects of future
changes to the definition.

Deprecate STATX_ALL in the uapi, while no damage has been done yet.

We could keep something like this around in the kernel, but there's
actually no point, since all filesystems should be explicitly checking
flags that they support and not rely on the VFS masking unknown ones out: a
flag could be known to the VFS, yet not known to the filesystem.

Cc: David Howells <dhowells@redhat.com>
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
44a3b87444 utimensat: AT_EMPTY_PATH support
This makes it possible to use utimensat on an O_PATH file (including
symlinks).

It supersedes the nonstandard utimensat(fd, NULL, ...) form.

Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
9470451505 vfs: split out access_override_creds()
Split out a helper that overrides the credentials in preparation for
actually doing the access check.

This prepares for the next patch that optionally disables the creds
override.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
9f6c61f96f proc/mounts: add cursor
If mounts are deleted after a read(2) call on /proc/self/mounts (or its
kin), the subsequent read(2) could miss a mount that comes after the
deleted one in the list.  This is because the file position is interpreted
as the number mount entries from the start of the list.

E.g. first read gets entries #0 to #9; the seq file index will be 10.  Then
entry #5 is deleted, resulting in #10 becoming #9 and #11 becoming #10,
etc...  The next read will continue from entry #10, and #9 is missed.

Solve this by adding a cursor entry for each open instance.  Taking the
global namespace_sem for write seems excessive, since we are only dealing
with a per-namespace list.  Instead add a per-namespace spinlock and use
that together with namespace_sem taken for read to protect against
concurrent modification of the mount list.  This may reduce parallelism of
is_local_mountpoint(), but it's hardly a big contention point.  We could
also use RCU freeing of cursors to make traversal not need additional
locks, if that turns out to be neceesary.

Only move the cursor once for each read (cursor is not added on open) to
minimize cacheline invalidation.  When EOF is reached, the cursor is taken
off the list, in order to prevent an excessive number of cursors due to
inactive open file descriptors.

Reported-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
530f32fc37 aio: fix async fsync creds
Avi Kivity reports that on fuse filesystems running in a user namespace
asyncronous fsync fails with EOVERFLOW.

The reason is that f_ops->fsync() is called with the creds of the kthread
performing aio work instead of the creds of the process originally
submitting IOCB_CMD_FSYNC.

Fuse sends the creds of the caller in the request header and it needs to
translate the uid and gid into the server's user namespace.  Since the
kthread is running in init_user_ns, the translation will fail and the
operation returns an error.

It can be argued that fsync doesn't actually need any creds, but just
zeroing out those fields in the header (as with requests that currently
don't take creds) is a backward compatibility risk.

Instead of working around this issue in fuse, solve the core of the problem
by calling the filesystem with the proper creds.

Reported-by: Avi Kivity <avi@scylladb.com>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: c9582eb0ff ("fuse: Fail all requests with invalid uids or gids")
Cc: stable@vger.kernel.org  # 4.18+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi
a3c751a50f vfs: allow unprivileged whiteout creation
Whiteouts, unlike real device node should not require privileges to create.

The general concern with device nodes is that opening them can have side
effects.  The kernel already avoids zero major (see
Documentation/admin-guide/devices.txt).  To be on the safe side the patch
explicitly forbids registering a char device with 0/0 number (see
cdev_add()).

This guarantees that a non-O_PATH open on a whiteout will fail with ENODEV;
i.e. it won't have any side effect.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-14 16:44:23 +02:00
Nishad Kamdar
508578f2f5 xfs: Use the correct style for SPDX License Identifier
This patch corrects the SPDX License Identifier style in header files
related to XFS File System support. For C header files
Documentation/process/license-rules.rst mandates C-like comments.
(opposed to C source files where C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-13 15:32:45 -07:00
Gustavo A. R. Silva
ee4064e56c xfs: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-13 15:32:45 -07:00
Zheng Bin
237aac4624 xfs: ensure f_bfree returned by statfs() is non-negative
Construct an img like this:

dd if=/dev/zero of=xfs.img bs=1M count=20
mkfs.xfs -d agcount=1 xfs.img
xfs_db -x xfs.img
sb 0
write fdblocks 0
agf 0
write freeblks 0
write longest 0
quit

mount it, df -h /mnt(xfs mount point), will show this:
Filesystem      Size  Used Avail Use% Mounted on
/dev/loop0       17M  -64Z  -32K 100% /mnt

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-13 15:32:45 -07:00
Jens Axboe
9d9e88a24c io_uring: polled fixed file must go through free iteration
When we changed the file registration handling, it became important to
iterate the bulk request freeing list for fixed files as well, or we
miss dropping the fixed file reference. If not, we're leaking references,
and we'll get a kworker stuck waiting for file references to disappear.

This also means we can remove the special casing of fixed vs non-fixed
files, we need to iterate for both and we can just rely on
__io_req_aux_free() doing io_put_file() instead of doing it manually.

Fixes: 0558955373 ("io_uring: refactor file register/unregister/update handling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-13 13:00:00 -06:00
Ira Weiny
2c567af418 fs: Introduce DCACHE_DONTCACHE
DCACHE_DONTCACHE indicates a dentry should not be cached on final
dput().

Also add a helper function to mark DCACHE_DONTCACHE on all dentries
pointing to a specific inode when that inode is being set I_DONTCACHE.

This facilitates dropping dentry references to inodes sooner which
require eviction to swap S_DAX mode.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-13 08:44:35 -07:00
Ira Weiny
dae2f8ed79 fs: Lift XFS_IDONTCACHE to the VFS layer
DAX effective mode (S_DAX) changes requires inode eviction.

XFS has an advisory flag (XFS_IDONTCACHE) to prevent caching of the
inode if no other additional references are taken.  We lift this flag to
the VFS layer and change the behavior slightly by allowing the flag to
remain even if multiple references are taken.

This will expedite the eviction of inodes to change S_DAX.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-13 08:44:35 -07:00
Trond Myklebust
4fa7ef69e2 NFS/pnfs: Don't use RPC_TASK_CRED_NOREF with pnfs
When we're doing pnfs then the credential being used for the RPC call
is not necessarily the same as the one used in the open context, so
don't use RPC_TASK_CRED_NOREF.

Fixes: 6129650720 ("NFSv4: Avoid referencing the cred unnecessarily during NFSv4 I/O")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-05-13 09:55:36 -04:00
Christian Brauner
303cc571d1 nsproxy: attach to namespaces via pidfds
For quite a while we have been thinking about using pidfds to attach to
namespaces. This patchset has existed for about a year already but we've
wanted to wait to see how the general api would be received and adopted.
Now that more and more programs in userspace have started using pidfds
for process management it's time to send this one out.

This patch makes it possible to use pidfds to attach to the namespaces
of another process, i.e. they can be passed as the first argument to the
setns() syscall. When only a single namespace type is specified the
semantics are equivalent to passing an nsfd. That means
setns(nsfd, CLONE_NEWNET) equals setns(pidfd, CLONE_NEWNET). However,
when a pidfd is passed, multiple namespace flags can be specified in the
second setns() argument and setns() will attach the caller to all the
specified namespaces all at once or to none of them. Specifying 0 is not
valid together with a pidfd.

Here are just two obvious examples:
setns(pidfd, CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWNET);
setns(pidfd, CLONE_NEWUSER);
Allowing to also attach subsets of namespaces supports various use-cases
where callers setns to a subset of namespaces to retain privilege, perform
an action and then re-attach another subset of namespaces.

If the need arises, as Eric suggested, we can extend this patchset to
assume even more context than just attaching all namespaces. His suggestion
specifically was about assuming the process' root directory when
setns(pidfd, 0) or setns(pidfd, SETNS_PIDFD) is specified. For now, just
keep it flexible in terms of supporting subsets of namespaces but let's
wait until we have users asking for even more context to be assumed. At
that point we can add an extension.

The obvious example where this is useful is a standard container
manager interacting with a running container: pushing and pulling files
or directories, injecting mounts, attaching/execing any kind of process,
managing network devices all these operations require attaching to all
or at least multiple namespaces at the same time. Given that nowadays
most containers are spawned with all namespaces enabled we're currently
looking at at least 14 syscalls, 7 to open the /proc/<pid>/ns/<ns>
nsfds, another 7 to actually perform the namespace switch. With time
namespaces we're looking at about 16 syscalls.
(We could amortize the first 7 or 8 syscalls for opening the nsfds by
 stashing them in each container's monitor process but that would mean
 we need to send around those file descriptors through unix sockets
 everytime we want to interact with the container or keep on-disk
 state. Even in scenarios where a caller wants to join a particular
 namespace in a particular order callers still profit from batching
 other namespaces. That mostly applies to the user namespace but
 all container runtimes I found join the user namespace first no matter
 if it privileges or deprivileges the container similar to how unshare
 behaves.)
With pidfds this becomes a single syscall no matter how many namespaces
are supposed to be attached to.

A decently designed, large-scale container manager usually isn't the
parent of any of the containers it spawns so the containers don't die
when it crashes or needs to update or reinitialize. This means that
for the manager to interact with containers through pids is inherently
racy especially on systems where the maximum pid number is not
significicantly bumped. This is even more problematic since we often spawn
and manage thousands or ten-thousands of containers. Interacting with a
container through a pid thus can become risky quite quickly. Especially
since we allow for an administrator to enable advanced features such as
syscall interception where we're performing syscalls in lieu of the
container. In all of those cases we use pidfds if they are available and
we pass them around as stable references. Using them to setns() to the
target process' namespaces is as reliable as using nsfds. Either the
target process is already dead and we get ESRCH or we manage to attach
to its namespaces but we can't accidently attach to another process'
namespaces. So pidfds lend themselves to be used with this api.
The other main advantage is that with this change the pidfd becomes the
only relevant token for most container interactions and it's the only
token we need to create and send around.

Apart from significiantly reducing the number of syscalls from double
digit to single digit which is a decent reason post-spectre/meltdown
this also allows to switch to a set of namespaces atomically, i.e.
either attaching to all the specified namespaces succeeds or we fail. If
we fail we haven't changed a single namespace. There are currently three
namespaces that can fail (other than for ENOMEM which really is not
very interesting since we then have other problems anyway) for
non-trivial reasons, user, mount, and pid namespaces. We can fail to
attach to a pid namespace if it is not our current active pid namespace
or a descendant of it. We can fail to attach to a user namespace because
we are multi-threaded or because our current mount namespace shares
filesystem state with other tasks, or because we're trying to setns()
to the same user namespace, i.e. the target task has the same user
namespace as we do. We can fail to attach to a mount namespace because
it shares filesystem state with other tasks or because we fail to lookup
the new root for the new mount namespace. In most non-pathological
scenarios these issues can be somewhat mitigated. But there are cases where
we're half-attached to some namespace and failing to attach to another one.
I've talked about some of these problem during the hallway track (something
only the pre-COVID-19 generation will remember) of Plumbers in Los Angeles
in 2018(?). Even if all these issues could be avoided with super careful
userspace coding it would be nicer to have this done in-kernel. Pidfds seem
to lend themselves nicely for this.

The other neat thing about this is that setns() becomes an actual
counterpart to the namespace bits of unshare().

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Jann Horn <jannh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20200505140432.181565-3-christian.brauner@ubuntu.com
2020-05-13 11:41:22 +02:00
Dan Carpenter
9aafc1b018 ovl: potential crash in ovl_fid_to_fh()
The "buflen" value comes from the user and there is a potential that it
could be zero.  In do_handle_to_path() we know that "handle->handle_bytes"
is non-zero and we do:

	handle_dwords = handle->handle_bytes >> 2;

So values 1-3 become zero.  Then in ovl_fh_to_dentry() we do:

	int len = fh_len << 2;

So now len is in the "0,4-128" range and a multiple of 4.  But if
"buflen" is zero it will try to copy negative bytes when we do the
memcpy in ovl_fid_to_fh().

	memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET);

And that will lead to a crash.  Thanks to Amir Goldstein for his help
with this patch.

Fixes: cbe7fba8ed ("ovl: make sure that real fid is 32bit aligned in memory")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Cc: <stable@vger.kernel.org> # v5.5
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-13 11:10:57 +02:00
Johannes Thumshirn
02ef12a663 zonefs: use REQ_OP_ZONE_APPEND for sync DIO
Synchronous direct I/O to a sequential write only zone can be issued using
the new REQ_OP_ZONE_APPEND request operation. As dispatching multiple
BIOs can potentially result in reordering, we cannot support asynchronous
IO via this interface.

We also can only dispatch up to queue_max_zone_append_sectors() via the
new zone-append method and have to return a short write back to user-space
in case an IO larger than queue_max_zone_append_sectors() has been issued.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-12 20:36:28 -06:00
Ming Lei
e6249cdd46 block: add blk_io_schedule() for avoiding task hung in sync dio
Sync dio could be big, or may take long time in discard or in case of
IO failure.

We have prevented task hung in submit_bio_wait() and blk_execute_rq(),
so apply the same trick for prevent task hung from happening in sync dio.

Add helper of blk_io_schedule() and use io_schedule_timeout() to prevent
task hung warning.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Cc: Salman Qazi <sqazi@google.com>
Cc: Jesse Barnes <jsbarnes@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-12 20:32:42 -06:00
Eric Biggers
9cd6b593cf fs-verity: remove unnecessary extern keywords
Remove the unnecessary 'extern' keywords from function declarations.
This makes it so that we don't have a mix of both styles, so it won't be
ambiguous what to use in new fs-verity patches.  This also makes the
code shorter and matches the 'checkpatch --strict' expectation.

Link: https://lore.kernel.org/r/20200511192118.71427-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-12 16:44:00 -07:00
Eric Biggers
6377a38bd3 fs-verity: fix all kerneldoc warnings
Fix all kerneldoc warnings in fs/verity/ and include/linux/fsverity.h.
Most of these were due to missing documentation for function parameters.

Detected with:

    scripts/kernel-doc -v -none fs/verity/*.{c,h} include/linux/fsverity.h

This cleanup makes it possible to check new patches for kerneldoc
warnings without having to filter out all the existing ones.

Link: https://lore.kernel.org/r/20200511192118.71427-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-12 16:43:59 -07:00
Eric Biggers
607009020a fscrypt: remove unnecessary extern keywords
Remove the unnecessary 'extern' keywords from function declarations.
This makes it so that we don't have a mix of both styles, so it won't be
ambiguous what to use in new fscrypt patches.  This also makes the code
shorter and matches the 'checkpatch --strict' expectation.

Link: https://lore.kernel.org/r/20200511191358.53096-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-12 16:37:17 -07:00
Eric Biggers
d2fe97545a fscrypt: fix all kerneldoc warnings
Fix all kerneldoc warnings in fs/crypto/ and include/linux/fscrypt.h.
Most of these were due to missing documentation for function parameters.

Detected with:

    scripts/kernel-doc -v -none fs/crypto/*.{c,h} include/linux/fscrypt.h

This cleanup makes it possible to check new patches for kerneldoc
warnings without having to filter out all the existing ones.

For consistency, also adjust some function "brief descriptions" to
include the parentheses and to wrap at 80 characters.  (The latter
matches the checkpatch expectation.)

Link: https://lore.kernel.org/r/20200511191358.53096-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-12 16:37:17 -07:00
Linus Torvalds
e719340f46 Merge tag 'gfs2-v5.7-rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 fixes from Andreas Gruenbacher:
 "Various gfs2 fixes.

  Fixes for bugs prior to v5.7:
   - Fix random block reads when reading fragmented journals (v5.2)
   - Fix a possible random memory access in gfs2_walk_metadata (v5.3)

  Fixes for v5.7:
   - Fix several overlooked gfs2_qa_get / gfs2_qa_put imbalances
   - Fix several bugs in the new filesystem withdraw logic"

* tag 'gfs2-v5.7-rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  Revert "gfs2: Don't demote a glock until its revokes are written"
  gfs2: If go_sync returns error, withdraw but skip invalidate
  gfs2: Grab glock reference sooner in gfs2_add_revoke
  gfs2: don't call quota_unhold if quotas are not locked
  gfs2: move privileged user check to gfs2_quota_lock_check
  gfs2: remove check for quotas on in gfs2_quota_check
  gfs2: Change BUG_ON to an assert_withdraw in gfs2_quota_change
  gfs2: Fix problems regarding gfs2_qa_get and _put
  gfs2: More gfs2_find_jhead fixes
  gfs2: Another gfs2_walk_metadata fix
  gfs2: Fix use-after-free in gfs2_logd after withdraw
  gfs2: Fix BUG during unmount after file system withdraw
  gfs2: Fix error exit in do_xmote
  gfs2: fix withdraw sequence deadlock
2020-05-12 10:32:32 -07:00
Kees Cook
7a0ad54684 pstore: Refactor pstorefs record list removal
The "unlink" handling should perform list removal (which can also make
sure records don't get double-erased), and the "evict" handling should
be responsible only for memory freeing.

Link: https://lore.kernel.org/lkml/20200506152114.50375-8-keescook@chromium.org/
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-05-12 09:15:29 -07:00
Kees Cook
6248a0666c pstore: Add proper unregister lock checking
The pstore backend lock wasn't being used during pstore_unregister().
Add sanity check and locking.

Link: https://lore.kernel.org/lkml/20200506152114.50375-7-keescook@chromium.org/
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-05-12 09:15:11 -07:00