Commit Graph

339 Commits

Author SHA1 Message Date
Christoph Hellwig a75d30c772 fs/locks: pass kernel struct flock to fcntl_getlk/setlk
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>
2017-05-27 06:07:19 -04:00
Mauro Carvalho Chehab 80b79dd0e2 fs: locks: Fix some troubles at kernel-doc comments
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>
2017-05-27 06:07:18 -04:00
Benjamin Coddington 50f2112cf7 locks: Set FL_CLOSE when removing flock locks on close()
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>
2017-04-21 10:45:01 -04:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
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>
2016-12-24 11:46:01 -08:00
Peter Zijlstra 5f43086bb9 locking, fs/locks: Add missing file_sem locks
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>
2016-10-18 12:21:28 +02:00
Linus Torvalds 101105b171 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
2016-10-10 20:16:43 -07:00
Linus Torvalds abb5a14fa2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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()
  ...
2016-10-10 13:04:49 -07:00
Linus Torvalds c35bcfd8e4 File locking related changes for v4.9
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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
2016-10-04 13:36:19 -07:00
Deepa Dinamani c2050a454c fs: Replace current_fs_time() with current_time()
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>
2016-09-27 21:06:22 -04:00
Peter Zijlstra 87709e28dc fs/locks: Use percpu_down_read_preempt_disable()
Avoid spurious preemption.

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>
2016-09-22 15:25:54 +02:00
Peter Zijlstra 7c3f654d8e fs/locks: Replace lg_local with a per-cpu spinlock
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>
2016-09-22 15:25:53 +02:00
Peter Zijlstra aba3766073 fs/locks: Replace lg_global with a percpu-rwsem
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>
2016-09-22 15:25:53 +02:00
Miklos Szeredi 4d0c5ba2ff vfs: do get_write_access() on upper layer of overlayfs
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>
2016-09-16 12:44:21 +02:00
Miklos Szeredi c568d68341 locks: fix file locking on overlayfs
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>
2016-09-16 12:44:20 +02:00
Nikolay Borisov d67fd44f69 locks: Filter /proc/locks output on proc pid ns
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>
2016-08-18 13:49:41 -04:00
Miklos Szeredi 6343a21208 locks: use file_inode()
(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>
2016-07-01 10:24:18 -04:00
Al Viro 5955102c99 wrappers for ->i_mutex access
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>
2016-01-22 18:04:28 -05:00
Linus Torvalds fce205e9da Merge branch 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
2016-01-12 16:30:34 -08:00
Jeff Layton b4d629a39e locks: rename __posix_lock_file to posix_lock_inode
...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>
2016-01-08 11:38:30 -05:00
Jeff Layton e24dadab08 locks: prink more detail when there are leaked locks
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>
2016-01-08 11:38:25 -05:00
Jeff Layton f27a0fe083 locks: pass inode pointer to locks_free_lock_context
...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>
2016-01-08 11:38:19 -05:00
Jeff Layton 1890910fd0 locks: sprinkle some tracepoints around the file locking code
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>
2016-01-08 11:38:13 -05:00
Jeff Layton 0752ba807b locks: don't check for race with close when setting OFD lock
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>
2016-01-08 11:38:07 -05:00
Jeff Layton 7f3697e24d locks: fix unlock when fcntl_setlk races with a close
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>
2016-01-07 20:32:48 -05:00
Paul Gortmaker 9189922675 fs: make locks.c explicitly non-modular
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>
2015-12-18 07:05:06 -05:00
Christoph Hellwig acc15575e7 locks: new locks_mandatory_area calling convention
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>
2015-12-07 23:09:16 -05:00
Geliang Tang 8ace5dfb98 locks: use list_first_entry_or_null()
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>
2015-11-18 09:21:49 -05:00
Jeff Layton 9e8925b67a locks: Allow disabling mandatory locking at compile time
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>
2015-11-16 09:49:34 -05:00
Benjamin Coddington 616fb38fa7 locks: cleanup posix_lock_inode_wait and flock_lock_inode_wait
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>
2015-10-22 14:57:42 -04:00
Benjamin Coddington 4f6563677a Move locks API users to locks_lock_inode_wait()
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>
2015-10-22 14:57:36 -04:00
Benjamin Coddington e55c34a66f locks: introduce locks_lock_inode_wait()
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>
2015-10-22 14:57:20 -04:00
Benjamin Coddington 6ca7d91012 locks: Use more file_inode and fix a comment
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-10-15 09:07:07 -04:00
Dmitry Vyukov 128a378522 fs: fix data races on inode->i_flctx
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>
2015-09-21 07:27:35 -04:00
Randy Dunlap 7fadc59cc8 fs: fix fs/locks.c kernel-doc warning
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>
2015-08-31 16:27:25 -04:00
Jeff Layton ee296d7c57 locks: inline posix_lock_file_wait and flock_lock_file_wait
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>
2015-07-13 06:29:11 -04:00
Jeff Layton 29d01b22ea locks: new helpers - flock_lock_inode_wait and posix_lock_inode_wait
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>
2015-07-13 06:29:11 -04:00
Jeff Layton bcd7f78d07 locks: have flock_lock_file take an inode pointer instead of a filp
...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>
2015-07-13 06:29:11 -04:00
Andrey Vagin 6c8c90319c proc: show locks in /proc/pid/fdinfo/X
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>
2015-04-17 09:04:12 -04:00
Jeff Layton 0429c2b5c1 locks: use cmpxchg to assign i_flctx pointer
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>
2015-04-03 09:04:04 -04:00
Jeff Layton 3648888e90 locks: get rid of WE_CAN_BREAK_LSLK_NOW dead code
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>
2015-04-03 09:04:04 -04:00
Jeff Layton cae80b305e locks: change lm_get_owner and lm_put_owner prototypes
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>
2015-04-03 09:04:04 -04:00
Jeff Layton 5c1c669a1b locks: don't allocate a lock context for an F_UNLCK request
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>
2015-04-03 09:04:03 -04:00
Daniel Wagner 663d5af750 locks: Add lockdep assertion for blocked_lock_lock
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>
2015-04-03 09:04:03 -04:00
Jeff Layton 9b8c86956d locks: remove extraneous IS_POSIX and IS_FLOCK tests
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>
2015-04-03 09:04:02 -04:00
Daniel Wagner 9cd29044bd locks: Remove unnecessary IS_POSIX test
Since following change

commit bd61e0a9c8
Author: Jeff Layton <jlayton@primarydata.com>
Date:   Fri Jan 16 15:05:55 2015 -0500

    locks: convert posix locks to file_lock_context

all Posix locks are kept on their a separate list, so the test is
redudant.

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Jeff Layton <jlayton@primarydata.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-04-03 09:04:02 -04:00
Yan, Zheng a901125c65 locks: fix file_lock deletion inside loop
locks_delete_lock_ctx() is called inside the loop, so we
should use list_for_each_entry_safe.

Fixes: 8634b51f6c (locks: convert lease handling to file_lock_context)
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-03-27 07:18:20 -04:00
Jeff Layton a9b1b455c5 locks: fix generic_delete_lease tracepoint to use victim pointer
It's possible that "fl" won't point at a valid lock at this point, so
use "victim" instead which is either a valid lock or NULL.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-03-14 09:45:35 -04:00
Jeff Layton 0164bf0239 locks: fix fasync_struct memory leak in lease upgrade/downgrade handling
Commit 8634b51f6c (locks: convert lease handling to file_lock_context)
introduced a regression in the handling of lease upgrade/downgrades.

In the event that we already have a lease on a file and are going to
either upgrade or downgrade it, we skip doing any list insertion or
deletion and simply re-call lm_setup on the existing lease.

As of commit 8634b51f6c however, we end up calling lm_setup on the
lease that was passed in, instead of on the existing lease. This causes
us to leak the fasync_struct that was allocated in the event that there
was not already an existing one (as it always appeared that there
wasn't one).

Fixes: 8634b51f6c (locks: convert lease handling to file_lock_context)
Reported-and-Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-03-04 17:34:32 -05:00
Jeff Layton 2e2f756f81 locks: fix list insertion when lock is split in two
In the case where we're splitting a lock in two, the current code
the new "left" lock in the incorrect spot. It's inserted just
before "right" when it should instead be inserted just before the
new lock.

When we add a new lock, set "fl" to that value so that we can
add "left" before it.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-02-17 17:08:23 -05:00
Jeff Layton 267f112858 locks: remove conditional lock release in middle of flock_lock_file
As Linus pointed out:

    Say we have an existing flock, and now do a new one that conflicts. I
    see what looks like three separate bugs.

     - We go through the first loop, find a lock of another type, and
    delete it in preparation for replacing it

     - we *drop* the lock context spinlock.

     - BUG #1? So now there is no lock at all, and somebody can come in
    and see that unlocked state. Is that really valid?

     - another thread comes in while the first thread dropped the lock
    context lock, and wants to add its own lock. It doesn't see the
    deleted or pending locks, so it just adds it

     - the first thread gets the context spinlock again, and adds the lock
    that replaced the original

     - BUG #2? So now there are *two* locks on the thing, and the next
    time you do an unlock (or when you close the file), it will only
    remove/replace the first one.

...remove the "drop the spinlock" code in the middle of this function as
it has always been suspicious. This should eliminate the potential race
that can leave two locks for the same struct file on the list.

He also pointed out another thing as a bug -- namely that you
flock_lock_file removes the lock from the list unconditionally when
doing a lock upgrade, without knowing whether it'll be able to set the
new lock. Bruce pointed out that this is expected behavior and may help
prevent certain deadlock situations.

We may want to revisit that at some point, but it's probably best that
we do so in the context of a different patchset.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-02-17 15:23:09 -05:00
Jeff Layton c4e136cda1 locks: only remove leases associated with the file being closed
We don't want to remove all leases just because one filp was closed.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-02-17 15:22:57 -05:00
Jeff Layton e084c1bd40 Revert "locks: keep a count of locks on the flctx lists"
This reverts commit 9bd0f45b70.

Linus rightly pointed out that I failed to initialize the counters
when adding them, so they don't work as expected. Just revert this
patch for now.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-02-16 14:32:03 -05:00
Christoph Hellwig 11afe9f76e fs: add FL_LAYOUT lease type
This (ab-)uses the file locking code to allow filesystems to recall
outstanding pNFS layouts on a file.  This new lease type is similar but
not quite the same as FL_DELEG.  A FL_LAYOUT lease can always be granted,
an a per-filesystem lock (XFS iolock for the initial implementation)
ensures not FL_LAYOUT leases granted when we would need to recall them.

Also included are changes that allow multiple outstanding read
leases of different types on the same file as long as they have a
differnt owner.  This wasn't a problem until now as nfsd never set
FL_LEASE leases, and no one else used FL_DELEG leases, but given that
nfsd will also issues FL_LAYOUT leases we will have to handle it now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2015-02-02 18:09:38 +01:00
Christoph Hellwig 2ab99ee124 fs: track fl_owner for leases
Just like for other lock types we should allow different owners to have
a read lease on a file.  Currently this can't happen, but with the addition
of pNFS layout leases we'll need this feature.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2015-02-02 18:09:38 +01:00
Jeff Layton 8116bf4cb6 locks: update comments that refer to inode->i_flock
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2015-01-21 20:44:01 -05:00
Jeff Layton 3d8e560de4 locks: consolidate NULL i_flctx checks in locks_remove_file
We have each of the locks_remove_* variants doing this individually.
Have the caller do it instead, and have locks_remove_flock and
locks_remove_lease just assume that it's a valid pointer.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2015-01-16 16:08:50 -05:00
Jeff Layton 9bd0f45b70 locks: keep a count of locks on the flctx lists
This makes things a bit more efficient in the cifs and ceph lock
pushing code.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 16:08:50 -05:00
Jeff Layton 7448cc37b1 locks: clean up the lm_change prototype
Now that we use standard list_heads for tracking leases, we can have
lm_change take a pointer to the lease to be modified instead of a
double pointer.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 16:08:50 -05:00
Jeff Layton 6109c85037 locks: add a dedicated spinlock to protect i_flctx lists
We can now add a dedicated spinlock without expanding struct inode.
Change to using that to protect the various i_flctx lists.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 16:08:49 -05:00
Jeff Layton 8634b51f6c locks: convert lease handling to file_lock_context
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 16:08:17 -05:00
Jeff Layton bd61e0a9c8 locks: convert posix locks to file_lock_context
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 16:08:16 -05:00
Jeff Layton 5263e31e45 locks: move flock locks to file_lock_context
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 15:09:25 -05:00
Jeff Layton 4a075e39c8 locks: add a new struct file_locking_context pointer to struct inode
The current scheme of using the i_flock list is really difficult to
manage. There is also a legitimate desire for a per-inode spinlock to
manage these lists that isn't the i_lock.

Start conversion to a new scheme to eventually replace the old i_flock
list with a new "file_lock_context" object.

We start by adding a new i_flctx to struct inode. For now, it lives in
parallel with i_flock list, but will eventually replace it. The idea is
to allocate a structure to sit in that pointer and act as a locus for
all things file locking.

We allocate a file_lock_context for an inode when the first lock is
added to it, and it's only freed when the inode is freed. We use the
i_lock to protect the assignment, but afterward it should mostly be
accessed locklessly.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 15:05:54 -05:00
Jeff Layton dd459bb197 locks: have locks_release_file use flock_lock_file to release generic flock locks
...instead of open-coding it and removing flock locks directly. This
helps consolidate the flock lock removal logic into a single spot.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2015-01-16 15:05:54 -05:00
Jeff Layton 6dee60f69d locks: add new struct list_head to struct file_lock
...that we can use to queue file_locks to per-ctx list_heads. Go ahead
and convert locks_delete_lock and locks_dispose_list to use it instead
of the fl_block list.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
2015-01-16 15:05:54 -05:00
NeilBrown 52d304eb4e locks: fix NULL-deref in generic_delete_lease
commit 0efaa7e82f
  locks: generic_delete_lease doesn't need a file_lock at all

moves the call to fl->fl_lmops->lm_change() to a place in the
code where fl might be a non-lease lock.
When that happens, fl_lmops is NULL and an Oops ensures.

So add an extra test to restore correct functioning.

Reported-by: Linda Walsh <suse@tlinx.org>
Link: https://bugzilla.suse.com/show_bug.cgi?id=912569
Cc: stable@vger.kernel.org (v3.18)
Fixes: 0efaa7e82f
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2015-01-13 07:00:55 -05:00
Jeff Layton 6e129d0068 locks: flock_make_lock should return a struct file_lock (or PTR_ERR)
Eliminate the need for a return pointer.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:13 -04:00
Jeff Layton 7ca76311fe locks: set fl_owner for leases to filp instead of current->files
Like flock locks, leases are owned by the file description. Now that the
i_have_this_lease check in __break_lease is gone, we don't actually use
the fl_owner for leases for anything. So, it's now safe to set this more
appropriately to the same value as the fl_file.

While we're at it, fix up the comments over the fl_owner_t definition
since they're rather out of date.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-10-07 14:06:13 -04:00
Jeff Layton 4d01b7f5e7 locks: give lm_break a return value
Christoph suggests:

   "Add a return value to lm_break so that the lock manager can tell the
    core code "you can delete this lease right now".  That gets rid of
    the games with the timeout which require all kinds of race avoidance
    code in the users."

Do that here and have the nfsd lease break routine use it when it detects
that there was a race between setting up the lease and it being broken.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:13 -04:00
Jeff Layton 03d12ddf84 locks: __break_lease cleanup in preparation of allowing direct removal of leases
Eliminate an unneeded "flock" variable. We can use "fl" as a loop cursor
everywhere. Add a any_leases_conflict helper function as well to
consolidate a bit of code.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:13 -04:00
Jeff Layton 843c6b2f4c locks: remove i_have_this_lease check from __break_lease
I think that the intent of this code was to ensure that a process won't
deadlock if it has one fd open with a lease on it and then breaks that
lease by opening another fd. In that case it'll treat the __break_lease
call as if it were non-blocking.

This seems wrong -- the process could (for instance) be multithreaded
and managing different fds via different threads. I also don't see any
mention of this limitation in the (somewhat sketchy) documentation.

Remove the check and the non-blocking behavior when i_have_this_lease
is true.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-10-07 14:06:13 -04:00
Jeff Layton c45198eda2 locks: move freeing of leases outside of i_lock
There was only one place where we still could free a file_lock while
holding the i_lock -- lease_modify. Add a new list_head argument to the
lm_change operation, pass in a private list when calling it, and fix
those callers to dispose of the list once the lock has been dropped.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:13 -04:00
Jeff Layton f82b4b6780 locks: move i_lock acquisition into generic_*_lease handlers
Now that we have a saner internal API for managing leases, we no longer
need to mandate that the inode->i_lock be held over most of the lease
code. Push it down into generic_add_lease and generic_delete_lease.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:13 -04:00
Jeff Layton 1c7dd2ff43 locks: define a lm_setup handler for leases
...and move the fasync setup into it for fcntl lease calls. At the same
time, change the semantics of how the file_lock double-pointer is
handled. Up until now, on a successful lease return you got a pointer to
the lock on the list. This is bad, since that pointer can no longer be
relied on as valid once the inode->i_lock has been released.

Change the code to instead just zero out the pointer if the lease we
passed in ended up being used. Then the callers can just check to see
if it's NULL after the call and free it if it isn't.

The priv argument has the same semantics. The lm_setup function can
zero the pointer out to signal to the caller that it should not be
freed after the function returns.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:12 -04:00
Jeff Layton e6f5c78930 locks: plumb a "priv" pointer into the setlease routines
In later patches, we're going to add a new lock_manager_operation to
finish setting up the lease while still holding the i_lock.  To do
this, we'll need to pass a little bit of info in the fcntl setlease
case (primarily an fasync structure). Plumb the extra pointer into
there in advance of that.

We declare this pointer as a void ** to make it clear that this is
private info, and that the caller isn't required to set this unless
the lm_setup specifically requires it.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:12 -04:00
Jeff Layton e51673aa5d locks: clean up vfs_setlease kerneldoc comments
Some of the latter paragraphs seem ambiguous and just plain wrong.
In particular the break_lease comment makes no sense. We call
break_lease (and break_deleg) from all sorts of vfs-layer functions,
so there is clearly such a method.

Also get rid of some of the other comments about what's needed for
a full implementation.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:12 -04:00
Jeff Layton 0efaa7e82f locks: generic_delete_lease doesn't need a file_lock at all
Ensure that it's OK to pass in a NULL file_lock double pointer on
a F_UNLCK request and convert the vfs_setlease F_UNLCK callers to
do just that.

Finally, turn the BUG_ON in generic_setlease into a WARN_ON_ONCE
with an error return. That's a problem we can handle without
crashing the box if it occurs.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:12 -04:00
Jeff Layton bfe8602436 locks: close potential race in lease_get_mtime
lease_get_mtime is called without the i_lock held, so there's no
guarantee about the stability of the list. Between the time when we
assign "flock" and then dereference it to check whether it's a lease
and for write, the lease could be freed.

Ensure that that doesn't occur by taking the i_lock before trying
to check the lease.

Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-10-07 14:06:12 -04:00
Jeff Layton e0b93eddfe security: make security_file_set_fowner, f_setown and __f_setown void return
security_file_set_fowner always returns 0, so make it f_setown and
__f_setown void return functions and fix up the error handling in the
callers.

Cc: linux-security-module@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-09-09 16:01:36 -04:00
Jeff Layton 699688a416 locks: remove lock_may_read and lock_may_write
There are no callers of these functions.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-09-09 16:01:09 -04:00
Kinglong Mee f328296e27 locks: Copy fl_lmops information for conflock in locks_copy_conflock()
Commit d5b9026a67 ([PATCH] knfsd: locks: flag NFSv4-owned locks) using
fl_lmops field in file_lock for checking nfsd4 lockowner.

But, commit 1a747ee0cc (locks: don't call ->copy_lock methods on return
of conflicting locks) causes the fl_lmops of conflock always be NULL.

Also, commit 0996905f93 (lockd: posix_test_lock() should not call
locks_copy_lock()) caused the fl_lmops of conflock always be NULL too.

Make sure copy the private information by fl_copy_lock() in struct
file_lock_operations, merge __locks_copy_lock() to fl_copy_lock().

Jeff advice, "Set fl_lmops on conflocks, but don't set fl_ops.
fl_ops are superfluous, since they are callbacks into the filesystem.
There should be no need to bother the filesystem at all with info
in a conflock. But, lock _ownership_ matters for conflocks and that's
indicated by the fl_lmops. So you really do want to copy the fl_lmops
for conflocks I think."

v5: add missing calling of locks_release_private() in nlmsvc_testlock()
v4: only copy fl_lmops for conflock, don't copy fl_ops

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-09-09 16:01:09 -04:00
Kinglong Mee 5c97d7b147 locks: New ops in lock_manager_operations for get/put owner
NFSD or other lockmanager may increase the owner's reference,
so adds two new options for copying and releasing owner.

v5: change order from 2/6 to 3/6
v4: rename lm_copy_owner/lm_release_owner to lm_get_owner/lm_put_owner

Reviewed-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-09-09 16:01:09 -04:00
Kinglong Mee 3fe0fff18f locks: Rename __locks_copy_lock() to locks_copy_conflock()
Jeff advice, " Right now __locks_copy_lock is only used to copy
conflocks. It would be good to rename that to something more
distinct (i.e.locks_copy_conflock), to make it clear that we're
generating a conflock there."

v5: change order from 3/6 to 2/6
v4: new patch only renaming function name

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-09-09 16:01:09 -04:00
Jeff Layton f39b913cee locks: pass correct "before" pointer to locks_unlink_lock in generic_add_lease
The argument to locks_unlink_lock can't be just any pointer to a
pointer. It must be a pointer to the fl_next field in the previous
lock in the list.

Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2014-09-09 16:00:51 -04:00
Jeff Layton 2dfb928f7e locks: move locks_free_lock calls in do_fcntl_add_lease outside spinlock
There's no need to call locks_free_lock here while still holding the
i_lock. Defer that until the lock has been dropped.

Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-08-14 10:07:47 -04:00
Jeff Layton ed9814d858 locks: defer freeing locks in locks_delete_lock until after i_lock has been dropped
In commit 72f98e7255 (locks: turn lock_flocks into a spinlock), we
moved from using the BKL to a global spinlock. With this change, we lost
the ability to block in the fl_release_private operation.

This is problematic for NFS (and probably some other filesystems as
well). Add a new list_head argument to locks_delete_lock. If that
argument is non-NULL, then queue any locks that we want to free to the
list instead of freeing them.

Then, add a new locks_dispose_list function that will walk such a list
and call locks_free_lock on them after the i_lock has been dropped.

Finally, change all of the callers of locks_delete_lock to pass in a
list_head, except for lease_modify. That function can be called long
after the i_lock has been acquired. Deferring the freeing of a lease
after unlocking it in that function is non-trivial until we overhaul
some of the spinlocking in the lease code.

Currently though, no filesystem that sets fl_release_private supports
leases, so this is not currently a problem. We'll eventually want to
make the same change in the lease code, but it needs a lot more work
before we can reasonably do so.

Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-08-14 10:07:47 -04:00
Jeff Layton b84d49f944 locks: don't reuse file_lock in __posix_lock_file
Currently in the case where a new file lock completely replaces the old
one, we end up overwriting the existing lock with the new info. This
means that we have to call fl_release_private inside i_lock. Change the
code to instead copy the info to new_fl, insert that lock into the
correct spot and then delete the old lock. In a later patch, we'll defer
the freeing of the old lock until after the i_lock has been dropped.

Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-08-14 10:07:47 -04:00
Jeff Layton 566709bd62 locks: don't call locks_release_private from locks_copy_lock
All callers of locks_copy_lock pass in a brand new file_lock struct, so
there's no need to call locks_release_private on it. Replace that with
a warning that fires in the event that we receive a target lock that
doesn't look like it's properly initialized.

Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-08-11 14:24:22 -04:00
Jeff Layton 8144f1f699 locks: show delegations as "DELEG" in /proc/locks
Now that they are a distinct lease type, show them as such.

Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-08-11 13:36:54 -04:00
Christoph Hellwig 73a8f5f7e6 locks: purge fl_owner_t from fs/locks.c
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-07-13 21:39:07 -04:00
Jeff Layton 0c27362998 locks: set fl_owner for leases back to current->files
This fixes a regression due to commit 130d1f956a (locks: ensure that
fl_owner is always initialized properly in flock and lease codepaths). I
had mistakenly thought that the fl_owner wasn't used in the lease code,
but I missed the place in __break_lease that does use it.

The i_have_this_lease check in generic_add_lease uses it. While I'm not
sure that check is terribly helpful [1], reset it back to using
current->files in order to ensure that there's no behavior change here.

[1]: leases are owned by the file description. It's possible that this
     is a threaded program, and the lease breaker and the task that
     would handle the signal are different, even if they have the same
     file table. So, there is the potential for false positives with
     this check.

Fixes: 130d1f956a (locks: ensure that fl_owner is always initialized properly in flock and lease codepaths)
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
2014-06-10 12:29:05 -04:00
Jeff Layton 62af4f1f7d locks: add some tracepoints in the lease handling code
v2: add a __break_lease tracepoint for non-blocking case

Recently, I needed these to help track down a softlockup when recalling a
delegation, but they might be helpful in other situations as well.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
2014-06-02 08:09:30 -04:00
Fabian Frederick 5315c26a6c fs/locks.c: replace seq_printf by seq_puts
Replace seq_printf where possible

Cc: Jeff Layton <jlayton@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
2014-06-02 08:09:29 -04:00
Jeff Layton 130d1f956a locks: ensure that fl_owner is always initialized properly in flock and lease codepaths
Currently, the fl_owner isn't set for flock locks. Some filesystems use
byte-range locks to simulate flock locks and there is a common idiom in
those that does:

    fl->fl_owner = (fl_owner_t)filp;
    fl->fl_start = 0;
    fl->fl_end = OFFSET_MAX;

Since flock locks are generally "owned" by the open file description,
move this into the common flock lock setup code. The fl_start and fl_end
fields are already set appropriately, so remove the unneeded setting of
that in flock ops in those filesystems as well.

Finally, the lease code also sets the fl_owner as if they were owned by
the process and not the open file description. This is incorrect as
leases have the same ownership semantics as flock locks. Set them the
same way. The lease code doesn't actually use the fl_owner value for
anything, so this is more for consistency's sake than a bugfix.

Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (Staging portion)
Acked-by: J. Bruce Fields <bfields@fieldses.org>
2014-06-02 08:09:29 -04:00
Jeff Layton cf01f4eef9 locks: only validate the lock vs. f_mode in F_SETLK codepaths
v2: replace missing break in switch statement (as pointed out by Dave
    Jones)

commit bce7560d49 (locks: consolidate checks for compatible
filp->f_mode values in setlk handlers) introduced a regression in the
F_GETLK handler.

flock64_to_posix_lock is a shared codepath between F_GETLK and F_SETLK,
but the f_mode checks should only be applicable to the F_SETLK codepaths
according to POSIX.

Instead of just reverting the patch, add a new function to do this
checking and have the F_SETLK handlers call it.

Cc: Dave Jones <davej@redhat.com>
Reported-and-Tested-by: Reuben Farrelly <reuben@reub.net>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
2014-05-09 11:41:54 -04:00
Jeff Layton cff2fce58b locks: rename FL_FILE_PVT and IS_FILE_PVT to use "*_OFDLCK" instead
File-private locks have been re-christened as "open file description"
locks.  Finish the symbol name cleanup in the internal implementation.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
2014-04-23 16:17:03 -04:00
Jeff Layton 0d3f7a2dd2 locks: rename file-private locks to "open file description locks"
File-private locks have been merged into Linux for v3.15, and *now*
people are commenting that the name and macro definitions for the new
file-private locks suck.

...and I can't even disagree. The names and command macros do suck.

We're going to have to live with these for a long time, so it's
important that we be happy with the names before we're stuck with them.
The consensus on the lists so far is that they should be rechristened as
"open file description locks".

The name isn't a big deal for the kernel, but the command macros are not
visually distinct enough from the traditional POSIX lock macros. The
glibc and documentation folks are recommending that we change them to
look like F_OFD_{GETLK|SETLK|SETLKW}. That lessens the chance that a
programmer will typo one of the commands wrong, and also makes it easier
to spot this difference when reading code.

This patch makes the following changes that I think are necessary before
v3.15 ships:

1) rename the command macros to their new names. These end up in the uapi
   headers and so are part of the external-facing API. It turns out that
   glibc doesn't actually use the fcntl.h uapi header, but it's hard to
   be sure that something else won't. Changing it now is safest.

2) make the the /proc/locks output display these as type "OFDLCK"

Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Carlos O'Donell <carlos@redhat.com>
Cc: Stefan Metzmacher <metze@samba.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Frank Filz <ffilzlnx@mindspring.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
2014-04-22 08:23:58 -04:00
Jeff Layton f1c6bb2cb8 locks: allow __break_lease to sleep even when break_time is 0
A fl->fl_break_time of 0 has a special meaning to the lease break code
that basically means "never break the lease". knfsd uses this to ensure
that leases don't disappear out from under it.

Unfortunately, the code in __break_lease can end up passing this value
to wait_event_interruptible as a timeout, which prevents it from going
to sleep at all. This makes __break_lease to spin in a tight loop and
causes soft lockups.

Fix this by ensuring that we pass a minimum value of 1 as a timeout
instead.

Cc: <stable@vger.kernel.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Reported-by: Terry Barnaby <terry1@beam.ltd.uk>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
2014-04-15 06:17:49 -04:00
Jeff Layton 29723adee1 locks: make locks_mandatory_area check for file-private locks
Allow locks_mandatory_area() to handle file-private locks correctly.
If there is a file-private lock set on an open file and we're doing I/O
via the same, then that should not cause anything to block.

Handle this by first doing a non-blocking FL_ACCESS check for a
file-private lock, and then fall back to checking for a classic POSIX
lock (and possibly blocking).

Note that this approach is subject to the same races that have always
plagued mandatory locking on Linux.

Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
2014-03-31 08:24:43 -04:00
Jeff Layton d7a06983a0 locks: fix locks_mandatory_locked to respect file-private locks
As Trond pointed out, you can currently deadlock yourself by setting a
file-private lock on a file that requires mandatory locking and then
trying to do I/O on it.

Avoid this problem by plumbing some knowledge of file-private locks into
the mandatory locking code. In order to do this, we must pass down
information about the struct file that's being used to
locks_verify_locked.

Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
2014-03-31 08:24:43 -04:00