But it's also a fairly small update this time around. Some cleanup,
RDMA fixes, overlayfs fixes, and a fix for an NFSv4 state bug.
The bigger deal for nfsd this time around is Jeff Layton's
already-merged i_version patches. This series has a minor conflict with
that one, and the resolution should be obvious. (Stephen Rothwell has
been carrying it in linux-next for what it's worth.)
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Merge tag 'nfsd-4.16' of git://linux-nfs.org/~bfields/linux
Pull nfsd update from Bruce Fields:
"A fairly small update this time around. Some cleanup, RDMA fixes,
overlayfs fixes, and a fix for an NFSv4 state bug.
The bigger deal for nfsd this time around was Jeff Layton's
already-merged i_version patches"
* tag 'nfsd-4.16' of git://linux-nfs.org/~bfields/linux:
svcrdma: Fix Read chunk round-up
NFSD: hide unused svcxdr_dupstr()
nfsd: store stat times in fill_pre_wcc() instead of inode times
nfsd: encode stat->mtime for getattr instead of inode->i_mtime
nfsd: return RESOURCE not GARBAGE_ARGS on too many ops
nfsd4: don't set lock stateid's sc_type to CLOSED
nfsd: Detect unhashed stids in nfsd4_verify_open_stid()
sunrpc: remove dead code in svc_sock_setbufsize
svcrdma: Post Receives in the Receive completion handler
nfsd4: permit layoutget of executable-only files
lockd: convert nlm_rqst.a_count from atomic_t to refcount_t
lockd: convert nlm_lockowner.count from atomic_t to refcount_t
lockd: convert nsm_handle.sm_count from atomic_t to refcount_t
The values of stat->mtime and inode->i_mtime may differ for overlayfs
and stat->mtime is the correct value to use when encoding getattr.
This is also consistent with the fact that other attr times are also
encoded from stat values.
Both callers of lease_get_mtime() already have the value of stat->mtime,
so the only needed change is that lease_get_mtime() will not overwrite
this value with inode->i_mtime in case the inode does not have an
exclusive lease.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This is a pure automated search-and-replace of the internal kernel
superblock flags.
The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.
Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.
The script to do this was:
# places to look in; re security/*: it generally should *not* be
# touched (that stuff parses mount(2) arguments directly), but
# there are two places where we really deal with superblock flags.
FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
include/linux/fs.h include/uapi/linux/bfs_fs.h \
security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
# the list of MS_... constants
SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
ACTIVE NOUSER"
SED_PROG=
for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done
# we want files that contain at least one of MS_...,
# with fs/namespace.c and fs/pnode.c excluded.
L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')
for f in $L; do sed -i $f $SED_PROG; done
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When locks.c moved to using file_lock_context, the check for any locks that
were not released was moved from the __fput() to destroy_inode() path in
commit 8634b51f6c ("locks: convert lease handling to file_lock_context").
This warning has been quite useful for catching bugs, particularly in NFS
where lock handling still sees some churn.
Let's bring back the warning for leaked locks on __fput, as this warning is
much more likely to be seen and reported by users.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Since commit c69899a17c "NFSv4: Update of VFS byte range lock must be
atomic with the stateid update", NFSv4 has been inserting locks in rpciod
worker context. The result is that the file_lock's fl_nspid is the
kworker's pid instead of the original userspace pid.
The fl_nspid is only used to represent the namespaced virtual pid number
when displaying locks or returning from F_GETLK. There's no reason to set
it for every inserted lock, since we can usually just look it up from
fl_pid. So, instead of looking up and holding struct pid for every lock,
let's just look up the virtual pid number from fl_pid when it is needed.
That means we can remove fl_nspid entirely.
The translaton and presentation of fl_pid should handle the following four
cases:
1 - F_GETLK on a remote file with a remote lock:
In this case, the filesystem should determine the l_pid to return here.
Filesystems should indicate that the fl_pid represents a non-local pid
value that should not be translated by returning an fl_pid <= 0.
2 - F_GETLK on a local file with a remote lock:
This should be the l_pid of the lock manager process, and translated.
3 - F_GETLK on a remote file with a local lock, and
4 - F_GETLK on a local file with a local lock:
These should be the translated l_pid of the local locking process.
Fuse was already doing the correct thing by translating the pid into the
caller's namespace. With this change we must update fuse to translate
to init's pid namespace, so that the locks API can then translate from
init's pid namespace into the pid namespace of the caller.
With this change, the locks API will expect that if a filesystem returns
a remote pid as opposed to a local pid for F_GETLK, that remote pid will
be <= 0. This signifies that the pid is remote, and the locks API will
forego translating that pid into the pid namespace of the local calling
process.
Finally, we convert remote filesystems to present remote pids using
negative numbers. Have lustre, 9p, ceph, cifs, and dlm negate the remote
pid returned for F_GETLK lock requests.
Since local pids will never be larger than PID_MAX_LIMIT (which is
currently defined as <= 4 million), but pid_t is an unsigned int, we
should have plenty of room to represent remote pids with negative
numbers if we assume that remote pid numbers are similarly limited.
If this is not the case, then we run the risk of having a remote pid
returned for which there is also a corresponding local pid. This is a
problem we have now, but this patch should reduce the chances of that
occurring, while also returning those remote pid numbers, for whatever
that may be worth.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Struct file_lock is fairly large, so let's save some space on the stack by
using an allocation for struct file_lock in fcntl_getlk(), just as we do
for fcntl_setlk().
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
This will make it easier to implement a sane compat fcntl syscall.
[ jlayton: fix undeclared identifiers in 32-bit fcntl64 syscall handler ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
There are a few syntax violations that cause outputs of
a few comments to not be properly parsed in ReST format.
No functional changes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Set FL_CLOSE in fl_flags as in locks_remove_posix() when clearing locks.
NFS will check for this flag to ensure an unlock is sent in a following
patch.
Fuse handles flock and posix locks differently for FL_CLOSE, and so
requires a fixup to retain the existing behavior for flock.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I overlooked a few code-paths that can lead to
locks_delete_global_locks().
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Bruce Fields <bfields@fieldses.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-fsdevel@vger.kernel.org
Cc: syzkaller <syzkaller@googlegroups.com>
Link: http://lkml.kernel.org/r/20161008081228.GF3142@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning
Pull misc vfs updates from Al Viro:
"Assorted misc bits and pieces.
There are several single-topic branches left after this (rename2
series from Miklos, current_time series from Deepa Dinamani, xattr
series from Andreas, uaccess stuff from from me) and I'd prefer to
send those separately"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
proc: switch auxv to use of __mem_open()
hpfs: support FIEMAP
cifs: get rid of unused arguments of CIFSSMBWrite()
posix_acl: uapi header split
posix_acl: xattr representation cleanups
fs/aio.c: eliminate redundant loads in put_aio_ring_file
fs/internal.h: add const to ns_dentry_operations declaration
compat: remove compat_printk()
fs/buffer.c: make __getblk_slow() static
proc: unsigned file descriptors
fs/file: more unsigned file descriptors
fs: compat: remove redundant check of nr_segs
cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
cifs: don't use memcpy() to copy struct iov_iter
get rid of separate multipage fault-in primitives
fs: Avoid premature clearing of capabilities
fs: Give dentry to inode_change_ok() instead of inode
fuse: Propagate dentry down to inode_change_ok()
ceph: Propagate dentry down to inode_change_ok()
xfs: Propagate dentry down to inode_change_ok()
...
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Merge tag 'locks-v4.9-1' of git://git.samba.org/jlayton/linux
Pull file locking updates from Jeff Layton:
"Only a single patch from Nikolay this cycle, with a small change to
better handle /proc/locks in a containerized host"
* tag 'locks-v4.9-1' of git://git.samba.org/jlayton/linux:
locks: Filter /proc/locks output on proc pid ns
current_fs_time() uses struct super_block* as an argument.
As per Linus's suggestion, this is changed to take struct
inode* as a parameter instead. This is because the function
is primarily meant for vfs inode timestamps.
Also the function was renamed as per Arnd's suggestion.
Change all calls to current_fs_time() to use the new
current_time() function instead. current_fs_time() will be
deleted.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As Oleg suggested, replace file_lock_list with a structure containing
the hlist head and a spinlock.
This completely removes the lglock from fs/locks.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: der.herr@hofr.at
Cc: paulmck@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: tj@kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Replace the global part of the lglock with a percpu-rwsem.
Since fcl_lock is a spinlock and itself nests under i_lock, which too
is a spinlock we cannot acquire sleeping locks at
locks_{insert,remove}_global_locks().
We can however wrap all fcl_lock acquisitions with percpu_down_read
such that all invocations of locks_{insert,remove}_global_locks() have
that read lock held.
This allows us to replace the lg_global part of the lglock with the
write side of the rwsem.
In the absense of writers, percpu_{down,up}_read() are free of atomic
instructions. This further avoids the very long preempt-disable
regions caused by lglock on larger machines.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: der.herr@hofr.at
Cc: paulmck@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: tj@kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The problem with writecount is: we want consistent handling of it for
underlying filesystems as well as overlayfs. Making sure i_writecount is
correct on all layers is difficult. Instead this patch makes sure that
when write access is acquired, it's always done on the underlying writable
layer (called the upper layer). We must also make sure to look at the
writecount on this layer when checking for conflicting leases.
Open for write already updates the upper layer's writecount. Leaving only
truncate.
For truncate copy up must happen before get_write_access() so that the
writecount is updated on the upper layer. Problem with this is if
something fails after that, then copy-up was done needlessly. E.g. if
break_lease() was interrupted. Probably not a big deal in practice.
Another interesting case is if there's a denywrite on a lower file that is
then opened for write or truncated. With this patch these will succeed,
which is somewhat counterintuitive. But I think it's still acceptable,
considering that the copy-up does actually create a different file, so the
old, denywrite mapping won't be touched.
On non-overlayfs d_real() is an identity function and d_real_inode() is
equivalent to d_inode() so this patch doesn't change behavior in that case.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
This patch allows flock, posix locks, ofd locks and leases to work
correctly on overlayfs.
Instead of using the underlying inode for storing lock context use the
overlay inode. This allows locks to be persistent across copy-up.
This is done by introducing locks_inode() helper and using it instead of
file_inode() to get the inode in locking code. For non-overlayfs the two
are equivalent, except for an extra pointer dereference in locks_inode().
Since lock operations are in "struct file_operations" we must also make
sure not to call underlying filesystem's lock operations. Introcude a
super block flag MS_NOREMOTELOCK to this effect.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
On busy container servers reading /proc/locks shows all the locks
created by all clients. This can cause large latency spikes. In my
case I observed lsof taking up to 5-10 seconds while processing around
50k locks. Fix this by limiting the locks shown only to those created
in the same pidns as the one the proc fs was mounted in. When reading
/proc/locks from the init_pid_ns proc instance then perform no
filtering
[ jlayton: reformat comments for 80 columns ]
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
(Another one for the f_path debacle.)
ltp fcntl33 testcase caused an Oops in selinux_file_send_sigiotask.
The reason is that generic_add_lease() used filp->f_path.dentry->inode
while all the others use file_inode(). This makes a difference for files
opened on overlayfs since the former will point to the overlay inode the
latter to the underlying inode.
So generic_add_lease() added the lease to the overlay inode and
generic_delete_lease() removed it from the underlying inode. When the file
was released the lease remained on the overlay inode's lock list, resulting
in use after free.
Reported-by: Eryu Guan <eguan@redhat.com>
Fixes: 4bacc9c923 ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).
Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull vfs copy_file_range updates from Al Viro:
"Several series around copy_file_range/CLONE"
* 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
btrfs: use new dedupe data function pointer
vfs: hoist the btrfs deduplication ioctl to the vfs
vfs: wire up compat ioctl for CLONE/CLONE_RANGE
cifs: avoid unused variable and label
nfsd: implement the NFSv4.2 CLONE operation
nfsd: Pass filehandle to nfs4_preprocess_stateid_op()
vfs: pull btrfs clone API to vfs layer
locks: new locks_mandatory_area calling convention
vfs: Add vfs_copy_file_range() support for pagecache copies
btrfs: add .copy_file_range file operation
x86: add sys_copy_file_range to syscall tables
vfs: add copy_file_range syscall and vfs helper
...a more descriptive name and we can drop the double underscore prefix.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Right now, we just get WARN_ON_ONCE, which is not particularly helpful.
Have it dump some info about the locks and the inode to make it easier
to track down leaked locks in the future.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
...so we can print information about it if there are leaked locks.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Add some tracepoints around the POSIX locking code. These were useful
when tracking down problems when handling the race between setlk and
close.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
We don't clean out OFD locks on close(), so there's no need to check
for a race with them here. They'll get cleaned out at the same time
that flock locks are.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Dmitry reported that he was able to reproduce the WARN_ON_ONCE that
fires in locks_free_lock_context when the flc_posix list isn't empty.
The problem turns out to be that we're basically rebuilding the
file_lock from scratch in fcntl_setlk when we discover that the setlk
has raced with a close. If the l_whence field is SEEK_CUR or SEEK_END,
then we may end up with fl_start and fl_end values that differ from
when the lock was initially set, if the file position or length of the
file has changed in the interim.
Fix this by just reusing the same lock request structure, and simply
override fl_type value with F_UNLCK as appropriate. That ensures that
we really are unlocking the lock that was initially set.
While we're there, make sure that we do pop a WARN_ON_ONCE if the
removal ever fails. Also return -EBADF in this event, since that's
what we would have returned if the close had happened earlier.
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Fixes: c293621bbf (stale POSIX lock handling)
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
The Kconfig currently controlling compilation of this code is:
config FILE_LOCKING
bool "Enable POSIX file locking API" if EXPERT
...meaning that it currently is not being built as a module by anyone.
Lets remove the couple traces of modularity so that when reading the
driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering gets bumped to one level earlier when we
use the more appropriate fs_initcall here. However we've made similar
changes before without any fallout and none is expected here either.
Cc: Jeff Layton <jlayton@poochiereds.net>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Pass a loff_t end for the last byte instead of the 32-bit count
parameter to allow full file clones even on 32-bit architectures.
While we're at it also simplify the read/write selection.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Simplify the code with list_first_entry_or_null().
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Mandatory locking appears to be almost unused and buggy and there
appears no real interest in doing anything with it. Since effectively
no one uses the code and since the code is buggy let's allow it to be
disabled at compile time. I would just suggest removing the code but
undoubtedly that will break some piece of userspace code somewhere.
For the distributions that don't care about this piece of code
this gives a nice starting point to make mandatory locking go away.
Cc: Benjamin Coddington <bcodding@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jeff Layton <jeff.layton@primarydata.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
All callers use locks_lock_inode_wait() instead.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Instead of having users check for FL_POSIX or FL_FLOCK to call the correct
locks API function, use the check within locks_lock_inode_wait(). This
allows for some later cleanup.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Users of the locks API commonly call either posix_lock_file_wait() or
flock_lock_file_wait() depending upon the lock type. Add a new function
locks_lock_inode_wait() which will check and call the correct function for
the type of lock passed in.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
locks_get_lock_context() uses cmpxchg() to install i_flctx.
cmpxchg() is a release operation which is correct. But it uses
a plain load to load i_flctx. This is incorrect. Subsequent loads
from i_flctx can hoist above the load of i_flctx pointer itself
and observe uninitialized garbage there. This in turn can lead
to corruption of ctx->flc_lock and other members.
Documentation/memory-barriers.txt explicitly requires to use
a barrier in such context:
"A load-load control dependency requires a full read memory barrier".
Use smp_load_acquire() in locks_get_lock_context() and in bunch
of other functions that can proceed concurrently with
locks_get_lock_context().
The data race was found with KernelThreadSanitizer (KTSAN).
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Fix kernel-doc warnings in fs/locks.c:
Warning(..//fs/locks.c:1577): No description found for parameter 'flags'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
They just call file_inode and then the corresponding *_inode_file_wait
function. Just make them static inlines instead.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Allow callers to pass in an inode instead of a filp.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: "J. Bruce Fields" <bfields@fieldses.org>
Tested-by: "J. Bruce Fields" <bfields@fieldses.org>
...and rename it to better describe how it works.
In order to fix a use-after-free in NFS, we need to be able to remove
locks from an inode after the filp associated with them may have already
been freed. flock_lock_file already only dereferences the filp to get to
the inode, so just change it so the callers do that.
All of the callers already pass in a lock request that has the fl_file
set properly, so we don't need to pass it in individually. With that
change it now only dereferences the filp to get to the inode, so just
push that out to the callers.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: "J. Bruce Fields" <bfields@fieldses.org>
Tested-by: "J. Bruce Fields" <bfields@fieldses.org>
Let's show locks which are associated with a file descriptor in
its fdinfo file.
Currently we don't have a reliable way to determine who holds a lock. We
can find some information in /proc/locks, but PID which is reported there
can be wrong. For example, a process takes a lock, then forks a child and
dies. In this case /proc/locks contains the parent pid, which can be
reused by another process.
$ cat /proc/locks
...
6: FLOCK ADVISORY WRITE 324 00:13:13431 0 EOF
...
$ ps -C rpcbind
PID TTY TIME CMD
332 ? 00:00:00 rpcbind
$ cat /proc/332/fdinfo/4
pos: 0
flags: 0100000
mnt_id: 22
lock: 1: FLOCK ADVISORY WRITE 324 00:13:13431 0 EOF
$ ls -l /proc/332/fd/4
lr-x------ 1 root root 64 Mar 5 14:43 /proc/332/fd/4 -> /run/rpcbind.lock
$ ls -l /proc/324/fd/
total 0
lrwx------ 1 root root 64 Feb 27 14:50 0 -> /dev/pts/0
lrwx------ 1 root root 64 Feb 27 14:50 1 -> /dev/pts/0
lrwx------ 1 root root 64 Feb 27 14:49 2 -> /dev/pts/0
You can see that the process with the 324 pid doesn't hold the lock.
This information is required for proper dumping and restoring file
locks.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During the v3.20/v4.0 cycle, I had originally had the code manage the
inode->i_flctx pointer using a compare-and-swap operation instead of the
i_lock.
Sasha Levin though hit a problem while testing with trinity that made me
believe that that wasn't safe. At the time, changing the code to protect
the i_flctx pointer seemed to fix the issue, but I now think that was
just coincidence.
The issue was likely the same race that Kirill Shutemov hit while
testing the pre-rc1 v4.0 kernel and that Linus spotted. Due to the way
that the spinlock was dropped in the middle of flock_lock_file, you
could end up with multiple flock locks for the same struct file on the
inode.
Reinstate the use of a CAS operation to assign this pointer since it's
likely to be more efficient and gets the i_lock completely out of the
file locking business.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
As Bruce points out, there's no compelling reason to change /proc/locks
output at this point. If we did want to do this, then we'd almost
certainly want to introduce a new file to display this info (maybe via
debugfs?).
Let's remove the dead WE_CAN_BREAK_LSLK_NOW ifdef here and just plan to
stay with the legacy format.
Reported-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
The current prototypes for these operations are somewhat awkward as they
deal with fl_owners but take struct file_lock arguments. In the future,
we'll want to be able to take references without necessarily dealing
with a struct file_lock.
Change them to take fl_owner_t arguments instead and have the callers
deal with assigning the values to the file_lock structs.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
In the event that we get an F_UNLCK request on an inode that has no lock
context, there is no reason to allocate one. Change
locks_get_lock_context to take a "type" pointer and avoid allocating a
new context if it's F_UNLCK.
Then, fix the callers to return appropriately if that function returns
NULL.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Annonate insert, remove and iterate function that we need
blocked_lock_lock held.
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
We know that the locks being passed into this function are of the
correct type, now that they live on their own lists.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
